[Federal Register Volume 79, Number 81 (Monday, April 28, 2014)]
[Rules and Regulations]
[Pages 23413-23886]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-06954]



[[Page 23413]]

Vol. 79

Monday,

No. 81

April 28, 2014

Part II





 Environmental Protection Agency





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40 CFR Parts 79, 80, 85, et al.





 Control of Air Pollution From Motor Vehicles: Tier 3 Motor Vehicle 
Emission and Fuel Standards; Final Rule

Federal Register / Vol. 79 , No. 81 / Monday, April 28, 2014 / Rules 
and Regulations

[[Page 23414]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 79, 80, 85, 86, 600, 1036, 1037, 1039, 1042, 1048, 
1054, 1065, and 1066

[EPA-HQ-OAR-2011-0135; FRL 9906-86-OAR]
RIN 2060-AQ86


Control of Air Pollution From Motor Vehicles: Tier 3 Motor 
Vehicle Emission and Fuel Standards

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This action establishes more stringent vehicle emissions 
standards and will reduce the sulfur content of gasoline beginning in 
2017, as part of a systems approach to addressing the impacts of motor 
vehicles and fuels on air quality and public health. The gasoline 
sulfur standard will make emission control systems more effective for 
both existing and new vehicles, and will enable more stringent vehicle 
emissions standards. The vehicle standards will reduce both tailpipe 
and evaporative emissions from passenger cars, light-duty trucks, 
medium-duty passenger vehicles, and some heavy-duty vehicles. This will 
result in significant reductions in pollutants such as ozone, 
particulate matter, and air toxics across the country and help state 
and local agencies in their efforts to attain and maintain health-based 
National Ambient Air Quality Standards. Motor vehicles are an important 
source of exposure to air pollution both regionally and near roads. 
These vehicle standards are intended to harmonize with California's Low 
Emission Vehicle program, thus creating a federal vehicle emissions 
program that will allow automakers to sell the same vehicles in all 50 
states. The vehicle standards will be implemented over the same 
timeframe as the greenhouse gas/fuel efficiency standards for light-
duty vehicles (promulgated by EPA and the National Highway Safety 
Administration in 2012), as part of a comprehensive approach toward 
regulating emissions from motor vehicles.

DATES: This final rule is effective on June 27, 2014. The incorporation 
by reference of certain publications listed in this regulation is 
approved by the Director of the Federal Register as of June 27, 2014.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. EPA-HQ-OAR-2011-0135. All documents in the docket are listed on the 
www.regulations.gov Web site. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, is not placed on the Internet and will be 
publicly available only in hard copy form. Publicly available docket 
materials are available either electronically in www.regulations.gov or 
in hard copy at the Air and Radiation Docket and Information Center, 
EPA/DC, EPA West, Room 3334, 1301 Constitution Ave. NW., Washington, 
DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday 
through Friday, excluding legal holidays. The telephone number for the 
Public Reading Room is (202) 566-1744, and the telephone number for the 
Air Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: JoNell Iffland, Office of 
Transportation and Air Quality, Assessment and Standards Division 
(ASD), Environmental Protection Agency, 2000 Traverwood Drive, Ann 
Arbor MI 48105; Telephone number: (734) 214-4454; Fax number: (734) 
214-4816; Email address: iffland.jonell@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this action apply to me?

    Entities potentially affected by this rule include gasoline 
refiners and importers, ethanol producers, ethanol denaturant 
producers, butane and pentane producers, gasoline additive 
manufacturers, transmix processors, terminals and fuel distributors, 
light-duty vehicle manufacturers, independent commercial importers, 
alternative fuel converters, and manufacturers and converters of 
vehicles between 8,500 and 14,000 lbs gross vehicle weight rating 
(GVWR).
    Potentially regulated categories include:

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                                                                                      Examples of potentially
           Category                  NAICS\a\ Code              SIC\b\ Code              affected entities
----------------------------------------------------------------------------------------------------------------
Industry.....................  324110..................  2911....................  Petroleum refineries
                                                                                    (including importers).
Industry.....................  325110..................  2869....................  Butane and pentane
                                                                                    manufacturers.
Industry.....................  325193..................  2869....................  Ethyl alcohol manufacturing.
Industry.....................  324110, 211112..........  2911, 1321..............  Ethanol denaturant
                                                                                    manufacturers.
Industry.....................  211112..................  1321....................  Natural gas liquids
                                                                                    extraction and
                                                                                    fractionation.
Industry.....................  325199..................  2869....................  Other basic organic chemical
                                                                                    manufacturing.
Industry.....................  486910..................  4613....................  Natural gas liquids
                                                                                    pipelines, refined petroleum
                                                                                    products pipelines.
Industry.....................  424690..................  5169....................  Chemical and allied products
                                                                                    merchant wholesalers.
Industry.....................  325199..................  2869....................  Manufacturers of gasoline
                                                                                    additives.
Industry.....................  424710..................  5171....................  Petroleum bulk stations and
                                                                                    terminals.
Industry.....................  493190..................  4226....................  Other warehousing and storage-
                                                                                    bulk petroleum storage.
Industry.....................  336111, 336112..........  3711....................  Light-duty vehicle and light-
                                                                                    duty truck manufacturers.
Industry.....................  811111, 811112, 811198..  7538, 7533, 7534........  Independent commercial
                                                                                    importers.
Industry.....................  335312, 336312, 336322,   3621, 3714, 3519, 3599,   Alternative fuel converters.
                                336399, 811198.           7534.
Industry.....................  333618, 336120, 336211,   3699, 3711, 3713, 3714..  On-highway heavy-duty engine
                                336312.                                             & vehicle (>8,500 lbs GVWR)
                                                                                    manufacturers.
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\a\ North American Industry Classification System (NAICS).
\b\ Standard Industrial Classification (SIC).

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. This table lists the types of entities that EPA is now aware 
could potentially be regulated by this action. Other types of entities 
not listed in the table could also be regulated. To determine whether 
your activities are regulated by this action, you should carefully 
examine the applicability criteria in 40 CFR parts 79,

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80, 85, 86, 600, 1036, 1065, and 1066 and the referenced regulations. 
If you have any questions regarding the applicability of this action to 
a particular entity, consult the person listed in the preceding FOR 
FURTHER INFORMATION CONTACT section.

B. Did EPA conduct a peer review before issuing this action?

    This regulatory action was supported by influential scientific 
information. Therefore, EPA conducted peer reviews in accordance with 
OMB's Final Information Quality Bulletin for Peer Review. EPA conducted 
several peer reviews in connection with data supporting the Tier 3 
program, including new research on the effects of fuel properties 
changes (including sulfur effects) on exhaust and evaporative emissions 
of Tier 2 vehicles. The refinery-by-refinery cost model was also peer 
reviewed. The peer review reports are located in the docket for today's 
action, as well as the agency's response to the peer review comments.

Table of Contents

I. Executive Summary and Program Overview
    A. Introduction
    B. Overview of the Tier 3 Program
    1. Major Public Comments and Key Changes From the Proposal
    2. Key Components of the Tier 3 Program
    C. What will the impacts of the standards be?
II. Why is EPA taking this action?
    A. Basis for Action Under the Clean Air Act
    1. Clean Air Act Section 202
    2. Clean Air Act Section 211
    B. Overview of Public Health Impacts of Motor Vehicles and Fuels
    1. Ozone
    2. Particulate Matter
    3. Oxides of Nitrogen and Sulfur
    4. Carbon Monoxide
    5. Mobile Source Air Toxics
    6. Near-Roadway Pollution
    7. Environmental Impacts of Motor Vehicles and Fuels
III. How would this rule reduce emissions and air pollution?
    A. Effects of the Vehicle and Fuel Changes on Mobile Source 
Emissions
    1. How do vehicles produce the emissions addressed in this 
action?
    2. How will the changes to gasoline sulfur content affect 
vehicle emissions?
    B. How will emissions be reduced?
    1. NOX
    2. VOC
    3. CO
    4. Direct PM2.5
    5. Air Toxics
    6. SO2
    7. Greenhouse Gases
    C. How will air pollution be reduced?
    1. Ozone
    2. Particulate Matter
    3. Nitrogen Dioxide
    4. Air Toxics
    5. Visibility
    6. Nitrogen and Sulfur Deposition
    7. Environmental Justice
IV. Vehicle Emissions Program
    A. Tier 3 Tailpipe Emission Standards for Light-Duty Vehicles, 
Light-Duty Trucks, and Medium-Duty Passenger Vehicles
    1. How the Tier 3 Program is harmonized with the California LEV 
III Program
    2. Summary of the Tier 3 FTP and SFTP Tailpipe Standards
    3. FTP Standards
    4. SFTP Standards
    5. Feasibility of the NMOG+NOX and PM Standards
    6. Impact of Gasoline Sulfur Control on the Effectiveness of the 
Vehicle Emission Standards
    7. Other Provisions
    B. Tailpipe Emissions Standards for Heavy-Duty Vehicles
    1. Overview and Scope of Vehicles Regulated
    2. HDV Exhaust Emissions Standards
    3. Supplemental FTP Standards for HDVs
    4. HDV Emissions Averaging, Banking, and Trading
    5. Feasibility of HDV Standards
    6. Other HDV Provisions
    C. Evaporative Emissions Standards
    1. Tier 3 Evaporative Emission Standards
    2. Program Structure and Implementation Flexibilities
    3. Technological Feasibility
    4. Heavy-Duty Gasoline Vehicle (HDGV) Requirements
    5. Evaporative Emission Requirements for FFVs
    6. Test Procedures and Certification Test Fuel
    D. Improvements to In-Use Performance of Fuel Vapor Control 
Systems
    1. Reasons for Adding a Leak Test Standard
    2. Nature, Scope and Timing of Leak Standard
    3. Leak Standard Test Procedure
    4. Certification and Compliance
    a. In-Use Verification Program (IUVP) Requirements for the Leak 
Standard
    E. Onboard Diagnostic System Requirements
    1. Onboard Diagnostic (OBD) System Regulation Changes--Timing
    2. Revisions to EPA OBD Regulatory Requirements
    3. Provisions for Emergency Vehicles
    4. Future Considerations
    F. Emissions Test Fuel
    1. Gasoline Emissions Test Fuel: Ethanol Content and Volatility
    2. Other Gasoline Emissions Test Fuel Specifications
    3. Flexible Fuel Vehicle Exhaust Emissions Test Fuel
    4. Implementation Schedule
    5. Implications of Emission Test Fuel Changes on CAFE Standards, 
GHG Standards, and Fuel Economy Labels
    6. Consideration of Test Fuel for Nonroad Engines and Highway 
Motorcycles
    7. CNG and LPG Emissions Test Fuel Specifications
    G. Small Business Provisions
    1. Lead Time and Relaxed Interim Standards
    2. Assigned Deterioration Factors
    3. Reduced Testing Burden and OBD Requirements
    4. Hardship Relief
    5. Eligibility for the Flexibilities
    H. Compliance Provisions
    1. Exhaust Emission Test Procedures
    2. Reduced Test Burden
    3. Miscellaneous Provisions
    4. Manufacturer In-Use Verification Program (IUVP) Requirements
    V. Fuel Program
    A. Overview
    1. Background
    2. Summary of Final Tier 3 Fuel Program Standards
    B. Annual Average Sulfur Standard
    C. Per-Gallon Sulfur Caps
    1. Standards
    2. Requirements for Gasoline Additives
    D. Averaging, Banking, and Trading Program
    1. How will the ABT Program assist with compliance?
    2. ABT Modeling
    3. Eligibility
    4. Credit Generation and Use
    5. Credit Trading Provisions
    6. ABT Provisions for Small Refiners and Small Volume Refineries
    7. Deficit Carryforward
    E. Additional Program Flexibilities
    1. Regulatory Flexibility Provisions
    2. Provisions for Refiners Facing Hardship Situations
    F. Compliance Provisions
    1. Registration, Reporting, and Recordkeeping Requirements
    2. Sampling and Testing Requirements
    3. Small Refiner Compliance
    4. Small Volume Refinery Compliance
    5. Attest Engagements, Violations, and Penalties
    6. Special Fuel Provisions and Exemptions
    G. Standards for Oxygenates (Including Denatured Fuel Ethanol) 
and Certified Ethanol Denaturants
    H. Standards for Fuel Used in Flexible Fueled Vehicles
    I. Sulfur Standards for Purity Butane and Purity Pentane Streams 
Blended into Gasoline
    J. Standards for CNG and LPG
    K. Refinery Air Permitting Interactions
    1. Proposal
    2. Updated Assessment of Tier 3 Refinery Changes and Permitting 
Implications
    3. Comments and Responses
    L. Refinery Feasibility
    1. Comments Received
    2. Is it feasible for refiners to comply with a 10 ppm average 
sulfur standard?
    3. Can refiners meet the January 1, 2017 start date?
    M. Statutory Authority for Tier 3 Fuel Controls
    1. Section 211(c)(1)(A)
    2. Section 211(c)(1)(B)
    3. Section 211(c)(2)(B)
    4. Section 211(c)(2)(C)
VI. Technical Amendments and Regulatory Streamlining
    A. Fuel Program Amendments
    1. Fuels Program Regulatory Streamlining
    2. Performance-Based Measurement Systems (PBMS)
    3. Downstream Pentane Blending

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    4. Acceptance of Top Tier Deposit Control Test Data
    5. Potential Broader Regulatory Streamlining Through Program 
Restructuring
    B. Engine, Vehicle and Equipment Programs Amendments
    1. Fuel Economy Labeling
    2. Removing Obsolete Regulatory Text
    3. Motorcycle Driving Schedules
    4. Updating Reference Procedures
VII. What are the cost impacts of the rule?
    A. Estimated Costs of the Vehicle Standards
    1. What changes have been made to vehicle program costs since 
proposal?
    2. Summary of Vehicle Program Costs
    B. Estimated Costs of the Fuel Program
    1. Overview
    2. Methodology
    3. Fuel Program Costs
    4. Other Cost Estimates
    C. Summary of Program Costs
VIII. What are the estimated benefits of the rule?
    A. Overview
    B. Quantified Human Health Impacts
    C. Monetized Benefits
    D. What are the limitations of the benefits analysis?
    E. Illustrative Analysis of Estimated Monetized Impacts 
Associated With the Rule in 2018
    IX. Alternatives Analysis
    A. Vehicle Emission Standards
    1. Shorter NMOG+NOX Standard Phase-in
    2. NMOG+NOX Standards Phase-in and Early Tier 3 
Credits
    3. NMOG+NOX Standards
    4. PM Standards
    5. Higher Ethanol Content of Emissions Test Fuel
    B. Fuel Sulfur Standards
    1. Annual Average Sulfur Standard
    2. Refinery Gate Sulfur Cap
    C. Program Start Date
X. Economic Impact Analysis
    A. Introduction
    B. Vehicle Sales Impacts
    C. Impacts on Petroleum Refinery Sector Production
    D. Employment Impacts
    1. Employment Impacts in the Auto Sector
    2. Refinery Employment Impacts
XI. Public Participation
XII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    1. Overview
    2. Background
    3. Reason for Today's Rule
    4. Legal Basis for Agency Action
    5. Summary of Potentially Affected Small Entities
    6. Reporting, Recordkeeping, and Compliance
    7. Related Federal Rules
    8. Steps Taken To Minimize the Economic Impact on Small Entities
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations
    K. Congressional Review Act
XIII. Statutory Provisions and Legal Authority

I. Executive Summary and Program Overview

A. Introduction

    In this action, EPA is finalizing a major program designed to 
reduce air pollution from passenger cars and trucks. This program 
includes new standards for both vehicle emissions and the sulfur 
content of gasoline, considering the vehicle and its fuel as an 
integrated system. We refer to this program as the ``Tier 3'' vehicle 
and fuel standards.
    This rule is part of a comprehensive approach to address the 
impacts of motor vehicles on air quality and public health. Over 149 
million Americans are currently experiencing unhealthy levels of air 
pollution, which are linked with respiratory and cardiovascular 
problems and other adverse health impacts that lead to increased 
medication use, hospital admissions, emergency department visits, and 
premature mortality.\1\ Motor vehicles are a particularly important 
source of exposure to air pollution, especially in urban areas. By 
2018, we project that in many areas that are not attaining health-based 
ambient air quality standards (i.e., ``nonattainment areas''), 
passenger cars and light trucks will contribute 10-25 percent of total 
nitrogen oxides (NOX) emissions, 15-30 percent of total 
volatile organic compound (VOC) emissions, and 5-10 percent of total 
direct particulate matter (PM2.5) emissions.\2\ These 
compounds form ozone, PM, and other air pollutants, whose health and 
environmental effects are described in more detail in Section II. Cars 
and light trucks also continue to be a significant contributor to air 
pollution directly near roads, with gasoline vehicles accounting for 
more than 50 percent of near-road concentrations of some criteria and 
toxic pollutants.\3\ More than 50 million people live, work, or go to 
school in close proximity to high-traffic roadways, and the average 
American spends more than one hour traveling along roads each 
day.4 5 Over 80 percent of daily trips use personal 
vehicles.\6\
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    \1\ The 149 million represents people living in O3, 
PM2.5, PM10, and SO2 nonattainment 
areas. Data come from Summary Nonattainment Area Population Exposure 
Report, current as of December 5, 2013 at: http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket EPA-HQ-OAR-2011-
0135.
    \2\ Mobile source contributions derived from inventories 
developed for this rule. For more information on these inventories 
see the Emissions Inventory Technical Support Document (TSD) for the 
final Tier 3 Rule, Docket ID No. EPA-HQ-OAR-2011-0135.
    \3\ For example, see Fujita, E.M; Campbell, D.E.; Zielinska, B.; 
Arnott, W.P.; Chow, J.C. (2011) Concentrations of Air Toxics in 
Motor Vehicle-Dominated Environments. Health Effects Institute 
Research Report 156. Available at http://www.healtheffects.org.
    \4\ U.S. Census Bureau (2011). Current Housing Reports, Series 
H150/09, American Housing Survey for the United States: 2009. U.S. 
Government Printing Office, Washington, DC. Available at http://www.census.gov/hhes/www/housing/ahs/ahs09/ahs09.html. (Note that 
this survey includes estimates of homes within 300 feet of highways 
with four or more lanes, railroads, and airports.)
    \5\ Drago, R. (2011). Secondary activities in the 2006 American 
Time Use Survey. U.S. Bureau of Labor Statistics Working Paper 446. 
Available at http://www.bls.gov.
    \6\ Santos, A.; McGuckin, N, Yukiko Nakamoto, H.; Gray, D.; 
Liss, S. (2011) Summary of Travel Trends: 2009 National Household 
Travel Survey. Federal Highway Administration report no FHWA-PL-11-
022. Available at http://nhts.ornl.gov/publications.shtml.
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    The standards set forth in this rule will significantly reduce 
levels of multiple air pollutants (such as ambient levels of ozone, PM, 
nitrogen dioxide (NO2), and mobile source air toxics 
(MSATs)) across the country, with immediate benefits from the gasoline 
sulfur control standards starting in 2017. These reductions will help 
state and local agencies in their effort to attain and maintain health-
based National Ambient Air Quality Standards (NAAQS). Few other 
national strategies exist that will deliver the same magnitude of 
multi-pollutant reductions and associated public health protection that 
is projected to result from the Tier 3 standards. Without this action 
to reduce nationwide motor vehicle emissions, areas would have to adopt 
other, less cost-effective measures to reduce emissions from other 
sources under their state or local authority. In the absence of 
additional controls, certain areas would continue to have ambient ozone 
concentrations exceeding the NAAQS in the future. See Section III.C for 
more details.
    The Clean Air Act authorizes EPA to establish emissions standards 
for motor vehicles to address air pollution that may reasonably be 
anticipated to endanger public health or welfare

[[Page 23417]]

(section 202). EPA also has authority to establish fuel controls to 
address such air pollution (section 211). These statutory authorities 
are described in Section II.A.
    The vehicle and gasoline sulfur standards we are finalizing 
represent a ``systems approach'' to reducing vehicle exhaust and 
evaporative emissions by addressing the vehicle and fuel as a system. 
The systems approach enables emission reductions that are both 
technologically feasible and cost-effective beyond what would be 
possible looking at vehicle and fuel standards in isolation. We first 
applied such an approach with our Tier 2 vehicle/gasoline sulfur 
standards (finalized in 2000).\7\ We believe that a similar approach 
for the Tier 3 standards is a cost-effective way to achieve substantial 
additional emissions reductions.
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    \7\ 65 FR 6698 (February 10, 2000).
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    The Tier 3 standards include new light- and heavy-duty vehicle 
emission standards for exhaust emissions of VOC (specifically, non-
methane organic gases, or NMOG), NOX, and PM, as well as new 
evaporative emissions standards. The fully phased-in standards for 
light-duty vehicle, light-duty truck, and medium-duty passenger vehicle 
tailpipe emissions are an 80 percent reduction in fleet average 
NMOG+NOX compared to current standards, and a 70 percent 
reduction in per-vehicle PM standards. The fully phased-in Tier 3 
heavy-duty vehicle tailpipe emissions standards for NMOG+NOX 
and PM are on the order of 60 percent lower than current standards. 
Finally, the fully phased-in evaporative emissions standards represent 
a 50 percent reduction from current standards.
    The vehicle emission standards, combined with the reduction of 
gasoline sulfur content from the current 30 parts per million (ppm) 
average down to a 10 ppm average, will result in dramatic emissions 
reductions for NOX, VOC, direct PM2.5, carbon 
monoxide (CO) and air toxics. For example, in 2030, when Tier 3 
vehicles will make up the majority of the fleet as well as vehicle 
miles traveled, NOX and VOC emissions from on-highway 
vehicles will be reduced by about 21 percent, and CO emissions will be 
reduced by about 24 percent. National emissions of many air toxics from 
on-highway vehicles will also be reduced by 10 to nearly 30 percent. 
Reductions will continue beyond 2030 as more of the fleet is composed 
of vehicles meeting the fully phased-in Tier 3 standards. For example, 
the Tier 3 program will reduce on-highway emissions of NOX 
and VOC nearly 31 percent by 2050, when vehicles meeting the fully 
phased-in Tier 3 standards will comprise almost the entire fleet.
    Gasoline vehicles depend to a great degree on catalytic converters 
to reduce levels of pollutants in their exhaust, including NMOG and 
NOX, as well as PM (specifically, the volatile hydrocarbon 
fraction), CO, and most air toxics. The catalytic converters become 
significantly less efficient when exposed to sulfur. The Tier 2 
rulemaking required refiners to take steps to reduce sulfur levels in 
gasoline by approximately 90 percent, to an average of 30 ppm. As 
discussed in Section IV.A.6, subsequent research provides a compelling 
case that even this level of sulfur not only degrades the emission 
performance of vehicles on the road today, but also inhibits necessary 
further reductions in vehicle emissions performance to reach the Tier 3 
standards. Thus, the 10 ppm average sulfur standard for Tier 3 is 
significant in two ways: it enables vehicles designed to the Tier 3 
tailpipe exhaust standards to meet these standards in-use for the 
duration of their useful life, and it facilitates immediate emission 
reductions from all the vehicles on the road at the time the fuel 
sulfur controls are implemented. EPA is not the first regulatory agency 
to recognize the need for lower-sulfur gasoline. Agencies in Europe and 
Japan have already imposed gasoline sulfur caps of 10 ppm, and the 
State of California is already averaging 10 ppm sulfur with a per 
gallon cap of 20 ppm. Other states are preempted by the Clean Air Act 
from adopting new fuel programs to meet air quality objectives. 
Consequently, they could not receive the air quality benefits of lower 
sulfur gasoline without federal action.
    This action is one aspect of a comprehensive national program 
regulating emissions from motor vehicles. EPA's final rule for reducing 
greenhouse gas (GHG) emissions from light-duty (LD) vehicles starting 
with model year (MY) 2017 (referred to here as the ``2017 LD GHG'' 
standards) is another aspect of this comprehensive program.\8\ The Tier 
3 program addresses interactions with the 2017 LD GHG rule in a manner 
that aligns implementation of the two actions, to achieve significant 
criteria pollutant and GHG emissions reductions while providing 
regulatory certainty and compliance efficiency. As vehicle 
manufacturers introduce new vehicle platforms for compliance with the 
GHG standards, they will be able to design them for compliance with the 
Tier 3 standards at the same time. The Tier 3 standards are also 
closely coordinated with California's Low Emission Vehicle (LEV) III 
program to create a vehicle emissions program that will allow 
automakers to sell the same vehicles in all 50 states. (In December 
2012 EPA approved a waiver of Clean Air Act preemption for the 
California Air Resources Board's (CARB's) LEV III program with 
compliance beginning in 2015. Twelve states adopted the LEV III program 
under Section 177 of the Clean Air Act.\9\) We have worked closely with 
individual vehicle manufacturers and their trade associations, who have 
emphasized the importance of a harmonized national program. Together, 
the Tier 3, 2017 LD GHG, and LEV III standards will provide significant 
reductions in GHGs, criteria pollutants and air toxics from motor 
vehicles while streamlining programs and enabling manufacturers to 
design a single vehicle for nationwide sales, thus reducing their costs 
of compliance. In this way, the Tier 3 program responds to the May 21, 
2010 Presidential Memorandum that requested that EPA develop a 
comprehensive approach toward regulating motor vehicles, including 
consideration of non-GHG emissions standards.\10\
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    \8\ EPA's GHG standards are part of a joint National Program 
with the National Highway Traffic Safety Administration, which also 
set coordinated standards for Corporate Average Fuel Economy (CAFE). 
77 FR 62623 (October 15, 2012).
    \9\ These states include Connecticut, Delaware, Maryland, Maine, 
Massachusetts, New Jersey, New York, Oregon, Pennsylvania, Rhode 
Island, Washington, and Vermont.
    \10\ The Presidential Memorandum is found at: http://www.whitehouse.gov/the-press-office/presidential-memorandum-regarding-fuel-efficiency-standards.
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    As part of the systems approach to this program, we have considered 
the types of fuels on which vehicles will be operating in the future. 
In particular, the renewable fuels mandate that was revised by the 
Energy Independence and Security Act (EISA) and is being implemented 
through the Renewable Fuel Standards program (RFS2) \11\ is resulting 
in the use of significant amounts of ethanol-blended gasoline. We are 
updating the specifications of the emissions test fuel with which 
vehicles demonstrate compliance with emissions standards, in order to 
better reflect the ethanol content and other properties of gasoline 
that is in use today and is expected in future years.
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    \11\ 75 FR 14670 (March 26, 2010).
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    Section I provides an overview of the vehicle and fuel standards we 
are finalizing as well as the impacts of the standards. The public 
health issues and statutory requirements that have prompted this action 
are described in Section II, and our discussion of how

[[Page 23418]]

the Tier 3 standards will reduce emissions and air pollution is 
presented in Section III. Details of the standards and how they will be 
implemented can be found in Sections IV through VI. Sections VII 
through X contain our discussion of the standards' technological 
feasibility and costs, benefits, and economic impacts. Sections XI 
through XIII address public participation, statutory and executive 
orders, and statutory provisions and legal authority under the Clean 
Air Act covered in this rulemaking.
    This final rule is based on extensive public input received in 
response to EPA's Tier 3 proposal. The proposal was signed and posted 
on the EPA Web site on March 29, 2013, and published in the Federal 
Register on May 21, 2013. EPA held two public hearings in Philadelphia 
and Chicago in April 2013. In response to stakeholder requests, EPA 
extended the public comment period to July 1, 2013. We received more 
than 200,000 public comments. A broad range of stakeholders provided 
comments, including state and local governments, auto manufacturers, 
emissions control suppliers, refiners, fuel distributors and others in 
the petroleum industry, renewable fuels providers, environmental 
organizations, consumer groups, labor groups, private citizens, and 
others. Some of the issues raised in comments included lead time and 
the program's start date, the vehicle manufacturers' support for a 50-
state program harmonized with California, the need for and degree of 
gasoline sulfur control (including the level of the sulfur cap), the 
ethanol content of vehicle certification test fuel, and various details 
on the flexibilities and other program design features of both the 
vehicle and fuels standards.

B. Overview of the Tier 3 Program

    In the 14 years since EPA established the Tier 2 Vehicle Program, 
manufacturers of light-duty vehicles and automotive technology 
suppliers have continued to develop a wide range of improved 
technologies capable of reducing vehicle emissions. The California LEV 
II program has been instrumental in the continuous technology 
improvements by requiring year after year reductions in fleet average 
hydrocarbon levels, in addition to requiring the introduction of 
advanced exhaust and evaporative emission controls in partial zero 
emission vehicles (PZEVs). This technological progress has made it 
possible for manufacturers to achieve emission reductions well beyond 
the requirements of the Tier 2 program if gasoline sulfur levels are 
lowered further.
    As a result, in conjunction with lower gasoline sulfur standards, 
we are establishing new Tier 3 standards for exhaust emissions of NMOG, 
NOX, and PM, as well as for evaporative hydrocarbon 
emissions. These vehicle emissions standards will phase in beginning 
with MY 2017. The structure of the Tier 3 standards is very similar to 
that of the existing Tier 2 program. As with the Tier 2 program, the 
standards will apply to all light-duty vehicles (LDVs, or passenger 
cars), light-duty trucks (LDT1s, LDT2s, LDT3s, and LDT4s) and Medium-
Duty Passenger Vehicles (MDPVs). We also are establishing separate but 
closely related standards for heavy-duty vehicles up to 14,000 lbs 
Gross Vehicle Weight Rating (GVWR).\12\ We have concluded that the 
vehicle emissions standards, in conjunction with the reductions in fuel 
sulfur also required by this action, are feasible across the fleet in 
the timeframe provided.
---------------------------------------------------------------------------

    \12\ These heavy-duty vehicles were not included in the Tier 2 
program but were subject to standards in a subsequent rule covering 
the heavy-duty sector (66 FR 5002, January 18, 2001).
---------------------------------------------------------------------------

    Auto manufacturers have stressed the importance of being able to 
design, produce, and sell a single fleet of vehicles in all 50 states 
that complies with both the Tier 3 and California LEV III programs, as 
well as the greenhouse gas (GHG)/Corporate Average Fuel Economy (CAFE) 
programs in the same timeframe. To that end, we worked closely with the 
California Air Resources Board and vehicle manufacturers to align the 
two programs as closely as possible. This consistency among the federal 
and California programs means that manufacturers do not need to design 
unique versions of vehicles with different emission control hardware 
and calibrations for different geographic areas. This allows 
manufacturers to avoid the additional costs of parallel design, 
development, calibration, and manufacturing. We also have designed the 
Tier 3 program to be implemented in the same timeframe as the GHG 
emissions and fuel economy standards for model years 2017-2025. We 
expect that in response to these programs, manufacturers will be 
developing entirely new powertrains for most of their vehicles. Because 
the Tier 3 standards will phase in over the same timeframe, 
manufacturers are in a better position to simultaneously respond to all 
of these requirements.
    Overall, the final Tier 3 program is very similar to the program we 
proposed. As discussed below and throughout this preamble, the program 
phases in over several years--with the primary vehicle emission 
standards starting in Model Year (MY) 2017 (2018 for heavier vehicles) 
and the gasoline sulfur control provisions beginning in 2017.
    As discussed above, we received a large number and wide range of 
comments on the proposed rule. Several comments raise particularly 
significant issues concerning some fundamental components of the Tier 3 
program, including when the vehicle-related and fuel-related 
requirements begin. We briefly discuss these key issues in this 
section, and in more detail later in this preamble. The Summary and 
Analysis of Comments document provides our responses to the comments we 
received; it is located in the docket for this rulemaking and also on 
EPA's Web site at www.epa.gov/otaq/tier3.htm.
1. Major Public Comments and Key Changes From the Proposal
a. Start Date and Lead Time Issues
(1) Gasoline Sulfur Control Program
    Many stakeholders commented on the proposed 2017 start date of the 
Tier 3 program, with state and NGO organizations supporting finalizing 
the standards as proposed. Conversely, refiners, importers, and others 
in the fuel industry commented that they believed the proposed start 
date would not provide a sufficient amount of lead time to meet the 
requirements of the Tier 3 program, and that EPA has historically 
provided at least four years of lead time in previous fuels 
rulemakings. These commenters noted that five years of lead time is 
needed to allow for necessary refinery changes to be made during a 
refinery's normal turnaround/shutdown schedule (these occur every four 
years, on average) and to allow adequate time for the permitting 
process. These commenters also stated that, given the proposed 
flexibility provisions for vehicles, that a 2017 fuel program start 
date was not truly needed to enable the vehicle technology. Further, 
these commenters stated that they believed insufficient lead time would 
drive up the costs for regulated entities as they would need to do 
unscheduled shutdowns to install and/or revamp equipment to meet the 
proposed standards. Lastly, they stated that the uncertainty regarding 
the potential availability of credits would make meeting a 2017 start 
date more challenging.
    As discussed in greater detail in Section V below, we are 
finalizing the proposed start date of January 1, 2017. We understand 
refiners' concerns,

[[Page 23419]]

including their concerns over the necessary capital investments and 
potential off-cycle turnarounds/shutdowns to make refinery 
modifications for Tier 3. In light of these concerns, we are finalizing 
additional flexibilities beyond those already in the proposal and we 
are confident that the program being finalized today addresses these 
concerns. Considering all the flexibilities offered to regulated 
parties, there is, in effect, nearly 6 years of time to comply provided 
for those refineries that may need it. As discussed in Section V.D, we 
are finalizing a credit averaging, banking, and trading (ABT) program 
that will allow for a smooth transition from the Tier 2 to Tier 3 ABT 
programs (including provisions for early credit generation beginning in 
2014). These early credit provisions, coupled with the ability to carry 
over credits from Tier 2 into Tier 3 (an additional flexibility being 
finalized today that was not part of the proposal), will allow for 
early actions to reduce sulfur levels by some refineries to be used to 
delay the need for actions at other refineries until 2020. This 
structure of the ABT program allows refiners and importers the 
flexibility to choose the most economical compliance strategy--
investment in technology, use of credits, or both--for meeting the Tier 
3 average gasoline sulfur standard. In addition, approved small 
refiners and small volume refineries are given an additional three 
years from the January 1, 2017, Tier 3 program start date to comply 
(January 1, 2020).
    We proposed that the Tier 2 ABT program would not only be separate 
from the Tier 3 ABT program, but that it would also end at the start of 
the Tier 3 program in 2017. The implications of this meant that any 
Tier 2 credits generated after 2012 would run the risk of expiring 
before the end of their full five-year life if they were not used 
before January 1, 2017. Commenters requested that EPA consider allowing 
such Tier 2 ``banked'' credits to receive their full five-year life. 
This would eliminate any incentive refiners may have to use these 
credits prior to the end of the Tier 2 program to raise their in-use 
sulfur levels. The ABT program that we are finalizing today enables a 
seamless transition from Tier 2 to Tier 3, including an allowance for 
Tier 2 banked credits to be used for their full five-year life or 
through December 31, 2019, whichever is earlier. Not only does this 
provision effectively provide more lead time and flexibility for 
refiners and importers, but we believe these banked credits will help 
to provide certainty of the availability of credits for refiners and 
importers who may want to rely on them for compliance.
    Finally, as discussed in Section V.E.2, we are also finalizing 
hardship provisions that allow refiners to petition for delayed 
compliance, on a case-by-case basis, for situations of extreme hardship 
or extreme unforeseen circumstances. These provisions, similar to those 
implemented in past fuel rulemakings, provide a safety valve should all 
the other flexibilities provided prove insufficient. As part of these 
hardship provisions, we are finalizing the ability for refiners to 
carry a deficit for up to 3 years, providing them with yet additional 
flexibility during the transition to Tier 3 should it prove necessary.
(2) Vehicle Emission Control Program
    There were no major concerns raised for the proposed MY 2017 start 
date for lighter light-duty vehicles, although commenters from the auto 
manufacturing industry raised concerns about the lead time we proposed 
for heavier light-duty vehicles. Specifically, commenters pointed to 
Clean Air Act section 202(a)(3)(C) that, for vehicles over 6,000 lbs 
GVWR, requires that EPA emission standards provide at least four years 
of lead time and three years of regulatory stability.
    In light of this statutory requirement, in addition to the primary 
declining fleet average standards starting in MY 2018 for heavier 
vehicles, EPA proposed an alternative phase-in schedule for any 
manufacturer that prefers a longer lead time and annual stability for 
these vehicles in lieu of the declining fleet average standards option. 
The commenters stated that the proposed alternative pathway would be 
too difficult to take advantage of in comparison to the primary program 
and thereby failed to comply with the Clean Air Act.
    In considering these comments, EPA also considered that during the 
development of the Tier 3 program and in their comments, the same auto 
industry commenters consistently urged EPA to design the Tier 3 program 
to harmonize with the California LEV III standards as closely and as 
early as possible. As discussed in detail below in Section IV.A, 
extensive data that EPA has generated or received continue to support 
the conclusion that the primary fleet-average standards provide a 
compliance path that is feasible across the industry and that closely 
harmonizes with LEV III. EPA believes that we have reasonably resolved 
these somewhat competing concerns--early harmonization vs. additional 
lead time--by finalizing the primary declining fleet average standards 
as proposed while also finalizing revised alternative phase-in 
compliance schedules (see Section IV.A.2.c). In response to the 
comments on this topic, we have revised the alternative phase-in 
schedules to reduce their associated burden for manufacturers, while 
still maintaining environmental benefits that are equivalent to the 
primary program. We also include provisions in the percent-of-sales 
phase-in alternatives that allow manufacturers to exclude vehicle 
models that begin their 2019 model year production early in 2018, in 
order to provide four years of lead time.
b. Emissions Test Fuel
    In-use gasoline has changed considerably since EPA last revised 
specifications for the test gasoline used in emissions testing of 
light- and heavy-duty vehicles. Perhaps most importantly, gasoline 
containing 10 percent ethanol by volume (E10) has replaced non-
oxygenated gasoline (E0) across the country. As a result, we are 
updating federal emissions test fuel specifications to better match in-
use fuel.
    In the NPRM, EPA proposed that the specified gasoline for emissions 
testing be changed from E0 to E15 as a forward-looking approach. Since 
then, several factors have led EPA to reconsider that approach, 
including minimal proliferation on a national scale of stations 
offering E15 and the complexities that E15 would introduce for long-
term harmonization with California's use of E10 in their LEVIII 
program. We received comments from a broad set of stakeholders 
including the auto and oil industries, states, and NGOs with a general 
consensus that E15 would not be appropriate as the official test fuel 
at this time. Ethanol industry commenters supported E15 certification 
fuel, but provided no timeline by which this blend level would be 
representative of in-use fuel. In light of the comments received and 
EPA's assessment of the current and projected levels of ethanol in 
gasoline in use, we are finalizing E10 as the new emissions test fuel.
    In deciding to finalize E10 test fuel, EPA considered whether to 
change the volatility of the test fuel, typically expressed as pounds 
per square inch (psi) Reid Vapor Pressure (RVP). As discussed in detail 
in Section IV.F, after considering technical and policy implications as 
well as stakeholder comments, we have concluded that the most 
appropriate approach is to maintain an RVP of 9 psi for the E10 
emissions test fuel at this time. EPA considered raising test fuel RVP 
to 10

[[Page 23420]]

psi, but decided to leave it unchanged at 9 psi based on what would 
have been the associated increase in stringency of the Tier 3 
evaporative standard with 10 psi and the loss of regulatory harmony on 
evaporative emissions with California's LEV III program.
    As a result, after reassessing market trends and considering 
comments, EPA concludes that the most appropriate approach is to 
finalize an ethanol content of 10 percent and an RVP of 9 psi for 
emissions test gasoline. We will continue to monitor ethanol trends in 
the gasoline market, as discussed later in this preamble.
c. Gasoline Sulfur Caps
    As described in more detail in Section V.C. we proposed two options 
for the Tier 3 per-gallon sulfur caps--maintaining the Tier 2 refinery 
gate sulfur cap of 80 ppm (with a 95 ppm downstream sulfur cap), and 
lowering to a 50 ppm refinery gate sulfur cap beginning January 1, 2020 
(with a 65 ppm downstream cap). We received comments supporting lower 
per-gallon caps which noted potential environmental benefits, greater 
certainty that vehicles would see lower and more uniform gasoline 
sulfur levels, and the ability to enable new vehicle technologies 
requiring very low sulfur levels. Conversely, comments received in 
support of maintaining the Tier 2 per-gallon caps cited concerns on 
cost, flexibility for turnarounds/unplanned shutdowns (due to refinery 
fires, natural disasters, etc.), and gasoline supply and/or price 
impacts.
    Analysis performed since the time of the proposal found that a 
lower refinery gate cap would likely result in higher costs to the 
fuels industry and a decreased ability to handle off-spec product 
(potentially impacting gasoline supply and pricing), without any 
significant increase in the nationwide emissions reductions provided by 
the Tier 3 program. Thus, in today's action we are retaining the Tier 2 
per-gallon sulfur caps. The 80 ppm refinery gate cap will provide 
refiners needed flexibility in allowing for naturally-occurring fuel 
batch variability, as well as more certainty that they will be able to 
continue producing and distributing gasoline during turnarounds/upsets 
to avoid a total shutdown. It will also provide more certainty for 
transmix processors, additive manufacturers, and other downstream 
parties in producing gasoline.
    However, we do understand commenters' concerns that retaining the 
Tier 2 sulfur caps might create regional differences in the benefits of 
the Tier 3 program. Therefore we will continue to monitor in-use sulfur 
levels and their impact on vehicle emissions to ascertain whether a 
future reduction in the per-gallon cap may be necessary.
d. Effect of Gasoline Sulfur on Tier 3 Vehicle Emissions
    The need for and level of gasoline sulfur control was a key issue 
raised in public comments. The petroleum industry raised concerns that 
there was insufficient basis for the proposed 10 ppm average sulfur 
level, while auto manufacturers and emissions control equipment 
manufacturers stressed that the feasibility of the Tier 3 vehicle 
standards was dependent on near-zero gasoline sulfur levels. This issue 
is discussed in detail below in Section IV.A.6. In sum, EPA believes 
that the range of studies conducted by EPA and others in recent years, 
along with the comments submitted by the auto industry and emissions 
control manufacturers during the comment period and more recently, 
strongly reinforce our conclusion that the impact of gasoline sulfur 
poisoning on exhaust catalyst performance is significant.
    Sulfur is a well-known catalyst poison. The nature of sulfur's 
interactions with active catalytic materials is complex and varies with 
catalyst composition, exhaust gas composition, and exhaust temperature. 
Thus, even if a manufacturer were able to certify a new vehicle to the 
new stringent standards, the manufacturer's ability to maintain the 
emission performance of that vehicle in-use is greatly jeopardized if 
the vehicle is being operated on gasoline sulfur levels greater than 10 
ppm. In fact, due to the variation in actual vehicle operation, any 
amount of gasoline sulfur will deteriorate catalyst efficiency. Vehicle 
manufacturers and suppliers, both individually and through their trade 
associations, stressed the need for gasoline sulfur to be reduced to 
near zero levels in order for them to meet the proposed standards. 
However, we believe that a 10 ppm average sulfur level is sufficiently 
low to enable compliance with the Tier 3 vehicle standards, and as 
described below and in Section V, reducing sulfur levels further would 
cause sulfur control costs to quickly escalate.
    Taken together, this information provides a compelling argument 
that the fleetwide Tier 3 vehicle standards are achievable only with a 
reduction of gasoline sulfur content from the current 30 ppm average 
down to a 10 ppm average.
e. SFTP (US06) PM Standard for Light-Duty Vehicles
    The final Tier 3 vehicle standards are largely unchanged from their 
proposed levels. One change from the proposal is the PM emissions 
standards as measured on the US06 test cycle. The US06 cycle is part of 
the composite Supplemental Federal Test Procedure (SFTP) and simulates 
aggressive driving. The US06 PM standards are part of the suite of Tier 
3 tailpipe standards that limit emissions under a wide range of common 
vehicle driving conditions. Newer emissions test data presented in the 
NPRM, as well as more recent additional test data submitted in public 
comments, show that a numerically lower US06 PM standard is feasible 
and appropriately reflects the actual emissions performance achieved by 
many vehicles in the fleet today while preventing increased emissions 
in the future.
    Taken together, the test results clearly show that most current 
light-duty vehicles--regardless of engine technology, emission control 
strategy, or vehicle size--are performing at much lower US06 emission 
levels than previously documented. Based on these newer data, we 
believe that it is appropriate to finalize a numerically lower US06 PM 
emission standard for LDVs, LDTs, and MDPVs, and to set a single 
standard for both lighter and heavier vehicles in this vehicle segment. 
In general, the final US06 PM standard for these vehicles begins to 
phase in at a level of 10 mg/mi in MYs 2017 and 2018, stepping down to 
a level of 6 mg/mi in MY2019. See Section IV.A.4.b for additional 
discussion of the US06 standards and how they will phase in.
2. Key Components of the Tier 3 Program
a. Tailpipe Standards for Light-Duty Vehicle, Light-Duty Truck, and 
Medium-Duty Passenger Vehicle Tailpipe Emissions
    We are establishing a comprehensive program that includes new 
fleet-average standards for the sum of NMOG and NOX tailpipe 
emissions (presented as NMOG+NOX) as well as new per-vehicle 
standards for PM.\13\ These standards, when applied in conjunction with 
reduced gasoline sulfur content, will result in very significant 
improvements in vehicle emissions from the levels of the Tier 2 
program. For these pollutants, the standards are measured on test 
procedures that represent a range of

[[Page 23421]]

vehicle operation, including the Federal Test Procedure (or FTP, 
simulating typical driving) and the Supplemental Federal Test Procedure 
(or SFTP, a composite test simulating higher ambient temperatures, 
higher vehicle speeds, and quicker accelerations). In addition to the 
standards, we are extending the regulatory useful life period during 
which the standards apply (see Section IV.A.7.b below) and making test 
fuel more representative of expected real-world fuel (see Section 
I.B.2.e below). The final standards are in most cases identical to 
those of California's LEVIII program, which provides the 50-state 
harmonization strongly supported by the auto industry.
---------------------------------------------------------------------------

    \13\ A discussion of the reasons for combining NMOG and 
NOX for this purpose is in Section IV.A.3.a below.
---------------------------------------------------------------------------

    As proposed, the new Tier 3 FTP and SFTP NMOG+NOX 
standards are fleet-average standards, meaning that a manufacturer 
calculates the average emissions of the vehicles it sells in each model 
year and compares that average to the applicable standard for that 
model year. The manufacturer certifies each of its vehicles to a per-
vehicle ``bin'' standard (see Section IV.A.2) and sales-weights these 
values to calculate its fleet-average NMOG+NOX emissions for 
each model year. Table I-1 summarizes the fleet average standards for 
NMOG+NOX evaluated over the FTP. The standards for light-
duty vehicles begin in MY 2017 at a level representing a 46 percent 
reduction from the Tier 2 requirements. For the light-duty fleet over 
6000 lbs GVWR, and MDPVs, the standards apply beginning in MY 2018. As 
shown, these fleet-average standards decline during the first several 
years of the program, becoming increasingly stringent until ultimately 
reaching an 81 percent reduction when the transition is complete. The 
FTP NMOG+NOX program includes two separate sets of declining 
fleet-average standards, with LDVs and small light trucks in one 
grouping and heavier light trucks and MDPVs in a second grouping, that 
converge at 30 milligrams per mile (mg/mi) in MY 2025 and later. As 
mentioned above, we are also providing alternative percent phase-in 
schedules for this and the other light-duty standards.

                                        Table I-1--Tier 3 LDV, LDT, and MDPV Fleet Average FTP NMOG+NOX Standards
                                                                         [mg/mi]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                   Model year
                                                      --------------------------------------------------------------------------------------------------
                                                                                                                                                2025 and
                                                        2017 \a\     2018       2019       2020       2021       2022       2023       2024      later
--------------------------------------------------------------------------------------------------------------------------------------------------------
LDV/LDT1 \b\.........................................         86         79         72         65         58         51         44         37         30
LDT2,3,4 and MDPV....................................        101         92         83         74         65         56         47         38         30
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ For LDV and LDTs above 6000 lbs GVWR and MDPVs, the fleet average standards apply beginning in MY 2018.
\b\ These standards apply for a 150,000 mile useful life. Manufacturers can choose to certify some or all of their LDVs and LDT1s to a useful life of
  120,000 miles. If a vehicle model is certified to the shorter useful life, a proportionally lower numerical fleet-average standard applies, calculated
  by multiplying the respective 150,000 mile standard by 0.85 and rounding to the nearest mg. See Section IV.A.7.c.

    Similarly, as proposed, the NMOG+NOX standards measured 
over the SFTP are fleet-average standards, declining from MY 2017 until 
MY 2025, as shown in Table I-2. In this case, the same standards apply 
to both lighter and heavier vehicles in the light-duty fleet. In MY 
2025, the SFTP NMOG+NOX standard reaches its final fleet 
average level of 50 mg/mi.

                                       Table I-2--Tier 3 LDV, LDT, and MDPV Fleet Average SFTP NMOG+NOX Standards
                                                                         [mg/mi]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                              Model year
                                             -----------------------------------------------------------------------------------------------------------
                                                                                                                                               2025 and
                                               2017 \a\      2018        2019        2020        2021        2022        2023        2024        later
--------------------------------------------------------------------------------------------------------------------------------------------------------
NMOG + NOX..................................        103          97          90          83          77          70          63          57          50
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ For LDVs and LDTs above 6000 lbs GVWR and MDPVs, the fleet average standards apply beginning in MY 2018.

    As proposed, manufacturers can also earn credits if their fleet 
average NMOG+NOX performance is better than the applicable 
standard in any model year. Credits that have been previously banked or 
obtained from other manufacturers can be used, or credits can be traded 
to other manufacturers. Manufacturers would also be allowed to carry 
forward deficits in their credit balance. (See Sections IV.A.7.a and 
IV.A.7.m).
    We are also establishing PM standards as part of the Tier 3 
program, for both the FTP and US06 cycles (as described above, US06 is 
a component of the SFTP test). Research has demonstrated that the level 
of PM from gasoline light-duty vehicles is more significant than 
previously thought.\14\ Although many vehicles today are performing at 
or near the levels of the new standards, the data indicate that 
improvements, especially in high-load fuel control and in the 
durability of engine components, are possible.
---------------------------------------------------------------------------

    \14\ Nam, E.; Fulper, C.; Warila, J.; Somers, J.; Michaels, H.; 
Baldauf, R.; Rykowski, R.; and Scarbro, C. (2008). Analysis of 
Particulate Matter Emissions from Light-Duty Gasoline Vehicles in 
Kansas City, EPA420-R-08-010. Assessment and Standards Division 
Office of Transportation and Air Quality U.S. Environmental 
Protection Agency Ann Arbor, MI, April 2008.
---------------------------------------------------------------------------

    Under typical driving, as simulated by the FTP, the PM emissions of 
most current-technology gasoline vehicles are fairly low at 
certification and in use, well below the Tier 2 PM standards. At the 
same time we see considerable variation in PM emissions among vehicles 
of various makes, models, and designs. As a result, as proposed, we are 
setting the new FTP PM standard at a level that will ensure that all 
new vehicles perform at the level already being achieved by well-
designed Tier 2 vehicles. The PM standards apply to each vehicle 
separately (i.e., not as a fleet average). Also, in contrast to the 
declining NMOG+NOX standards, the

[[Page 23422]]

PM standard on the FTP for certification testing is 3 mg/mi for all 
vehicles and for all model years. As for the NMOG+NOX 
standards, for vehicles over 6000 lbs GVWR, the FTP PM standard applies 
beginning in MY 2018. Manufacturers can phase in their vehicle models 
as a percent of U.S. sales through MY 2022. Most vehicles are already 
performing at this stringent PM level, and the primary intent of the 
standard is to bring all light-duty vehicles to the typical level of PM 
performance being demonstrated by many of today's vehicles.
    As proposed, the Tier 3 program also includes a temporary in-use 
FTP PM standard of 6 mg/mi for the testing of in-use vehicles that 
applies during the percent phase-in period only. This in-use standard 
will address the in-use variability and durability uncertainties that 
accompany the introduction of new technologies. Table I-3 presents the 
FTP certification and in-use PM standards and the phase-in percentages.

                                 Table I-3--Phase-In for Tier 3 FTP PM Standards
----------------------------------------------------------------------------------------------------------------
                                                                                                        2022 and
                                                 2017 \a\     2018       2019       2020       2021      later
----------------------------------------------------------------------------------------------------------------
Phase-In (percent of U.S. sales)..............     \b\ 20         20         40         70        100        100
Certification Standard (mg/mi)................          3          3          3          3          3          3
In-Use Standard (mg/mi).......................          6          6          6          6          6          3
----------------------------------------------------------------------------------------------------------------
\a\ For LDVs and LDTs above 6000 lbs GVWR and MDPVs, the FTP PM standards apply beginning in MY 2018.
\b\ Manufacturers comply in MY 2017 with 20 percent of their LDV and LDT fleet under 6,000 lbs GVWR, or
  alternatively with 10 percent of their total LDV, LDT, and MDPV fleet.

    Finally, as discussed in Section I.B.1.e above, the Tier 3 program 
includes PM standards evaluated over the US06 driving cycle (the US06 
is one part of the SFTP procedure) of 10 mg/mi through MY 2018 and of 6 
mg/mi for 2019 and later model years, for light-duty vehicles. As in 
the case of the FTP PM standards, the intent of the US06 PM standard is 
to bring the emission performance of all vehicles to that already being 
demonstrated by many vehicles in the current light-duty fleet.
b. Heavy-Duty Vehicle Tailpipe Emissions Standards
    As discussed in detail in Section IV.B, we are setting Tier 3 
exhaust emissions standards for complete heavy-duty vehicles (HDVs) 
between 8,501 and 14,000 lbs GVWR. Vehicles in this GVWR range are 
often referred to as Class 2b (8,501-10,000 lbs) and Class 3 (10,001-
14,000 lbs) vehicles, and are typically heavy-duty pickup trucks and 
work or shuttle vans. Most are built by companies with even larger 
light-duty truck markets, and as such they frequently share major 
design characteristics and emissions control technologies with their 
LDT counterparts. However, in contrast to the largely gasoline-fueled 
LDT fleet, roughly half of the heavy-duty pickup and van fleet in the 
U.S. is diesel-fueled. This is an important consideration in setting 
emissions standards, as diesel engine emissions control strategies 
differ from those of gasoline engines.
    As proposed, the key elements of the Tier 3 program for HDVs 
parallel those being adopted for passenger cars and LDTs, with 
adjustments in standard levels, emission test requirements, and 
implementation schedules appropriate to this sector. These key elements 
include combined NMOG+NOX declining fleet average standards, 
a phase-in of PM standards, adoption of a new emissions test fuel for 
gasoline-fueled vehicles, extension of the regulatory useful life to 
150,000 miles or 15 years (whichever occurs first), and a first-ever 
requirement for HDVs to meet standards over an SFTP drive cycle that 
addresses real-world driving modes not well-represented by the FTP 
cycles.
    We are adopting the Class 2b and Class 3 fleet average 
NMOG+NOX standards shown in Table I-4, as proposed. The 
standards become more stringent in successive model years from 2018 to 
2022, with voluntary standards made available in 2016 and 2017, all of 
which are set at levels that match those of California's LEV III 
program for these classes of vehicles. Each covered HDV sold by a 
manufacturer in each model year contributes to this fleet average based 
on the mg/mi NMOG+NOX standard level of the ``bin'' declared 
for it by the manufacturer, who chooses from a set of seven discrete 
Tier 3 bins specified in the regulations. These bin standards then 
become the compliance standards for the vehicle over its useful life, 
with some adjustment provided for in-use testing in the early model 
years of the program.
    As proposed, manufacturers can also earn credits for fleet average 
NMOG+NOX levels below the standard in any model year. Tier 3 
credits that were previously banked, obtained from other manufacturers, 
or transferred across the Class 2b/Class 3 categories can be used to 
help demonstrate compliance. Unused credits expire after 5 model years. 
Manufacturers will also be allowed to carry forward deficits in their 
credit balance for up to 3 model years.

                                               Table I-4--Tier 3 HDV Fleet Average FTP NMOG+NOX Standards
                                                                         [mg/mi]
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Voluntary
                                                                   Required program
--------------------------------------------------------------------------------------------------------------------------------------------------------
Model Year....................................       2016       2017       2018       2019       2020       2021  2022 and later.
Class 2b......................................        333        310        278        253        228        203  178.
Class 3.......................................        548        508        451        400        349        298  247.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We are adopting the proposed FTP PM standards of 8 mg/mi and 10 mg/
mi for Class 2b and Class 3 HDVs, respectively, phasing in as an 
increasing percentage of a manufacturer's sales per year. We are 
adopting the same phase-in schedule as for the light-duty sector during 
model years 2018-2019-2020-2021: 20-40-70-100 percent, respectively, 
and a more flexible but equivalent alternative PM phase-in is also 
being adopted. Tier 3 HDVs will

[[Page 23423]]

also be subject to CO and formaldehyde exhaust emissions standards that 
are more stringent than the existing standards.
    Finally, we are setting first-ever nationwide SFTP standards for 
HDVs to ensure a robust overall control program that precludes high 
off-FTP cycle emissions by having vehicle designers consider them in 
their choice of compliance strategies. As for light-duty vehicles, we 
are requiring that SFTP compliance be based on a weighted composite of 
measured emissions from testing over the FTP cycle, the SC03 cycle, and 
an aggressive driving cycle, with the latter tailored to various HDV 
sub-categories: the US06 cycle for most HDVs, the highway portion of 
the US06 cycle for low power-to-weight Class 2b HDVs, and the LA-92 (or 
``Unified'') cycle for Class 3 HDVs. The SFTP standards are the same as 
those adopted for California LEV III vehicles, and apply to 
NMOG+NOX, PM, and CO emissions.
    The HDV program outlined above and described in detail in Section 
IV.B is substantially what we proposed. Commenters generally supported 
the scope, stringency, and implementation phase-in of this program. 
However, some industry commenters requested changes to some specific 
provisions of the proposal, and the program we are adopting reflects 
improvements we have made in response. These are: (1) A limited 
allowance for engine certification of Class 3 complete diesel vehicles 
to avoid a potential need for dual chassis- and engine-based 
certification and to better harmonize with LEV III, (2) relaxed interim 
in-use testing standards to facilitate a smooth transition to the Tier 
3 standards and to better harmonize with LEV III, (3) adoption of 
combined NMOG+NOX standards for the two highest (interim) 
bins, with a restriction placed on NOX levels in 
certification testing, to enhance the utility of these bins and to 
better harmonize with LEV III, and (4) a provision in the percent-of-
sales phase-in alternative to allow manufacturers to exclude vehicle 
models that begin their 2019 model year production early in 2018, in 
order to provide four years of lead time. Commenters also requested 
relaxed standards for testing at high altitudes and changes to the 
credits program structure for generation of early credits and use of 
LEV III-based ``vehicle emission credits'', but we did not adopt these 
for reasons explained in Section IV.B.
    Overall, we expect the Tier 3 program we are adopting for HDVs to 
result in substantial reductions in harmful emissions from this large 
fleet of work trucks and vans. The fully-phased in Tier 3 standards 
levels for NMOG+NOX and PM are on the order of 60 percent 
lower than the current standards that took full effect in the 2009 
model year.
c. Evaporative Emission Standards
    Gasoline vapor emissions from vehicle fuel systems occur when a 
vehicle is in operation, when it is parked, and when it is being 
refueled. These evaporative emissions, which occur on a daily basis 
from gasoline-powered vehicles, are primarily functions of temperature, 
fuel vapor pressure, and activity. EPA first instituted evaporative 
emission standards in the early 1970s to address emissions when 
vehicles are parked after being driven. These are commonly referred to 
as hot soak plus diurnal emissions. Over the subsequent years the test 
procedures have been modified and improved and the standards have 
become more numerically stringent. We have addressed emissions which 
arose from new fuel system designs by putting in place new requirements 
such as running loss emission standards and test procedure provisions 
to address permeation emissions. Subsequently standards were put in 
place to control refueling emissions from all classes of gasoline-
powered motor vehicles up to 10,000 lbs GVWR. Evaporative and refueling 
emission control systems have been in place for most of these vehicles 
for many years. These controls have led to significant reductions, but 
evaporative and refueling emissions still constitute 30-40 percent of 
the summer on-highway mobile source hydrocarbon inventory. These fuel 
vapor emissions are ozone and PM precursors, and also contain air 
toxics such as benzene.
    To control evaporative emissions, EPA is establishing more 
stringent standards that will require covered vehicles to have 
essentially zero fuel vapor emissions in use. These include more 
stringent evaporative emissions standards, new test procedures, and a 
new fuel/evaporative system leak emission standard. The program also 
includes refueling emission standards for all complete heavy-duty 
gasoline vehicles (HDGVs) over 10,000 lbs GVWR. EPA is including phase-
in flexibilities as well as credit and allowance programs. The 
standards, harmonized with California's ``zero evap'' standards, are 
designed to allow for a use of common technology in vehicle models sold 
throughout the U.S. The level of the standard remains above zero to 
account for nonfuel background emissions from the vehicle hardware.
    Requirements to meet the Tier 3 evaporative emission regulations 
phase in over a six model year period. We are finalizing three options 
for the 2017 model year, but after that the sales percentage 
requirements are 60 percent for MYs 2018 and 2019, 80 percent for model 
years 2020 and 2021, and 100 percent for model years 2022 and later. In 
Table I-5 we present the Tier 3 evaporative hot soak plus diurnal 
emission standards by vehicle class. The standards are approximately a 
50 percent reduction from the existing standards. To enhance 
flexibility and reduce costs, EPA is finalizing provisions that allow 
manufacturers to generate allowances through early certifications 
(basically before the 2017 model year) and to demonstrate compliance 
using averaging concepts. Manufacturers may comply on average within 
each of the four vehicle categories, but not across these categories. 
EPA is not making any changes to the existing light-duty running loss 
or refueling emission standards, with the exception of the 
certification test fuel requirement discussed in Section I.B.2 below.

            Table I-5--Tier 3 Evaporative Emission Standards
                                [g/test]
------------------------------------------------------------------------
                                                    Highest hot soak +
                                                   diurnal level  (over
                 Vehicle class                    both 2-day and  3-day
                                                      diurnal tests)
------------------------------------------------------------------------
LDV, LDT1......................................                    0.300
LDT2...........................................                    0.400
LDT3, LDT4, MDPV...............................                    0.500
HDGVs..........................................                    0.600
------------------------------------------------------------------------

    Flexible Fuel Vehicles (FFVs) must meet the same evaporative 
emission standards as non-FFVs using Tier 3 emissions certification 
test fuel. However, FFVs must meet the refueling emission standards 
using 10 psi RVP fuel to account for emissions resulting from 
commingling with non-E85 blends that may be in the vehicle's fuel tank.
    EPA is establishing the canister bleed emission test procedure and 
emission standard to help ensure fuel vapor emissions are eliminated. 
Under this provision, manufacturers are required to measure diurnal 
emissions over the 2-day diurnal test procedure from just the fuel tank 
and the evaporative emission canister and comply with a 0.020 gram per 
test (g/test) standard for all LDVs, LDTs, and MDPVs, without 
averaging. The corresponding canister bleed test standard for HDGVs is 
0.030 g/test. The Tier 3 evaporative emission standards will be phased 
in over a period of six model years between MY 2017 and MY

[[Page 23424]]

2022, with the leak test phasing in beginning in 2018.
    Data from in-use evaporative emissions testing indicates that vapor 
leaks from vehicle fuel/evaporative systems are found in the fleet and 
that even very small leaks have the potential to make significant 
contributions to the mobile source VOC inventory. To help address this 
issue, we are also adding a new standard and test procedure to control 
vapor leaks from vehicle fuel and vapor control systems. The standard 
will prohibit leaks with a cumulative equivalent diameter of 0.02 
inches or greater. We are adding this simple and inexpensive test and 
emission standard to help ensure vehicles maintain zero fuel vapor 
emissions over their full useful life. New LDV, LDT, MDPV, and HDGV 
equal to or less than 14.000 lbs GVWR meeting the Tier 3 evaporative 
emission regulations are also required to meet the leak standard 
beginning in the 2018 model year. Manufacturers must comply with the 
leak standard phase-in on the same percentage of sales schedule as that 
for the Tier 3 evaporative emission standards. Manufacturers will 
comply with the leak emission standard during certification and in use. 
The leak emission standard does not apply to HDGVs above 14,000 lbs 
GVWR.
    EPA is also establishing new refueling emission control 
requirements for all complete HDGVs equal to or less than 14,000 lbs 
GVWR (i.e., Class 2b/3 HDGVs), starting in the 2018 model year, and for 
all larger complete HDGVs by the 2022 model year. The existing 
refueling emission control requirements apply to complete Class 2b 
HDGVs, and EPA is extending those requirements to other complete HDGVs, 
since the fuel and evaporative control systems on these vehicles are 
very similar to those on their lighter-weight Class 2b counterparts.
d. Onboard Diagnostic Systems (OBD)
    EPA and CARB both have OBD regulations applicable to the vehicle 
classes covered by the Tier 3 emission standards. In the past the 
requirements have been very similar, so most manufacturers have met 
CARB OBD requirements and, as permitted in our regulations, EPA has 
generally accepted compliance with CARB's OBD requirements as 
satisfying EPA's OBD requirements. Over the past several years CARB has 
upgraded its requirements to help improve the effectiveness of OBD in 
ensuring good in-use exhaust and evaporative system emissions 
performance. We have reviewed these provisions and agree with CARB that 
these revisions will help to improve in-use emissions performance, 
while at the same time harmonizing with the CARB program. Toward that 
end, we are adopting and incorporating by reference the current CARB 
OBD regulations, effective for the 2017 MY, with a few minor 
differences including phase-in flexibility provisions and specific 
additions to enhance the implementation of the leak standard. EPA is 
retaining the provision that certifying with CARB's program would 
permit manufacturers to seek a separate EPA certificate on that basis.
e. Emissions Test Fuel
    As described above, after reassessing market trends and considering 
comments, EPA is finalizing E10 as the ethanol blend level in emissions 
test gasoline for Tier 3 light-duty and heavy-duty gasoline vehicles. 
We will continue to monitor the in-use gasoline supply and based on 
such review may initiate rulemaking action to revise the specifications 
for emissions test fuel to include a higher ethanol blend level. EPA is 
also making additional changes that are consistent with CARB's LEV III 
emissions test fuel specifications, including new specifications for 
octane, distillation temperatures, aromatics, olefins, sulfur and 
benzene. (See Section IV.F below for a detailed discussion of all the 
revised emission test fuel parameters.)
    As discussed in Sections IV.A.7.d (tailpipe emission testing) and 
IV.C.5.b (evaporative emission testing), we are requiring certification 
of all Tier 3 light-duty and chassis-certified heavy-duty gasoline 
vehicles on federal E10 test fuel. The new test fuel specifications 
will apply to new vehicle certification, assembly line, and in-use 
testing.
    With a change in the ethanol content of the test fuel, EPA also 
needed to consider whether a change is warranted in the volatility of 
the test fuel, typically expressed as pounds per square inch (psi) Reid 
Vapor Pressure (RVP). As discussed in detail in Section IV.F below, 
after considering several technical and policy implications as well as 
stakeholder comments, EPA has concluded that the most appropriate 
approach is to maintain an RVP of 9 psi for the E10 certification fuel 
at this time.
    In addition to finalizing a new E10 emissions test fuel, we are 
also finalizing detailed specifications for the E85 emissions test fuel 
used for flexible fuel vehicle (FFV) certification, as discussed in 
Section IV.F.3.\15\ This will resolve uncertainty and confusion in the 
certification of FFVs designed to operate on ethanol levels up to 83 
percent. Furthermore, we allow vehicle manufacturers to request 
approval for an alternative certification fuel such as a high-octane 30 
percent ethanol by volume blend (E30) for vehicles that may be 
optimized for such fuel.
---------------------------------------------------------------------------

    \15\ Flexible fuel vehicles are currently required to meet 
emissions certification requirements using both E0 and E85 test 
fuels. However, there were no detailed regulatory specifications 
regarding the composition of E85 test fuels before those finalized 
today.
---------------------------------------------------------------------------

f. Fuel Standards
    Under the Tier 3 fuel program, gasoline must contain no more than 
10 ppm sulfur on an annual average basis beginning January 1, 2017. 
Similar to the Tier 2 gasoline program, the Tier 3 program will apply 
to gasoline in the U.S. and the U.S. territories of Puerto Rico and the 
Virgin Islands, excluding California. The program will result in 
gasoline that contains, on average, two-thirds less sulfur than it does 
today. In addition, following discussions with numerous refiners and 
other segments of the fuel market (e.g., pipelines, terminals, 
marketers, ethanol industry representatives, transmix processors, 
additive manufacturers, etc.), the Tier 3 fuel program contains 
considerable flexibility to ease both initial and long-term 
implementation of the program. The program that we are finalizing today 
includes an averaging, banking, and trading (ABT) program that allows 
refiners and importers to spread out their investments over nearly a 6-
year period through the use of an early credit program and then rely on 
ongoing nationwide averaging to meet the 10 ppm sulfur standard. In 
addition there is a three-year delay for small refiners and ``small 
volume refineries''. As a result of the early credit program, we 
anticipate considerable reductions in gasoline sulfur levels prior to 
2017, with a complete transition to the 10 ppm average occurring by 
January 1, 2020. For more information on the gasoline sulfur program 
flexibilities, refer to Section V.E.
    Under today's Tier 3 gasoline sulfur program, we are maintaining 
the current 80 ppm refinery gate and 95 ppm downstream per-gallon caps. 
We also evaluated and sought comment on the potential of lowering the 
per-gallon caps. While there are advantages and disadvantages with each 
of the sulfur cap options that we proposed, we believe that retaining 
the current Tier 2 sulfur caps is prudent at this time, as explained in 
more detail in Section V.C. Further, the stringency of the 10 ppm 
annual average standard will result in reduced gasoline sulfur levels 
nationwide. Today's program requires

[[Page 23425]]

that manufacturers of gasoline additives that are used downstream of 
the refinery at less than 1 volume percent must limit the sulfur 
contribution to the finished gasoline from the use of their additive to 
less than 3 ppm when the additive is used at the maximum recommended 
treatment rate (see Section V.C.2). This requirement will preclude the 
unnecessary use of high sulfur content additives in gasoline.
    The vehicle emissions standards finalized today are fuel-neutral 
(i.e., they are applicable regardless of the type of fuel that the 
vehicle is designed to use). There currently are no sulfur standards 
for the fuel used in compressed natural gas (CNG) and liquid propane 
gas (LPG) vehicles. We requested comment on whether it is necessary for 
EPA to establish sulfur standards for CNG and LPG to enable them 
meeting more stringent vehicle emissions standards. EPA is deferring 
finalizing in-use sulfur requirements for CNG/LPG in this final rule to 
provide additional time to work with stakeholders to collect data on 
current CNG/LPG sulfur content, to determine whether additional control 
of in-use CNG/LPG sulfur content is needed, and to evaluate the 
feasibility and costs associated with potential additional sulfur 
controls (see Section V.J). Given that the information provided 
suggests that CNG/LPG sulfur levels tend to be low already, the vehicle 
emissions standards finalized today will apply to CNG/LPG vehicles in 
addition to vehicles fueled on gasoline, diesel fuel, or any other 
fuel. The sulfur content of highway diesel fuel is already required to 
meet a 15 ppm sulfur cap, which is sufficient for diesel fuel vehicles 
to meet the Tier 3 emissions standards.
    As the number of flex-fuel vehicles (FFVs) in the in-use fleet 
increases, it is becoming increasingly important that all fuels used in 
FFVs, not just gasoline, meet fuel quality standards. A lack of clarity 
regarding the standards that apply to fuels used in FFVs could also act 
to impede the further expansion of ethanol blended fuels with 
concentrations greater than 15 volume percent, which is important to 
satisfying the requirements of the RFS2 program. Hence, we sought 
comment on appropriate regulatory mechanisms to implement in-use 
quality standards for E51-83 and E16-50 in the Tier 3 proposal. 
Additional work is needed on some issues that could not be accommodated 
within the timeline for this Tier 3 final rule. Therefore, we are 
choosing not to finalize these provisions at this time. We intend to 
finalize in-use fuel quality standards for E51-83 and perhaps E16-50 as 
well in a follow-up final rule.
g. Regulatory Streamlining and Technical Amendments
    This action also includes a number of items to help streamline the 
in-use fuels regulations at 40 CFR parts 79 and 80. The majority of 
these items involve clarifying vague or inconsistent language, removal 
or updating of outdated provisions, and decreasing in frequency and/or 
volume of reporting burden where data are no longer needed or are 
redundant with other EPA fuels programs. In general, we believe that 
these changes will reduce the burden on industry and allow the 
standards and resulting environmental benefits to be achieved as early 
as possible with no expected loss in environmental control. In some 
cases, these regulatory streamlining items are non-substantive 
amendments that correct minor errors or inconsistencies in the 
regulations.
    The regulatory streamlining items that we are finalizing for the 
in-use fuels regulations are changes that we believe are 
straightforward and should be made quickly.
    This action also includes a variety of technical amendments to 
certification-related requirements for engine and vehicle emission 
standards; adjusting the fuel economy label provisions to correspond to 
the new Tier 3 standards, removing obsolete regulatory text, and making 
several minor corrections and clarifications.
    Please refer to Section VI for a complete discussion of technical 
amendments and regulatory streamlining provisions and issues.

C. What will the impacts of the standards be?

    The final Tier 3 vehicle and fuel standards together will reduce 
dramatically emissions of NOX, VOC, PM2.5, and 
air toxics. The gasoline sulfur standards, which will take effect in 
2017, will provide large immediate reductions in emissions from 
existing gasoline vehicles and engines. NOX emissions are 
projected to be reduced by about 260,000 tons, or about 10 percent of 
emissions from on-highway vehicles, in 2018, and these emission 
reductions will increase over time as newer vehicles become a larger 
percentage of the fleet. In 2030, when 70 percent of the miles 
travelled are projected to be from vehicles that meet the fully phased-
in Tier 3 standards, we expect the NOX and VOC emissions to 
be reduced by about 330,000 tons and 170,000 tons, respectively, or 25 
percent and 16 percent of emissions from on-highway vehicles compared 
to their 2030 levels without the Tier 3 program. Emissions of CO are 
projected to decrease by almost 3.5 million tons, or 24 percent of 
emissions from on-highway vehicles. Emissions of many air toxics will 
also be reduced, including benzene, 1,3-butadiene, acetaldehyde, 
formaldehyde, acrolein and ethanol, with reductions projected to range 
from 10 to nearly 30 percent of national emissions from on-highway 
vehicles. We expect these reductions to continue beyond 2030 as more of 
the fleet continues to turn over to Tier 3 vehicles; for example, by 
2050, when nearly all of the fleet will have turned over to vehicles 
meeting the fully phased-in Tier 3 standards, we estimate the Tier 3 
program will reduce on-highway emissions of NOX and VOC 
nearly 31 percent from the level of emissions projected without Tier 3 
controls.\16\
---------------------------------------------------------------------------

    \16\ To estimate the benefits of the final Tier 3 rule, we 
performed air quality modeling for the year 2030.
---------------------------------------------------------------------------

    These reductions in emissions of NOX, VOC, 
PM2.5 and air toxics from the Tier 3 standards are projected 
to lead to significant decreases in ambient concentrations of ozone, 
PM2.5 and air toxics (including notable nationwide 
reductions in benzene concentrations) by 2030, and will immediately 
reduce ozone in 2017 when the sulfur controls take effect. Additional 
information on the emission and air quality impacts of the final Tier 3 
program is presented in Sections III.B and C.
    Exposure to ambient concentrations of ozone, PM2.5, and 
air toxics is linked to adverse human health impacts such as premature 
deaths as well as other important public health and environmental 
effects (see Section II.B). The final Tier 3 standards are expected to 
reduce these adverse impacts and yield significant benefits, including 
those we can monetize and those we are unable to quantify. We estimate 
that by 2030, the emission reductions of the Tier 3 standards will 
annually prevent between 660 and 1,500 PM-related premature deaths, 
between 110 and 500 ozone-related premature deaths, 81,000 work days 
lost, 210,000 school absence days, and approximately 1.1 million minor 
restricted-activity days. The estimated annual monetized health 
benefits of the Tier 3 standards in 2030 (2011$) is between $7.4 and 
$19 billion, assuming a 3-percent discount rate (or between $6.7 
billion and $18 billion assuming a 7-percent discount rate). We project 
the final fuel standards to cost on average 0.65 cent (i.e., less than 
a penny) per gallon of gasoline, and the final vehicle standards to 
have an

[[Page 23426]]

average cost that increases in proportion to the increase in stringency 
during the phase-in period, from $28 per vehicle in 2017 to $72 per 
vehicle in 2025, when the standards are fully phased in. We estimate 
the annual cost of the overall program in 2030 will be approximately 
$1.5 billion, and the 2030 benefits will be between 4.5 and 13 times 
the costs of the program.
    The estimated benefits in Table I-6 include all of the human health 
impacts we are able to quantify and monetize at this time. However, the 
full complement of human health and welfare effects associated with PM, 
ozone and air toxics remain unquantified because of current limitations 
in methods and/or available data. As a result, the health benefits 
quantified in this section are likely underestimates of the total 
benefits attributable to the final standards. See Sections VII and VIII 
for detailed descriptions of the costs and benefits of this action.

  Table I-6--Summary of Estimated Annual Benefits and Costs Associated
                      With the Final Tier 3 Program
                          [Billions, 2011$] \a\
------------------------------------------------------------------------
                         Description                              2030
------------------------------------------------------------------------
Vehicle Program Costs........................................      $0.76
Fuels Program Costs..........................................      $0.70
Total Estimated Costs \b\....................................       $1.5
Total Estimated Health Benefits: \c\ \d\ \e\ \f\
    3 percent discount rate..................................   $7.4-$19
    7 percent discount rate..................................   $6.7-$18
Annual Net Benefits (Total Benefits-Total Costs):
    3 percent discount rate..................................   $5.9-$18
    7 percent discount rate..................................   $5.2-$17
------------------------------------------------------------------------
Notes:
\a\ All estimates represent annual benefits and costs anticipated for
  the year 2030. Totals are rounded to two significant digits and may
  not sum due to rounding.
\b\ The calculation of annual costs does not require amortization of
  costs over time. Therefore, the estimates of annual cost do not
  include a discount rate or rate of return assumption (see Section VII
  of the preamble for more information on vehicle and fuel costs).
\c\ Total includes ozone and PM[ihel2].[ihel5] estimated benefits. Range
  was developed by adding the estimate from the Bell et al., 2004 ozone
  premature mortality function to PM[ihel2].[ihel5]-related premature
  mortality derived from the American Cancer Society cohort study
  (Krewski et al., 2009) for the low estimate and ozone premature
  mortality derived from the Levy et al., 2005 study to
  PM[ihel2].[ihel5]-related premature mortality derived from the Six-
  Cities (Lepeule et al., 2012) study for the high estimate.
\d\ Annual benefits analysis results reflect the use of a 3 percent and
  7 percent discount rate in the valuation of premature mortality and
  nonfatal myocardial infarctions, consistent with EPA and OMB
  guidelines for preparing economic analyses.
\e\ Valuation of premature mortality based on long-term PM exposure
  assumes discounting over the SAB recommended 20-year segmented lag
  structure described in the Regulatory Impact Analysis for the 2012 PM
  National Ambient Air Quality Standards (December, 2012).
\f\ Not all possible benefits are quantified and monetized in this
  analysis; the total monetized benefits presented here may therefore be
  underestimated. Potential benefit categories that have not been
  quantified and monetized, due to current limitations in methods and/or
  data availability, are listed in Table VIII-2. For example, we have
  not quantified a number of known or suspected health and welfare
  effects linked with reductions in ozone and PM (e.g., reductions in
  heart rate variability, reduced material damage to structures and
  cultural monuments, and reduced eutrophication in coastal areas). We
  are also unable to quantify health and welfare benefits associated
  with reductions in air toxics.

II. Why is EPA taking this action?

    The Clean Air Act authorizes EPA to establish emissions standards 
for motor vehicles to address air pollution that may reasonably be 
anticipated to endanger public health or welfare. EPA also has 
authority to establish fuel controls to address such air pollution. 
These statutory requirements are described in Section II.A.
    Emissions from motor vehicles and their fuels contribute to ambient 
levels of ozone, PM, NO2, sulfur dioxide (SO2) 
and CO, which are all pollutants for which EPA has established health-
based NAAQS. These pollutants are linked with respiratory and/or 
cardiovascular problems and other adverse health impacts leading to 
increased medication use, hospital admissions, emergency department 
visits, and premature mortality. Over 149 million people currently live 
in areas designated nonattainment for one or more of the current NAAQS 
for ozone, PM2.5, PM10, and SO2.\17\
---------------------------------------------------------------------------

    \17\ Data come from Summary Nonattainment Area Population 
Exposure Report, current as of December 5, 2013 at: http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket 
EPA-HQ-OAR-2011-0135.
---------------------------------------------------------------------------

    Motor vehicles also emit air toxics, and the most recent available 
data indicate that the majority of Americans continue to be exposed to 
ambient concentrations of air toxics at levels which have the potential 
to cause adverse health effects, including cancer, immune system 
damage, and neurological, reproductive, developmental, respiratory, and 
other health problems.\18\ A more detailed discussion of the health and 
environmental effects of these pollutants is included in Section II.B.
---------------------------------------------------------------------------

    \18\ U.S. EPA. (2011) Summary of Results for the 2005 National-
Scale Assessment. www.epa.gov/ttn/atw/nata2005/05pdf/sum_results.pdf.
---------------------------------------------------------------------------

    Cars and light trucks also continue to be a significant contributor 
to air pollution directly near roads, with gasoline vehicles accounting 
for more than 50 percent of near-road concentrations of some criteria 
and toxic pollutants.\19\ More than 50 million people live, work, or go 
to school in close proximity to high-traffic roadways, and the average 
American spends more than one hour traveling each day, with over 80 
percent of daily trips occurring by personal vehicle.\20\ \21\ \22\ 
\23\ \24\ Exposure to traffic-related pollutants has been linked with 
adverse health impacts such as respiratory problems (particularly in 
asthmatic children) and cardiovascular problems.
---------------------------------------------------------------------------

    \19\ For example, see Fujita, E.M; Campbell, D.E.; Zielinska, 
B.; Arnott, W.P.; Chow, J.C. (2011) Concentrations of Air Toxics in 
Motor Vehicle-Dominated Environments. Health Effects Institute 
Research Report 156. Available at http://www.healtheffects.org.
    \20\ Rowangould, G.M. (2013) A census of the US near-roadway 
population: public health and environmental justice considerations. 
Transportation Research Part D 25: 59-67.
    \21\ U.S. Census Bureau (2011). Current Housing Reports, Series 
H150/09, American Housing Survey for the United States: 2009. U.S. 
Government Printing Office, Washington, DC. Available at http://www.census.gov/hhes/www/housing/ahs/ahs09/ahs09.html.
    \22\ Drago, R.(2011). Secondary activities in the 2006 American 
Time Use Survey. U.S. Bureau of Labor Statistics Working Paper 446. 
Available at http://www.bls.gov.
    \23\ U.S. Department of Transportation, Bureau of Transportation 
Statistics. (2003) National Household Travel Survey 2001 Highlights 
Report. Government Printing Office, Washington, DC. Available at 
http://www.bts.gov/publications/highlights_of_the_2001_national_household_travel_survey/.
    \24\ Santos, A.; McGuckin, N, Yukiko Nakamoto, H.; Gray, D.; 
Liss, S. (2011) Summary of Travel Trends: 2009 National Household 
Travel Survey. Federal Highway Administration report no FHWA-PL-11-
022. Available at http://nhts.ornl.gov/publications.shtml.
---------------------------------------------------------------------------

    In the absence of additional controls such as Tier 3 standards, 
many areas will continue to have ambient ozone and PM2.5 
concentrations exceeding the NAAQS in the future. States and local 
areas are required to adopt control measures to attain the NAAQS and, 
once attained, to demonstrate that control measures are in place 
sufficient to maintain the NAAQS for ten years (and eight years later, 
a similar demonstration is required for another ten-year period). The 
Tier 3 standards will be a critical part of many areas' strategies to 
attain and maintain the NAAQS. Maintaining the NAAQS has been 
challenging for some areas in the past, particularly those where high 
population growth rates lead to significant annual increases in vehicle 
trips and vehicle miles traveled. Our air quality modeling for this 
final rule, which is described in more detail in Section III.C, 
projects that in 2018 a significant number of counties outside

[[Page 23427]]

CA will be within 10 percent of the 2008 ozone NAAQS, in the absence of 
additional controls. These counties in particular will benefit from the 
Tier 3 standards as they work to ensure long-term maintenance of the 
NAAQS.
    Section III provides more detail on how we expect this action will 
reduce motor vehicle emissions and ambient levels of pollution. We 
project that the Tier 3 program will meaningfully reduce ozone 
concentrations as early as 2017 (the first year of the program), and 
even more significantly in 2030. The estimated reductions are of 
significant enough magnitude to bring ozone levels in some counties 
from above the standard to below the standard, even without any 
additional controls. We also project that the Tier 3 standards will 
reduce ambient PM2.5 concentrations.
    Without this action to reduce nationwide motor vehicle emissions, 
areas would have to adopt other measures to reduce emissions from other 
sources under their state or local authority. Few other measures exist 
for providing multi-pollutant reductions of the same magnitude and 
cost-effectiveness as those expected from the Tier 3 standards. 
Furthermore, most states do not have the authority to lower the sulfur 
in gasoline, which is needed to immediately reduce emissions from the 
existing fleet and also enable new vehicles to meet the Tier 3 
emissions standards throughout their useful life.
    The projected reductions in ambient ozone and PM2.5 that 
will result from the Tier 3 standards will provide significant health 
benefits. We estimate that by 2030, the standards will annually prevent 
between 660 and 1,500 PM-related premature deaths, between 110 and 500 
ozone-related premature deaths, 81,000 work days lost, 210,000 school 
absence days, and approximately 1.1 million minor restricted-activity 
days (see Section VIII for more details). This action will also reduce 
air toxics; for example, we project that in 2030, the Tier 3 standards 
will decrease ambient benzene concentrations by 10-25 percent in some 
urban areas. Furthermore, the Tier 3 standards will reduce traffic-
associated pollution near major roads.
    EPA is finalizing Tier 3 vehicle and fuel standards as part of a 
comprehensive nationwide program for regulating all types of air 
pollution from motor vehicles. EPA recently finalized standards to 
reduce GHG emissions from light-duty vehicles, starting with model year 
2017.\25\ The Tier 3 standards in this final rule, which address non-
GHGs, will be implemented on the same timeframe, thus allowing 
manufacturers to optimize their vehicle redesigns over both sets of 
standards. Furthermore, the Tier 3 vehicle and fuel standards are also 
closely aligned with California's LEV III program, in such a way that 
manufacturers will be able to design a single vehicle for nationwide 
sales. This reduces the cost of compliance for auto manufacturers.
---------------------------------------------------------------------------

    \25\ 77 FR 62623 (October 15, 2012).
---------------------------------------------------------------------------

    This Tier 3 rulemaking responds to the President's request in his 
May 2010 memorandum for EPA to review the adequacy of its existing non-
GHG standards for new motor vehicles and fuels, and to promulgate new 
standards, if necessary, as part of a comprehensive approach to 
regulating motor vehicles.\26\ Based on our review, we have concluded 
that improved vehicle technology, combined with lower sulfur gasoline, 
make it feasible and cost-effective to reduce emissions well below the 
current Tier 2 levels. These emission reductions are necessary to 
reduce air pollution that is (and projected to continue to be) at 
levels that endanger public health and welfare.
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    \26\ The Presidential Memorandum is found at: http://www.whitehouse.gov/the-press-office/presidential-memorandum-regarding-fuel-efficiency-standards.
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A. Basis for Action Under the Clean Air Act

1. Clean Air Act Section 202
    We are setting motor vehicle emission standards under the authority 
of section 202 of the Clean Air Act. Section 202(a) provides EPA with 
general authority to prescribe vehicle standards, subject to any 
specific limitations elsewhere in the Act. EPA is setting standards for 
larger light-duty trucks and MDPVs under the general authority of 
section 202(a)(1) and under section 202(a)(3), which requires that 
standards applicable to emissions of hydrocarbons, NOX, CO 
and PM from heavy-duty vehicles \27\ reflect the greatest degree of 
emission reduction available for the model year to which such standards 
apply, giving appropriate consideration to cost, energy, and safety. In 
addition, section 202(k) provides EPA with authority to issue and 
revise regulations applicable to evaporative emissions of hydrocarbons 
from all gasoline-fueled motor vehicles during: (1) Operation, and (2) 
over 2 or more days of nonuse; under ozone-prone summertime conditions. 
Regulations under section 202(k) shall take effect as expeditiously as 
possible and shall require the greatest degree of emission reduction 
achievable by means reasonably expected to be available for production 
during any model year to which the regulations apply, giving 
appropriate consideration to fuel volatility, and to cost, energy, and 
safety factors associated with the application of the appropriate 
technology. Further, section 206 and in particular section 206(d) of 
the Clean Air Act authorizes EPA to establish methods and procedures 
for testing whether a motor vehicle or motor vehicle engine conforms 
with section 202 requirements.
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    \27\ LDTs that have gross vehicle weight ratings above 6000 lbs 
and all MDPVs are considered ``heavy-duty vehicles'' under the CAA. 
See section 202(b)(3)(C). For regulatory purposes, we generally 
refer to those LDTs which are above 6000 lbs GVWR and at or below 
8500 lbs GVWR as ``heavy light-duty trucks'' made up of LDT3s and 
LDT4s, and we have defined MDPVs primarily as vehicles between 8500 
and 10000 lbs GVWR designed primarily for the transportation of 
persons. See 40 CFR 86.1803-01.
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2. Clean Air Act Section 211
    We are adopting gasoline sulfur controls pursuant to our authority 
under section 211(c)(1) of the CAA. This section allows EPA to 
establish a fuel control if at least one of the following two criteria 
is met: (1) The emission products of the fuel cause or contribute to 
air pollution which may reasonably be anticipated to endanger public 
health or welfare; or (2) the emission products of the fuel will impair 
to a significant degree the performance of any emissions control device 
or system which is either in general use or which the Administrator 
finds has been developed to a point where in a reasonable time it will 
be in general use were the fuel control to be adopted. We are 
finalizing gasoline sulfur controls based on both of these criteria. 
Under the first criterion, we believe that gasoline with current levels 
of sulfur contributes to ambient levels of air pollution that endanger 
public health and welfare, as described in Section II.B. Under the 
second criterion, we believe that gasoline sulfur impairs the emissions 
control systems of vehicles, as discussed in Section III.A.2.

B. Overview of Public Health Impacts of Motor Vehicles and Fuels

    Motor vehicles emit pollutants that contribute to ambient 
concentrations of ozone, PM, NO2, SO2, CO, and 
air toxics. Motor vehicles are significant contributors to emissions of 
VOC and NOX, which contribute to the formation of both ozone 
and PM2.5. Over 149 million people currently live in 
counties designated nonattainment for one or more of the NAAQS, and 
this figure does not include the people living in areas with a risk of 
exceeding the

[[Page 23428]]

NAAQS in the future.\28\ The majority of Americans continue to be 
exposed to ambient concentrations of air toxics at levels which have 
the potential to cause adverse health effects.\29\ In addition, 
populations who live, work, or attend school near major roads 
experience elevated exposure concentrations to a wide range of air 
pollutants.\30\
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    \28\ Data come from Summary Nonattainment Area Population 
Exposure Report, current as of December 5, 2013 at: http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket 
EPA-HQ-OAR-2011-0135.
    \29\ U.S. EPA. (2011) Summary of Results for the 2005 National-
Scale Assessment. www.epa.gov/ttn/atw/nata2005/05pdf/sum_results.pdf.
    \30\ Health Effects Institute Panel on the Health Effects of 
Traffic-Related Air Pollution. (2010) Traffic-related air pollution: 
a critical review of the literature on emissions, exposure, and 
health effects. HEI Special Report 17. Available at http://www.healtheffects.org].
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    EPA has already adopted many emission control programs that are 
expected to reduce ambient pollution concentrations. As a result of 
these programs, the number of areas that continue to violate the ozone 
and PM2.5 NAAQS or have high levels of air toxics is 
expected to continue to decrease. However, the baseline air quality 
modeling completed for this rule predicts that without additional 
controls there will continue to be a need for reductions in ozone, 
PM2.5 and air toxics concentrations in some locations in the 
future. Section III.C of this preamble presents the air quality 
modeling results for this action.
1. Ozone
a. Background
    Ground-level ozone pollution is typically formed through reactions 
involving VOC and NOX in the lower atmosphere in the 
presence of sunlight. These pollutants, often referred to as ozone 
precursors, are emitted by many types of pollution sources, such as 
highway and nonroad motor vehicles and engines, power plants, chemical 
plants, refineries, makers of consumer and commercial products, 
industrial facilities, and smaller area sources.
    The science of ozone formation, transport, and accumulation is 
complex. Ground-level ozone is produced and destroyed in a cyclical set 
of chemical reactions, many of which are sensitive to temperature and 
sunlight. When ambient temperatures and sunlight levels remain high for 
several days and the air is relatively stagnant, ozone and its 
precursors can build up and result in more ozone than typically occurs 
on a single high-temperature day. Ozone and its precursors can be 
transported hundreds of miles downwind from precursor emissions, 
resulting in elevated ozone levels even in areas with low local VOC or 
NOX emissions.
b. Health Effects of Ozone
    This section provides a summary of the health effects associated 
with exposure to ambient concentrations of ozone.\31\ The information 
in this section is based on the information and conclusions in the 
February 2013 Integrated Science Assessment for Ozone (Ozone ISA) 
prepared by EPA's Office of Research and Development (ORD).\32\ The 
Ozone ISA concludes that human exposures to ambient concentrations of 
ozone are associated with a number of adverse health effects and 
characterizes the weight of evidence for these health effects.\33\ The 
discussion below highlights the Ozone ISA's conclusions pertaining to 
health effects associated with both short-term and long-term periods of 
exposure to ozone.
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    \31\ Human exposure to ozone varies over time due to changes in 
ambient ozone concentration and because people move between 
locations which have notable different ozone concentrations. Also, 
the amount of ozone delivered to the lung is not only influenced by 
the ambient concentrations but also by the individuals breathing 
route and rate.
    \32\ U.S. EPA. Integrated Science Assessment of Ozone and 
Related Photochemical Oxidants (Final Report). U.S. Environmental 
Protection Agency, Washington, DC, EPA/600/R-10/076F, 2013. The ISA 
is available at http://cfpub.epa.gov/ncea/isa/recordisplay.cfm?deid=247492#Download.
    \33\ The ISA evaluates evidence and draws conclusions on the 
causal relationship between relevant pollutant exposures and health 
effects, assigning one of five ``weight of evidence'' 
determinations: causal relationship, likely to be a causal 
relationship, suggestive of a causal relationship, inadequate to 
infer a causal relationship, and not likely to be a causal 
relationship. For more information on these levels of evidence, 
please refer to Table II in the Preamble of the ISA.
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    For short-term exposure to ozone, the Ozone ISA concludes that 
respiratory effects, including lung function decrements, pulmonary 
inflammation, exacerbation of asthma, respiratory-related hospital 
admissions, and mortality, are causally associated with ozone exposure. 
It also concludes that cardiovascular effects, including decreased 
cardiac function and increased vascular disease, and total mortality 
are likely to be causally associated with short-term exposure to ozone 
and that evidence is suggestive of a causal relationship between 
central nervous system effects and short-term exposure to ozone.
    For long-term exposure to ozone, the Ozone ISA concludes that 
respiratory effects, including new onset asthma, pulmonary inflammation 
and injury, are likely to be a causally related with ozone exposure. 
The Ozone ISA characterizes the evidence as suggestive of a causal 
relationship for associations between long-term ozone exposure and 
cardiovascular effects, reproductive and developmental effects, central 
nervous system effects and total mortality. The evidence is inadequate 
to infer a causal relationship between chronic ozone exposure and 
increased risk of lung cancer.
    Finally, interindividual variation in human responses to ozone 
exposure can result in some groups being at increased risk for 
detrimental effects in response to exposure. The Ozone ISA identified 
several groups that are at increased risk for ozone-related health 
effects. These groups are people with asthma, children and older 
adults, individuals with reduced intake of certain nutrients (i.e., 
Vitamins C and E), outdoor workers, and individuals having certain 
genetic variants related to oxidative metabolism or inflammation. Ozone 
exposure during childhood can have lasting effects through adulthood. 
Such effects include altered function of the respiratory and immune 
systems. Children absorb higher doses (normalized to lung surface area) 
of ambient ozone, compared to adults, due to their increased time spent 
outdoors, higher ventilation rates relative to body size, and a 
tendency to breathe a greater fraction of air through the mouth. 
Children also have a higher asthma prevalence compared to adults. 
Additional children's vulnerability and susceptibility factors are 
listed in Section XII.G.
c. Current and Projected Concentrations of Ozone
    Concentrations that exceed the level of the ozone NAAQS occur in 
many parts of the country, including major population centers such as 
Atlanta, Baltimore, Chicago, Dallas, Houston, New York, Philadelphia, 
and Washington, DC. In addition, our modeling without the Tier 3 
controls projects that in the future we will continue to have many 
counties that will have ambient ozone concentrations above the level of 
the NAAQS (see Section III.C.1). States will need to meet the standard 
in the 2015-2032 time frame for the 2008 ozone NAAQS. The emission 
reductions and significant ambient ozone improvements from this rule, 
which will take effect starting in 2017, will be helpful to states as 
they work to attain and maintain the ozone NAAQS.
    The primary and secondary NAAQS for ozone are 8-hour standards with 
a level of 0.075 ppm. The most recent revision to the ozone standards 
was in 2008; the previous 8-hour ozone standards, set in 1997, had a 
level of 0.08 ppm. In 2004, the U.S. EPA

[[Page 23429]]

designated nonattainment areas for the 1997 8-hour ozone NAAQS.\34\ 
\35\ As of December 5, 2013, there were 39 ozone nonattainment areas 
for the 1997 ozone NAAQS composed of 216 full or partial counties with 
a total population of over 112 million. Nonattainment designations for 
the 2008 ozone standard were finalized on April 30, 2012 and May 31, 
2012.\36\ As of December 5, 2013, there were 46 ozone nonattainment 
areas for the 2008 ozone NAAQS, composed of 227 full or partial 
counties, with a population of over 123 million. As of December 5, 
2013, over 135 million people are living in ozone nonattainment 
areas.\37\
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    \34\ 69 FR 23858 (April 30, 2004).
    \35\ A nonattainment area is defined in the Clean Air Act (CAA) 
as an area that is violating an ambient standard or is contributing 
to a nearby area that is violating the standard.
    \36\ 77 FR 30088 (May 21, 2012) and 77 FR 34221 (June 11, 2012).
    \37\ The 135 million total is calculated by summing, without 
double counting, the 1997 and 2008 ozone nonattainment populations 
contained in the Summary Nonattainment Area Population Exposure 
report (http://www.epa.gov/oar/oaqps/greenbk/popexp.html). If there 
is a population associated with both the 1997 and 2008 nonattainment 
areas, and they are not the same, then the larger of the two 
populations is included in the sum.
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    States with ozone nonattainment areas are required to take action 
to bring those areas into attainment. The attainment date assigned to 
an ozone nonattainment area is based on the area's classification. Most 
ozone nonattainment areas were required to attain the 1997 8-hour ozone 
NAAQS in the 2007 to 2013 time frame and then to maintain it 
thereafter.\38\ The attainment dates for areas designated nonattainment 
for the 2008 8-hour ozone NAAQS are in the 2015 to 2032 timeframe, 
depending on the severity of the problem in each area. In addition, EPA 
is currently working on a review of the ozone NAAQS. If EPA revises the 
ozone standards pursuant to that review, the attainment dates 
associated with areas designated nonattainment for that NAAQS would be 
5 or more years after the final rule is promulgated, depending on the 
severity of the problem in each area.
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    \38\ The Los Angeles South Coast Air Basin 8-hour ozone 
nonattainment area and the San Joaquin Valley Air Basin 8-hour ozone 
nonattainment area are designated as Extreme and will have to attain 
before June 15, 2024. The Sacramento, Coachella Valley, Western 
Mojave and Houston 8-hour ozone nonattainment areas are designated 
as Severe and will have to attain by June 15, 2019.
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    EPA has already adopted many emission control programs that are 
expected to reduce ambient ozone levels. As a result of these and other 
federal, state and local programs, 8-hour ozone levels are expected to 
improve in the future. However, even with the implementation of all 
current state and federal regulations, there are projected to be 
counties violating the ozone NAAQS well into the future. Thus 
additional federal control programs, such as Tier 3, can assist areas 
with attainment dates in 2018 and beyond in attaining the NAAQS as 
expeditiously as practicable and may relieve areas with already 
stringent local regulations from some of the burden associated with 
adopting additional local controls.
2. Particulate Matter
a. Background
    Particulate matter is a highly complex mixture of solid particles 
and liquid droplets distributed among numerous atmospheric gases which 
interact with solid and liquid phases. Particles range in size from 
those smaller than 1 nanometer (10-\9\ meter) to over 100 
micrometer ([mu]m, or 10-\6\ meter) in diameter (for 
reference, a typical strand of human hair is 70 [mu]m in diameter and a 
grain of salt is about 100 [mu]m). Atmospheric particles can be grouped 
into several classes according to their aerodynamic and physical sizes, 
including ultrafine particles (<0.1 [mu]m), accumulation mode or `fine' 
particles (<1 to 3 [mu]m), and coarse particles (>1 to 3 [mu]m).\39\ 
For regulatory purposes, fine particles are measured as 
PM2.5 and inhalable or thoracic coarse particles are 
measured as PM10-2.5, corresponding to their size (diameter) 
range in micrometers. The EPA currently has standards that measure 
PM2.5 and PM10.\40\
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    \39\ U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F. Figure 3-1.
    \40\ Regulatory definitions of PM size fractions, and 
information on reference and equivalent methods for measuring PM in 
ambient air, are provided in 40 CFR Parts 50, 53, and 58. With 
regard to national ambient air quality standards (NAAQS) which 
provide protection against health and welfare effects, the 24-hour 
PM10 standard provides protection against effects 
associated with short-term exposure to thoracic coarse particles 
(i.e., PM10-2.5).
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    Particles span many sizes and shapes and may consist of hundreds of 
different chemicals. Particles are emitted directly from sources and 
are also formed through atmospheric chemical reactions; the former are 
often referred to as ``primary'' particles, and the latter as 
``secondary'' particles. Particle concentration and composition varies 
by time of year and location, and in addition to differences in source 
emissions, is affected by several weather-related factors, such as 
temperature, clouds, humidity, and wind. A further layer of complexity 
comes from particles' ability to shift between solid/liquid and gaseous 
phases, which is influenced by concentration and meteorology, 
especially temperature.
    Fine particles are produced primarily by combustion processes and 
by transformations of gaseous emissions (e.g., sulfur oxides 
(SOX), oxides of nitrogen, and volatile organic compounds 
(VOC)) in the atmosphere. The chemical and physical properties of 
PM2.5 may vary greatly with time, region, meteorology, and 
source category. Thus, PM2.5 may include a complex mixture 
of different components including sulfates, nitrates, organic 
compounds, elemental carbon and metal compounds. These particles can 
remain in the atmosphere for days to weeks and travel hundreds to 
thousands of kilometers.
b. Health Effects of PM
    Scientific studies show ambient PM is associated with a broad range 
of health effects. These health effects are discussed in detail in the 
December 2009 Integrated Science Assessment for Particulate Matter (PM 
ISA).\41\ The PM ISA summarizes health effects evidence associated with 
both short- and long-term exposures to PM2.5, 
PM10-2.5, and ultrafine particles. The PM ISA concludes that 
human exposures to ambient PM2.5 concentrations are 
associated with a number of adverse health effects and characterizes 
the weight of evidence for these health outcomes.\42\ The discussion 
below highlights the PM ISA's conclusions pertaining to health effects 
associated with both short- and long-term PM exposures. Further 
discussion of health effects associated with PM2.5 can also 
be found in the rulemaking documents for the most recent review of the 
PM NAAQS completed in 2012.43 44
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    \41\ U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F.
    \42\ The causal framework draws upon the assessment and 
integration of evidence from across epidemiological, controlled 
human exposure, and toxicological studies, and the related 
uncertainties that ultimately influence our understanding of the 
evidence. This framework employs a five-level hierarchy that 
classifies the overall weight of evidence and causality using the 
following categorizations: causal relationship, likely to be causal 
relationship, suggestive of a causal relationship, inadequate to 
infer a causal relationship, and not likely to be a causal 
relationship (U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F, Table 1-3).
    \43\ 78 FR 3086 (January 15, 2013), pages 3103-3104.
    \44\ 77 FR 38890 (June 29, 2012), pages 38906-38911.
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    The EPA concludes that a causal relationship exists between both 
long-

[[Page 23430]]

and short-term exposures to PM2.5 and premature mortality 
and cardiovascular effects and a likely causal relationship exists 
between long- and short-term PM2.5 exposures and respiratory 
effects. Further, there is evidence suggestive of a causal relationship 
between long-term PM2.5 exposures and other health effects, 
including developmental and reproductive effects (e.g., low birth 
weight, infant mortality) and carcinogenic, mutagenic, and genotoxic 
effects (e.g., lung cancer mortality).\45\
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    \45\ These causal inferences are based not only on the more 
expansive epidemiological evidence available in this review but also 
reflect consideration of important progress that has been made to 
advance our understanding of a number of potential biologic modes of 
action or pathways for PM-related cardiovascular and respiratory 
effects (U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F, chapter 5).
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    As summarized in the Final PM NAAQS rule, and discussed extensively 
in the 2009 PM ISA, the scientific evidence available since the 
completion of the 2006 PM NAAQS review significantly strengthens the 
link between long- and short-term exposure to PM2.5 and 
premature mortality, while providing indications that the magnitude of 
the PM2.5- mortality association with long-term exposures 
may be larger than previously estimated.46 47 The strongest 
evidence comes from recent studies investigating long-term exposure to 
PM2.5 and cardiovascular-related mortality. The evidence 
supporting a causal relationship between long-term PM2.5 
exposure and mortality also includes consideration of new studies that 
demonstrated an improvement in community health following reductions in 
ambient fine particles.
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    \46\ 78 FR 3103-3104 (January 15, 2013).
    \47\ U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F, chapter 6 (Section 6.5) 
and chapter 7 (Section 7.6).
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    Several studies evaluated in the 2009 PM ISA have examined the 
association between cardiovascular effects and long-term 
PM2.5 exposures in multi-city studies conducted in the U.S. 
and Europe. While studies were not available in the 2006 PM NAAQS 
review with regard to long-term exposure and cardiovascular-related 
morbidity, studies published since then have provided new evidence 
linking long-term exposure to PM2.5 with an array of 
cardiovascular effects such as heart attacks, congestive heart failure, 
stroke, and mortality. This evidence is coherent with studies of short-
term exposure to PM2.5 that have observed associations with 
a continuum of effects ranging from subtle changes in indicators of 
cardiovascular health to serious clinical events, such as increased 
hospitalizations and emergency department visits due to cardiovascular 
disease and cardiovascular mortality.\48\
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    \48\ U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F, chapter 2 (section 2.3.1 
and 2.3.2) and chapter 6.
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    As detailed in the 2009 PM ISA, extended analyses of studies 
available in the 2006 PM NAAQS review as well as epidemiological 
studies conducted in the U.S. and abroad published since then provide 
stronger evidence of respiratory-related morbidity effects associated 
with long-term PM2.5 exposure. The strongest evidence for 
respiratory-related effects is from studies that evaluated decrements 
in lung function growth (in children), increased respiratory symptoms, 
and asthma development. The strongest evidence from short-term 
PM2.5 exposure studies has been observed for increased 
respiratory-related emergency department visits and hospital admissions 
for chronic obstructive pulmonary disease (COPD) and respiratory 
infections.\49\
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    \49\ U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F, chapter 2 (section 2.3.1 
and 2.3.2) and chapter 6.
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    The body of scientific evidence detailed in the 2009 PM ISA is 
still limited with respect to associations between long-term 
PM2.5 exposures and developmental and reproductive effects 
as well as cancer, mutagenic, and genotoxic effects, but is somewhat 
expanded from the 2006 review. The strongest evidence for an 
association between PM2.5 and developmental and reproductive 
effects comes from epidemiological studies of low birth weight and 
infant mortality, especially due to respiratory causes during the post-
neonatal period (i.e., 1 month to 12 months of age).\50\ With regard to 
cancer effects, ``[m]ultiple epidemiologic studies have shown a 
consistent positive association between PM2.5 and lung 
cancer mortality, but studies have generally not reported associations 
between PM2.5 and lung cancer incidence.'' \51\
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    \50\ U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F, chapter 2 (section 2.3.1 
and 2.3.2) and chapter 7.
    \51\ U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F. pg 2-13.
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    Specific groups within the general population are at increased risk 
for experiencing adverse health effects related to PM 
exposures.52 53 54 55 The evidence detailed in the 2009 PM 
ISA expands our understanding of previously identified at-risk 
populations and lifestages (i.e., children, older adults, and 
individuals with pre-existing heart and lung disease) and supports the 
identification of additional at-risk populations (e.g., persons with 
lower socioeconomic status, genetic differences). Additionally, there 
is emerging, though still limited, evidence for additional potentially 
at-risk populations and lifestages, such as those with diabetes, people 
who are obese, pregnant women, and the developing fetus.\56\
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    \52\ U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F. Chapter 8 and Chapter 2.
    \53\ 77 FR 38890 (June 29, 2012).
    \54\ 78 FR 3104 (January 15, 2013).
    \55\ U.S. EPA. (2011). Policy Assessment for the Review of the 
PM NAAQS. U.S. Environmental Protection Agency, Washington, DC, EPA/
452/R-11-003. section 2.2.1.
    \56\ U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F. Chapter 8 and Chapter 2 
(Section 2.4.1).
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    For PM10-2.5, the 2009 PM ISA concluded that available 
evidence was suggestive of a causal relationship between short-term 
exposures to PM10-2.5 and cardiovascular effects (e.g., 
hospital admissions and ED visits, changes in cardiovascular function), 
respiratory effects (e.g, ED visits and hospital admissions, increase 
in markers of pulmonary inflammation), and premature mortality. Data 
were inadequate to draw conclusions regarding the relationships between 
long-term exposure to PM10-2.5 and various health 
effects.57 58 59
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    \57\ U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F. Section 2.3.4 and Table 
2-6.
    \58\ 78 FR 3167-8 (January 15, 2013).
    \59\ 77 FR 38947-51 (June 29, 2012).
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    For ultrafine particles, the 2009 PM ISA concluded that the 
evidence was suggestive of a causal relationship between short-term 
exposures and cardiovascular effects, including changes in heart rhythm 
and vasomotor function (the ability of blood vessels to expand and 
contract). It also concluded that there was evidence suggestive of a 
causal relationship between short-term exposure to ultrafine particles 
and respiratory effects, including lung function and pulmonary 
inflammation,

[[Page 23431]]

with limited and inconsistent evidence for increases in ED visits and 
hospital admissions. Data were inadequate to draw conclusions regarding 
the relationship between short-term exposure to ultrafine particle and 
additional health effects including premature mortality as well as 
long-term exposure to ultrafine particles and all health outcomes 
evaluated.60 61
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    \60\ U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F. Section 2.3.5 and Table 
2-6.
    \61\ 78 FR 3121 (January 15, 2013).
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c. Current and Projected Concentrations of PM2.5
    There are two primary NAAQS for PM2.5: an annual 
standard (12.0 micrograms per cubic meter ([mu]g/m\3\)) and a 24-hour 
standard (35 [mu]g/m\3\), and two secondary NAAQS for PM2.5: 
an annual standard (15.0 [mu]g/m\3\) and a 24-hour standard (35 [mu]g/
m\3\). The initial PM2.5 standards were set in 1997 and 
revisions to the standards were finalized in 2006 and in December 2012. 
The December 2012 rule revised the level of the primary annual 
PM2.5 standard from 15.0 [mu]g/m\3\ to 12.0 [mu]g/m\3\.\62\
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    \62\ U.S. EPA (2012). National Ambient Air Quality Standards for 
Particulate Matter. http://www.epa.gov/PM/2012/finalrule.pdf. 78 FR 
3164.
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    There are many areas of the country that are currently in 
nonattainment for the annual and 24-hour PM2.5 NAAQS. Our 
modeling without the Tier 3 controls projects that in the future we 
will continue to have many areas that will have ambient 
PM2.5 concentrations above the level of the NAAQS (see 
Section III.C.2). States will need to meet the 2006 24-hour standards 
in the 2015-2019 timeframe and the 2012 primary annual standard in the 
2021-2025 timeframe. The emission reductions and improvements in 
ambient PM2.5 concentrations from this action, which will 
take effect starting in 2017, will be helpful to states as they work to 
attain and maintain the PM2.5 NAAQS.
    In 2005 the EPA designated 39 nonattainment areas for the 1997 
PM2.5 NAAQS.\63\ As of December 5, 2013, over 68 million 
people lived in the 24 areas that are still designated as nonattainment 
for the 1997 annual PM2.5 NAAQS. These PM2.5 
nonattainment areas are comprised of 135 full or partial counties. EPA 
anticipates making initial area designation decisions for the 2012 
primary annual PM2.5 NAAQS in December 2014, with those 
designations likely becoming effective in early 2015.\64\ On November 
13, 2009 and February 3, 2011, the EPA designated 32 nonattainment 
areas for the 2006 24-hour PM2.5 NAAQS.\65\ As of December 
5, 2013, 28 of these areas remain designated as nonattainment, and they 
are composed of 104 full or partial counties with a population of over 
65 million. In total, there are currently 39 PM2.5 
nonattainment areas with a population of over 84 million people.\66\
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    \63\ 70 FR 19844 (April 14, 2005).
    \64\ U.S. EPA (2012). Fact Sheet: Implementing the Standards. 
http://www.epa.gov/airquality/particlepollution/2012/decfsimp.pdf.
    \65\ 74 FR 58688 (November 13, 2009) and 76 FR 6056 (February 3, 
2011).
    \66\ Data come from Summary Nonattainment Area Population 
Exposure Report, current as of July 31, 2013 at: http://www.epa.gov/oar/oaqps/greenbk/popexp.html and contained in Docket EPA-HQ-OAR-
2011-0135.
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    States with PM2.5 nonattainment areas will be required 
to take action to bring those areas into attainment in the future. 
Designated nonattainment areas not currently attaining the 1997 annual 
PM2.5 NAAQS are required to attain the NAAQS by 2015 and 
will be required to maintain the 1997 annual PM2.5 NAAQS 
thereafter. The 2006 24-hour PM2.5 nonattainment areas are 
required to attain the 2006 24-hour PM2.5 NAAQS in the 2015 
to 2019 time frame and will be required to maintain the 2006 24-hour 
PM2.5 NAAQS thereafter. Areas to be designated nonattainment 
for the 2012 primary annual PM2.5 NAAQS will likely be 
required to attain the 2012 NAAQS in the 2021 to 2025 time frame. The 
Tier 3 standards finalized here begin taking effect in 2017.
    The EPA has already adopted many mobile source emission control 
programs that are expected to reduce ambient PM concentrations. As a 
result of these and other federal, state and local programs, the number 
of areas that fail to meet the PM2.5 NAAQS in the future is 
expected to decrease. However, even with the implementation of all 
current state and federal regulations, there are projected to be 
counties violating the PM2.5 NAAQS well into the future. 
Thus additional federal control programs, such as Tier 3, can assist 
areas with attainment dates in 2017 and beyond in attaining the NAAQS 
as expeditiously as practicable and may relieve areas with already 
stringent local regulations from some of the burden associated with 
adopting additional local controls.
d. Current Concentrations of PM10
    In the December 2012 action in which the EPA promulgated the 
revised primary annual PM2.5 NAAQS, the EPA also retained 
the existing primary and secondary 24-hour PM10 standards at 
150 [micro]g/m\3\. As of December 5, 2013, over 11 million people live 
in the 40 areas that are designated as nonattainment for the 
PM10 NAAQS. There are 33 full or partial counties that make 
up the PM10 nonattainment areas.
3. Oxides of Nitrogen and Sulfur
a. Background
    Nitrogen dioxide (NO2) is a member of the NOX 
family of gases. Most NO2 is formed in the air through the 
oxidation of nitric oxide (NO) emitted when fuel is burned at a high 
temperature. Sulfur dioxide (SO2), a member of the sulfur 
oxide (SOX) family of gases, is formed from burning fuels 
containing sulfur (e.g., coal or oil derived), extracting gasoline from 
oil, or extracting metals from ore.
    SO2 and NO2 and their gas phase oxidation 
products can dissolve in water droplets and further oxidize to form 
sulfuric and nitric acid which react with ammonia to form sulfates and 
nitrates, both of which are important components of ambient PM. The 
health effects of ambient PM are discussed in Section II.B.2.b of this 
preamble. NOX and VOC are the two major precursors of ozone. 
The health effects of ozone are covered in Section II.B.2.1.b.
b. Health Effects of NO2
    The most recent review of the health effects of oxides of nitrogen 
completed by the EPA can be found in the 2008 Integrated Science 
Assessment for Nitrogen Oxides (NOX ISA).\67\ The EPA 
concluded that the findings of epidemiologic, controlled human 
exposure, and animal toxicological studies provide evidence that is 
sufficient to infer a likely causal relationship between respiratory 
effects and short-term NO2 exposure. The 2008 NOX 
ISA concluded that the strongest evidence for such a relationship comes 
from epidemiologic studies of respiratory effects including increased 
respiratory symptoms, emergency department visits, and hospital 
admissions. Based on both short- and long-term exposure studies, the 
2008 NOX ISA concluded that individuals with preexisting 
pulmonary conditions (e.g., asthma or COPD), children, and older adults 
are potentially at greater risk of NO2-related respiratory 
effects. Based on findings from controlled human exposure studies, the 
2008 NOX ISA also drew two broad conclusions regarding 
airway responsiveness following NO2 exposure. First, the 
NOX

[[Page 23432]]

ISA concluded that NO2 exposure may enhance the sensitivity 
to allergen-induced decrements in lung function and increase the 
allergen-induced airway inflammatory response following 30-minute 
exposures of asthmatic adults to NO2 concentrations as low 
as 260 ppb. Second, exposure to NO2 has been found to 
enhance the inherent responsiveness of the airway to subsequent 
nonspecific challenges in controlled human exposure studies of healthy 
and asthmatic adults. Small but statistically significant increases in 
nonspecific airway hyperresponsiveness were reported for asthmatic 
adults following 30-minute exposures to 200-300 ppb NO2 and 
following 1-hour exposures of asthmatics to 100 ppb NO2. 
Enhanced airway responsiveness could have important clinical 
implications for asthmatics since transient increases in airway 
responsiveness following NO2 exposure have the potential to 
increase symptoms and worsen asthma control. Together, the 
epidemiologic and experimental data sets form a plausible, consistent, 
and coherent description of a relationship between NO2 
exposures and an array of adverse health effects that range from the 
onset of respiratory symptoms to hospital admission.
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    \67\ U.S. EPA (2008). Integrated Science Assessment for Oxides 
of Nitrogen--Health Criteria (Final Report). EPA/600/R-08/071. 
Washington, DC: U.S.EPA.
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    In evaluating a broader range of health effects, the 2008 
NOX ISA concluded evidence was ``suggestive but not 
sufficient to infer a causal relationship'' between short-term 
NO2 exposure and premature mortality and between long-term 
NO2 exposure and respiratory effects. The latter was based 
largely on associations observed between long-term NO2 
exposure and decreases in lung function growth in children. 
Furthermore, the 2008 NOX ISA concluded that evidence was 
``inadequate to infer the presence or absence of a causal 
relationship'' between short-term NO2 exposure and 
cardiovascular effects as well as between long-term NO2 
exposure and cardiovascular effects, reproductive and developmental 
effects, premature mortality, and cancer.\68\ The conclusions for these 
health effect categories were informed by uncertainties in the evidence 
base such as the independent effects of NO2 exposure within 
the broader mixture of traffic-related pollutants, limited evidence 
from experimental studies, and/or an overall limited literature base.
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    \68\ U.S. EPA (2008). Integrated Science Assessment for Oxides 
of Nitrogen--Health Criteria (Final Report). EPA/600/R-08/071. 
Washington, DC: U.S.EPA.
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c. Health Effects of SO2
    Information on the health effects of SO2 can be found in 
the 2008 Integrated Science Assessment for Sulfur Oxides 
(SO2 ISA).\69\ Short-term peaks of SO2 have long 
been known to cause adverse respiratory health effects, particularly 
among individuals with asthma. In addition to those with asthma (both 
children and adults), potentially sensitive groups include all children 
and the elderly. During periods of elevated ventilation, asthmatics may 
experience symptomatic bronchoconstriction within minutes of exposure. 
Following an extensive evaluation of health evidence from epidemiologic 
and laboratory studies, the EPA concluded that there is a causal 
relationship between respiratory health effects and short-term exposure 
to SO2. Separately, based on an evaluation of the 
epidemiologic evidence of associations between short-term exposure to 
SO2 and mortality, the EPA concluded that the overall 
evidence is suggestive of a causal relationship between short-term 
exposure to SO2 and mortality.
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    \69\ U.S. EPA. (2008). Integrated Science Assessment (ISA) for 
Sulfur Oxides--Health Criteria (Final Report). EPA/600/R-08/047F. 
Washington, DC: U.S. Environmental Protection Agency.
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d. Current Concentrations of NO2
    The EPA most recently completed a review of the primary NAAQS for 
NO2 in January 2010. There are two primary NAAQS for 
NO2: an annual standard (53 ppb) and a 1-hour standard (100 
ppb). The EPA promulgated area designations in the Federal Register on 
February 17, 2012. In this initial round of designations, all areas of 
the country were designated as ``unclassifiable/attainment'' for the 
2010 NO2 NAAQS based on data from the existing air quality 
monitoring network. The EPA and state agencies are working to establish 
an expanded network of NO2 monitors, expected to be deployed 
in the 2014-2017 time frame. Once three years of air quality data have 
been collected from the expanded network, the EPA will be able to 
evaluate NO2 air quality in additional 
locations.70 71
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    \70\ U.S. EPA. (2012). Fact Sheet--Air Quality Designations for 
the 2010 Primary Nitrogen Dioxide (NO2) National Ambient 
Air Quality Standards. http://www.epa.gov/airquality/nitrogenoxides/designations/pdfs/20120120FS.pdf.
    \71\ U.S. Environmental Protection Agency (2013). Revision to 
Ambient Nitrogen Dioxide Monitoring Requirements. March 7, 2013. 
http://www.epa.gov/airquality/nitrogenoxides/pdfs/20130307fr.pdf.
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e. Current Concentrations of SO2
    The EPA most recently completed a review of the primary 
SO2 NAAQS in June 2010. The current primary NAAQS for 
SO2 is a 1-hour standard of 75 ppb. The EPA finalized the 
initial area designations for 29 nonattainment areas in 16 states in a 
notice published in the Federal Register on August 5, 2013. In this 
first round of designations, EPA only designated nonattainment areas 
that were violating the standard based on existing air quality 
monitoring data provided by the states. The Agency did not have 
sufficient information to designate any area as ``attainment'' or make 
final decisions about areas for which additional modeling or monitoring 
is needed (78 FR 47191, August 5, 2013). EPA anticipates designating 
areas for the revised SO2 standard in multiple rounds.
4. Carbon Monoxide
    Carbon monoxide (CO) is a colorless, odorless gas emitted from 
combustion processes. Nationally and, particularly in urban areas, the 
majority of CO emissions to ambient air come from mobile sources.
a. Health Effects of Carbon Monoxide
    Information on the health effects of CO can be found in the January 
2010 Integrated Science Assessment for Carbon Monoxide (CO ISA).\72\ 
The CO ISA concludes that ambient concentrations of CO are associated 
with a number of adverse health effects.\73\ This section provides a 
summary of the health effects associated with exposure to ambient 
concentrations of CO.\74\
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    \72\ U.S. EPA, (2010). Integrated Science Assessment for Carbon 
Monoxide (Final Report). U.S. Environmental Protection Agency, 
Washington, DC, EPA/600/R-09/019F, 2010. Available at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=218686.
    \73\ The ISA evaluates the health evidence associated with 
different health effects, assigning one of five ``weight of 
evidence'' determinations: causal relationship, likely to be a 
causal relationship, suggestive of a causal relationship, inadequate 
to infer a causal relationship, and not likely to be a causal 
relationship. For definitions of these levels of evidence, please 
refer to Section 1.6 of the ISA.
    \74\ Personal exposure includes contributions from many sources, 
and in many different environments. Total personal exposure to CO 
includes both ambient and nonambient components; and both components 
may contribute to adverse health effects.
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    Controlled human exposure studies of subjects with coronary artery 
disease show a decrease in the time to onset of exercise-induced angina 
(chest pain) and electrocardiogram changes following CO exposure. In 
addition, epidemiologic studies show associations between short-term CO 
exposure and cardiovascular morbidity, particularly increased emergency 
room visits and hospital admissions for coronary heart

[[Page 23433]]

disease (including ischemic heart disease, myocardial infarction, and 
angina). Some epidemiologic evidence is also available for increased 
hospital admissions and emergency room visits for congestive heart 
failure and cardiovascular disease as a whole. The CO ISA concludes 
that a causal relationship is likely to exist between short-term 
exposures to CO and cardiovascular morbidity. It also concludes that 
available data are inadequate to conclude that a causal relationship 
exists between long-term exposures to CO and cardiovascular morbidity.
    Animal studies show various neurological effects with in-utero CO 
exposure. Controlled human exposure studies report central nervous 
system and behavioral effects following low-level CO exposures, 
although the findings have not been consistent across all studies. The 
CO ISA concludes the evidence is suggestive of a causal relationship 
with both short- and long-term exposure to CO and central nervous 
system effects.
    A number of studies cited in the CO ISA have evaluated the role of 
CO exposure in birth outcomes such as preterm birth or cardiac birth 
defects. The epidemiologic studies provide limited evidence of a CO-
induced effect on preterm births and birth defects, with weak evidence 
for a decrease in birth weight. Animal toxicological studies have found 
perinatal CO exposure to affect birth weight, as well as other 
developmental outcomes. The CO ISA concludes the evidence is suggestive 
of a causal relationship between long-term exposures to CO and 
developmental effects and birth outcomes.
    Epidemiologic studies provide evidence of associations between 
ambient CO concentrations and respiratory morbidity such as changes in 
pulmonary function, respiratory symptoms, and hospital admissions. A 
limited number of epidemiologic studies considered copollutants such as 
ozone, SO2, and PM in two-pollutant models and found that CO 
risk estimates were generally robust, although this limited evidence 
makes it difficult to disentangle effects attributed to CO itself from 
those of the larger complex air pollution mixture. Controlled human 
exposure studies have not extensively evaluated the effect of CO on 
respiratory morbidity. Animal studies at levels of 50-100 ppm CO show 
preliminary evidence of altered pulmonary vascular remodeling and 
oxidative injury. The CO ISA concludes that the evidence is suggestive 
of a causal relationship between short-term CO exposure and respiratory 
morbidity, and inadequate to conclude that a causal relationship exists 
between long-term exposure and respiratory morbidity.
    Finally, the CO ISA concludes that the epidemiologic evidence is 
suggestive of a causal relationship between short-term concentrations 
of CO and mortality. Epidemiologic studies provide evidence of an 
association between short-term exposure to CO and mortality, but 
limited evidence is available to evaluate cause-specific mortality 
outcomes associated with CO exposure. In addition, the attenuation of 
CO risk estimates which was often observed in copollutant models 
contributes to the uncertainty as to whether CO is acting alone or as 
an indicator for other combustion-related pollutants. The CO ISA also 
concludes that there is not likely to be a causal relationship between 
relevant long-term exposures to CO and mortality.
b. Current Concentrations of CO
    There are two NAAQS for CO: an 8-hour standard (9 ppm) and a 1-hour 
standard (35 ppm). The primary NAAQS for CO were retained in August 
2011. There are currently no CO nonattainment areas; as of September 
27, 2010, all CO nonattainment areas were redesignated to maintenance 
areas. The designations were based on the existing community-wide 
monitoring network. EPA is making changes to the ambient air monitoring 
requirements for CO. The new requirements are expected to result in 
approximately 52 CO monitors operating near roads within 52 urban areas 
by January 2015 (76 FR 54294, August 31, 2011).
5. Mobile Source Air Toxics
    Light-duty vehicle emissions contribute to ambient levels of air 
toxics known or suspected as human or animal carcinogens, or that have 
noncancer health effects. The population experiences an elevated risk 
of cancer and other noncancer health effects from exposure to the class 
of pollutants known collectively as ``air toxics.'' \75\ These 
compounds include, but are not limited to, benzene, 1,3-butadiene, 
formaldehyde, acetaldehyde, acrolein, polycyclic organic matter, and 
naphthalene. These compounds were identified as national or regional 
risk drivers or contributors in the 2005 National-scale Air Toxics 
Assessment and have significant inventory contributions from mobile 
sources.\76\
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    \75\ U.S. EPA. (2011) Summary of Results for the 2005 National-
Scale Assessment. www.epa.gov/ttn/atw/nata2005/05pdf/sum_results.pdf.
    \76\ U.S. EPA (2011) 2005 National-Scale Air Toxics Assessment. 
http://www.epa.gov/ttn/atw/nata2005.
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a. Health Effects of Air Toxics
i. Benzene
    The EPA's Integrated Risk Information System (IRIS) database lists 
benzene as a known human carcinogen (causing leukemia) by all routes of 
exposure, and concludes that exposure is associated with additional 
health effects, including genetic changes in both humans and animals 
and increased proliferation of bone marrow cells in 
mice.77 78 79 EPA states in its IRIS database that data 
indicate a causal relationship between benzene exposure and acute 
lymphocytic leukemia and suggest a relationship between benzene 
exposure and chronic non-lymphocytic leukemia and chronic lymphocytic 
leukemia. EPA's IRIS documentation for benzene also lists a range of 
2.2 x 10-6 to 7.8 x 10-6 as the unit risk 
estimate (URE) for benzene.80 81 The International Agency 
for Research on Carcinogens (IARC) has determined that benzene is a 
human carcinogen and the U.S. Department of Health and Human Services 
(DHHS) has characterized benzene as a known human 
carcinogen.82 83
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    \77\ U.S. EPA. (2000). Integrated Risk Information System File 
for Benzene. This material is available electronically at: http://www.epa.gov/iris/subst/0276.htm.
    \78\ International Agency for Research on Cancer, IARC 
monographs on the evaluation of carcinogenic risk of chemicals to 
humans, Volume 29, Some industrial chemicals and dyestuffs, 
International Agency for Research on Cancer, World Health 
Organization, Lyon, France 1982.
    \79\ Irons, R.D.; Stillman, W.S.; Colagiovanni, D.B.; Henry, 
V.A. (1992). Synergistic action of the benzene metabolite 
hydroquinone on myelopoietic stimulating activity of granulocyte/
macrophage colony-stimulating factor in vitro, Proc. Natl. Acad. 
Sci. 89:3691-3695.
    \80\ A unit risk estimate is defined as the increase in the 
lifetime risk of an individual who is exposed for a lifetime to 1 
[mu]g/m3 benzene in air.
    \81\ U.S. EPA. (2000). Integrated Risk Information System File 
for Benzene. This material is available electronically at: http://www.epa.gov/iris/subst/0276.htm.
    \82\ International Agency for Research on Cancer (IARC). (1987). 
Monographs on the evaluation of carcinogenic risk of chemicals to 
humans, Volume 29, Supplement 7, Some industrial chemicals and 
dyestuffs, World Health Organization, Lyon, France.
    \83\ U.S. Department of Health and Human Services National 
Toxicology Program. (2011). 12th Report on Carcinogens. Available 
at: http://ntp.niehs.nih.gov/?objectid=03C9AF75-E1BF-FF40-DBA9EC0928DF8B15.
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    A number of adverse noncancer health effects including blood 
disorders, such as preleukemia and aplastic anemia, have also been 
associated with

[[Page 23434]]

long-term exposure to benzene.84 85 The most sensitive 
noncancer effect observed in humans, based on current data, is the 
depression of the absolute lymphocyte count in blood.86 87 
EPA's inhalation reference concentration (RfC) for benzene is 30 [mu]g/
m\3\. The RfC is based on suppressed absolute lymphocyte counts seen in 
humans under occupational exposure conditions. In addition, recent 
work, including studies sponsored by the Health Effects Institute, 
provides evidence that biochemical responses are occurring at lower 
levels of benzene exposure than previously known.88 89 90 91 
EPA's IRIS program has not yet evaluated these new data. EPA does not 
currently have an acute reference concentration for benzene. The Agency 
for Toxic Substances and Disease Registry (ATSDR) Minimal Risk Level 
(MRL) for acute exposure to benzene is 29 [mu]g/m\3\ for 1-14 days 
exposure.92 93
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    \84\ Aksoy, M. (1989). Hematotoxicity and carcinogenicity of 
benzene. Environ. Health Perspect. 82: 193-197.
    \85\ Goldstein, B.D. (1988). Benzene toxicity. Occupational 
medicine. State of the Art Reviews. 3: 541-554.
    \86\ Rothman, N., G.L. Li, M. Dosemeci, W.E. Bechtold, G.E. 
Marti, Y.Z. Wang, M. Linet, L.Q. Xi, W. Lu, M.T. Smith, N. Titenko-
Holland, L.P. Zhang, W. Blot, S.N. Yin, and R.B. Hayes. (1996). 
Hematotoxicity among Chinese workers heavily exposed to benzene. Am. 
J. Ind. Med. 29: 236-246.
    \87\ U.S. EPA. (2002). Toxicological Review of Benzene 
(Noncancer Effects). Environmental Protection Agency, Integrated 
Risk Information System (IRIS), Research and Development, National 
Center for Environmental Assessment, Washington DC. This material is 
available electronically at http://www.epa.gov/iris/subst/0276.htm.
    \88\ Qu, O.; Shore, R.; Li, G.; Jin, X.; Chen, C.L.; Cohen, B.; 
Melikian, A.; Eastmond, D.; Rappaport, S.; Li, H.; Rupa, D.; 
Suramaya, R.; Songnian, W.; Huifant, Y.; Meng, M.; Winnik, M.; Kwok, 
E.; Li, Y.; Mu, R.; Xu, B.; Zhang, X.; Li, K. (2003). HEI Report 
115, Validation & Evaluation of Biomarkers in Workers Exposed to 
Benzene in China.
    \89\ Qu, Q., R. Shore, G. Li, X. Jin, L.C. Chen, B. Cohen, et 
al. (2002). Hematological changes among Chinese workers with a broad 
range of benzene exposures. Am. J. Industr. Med. 42: 275-285.
    \90\ Lan, Qing, Zhang, L., Li, G., Vermeulen, R., et al. (2004). 
Hematotoxically in Workers Exposed to Low Levels of Benzene. Science 
306: 1774-1776.
    \91\ Turtletaub, K.W. and Mani, C. (2003). Benzene metabolism in 
rodents at doses relevant to human exposure from Urban Air. Research 
Reports Health Effect Inst. Report No.113.
    \92\ U.S. Agency for Toxic Substances and Disease Registry 
(ATSDR). (2007). Toxicological profile for benzene. Atlanta, GA: 
U.S. Department of Health and Human Services, Public Health Service. 
http://www.atsdr.cdc.gov/ToxProfiles/tp3.pdf.
    \93\ A minimal risk level (MRL) is defined as an estimate of the 
daily human exposure to a hazardous substance that is likely to be 
without appreciable risk of adverse noncancer health effects over a 
specified duration of exposure.
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ii. Formaldehyde
    In 1991, EPA concluded that formaldehyde is a carcinogen based on 
nasal tumors in animal bioassays.\94\ An Inhalation Unit Risk for 
cancer and a Reference Dose for oral noncancer effects were developed 
by the Agency and posted on the IRIS database. Since that time, the 
National Toxicology Program (NTP) and International Agency for Research 
on Cancer (IARC) have concluded that formaldehyde is a known human 
carcinogen.95 96 97
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    \94\ EPA. Integrated Risk Information System. Formaldehyde 
(CASRN 50-00-0) http://www.epa.gov/iris/subst/0419/htm.
    \95\ National Toxicology Program, U.S. Department of Health and 
Human Services (HHS), 12th Report on Carcinogens, June 10, 2011.
    \96\ IARC Monographs on the Evaluation of Carcinogenic Risks to 
Humans Volume 88 (2006): Formaldehyde, 2-Butoxyethanol and 1-tert-
Butoxypropan-2-ol.
    \97\ IARC Mongraphs on the Evaluation of Carcinogenic Risks to 
Humans Volume 100F (2012): Formaldehyde.
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    The conclusions by IARC and NTP reflect the results of 
epidemiologic research published since 1991 in combination with 
previous animal, human and mechanistic evidence. Research conducted by 
the National Cancer Institute reported an increased risk of 
nasopharyngeal cancer and specific lymphohematopoietic malignancies 
among workers exposed to formaldehyde.98 99 100 A National 
Institute of Occupational Safety and Health study of garment workers 
also reported increased risk of death due to leukemia among workers 
exposed to formaldehyde.\101\ Extended follow-up of a cohort of British 
chemical workers did not report evidence of an increase in 
nasopharyngeal or lymphohematopoietic cancers, but a continuing 
statistically significant excess in lung cancers was reported.\102\ 
Finally, a study of embalmers reported formaldehyde exposures to be 
associated with an increased risk of myeloid leukemia but not brain 
cancer.\103\
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    \98\ Hauptmann, M..; Lubin, J. H.; Stewart, P. A.; Hayes, R. B.; 
Blair, A. 2003. Mortality from lymphohematopoetic malignancies among 
workers in formaldehyde industries. Journal of the National Cancer 
Institute 95: 1615-1623.
    \99\ Hauptmann, M..; Lubin, J. H.; Stewart, P. A.; Hayes, R. B.; 
Blair, A. 2004. Mortality from solid cancers among workers in 
formaldehyde industries. American Journal of Epidemiology 159: 1117-
1130.
    \100\ Beane Freeman, L. E.; Blair, A.; Lubin, J. H.; Stewart, P. 
A.; Hayes, R. B.; Hoover, R. N.; Hauptmann, M. 2009. Mortality from 
lymphohematopoietic malignancies among workers in formaldehyde 
industries: The National Cancer Institute cohort. J. National Cancer 
Inst. 101: 751-761.
    \101\ Pinkerton, L. E. 2004. Mortality among a cohort of garment 
workers exposed to formaldehyde: an update. Occup. Environ. Med. 61: 
193-200.
    \102\ Coggon, D, EC Harris, J Poole, KT Palmer. 2003. Extended 
follow-up of a cohort of British chemical workers exposed to 
formaldehyde. J National Cancer Inst. 95:1608-1615.
    \103\ Hauptmann, M,; Stewart P. A.; Lubin J. H.; Beane Freeman, 
L. E.; Hornung, R. W.; Herrick, R. F.; Hoover, R. N.; Fraumeni, J. 
F.; Hayes, R. B. 2009. Mortality from lymphohematopoietic 
malignancies and brain cancer among embalmers exposed to 
formaldehyde. Journal of the National Cancer Institute 101:1696-
1708.
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    Health effects of formaldehyde in addition to cancer were reviewed 
by the Agency for Toxics Substances and Disease Registry in 1999 \104\ 
and supplemented in 2010,\105\ and by the World Health 
Organization.\106\ These organizations reviewed the literature 
concerning effects on the eyes and respiratory system, the primary 
point of contact for inhaled formaldehyde, including sensory irritation 
of eyes and respiratory tract, pulmonary function, nasal 
histopathology, and immune system effects. In addition, research on 
reproductive and developmental effects and neurological effects were 
discussed.
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    \104\ ATSDR. 1999. Toxicological Profile for Formaldehyde, U.S. 
Department of Health and Human Services (HHS), July 1999.
    \105\ ATSDR. 2010. Addendum to theToxicological Profile for 
Formaldehyde. U.S. Department of Health and Human Services (HHS), 
October 2010.
    \106\ IPCS. 2002. Concise International Chemical Assessment 
Document 40. Formaldehyde. World Health Organization.
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    EPA released a draft Toxicological Review of Formaldehyde--
Inhalation Assessment through the IRIS program for peer review by the 
National Research Council (NRC) and public comment in June 2010.\107\ 
The draft assessment reviewed more recent research from animal and 
human studies on cancer and other health effects. The NRC released 
their review report in April 2011.\108\ The EPA is currently revising 
the draft assessment in response to this review.
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    \107\ EPA (U.S. Environmental Protection Agency). 2010. 
Toxicological Review of Formaldehyde (CAS No. 50-00-0)--Inhalation 
Assessment: In Support of Summary Information on the Integrated Risk 
Information System (IRIS). External Review Draft. EPA/635/R-10/002A. 
U.S. Environmental Protection Agency, Washington DC [online]. 
Available: http://cfpub.epa.gov/ncea/irs_drats/recordisplay.cfm?deid=223614.
    \108\ NRC (National Research Council). 2011. Review of the 
Environmental Protection Agency's Draft IRIS Assessment of 
Formaldehyde. Washington DC: National Academies Press. http://books.nap.edu/openbook.php?record_id=13142.
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iii. Acetaldehyde
    Acetaldehyde is classified in EPA's IRIS database as a probable 
human carcinogen, based on nasal tumors in rats, and is considered 
toxic by the inhalation, oral, and intravenous routes.\109\ The URE in 
IRIS for

[[Page 23435]]

acetaldehyde is 2.2 x 10-6 per [mu]g/m\3\.\110\ Acetaldehyde 
is reasonably anticipated to be a human carcinogen by the U.S. DHHS in 
the 12th Report on Carcinogens and is classified as possibly 
carcinogenic to humans (Group 2B) by the IARC.111 112 EPA is 
currently conducting a reassessment of cancer risk from inhalation 
exposure to acetaldehyde.
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    \109\ U.S. EPA (1991). Integrated Risk Information System File 
of Acetaldehyde. Research and Development, National Center for 
Environmental Assessment, Washington, DC. This material is available 
electronically at http://www.epa.gov/iris/subst/0290.htm.
    \110\ U.S. EPA (1991). Integrated Risk Information System File 
of Acetaldehyde. This material is available electronically at http://www.epa.gov/iris/subst/0290.htm.
    \111\ NTP. (2011). Report on Carcinogens, Twelfth Edition. 
Research Triangle Park, NC: U.S. Department of Health and Human 
Services, Public Health Service, National Toxicology Program. 499 
pp.
    \112\ International Agency for Research on Cancer (IARC). 
(1999). Re-evaluation of some organic chemicals, hydrazine, and 
hydrogen peroxide. IARC Monographs on the Evaluation of Carcinogenic 
Risk of Chemical to Humans, Vol 71. Lyon, France.
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    The primary noncancer effects of exposure to acetaldehyde vapors 
include irritation of the eyes, skin, and respiratory tract.\113\ In 
short-term (4 week) rat studies, degeneration of olfactory epithelium 
was observed at various concentration levels of acetaldehyde 
exposure.114 115 Data from these studies were used by EPA to 
develop an inhalation reference concentration of 9 [mu]g/m\3\. Some 
asthmatics have been shown to be a sensitive subpopulation to 
decrements in functional expiratory volume (FEV1 test) and 
bronchoconstriction upon acetaldehyde inhalation.\116\ The agency is 
currently conducting a reassessment of the health hazards from 
inhalation exposure to acetaldehyde.
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    \113\ U.S. EPA (1991). Integrated Risk Information System File 
of Acetaldehyde. This material is available electronically at http://www.epa.gov/iris/subst/0290.htm.
    \114\ U.S. EPA. (2003). Integrated Risk Information System File 
of Acrolein. Research and Development, National Center for 
Environmental Assessment, Washington, DC. This material is available 
electronically at http://www.epa.gov/iris/subst/0364.htm.
    \115\ Appleman, L.M., R.A. Woutersen, and V.J. Feron. (1982). 
Inhalation toxicity of acetaldehyde in rats. I. Acute and subacute 
studies. Toxicology. 23: 293-297.
    \116\ Myou, S.; Fujimura, M.; Nishi K.; Ohka, T.; and Matsuda, 
T. (1993) Aerosolized acetaldehyde induces histamine-mediated 
bronchoconstriction in asthmatics. Am. Rev. Respir.Dis.148(4 Pt 1): 
940-943.
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iv. Acrolein
    EPA most recently evaluated the toxicological and health effects 
literature related to acrolein in 2003 and concluded that the human 
carcinogenic potential of acrolein could not be determined because the 
available data were inadequate. No information was available on the 
carcinogenic effects of acrolein in humans and the animal data provided 
inadequate evidence of carcinogenicity.\117\ The IARC determined in 
1995 that acrolein was not classifiable as to its carcinogenicity in 
humans.\118\
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    \117\ U.S. EPA. (2003). Integrated Risk Information System File 
of Acrolein. Research and Development, National Center for 
Environmental Assessment, Washington, DC. This material is available 
at http://www.epa.gov/iris/subst/0364.htm.
    \118\ International Agency for Research on Cancer (IARC). 
(1995). Monographs on the evaluation of carcinogenic risk of 
chemicals to humans, Volume 63. Dry cleaning, some chlorinated 
solvents and other industrial chemicals, World Health Organization, 
Lyon, France.
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    Lesions to the lungs and upper respiratory tract of rats, rabbits, 
and hamsters have been observed after subchronic exposure to 
acrolein.\119\ The Agency has developed an RfC for acrolein of 0.02 
[mu]g/m\3\ and an RfD of 0.5 [mu]g/kg-day.\120\ EPA is considering 
updating the acrolein assessment with data that have become available 
since the 2003 assessment was completed.
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    \119\ U.S. EPA. (2003). Integrated Risk Information System File 
of Acrolein. Office of Research and Development, National Center for 
Environmental Assessment, Washington, DC. This material is available 
at http://www.epa.gov/iris/subst/0364.htm.
    \120\ U.S. EPA. (2003). Integrated Risk Information System File 
of Acrolein. Office of Research and Development, National Center for 
Environmental Assessment, Washington, DC. This material is available 
at http://www.epa.gov/iris/subst/0364.htm.
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    Acrolein is extremely acrid and irritating to humans when inhaled, 
with acute exposure resulting in upper respiratory tract irritation, 
mucus hypersecretion and congestion. The intense irritancy of this 
carbonyl has been demonstrated during controlled tests in human 
subjects, who suffer intolerable eye and nasal mucosal sensory 
reactions within minutes of exposure.\121\ These data and additional 
studies regarding acute effects of human exposure to acrolein are 
summarized in EPA's 2003 IRIS Human Health Assessment for 
acrolein.\122\ Studies in humans indicate that levels as low as 0.09 
ppm (0.21 mg/m\3\) for five minutes may elicit subjective complaints of 
eye irritation with increasing concentrations leading to more extensive 
eye, nose and respiratory symptoms. Acute exposures in animal studies 
report bronchial hyper-responsiveness. Based on animal data (more 
pronounced respiratory irritancy in mice with allergic airway disease 
in comparison to non-diseased mice \123\) and demonstration of similar 
effects in humans (e.g., reduction in respiratory rate), individuals 
with compromised respiratory function (e.g., emphysema, asthma) are 
expected to be at increased risk of developing adverse responses to 
strong respiratory irritants such as acrolein. EPA does not currently 
have an acute reference concentration for acrolein. The available 
health effect reference values for acrolein have been summarized by EPA 
and include an ATSDR MRL for acute exposure to acrolein of 7 [mu]g/m\3\ 
for 1-14 days exposure; and Reference Exposure Level (REL) values from 
the California Office of Environmental Health Hazard Assessment (OEHHA) 
for one-hour and 8-hour exposures of 2.5 [mu]g/m\3\ and 0.7 [mu]g/m\3\, 
respectively.\124\
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    \121\ U.S. EPA. (2003) Toxicological review of acrolein in 
support of summary information on Integrated Risk Information System 
(IRIS) National Center for Environmental Assessment, Washington, DC. 
EPA/635/R-03/003. p. 10. Available online at: http://www.epa.gov/ncea/iris/toxreviews/0364tr.pdf.
    \122\ U.S. EPA. (2003) Toxicological review of acrolein in 
support of summary information on Integrated Risk Information System 
(IRIS) National Center for Environmental Assessment, Washington, DC. 
EPA/635/R-03/003. Available online at: http://www.epa.gov/ncea/iris/toxreviews/0364tr.pdf.
    \123\ Morris JB, Symanowicz PT, Olsen JE, et al. (2003). 
Immediate sensory nerve-mediated respiratory responses to irritants 
in healthy and allergic airway-diseased mice. J Appl Physiol 
94(4):1563-1571.
    \124\ U.S. EPA. (2009). Graphical Arrays of Chemical-Specific 
Health Effect Reference Values for Inhalation Exposures (Final 
Report). U.S. Environmental Protection Agency, Washington, DC, EPA/
600/R-09/061, 2009. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=211003.
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v. 1,3-Butadiene
    EPA has characterized 1,3-butadiene as carcinogenic to humans by 
inhalation.125 126 The IARC has determined that 1,3-
butadiene is a human carcinogen and the U.S. DHHS has characterized 
1,3-butadiene as a known human carcinogen.127 128 129

[[Page 23436]]

There are numerous studies consistently demonstrating that 1,3-
butadiene is metabolized into genotoxic metabolites by experimental 
animals and humans. The specific mechanisms of 1,3-butadiene-induced 
carcinogenesis are unknown; however, the scientific evidence strongly 
suggests that the carcinogenic effects are mediated by genotoxic 
metabolites. Animal data suggest that females may be more sensitive 
than males for cancer effects associated with 1,3-butadiene exposure; 
there are insufficient data in humans from which to draw conclusions 
about sensitive subpopulations. The URE for 1,3-butadiene is 3 x 
10-5 per [mu]g/m\3\.\130\ 1,3-butadiene also causes a 
variety of reproductive and developmental effects in mice; no human 
data on these effects are available. The most sensitive effect was 
ovarian atrophy observed in a lifetime bioassay of female mice.\131\ 
Based on this critical effect and the benchmark concentration 
methodology, an RfC for chronic health effects was calculated at 0.9 
ppb (approximately 2 [mu]g/m\3\).
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    \125\ U.S. EPA. (2002). Health Assessment of 1,3-Butadiene. 
Office of Research and Development, National Center for 
Environmental Assessment, Washington Office, Washington, DC. Report 
No. EPA600-P-98-001F. This document is available electronically at 
http://www.epa.gov/iris/supdocs/buta-sup.pdf.
    \126\ U.S. EPA. (2002). ``Full IRIS Summary for 1,3-butadiene 
(CASRN 106-99-0)'' Environmental Protection Agency, Integrated Risk 
Information System (IRIS), Research and Development, National Center 
for Environmental Assessment, Washington, DC http://www.epa.gov/iris/subst/0139.htm.
    \127\ International Agency for Research on Cancer (IARC). 
(1999). Monographs on the evaluation of carcinogenic risk of 
chemicals to humans, Volume 71, Re-evaluation of some organic 
chemicals, hydrazine and hydrogen peroxide and Volume 97 (in 
preparation), World Health Organization, Lyon, France.
    \128\ International Agency for Research on Cancer (IARC). 
(2008). Monographs on the evaluation of carcinogenic risk of 
chemicals to humans, 1,3-Butadiene, Ethylene Oxide and Vinyl Halides 
(Vinyl Fluoride, Vinyl Chloride and Vinyl Bromide) Volume 97, World 
Health Organization, Lyon, France.
    \129\ NTP. (2011). Report on Carcinogens, Twelfth Edition. 
Research Triangle Park, NC: U.S. Department of Health and Human 
Services, Public Health Service, National Toxicology Program. 499 
pp.
    \130\ U.S. EPA. (2002). ``Full IRIS Summary for 1,3-butadiene 
(CASRN 106-99-0)'' Environmental Protection Agency, Integrated Risk 
Information System (IRIS), Research and Development, National Center 
for Environmental Assessment, Washington, DC. http://www.epa.gov/iris/subst/0139.htm.
    \131\ Bevan, C.; Stadler, J.C.; Elliot, G.S.; et al. (1996). 
Subchronic toxicity of 4-vinylcyclohexene in rats and mice by 
inhalation. Fundam. Appl. Toxicol. 32:1-10.
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vi. Ethanol
    EPA is planning to develop an assessment of the health effects of 
exposure to ethanol, a compound which is not currently listed on EPA's 
IRIS database. Extensive health effects data are available for 
ingestion of ethanol, while data on inhalation exposure effects are 
sparse. In developing the assessment, EPA is evaluating pharmacokinetic 
models as a means of extrapolating across species (animal to human) and 
across exposure routes (oral to inhalation) to better characterize the 
health hazards and dose-response relationships for low levels of 
ethanol exposure in the environment.
vii. Polycyclic Organic Matter
    The term polycyclic organic matter (POM) defines a broad class of 
compounds that includes the polycyclic aromatic hydrocarbon compounds 
(PAHs). One of these compounds, naphthalene, is discussed separately 
below. POM compounds are formed primarily from combustion and are 
present in the atmosphere in gas and particulate form. Cancer is the 
major concern from exposure to POM. Epidemiologic studies have reported 
an increase in lung cancer in humans exposed to diesel exhaust, coke 
oven emissions, roofing tar emissions, and cigarette smoke; all of 
these mixtures contain POM compounds.132 133 Animal studies 
have reported respiratory tract tumors from inhalation exposure to 
benzo[a]pyrene and alimentary tract and liver tumors from oral exposure 
to benzo[a]pyrene.\134\ In 1997 EPA classified seven PAHs 
(benzo[a]pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, 
benzo[k]fluoranthene, dibenz[a,h]anthracene, and indeno[1,2,3-
cd]pyrene) as Group B2, probable human carcinogens.\135\ Since that 
time, studies have found that maternal exposures to PAHs in a 
population of pregnant women were associated with several adverse birth 
outcomes, including low birth weight and reduced length at birth, as 
well as impaired cognitive development in preschool children (3 years 
of age).136 137 These and similar studies are being 
evaluated as a part of the ongoing IRIS assessment of health effects 
associated with exposure to benzo[a]pyrene.
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    \132\ Agency for Toxic Substances and Disease Registry (ATSDR). 
(1995). Toxicological profile for Polycyclic Aromatic Hydrocarbons 
(PAHs). Atlanta, GA: U.S. Department of Health and Human Services, 
Public Health Service. Available electronically at http://www.atsdr.cdc.gov/ToxProfiles/TP.asp?id=122&tid=25.
    \133\ U.S. EPA (2002). Health Assessment Document for Diesel 
Engine Exhaust. EPA/600/8-90/057F Office of Research and 
Development, Washington DC. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=29060.
    \134\ International Agency for Research on Cancer (IARC). 
(2012). Monographs on the Evaluation of the Carcinogenic Risk of 
Chemicals for Humans, Chemical Agents and Related Occupations. Vol. 
100F. Lyon, France.
    \135\ U.S. EPA (1997). Integrated Risk Information System File 
of indeno(1,2,3-cd)pyrene. Research and Development, National Center 
for Environmental Assessment, Washington, DC. This material is 
available electronically at http://www.epa.gov/ncea/iris/subst/0457.htm.
    \136\ Perera, F.P.; Rauh, V.; Tsai, W-Y.; et al. (2002). Effect 
of transplacental exposure to environmental pollutants on birth 
outcomes in a multiethnic population. Environ Health Perspect. 111: 
201-205.
    \137\ Perera, F.P.; Rauh, V.; Whyatt, R.M.; Tsai, W.Y.; Tang, 
D.; Diaz, D.; Hoepner, L.; Barr, D.; Tu, Y.H.; Camann, D.; Kinney, 
P. (2006). Effect of prenatal exposure to airborne polycyclic 
aromatic hydrocarbons on neurodevelopment in the first 3 years of 
life among inner-city children. Environ Health Perspect 114: 1287-
1292.
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viii. Naphthalene
    Naphthalene is found in small quantities in gasoline and diesel 
fuels. Naphthalene emissions have been measured in larger quantities in 
both gasoline and diesel exhaust compared with evaporative emissions 
from mobile sources, indicating it is primarily a product of 
combustion. Acute (short-term) exposure of humans to naphthalene by 
inhalation, ingestion, or dermal contact is associated with hemolytic 
anemia and damage to the liver and the nervous system.\138\ Chronic 
(long term) exposure of workers and rodents to naphthalene has been 
reported to cause cataracts and retinal damage.\139\ EPA released an 
external review draft of a reassessment of the inhalation 
carcinogenicity of naphthalene based on a number of recent animal 
carcinogenicity studies.\140\ The draft reassessment completed external 
peer review.\141\ Based on external peer review comments received, a 
revised draft assessment that considers all routes of exposure, as well 
as cancer and noncancer effects, is under development. The external 
review draft does not represent official agency opinion and was 
released solely for the purposes of external peer review and public 
comment. The National Toxicology Program listed naphthalene as 
``reasonably anticipated to be a human carcinogen'' in 2004 on the 
basis of bioassays reporting clear evidence of carcinogenicity in rats 
and some evidence of carcinogenicity in mice.\142\ California EPA has 
released a new risk assessment for naphthalene, and the IARC has 
reevaluated naphthalene and re-classified it as Group 2B: possibly 
carcinogenic to humans.\143\
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    \138\ U.S. EPA. 1998. Toxicological Review of Naphthalene 
(Reassessment of the Inhalation Cancer Risk), Environmental 
Protection Agency, Integrated Risk Information System, Research and 
Development, National Center for Environmental Assessment, 
Washington, DC. This material is available electronically at http://www.epa.gov/iris/subst/0436.htm.
    \139\ U.S. EPA. 1998. Toxicological Review of Naphthalene 
(Reassessment of the Inhalation Cancer Risk), Environmental 
Protection Agency, Integrated Risk Information System, Research and 
Development, National Center for Environmental Assessment, 
Washington, DC. This material is available electronically at http://www.epa.gov/iris/subst/0436.htm.
    \140\ U.S. EPA. (1998). Toxicological Review of Naphthalene 
(Reassessment of the Inhalation Cancer Risk), Environmental 
Protection Agency, Integrated Risk Information System, Research and 
Development, National Center for Environmental Assessment, 
Washington, DC. This material is available electronically at http://www.epa.gov/iris/subst/0436.htm.
    \141\ Oak Ridge Institute for Science and Education. (2004). 
External Peer Review for the IRIS Reassessment of the Inhalation 
Carcinogenicity of Naphthalene. August 2004. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=84403.
    \142\ NTP. (2011). Report on Carcinogens, Twelfth Edition. 
Research Triangle Park, NC: U.S. Department of Health and Human 
Services, Public Health Service, National Toxicology Program. 499 
pp.
    \143\ International Agency for Research on Cancer (IARC). 
(2002). Monographs on the Evaluation of the Carcinogenic Risk of 
Chemicals for Humans. Vol. 82. Lyon, France.
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    Naphthalene also causes a number of chronic non-cancer effects in 
animals,

[[Page 23437]]

including abnormal cell changes and growth in respiratory and nasal 
tissues.\144\ The current EPA IRIS assessment includes noncancer data 
on hyperplasia and metaplasia in nasal tissue that form the basis of 
the inhalation RfC of 3 [mu]g/m\3\.\145\ The ATSDR MRL for acute 
exposure to naphthalene is 0.6 mg/kg/day.
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    \144\ U.S. EPA. (1998). Toxicological Review of Naphthalene, 
Environmental Protection Agency, Integrated Risk Information System, 
Research and Development, National Center for Environmental 
Assessment, Washington, DC. This material is available 
electronically at http://www.epa.gov/iris/subst/0436.htm.
    \145\ U.S. EPA. (1998). Toxicological Review of Naphthalene. 
Environmental Protection Agency, Integrated Risk Information System 
(IRIS), Research and Development, National Center for Environmental 
Assessment, Washington, DC http://www.epa.gov/iris/subst/0436.htm.
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ix. Other Air Toxics
    In addition to the compounds described above, other compounds in 
gaseous hydrocarbon and PM emissions from motor vehicles will be 
affected by this action. Mobile source air toxic compounds that will 
potentially be impacted include ethylbenzene, propionaldehyde, toluene, 
and xylene. Information regarding the health effects of these compounds 
can be found in EPA's IRIS database.\146\
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    \146\ U.S. EPA Integrated Risk Information System (IRIS) 
database is available at: www.epa.gov/iris.
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b. Current Concentrations of Air Toxics
    The most recent available data indicate that the majority of 
Americans continue to be exposed to ambient concentrations of air 
toxics at levels which have the potential to cause adverse health 
effects.\147\ The levels of air toxics to which people are exposed vary 
depending on where people live and work and the kinds of activities in 
which they engage, as discussed in detail in U.S. EPA's most recent 
Mobile Source Air Toxics Rule.\148\ According to the National Air Toxic 
Assessment (NATA) for 2005,\149\ mobile sources were responsible for 43 
percent of outdoor toxic emissions and over 50 percent of the cancer 
risk and noncancer hazard associated with primary emissions. Mobile 
sources are also large contributors to precursor emissions which react 
to form secondary concentrations of air toxics. Formaldehyde is the 
largest contributor to cancer risk of all 80 pollutants quantitatively 
assessed in the 2005 NATA. Mobile sources were responsible for over 40 
percent of primary emissions of this pollutant in 2005, and are major 
contributors to formaldehyde precursor emissions. Benzene is also a 
large contributor to cancer risk, and mobile sources account for over 
70 percent of ambient exposure. Over the years, EPA has implemented a 
number of mobile source and fuel controls which have resulted in VOC 
reductions, which also reduced formaldehyde, benzene and other air 
toxic emissions.
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    \147\ U.S. EPA. (2011) Summary of Results for the 2005 National-
Scale Assessment. www.epa.gov/ttn/atw/nata2005/05pdf/sum_results.pdf.
    \148\ U.S. Environmental Protection Agency (2007). Control of 
Hazardous Air Pollutants from Mobile Sources; Final Rule. 72 FR 
8434, February 26, 2007.
    \149\ U.S. EPA. (2011). 2005 National-Scale Air Toxics 
Assessment. http://www.epa.gov/ttn/atw/nata2005/.
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6. Near-Roadway Pollution
    Locations in close proximity to major roadways generally have 
elevated concentrations of many air pollutants emitted from motor 
vehicles. Hundreds of such studies have been published in peer-reviewed 
journals, concluding that concentrations of CO, NO, NO2, 
benzene, aldehydes, particulate matter, black carbon, and many other 
compounds are elevated in ambient air within approximately 300-600 
meters (about 1,000-2,000 feet) of major roadways. Highest 
concentrations of most pollutants emitted directly by motor vehicles 
are found at locations within 50 meters (about 165 feet) of the edge of 
a roadway's traffic lanes.
    A recent large-scale review of air quality measurements in vicinity 
of major roadways between 1978 and 2008 concluded that the pollutants 
with the steepest concentration gradients in vicinities of roadways 
were CO, ultrafine particles, metals, elemental carbon (EC), NO, 
NOX, and several VOCs.\150\ These pollutants showed a large 
reduction in concentrations within 100 meters downwind of the roadway. 
Pollutants that showed more gradual reductions with distance from 
roadways included benzene, NO2, PM2.5, and 
PM10. In the review article, results varied based on the 
method of statistical analysis used to determine the trend.
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    \150\ Karner, A.A.; Eisinger, D.S.; Niemeier, D.A. (2010). Near-
roadway air quality: synthesizing the findings from real-world data. 
Environ Sci Technol 44: 5334-5344.
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    For pollutants with relatively high background concentrations 
relative to near-road concentrations, detecting concentration gradients 
can be difficult. For example, many aldehydes have high background 
concentrations as a result of photochemical breakdown of precursors 
from many different organic compounds. This can make detection of 
gradients around roadways and other primary emission sources difficult. 
However, several studies have measured aldehydes in multiple weather 
conditions, and found higher concentrations of many carbonyls downwind 
of roadways.\151, 152\ These findings suggest a substantial roadway 
source of these carbonyls.
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    \151\ Liu, W.; Zhang, J.; Kwon, J.l; et al. (2006). 
Concentrations and source characteristics of airborne carbonyl 
compounds measured outside urban residences. J Air Waste Manage 
Assoc 56: 1196-1204.
    \152\ Cahill, T.M.; Charles, M.J.; Seaman, V.Y. (2010). 
Development and application of a sensitive method to determine 
concentrations of acrolein and other carbonyls in ambient air. 
Health Effects Institute Research Report 149. Available at http://dx.doi.org.
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    In the past 15 years, many studies have been published with results 
reporting that populations who live, work, or go to school near high-
traffic roadways experience higher rates of numerous adverse health 
effects, compared to populations far away from major roads.\153\ In 
addition, numerous studies have found adverse health effects associated 
with spending time in traffic, such as commuting or walking along high-
traffic roadways.\154\ \155\ \156\ \157\ The health outcomes with the 
strongest evidence linking them with traffic-associated air pollutants 
are respiratory effects, particularly in asthmatic children, and 
cardiovascular effects.
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    \153\ In the widely-used PubMed database of health publications, 
between January 1, 1990 and August 18, 2011, 605 publications 
contained the keywords ``traffic, pollution, epidemiology,'' with 
approximately half the studies published after 2007.
    \154\ Laden, F.; Hart, J.E.; Smith, T.J.; Davis, M.E.; Garshick, 
E. (2007) Cause-specific mortality in the unionized U.S. trucking 
industry. Environmental Health Perspect 115:1192-1196.
    \155\ Peters, A.; von Klot, S.; Heier, M.; Trentinaglia, I.; 
H[ouml]rmann, A.; Wichmann, H.E.; L[ouml]wel, H. (2004) Exposure to 
traffic and the onset of myocardial infarction. New England J Med 
351: 1721-1730.
    \156\ Zanobetti, A.; Stone, P.H.; Spelzer, F.E.; Schwartz, J.D.; 
Coull, B.A.; Suh, H.H.; Nearling, B.D.; Mittleman, M.A.; Verrier, 
R.L.; Gold, D.R. (2009) T-wave alternans, air pollution and traffic 
in high-risk subjects. Am J Cardiol 104: 665-670.
    \157\ Dubowsky Adar, S.; Adamkiewicz, G.; Gold, D.R.; Schwartz, 
J.; Coull, B.A.; Suh, H. (2007) Ambient and microenvironmental 
particles and exhaled nitric oxide before and after a group bus 
trip. Environ Health Perspect 115: 507-512.
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    Numerous reviews of this body of health literature have been 
published as well. In 2010, an expert panel of the Health Effects 
Institute (HEI) published a review of hundreds of exposure, 
epidemiology, and toxicology studies.\158\ The panel rated how the 
evidence for each type of health outcome supported a conclusion of a 
causal association with traffic-associated air pollution as either 
``sufficient,'' ``suggestive but not sufficient,'' or ``inadequate and

[[Page 23438]]

insufficient.'' The panel categorized evidence of a causal association 
for exacerbation of childhood asthma as ``sufficient.'' The panel 
categorized evidence of a causal association for new onset asthma as 
between ``sufficient'' and as ``suggestive but not sufficient.'' 
``Suggestive of a causal association'' was how the panel categorized 
evidence linking traffic-associated air pollutants with exacerbation of 
adult respiratory symptoms and lung function decrement. It categorized 
as ``inadequate and insufficient'' evidence of a causal relationship 
between traffic-related air pollution and health care utilization for 
respiratory problems, new onset adult asthma, chronic obstructive 
pulmonary disease (COPD), nonasthmatic respiratory allergy, and cancer 
in adults and children. Other literature reviews have been published 
with conclusions similar to the HEI panel's.\159\ \160\ \161\ Health 
outcomes with few publications suggest the possibility of other effects 
still lacking sufficient evidence to draw definitive conclusions. Among 
these outcomes with a small number of positive studies are neurological 
impacts (e.g., autism and reduced cognitive function) and reproductive 
outcomes (e.g., preterm birth, low birth weight).\162\ \163\ \164\ 
\165\
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    \158\ Health Effects Institute Panel on the Health Effects of 
Traffic-Related Air Pollution. (2010). Traffic-related air 
pollution: a critical review of the literature on emissions, 
exposure, and health effects. HEI Special Report 17. Available at 
http://www.healtheffects.org.
    \159\ Boothe, V.L.; Shendell, D.G. (2008). Potential health 
effects associated with residential proximity to freeways and primay 
roads: review of scientific literature, 1999-2006. J Environ Health 
70: 33-41.
    \160\ Salam, M.T.; Islam, T.; Gilliland, F.D. (2008). Recent 
evidence for adverse effects of residential proximity to traffic 
sources on asthma. Curr Opin Pulm Med 14: 3-8.
    \161\ Raaschou-Nielsen, O.; Reynolds, P. (2006). Air pollution 
and childhood cancer: a review of the epidemiological literature. 
Int J Cancer 118: 2920-9.
    \162\ Volk, H.E.; Hertz-Picciotto, I.; Delwiche, L.; et al. 
(2011). Residential proximity to freeways and autism in the CHARGE 
study. Environ Health Perspect 119: 873-877.
    \163\ Franco-Suglia, S.; Gryparis, A.; Wright, R.O.; et al. 
(2007). Association of black carbon with cognition among children in 
a prospective birth cohort study. Am J Epidemiol. doi: 10.1093/aje/
kwm308. [Online at http://dx.doi.org]
    \164\ Power, M.C.; Weisskopf, M.G.; Alexeef, SE.; et al. (2011). 
Traffic-related air pollution and cognitive function in a cohort of 
older men. Environ Health Perspect 2011: 682-687.
    \165\ Wu, J.; Wilhelm, M.; Chung, J.; et al. (2011). Comparing 
exposure assessment methods for traffic-related air pollution in an 
adverse pregnancy outcome study. Environ Res 111: 685-6692.
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    In addition to health outcomes, particularly cardiopulmonary 
effects, conclusions of numerous studies suggest mechanisms by which 
traffic-related air pollution affects health. Numerous studies indicate 
that near-roadway exposures may increase systemic inflammation, 
affecting organ systems, including blood vessels and lungs.\166\ \167\ 
\168\ \169\ Long-term exposures in near-road environments have been 
associated with inflammation-associated conditions, such as 
atherosclerosis and asthma.\170\ \171\ \172\
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    \166\ Riediker, M. (2007). Cardiovascular effects of fine 
particulate matter components in highway patrol officers. Inhal 
Toxicol 19: 99-105. doi: 10.1080/08958370701495238 Available at 
http://dx.doi.org.
    \167\ Alexeef, SE.; Coull, B.A.; Gryparis, A.; et al. (2011). 
Medium-term exposure to traffic-related air pollution and markers of 
inflammation and endothelial function. Environ Health Perspect 119: 
481-486. doi:10.1289/ehp.1002560 Available at http://dx.doi.org.
    \168\ Eckel. S.P.; Berhane, K.; Salam, M.T.; et al. (2011). 
Traffic-related pollution exposure and exhaled nitric oxide in the 
Children's Health Study. Environ Health Perspect (IN PRESS). 
doi:10.1289/ehp.1103516. Available at http://dx.doi.org.
    \169\ Zhang, J.; McCreanor, J.E.; Cullinan, P.; et al. (2009). 
Health effects of real-world exposure diesel exhaust in persons with 
asthma. Res Rep Health Effects Inst 138. [Online at http://www.healtheffects.org.]
    \170\ Adar, S.D.; Klein, R.; Klein, E.K.; et al. (2010). Air 
pollution and the microvasculatory: a cross-sectional assessment of 
in vivo retinal images in the population-based Multi-Ethnic Study of 
Atherosclerosis. PLoS Med 7(11): E1000372. doi:10.1371/
journal.pmed.1000372. Available at http://dx.doi.org.
    \171\ Kan, H.; Heiss, G.; Rose, K.M.; et al. (2008). Proxpective 
analysis of traffic exposure as a risk factor for incident coronary 
heart disease: the Atherosclerosis Risk in Communities (ARIC) study. 
Environ Health Perspect 116: 1463-1468. doi:10.1289/ehp.11290. 
Available at http://dx.doi.org.
    \172\ McConnell, R.; Islam, T.; Shankardass, K.; et al. (2010). 
Childhood incident asthma and traffic-related air pollution at home 
and school. Environ Health Perspect 1021-1026.
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    Several studies suggest that some factors may increase 
susceptibility to the effects of traffic-associated air pollution. 
Several studies have found stronger respiratory associations in 
children experiencing chronic social stress, such as in violent 
neighborhoods or in homes with high family stress.\173\ \174\ \175\
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    \173\ Islam, T.; Urban, R.; Gauderman, W.J.; et al. (2011). 
Parental stress increases the detrimental effect of traffic exposure 
on children's lung function. Am J Respir Crit Care Med (In press).
    \174\ Clougherty, J.E.; Levy, J.I.; Kubzansky, L.D.; et al. 
(2007). Synergistic effects of traffic-related air pollution and 
exposure to violence on urban asthma etiology. Environ Health 
Perspect 115: 1140-1146.
    \175\ Chen, E.; Schrier, H.M.; Strunk, R.C.; et al. (2008). 
Chronic traffic-related air pollution and stress interact to predict 
biologic and clinical outcomes in asthma. Environ Health Perspect 
116: 970-5.
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    The risks associated with residence, workplace, or schools near 
major roads are of potentially high public health significance due to 
the large population in such locations. According to the 2009 American 
Housing Survey, over 22 million homes (17.0 percent of all U.S. housing 
units) were located within 300 feet of an airport, railroad, or highway 
with four or more lanes. This corresponds to a population of more than 
50 million U.S. residents in close proximity to high-traffic roadways 
or other transportation sources. Based on 2010 Census data, a 2013 
publication estimated that 19 percent of the U.S. population (over 59 
million people) lived within 500 meters of roads with at least 25,000 
annual average daily traffic (AADT), while about 3.2 percent of the 
population lived within 100 meters (about 300 feet) of such roads.\176\ 
Another 2013 study estimated that 3.7 percent of the U.S. population 
(about 11.3 million people) lived within 150 meters (about 500 feet) of 
interstate highways, or other freeways and expressways.\177\ As 
discussed in Section III, on average, populations near major roads have 
higher fractions of minority residents and lower socioeconomic status. 
Furthermore, on average, Americans spend more than an hour traveling 
each day, bringing nearly all residents into a high-exposure 
microenvironment for part of the day.
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    \176\ Rowangould, G.M. (2013) A census of the U.S. near-roadway 
population: public health and environmental justice considerations. 
Transportation Research Part D 25: 59-67.
    \177\ Boehmer, T.K.; Foster, S.L.; Henry, J.R.; Woghiren-
Akinnifesi, E.L.; Yip, F.Y. (2013) Residential proximity to major 
highways--United States, 2010. Morbidity and Mortality Weekly Report 
62(3);46-50.
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    In light of these concerns, EPA has required and is working with 
states to ensure that air quality monitors be placed near high-traffic 
roadways for determining NAAQS compliance for CO, NO2, and 
PM2.5 (in addition to those existing monitors located in 
neighborhoods and other locations farther away from pollution sources). 
Near-roadway monitors for NO2 begin operation between 2014 
and 2017 in Core Based Statistical Areas (CBSAs) with population of at 
least 500,000. Monitors for CO and PM2.5 begin operation 
between 2015 and 2017. These monitors will further our understanding of 
exposure in these locations.
    EPA continues to research near-road air quality, including the 
types of pollutants found in high concentrations near major roads and 
health problems associated with the mixture of pollutants near roads.
7. Environmental Impacts of Motor Vehicles and Fuels
a. Plant and Ecosystem Effects of Ozone
    The welfare effects of ozone can be observed across a variety of 
scales, i.e. subcellular, cellular, leaf, whole plant, population and 
ecosystem. Ozone effects that begin at small spatial scales, such as 
the leaf of an individual plant, when they occur at sufficient

[[Page 23439]]

magnitudes (or to a sufficient degree) can result in effects being 
propagated along a continuum to larger and larger spatial scales. For 
example, effects at the individual plant level, such as altered rates 
of leaf gas exchange, growth and reproduction can, when widespread, 
result in broad changes in ecosystems, such as productivity, carbon 
storage, water cycling, nutrient cycling, and community composition.
    Ozone can produce both acute and chronic injury in sensitive 
species depending on the concentration level and the duration of the 
exposure.\178\ In those sensitive species, \179\ effects from repeated 
exposure to ozone throughout the growing season of the plant tend to 
accumulate, so that even low concentrations experienced for a longer 
duration have the potential to create chronic stress on 
vegetation.\180\ Ozone damage to sensitive species includes impaired 
photosynthesis and visible injury to leaves. The impairment of 
photosynthesis, the process by which the plant makes carbohydrates (its 
source of energy and food), can lead to reduced crop yields, timber 
production, and plant productivity and growth. Impaired photosynthesis 
can also lead to a reduction in root growth and carbohydrate storage 
below ground, resulting in other, more subtle plant and ecosystems 
impacts.\181\ These latter impacts include increased susceptibility of 
plants to insect attack, disease, harsh weather, interspecies 
competition and overall decreased plant vigor. The adverse effects of 
ozone on areas with sensitive species could potentially lead to species 
shifts and loss from the affected ecosystems,\182\ resulting in a loss 
or reduction in associated ecosystem goods and services. Additionally, 
visible ozone injury to leaves can result in a loss of aesthetic value 
in areas of special scenic significance like national parks and 
wilderness areas and reduced use of sensitive ornamentals in 
landscaping.\183\
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    \178\ 73 FR 16486 (March 27, 2008).
    \179\ 73 FR 16491 (March 27, 2008). Only a small percentage of 
all the plant species growing within the U.S. (over 43,000 species 
have been catalogued in the USDA PLANTS database) have been studied 
with respect to ozone sensitivity.
    \180\ The concentration at which ozone levels overwhelm a 
plant's ability to detoxify or compensate for oxidant exposure 
varies. Thus, whether a plant is classified as sensitive or tolerant 
depends in part on the exposure levels being considered. Chapter 9, 
section 9.3.4 of U.S. EPA, 2013 Integrated Science Assessment for 
Ozone and Related Photochemical Oxidants. Office of Research and 
Development/National Center for Environmental Assessment. U.S. 
Environmental Protection Agency. EPA 600/R-10/076F.
    \181\ 73 FR 16492 (March 27, 2008).
    \182\ 73 FR 16493/16494 (March 27, 2008), Per footnote 2 above, 
ozone impacts could be occurring in areas where plant species 
sensitive to ozone have not yet been studied or identified.
    \183\ 73 FR 16490/16497 (March 27, 2008).
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    The Integrated Science Assessment (ISA) for Ozone presents more 
detailed information on how ozone affects vegetation and 
ecosystems.\184\ The ISA concludes that ambient concentrations of ozone 
are associated with a number of adverse welfare effects and 
characterizes the weight of evidence for different effects associated 
with ozone.\185\ The ISA concludes that visible foliar injury effects 
on vegetation, reduced vegetation growth, reduced productivity in 
terrestrial ecosystems, reduced yield and quality of agricultural 
crops, and alteration of below-ground biogeochemical cycles are 
causally associated with exposure to ozone. It also concludes that 
reduced carbon sequestration in terrestrial ecosystems, alteration of 
terrestrial ecosystem water cycling, and alteration of terrestrial 
community composition are likely to be causally associated with 
exposure to ozone.
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    \184\ U.S. EPA. Integrated Science Assessment of Ozone and 
Related Photochemical Oxidants (Final Report). U.S. Environmental 
Protection Agency, Washington, DC, EPA/600/R-10/076F, 2013. The ISA 
is available at http://cfpub.epa.gov/ncea/isa/recordisplay.cfm?deid=247492#Download.
    \185\ The Ozone ISA evaluates the evidence associated with 
different ozone related health and welfare effects, assigning one of 
five ``weight of evidence'' determinations: Causal relationship, 
likely to be a causal relationship, suggestive of a causal 
relationship, inadequate to infer a causal relationship, and not 
likely to be a causal relationship. For more information on these 
levels of evidence, please refer to Table II of the ISA.
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b. Visibility
    Visibility can be defined as the degree to which the atmosphere is 
transparent to visible light.\186\ Visibility impairment is caused by 
light scattering and absorption by suspended particles and gases. 
Visibility is important because it has direct significance to people's 
enjoyment of daily activities in all parts of the country. Individuals 
value good visibility for the well-being it provides them directly, 
where they live and work, and in places where they enjoy recreational 
opportunities. Visibility is also highly valued in significant natural 
areas, such as national parks and wilderness areas, and special 
emphasis is given to protecting visibility in these areas. For more 
information on visibility see the final 2009 PM ISA.\187\
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    \186\ National Research Council, (1993). Protecting Visibility 
in National Parks and Wilderness Areas. National Academy of Sciences 
Committee on Haze in National Parks and Wilderness Areas. National 
Academy Press, Washington, DC. This book can be viewed on the 
National Academy Press Web site at http://www.nap.edu/books/0309048443/html/.
    \187\ U.S. EPA. (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F.
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    EPA is working to address visibility impairment. In 1999, EPA 
finalized the regional haze program to protect the visibility in 
Mandatory Class I Federal areas.\188\ There are 156 national parks, 
forests and wilderness areas categorized as Mandatory Class I Federal 
areas.\189\ These areas are defined in CAA section 162 as those 
national parks exceeding 6,000 acres, wilderness areas and memorial 
parks exceeding 5,000 acres, and all international parks which were in 
existence on August 7, 1977. EPA has also concluded that 
PM2.5 causes adverse effects on visibility in other areas 
that are not protected by the Regional Haze Rule, depending on 
PM2.5 concentrations and other factors that control their 
visibility impact effectiveness such as dry chemical composition and 
relative humidity (i.e., an indicator of the water composition of the 
particles). EPA revised the PM2.5 standards in December 2012 
and established a target level of protection that is expected to be met 
through attainment of the existing secondary standards for 
PM2.5.
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    \188\ 64 FR 35714 (July 1, 1999).
    \189\ 62 FR 38680-38681 (July 18, 1997).
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i. Current Visibility Levels
    As mentioned in Section II.B.2.c, millions of people live in 
nonattainment areas for the PM2.5 NAAQS. These populations, 
as well as large numbers of individuals who travel to these areas, are 
likely to experience visibility impairment. In addition, while 
visibility trends have improved in mandatory class I federal areas, the 
most recent data show that these areas continue to suffer from 
visibility impairment. In summary, visibility impairment is experienced 
throughout the U.S., in multi-state regions, urban areas, and remote 
mandatory class I federal areas.
c. Atmospheric Deposition
    Wet and dry deposition of ambient particulate matter delivers a 
complex mixture of metals (e.g., mercury, zinc, lead, nickel, aluminum, 
cadmium), organic compounds (e.g., polycyclic organic matter, dioxins, 
furans) and inorganic compounds (e.g., nitrate, sulfate) to terrestrial 
and aquatic ecosystems. The chemical form of the compounds deposited 
depends on a variety of factors including ambient conditions (e.g., 
temperature, humidity, oxidant levels) and the sources of the material. 
Chemical and physical transformations of the compounds occur in the 
atmosphere as well as the media onto which they deposit. These

[[Page 23440]]

transformations in turn influence the fate, bioavailability and 
potential toxicity of these compounds. Atmospheric deposition has been 
identified as a key component of the environmental and human health 
hazard posed by several pollutants including mercury, dioxin and 
PCBs.\190\
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    \190\ U.S. EPA. (2000). Deposition of Air Pollutants to the 
Great Waters: Third Report to Congress. Office of Air Quality 
Planning and Standards. EPA-453/R-00-0005.
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    Adverse impacts on water quality can occur when atmospheric 
contaminants deposit to the water surface or when material deposited on 
the land enters a waterbody through runoff. Potential impacts of 
atmospheric deposition to waterbodies include those related to both 
nutrient and toxic inputs. Adverse effects to human health and welfare 
can occur from the addition of excess nitrogen via atmospheric 
deposition. The nitrogen-nutrient enrichment contributes to toxic algae 
blooms and zones of depleted oxygen, which can lead to fish kills, 
frequently in coastal waters. Deposition of heavy metals or other 
toxics may lead to the human ingestion of contaminated fish, impairment 
of drinking water, damage to freshwater and marine ecosystem 
components, and limits to recreational uses. Several studies have been 
conducted in U.S. coastal waters and in the Great Lakes Region in which 
the role of ambient PM deposition and runoff is 
investigated.191 192 193 194 195
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    \191\ U.S. EPA. (2004). National Coastal Condition Report II. 
Office of Research and Development/Office of Water. EPA-620/R-03/
002.
    \192\ Gao, Y., E.D. Nelson, M.P. Field, et al. (2002). 
Characterization of atmospheric trace elements on PM2.5 
particulate matter over the New York-New Jersey harbor estuary. 
Atmos. Environ. 36: 1077-1086.
    \193\ Kim, G., N. Hussain, J.R. Scudlark, and T.M. Church. 
(2000). Factors influencing the atmospheric depositional fluxes of 
stable Pb, 210Pb, and 7Be into Chesapeake Bay. J. Atmos. Chem. 36: 
65-79.
    \194\ Lu, R., R.P. Turco, K. Stolzenbach, et al. (2003). Dry 
deposition of airborne trace metals on the Los Angeles Basin and 
adjacent coastal waters. J. Geophys. Res. 108(D2, 4074): AAC 11-1 to 
11-24.
    \195\ Marvin, C.H., M.N. Charlton, E.J. Reiner, et al. (2002). 
Surficial sediment contamination in Lakes Erie and Ontario: A 
comparative analysis. J. Great Lakes Res. 28(3): 437-450.
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    Atmospheric deposition of nitrogen and sulfur contributes to 
acidification, altering biogeochemistry and affecting animal and plant 
life in terrestrial and aquatic ecosystems across the United States. 
The sensitivity of terrestrial and aquatic ecosystems to acidification 
from nitrogen and sulfur deposition is predominantly governed by 
geology. Prolonged exposure to excess nitrogen and sulfur deposition in 
sensitive areas acidifies lakes, rivers and soils. Increased acidity in 
surface waters creates inhospitable conditions for biota and affects 
the abundance and nutritional value of preferred prey species, 
threatening biodiversity and ecosystem function. Over time, acidifying 
deposition also removes essential nutrients from forest soils, 
depleting the capacity of soils to neutralize future acid loadings and 
negatively affecting forest sustainability. Major effects include a 
decline in sensitive forest tree species, such as red spruce (Picea 
rubens) and sugar maple (Acer saccharum), and a loss of biodiversity of 
fishes, zooplankton, and macro invertebrates.
    In addition to the role nitrogen deposition plays in acidification, 
nitrogen deposition also leads to nutrient enrichment and altered 
biogeochemical cycling. In aquatic systems increased nitrogen can alter 
species assemblages and cause eutrophication. In terrestrial systems 
nitrogen loading can lead to loss of nitrogen sensitive lichen species, 
decreased biodiversity of grasslands, meadows and other sensitive 
habitats, and increased potential for invasive species. For a broader 
explanation of the topics treated here, refer to the description in 
Section 6.3.2 of the RIA.
    Adverse impacts on soil chemistry and plant life have been observed 
for areas heavily influenced by atmospheric deposition of nutrients, 
metals and acid species, resulting in species shifts, loss of 
biodiversity, forest decline, damage to forest productivity and 
reductions in ecosystem services. Potential impacts also include 
adverse effects to human health through ingestion of contaminated 
vegetation or livestock (as in the case for dioxin deposition), 
reduction in crop yield, and limited use of land due to contamination.
    Atmospheric deposition of pollutants can reduce the aesthetic 
appeal of buildings and culturally important articles through soiling, 
and can contribute directly (or in conjunction with other pollutants) 
to structural damage by means of corrosion or erosion. Atmospheric 
deposition may affect materials principally by promoting and 
accelerating the corrosion of metals, by degrading paints, and by 
deteriorating building materials such as concrete and limestone. 
Particles contribute to these effects because of their electrolytic, 
hygroscopic, and acidic properties, and their ability to adsorb 
corrosive gases (principally sulfur dioxide).
i. Current Nitrogen and Sulfur Deposition
    Over the past two decades, the EPA has undertaken numerous efforts 
to reduce nitrogen and sulfur deposition across the U.S. Analyses of 
long-term monitoring data for the U.S. show that deposition of both 
nitrogen and sulfur compounds has decreased over the last 19 
years.\196\ The data show that reductions were more substantial for 
sulfur compounds than for nitrogen compounds. In the eastern U.S., 
where data are most abundant, total sulfur deposition decreased by 
about 44 percent between 1990 and 2007, while total nitrogen deposition 
decreased by 25 percent over the same time frame.\197\ These numbers 
are generated by the U.S. national monitoring network and they likely 
underestimate nitrogen deposition because neither ammonia nor organic 
nitrogen is measured. Although total nitrogen and sulfur deposition has 
decreased over time, many areas continue to be negatively impacted by 
deposition. Deposition of inorganic nitrogen and sulfur species 
routinely measured in the U.S. between 2005 and 2007 were as high as 
9.6 kilograms of nitrogen per hectare (kg N/ha) averaged over three 
years and 20.8 kilograms of sulfur per hectare (kg S/ha) averaged over 
three years.\198\
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    \196\ U.S. EPA. (2013). U.S. EPA's Report on the Environment. 
Data accessed online November 25, 2013 at: http://cfpub.epa.gov/eroe/index.cfm?fuseaction=detail.viewInd&lv=list.listBySubTopic&r=216610&subtop=341&ch=46.
    \197\ U.S. EPA. (2012). U.S. EPA's Report on the Environment. 
Data accessed online February 15, 2012 at: http://cfpub.epa.gov/eroe/index.cfm?fuseaction=detail.viewPDF&ch=46&lShowInd=0&subtop=341&lv=list.listByChapter&r=216610.
    \198\ U.S. EPA. (2012). U.S. EPA's Report on the Environment. 
Data accessed online February 15, 2012 at: http://cfpub.epa.gov/eroe/index.cfm?fuseaction=detail.viewPDF&ch=46&lShowInd=0&subtop=341&lv=list.listByChapter&r=216610.
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d. Environmental Effects of Air Toxics
    Emissions from producing, transporting and combusting fuel 
contribute to ambient levels of pollutants that contribute to adverse 
effects on vegetation. Volatile organic compounds, some of which are 
considered air toxics, have long been suspected to play a role in 
vegetation damage.\199\ In laboratory experiments, a wide range of 
tolerance to VOCs has been observed.\200\ Decreases in harvested seed 
pod weight have been reported for the more sensitive plants, and some 
studies have reported effects on seed germination, flowering and fruit 
ripening. Effects of individual VOCs or

[[Page 23441]]

their role in conjunction with other stressors (e.g., acidification, 
drought, temperature extremes) have not been well studied. In a recent 
study of a mixture of VOCs including ethanol and toluene on herbaceous 
plants, significant effects on seed production, leaf water content and 
photosynthetic efficiency were reported for some plant species.\201\
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    \199\ U.S. EPA. (1991). Effects of organic chemicals in the 
atmosphere on terrestrial plants. EPA/600/3-91/001.
    \200\ Cape JN, ID Leith, J Binnie, J Content, M Donkin, M 
Skewes, DN Price, AR Brown, AD Sharpe. (2003). Effects of VOCs on 
herbaceous plants in an open-top chamber experiment. Environ. 
Pollut. 124:341-343.
    \201\ Cape JN, ID Leith, J Binnie, J Content, M Donkin, M 
Skewes, DN Price, AR Brown, AD Sharpe. (2003). Effects of VOCs on 
herbaceous plants in an open-top chamber experiment. Environ. 
Pollut. 124:341-343.
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    Research suggests an adverse impact of vehicle exhaust on plants, 
which has in some cases been attributed to aromatic compounds and in 
other cases to nitrogen oxides.202 203 204
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    \202\ Viskari E-L. (2000). Epicuticular wax of Norway spruce 
needles as indicator of traffic pollutant deposition. Water, Air, 
and Soil Pollut. 121:327-337.
    \203\ Ugrekhelidze D, F Korte, G Kvesitadze. (1997). Uptake and 
transformation of benzene and toluene by plant leaves. Ecotox. 
Environ. Safety 37:24-29.
    \204\ Kammerbauer H, H Selinger, R Rommelt, A Ziegler-Jons, D 
Knoppik, B Hock. (1987). Toxic components of motor vehicle emissions 
for the spruce Picea abies. Environ. Pollut. 48:235-243.
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III. How would this rule reduce emissions and air pollution?

A. Effects of the Vehicle and Fuel Changes on Mobile Source Emissions

    The Tier 3 vehicle and fuel standards will significantly reduce the 
tailpipe and evaporative emissions of light- and heavy-duty vehicles in 
several ways, as described in this section. In addition, the gasoline 
sulfur standard will reduce emissions of SO2 from existing 
gasoline-powered vehicles and equipment. As described in Section II, 
all of these emission reductions will in turn improve air quality 
nationwide and reduce the health effects associated with air pollution 
from mobile sources.
    As with the Tier 2 program, EPA is implementing closely-coordinated 
requirements for both automakers and refiners in the same rulemaking 
action. The Tier 3 vehicle emission standards and gasoline sulfur 
standards represent a ``systems approach'' to reducing vehicle-related 
exhaust and evaporative emissions. By recognizing the relationships 
among the various sources of emissions addressed by this action, we 
have been able to integrate the provisions into a single, coordinated 
program.
1. How do vehicles produce the emissions addressed in this action?
    The degree to which vehicles produce exhaust and evaporative 
emissions depends on the design and functionality of the engine and the 
associated exhaust and evaporative emission controls, in concert with 
the properties of the fuel on which the vehicle is operating. In the 
following paragraphs, we discuss how light- and heavy-duty vehicles 
produce each of these types of emissions, both from the tailpipe and 
from the fuel system.
a. Tailpipe (Exhaust) Emissions
    The pollutants emitted at the vehicle's tailpipe and their 
quantities depend on how the fuel is combusted in the engine and how 
the resulting gases are treated in the exhaust system. Historically, 
much of tailpipe emission control has focused on hydrocarbon compounds 
(HC) and NOX. The portion of hydrocarbons that is methane is 
minimally reactive in forming ozone. Thus, for emission control 
purposes, the focus is generally on non-methane hydrocarbons (NMHC), 
which are also expressed as non-methane organic gases (NMOG) in order 
to account for oxygenates (usually ethanol) now usually present in the 
fuel.
    Tailpipe hydrocarbon emissions also include several toxic 
pollutants, including benzene, acetaldehyde, and formaldehyde. To 
varying degrees, the mass emissions of these pollutants are reduced 
along with other hydrocarbons by the catalytic converter and improved 
engine controls.
    Light- and heavy-duty gasoline vehicles also emit PM and CO. PM 
forms directly as a combustion product (as elemental carbon or soot) 
and indirectly as semi-volatile hydrocarbon compounds that form 
particles in the exhaust system or soon after exiting the tailpipe. CO 
is a product of incomplete fuel combustion.
    When operating properly, modern exhaust emission controls 
(centering on the catalytic convertor) can reduce much of the HC 
(including toxics), NOX and CO exiting the engine. However, 
tailpipe emissions are increased during periods of vehicle startup, as 
catalytic convertors must warm up to be effective; during subsequent 
operation due to the interference of sulfur in the gasoline; during 
high load operating events, as the catalyst is overwhelmed or its 
operation is modified to protect against permanent damage; and as a 
vehicle ages, as the catalyst degrades in performance due to the 
effects of high temperature operation and contaminants in the fuel and 
lubricating oil.
b. Evaporative Emissions
    Gasoline vehicles also produce vapors in the fuel tank and fuel 
system that can be released as evaporative emissions. These vapors are 
primarily the lighter, more volatile hydrocarbon compounds in gasoline. 
As discussed in Section IV below, vehicle evaporative (``evap'') 
control systems are designed to block or capture vapors as they are 
generated. Vapors are generated in the vehicle fuel tank and fuel 
system (and released to the atmosphere if not adequately controlled) as 
fuel heats up due to ambient temperature increase and/or vehicle 
operation. Fuel vapors are also released when they permeate through 
elastomers in the fuel system, when they leak at connections or due to 
damaged components, and during refueling events.
    In general, the evap emission controls on current vehicles (and 
that will be improved under this action) consist of a canister filled 
with activated charcoal and connected by hoses to the fuel system. The 
hoses direct generated vapors to the canister, which collects the 
vapors on the carbon and stores them until the system experiences a 
``purge'' event. During purge, the engine draws fresh air through the 
canister, carrying vapors released by the carbon to the engine to be 
combusted and restoring the capacity of the canister. Evaporative 
emissions occur when vapors are emitted to the atmosphere because the 
evap system is compromised, the carbon canister is overwhelmed, or 
vapors permeate or leak. As such, evaporative emission controls also 
involve proper material selection for fuel system components, careful 
design of these components, and onboard diagnostics to check the system 
for failure.
2. How will the changes to gasoline sulfur content affect vehicle 
emissions?
    Gasoline vehicles rely on highly efficient aftertreatment catalysts 
to control tailpipe emissions of harmful pollutants like CO and 
NOX, as well as VOCs that include air toxics and precursor 
compounds to ozone and secondary PM in the atmosphere. These catalysts 
utilize finely-dispersed precious metals that are susceptible to 
deactivation by sulfur compounds in the exhaust. Studies have 
repeatedly demonstrated that the presence of even a tiny amount of 
sulfur in fuel has a measurable impact on the ability of the catalyst 
to control emissions, and that emission levels of most pollutants, 
especially NOX, are very sensitive to fuel 
sulfur.205 206
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    \205\ The Effects of Ultra-Low Sulfur Gasoline on Emissions from 
Tier 2 Vehicles in the In-Use Fleet, EPA-420-R-14-002.
    \206\ Durbin, T., ``The Effect of Fuel Sulfur on NH3 and Other 
Emissions from 2000-2001 Model Year Vehicles'', May 2003. Published 
as Report E-60 by the Coordinating Research Council, Alpharetta, GA.

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[[Page 23442]]

    Sulfur naturally occurs in crude oil and is carried through the 
refining process into gasoline. EPA's Tier 2 rulemaking for light-duty 
vehicles, published in 2000, required refiners to reduce sulfur levels 
in gasoline to an average of 30 ppm, a reduction of about 90 percent 
from the in-use baseline. At the time, there were indications that 
sulfur reductions below 30 ppm may provide additional emission 
benefits. However, the data was insufficient to quantify the benefits 
to the existing fleet, and the Tier 2 vehicle standards could be 
achieved without lowering sulfur below 30 ppm.\207\
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    \207\ 65 FR 6698 (February 10, 2000).
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    As discussed in Section IV.A.6, subsequent research provides a 
compelling case that even this level of sulfur degrades the emission 
performance of vehicles on the road today and inhibits necessary 
further reductions in vehicle emissions performance, which depend on 
optimum catalyst performance to reach emission targets. A study 
conducted by EPA and the auto industry in support of the Mobile Source 
Air Toxics (MSAT) rule found significant reductions in NOX, 
CO and total HC when nine Tier 2 vehicles were tested on ultra-low 
sulfur fuel.\208\ In particular, the study found a 32 percent decrease 
in NOX when sulfur was reduced from 32 ppm to 6 ppm 
(equivalent to a 25 percent decrease if sulfur levels were reduced from 
30 to 10 ppm, assuming a linear effect). Another recent study by 
Umicore showed reductions of 41 percent for NOX and 17 
percent for hydrocarbons on a PZEV operating on fuel with 33 ppm and 3 
ppm fuel (equivalent to reductions of 27 percent and 11 percent, 
respectively, if sulfur levels were reduced from 30 to 10 ppm, assuming 
a linear effect).\209\
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    \208\ Regulatory Impact Analysis for the Control of Hazardous 
Air Pollutants from Mobile Sources Final Rule, EPA 420-R-07-002, 
Chapter 6.
    \209\ Ball D., Clark D., Moser D. (2011), Effects of Fuel Sulfur 
on FTP NOX Emissions from a PZEV 4 Cylinder Application. 
SAE 2011 World Congress Paper 2011-01-0300.
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    A larger study of Tier 2 vehicles recently completed by EPA 
confirmed these results, showing significant reductions in FTP-
composite NOX (14 percent), CO (10 percent) and total HC (15 
percent) on the 5 ppm fuel, relative to 28 ppm fuel (equivalent to 12 
percent, 9 percent, and 13 percent reduction, respectively, if sulfur 
levels were reduced from 30 to 10 ppm, assuming a linear effect).\210\ 
For NOX, the majority of overall reductions were driven by 
large reductions on warmed-up periods of the test cycle (Bag 2), which 
showed a 52 percent reduction using 5 ppm fuel relative to 28 ppm fuel 
(equivalent to 45 percent reduction if sulfur levels were reduced from 
30 to 10 ppm, assuming a linear effect), consistent with the role of 
sulfur in catalyst degradation discussed above. For additional details 
regarding these results, please see Section IV.A.6.c.
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    \210\ The Effects of Ultra-Low Sulfur Gasoline on Emissions from 
Tier 2 Vehicles in the In-Use Fleet, EPA-420-R-14-002.
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    Our application of these study results assumes a linear effect of 
sulfur level on catalyst efficiency between the high and low sulfur 
test fuels. This is reasonable given that the mass flow rate of sulfur 
in exhaust gas changes in proportion to its concentration in the fuel, 
and that the chemical kinetics of adsorption of sulfur to the precious 
metal sites is approximately first order. Linearity of effect is also 
supported by past studies with multiple fuel sulfur levels such as the 
CRC E-60 and 2000 AAM/AIAM/Oil Industry emission test 
programs.211 212
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    \211\ Durbin, T., ``The Effect of Fuel Sulfur on NH3 and Other 
Emissions from 2000-2001 Model Year Vehicles'', May 2003. Published 
as Report E-60 by the Coordinating Research Council, Alpharetta, GA.
    \212\ ``AAM/AIAM/Oil Industry Low Sulfur & Oxygenate Test 
Program'', 2000, last accessed on 01/15/14 at the following URL: 
http://www.arb.ca.gov/fuels/gasoline/carfg3/aam_prstn.pdf.
---------------------------------------------------------------------------

    Based on these analyses, the benefits of the Tier 3 sulfur standard 
are significant in two ways: They enable vehicles designed to the Tier 
3 tailpipe exhaust standards to meet these standards for the duration 
of their useful life, and they facilitate immediate emission reductions 
from all the vehicles on the road at the time the sulfur controls are 
implemented.

B. How will emissions be reduced?

    The Tier 3 standards will reduce emissions of VOC, NOX 
(including NO2), direct PM2.5, CO, 
SO2, and air toxics. The sulfur standards will reduce 
emissions from the on-road fleet immediately upon implementation in 
calendar year 2017. The vehicle standards will begin to reduce 
emissions as the cleaner cars and trucks begin to enter the fleet in 
model year 2017 and model year 2018, respectively. The magnitude of 
reduction will grow as more Tier 3 vehicles enter the fleet. We present 
emission reductions in calendar year 2018 to reflect the early 
reductions expected from the Tier 3 standards, and in calendar year 
2030, when 70 percent of the miles travelled are from vehicles that 
meet the fully phased-in Tier 3 standards. Although 2030 is the 
farthest year that is feasible for air quality modeling, the full 
reduction of the vehicle program will be realized after 2030, when the 
fleet has fully turned over to vehicles that meet the fully phased-in 
Tier 3 standards; thus we present emission reductions projected in 2050 
as well (see Chapter 7 of the RIA).
    Emission reductions are estimated on an annual basis, for all 50 
U.S. states plus the District of Columbia, Puerto Rico and the U.S. 
Virgin Islands. The reductions were estimated using a version of EPA's 
MOVES model updated for this analysis, as described in detail in 
Chapter 7 of the RIA. This version of MOVES includes our most recent 
data on how vehicle emissions are affected by changes in sulfur, 
ethanol, RVP, and other fuel properties. We estimated emission 
reductions compared to a reference case that assumed renewable fuel 
volumes and ethanol blends based on the U.S. Energy Information 
Administration's Annual Energy Outlook 2013 (AEO2013).\213\ As 
described in Chapter 7 of the RIA, the reference and control scenarios 
based on AEO2013 reflect a mix of E10, E15, and E85 in both 2018 and 
2030. The reference case assumed an average sulfur level of 30 ppm (10 
ppm in California) and continuation of the Tier 2 vehicle program 
indefinitely, with the exception of California and Section 177 states 
that have adopted the LEV III program.
---------------------------------------------------------------------------

    \213\ U.S. Energy Information Administration, Annual Energy 
Outlook (April 15, 2013).
---------------------------------------------------------------------------

    The analysis described here accounts for the following national 
onroad rules:

 Tier 2 Motor Vehicle Emissions Standards and Gasoline Sulfur 
Control Requirements (65 FR 6698, February 10, 2000)
 Heavy-Duty Engine and Vehicle Standards and Highway Diesel 
Fuel Sulfur Control Requirements (66 FR 5002, January 18, 2001)
 Mobile Source Air Toxics Rule (72 FR 8428, February 26, 2007)
 Regulation of Fuels and Fuel Additives: Changes to Renewable 
Fuel Standard Program (75 FR 14670, March 26, 2010)
 Light-Duty Vehicle Greenhouse Gas Emission Standards and 
Corporate Average Fuel Economy Standards for 2012-2016 (75 FR 25324, 
May 7, 2010)
 Greenhouse Gas Emissions Standards and Fuel Efficiency 
Standards for Medium- and Heavy-Duty Engines and Vehicles (76 FR 57106, 
September 15, 2011)
 2017 and Later Model Year Light-Duty Vehicle Greenhouse Gas 
Emissions and Corporate Average Fuel Economy

[[Page 23443]]

Standards (77 FR 62623, October 15, 2012)

The analysis also accounts for many other national rules and standards. 
In addition, the modeling accounts for state and local rules including 
California's most recent Low Emission Vehicle (LEV III) program adopted 
in California and twelve other states (also referred to as Section 177 
states),\214\ local fuel standards, Inspection/Maintenance programs, 
Stage II refueling controls, the National Low Emission Vehicle Program 
(NLEV), and the Section 177 states LEV and LEV II programs. See the 
Tier 3 emissions modeling TSD for more detail.
---------------------------------------------------------------------------

    \214\ These states include Connecticut, Delaware, Maryland, 
Maine, Massachusetts, New Jersey, New York, Oregon, Pennsylvania, 
Rhode Island, Washington, and Vermont.
---------------------------------------------------------------------------

    A summary of emission reductions projected to result from Tier 3, 
relative to the reference case, is shown in calendar years 2018 and 
2030 for NOX, VOC, direct PM2.5, CO, 
SO2, and total air toxics in Table III-1. For many 
pollutants, the immediate reductions in 2018 are significant; for 
example, combined NOX and VOC emissions will be reduced by 
over 300,000 tons. By 2030, combined NOX and VOC emissions 
will be reduced by roughly 500,000 tons, one quarter of the onroad 
inventory. Many of the modeled air toxics will be significantly reduced 
as well, including benzene, 1,3-butadiene, acetaldehyde, acrolein and 
ethanol (ranging from 10 to nearly 30 percent of the national onroad 
inventory by 2030). The relative reduction in overall emissions will 
continue to increase beyond 2030 as more of the fleet continues to turn 
over to Tier 3 vehicles; for example, by 2050, when nearly all of the 
fleet will have turned over to vehicles meeting the fully phased-in 
Tier 3 standards, we estimate the Tier 3 program will reduce onroad 
emissions of NOX and VOC nearly 31 percent from the level of 
emissions projected without Tier 3 controls.

                      Table III-1--Estimated Emission Reductions From the Tier 3 Standards
                                            [Annual U.S. short tons]
----------------------------------------------------------------------------------------------------------------
                                                               2018                            2030
                                                 ---------------------------------------------------------------
                                                                    % of Onroad                     % of Onroad
                                                       Tons          inventory         Tons          inventory
----------------------------------------------------------------------------------------------------------------
NOX.............................................         264,369              10         328,509              25
VOC.............................................          47,504               3         167,591              16
CO..............................................         278,879               2       3,458,041              24
Direct PM2.5....................................             130             0.1           7,892              10
Benzene.........................................           1,916               6           4,762              26
SO2.............................................          14,813              56          12,399              56
1,3-Butadiene...................................             257               5             677              29
Formaldehyde....................................             513               2           1,277              10
Acetaldehyde....................................             600               3           2,067              21
Acrolein........................................              40               3             127              15
Ethanol.........................................           2,704               2          19,950              16
----------------------------------------------------------------------------------------------------------------

    Reductions for each pollutant are discussed in the following 
sections, focusing on the contribution of program elements to the total 
reductions summarized above.
1. NOX
    The Tier 3 sulfur standards will significantly reduce 
NOX emissions immediately upon implementation of the 
program. As discussed above, recent research on the impact of sulfur on 
Tier 2 technology vehicles shows the potential for significant 
reductions in NOX emissions from the existing fleet of Tier 
2 vehicles by lowering sulfur levels to 10 ppm. Prior research shows 
that NOX emissions will also be expected to decrease from 
the fleet of older (pre-Tier 2) light-duty vehicles as well as heavy-
duty gasoline vehicles,\215\ although to a lesser extent than for Tier 
2 vehicles.
---------------------------------------------------------------------------

    \215\ Rao, V. (2001), Fuel Sulfur Effects on Exhaust Emissions: 
Recommendations for MOBILE6, EPA-420-R-01-039.
---------------------------------------------------------------------------

    Table III-2 shows the reduction in NOX emissions, in 
annual short tons, projected in calendar years 2018 and 2030. The 
reductions are split into those attributable to the introduction of low 
sulfur fuel in the pre-Tier 3 fleet (defined for this analysis as model 
years prior to 2017); and reductions attributable to vehicle standards 
enabled by low sulfur fuel (model year 2017 and later). As shown, upon 
implementation of the Tier 3 sulfur standards, total onroad 
NOX emissions are projected to drop 10 percent. This is 
primarily due to large reductions from Tier 2 gasoline vehicles, which 
contribute about one-quarter of the NOX emissions from the 
on-road fleet in 2018. The relative reduction grows as cleaner vehicles 
turn over into the fleet. By 2030, we project that the reduction in 
overall onroad NOX inventory will be 25 percent.

        Table III-2--Projected NOX Reductions From Tier 3 Program
                           [Annual U.S. tons]
------------------------------------------------------------------------
                                           2018               2030
------------------------------------------------------------------------
Total reduction...................            264,369            328,509
Reduction from pre-Tier 3 fleet               242,434             56,324
 due to sulfur standard...........
Reduction from Tier 3 fleet due to             21,934            272,185
 vehicle and sulfur standards.....
Percent reduction in onroad NOX                   10%                25%
 emissions........................
------------------------------------------------------------------------


[[Page 23444]]

2. VOC
    Table III-3 shows the reduction in VOC emissions, in annual short 
tons, projected in calendar years 2018 and 2030 resulting from the Tier 
3 standards. In 2018, as with NOX, we project reductions 
from the pre-Tier 3 fleet with the fuel standards. By 2030, the 
reduction in overall onroad VOC emissions will be 16 percent, the 
majority of this from the vehicles meeting the fully phased-in Tier 3 
standards. The evaporative standards are projected to account for 
roughly one third of the overall vehicle program reduction in 2030.

        Table III-3--Projected VOC Reductions From Tier 3 Program
                           [Annual U.S. tons]
------------------------------------------------------------------------
                                           2018               2030
------------------------------------------------------------------------
Total reduction...................             47,504            167,591
Reduction from pre-Tier 3 fleet                38,786             11,249
 due to sulfur standard...........
Reduction from Tier 3 fleet due to              8,718            156,343
 vehicle and sulfur standards.....
Exhaust...........................             43,009            105,253
Evaporative.......................              4,495             62,339
Percent reduction in onroad VOC                    3%                16%
 emissions........................
------------------------------------------------------------------------

3. CO
    Table III-4 shows the reductions for CO, broken down by pre- and 
post-Tier 3 in the manner described for NOX and VOC above. 
In contrast to NOX and VOC, the immediate CO reductions in 
the onroad fleet from sulfur control in 2018 are small, based on 
research showing that fuel sulfur level has a minimal impact on CO 
emissions from Tier 2 vehicles. The CO exhaust standards are projected 
to reduce onroad CO emissions by 24 percent in 2030.

        Table III-4--Projected CO Reductions From Tier 3 Program
                           [Annual U.S. tons]
------------------------------------------------------------------------
                                           2018               2030
------------------------------------------------------------------------
Total reduction...................            278,879          3,458,041
Reduction from pre-Tier 3 fleet               122,171             17,734
 due to sulfur standard...........
Reduction from Tier 3 fleet due to            156,708          3,440,307
 vehicle and sulfur standards.....
Percent reduction in onroad CO                     2%                24%
 emissions........................
------------------------------------------------------------------------

4. Direct PM2.5
    Reductions in direct emissions of PM2.5 are projected to 
result solely from the vehicle tailpipe standards, so meaningful 
reductions are realized mainly as the fleet turns over. By 2030, we 
project a reduction of about 7,900 tons annually, which represents 
approximately 10 percent of the onroad direct PM2.5 
inventory. The relative reduction in onroad emissions is projected to 
grow to 28 percent in 2050, when nearly all of the fleet will have 
turned over to vehicles meeting the fully phased-in Tier 3 standards. 
Reductions in NOX and VOC emissions will also reduce 
secondary PM formation, which is quantified as part of the air quality 
analysis described in Section III.C.
5. Air Toxics
    Emissions of air toxics also will be reduced by the sulfur, exhaust 
and evaporative standards. Air toxics are generally a subset of 
compounds making up VOC, so the reduction trends tend to track the VOC 
reductions presented above, for most air toxics. Table III-5 presents 
reductions for certain key air toxics, and Table III-6 presents 
reductions for the sum of 71 different toxic compounds.

                            Table III-5--Reductions for Certain Individual Compounds
                                               [Annual U.S. tons]
----------------------------------------------------------------------------------------------------------------
                                                                  % Reduction in                  % Reduction in
                                                   Tons reduced       onroad       Tons reduced       onroad
                                                      in 2018        emissions        in 2030        emissions
----------------------------------------------------------------------------------------------------------------
Benzene.........................................           1,916               6           4,762              26
Acetaldehyde....................................             600               3           2,067              21
Formaldehyde....................................             513               2           1,277              10
1,3-Butadiene...................................             257               5             677              29
Acrolein........................................              40               3             127              15
Naphthalene.....................................              99               3             269              15
Ethanol.........................................           2,704               2          19,950              16
----------------------------------------------------------------------------------------------------------------

    The totals shown in Table III-6 represent the sum of 71 species 
including the toxics in Table III-5, 15 polycyclic aromatic hydrocarbon 
(PAH) compounds in gas and particle phase, and additional gaseous 
compounds such as toluene, xylenes, styrene, hexane, 2,2,4-
trimethylpentane, n-hexane, and propionaldehyde (see Appendix 7A of the 
RIA). As shown, in 2030, the overall onroad inventory of total toxics 
will be reduced by 15 percent, with nearly one

[[Page 23445]]

half of the vehicle program reductions coming from the evaporative 
standards.

        Table III-6--Reductions in Total Mobile Source Air Toxics
                           [Annual U.S. tons]
------------------------------------------------------------------------
                                           2018               2030
------------------------------------------------------------------------
Total reduction...................             15,583             64,558
Reduction from pre-Tier 3 fleet                11,981              3,517
 due to sulfur standard...........
Reduction from Tier 3 fleet due to              3,602             61,041
 vehicle and sulfur standards.....
Exhaust...........................             13,340             34,595
Evaporative.......................              2,243             29,963
Percent reduction in onroad toxics                 3%                15%
 emissions........................
------------------------------------------------------------------------

6. SO2
    SO2 emissions from mobile sources are a direct function 
of sulfur in the fuel, and reducing sulfur in gasoline will result in 
immediate reductions in SO2 from the on and off-road fleet. 
The reductions, shown in Table III-7, are a function of the sulfur 
level and fuel consumption. This is reflected in the relative 
contribution of on-road vehicles and off-road equipment, where off-road 
gasoline consumption accounts for approximately 5 percent of overall 
gasoline use.\216\
---------------------------------------------------------------------------

    \216\ U.S. Energy Information Administration, Annual Energy 
Outlook 2013 (April 15, 2013).

        Table III-7--Projected SO2 Reductions From Tier 3 Program
                           [Annual U.S. tons]
------------------------------------------------------------------------
                                           2018               2030
------------------------------------------------------------------------
Total reduction...................             15,565             13,261
Reduction from onroad vehicles due             14,813             12,399
 to sulfur standard...............
Reduction from off-road equipment                 752                862
 due to sulfur standard...........
Percent reduction in onroad SO2                   56%                56%
 emissions........................
------------------------------------------------------------------------

7. Greenhouse Gases
    Reductions in nitrous oxide (N2O) emissions and methane 
(CH4) emissions, both potent greenhouse gas emissions, are 
projected for gasoline cars and trucks as a result of the sulfur and 
tailpipe standards. A study conducted by the University of California-
Riverside found a 29 percent reduction in N2O emissions over 
the FTP when sulfur was reduced from 30 to 5 ppm,\217\ while EPA 
research described in Section IV.A.6 on sulfur effects found a 26 
percent reduction in CH4 emissions when sulfur was reduced 
from 28 to 5 ppm.\218\
---------------------------------------------------------------------------

    \217\ Huai, et al. (2004), Estimates of the emission rates of 
nitrous oxide from light-duty vehicles using different chassis 
dynamometer test cycles, Atmospheric Environment 6621-6629
    \218\ The Effects of Ultra-Low Sulfur Gasoline on Emissions from 
Tier 2 Vehicles in the In-Use Fleet, EPA-420-R-14-002,
---------------------------------------------------------------------------

    Several studies have established correlations between reductions in 
tailpipe NOX emissions and reductions in N2O from 
gasoline cars and trucks,219 220 221 222 as well as 
correlations between reductions in tailpipe HC emissions and reductions 
in CH4.223 224 Studies by Winer, et al (2005) and 
Behrentz et al (2004) reported N2O: NOX ratios of 
0.06 and 0.095, respectively, and supported the application of 
N2O: NOX ratios to NOX emissions as a 
reasonable method for estimating N2O emission inventories. 
CARB has also used N2O: NOX ratio to develop the 
N2O emissions inventories for the LEV III program, based on 
a regression analysis suggesting N2O: NOX ratio 
of 0.04, on average.\225\
---------------------------------------------------------------------------

    \219\ Michaels, H. (1998) Emissions of Nitrous Oxide from 
Highway Mobile Sources, U.S. EPA EPA420-R-98-009.
    \220\ Behrentz, et al. (2004), Measurements of nitrous oxide 
emissions from light-duty motor vehicles: A pilot study, Atmospheric 
Environment 4291-4303.
    \221\ Meffert, et. al (2000) Analysis of Nitrous Oxide Emissions 
from Light Duty Passenger Cars, SAE 2000-01-1952.
    \222\ Winer, et al. (2005) Estimates of Nitrous Oxide Emissions 
and the Effects of Catalyst Composition and Aging, State of 
California Air Resources Board 02-313.
    \223\ Meszler, D. (2004), Light Duty Vehicle Methane and Nitrous 
Oxide Emissions: Greenhouse Gas Impacts, Study for Northeast States 
Center for a Clean Air Future.
    \224\ Graham, L., Greenhouse Gas Emissions from 1997-2005 Model 
Year Light Duty Vehicles, Environment Canada ERMD Report 
04-44.
    \225\ LEV III Moblie Source Emissions Inventory Technical 
Support Document--Appendix T, January 2012, last accessed on 01/15/
14 at the following URL: http://www.arb.ca.gov/regact/2012/leviiighg2012/levappt.pdf.
---------------------------------------------------------------------------

    As detailed in Chapter 7.3 of the RIA, the N2O 
reductions are estimated by employing two different methodologies, 
resulting in a range of reductions. The first method applies the 
relationship between N2O and NOX from a 
regression model \226\ to NOX inventories from both Tier 3 
and pre-Tier 3 vehicles. The second method applies the regression of 
N2O and NOX only to Tier 3 vehicles and uses the 
UC Riverside sulfur results to estimate the N2O reductions 
from pre-Tier 3 vehicles. Using a 100-year global warming potential of 
298 for N2O according to the 2007 IPCC AR4,\227\ the 
estimated N2O reduction is 2.2 million metric tons of carbon 
dioxide equivalent (MMTCO2e) in 2018, growing to the range 
between 3.8 to 4.0 MMTCO 2e in 2030. For 2018, there was an 
agreement between the two methodologies described above, resulting in a 
single estimate. MOVES can be used to directly estimate CH4 
reductions from the sulfur and vehicle standards, estimating an 
additional 0.1 MMTCO2e

[[Page 23446]]

reduction in 2018, growing to 0.3 MMTCO2e in 2030. The total 
GHG reduction from the Tier 3 rule is 2.3 MMTCO2e in 2018, 
and between 4.1 and 4.3 MMTCO2e in 2030.
---------------------------------------------------------------------------

    \226\ U.S. EPA, 2014, Memorandum to Docket: Regression Analysis 
of Nitrous Oxide and Oxides of Nitrogen from Motor Vehicles.
    \227\ The global warming potentials (GWP) used in this rule are 
consistent with the 100-year time frame values in the 2007 
Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment 
Report (AR4). At this time, the 1996 IPCC Second Assessment Report 
(SAR) 100-year GWP values are used in the official U.S. greenhouse 
gas inventory submission to the United Nations Framework Convention 
on Climate Change (per the reporting requirements under that 
international convention, which were last updated in 2006). 
N2O has a 100-year GWP of 298 and CH4 has a 
100-year GWP of 25 according to the 2007 IPCC AR4.
---------------------------------------------------------------------------

    These reductions will be partially offset by CO2 
emissions associated with higher energy use required in the process of 
removing sulfur within the refinery. As an extension of our refinery-
by-refinery cost modeling described in Section VII.B., we calculated 
the CO2 emission impacts of Tier 3 gasoline sulfur control. 
We estimated refinery-specific changes in process energy and then 
applied emission factors that correspond to those changes, on a 
refinery-by-refinery basis. As described in Chapter 4.5 of the RIA, the 
results showed an increase of up to 1.9 MMTCO2e in 2018 and 
1.6 MMTCO2e in 2030 for all U.S. refineries complying with 
the lower sulfur standards assuming that the sulfur standards are fully 
phased-in. In 2018, the combined impact of CH4 and 
N2O emission reductions from the vehicles and CO2 
emission increases from the refineries shows a slight net decrease on a 
CO2 equivalent basis. While still small, this net decrease 
grows to a range between 2.5 to 2.7 MMTCO2e by 2030.
    We do not expect the Tier 3 vehicle standards to result in any 
discernible changes in vehicle CO2 emissions or fuel 
economy. Emissions of the pollutants that are controlled by the Tier 3 
program--NMOG, NOX, and PM--are not a function of the amount 
of fuel consumed, since manufacturers need to design their catalytic 
emission control systems to reduce these emissions regardless of their 
engine-out levels.

C. How will air pollution be reduced?

    Reductions in emissions of NOX, VOC, PM2.5 
and air toxics expected as a result of the Tier 3 standards are 
projected to lead to significant improvements in air quality. The air 
quality modeling predicts significant improvements in ozone 
concentrations due to the Tier 3 standards. Ambient PM2.5 
and NO2 concentrations are also expected to improve as a 
result of the Tier 3 program. Decreases in ambient concentrations of 
air toxics are projected with the Tier 3 standards, including notable 
nationwide reductions in benzene concentrations. Our air quality 
modeling also predicts improvements in visibility and sulfur 
deposition, as well as substantial decreases in nitrogen deposition as 
a result of the Tier 3 standards. The results of our air quality 
modeling of the impacts of the Tier 3 rule are summarized in the 
following section.
1. Ozone
    The air quality modeling done for this action projects that in 
2018, with all current and required controls in effect but excluding 
the emissions changes expected to occur as a result of the Tier 3 
standards or any other additional controls, at least 19 counties, with 
a projected population of over 37 million people, would have projected 
design values above the level of the 2008 8-hour ozone standard of 75 
ppb. In 2030 the modeling projects that in the absence of Tier 3 
standards or any other additional controls there will be 6 counties 
with a population of over 19 million people with projected design 
values above the level of the 2008 8-hour ozone standard of 75 ppb. An 
additional 37 million people will be living in the 43 counties that 
will be close to (within 10 percent of) the level of the ozone 
standard.
    Air quality modeling indicates that this action will meaningfully 
decrease ozone design value concentrations in many areas of the 
country, including those that are projected to be exceeding, or close 
to exceeding, the ozone standard. In 2018, the majority of the design 
value decreases are between 0.5 and 1.0 ppb. In 2030, the Tier 3 rule 
will result in larger decreases in ozone design values, with the 
majority of counties projecting decreases of between 0.5 and 1.0 ppb, 
and over 250 more counties with decreases greater than 1.0 ppb. Since 
the Tier 3 standards go into effect during the period when some areas 
are still working to attain the ozone NAAQS, the projected air quality 
changes will help state and local agencies in their effort to attain 
and maintain the ozone standard.
2. Particulate Matter
    The air quality modeling conducted for this action projects that in 
2018, with all current controls in effect but excluding the emissions 
changes expected to occur as a result of Tier 3 standards or any other 
additional controls, at least 14 counties, with a projected population 
of over 20 million people, would have projected design values above the 
level of the annual standard of 12 [mu]g/m\3\ and at least 24 counties, 
with a projected population of over 18 million people, would have 
projected design values above the level of the 24-hour standard of 35 
[mu]g/m\3\. In 2030, the modeling projects that in the absence of Tier 
3 standards or any other additional controls there will be 13 counties, 
with a projected population of over 21 million people, with projected 
design values above the level of the annual standard of 12 [mu]g/m\3\ 
and 18 counties, with a projected population of over 12 million people, 
with projected design values above the level of the 24-hour standard of 
35 [mu]g/m\3\. Since the Tier 3 standards go into effect during the 
period when some areas are still working to attain the 2006 and 2012 
PM2.5 NAAQS, the projected air quality changes will be 
useful to state and local agencies in their effort to attain and 
maintain the PM2.5 standards.
    The Tier 3 standards will reduce 24-hour and annual 
PM2.5 design values due to projected tailpipe reductions in 
primary PM2.5, SO2, NOX and VOCs from 
reductions in fuel sulfur and engine controls. In 2018 the standards 
will have a small impact on annual PM2.5 design values in 
the majority of modeled counties. However, in over 200 counties annual 
PM2.5 design values are projected to decrease by greater 
than 0.01 [mu]g/m\3\. In 2030 annual PM2.5 design values in 
the majority of modeled counties will decrease by between 0.01 and 0.05 
[mu]g/m\3\ and in over 140 additional counties design values are 
projected to decrease by greater than 0.05 [mu]g/m\3\. In addition, in 
2018 24-hour PM2.5 design values in over 200 counties are 
projected to decrease by between 0.05 and 0.15 [mu]g/m\3\ and in 2030 
24-hour PM2.5 design values in over 180 counties decrease by 
at least 0.15 [mu]g/m\3\.
3. Nitrogen Dioxide
    Although our modeling indicates that by 2030 the majority of the 
country will experience decreases of less than 0.1 ppb in their annual 
NO2 concentrations due to this rule, annual NO2 
concentrations are projected to decrease by more than 0.3 ppb in most 
urban areas. These emissions reductions would also likely decrease 1-
hour NO2 concentrations and help any potential nonattainment 
areas to attain and maintain the standard. Additional information on 
the emissions reductions that are projected with this rule is available 
in Section 7.2.1 of the RIA.
4. Air Toxics
    Our modeling indicates that the impacts of final Tier 3 standards 
include notable nationwide reductions in benzene and generally small 
decreases in ambient concentrations of other air toxics, mainly in 
urban areas. Although reductions are greater in 2030 (when 70 percent 
of the miles travelled are from vehicles that meet the fully phased-in 
Tier 3 standards) than in 2017 (the first year of the final program), 
our modeling projects there will be small immediate reductions in 
ambient concentrations of air toxics due to the Tier 3 sulfur controls. 
Furthermore, the full reduction of the vehicle program will be realized

[[Page 23447]]

after 2030, when the fleet has fully turned over to vehicles meeting 
the fully phased-in Tier 3 standards. Air toxics pollutants dominated 
by primary emissions (or a decay product of a directly emitted 
pollutant), such as benzene, are impacted more than air toxics that 
primarily result from photochemical transformation.
    Specifically, in 2030, our modeling projects that the Tier 3 rule 
will decrease ambient benzene concentrations across much of the country 
on the order of 1 to 5 percent, with reductions ranging from 10 to 25 
percent in some urban areas. Our modeling also shows reductions of 1,3-
butadiene and acrolein concentrations in 2030 ranging between 1 and 25 
percent and 1 and 10 percent respectively, with 1,3-butadiene decreases 
of at least 0.005 [mu]g/m\3\ in urban areas. These toxics are national 
risk drivers and the reductions in ambient concentrations from this 
rule will result in reductions in risks from cancer and noncancer 
health effects. In some parts of the country (mainly urban areas), 
ethanol and formaldehyde concentrations are projected to decrease on 
the order of 1 to 10 percent and 1 to 2.5 percent respectively in 2030 
as a result of the Tier 3 rule. Decreases in ethanol concentrations are 
expected due to reductions in VOC as a result of the Tier 3 standards. 
Changes in ambient acetaldehyde concentrations are generally less than 
1 percent across the U.S., although the Tier 3 rule may decrease 
acetaldehyde concentrations in some urban areas by 1 to 2.5 percent in 
2030. Changes in ambient naphthalene concentrations are generally 
between 1 and 10 percent in 2030 with absolute decreases of up to 0.005 
[mu]g/m\3\.
    Although the reductions in ambient air toxics concentrations 
expected from the Tier 3 standards are generally small, they are 
projected to benefit the majority of the U.S. population. As shown in 
Table III-8, over 75 percent of the total U.S. population is projected 
to experience a decrease in ambient benzene and 1,3-butadiene 
concentrations of at least 1 percent. Over 60 percent of the U.S 
population is projected to experience at least a 1 percent decrease in 
ambient ethanol and acrolein concentrations, and over 35 percent would 
experience a similar decrease in ambient formaldehyde concentrations 
with the Tier 3 standards.

  Table III-8--Percent of Total Population Experiencing Changes in Annual Ambient Concentrations of Toxic Pollutants in 2030 as a Result of the Tier 3
                                                                        Standards
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              Benzene        Acrolein      1,3-Butadiene   Formaldehyde       Ethanol      Acetaldehyde     Naphthalene
        Percent change (percent)             (percent)       (percent)       (percent)       (percent)       (percent)       (percent)       (percent)
--------------------------------------------------------------------------------------------------------------------------------------------------------
<=-50...................................  ..............  ..............  ..............  ..............  ..............  ..............  ..............
>-50 to <=-25...........................  ..............  ..............  ..............  ..............  ..............  ..............  ..............
>-25 to <=-10...........................            2.29            0.75           19.07  ..............  ..............  ..............           10.74
>-10 to <=-5............................           20.63           12.72           27.29  ..............            5.39  ..............           31.56
>-5 to <=-2.5...........................           27.50           25.17           15.37            0.60           24.08  ..............           20.58
>-2.5 to <=-1...........................           28.60           24.62           18.33           35.34           34.10           11.77           14.98
>-1 to <1...............................           20.97           36.74           19.93           64.06           36.43           88.23           22.14
>=1 to <2.5.............................  ..............  ..............  ..............  ..............  ..............  ..............  ..............
>=2.5 to <5.............................  ..............  ..............  ..............  ..............  ..............  ..............  ..............
>=5 to <10..............................  ..............  ..............  ..............  ..............  ..............  ..............  ..............
>=10 to <25.............................  ..............  ..............  ..............  ..............  ..............  ..............  ..............
>=25 to <50.............................  ..............  ..............  ..............  ..............  ..............  ..............  ..............
>=50....................................  ..............  ..............  ..............  ..............  ..............  ..............  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------

    In addition, as described in Section 7.2.4.4.2 of the RIA, our 
modeling projects that acrolein concentrations would decrease to levels 
below the inhalation reference concentration for acrolein (0.02 [mu]g/
m\3\) for over 5 million people in 2030, meaning that as a result of 
the Tier 3 standards, 5 million fewer Americans will be exposed to 
ambient levels of acrolein high enough to present a potential for 
adverse health effects.
5. Visibility
    Air quality modeling conducted for this final action was used to 
project visibility conditions in 137 mandatory class I federal areas 
across the U.S. The results show that in 2030 all the modeled areas 
will continue to have annual average deciview levels above background 
and the Tier 3 rule will improve visibility in all these areas.\228\ 
The average visibility at all modeled mandatory class I federal areas 
on the 20 percent worst days is projected to improve by 0.02 deciviews, 
or 0.16 percent, in 2030. Section 7.2.5.5 of the RIA contains more 
detail on the visibility portion of the air quality modeling.
---------------------------------------------------------------------------

    \228\ The level of visibility impairment in an area is based on 
the light-extinction coefficient and a unitless visibility index, 
called a ``deciview,'' which is used in the valuation of visibility. 
The deciview metric provides a scale for perceived visual changes 
over the entire range of conditions, from clear to hazy. Under many 
scenic conditions, the average person can generally perceive a 
change of one deciview. The higher the deciview value, the worse the 
visibility. Thus, an improvement in visibility is a decrease in 
deciview value.
---------------------------------------------------------------------------

6. Nitrogen and Sulfur Deposition
    Our air quality modeling projects substantial decreases in nitrogen 
deposition as a result of the Tier 3 standards. The standards will 
result in annual percent decreases of greater than 2.5 percent in most 
major urban areas and greater than 5 percent in a few areas. In 
addition, smaller decreases, in the 1 to 2.5 percent range, will occur 
over much of the rest of the country. The impacts of the Tier 3 
standards on sulfur deposition are smaller, ranging from no change to 
decreases of over 2.5 percent in some areas. For maps of 2030 
deposition impacts and additional information on these impacts see 
Section 7.2.5.6 of the RIA.
7. Environmental Justice
    Environmental justice (EJ) is a principle asserting that all people 
deserve fair treatment and meaningful involvement with respect to 
environmental laws, regulations, and policies. EPA seeks to provide the 
same degree of protection from environmental health hazards for all 
people. As referenced below, numerous studies have found that some 
environmental hazards are more prevalent in areas with high population 
fractions of racial/ethnic minorities and people with low socioeconomic 
status (SES), as would be expected on the basis of those areas' share 
of the general population.
    As discussed in Section II of this document, concentrations of many 
air pollutants are elevated near high-traffic

[[Page 23448]]

roadways. If minority populations and low-income populations 
disproportionately live near such roads, then an issue of EJ may be 
present. Such disparities may be due to multiple factors.\229\
---------------------------------------------------------------------------

    \229\ Depro, B.; Timmins, C. (2008) Mobility and environmental 
equity: Do housing choices determine exposure to air pollution? 
North Caroline State University Center for Environmental and 
Resource Economic Policy.
---------------------------------------------------------------------------

    People with low SES often live in neighborhoods with multiple 
stressors and health risk factors, including reduced health insurance 
coverage rates, higher smoking and drug use rates, limited access to 
fresh food, visible neighborhood violence, and elevated rates of 
obesity and some diseases such as asthma, diabetes, and ischemic heart 
disease. Although questions remain, several studies find stronger 
associations between air pollution and health in locations with such 
chronic neighborhood stress, suggesting that populations in these areas 
may be more susceptible to the effects of air 
pollution.230 231 232 233 Household-level stressors such as 
parental smoking and relationship stress also may increase 
susceptibility to the adverse effects of air 
pollution.234 235
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    \230\ Clougherty, J.E.; Kubzansky, L.D. (2009) A framework for 
examining social stress and susceptibility to air pollution in 
respiratory health. Environ Health Perspect 117: 1351-1358. 
Doi:10.1289/ehp.0900612 [Online at http://dx.doi.org].
    \231\ Clougherty, J.E.; Levy, J.I.; Kubzansky, L.D.; Ryan, P.B.; 
Franco Suglia, S.; Jacobson Canner, M.; Wright, R.J. (2007) 
Synergistic effects of traffic-related air pollution and exposure to 
violence on urban asthma etiology. Environ Health Perspect 115: 
1140-1146. doi:10.1289/ehp.9863 [Online at http://dx.doi.org].
    \232\ Finkelstein, M.M.; Jerrett, M.; DeLuca, P.; Finkelstein, 
N.; Verma, D.K.; Chapman, K.; Sears, M.R. (2003) Relation between 
income, air pollution and mortality: a cohort study. Canadian Med 
Assn J 169: 397-402.
    \233\ Shankardass, K.; McConnell, R.; Jerrett, M.; Milam, J.; 
Richardson, J.; Berhane, K. (2009) Parental stress increases the 
effect of traffic-related air pollution on childhood asthma 
incidence. Proc Natl Acad Sci 106: 12406-12411. doi:10.1073/
pnas.0812910106 [Online at http://dx.doi.org].
    \234\ Lewis, A.S.; Sax, S.N.; Wason, S.C.; Campleman, S.L (2011) 
Non-chemical stressors and cumulative risk assessment: An overview 
of current initiatives and potential air pollutant interactions. Int 
J Environ Res Public Health 8: 2020-2073. Doi:10.3390/ijerph8062020 
[Online at http://dx.doi.org].
    \235\ Rosa, M.J.; Jung, K.H.; Perzanowski, M.S.; Kelvin, E.A.; 
Darling, K.W.; Camann, D.E.; Chillrud, S.N.; Whyatt, R.M.; Kinney, 
P.L.; Perera, F.P.; Miller, R.L (2010) Prenatal exposure to 
polycyclic aromatic hydrocarbons, environmental tobacco smoke and 
asthma. Respir Med (In press). doi:10.1016/j.rmed.2010.11.022 
[Online at http://dx.doi.org].
---------------------------------------------------------------------------

    To address the existing conditions in areas near major roadways, in 
comparison with other locations, we reviewed existing scholarly 
literature examining the topic, and conducted our own evaluation of two 
national datasets: The U.S. Census Bureau's American Housing Survey for 
calendar year 2009 and the U.S. Department of Education's database of 
school locations.
    Existing publications that address EJ issues generally report that 
populations living near major roadways (and other types of 
transportation infrastructure) tend to be composed of larger fractions 
of nonwhite residents. People living in neighborhoods near such sources 
of air pollution also tend to be lower in income than people living 
elsewhere. Numerous studies evaluating the demographics and 
socioeconomic status of populations or schools near roadways have found 
that they include a greater percentage of minority residents, as well 
as lower SES (indicated by variables such as median household income). 
Locations in these studies include Los Angeles, CA; Seattle, WA; Wayne 
County, MI; Orange County, FL; and the State of California 
236 237 238 239 240 241
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    \236\ Marshall, J.D. (2008) Environmental inequality: Air 
pollution exposures in California's South Coast Air Basin.
    \237\ Su, J.G.; Larson, T.; Gould, T.; Cohen, M.; Buzzelli, M. 
(2010) Transboundary air pollution and environmental justice: 
Vancouver and Seattle compared. GeoJournal 57: 595-608. doi:10.1007/
s10708-009-9269-6 [Online at http://dx.doi.org].
    \238\ Chakraborty, J.; Zandbergen, P.A. (2007) Children at risk: 
Measuring racial/ethnic disparities in potential exposure to air 
pollution at school and home. J Epidemiol Community Health 61: 1074-
1079. doi: 10.1136/jech.2006.054130 [Online at http://dx.doi.org].
    \239\ Green, R.S.; Smorodinsky, S.; Kim, J.J.; McLaughlin, R.; 
Ostro, B. (2003) Proximity of California public schools to busy 
roads. Environ Health Perspect 112: 61-66. doi:10.1289/ehp.6566 
[http://dx.doi.org].
    \240\ Wu, Y; Batterman, S.A. (2006) Proximity of schools in 
Detroit, Michigan to automobile and truck traffic. J Exposure Sci & 
Environ Epidemiol. doi:10.1038/sj.jes.7500484 [Online at http://dx.doi.org].
    \241\ Su, J.G.; Jerrett, M.; de Nazelle, A.; Wolch, J. (2011) 
Does exposure to air pollution in urban parks have socioeconomic, 
racial, or ethnic gradients? Environ Res 111: 319-328.
---------------------------------------------------------------------------

    More recently, three publications report nationwide analyses that 
compare the demographic patterns of people who do or do not live near 
major roadways.242 243 244 All three of these studies found 
that people living near major roadways are more likely to be minorities 
or low in SES. They also found that the outcomes of their analyses 
varied between regions within the U.S. However, only one such study 
looked at whether such conclusions were confounded by living in a 
location with higher population density and how demographics differ 
between locations nationwide. In general, it found that higher density 
areas have higher proportions of low income and minority residents.
---------------------------------------------------------------------------

    \242\ Rowangould, G.M. (2013) A census of the US near-roadway 
population: Public health and environmental justice considerations. 
Transportation Research Part D; 59-67.
    \243\ Tian, N.; Xue, J.; Barzyk. T.M. (2013) Evaluating 
socioeconomic and racial differences in traffic-related metrics in 
the United States using a GIS approach. J Exposure Sci Environ 
Epidemiol 23: 215-222.
    \244\ Boehmer, T.K.; Foster, S.L.; Henry, J.R.; Woghiren-
Akinnifesi, E.L.; Yip, F.Y. (2013) Residential proximity to major 
highways--United States, 2010. Morbidity and Mortality Weekly Report 
62(3): 46-50.
---------------------------------------------------------------------------

    We analyzed two national databases that allowed us to evaluate 
whether homes and schools were located near a major road. One database, 
the American Housing Survey (AHS), includes descriptive statistics of 
over 70,000 housing units across the nation. The study is conducted 
every two years by the U.S. Census Bureau. We analyzed data from the 
2009 AHS. The second database we analyzed was the U.S. Department of 
Education's Common Core of Data, which includes enrollment and location 
information for schools across the U.S.
    In analyzing the 2009 AHS, we focused on whether or not a housing 
unit was located within 300 feet of ``4-or-more lane highway, railroad, 
or airport.'' \245\ We analyzed whether there were differences between 
houses and householders in such locations and those not in them.\246\ 
We included other variables, such as land use category, region of 
country, and housing type. We found that homes with a nonwhite 
householder were 22-34 percent more likely to be located within 300 
feet of these large transportation facilities, while homes with a 
Hispanic householder were 17-33 percent more likely. Households near 
large transportation facilities were, on average, lower in income and 
educational attainment, more likely to be a rental property and located 
in an urban area.
---------------------------------------------------------------------------

    \245\ This variable primarily represents roadway proximity. 
According to the Central Intelligence Agency's World Factbook, in 
2010, the United States had 6,506,204 km or roadways, 224,792 km of 
railways, and 15,079 airports. Highways thus represent the 
overwhelming majority of transportation facilities described by this 
factor in the AHS.
    \246\ Bailey, C. (2011) Demographic and Social Patterns in 
Housing Units Near Large Highways and other Transportation Sources. 
Memorandum to docket.
---------------------------------------------------------------------------

    In examining schools near major roadways, we examined the Common 
Core of Data (CCD) from the U.S. Department of Education, which 
includes information on all public elementary and secondary schools and 
school districts nationwide.\247\ To determine school proximities to 
major roadways, we used a geographic

[[Page 23449]]

information system (GIS) to map each school and roadways based on the 
U.S. Census's TIGER roadway file.\248\ We found that minority students 
were overrepresented at schools within 200 meters of the largest 
roadways, and that schools within 200 meters of the largest roadways 
also had higher than expected numbers of students eligible for free or 
reduced-price lunches. For example, Black students represent 21.57 
percent of students at schools located within 200 meters of a primary 
road, whereas Black students represent 16.62 percent of students in all 
U.S. schools. Hispanic students represent 30.13 percent of students at 
schools located within 200 meters of a primary road, whereas Hispanic 
students represent 21.93 percent of students in all U.S. schools.
---------------------------------------------------------------------------

    \247\ http://nces.ed.gov/ccd/.
    \248\ Pedde, M.; Bailey, C. (2011) Identification of Schools 
within 200 Meters of U.S. Primary and Secondary Roads. Memorandum to 
the docket.
---------------------------------------------------------------------------

    Overall, there is substantial evidence that people who live or 
attend school near major roadways are more likely to be of a minority 
race, Hispanic ethnicity, and/or low SES. The emission reductions from 
this rule are projected to result in widespread air quality 
improvements, but the impact on pollution levels in close proximity to 
roadways is expected to be most direct. Thus, this rule is likely to 
help in mitigating the disparity in racial, ethnic, and economically-
based exposures.

IV. Vehicle Emissions Program

    In the 14 years since EPA finalized the Tier 2 Vehicle Program, 
manufacturers of light-duty vehicles have continued to develop a wide 
range of improved technologies capable of reducing emissions, 
especially exhaust hydrocarbons, nitrogen oxides (NOX), and 
particulate matter (PM), and evaporative hydrocarbons. The California 
LEV II program has been instrumental in the auto industry's continuous 
technology improvements by requiring year after year reductions in 
fleet average exhaust hydrocarbon levels. In addition, California set 
performance standards that have resulted in the introduction of 
advanced exhaust and evaporative emission controls in partial zero 
emission vehicles (PZEVs). Overall, this progress in vehicle technology 
has made it possible for manufacturers to achieve emission reductions 
with a number of today's vehicles that go well beyond the requirements 
of the Tier 2 program.
    Extensive data from existing Tier 2 (and California LEV II) 
vehicles presented in the NPRM and received since the proposal have 
demonstrated the potential for further significant reductions. For 
exhaust emissions, these opportunities include addressing: Emissions 
produced at start-up; emissions under high-speed, high-load conditions; 
the effects of sulfur in gasoline; the effects of increased oil 
consumption; and the effects of age on vehicles and control systems. In 
addition, technologies now exist that have inherently low evaporative 
emission characteristics and demonstrate improved in-use durability. 
Based on this body of data, we are adopting more stringent standards 
designed to reduce emissions, primarily exhaust non-methane organic 
gases (NMOG), NOX, and PM and evaporative hydrocarbon 
emissions from new vehicles. As discussed in detail below and in the 
final RIA, we have concluded that, in conjunction with the reductions 
in fuel sulfur also required in this action, the new vehicle emissions 
standards are feasible, accounting for costs, across the fleet in the 
timeframe of the program. We believe that simultaneous reductions in 
fuel sulfur will be a key factor in enabling the entire fleet of 
vehicles subject to Tier 3 to meet the new emission standards in-use, 
throughout the life of the vehicles (see Section IV.A.6 below).
    We received a large number and wide range of comments on the 
proposed vehicle emission program, and we have carefully considered all 
of them. (The Summary and Analysis of Comments document addresses the 
comments received; it is located in the docket for this rulemaking and 
also on EPA's Web site at www.epa.gov/otaq/tier3.htm.) With very few 
exceptions, we are finalizing the Tier 3 vehicle emission program as 
proposed, including the levels of the new emission standards and the 
phase-in schedules. In several cases, as discussed in detail below, the 
comments and/or newer technical information have resulted in 
adjustments to the proposed program, including when the requirements 
begin, what fuel is used for vehicle compliance testing, and what the 
PM standard level is for testing under aggressive driving conditions. 
The final Tier 3 vehicle provisions, like the proposal, also harmonize 
closely with California's LEV III program.
    This section describes in detail the program for reducing tailpipe 
and evaporative emissions from light-duty vehicles (LDVs, or passenger 
cars), light-duty trucks (LDT1s, 2s, 3s, and 4s), Medium-Duty Passenger 
Vehicles (MDPVs), and certain heavy-duty vehicles (HDVs). Sections IV.A 
and IV.B discuss the tailpipe emission standards and time lines, and 
other provisions for new LDVs, LDTs, and MDPVs and for new heavy-duty 
vehicles up to 14,000 lbs Gross Vehicle Weight Rating (GVWR). Section 
IV.C presents the new Tier 3 evaporative emissions standards and 
program and Section IV.D describes the new evaporative emissions leak 
test. Section IV.E presents improvements to the existing Onboard 
Diagnostics (OBD) provisions. In Section IV.F, we describe new 
provisions to update our federal certification fuel to better match 
today's in-use fuel. We also discuss in this section the compliance 
flexibilities for small auto manufacturing companies and small-volume 
manufacturers (IV.G) as well as new testing and test procedure 
provisions and other compliance provisions (IV.H).

A. Tier 3 Tailpipe Emission Standards for Light-Duty Vehicles, Light-
Duty Trucks, and Medium-Duty Passenger Vehicles

1. How the Tier 3 Program Is Harmonized With the California LEV III 
Program
    In describing the Tier 3 program for light- and heavy-duty vehicles 
in this preamble, we discuss how the provisions are consistent with the 
California Air Resources Board (CARB) LEV III program.\249\ During the 
development of the proposed rule and in their comments, auto 
manufacturers stressed to us the importance of their being able to 
design and produce a single fleet of vehicles for all 50 states that 
simultaneously complies with requirements under the Tier 3 program and 
the LEV III program, as well as greenhouse gas/CAFE requirements they 
are facing in the same timeframe. To the extent that the federal and 
California programs are consistent, special versions of vehicles with 
different emission control hardware and calibrations for different 
geographic areas will be unnecessary. This will allow manufacturers to 
avoid the additional costs of parallel design, development, 
calibration, and manufacturing. Consistency among programs also 
eliminates the need to supply aftermarket parts for repair of multiple 
versions of a vehicle. We believe that the most effective and efficient 
national program will result from close coordination between CARB LEV 
III and federal Tier 3 program elements and their implementation.
---------------------------------------------------------------------------

    \249\ See California Low-Emission Vehicles (LEV) & GHG 2012 
regulations adopted by the State of California Air Resources Board, 
March 22, 2012, Resolution 12-21 incorporating by reference 
Resolution 12-11, which was adopted January 26, 2012. Available at 
http://www.arb.ca.gov/regact/2012/leviiighg2012/leviiighg2012.htm 
(last accessed December 2, 2013).

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[[Page 23450]]

    To that end, we worked closely with CARB and the vehicle 
manufacturers, the latter both individually and through their trade 
associations, to align the two programs. The Tier 3 program is 
identical to LEV III in most major respects for light-duty vehicles 
(and heavy-duty vehicles, as described in sections below). The levels 
and the timing of the declining fleet-average NMOG+NOX 
standards are identical to those in LEV III. The Tier 3 emissions bins 
to which manufacturers will certify individual vehicle models in order 
to comply with the fleet-average standards, are also identical to those 
in LEV III. Similarly, the light-duty Tier 3 FTP PM standards and 
percent phase-in match those for LEV III through MY 2024.
    We note there are a few light-duty Tier 3 and LEV III provisions 
that are different, for reasons discussed below. For example, the LEV 
III program and the Tier 3 program have different light-duty PM 
requirements late in the program (i.e., after MY 2024 (IV.A.3.b.)), and 
the two programs have different final NMOG+NOX standards for 
small volume manufacturers (IV.G.1). As also discussed below, we are 
finalizing a revised SFTP (US06) PM standard, and CARB has commented 
that it plans to take similar action in near future. CARB also 
indicated in their comments that they intend to consider several 
additional actions to further align several minor aspects of LEV III 
with the Tier 3 program once Tier 3 is finalized.
    Beyond the provisions mentioned above, the differences between the 
programs are not major and most will exist only in the transitional 
years of the Tier 3 program. These additional differences result from 
the fact that the LEV III requirements begin slightly earlier and that 
a limited phase-in of some provisions is necessary for a smooth 
transition to overall aligned programs. These temporary differences 
include the process for how early compliance credits are generated and 
used (e.g., Section IV.A.7.a); how quickly manufacturers will need to 
move toward certifying all of their vehicle models to longer useful-
life values (e.g., Section IV.A.7.c) and on the new test fuel (e.g., 
Section IV.A.7.d); and transitional emissions bins to facilitate the 
transition from Tier 2 to Tier 3 (Section IV.A.7.n).
2. Summary of the Tier 3 FTP and SFTP Tailpipe Standards
a. Major Comments on and Significant Changes to the Proposal
    As mentioned above, we are finalizing most aspects of the 
comprehensive Tier 3 vehicle program as we proposed them. The levels of 
the FTP and SFTP standards for the key tailpipe pollutants of concern--
the sum of NMOG and NOX emissions, expressed as 
NMOG+NOX, and PM--are the same as proposed (except for the 
numerically lower final PM SFTP (US06) standard, as discussed below). 
In addition, the timing of the requirements remains the same as in the 
NPRM, starting with MY2017 and MY2018 and phasing in according to the 
same declining fleet-average schedule for the NMOG+NOX 
standards and the same percent-of-sales phase-in schedule for the PM 
standards. We continue to believe that these elements form a robust 
framework for the Tier 3 vehicle program and closely harmonize with the 
respective elements of California's LEV III program.
    There are several important provisions of the light-duty Tier 3 
program that we have revised from the proposal, based on further 
consideration and information that we received from commenters. We 
discuss each of these in detail later in this section and summarize 
them here.
     As described below in Section IV.A.2.c, each of the four 
primary Tier 3 emission standards has an associated alternative phase-
in option for heavier light-duty vehicles that a manufacturer can 
choose if it prefers a later start date (to provide 4 years of lead 
time) and a stable standard.\250\ We proposed that a manufacturer 
choosing these options be required to apply the alternative phase-in 
schedule to its entire light-duty fleet. In response to comments from 
automakers that this restriction would be unnecessarily burdensome, we 
reconsidered this provision. For the reasons discussed below, we are 
allowing a manufacturer to apply the alternative phase-in schedules to 
only their heavier light-duty vehicles, instead of their entire light-
duty fleet. However, manufacturers have largely indicated that they 
plan on adopting the primary program which is harmonized with LEV III.
---------------------------------------------------------------------------

    \250\ In this preamble, ``heavier light-duty vehicles'' refers 
to LDVs and LDTs greater than 6,000 lbs GVWR and MDPVs, and 
``lighter light-duty vehicles'' refers to LDVs and LDTs up to 6,000 
lbs GVWR.
---------------------------------------------------------------------------

     This Tier 3 rule provides an opportunity for EPA to 
reassess the degree to which the gasoline used for vehicle emissions 
testing and certification reflects in-use gasoline around the country. 
In the case of ethanol content, we proposed that the emissions test 
fuel contain 15 percent ethanol (E15), anticipating a significant shift 
to higher ethanol content in use in the near future. For several 
reasons described below (Section IV.F.1), this shift in in-use fuel is 
not materializing as quickly as expected, and E10 continues to be 
almost universal today. We received a near consensus among comments 
from stakeholders that E10 test fuel is more appropriate. We agree that 
E10 most appropriately reflects in-use gasoline around the country 
today and into the foreseeable future, and thus we are finalizing E10 
for the test fuel. In addition, as discussed in Section IV.F.1, we are 
finalizing a fuel volatility specification for test fuel of 9 psi RVP, 
as proposed.
     We are finalizing a set of standards for PM as measured on 
the aggressive-driving segment of the SFTP test cycle (the US06 cycle) 
based on US06 PM test data that we published as part of the NPRM, along 
with more recent test data developed by California. Our review of these 
data has led us to finalize numerically lower levels for the US06 PM 
standards than we proposed. The data presented in the NPRM as well as 
the data provided by California clearly show that the proposed US06 PM 
standards were inappropriately high, that US06 PM emissions are not 
closely related to vehicle weight, and that lower values for the 
standards would achieve the goal of the program to bring all vehicles 
in the light-duty fleet to the US06 PM levels that are being met by 
many vehicles today. Based on the body of available data, we are 
establishing 6 mg/mi as the long-term US06 PM standard. (This compares 
to the proposed standards of 10 and 20 mg/mi for lighter and heavier 
light-duty vehicles, respectively.) However, because there remains some 
uncertainty about how manufacturers will achieve this level in the 
early years of the program, we are setting the standard at 10 mg/mi for 
the early years of the program, for MYs 2017 and 2018. Similarly, we 
are providing a less-stringent standard of 10 mg/mi for testing of in-
use vehicles in recognition of the challenges of the requirements as 
vehicles age.
     In the Tier 3 program, as for vehicle emission control 
programs in the past, manufacturers are responsible for the emissions 
performance of the vehicle for a specified ``useful life'' of the 
vehicle. EPA proposed that vehicles meet the Tier 3 standards for 
150,000 miles or 15 years, identical to the LEV III program's approach. 
We proposed an option for lighter light-duty vehicles to certify to a 
shorter useful life of 120,000 miles or 10 (or 11, as applicable) 
years, as set in the Tier 2 program. We proposed that manufacturers 
certifying to the shorter useful life would need to meet numerically 
lower NMOG+NOX standards (85 percent of the respective

[[Page 23451]]

150,000-mile NMOG+NOX standards). We also proposed that a 
manufacturer choosing the shorter useful life for one vehicle model 
would need to use that useful life and associated standards for all of 
its lighter vehicles. Auto industry commenters stated that applying the 
provision across a manufacturer's fleet would create an onerous 
compliance burden. We have reconsidered our proposed approach, and as 
discussed in Section IV.A.7.c below, we will allow a manufacturer to 
split its lighter light-duty fleet among models certified for either 
the 150,000 mile or 120,000 mile useful life and associated standards.
     Another area of substantial comment, primarily from the 
petroleum refining industry, questioned the technological need of auto 
manufacturers for lower in-use sulfur levels in order to meet the Tier 
3 vehicle emission standards. In contrast, auto manufacturers and 
emissions control system manufacturers commented that lower sulfur 
gasoline is critical to meet the Tier 3 standards. After careful 
consideration of the comments, we continue to believe that the large 
body of data presented in the NPRM, supplemented by newer data that 
consistently reinforces the earlier conclusions, strongly supports our 
determination of the need for average in-use gasoline sulfur levels to 
be at 10 ppm sulfur or lower for manufacturers to meet the Tier 3 
vehicle standards across their fleets for the useful life of the 
vehicles. See Section IV.A.6 below for a detailed discussion of the 
need for gasoline sulfur control.
b. Structure of the Primary Tier 3 Tailpipe Standards
    As proposed, compliance with the standards is based on vehicle 
testing using test procedures that represent a range of vehicle 
operation, including the Federal Test Procedure (FTP) and the 
Supplemental Federal Test Procedure (SFTP). The Tier 3 FTP and SFTP 
NMOG+NOX standards are fleet-average standards, meaning that 
the manufacturer calculates the sales-weighted average emissions of the 
vehicles it sells in each model year, accounting for any Tier 3 
emissions credits or deficits, and compares that average to the 
applicable standard for that model year. The fleet average standards 
for NMOG+NOX evaluated over the FTP are the same values as 
proposed and are summarized in Table IV-2 and discussed in detail 
below. For lighter light-duty vehicles, the standards begin in MY 2017 
at a level representing a 46 percent reduction from the current Tier 2 
requirements for lighter vehicles and then become increasingly 
stringent, culminating in an 81 percent reduction in MY 2025. The FTP 
NMOG+NOX program includes separate fleet average standards 
for heavier vehicles that begin in MY 2018 and then converge with the 
standards for lighter vehicles at 30 milligrams per mile (mg/mi) in MY 
2025 and later, as proposed.251 252
---------------------------------------------------------------------------

    \251\ The declining NMOG+NOX fleet-average standards 
consist of one set of declining standards that applies to light-duty 
vehicles (LDVs) and small light trucks (LDT1s) and a second set of 
declining standards that applies to heavier light trucks (LDT2s, 
LDT3s. LDT4s), and MDPVs.
    \252\ This preamble presents the new Tier 3 standards in terms 
of milligrams per mile (mg/mi) for convenience. Throughout the 
associated Tier 3 regulatory language we continue to present the 
standards in terms of grams per mile (g/mi) for consistency with 
earlier programs.
---------------------------------------------------------------------------

    Manufacturers will determine their fleet average FTP 
NMOG+NOX emission values as we proposed, based on the per-
vehicle ``bin standards'' to which they certify each vehicle model. 
Manufacturers will be free to certify vehicles to any of the bins, so 
long as the sales-weighted average of the NMOG+NOX values 
from the selected bins meets the fleet average standard for that model 
year. Table IV-1 presents the per-vehicle bin standards. Similarly, the 
fleet average NMOG+NOX standards measured over the SFTP are 
summarized in Table IV-4 and discussed in detail below. The SFTP 
NMOG+NOX fleet average standards decline from MY 2017 until 
MY 2025. In this case, the same standards apply to both lighter and 
heavier vehicles. In MY 2025, the SFTP NMOG+NOX standard 
reaches its fully phased-in fleet average level of 50 mg/mi.
    Also as proposed, the new Tier 3 PM standards apply to each vehicle 
separately. The PM standards are per-vehicle cap standards and not 
fleet-average standards. Also, in contrast to the declining 
NMOG+NOX standards, the PM standard on the FTP is a constant 
3 mg/mi for all vehicles and for all model years, phasing in to an 
increasing percentage of vehicle sales beginning in MY 2017 for 
vehicles at or below 6,000 lbs Gross Vehicle Weight Rating (GVWR) and 
in MY 2018 for vehicles above 6,000 lbs GVWR. As discussed in Section 
IV.A.3.b above, based on data generated by EPA and CARB test programs, 
most current light-duty vehicles are already performing at or below the 
3 mg/mi level. However, some vehicles are emitting above this level, 
due to such factors as excessive fueling during cold start and 
combustion chamber and fuel system designs that are not optimized for 
low PM emissions. The intent of the 3 mg/mi standard is to bring all 
light-duty vehicles to the PM level typical of that being demonstrated 
by most light-duty vehicles today. To address the uncertainties that 
will accompany the introduction of new technologies, the program 
includes a separate in-use FTP PM standard of 6 mg/mi for the testing 
of in-use vehicles during the phase-in period, as proposed, as 
described in more detail below.
    As presented in Table IV-3, for vehicles at or below 6000 lbs GVWR, 
these FTP PM certification and in-use standards phase in over several 
years, beginning with a requirement that at least 20 percent of a 
company's U.S. sales of these vehicles comply with the Tier 3 standards 
in MY 2017. We are also finalizing an option for a manufacturer to 
choose to certify 10 percent of its total light-duty fleet sales--
including LDVs and LDT over 6,000 lbs GVWR and MDPVs--to the Tier 3 FTP 
PM standards in MY 2017. Manufacturers would reach a 100 percent 
compliance requirement in MY 2021.
    Finally, the Tier 3 program includes PM standards evaluated over 
the US06 cycle (a component of the SFTP test that captures higher 
speeds and accelerations). Based on emissions test data presented in 
the NPRM and additional data submitted in public comments, and as 
presented in Table IV-5 and further discussed in Section IV.A.4.b 
below, we are establishing a single long-term US06 PM standard of 6 mg/
mi for both lighter and heavier vehicles, a level that is numerically 
lower than what we proposed. However, because there remains some 
uncertainty about how manufacturers will decide to achieve this level 
in the early years of the program, we are setting the standard through 
MY 2018 at 10 mg/mi. The US06 PM standards phase in using the same 20-
20-40-70-100 percent schedule, and on the same vehicles, as the new FTP 
PM standards. The 10 mg/mi standard applies in MYs 2017 and 2018 (at a 
percent-of-sales requirement of 20 percent, and the long-term 6 mg/mi 
standard applies in MYs 2019 and later, increasing from 40 to 100 
percent of sales. This US06 standard will apply to the same vehicle 
models that a manufacturer chooses to certify to the FTP PM standard 
during the percent phase-in period. As in the case of the FTP PM 
standards, the intent of the standard is to bring the emission 
performance of all vehicles to that already being demonstrated by many 
vehicles in the current light-duty fleet. As proposed, we include a 
separate in-use US06 PM standard during in the middle years of the 
program, but at a different numerical level and during

[[Page 23452]]

different years than proposed (as discussed in Section IV.A.4.b below).
    We did not propose new emission requirements for any vehicle or 
fuel over the cold temperature test cycles (i.e., the 20 [deg]F cold 
carbon monoxide (CO) and non-methane hydrocarbon (NMHC) tests), but 
requested comment on that decision. Only the automakers commented on 
this topic, agreeing with EPA's approach of not changing its cold 
temperature requirements. As indicated in the proposal, we are not 
establishing any new cold temperature requirements in this rule.
c. Alternate Phase-In Schedules
    For heavier light-duty vehicles (i.e., LDVs and LDTs greater than 
6,000 lbs GVWR, plus MDPVs), EPA is also finalizing alternative phase-
in schedules for each of the four primary vehicle emission standards: 
FTP NMOG+NOX, FTP PM, SFTP NMOG+NOX, and US06 
PM.\253\ These alternative phase-ins are available if a manufacturer 
prefers stable standards and four full years of lead time, as specified 
in the Clean Air Act for heavier vehicles. We describe each of the 
alternative phase-ins in more detail below, including several ways in 
which we have revised the proposed provisions.
---------------------------------------------------------------------------

    \253\ Tier 3 standards for CO and HCHO phase in with the 
NMOG+NOX standards, as applicable.
---------------------------------------------------------------------------

    EPA received comment on the proposed alternative phase-in 
provisions, primarily from automakers and their trade associations. 
These comments questioned whether the proposed structure of and 
restrictions on the use of the alternative phase-ins were so onerous as 
to unduly restrict a manufacturer from choosing the alternative phase-
ins and their lead time and stability provisions as set forth in the 
Clean Air Act. The commenters criticized the proposed requirement that 
a manufacturer using the alternative phase-ins apply the alternative 
schedules to its entire light-duty fleet, both below and above 6,000 
lbs GVWR. EPA had proposed this provision to minimize the complexity of 
complying with the alternative phase-in if a manufacturer's heavier and 
lighter light-duty vehicles had different compliance structures.
    In consideration of these concerns, we have removed from the 
alternative phase-in provisions the requirement that a manufacturer 
apply the alternative schedules to its entire light-duty fleet 
including vehicles below 6,000 lbs GVWR. For the practical functioning 
of the program, the final rule requires that any manufacturer choosing 
to use the alternative phase-in apply all four alternative phase-in 
schedules to its entire light-duty fleet above 6,000 lbs GVWR. We 
believe that the alternative phase-ins allow manufacturers to comply 
with emission standards in a time frame that is clearly feasible and 
fully compliant with the CAA requirements for lead time and regulatory 
stability. To the extent that manufacturers choose to use them, the 
alternative would result in overall emission reductions essentially 
identical to those of the primary program.
    The alternative phase-in schedules would begin to apply to each 
vehicle for either MY 2019 or MY 2020, depending on exactly when the 
manufacturer begins production of the vehicle. (See Section 86.1811-
17(b)(8)(i) for how we implement this provision.) For models that begin 
MY 2019 production after the fourth anniversary of the signing of this 
final rule, the alternative phase-in would provide four full years of 
lead time and would first apply for MY 2019. The phase-in obligation 
would be calculated based only on those vehicles beginning production 
after the fourth anniversary date. For models beginning production 
before that date, the alternative phase-in would first apply for MY 
2020, and the phase-in percentage for MY 2020 would be based on the 
manufacturer's entire fleet of heavier light-duty vehicles. Based on 
historical certification patterns, few models begin production before 
mid-calendar-year, so we expect that the vast majority of MY 2019 
vehicles will begin production after the 4-year anniversary and thus 
the alternative phase-ins, if chosen, will typically apply beginning in 
MY 2019.
    At the time of certification for MY 2018, a manufacturer must 
declare whether it intends to apply the alternative phase-in schedules 
to its heavier light-duty vehicles. A manufacturer choosing the 
alternative phase-ins would be committed to this phase-in approach for 
the duration of the phase-ins, and could not later choose the fleet-
average approach for NMOG+NOX standards. For all vehicles 
below 6,000 lbs GVWR, the primary program will apply, beginning in MY 
2017. For a manufacture's vehicles subject to the alternative phase-
ins, there would be no new tailpipe emissions requirements beyond the 
Tier 2 program until the beginning of the alternative phase-in 
schedules; that is, MY 2019 or 2020, as explained above.
    As discussed above, a manufacturer choosing the alternative phase-
in approach for its heavier light-duty vehicles would be required to 
use all four phase-ins together. The next paragraphs explain how each 
of the alternative phase-ins requires an increasing percent of the 
manufacturer's sales to comply with the alternative standards. Thus, 
until the end of the phase-ins, some percent of a manufacturer's 
affected vehicles will meet the new standard and the remainder of that 
year's sales will not yet comply with Tier 3. For the practical 
functioning of the program, a manufacturer choosing the alternative 
phase-ins would be required to comply with exactly the same segment of 
their fleet in each model year for all four alternative phase-ins. For 
example, a manufacturer that complies with the 70 percent MY 2020 
requirement for the FTP NMOG+NOX standard with a segment of 
its vehicle fleet must meet the 70 percent MY 2020 requirement for the 
FTP PM standard with the same set of vehicles. Vehicles covered by the 
alternative phase-in programs would be considered ``Final Tier 3'' 
vehicles and thus would also need to comply with the Tier 3 
certification fuel and full useful life provisions.
    For the FTP and SFTP NMOG+NOX alternative phase-in 
schedules, once the phase-in is complete for a segment of a 
manufacturer's fleet, the standards continue for that set of vehicles 
through MY 2024, after which the full Tier 3 program applies regardless 
of the phase-in strategy. Thus, the fleet-average standards that 
decline through MY 2024 do not apply for these vehicles.
    Although manufacturers would implement all four alternative phase-
in schedules together, as discussed above, each alternative phase-in 
has unique characteristics. The following paragraphs explain the unique 
provisions of each.
(1) Alternative Phase-In Schedule for the FTP NMOG+NOX 
Standard
    Instead of the primary FTP NMOG+NOX declining fleet 
average standards, a manufacturer choosing the alternative phase-ins 
would comply with a stable fleet average FTP NMOG+NOX 
standard of 30 mg/mi that would apply to an increasing percentage of a 
manufacturer's combined sales of LDVs and LDTs above 6,000 lbs GVWR and 
MDPVs. This percent phase-in would match the percentages in the primary 
PM percent phase-in schedule, as discussed above--specifically, 40 
percent of MY 2019 heavier light-duty vehicles (excluding those 
vehicles with production beginning before the 4-year anniversary), 70 
percent of all of its heavier light-duty vehicles in MY 2020, and 100 
percent compliance in MY 2021 and later model years.

[[Page 23453]]

(2) Alternative Phase-In Schedule for the FTP PM Standard
    Instead of the primary FTP PM percent phase-in schedule, a 
manufacturer choosing the alternative phase-ins would postpone the 
beginning of its FTP PM phase-in for its LDVs and LDTs above 6,000 lbs 
GVWR and MDPVs until MY 2019 or 2020 (depending on the dates production 
begins for its vehicle models, as discussed above). The manufacturer 
would then comply with the 3 mg/mi per-vehicle FTP PM standard (and the 
6 mg/mi in-use standard) on an increasing percentage of these vehicles, 
following the 40-70-100 percentage phase-in of the primary PM program--
specifically, 40 percent of MY 2019 heavier light-duty vehicles 
(excluding those vehicles with production beginning before the 4-year 
anniversary), 70 percent of all of its heavier light-duty vehicles in 
MY 2020, and 100 percent compliance in MY 2021 and later model years.
(3) Alternative Phase-In Schedule for the SFTP NMOG+NOX 
Standard
    As with the other alternative phase-ins, instead of the primary 
SFTP NMOG+NOX declining fleet average standards, a 
manufacturer choosing the alternative phase-ins would comply with a 
stable fleet average SFTP NMOG+NOX standard of 50 mg/mi that 
would apply to an increasing percentage of a manufacturer's combined 
sales of LDVs and LDTs above 6000 lbs GVWR and MDPVs. This percent 
phase-in again would match the percentages in the primary PM percent 
phase-in schedule, as discussed above--specifically, 40 percent of MY 
2019 heavier light-duty vehicles (excluding those vehicles with 
production beginning before the 4-year anniversary), 70 percent of all 
of its heavier light-duty vehicles in MY 2020, and 100 percent 
compliance in MY 2021 and later model years.
(4) Alternative Phase-In Schedule for the US06 PM Standard
    Finally, instead of the primary US06 PM percent phase-in schedule, 
a manufacturer choosing the alternative phase-ins would postpone the 
beginning of the US06 phase-in for its LDVs and LDTs above 6,000 lbs 
GVWR and MDPVs until MY 2019 or 2020 (depending on the dates production 
begins for its vehicle models, as discussed above). The manufacturer 
would then comply with the 10 mg/mi US06 PM standard for 40 percent of 
MY 2019 heavier light-duty vehicles (excluding those vehicles with 
production beginning before the 4-year anniversary), 70 percent of all 
of its heavier light-duty vehicles in MY 2020, with 100 percent 
compliance in MY 2021, and then 100 percent compliance with the 6 mg/mi 
standard in MY 2022 and later model years.
    The next sections describe in more detail the new Tier 3 standards, 
how they will be implemented over time, and the technological 
approaches that we believe are or will be available to manufacturers in 
order to comply.
3. FTP Standards
    As summarized above, we are finalizing, largely as proposed, new 
standards for the primary pollutants of concern for this rule (NMOG, 
NOX, and PM) as measured on the FTP. The following 
paragraphs describe in more detail these FTP standards for 
NMOG+NOX and PM, as well as for carbon monoxide (CO) and 
formaldehyde (HCHO).
a. FTP NMOG+NOX Standards
    The Tier 3 NMOG and NOX standards are expressed in terms 
of the sum of the two pollutants--NMOG+NOX in mg/mi.\254\ We 
received no comments recommending a different approach. The California 
LEV III standards are also expressed as NMOG+NOX; aligning 
Tier 3 with LEV III is an important element of facilitating a national 
program.
---------------------------------------------------------------------------

    \254\ See California Low-Emission Vehicles (LEV) & GHG 2012 
regulations adopted by the State of California Air Resources Board, 
March 22, 2012, Resolution 12-21 incorporating by reference 
Resolution 12-11, which was adopted January 26, 2012. Available at 
http://www.arb.ca.gov/regact/2012/leviiighg2012/leviiighg2012.htm 
(last accessed December 2, 2013).
---------------------------------------------------------------------------

    EPA received a number of comments about how the proposed 
NMOG+NOX standards transition from the existing Tier 2 
standards, but there was little comment recommending different levels 
of the standards themselves, especially later in the program. Based on 
our extensive evaluation of existing and emerging vehicle technologies 
(see Section IV.A.5) and the level of sulfur in gasoline that will be 
available during the implementation timeframe of this rule, and 
considering the comments we received, we continue to believe that the 
fully phased-in level for the fleet-average FTP NMOG+NOX 
standard of 30 mg/mi is the most stringent level that we can reasonably 
establish. As discussed in Sections IV.A.5 and IV.A.6 below, when 
necessary margins of compliance and the demonstrated effects of fuel 
sulfur on emissions performance are considered, the 30 mg/mi standard 
is effectively very close to zero. The 30 mg/mi Tier 3 
NMOG+NOX standard is also consistent with the final LEV III 
standard.
    A key compliance mechanism adapted from the Tier 2 program is a 
``bin'' structure for the FTP emission standards. For these purposes, a 
bin is a set of several standards that must be complied with as a 
group. Thus, as proposed, each FTP Tier 3 bin has an 
NMOG+NOX standard and a PM standard, as well as CO and HCHO 
standards.
    We intend for the Tier 3 CO and HCHO standards to prevent new 
engine and emission control designs that result in increases in CO and 
HCHO emissions, compared to levels being achieved today. The standards 
are based on the comparable current LEV II and Tier 2 bin standards for 
these pollutants, which we believe are sufficiently protective at this 
time. There were no comments on the proposed CO and HCHO standards. The 
current standards are not technology-forcing, and we believe that this 
will continue to be the case as Tier 3 technologies are developed.
    Table IV-1 presents the bin structure for light-duty vehicle, 
light-duty truck, and MDPV FTP standards.

                            Table IV-1--Tier 3 FTP Standards for LDVs, LDTs and MDPVs
                                                     [mg/mi]
----------------------------------------------------------------------------------------------------------------
                                                                      NMOG+NOX   PM\a\ (mg/            HCHO (mg/
                                Bin                                   (mg/mi)       mi)     CO (g/mi)     mi)
----------------------------------------------------------------------------------------------------------------
Bin 160...........................................................          160          3        4.2          4
Bin 125...........................................................          125          3        2.1          4
Bin 70............................................................           70          3        1.7          4
Bin 50............................................................           50          3        1.7          4

[[Page 23454]]

 
Bin 30............................................................           30          3        1.0          4
Bin 20............................................................           20          3        1.0          4
Bin 0.............................................................            0          0          0          0
----------------------------------------------------------------------------------------------------------------
\a\ In MYs 2017-20, the PM standard applies only to that segment of a manufacturer's vehicles covered by the
  percent of sales phase-in for that model year.

    Consistent with the Tier 2 principle of vehicle and fuel 
neutrality, the same Tier 3 standards apply to all LDVs, LDTs, or 
MDPVs, regardless of the fuel they use, as proposed. That is, vehicles 
certified to operate on any fuel (e.g., gasoline, diesel fuel, E85, 
CNG, LNG, hydrogen, and methanol) are all subject to the same 
standards.
    The Tier 3 NMOG+NOX standards as measured on the FTP 
will reduce the combined fleet-average emissions gradually from MY 2017 
through 2025, as shown in Table IV-2 below. Beginning in MY 2017, there 
are two separate sets of fleet-average standards for, first, LDVs and 
LDT1s and, second, all other LDTs (LDT2s, LDT3s, and LDT4s) and MDPVs. 
Both fleet-average standards decline annually, converging in MY 2025. 
These declining average standards are identical to CARB's LEV III 
standards.\255\
---------------------------------------------------------------------------

    \255\ See California Low-Emission Vehicles (LEV) & GHG 2012 
regulations adopted by the State of California Air Resources Board, 
March 22, 2012, Resolution 12-21 incorporating by reference 
Resolution 12-11, which was adopted January 26, 2012. Available at 
http://www.arb.ca.gov/regact/2012/leviiighg2012/leviiighg2012.htm 
(last accessed January 14, 2014).
---------------------------------------------------------------------------

    As proposed and as discussed above (Section IV.A.2.a), the 
declining fleet-average NMOG+NOX FTP standards begin in MY 
2017 for light-duty vehicles and light-duty trucks with a GVWR up to 
and including 6,000 lbs and in MY 2018 for light-duty vehicles and 
light-duty trucks with a GVWR greater than 6,000 lbs and MDPVs. The 
standards apply to the heavier vehicles a year later to facilitate the 
transition to a 50-state program for all manufacturers. During this 
transition period, as described above, there will be two fleet-average 
NMOG+NOX standards for each model year, one for LDVs and 
LDT1s and one for all other LDTs (LDT2s, LDT3s, and LDT4s) and for 
MDPVs that decline essentially linearly from MY 2017 through MY 2025. 
At that point, the two fleet-average standards converge and stabilize 
for all later model years at the same level, 30 mg/mi, as shown in 
Table IV-2.

                   Table IV-2--Tier 3 LDV, LDT, and MDPV Fleet Average FTP NMOG+NOX Standards
                                                     [mg/mi]
----------------------------------------------------------------------------------------------------------------
                                                                        Model year
                                         -----------------------------------------------------------------------
                                                                                                           2025
                                           2017    2018    2019    2020    2021    2022    2023    2024     and
                                            \a\                                                            later
----------------------------------------------------------------------------------------------------------------
LDV/LDT1 \b\............................      86      79      72      65      58      51      44      37      30
LDT2,3,4 and MDPV.......................     101      92      83      74      65      56      47      38  ......
----------------------------------------------------------------------------------------------------------------
\a\ For LDVs and LDTs over 6,000 lbs GVWR and MDPVs, the fleet average standards apply beginning in MY 2018.
\b\ These standards apply for a 150,000 mile useful life. Manufacturers can choose to certify their LDVs and
  LDV1s to a useful life of 120,000 miles. If a vehicle model is certified to the shorter useful life, a
  proportionally lower numerical fleet average standard applies, calculated by multiplying the respective
  150,000 mile standard by 0.85 and rounding to the nearest mg/mi. See Section IV.A.7.c.

    As discussed above (Section IV.A.2.c), for LDVs and LDTs above 
6,000 lbs GVWR and MDPVs, EPA is also providing an alternative phase-in 
of the fleet-average 30 mg/mi FTP NMOG+NOX standard.
b. FTP PM Standards
    We are establishing new FTP standards for PM emissions at the 
proposed levels--3 mg/mi, with a temporary standard of 6 mg/mi for in-
use vehicle testing--as summarized in Table IV-3 below. These levels 
are intended to ensure that all new vehicles will perform at a level 
representing what is already being achieved by well-designed emission 
control technologies today.
    Many commenters were either silent on or supportive of the proposed 
FTP PM standard levels. However, some commenters--including CARB and 
several NGOs and auto industry suppliers--supported a more stringent 
standard of 1 mg/mi, which the California LEV III program phases in 
beginning in MY 2025. After detailed consideration of these comments 
and information available at this time, we continue to believe that the 
PM standards that we are finalizing for the federal Tier 3 program are 
the most stringent technically feasible standards within the 
implementation timeframe of this rule. (See Section 1.5.1 of the RIA.) 
We will continue to work closely with CARB in this area. Specifically, 
our agencies will continue our parallel evaluations of how improved 
gravimetric PM measurement methods can reduce PM mass measurement 
variability at very low PM levels and how this relates to the evolving 
technological capabilities of automakers to reach very low PM levels 
with sufficient compliance margins.
    PM emissions over the FTP are generally attributed to the cold 
start, when PM formation from combustion of the fuel is facilitated by 
the operating conditions, including a cold combustion chamber and fuel 
enrichment. During cold-start operation, PM control is less effective, 
especially the oxidation by the catalytic converter of semi-volatile 
organic compounds from the lubricating oil. We believe that for 
vehicles that are not already at the Tier 3 levels, the new

[[Page 23455]]

standards can be achieved with improvements to the fuel controls during 
the cold start, without the need for any new technology or hardware. We 
also expect that manufacturers will pay close attention to maintaining 
low PM emissions during the implementation of newer technologies like 
gasoline direct injection (GDI) and turbocharged engines. Improvements 
in cold-start exhaust catalyst performance for NMOG+NOX 
control will also reduce emissions of semi-volatile organic PM. For 
these reasons, cold start PM levels are relatively independent of 
vehicle application and therefore we are finalizing a single FTP PM 
standard for all light-duty vehicles, as proposed.
    Unlike the NMOG+NOX FTP standard, it is not necessary 
for the FTP PM standard to phase in on a declining curve over time, 
since most manufacturers are already producing vehicles that meet the 
new standards. We are finalizing the proposed PM FTP percent-of-sales 
phase-in during the first 5 years of the Tier 3 program in response to 
concerns expressed by automakers about logistical, facilities, and 
compliance challenges with a standard in the range of 3 mg/mi in the 
early years of the program. Beginning in MY 2017 (and in MY 2018 for 
LDVs and LDTs over 6,000 lbs GVWR and MDPVs), manufacturers will need 
to comply with the PM standard with a minimum of 20 percent of their 
U.S. sales. As shown in Table IV-3, the percentage of the 
manufacturer's sales that need to comply increases each year, reaching 
100 percent in MY 2021. In addition to this percent phase-in, we are 
also establishing, as proposed, a separate PM standard of 6 mg/mi that 
will apply only for in-use testing of vehicles certified to the new 
standards, and only during the percent phase-in period.
    Due to the MY 2018 start date for vehicles over 6,000 lbs GVWR, 
manufacturers that have few or no vehicle models over 6,000 lbs GVWR 
will be required to certify a larger percentage of their total light-
duty sales in MY 2017 than full line manufacturers. While we believe 
that most manufacturers will likely choose a single large-volume 
durability group to meet the 2017 requirements, we are also including 
an option that a manufacturer could use to comply with the MY 2017 PM 
requirements. Under this option, a manufacturer may choose to certify 
10 percent of its total light-duty vehicle sales in MY 2017 to the new 
PM standards, including light-duty vehicles over 6,000 lbs. This 
approach is consistent with the CARB LEV III program, which requires 
that 10 percent of all light-duty vehicle sales meet the new PM 
standards in MY 2017.
    Because of the expected time and expense of performing emission 
tests on the improved PM test procedures, we are limiting the number of 
tests using the new procedures that a manufacturer needs to perform at 
certification and during in-use testing, as proposed. Specifically, 
manufacturers will only be required to test vehicles representing a 
minimum of 25 percent of a model's durability test groups during 
certification each model year (and a minimum of 2 durability 
groups).\256\ Manufacturers may select which durability groups to test, 
but will need to rotate the groups tested each year to eventually cover 
their whole fleet. Similarly, manufacturers performing in-use testing 
under the In-Use Verification Program can limit their testing to 50 
percent of their low- and high-mileage test vehicles. Again, 
manufacturers will need to rotate their vehicle models so that each 
model will be tested every other year. Overall, we believe that the 
flexibility that these provisions provide will facilitate the 
expeditious implementation of the Tier 3 program, with no significant 
impact on the benefits of the program.
---------------------------------------------------------------------------

    \256\ Durability groups are a subset of engine families. Several 
engine families may have the same durability group.

                         Table IV-3--Summary of Tier 3 LDV, LDT, and MDPV FTP Standards
----------------------------------------------------------------------------------------------------------------
                                                                   Model year
                                            --------------------------------------------------------
        Program element            Units      2017                                                      Notes
                                               \a\    2018    2019    2020    2021    2022    2023+
----------------------------------------------------------------------------------------------------------------
NMOG+NOX Standard (fleet        mg/mi......           Per declining fleet averages (see Table IV-2) \b\
 average).
----------------------------------------------------------------------------------------------------------------
PM Standards
----------------------------------------------------------------------------------------------------------------
Phase-in......................  %..........   20\c\      20      40      70     100     100     100  ...........
----------------------------------------------------------------------------------------------------------------
FTP:
    Certification.............  mg/mi......       3       3       3       3       3       3       3  Note d.
    In-use....................  mg/mi......       6       6       6       6       6       3       3  Note e.
----------------------------------------------------------------------------------------------------------------
\a\ For LDVs and LDTs above 6,000 lbs GVWR and MDPVs, the FTP PM standards apply beginning in MY 2018.
\b\ The percent phase-in does not apply to the declining fleet average standards.
\c\ Manufacturers comply in MY 2017 with 20 percent of their LDV and LDT fleet under 6,000 lbs GVWR, or
  alternatively with 10 percent of their total LDV, LDT, and MDPV fleet.
\d\ Manufacturers must test 25 percent of each model year's durability groups, and a minimum of 2.
\e\ Manufacturers must test 50 percent of their combined low- and high- mileage in-use vehicles.

    As discussed in Section IV.A.2.c above, for LDVs and LDTs above 
6,000 lbs GVWR and MDPVs, EPA is providing an alternative phase-in of 
the 3 mg/mi FTP PM standard.
4. SFTP Standards
    In addition to addressing vehicle emissions during typical driving, 
as addressed by the FTP standards presented above, the Tier 3 program 
also addresses emissions during more severe driving conditions. Thus, 
we are finalizing NMOG+NOX and PM standards as measured on 
the SFTP. The SFTP (and specifically the US06 component of the test) is 
designed to simulate, among other conditions, higher speeds and higher 
acceleration rates, and thus higher loads. As described below, most 
commenters were supportive of or silent on the proposed SFTP 
NMOG+NOX standards and the associated declining fleet-
average phase-in schedule, but several commenters stated that the level 
of the standards should be more stringent than proposed. Based on our 
analysis of the stringency

[[Page 23456]]

of the program, discussed in Section IV.A.5 below and in Chapter 1 of 
the RIA, we disagree that more stringent SFTP NMOG+NOX 
standards are necessary or appropriate at this time, and we are 
finalizing the standards and phase-in schedule as proposed. However, we 
are finalizing more stringent SFTP standards for PM, which focus on the 
US06 test component, based on newer data and public comments. These are 
also described below.
    The Tier 3 SFTP standards are necessary to address emissions during 
high-load conditions, when engines can go into a fuel ``enrichment'' 
mode and the engine's controls may temporarily create a rich air/fuel 
mixture to protect exhaust components from thermal damage. Enrichment 
can increase emissions of NMOG+NOX and PM, primarily due to 
the incomplete combustion that occurs under rich conditions and the 
diminished effectiveness of the catalyst in these circumstances. 
However, enrichment can be minimized or eliminated in current and 
future engines, where components can be thermally protected even under 
high-load conditions by careful electronic management of the air/fuel 
mixture and the combustion process. We are finalizing these SFTP 
standards, as well as limitations on the amount of enrichment that 
drivers can command (see Section IV.A.4.c below) to address this 
important source of vehicle emission.
    We are also finalizing an SFTP composite CO standard of 4.2 g/mi 
for all model years 2017 (or 2018 for LDVs and LDTs over 6000 lbs GVWR 
and MDPVs) and later. This standard represents no effective change from 
the current Tier 2 SFTP CO standard, which we believe is already at a 
level that is sufficiently stringent.
a. SFTP NMOG+NOX Standards
    We are finalizing the Tier 3 SFTP NMOG+NOX standards and 
declining fleet-average phase-in schedule as proposed and as presented 
in Table IV-5 below. Most commenters were generally supportive of these 
standards or silent about them. However, several commenters stated that 
the proposed standards are too lenient, based on their evaluation of 
vehicle emission test data we presented in the NPRM. We have considered 
these comments and have reviewed the data from the NPRM. Our conclusion 
from that data continues to be that the SFTP NMOG+NOX 
emission levels that we are finalizing ensure that manufacturers 
essentially eliminate fuel enrichment events and their emissions 
consequences, thereby resulting in important emissions reductions. See 
Chapter 1 of the RIA for an analysis of this data. We do not believe 
that significant additional reductions would result from SFTP weighted 
NMOG+NOX standards more stringent than the 50 mg/mi fully 
phased-in level. In addition, we believe that the 50 mg/mi standard 
will ensure that the SFTP performance of future vehicles with future 
technologies continues to be comparable to that of the current fleet. 
The SFTP emissions value for certification of gaseous pollutants will 
continue to be calculated as a weighted composite value of emissions on 
three cycles (0.35 x FTP + 0.28 x US06 + 0.37 x SC03), as is done for 
the Tier 2 SFTP standards.
    To provide flexibility in meeting the fleet-average standards, 
manufacturers will, as proposed, determine the specific SFTP composite 
standard for each individual vehicle family and report that self-
selected standard and the measured emission performance. (These self-
selected standards are analogous to ``family emission limits,'' or 
``FELs,'' used in other programs (e.g., heavy-duty highway engine 
standards).) For each family, a manufacturer will choose any composite 
NMOG+NOX standard, up to 180 mg/mi, in even 10 mg/mi 
increments. The manufacturer will then calculate the sales-weighted 
average of all the selected standards of the families across its fleet 
and compare that emissions value to the applicable fleet-average 
standards for that model year. Table IV-4 presents the declining fleet-
average SFTP NMOG+NOX standards.
    As discussed in Section IV.A.2.c above, for LDVs and LDTs above 
6,000 lbs GVWR and MDPVs, EPA is providing an alternative phase-in of 
the 50 mg/mi SFTP NMOG+NOX standard.
b. US06 PM Standards
    We are finalizing a single short-term US06 PM standard of 10 mg/mi 
for MYs 2017 and 2018 (or only for MY 2018 for LDVs and LDTs over 6,000 
lbs GVWR and MDPVs) and a single long-term standard of 6 mg/mi for MY 
2019 and later. These standards are numerically lower than those we 
proposed, and less complex in their structure. As discussed below and 
in Chapter 1 of the RIA, a substantial body of more recent PM data from 
a variety of vehicles tested on the US06 cycle has given us greater 
understanding of the feasible level of control of these emissions, both 
currently and in the timeframe of the Tier 3 standards, including what 
level of control we may reasonably require for the light-duty fleet. 
The standards we are finalizing reflect this review. Much of the more 
recent data was developed late in the development of the NPRM and, 
although we made it available in the rulemaking docket to inform 
potential commenters, the proposed standards did not reflect 
consideration of the newer data. Since the NPRM, additional data from 
CARB have become available, and we have considered all of this 
information in finalizing the US06 PM standards.
    We believe that the fully phased-in US06 PM standard of 6 mg/mi 
will achieve the goal that we presented in the NPRM--to maintain the 
performance being achieved by current well-performing vehicles taking 
into account reasonable compliance margins. Comments from stakeholders 
representing states, including CARB, and several NGOs urged EPA to 
finalize more stringent standards than those proposed, in some cases 
advocating for standards below 6 mg/mi. Conversely, auto industry 
commenters generally supported the proposed standards. We have 
concluded that the body of recent data clearly shows that the long-term 
6 mg/mi standard, is the appropriate level to prevent any significant 
``backsliding'' in US06 PM emissions as new vehicles and technologies 
enter the fleet. At the same time, the 6 mg/mi standard provides a 
reasonable compliance margin--about 50% above the average levels of 
current vehicles, which are averaging about 4 mg/mi. A long-term 
standard numerically lower than 6 mg/mi would run counter to our intent 
to bring the emissions performance of all vehicles to that already 
being demonstrated by many vehicles in the current light-duty fleet. We 
believe the long-term US06 PM standard we are finalizing is appropriate 
based on all of the information available at this time and will not 
hinder introduction of new technologies manufacturers may choose for 
compliance with the other Tier 3 standards or other rules.

[[Page 23457]]

    The short-term, less-stringent US06 standard of 10 mg/mi 
(applicable in MYs 2017 and 2018) responds to automaker concerns about 
uncertainties stemming from simultaneous regulatory requirements and 
rapidly evolving exhaust and engine technologies in the coming years. 
We recognize that vehicle control technologies for both criteria and 
GHG emissions are evolving and will continue to do so, including an 
expected expansion of gasoline direct injection (GDI) technologies (see 
IV.A.5.c and the RIA). Also, the transition to lower sulfur in-use 
gasoline required by this rule may create temporary additional 
challenges in consistently achieving lower US06 PM emissions (see 
IV.A.6 and the RIA). We believe that most manufacturers will implement 
similar if not identical emission control strategies to comply (or, 
more often, to continue to comply with) with both the 10 mg/mi and the 
6 mg/mi standards. In so doing, we expect them to use the temporary 
additional compliance margin provided by the 10 mg/mi standard to 
reduce uncertainties about potential variability in performance (in use 
and, in particular, later in vehicle life) during the early years of 
developing and commercializing their control technologies.\257\
---------------------------------------------------------------------------

    \257\ We note that the purpose of the percent phase-in schedule 
for the FTP and US06 PM standards is to facilitate the expansion of 
manufacturers' PM testing facilities, which have been relatively 
limited in their availability prior to these new emission standards. 
While effectively providing more time for technology development as 
well as for expansion of facilities, we believe that the PM 
standards are designed to be fully feasible in the early years of 
the program and do not themselves require the phase-in relief, 
especially given the short-term 10 mg/mi standard and the temporary 
relaxed in-use testing standards.
---------------------------------------------------------------------------

    The 10 mg/mi standard will expire after MY 2018, and the long-term 
standard of 6 mg/mi will take effect. As the implementation of the 
program continues, we believe a limited degree of relief for testing of 
in-use vehicles is appropriate. Manufacturers commented that because of 
the industry's general lack of experience with stringent PM standards, 
especially as the newly-designed vehicles age, less stringent standards 
for in-use testing would reduce near-term concerns about performance 
variability early in the program. We agree, and we are finalizing a 
separate standard of 10 mg/mi for in-use vehicle testing for the 
intermediate years of the program, MYs 2019 through MY 2023. This 
standard is numerically lower than the proposed in-use standards--again 
because of the availability of improved US06 test data as described 
above--but the purpose of providing an in-use standard remains the 
same. The in-use standard, in conjunction with the short-term 10 mg/mi 
standard represents a longer duration for the in-use standard than we 
had proposed, again based on comments from the industry about their 
compliance concerns with new US06 standards. For MY 2024 and later, 
there will be no separate in-use standard and all vehicles will need to 
meet the long-term standard at certification and in use.
    EPA proposed that different US06 PM standards apply to lighter and 
heavier vehicles. The newer US06 PM test data discussed above also make 
clear that the US06 PM performance of current vehicles is not closely 
related to vehicle weight, although the earlier data had indicated that 
this might be the case. Several commenters urged EPA to finalize a 
single standard for vehicles above and below 6,000 lbs GVWR based on 
the newer data. At the same time, auto manufacturers generally 
supported the proposed vehicle weight distinction, asserting a higher 
degree of uncertainty about the emission performance of their larger 
vehicles, especially in the early years of the program and in light of 
simultaneous technology challenges. The newer data clearly show that 
larger vehicles today are generally achieving US06 PM levels very 
similar to smaller vehicles, and well below the proposed standards. We 
are not finalizing separate US06 standards for heavier and lighter 
vehicles because separate standards are unwarranted based on a review 
of the newer data. However, we believe that the short-term 10 mg/mi 
standard, as well as the temporary in-use vehicle testing standard, 
will significantly reduce manufacturer compliance uncertainties in the 
early years of the program for all vehicles, as discussed above.
    As with the FTP PM standards, manufacturers will comply with the 
US06 PM standards with the same increasing minimum percentage of their 
vehicles, as shown in Table IV.5. Also as with the FTP PM phase-in, we 
are providing the option for a manufacturer to choose to certify 10 
percent of its total light-duty vehicle sales in MY 2017 to the new 
US06 PM standards, including light-duty vehicles over 6,000 lbs GVWR.
    As discussed in Section IV.A.2.c above, for LDVs and LDTs more than 
6,000 lbs GVWR and MDPVs, EPA is also providing an alternative phase-in 
of the US06 PM standards.
    All of the SFTP/US06 standards are shown in Table IV-4 and Table 
IV-5.

                                      Table IV-4--Tier 3 LDV, LDT, and MDPV SFTP Composite Fleet Average Standards
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                            Model year
                                         ---------------------------------------------------------------------------------------------------------------
                                           2017 \a\     2018       2019       2020       2021       2022       2023       2024        2025 and later
--------------------------------------------------------------------------------------------------------------------------------------------------------
NMOG+NOX (mg/mi)........................        103         97         90         83         77         70         63         57  50
--------------------------------------------------------------------------------------------------------------------------------------------------------
CO (g/mi)...............................                                                      4.2 \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ For LDVs and LDTs above 6,000 lbs GVWR and MDPVs, the NMOG+NOX and CO standards apply beginning in MY 2018.


                                             Table IV-5--Summary of LDV, LDT, and MDPV Tier 3 SFTP Standards
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                Model year
                                                            ------------------------------------------------------------------------
            Program element                    Units           2017                                                                         Notes
                                                               \a\      2018     2019     2020     2021     2022     2023    2024+
--------------------------------------------------------------------------------------------------------------------------------------------------------
NMOG+NOX Standard (fleet average).....  mg/mi..............                  Per declining fleet average for cars and trucks (see Table IV-4) \b\
--------------------------------------------------------------------------------------------------------------------------------------------------------
PM Standards:
    Phase-in..........................  %..................   20 \c\       20       40       70      100      100      100      100  ...................

[[Page 23458]]

 
US06:
    LDV, LDT, MDPV: Certification.....  mg/mi..............       10       10        6        6        6        6        6        6  Note d.
    LDV, LDT, MDPV: In-Use............                                              10       10       10       10       10
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ For LDVs and LDTs above 6,000 lbs GVWR and MDPVs, the standards apply beginning in MY 2018.
\b\ The percent phase-in does not apply to the declining fleet average standards.
\c\ Manufacturers comply in MY 2017 with 20 percent of their LDV and LDT fleet under 6,000 lbs GVWR, or alternatively with 10 percent of their total
  LDV, LDT, and MDPV fleet.
\d\ Manufacturers must test 25 percent of each model year's durability groups, minimum of 2.

c. Enrichment Limitation for Spark-Ignition Engines
    To prevent emissions that result from excessive enrichment from 
auxiliary emission control devices (AECD) that are substantially 
present during the SFTP cycles, we are finalizing limitations on the 
magnitude of enrichment that can be commanded, including enrichment 
episodes encountered during in-use operation. During conditions where 
enrichment is demonstrated to be present on the SFTP, the nominal air-
to-fuel ratio cannot be richer at any time than the leanest air-to-fuel 
ratio required to obtain maximum torque (lean best torque or LBT). An 
air-to-fuel ratio of LBT plus a tolerance of 4 percent additional 
enrichment will be allowed in actual vehicle testing to protect for any 
in-use variance in the air-to-fuel ratio from the nominal LBT air-to-
fuel determination, for such reasons as air or fuel distribution 
differences from production variances or aging.
    LBT is defined as the leanest air-to-fuel ratio required at a speed 
and load point with a fixed spark advance to make peak torque. 
Specifically, an increase in fuel will not result in an increase in 
torque while maintaining a fixed spark advance. LBT is determined by 
setting the spark advance to a setting that is less than or equal to 
the spark advance required for best torque (MBT) and maintaining that 
spark advance when sweeping the air-to-fuel ratio. This fixed spark 
advance requirement is intended to prevent torque changes related to 
spark changes masking true LBT. One manufacturer commented that there 
is no universally accepted definition or procedure to determine LBT so 
we should retain the Tier 2 LBT requirements. We believe that the 
proposed definition provides sufficient clarity and will generally 
agree with most manufacturers' internal definition of LBT. 
Additionally, we are finalizing the flexibility that manufacturers may 
request approval of an alternative LBT definition for a unique 
technology or control strategy. The Agency may determine that an 
enrichment amount is excessive or not necessary and therefore deem that 
the approach does not meet the air-to-fuel ratio requirements.
    Enrichment required for thermal protection will continue to be 
allowed upon demonstration of necessity to the Agency, based upon 
temperature limitations of the engine or exhaust components. 
Manufacturers will be required to provide descriptions of all 
components requiring thermal protection, temperature limitations of the 
components, how the enrichment strategy will detect over-temperature 
conditions and correct them, and a justification regarding why the 
enrichment is the minimum necessary to protect the specific components. 
The Agency may determine that the enrichment is not justified or is not 
the minimum necessary based on the use of engineering judgment using 
industry-reported thermal protection requirements.
    A manufacturer commented that this requirement to report enrichment 
requirements for component protection for every application is 
burdensome and unnecessary. EPA believes that closer review of off-
cycle enrichment by the agency, including enrichment for component 
protection, is necessary to ensure emissions are well controlled under 
all operating conditions. While this requirement may in some cases 
require additional resources at certification, this information has 
generally been required to be maintained by manufactures to support use 
of enrichment as an auxiliary emission control device (AECD) and 
therefore should be an exercise of reporting existing records for most 
manufacturers.
    The requirements described in this section apply for vehicles 
certified to any of the Tier 3 standards.
5. Feasibility of the NMOG+NOX and PM Standards
    In the proposal, we concluded that all of the Tier 3 emissions 
standards are technologically feasible in the time frame of the 
program. The technical conclusions we reached at that time have been 
further reinforced by information we received in the public comments or 
has otherwise become available and placed in the docket for this 
rulemaking. After considering the comments received and with additional 
supporting information in Chapter 1 of the RIA, we conclude that the 
Tier 3 standards are feasible and reasonable, considering lead-time 
provided and expected compliance costs.
    For each of the emission standards, the lead time provided by the 
program is more than sufficient for all manufacturers to comply. First, 
manufacturers in many cases are already adopting complying technologies 
for reasons other than this rulemaking. For example, many of the 
technologies that manufacturers have begun to develop for model years 
as early as MY 2014 in response to the CARB LEV III FTP and SFTP 
NMOG+NOX standards for the California market will likely 
represent steps toward compliance with this national program. 
Similarly, manufacturers have been producing some limited vehicle 
offerings since as early as MY 2000 that comply with our final MY 2025 
standards in response to the CARB PZEV requirements. In addition, as 
described above, our program incorporates a number of phase-in 
provisions that will ease the transition to compliance, including time 
some manufacturers may need to install PM testing capability and to 
ramp up production on a national scale. This feasibility assessment is 
based on a variety of complementary technical data, studies, and 
analyses. As described below, these include our analysis of the 
stringency of the standards as compared to current Tier 2 emission 
levels. We also discuss below our observation that manufacturers are 
currently certifying several vehicle models under the California LEV II 
program that could likely achieve the Tier 3 NMOG+NOX and PM 
standards or similar levels. EPA has assessed the

[[Page 23459]]

emissions control challenges manufacturers will generally face (e.g., 
cold start NMOG reductions and running (warmed-up) NOX 
emissions under typical and more aggressive driving conditions) and the 
corresponding technologies that we expect to be available to 
manufacturers to meet these challenges. Our feasibility assessment 
accounts for the fact that the Tier 3 program will apply to all types 
of new vehicles, ranging from small cars to large pick-up trucks and 
MDPVs and representing a wide diversity in applications and in specific 
engine designs.
    It is important to note that our primary assessment of the 
feasibility of engine and emission control technologies is based on the 
assumption that vehicles will be certified on gasoline with a fuel 
sulfur content of 10 ppm and operated on in-use gasoline with an 
average of 10 ppm sulfur.\258\ Therefore, our primary assessment does 
not incorporate the degradation of emission control system caused by 
higher levels of sulfur content, as is discussed in Section IV.A.6 
below and further discussed in the RIA. This assessment reinforces the 
critical role of gasoline sulfur control in making it possible for EPA 
to establish emission standards at these very stringent levels. See 
Section IV.6 below for a full discussion of our current knowledge of 
the effects of gasoline sulfur on current Tier 2 vehicle emissions as 
well as our projections of how we expect that sulfur will affect 
compliance on vehicles with standards in the range of the Tier 3 
standards. The projections are based on extensive EPA testing of Tier 2 
vehicles as well as targeted evaluation of passenger cars and heavier 
trucks performing at or near the Tier 3 Bin 30 (30 mg/mi 
NMOG+NOX) including manufacturer supplied data of a 
prototype Tier 3 light-duty truck as discussed in Section IV.6.
---------------------------------------------------------------------------

    \258\ Our technology, feasibility, and cost assessments are also 
consistent with an assumption that certification fuel will contain 
10 percent ethanol and will have other properties as specified in 
Section IV.F below.
---------------------------------------------------------------------------

    Since there are multiple aspects to the Tier 3 program, it is 
necessary to consider technical feasibility in light of the different 
program requirements and their interactions with each other. In many 
cases, manufacturers will be able to address more than one requirement 
with the same general technological approach (e.g., faster catalyst 
light-off can improve both FTP NMOG+NOX and PM emissions). 
At the same time, the feasibility assessment must consider that 
different technologies may be needed on different types of vehicle 
applications (e.g., cars versus trucks) and must consider the relative 
effectiveness of these technologies in reducing emissions for the full 
useful life of the vehicle while operating on expected in-use fuel. For 
example, certain smaller vehicles with correspondingly small engines 
may be less challenged to meet FTP standards than larger vehicles with 
larger engines. Conversely, these smaller vehicles may have more 
difficulty meeting the more aggressive SFTP requirements than vehicles 
with larger and more powerful engines. Additionally, the ability to 
meet the SFTP emission requirements can also be impacted by the path 
taken to meet the FTP requirements (e.g., larger volume catalysts for 
US06 emissions control vs. smaller catalysts for improved FTP cold-
start emissions control). Throughout the following discussion, we 
address how these factors, individually and in interaction with each 
other, affect the feasibility of the final program.
a. FTP NMOG+NOX Standards
    The Tier 3 emission requirements include stringent 
NMOG+NOX standards on the FTP that will require new vehicle 
hardware in order to achieve the 30 mg/mi fleet average level in MY 
2025. The type of new hardware that will be required will vary 
depending on the specific application and emission challenges. Smaller 
vehicles with corresponding smaller engines will generally need less 
new hardware while larger vehicles may need additional hardware and 
improvements beyond what will be needed for the smaller vehicles. While 
some vehicles, especially larger light trucks, may face higher costs in 
meeting the standards, it is important to remember that not every 
vehicle needs to meet the standard. The program has been structured to 
provide higher emission standard ``bins'' (see Table IV-1 above) to 
which manufacturers may certify more challenged vehicles, so long as 
these vehicles are offset with vehicles certified in lower emission 
bins such that the fleet-wide average meets the standards. We believe 
that the availability of the less-stringent bins will allow for the 
balancing of feasibility and cost considerations of compliance 
strategies for all vehicles. In the Tier 2 program, manufacturers took 
advantage of this flexibility, especially in the early years of the 
program. Then, as technologies improved and/or became less expensive 
and the need for averaging diminished, manufacturers began certifying 
all or most of their fleets to the average bin (Tier 2 Bin 5). We 
anticipate that manufacturers will follow a similar trend with the Tier 
3 standards, relying on fleet averaging more significantly in the 
transitional years but certifying increasing numbers of their vehicles 
to the final fleet average standard of 30 mg/mi in the later years of 
the program.
    In order to assess the technical feasibility of a 30 mg/mi 
NMOG+NOX national fleet average FTP standard, EPA conducted 
two supporting analyses. The initial analyses performed were of the 
current Tier 2 and LEV II fleets. This provided a baseline for the 
current federal fleet emissions performance, as well as the emissions 
performance of the California LEV II fleet. The second consideration 
was a modal analysis of typical vehicle emissions under certain 
operating conditions. In this way EPA determined the specific emissions 
performance challenges that vehicle manufacturers will face in meeting 
the lower fleet average emission standards. Each of these 
considerations is described in greater detail below.
    The current Tier 2 federal fleet is certified to an average of Tier 
2 Bin 5, equivalent to 160 mg/mi NMOG+NOX.\259\ As an 
example, for MY 2009 when the Tier 2 program was fully implemented 
across all vehicle types, 92 percent of LDVs and LDT1s were certified 
to Tier 2 Bin 5 and 91 percent of LDT2s through LDT4s were certified to 
Tier 2 Bin 5. This trend has generally continued through MY 2013 as the 
most recent certification results indicate that manufacturers are 
continuing to certify primarily to Tier 2 Bin 5 standards for the 
federal fleet however there has been a shift to more certifications 
using the cleaner bins as discussed in the RIA. This is not an 
unexpected result as there is no motivation prior to implementation of 
the Tier 3 rulemaking for vehicle manufacturers to produce a federal 
fleet that over-complies with respect to the existing Tier 2 standards. 
By comparison, in the California fleet where compliance with the 
declining fleet average NMOG requirement and the ``PZEV'' program 
requires manufacturers to certify vehicles to cleaner levels, only 30 
percent of the LDVs and LDT1s are certified to Tier 2 Bin 5 and 60 
percent are certified to cleaner bins such as Tier 2 Bin 3 and 4. The 
situation regarding the truck fleet in California is similarly 
stratified, with 37 percent of the LDT2s through LDT4s being certified 
to Tier 2

[[Page 23460]]

Bin 5 and 55 percent being certified to the cleaner Tier 2 Bin 3 and 4. 
In many cases identical vehicles are being certified to a lower 
standard in California and a higher standard federally simply because 
there is no incentive to over perform to the federal standards. We note 
that vehicles certified to a lower standard in California are operated 
on gasoline with an average sulfur content of 10 ppm and thereby are 
able to maintain their emissions performance in-use. Based on these 
patterns of federal and California certification, EPA believes that 
much of the existing Tier 2 fleet could currently be certified to a 
lower federal fleet average immediately, with no significant 
feasibility concerns, if lower sulfur gasoline were made available 
nationwide.
---------------------------------------------------------------------------

    \259\ The Tier 2 program does not combine NMOG and 
NOX emissions into one fleet-average standard. The fleet-
average standard in that program is for NOX emissions 
alone. The NOX fleet-average requirement of .07 gm/mi is 
the same level as the Bin 5 NOX standard.
---------------------------------------------------------------------------

    Regardless of the Tier 2 bin standards at which manufacturers 
choose to certify their vehicles, actual measured emissions performance 
of these vehicles is typically well below the numerical standards. This 
difference is referred to as ``compliance margin'' and is a result of 
manufacturers' efforts to address all the sources of variability, 
including:

 Test-to-test variability (within one test site and lab-to-lab)
 Build variation expectations
 Manufacturing tolerances and stack-up
 Vehicle operation (for example: driving habits, ambient 
temperature, etc.)
 Fuel composition
 The effects of fuel sulfur on exhaust catalysts and oxygen 
sensors
 The effects of other fuel components, including ethanol and 
gasoline additives
 Oil consumption
 The impact of oil additives and oil ash on exhaust catalysts 
and oxygen sensors

    For MY 2009 thru MY 2013, the compliance margin for a Tier 2 Bin 5 
vehicle averaged approximately 60 percent. In other words, actual 
vehicle emissions performance was on average about 40 percent of a 160 
mg/mi NMOG+NOX standard, or about 64 mg/mi. By comparison, 
for California-certified vehicles, the average Super Ultra Low Emission 
Vehicle (SULEV) compliance margin was somewhat less for the more 
stringent standards, approximately 50 percent. We believe that the 
recent California experience is a likely indicator of compliance 
margins that manufacturers will design for in order to comply with the 
Tier 3 FTP standards. Thus, a typical Tier 2 Bin 5 vehicle, performing 
at 40 percent of the current standard (i.e., at about 64 mg/mi) will 
need improvements sufficient to reach about 15 mg/mi (50 percent of a 
30 mg/mi standard).
    To understand how the several currently-used technologies described 
below could be used by manufacturers to reach the stringent Tier 3-
NMOG+NOX standards, it is helpful to consider emissions 
formation in common modes of operation for gasoline engines, or modal 
analysis.\260\ The primary challenge faced by manufacturers for 
producing Tier 3 compliant light-duty gasoline vehicle powertrains will 
be keeping warmed-up running emissions at effectively zero emissions 
levels while reducing the emissions during cold-start operation which, 
based on modal analysis of a gasoline-powered vehicle being operated on 
the FTP cycle, occurs during about the first 50 seconds after engine 
start. Thus, we believe that to comply with the Tier 3 FTP standards, 
manufacturers will focus on effective control of these cold-start 
emissions while maintaining zero running emissions; this is only 
possible when sulfur levels in the fuel do not degrade catalyst 
performance. As discussed below, light-duty manufacturers are already 
applying several technologies capable of significant reductions in 
these cold start emissions to vehicles currently on the road.
---------------------------------------------------------------------------

    \260\ A modal analysis provides a second-by-second view of the 
total amount of emissions over the entire cycle being considered.
---------------------------------------------------------------------------

    During the analysis of current vehicles certified to the cleanest 
emission levels (Tier 2 Bin 2 and LEV II SULEV) it was noted that no 
large pick-ups equipped with their application specific engines were 
performing at the 30 mg/mi NMOG+NOX level. We believe that 
these applications may be the most challenging due to the fact that the 
design criteria required to provide the utility aspect may have direct 
impact on their ability to implement some of the technologies described 
in section IV.A.5.d below. Since these vehicles represent a substantial 
and important part of the light- duty fleet, EPA performed a technical 
feasibility study directly targeting this class of vehicles.
    In order to assess the technical feasibility of a 30 mg/mi FTP 
NMOG+NOX standard, EPA purchased a 2011 Chevrolet Silverado 
heavy-light-duty (LDT4) pickup truck with a developmental goal of 
modifying the truck to achieve exhaust emission levels in compliance 
with the Tier 3 Bin 30 emissions standards including a reasonable 
compliance margin. The truck was equipped with a 5.3L V8 with General 
Motors' ``Active Fuel Management'' cylinder deactivation system. This 
particular truck was chosen as an example of a Tier 3 prototype in part 
because cylinder deactivation is a key technology for light-truck 
compliance with future GHG standards and in part because it achieved 
very low emissions in the OEM, Tier 2-compliant configuration 
(certified to Tier 2 Bin 4). A prototype exhaust system was obtained 
from MECA consisting of high-cell-density (900 cpsi) thin-wall (2.5 
mil), high-PGM, close-coupled Pd-Rh catalysts with an additional under-
body Pd-Rh catalyst. The total catalyst volume was approximately 116 
in\3\ with a specific PGM loading of 125 g/ft\3\ and approximate 
loading ratio of 0:80:5 (Pt:Pd:Rh). Third-party (non-OEM) EMS 
calibration tools were used to modify the powertrain calibration in an 
effort to improve catalyst light-off performance. The final test 
configuration used approximately 4 degrees of timing retard and 
approximately 200 rpm higher idle speed relative to the OEM 
configuration during and immediately following cold-start. The exhaust 
catalyst system and HEGO sensors were bench aged to an equivalent 
150,000 miles using standard EPA accelerated catalyst bench-aging 
procedures. The truck was tested on California LEV III E10 
certification fuel at 9 ppm gasoline sulfur levels.
    The EPA Tier 3 prototype Silverado achieved NMOG+NOX 
emissions of 18 mg/mi on the 9 ppm S fuel. The NMOG+NOX 
emissions were approximately 60% of the Bin 30 standard and thus are 
consistent with meeting the Tier 3 Bin 30 exhaust emissions standard 
with a moderate compliance margin. The technologies used on the 
prototype Silverado to achieve these emission levels are common 
approaches used today on smaller vehicles. They do not compromise any 
of the design utility of this vehicle class and are some of the same 
approaches we expect manufacturers to use to meet the Tier 3 Bin 30 
exhaust emissions standards.
b. SFTP NMOG+NOX Standards
    The increase in the stringency of the SFTP NMOG+NOX 
standards, specifically across the US06 cycle, will generally only 
require additional focus on fuel control of the engines and diligent 
implementation of new technologies that manufacturers are already 
introducing or are likely to introduce in response to the current and 
2017 LD GHG emission standards. These include downsized gasoline direct 
injection (GDI) and turbocharged engines, which may also include

[[Page 23461]]

improvements to the engine and emission control hardware to tolerate 
higher combustion and exhaust temperatures expected in these future 
GHG-oriented engine designs when under higher loads. The upgraded 
materials or components will enable manufacturers to rely less on fuel 
enrichment during high-speed/high-load operation to protect components 
from overheating. This fuel enrichment is currently the source of 
elevated VOC, NOX, and PM emissions seen in a subset of the 
current Tier 2 fleet.
    With respect to enrichment, the primary method available to 
manufacturers to protect the catalyst and other exhaust components from 
over-temperature conditions has been changes to the fuel/air mixture by 
increasing the fuel fraction, but this is no longer the only tool 
available to manufacturers for this purpose. With the application of 
electronic throttle controls, variable valve timing, exhaust gas 
recirculation and other exhaust temperature influencing technologies on 
nearly every light-duty vehicle, the manufacturer has the ability to 
systematically control the operation and combustion processes of the 
engine to minimize or altogether avoid areas and modes of operation 
where thermal issues can occur. While some of these solutions could in 
some cases result in a small and temporary reduction in vehicle 
performance (absolute power levels), we believe that it could be an 
effective way to reduce NMOG+NOX emissions over the SFTP 
test.
    Additionally, some components, especially catalysts, can experience 
accelerated thermal deterioration that occurs when operating at higher 
temperatures for more time than expected under normal operation (e.g., 
trailer towing, mountain grades). Some upgrades of existing vehicle 
emission control technology, like catalyst substrates and washcoats may 
be required to limit thermal deterioration and ensure vehicle emissions 
compliance throughout the useful life of the vehicle.
    In order to assess the technical feasibility of a 50 mg/mi 
NMOG+NOX national fleet average SFTP standard, EPA conducted 
an analysis of SFTP levels of Tier 2 and LEV II vehicles. The analysis 
was performed on the US06 results from current Tier 2 and LEV II 
vehicles tested in the in-use verification program (IUVP) by 
manufacturers and submitted to EPA. This analysis provided a baseline 
for the current Tier 2 and LEV II fleet emissions performance, as well 
as the SFTP emissions performance capability of the cleanest vehicles 
meeting the Tier 3 FTP standards. The analysis concluded that most 
vehicles in the IUVP testing program are already capable of meeting the 
composite SFTP standard of 50 mg/mi when the Tier 3 FTP standard levels 
are factored into the composite calculation. With the technological 
improvements already underway as discussed above, we believe all MY 
2017 and later vehicles will be able to comply with the SFTP standards, 
either directly or through the flexibility of the averaging, banking 
and trading program. For further information on the analysis see 
Chapter 1 of the RIA.
c. FTP and SFTP PM Standards
    As described above for NMOG+NOX over the SFTP, the 
increase in the stringency of the FTP and SFTP PM standards will 
generally also only require additional focus on fuel control of the 
engines and attention to PM emissions during the implementation of new 
technologies like gasoline direct injection (GDI) and turbocharged 
engines. Some upgrades of existing vehicle emission control technology 
may be required to ensure vehicle emissions performance is maintained 
throughout the useful life of the vehicle. These upgrades may include 
improvements to the engine to control wear that could result in 
increased PM from oil consumption and selection of GDI systems that 
will be capable of continuing to perform optimally even as the systems 
age.
    We based our conclusions about the ability of manufacturers to meet 
the PM standards largely on the PM performance of the existing fleet, 
both on the FTP and SFTP. In the case of FTP testing of current 
vehicles, data on both low and high mileage light-duty vehicles 
demonstrate that the majority of vehicles are currently achieving 
levels at or below the Tier 3 FTP PM standards.
    The testing results can be found in Chapter 1 of the RIA. A small 
number of vehicles are at or just over the Tier 3 FTP PM standard at 
low mileage and could require calibration changes and/or catalyst 
changes to meet the new standards. It is our expectation that the same 
calibration and catalyst changes required to address NMOG will also 
provide the necessary PM control. Vehicles that currently have higher 
PM emissions over the FTP or SFTP at higher mileages will likely be 
required to control oil consumption and combustion chamber deposits.
    We also analyzed PM test data results on the US06 test cycle from 
Tier 2 vehicles. The data show that many vehicles are already at or 
below the Tier 3 standards on the US06 test cycle. Vehicles that have 
high PM emission rates on the US06 will likely need to control 
enrichment and oil consumption, particularly later in life. As 
described above for SFTP NMOG+NOX control, enrichment can be 
more accurately managed through available electronic engine controls. 
The strategies for reducing oil consumption are similar to those 
described above for controlling oil consumption on the FTP. However, 
given the higher engine speeds experienced on the US06 and the increase 
in oil consumption that can accompany this kind of operation, 
manufacturers will most likely focus on oil sources stemming from the 
piston to cylinder interface and positive crankcase ventilation (PCV).
    Manufacturers have informed us that they have already reduced or 
are planning to reduce the oil consumption of their engines by improved 
sealing of the paths of oil into the combustion chamber and improved 
piston-to-cylinder interfaces. Auto manufacturers have stated that they 
are already taking or considering these actions to address issues of 
customer satisfaction and cost of ownership. In addition, many vehicle 
manufacturers acknowledge the relationship between combustion chamber 
deposits and PM formation and are actively pursuing design changes to 
mitigate fuel impingement within the combustion chamber and its 
commensurate PM effects. Both types of controls are being widely 
applied by manufacturers today.
d. Technologies Manufacturers Are Likely To Apply
    Most of the technologies expected to be applied to light-duty 
vehicles to meet the stringent Tier 3 standards will address the 
emissions control system's ability to reduce emission during cold start 
while maintaining zero or near zero running emissions. The 
effectiveness of current vehicle emissions control systems at reducing 
cold start emissions depends in large part on the time it takes for the 
catalyst to light off, which is typically defined as the catalyst 
reaching a temperature of 250 [deg]C. In order to improve catalyst 
light-off, we expect that manufacturers will add technologies that 
provide heat from combustion more readily to the catalyst or improve 
the catalyst efficiency at lower temperatures. These technologies 
include calibration changes, catalyst platinum group metals (PGM) 
loading and strategy, thermal management, close-coupled catalysts, and 
secondary air injection, all which generally improve emission 
performance of all pollutants. In some cases where the catalyst light-
off and efficiency are not

[[Page 23462]]

enough to address the cold start NMOG emissions, hydrocarbon adsorbers 
may be applied to trap hydrocarbons until such time that the catalyst 
is lit off. Note that with the exception of hydrocarbon adsorbers each 
of these technologies addresses NMOG, NOX, and PM 
performance. The technologies are described in greater detail below. 
Additional information on these technologies can also be found in 
Chapter 1 of the RIA.
     Engine Control Calibration Changes--These include changes 
to retard spark and/or adjust air/fuel mixtures such that more 
combustion heat is created during the cold start. Control changes may 
include injection strategies in GDI applications, unique cold-start 
variable valve timing and lift, and other available engine parameters. 
Engine calibration changes can affect NMOG, NOX and PM 
emissions.
     Catalyst PGM Loading--Additional PGM loading, increased 
loading of other active materials, and improved dispersion of PGM and 
other active materials in the catalyst provide a greater number of 
sites available to catalyze emissions and addresses NMOG, 
NOX and PM emissions. Catalyst PGM loading, when implemented 
in conjunction with low sulfur gasoline, will effectively eliminate 
NOX emissions under warmed-up conditions.
     Thermal Management--This category of technologies includes 
all design attributes meant to conduct the combustion heat into the 
catalyst with minimal cooling. This includes insulating the exhaust 
piping between the engine and the catalyst, reducing the wetted area of 
the exhaust path, reducing the thermal mass of the exhaust system, and/
or using close-coupled catalysts (i.e., the catalysts are packaged as 
close as possible to the engine's cylinder head to mitigate the cooling 
effects of longer exhaust piping). Thermal management technologies 
primarily address NMOG emissions, but also affect NOX and PM 
emissions.
     Secondary Air Injection--By injecting air directly into 
the exhaust stream, close to the exhaust valve, combustion can be 
maintained within the exhaust, creating additional heat by which to 
increase the catalyst temperature. The air/fuel mixture must be 
adjusted to provide a richer exhaust gas for the secondary air to be 
effective. There can be a NOX emissions disbenefit to use of 
secondary air injection since it can impact the ability of oxygen 
storage components (OSC) within the catalyst to take up excess oxygen 
as necessary to promote NOX reduction reactions immediately 
following cold start conditions.
     Hydrocarbon Adsorber--Traps hydrocarbons during a cold 
start until the catalyst lights off, and then releases the hydrocarbons 
to be converted by the catalyst.
     Gasoline Sulfur--The relative effectiveness for NMOG and 
NOX control of the exhaust-catalyst related technologies is 
constrained by gasoline fuel sulfur levels. Thus, reduced sulfur in 
gasoline is an enabling technology to achieve the standards and 
maintain this performance during in-use operation. We discuss the 
relationship between gasoline sulfur and emissions in greater detail in 
Section IV.6 below and in the RIA.
    Several commenters indicated that large light-duty trucks (e.g., 
pickups and full-size sport utility vehicles (SUVs) in the LDT3 and 
LDT4 categories) will be the most challenging light-duty vehicles to 
bring into compliance with the Tier 3 NMOG+NOX standards at 
the 30 mg/mi corporate average emissions level. A similar challenge was 
addressed when large light-duty trucks were brought into compliance 
with the Tier 2 standards over the past decade. Figure IV-1 provides a 
graphical representation of the effectiveness of Tier 3 technologies 
for large light-duty truck applications. A compliance margin is shown 
in both cases. Note that the graphical representation of the 
effectiveness of catalyst technologies on NOX and NMOG when 
going from Tier 2 to Tier 3 levels also includes a reduction in 
gasoline sulfur levels from 30 ppm to 10 ppm.
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    \261\ The technologies and levels of control in this figure are 
based on a combination of confidential business information 
submitted by auto manufacturers and suppliers, public data, and EPA 
staff engineering judgment.

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[[Page 23463]]

[GRAPHIC] [TIFF OMITTED] TR28AP14.000

6. Impact of Gasoline Sulfur Control on the Effectiveness of the 
Vehicle Emission Standards
    In this section, we discuss the impact of gasoline sulfur control 
on the feasibility of the Tier 3 vehicle emissions standards and on the 
exhaust emissions of the existing in-use vehicle fleet. Section 
IV.A.6.a describes the chemistry and physics of the impacts of gasoline 
sulfur compounds on exhaust catalysts. Sections IV.A.6.b, c and d 
summarize research on the impacts of gasoline sulfur on vehicles 
utilizing various degrees of emission control technology, with Section 
IV.A.6.b summarizing historical studies on the impact of gasoline 
sulfur on vehicle emissions, Section IV.A.6.c describing impacts on 
Tier 2 vehicles and the existing light-duty vehicle fleet, and Section 
IV.A.6.d describing impacts on vehicles using technology consistent 
with what we expect to see in the future Tier 3 vehicle fleet. Section 
IV.A.6.e provides EPA's assessment of the level of gasoline sulfur 
control necessary for light-duty vehicles to comply with Tier 3 exhaust 
emission standards.
    EPA's primary findings are:
     Reducing gasoline sulfur content to a 10 ppm average will 
provide immediate and significant exhaust emissions reductions to the 
current, in-use fleet of light-duty vehicles.
     Reducing gasoline sulfur content to an average of 10 ppm 
will enable vehicle manufacturers to certify their entire product lines 
of new light-duty vehicles to the final Tier 3 Bin 30 fleet average 
standards. Without such sulfur control it would not be possible for 
vehicle manufacturers to reduce emissions sufficiently below Tier 2 
levels to meet the new Tier 3 standards because it would require 
offsetting significantly higher exhaust emissions resulting from the 
higher sulfur levels. EPA has not identified any existing or developing 
technologies that would compensate for or offset the higher exhaust 
emissions resulting from higher fuel sulfur levels.
a. Gasoline Sulfur Impacts on Exhaust Catalysts
    Modern three-way catalytic exhaust systems utilize platinum group 
metals (PGM), metal oxides and other active materials to selectively 
oxidize organic compounds and carbon monoxide in the exhaust gases. 
These systems simultaneously reduce NOX when air-to-fuel 
ratio control operates in a condition of relatively low amplitude/high 
frequency oscillation about the stoichiometric point. Sulfur is a well-
known catalyst poison. There is a large body of work demonstrating 
sulfur inhibition of the emissions control performance of PGM three-way 
exhaust catalyst 
systems.262 263 264 265 266 267 268 269 270 271

[[Page 23464]]

The nature of sulfur interactions with washcoat materials, active 
catalytic materials and catalyst substrates is complex and varies with 
catalyst composition, exhaust gas composition and exhaust temperature. 
The variation of these interactions with exhaust gas composition and 
temperature means that the operational history of a vehicle is an 
important factor; continuous light-load operation, throttle tip-in 
events and enrichment under high-load conditions can all impact sulfur 
interactions with the catalyst.
---------------------------------------------------------------------------

    \262\ Beck, D.D., Sommers, J.W., DiMaggio, C.L. (1994). Impact 
of sulfur on model palladium-only catalysts under simulated three-
way operation. Applied Catalysis B: Environmental 3, 205-227.
    \263\ Beck, D.D., Sommers, J.W. (1995). Impact of sulfur on the 
performance of vehicle aged palladium monoliths.'' Applied Catalysis 
B: Environmental 6, 185-200.
    \264\ Beck, D.D., Sommers, J.W., DiMaggio, C.I. (1997). Axial 
characterization of oxygen storage capacity in close coupled 
lightoff and underfloor catalytic converters and impact of sulfur. 
Applied Catalysis B: Environmental 11, 273-290.
    \265\ Waqif, M., Bazin, P., Saur, O. Lavalley, J.C., Blanchard, 
G., Touret, O. (1997), Study of ceria sulfation. Applied Catalysis 
B: Environmental 11, 193-205.
    \266\ Bazin, P., Saur, O. Lavalley, J.C., Blanchard, G., 
Visciglio, V., Touret, O. (1997). ``Influence of platinum on ceria 
sulfation.'' Applied Catalysis B: Environmental 13, 265-274.
    \267\ Takei, Y., Kungasa, Y., Okada, M., Tanaka, T. Fujimoto, Y. 
(2000). Fuel Property Requirement for Advanced Technology Engines. 
SAE Technical Paper 2000-01-2019.
    \268\ Takei, Y., Kungasa, Y., Okada, M., Tanaka, T. Fujimoto, Y. 
(2001). ``Fuel properties for advanced engines.'' Automotive 
Engineering International 109 12, 117-120.
    \269\ Kubsh, J.E., Anthony, J.W. (2007). The Potential for 
Achieving Low Hydrocarbon and NOX Exhaust Emissions from 
Large Light-Duty Gasoline Vehicles. SAE Technical Paper 2007-01-
1261.
    \270\ Shen, Y., Shuai, S., Wang, J. Xiao, J. (2008). Effects of 
Gasoline Fuel Properties on Engine Performance. SAE Technical Paper 
2008-01-0628.
    \271\ Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel 
Sulfur on FTP NOX Emissions from a PZEV 4 Cylinder 
Application. SAE Technical Paper 2011-01-0300.
---------------------------------------------------------------------------

    Sulfur from gasoline is oxidized during spark-ignition engine 
combustion primarily to SO2 and, to a much lesser extent, 
SO3-\2\. Sulfur oxides selectively chemically 
bind (chemisorb) with, and in some cases react with, active sites and 
coating materials within the catalyst, thus inhibiting the intended 
catalytic reactions. Sulfur oxides inhibit pollutant catalysis chiefly 
by selective poisoning of active PGM, ceria sites, and the alumina 
washcoating material (see Figure IV-2).\272\ The amount of sulfur 
retained by an exhaust catalyst system is primarily a function of the 
concentration of sulfur oxides in the incoming exhaust gases, air-to-
fuel ratio feedback and control by the engine management system, the 
operating temperature of the catalyst and the active materials and 
coatings used within the catalyst.
---------------------------------------------------------------------------

    \272\ Heck, R.M., Farrauto, R.J. (2002). Chapter 5: Catalyst 
Deactivation in Catalytic Air Pollution Control, 2nd Edition. John 
Wiley and Sons, Inc.
---------------------------------------------------------------------------

    In their supplemental comments to the Tier 3 proposal, API 
criticized the use of emissions data generated using gasoline with 
sulfur content outside of the range of 10 ppm to 30 ppm within EPA and 
other analyses of the impacts of gasoline sulfur on exhaust emissions 
from current in-use (Tier 2) and future (Tier 3) light-duty vehicles. 
Specific examples include:

 Comparisons of exhaust emissions at 5 ppm and 28 ppm gasoline 
sulfur levels within the recent EPA study of emissions from Tier 2 
vehicles \273\
---------------------------------------------------------------------------

    \273\ The Effects of Ultra-Low Sulfur Gasoline on Emissions from 
Tier 2 Vehicles in the In-Use Fleet, EPA-420-R-14-002.
---------------------------------------------------------------------------

 Comparison of exhaust emissions of a SULEV vehicle at 8 ppm 
and 33 ppm gasoline sulfur levels within the Takei et al. study \274\
---------------------------------------------------------------------------

    \274\ Takei, Y., Kungasa, Y., Okada, M., Tanaka, T. Fujimoto, Y. 
(2000). Fuel Property Requirement for Advanced Technology Engines. 
SAE Technical Paper 2000-01-2019.
---------------------------------------------------------------------------

 Comparison of exhaust emissions of a PZEV vehicle at 3 ppm and 
33 ppm gasoline sulfur levels within the Ball et al. study.\275\
---------------------------------------------------------------------------

    \275\ Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel 
Sulfur on FTP NOX Emissions from a PZEV 4 Cylinder 
Application. SAE Technical Paper 2011-01-0300.

    The relationship between changes in gasoline sulfur content and 
NOX, HC, NMHC and NMOG emissions is typically linear. The 
linearity of sulfur impacts on NOX, NMHC and NMOG emissions 
is supported by past studies with multiple fuel sulfur levels all of 
which compare gasoline with differing sulfur levels that are below 
approximately 100 ppm (e.g., CRC E-60 and 2001 AAM/AIAM programs as 
well as comments on this rulemaking submitted by 
MECA).276 277 278 An assumption of linearity of the effect 
of gasoline sulfur level on catalyst efficiency between any two test 
fuels with differing sulfur levels is reasonable given that the mass 
flow rate of sulfur in exhaust gas changes in proportion to its 
concentration in the fuel, and that the chemistry of adsorption of 
sulfur on the active catalyst sites is an approximately-first-order 
chemisorption until all active sites within a catalyst reach an 
equilibrium state relative to further input of sulfur compounds. The 
relative linearity of the effect of gasoline sulfur level on NMOG and 
NOX emissions allows exhaust emissions results generated 
within EPA and other studies of gasoline sulfur at levels immediately 
above or below either 10 ppm or 30 ppm to be normalized to either 10 
ppm sulfur (Tier 3 gasoline) or to 30 ppm sulfur (Tier 2 gasoline, 
which are used in the analysis of the impacts of the Tier 3 gasoline 
standards on existing in-use vehicles and future Tier 3 vehicles.
---------------------------------------------------------------------------

    \276\ Coordinating Research Council. 2003. ``The Effect of Fuel 
Sulfur on NH3 and Other Emissions from 2000-2001 Model 
Year Vehicles.'' CRC Project No. E-60 Final Report. Accessed on the 
Internet on 12/4/2013 at the following URL: http://www.crcao.com/reports/recentstudies2003/E-60%20Final%20Report.pdf.
    \277\ Alliance of Automobile Manufacturers. 2001. ``AAM-AIAM 
Industry Low Sulfur Test Program.''
    \278\ Manufacturers of Emission Controls Association. 2013. 
``The Impact of Gasoline Fuel Sulfur on Catalytic Emission Control 
Systems.''
---------------------------------------------------------------------------

    In their supplemental comments to the Tier 3 proposal, API also 
commented that EPA did not show the sulfur impact on exhaust emissions 
at intermediate sulfur levels between 10 ppm and 30 ppm. In response, 
based on the relative linearity of the effect of gasoline sulfur level 
on NMOG and NOX emissions allowing exhaust emissions to be 
estimated for gasoline sulfur levels between 10 and 30 ppm, data in 
EPA's analysis shows increases NMOG+NOX emissions (as fuel 
sulfur increases) that become more severe (i.e., higher percentage 
increase in NMOG+NOX emissions) for vehicles with extremely 
low \279\ exhaust emission (SULEV, PZEV, LEV III, Tier 3) as described 
in further detail in Sections IV.A.6.d and e.
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    \279\ Vehicles that meet the cleanest emission standards by 
demonstrate very low cold start NMOG and NOX emissions 
and zero or near-zero running NMOG and NOX emissions.

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[[Page 23465]]

[GRAPHIC] [TIFF OMITTED] TR28AP14.001

     
---------------------------------------------------------------------------

    \280\ Heck, R.M., Farrauto, R.J. (2002). Chapter 5: Catalyst 
Deactivation in Catalytic Air Pollution Control, 2nd Edition. John 
Wiley and Sons, Inc.
---------------------------------------------------------------------------

Selective sulfur poisoning of platinum (Pt) and rhodium (Rh) is 
primarily from surface-layer chemisorption. Sulfur poisoning of 
palladium (Pd) and ceria appears to be via chemisorption combined with 
formation of more stable metallic sulfur compounds, e.g. PdS and 
Ce2O2S, present in both surface and bulk form 
(i.e., below the surface layer).281 282 283 284 Ceria, 
zirconia and other oxygen storage components (OSC) play an important 
role that is crucial to NOX reduction over Rh as the engine 
air-to-fuel ratio oscillates about the stoichiometric closed-loop 
control point. \285\ Ceria sulfation interferes with OSC functionality 
within the catalyst and thus can have a detrimental impact on the 
catalyst's ability to effectively reduce NOX emissions. 
Water-gas-shift reactions are important for NOX reduction 
over catalysts combining Pd and ceria. This reaction can be blocked by 
sulfur poisoning and may be responsible for observations of reduced 
NOX activity over Pd/ceria catalysts even with exposure to 
fairly low levels of sulfur (equivalent to 15 ppm in 
gasoline).286 287 Pd is also of increased importance for 
meeting Tier 3 standards due to its unique application in the close-
coupled-catalyst location required for vehicles certifying to very 
stringent emission standards. Close-coupling means that the exhaust 
catalyst is moved as close as possible to the engine's exhaust ports 
within the packaging constraints of an engine compartment. This ensures 
that the catalyst reaches its minimal operational, or ``light-off'', 
temperature as quickly as possible after the vehicle is started. It 
also means, however, that the exhaust catalyst(s) in the close-coupled 
location(s) are subject to higher exhaust temperatures during fully-
warmed up operation. Pd is required in closed-coupled catalysts due to 
its resistance to high-temperature thermal sintering thereby 
maintaining sufficient durability of the emissions control system over 
the useful life of a vehicle. Sulfur removal from Pd requires rich 
operation at higher temperatures than required for sulfur removal from 
other PGM catalysts.
---------------------------------------------------------------------------

    \281\ Luo, T., Gorte, R.J. (2003). A Mechanistic Study of Sulfur 
Poisoning of the Water-Gas-Shift Reaction Over Pd/Ceria.'' Catalysis 
Letters, 85, Issues 3-4, pg. 139-146.
    \282\ Li-Dun, A., Quan, D.Y. (1990). ``Mechanism of sulfur 
poisoning of supported Pd(Pt)/Al2O3 catalysts 
for H2-O2 reaction.'' Applied Catalysis 61, 
Issue 1, pg. 219-234.
    \283\ Waqif, M., Bazin, P., Saur, O., Lavalley, J.C., Blanchard, 
G., Touret, O. ``Study of ceria sulfation.'' Applied Catalysis B: 
Environmental 11 (1997) 193-205.
    \284\ Bazin, P., Saur, O., Lavalley, J.C., Blanchard, G., 
Visciglio, V., Touret, O. ``Influence of platinum on ceria 
sulfation.'' Applied Catalysis B: Environmental 13 (1997) 265-274.
    \285\ Heck, R.M., Farrauto, R.J. (2002). Chapter 6: Automotive 
Catalyst in Catalytic Air Pollution Control, 2nd Edition. John Wiley 
and Sons, Inc.
    \286\ Luo, T., Gorte, R.J. (2003) A Mechanistic Study of Sulfur 
Poisoning of the Water-Gas-Shift Reaction Over Pd/Ceria. Catalysis 
Letters, 85, Issues 3-4, pg. 139-146.
    \287\ Beck, D.D., Sommers, J.W. (1995) Impact of sulfur on the 
performance of vehicle aged palladium monoliths. Applied Catalysis 
B: Environmental 6, 185-200.
---------------------------------------------------------------------------

    In addition to its interaction with catalyst materials, sulfur can 
also react with the wash-coating itself to form alumina sulfate, which 
in turn can block coating pores and reduce gaseous diffusion to active 
materials below the coating surface (see Figure IV-2).\288\ This may be 
a significant mechanism for the observed storage of sulfur compounds at 
light and moderate load operation with subsequent, rapid release as 
sulfate particulate matter emissions

[[Page 23466]]

when high-load, high-temperature conditions are encountered.\289\
---------------------------------------------------------------------------

    \288\ Beck, D.D., Sommers, J.W. (1995) Impact of sulfur on the 
performance of vehicle aged palladium monoliths. Applied Catalysis 
B: Environmental 6, 185-200.
    \289\ Maricq, M. M., Chace, R.E., Xu, N., Podsiadlik, D.H. 
(2002). The Effects of the Catalytic Converter and Fuel Sulfur Level 
on Motor Vehicle Particulate Matter Emissions: Gasoline Vehicles.'' 
Environmental Science and Technology, 36, No. 2 pg. 276-282.
---------------------------------------------------------------------------

    Operating the catalyst at a sufficiently high temperature under net 
reducing conditions (e.g., air-to-fuel equivalence that is net fuel-
rich of stoichiometry) can effectively release the sulfur oxides from 
catalyst components. Thus, regular operation at sufficiently high 
temperatures at net fuel-rich air-to-fuel ratios can minimize the 
effects of fuel sulfur levels on catalyst active materials and catalyst 
efficiency; however, it cannot completely eliminate the effects of 
sulfur poisoning. In current vehicles, desulfurization conditions occur 
typically at high loads when there is a degree of commanded enrichment 
(i.e., fuel enrichment commanded by the engine management system 
primarily for protection of engine and/or exhaust system components). A 
study of Tier 2 vehicles in the in-use fleet recently completed by 
EPA\290\ shows that emission levels immediately following high speed/
load operation is still a function of fuel sulfur level for the 
gasoline used following desulfurization. If a vehicle operates on 
gasoline with less than 10 ppm sulfur, exhaust emissions stabilize over 
repeat FTP tests at emissions near those of the first FTP that follows 
the high speed/load operation and catalyst desulfurization. If the 
vehicle continues to operate on higher sulfur gasoline following 
desulfurization, exhaust emissions creep upward until a new equilibrium 
exhaust emissions level is established. This suggests that lower fuel 
sulfur levels achieve emission benefits unachievable by catalyst 
desulfurization procedures alone. Continued operation on gasoline with 
a 10 ppm average sulfur content or lower is necessary after catalyst 
desulfurization in order to achieve emissions reductions with the 
current in-use fleet.\291\ Furthermore, regular operation at the high 
exhaust temperatures and rich air-to-fuel ratios necessary for catalyst 
desulfurization is not desirable and may not be possible for future 
Tier 3 vehicles for several reasons:
---------------------------------------------------------------------------

    \290\ The Effects of Ultra-Low Sulfur Gasoline on Emissions from 
Tier 2 Vehicles in the In-Use Fleet, EPA-420-R-14-002.
    \291\ See Preamble Section IV.A.6.c and Chapter 1 of the RIA 
(Section 1.2.3.2) for more details on this study and its results.
---------------------------------------------------------------------------

     Thermal sintering and resultant catalyst degradation: The 
temperatures necessary to release sulfur oxides are high enough to lead 
to thermal degradation of the catalyst over time via thermal sintering 
of active materials. Sintering reduces the surface area available to 
participate in reactions and thus reduces the overall effectiveness of 
the catalyst.
     Operational conditions: It is not always possible to 
maintain fuel-rich operational conditions and exhaust catalyst 
temperatures that are high enough for sulfur removal because of cold 
weather, idle conditions and light-load operation.
     Increased emissions: In order to achieve greater emission 
reductions across a fuller range of in-use driving conditions, vehicle 
manufacturers' use of commanded enrichment, which has been beneficial 
for sulfur removal, will be greatly reduced or eliminated under Tier 3. 
Additionally, the fuel-rich air-to-fuel ratios necessary for sulfur 
removal from active catalytic surfaces would result in increased PM, 
NMOG, CO and air toxic emissions, particularly at the high-temperature, 
high load conditions (e.g., US06 or comparable) necessary for sulfur 
removal. Previously used levels of commanded enrichment (e.g., under 
Tier 2) would interfere with the strategies necessary to comply with 
more stringent Tier 3 SFTP exhaust emissions standards. There are also 
additional provisions within the Tier 3 standards that further restrict 
the use of US06 and off-cycle commanded enrichment in an effort to 
reduce high-load and off-cycle PM, NMOG, CO and air toxic 
emissions.\292\
---------------------------------------------------------------------------

    \292\ See Sec.  86.1811-17 (LD) within the Tier 3 regulations. 
Tier 3 restrictions to commanded enrichment are also discussed in 
further detail within section IV.A.4.c of this preamble.
---------------------------------------------------------------------------

     Expected changes to engine performance necessary to reduce 
fuel consumption and greenhouse gas emissions will improve the thermal 
efficiency of engines and may result in reduced exhaust temperatures.
b. Previous Studies of Gasoline Sulfur Impacts
    This section summarizes studies to provide historical context 
regarding what is known about the direct impacts of gasoline sulfur on 
vehicle exhaust emissions. Reducing fuel sulfur levels has been the 
primary regulatory mechanism EPA has used to minimize sulfur 
contamination of exhaust catalysts and to ensure optimum emissions 
performance over the useful life of a vehicle. The impact of gasoline 
sulfur on exhaust catalyst systems has become even more important as 
vehicle emission standards have become more stringent. Studies have 
suggested a progressive increase in catalyst sensitivity to sulfur when 
standards increase in stringency and emissions levels decrease. 
Emission standards under the programs that preceded the Tier 2 program 
(Tier 0, Tier 1, and National LEV, or NLEV) were high enough that the 
impact of sulfur was considered of little importance. The Tier 2 
program recognized the importance of sulfur and reduced the sulfur 
levels in the fuel from around 300 ppm to 30 ppm in conjunction with 
the new emission standards.\293\ At that time, very little work had 
been done to evaluate the effect of further reductions in fuel sulfur, 
especially on in-use vehicles that may have some degree of catalyst 
deterioration due to real-world operation or on vehicles with extremely 
low tailpipe emissions as described earlier.
---------------------------------------------------------------------------

    \293\ Tier 2 Regulatory Impact Analysis, EPA 420-R-99-023, 
December 22, 1999, last accessed on the Internet on 12/04/2013 at 
the following URL: http://epa.gov/tier2.
---------------------------------------------------------------------------

    In 2005, EPA and several automakers jointly conducted a research 
program, the Mobile Source Air Toxics (MSAT) Study that examined the 
effects of sulfur and other gasoline properties such as benzene and 
volatility on emissions from a fleet of nine Tier 2 compliant 
vehicles.\294\ The study found significant reductions in 
NOX, CO and total hydrocarbons (HC) when the vehicles were 
tested on low sulfur fuel, relative to 32 ppm fuel. In particular, the 
study found a 48 percent increase in NOX over the FTP when 
gasoline sulfur was increased from 6 ppm to 32 ppm. Given the 
preparatory procedures related to catalyst clean-out and loading used 
by these studies, these results may represent a ``best case'' scenario 
relative to what would be expected under more typical driving 
conditions. Nonetheless, these data suggested the effect of in-use 
sulfur loading was largely reversible for Tier 2 vehicles, and that 
there were likely to be significant emission reductions possible with 
further reductions in gasoline sulfur level. More recently, EPA 
completed a comprehensive study on the effects of gasoline sulfur on 
the exhaust emissions of Tier 2 vehicles at low to moderate mileage 
levels.\295\ Further details of this study are summarized in Section 
IV.A.6.c of this preamble.
---------------------------------------------------------------------------

    \294\ Chapter 6 of the Regulatory Impact Analysis for the 
Control of Hazardous Air Pollutants from Mobile Sources Final Rule, 
EPA 420-R-07-002, February 2007, last accessed on the Internet on 
12/04/2013 at the following URL: http://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P1004LNN.PDF.
    \295\ The Effects of Ultra-Low Sulfur Gasoline on Emissions from 
Tier 2 Vehicles in the In-Use Fleet, EPA-420-R-14-002.
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    In the NPRM, we summarized the limited data available regarding the

[[Page 23467]]

impact of gasoline sulfur on the near-zero exhaust emission vehicle 
technologies that will be necessary for Tier 3 compliance. Vehicles 
certified to California LEV II SULEV and PZEV standards and federal 
Tier 2 Bin 2 standards achieve levels of exhaust emissions control 
consistent with the levels of control that will be necessary for Tier 3 
compliance. While these vehicles represent only a relatively small 
subset (e.g., typically small light-duty vehicles and light-duty trucks 
with limited GVWR or towing utility) of the broad range of vehicles 
that will need to comply with Tier 3 standards as part of a fleet-wide 
average, data on these vehicles provide an opportunity to study the 
impact of gasoline sulfur on near-zero exhaust emission technologies 
and is generally representative of technology that are expected to be 
used with mid-size and smaller light-duty vehicles for Tier 3 
compliance. Vehicle testing by Toyota (Takei et al.) of LEV I, LEV II 
ULEV and prototype SULEV vehicles showed larger percentage increases in 
NOX and HC emissions for SULEV vehicles as gasoline sulfur 
increased from 8 ppm to 30 ppm, as compared to other LEV vehicles they 
tested.\296\ Ball et al. of Umicore Autocat USA, Inc. studied the 
impact of gasoline fuel sulfur levels of 3 ppm and 33 ppm on the 
emissions of a 2009 Chevrolet Malibu PZEV.\297\ Umicore's testing of 
the Malibu PZEV vehicle showed a pronounced and progressive trend of 
increasing NOX emissions (referred to as ``NOX 
creep'') when switching from a 3 ppm sulfur gasoline to repeated, back-
to-back FTP tests using 33 ppm sulfur gasoline. The PZEV Chevrolet 
Malibu, after being aged to an equivalent of 150,000 miles, 
demonstrated emissions at a level consistent with the Tier 3 Bin 30 
NMOG+NOX standards when operated on 3 ppm sulfur fuel and 
for at least one FTP test after switching to 33 ppm certification fuel. 
Following operation over 2 FTP cycles on 33 ppm sulfur fuel, 
NOX emissions alone were more than double the Tier 3 30 mg/
mi NMOG+NOX standard.\271\ This represents a 70% 
NOX increase between 3 ppm sulfur and 33 ppm sulfur 
gasolines, approximately 2-3 times of what has been previously reported 
for similar changes in fuel sulfur level for Tier 2 and older 
vehicles.298 299
---------------------------------------------------------------------------

    \296\ Takei, Y., Kungasa, Y., Okada, M., Tanaka, T. Fujimoto, Y. 
(2000). Fuel Property Requirement for Advanced Technology Engines. 
SAE Technical Paper 2000-01-2019.
    \297\ Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel 
Sulfur on FTP NOX Emissions from a PZEV 4 Cylinder 
Application. SAE Technical Paper 2011-01-0300.
    \298\ The Effects of Ultra-Low Sulfur Gasoline on Emissions from 
Tier 2 Vehicles in the In-Use Fleet, EPA-420-R-14-002.
    \299\ Shapiro, E. (2009). National Clean Gasoline--An 
Investigation of Costs and Benefits. Published by the Alliance of 
Automobile Manufacturers.
---------------------------------------------------------------------------

    Both the Umicore and Toyota studies suggest that the emissions from 
vehicles using near-zero exhaust emissions control technology similar 
to what is expected for compliance with the Tier 3 standards are more 
sensitive to changes in gasoline sulfur content at low (sub-30 ppm) 
sulfur concentrations than technology used to meet the higher Federal 
Tier 2 and California LEV II standards. The Umicore and Toyota studies 
clearly indicate that a progressive increase in catalyst sensitivity to 
sulfur continues as exhaust emissions decrease from levels required by 
federal Tier 2 and California LEV II emissions standards to the lower 
levels required by Tier 3 emissions standards. In addition, although 
vehicles with Tier 2 technology have somewhat less sulfur sensitivity 
compared to future Tier 3 vehicles, there is still significant 
opportunity for further emissions reductions from the existing in-use 
fleet by reducing gasoline sulfur content from 30 ppm to 10 ppm. The 
results of recent testing demonstrating the potential for in-use 
emissions reductions from further gasoline sulfur control are 
summarized in Section IV.A.6.c. Recent data on the impact of gasoline 
sulfur on vehicles with exhaust emission control technologies that we 
expect to be used with Tier 3 vehicles is summarized in Sections 
IV.A.6.d and e.
c. EPA Testing of Gasoline Sulfur Effects on Tier 2 Vehicles and the 
In-Use Fleet
    Both the MSAT \300\ and Umicore \301\ studies showed the emission 
reduction potential of lower sulfur fuel on Tier 2 and later technology 
vehicles over the FTP cycle. However, assessing the potential for 
reduction on the in-use fleet requires understanding how sulfur 
exposure over time impacts emissions, and what the state of catalyst 
sulfur loading is for the typical vehicle in the field. In response to 
these data needs, EPA conducted a new study to assess the emission 
reductions expected from the in-use Tier 2 fleet with a reduction in 
fuel sulfur level from current levels.\302\ It was designed to take 
into consideration what was known from prior studies on sulfur build-up 
in catalysts over time and the effect of periodic regeneration events 
that may result from higher speed and load operation over the course of 
day-to-day driving.
---------------------------------------------------------------------------

    \300\ Chapter 6 of the Regulatory Impact Analysis for the 
Control of Hazardous Air Pollutants from Mobile Sources Final Rule, 
EPA 420-R-07-002, February 2007, last accessed on the Internet on 
12/04/2013 at the following URL: http://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P1004LNN.PDF.
    \301\ Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel 
Sulfur on FTP NOX Emissions from a PZEV 4 Cylinder 
Application. SAE Technical Paper 2011-01-0300.
    \302\ The Effects of Ultra-Low Sulfur Gasoline on Emissions from 
Tier 2 Vehicles in the In-Use Fleet, EPA-420-R-14-002.
---------------------------------------------------------------------------

    The study sample described in this analysis consisted of 93 cars 
and light trucks recruited from owners in southeast Michigan, covering 
model years 2007-9 with approximately 20,000-40,000 odometer 
miles.\303\ The makes and models targeted for recruitment were chosen 
to be representative of high sales vehicles covering a range of types 
and sizes. Test fuels were two non-ethanol gasolines with properties 
typical of certification test fuel, one at a sulfur level of 5 ppm and 
the other at 28 ppm. All emissions data was collected using the FTP 
cycle at a nominal temperature of 75 [deg]F.
---------------------------------------------------------------------------

    \303\ The NPRM modeling was based on analysis of 81 passenger 
cars and trucks. Since the NPRM, twelve additional Tier 2 vehicles 
were tested and included in the statistical analysis described in 
the docketed final report, examining the effect of sulfur on 
emissions from Tier 2 vehicles. The analysis based on the complete 
set of 93 Tier 2 vehicles is reflected in the results presented in 
this section and the emissions modeling for FRM.
---------------------------------------------------------------------------

    Using the 28 ppm test fuel, emissions data were collected from 
vehicles in their as-received state as well as following a high-speed/
load ``clean-out'' procedure consisting of two back-to-back US06 cycles 
intended to reduce sulfur loading in the catalyst. A statistical 
analysis of this data showed highly significant reductions in several 
pollutants including NOX and hydrocarbons, demonstrating 
that sulfur loadings have a large effect on exhaust catalyst 
performance, and that Tier 2 vehicles can achieve significant 
reductions based on removing, at least in part, the negative impact of 
the sulfur loading on catalyst efficiency (Table IV-6). For example, 
Bag 2 NOX emissions dropped 31 percent between the pre- and 
post-cleanout tests on 28 ppm fuel.

[[Page 23468]]



                            Table IV-6--Percent Reduction in In-Use Emissions After the Clean-Out Using 28 ppm Test Fuel \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           NOX (p-value)   THC (p-value)   CO (p-value)   NMHC (p-value)   CH4 (p-value)   PM (p-value)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bag 1...................................................  ..............  ..............   6.0% (0.0151)  ..............  ..............           15.4%
                                                                                                                                              (< 0.0001)
Bag 2...................................................           31.4%           14.9%  ..............           18.7%           14.4%  ..............
                                                                (0.0003)        (0.0118)                        (0.0131)        (0.0019)
Bag 3...................................................           35.4%           20.4%           21.5%           27.7%           10.3%           24.5%
                                                               (<0.0001)       (<0.0001)        (0.0001)       (<0.0001)       (<0.0001)       (<0.0001)
FTP Composite...........................................           11.4%            3.8%            6.8%            3.5%            6.0%           13.7%
                                                                (0.0002)        (0.0249)        (0.0107)        (0.0498)        (0.0011)       (<0.0001)
Bag 1-Bag 3.............................................  ..............  ..............            7.2%  ..............  ..............  ..............
                                                                                                (0.0656)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ The clean-out effect is not significant at [alpha] = 0.10 when no reduction estimate is provided.

    To assess the impact of lower sulfur fuel on in-use emissions, 
further testing was conducted on a representative subset of vehicles on 
28 ppm and 5 ppm fuel with accumulated mileage. A first step in this 
portion of the study was to assess the differences in the effectiveness 
of the clean-out procedure under different fuel sulfur levels. Table 
IV-7 presents a comparison of emissions immediately following (<50 
miles) the clean-out procedures at the low vs. high sulfur level. These 
results show significant emission reductions for the 5 ppm fuel 
relative to the 28 ppm fuel immediately after this clean-out; for 
example, Bag 2 NOX emissions were 34 percent lower on the 5 
ppm fuel vs. the 28 ppm fuel. This indicates that the catalyst is not 
fully desulfurized, even after a clean out procedure, as long as there 
is sulfur in the fuel. This further indicates that current sulfur 
levels in gasoline continue to have a long-term, adverse effect on 
exhaust emissions control that is not fully removed by intermittent 
clean-out procedures that can occur in day-to-day operation of a 
vehicle and demonstrates that lowering sulfur levels to 10 ppm on 
average will significantly reduce the effects of sulfur impairment on 
emissions control technology.

   Table IV-7--Percent Reduction in Exhaust Emissions When Going From 28 ppm to 5 ppm Sulfur Gasoline for the First Three Repeat FTP Tests Immediately
                                                                   Following Clean-Out
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           NOX (p-value)   THC (p-value)   CO (p-value)   NMHC (p-value)   CH4 (p-value)      PM \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bag 1...................................................            5.3%            6.8%            6.2%            5.7%           14.0%  ..............
                                                                (0.0513)        (0.0053)        (0.0083)        (0.0276)       (<0.0001)
Bag 2...................................................           34.4%           33.9%           (\a\)           26.4%           49.4%  ..............
                                                                (0.0036)       (<0.0001)                        (0.0420)       (<0.0001)
Bag 3...................................................           42.5%           36.9%           14.7%           51.7%           28.5%  ..............
                                                               (<0.0001)       (<0.0001)        (0.0041)       (<0.0001)       (<0.0001)
FTP Composite...........................................           15.0%           13.3%            8.5%           10.9%           23.6%  ..............
                                                                (0.0002)       (<0.0001)        (0.0050)        (0.0012)       (<0.0001)
Bag 1-Bag 3.............................................           (\a\)           (\a\)           (\a\)           (\a\)           (\a\)  ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ The effectiveness of clean-out cycle is not significant at [alpha] = 0.10.

    To assess the overall in-use reduction between high and low sulfur 
fuel, a mixed model analysis of all data as a function of fuel sulfur 
level and miles driven after cleanout was performed. This analysis 
found highly significant reductions for several pollutants, as shown in 
Table IV-8. Reductions for Bag 2 NOX were particularly high, 
estimated at 52 percent between 28 ppm and 5 ppm overall. For all 
pollutants, the model fitting did not find a significant miles-by-
sulfur interaction, suggesting the relative differences were not 
dependent on miles driven after clean-out.

                          Table IV-8--Percent Reduction in Emissions From 28 ppm to 5 ppm Fuel Sulfur on In-Use Tier 2 Vehicles
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                           NOX+NMOG (p-
                                           NOX (p-value)   THC (p-value)   CO (p-value)   NMHC (p-value)   CH4 (p-value)      value)          PM \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bag 1...................................            7.1%            9.2%            6.7%            8.1%           16.6%             N/A  ..............
                                                (0.0216)        (0.0002)        (0.0131)        (0.0017)      (< 0.0001)
Bag 2...................................           51.9%           43.3%             (a)           42.7%           51.8%             N/A  ..............
                                              (< 0.0001)      (< 0.0001)                        (0.0003)      (< 0.0001)
Bag 3...................................           47.8%           40.2%           15.9%           54.7%           29.2%             N/A  ..............
                                              (< 0.0001)      (< 0.0001)        (0.0003)      (< 0.0001)      (< 0.0001)
FTP Composite...........................           14.1%           15.3%            9.5%           12.4%           29.3%           14.4%  ..............
                                                (0.0008)      (< 0.0001)      (< 0.0001)      (< 0.0001)      (< 0.0001)      (< 0.0001)
Bag 1-Bag 3.............................           (\a\)            5.9%           (\a\)           (\b\)           (\b\)             N/A  ..............
                                                                (0.0074)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Sulfur level not significant at [alpha] = 0.10.
\b\ Inconclusive because the mixed model did not converge.


[[Page 23469]]

    Major findings from this study include:
     Largely reversible sulfur loading is occurring in the in-
use fleet of Tier 2 vehicles and has a measureable effect on emissions 
of NOX, hydrocarbons, and other pollutants of interest.
     The effectiveness of high speed/load procedures in 
restoring catalyst efficiency is limited when operating on higher 
sulfur fuel.
     Reducing fuel sulfur levels from current levels to levels 
in the range of the Tier 3 gasoline sulfur standards is expected to 
achieve significant reductions in emissions of NOX, 
hydrocarbons, and other pollutants of interest in the current in-use 
fleet.
     Assuming that the emissions impacts vs. gasoline sulfur 
content are approximately linear, changing gasoline sulfur content from 
30 ppm to 10 ppm would result in NMOG+NOX emissions 
decreasing from 52 mg/mi to 45 mg/mi, respectively (a 13% decrease), 
and NOX emissions decreasing from 19 mg/mi to 16 mg/mi, 
respectively (a 16% decrease), for the vehicles in the study.
    To evaluate the robustness of the statistical analyses assessing 
the overall in-use emissions reduction between operation on high and 
low sulfur fuel (Table IV-8), a series of sensitivity analyses were 
performed to assess the impacts on study results of measurements from 
low-emitting vehicles and influential vehicles, as documented in detail 
in the report.\304\ The sensitivity analyses showed that the magnitude 
and the statistical significance of the results were not impacted and 
thus demonstrated that the results are statistically robust. We also 
subjected the design of the experiment and data analysis to a 
contractor-led independent peer-review process in accordance with EPA's 
peer review guidance. The results of the peer review \305\ \306\ 
largely supported the study design, statistical analyses, and the 
conclusions from the program and raised only minor concerns that have 
not changed the overall conclusions and have subsequently been 
addressed in the final version of the report.\307\
---------------------------------------------------------------------------

    \304\ The Effects of Ultra-Low Sulfur Gasoline on Emissions from 
Tier 2 Vehicles in the In-Use Fleet, EPA-420-R-14-002.
    \305\ Peer Review of the Effects of Fuel Sulfur Level on 
Emissions from the In-Use Tier 2 Vehicles, EPA-HQ-OAR-2011-0135-
1847.
    \306\ EPA In-Use Sulfur Report--Response to Peer-Review 
Comments, EPA-HQ-OAR-2011-0135-1848.
    \307\ The Effects of Ultra-Low Sulfur Gasoline on Emissions from 
Tier 2 Vehicles in the In-Use Fleet, EPA-420-R-14-002.
---------------------------------------------------------------------------

    Overall, the reductions found in this study are in agreement with 
other low sulfur studies conducted on Tier 2 vehicles, namely MSAT and 
Umicore studies mentioned above, in terms of the magnitude of 
NOX and HC reductions when switching from 28 ppm to 5 ppm 
fuel.\308\ We have reviewed the results of the emission effects study 
performed by SGS, which was included with API's comments on the Tier 3 
proposal, and have concluded that these results are also consistent 
with the findings of EPA's Tier 2 in-use study, specifically that 
exhaust emissions performance is sensitive to fuel sulfur level.\309\ 
The SGS study also suggests that negative effects of exposure to a 
somewhat higher sulfur level (80 ppm in this case) are largely 
reversible for Tier 2 vehicles, meaning that reducing fuel sulfur 
levels nationwide will bring significant immediate benefits by reducing 
emissions of the existing fleet. For further details regarding the Tier 
2 In-Use Gasoline Sulfur Effects Study, see the final report.\310\
---------------------------------------------------------------------------

    \308\ Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel 
Sulfur on FTP NOX Emissions from a PZEV 4 Cylinder 
Application. SAE Technical Paper 2011-01-0300.
    \309\ American Petroleum Institute. 2013. Supplemental Comments 
of the American Petroleum Institute. Available in the docket for 
this final rule, docket no. EPA-HQ-OAR-2011-0135.
    \310\ The Effects of Ultra-Low Sulfur Gasoline on Emissions from 
Tier 2 Vehicles in the In-Use Fleet, EPA-420-R-14-002.
---------------------------------------------------------------------------

    As a follow-on phase to the Tier 2 in-use study, EPA analyzed five 
vehicles \311\ certified to Tier 2 Bin 4, LEV II ULEV and LEV II SULEV 
exhaust emissions standards to assess the gasoline sulfur sensitivity 
of Tier 2 and California LEV II vehicles with emission levels 
approaching or comparable to the Tier 3 standards. The analysis found 
that these low-emitting Tier 2 vehicles showed similar or greater 
sensitivity to fuel sulfur levels compared to the original Tier 2 test 
fleet--for example, a 24 percent reduction in FTP composite 
NOX emissions when sulfur is reduced from 28 ppm to 5 
ppm.\312\ Test results discussed below in section IV.A.6.d also confirm 
that there is significantly increased sensitivity of exhaust emissions 
to gasoline sulfur as vehicle technologies advance towards exhaust 
emissions approaching near-zero emissions (e.g., Tier 3 Bin 50 and 
lower). The impact of fuel sulfur on vehicles with exhaust emission 
control technologies that we expect to be used with Tier 3 vehicles is 
summarized in the next two sections (Preamble IV.A.6.d and e).
---------------------------------------------------------------------------

    \311\ The make and model of the tested vehicles are Honda 
Crosstour, Chevrolet Malibu, Chevrolet Silverado, Ford Focus and 
Subaru Outback.
    \312\ The Effects of Ultra-Low Sulfur Gasoline on Emissions from 
Tier 2 Vehicles in the In-Use Fleet, EPA-420-R-14-002.
---------------------------------------------------------------------------

    EPA believes that the studies by EPA and others described in this 
section strongly support our conclusion that reducing gasoline sulfur 
content to a 10 ppm average will result in significant exhaust 
emissions reductions from the current in-use fleet. However, some 
commenters have expressed concerns about the relevance and 
appropriateness of the data, as well as the conclusions drawn from 
them. The Summary and Analysis of Comments document, available in the 
docket for this rulemaking, provides our responses to those comments.
d. Testing of Gasoline Sulfur Effects on Vehicles With Tier 3/LEV III 
Technology
    The Tier 3 fleet average exhaust emissions standards of 30 mg/mi 
NMOG+NOX will require large reductions of emissions across a 
broad range of light-duty vehicles and trucks with differing degrees of 
utility. Previous studies of sulfur impacts on extremely low exhaust 
emission vehicles (e.g., Toyota, Umicore) were limited to mid-size or 
smaller light-duty vehicles. There are currently no LDT3 or any LDT4 
vehicles certified at or below Federal Tier 2 Bin 3 or to the 
California LEV II SULEV exhaust emission standards with the exception 
of a single hybrid electric SUV. At the time of the Tier 3 NPRM, EPA 
was not aware of any existing data demonstrating the impact of changes 
in gasoline sulfur content on larger vehicles with technology 
comparable to what would be expected for compliance with Tier 3 exhaust 
emission standards. In their supplemental comments to the Tier 3 
proposal, API criticized EPA's reliance on emissions data from older 
vehicles that were not considered to be examples of future Tier-3-like 
vehicles. In order to further evaluate this issue, the Agency initiated 
a test program at EPA's National Vehicle and Fuel Emissions Laboratory 
(NVFEL) in Ann Arbor, Michigan. The Agency obtained a heavy-light-duty 
truck and applied changes to the design and layout of the exhaust 
catalyst system and to the calibration of the engine management system 
consistent with our engineering analyses of technology necessary to 
meet Tier 3 Bin 30 emissions with a 20 to 40% compliance margin at 
150,000 miles. EPA also requested that Umicore loan the Agency the 
vehicle tested in their study to undergo further evaluation of gasoline 
sulfur impacts on exhaust emissions. In addition, Ford Motor Company 
completed testing of fuel sulfur effects on a Tier 3/LEV III 
developmental heavy-light-duty truck and submitted a summary report of 
their

[[Page 23470]]

findings as part of their supplemental comments to the Tier 3 NPRM. The 
results of these three test programs are summarized below.
i. Ford Motor Company Tier 3 Sulfur Test Program
    Ford Motor Company recently completed testing of a heavy-light-duty 
truck (i.e., between 6,000 and 8,500 pounds GVWR) under development to 
meet the Tier 3 Bin 50 standards on two different fuel sulfur levels 
and submitted the resulting data to EPA as part of its supplemental 
comments.313 314 The test results from this vehicle are 
particularly important when considering the following factors:
---------------------------------------------------------------------------

    \313\ Ford Motor Company. 2013. ``Quality Changes Needed to Meet 
Tier 3 Emission Standards and Future Greenhouse Gas Requirements.'' 
Attachment 2: ``Tier 3 Sulfur Test Program--Ford Motor Company 
Summary Report.'' Available within EPA Docket for this final rule, 
EPA-HQ-2011-0135.
    \314\ Dominic DiCicco, Ford Motor Company. 2013. ``Additional 
data as requested. RE: Ford Supplemental Comments on Tier 3.'' 
Available within EPA Docket for this final rule, EPA-HQ-2011-0135.
---------------------------------------------------------------------------

     These are the first detailed emissions data submitted by a 
vehicle manufacturer to the Agency demonstrating emissions of a heavy-
light-duty-truck consistent with Tier 3 Bin 50 or lower emissions 
levels.
     The truck tested uses a version of Ford's 2.0 L GTDI 
engine, an engine with high BMEP (approximately 23-bar) that can allow 
significant engine displacement downsizing while maintaining the 
truck's utility. This is a key enabling GHG reduction strategy analyzed 
by EPA in the 2017-2025 GHG Final Rule.\315\
---------------------------------------------------------------------------

    \315\ See 77 FR 62840-62862, October 15, 2012; and Joint 
Technical Support Document: Final Rulemaking for 2017-2025 Light-
Duty Vehicle Greenhouse Gas Emission Standards and Corporate Average 
Fuel Economy Standards (EPA-420-R-12-901), August 2012, Chapter 
3.4.1.7-3.4.1.8 (pages 3-88--3-95).
---------------------------------------------------------------------------

     The vehicle was specifically under development by a 
vehicle manufacturer with an engineering target of meeting Tier 3 Bin 
50 and LEV III ULEV50 exhaust emissions standards.
Turbocharged, downsized engines are key technologies within Ford's 
strategy to reduce GHG emissions.\316\ EPA expects that trucks with 
configurations similar to this developmental Ford Explorer (downsized 
engines with reduced GHG emissions and very low emissions of 
NMOG+NOX) will become increasingly prevalent within the 
timeframe of the implementation of the Tier 3 regulations.
---------------------------------------------------------------------------

    \316\ Ford Motor Company, 2012. ``Sustainability 2011/2012--
Improving Fuel Economy.'' Accessed on the Internet on 11/21/2013 at: 
http://corporate.ford.com/microsites/sustainability-report-2011-12/environment-products-plan-economy. Available within EPA Docket for 
this final rule, EPA-HQ-2011-0135.
---------------------------------------------------------------------------

    The developmental truck used close-coupling of both catalyst 
substrates and relatively high PGM loading (150 g/ft\3\). Ford used 
accelerated aging of the catalysts and O2 sensors to an 
equivalent of 150,000 miles (the Tier 3 full useful life). The 
developmental hardware and engine management calibration configuration 
of this truck was designed to meet federal Tier 3 Bin 50 and California 
LEV III ULEV50 standards of 50 mg/mi NMOG+NOX at 150,000 
miles. The emissions data submitted by Ford included NOX and 
NMHC emissions during operation on E10 California LEV III certification 
fuel at two different sulfur levels, 10 ppm and 26.5 ppm. Ford did not 
provide NMOG emissions data but there was sufficient information for 
EPA to calculate NMOG emissions from the provided NMHC data using 
calculations from Title 40 CFR 1066.665.
    The truck demonstrated average FTP NMOG+NOX emissions of 
37 mg/mi on the 10 ppm E10 California LEV III fuel, emissions that are 
consistent with compliance with Bin 50 and ULEV50 standards with a 
reasonable margin of compliance (emissions at approximately 70% of the 
standard). Retesting of the same vehicle on LEV3 E10 blended \317\ to 
26.5 ppm S resulted in average NMOG+NOX emissions of 53 mg/
mi, 6% above the Tier 3 Bin 50 standard. Ford found a high level of 
statistical significance with respect to the increase of emissions with 
increasing fuel sulfur. Assuming a linear effect of sulfur on emissions 
performance, NMOG+NOX emissions would be approximately 56 
mg/mi at 30 ppm sulfur, which is approximately 12% above the Bin 50 
exhaust emissions standard. This also represents an increase in 
NMOG+NOX emissions of 53% with an approximate doubling of 
NOX emissions and a 13% increase in NMOG for 30 ppm sulfur 
gasoline vs. 10 ppm sulfur gasoline.
---------------------------------------------------------------------------

    \317\ Ford used the same tert-butyl sulfide fuel sulfur 
additives used within the EPA testing in IV.A.6.c and d.
---------------------------------------------------------------------------

    The advanced technology Ford truck, which was shown to be capable 
of complying with the Tier 3 Bin 50 standard with a reasonable margin 
of compliance on 10 ppm sulfur gasoline, in effect reverted to 
approximately LEV II ULEV exhaust emissions levels when tested on 
higher sulfur gasoline, equivalent to the previous level of emissions 
control to which earlier models of this vehicle were certified for MY 
2013. The effect of increasing gasoline sulfur levels from 10 ppm to 30 
ppm \318\ on this vehicle essentially negated the entire benefit of the 
advances in emissions control technology that were applied by the 
vehicle manufacturer to meet developmental goals for compliance with 
Tier 3 standards. This clearly indicates, for this vehicle model using 
technology representative of what would be expected for compliance with 
Tier 3 Bin 50 and post 2017 GHG standards, reducing gasoline sulfur to 
10 ppm is needed for the advances in technology to achieve their 
intended effectiveness in reducing NMOG+NOX emissions. The 
advances in vehicle technology and the reduction in gasoline sulfur 
clearly are both needed to achieve the emissions reductions called for 
by Tier 3.
---------------------------------------------------------------------------

    \318\ Emissions at 30 ppm sulfur estimated assuming 
approximately linear emissions effects between 10, 26.5 and 30 ppm 
gasoline sulfur levels.
---------------------------------------------------------------------------

ii. EPA Re-Test of Umicore 2009 Chevrolet Malibu PZEV
    Ball et al. of Umicore Autocat USA, Inc. previously studied the 
impact of gasoline fuel sulfur levels of 3 ppm and 33 ppm on the 
emissions of a 2009 Chevrolet Malibu PZEV.\319\ In their supplemental 
comments, API commented that the composition of the two test fuels 
outside of sulfur content was not held constant and thus the exhaust 
emissions differences attributed to the difference in gasoline sulfur 
levels may have been due to other fuel property differences. For 
example, the 3 ppm fuel used by Ball et al. was nonoxygenated EEE Clear 
test fuel (essentially, Tier 2 Federal certification gasoline except 
with near-zero sulfur) while the 33 ppm fuel was an oxygenated 
California Phase 2 LEV II certification fuel. Thus it was not entirely 
clear if the changes in NOX emissions observed between tests 
with the two fuels were significantly impacted by fuel composition 
variables other than gasoline sulfur content. EPA obtained the same 
test vehicle from Umicore for retesting at the EPA NVFEL facility using 
the 5 ppm and 28 ppm sulfur E0 test fuels and vehicle test procedures 
used in EPA gasoline sulfur effects testing on Tier 2 vehicles (see 
Section IV.6.b).
---------------------------------------------------------------------------

    \319\ Ball, D., Clark, D., Moser, D. (2011). Effects of Fuel 
Sulfur on FTP NOX Emissions from a PZEV 4 Cylinder 
Application. SAE Technical Paper 2011-01-0300. Available in the 
docket for this final rule.
---------------------------------------------------------------------------

    In EPA's retest of the 2009 Chevrolet Malibu PZEV, when sulfur was 
the only difference between the test fuels, the gasoline with higher 
sulfur resulted in significantly higher increases in NOX 
emissions with increasing fuel sulfur content than was observed in the

[[Page 23471]]

previous testing by Ball et al. at Umicore. Assuming emissions impacts 
vs. gasoline sulfur content are approximately linear, the original data 
from Ball et al. would have resulted in a predicted increase in 
NOX emissions of approximately 40% when increasing gasoline 
sulfur from 10 ppm to 30 ppm. The EPA re-testing of the same vehicle 
that controlled for other fuel composition differences resulted in a 
predicted increase in NOX emissions of 93% when increasing 
gasoline sulfur from 10 ppm to 30 ppm, with NOX emissions 
approximately doubling from 22 g/mi to 43 g/mi, with no statistically 
significant difference in NMOG emissions and with an increase in 
NMOG+NOX emissions of 56%. The approximate doubling in 
NOX emissions with the Malibu PZEV between 10 ppm and 30 ppm 
sulfur was nearly identical to the results found during testing of the 
Tier 3 Bin 50 developmental Ford Explorer discussed above. The results 
confirm that fuel compositional differences other than sulfur may have 
impacted exhaust emissions results in the Ball et al. study by 
underreporting a substantial portion of the effect of increased sulfur 
on NOX emissions. When controlling for other fuel 
composition differences, the resultant increase in NOX 
exhaust emissions due to increasing gasoline sulfur was more than 
double that observed in the original Ball et al. study. The observed 
increase in NMOG+NOX emissions during EPA testing of the 
Malibu PZEV was also comparable to results found with the developmental 
Tier 3 Bin 50 Ford Explorer. There was also a much higher increase in 
NOX and NMOG+NOX emissions for both the Malibu 
PZEV and the Tier 3 Bin 50 Explorer with increased gasoline sulfur than 
was observed with Tier 2 vehicles in the EPA Tier 2 in-use study. (See 
also Chapter 1.2.4 of the RIA)
iii. EPA Prototype Tier 3 Heavy-Light-Duty Truck Test Program
    EPA purchased a 2011 Chevrolet Silverado heavy-light-duty (LDT4) 
pickup truck with a developmental goal of modifying the truck to 
achieve exhaust emissions consistent with compliance with the Tier 3 
Bin 30 emissions standards. The truck was equipped with a 5.3L V8 with 
General Motors' ``Active Fuel Management'' cylinder deactivation 
system. This particular truck was chosen in part because cylinder 
deactivation is a key technology for light-truck compliance with future 
GHG standards and in part because it achieved very low emissions in its 
OEM, Tier 2-compliant configuration (certified to Tier 2 Bin 4). A 
prototype exhaust system was obtained from MECA consisting of high-
cell-density (900 cpsi) thin-wall (2.5 mil), high-PGM, close-coupled 
Pd-Rh catalysts with an additional under-body Pd-Rh catalyst. The total 
catalyst volume was approximately 116 in\3\ with a specific PGM loading 
of 125 g/ft\3\ and approximate loading ratio of 0:80:5 (Pt:Pd:Rh). 
Third-party (non-OEM) EMS calibration tools were used to modify the 
powertrain calibration in an effort to improve catalyst light-off 
performance. The final test configuration used approximately 4 degrees 
of timing retard and approximately 200 rpm higher idle speed relative 
to the OEM configuration during and immediately following cold-start. 
The exhaust catalyst system and HEGO sensors were bench aged to an 
equivalent 150,000 miles using standard EPA accelerated catalyst bench-
aging procedures.\320\ The truck was tested on California LEV III E10 
certification fuel at 9 and 29 ppm gasoline sulfur levels.
---------------------------------------------------------------------------

    \320\ U.S. Code of Federal Regulations, Title 40, Sec.  86.1823-
08 ``Durability demonstration procedures for exhaust emissions.''
---------------------------------------------------------------------------

    The EPA Tier 3 prototype Silverado achieved NMOG+NOX 
emissions of 18 mg/mi on the 9 ppm S fuel. The NMOG+NOX 
emissions were approximately 60% of the Bin 30 standard and thus are 
consistent with meeting the Tier 3 Bin 30 exhaust emissions standard 
with a moderate compliance margin. NMOG+NOX emissions 
increased to 29 mg/mi on the 29 ppm S fuel and one out of four tests 
exceeded the Bin 30 exhaust emissions standards. NMOG+NOX 
emissions would be at 19 mg/mi and 30 mg/mi with 10 ppm and 30 ppm 
gasoline sulfur, respectively, assuming a linear effect of sulfur on 
emissions performance. This represents an increase in 
NMOG+NOX emissions of approximately 55%, comparable to 
increases observed with both the EPA-tested Chevrolet Malibu PZEV and 
the developmental Tier 3 Bin 50 Ford Explorer. The impact of increased 
gasoline sulfur on NMOG+NOX emissions was due to comparable 
increases (on a percentage basis) in both NMOG and NOX 
emissions. This effect of gasoline sulfur on the Prototype Silverado 
truck's emissions differed from the sulfur impacts observed on the 
developmental Ford Explorer, which primarily affected NOX 
emissions, and the Malibu PZEV, where the impact was entirely on 
NOX emissions.
e. Gasoline Sulfur Level Necessary for New Light-Duty Vehicles To 
Achieve Tier 3 Exhaust Emissions Standards
    Meeting Tier 3 NMOG+NOX standards will require major 
reductions in exhaust emissions across the entire fleet of new light-
duty vehicles. As discussed in previous sections, the Tier 3 program 
will require reductions in fleet average NMOG+NOX emissions 
of over 80 percent for the entire fleet of light-duty vehicles and 
light-duty trucks. This significant level of fleet average emission 
reduction will require reductions from all parts of the fleet, 
including vehicles models with exhaust emissions currently at or near 
the level of the fully phased-in Tier 3 FTP NMOG+NOX fleet 
average standard of 30 mg/mi.
    Compliance with the more stringent Tier 3 fleet average standards 
will require vehicle manufacturers to certify a significant amount of 
vehicles to bin standards that are below the Bin 30 fleet average 
standard to offset other vehicles that are certified to bin standards 
that remain somewhat above the Bin 30 fleet average even after 
significantly reducing their emissions. At the same time, the 
stringency of the Tier 3 standards will push almost all vehicle models 
to be close to or below the Bin 30 fleet average standard. There are 
only 2 compliance bins below Bin 30, i.e., Bin 20 and Bin 0, available 
to offset emissions of vehicles certifying above Bin 30. There is also 
very limited ability for vehicle manufacturers to certify vehicles 
below the stringent Tier 3 fleet average exhaust emissions standard 
since Bin 20 and Bin 30 standards for individual vehicle certification 
test groups are approaching the engineering limits of what can be 
achieved for vehicles using an internal combustion engine and Bin 0 can 
only be achieved by electric-only vehicle operation. The result is that 
there is a very limited ability to offset sales of vehicles certified 
above the 30 mg/mi fleet average emission standard. This means in 
general that vehicle models currently with higher emissions will have 
to achieve significant emissions reductions to minimize the gap, if 
any, between their certified bin levels under Tier 3 and the Tier 3 Bin 
30 fleet average standard, and vehicle models currently at or below Bin 
30 will also have to achieve further emissions reductions under Tier 3 
to offset the vehicles that remain certified to bin standards somewhat 
above Bin 30l. The end result is a need for major reductions from all 
types of vehicles in the light-duty fleet, including those above as 
well as most vehicles that are already near, at, or

[[Page 23472]]

below the Tier 3 Bin 30 fleet average standard.
    Achieving exhaust emissions reductions of over 80% for the fleet, 
with major reductions across all types of light-duty vehicles and 
light-duty trucks, will be a major technological challenge. Vehicles 
already have made significant advances in controlling cold start 
emissions and maximizing exhaust catalyst efficiency (e.g., improving 
warm-up and catalyst light-off after cold starts and maintaining very 
high catalyst efficiency once warmed up) in order to meet Tier 2 and 
LEV II emissions standards. There are no ``low-hanging fruit'' 
remaining for additional NMOG+NOX reductions from light-duty 
vehicles from a technology perspective, meaning that vehicle 
manufacturers cannot merely change one aspect of emissions control and 
thereby achieve all of the required reductions. Instead, compliance 
with light-duty Tier 3 exhaust emissions standards will require 
significant improvements in all areas of emissions control--with 
further improvements in fuel-system management and mixture preparation 
during cold start, improvements in achieving catalyst light-off 
immediately after cold start, and improved catalyst efficiency during 
stabilized, fully-warmed-up conditions. Manufacturers will need further 
improvements in each of these areas with nearly every vehicle in order 
to comply with the fleet-average Tier 3 standards.
    From a technology perspective, the most likely control strategies 
will involve using exhaust catalyst technologies and powertrain 
calibration primarily focused on reducing cold-start emissions of NMOG, 
and on reducing both cold-start and warmed-up (running) emissions of 
NOX. An important part of this strategy, particularly for 
larger vehicles having greater difficulty achieving cold-start NMOG 
emissions control, will be to reduce NOX emissions to near-
zero levels. This will involve controlling engine-out NOX 
emissions during cold start, shortening the cold start period prior to 
catalyst light-off of NOX reduction reactions, and better 
controlling NOX emissions once the catalyst is fully warmed 
up. This is needed to allow a sufficient NMOG compliance margin so that 
vehicles can meet the combined NMOG+NOX emissions standards 
for their full useful life.
    While significant NMOG+NOX emissions reductions can be 
achieved from better control of cold start NMOG emissions, there are 
practical engineering limits to NMOG control for larger displacement 
vehicles (e.g., large light-duty trucks with significant payload and 
trailer towing capabilities). This is based in part on the impact on 
NMOG emissions of the larger engine surface-to-volume ratio and 
resultant heat conduction from the combustion chamber during warm-up. 
There are also tradeoffs between some cold-start NMOG controls and 
cold-start NOX control. For example, secondary air injection 
and/or leaner fueling strategies improve catalyst light-off for NMOG 
after a cold-start but also place OSC components in an oxidation state 
that limits potential for NOX reduction and thus often 
result in higher cold-start NOX emissions. Some applications 
achieve lower NMOG+NOX emissions without the use of 
secondary air injection by careful calibration, changes to the catalyst 
formulation and balancing of catalyst HC and NOX activity. 
The EPA Prototype Silverado and the developmental Ford Explorer are 
specific examples of this approach.
    Because of engineering limitations with large vehicles, heavy-
light-trucks and other vehicles with significant utility, we expect 
many applications will need close to 100% efficiency in NOX 
control under fully warmed-up conditions and very fast light-off of 
NOX reduction reactions over the exhaust catalyst almost 
immediately after cold-start for those applications. This will require 
significant improvements in catalytic and engine-out NOX 
reduction compared with Tier 2 vehicles and will be especially 
important for heavier vehicles due to the challenges of achieving low 
NMOG.
    These technology improvements--improving warm-up and catalyst 
light-off after cold starts and maintaining very high catalyst 
efficiency--once warmed up--all rely on 10 ppm average sulfur fuel to 
achieve the very significant emissions reductions required for the 
fleet to achieve the Tier 3 Bin 30 fleet average emissions standard. 
The evidence from the test results and specific vehicle examples 
discussed above clearly indicate that leaving the gasoline sulfur level 
at 30 ppm would largely negate the benefits of key technology 
improvements expected to be used for compliance with Tier 3 exhaust 
emissions standards. Without the lower 10 ppm gasoline sulfur content, 
the Tier 3 exhaust fleet average emissions standards would not be 
achievable across the broad range of vehicles that must achieve 
significant exhaust emissions reductions.
    One aspect of the need for sulfur levels of 10 ppm average stems 
from the fact that achieving the Tier 3 emission standards will require 
very careful control of the exhaust chemistry and exhaust temperatures 
to ensure high catalyst efficiency. The impact of sulfur on OSC 
components in the catalyst makes this a challenge even at relatively 
low (10 ppm) gasoline sulfur levels. NOX conversion by 
exhaust catalysts is strongly influenced by the OSC components like 
ceria. Ceria sulfation may play an important role in the large 
degradation of NOX emission control with increased fuel 
sulfur levels observed in the MSAT, Umicore and EPA Tier 2 In-Use 
Gasoline Sulfur Effects studies and the much more severe NOX 
emissions degradation observed in recent test data from PZEV and 
prototype/developmental Tier 3/LEV III vehicles.\321\
---------------------------------------------------------------------------

    \321\ Heck, R.M., Farrauto, R.J. (2002). Chapter 6: Automotive 
Catalyst in Catalytic Air Pollution Control, 2nd Edition. John Wiley 
and Sons, Inc.
---------------------------------------------------------------------------

    The importance of lower sulfur gasoline is also demonstrated by the 
fact that vehicles certified to California SULEV are typically 
certified to higher bins for the federal Tier 2 program. Light-duty 
vehicles certified to CARB SULEV and federal Tier 2 Bin 2 exhaust 
emission standards accounted for approximately 3.1 percent and 0.4 
percent, respectively, of vehicle sales for MY2009. Light-duty vehicles 
certified to SULEV under LEV II are more typically certified federally 
to Tier 2 Bin 3, Bin 4 or Bin 5, and vehicles certified to SULEV and 
Tier 2 Bins 3-5 comprised approximately 2.5 percent of sales for 
MY2009. In particular, nonhybrid vehicles certified in California as 
SULEV are not certified to federal Tier 2 Bin 2 emissions standards 
even though the numeric limits for NOX and NMOG are shared 
between the California LEV II and federal Tier 2 programs for SULEV and 
Bin 2. Confidential business information shared by the auto companies 
indicate that the primary reason is an inability to demonstrate 
compliance with SULEV/Bin 2 emission standards after vehicles have 
operated in-use on gasoline with greater than 10 ppm sulfur and with 
exposure to the higher sulfur gasoline sold nationwide. While vehicles 
certified to the LEV II SULEV and Tier 2 Bin 2 standards both 
demonstrate compliance using certification gasoline with 15-40 ppm 
sulfur content, in-use compliance of SULEV vehicles in California 
occurs after significant, sustained operation on gasoline with an 
average of 10 ppm sulfur and a maximum cap of 30 ppm sulfur while 
federally certified vehicles under the Tier 2 program operate on 
gasoline with an average of 30 ppm sulfur and a maximum cap of 80 ppm 
sulfur. Although the SULEV and Tier 2 Bin 2

[[Page 23473]]

standards are numerically equivalent, the increased sulfur exposure of 
in-use vehicles certified under the federal Tier 2 program results in a 
need for a higher emissions compliance margin to take into account the 
impact of in-use gasoline sulfur on full useful life vehicle emissions. 
As a result, vehicles certified to California SULEV typically certify 
to emissions standards under the federal Tier 2 program that are 1-2 
certification bins higher (e.g., SULEV certified federally as Tier 2 
Bin 3 or Bin 4) in order to ensure in-use compliance with emissions 
standards out to the full useful life of the vehicle when operating on 
higher-sulfur gasoline.
    There are currently no LDTs larger than LDT2 with the exception of 
a single hybrid electric SUV certified to Tier 2 Bin 2 or SULEV 
emissions standards. We expect that additional catalyst technologies, 
for example increasing catalyst surface area (volume or substrate cell 
density) and/or increased PGM loading, will need to be applied to 
larger vehicles in order to achieve the catalyst efficiencies necessary 
to comply with the Tier 3 standards, and any sulfur impact on catalyst 
efficiency will have a larger impact on vehicles and trucks that rely 
more on very high catalyst efficiencies in order to achieve very low 
emissions. The vehicle emissions data referenced in Section IV.A.6.d 
represents the only known data on non-hybrid vehicles spanning a range 
from mid-size LDVs to heavy-light-trucks at the very low criteria 
pollutant emissions levels that will be needed to comply with the Tier 
3 exhaust emissions standards. The developmental Ford Explorer, 
Chevrolet Malibu PZEV and EPA prototype Chevrolet Silverado vehicles 
described in section IV.A.6.c also represent a range of different 
technology approaches to both criteria pollution control and GHG 
reduction (e.g., use of secondary air vs. emphasizing cold-start 
NOX control, use of engine downsizing via turbocharging vs. 
cylinder deactivation for GHG control, etc.) and represent a broad 
range of vehicle applications and utility (mid-size LDV, LDT3, LDT4). 
All of the vehicles with Tier 3/LEV III technology demonstrated greater 
than 50% increases in NMOG+NOX emissions when increasing 
gasoline sulfur from 10 ppm to 30 ppm. Two of the vehicles showed a 
doubling of NOX emissions when increasing gasoline sulfur 
from 10 ppm to 30 ppm. Both of the heavy-light-duty trucks with 
specific engineering targets of meeting Tier 3 emissions were capable 
of meeting their targeted emission standards with a sufficient 
compliance margin on 10 ppm sulfur gasoline and could not meet their 
targeted emissions standards or could not achieve a reasonable 
compliance margin when tested with 30 ppm sulfur gasoline.
    The negative impact of gasoline sulfur on catalytic activity and 
the resultant loss of exhaust catalyst effectiveness to chemically 
reduce NOX and oxidize NMOG occur across all vehicle 
categories. However, the impact of gasoline sulfur on the effectiveness 
of exhaust catalysts to control NOX emissions in the fully-
warmed-up condition is particularly of concern for larger vehicles (the 
largest LDVs and LDT3s, LDT4s, and MDPVs). Manufacturers face the most 
significant challenges in reducing cold-start NMOG emissions for these 
vehicles. Because of the need to reach near-zero NOX 
emissions levels in order to offset engineering limitations on further 
NMOG exhaust emissions control with these vehicles, any significant 
degradation in NOX emissions control over the useful life of 
the vehicle would likely prevent some if not most larger vehicles from 
reaching a combined NMOG+NOX level low enough to comply with 
the 30 mg/mi fleet-average standard. Any degradation in catalyst 
performance due to gasoline sulfur would reduce or eliminate the margin 
necessary to ensure in-use compliance with the Tier 3 emissions 
standards. Certifying to a useful life of 150,000 miles versus the 
current 120,000 miles will further add to manufacturers' compliance 
challenge for Tier 3 large light trucks (See Section IV.A.7.c below for 
more on the useful life requirements.) These vehicles represent a 
sufficiently large segment of light-duty vehicle sales now and for the 
foreseeable future such that their emissions could not be sufficiently 
offset (and thus the fleet-average standard could not be achieved) by 
certifying other vehicles to bins below the fleet average standard.
    As discussed above, achieving Tier 3 levels as an average across 
the light-duty fleet will require fleet wide reductions of 
approximately 80%. This will require significant reductions from all 
light duty vehicles, with the result that some models and types of 
vehicles will be at most somewhat above the Tier 3 level, and all other 
models will be at or somewhat below Tier 3 levels. Achieving these 
reductions presents a major technology challenge. The required 
reductions are of a magnitude that EPA expects manufacturers to employ 
advances in technology in all of the relevant areas of emissions 
control--reducing engine-out emissions, reducing the time to catalyst 
lightoff, improving exhaust catalyst durability at 120,000 or 150,000 
miles and improving efficiency of fully warmed up exhaust catalysts. 
All of these areas of emissions control need to be improved, and 
gasoline sulfur reduction to a 10 ppm average is a critical part of 
achieving Tier 3 levels through these emissions control technology 
improvements.
    The use of 10 ppm average sulfur fuel is an essential part of 
achieving Tier 3 levels while applying an array of advancements in 
emissions control technology to the light-duty fleet. The testing of 
Tier 2 and Tier 3 type technology vehicles, as well as other 
information, shows that sulfur has a very large impact on the 
effectiveness of the control technologies expected to be used in Tier 3 
vehicles. Without the reduction in sulfur to a 10 ppm average, the 
major technology improvements projected under Tier 3 would only result 
in a limited portion of the emissions reductions needed to achieve Tier 
3 levels. For example, without the reduction in sulfur from a 30 ppm to 
10 ppm average, the technology improvements would not come close to 
achieving Tier 3 levels. In some cases this may result in the same 
effectiveness as the current Tier 2 technology and achieve only 
approximately Tier 2 levels of exhaust emissions control.
    Achieving Tier 3 levels without a reduction in sulfur to 10 ppm 
levels would only be possible if there were technology improvements 
significantly above and beyond those discussed above. Theoretically, 
without reducing sulfur levels to 10 ppm average, emissions control 
technology improvements would need to provide upwards of twice as much, 
and in some cases significantly more than twice as much, emissions 
control effectiveness as the Tier 3 technology improvements discussed 
above in Section IV.A.6.d. EPA has not identified technology 
improvements that could provide such a large additional increase in 
emissions control effectiveness, across the light-duty fleet, above and 
beyond that provided by the major improvements in technology discussed 
above, without any additional gasoline reductions in gasoline sulfur 
content. The impact of sulfur reduction on the effectiveness of the 
available technology improvements plays such a large role in achieving 
the Tier 3 levels that there would be no reasonable basis to expect 
that technology would be available, at the 30 ppm sulfur level, to fill 
the emission control gap left from no sulfur reduction, and achieve the 
very significant fleetwide reductions needed to meet the Tier 3 fleet 
average standards. In effect reducing sulfur from

[[Page 23474]]

30 ppm to 10 ppm has such a large impact on the ability of the 
technology improvements to achieve Tier 3 emissions levels that absent 
these sulfur reductions there is not a suite of technology advancements 
available to fill the resulting gap in emissions reductions. We cannot 
identify a technology path for vehicles that would achieve the Tier 3 
Bin 30 average standard, across the fleet, with sulfur at 30 ppm 
levels, and as a result Tier 3 levels would not be technically feasible 
and achievable.
    This analysis also applies to gasoline sulfur levels between 10 and 
30 ppm, e.g., 20 ppm. The Tier 3 required emissions reductions are so 
large and widespread across the fleet, and the technology challenges 
are sufficiently high, especially for heavier vehicles, that the large 
increase in emissions that would occur from a higher average sulfur 
level compared to a 10 ppm average would lead to an inability for 
vehicle technologies to widely achieve Tier 3 levels as a fleet wide 
average in order to meet the Bin 30 fleet average standard.
    EPA acknowledges that some models in the light-duty fleet, when 
viewed in isolation, may be able to achieve Tier 3 levels at current 
sulfur levels of 30 ppm average. Under the Tier 3 fleet average 
standards, it is not sufficient for one or a few of a manufacturer's 
vehicle models to meet Tier 3 levels because the manufacturer's light-
duty vehicle fleet as a whole must achieve the Tier 3 30 mg/mi exhaust 
emissions standard as a fleet-wide average. As discussed above, all 
vehicle models will need to achieve further reductions and be either 
below or no more than somewhat above Tier 3 levels to achieve the Tier 
3 standard as a fleet wide average. Absent the reductions in sulfur 
levels to 10 ppm average, this is not achievable from a technology 
perspective.
    As discussed in Section V.B, the average 10 ppm gasoline sulfur 
standard is feasible and is the level that appropriately balances costs 
with the emission reductions that it provides and enables. Not only 
will a 10 ppm sulfur standard enable vehicle manufacturers to certify 
their entire product line of vehicles to the Tier 3 fleet average 
standards, but reducing gasoline sulfur to 10 ppm will better enable 
these vehicles to maintain their emission performance in-use over their 
full useful life. Higher sulfur levels would make it impossible for 
vehicle manufacturers to meet the Tier 3 standards, and would forego 
the very large immediate reductions from the existing fleet. Reducing 
the sulfur level below 10 ppm would further reduce vehicle emissions 
and allow the Tier 3 vehicle standards to be achieved more easily. 
However, we believe that a 10 ppm average standard is sufficient to 
allow vehicles to meet the Tier 3 standards. Further, as discussed in 
Sections V.B and IX.B there are significant challenges associated with 
reducing sulfur below 10 ppm.
7. Other Provisions
a. Early Credits
    The California LEV III program is scheduled to begin at least two 
model years earlier than the federal Tier 3 program.\322\ The Tier 3 
standards begin in MY 2017 for vehicles 6,000 lbs GVWR and less, and in 
MY 2018 for vehicles over 6,000 lbs GVWR. As a result, LEV III vehicles 
sold in California beginning in MY 2015 will be required to meet a 
lower fleet average NMOG+NOX level than the federal fleet 
will be meeting at that time. In addition, the California 
NMOG+NOX standards will further decline before Tier 3 
begins, resulting in the gap growing between the current federal 
program and LEV III.
---------------------------------------------------------------------------

    \322\ See California Low-Emission Vehicles (LEV) & GHG 2012 
regulations adopted by the State of California Air Resources Board, 
March 22, 2012, Resolution 12-21 incorporating by reference 
Resolution 12-11, which was adopted January 26, 2012. Available at 
http://www.arb.ca.gov/regact/2012/leviiighg2012/leviiighg2012.htm 
(last accessed December 2, 2013).
---------------------------------------------------------------------------

    We are finalizing an early credit program that with minor revisions 
is as we proposed. We have designed the early credit provisions to 
accomplish three goals: (1) To encourage manufacturers to produce a 
cleaner federal fleet earlier than otherwise required; (2) to provide 
valuable flexibility to the manufacturers to facilitate the significant 
``step down'' from the current Tier 2 Bin 5 fleet average required in 
MY 2016 to the LEV III-based declining fleet average in MY 2017; and 
(3) to create an overall Tier 3 program that although starts later, is 
equivalent in stringency to the LEV III program such that manufacturers 
will be able to produce a 50-state fleet at the earliest opportunity. 
Commenters were generally supportive of or silent on the early credits 
program as proposed.
    The early credit program we are finalizing includes several 
distinct provisions. The first provision allows manufacturers to 
generate early federal credits against the current Tier 2 Bin 5 
requirement \323\ in MYs 2015 and 2016 for vehicles under 6,000 lbs 
GVWR and MYs 2016 and 2017 for vehicles greater than 6,000 lbs GVWR. 
Early credits will only be available to manufacturers that comply under 
the primary program (declining fleet average), not the alternative 
phase-in approach (Section IV.A.2.c above). In order to generate these 
credits, manufacturers sum the bin specific NMOG and NOX 
certification standards for each federally certified Tier 2 vehicle and 
the bin NMOG+NOX standards for any vehicle certified under 
the Early Tier 3 provision described below and calculate an 
NMOG+NOX fleet average for the entire manufacturers fleet 
sold in a model year. Credits are based on how far the fleet average is 
below the existing Tier 2 Bin 5 requirement (160 mg/mi total of NMOG 
and NOX). We expect that manufacturers will be able to 
achieve a fleetwide average below the Tier 2 Bin 5 level by several 
means, such as certifying LEV III vehicles either under Tier 2 or as 
Early Tier 3 vehicles under Tier 3 (discussed in the next section) to 
bin levels lower than Tier 2 Bin 5. Our analysis, presented in Section 
IV.A.5 above and Chapter 1 of the RIA, shows that manufacturers could 
certify many vehicles currently certified to Tier 2 Bin 5 to a lower 
bin--e.g., to Tier 2 Bin 3 or Bin 4--by simply accepting a relatively 
small reduction in compliance margins. Many manufacturers certify Tier 
2 vehicles to Tier 2 Bin 5 but also certify the same vehicle to a 
cleaner emission standard under the LEV II program (e.g. ULEV) with 
only a compliance margin difference.
---------------------------------------------------------------------------

    \323\ Tier 2 standards are not set in the form of 
NMOG+NOX. The equivalent Tier 2 Bin 5 fleet average in 
NMOG+NOX terms is equal to 160 mg/mi (90 mg/mi NMOG + 70 
mg/mi NOX).
---------------------------------------------------------------------------

    We believe that the early credit provision will help us realize 
both our first and second goals presented above. For example, a 
manufacturer certifying their federal fleet to Tier 2 Bin 4 will earn 
50 mg/mi of NMOG+NOX credits per vehicle (i.e., 160 mg/mi 
minus 110 mg/mi), which we believe will encourage manufacturers to 
certify a cleaner federal fleet and provide a reasonable opportunity 
for credit generation to facilitate the ``step down'' in stringency.
    At the same time, if we allowed manufacturers to generate excessive 
early credits, manufacturers might thereby delay their compliance with 
the Tier 3 program, and thus the harmonization with LEV III, for 
several years. This would be in direct conflict with our third goal of 
creating a program of equal stringency to the California program as 
early as possible. In order to address this concern, we proposed and 
are finalizing a provision limiting the application of the early Tier 3 
credits to the following conditions:
     Early Tier 3 credits generated as described above could be 
used without limitation in MY 2017 on the portion of

[[Page 23475]]

the fleet entering the Tier 3 program in that MY.
     Credits used for compliance in MY 2018 and beyond will be 
capped at an amount equal to the lesser of the manufacturer's federal 
credits as calculated above or the manufacturer's LEV III credits 
scaled up by the ratio of 50-state sales to California and LEV III 
required states sales. This limitation accounts for the fact that some 
LEV III credits may have begun to expire and will no longer be eligible 
as a basis for Tier 3 early credits.
    By capping the available federal Tier 3 early credits, we believe 
that the two programs, LEV III and Tier 3 will be at parity in terms of 
relative stringency starting in MY 2018. In addition, because the 
number of Tier 3 early credits that can be used is based on the number 
of LEV III credits that the manufacturer has generated, there may be 
additional motivation for manufacturers to over-perform in California 
during the initial model years, accelerating emission reduction 
benefits.
    Finally, we are adopting, as proposed, a limitation on the life of 
Tier 3 early credits to 5 years, with no discounting, consistent with 
the California LEV III program.
b. Early Tier 3 Compliance
    We are finalizing, as proposed, the requirement that manufacturers 
begin the Tier 3 program in MY 2017 for vehicles up to 6,000 lbs GVWR 
and MY 2018 for vehicles above 6,000 lbs GVWR under the primary phase-
in. The only proposed compliance approach available prior to MY 2017 
was for manufacturers to continue to certify vehicles to the existing 
Tier 2 standards with the opportunity to earn early credits (see 
previous section) that could be used in MY 2017 and later.
    Several auto industry commenters suggested additional provisions 
that could facilitate earlier harmonization between Tier 3 and LEV III 
and streamlining of development and certification of vehicle models. 
Specifically, these commenters requested the ability to have vehicles 
certified to the Tier 3 standards in MYs 2015 and 2016. They commented 
that this would allow them to develop, certify and sell a vehicle model 
for all 50 states, reducing the complexity of potentially different 
federal and California requirements in MYs 2015 and 2016. Additionally, 
commenters noted that the Tier 3 program provides more flexibility in 
the certification bin structure compared with the existing Tier 2, 
providing them additional opportunities to generate early credits.
    To address this concern, we are finalizing a provision to allow 
manufacturers to certify to Tier 3 standards starting in MY 2015 as 
``Early Tier 3'' vehicles. Manufacturers will have the option to 
certify their vehicle models to meet the Tier 3 emission requirements 
in MY 2015 and 2016 for all LDVs, LDTs, and MDPVs, which would have 
been required to begin in MY 2017 under the primary program. As an 
example, a manufacturer choosing to certify a vehicle as Early Tier 3 
can bring the same vehicle models certified to LEV III standards \324\ 
in MY 2015 or 2016 into the Early Tier 3 program by meeting all the 
same requirements under the primary Tier 3 schedule. There would not be 
a Tier 3 fleet average requirement for FTP or SFTP in MY 2015 or 2016 
(and 2017 for vehicles over 6,000 lbs GVWR and up to 8,500 and MDPVs) 
if all the same vehicle models certified to LEV III are also certified 
as the Early Tier 3 vehicles meeting the same LEV III emission 
standards and also the Tier 3 additional requirements (high altitude, 
and cold CO and hydrocarbons). These Early Tier 3 vehicles would 
replace any Tier 2 offering of the vehicle model consistent with the 
LEV III offering replacing the LEV II models. If a manufacturer chooses 
to certify only a portion of their LEV III vehicle models as Early Tier 
3 vehicles in a given MY, they will be required to meet the LEV III 
fleet average requirements in that MY for those models certified as 
Early Tier 3 vehicles. All vehicles models not certified as Early Tier 
3 vehicles must meet all Tier 2 requirements.
---------------------------------------------------------------------------

    \324\ Including LEV III SFTP requirements.
---------------------------------------------------------------------------

c. Useful Life
    The ``useful life'' of a vehicle is the period of time, in terms of 
years and miles, during which a manufacturer is responsible for the 
vehicle's emissions performance. For the Tier 3 program, we are 
finalizing several changes to the existing useful life provisions that 
are appropriate to the new Tier 3 standards described above.
    The auto manufacturing industry has uniformly expressed the desire 
to produce and sell a single national vehicle fleet, including a 
general ability and willingness of the industry to certify their 
vehicles to a 150,000 mile, 15 year full useful life, as required by 
the LEV III program. However, the CAA, written at a time when vehicles 
did not last as long as they do today, precludes EPA from requiring a 
useful life value longer than 120,000 miles (and 10 or 11 years, 
depending on vehicle category and weight) for lighter light-duty 
vehicles (LDVs and LDTs up to 3,750 lbs loaded vehicle weight (LVW) and 
up to 6,000 lbs GVWR (i.e., LDT1s)).
    For heavier light-duty vehicles (i.e., LDT2s, 3s, 4s, as well as 
MDPVs, representing a large fraction of the light-duty fleet), this 
statutory restriction does not apply, and we are finalizing a 150,000 
mile, 15 year useful life value, as proposed. For the lighter vehicles, 
we are continuing to apply the 120,000 mile (and 10 or 11 year, as 
applicable) useful life requirement from the Tier 2 program, also as 
proposed. For these lighter vehicles, manufacturers are allowed to 
choose to certify to either useful life value in complying with the 
fleet average.\325\ In order for the Tier 3 NMOG+NOX 
standards to represent the same level of stringency regardless of which 
useful life value manufacturers choose, we proposed and are finalizing 
proportionally lower numerical values (85 percent of the 
NMOG+NOX 150,000 mile standards based on a data analysis in 
Chapter 1 of the RIA) for the declining fleet average FTP 
NMOG+NOX standards when a manufacturer chooses the 120,000 
mile useful life. A manufacturer choosing the 120,000 mile useful life 
for any vehicle must maintain separate 120,000 mile and 150,000 mile 
useful life fleet averages for purposes of FTP NMOG+NOX 
fleet average compliance. Credits generated towards the required fleet 
averages are not transferable between the two useful life fleet 
averages.
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    \325\ CARB has stated that they do not expect to accept vehicles 
certified under the federal Tier 3 program to a 120,000 mile useful 
life value for California certification, and thus for meeting 
California's fleet average NMOG+NOX standards.
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    We proposed that a manufacturer that certifies any vehicle model 
under the 120,000 mile provision be required to certify all their LDVs 
and LDT1s to the 120,000 mile useful life and associated numerically 
lower FTP NMOG+NOX fleet average standard. Comments from the 
auto industry expressed a concern that this approach would be 
inflexible to manufacturers' needs and unnecessarily burdensome. We 
have considered these comments, and we believe that the emission 
benefits of Tier 3 program will not be adversely affected if 
manufacturers are allowed to certify these lighter vehicles to the 
120,000 mile useful life standards on a test group basis, and therefore 
we are finalizing this approach. Standards for all other pollutants 
\326\ and all other test cycles such as SFTP remain the same regardless 
of whether manufacturers

[[Page 23476]]

choose the 120,000 mile or the 150,000 mile useful life periods.
---------------------------------------------------------------------------

    \326\ PM, CO, and HCHO.
---------------------------------------------------------------------------

    For emission standards other than PM standards (e.g., 
NMOG+NOX standards), as proposed, manufacturers will be 
required to certify all vehicles to the 150,000 mile useful life 
beginning with the first model year that a vehicle model is certified 
to the FTP NMOG+NOX Bin 70 or lower (other than vehicles not 
yet required to meet a 150,000 mile useful life during the program 
phase in, and vehicles for which a manufacturer has the option and 
chooses to apply the 120,000 mile useful life value). This useful life 
requirement will apply as early as MY 2017. Beginning in MY 2020, all 
vehicles will need to certify to the 150,000 mile useful life for all 
emissions, regardless of NMOG+NOX certification bin, unless 
they are eligible for, and the manufacturer has chosen the 120,000 mile 
useful life and associated standards. (Note that the timing of the 
requirement to certify on the new test fuel follows the same approach 
as for the useful life requirement for emission standards other than PM 
standards (i.e., based on the first year a model is certified to FTP 
NMOG+NOX Bin 70 or below) as described in the next section.) 
For FTP and SFTP PM useful life requirements, manufacturers will be 
required to certify to 150,000 mile useful life for PM all vehicles 
that are included in the manufacturer's phase-in percentage meeting the 
new PM standards (other than eligible vehicles for which a manufacturer 
chooses to apply the 120,000 miles useful life value).
d. Test Fuels for Exhaust Criteria Emissions Standards
    We recognize that test fuels are an important element of a national 
program. Vehicle manufacturers have emphasized in their comments the 
desire to reduce their test burdens by producing one vehicle that is 
tested on a single test procedure and on a single test fuel and that 
meets both California and federal requirements. Although we have been 
able to reasonably align the Tier 3 program with the LEV III program in 
most key respects, we recognize that the Tier 3 and LEV III test fuels 
are different, and that there may still exist some differences in 
emissions performance between vehicles tested on the two fuels. The 
largest difference between the two fuels is the Reid Vapor Pressure 
(RVP), and other differences in distillation properties and aromatic 
levels also exist (largely related to differences in actual in-use fuel 
nationally and in California). We are finalizing as proposed the 
requirement that manufacturers certify vehicles on the new Tier 3 E10 
test fuels \327\ beginning with the first model year that a vehicle 
model is certified to the FTP NMOG+NOX Bin 70 or lower.\328\ 
This requirement may apply as early as MY 2017 for vehicles up to 6000 
lbs GVWR and MY 2018 for vehicles greater than 6000 lbs GVWR.\329\ This 
requirement also applies to vehicles certified at Bin 70 and lower that 
are brought into the Tier 3 program under the Early Tier 3 option 
described in IV.A.7.b above, with the exception of the specific 
provision allowing the use of LEV III fuels discussed below. Beginning 
in MY 2020, all gasoline-fueled models will need to certify on the Tier 
3 test fuels for all exhaust emission requirements, regardless of their 
certification bin.\330\ As discussed in Section IV.A.7.c above, 
manufacturers must also meet the 150,000 mile useful life requirements 
for NMOG+NOX standards for these same vehicles as they are 
certified to Bin 70 and lower.
---------------------------------------------------------------------------

    \327\ This includes fuels used for cold temperature and high 
altitude testing and durability requirements. See Section IV.F 
below.
    \328\ The lower Bins are Bin 0, Bin 20, Bin 30 and Bin 50.
    \329\ Vehicles above 6000 lb GVWR choosing the alternative 
phase-in schedules described in Section IV.A.2.c above generally 
would begin using the Tier 3 test fuels for MY2019.
    \330\ Diesel fueled and alternative fueled vehicles will 
continue to test on the fuels used under the Tier 2 program except 
for E85 fueled vehicles, for which we are finalizing new test fuel 
specifications (see Section IV.F below).
---------------------------------------------------------------------------

    During the transition period from Tier 2 fuel to the new Tier 3 and 
LEV III E10 fuels, manufacturers have indicated that they face a 
substantial workload challenge of developing and certifying each 
vehicle model to the two new fuels simultaneously. We recognize this 
transitional challenge and are including an additional option. We are 
finalizing as proposed an option that vehicles certified in MYs 2015 
through 2019 to California LEV III standards using California LEV III 
E10 certification test fuels and test procedures can be used for 
certifying to EPA Tier 2 or Tier 3 exhaust emission standards, 
including PM. A manufacturer may submit LEV III test data on vehicles 
tested using the new LEV III E10 fuels for Tier 2 or Tier 3 
certifications. Consistent with existing Tier 2 policy, EPA may test 
vehicles certified to Tier 2 standards using LEV III test results on 
Tier 2 fuel for confirmatory or in-use exhaust testing. For vehicles 
certified in MY 2017 through 2019 to Tier 3 standards using LEV III E10 
fuels, EPA will only use LEV III E10 fuels for confirmatory and in-use 
testing (except for high altitude or cold CO and hydrocarbons testing, 
as described below). Vehicles certified to the provisions of Early Tier 
3 (Section IV.A.7.b above) will be treated the same as Tier 3 vehicles 
certified in MY 2017. For example, for MY 2015 and 2016, EPA will 
consider Early Tier 3 vehicles to be part of the Tier 3 program for 
purposes of fuel-related testing obligations. We will not accept test 
results using LEV II fuels for Tier 3 vehicle certification, including 
Early Tier 3 certifications, with the exception of the PZEV exhaust 
carry-over provision described below.
    California does not have fuel specifications for high altitude 
testing or cold CO and hydrocarbon testing. For this reason, we are 
finalizing that for vehicles that manufacturers choose to certify using 
LEV III fuel and test procedures, manufacturers must use program-
specific federal test fuels to comply with these federal-only 
requirements (i.e. Tier 2 vehicles will use Tier 2 fuel and Tier 3 
vehicles will use Tier 3 fuel). Similarly, high altitude and cold CO 
and hydrocarbon confirmatory and in-use testing for these vehicles will 
be performed on the federal fuel that the manufacturer is required to 
use at certification as specified above regardless of whether LEV III 
or federal fuel is used for other testing.
    We proposed the requirement that after MY 2019, all Tier 3 
certification, confirmatory and in-use emission testing be required to 
use only the proposed Tier 3 E15 test fuel because it was believed to 
be a worst case fuel for emissions. Because we are finalizing Tier 3 
E10 test fuels which are very similar as explained above to LEV III E10 
test fuels, and not considered a worst case fuel, we are not finalizing 
the requirement for all testing to be performed on Tier 3 E10 test 
fuel. Instead, for certifications after MY 2019, EPA will continue to 
allow LEV III test results to be submitted for certification to Tier 3 
standards, consistent with protocol under the Tier 2 program. However, 
if a manufacturer chooses to submit certification results for 
compliance with Tier 3 standards using the LEV III test fuel, then for 
confirmatory and in-use testing we will hold vehicles to the Tier 3 
standards while using the Tier 3 fuel in addition to the LEV III test 
fuel; we will not allow new or carry-over certifications using LEV II 
or Tier 2 certification test fuels after MY 2019. CARB has indicated 
that they will accept Tier 3 test data (on federal certification test 
fuels) to obtain a California certificate as early as MY 2015. In this 
manner manufacturers should be able to avoid compliance testing on more 
than one fuel, since vehicles certified to Interim or Final

[[Page 23477]]

Tier 3 status using federal certification test fuels could also obtain 
LEV III certification.
    Auto industry commenters noted that the LEV III program provides an 
allowance for manufacturers to carry over PZEV-certified vehicle 
exhaust data \331\ from the LEV II program into LEV III compliance in 
MY 2015 through MY 2019. Thus, CARB allows these PZEV vehicles to use 
emission testing results using LEV II fuel (i.e. California Phase II 
test fuel) to meet the LEV III obligations. The commenters suggested 
that EPA allow manufacturers to carry over such PZEV 150,000 mile 
useful life exhaust emission data to meet the Tier 3 standards. We 
agree that this approach is appropriate during the transition, and we 
are finalizing this provision for MY 2015 through MY 2019, including 
allowing Early Tier 3 compliance at the Bin 30 level as a combined 
NMOG+NOX standard. EPA will hold vehicles certified using 
this provision to the Tier 3 emission requirements when they are tested 
on the LEV II fuel for confirmatory and in-use. Compliance testing of 
these vehicles for all other Tier 3 obligations (i.e., high-altitude 
testing and Cold CO and hydrocarbons testing) must be performed using 
Tier 3 fuel, and these vehicles will be required to meet the Tier 3 
standards for Bin 30.
---------------------------------------------------------------------------

    \331\ California's PZEV exhaust standards are the same as their 
SULEV standards and the Tier 3 Bin 30, and are certified to a 
150,000 mile useful life.
---------------------------------------------------------------------------

e. High Altitude Requirements
    FTP emission standards are historically designed to be applicable 
at all altitudes. Under Tier 2, the same FTP emission bin standards 
applied to vehicles tested at both low and high-altitude. However, 
fundamental physical challenges exist at high altitude resulting in 
typically higher emissions during cold starts compared with starts at 
lower altitudes (i.e., sea level), and these challenges become more 
pronounced as emission standards become more stringent. This expected 
increase in emissions is primarily due to the lower air density at 
higher altitudes. Due to the lower air density, the needed volume of 
the hot combustion exhaust required to quickly heat the catalyst in the 
first minute after a cold start is reduced. As a result, catalyst 
light-off is delayed and cold start emissions can increase. Vehicles 
under the Tier 2 program typically have had sufficient compliance 
margins to absorb this increase in emissions during testing under high-
altitude conditions. However, given the extremely low standards we are 
finalizing in Tier 3, manufacturers will have less compliance margin 
with which to address the issue.
    Under the Tier 3 program, we expect that the emission control 
technologies selected for low altitude performance will also provide 
very significant emission control at high altitude.\332\ However, as 
explained above, unique emission challenges exist with operation at 
higher altitude, often requiring manufacturers to design their emission 
controls specifically for higher altitude.
---------------------------------------------------------------------------

    \332\ High-altitude conditions means a test altitude of 1,620 
meters (5,315 feet). Low altitude conditions means a test altitude 
less than 549 meters (1,800 feet).
---------------------------------------------------------------------------

    We do not believe that the impact of the fairly small fraction of 
overall U.S. driving that occurs in high altitude locations warrants a 
requirement for additional technologies to be applied specifically for 
high-altitude conditions. To avoid requiring manufacturers to use 
special high-altitude emission control technologies, we are allowing 
manufacturers limited relief for certification testing at high 
altitude, as proposed. Specifically, for sea-level certifications to 
Tier 3 Bins 20, 30, and 50, a manufacturer could comply with the next 
less-stringent bin for testing at high altitude. For example, a 
manufacturer can certify to Bin 50 for testing at high altitude versus 
Bin 30 at sea level). For vehicles certified at sea level to Bins 70 
and 125, manufacturers can comply with standards 35 mg/mi higher (e.g., 
105 mg/mi and 160 mg/mi, respectively. We are providing no high 
altitude relief for vehicles certified to Bin 160. This high altitude 
relief provision applies to all Final Tier 3 vehicles for the duration 
of the Tier 3 program.
    For intermediate altitudes that fall between the specified low and 
high altitude test conditions, the emission performance should continue 
to be representative of the controls implemented to meet standards at 
the required altitude test conditions, consistent with Tier 2 protocol. 
Any deviation in the use of these controls at the intermediate 
altitudes may be considered an AECD that must be reported by the 
manufacturer and justified as not being a defeat device.\333\
---------------------------------------------------------------------------

    \333\ Sec.  86.1809-12 Prohibition of defeat devices
---------------------------------------------------------------------------

    Table IV-9 presents the Tier 3 high altitude standards.

               Table IV-9--Tier 3 High Altitude Standards
------------------------------------------------------------------------
                                           Sea level FTP   Altitude FTP
                   Bin                     standard (mg/   standard (mg/
                                           mi NMOG+NOX)    mi NMOG+NOX)
------------------------------------------------------------------------
Bin 160.................................             160             160
Bin 125.................................             125             160
Bin 70..................................              70             105
Bin 50..................................              50              70
Bin 30..................................              30              50
Bin 20..................................              20              30
------------------------------------------------------------------------

f. Highway Test Standards
    Sustained high-speed operation can result in NOX 
emissions that may not be represented on either the FTP or SFTP cycles. 
Although we are not aware of any serious issues with this mode of 
operation with current Tier 2 vehicles, we are interested in preventing 
increases in these NOX emissions as manufacturers develop 
new or improved engine and emission control technologies.
    For this reason, we are finalizing, as proposed, a provision that 
the Tier 3 FTP NMOG+NOX standards above also apply on the 
Highway Fuel Economy Test (HFET), which is performed as a part of GHG 
and Fuel Economy compliance testing. Thus, the Tier 3 FTP 
NMOG+NOX standard for the bin at which a manufacturer has 
chosen to certify a vehicle will also apply on the HFET test. For 
example, if a manufacturer certifies a vehicle to Bin 70, the vehicle's 
NMOG+NOX performance over the HFET could not exceed 70 mg/
mi. Manufacturers will simply need to ensure that the same emission 
control strategies implemented for the FTP and SFTP cycles are also 
effective during the highway test cycle. We believe that this 
requirement will not require manufacturers to take any unique 
technological action, will not add technology costs, and will not add 
significantly to the certification burden.
g. Interim 4,000 Mile SFTP Standards
    During the period of the declining NMOG+NOX standards, 
we are finalizing the proposed requirement that interim Tier 3 vehicles 
meet 4,000 mile SFTP standards, consistent with the existing Tier 2 and 
LEV II program requirements. The 4,000 mile standards apply to each 
vehicle model individually and to each component of the SFTP composite 
cycle. This approach is designed to prevent excessive emission levels 
from individual vehicle models being masked by the averaging of the 
manufacturer's fleet emissions. Similarly, this approach also prevents 
poor performance on a

[[Page 23478]]

single cycle of the SFTP. We believe it is appropriate to require any 
individual Interim Tier 3 vehicle to at a minimum meet the existing 
requirements under the Tier 2 and LEV II programs. Table IV-10 below 
presents the 4,000 mile SFTP standards for interim Tier 3 vehicles.

                   Table IV-10--4,000 Mile SFTP Exhaust Standards for Interim Tier 3 Vehicles
                                                  [grams/mile]
----------------------------------------------------------------------------------------------------------------
                Vehicle category                   US06 NMOG+NOX      US06 CO      SC03 NMOG+NOX      SC03 CO
----------------------------------------------------------------------------------------------------------------
LDV/LDT1........................................            0.14             8.0            0.20             2.7
LDT2............................................            0.25            10.5            0.27             3.5
LDT3............................................            0.4             10.5            0.31             3.5
LDT4............................................            0.6             11.8            0.44             4.0
----------------------------------------------------------------------------------------------------------------

    We believe that vehicles considered to be Final Tier 3 vehicles 
(i.e., they meet the Tier 3 PM requirements, specifically the stringent 
SFTP PM standards) will have sufficiently robust designs that the 4,000 
mile SFTP standards will no longer be necessary and so will not apply 
to those vehicles. Additionally, once the program reaches the fully 
phased-in fleet average composite standard of 50 mg/mi in 2025, high 
SFTP emissions even on a limited portion of a manufacturer's fleet 
should be effectively mitigated, and the 4,000 mile SFTP standards will 
no longer apply.
h. Phase-In Schedule
    As proposed, the major provisions of the Tier 3 program phase in 
based on model year and on the emission levels to which manufacturers 
certify their vehicles. As described in Section IV.A.3, under the Tier 
3 program, manufacturers are required to certify each vehicle model to 
an FTP bin, which is then used to calculate the NMOG+NOX 
fleet average of all of its Tier 3 vehicles. Manufacturers must also 
determine the SFTP levels of each model and calculate the 
NMOG+NOX fleet average for the SFTP requirements as 
described in Section IV.A.4. These separate FTP and SFTP fleet average 
calculations satisfy one aspect of certification under the Tier 3 
program, specifically the standards associated with each model year.
    As described in Sections IV.A.7.c and IV.A.7.d above, the longer 
(150,000 mile) useful life value, as applicable, and the new Tier 3 
test fuel for exhaust testing will be implemented as manufacturers 
certify vehicles to more stringent NMOG+NOX standards, with 
the threshold to implement both of these provisions being Bin 70. 
Beginning in MY 2017, any vehicle certified to Bin 70 or lower will be 
required to be certified on Tier 3 test fuel. In addition, any vehicle 
certified to Bin 70 or lower that is required to meet the longer 
150,000 mile useful life will be required to do so at that point. 
Independent of the Tier 3 test fuel phase in schedule, the 150,000 mile 
useful life for PM standards will be required when the vehicle is 
certified to the new Tier 3 PM standards as described below in the PM 
phase-in schedules. Beginning in MY 2020, all gasoline-fueled vehicles 
will be required to be certified for exhaust emissions on the Tier 3 
test fuel, regardless of their certification bin or applicable useful 
life.
    Manufacturers must also comply with more stringent PM standards on 
a percent phase-in schedule. Compliance with the PM standards, which is 
consistent with the CARB LEV III program, is independent of the 
NMOG+NOX fleet average requirements described above. The PM 
emission standards for FTP and SFTP described in Section IV.A.3 and 4 
respectively will be implemented as a percent phase-in requirement as 
described below under a primary phase-in schedule or under an optional 
phase-in schedule.
    Vehicle models that a manufacturer certifies to a Tier 3 
NMOG+NOX bin, that meet the requirements of the PM phase-in 
schedule, and that comply with the other Tier 3 requirements (i.e., 
150,000 mile useful life and Tier 3 test fuel, as applicable) will be 
considered ``Final Tier 3'' compliant vehicles. All other vehicles 
certified to Tier 3 bins but not yet meeting the PM and other Tier 3 
requirements will be considered ``Interim Tier 3'' compliant vehicles. 
At the completion of the percent phase-in period for PM (2021 for the 
primary PM phase-in schedule and 2022 for the optional PM phase-in 
schedule, as described below), 100 percent of vehicles will need to 
meet all of the Tier 3 requirements and will be considered Final Tier 3 
vehicles.
    As proposed, for the PM requirements, each model year manufacturers 
must meet either the primary PM percent phase-in or the optional PM 
phase-in as described in the following subsections. The primary percent 
PM phase-in schedule is composed of fixed annual minimum phase-in 
percentages that we expect most manufacturers to choose in order to 
comply with the Tier 3 requirements. The optional PM phase-in schedule 
provides additional flexibility for manufacturers with too few product 
offerings to allow for a sufficiently gradual transition into the Final 
Tier 3 requirements, as described below. In either case, Interim Tier 3 
vehicles not yet meeting the Tier 3 PM standards must at a minimum meet 
the Tier 2 PM full useful life FTP PM standard of 10 mg/mi and the SFTP 
PM weighted composite standard of 70 mg/mi.
i. Primary PM Percent Phase-In Schedule
    It is important to note that the percent phase-in of the new Tier 3 
PM standards and the declining fleet average NMOG+NOX 
standards that we are finalizing are separate and independent elements 
of the Tier 3 program. ``Phase-in'' in the context of Tier 3 PM 
standards means the fraction of a manufacturer's fleet that is required 
to meet the new Tier 3 PM standards in a given model year. We expect 
that manufacturer fleets may consist of a mix of vehicle models 
certified to Tier 2, LEV II, LEV III and Tier 3 standards throughout 
the percent phase-in period.
    As discussed above, vehicles originally certified to Tier 2, LEV 
II, and LEV III may be carried over into the Tier 3 program as Interim 
Tier 3 vehicles. A vehicle will be considered a Final Tier 3 vehicle 
when it is certified to one of the Tier 3 bins, meets the new Tier 3 PM 
standards for FTP (3mg/mi) and US06 (10 or 6 mg/mi), certifies to the 
150,000 useful life value (as applicable), and certifies on the new 
Tier 3 test fuel. Table IV-11 below presents the PM phase-in schedule 
for Final Tier 3 vehicles.

[[Page 23479]]



                                               Table IV-11--PM Phase-In Schedule for Final Tier 3 Vehicles
--------------------------------------------------------------------------------------------------------------------------------------------------------
             Model year                              2017                      2018            2019            2020            2021       2022 and later
--------------------------------------------------------------------------------------------------------------------------------------------------------
Manufacturer's Fleet (%)............  20 a..............................              20              40              70             100             100
                                                                         -------------------------------------------------------------------------------
Vehicle Types.......................  <= 6,000 lbs GVWR.................                     All vehicles <= 8,500 lbs GVWR and MDPVs
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Manufacturers comply in MY 2017 with 20 percent of their LDV and LDT fleet under 6,000 lbs GVWR, or alternatively with 10 percent of their total
  LDV, LDT, and MDPV fleet Optional PM Phase-in

    The PM percent-of-sales phase-in schedule described above will 
allow manufacturers with multiple vehicle models to plan the phase-in 
of those models based on anticipated volumes of each vehicle model. 
However, manufacturers certifying only a few vehicle models might not 
benefit from this schedule. This is because, in order to satisfy the 
phase-in schedule percentages, they may have to over-comply with the 
required percentages earlier than will a manufacturer with many vehicle 
models available for the phase-in.
    For instance, a manufacturer with only two models that each equally 
account for 50 percent of their sales will be required to introduce (at 
least) one of the models in MY 2017 to meet the PM phase-in requirement 
of 20 percent in the first year. Because it represents 50 percent of 
the manufacturer's sales, this model will then also meet the 
requirements for MY 2018 (20 percent) and MY 2019 (40 percent). To meet 
the MY 2020 requirement of 70 percent of sales, however, the 
manufacturer will need to introduce the second Tier 3 vehicle that 
year. Thus the manufacturer will have introduced 100 percent of its 
Tier 3 models one year earlier than required of a manufacturer that is 
able to delay the final 30 percent of its fleet until MY 2021 (by 
distributing its models over the entire phase-in period).
    To provide for more equivalent phasing in of the PM requirements 
among all manufacturers in the early years of the program, we are 
finalizing, as proposed, an optional ``indexed'' PM phase-in schedule 
that can be used by a manufacturer to meet its PM percent phase-in 
requirements. A manufacturer that exceeds the phase-in requirements in 
any given year will be allowed to, in effect, offset some of the phase-
in requirements in a later model year. The optional phase-in schedule 
will be acceptable if it passes a mathematical test. The mathematical 
test is designed to provide manufacturers a benefit from certifying to 
the standards at higher volumes than they are obligated to under the 
normal phase-in schedule, while ensuring that significant numbers of 
vehicles are meeting the new Tier 3 requirements during each year of 
the optional phase-in schedule. In this approach, manufacturers weight 
the earlier years by multiplying their percent phase-in by the number 
of years prior to MY 2022 (i.e., the second year of the 100 percent 
phase-in requirement).
    The mathematical equation for applying the optional PM phase-in is 
as follows: (5 x APP2017) + (4 x APP2018) + (3 x APP2019) + (2 x 
APP2020) + (1 x APP2021) = 540, where APP is the actual phase-in 
percentage for the referenced model year.
    The sum of the calculation must be greater than or equal to 540, 
which is the result when the optional phase-in equation is applied to 
the primary percent phase-in schedule (i.e., 5 x 20% + 4 x 20% + 3 x 
40% + 2 x 70% + 1 x 100% = 540).
    Applying the optional PM phase-in equation to the hypothetical 
manufacturer in the example above, the manufacturer can postpone its 
model introductions by one year each, to MY 2018 and MY 2021. Its 
calculation is (5 x 0% + 4 x 50% + 3 x 50% + 2 x 50% + 1 x 100% = 550, 
and thus the phase-in is acceptable.
i. In-Use Standards
i. NMOG+NOX
    The Tier 3 emission standards will require a substantial migration 
of emission control technology historically used only on a small 
percent of the fleet and typically limited to smaller vehicles and 
engines. While we believe that these technologies can generally be used 
on any vehicle and are applicable to the entire fleet, manufacturers 
have less experience with the in-use performance of these technologies 
across the fleet. For example, technologies that accelerate catalyst 
warm-up such as catalyst location close to the engine exhaust ports and 
other advanced thermal management approaches will be new to certain 
vehicle types, particularly larger vehicles (i.e., LDT3/4s), which have 
historically not relied on these technologies to meet emission 
standards.
    As proposed, to help manufacturers address the lack of in-use 
experience and associated challenges with the expanded introduction of 
these technologies, particularly in the larger vehicles, we are 
finalizing temporarily-relaxed in-use NMOG+NOX standards 
that will apply to all vehicles certified to Bins 70 and cleaner as 
Interim or Final Tier 3 vehicles. The in-use standards will apply 
during the entire percent phase-in period (i.e., through MY 2021). The 
in-use standards are 40 percent less stringent than the certification 
standards, providing a significant but reasonable temporary cushion for 
the uncertainties associated with new technologies (or new applications 
of existing technologies) over the life of the vehicles.
    The in-use NMOG+NOX standards are shown in Table IV-12.

   Table IV-12--FTP In-Use Standards for Light Duty Vehicles and MDPVs
                                 [mg/mi]
------------------------------------------------------------------------
                                                           NMOG+NOX (mg/
                           Bin                                  mi)
------------------------------------------------------------------------
Bin 160.................................................             160
Bin 125.................................................             125
Bin 70..................................................              98
Bin 50..................................................              70
Bin 30..................................................              42
Bin 20..................................................              28
------------------------------------------------------------------------

ii. PM
    As with the NMOG+NOX standards, the introduction of new 
emission control technologies or new applications of existing 
technologies (e.g., GDI, turbocharging, downsized engines) will create 
significant uncertainties for manufacturers about in-use performance 
over the vehicle's useful life. We are finalizing as proposed a 
temporary in-use FTP standard for PM of 6 mg/mi for all light duty 
vehicles certified to the Tier 3 full useful life 3 mg/mi standard. 
Since the Tier 3 FTP PM standard has a percent phase-in schedule spread 
over several years, starting in 2017 with full phase-in completed in 
2022, we are finalizing the requirement that the in-use standard apply 
to all vehicles certified to the new PM standards during the entire 
percent phase-in period (i.e., through MY 2021).
    We also proposed temporarily-relaxed in-use US06 PM standards. As 
described

[[Page 23480]]

in Section IV.A.4.b above, we are finalizing an in-use US06 PM standard 
of 10 mg/mi for the intermediate years of the program (MYs 2019 through 
2023) in response to industry concerns about emissions variability as 
the new standards become effective.
j. FFVs
    Because of the physical and chemical differences in how emissions 
are generated and controlled between vehicles operating on different 
blends of gasoline and ethanol, manufacturers of vehicles designed for 
high-percentage blends of ethanol (usually called Flexible Fuel 
Vehicles, or FFVs) may face unique compliance challenges under the Tier 
3 program. Historically, under the Tier 2 program, FFVs have only been 
required to meet all Tier 2 emission standards, FTP and SFTP, while 
operating on gasoline (E0); when operating on the alternative fuel 
(generally this means a blend that is nominally 85 percent ethanol, or 
E85), they have only been required to meet the FTP emission standards.
    However, E85 use may rise considerably in the future as ethanol use 
increases in response to the Renewable Fuels Standards (RFS). Thus, as 
the Tier 3 program is implemented, it is increasingly important that 
FFVs maintain their emission performance when operating on E85 across 
different operating conditions.
    We believe that at standard test conditions, requiring 
manufacturers to meet the Tier 3 standards on any blend of gasoline and 
ethanol will not be significantly more challenging technologically than 
compliance on lower ethanol blends, including the E10 Tier 3 test fuel 
we are adopting. We are thus finalizing, as proposed, the requirement 
that in addition to complying with the Tier 3 requirements when 
operating on Tier 3 test fuel, FFVs also comply with both the FTP and 
the SFTP emission standards when operating on E85. This includes the 
requirement to meet emission standards for both Tier 3 test fuel and 
E85 for the FTP, highway test, and SFTP emission standards at standard 
test temperatures (i.e., 68 [deg]F to 86 [deg]F). Since FFVs can 
operate on any blend of gasoline and ethanol (up to a nominal 85 
percent ethanol), the emission requirements apply to operation at all 
levels of the alternative fuel that can be achieved with commercially 
available fuels. However, for exhaust emission compliance demonstration 
purposes, we will test on Tier 3 test fuel and on fuel with the highest 
available ethanol content.
k. Credit for Direct Ozone Reduction (DOR) Technology
    Since the late 1990s, technologies have been commercialized with 
which vehicles can remove ozone from the air that flows over the 
vehicle's coolant radiator. In such direct ozone reduction (DOR) 
technology, a catalytic coating on the radiator is designed to convert 
ambient ozone into gaseous oxygen, as a way of addressing the air 
quality concerns about ozone. Detailed technical analyses for the 
California LEV II and the federal Tier 2 programs showed that when 
properly designed these systems can remove sufficient ozone from the 
air to be equivalent to a quantifiable reduction in tailpipe NMOG 
emissions. In the earlier programs, both California and EPA provided 
methodologies through which a manufacturer could demonstrate the 
capability and effectiveness of the ozone-reducing technology and be 
granted an NMOG credit. A small number of vehicle models with DOR 
applications received credit under the LEV II program; no manufacturer 
formally applied for credits under the federal Tier 2 program.
    Some manufacturers have expressed an interest in the continued 
availability of a DOR credit as a part of their potential LEV III and 
Tier 3 compliance strategies. EPA believes that when a DOR system is 
shown to be effective in reducing ozone, a credit toward Tier 3 
compliance is warranted. We are finalizing a provision, as proposed, 
that manufacturers following the California methodology for 
demonstrating effectiveness and calculating a appropriate credit for a 
DOR system be granted a specific credit toward the NMOG portion of the 
NMOG+NOX standard.\334\ As with the California program, such 
a credit may not exceed 5 mg/mi NMOG.
---------------------------------------------------------------------------

    \334\ EPA is incorporating the CARB DOR methodology by 
reference.
---------------------------------------------------------------------------

l. Credit for Adopting a 150,000-Mile Emissions Warranty
    Under the Tier 3 standards, manufacturers are expected to design 
their emission control systems to continue to operate effectively for a 
useful life of 150,000 miles (120,000 miles for some smaller vehicles). 
However, manufacturers are only required to replace failed emission 
control components or systems on customers' vehicles for a limited time 
period, specified in the Clean Air Act (80,000 miles/8 years for key 
emission control components). EPA believes that voluntary extension of 
this warranty obligation by manufacturers would provide additional 
emission reductions by helping ensure that controls continue to operate 
effectively in actual operation through the full life of the vehicle.
    We are finalizing as proposed that a manufacturer providing its 
customers with a robust emission control system warranty of 15 years or 
150,000 miles be eligible for a modest credit of 5 mg/mi 
NMOG+NOX.\335\ Because of the significant liability that 
manufacturers would be accepting, we do not expect that the use of this 
credit opportunity will be widespread. However, based on our modeling 
of the expected deterioration of the emissions of future Tier 3 
vehicles absent repair/replacement of failed emission controls, we 
anticipate that the value to the environment of long emissions 
warranties in terms of reduced real-world emissions would significantly 
exceed the 5 mg/mi NMOG+NOX credit.\336\
---------------------------------------------------------------------------

    \335\ Manufacturers choosing to comply with the standards for a 
120,000 mile useful life for their LDVs and LDT1s are not eligible 
for this extended warranty credit for those vehicles.
    \336\ Beardsley, M, et al. (2013, February). Updates to MOVES 
for the Tier 3 NPRM. Memorandum to the docket.
---------------------------------------------------------------------------

    We will use the same criteria for approving such a credit as does 
the parallel California program.\337\ Thus, in addition to committing 
to customers that failing emission controls will be repaired or 
replaced for 15 years/150,000 miles, manufacturers will also need to 
accept the liability that in the event that a specific emissions 
control device fails on greater than 4 percent of a vehicle model's 
production, they will recall the entire production of that model for 
repair.
---------------------------------------------------------------------------

    \337\ EPA is incorporating the CARB extended emission warranty 
provisions by reference.
---------------------------------------------------------------------------

m. Averaging, Banking, and Trading of Credits
    We proposed and are finalizing an averaging, banking, and trading 
(ABT) program similar to those that have historically been a part of 
most EPA emission control programs. For the Tier 3 final rule, the ABT 
program is consistent with the other Tier 3 program elements, the heavy 
duty exhaust emission standards and the evaporative emission standards 
programs, with the only exception being credit life during the longer 
phase in for the light duty program as described below. The ABT program 
is intended to provide an opportunity for manufacturers to deploy their 
Tier 3 vehicle models more efficiently, especially during the 
transition years, and to avoid excessive delays in the necessary 
technological improvements across the fleet. We have

[[Page 23481]]

designed the Tier 3 ABT program to provide for credits to be generated 
by certifying vehicles that perform better than the fleet-average 
NMOG+NOX standards. These credits may be used within a 
company to offset vehicles that perform worse than the standards, they 
may be banked for later use, or they may be traded to other 
manufacturers.
    We are also finalizing limitations on the use of credits for the 
light-duty fleet. We proposed that Tier 3 credits expire after 5 model 
years following the model year they are generated and solicited comment 
on the Tier 3 credit life. In communications regarding the proposed 
rule, representatives of the auto industry expressed to EPA that the 
value of the ABT program during the MY 2017-2025 phase-in of the 
primary program would be improved if credits had a longer credit 
life.\338\ We determined that, with certain restrictions, Tier 3 credit 
life can be temporarily extended with no adverse impacts on the overall 
emission reductions of the program. Specifically, we are finalizing a 
credit life of 8 years for credits generated in MYs 2017-2022 for the 
FTP and SFTP NMOG+NOX fleet average standards for the 
primary program only. For the heavier light-duty vehicles, the 8-year 
credit life begins for credits generated in MY 2018. Note that, as 
proposed, credits generated under the Early Tier 3 Credit provision 
(Section IV.A.7.a) are limited to 5-year life, and are not affected by 
the longer credit life.
---------------------------------------------------------------------------

    \338\ Passavant, G. (January 2014), Meetings with Chrysler--Tier 
3 NPRM Lead Time and ABT, Memorandum to Docket.
---------------------------------------------------------------------------

    For credits generated in MYs 2023-2025, the credit life declines by 
one year of credit life annually, with credit life stabilizing at 5 
years for credits generated in MYs 2025 and later. That is, credits 
generated in MY 2023 have a 7-year life, in MY 2024 a 6-year life, and 
in MY 2025 and later a 5-year life. However, while credits can be 
generated, banked, and used internally for the extended time periods, 
credits cannot be traded to other manufacturers after 5 years.
    After considering the views expressed by manufacturers as well as 
the implementation schedules of this Tier 3 rule and the 2017 light-
duty GHG rule, we believe that the temporary up-to-8-year credit life 
available to manufacturers during the phase-in period provides 
substantial flexibility to address manufacturer uncertainties about 
future technology development and product planning during 
implementation of the Tier 3 program. We also believe this longer 
credit life provision will alleviate most if not all concerns expressed 
by manufacturers with respect to the challenges they may encounter by 
simultaneous implementation of the two programs.
    As proposed, we are finalizing a provision for a manufacturer to 
create a credit deficit, at certification or at the end of the 
production year, if its fleet average emissions exceed the standard. A 
manufacturer would be required to use all of its banked credits, if 
any, before creating a credit deficit. A credit deficit would need to 
be resolved before the fourth model year after the deficit was created; 
that is, a manufacturer may not maintain a credit deficit more than 3 
consecutive model years.
n. Tier 3 Transitional Emissions Bins
    During the development of the proposed rule and in their comments, 
manufacturers pointed out that they may continue to produce some 
vehicles as late as MY 2019 that could be certified to Tier 2 Bin 3 or 
Bin 4 standards. In order to provide manufacturers flexibility in 
meeting the fleet average standards and to further facilitate the 
transition, we will allow manufacturers to certify to the combined 
NMOG+NOX levels of these Tier 2 bins through MY 2019. We are 
finalizing two transitional Tier 3 bins, Bin 110 and Bin 85, that have 
FTP NMOG+NOX standards of 110 mg/mi and 85 mg/mi, 
respectively (i.e., the sum of the NMOG and NOX values from 
the Tier 2 bins). The associated FTP standards for CO, PM, and HCHO 
corresponding to these bins are identical to those for vehicles 
certified to the Tier 3 Bin 125. Tier 3 SFTP standards will apply to 
these vehicles, and these vehicles will be included in the Tier 3 PM 
percent phase-in calculations.
o. Compliance Demonstration
    In general, we are finalizing requirements that manufacturers 
demonstrate compliance with the Tier 3 light-duty vehicle emission 
standards in a very similar manner to existing Tier 2 vehicle 
compliance (see Sec.  86.1860 of the regulatory language). However, for 
Tier 3, manufacturers must calculate their compliance with the fleet 
average standards and percent phase-in standards based on annual 
nationwide sales, including sales in California and Clean Air Act 
Section 177 states. We believe that this approach represents another 
step toward achieving the goal of an effectively nationwide program as 
early as possible, which has been a basic principle in EPA's 
development of this program and broadly supported by vehicle 
manufacturers. We also believe that basing compliance on nationwide 
sales may reduce the need for manufacturers to project future sales and 
track past years' sales in a disaggregated way. Because the Tier 3 
provisions become increasingly consistent with LEV III provisions as 
the Tier 3 program phases in, we believe that any disproportionate 
impacts of different mixes of vehicles in different states are unlikely 
to occur.
    This nationwide compliance calculation approach applies to vehicles 
as they become subject to the Tier 3 provisions, either the declining 
fleet-average NMOG+NOX curves or the percent phase-in PM 
standards. Were any manufacturer to choose to use the alternative FTP 
and SFTP phase-ins, which are not a part of the LEV III program, the 
manufacturer would not include sales in California or in the Section 
177 states in its compliance calculations.

B. Tailpipe Emissions Standards for Heavy-Duty Vehicles

1. Overview and Scope of Vehicles Regulated
    After considering the comments we received, we are adopting the 
Tier 3 exhaust emissions standards that we proposed for chassis-
certified heavy-duty vehicles (HDVs) between 8501 and 14,000 lbs gross 
vehicle weight rating (GVWR). Vehicles in this GVWR range are often 
referred to as Class 2b (8501-10,000 lbs) and Class 3 (10,001-14,000 
lbs) vehicles, and are typically full-size pickup trucks and work vans 
certified as complete vehicles.\339\ Medium-duty passenger vehicles 
(MDPVs), although in the Class 2b GVWR range, are subject to Tier 3 
standards discussed in Section IV.A. To a large extent, we are also 
adopting the Tier 3 certification testing and compliance provisions 
that we proposed for HDVs. There are, however, a number of improvements 
we are making in response to comments, as discussed in detail below.
---------------------------------------------------------------------------

    \339\ 40 CFR 86.1803-01 defines HDVs to also include motor 
vehicles at or below 8,500 lbs GVWR that have a vehicle curb weight 
of more than 6,000 lbs or a basic vehicle frontal area in excess of 
45 square feet, and these vehicles will also be subject to the Tier 
3 standards and other provisions applicable to Class 2b vehicles 
discussed in this section.
---------------------------------------------------------------------------

    The Tier 3 program for HDVs will bring substantial reductions in 
harmful emissions from this large fleet of work trucks and vans, a 
fleet that is used extensively on every part of the nation's highway, 
rural, and urban roadway system. The fully-phased in Tier 3 standards 
levels for non-methane organic gas (NMOG) plus oxides of nitrogen 
(NOX), and for particulate matter (PM), are on the order of 
60 percent lower than the current standards levels.

[[Page 23482]]

    We proposed to require that diesel-fueled Class 2b and 3 complete 
vehicles, like their gasoline-fueled counterparts, be certified to the 
Tier 3 standards on the chassis test; we also proposed to include these 
vehicles in the Tier 3 HDV averaging, banking, and trading (ABT) 
program. Currently only gasoline-fueled Class 2b/3 complete HDVs are 
required to chassis certify.
    The International Council for Clean Transportation (ICCT) provided 
comments in support of this requirement, arguing that it is needed to 
stop manufacturers from making trucks marginally above 8500 lbs GVWR to 
avoid light-duty emission standards. The Truck and Engine Manufacturers 
Association (EMA) opposed mandatory chassis certification for any class 
of engines or vehicles over 8500 lbs GVWR, arguing that the existing 
flexibility is needed to minimize unnecessary costs and certification 
burdens. EMA commented that, at a minimum, EPA should maintain optional 
certification of diesel engines used in complete Class 3 vehicles. In 
their joint comments, the Alliance of Automobile Manufacturers and the 
Association of Global Automakers also requested that EPA retain the 
option for complete Class 3 diesel vehicles and engines, arguing that 
otherwise manufacturers may be required to dual certify vehicle models 
that include variants both under and over 14,000 lbs.
    We are sensitive to this issue but remain concerned that the fleet 
average standard program we are finalizing would not work well if a 
major fleet component, such as complete Class 3 diesel trucks, can be 
left in or taken out of the fleet calculation based on what each 
manufacturer considers to be most advantageous. We believe the 
resulting competitive issues and uncertainties would be problematic, 
given the wide variance in gasoline/diesel HDV sales among the 
manufacturers, our provision for averaging across each manufacturers' 
entire Class 2b/3 fleet, and the overwhelming preponderance of diesels 
in the Class 3 market. It would also create uncertainties in the Tier 3 
environmental benefits, given the pronounced difference between these 
Tier 3 standards and the heavy-duty diesel engine standards we set 13 
years ago, which we expect to remain in effect for the foreseeable 
future.
    As a result, we are finalizing these provisions as proposed, except 
that we are providing that manufacturers, instead of certifying 
complete diesel Class 3 HDVs, may install diesel engines that have been 
engine-certified for any model year that the engine family has less 
than half of its sales being installed in such non-chassis-certified 
complete Class 3 vehicles. For example, if a company has a certified 
diesel engine family with 10,001 sales in MY 2020, up to 5,000 of those 
engines may be installed in complete Class 3 HDVs that are not chassis-
certified for exhaust emissions. This provision is intended to help 
address manufacturers' concern about dual certification, while at the 
same time ensuring a coherent fleetwide standards regimen in this 
vehicle class. It also better harmonizes with California's low-emission 
vehicle (LEV) III program which does not mandate chassis certification 
for diesel Class 3 vehicles. By only allowing engine-certified vehicles 
in the case of engines that are primarily produced for other purposes, 
we believe this approach adequately guards against potential abuse. In 
the case of complete diesel Class 3 HDVs produced by a company other 
than the engine certifier, the responsibility for ensuring the sales 
limit is not exceeded remains with the vehicle manufacturer, who will 
need to coordinate with the engine supplier to ensure compliance.
    Manufacturers of incomplete HDVs that are sold to secondary 
manufacturers for subsequent completion (less than 10 percent of the 
Class 2b and 3 U.S. market) are also allowed under existing EPA 
regulations to certify via either the chassis or engine test, and those 
who choose to chassis-certify in the future will be subject to Tier 3 
requirements. We asked for comment on mandating chassis certification 
of incomplete Class 2b and 3 vehicles, noting that California's LEV III 
program includes such a requirement for Class 2b. Commenters expressed 
opposition to this extension of mandatory chassis certification, 
despite their general support for harmonization with LEV III; as a 
result, we are not mandating chassis certification for any incomplete 
HDVs.
    The key elements of the Tier 3 program for HDVs parallel those for 
passenger cars and light-duty trucks (LDTs), with adjustments in 
standards levels, emissions test requirements, and implementation 
schedules, appropriate to this sector. These key elements include:
     A combined NMOG+NOX declining fleet average 
standard beginning in 2018 and reaching the final, fully phased-in 
level in 2022,
     creation of a bin structure for standards, including 
standards for carbon monoxide (CO) and formaldehyde,
     PM standards phasing in separately on a percent-of-sales 
basis,
     changes to the test fuel for gasoline- and ethanol-fueled 
vehicles,
     extension of the regulatory useful life to 150,000 miles,
     a new requirement to meet standards over the supplemental 
federal test procedure (SFTP) that addresses real-world driving modes 
not well-represented by the federal test procedure (FTP) cycle alone, 
and
     special flexibility provisions for small businesses and 
small volume manufacturers described in Section IV.G.
    As in the light-duty Tier 3 program, we have put a strong emphasis 
on coordinating HDV Tier 3 program elements with California's LEV III 
program for Class 2b and 3 vehicles, referred to in LEV III as medium-
duty vehicles (MDVs). The goal is to create a coordinated ``national 
program'' in which California would accept compliance with Tier 3 
standards as sufficient to also satisfy LEV III requirements, thus 
allowing manufacturers to comply nationwide by marketing a single 
vehicle fleet. As part of this effort, we proposed that manufacturers 
of Tier 3 HDVs calculate compliance with the fleet average standards 
and percent phase-in standards based on annual nationwide sales, 
including sales in California and in states implementing California 
standards under Clean Air Act section 177. Commenters expressed 
emphatic support for this approach and we are finalizing it as a key 
element of the Tier 3 program.
2. HDV Exhaust Emissions Standards
a. Bin Standards
    Manufacturers will certify HDVs to Tier 3 requirements by having 
them meet the standards for NMOG+NOX, PM, CO and 
formaldehyde for one of the bins listed in Table IV-13. Manufacturers 
choose bins for their vehicles based on their product plans and 
corporate strategy for compliance with the fleet average standards 
discussed in Section IV.B.2.b, and once a vehicle's bin is designated, 
those bin standards apply throughout its useful life. Because the fleet 
average standards become more stringent over time, the bin mix will 
gradually shift from higher to lower bins.
    As in the past, there are numerically higher standards levels for 
Class 3 vehicles than for Class 2b vehicles, reflective of the added 
challenge in reducing per-mile emissions from large work trucks 
designed to carry and tow heavier loads. Also, the standards levels for 
both Class 2b and Class 3 HDVs are significantly higher than those 
being adopted for light-duty trucks due to marked differences in 
vehicle size and

[[Page 23483]]

capability, and to our requirement to test HDVs in a loaded condition 
(at the adjusted loaded vehicle weight (ALVW)). By conducting emissions 
testing with loaded vehicles, the heavy-duty program ensures that 
emissions controls are effective when these vehicles are performing one 
of their core functions: hauling heavy loads. This is a key difference 
between the heavy-duty and light-duty truck programs. The bin structure 
and standards levels are consistent with those in California's LEV III 
program. We requested comment on the usefulness of creating additional 
bins between Bin 0 and the next lowest bin in each vehicle class, as a 
means of encouraging clean technologies and adding flexibility, but 
commenters saw no need for these.

                                       Table IV-13 FTP Standards for HDVs
----------------------------------------------------------------------------------------------------------------
                                                   NMOG+NOX (mg/                                   Formaldehyde
                                                        mi)         PM (mg/mi)       CO (g/mi)        (mg/mi)
----------------------------------------------------------------------------------------------------------------
                                         Class 2b (8501-10,000 lbs GVWR)
----------------------------------------------------------------------------------------------------------------
Bin 395 (interim)...............................             395               8             6.4               6
Bin 340 (interim)...............................             340               8             6.4               6
Bin 250.........................................             250               8             6.4               6
Bin 200.........................................             200               8             4.2               6
Bin 170.........................................             170               8             4.2               6
Bin 150.........................................             150               8             3.2               6
Bin 0...........................................               0               0               0               0
----------------------------------------------------------------------------------------------------------------
                                        Class 3 (10,001-14,000 lbs GVWR)
----------------------------------------------------------------------------------------------------------------
Bin 630 (interim)...............................             630              10             7.3               6
Bin 570 (interim)...............................             570              10             7.3               6
Bin 400.........................................             400              10             7.3               6
Bin 270.........................................             270              10             4.2               6
Bin 230.........................................             230              10             4.2               6
Bin 200.........................................             200              10             3.7               6
Bin 0...........................................               0               0               0               0
----------------------------------------------------------------------------------------------------------------

    The NMOG+NOX standards levels for the highest bins in 
each class (Class 2b Bin 395 and Class 3 Bin 630) are equal to the sum 
of the current non-methane hydrocarbon (NMHC) and NOX 
standards levels that took full effect in 2009, as well as to 
equivalent LEV standards in California's LEV II program. These bins are 
intended as carryover bins. That is, we expect them to be populated 
with vehicles that are designed to meet the current standards, and that 
are being phased out as new lower-emitting vehicle designs phase in to 
satisfy the Tier 3 fleet average NMOG+NOX standard. We also 
consider the next highest bins (Class 2b Bin 340 and Class 3 Bin 570) 
to be carryover bins, because they likewise can be readily achieved by 
vehicles designed for today's EPA and California LEV II emissions 
programs. As the 2018-2022 phase-in progresses, it will become 
increasingly difficult to produce vehicles in these bins and still meet 
the fleet average standard. Therefore vehicles in these bins (as well 
as some others not yet designed to meet Tier 3 PM standards described 
in Section IV.B.2.d) will be considered ``interim Tier 3'' vehicles, 
and the bins themselves will be considered ``interim bins.''
    To facilitate their use in this carryover function, the interim 
bins do not require manufacturers to meet Tier 3 exhaust emissions 
standards on the SFTP, over the longer useful life, or with the new 
gasoline test fuel discussed in Section IV.F, although testing on this 
fuel will be allowed. These requirements do apply in all other bins.
    In the context of these relaxed requirements for the interim bins, 
we proposed two additional measures to help ensure these bins are 
focused on their function of helping manufacturers transition to the 
long-term Tier 3 emissions levels. First, we proposed that the interim 
bins would be available only in the phase-in years of the program; that 
is, through model year (MY) 2021, as is appropriate to their interim 
status. Second, vehicles in the interim bins would meet separate NMOG 
and NOX standards rather than combined NMOG+NOX 
standards. The goal was to ensure that a manufacturer does not redesign 
or recalibrate a vehicle model under combined NMOG+NOX Tier 
3 standards for such purposes as reducing fuel consumption, through 
means that result in higher NOX or NMOG emissions than 
exhibited by today's vehicles, contrary to the intended carryover 
function of the interim bins. Industry commenters objected to both the 
proposed sunsetting of the interim bins and the proposed separate 
NOX and NMOG standards, arguing that they overly restrict 
manufacturer flexibility and work against harmonization with LEV III. 
However, commenters did not address EPA's concern regarding increased 
NOX emissions at the interim bin levels.
    After considering the comments, we believe a modified approach to 
the interim bins can at least partly address the industry concerns 
regarding harmonization while still precluding backsliding on 
NOX levels. We are finalizing the interim bins with combined 
NMOG+NOX standards as requested by the commenters, but are 
adopting a restriction on deterioration-adjusted NOX levels 
in certification testing, to the levels allowed under the current 
standards in 40 CFR 86.1816-08. These are 0.2 and 0.4 g/mi for Class 2b 
and Class 3, respectively. This restriction will not apply to vehicles 
in use, and does not impose a parallel NMOG restriction. Given our 
continuing concerns about NOX increases that would be 
allowed by the combined standards at the interim bin levels, we believe 
that this approach and the associated certification burden are 
reasonable, noting that manufacturers already must obtain 
NOX test results in certifying to an NMOG+NOX 
standard, and the differing NOX and NMOG deterioration 
mechanisms will likely dictate that they be considered separately in 
obtaining deteriorated NMOG+NOX levels for certification.
    We believe that making the interim bins available indefinitely 
would run counter to their limited purpose as an aid to making the 
transition to Tier 3

[[Page 23484]]

emissions levels. Making these bins permanent would, we believe, 
necessitate that they take on other key elements of the Tier 3 program 
such as longer useful life, SFTP compliance, and the use of Tier 3 test 
fuel. These requirements in turn would negate the usefulness of these 
bins in helping to carry over some pre-Tier 3 vehicle designs during 
the transition years in which the declining fleet average standard 
levels are high enough to accommodate their continued sale. By MY 2022, 
the fleetwide standard will be stringent enough to effectively 
eliminate the ability of manufacturers to use interim bins while 
meeting the declining fleet average standard levels. We are therefore 
adopting the sunsetting of the interim bins as proposed, making them 
available only through MY 2021.
b. Fleet Average NMOG+NOX Standards
    As in the light-duty Tier 3 program, a key element of the program 
we are finalizing for HDVs is a fleet average NMOG+NOX 
standard that becomes more stringent in successive model years: in the 
case of HDVs, from 2018 to 2022. Each HDV sold by a manufacturer in 
each model year contributes to this fleet average based on the mg/mi 
NMOG+NOX level of the bin declared for it by the 
manufacturer. Manufacturers may also earn or use credits for fleet 
average NMOG+NOX levels below or above the standard in any 
model year, as described in Section IV.B.4. As proposed, we are 
adopting the separate Class 2b and Class 3 fleet average standards 
shown in Table IV-14, though a manufacturer can effectively average the 
two fleet classes using credits (see Section IV.B.4). We believe this 
split-curve approach is superior to a single phase-in covering all HDVs 
because it recognizes the different Class 2b/Class 3 fleet mixes among 
manufacturers and the differing challenge in meeting mg/mi standards 
for Class 3 vehicles compared to Class 2b vehicles, while still 
allowing for a corporate compliance strategy based on a combined HDV 
fleet through the use of credits.
    We are adopting the proposed fleet average NMOG+NOX 
standards. These are consistent with those set for the LEV III MDV 
program in model years 2018 and later. As proposed, we are also 
adopting provisions allowing manufacturers to voluntarily meet bin and 
fleet average standards in model years 2016 and 2017 that are 
consistent with the MDV LEV III standards in those years, for the 
purpose of generating credits that can be used later or traded to 
others. These voluntary standards are shown in Table IV-14. This 
voluntary opt-in program serves the important purpose of furthering 
consistency between the federal and California programs, such that 
manufacturers who wish to can produce a single vehicle fleet for sale 
nationwide, with the opportunity for reciprocal certification in 
affected model years. It further incentivizes pulling ahead of Tier 3 
technologies, with resulting environmental benefits, by providing for 
early compliance credits in this nationwide fleet. Commenters expressed 
support for this harmonized array of HDV emissions standards.
    Manufacturers choosing to opt into this early compliance program 
could start in either model year 2016 or 2017. They would have to meet 
the full complement of applicable bin standards and requirements for 
the bins they choose for their vehicles in meeting the 2016/2017 MY 
fleet average FTP NMOG+NOX standards, including SFTP 
standards in the bins that have SFTP standards. However, they do not 
need to meet the Tier 3 PM FTP and SFTP standards discussed in Sections 
IV.B.2.d and IV.B.3.a, or the evaporative emissions standards discussed 
in Section IV.C, because these requirements phase in on a later 
schedule. We are not extending the voluntary compliance opportunity to 
the 2015 model year, based on manufacturer comments indicating it would 
be of little value.

                                                    Table IV-14--HDV Fleet Average NMOG+NOX Standards
                                                                         [mg/mi]
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Voluntary
                                                                Required program
--------------------------------------------------------------------------------------------------------------------------------------------------------
Model Year.....................            2016            2017            2018            2019            2020            2021  2022 and later.
Class 2b.......................             333             310             278             253             228             203  178.
Class 3........................             548             508             451             400             349             298  247.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We believe that the voluntary program provisions will benefit the 
environment, the regulated industry, and vehicle purchasers, because it 
has potential to accomplish early emissions reductions while 
maintaining the goal of a cost-effective, nationwide vehicle program in 
every model year going forward.
    Although manufacturers will be allowed to meet the fleet average 
NMOG+NOX standard through whatever combination of bin-
specific vehicles they choose, it is instructive to note that the fully 
phased in fleet average standard for model years 2022 and later will be 
the equivalent of a Class 2b fleet mix of 90 percent Bin 170 and 10 
percent Bin 250 vehicles, and a Class 3 fleet mix of 90 percent Bin 230 
and 10 percent Bin 400 vehicles. Therefore, it is appropriate to 
consider Bin 170 Class 2b vehicles and Bin 230 Class 3 vehicles to be 
representative of Tier 3-compliant HDVs in the long term.
c. Alternative NMOG+NOX Phase-In
    We believe the fleet average phase-in described above will be 
flexible, effective, and highly compatible with manufacturers' desire 
to market vehicles nationwide, because of its close alignment with 
California's LEV III program for medium-duty vehicles. However, for any 
HDV manufacturers seeking four years of lead time and three years of 
stability as specified in Clean Air Act section 202(a)(3)(C), we 
proposed an alternative compliance path.\340\ This alternative approach 
was crafted to be equivalent to the NMOG+NOX declining fleet 
average in the above-described LEV III-harmonized alternative in every 
model year, except that the period for the voluntary program in the 
alternative approach would extend an extra model year--through 2018. To 
ensure that this approach meets the Act's stability requirement, 
instead of being structured around an annually declining fleet average 
standard, the alternative approach requires a manufacturer to 
demonstrate compliance (including through use of credits) with a 
schedule of annually increasing percent-of-sales of HDVs certified to 
the fully phased in 178 mg/mi (Class 2b) and 247 mg/mi (Class 3) 
standards, as shown in Table

[[Page 23485]]

IV-15. We are adopting the alternative percent-of-sales phase-in 
largely as proposed, with limited changes described below.
---------------------------------------------------------------------------

    \340\ For vehicles above 6,000 lbs GVWR, Clean Air Act section 
202(a)(3)(C) requires EPA to provide manufacturers with a minimum of 
4 years of lead time before mandatory changes to any standard 
applicable to hydrocarbon, NOX, carbon monoxide, or PM 
can be implemented, and 3 years of stability between changes to any 
such standard.

                                               Table IV-15--Percent-of-Sales Alternative NMOG+NOX Phase-In
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    Voluntary
                                                        Required program
--------------------------------------------------------------------------------------------------------------------------------------------------------
Model Year.....................            2016            2017            2018        \a\ 2019            2020            2021  2022 and later.
Class 2b.......................             29%             39%             54%             65%             77%             88%  100%.
Class 3........................             21%             32%             47%             60%             73%             87%  100%.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Special provisions apply to models with an early-starting 2019 model year.

    The availability of emissions averaging under our alternative 
phase-in, discussed below, makes the two alternatives functionally 
equivalent, not just in the annual emissions reductions they achieve, 
but also in how manufacturers may design their mix of products to meet 
the phase-in standards. Commenters who disagreed with this assessment 
for HDVs did not provide their reasoning, beyond referring to similar 
comments they had on the parallel light-duty (above 6000 lbs GVWR) 
alternative phase-in. However, that proposed alternative differs from 
the one we proposed for HDVs, and the elements in it that were found 
objectionable by the manufacturers are not in the HDV alternative. (See 
Section IV.A.3 for discussion of comments on the light-duty 
alternative.)
    Commenters objected that the proposed percent-of-sales alternative 
has not been shown by EPA to be feasible, or in fact is infeasible 
because it mandates the early phase-in of low-emitting vehicles 
certified to the final standards. Such comments miss the fact that, 
with ABT, every manufacturer can produce the same mix of vehicles in 
any model year to comply with either HDV phase-in alternative, with the 
exception that MY 2018 is a voluntary phase-in year under the 
alternative phase-in and a required year under the LEV III-harmonized 
phase-in. The ABT provisions enable a manufacturer to adopt a fleet 
average compliance strategy while utilizing the percent-of-sales phase-
in that is identical to what would be required under the LEV III-
harmonized phase-in's fleet average standards. By no means are 
manufacturers forced to make only vehicles certified to the final 
standards. The percent-of-sales phase-in is thereby no more stringent 
than the LEV III-harmonized phase-in, and the feasibility analysis 
provided in Section IV.B.5, which expressly addresses the LEV III-
harmonized phase-in, serves to demonstrate the feasibility of both 
alternatives.
    Some comments seem to assert that the percent-of-sales framework 
for the alternative was chosen by EPA to make this alternative so 
stringent (by requiring some vehicles to meet final standards four 
years early) that no reasonable company would use it. This is 
incorrect, both in regard to its actual effect (which as explained 
above is not more stringent), and in regard to our intent. The percent-
of-sales framework for the alternative was proposed and is being 
adopted for the purpose of providing manufacturers with a phase-in 
alternative that explicitly meets the applicable Clean Air Act 
stability requirement.
    We are making one change to the percent-of-sales alternative, 
necessitated by the fact that this final rule is being signed in 2014, 
not 2013 as envisioned in the proposal. HDV models for which the 2019 
model year begins before the fourth anniversary of the signature date 
of this final rule may be excluded from the Tier 3 fleet average 
compliance calculations and all other Tier 3 requirements. These 
excluded vehicles would instead need to comply with the applicable pre-
Tier 3 standards and requirements for the entire production of these 
models throughout the 2019 MY. This limited allowance ensures that the 
alternative meets EPA's obligation for four years of lead time under 
the Clean Air Act. It is similar to a phase-in alternative we provided 
in the light-duty vehicle Tier 2 rule (see 65 FR 6747, February 10, 
2000). Note that 40 CFR 86.1803-01 defines ``model year'' as ``the 
manufacturer's annual production period (as determined by the 
Administrator) which includes January 1 of such calendar year: Provided 
that if the manufacturer has no annual production period, the term 
`model year' shall mean the calendar year.'' Additional regulations 
pertaining to the definition of a model year are in 40 CFR 85, subpart 
X.
    This allowance remains optional within the percent-of-sales 
alternative--a manufacturer may voluntarily include these early-
starting 2019 MY vehicles in the Tier 3 program, and in this case these 
vehicles would be treated no differently under the alternative than 
vehicles with a later-starting 2019 MY, including with regard to 
whether manufacturers choose to make them part of the ``phase-in'' 
fleet (vehicles counting toward the phase-in percentages) or the 
``phase-out'' fleet (vehicles not counting toward the phase-in 
percentages).
    Although it is conceivable that manufacturers would commence an 
early start of the 2019 model year specifically for the purpose of 
delaying Tier 3 obligations, we do not think this is likely, given the 
many important constraints and decisions that typically factor into 
setting this date, and the fact that signature of this final rule is 
occurring relatively early in the calendar year, well before typical 
model year start dates. We believe this is a reasonable way to provide 
a viable percent-of-sales phase-in alternative that has four years of 
lead time without making the 2019 model year voluntary for all vehicles 
or putting new constraints on the timing of a manufacturer's model 
year.
    To help ensure that the percent-of-sales alternative is fully 
equivalent to the LEV III-harmonized alternative in terms of fleet-wide 
emissions control and technology mix choices, we are including some 
additional provisions, as proposed. First, the Tier 3 vehicles being 
phased in under the percent-of-sales alternative, in addition to 
meeting the fully phased-in FTP NMOG+NOX standards, must 
also meet all other FTP and (as described below) SFTP standards 
required by the LEV III-harmonized alternative. These include the CO 
and formaldehyde FTP standards, the 150,000 mile (15 year) useful life 
requirement, exhaust emissions testing with the new test fuel for 
gasoline- and ethanol-fueled vehicles discussed in Section IV.F, and 
the NMOG+NOX and CO SFTP standards in Table IV-16. The 
specific standards are those for the bins in these tables closest to 
the fully phased-in NMOG+NOX standards: Bin 170 for Class 2b 
and Bin 230 for Class 3. (The PM and evaporative emissions standards 
phase in on separate schedules under both alternatives, as discussed in 
Sections IV.B.2.d and IV.C.)

[[Page 23486]]

    Second, we are making an ABT program available for the percent-of-
sales alternative, structured like the one created for the LEV III-
harmonized alternative. This involves certifying the vehicles in a 
manufacturer's HDV fleet to the bin standards, and demonstrating 
compliance with the fleet average standards for the LEV III-harmonized 
alternative in each model year, including through the use of ABT 
credits as in the LEV III-harmonized alternative. We are using the 
fleet average calculation method for purposes of ABT because, as 
explained above, we have determined that making this demonstration is 
equivalent to demonstrating compliance with the percent-of-sales 
requirement, and we see no value in complicating the program with 
another set of calculations.
    However, we are establishing one difference between the LEV III-
harmonized and percent-of-sales alternatives with respect to ABT 
provisions. Unlike in the LEV III-harmonized alternative, manufacturers 
will not have to certify all vehicles into bins in order to take 
advantage of the ABT provisions under the percent-of-sales alternative. 
Rather they could choose to certify any ``phase-out'' vehicles (that 
is, those not counting toward the percent-of-sales phase-in) to the 
pre-Tier 3 NMHC and NOX standards, provided these vehicles 
do not have family emission limits (FELs) above those standards. These 
non-Tier 3 vehicles will not be subject to the Tier 3 standards or 
other vehicle-specific elements of the Tier 3 compliance program. There 
were no comments on these specific compliance and ABT provisions 
associated with the percent-of-sales alternative.
d. Phase-In of PM Standards
    Consistent with the light-duty Tier 3 program discussed in Section 
IV.A, we are phasing in the PM standards for HDVs as an increasing 
percentage of a manufacturer's production of chassis-certified HDVs 
(combined Class 2b and 3) per year. In addition to concerns regarding 
the availability and required upgrades of test facilities used for both 
light-duty and heavy-duty vehicle testing, manufacturers have expressed 
uncertainty about PM emissions with new engine and emissions control 
technologies entering the market as a result of new greenhouse gas 
(GHG) standards. Therefore we are adopting the same phase-in schedule 
as for the light-duty sector in model years 2018-2019-2020-2021: 20-40-
70-100 percent, respectively. This will apply to HDVs certified under 
either NMOG+NOX phase-in alternative. The California Air 
Resources Board (CARB) is phasing in the LEV III PM standards for HDVs 
on the same schedule, except that LEV III will also involve a 10 
percent PM phase-in in the 2017 model year. We asked for comment on our 
adding this to our voluntary program for 2017, but received no comments 
on it and are not including it in the Tier 3 program.
    For manufacturers choosing the declining fleet average 
NMOG+NOX compliance path, the PM phase-in requirement for 
HDVs will be completely independent of the NMOG+NOX phase-
in, with no requirement that both phase-ins be met on the same 
vehicles. As a result, vehicles certified to any of the bin standards 
for NMOG+NOX need not necessarily meet Tier 3 PM standards 
before the 2021 model year. Instead, the current 0.02 g/mi PM standard 
will apply for those vehicles not yet phased into the Tier 3 PM 
standards. We are requiring that manufacturers choosing the percent-of-
sales phase-in alternative for NMOG+NOX meet the PM phase-in 
requirements with only those vehicles certified to the Tier 3 
NMOG+NOX standard, except in the 2019 and earlier model 
years when the standards, including the PM standards, are voluntary, 
and in the 2021 model year when the 100 percent PM phase-in requirement 
exceeds the 87-88 percent NMOG+NOX phase-in requirement. 
This is appropriate given the ability of manufacturers to build 
``phase-out'' vehicles (those not counting toward the phase-in 
percentages) under the percent-of-sales NMOG+NOX alternative 
that are certified entirely to pre-Tier 3 standards while still 
participating in the Tier 3 ABT program, discussed above.
    We will consider any vehicle under either compliance path that is 
not certified to Tier 3 standards for PM and NMOG+NOX (as 
well as the other, concomitant Tier 3 standards and requirements such 
as the extended useful life), an ``interim Tier 3'' vehicle. This term 
also applies to vehicles certified in one of the interim bins, as 
discussed above.
    Note that compliance with Tier 3 evaporative emissions requirements 
follows a separate phase-in schedule as described in Section IV.C. As a 
result, a vehicle in an exhaust emissions family that the manufacturer 
has phased in to the new useful life and test fuel requirements may be 
in an evaporative emissions family that has not yet phased in the Tier 
3 useful life and test fuel for evaporative emissions compliance and 
testing.
i. Optional PM Phase-In
    The percent-of-sales phase-in schedule for the PM standard, 
described above, will allow manufacturers with multiple vehicle models 
to determine and plan the phase-in of those models based on anticipated 
sales volumes of each model. However, manufacturers certifying only a 
few vehicle models may not be able to take meaningful advantage of this 
schedule. This is because their limited number of models may force them 
to over-comply to reach the required minimum percentages, compared to a 
manufacturer with many vehicle models available from which to choose a 
phase-in pathway.
    For instance, a manufacturer with only two models that each equally 
account for 50 percent of its sales would be required to introduce (at 
least) one of the models in MY 2018 to meet the phase-in requirement of 
20 percent in the first year. At the 50 percent level, this model would 
then also meet the requirements for MY 2019 (40 percent). To meet the 
MY 2020 requirement of 70 percent of sales, however, the manufacturer 
would need to introduce the second Tier 3 vehicle that year. Thus the 
manufacturer would have introduced 100 percent of its Tier 3 models one 
year earlier compared to a manufacturer that was able to delay the 
final 30 percent of its fleet until MY 2021 by distributing its 
redesign of models over the entire phase-in period.
    To provide for more equal application of this benefit among all 
manufacturers in the early years of the program, we are adopting the 
proposed optional ``indexed'' phase-in schedule that could be used by a 
manufacturer to meet the phase-in requirements. A manufacturer that 
exceeds the phase-in requirements in any given year will be allowed to, 
in effect, offset some of the phase-in requirements in a later model 
year. The optional phase-in schedule will be acceptable if it passes a 
mathematical test. The mathematical test is designed to provide 
manufacturers a benefit from certifying to the standards at higher 
volumes than they are obligated to under the normal phase-in schedule, 
while ensuring that the overall population of complying vehicles at the 
end of the phase-in is roughly the same as under the fixed percentage 
approach. In this alternative approach, manufacturers will weight Tier 
3 PM-compliant vehicles in the earlier years by multiplying their 
percent phase-in by the number of years prior to MY 2022 (that is, the 
second year of the 100 percent phase-in requirement).

[[Page 23487]]

    The mathematical equation for applying the optional phase-in is as 
follows:

(4 x APP2018) + (3 x APP2019) + (2 x APP2020) + (1 x APP2021) >= 440,

where APP is the actual phase-in percentage for the referenced model 
year. The sum of the calculation will need to be greater than or equal 
to 440, which is the result when the optional phase-in equation is 
applied to the primary percent phase-in schedule (4 x 20% + 3 x 40% + 2 
x 70% + 1 x 100% = 440). Commenters supported this optional PM phase-in 
approach.
3. Supplemental FTP Standards for HDVs
    Unlike passenger cars and light trucks, HDVs are not currently 
subject to SFTP standards. SFTP standards are intended to ensure 
vehicles have robust emissions control over a wide range of real-world 
driving patterns not well-covered by the FTP drive cycle. Even though 
HDVs are not typically driven in the same way as passenger cars and 
LDTs, especially as they frequently carry or tow heavy loads, we 
believe some substantial portion of real world heavy-duty pickup and 
van driving is not well-represented on the FTP cycle.
    The goal in setting the SFTP standards levels is not to force 
manufacturers to add expensive new control hardware for off-FTP cycle 
conditions, but rather to ensure a robust overall control program that 
precludes high off-FTP cycle emissions by having vehicle designers 
consider them in their choice of compliance strategies. High off-FTP 
cycle emissions, even if encountered relatively infrequently in real-
world driving, could create a substantial inadequacy in the Tier 3 
program, which aims to achieve very low overall emissions in use. The 
SFTP provisions will also help make the HDV program more consistent 
with the heavy-duty engine program, which for several years has 
included ``not-to-exceed'' provisions to control off-cycle emissions. 
Therefore, in addition to the SFTP provisions, we are further limiting 
enrichment on spark ignition engines in all areas of operation unless 
absolutely necessary.
a. SFTP NMOG+NOX, PM and CO Standards
    The SFTP standards levels are provided in Table IV-16. These are 
consistent with those adopted in the LEV III program.

                                      Table IV-16--SFTP Standards for HDVs
----------------------------------------------------------------------------------------------------------------
                   Vehicles in FTP bins                     NMOG+NOX (mg/mi)     PM (mg/mi)         CO (g/mi)
----------------------------------------------------------------------------------------------------------------
                                    Class 2b with hp/GVWR <= 0.024 hp/lb \a\
----------------------------------------------------------------------------------------------------------------
FTP Bins 200, 250.........................................               550                 7              22.0
FTP Bins 150, 170.........................................               350                 7              12.0
----------------------------------------------------------------------------------------------------------------
                                                    Class 2b
----------------------------------------------------------------------------------------------------------------
FTP Bins 200, 250.........................................               800                10              22.0
FTP Bins 150, 170.........................................               450                10              12.0
----------------------------------------------------------------------------------------------------------------
                                                     Class 3
----------------------------------------------------------------------------------------------------------------
FTP Bins 270, 400.........................................               550                 7               6.0
FTP Bins 200, 230.........................................               350                 7               4.0
----------------------------------------------------------------------------------------------------------------
\a\ These standards apply for vehicles optionally tested using emissions from only the highway portion of the
  US06 cycle.

    We are linking Tier 3 SFTP implementation for HDVs directly to the 
Tier 3 FTP phase-in and bins for these vehicles. That is, an HDV 
certified to any of the Tier 3 FTP bin standards must meet the SFTP 
standards for that bin as well. However, because the FTP PM standard 
phases in on a separate schedule, we will require that SFTP PM 
compliance be linked to the same schedule. That is, an HDV certified to 
the Tier 3 FTP PM standard must meet the applicable SFTP PM standard as 
well. This approach recognizes the complementary nature of FTP and SFTP 
provisions and helps to ensure that Tier 3 emissions controls are 
robust in real world driving. CARB expressed support in its written 
comments for this approach to linking FTP and SFTP requirements and an 
intent to propose aligning LEV III with it once the Tier 3 program is 
finalized.
    There are no SFTP requirements for the interim Tier 3 bins in each 
class (Class 2b Bins 340 and 395 and Class 3 Bins 570 and 630), because 
these are essentially carry-over bins from the previous standards to 
help facilitate the transition to Tier 3, and therefore are not 
intended to take on new requirements that might prompt a redesign. 
These implementation provisions are consistent with the approach taken 
in the LEV III program, except that California applies more of the Tier 
3 requirements for SFTP and extended useful life to vehicles in the 
interim bins.
    To help ensure a robust SFTP program that achieves good control 
over a wide range of real world conditions, we proposed to use a 
weighted-average composite SFTP cycle, with NMOG+NOX 
emissions calculated from results of testing over three cycles: the 
US06, the FTP, and the SC03, weighting these results by 0.28, 0.35, and 
0.37, respectively. However, at proposal, we determined that the full 
US06 component of the composite cycle, along with the ALVW loaded test 
condition, would not be sufficiently representative of real-world 
driving for two groups of HDVs: Those with low power-to-weight ratios 
and Class 3 vehicles.
    Therefore, as discussed in the proposal, SFTP testing of Class 2b 
vehicles with power-to-weight ratios at or below 0.024 hp/lb, may, at 
the manufacturer's option replace the full US06 component of the 
composite SFTP emissions with the test results from only the second of 
the three emissions sampling bags in the US06 test, generally referred 
to as the ``highway'' portion of the US06. HDVs so tested will be 
subject to the correspondingly lower SFTP standards levels shown in the 
table above. These vehicles will be driven during the test in the same 
way as the higher power-to-weight Class 2b vehicles (over the full US06 
cycle), using best effort (maximum power) if

[[Page 23488]]

the vehicle cannot maintain the driving schedule. The large majority of 
Class 2b vehicles--those with power-to-weight above 0.024 hp/lb--will 
be required to include emissions over the full US06 cycle in the 
composite SFTP. We believe that this approach provides a robust but 
repeatable and reliable test for the full range of Class 2b vehicles, 
as the highway portion of the US06 retains broad coverage of vehicle 
speed/acceleration combinations measured in real-world driving. Any 
testing conducted by EPA would follow the manufacturer's test path for 
the vehicle.
    For Class 3 vehicles, which range up to 14,000 lbs GVWR, we are 
also concerned that the full US06 cycle would not provide a 
representative drive cycle for SFTP testing. These vehicles are much 
larger than the light-duty vehicles that formed the basis for 
development of the US06 cycle, and loading them to ALVW for the SFTP 
test yields a very heavy test vehicle, not likely to be safely driven 
in the real world in a manner that is typified by this aggressive 
cycle. We believe that the LA-92 (or ``Unified'') driving cycle 
developed by CARB is more representative of Class 3 truck driving 
patterns and will produce more robust results for use in SFTP 
evaluations. Therefore we are adopting the proposed LA-92 cycle for use 
in place of the US06 component of the composite SFTP for Class 3 HDVs.
    HDVs do not have SC03 emissions requirements under the current HDV 
standards. Manufacturers of HDVs have indicated that they expect the 
SC03 emissions to be consistently lower than either the US06 or the FTP 
emissions levels, and therefore the added SC03 testing burden may be 
unnecessary. We are therefore providing HDV manufacturers with the 
option to substitute the FTP emissions levels for the SC03 emissions 
results for purposes of compliance. However, we will retain the ability 
to determine the composite emissions using SC03 test results in 
confirmatory or in-use testing. We received no adverse comments on this 
proposed approach.
    The set of composite SFTP cycles and standards we proposed and are 
adopting for HDVs is consistent with the MDV LEV III program. We 
received no adverse comments on them, except with regard to in-use 
testing as discussed in Section IV.B.6.a.
b. Enrichment Limitation for Spark-Ignition Engines
    To prevent emissions from excessive enrichment in areas not fully 
encountered in the SFTP cycles, we proposed and are adopting 
limitations in the frequency and magnitude of enrichment episodes for 
spark-ignition HDVs. These limitations are identical to those for 
light-duty vehicles. See Section IV.A.4.c for discussion of the 
requirements and relevant comments received.
4. HDV Emissions Averaging, Banking, and Trading
    This section describes how exhaust emissions credits may be earned 
and used. See Section V.C for similar provisions that apply for 
evaporative emissions. We are continuing the practice of allowing 
manufacturers to satisfy standards through the averaging of emissions, 
as well as through the banking of emissions credits for later use and 
the trading of credits with others.
    There are a number of facets of the Tier 3 ABT program for HDVs 
that are different from the existing program. First, instead of 
separate NMHC and NOX credits, manufacturers earn combined 
credits, consistent with the form of the standards.
    Second, manufacturers may accrue a deficit in their credit balance. 
Deficits incurred in a model year may be carried forward but a 
manufacturer will not be permitted to have a negative overall HDV 
credit balance in more than 3 consecutive model years. Manufacturers 
will have to use any new credits to offset any shortfall before those 
credits can be traded or banked for additional model years. Credits not 
used within 5 years after they are earned will be forfeited. These 5/3-
year credit/deficit life provisions are consistent with our light-duty 
Tier 3 approach, the California LEV III program for MDVs, and EPA 
programs for controlling GHG emissions from light- and heavy-duty 
vehicles.
    Third, as part of our new requirement for chassis certification of 
complete diesel HDVs, we are allowing the chassis-certified diesel HDVs 
to participate in the Tier 3 ABT program without restriction. Prior to 
Tier 3 they have not been allowed to earn or use ABT credits. We are 
not restricting or adjusting credit exchange between diesel and 
gasoline-fueled HDVs, consistent with our shift to combined 
NMOG+NOX standards that helps to ensure comparable 
stringency for these two engine types, and consistent also with the LEV 
III MDV program.
    Credits earned by a chassis-certified Tier 3 HDV may be used to 
demonstrate compliance with NMOG+NOX standards for any other 
chassis-certified Tier 3 HDV, regardless of size and without 
adjustment. This effectively allows manufacturers to plan a 
comprehensive HDV compliance strategy for their entire Class 2b and 
Class 3 product offering, by balancing credits so as to demonstrate 
compliance with the standards for both classes.
    Industry commenters argued that EPA should align the HDV credit 
provisions with the light-duty program by allowing early Tier 3 credits 
to be generated in MYs 2016 and 2017, calculated relative to the 
highest Class 2b and Class 3 bin NMOG+NOX levels (395 and 
630 mg/mi, respectively), and capped at a level proportional to the 
California level in MY 2018. However, these highest bin levels 
correspond to those of the existing HDV standards for NMHC and 
NOX, and are significantly higher than the MY 2016 and 2017 
LEV III levels. Thus vehicles designed to just meet the LEV III 
standards in these years could generate a large preliminary number of 
credits under the industry's Tier 3 early credits proposal, credits 
they would not earn in LEV III, thereby potentially thwarting the 
harmonization of the two programs. Truncating that credit bank for each 
manufacturer in 2018 such that it is proportional to their LEV III 
balance could perhaps, with additional restrictions on trading and 
banking, restore a harmonized credit status in that year. However, it 
constitutes an unnecessarily complex and uncertain pathway to the same 
result as that achieved under EPA's early opt-in provisions.
    Commenters requested that we provide for the conversion of pre-Tier 
3 HDV credits for use in Tier 3. However, as discussed in the proposal, 
we are not including provisions for doing so. We believe that by 
providing an early Tier 3 opt-in program for HDVs, capable of 
generating credits for two model years before the mandatory standards 
take effect (even longer under the alternative percent-of-sales phase-
in approach), we are giving ample opportunity for the manufacturers to 
accumulate early credits.
    Manufacturers commented that the proposed fleet average compliance 
approach is incongruous with California's LEV III method based on 
vehicle equivalent credits (VECs). Although expressing that they have 
no preference for the method since the stringency is equivalent, they 
recommended that EPA foster harmonization by providing a compliance 
option based on VECs. We believe that such an option would add 
unnecessary complexity to the Tier 3 program, and is made even more 
unnecessary by the intent expressed in CARB's written comments to 
propose a fleet average option for LEV III that is identical to EPA's 
approach.

[[Page 23489]]

    In the past we have set upper bounds, called family emission limit 
(FEL) caps, on how high emissions can be for credit-using vehicles, 
regardless of how many credits might be available. Under our Tier 3 bin 
structure, we believe that exhaust emission FEL caps are no longer 
relevant for Tier 3 HDVs, as every vehicle must meet whatever standards 
apply in the bin chosen for the vehicle by the manufacturer. (The bin 
standard becomes the effective FEL.) Indeed, because credits and 
deficits are calculated based on the difference between a 
manufacturer's fleet average emissions and the fleet average standards 
for a given model year, credits are not calculated for individual 
vehicle families at all. Thus the standard for NMOG+NOX in 
the highest allowable bin serves the purpose of the FEL caps in 
previous programs.
    Consistent with our proposal, we are not creating an averaging 
program for the HDV SFTP program, because we believe that the bin 
structure and FTP-centered NMOG+NOX ABT program provide 
adequate flexibility for smooth program implementation, especially in 
light of our aim to have the FTP standards be the primary technology 
forcers. A separate ABT program for SFTP compliance would add 
substantial complexity with little benefit, and, by making it possible 
to demonstrate robust SFTP emissions control on a vehicle that lacks 
commensurate FTP control, could prove at odds with the primary goal of 
the supplemental test for HDVs.
5. Feasibility of HDV Standards
    The feasibility assessment, discussed in more detail in Chapter 1 
of the RIA, recognizes that the Tier 3 program is composed of several 
new requirements for Class 2b and 3 heavy-duty vehicles, which include 
primarily large gasoline and diesel pick-up trucks and vans with 
diverse application-specific designs. These new exhaust emissions 
requirements include stringent NMOG+NOX and PM standards for 
the FTP and the SFTP, that will as a whole require new emissions 
control strategies and hardware in order to achieve the standards. The 
type of new hardware that will be required will vary depending on the 
specific application and emissions challenges. Additionally, gasoline 
and diesel vehicles will require different emissions control strategies 
and hardware. The level of stringency for the SFTP NMOG+NOX 
standards will generally only require additional precise control of the 
engine parameters not necessitated in the past because of the lack of 
SFTP requirements. Similarly, the new PM standards on both the FTP and 
SFTP cycles will require more precise control of engine operation on 
gasoline vehicles while diesels already equipped with diesel 
particulate filters will require minimal changes. The new PM standards 
may also require that manufacturers consider the durability of their 
engines to the 150,000 miles useful life requirement with respect to 
engine wear resulting in increased oil consumption and potentially 
higher PM emissions.
    In order to assess the technical feasibility of NMOG+NOX 
national fleet average FTP standards of 178 mg/mi for Class 2b vehicles 
and 247 mg/mi for Class 3 vehicles, we conducted an analysis of 
certification data for the HDVs certified in the 2010 and 2011 MYs. For 
this final rule, we also reviewed certification records for 2012 and 
2013 MY vehicles, and determined that these primarily involve carryover 
engines and emission control hardware. Therefore we did not update the 
NPRM analysis however any new or updated certification results in the 
2012 or 2013 MYs are included in the RIA chapter 1 discussion. This 
analysis provided a baseline for the current HDV fleet emissions 
performance, as well as the emissions performance specific to the Class 
2b and 3 vehicles. The emissions performance of each heavy-duty vehicle 
class specific to gasoline and diesel is shown in Table IV-17 below. It 
is important to note that the emissions results are only the 4000 mile 
test point results and do not incorporate any deterioration which 
manufacturers must account for when certifying to a full useful life 
standard. Designs limiting the deterioration of emission control 
hardware are critical to meeting the emission standards at the useful 
life of the Tier 3 program. Deterioration factors to adjust the values 
to the Tier 3 useful life standard of 150,000 miles were not available. 
However, deterioration factors to adjust to 120,000 miles useful life, 
and their implications for performance at higher miles, are discussed 
in the RIA Chapter 1.
    The analysis also reflects the importance of the combined 
NMOG+NOX standard approach, where diesels and gasoline HDVs 
can balance their combined NMOG and NOX levels. Diesel 
vehicles in the analysis produce very low NMHC emissions (NMOG is not 
reported for diesels) but higher NOX emissions, while 
gasoline vehicles have opposite performance. The combined standard 
allows manufacturers to determine the proper balance of the unique 
emissions challenges of a diesel or gasoline vehicle.

                                             Table IV--17 2010/11 Certification Test Results at 4,000 Miles
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               NMHC            NMOG             NOX             CO           NMOG+NOX
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gasoline..................................  Class 2b....................           0.050           0.052           0.041           1.648           0.092
                                            Class 3.....................           0.080           0.083           0.073           2.373           0.156
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                             NMHC+NOX
--------------------------------------------------------------------------------------------------------------------------------------------------------
Diesel....................................  Class 2b....................           0.037  ..............           0.138           0.195           0.174
                                            Class 3.....................           0.019  ..............           0.249           0.158           0.268
-------------------------------------------------------------------------
Combined Class 2b.......................................................           0.043           0.026           0.089           0.922           0.133
Combined Class 3........................................................           0.050           0.041           0.161           1.265           0.212
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Manufacturers typically certify their vehicles at emissions levels 
well below the numerical standards. This difference is referred to as 
``compliance margin'' and is a result of manufacturers' efforts to 
address all the sources of variability that could occur during the 
certification or in-use testing processes and during in-use operation. 
These sources of variability include: Test-to-test variability, test 
location, build variation and manufacturing tolerances, vehicle 
operation (for example: Driving habits, ambient temperature, etc.), and 
the deleterious effects of sulfur and other oil and fuel contaminants. 
To meet the NMOG+NOX standard of 178 mg/mi for Class 2b and 
247 mg/mi for Class 3 vehicles and establish a compliance margin for 
these sources of variability, manufacturers will need to reduce their

[[Page 23490]]

emission levels considerably from the levels indicated in this data 
set, particularly for diesel vehicles.
    However, as discussed above, these emission results do not include 
the expected emissions deterioration which will be determined by 
manufacturers during development and certification testing. Therefore, 
manufacturers will need to further reduce emissions levels in 
anticipation of the unavoidable emissions deterioration that will occur 
during the useful life of the vehicle. Further, deterioration is a 
function of several factors, but it is predominantly due to emissions 
control hardware thermal exposure (high temperatures), which is 
typically a significant issue on vehicles used for performing work like 
Class 2b and 3 vehicles.
    We also expect that the 2011 heavy-duty GHG rule will present new 
challenges to manufacturers' emissions performance goals as vehicles 
begin to use new engines designed to meet the new GHG 
requirements.\341\ Some of these new technologies may result in 
emissions challenges that are specific to certain operating conditions. 
For example, downsized gasoline engines will likely have improved FTP 
exhaust emissions but have increased challenge with the high-load SFTP 
requirements. Diesel-fueled vehicles may need to carefully balance 
engine controls which reduce GHG emissions but can increase criteria 
emissions (NOX).
---------------------------------------------------------------------------

    \341\ 76 FR 57106 (September 15, 2011).
---------------------------------------------------------------------------

    With regard to the ability of the heavy-duty fleet to meet the PM 
standards for the FTP and the SFTP, we based our conclusions on some 
testing of current heavy-duty gasoline vehicles (HDGVs) and the PM 
performance of the existing light-duty fleet with similar engines. 
Testing of two HDGVs with the highest sales volume (Ford F250 and 
Chevrolet Silverado 2500), albeit not aged to full useful life, 
confirmed that they have similar PM emissions levels as the light-duty 
counterparts and therefore also meet the standards for both the Class 
2b and Class 3 configurations. Data from light-duty gasoline vehicles 
with similar or common engines with their heavy-duty ``sister'' vehicle 
models demonstrates that these vehicles are currently meeting the Tier 
3 FTP PM standards at the Tier 2 useful life mileage of 120,000 miles. 
Heavy-duty diesel vehicles all are equipped with DPFs and have no 
challenges meeting the FTP or SFTP PM standards being set for Tier 3.
    The SFTP test data from the same two heavy-duty vehicles described 
above indicates that gasoline vehicles can achieve the standards for 
SFTP NMOG+NOX and PM. Since heavy-duty vehicles are not 
currently required to comply with any of the SFTP requirements, 
manufacturers have not focused on improving the emissions performance 
specifically over the SFTP cycles (US06, LA-92, and SC03). Therefore, 
although the limited testing results had a high degree of variability, 
several tests met the PM standards for the high power-to-weight Class 
2b vehicles. Consistent with light-duty, vehicles that are 
demonstrating high PM on the US06 will need to control enrichment and 
oil consumption from engine wear. Recently manufacturers have already 
been implementing product changes to reduce oil consumption to address 
both customer satisfaction issues and to reduce cost of vehicle 
ownership.
    Given the technologies likely to be applied to meet the HDV exhaust 
emissions standards, discussed below, we consider the lead time 
available before the standards take effect under all of the 
alternatives to be sufficient. HDV manufacturers are already adopting 
some of the complying technologies, especially for their light-duty 
vehicles, and these can readily be adapted for heavy-duty applications. 
In addition, manufacturers have already begun developing these 
technologies for HDVs, including diesels, in response to California's 
recently adopted LEV III MDV standards which begin to take effect in 
the 2015 model year. Finally, as described above in Sections IV.B.2, 
IV.B.3, and IV.B.4, our program incorporates a number of phase-in and 
alternative compliance provisions that will ease the transition to 
final standards without disrupting heavy-duty pickup and van product 
redesign cycles. Among these is an alternative phase-in that does not 
begin mandatory standards until model year 2019.
    Comments we received on the proposed HDV standards did not 
specifically address our analysis of their technical feasibility. The 
Manufacturers of Emission Controls Association (MECA) outlined diesel 
and gasoline-engine technologies that they expect will be used to 
achieve the Tier 3 standards cost-effectively, generally consistent 
with our draft RIA. Vehicle and engine industry commenters argued that 
the case we made for feasibility relied too heavily on extending light-
duty truck test data, supplemented by testing of only two HDVs, neither 
of which were fully aged or representative of future vehicles designed 
to meet our new GHG standards. However, commenters did not question the 
feasibility, durability, implementability, or effectiveness of the 
technologies we identified, or their ability to achieve the proposed 
standards. Instead, the focus of these comments was on statutory 
provisions for lead time and stability, and on how relaxed standards 
for in-use testing and testing at high altitudes would help to 
implement the standards within the allotted lead time. These issues, 
including changes we are making in response to the comments, are 
addressed in Sections IV.B.2.c, IV.B.6.a, and IV.B.6.f.
i. Technologies Likely To Be Applied
    The technologies expected to be applied to vehicles to meet the 
lower standards levels will address the emissions control system's 
ability to control emissions during cold start. Current vehicle 
emissions control systems depend on the time it takes for the catalyst 
to light-off, which is typically defined as the catalyst reaching a 
temperature of 250 [deg]C. While the specific emissions challenge is 
somewhat different for gasoline engines than for diesel engines, 
achieving the necessary temperatures in the catalysts is a common 
challenge. In order to improve catalyst light-off, the manufacturers 
will likely add technologies that provide heat from combustion more 
readily to the catalyst or improve the catalyst efficiency at lower 
temperatures. These technologies could include calibration changes, 
thermal management, close-coupled catalysts, catalyst Platinum Group 
Metal (PGM) loading, and possibly secondary air injection. In some 
cases, where the catalyst light-off response and efficiency are not 
enough to address the cold start emissions, hydrocarbon adsorbers may 
be applied to trap hydrocarbons until such time that the catalyst is 
lit-off. Note that with the exception of hydrocarbon adsorbers each of 
these technologies addresses both NMOG and NOX performance. 
Key potential technologies are described in greater detail below.
     Engine Control Calibration Changes--These include changes 
to retard spark and/or adjust air/fuel mixtures such that more 
combustion heat is created during the cold start on gasoline engines. 
Diesel engines may use unique injection timing strategies or other 
available engine control parameters. Engine calibration changes can 
affect NMOG, NOX and PM emissions.
     Thermal Management--This technology includes all design 
attributes meant to conduct the combustion heat into the catalyst with 
minimal cooling on both gasoline and diesel engines. This includes 
insulating the exhaust piping between the engine and the catalyst, 
reducing the wetted area of the

[[Page 23491]]

exhaust path and/or reducing the thermal mass of the exhaust system. 
Close-coupling of catalysts (packaging the catalysts as close to the 
head of the engine as possible to mitigate the cooling effects of 
longer exhaust piping) can also be effective, but is more difficult to 
employ than in light-duty applications because of durability concerns 
with highly loaded operation and the potential increase in fuel 
consumption to protect the catalyst from high temperatures.
     Catalyst PGM Loading--Additional PGM loading in the 
catalyst provides a greater number of sites to catalyze emissions and 
addresses NMOG, NOX and PM emissions.
     Selective Catalytic Reduction Optimization--Diesel 
applications will continue to refine this NOX emissions 
control strategy through improved hardware design and implementation in 
vehicle applications. Additional engineering enhancements in the 
control of the SCR system and related processes will also help reduce 
emissions levels.
6. Other HDV Provisions
a. In-Use Emissions
    The proposal requested comment on the need for relaxation of 
NMOG+NOX and PM standards for in-use vehicle testing. The 
LEV III program includes these on an interim basis in the more 
stringent bins in both FTP and SFTP testing. However, in its written 
comments, CARB expressed the view that the technologies required for 
SFTP compliance are well-established, and that sufficient lead time is 
provided such that interim in-use standards for SFTP are not needed. As 
a result, CARB expressed an intent to propose aligning the LEV III 
program with the approach EPA proposed on this matter after the Tier 3 
program is finalized. The manufacturers commented that relaxed interim 
in-use standards are needed in the HDV sector, both for FTP and SFTP 
standards. The reasons cited were a need to harmonize with LEV III, the 
scarcity of data on which to establish standards that apply over the 
full useful life, the extension of that useful life to 150,000 miles, 
the need for manufacturers to address customer concerns with new 
products and technologies, uncertainties that accompany the new SFTP 
cycles and part 1066 testing requirements (especially for PM), and the 
introduction of innovative technologies required to meet GHG standards 
in the same timeframe.
    After considering the comments we have concluded that relaxed 
interim in-use standards are appropriate for HDVs, both for FTP and 
SFTP testing. We are adopting HDV in-use standards levels that are 
identical to those adopted for LEV III, as shown in Table IV-18. We 
consider these levels reasonable, in line with relaxed in-use standards 
adopted in past programs, and helpful toward harmonization. We are not 
applying interim in-use NMOG+NOX standards to the interim 
(two highest) bins for the FTP standards, because these bins are 
intended for carry-over of existing designs, and there should be little 
uncertainty over their in-use emissions performance. Interim bin 
vehicles certified to the Tier 3 PM standards shall, however, be 
subject to the relaxed in-use PM standards in the same way as for HDVs 
in other bins. Bin 0 standards are driven by specific zero-emissions 
technologies for which in-use margins would not be appropriate, and so 
we are not setting in-use standards for Bin 0.
    We are also adopting the general approach taken in LEV III of 
making these interim standards available during the phase-in period 
(model years 2016-2022) for the first two model years that a test group 
is newly certified to a Tier 3 NMOG+NOX or PM standard. Test 
groups subsequently recertified to a more stringent NMOG+NOX 
bin standard may begin the two year cycle over again. A test group that 
is first certified into a Tier 3 bin in model year 2022 or later may 
not take advantage of the relaxed interim in-use standards. LEV III 
adopted somewhat different applicability years, for the most part 
ending earlier, in model year 2020. However, we believe that the modest 
extension is appropriate to facilitate the Tier 3 phase-in. If a 
vehicle test group is certified into a Tier 3 bin, but not yet to the 
Tier 3 PM standard, the in-use standard for PM shall apply for the 
first two model years it is first certified to the PM standard. In 
order to better harmonize with LEV III, the availability of these in-
use standards includes the voluntary model years.

                                 Table IV-18--Interim In-Use Standards for HDVs
----------------------------------------------------------------------------------------------------------------
                                                      FTP (mg/mi)                        SFTP (mg/mi)
                                         -----------------------------------------------------------------------
                                              NMOG+NOX             PM             NMOG+NOX             PM
----------------------------------------------------------------------------------------------------------------
                                                    Class 2b
----------------------------------------------------------------------------------------------------------------
Bin 395 (interim).......................             (\a\)                16             (\a\)             (\a\)
Bin 340 (interim).......................             (\a\)                16             (\a\)             (\a\)
Bin 250.................................               370                16      \b\ 770/1120         \b\ 12/15
Bin 200.................................               300                16      \b\ 770/1120         \b\ 12/15
Bin 170.................................               250                16       \b\ 490/630         \b\ 12/15
Bin 150.................................               220                16       \b\ 490/630         \b\ 12/15
Bin 0...................................             (\a\)             (\a\)             (\a\)             (\a\)
----------------------------------------------------------------------------------------------------------------
                                                     Class 3
----------------------------------------------------------------------------------------------------------------
Bin 630 (interim).......................             (\a\)                20             (\a\)             (\a\)
Bin 570 (interim).......................             (\a\)                20             (\a\)             (\a\)
Bin 400.................................               600                20               770                12
Bin 270.................................               400                20               770                12
Bin 230.................................               340                20               490                12
Bin 200.................................               300                20               490                12
Bin 0...................................             (\a\)             (\a\)             (\a\)             (\a\)
----------------------------------------------------------------------------------------------------------------
\a\ No relaxed interim in-use standard.
\b\ The lower value applies to low power-to-weight vehicles optionally certified using only the highway portion
  of the SFTP US06.


[[Page 23492]]

b. HDV Useful Life
    Currently the HDV regulatory useful life, the period of use or time 
during which emissions standards apply, is 120,000 miles or 11 years, 
whichever occurs first (40 CFR 86.1805-4). For Tier 3 vehicle criteria 
emissions we are extending the useful life to 150,000 miles or 15 
years, whichever occurs first. This change better reflects the 
improvements in vehicle durability and longevity that have occurred in 
the several years since the 120,000 mile useful life was established, 
and maintains consistency with the LEV III MDV program and with our 
Tier 3 program for large LDTs, for which the same useful life period is 
being adopted.
    The new useful life requirement applies to Tier 3 HDVs in all bins 
except those designated as interim bins, consistent with the purpose of 
the interim bins to provide for limited carry-over of pre-Tier 3 
vehicle designs during the phase-in period. Although the percentage 
application in each year will therefore depend on each manufacturer's 
fleet binning strategy, the declining NMOG+NOX fleet average 
standard will ensure a robust phase-in of the new useful life 
requirement over the 2018-2022 model years, such that it is expected to 
be about 50 percent in 2018, and necessarily reaches 100 percent by 
2022 when the interim bins are no longer available. For those 
manufacturers choosing to certify to the voluntary standards, the new 
useful life will apply even earlier, in model year 2016 or 2017. For 
manufacturers choosing the alternative percent-of-sales 
NMOG+NOX alternative, the new useful life requirement 
applies to all HDVs counted toward the phase-in requirement, resulting 
in a generally equivalent useful life phase-in rate to that of the LEV 
III-harmonized alternative.
    See Section IV.F.5 for further discussion of useful life 
requirements with regard to GHG standards. Manufacturers may optionally 
retain the 120,000 mile/11 year useful life for PM on interim Tier 3 
vehicles that are not phased in to the Tier 3 PM standards. We received 
no adverse comments on these useful life provisions.
c. Heavy-Duty Alternative Fuel Vehicles
    As in the light-duty program, manufacturers must demonstrate heavy-
duty flexible fuel vehicle (FFV) and dual-fuel vehicle compliance with 
both the FTP and the SFTP emissions standards when operating on both 
the conventional petroleum-derived fuel and the alternative fuel. 
Dedicated alternative fuel vehicles must demonstrate compliance with 
both the FTP and SFTP emission standards while operating on the 
alternative fuel. For all of these vehicles, this includes the 
requirement to meet FTP emissions standards when conducting fuel 
consumption and GHG emissions testing, and also to meet the FTP and 
highway test requirements at high altitudes (see Sections IV.B.6.e and 
f). Because FFVs can operate on various combinations of their 
conventional and alternative fuel, the emissions requirements apply to 
operation at any mix of the fuels achievable in the fuel tank with 
commercially available fuels, including for compliance at high 
altitudes, even though the required demonstration of compliance is 
limited to the conventional and alternative fuels designated for 
certification testing. We received no adverse comments on these 
provisions.
d. Existing Provision To Waive HDV PM Testing
    EPA's existing program includes a provision for manufacturers to 
waive measurement of PM emissions in non-diesel heavy-duty vehicle 
emissions testing. As proposed, we are eliminating this provision. We 
believe that the Tier 3 PM standards for these vehicles are of 
sufficient stringency that routine waiver of testing is not 
appropriate. The CARB LEV III program also reflects this view. We do 
not expect this change to be onerous for manufacturers, as the number 
of heavy-duty vehicle families is not large. We received no adverse 
comments on this change.
e. Meeting HDV Standards in Fuel Consumption and GHG Emissions Testing
    As with the light-duty Tier 3 program, HDVs must meet the FTP bin 
standards when tested over both the city and highway test cycles. We do 
not believe this adds a very significant test burden as vehicle 
emissions are already required to be measured when these tests are run 
for GHG and fuel consumption determinations. Nor do we believe that 
this requirement is design forcing. Rather, we are creating this 
requirement to ensure that test vehicle calibrations are not set by 
manufacturers to minimize fuel consumption and GHG emissions, at the 
expense of causing high criteria pollutant emissions. Considering the 
additional work involved in measuring PM emissions and the reduced 
likelihood of high PM emissions on the highway test, we are not 
mandating that PM emissions testing be included in this requirement. We 
received no adverse comments on these proposed provisions.
f. HDV Altitude Requirements
    As in the past, we intend that HDV Tier 3 standards result in 
emissions controls that are effective over a full range of operating 
altitudes. We proposed that HDVs be required to meet the FTP bin 
standards (but not the SFTP standards) at high altitudes, and expressed 
our expectation that compliance with the FTP standards would require 
neither the use of special hardware nor adjustment to the level of the 
standards.
    The manufacturers argued in their comments that the reasons EPA 
cited in proposing relief at high altitudes for light-duty vehicles 
apply for HDVs as well, and requested that relaxed NMOG+NOX 
standards be adopted in the more stringent bins for testing of HDVs at 
high altitudes. Ford argued that the challenges could be even greater 
for HDVs because they are designed to operate at high altitudes with 
heavy payloads and towed trailers, and this may necessitate the 
locating of emissions systems farther from exhaust manifolds, thereby 
increasing catalyst lightoff delays.
    Although we agree to a certain extent about the performance of 
gasoline-fueled HDVs at high altitudes and their similarity to LDVs, 
the comments did not alter our view that the compliance margins 
provided in the HDV FTP bin standards compared to what the control 
technologies can achieve, and the freedom manufacturers have to shift 
to the more stringent bins gradually as the program phases in, are 
adequate to account for these effects at altitude. The manufacturers 
provided no data to counter this view.
    We note that our adoption of relaxed interim in-use standards for 
vehicles in these bins will be directionally helpful to address any 
remaining concerns by manufacturers regarding emissions at altitude 
(Section IV.B.6.a). This is because testing at high altitudes is often 
not required for certification (typically manufacturers use an 
engineering analysis instead), and thus the relaxed in-use standards 
will help to facilitate Tier 3 implementation for any HDV designs in 
which in-use problems at high altitudes surface in the initial model 
years.

C. Evaporative Emissions Standards

    Gasoline vapor emissions from vehicle fuel systems, which are a 
mixture of hydrocarbon compounds, occur when a vehicle is in operation, 
when it is parked, and when it is being refueled. Evaporative emissions 
which occur daily from gasoline-powered vehicles are primarily 
functions of air

[[Page 23493]]

and fuel temperature, fuel vapor pressure, and vehicle driving. EPA 
first instituted evaporative emissions standards in the early 1970s to 
address hydrocarbon emissions when vehicles are parked after being 
driven. These are commonly referred to as hot soak and diurnal 
emissions. Over the subsequent years the test procedures have been 
modified and improved, the standards have been revised to be more 
stringent, and we have addressed emissions which arose from new fuel 
system designs by establishing new requirements such as running loss 
emission standards and test procedure provisions which address resting 
losses (e.g., permeation). Onboard refueling vapor recovery (ORVR) 
requirements for control of refueling emissions first began to phase-in 
for light-duty vehicles (LDVs) and light-duty trucks (LDTs) in the 1998 
MY. These were later expanded to cover medium-duty passenger vehicles 
(MDPVs) and some heavy-duty gasoline vehicles (HDGVs).
    Even though evaporative and refueling emission control systems have 
been in place for most of these vehicles for many years, evaporative 
emissions still contribute 30-40 percent of the on-road mobile source 
hydrocarbon inventory. The rate of these emissions in grams/day (hot 
soak and diurnal), grams/mile (running loss) or grams per gallon 
(refueling) depends on (1) the stringency of the applicable emission 
standards, (2) ambient and fuel temperature, (3) fuel vapor pressure, 
and (4) the presence/state of repair of the fuel/evaporative control 
system.
    These fuel vapor emissions are ozone and PM precursors, and also 
contain air toxics such as benzene. Even though there are mature 
evaporative emission control programs in place, further hydrocarbon 
emission reductions are needed and can be achieved from further 
evaporative emission controls on gasoline-powered highway motor 
vehicles.
    This section discusses the vehicle evaporative emission standards 
and related provisions for LDVs, LDTs, MDPVs, and HDGVs. The 
evaporative emissions program has six basic elements: (1) The early 
allowance program (MY 2015-2016), (2) the transitional program (MY 
2017), (3) the Tier 3 evaporative emission phase-in program (MY 2018-
2021), (4) the fully phased-in standards (MY2022+), (5) requirements 
for HDGVs including ORVR for the 2018MY, and (6) a leak standard and 
test procedure which become mandatory for Tier 3 vehicles in the 
2018MY. As discussed below, we are finalizing more stringent standards 
that will apply for the 2- and 3-day evaporative emissions tests, a 
canister bleed test procedure and emission standard, and a new 
certification test fuel specification.\342\ As discussed in section 
IV.D, we are also adding a fuel/vapor system leak standard and test 
procedure for LDVs, LDTs, and MDPVs. EPA is not changing any existing 
light-duty running loss or refueling emission standards with the Tier 3 
FRM, with the exception of the certification test fuel specification 
and the addition of a refueling emission controls for complete HDGVs 
over 10,000 lbs gross vehicle weight rating (GVWR). This section also 
describes phase-in flexibilities, credit and allowance programs, and 
other issues related to evaporative emissions control.
---------------------------------------------------------------------------

    \342\ Certification fuel provisions for evaporative and 
refueling emissions testing for flexible fuel vehicles (FFVs) are 
discussed separately below.
---------------------------------------------------------------------------

    In this rule, the vehicle classifications, LDVs, LDTs, MDPVs, and 
HDGVs, remain unchanged from Tier 2 (see 40 CFR 86.1803-010). For 
purposes of this discussion of the Tier 3 evaporative emissions 
program, the vehicle standards can be further placed in four 
categories: (1) ``zero evaporative emission'' PZEV vehicles certified 
by CARB as part of the ZEV program, (2) vehicles certified by CARB to 
meet LEV III evaporative emission program requirements on CARB 
certification fuel (7 RVP E10) as early as 2014 MY, (3) vehicles 
meeting the Tier 3 evaporative emissions program requirements using the 
Tier 3 certification test fuel (9 RVP E10), and (4) transitional 
vehicles meeting existing EPA evaporative requirements on Tier 2 
certification test fuel (9 RVP E0).343 344 For ease of 
reference these four categories may be referred to as PZEV evap, LEV 
III evap, Tier 3 evap, and Tier 2/MSAT evap in this section.\345\
---------------------------------------------------------------------------

    \343\ We adopted the most recent vehicle evaporative emission 
standards for LDVs, LDTs, and MDPVs in 2007 (72 FR 8428, February 
26, 2007). The most recent standards for HDGVs were adopted in 2000 
(66 FR 5165, January 18, 2001).
    \344\ See Section IV.F for a discussion of the final 
certification fuel provisions, including discussion of options for 
and implications of the certification test fuel having 10 percent 
ethanol.
    \345\ ``PZEV evap'' as discussed here refers only to the 
evaporative emission and useful life requirements of the PZEV 
program, not the exhaust emission requirements.
---------------------------------------------------------------------------

1. Tier 3 Evaporative Emission Standards
a. Final Standards
    The Tier 3 program for evaporative emissions builds on previous EPA 
requirements as well as the evaporative emissions portion of CARB's 
recent LEV III rule which starts mandatory phase-in with the 2018 MY. 
The level of the standards, the timing of their implementation, and 
related provisions are designed in great measure to allow manufacturers 
to design, certify, and build one control system for each evaporative/
refueling family to meet CARB and EPA requirements so that these 
vehicles can be sold in all 50 states. Commenters supported this 
approach and no commenter opposed the stringency or timing of the 
evaporative emission standards and related test procedures. We believe 
the program is appropriate since it will require new more stringent 
evaporative emissions control technology in new vehicles and also 
achieve improved in-use system performance.
    Section IV.C.1.a.i, which follows, describes the basic emission 
standard levels for LDVs, LDTs, MDPVs, and HDGVs. Section IV.C.1.a.ii, 
describes a new canister bleed standard and testing requirement for 
measuring emissions from the evaporative canister. Section IV.C.1.a.iii 
discusses the optional use of the CARB LEV III Option 1 evaporative 
emission standards during a transition period. Next, Section 
IV.C.1.a.iv discusses interim use of CARB PZEV zero evap data based on 
CARB Phase II fuel. Finally section IV.C.1.a.iv, discusses the ongoing 
requirement to meet running loss emission standards.
i. Hot Soak Plus Diurnal Standards
    The Tier 3 hot soak plus diurnal emission standards are designed to 
bring into the broader motor vehicle fleet the ``zero evap'' technology 
used by the manufacturers in their partial zero emission vehicles 
(PZEVs). Manufacturers developed this ``zero evap'' technology as part 
of their response to meeting the requirements of the CARB Zero Emission 
Vehicle (ZEV) program. This program, which is in effect in 11 other 
states, allows manufacturers to meet their ZEV mandate percentages 
(totally or in-part) by the use of vehicles which among other 
characteristics have very low fuel vapor emissions.
    The hot soak plus diurnal emission standards we are adopting 
(presented in Table IV-19) are designed to be met with technology that 
limits Tier 3 vehicles to essentially zero fuel vapor emissions. For 
the Tier 3 evaporative emissions program, we are not changing the basic 
2-and 3-day evaporative emission test procedures other than the 
certification fuel requirements. The level of the standards primarily 
accommodates what is often referred to as new vehicle background 
hydrocarbon emissions. These emissions arise from the off-gassing of 
volatile hydrocarbons from plastics, rubbers, and other

[[Page 23494]]

polymers found in new vehicles (e.g., new tires, interiors, seats, fuel 
system components, paints, and adhesives). In the field these emissions 
decrease over time as the vehicle ages, but this cannot necessarily be 
replicated in the time that manufacturers typically allocate for 
vehicle certification or with the techniques normally used for vehicle 
pre-conditioning. Provisions related to vehicle pre-conditioning before 
evaporative emissions certification testing are discussed further 
below.
    In the past EPA has set relatively uniform (but not identical) 
evaporative emission standards for LDVs and LDTs and somewhat higher 
values for MDPVs and HDGVs. The Tier 3 hot soak plus diurnal emission 
standards follow this approach, because in general the vehicles have 
higher levels of non-fuel background emissions as they get larger.
    As described in more detail in Section IV.C.2.d below, EPA is 
finalizing a program that will allow manufacturers to demonstrate 
compliance with the hot soak plus diurnal evaporative emission 
standards using averaging concepts. A manufacturer may comply by 
averaging within each of the four vehicle categories but for the 
reasons discussed below, may not rely on averaging across categories. 
The technical approaches to meeting the standards are discussed in 
Section IV.C.2.

            Table IV-19 Final Evaporative Emission Standards
                          [g/test] \a\ \b\ \c\
------------------------------------------------------------------------
                                                    Highest hot soak +
                                                   diurnal level (over
        Vehicle category/averaging sets            both 2-day and 3-day
                                                      diurnal tests)
------------------------------------------------------------------------
LDV, LDT1......................................                    0.300
LDT2...........................................                    0.400
LDT3, LDT4, MDPV...............................                    0.500
HDGVs..........................................                    0.600
------------------------------------------------------------------------
\a\ The standards are in grams of hydrocarbons as measured by flame
  ionization detector during the diurnal and hot soak emission tests in
  the enclosure known as the sealed housing for evaporative
  determination (SHED).
\b\ Note that the standards are the same for both tests; existing
  standards are slightly different for the 2- and 3-day tests.
\c\ Vehicle categories are the same as in EPA's Tier 2 final rule; see
  65 FR 6698, February 10, 2000.

ii. Canister Bleed Emission Standard
    In addition to more stringent hot soak plus diurnal standards, EPA 
is finalizing a new canister bleed emission test procedure and standard 
as part of the Tier 3 program. The canister bleed test procedure is 
described in Section IV.C.6 below. EPA is adopting the canister bleed 
standard because it is an important tool in moving Tier 3 evaporative 
emissions control toward zero fuel vapor emissions. No commenter 
opposed the canister bleed standard or commented on the test procedure. 
The new test and standard align with the California LEV III 
requirements and help to ensure that near-zero fuel vapor emissions are 
being emitted by vehicles from the fuel tank through the evaporative 
emission canister. Manufacturers will be required to measure diurnal 
emissions over the 2-day diurnal test procedure from just the fuel tank 
and the evaporative emission canister using Tier 3 certification fuel 
and comply with a 0.020 g/test standard for all LDVs, LDTs, and MDPVs 
and 0.030 g/test for HDGVs. The feasibility of this standard is 
discussed in Section IV.C.3 below. The canister bleed test and standard 
drives canister design elements such as total gasoline working 
capacity, internal architecture, and the type of carbon used. These are 
also key elements of canister design for the hot soak plus diurnal 
emission standards.
    The canister bleed standard will be implemented differently than 
the hot soak plus diurnal standard. EPA is not applying the averaging 
program to this new bleed test standard as compliance is relatively 
straightforward and low in cost. Therefore, each evaporative/refueling 
emission family certified by manufacturers will need to demonstrate 
compliance with their respective standard. As discussed below, the 
canister bleed standard will not apply at high altitude, but 
proportional control is expected. Since the performance of the canister 
is also evaluated in the hot soak plus diurnal evaporative emissions 
sealed housing for evaporative determination (SHED) test the canister 
bleed emission standard will not be included in the In-Use Verification 
Program of under 40 CFR 86.1845 through 1853, but it must be met in 
use. We will not have canister bleed specific family criteria for 
certification but the test will have to be completed and the standard 
met for each evaporative/refueling family including potentially twice 
if there are two canisters used. A deterioration factor will not be 
required, but the manufacturer must certify that the standard will be 
met for the full useful life. As mentioned above, the standard will 
have to be met in-use and could be evaluated in EPA confirmatory 
testing.
    The canister bleed standard will have to be met using the same 
fuels and test procedures used for the hot soak plus diurnal standards. 
We will accept results on either CARB or EPA test fuels/test 
temperatures for the canister bleed test provided the same are used for 
the hot soak plus diurnal test.
iii. Hot Soak Plus Diurnal Standard With the Fuel System Rig Test
    As part of its LEV III program, CARB has included an alternative 
set of evaporative emission standards, referred to as Option 1 
standards. These are shown in Table IV-20.

                            Table IV-20 CARB--Option 1 Evaporative Emission Standards
----------------------------------------------------------------------------------------------------------------
                                                             Highest hot soak + diurnal level
                                                              (over both 2- and 3-day diurnal
                     Vehicle category                                tests)  (g/test)           Running loss (g/
                                                           ------------------------------------       mile)
                                                              Vehicle SHED        Rig SHED
----------------------------------------------------------------------------------------------------------------
Passenger Car.............................................             0.350               0.0              0.05
LDT <= 6,000 lbs GVWR.....................................             0.500               0.0              0.05
All other vehicles > 6,000 lbs GVWR.......................             0.750               0.0              0.05
----------------------------------------------------------------------------------------------------------------


[[Page 23495]]

    The Option 1 standards include evaporative emission standards (hot 
soak plus diurnal) that are slightly higher numerically than our final 
standards. Vehicles certified under this option may not use averaging 
in the CARB LEV III program because they basically represent the same 
evaporative emission standards as exist for PZEVs under CARBs ZEV 
program wherein averaging is not permitted. Option 1 also includes an 
additional SHED test of the vehicle fuel system (rig test) that pre-
dates development of the canister bleed emission standard. The rig SHED 
test is discussed in Section IV.C.6. From a practical perspective, this 
test is more difficult to conduct than the bleed test discussed above 
and is intended to force manufacturers to demonstrate at certification 
that their stand alone (not in chassis) fuel/vapor control system 
designs have <= 54 mg fuel vapor emissions.\346\ While one commenter 
was in favor of permanently including Option 1 in the EPA final rule 
based on what it viewed to be favorable pre-production engineering 
design features of the rig SHED test, EPA is including Option 1 only as 
interim compliance alternative for a limited period of time but not as 
a permanent option in the Tier 3 evaporative emission program. While we 
see the value to vehicle manufacturers of the rig SHED test as an 
engineering design and development tool, by its very nature, the rig 
SHED test and standard is not implementable as an enforceable standard 
because a fuel system cannot be removed from a vehicle and 
reconstructed in a SHED for testing without compromising its 
fundamental structural and mechanical integrity as it existed on the 
vehicle. We believe that the hot soak plus diurnal SHED test and 
standard and the canister bleed test and standard will accomplish the 
objective of keeping fuel vapor emissions to a minimum while doing so 
in an enforceable manner.
---------------------------------------------------------------------------

    \346\ Any value < 54mg rounds down to zero under the 
regulations.
---------------------------------------------------------------------------

    EPA believes most manufacturers will prefer to certify to the 
averaging based standards in Table IV-1 (similar in stringency and 
program construct to CARB Option 2). However, because some 
manufacturers may have vehicle models meeting the CARB Option 1 
standards and emission requirements now or in the near future, EPA will 
allow compliance with the CARB Option 1 standards as an acceptable 
interim alternative to compliance with the Tier 3 evaporative emission 
standards if the model is certified by CARB to LEV III requirements 
before the 2017 MY. These vehicles could then be certified using 
carryover provisions through the 2021 MY as part of the evaporative 
emissions phase-in described below. This is two model years longer than 
in the proposal, but this extension is reasonable given the life cycle 
of most fuel/vapor control systems and the goal of aligning with the 
LEV III program for a national program where possible.\347\ As noted in 
the following sections, vehicles certified under this provision will 
count toward the phase-in percentage requirements and could earn 
allowances as discussed below, but the vehicles will not be eligible to 
earn or use credits for the evaporative emissions averaging program. 
Carryover vehicles will have to meet the EPA leak standard and the high 
altitude emission standard to be counted toward the sales percentage 
requirements for 2018 and later model years.
---------------------------------------------------------------------------

    \347\ EPA is incorporating by reference the CARB Option 1 test 
procedures and emission standards for this interim period.
---------------------------------------------------------------------------

iv. Interim Carryover of PZEV Evap Data for Tier 3 Certification
    To earn credits toward compliance with the CARB Zero Evaporative 
Emissions (ZEV) program requirements, many manufacturers have certified 
LDVs and LDTs to 150,000 mile useful life emission standards similar to 
those found in Table IV-20. These vehicles have used CARB Phase II fuel 
(E0) and met the rig SHED test requirement in lieu of the canister 
bleed standard, but otherwise have employed the same basic technology 
EPA expects for the LEV III and Tier 3 programs. EPA is permitting data 
generated from certification of these vehicles in the 2015 and 2016 MYs 
to be used for Tier 3 evaporative emissions purposes through the 2019 
MY.
v. Running Loss Emission Standards
    EPA has required vehicles to meet running loss emission standards 
since the 1996 model year. These requirements, which are specified in 
40 CFR 86.134-96, apply to all gasoline-powered highway motor vehicles. 
EPA is not changing either the test procedures or emission standard for 
the running loss test. However, the change in certification test fuel 
will apply to testing for such standards. This is appropriate based on 
the rationale for implementing a certification fuel change and is 
necessary since the running loss test is part of the overall test 
sequence for the 3-day hot soak plus diurnal test. EPA does not 
anticipate that the change in certification test fuel will impact the 
stringency of the running loss test and standards or the manufacturers' 
ability to comply as part of Tier 3.
b. High-Altitude Requirements
    Prior to this rule, the most recent vehicle evaporative emission 
standards were adopted in 2007.\348\ The new standards adopted in 2007 
apply only to testing under low-altitude conditions.\349\ In the 2007 
rule, we decided to continue to apply the previous ``Tier 2'' standards 
for testing under high-altitude conditions. This was necessary to 
achieve an equivalent level of overall stringency for high-altitude 
testing, accounting for the various effects of altitude and lower 
atmospheric pressure on vapor generation rates, canister loading and 
purging dynamics, and other aspects of controlling evaporative 
emissions due primarily to lower air density and vapor concentrations 
at altitude. While it is important for vehicles to have effective 
emission controls at high altitudes, we do not want the high-altitude 
standards and test procedures to dictate the fundamental design of the 
Tier 3 evaporative emission control systems since the high altitude 
vehicle population is only about five percent of the national total. 
Therefore, we believe it is appropriate to address this goal by 
applying the current 2-day low altitude evaporative emission standards 
and requirements for high-altitude testing.\350\ The vehicle categories 
for the high altitude standards in this rule are the same as for the 
low altitude standards. The standards are presented below in Table IV-
21. This will both reduce evaporative emissions at high altitude and 
again create a requirement to confirm that emission controls function 
effectively at high altitude without forcing manufacturers to apply 
altitude-specific technologies. The leak standard presented in Section 
IV.D below will apply equally at low and high altitude testing as 
compliance is not dependent on air density and vapor concentrations.
---------------------------------------------------------------------------

    \348\ See 72 FR 8428 (February 26, 2007).
    \349\ Low altitude conditions means a test altitude less than 
549 meters (1,800 feet). High-altitude conditions means a test 
altitude of 1,620 meters (5,315 feet) plus or minus 100 meters (328 
feet) or equivalent observed barometric test conditions of 83.3 kPa 
(24.2 inches Hg) plus or minus 1kPA (0.30 inches Hg) See 40 CFR 
86.1803-01.
    \350\ See Control of Air Pollution from New Motor Vehicles: 
Heavy-Duty Engine and Vehicle Standards and Highway Diesel Fuel 
Sulfur Control Requirements 66 FR 5002, January 18, 2001 and Control 
of Hazardous Air Pollutants from Mobile Sources, 72 FR 8428, 
February 26, 2007.

[[Page 23496]]



     Table IV-21--Final High-Altitude Evaporative Emission Standards
                                [g/test]
------------------------------------------------------------------------
                                                    Highest hot soak +
                                                   diurnal level (over
                Vehicle category                   both 2-day and 3-day
                                                     tests) (g/test)
------------------------------------------------------------------------
LDV, LDT1......................................                     0.65
LDT2...........................................                     0.85
LDT3, LDT4.....................................                     1.15
MDPV...........................................                     1.25
HDGVs <= 14,000 lbs GVWR.......................                     1.75
HDGVs > 14,000 lbs GVWR........................                      2.3
------------------------------------------------------------------------

    A few additional points should be noted about our Tier 3 high 
altitude evaporative emissions control program. First, EPA does not 
expect manufacturers to produce vehicles with high-altitude only 
evaporative control systems. Given the nature of evaporative emission 
control technology, there should be emission reductions at high 
altitude proportional to those achieved at lower altitudes. We are not 
applying the canister bleed test and emission standard at high 
altitude, but we expect similar emission reductions to those which will 
occur at low altitude. These vehicles will have to meet the canister 
bleed emission standard at low altitude and canister bleed emission 
reductions at high altitude should be proportional as is the case with 
the low altitude hot soak plus diurnal standards. Any adjustment to 
meet the standard at high altitude to account for canister adsorption 
and desorption effects of higher altitudes would result in 
fundamentally the same technology with an increase in the testing 
burden but not necessarily more emissions control. Therefore, we 
believe the low-altitude canister bleed test is sufficient for 
achieving the level of emission control for operation in both low-
altitude and high-altitude conditions. Second, for vehicles certified 
with FELs above or below the applicable standard for testing at low 
altitude, the same differential will apply to the FELs for high-
altitude. For example, if an LDV was certified with an FEL of 0.400 g 
instead of the 0.300 g standard, the high-altitude FEL will be 0.75 g 
(0.65g+0.10g). This high-altitude FEL will not be used for any 
emission-credit calculations, but it will be used as the emission 
standard for compliance purposes. Third, gasoline RVP for certification 
test fuel will be set at 7.8 RVP with 10 percent ethanol, as specified 
in Section IV.F. Finally, we are finalizing a minor adjustment to the 
high altitude test procedures. The existing 2- and 3-day test 
procedures apply equally at low and high altitude. We are keeping the 
same basic requirement but will allow for a downward adjustment of 
5[emsp14][deg]F in the temperatures related to the running loss test 
within the 3-day test cycle. Thus, the applicable ambient temperatures 
at Sec.  86.134-96 (f) and (g) will be 905[emsp14][deg]F 
instead of 955[emsp14][deg]F for high altitude testing, and 
the entire fuel temperature profile from Sec.  86.129-94(d) shifts down 
by 5[emsp14][deg]F. EPA believes this is appropriate given the 
differences in atmospheric conditions at low versus high altitude and 
will still result in equivalent control of running loss emissions at 
higher altitudes. EPA requested comment on the alternative approach of 
keeping test temperatures the same, but omitting the 3-day test cycle 
for testing at high altitude. This was supported by one set of 
commenters, but at this time EPA does not have the data needed to drop 
such a fundamental test requirement.
    As mentioned above, emission data from vehicles meeting the current 
CARB PZEV zero evap and CARB LEV III Option 1 requirements could be 
used to qualify that vehicle to meet the Tier 3 evaporative emission 
regulations for the 2017-2021 MYs. To qualify for a federal 
certificate, the vehicle will also have to meet the Tier 3 high 
altitude evaporative emission requirements. CARB does not require 
vehicles to meet EPA high altitude requirements, so for these vehicles 
we are giving the manufacturers the option to certify either by 
providing SHED test data or based on an engineering demonstration using 
data and analysis and the application of good engineering judgment. For 
the 2015-2017 MYs, manufacturers can use data based on either Tier 2 or 
Tier 3 test fuel. Beginning in the 2018 model year, for Tier 3 vehicle 
certification to the high altitude standard, the data must be based on 
Tier 3 fuel.
c. Useful Life
    Trends indicate that vehicle lifetimes are increasing. It is 
important that emission control systems be designed to meet 
requirements while vehicles are in use. As discussed in Section IV.A.7 
and IV.B.6 of this preamble, along with the new emission standards, we 
are finalizing a longer useful life of 150,000 miles/15 years, 
whichever comes first, for LDTs up to 6,000 lbs GVWR but over 3,750 lbs 
loaded vehicle weight (LVW) (LDT2s), all LDTs over 6,000 lbs GVWR 
(LDT3/4), MDPVs, and HDGVs. The longer useful life will apply to all 
certifications to the Tier 3 evaporative emission standards (see Table 
IV-19 and Table IV-20 above). For an evaporative/refueling family 
certified to 150,000 miles/15 year useful life for evaporative 
emissions this useful life will also apply to the hot soak plus 
diurnal, running loss, canister bleed, fuel system rig, refueling, 
leak, and high altitude standards. All of these standards impact the 
fuel and vapor control systems and it is technologically consistent to 
require the same useful life for these standards because they all rely 
on the mechanical integrity, durability, and operational performance of 
the same components in the evaporative emissions control system.
    Due to limitations in the CAA, for LDVs and for LDTs up to 6,000 
lbs GVWR and at or below 3,750 lbs LVW (LDT1s), we are keeping the 
current useful life of 120,000 miles/10 years unless, as described in 
Section IV.A.7, a manufacturer elects alternative exhaust emission 
requirements that are associated with 150,000 mile/15 year useful life 
for these vehicles. For manufacturers that select those optional 
standards, the useful life of 150,000 miles/15 years will apply for all 
Tier 3 evaporative emission requirements as listed in the previous 
paragraph.
    During the early, transition, and phase-in program periods and 
until the final year of the allowed phase-in period for the Tier 3 
evaporative emission program (MY 2015-2021) the differences between the 
exhaust and evaporative emission phase-in programs presents the 
possibility that in some cases a manufacturer could certify a model to 
the Tier 3 exhaust requirements (or CARB equivalents) but not 
necessarily to the Tier 3 evaporative emission requirements.\351\ In 
those situations, the final rule provides that a family could have a 
150,000 miles/15 years useful life for exhaust emissions but maintain 
the current useful life for all of the evaporative and refueling 
emission standards since the vehicle does not yet meet Tier 3 
evaporative emission requirements. During the phase-in period, if a 
family is certified to the Tier 3 evaporative emission requirements but 
not yet certified for Tier 3 exhaust emission requirements, then the 
useful life could be 150,000 miles/15 years for evaporative and 
refueling emissions standards but the existing useful life for exhaust 
emissions. However, by the 2022 MY the useful life for all of these

[[Page 23497]]

requirements will be 150,000 miles/15 years for LDT2/3/4s, MDPVs, and 
HDGVs since by that model year all vehicles must be certified using 
Tier 3 certification fuel and test procedures and meet Tier 3 
evaporative emission standards or CARB equivalents.\352\
---------------------------------------------------------------------------

    \351\ By the 2022 MY, all Tier 3 evaporative system emissions 
certifications must use Tier 3 certification test fuel and test 
procedures or equivalent CARB test procedures, certification and 
emission standards. This affects evaporative (hot soak plus 
diurnal), running loss, and canister bleed emission standards 
certification. Refueling, spit back and leak standards are only to 
be met using Federal certification test fuel.
    \352\ The only exception here will be for vehicles not meeting 
Tier 3 evaporative emission requirements in the 2022 MY as a result 
of the use of previously earned allowances.
---------------------------------------------------------------------------

    OBD regulations call for the systems to operate effectively over 
the useful life of the vehicle. We are not changing that requirement, 
but rather want to clarify that during the early, transition, and 
phase-in years of the program (MY 2015-2021), all of the OBD monitoring 
requirements have the same useful life as that for the exhaust emission 
standard except for the evaporative system leak monitoring requirement 
which has the same as that required for the evaporative and refueling 
emission standards control systems.
d. What requirements must a vehicle meet to qualify as a Tier 3 vehicle 
for evaporative emissions?
    As mentioned above, there are three different revised or new 
evaporative emision requirements applicable to Tier 3 vehicles. These 
are the hot soak plus diurnal standards, the canister bleed standard, 
and the leak standard. In addition the refueling, running loss, and 
spit back standards are unchanged but will have to be met on Tier 3 
certification fuel. Compliance with these requirements is potentially 
complicated by the fact that the CARB ZEV and LEVIII programs will 
bring zero evap technology into the market place before or at the same 
time that Tier 3 implementation begins but with test fuel and test 
procedure differences. In order to qualify as a Tier 3 vehicle for 
evaporative emission purposes the vehicle must meet all applicable 
requirements on the specified fuel. Unless otherwise specified (e.g., 
HDGV refueling spit back), if a vehicle does not meet all evaporative 
emission program requirements, including both the applicable standards 
and test fuel then it does not qualify as a Tier 3 vehicle for 
evaporative emission purposes. Table IV-22, below summarizes the 
requirements that vehicles in various categories must meet to qualify 
as a Tier 3 vehicle for evaporative emission purposes as a function of 
model year. The entries in the cells of the table specify the required 
test fuel. The table is for reference of the reader in reviewing 
subsequent sections of this preamble. Refer to the regulatory text for 
specific requirements for the various programs.

                  Table IV-22--Requirements for Vehicle To Qualify for Tier 3 Evaporative Emissions Program and Test Fuel Requirements
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                        High altitude &
       Model year          Program/zero evap stds    HS+DI/running loss          Rig            Canister bleed       Leak (except       refueling/spit
                                                                                                                       HHDGV) *             back **
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               MY 2017 TRANSITION PROGRAM
--------------------------------------------------------------------------------------------------------------------------------------------------------
2017....................  Percentage--PZEV zero     CA Ph. 2...........  CA Ph. 2...........  N/A...............  N/A...............  EPA Tier 2 or Tier
                           evap (carryover).                                                                                           3.
2017....................  Percentage--LEV III Opt.  CA Ph. 3...........  CA Ph. 3...........  N/A...............  N/A...............  EPA Tier 3.
                           1.
2017....................  Percentage--LEV III Opt.  CA Ph. 3...........  N/A................  CA Ph. 3..........  N/A...............  EPA Tier 3.
                           2.
2017....................  Percentage--Tier 3......  Tier 3.............  N/A................  EPA Tier 3........  N/A...............  EPA Tier 3.
2017....................  PZEV zero evap only       CA Ph. 2...........  CA Ph. 2...........  N/A...............  N/A...............  EPA Tier 2 or Tier
                           (carryover).                                                                                                3.
2017....................  20/20--PZEV zero evap     CA Ph. 2...........  CA Ph. 2...........  N/A...............  EPA Tier 3........  EPA Tier 2 or Tier
                           (carryover).                                                                                                3.
2017....................  20/20--LEV III Opt. 1...  CA Ph. 3...........  CA Ph. 3...........  N/A...............  EPA Tier 3........  EPA Tier 3.
2017....................  20/20--LEV III Opt. 2...  CA Ph. 3...........  N/A................  CA Ph. 3..........  EPA Tier 3........  EPA Tier 3.
2017....................  20/20--Tier 3...........  Tier 3.............  N/A................  EPA Tier 3........  EPA Tier 3........  EPA Tier 3.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              MY 2018-2021 PHASE-IN PROGRAM
--------------------------------------------------------------------------------------------------------------------------------------------------------
2018-2019...............  PZEV zero evap            CA Ph. 2...........  CA Ph. 2...........  N/A...............  EPA Tier 2 or Tier  EPA Tier 2 or Tier
                           (carryover).                                                                            3.                  3.
2018-2021...............  LEV III Opt. 1..........  CA Ph. 3...........  CA Ph. 3...........  N/A...............  EPA Tier 3........  EPA Tier 3.
2018-2021...............  LEV III Opt. 2..........  CA Ph. 3...........  N/A................  CA Ph. 3..........  EPA Tier 3........  EPA Tier 3.
2018-2021...............  Tier 3..................  Tier 3.............  N/A................  EPA Tier 3........  EPA Tier 3........  EPA Tier 3.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            MY 2022+ FULLY PHASED-IN PROGRAM
--------------------------------------------------------------------------------------------------------------------------------------------------------
2022+...................  LEV III Opt. 2..........  CA Ph. 3...........  N/A................  CA Ph. 3..........  EPA Tier 3........  EPA Tier 3.
2022+...................  Tier 3..................  Tier 3.............  N/A................  EPA Tier 3........  EPA Tier 3........  EPA Tier 3.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* LHDGVs are heavy-duty gasoline vehicles with a GVWR equal to or less than 14,000 lbs; HHDGVs are heavy-duty gasoline vehicles with a GVWR in excess of
  14,000 lbs.
** Incomplete HDGVs without ORVR may defer demonstrating compliance with the spit back requirement on Tier 3 fuel until the 2022 MY.

2. Program Structure and Implementation Flexibilities
a. Percentage Phase-In Requirements
    As proposed, the final Tier 3 evaporative emission standards will 
be phased in over a period of six MYs 2017-2022. Manufacturers 
supported the proposed phase-in schedule and there were no issues 
raised with regard to lead time for any vehicle class. As discussed 
below, there will be three options for the 2017 MY. For the 2018-2019 
MYs, the requirement will apply to 60 percent of a manufacturer's 
nationwide sales of all LDVs, LDTs, MDPVs, and HDGVs (including 
vehicles sold in California and the section 177 states). This will 
increase to 80 percent for MYs 2020 and 2021 and by MY 2022 it will 
apply to 100 percent of sales in

[[Page 23498]]

these four categories. Beginning in MY 2018 any vehicle included in the 
percentage phase-in, except vehicles that had earned allowances, will 
have to meet the leak standard discussed in section IV.D.
    Evaporative emission requirements for the MY 2017 apply only to 
LDVs, LDT1s, and LDT2s as defined in 40 CFR 86.1803-01. To be 
consistent with the start date for Tier 3 exhaust standards, phase-in 
requirements will not include vehicles over 6,000 lbs GVWR until the 
2018 MY. The manufacturers will have three options. The first, which we 
are calling the ``primary'' or ``percentage'' option, requires that a 
value equal to 40 percent of a manufacturer' s LDVs, LDT1s, and LDT2s 
sold outside of California and the states that have adopted the CARB 
ZEV or LEV III programs must meet the Tier 3 evaporative emission 
requirements on average. The 40 percent is calculated based on vehicles 
at or below 6,000 lbs GVWR but compliance can be based on vehicles 
regardless of their GVWR. The second which we are calling the ``PZEV 
zero evap only'' option, requires a manufacturer to sell all of the 
LDVs, LDT1s, and LDT2s certified with CARB as meeting the PZEV 
evaporative emission requirements (zero evap) in MY 2017 throughout all 
of the U.S. and not to offer for sale any non-PZEV zero evap version of 
those specific vehicle models/configurations in any state whose 
vehicles are covered by the Tier 3 evaporative emission standards. 
Thus, this will apply to sales in any state except for California and 
states that have adopted the CARB ZEV or LEV III programs under section 
177 of the Clean Air Act. Under this second option, no tracking of 
sales or end of year compliance calculation will be required. Some 
manufacturers may find this option attractive, as they have more 
limited product offerings and find tracking of production and sales 
more difficult. The third option, which we are terming the 20/20 
option, requires that 20 percent of a manufacturer's LDVs, LDT1s, and 
LDT2s (e.g., equal to or less than 6,000 lbs GVWR) sold outside of 
California and the states that have adopted the CARB ZEV or LEV III 
programs meet the Tier 3 evaporative emission requirements on average 
and that this 20 percent or another 20 percent of vehicles in the three 
groups listed above meet the leak standard discussed in section IV.D. 
Each percentage requirement must be met, (i.e., there is no flexibility 
to permit meeting shortfalls of the hot soak plus diurnal or leak 
standard percentages with higher values from the leak standard 
category). However, as was the case with the 40 percent option above, 
compliance can be based on vehicles regardless of their GVWR. The third 
option was supported by several commenters as a means to address 2017 
MY transition issues related to phase-out of current products and 
phase-in of future products. EPA believes that for these vehicles the 
leak standard will provide emission reduction benefits comparable in 
magnitude to the Tier 3 evaporative emission standards. Thus, under 
this approach, the manufacturers' product transition concerns can be 
addressed while achieving the overall evaporative emission reductions 
from 2017 MY vehicles. It should be noted that these vehicles must also 
meet the 0.020 inch evaporative system leak monitoring requirement 
which also takes effect in the 2017 model year.
    As discussed below, beginning in the 2018 MY, to be counted toward 
the percentages needed to meet the Tier 3 phase-in percentages (e.g., 
60% in 2018 and 2019 MYs) a Tier 3 compliant vehicle must also meet the 
leak standard.
    At the time of certification, manufacturers will identify which 
families will be included in their Tier 3 evaporative emission 
percentage calculations (this could be families above or below the 
individual Tier 3 evaporative emission standards for the given class of 
vehicles (Table IV-19) as well as vehicles meeting CARB's PZEV zero 
evap or LEV III Option 1 standards (Table IV-20) and could also include 
earned allowances as discussed below. The manufacturers will use 
projected sales information for these families plus allowances as 
desired and available, to show how they expect to meet the phase-in 
percentage requirements for the model year of interest. At the end of 
the model year reconciliation the manufacturers will be expected to 
show that the percentages were met. If the percentages are not met, the 
manufacturers will either use additional allowances and/or bring more 
vehicle families/vehicles into the calculation until the sales 
percentage is met. This step is being required because the initial 
demonstration of compliance with the fixed percentage at certification 
is based on projected sales. If the manufacturers did not have to 
demonstrate that the fixed percentages were met, the percentage would 
then be a goal and not a requirement and there would be no means to 
capture the emission reduction shortfalls. This step is unique to the 
evaporative emission program relative to the NMOG+NOX and PM 
programs because the evaporative program involves both fixed 
percentages and ABT. The NMOG+NOX program involves ABT but 
does not involve fixed percentages and the PM program involves fixed 
percentages but does not involve ABT.
    The additional vehicles added to meet the percentage could only be 
meeting the Tier 2 hot soak plus diurnal requirements. In this case, 
use the larger of the 2- or 3-day hot soak plus diurnal certification 
emission levels. Adding these vehicle families/vehicles into the 
calculations (discussed below) may result in a credit deficit for that 
model year for a given averaging set. A manufacturer could not have an 
unresolved deficit for more than three consecutive model years as 
discussed below. The deficit would have to be eliminated with positive 
credits not later than the ABT calculation and credit reconciliation 
which occurs after the fourth model year.
    As discussed above for exhaust emissions, while unlikely, it is 
possible that a manufacturer could in its annual certification preview 
meeting with EPA, indicate that its technology mix is such that it will 
have a credit deficit when the sales percentages requirement is met. 
This could occur if the fleet average evaporative emission value for 
Tier 3 vehicles did not meet the Tier 3 hot soak plus diurnal standard 
for the Tier 3 vehicles in any given averaging set. Also, a 
manufacturer could have a deficit from a previous model. In these 
situations, certifying with a projected or actual deficit would require 
EPA approval after submission of a plan from the manufacturer which 
explains how it will eliminate the deficit within the model years 
permitted. Even if a manufacturer had projected or actual deficits for 
two or three consecutive model years, all accrued deficits would have 
to be eliminated by the reconciliation which occurs after the fourth 
model year. Within this plan, which would have to be submitted and 
approved at each annual certification preview meeting, EPA would expect 
to see progress toward compliance as indicated by such factors as 
improved emissions performance for future test groups, a substantiated 
trend toward a more favorable fleet technology sales mix, no 
backsliding in projected fleet average values, and perhaps other 
situation specific criteria.
    Requiring a showing at the time of certification based on projected 
sales requires due diligence by the manufacturers and EPA, but the Tier 
3 evaporative emissions program allows for fleet averaging, so a 
validation or ``truing up'' of these sales projections after the end of 
the model year is necessary for determining compliance

[[Page 23499]]

with the requirements of the standard. This is discussed in Section 
IV.C.2.d.iii. As discussed further below, validated sales information 
will also be used for earning early allowances and to show compliance 
with the alternative phase-in schedule approach.
    For these purposes, vehicles included in the phase-in percentage 
could be: (1) Families which certified to PZEV zero evap or CARB LEV 
III Option 1 requirements in MYs 2015 and 2016, (2) families certified 
to meet Tier 3 evaporative emission requirements, (3) any vehicle 
family certified to the CARB LEV III Option 2 hot soak plus diurnal 
evaporative emission standards, and (4) vehicles from the early 
allowance program. To qualify as a Tier 3 certification for evaporative 
emission purposes, any new evaporative/refueling emission family 
certifications will have to meet the EPA Tier 3 certification 
requirements for both test procedure and certification test fuel for 
the evaporative (hot soak plus diurnal and canister bleed, running 
loss), refueling, and spit back emission standards. The leak standard 
will apply in the 2018 and later MYs to all Tier 3 vehicles except 
HHDGVs and those from the early allowance program. Furthermore, 
assuming the EPA provisions related to carryover of emissions data are 
met, 2015-2016 MY CARB PZEV zero evap evaporative emissions 
certifications could be carried over until the end of the 2019 MY and 
included as compliant vehicles within the Tier 3 program if they meet 
the other applicable Tier 3 requirements. The same is true for CARB 
LEVIII Option 1 certification, except carryover would be permitted 
through the 2021 MY if they meet the other Tier 3 requirements. See 
Table IV-4 for more detail on the program options and fuel requirements 
by model year.
    The phase-in percentages for MYs 2017 through 2022 reflect a 
percentage phase-in concept applied successfully by EPA in previous 
rules involving evaporative and refueling emissions control. The phase-
in provides an appropriate balance between the needed emission 
reductions and time for the manufacturers to make an orderly transition 
to the new technology on such a broad scale. The higher initial 
percentage here is appropriate because the expected evaporative 
emission control technology is already being used to varying degrees by 
12 manufacturers on over 50 vehicle models today and is projected to 
gain even deeper penetration by 2017 due to the partial zero emission 
vehicles (PZEV) option within the CARB ZEV program.\353\
---------------------------------------------------------------------------

    \353\ See http://driveclean.ca.gov/searchresults_by_smog.php?smog_slider_value=9&x=12&y=12, (last accessed on December 
6, 2013).
---------------------------------------------------------------------------

b. Alternative Phase-In Percentage Scheme
    As part of program flexibility, we are allowing manufacturers to 
demonstrate compliance with the phase-in percentage requirements of the 
evaporative emissions program by using a manufacturer-determined 
alternative phase-in percentage scheme. The alternative phase-in 
percentage provisions allow manufacturers to use a phase-in more 
consistent with product plans such as beginning with a lower 
percentage(s) than required under the primary phase-in during the early 
years or to benefit from producing and selling more than the minimum 
percentage of compliant vehicles early. This flexibility could also be 
helpful in the event that a manufacturer elects to put some vehicles on 
different phase-in schedules for meeting Tier 3 exhaust and evaporative 
emission standards. As explained further below, with some limitations, 
allowances could be used toward compliance with the alternative phase-
in scheme values for any given model year.
    This approach, which was widely supported in comments by the 
manufacturers, would be available beginning in the 2017 MY for all 
manufacturers, except for any manufacturer which used the ``PZEV zero 
evap only'' nationwide option for the 2017 MY for whom the approach 
would be available beginning in 2018 MY. Vehicle and fuel eligibility 
requirements for the program are summarized in Table IV-23. Refer to 
the regulatory text for specific requirements.

                  Table IV-23--Vehicle Qualifications for 2017-2022MY Alternative Phase-in Percentage Schemes & Test Fuel Requirements
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                        High altitude &
       Model year          Program zero evap stds.   HS+DI/running loss          Rig            Canister bleed       Leak (except       refueling/ Spit
                                                                                                                       HHDGV) *             back **
--------------------------------------------------------------------------------------------------------------------------------------------------------
2017....................  PZEV evap (carryover)...  CA Ph. 2...........  CA Ph. 2...........  N/A...............  N/A...............  EPA Tier 2 or Tier
                                                                                                                                       3.
2017....................  LEV III Opt. 1..........  CA Ph. 3...........  CA Ph. 3...........  N/A...............  N/A...............  EPA Tier 3.
2017....................  LEV III Opt. 2..........  CA Ph. 3...........  N/A................  CA Ph. 3..........  N/A...............  EPA Tier 3.
2017....................  Tier 3..................  Tier 3.............  N/A................  EPA Tier 3........  N/A...............  EPA Tier 3.
2018-2019...............  PZEV evap...............  CA Ph. 2...........  CA Ph. 2...........  N/A...............  EPA Tier 2 or Tier  EPA Tier 2 or Tier
                          (carryover).............                                                                 3.                  3.
2018-2021...............  LEV III Opt. 1..........  CA Ph. 3...........  CA Ph. 3...........  N/A...............  EPA Tier 3........  EPA Tier 3.
2018-2022...............  LEV III Opt. 2..........  CA Ph. 3...........  N/A................  CA Ph. 3..........  EPA Tier 3........  EPA Tier 3.
2018-2022...............  Tier 3..................  Tier 3.............  N/A................  EPA Tier 3........  EPA Tier 3........  EPA Tier 3.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* LHDGVs are heavy-duty gasoline vehicles with a GVWR equal to or less than 14,000 lbs; HHDGVs are heavy-duty gasoline vehicles with a GVWR in excess of
  14,000 lbs.
** Incomplete HDGVs without ORVR may defer demonstrating compliance with the spit back requirement on Tier 3 fuel until the 2022 MY.

    Under this approach, before the 2017 MY (2018 MY for a manufacturer 
which used the ``PZEV zero evap only'' nationwide option for the 2017 
MY), a manufacturer will present a plan to EPA which demonstrates that 
the sum of the products of a weighting factor and the percentages of 
their U.S. vehicle sales for each model year from 2017 (2018) through 
2022 is greater than or equal to 1280 if the program started in the 
2017 MY (or 1040 if the program started in the 2018 MY). The 1280 and 
1040 numerical values are equal to the sum of the product of the 
weighting factors and the percentage requirements for MY 2017 or 2018 
start dates, respectively, as applicable through MY 2022. These are 
calculated in the following manner: 
[(6)(2017MY%)+(5)(2018MY%)+4(2019MY%)+3(2020MY%)

[[Page 23500]]

+2(2021MY%)+(1)(2022MY%)]. The 2017 MY portion of the calculation would 
not be included if the manufacturer used the ``PZEV zero evap only'' 
nationwide option and thus started the alternative phase-in scheme in 
the 2018 MY. Under the regulations, EPA has the authority to question 
elements of the plan and to seek clarifications and potential changes 
as needed. EPA could disapprove the plan and potentially not allow the 
use of an alternative phase-in scheme for the model year of interest if 
the manufacturer does not present a viable explanation and rationale as 
to how the required numerical sum for the phase-in would be achieved.
    EPA also sought comment on including the 20 percent value hot soak 
plus diurnal value from the 20/20 option described above for 2017 MY in 
this calculation. Manufacturers generally supported including the 2017 
MY in the calculation but did not clearly state whether the 40 percent 
or 20/20 option approach or both were supported. EPA has decided to 
include both options for the 2017 MY in the alternative phase-in 
percentage scheme; 40 percent as described above or 20 percent, with 
the stipulation that any vehicle used to meet the 20 percent 
requirement in the 2017 MY would also have to meet the OBD evaporative 
leak monitoring requirements and the leak standard. In other words, the 
flexibility of using different vehicles as allowed for the 20/20 option 
in the primary phase-in scheme is not included in the alternative 
phase-in. Including this restriction avoids the complexity that would 
be added if two different sets of vehicles were allowed to meet the two 
elements of the 20/20 option for the 2017 MY, as in the primary phase-
in (e.g., expanding the calculation and tracking requirements and 
incorporating leak standard compliance and OBD evaporative system 
monitoring as part of the alternative phase-in scheme). If a 
manufacturer's hot soak plus diurnal value exceeded 20 percent then 
that larger value could be used in the alternative phase-in 
calculation. However, the leak standard value cannot be less than 20 
percent and for the first 20 percent the hot soak plus diurnal and the 
leak must be on the same vehicle and that vehicle must meet the 0.020 
inch OBD evaporative system leak monitoring requirement. Compliance 
would be calculated in the following manner: 
[lsqb](6)(2017MY%)+(5)(2018MY%)+(2019MY%)+3(2020MY%)+2(2021MY%)+(1)(2022
MY%)[rsqb]. If choosing the 20/20 option approach for MY 2017, the 
value to be met or exceeded in the alternative phase-in would be 1160 
which is based on substituting the required phase-in percentages for 
MYs 2017-2022 in the equation. Under this option as above, before the 
2017 MY, the manufacturer would have to submit a plan to EPA which 
demonstrates that the sum of the products of a weighting factor and the 
percentages of their U.S. vehicle sales for each model year from 2017 
through 2022 is greater than or equal to 1160. A manufacturer that over 
complies with the targets (i.e., 1040, 1160, 1280) may not trade the 
excess to another manufacturer. Also, a manufacturer must include all 
of its affected products in program, not just specific vehicle 
categories or subcategories.
    A manufacturer's alternative phase-in plan must be approved by EPA 
prior to the start of production for a given model year and will have 
to be reviewed with EPA each subsequent model year to confirm that the 
manufacturer's target percentages are being met. This would be expected 
to occur at the annual certification preview meeting. Manufacturers not 
meeting their target goals must present revised plans for EPA approval 
to show how the target percentages and equivalent emission standards 
will be met. Manufacturers using the alternative phase-in percentage 
scheme must still show compliance with the hot soak plus diurnal 
standards in each year as discussed in Section IV.C.2.d.iii even if 
they fall short of their individual target goal percentages for a given 
year. EPA is not requiring that manufacturers include Tier 2 vehicles 
in the calculation for a given model year if they fall short of 
projections (e.g., if a manufacturer projects 25% in a given model year 
but only achieves 22%) because it will have to be made up in a 
subsequent year using a lower multiplier.
c. Allowance Program
    We are finalizing incentives for early introduction of vehicles 
compliant with the Tier 3 evaporative emission regulations. 
Manufacturers can take advantage of these incentives prior to MY 2018 
by selling vehicles that meet the Tier 3 evaporative emission 
regulations earlier than required or in greater numbers than required. 
Vehicle eligibility requirements for the allowance program are 
summarized in Table IV-24. Refer to the regulatory text for specific 
provisions.

                                      Table IV-24--Vehicle Eligibility To Earn Allowances & Test Fuel Requirements
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                      High altitude &
        Model year & program            Vehicle category       HS+DI/running loss             Rig               Canister bleed     refueling/ spitback *
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  EVAPORATIVE EMISSIONS
--------------------------------------------------------------------------------------------------------------------------------------------------------
2015-2016 PZEV zero evap carryover.  LDV, LDT..............  CA Ph. 2..............  CA Ph. 2.............  N/A..................  EPA Tier 2/Tier 3.
2015-2016 LEV III Option 1.........  LDV, LDT..............  CA Ph. 3..............  CA Ph. 3.............  N/A..................  EPA Tier 2/Tier 3.
2015-2016 LEV III Option 2.........  All...................  CA Ph. 3..............  N/A..................  CA Ph. 3.............  EPA Tier 2/Tier 3.
2015-2016 Tier 3...................  All...................  Tier 3................  N/A..................  Tier 3...............  EPA Tier 3.
2017 ``PZEV evap only'' carryover..  LDT 3&4...............  CA Ph. 2..............  CA Ph. 2.............  N/A..................  EPA Tier 2/Tier 3.
2017 ``Percentage'' option--LEV III  LDT3 &4 MDPV, HDGV....  CA Ph. 3..............  CA Ph. 3.............  N/A..................  EPA Tier 3.
 Option 1.
2017 ``Percentage'' option LEV III-- LDT3/4 MDPV, HDGV.....  CA Ph. 3..............  CA Ph. 3.............  CA Ph. 3.............  EPA Tier 3.
 Option 2.
2017 ``Percentage'' option Tier 3..  LDT3/4 MDPV, HDGV.....  Tier 3................  EPA Tier 3...........  EPA Tier 3...........  EPA Tier 3.
2017 ``20/20'' and all MY alt phase- Not available.........
 in schemes.
2018+ LDV, LDT, MDPV & HDGV........  Not available.........
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 23501]]

 
                                                                         ORVR **
--------------------------------------------------------------------------------------------------------------------------------------------------------
2015-2017 Early ORVR...............  Complete HDGV >10,000   ......................  .....................  .....................  EPA Tier 2/Tier 3.
                                      but <=14,000 lbs.
                                      GVWR.
2015-2021 Early ORVR...............  Complete HDGV >14,000   ......................  .....................  .....................  EPA Tier 2/Tier 3.
                                      lbs. GVWR.
2015-2021 ORVR.....................  Incomplete HDGV >8,500  ......................  .....................  .....................  EPA Tier 2/Tier 3.
                                      lbs. GVWR.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* LHDGVs are heavy-duty gasoline vehicles with a GVWR equal to or less than 14,000 lbs; HHDGVs are heavy-duty gasoline vehicles with a GVWR in excess of
  14,000 lbs. Incomplete HDGVs without ORVR may defer demonstrating compliance with the spit back requirement on Tier 3 fuel until the 2022 MY.
** All ORVR certifications must use Tier 3 fuel by the 2022 model year.

    As described below, manufacturers can earn ``allowances'' for 
selling any vehicle meeting the Tier 3 evaporative emission program 
requirements as specified in Table IV-22 earlier than required. The 
vehicles may be LDVs, LDTs, MDPVs, or HDGVs. Specifically, the 
allowance program includes the following: (1) For MYs 2015 and 2016, 
any LDVs and any LDTs meeting the Tier 3 evaporative emission program 
requirements as specified in Table IV-22 which are sold outside of 
California and the states that have adopted CARB's ZEV or LEV III 
programs, (2) for MYs 2015-2017, any MDPV or HDGV meeting the Tier 3 
evaporative emission program requirements as specified in Table IV-22 
early and sold in any state, (3) for MY 2017, any LDT3/4 meeting the 
Tier 3 evaporative emission program requirements as specified in Table 
IV-22 and sold outside of California and the states that have adopted 
CARB's LEV III or ZEV programs, and (4) for MYs 2015-2017, any complete 
or incomplete HDGV with a GVWR greater than 10,000 lbs meeting the EPA 
refueling emissions regulations and sold outside of California and the 
states that have adopted CARB's LEV III program. EPA asked for comment 
on extending the ORVR requirement to all HDGVs, complete and 
incomplete. As discussed in section IV.C.4.b, we are extending ORVR to 
all complete vehicles over 14,000 lbs GVWR, but are not including 
incomplete vehicles over 8,500 lbs GVWR in the ORVR requirement at this 
time. However, we are permitting complete vehicles over 14,000 lbs GVWR 
and incomplete HDGVs meeting the refueling emission standard to earn 
allowances through the 2021 MY. Any complete or incomplete HDGV 
eligible to earn allowances for the model years and areas discussed 
above will earn them at a 1:1 rate for refueling emissions compliance 
purposes and at a 2:1 rate for Tier 3 evaporative emissions purposes 
because the refueling emission reductions are much larger.
    Furthermore, for the 2017 MY, manufacturers choosing EPA's 
``percentage'' option (see Section IV.C.2.a) could earn allowances for 
sales of LDT3s, LDT4s, MDPVs, and HDGVs that meet the CARB LEV III or 
Tier 3 evaporative emission standards and related requirements assuming 
their LDV, LDT1/2 sales meet the 40 percent requirement. Similarly, 
manufacturers choosing EPA's ``PZEV zero evap only'' option could earn 
allowances in MY 2017 for LDT3/4s, MDPVs, and HDGVs that meet the 
``PZEV zero evap'' evaporative emission standards, CARB LEV III, or EPA 
Tier 3 evaporative emission standards and related requirements. EPA has 
decided not to include allowances for the 2017MY for any manufacturer 
using the 20/20 option since it would involve identifying not only the 
vehicles exceeding the 20 percent for the Tier 3 evaporative emission 
requirements but also the vehicles exceeding the 20 percent for the 
leak standard and these may be different vehicles. For both the 
``percentage'' and ``PZEV zero evap only'' options for the 2017 model 
year, to avoid double counting, the allowances will be earned only for 
those vehicles sold outside of California and the states that have 
adopted CARB's LEV III/ZEV program requirements.
    To qualify as a Tier 3 vehicle for evaporative emission allowance 
purposes the vehicle must meet the requirements summarized in Table IV-
22. Manufacturers will earn one allowance for each qualifying vehicle 
sold. Manufacturers can use these allowances in MY 2017 through 2022 to 
help demonstrate compliance with the phase-in percentage requirements 
and fleet average evaporative emission standards for those years. Since 
credits and allowances serve primarily the same purpose and allowing 
for splits of allowances/credits greatly complicates program 
implementation, the final rule provides that manufacturers can only 
earn allowances in MYs 2015-2016 for any LDVs and LDT1/2s meeting the 
Tier 3 evaporative emission regulations which are sold outside of 
California and the states that have adopted CARB's ZEV or LEV III 
programs and for MYs 2015-2017 for any qualifying LDT3/4, MDPV, and 
HDGV.\354\
---------------------------------------------------------------------------

    \354\ LDVs and LDT1/2 sold in California and states which have 
adopted the LEV III or ZEV programs cannot generate allowances 
because these programs will already require zero evap technology 
vehicles in those states in MYs 2015-2016.
---------------------------------------------------------------------------

    Allowances will be used in the compliance determination in the 
following manner. Vehicles qualifying for allowances can be used in the 
fleet average evaporative emission standard calculation for any year 
during the phase-in. This applies to the primary phase-in and 
alternative phase-in programs. Allowance vehicles will be entered into 
the compliance calculation with an emission value equivalent to the 
evaporative emission standard for their vehicle category from Table IV-
19 even if it was certified to CARB PZEV zero evap or LEV III Option 1 
standards (Table IV-20). For the percent phase-in requirement in either 
the primary or alternative phase-in schemes, allowance vehicles will 
count for one vehicle for each allowance used within their vehicle 
category. For the primary scheme this will be counted as one

[[Page 23502]]

vehicle, but for the alternative phase-in option the value will be 
multiplied by the weighting factor (6 for 2017, 5 for 2018, 4 for 2019, 
3 for 2020, etc). Within the alternative phase-in scheme the 
manufacturer will be limited to using these early allowances for no 
more than 10 percentage points of the phase-in requirements in any 
given model year (e.g., MYs 2017-2022). EPA believes this limitation is 
appropriate since early use in the alternative phase-in scheme is 
multiplied and early introduction of ``zero evap'' technology should be 
encouraged, but not necessarily at the expense of its widespread use 
across the various vehicle categories as the phase-in progresses. The 
allowances are designed primarily to facilitate manufacturer transition 
during the program phase-in. As such, they may not be traded between 
manufacturers and unused allowances will expire after the 2022 MY.
    An example here may be helpful in demonstrating how allowances will 
work. Take a hypothetical manufacturer who earned a total of 10,000 
allowances in MYs 2015 and 2016 and sells 100,000 units per year. In MY 
2018, the manufacturer will have a phase-in requirement of 60 percent 
or 60,000 vehicles. For the primary phase-in option the manufacturer 
could use part or all of its allowances in 2018 without restriction. 
For the alternative phase-in scheme assume the manufacturer set its 
alternative phase-in value at 60 percent for the 2018 MY. The final 
regulations limit the use of allowances to 10 percentage points of the 
60 percent or in this case 10,000 vehicles out of 60,000. Without a 
multiplier this will require the use of all 10,000 allowances in 2018, 
but with the multiplier of 5 for MY 2018 only 2,000 allowances are 
needed to reach the 10 percentage point maximum. Using a similar 
calculus, the manufacturer could use another 10 percentage points in MY 
2019, but it will require 2,500 allowances to reach this level since 
the multiplier is 4 assuming sales remain at 100,000 units per year. 
The number of allowances to reach the 10 percentage point level will 
increase each year as the multiplier decreases.
d. Evaporative Emissions Averaging, Banking, and Trading
i. Introduction
    Throughout EPA's programs for mobile source emission controls, we 
have often included emission averaging programs for exhaust emissions. 
An emission averaging program is an important factor we take into 
consideration in setting emission standards under the Clean Air Act. An 
emission averaging program can reduce the cost and improve the 
technological feasibility of achieving standards, helping to ensure the 
standards achieve the greatest achievable reductions, considering cost 
and other relevant factors, in a time frame that is earlier than might 
otherwise be possible. Manufacturers gain flexibility in product 
planning and the opportunity for a more cost-effective introduction of 
product lines meeting a new standard. Emission averaging programs also 
create an incentive for the early introduction of new technology, which 
allows certain emission families to act as leaders for new technology. 
This can help provide valuable information to manufacturers on the 
technology before they apply the technology throughout their product 
line.
    These programs generally involve averaging and banking, and 
sometimes trading (ABT). Averaging allows a manufacturer to certify one 
or more families at emission levels above the applicable emission 
standards as long as the increased emissions are offset by one or more 
families certified below the applicable standards. These are referred 
to as individual family emission limits (FELs). The over-complying 
families generate credits that are used by the under-complying 
families. Compliance is determined on a total mass emissions basis to 
account for differences in production volume, and on other factors as 
necessary such as useful life. The average of all emissions for a 
particular manufacturer's production within a vehicle category must be 
at or below the level of the applicable emission standards. Banking 
allows a manufacturer to generate emission credits and bank them for 
future use in its own averaging program in later years. Trading allows 
a manufacturer to sell credits or obtain credits from another 
manufacturer.
    EPA proposed and is finalizing an emissions ABT program for the 
Tier 3 hot soak plus diurnal evaporative emissions standards. The 
evaporative emissions ABT program is generally structured and operates 
the same as that for exhaust emissions as discussed in Section 
IV.A.7.m. The major difference is the added requirement to reconcile 
compliance with the fixed percentage requirement as discussed in detail 
in Section IV.C.2.a. Also, there is a five year credit life for 
evaporative emissions as opposed to the longer interim values for 
NMOG+NOX FTP and SFTP credits.
    This is the EPA's first averaging type program for evaporative 
emissions from light-duty or heavy-duty vehicles. It does not apply to 
the canister bleed standard or the leak standard because it is the low 
altitude ``zero evap'' hot soak plus diurnal standard which will drive 
the fundamental approach used to comply with all of these requirements. 
We sought comment on the value of including trading in the program. The 
comments from the Alliance of Automobile Manufacturers and the 
Association of Global Automakers very generally supported the inclusion 
of trading but provided no detail. Upon follow-up from EPA no 
manufacturer provided any further explanation on the need for the 
program or how they might use it.\355\ In past similar programs for 
exhaust emissions there have been only a few trades, but incorporating 
trading within the program adds a degree of flexibility if a 
manufacturer finds itself in a credit deficit situation. Thus, we have 
decided to include trading, but credit trades are limited based on the 
same averaging set restrictions as discussed below for averaging and 
banking.
---------------------------------------------------------------------------

    \355\ See Alliance of Automobile Manufacturers and Association 
of Global Automakers comments on the NPRM (dated July 1, 2013) and 
Passavant, G. (June 2013) EPA and Auto Industry Meeting Related to 
Tier 3 Evap and OBD NPRM. Memorandum to the docket.
---------------------------------------------------------------------------

    The evaporative emissions ABT program will start with the 2017 MY 
for the percentage and 20/20 options. Prior to the 2017 MY and for 
other options as discussed in Section IV.C.2.b, manufacturers may earn 
allowances. The programs will continue for the 2018 MY and beyond for 
all manufacturers regardless of their 2017 MY option and will not 
sunset, as does the allowance program. Vehicles generating ABT credits 
in the 2017 MY or later will not be permitted to also generate 
allowances as this would be double counting.
    A key element of an averaging program is the identification of the 
averaging sets. This establishes the basis within which evaporative 
emission families can be averaged for purposes of compliance as well as 
credit and deficit determinations. As proposed, we are finalizing four 
averaging sets and the applicable emission standard for each of the 
averaging sets as shown in Table IV-19. Except as noted in Section 
IV.C.2.d.2 below, credit exchanges between averaging sets will not be 
permitted. Participation in ABT is voluntary since a manufacturer could 
elect to certify each family within the averaging set to its individual 
standard as if there were no averaging program.
    An evaporative emission ABT calculation and assessment involves two 
distinct steps. The first is the determination of the credit/deficit 
status of each family relative to its applicable

[[Page 23503]]

standard from Table IV-19. The second is the role of ABT calculations 
in the overall compliance demonstration which is discussed in Section 
IV.C.2.d.
ii. Family Emission Limits
    A manufacturer choosing to participate in the evaporative emissions 
ABT program will certify each emission family to an FEL that applies 
for the hot soak plus diurnal standard for low altitude testing. The 
FEL selected by the manufacturer becomes the emission standard for that 
emission family. Emission credits (or deficits) are based on the 
difference between the emission standard that applies (by vehicle 
category) and the FEL. The vehicles will have to meet the FEL for all 
emission testing. As mentioned in Section IV.C.1.b., above, for 
vehicles certified with FELs above or below the applicable standard for 
testing at low altitude, the same differential will apply to the FELs 
for high-altitude. This high-altitude FEL will not be used for any 
emission-credit calculations, but it will be used as the emission 
standard for compliance purposes.
    The final rule provides that the FELs selected by the manufacturer 
must be selected at 0.025 g/test increments above or below the 
applicable Tier 3 evaporative emission standards for each vehicle 
category. For example, for LDVs the increments for the FELs would be +/
- 0.025 from 0.300 g/test (e.g., 0.225, 0.250, 0.275, 0.300, 0.325, 
0.350, 0.375 . . . 0.500). The FEL is used in the compliance 
demonstration not the certified level. The certified level must be 
below the FEL, but the FEL could be a higher value than the closest 
increment value. For example, a certified value of 0.235 g/test could 
support an FEL of 0.250 g/test or any other higher increment value. One 
commenter asked that the gradation be finer than 0.025 g/test, but EPA 
believes this is the appropriate increment, since the standard itself 
is the sum of two values and rounding of the measured values is 
involved.
    FELs are capped such that they cannot be set any higher than 0.500 
g/test for LDVs, 0.650 g/test for LDT1s and LDT2s, 0.900 g/test for 
LDT3s and LDT4s, 1.000 g/test for MDPVs, 1.4 g/test for HDGVs at or 
below 14,000 lbs GVWR, and 1.9 g/test for those above 14,000 lbs GVWR, 
respectively. These FEL caps are the 3-day hot soak plus diurnal 
emission standards applicable under EPA's existing regulations. While 
we asked for input on these FEL caps and vehicle groupings, no party 
provided comment.
    Total evaporative emission credits (or deficits) under the Tier 3 
hot soak plus diurnal ABT program will be calculated differently in the 
2017 model year and the 2018 and later model years. For 2017 
calculations will be based on sales in the U.S. excluding California 
and the section 177 states which have adopted the LEV III/ZEV programs. 
For 2018 and later model years it will be based on all 50 states. 
Calculations will use the following equation: Credits = (fleet average 
standard-fleet average FEL) x ``U.S. sales''. The ``fleet average 
standard'' term here is the applicable Tier 3 hot soak plus diurnal 
standard for the vehicle category from Table IV-19. The sales number 
used in the 2018 and later MY calculation will be the number of 
vehicles of the evaporative emission families in that category sold in 
the U.S. which are subject to the Tier 3 evaporative emission 
standards. Emission credits banked under the evaporative emission ABT 
program will have a five year credit life and will not be discounted. 
This means the credits will maintain their full value through the fifth 
model year after the model year in which they are generated. At the 
beginning of the sixth model year after they are generated, the credits 
will expire and cannot be used by the manufacturer. We are limiting 
credit life so there is a reasonable overlap between credit generating 
and credit using vehicles. As mentioned above, for purposes of the 
compliance calculation, allowance vehicles will have an FEL equivalent 
to the EPA emission standard (Table IV-19) for their respective vehicle 
category.
iii. Compliance Demonstration
    Demonstration of compliance with the evaporative emissions 
standards is done after the end of each model year. There are two 
steps. In the first step, as discussed above, manufacturers must show 
compliance with the applicable phase-in percentages from the primary 
phase-in scheme (i.e., 40, 60, 80, and 100), the 20/20 option for MY 
2017, or an alternative phase-in percentage scheme. It is sales from 
these families together with their respective FELs which will be used 
to make the demonstration of compliance with the emission standard on 
average within each vehicle averaging set. Compliant vehicle types for 
these purposes are the same as described in Section IV.C.1.c above for 
projected sales. If the required sales percentages are not met by 
direct sales or allowances, non-Tier 3 vehicles would have to be 
identified to make up the shortfall in this calculation but would not 
be subject to the canister bleed or leak standard requirements.
    In the second step, using the FELs, manufacturers calculate the 
sales-weighted average emission levels within each of the four vehicle 
categories using sales for each family.\356\ Manufacturers are allowed 
to use credits only within a defined averaging set. The averaging sets 
are: (1) LDVs and LDT1s, (2) LDT2s, (3) LDT3s, LDT4s, and MDPVs, and 
(4) HDGVs. These sales-weighted calculated values must be at or below 
the emission standard for that vehicle category as shown in Table IV-
19, (unless credits from ABT are used). If the difference between the 
standard and the sales-weighted average FEL is a positive value this 
could generate banked credit available for future use. If the 
difference between the standard and the sales-weighted average FEL is a 
negative value this would be a credit deficit which could be covered by 
previously banked credits. Credit deficits will be allowed to be 
carried forward through negative banking. However, manufacturers are 
required to make up any deficits within the three subsequent model 
years with credits from vehicles in the same averaging set, except as 
described below. That is, after calculations for the fourth model year 
are complete, all previous deficits from the preceding model years will 
have to be resolved by credits generated by the manufacturer or 
acquired through trading from vehicles within the same averaging set. 
As an illustration, a credit deficit accumulated in MY 2017 would have 
to be eliminated not later than the time that the 2020 MY ABT 
calculation is submitted to EPA. In no case will a manufacturer be 
permitted to carry a deficit (negative credit balance) for more than 
three consecutive model years. Using a similar illustration, all credit 
deficits accumulated in MYs 2017, 2018, and 2019 would have to be 
eliminated not later than the time that the 2020 MY ABT calculation is 
submitted to EPA.
---------------------------------------------------------------------------

    \356\ For MY 2017 calculations will be based on sales in the 
U.S. excluding California and the section 177 states which have 
adopted the LEV III/ZEV programs. For 2018 and later model years it 
will be based on all 50 states.
---------------------------------------------------------------------------

    As discussed above, manufacturers are required to identify and 
include in the calculations for each of the four averaging sets, 
vehicle families from each of the vehicle categories (see Table IV-19) 
until the total annual nationwide sales in the given model year equals 
or exceeds the prescribed percentages. This could include non-Tier 3 
vehicles. If the inclusion of non-Tier 3 vehicles results in an 
exceedance of the hot soak plus diurnal emission standard for that 
category of vehicles, the credit deficit would have to be made up in a 
subsequent model year. Credits from

[[Page 23504]]

banking and trading can be used to cover deficits at any time within 
the appropriate averaging set.
    Allowances can also be used to demonstrate compliance with the 
percentage phase-in requirements and the vehicle category average 
emission standard. For purposes of the percentage phase-in 
requirements, vehicles which have earned allowances are counted as 
compliant in the percentage calculation. For purposes of the 
calculations for compliance with the emission standard, allowance 
vehicles enter into the evaporative emissions compliance calculation as 
having an emission rate equivalent to the standard for that category of 
vehicle. Thus, allowance vehicles can help in demonstrating compliance 
with the percentage phase-in requirement (up to ten percentage points 
per model year in the alternative phase-in scheme) and can help in 
reducing deficits since their calculation value is equivalent to the 
level of the standard.
    As presented in detail above, during the 2017-2021 MYs EPA is 
allowing manufacturers limited flexibility to meet the percentage 
phase-in requirements using carryover certification data from vehicles 
certified to CARB PZEV zero evap and CARB LEV III Option 1 standards in 
the 2015 or 2016 model years. These vehicles may have certification 
values slightly higher than those of EPA's Tier 3 program for the given 
vehicle and vehicle category. Since the emission standard values in 
Table IV-19 and Table IV-20 are very similar for any given vehicle 
category, for purposes of simplification during the phase in, EPA in 
the final rule provides that any CARB PZEV zero evap or CARB LEV III 
Option 1 vehicles used in the 2017-2021MYs emission standard compliance 
determination be entered into the calculation with the emission level 
equivalent to the Tier 3 vehicle category in which the vehicle model 
would otherwise fit. However, we are not allowing manufacturers to 
generate emission credits for families certified with EPA based on 
carryover CARB PZEV zero evap or CARB LEV III Option 1 evaporative 
emissions data as provided for in Table IV-20. We are not including 
these vehicles in the ABT program since the programs are not directly 
comparable, and the structure of the current CARB ZEV program, which is 
the genesis of most PZEV zero evap offerings, allows for a different 
number of PZEV sales as a function of manufacturer size and CARB LEV 
III Option 1 does not permit averaging.
    As mentioned above, we are limiting use of credits to only within a 
defined averaging set. Cost effective technology is available to meet 
the hot soak plus diurnal emission standards on average within each of 
the vehicle categories in the averaging sets, especially since the 
standards are designed to accommodate nonfuel hydrocarbon background 
emissions. Thus, further flexibility is not needed. Moreover, we are 
constraining averaging to within these sets because of equity issues 
for the manufacturers. We are concerned that in the absence of such 
constraints the four or five manufacturers with a wide variety of 
product offerings in most or all of these categories would have a 
competitive advantage over the majority of manufacturers which have 
more limited product lines. This effect could be even more pronounced 
if the number of evaporative families is considered, since larger more 
diverse manufacturers have more models and thus more evaporative 
families.
    Nonetheless, manufacturer use of credits from different averaging 
sets to demonstrate compliance is permitted in limited cases. As noted 
above, if a manufacturer has a credit deficit at the end of a model 
year in a given averaging set, they will have to use credits from the 
same averaging set during the next three model years to make up the 
deficit. However, if a deficit still exists at the end of the third 
year (i.e., the deficit has existed for three consecutive model years), 
we are incorporating provisions to permit a manufacturer to use banked 
or traded credits from a different averaging set to cover the remaining 
deficit in the fourth model year's ABT calculation, with the following 
limitations. Manufacturers are able to use credits from the LDV and 
LDT1 averaging set to address remaining deficits in the LDT2 averaging 
set, and vice versa. Furthermore, manufacturers are permitted to use 
credits from the LDT3, LDT4, and MDPV averaging set to address 
remaining deficits in the HDGV averaging set, and vice versa. No other 
use of credit exchanges across different averaging sets is allowed. 
These restrictions are being finalized because of equity concerns 
caused by the different nature and size of various manufacturer product 
lines.
    For both the percentage phase-in and sales-weighted average 
calculation steps above, we are basing the calculation on nationwide 
sales (excluding California and the section 177 states which have 
adopted the LEVIII/ZEV programs) in the 2017 MY since the anti-
backsliding provisions of the LEV III evaporative emissions program are 
in place through the 2017 MY. The program uses annual nationwide sales 
beginning in the 2018 MY. We believe this approach is consistent with 
the manufacturers' plans for 50-state vehicles. A program design which 
enables a nationwide program has been an important premise of this 
rulemaking. Furthermore, this is simpler for the manufacturers and for 
EPA since it relieves the need to project future model year sales or 
track past model year sales at a disaggregated level. We recognize that 
decisions by the manufacturers on a national fleet versus a bifurcated 
approach such as exists today (California and the section 177 states 
which have adopted the LEVIII/ZEV programs separate from the rest of 
U.S. sales) may not yet have been made. The CARB LEV III and EPA phase-
in requirements are identical beginning in 2018, so EPA sees little 
need for concern that a nationwide-based accounting approach could lead 
to disproportionate state by state impacts or the encouragement of 
practices which would lead to any particular state or area not 
receiving the anticipated emission reductions with this nationwide 
approach to the calculation.
    As discussed above, manufacturers not meeting the percentage phase-
in requirements will need to include non-Tier 3 vehicles in the count 
and include their emissions in the overall calculation of compliance 
with the hot soak plus diurnal standard and resolve shortfalls in 
compliance with the emission standard with future reductions, earned 
allowances, or credits. These non-Tier 3 vehicles would not be subject 
to leak standard or canister bleed standard requirements. The 
additional vehicles could only be meeting the Tier 2 hot soak plus 
diurnal requirements and adding these vehicle families/vehicles into 
the calculation may result in a credit deficit. A manufacturer could 
not have an unresolved deficit for more than three model years as 
discussed below. The deficit would have to be eliminated with positive 
credits not later than the ABT calculation and credit reconciliation 
which occurs after the fourth model year.
    Resolving this sales percentage shortfall problem becomes a bit 
more complicated for the 2017 MY 20/20 option because it requires that 
20 percent of vehicles meet the Tier 3 evaporative emission 
requirements and that 20 percent meet the leak standard. These may or 
may not be the same vehicles. As a means to resolve this potential 
problem, EPA is requiring that any shortfall of either of the 20 
percent values (Tier 3 evaporative or leak standard) for the 2017 MY be 
covered by allowances or by future sales of vehicles meeting the Tier 3 
evaporative emission requirements in excess of the

[[Page 23505]]

evaporative emission percentage sales requirement for that MY or some 
combination of MYs. For example, if a manufacturer was five percentage 
points short of either the 20 percentage points for the hot soak plus 
diurnal or the 20 percentage points for the leak standard in the 2017 
MY, then it will have to accelerate sales of vehicles meeting Tier 3 
evaporative emission requirements in the 2018-2021 MYs to cover the 5 
percentage points (e.g., 65 percent in 2018 instead of 60 percent or 63 
percent in 2018 MY and 62 percent in the 2019 MY, etc.). These vehicles 
as Tier 3 vehicles in MY 2018 or later would also have to meet the leak 
standard.
e. Small Volume Manufacturers
    As flexibility, we are establishing provisions for small volume 
manufacturers and for those small business manufacturers and 
operationally independent small volume manufacturers with average 
annual nationwide sales of 5,000 units or less.\357\ These 
manufacturers would be permitted to delay meeting the Tier 3 
evaporative emission standards, including the requirement to use EPA 
certification test fuel, until the 2022 MY. See pages 29892 and 29998-
29999 of the preamble to the NPRM and Section IV.G.5 below for a 
discussion of the 5,000 vehicle threshold. This includes the hot soak 
plus diurnal standards, the canister bleed emission standard, and the 
leak standard. In the interim, these vehicles must meet the existing 
evaporative and refueling emission standards. The initial determination 
of whether a manufacturer is under the 5,000 unit threshold will be 
based on the three year average of actual nationwide sales for MYs 
2012-2014. This allowance would not be affected if a qualifying 
manufacturer's nationwide sales later exceed that value before 2022. 
Similarly, new market entrants (not in the market in the 2012 MY) with 
projected sales of less than 5,000 units could be covered by the small 
volume manufacturer provisions. However, in this case if actual running 
average nationwide sales exceed 5,000 units per year in any three 
consecutive model years they will have to meet the Tier 3 evaporative 
requirements in the third model year thereafter. For example, if a new 
market entrant in 2015 projects nationwide production of 4,000 units 
per year and the average of actual values in 2015-2017 exceeds 5,000 
units per year they will have to meet Tier 3 evaporative requirements 
by the 2020 MY.
---------------------------------------------------------------------------

    \357\ See 40 CFR 86.1838-01(d).
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3. Technological Feasibility
    Evaporative/refueling emission control systems are an integral part 
of the overall vehicle engine and fuel system. EPA is establishing two 
revised and three new standards in this rule (2-/3-day hot soak plus 
diurnal standards, high altitude standards canister bleed standards, 
fuel rig SHED standard, leak standard) and a new test fuel which 
applies to these standards as well as the current running loss, 
refueling, and spit back emission standards.
    Hot soak plus diurnal emissions are fuel vapors which arise from 
the fuel system when it is parked immediately after operation (hot 
soak) and during daily ambient heating and cooling or by means of 
permeation when the vehicle is at rest. Control of hot soak plus 
diurnal emissions is primarily achieved by routing fuel vapors to a 
canister filled with activated carbon. These vapors are stored on the 
carbon and purged in the engine during vehicle operation. Hot soak plus 
diurnal emission rates vary with fuel vapor pressure, temperature, and 
fuel system design. Permeation emissions have been reduced by improving 
fuel tank and fuel line materials. Permeation emissions are sensitive 
to the gasoline ethanol content. While EPA has required ethanol in the 
fuel used for assessing evaporative system durability since 2004, Tier 
3 is the first rule to require the certification test fuel for 
gasoline-fueled vehicles to include ethanol (E10).
    Canister bleed emissions are fuel vapors which diffuse from the 
canister vent as a result of the normal redistribution of vapors within 
the activated carbon while the vehicle is at rest. The emission rate 
depends on the tank volume, its fill quantity, the size and 
architecture of the canister and the characteristics of the carbon 
itself. While the biggest effect of this vapor redistribution is a 
uniform vapor concentration within the canister, it can also cause 
vapors to escape through the canister vent even without continued 
canister loading resulting from fuel tank heating.
    Vapor leaks in the vehicle fuel/evaporative system can arise from 
micro-cracks or other flaws in various fuel/evaporative system 
component structures or welds, problems with component installations, 
and more generally from connections between components and fuel lines 
and vapor lines. Control of leaks is especially important to achieving 
full useful life emission control system performance.
    In Tier 3, the emissions test fuel is changing from 9 RVP E0 to 9 
RVP E10. EPA does not expect the change in emissions test fuel to 
affect refueling, spit back, or running loss compliance technology or 
strategies.
    While these elements of the evaporative/refueling program are 
separate requirements for compliance purposes, the integrated nature of 
the design and operation of the evaporative/refueling control systems 
and the vehicle engine/fuel systems often leads to co-benefits when 
technology is added or upgraded. In some cases technology to meet one 
of the new or revised evaporative emission requirements will either 
help in efforts to meet other evaporative type requirements or enhance 
durability. For example, technology used to address the canister bleed 
standard will also reduce hot soak plus diurnal emissions and 
technology to meet the leak standard will reduce hot soak plus diurnal 
emissions and enhance durability.
    Based on review of current certification data and the documentation 
in current professional literature, there is no doubt that the 
technology is available to meet the final evaporative emission 
standards described in this rule.\358\ There are at least 50 vehicle 
models which met the requirements in 2013.\359\ There are many 
technologies manufacturers can consider which will reduce emissions and 
enhance durability. Manufacturer compliance options and cost 
considerations are also addressed by the phase-in flexibilities and as 
the ABT program.
---------------------------------------------------------------------------

    \358\ Passavant, G. (December 2013). Assessment of 2013 MY 
Evaporative Emission Results. Memorandum to the docket.
    \359\ See Chapter 1 of the RIA for more detail.
---------------------------------------------------------------------------

    In the NPRM we described a variety of technology approaches and 
calibrations which manufacturers could use to meet the Tier 3 
evaporative emission requirements. No comments were provided on the 
stringency of the standards, the technologies, the feasibility of the 
standards, or the costs of compliance. Nonetheless, we updated our 
technology analysis in light of new certification data and vehicle 
technology projections. As in the analysis supporting the NPRM, we 
identified technologies on the basis of their control effectiveness and 
cost to implement. Not every model will use every technology described 
below. Rather we expect manufacturers to apply the technologies needed 
on any given model to meet the compliance target level. The 
technologies could be broadly grouped into two segments. The

[[Page 23506]]

first are those expected to see widespread use based on their 
effectiveness and cost to implement. The second are those which are in 
relatively widespread use today, but could be optimized if necessary to 
achieve further reductions. In many cases the reductions available from 
this second group are relatively small and the costs are slightly 
higher than for the other strategies. The anticipated control 
technologies to comply with the hot soak plus diurnal, canister bleed/
rig, and leak standards are described briefly below and are grouped in 
these two basic segments. A more detailed analysis for each vehicle 
category is found in Chapter 1 of the Regulatory Impact Analysis (RIA).
    a. Technologies expected to see widespread use: Engine/fuel system 
conversion: As projected in our RIA for the 2017-2025 light-duty GHG 
emissions final rule, EPA projects a significant movement from port 
fuel injection (PFI) engines to gasoline direct injection (GDI) 
engines. This ranges from 60-100 percent of products for all categories 
except gasoline-powered trucks over 14,000 lbs GVWR. This reduces air 
induction systems emissions by 90 percent.
    Air Induction System (AIS) Scrubber: For vehicles/engine models not 
converted to GDI, EPA projects the use of an AIS scrubber as is now 
used on some PZEV models. These would reduce air induction system 
emissions by 85 percent.
    Canister honeycomb: This is a lower gasoline working capacity 
activated carbon device designed to load and purge very easily and 
quickly. This device reduces canister bleed emissions by 90 percent but 
also provides control for the hot soak plus diurnal test.
    Reduce leaks from connections and improve seals and o-rings: Vapor 
leaks from connections and the emission rates from these leaks is 
exacerbated if poor sealing techniques or low grade seal materials are 
use in connectors such as o-rings. Reducing connections in the fuel and 
evaporative systems and improving techniques and materials would reduce 
these emissions by 90 percent. This would reduce hot soak plus diurnal 
emissions, improve durability, and help to assure compliance with the 
leak standard.
    Move parts into the fuel tank: Another means to reduce leak-related 
vapor emissions is to move fuel evaporative system parts which are 
external to the fuel tank to the inside. Emissions from these parts 
would be completely eliminated. This would reduce hot soak plus diurnal 
emissions, improve durability, and help to assure compliance with the 
leak standard.
    OBD evaporative system leak monitoring: Beginning in the 2017 model 
year, the OBD system will need to be able to find, confirm, and signal 
a leak in the evaporative system of 0.020 inches cumulative diameter or 
greater. This is currently done on most vehicles less than 14,000 lbs 
GVWR as a result of the manufacturers' response to meeting CARB 
requirements, but will be mandatory under EPA regulations.
    b. Technologies expected to be optimized if necessary to achieve 
further reductions:
    In the NPRM, EPA discussed a number of other technologies with the 
demonstrated potential to further reduce evaporative emissions. These 
included: (1) Upgrading the activated carbon canister and optimizing 
purge calibrations (especially for larger displacement engines), (2) 
upgrading fuel line materials to reduce permeation, (3) improving the 
fuel tank barrier layer to reduce permeation, (4) improving fuel tank 
manufacturing processes to reduce tank seam permeation emissions, (5) 
upgrading the fuel tank fill tube material to reduce permeation, and 
(6) improving the security of the fill tube connection to the fuel 
tank. While each of these approaches reduces evaporative emissions, 
they are to large degrees in use today. Thus their further application 
may be limited to specific situations. It is worth noting, that the use 
of these technologies has contributed to the relatively large 
compliance margins under the existing hot soak plus diurnal standards.
    The reductions required and cost of compliance for any given 
vehicle model will depend on its current certification level and the 
type of evaporative emission control technology applied. The baseline 
emission values for 2-day hot soak plus diurnal evaporative emission 
certification for current models range from 0.42-0.96 grams per test 
(g/test). Achieving the desired compliance targets (at least 25 percent 
below the Tier 3 standard) would require reductions ranging from 0.12 
g/test for LDT2s to 0.51 g/test for HDGVs.\360\ EPA estimates 2025MY 
costs in the range of $9-15 per vehicle with a fuel cost savings of 
about $2 over the vehicle life. The application of the technologies 
expected to see widespread use under Tier 3 will create the margins 
need for compliance and in some cases create excess reductions which 
could be used to generate credits for ABT.
---------------------------------------------------------------------------

    \360\ Passavant, G. (December 2013). Assessment of 2013 MY 
Evaporative Emission Results. Memorandum to the docket.
---------------------------------------------------------------------------

4. Heavy-Duty Gasoline Vehicle (HDGV) Requirements
a. Background on HDGV
    HDGVs are gasoline-powered vehicles with either a GVWR of greater 
than 8,500 lbs, or a vehicle curb weight of more than 6,000 lbs, or a 
basic vehicle frontal area in excess of 45 square feet.\361\ HDGVs are 
predominantly but not exclusively commercial vehicles, mostly trucks 
and other work type vehicles built on a truck chassis. EPA often 
discusses HDGVs in three basic categories for regulatory purposes 
according to their GVWR class. These are Class 2b (8,501-10,000 lbs 
GVWR), Class 3 (10,001-14,000 lbs GVWR), and Class 4 and above (over 
14,000 lbs GVWR). These are further sub-categorized into complete and 
incomplete vehicles.\362\ Class 2b HDGVs are mostly produced by the 
manufacturers as complete vehicles and are very similar to lower GVWR 
LDTs of the same basic model sold by the manufacturers. Class 3 HDGVs 
are also built from LDT chassis with fuel system designs that are 
similar to their Class 2b and LDT counterparts, but these are on some 
occasions sent to secondary manufacturers as incomplete vehicles to 
attach a load carrying device or container. EPA estimates that more 
than 95 percent of Class 2b/3 vehicles are complete when they leave the 
original equipment manufacturer (OEM). Class 4 and above HDGVs are 
built on a more traditional heavy-truck chassis and in most cases leave 
the OEM as an incomplete vehicle. For Class 2b/3 vehicles, it is common 
to certify the vehicle for emissions purposes (exhaust, evaporative, 
etc) as a full chassis, while for Class 4 and above the vehicle is 
certified as a chassis for evaporative emissions while the engine is 
dynamometer certified for exhaust emissions.
---------------------------------------------------------------------------

    \361\ MDPVs also meet the definition of HDVs, but they are 
classified separately for evaporative and refueling emission 
purposes. See 40 CFR 86.1803-01.
    \362\ Heavy-duty vehicles may be complete or incomplete. A 
complete HDGV is one that has the primary load carrying device or 
container (or equivalent equipment) attached, normally by the 
vehicle OEM. An incomplete vehicle is one that does not have the 
primary load carrying device or container (or equivalent equipment) 
when it leaves control of the manufacturer of the engine.
---------------------------------------------------------------------------

    HDGVs have been subject to evaporative emission standards since the 
mid 1980s. Recently, the timing of the standards has lagged 
requirements for LDVs and LDTs by several years, but the standards are 
of comparable stringency when vehicle size and fuel

[[Page 23507]]

tank volume are considered. The most recent 2/3 day hot soak plus 
diurnal standards for HDGVs took effect in 2008. Refueling control 
requirements apply to complete Class 2b vehicles only. These 
requirements phased-in over the period from 2004-2006.
b. HDGV Evaporative Emission Control Requirements
    As discussed above, EPA is including HDGVs within the Tier 3 
evaporative emissions program. The hot soak plus diurnal and canister 
bleed test emission standards that will apply to these HDGVs are 
presented in Table IV-19 and-Table IV-20 and the high altitude standard 
is presented in Table IV-21. These vehicles will be included in the 
averaging calculation beginning in the 2018 MY and will be eligible for 
creating and using allowances and credits.
    Furthermore, for the reasons discussed below, EPA is requiring that 
all complete HDGVs regardless of their GVWR be required to meet the 
refueling emission standards and use the test procedures currently 
required for LDVs and LDTs and complete Class 2b vehicles. (See Sec.  
86.1813-17). In their comments, manufacturers expressed concern about 
the amount of gasoline used in the development and certification of 
refueling emission control systems for HDGVs (due to the larger fuel 
tanks). To address this concern, EPA will permit manufacturers to 
certify using two separate processes for vehicles with tanks of 40 
gallons or larger. The first will be the engineering evaluation of 
canister and purge data from lighter weight HDGVs certified in the SHED 
to show that similar or scaled-up systems on heavier HDGVs have the 
purge volume and canister working capacity to pass the refueling 
standard. This could include a comparison of control system design 
elements such as canister shape, canister internal architecture, total 
canister volume, and total gasoline working capacity as well as purge 
air volume over the Federal Test Procedure. This would be subject to 
the application of good engineering judgment. The second is application 
of the provisions of 40 CFR 86.153-98 (a) through (b)(1) on a bench set 
up for a tank of the appropriate volume in lieu of a vehicle test to 
show the efficacy of the fill neck seal. Such a test could be conducted 
in a conventional SHED.
    The ORVR requirement applies to complete Class 3 vehicles by the 
2018MY and all other complete HDGVs by the 2022MY. EPA proposed these 
requirements for Class 3 HDGVs and asked for comment on extending the 
requirements to all HDGVs. The manufacturers expressly commented that 
HDGV ORVR requirements should be limited to complete HDGVs.\363\ There 
are only four manufacturers of HDGVs. Of these, three offer complete 
products in the Class 3 weight range and none offer complete products 
in the Class 4 and above weight range. As mentioned above, Class 3 
vehicles have largely the same vehicle chassis and fuel system 
configurations as Class 2b vehicles. The manufacturers of complete 
Class 2b vehicles indicated to the CARB and EPA that they carry across 
their Class 2b fuel evaporative control system designs onto Class 3 and 
this includes the onboard refueling vapor recovery (ORVR) system used 
for control of refueling emissions. Thus, applying refueling emission 
controls to complete Class 3 vehicles adds no cost and has little 
additional emission reduction benefit. However, it does set a 
requirement to continue these controls in future model years. There are 
no complete Class 4 and above HDGVs and neither manufacturer who 
certifies incomplete HDGVs above 14,000 lbs GVWR objected to 
establishing an ORVR requirement for complete HDGVs.\364\ This sector 
is made of incomplete HDGV chassis and diesel-powered products. 
However, setting a requirement for potential future Class 4 and above 
designs establishes certainty for manufacturers but brings no near term 
cost burden or emission reductions.
---------------------------------------------------------------------------

    \363\ See comments of Alliance of Automobile Manufacturers and 
Association of Global Automakers in the public docket at EPA-HQ-OAR-
2011-0135-4451.
    \364\ Passavant, G., (September 2013). EPA and General Motors 
Meeting on Issues Related to Tier 3 NPRM and (September 2013). EPA 
and Ford Meeting on Issues Related to Tier 3 NPRM. Memorandums to 
the docket.
---------------------------------------------------------------------------

    Incomplete HDGVs make up 15-20 percent of all HDGV sales. Of this, 
approximately 80 percent are Class 2b/3 and 20 percent are Class 4 and 
above. EPA is not extending the refueling emission control requirement 
to incomplete HDGVs at this time. The control system designs would be 
essentially the same as on complete HDGVs, but manufacturers have 
indicated to EPA that they would have to establish additional measures 
to ensure that the steps taken to complete the vehicle by the secondary 
manufacturer do not compromise the integrity and safety of the fuel/
evaporative control system (including ORVR) and that the ORVR system 
continues to perform properly with regard to emissions control. While 
there are relatively few of these vehicles, their contributions to the 
inventory are larger than might be expected due to their lower fuel 
economy. Given these contributions, EPA may consider proposing to apply 
ORVR to incomplete HDGVs in a future action.
    EPA is also including a provision that manufacturers be permitted 
to comply with the refueling emission standard as early as the 2015 MY 
to earn on a one-to-one basis allowances which could be used to phase-
in the Class 3 refueling emission control requirement or as an 
allowance on a 2:1 basis under the Tier 3 evaporative emission program. 
EPA believes this is appropriate since the expected daily average 
reduction in vehicle refueling emissions for this class of vehicles is 
large relative to the reduction in evaporative emissions expected under 
Tier 3. This would also apply to any incomplete HDGV a manufacturer 
voluntarily certified to the refueling emission standards. Any 
certifications, including those done early, must use EPA Tier 3 test 
procedures and certification test fuels or CARB LEV III equivalents.
c. Other Program Elements for HDGVs
    In the NPRM, EPA sought comment on several provisions related to 
Tier 3 certification test fuel and evaporative emission control 
requirements.
    First, EPA sought comment on whether heavy-duty gasoline engines 
(HDGEs) not subject to new Tier 3 exhaust emission standards (those 
certified for exhaust emissions using an engine dynamometer) which are 
used in HDGVs subject to Tier 3 evaporative emission standards should 
certify for exhaust emissions on Tier 3 emissions test fuel.\365\ 
Manufacturers responded by asking that the use of Tier 3 fuel for HDGE 
exhaust emissions certification be voluntary, but agreed that the use 
of Tier 3 certification fuel would not change the stringency of the 
current dynamometer-based emission standards or the costs of 
compliance. Based on consultations with manufacturers, EPA has decided 
to require that all HDGEs be certified on Tier 3 fuel by the 
2022MY.\366\ To provide flexibility for very unique applications or 
circumstances, EPA will allow up to five percent of a manufacturer's

[[Page 23508]]

dynamometer-certified HDGE sales in any given model year to be 
certified using Tier 2 certification fuel. This flexibility is limited 
to certification based on carryover data beginning in the 2022MY.
---------------------------------------------------------------------------

    \365\ EPA also sought comment on whether to require HDGVs to use 
Tier 3 emissions test fuel for evaporative emissions standards even 
if we did not adopt the proposed Tier 3 evaporative emission 
standards and whether to allow Class 4 and above HDGVs to earn 
allowances or credits if EPA did not adopt the Tier 3 standards for 
these vehicles. These have been superseded by our decision to apply 
the Tier 3 evaporative emission standards to all HDGVs as described 
above.
    \366\ Passavant, G. (September 2013). EPA and General Motors 
Meeting on Issues Related to Tier 3 NPRM and (September 2013). EPA 
and Ford Meeting on Issues Related to Tier 3 NPRM. Memorandums to 
the docket.
---------------------------------------------------------------------------

    Second, as discussed in Section IV.F.5 for light-duty vehicles, we 
are committed to the principle of ensuring that any change in test fuel 
for heavy-duty gasoline vehicles/engines will not affect the stringency 
of either the fuel consumption or GHG emissions standards. As part of 
the separate rulemaking discussed in Section IV.F.5, we expect to 
establish the appropriate test procedure adjustment for HD engine fuel 
consumption standards and to determine the need for any test procedure 
adjustment for GHG emissions standards based on the change in 
certification test fuels.
    Third, to simplify the evaporative emission regulations for HDGVs 
and to bring them more in line with the current structure of the 
product offerings in this sector, we are finalizing provisions to 
permit evaporative emissions certification by engineering analysis for 
vehicles above 14,000 lbs GVWR (instead of above 26,000 lbs GVWR as 
permitted in the existing regulations). We are also finalizing 
regulatory language to clarify how these provisions are to be 
implemented. This applies to the hot soak plus diurnal, running loss, 
and canister bleed standards. These HDGVs will remain subject to the 
emission standards when tested using the specified procedures. This is 
the same cut point allowed by CARB and will allow for one certification 
method. Even though it was supported by one commenter, we are not 
including specific provisions for design-based certification for HDGVs 
over 14,000 lbs GVWR. EPA believes that the option to certify using 
engineering analysis and data serves the same purpose.
    Fourth, we are finalizing a revised description of evaporative 
emission families that does not reference sealing methods for 
carburetors or air cleaners as this technology is now obsolete for 
HDGEs.
    Fifth, EPA is finalizing regulatory language permitting HDGVs over 
14,000 lbs GVWR to be grouped with those between 10,001 and 14,000 lbs 
GVWR for purposes of complying with evaporative and refueling emission 
control standards and related provisions. In these cases, we require 
these HDGVs to meet all the requirements applicable to the group in 
which they are being included (e.g., useful life, OBD, etc.).
    Finally, the regulations at 40 CFR part 86, subpart M, describe how 
to test heavy-duty vehicles above 14,000 lbs GVWR to demonstrate 
compliance with evaporative emission standards. Most of these 
provisions are identical to those that apply under 40 CFR part 86, 
subpart B. We are eliminating subpart M and replacing it with a simple 
instruction to test these heavy-duty vehicles using the procedures of 
subpart B, with a small number of appropriate modifications noted as 
exceptions to the light-duty test procedures. Relying on references to 
subpart B instead of largely copying them into subpart M eliminates 
many pages of unnecessary regulatory text and makes it easier to 
maintain a consistent set of requirements. Changing a provision in 
subpart B in the future will automatically apply for evaporative 
testing of both light-duty and heavy-duty vehicles unless otherwise 
provided in the particular rulemaking.
    In response to comments received, we are specifying that heavy-duty 
vehicles above 14,000 lbs GVWR must use the same drive schedules and 
test fuels that apply for light-duty vehicles. Subpart M already allows 
light-duty drive schedules and certification test fuels as an 
alternative to using those for heavy-duty vehicles, and most if not all 
manufacturers of these vehicles already use the light-duty drive 
schedules, which facilitates testing simplicity and coordination of 
design parameters with light-duty vehicles. The heavy-duty drive 
schedule generally involves less driving, which makes this the more 
stringent test option for designing purge. Omitting this more stringent 
option therefore does not change the effective stringency of the 
applicable standards.
    With these changes from the proposed rule, there are only two 
aspects of testing that are different for heavy-duty vehicles above 
14,000 lbs GVWR. First, the regulations specify that the exhaust 
emission measurements are not required for the driving portion of the 
test between canister pre-conditioning and diurnal testing. Exhaust 
emission standards in this vehicle size range apply based on engine 
testing only. Second, wider engine speed tolerances apply. This is 
captured in part 1066 by specifying wider engine speed tolerances for 
any testing that does not require exhaust emission measurements since 
the greater allowance has no effect on emissions measurements. This 
applies, for example, for pre-conditioning drives for light-duty 
vehicles, and it also applies for pre-conditioning related to 
evaporative emissions of heavy-duty vehicles above 14,000 lbs GVWR.
    There are some differences in the existing test provisions in 
subparts B and M that we are not preserving. Some of these differences 
arose from changes to subpart B that were inadvertently not carried 
over to subpart M. In other cases, there may have been an intentional 
distinction that no longer applies (such as provisions related to 
slippage on twin-roll dynamometers). Also, we are not retaining 
distinctions in subpart M related to procedures for determining road 
load settings and for operating manual or automatic transmissions. 
Additional differences we are not preserving include gas divider 
specifications, SHED and dynamometer calibration procedures, and some 
provisions for alternative canister loading and vehicle pre-
conditioning. We are also restoring the content of Sec.  86.1235(b) 
through (i) related to dynamometer operating procedures, which were 
inadvertently removed in an earlier rulemaking.
5. Evaporative Emission Requirements for FFVs
    A flexible fuel vehicle (FFV) as defined in 40 CFR 86.1301-01 means 
any motor vehicle engineered and designed to be operated on a petroleum 
fuel and on a methanol or ethanol fuel or any mixture of the petroleum 
fuel and methanol or ethanol. Many manufacturers have one or more FFVs 
in their product offerings. These include many different LDV and LDT 
vehicle chassis styles including passenger cars, mini-vans, pick-ups, 
sport utility vehicles and even a few HDGVs.
    The EPA regulations implementing the FFV provisions for ethanol 
FFVs, including those in 40 CFR 86.1811-04 and 86.1811-09, have been 
applied primarily for FFVs capable of operating on gasoline/ethanol 
mixtures up to E85. As a matter of policy, EPA has not required 
certification testing for evaporative and refueling emissions on the 
full range of E0-E85 fuel blends, but instead has allowed the option to 
use a blend created when Tier 2 fuel (9 RVP E0) is splash blended with 
ethanol to a 10 percent gasoline/ethanol blend. This simulates what 
often occurs in the vehicle fuel tank when Tier 2 fuel (9 RVP E0) is 
dispensed into a tank containing mostly E85. This yields a blend which 
has a Reid vapor pressure of about 10 psi. Nearly all manufacturers 
have certified using this option. The California ARB LEV III program 
has no special evaporative or refueling emission test fuel requirements 
for FFVs.
    In the Tier 3 NPRM, EPA proposed to revise the certification test 
fuel for evaporative emissions, to revise the hot soak plus diurnal 
emission standard, and to add a canister bleed emission standard and a 
leak standard. These

[[Page 23509]]

standards apply to FFVs and non-FFVs. EPA proposed to revise the 
ethanol content of the certification test fuel for refueling emissions 
but did not otherwise propose to change the fuel vapor pressure, the 
level of the refueling emission standard or the test procedure. 
Furthermore, in the NPRM, EPA sought comment on leaving unchanged the 
basic approach to FFV certification test fuel for Tier 3 evaporative 
and refueling emissions, except that the certification test fuel would 
be 9 RVP E0 splash blended with E15 such that the blend would have a 10 
psi vapor pressure, i.e., the RVP of the evaporative emissions test 
fuel used by nearly all manufacturers. Manufacturers commented that the 
Tier 3 certification test fuel should be the same for FFVs and non-FFVs 
and that carryover should be permitted from Tier 2 to Tier 3. EPA met 
with several manufacturers to clarify their comments and to discuss 
issues affecting the evaporative and refueling emissions certification 
fuel for FFVs.\367\
---------------------------------------------------------------------------

    \367\ Passavant, G. (September, 2013). EPA, GM, Ford, and 
Chrysler Meeting on Tier 3 Certification Fuel for Evaporative and 
Refueling Emission Standards for FFVs. Memorandum to the docket.
---------------------------------------------------------------------------

    For FFVs, EPA has several factors to consider for evaporative and 
refueling emission certification test fuel. First, EPA is finalizing a 
9 RVP E10 certification test fuel for non-FFVs for evaporative and 
refueling emissions. This is consistent with our broader policy 
objective to allow the manufacturers to sell the same vehicles in all 
50 states. Second, 10 psi RVP certification test fuel for the Tier 3 
evaporative emission standards for FFVs could result in more 
evaporative emission reductions than a 9 psi RVP test fuel, but this 
would be counter to the broader policy objective regarding a national 
program since CARB has no separate FFV evaporative emission standards 
and likely would affect the stringency of the final evaporative 
emission standards. Specifically, finalizing 10 psi RVP certification 
test fuel for the Tier 3 evaporative emission standards as applied to 
FFVs would increase the stringency of the evaporative emission 
standards for FFVs both compared to the Tier 3 evaporative emission 
standards with 9 psi RVP test fuel for non-FFVs and compared to the 
Tier 2/MSAT evaporative emission standards with 10 psi RVP test fuel 
for FFVs. Third, we are not changing the level of the refueling 
emission standard (though we are adding ethanol to the test fuel and 
extending ORVR to complete Class 3 HDGVs) and we did not examine how a 
potential change from the existing 10 psi RVP test fuel for FFV 
refueling would affect in-use emission reductions or the stringency of 
the refueling standard for FFVs. A change in the test fuel vapor 
pressure likely would likely lead to a change in the stringency of the 
refueling emission standard as they are now applied to FFVs. Retaining 
the current requirements for refueling emissions for FFVs does not 
affect the national program since CARB currently follows Federal Test 
Procedures and test fuels for ORVR.
    Balancing all of these factors, EPA is adopting a bifurcated scheme 
for evaporative and refueling emission certification for Tier 3. 
Evaporative emission requirements for the hot soak plus diurnal, 
canister bleed, running loss, spit back, and leak standards will be 
based on Tier 3 certification fuel (9 RVP E10) for FFVs. This will 
permit reciprocity between the LEVIII and Tier 3 evaporative emission 
standards programs and subject the manufacturers to only one set of 
evaporative emission tests for FFVs and non-FFVs. However, for the 
refueling emission standard, EPA is retaining the 10 psi certification 
test fuel requirement for FFVs because the worst case in-use RVP 
conditions when E0 and E85 are commingled will still be possible. In 
current systems, the fuel vapor pressure in the refueling emission test 
drives the total gasoline working capacity of the activated carbon 
canister that is necessary in the integrated evaporative/refueling 
control system. Although a 10 psi RVP certification fuel for 
evaporative emissions control could be viewed as more stringent, we 
believe that keeping the fuel vapor pressure at 10 psi in the refueling 
test, which is what was proposed for comment, will help to assure that 
the in-use emission reduction benefits of current evaporative systems 
on FFVs are retained. We expect that total canister gasoline working 
capacities will still be driven by the 10 psi RVP fuel used in the 
refueling test and therefore the higher in-use RVP conditions which 
impact evaporative emissions will still be addressed.
    EPA is specifying a 10 RVP E10 test fuel specification for FFV 
refueling emissions certification. However, as a compliance alternative 
EPA will continue to permit certification based on in vehicle fuel tank 
blending of two different fuels (i.e., vehicle fuel tank filled to 10 
percent of capacity with E85 and then refueled to at least 95 percent 
of capacity with (9 RVP E0). Either of these approaches will also meet 
CARB certification test fuel requirements as the test fuel vapor 
pressure would be higher than with EPA's 9 RVP E10 or CARB's 7 RVP E10 
test fuel. In addition, we are not changing existing requirements that 
all IUVP testing for evaporative and refueling tests are done on the 
non-FFV fuel (i.e., Tier 2 IUVP vehicles are tested on 9 RVP E0 and 
Tier 3 IUVP vehicles are tested on 9 RVP E10.
    In their comments on the Tier 3 NPRM, manufacturers asked that EPA 
allow carryover of certification emission data from Tier 2 to Tier 3. 
Since the regulatory approach for refueling emissions is basically the 
same as what is currently being used by the manufacturers, we believe 
there should be opportunity for carryover of refueling emission data 
under the current regulatory program. Manufacturers also expressed 
concern that the refueling emission standard would require them to keep 
a 10 RVP E10 or 9 RVP E0 test fuel solely for refueling emission 
standard certification purposes. To help address this concern, in 
certification testing, EPA would consider approving other refueling 
test fuel blends with 10 percent ethanol and 10 psi such as a refueling 
event where a tank is filled initially with 10 percent E85 and during 
refueling test is filled with 90 percent 9 RVP E0. EPA would also 
permit manufacturers the option to seek EPA approval to certify by 
attestation using alternative procedures or through engineering 
analysis based on similar evaporative/refueling emission system 
configurations and emission test results and data on similar vehicles 
showing that the vehicle could pass the refueling emission standard and 
meet the requirements in use on 10 psi RVP E10 fuel. They would remain 
subject to confirmatory testing on 10 RVP E10. Both of these options 
could only be implemented with approval of the Administrator.
6. Test Procedures and Certification Test Fuel
a. Review and Update of Testing Requirements
    EPA adopted the current test requirements for controlling 
evaporative emissions in 1993.\368\ Those changes included: (1) Diurnal 
testing based on heating and cooling the ambient air in the SHED \369\ 
instead of forcing fuel temperatures through a specified temperature 
excursion; (2) repeated 24-hour diurnal measurements to capture both 
permeation and diurnal emissions; (3) high-temperature hot soak 
testing; (4)

[[Page 23510]]

high-temperature running-loss measurements with a separate standard, 
including controlled fuel temperatures according to a fuel-temperature 
profile developed for the vehicle; and (5) canister preconditioning to 
ensure that vehicles could effectively create canister capacity to 
prepare for several days of non-driving.
---------------------------------------------------------------------------

    \368\ 58 FR 16002 (March 24, 1993).
    \369\ SHED is the Federal Register acronym for sealed housing 
for evaporative determination. The SHED is the enclosure in which 
the evaporative emissions are captured before measurement.
---------------------------------------------------------------------------

    These test procedures are generally referred to as ``enhanced 
evap'' testing. EPA adopted these ``enhanced evap'' test procedures in 
coordination with CARB. The test requirements include two separate test 
sequences to demonstrate the effectiveness of evaporative emission 
controls. The ``2-day sequence'' involves canister loading to two-gram 
breakthrough, followed by driving for the exhaust test (about 31 
minutes), a hot soak test, and two days of cycled ambient temperatures. 
The ``3-day sequence'' involves canister loading with 50 percent more 
vapor than needed to reach breakthrough, followed by driving for the 
exhaust test, driving for the running loss test (about 97 minutes 
total), a high-temperature hot-soak test, and three days of cycled 
ambient temperature.
    The 2-day sequence was intended primarily to insure a purge 
strategy which would create enough canister capacity to capture two 
days of diurnal emissions after limited driving. The two-day 
measurement period is also effective for requiring control of 
permeation and other fugitive emissions. The 3-day sequence was 
intended to establish a design benchmark for achieving adequate 
canister storage capacity to allow for several days of parking on hot 
summer days, in addition to requiring vehicle designs that prevent 
emissions during high-temperature driving and shutdown conditions.
    After adopting these evaporative test procedures, we set new 
standards for refueling emissions control which called for onboard 
refueling vapor recovery (ORVR).\370\ Manufacturers have typically 
designed their ORVR systems to be integrated with their evaporative 
controls, using a single canister and purge strategy to manage all fuel 
vapors vented from the fuel tank. Due to the magnitude of the refueling 
emission load and the manner in which the load rates affect activated 
carbon capture efficiency, it has become clear that ORVR testing with 
these integrated systems serves as the benchmark for achieving adequate 
canister storage capacity.
---------------------------------------------------------------------------

    \370\ 59 FR 16262 (April 6, 1994).
---------------------------------------------------------------------------

    In the nearly 20 years since adopting these test procedures, 
manufacturers have made great strides in developing designs and 
technologies to manage canister loading and purging and to reduce 
permeation emissions. Except as discussed below, we are not changing 
the test procedures for demonstrating compliance with the Tier 3 
emission standards. As described above, we are adopting a new standard 
based on measured values over a canister bleed test, and a fuel system 
rig test. These are intended to measure only fuel vapors which diffuse 
from the evaporative canister or permeate/leak from a fuel system. CARB 
developed these procedures as a means for setting standards that are 
not affected by nonfuel background emissions. The canister bleed test 
procedure is a variation of the established two-day test sequence. The 
canister is preconditioned by purging and loading to breakthrough, then 
attached to an appropriate test vehicle for driving over the duty cycle 
for the exhaust test. The canister is then attached to a fuel tank for 
measurement. After a stabilization period, the tank and canister 
undergo two days of temperature cycling. Canister emissions are 
measured using a flame ionization detector (FID), with a conventional 
SHED approach or by collecting emissions in a bag and measuring the 
mass. Rather than repeating CARB's regulations, we are incorporating 
those regulations by reference into the CFR.\371\ This will avoid the 
possibility of complications related to minor differences that may 
occur with separate test procedures. The fuel system rig test is a 
bench test where a complete vehicle fuel system (without the vehicle 
chassis) is constructed in the SHED and evaluated over the 3-day cycle 
in both a ``wet'' and ``dry'' state.\372\
---------------------------------------------------------------------------

    \371\ For a description of the canister bleed test procedure 
(BETP), see pp.III-51 to III-55 of http://www.arb.ca.gov/db/search/search_result.htm?cx=006180681887686055858%3Abew1c4wl8hc&cof=FORID%3A11&q=BETP&siteurl=http%3A%2F%2Fwww.arb.ca.gov%2Fhomepage.htm (last accessed 
on January 13, 2014).
    \372\ See http://www.arb.ca.gov/msprog/macs/mac0503/mac0503.pdf 
for a description of the rig test standard and test procedure (last 
accessed on January 13, 2014).
---------------------------------------------------------------------------

    CARB adopted the fuel system ``rig test'' as an optional approach 
to demonstrate control of evaporative emissions without the effects of 
the nonfuel hydrocarbon emissions that are seen in testing the whole 
vehicle in the SHED. We generally expect manufacturers to comply with 
the EPA requirements which include the canister bleed test and emission 
standard instead of CARB LEV III Option 1 which includes the rig test 
and emission standard. However, since we are accepting PZEV zero evap 
and CARB LEV III Option 1 certifications for the 2017-2018 MYs and 
2017-2021 MYs, respectively, we are also incorporating by reference 
CARB's rig test into the CFR to accommodate those manufacturers that do 
in fact rely on this approach.
    Also, as discussed further below, we are adopting a new leak test 
procedure which will be used to measure leak rates for the leak 
standard. The leak test standard test procedure is contained in the 
regulatory text.
    Manufacturers have raised a pair of related concerns regarding the 
current test procedures. First, hybrid vehicles and new engine designs 
for meeting fuel economy standards and CO2 emission 
standards increase the challenge of maintaining an adequate purge 
volume to prepare vehicles for the diurnal test. For hybrid vehicles 
this is related to the amount of time the engine is running. For other 
technologies this is related to the trend toward decreasing available 
vacuum in the intake manifold, which is the principal means of drawing 
purge air through the canister. Second, preconditioning the canister by 
loading to breakthrough serves as a disincentive for some control 
strategies that might otherwise be effective at reducing emissions, 
such as designs involving greater canister capacity or better 
containment of fuel vapors inside the fuel tank. In addition, we have 
learned from studying in-use emissions and in-use driving behaviors and 
usage patterns that it is not uncommon for vehicles to go for an 
extended period with little or no opportunity to purge the canister.
    In the NPRM, we requested comment on an optional adjustment to the 
test procedure intended to address these three concerns. In this 
alternative, for designs involving pressurized tanks, manufacturers 
would determine an alternative vapor load to precondition the canister 
before the exhaust test. If, for example, a fuel system is designed to 
stay sealed up to 1 psi and to vent vapors to the canister if rising 
temperatures trigger a pressure-relief valve, the manufacturer could 
quantify the actual vapor load to the canister during three consecutive 
days of cycling through diurnal test temperatures. This three-day vapor 
load would be the amount of fuel vapor used to precondition the 
canister (loaded at the established rate of 15 grams per hour). This 
canister loading may also involve butane instead of fuel vapor, but we 
would likely require a greater mass of butane to account for the fact 
that it is easier to remove the butane from the activated carbon in the 
canister. This

[[Page 23511]]

approach would be flexible to accommodate any design target for 
pressurizing fuel tanks. Canister preconditioning for the ORVR test 
(for integrated and nonintegrated systems) would remain unchanged. EPA 
sees merit in further consideration of such test procedure 
flexibilities, but auto manufacturers did not provide support these 
concepts in their comments and we are not adopting the proposed 
optional adjustment.
b. Test Fuel for Certification
    EPA is changing the certification test fuel specifications as 
described in Section IV.F. Here we discuss some implications for 
evaporative and refueling emissions testing beyond those discussed 
above for FFVs. We are revising the certification test fuel 
specification in conjunction with the Tier 3 standards, principally to 
include ethanol and reduce sulfur such that the test fuel better aligns 
with the current and projected in-use fuel. Although we received 
unsolicited comment asking that we set durability test fuel 
specifications for evaporative and refueling emission control systems 
to be the same as those for the certification test fuel (9 RVP E10 in 
this final rule), we are not changing durability fuel specifications in 
this rule other than to remove minimum sulfur content requirements. In 
particular, we are not changing the existing requirement that ``any 
mileage accumulation method for evaporative emissions must employ 
gasoline fuel for the entire mileage accumulation period which contains 
ethanol in, at least, the highest concentration permissible in gasoline 
under federal law and that is commercially available in any state in 
the United States''. See Sec. Sec.  86.1824-08(f)(1) and 86.113-
04(a)(3)(i). EPA believes this is prudent policy to ensure that 
emission control systems are designed for the fuels with the potential 
to adversely affect durability and there is no reason to change the 
existing approach especially since E15 fuel is now legally permissible 
and commercially available for appropriate vehicles and there is 
potential for its market penetration to increase in the future. Any 
bench aging using E15 fuel must simulate the effects of alcohol in-use 
fuels on evaporative emission system components.
    Since there are already vehicles in the market which employ the 
technology needed to meet the new hot soak plus diurnal requirements, 
EPA is taking a flexible approach to the phase-in of the certification 
test fuel. This is summarized in Table IV-22.
    To accommodate vehicles already designed to meet CARB PZEV zero 
evap evaporative emission requirements, EPA's phase-in provides that 
PZEV zero evap vehicles which qualify for carryover can use CARB Phase 
2 fuel for evaporative emissions (hot soak plus diurnal and running 
loss standards) and rig test certification for MYs 2015-2019. For CARB 
PZEV zero evap vehicles, high altitude, refueling, and spit back 
standard certification may use either EPA Tier 2 or Tier 3 fuel in MYs 
2015-2019. For the leak standard in the 2018 and later MYs, they must 
use Tier 3 test fuel. Beginning in the 2017 MY, the use of PZEV zero 
evap data is limited to carryover of data from 2015 or 2016 MY 
certifications.
    Those using CARB LEV III Option 1 can use CARB Phase 3 fuel for 
evaporative emissions (hot soak plus diurnal and running loss 
standards) and rig test certification for MYs 2015-2021. For CARB 
Option 1, high altitude, refueling, and spit back standard 
certification must may use Tier 2 or Tier 3 fuel in MYs 2015-2016 but 
in the 2017 and later MYs all LEV III option 1 certifications for the 
high altitude, refueling, spit back, and leak standards must use EPA 
Tier 3 fuel.
    CARB LEV III Option 2 evaporative emission vehicles may use CARB 
Phase 3 fuel to meet evaporative (hot soak plus diurnal and running 
loss standards) and canister bleed standards beginning in 2015 MY and 
following. High altitude, refueling, and spit back may use Tier 2 or 
Tier 3 fuel in model years 2015 and 2016. For 2017 and later model 
years CARB LEV III option 2 evaporative families must use Tier 3 test 
fuel for high altitude, refueling, spit back, and leak standard 
certifications.
    Tier 3 evaporative emission vehicles must use Tier 3 fuel to meet 
evaporative emission (hot soak plus diurnal and running loss 
standards), high altitude, canister bleed, and refueling/spit back 
emission standards beginning in the 2015 MY and following. Beginning in 
the 2018 MY, Tier 3 vehicles must use Tier 3 emission test fuel to 
demonstrate compliance with the leak standard requirements.\373\
---------------------------------------------------------------------------

    \373\ This provision applies in 2017 MY for vehicles meeting the 
Tier 3 requirements using the 20/20 option and does not apply to 
HDGVs with a GVWR greater than 14,000 lbs. Incomplete HDGVs have 
until the 2022 MY to meet the spit back standard.
---------------------------------------------------------------------------

    When the program is fully phased-in, any Tier 3 evaporative 
emission certification will have to use Tier 3 certification test fuel 
and test procedures or CARB equivalent test procedures and fuels. This 
could be done as early as the 2015 MY and will be required for all 
vehicle models by the 2022 MY.\374\ As indicated above and in Table IV-
22, we are further applying the new test fuel at the same time to ORVR 
testing. Therefore, beginning in the 2017 MY if manufacturers do any 
new testing to demonstrate compliance with the Tier 3 evaporative 
emission standards (using Tier 3 or LEV III fuel), they will need to 
submit test data to demonstrate compliance with the refueling emission 
standards using the new certification test fuel as well as the leak 
(when applicable), spit back, canister bleed, running loss, and high 
altitude emission standards. Any family that is not yet captured within 
the Tier 3 phase-in percentage may remain on Tier 2 certification fuel 
through the 2021 MY. By the 2022 MY all evaporative and refueling 
emission certifications will have to be on EPA test procedures and 
certification fuels or CARB equivalents as identified in the 
regulations. Policies regarding test procedures and test fuels for EPA 
confirmatory and other post certification testing are discussed in 
Section IV.C.6.e below.
---------------------------------------------------------------------------

    \374\ The only exception here would be if a vehicle uses 
allowances in the 2022 model year to meet the Tier 3 evaporative 
emission requirements.
---------------------------------------------------------------------------

    Finally, we are including provisions to allow any vehicle certified 
to the refueling spit back standard separately (mostly incomplete 
HDGVs)to continue to do so using Tier 2 current certification fuel 
until the 2022 MY even if its evaporative emissions are certified on 
Tier 3 certification fuel. This is reasonable since the fill quality of 
the vehicle and eliminating spit back are not necessarily related to 
the ethanol or sulfur content of the gasoline. The manufacturers must 
meet this requirement through testing, as the engineering evaluation 
flexibility available for HDGVs over 14,000 lbs GVWR does not apply to 
this standard.
c. Correction for Ethanol Portion of the SHED Measurement
    Another issue related to adding ethanol to the certification test 
fuel relates to the emission measurement in the SHED. Emissions are 
detected by flame ionization detectors (FID), which are less responsive 
to ethanol than gasoline. This effect causes under-reporting from the 
ethanol portion of the fuel vapor. Fuel-related emissions from the 
vehicle may be slightly more weighted toward ethanol than gasoline, 
depending on how the different fuel constituents permeate through 
various fuel-system materials, how they evaporate from the bulk fuel in 
the tank at varying temperatures, and how they adsorb onto and desorb 
from the

[[Page 23512]]

activated carbon in the canister. We proposed to address this issue by 
the use of a prescribed correction factor. Under this approach 
manufacturers would simply multiply their SHED measurement results by a 
fixed value to adjust upward for the difference in the FID response to 
ethanol. Data available to EPA at the time of the NPRM suggested that a 
value of approximately 1.1 would be appropriate for E15.\375\ For an 
E10 certification fuel, California ARB finalized a value of 1.08.
---------------------------------------------------------------------------

    \375\ Moulis, C. (2012, January). SHED FID Responses for 
Ethanol. Memorandum to the docket.
---------------------------------------------------------------------------

    In their comments, the manufacturers supported the use of a 
correction factor, but stipulated that the value put forth by EPA was 
too large and they should be given the option to measure the ethanol 
fraction of the vapor in the SHED through procedures and instrumental 
approaches prescribed in the regulations (see 40 CFR 1065.269, 
1065.369, and 1065.805) instead of using a fixed correction value. Two 
manufacturers provided data based on testing with E10 test fuel which 
generally showed lower ethanol fractions than represented by the 1.1 
value proposed by EPA for hot soak plus diurnal emissions, and 
uniformly showed very low ethanol fractions for refueling 
measurements.\376\
---------------------------------------------------------------------------

    \376\ Passavant, G. (2013, October). Manufacturer Data on 
Ethanol Measurements in the SHED. Memorandum to the docket.
---------------------------------------------------------------------------

    EPA has reviewed the data provided by the manufacturers and has 
considered their comment that they should be given the option to 
measure the ethanol fraction and adjust the SHED results rather than be 
required to use a fixed correction factor. Based on these 
considerations, EPA is establishing the following approach with regard 
to ethanol corrections. First, EPA will permit measurement or the use 
of a fixed correction factor on an evaporative family by evaporative 
family basis. However, once the manufacturer selects an approach for 
any given evaporative family, that approach must be used in all 
subsequent testing of all vehicles certified using that data including 
carry over. For example, if a manufacturer chooses to measure the 
ethanol fraction for purposes of certification of a test group in a 
given model year, that same method must be used in any manufacturer 
confirmatory testing as well as IUVP or IUCP testing of all vehicles in 
that test group. Alternatively, if a manufacturer uses the fixed 
correction factor in certification it must also use it for all 
evaporative emission tests covered by the requirement for a given test 
group and for all follow on testing. Second, the decision on 
measurement or correction factor must be uniform on a test group basis 
for all evaporative emission standards covered by the correction 
requirement. In this case this includes hot soak, diurnal, high 
altitude, running loss, and rig test measurements. Third, in terms of a 
fixed correction factor, EPA believes that the 1.08 value adopted by 
California is consistent with the data and is specifying that value for 
hot soak plus diurnal (low and high altitude), running loss, and rig 
test measurement corrections for any testing conducted with 10 percent 
ethanol. Based on the data provided by the manufacturers, EPA is not 
requiring a fixed correction value or measurement for refueling, spit 
back, or canister bleed measurements for testing conducted with 10 
percent ethanol. This aligns with the expectation that ethanol 
concentrations will be very low with FID-based measurements and that 
mass-based measurements will capture any ethanol adequately without a 
need for correction. Finally, EPA will use the method selected by the 
manufacturer in any confirmatory or surveillance testing. However, 
since corrections will always be zero or greater, no correction is 
needed to make a failure determination if the FID value exceeds the 
emission standard or FEL. With regard to the 1.08, EPA remains open to 
future revisions to this value, in coordination with CARB, if a fuller 
data set representative of various vehicle models, SHED FID ethanol 
response values, FID designs (analog vs. digital), ethanol calculation 
approaches (photo acoustic and impinger), and test sites demonstrates 
that a different value would be technically appropriate and adequately 
conservative relative to the direct measurement methods permitted in 40 
CFR 1065.
    For higher ethanol blends (such as E85), the regulation already 
specifies measurement and calculation procedures to adjust for this 
effect. We are not making any changes to these procedures.
d. Vehicle Preconditioning for Nonfuel Hydrocarbon Emissions for the 
Tier 3 Evaporative Emission Standards
    The Tier 3 hot soak plus diurnal, leak, and canister bleed emission 
standards taken together are expected to bring about the widespread use 
of technology which effectively eliminates fuel vapor emissions. The 
fuel rig, canister bleed, and leak standards are not influenced by 
nonfuel hydrocarbon emissions from the vehicle. Nonfuel hydrocarbon 
emissions from the vehicle are measured as part of SHED emission 
testing, and are indistinguishable from fuel hydrocarbons when a FID is 
used to measure the concentration. The level of these nonfuel 
hydrocarbon emissions vary by vehicle and component design and 
material. These emissions arise from paint, adhesives, plastics, fuel/
vapor lines, tires, and other rubber or polymer components and are 
generally greater with larger size vehicles. These nonfuel hydrocarbon 
emissions are usually highest with newly manufactured vehicles and 
decrease relatively quickly over time.
    Currently, manufacturers normally conduct some preconditioning to 
reduce or eliminate the effects of these nonfuel hydrocarbon emissions 
on evaporative emissions measurements in the SHED. In the past, this 
practice has not been addressed through regulatory provisions. However, 
given the stringent level of the Tier 3 hot soak plus diurnal 
evaporative emission standards, and that nonfuel hydrocarbon emissions 
are expected to be a significant portion of the hydrocarbon emissions 
measured in the SHED, EPA believes that some sort of preconditioning 
before certification testing is appropriate and that a regulatory 
provision addressing this practice is warranted. Providing some 
recognition of and allowance for this practice will help to create the 
proper balance between necessary and proper preconditioning to address 
high nonfuel hydrocarbon emissions and excessive preconditioning which 
could undermine the intent of the hot soak plus diurnal emission 
standard (~ 50 mg or less of fuel evaporative emissions). EPA believes 
the goal of evaporative emissions preconditioning should be to get 
nonfuel hydrocarbon emissions to what we call vehicle background 
levels. A working definition of vehicle background level might be the 
level which will occur naturally twelve months after production. A 
provision in the regulations which addresses preconditioning reduces 
ambiguity for the manufacturers and could reduce or eliminate any 
uncertainty in the true meaning of certification test results.
    Manufacturer activity with regard to preconditioning often involves 
two practices. First, manufacturers in some cases ``bake'' their test 
vehicles at temperatures of 50 [deg]C or higher for periods of up to 
ten or more days to accelerate the off-gassing of these nonfuel 
hydrocarbon emissions before testing is conducted. While this practice 
is common, there is no standardized method or protocol for this 
preconditioning prior to new vehicle certification testing. For 
example, some manufacturers bake for a set period of time in a climate 
chamber while others

[[Page 23513]]

bake in the climate chamber and periodically measure nonfuel background 
in a SHED until an acceptable or stable level of nonfuel hydrocarbon 
emissions is achieved. Second, manufacturers often remove, modify, or 
clean certain components which are the largest source of nonfuel 
hydrocarbon emissions. Preconditioning could also include measures to 
eliminate minor fuel drips, spills, or other fuel remnants which occur 
as a result of vehicle preparation for testing.
    We are not specifying standardized pre-conditioning practices or 
protocols with regard to addressing nonfuel hydrocarbon emissions 
before evaporative emission certification testing. However, we are 
finalizing general provisions in four areas. First, we specify in the 
regulations that preconditioning for the purpose of addressing nonfuel 
hydrocarbon emissions is permitted. Second, we specify that any 
preconditioning is voluntary. Third, we specify that if preconditioning 
is conducted, the details must be specified to EPA before certification 
testing, (i.e., at the time of the pre-certification planning meeting). 
The goal of this preconditioning should be to get nonfuel hydrocarbon 
emissions to vehicle background levels as discussed above. The 
specifics to be discussed with EPA could include details on vehicle 
baking practices such the temperature and time duration in the climate 
chamber and practices conducted as an alternative or complement to 
vehicle baking such as installing used tires (drive and spare) on 
certification vehicles, and allowing the windshield washer tank to be 
filled only with water. EPA's goal in these discussions is to gain 
certainty that manufacturers are not preconditioning vehicles so 
severely that they create a level of nonfuel hydrocarbons that is 
artificially low and would not occur in use and thereby creating a 
false additional compliance margin for fuel hydrocarbons in the 
certification test. Fourth, except as discussed below we are providing 
in the regulations that no pre-conditioning is permitted for testing of 
any vehicle aged more than twelve months from its date of manufacture. 
This restriction for vehicles older than 12 months includes 
certification, confirmatory and in-use testing for any vehicle 
certified to the Tier 3 evaporative emission standards. For these 
vehicles, nonfuel hydrocarbon emissions will presumably be reduced to a 
stable level due to natural off gassing which begins after the vehicle 
is manufactured. Emissions from any replacement parts or other vehicle 
maintenance will presumably be encompassed within the margin below the 
standard created by this natural off-gassing.
    EPA received several comments concerning the proposed restriction 
on pre-conditioning of vehicles older than 12 months from the date of 
manufacture. The Alliance of Automobile Manufacturers and the 
Association of Global Automakers asked that baking be permitted if such 
a vehicle is found to have identifiable contamination due to causes 
such as a fuel spill, refrigerant leak, or washer fluid leak and that 
the manufacturer be given the option to age the tires (tires only) from 
any vehicle where the tires are less than twelve months from 
manufacture as indicated on the sidewall. CARB asked that EPA only 
allow the use of an aged spare tire in any testing and not spare tire 
removal. EPA generally agrees with these commenters and is finalizing 
provisions for limited flexibility subject to EPA approval. Under these 
provisions manufacturers may be permitted to clean any spills or leaks 
but not to bake the entire vehicle. Baking of tires less than 12 months 
old may also be permitted with EPA prior approval. Vehicles must be 
tested with a spare tire in place since emissions from the spare tire 
were considered as the standard was developed. Manufacturers may 
exchange a new spare tire for one that is baked or aged. Finally, one 
manufacturer indicated that there may be circumstances where the base 
chassis for a certification vehicle was used in previous certification 
but that this base chassis was modified for a new model year and 
cleaned, reconfigured, and recertified with new components which affect 
background emissions.\377\ While EPA believes this would be a rare 
occurrence, regulatory provisions in this rule allow EPA to approve 
additional pre-conditioning for vehicles in this situation upon 
manufacturer request and justification.
---------------------------------------------------------------------------

    \377\ See public comment EPA-HQ-OAR-2011-0135-4299 and 
Passavant, G. (2013, October). VW Email to EPA Regarding Vehicle 
Preconditioning. Memorandum to the docket.
---------------------------------------------------------------------------

e. Reciprocity With CARB
    Over the past 15 years EPA's ``enhanced evap'' test procedures have 
been based on testing with 9 pound per square inch (psi) RVP gasoline 
with test temperatures representing a summer day with peak temperatures 
of about 96 [emsp14][deg]F. CARB adopted the same basic procedures, but 
specified that testing should occur with 7 psi RVP gasoline at 
temperatures of up to 105[emsp14][deg]F. EPA and CARB agreed that 
certification could be based on testing with either EPA or CARB 
conditions and that these provided equivalent stringency for purposes 
of evaporative control system design. However, the provision allowing 
for this equivalence of test data preserved EPA's ability to also test 
with either EPA or CARB temperature conditions and related test fuels. 
CARB always specified EPA test conditions for refueling as they were 
deemed worst case. CARB recently changed their certification test fuel 
to a 7 RVP gasoline with 10 percent ethanol and as discussed in Section 
IV.F, we are changing the Federal certification test fuel specification 
to a 9 RVP gasoline with 10 percent ethanol.
    During the development of this FRM we carefully considered the 
practice of CARB/EPA reciprocity with regard to certification test 
fuels, hot soak plus diurnal test procedures, running loss test 
procedures, and emission test results when it comes to evaporative 
emissions certification. Based on these considerations and the 
alignment of the ethanol content for the EPA and CARB certification 
fuels, we have decided to retain our current approach with regard to 
CARB/EPA reciprocity for evaporative and refueling emissions. EPA and 
CARB have agreed to continue accepting emission test data on each 
other's test fuels and temperature conditions for certification such 
that a uniform national program for certification test fuel will be 
able to exist. For model years during the evaporative emissions 
standard phase-in discussed above (ending after the 2021 MY), EPA will 
conduct any post certification testing on any vehicle in the Tier 3 
program manufactured in the 2015-2021 MYs using the fuel and 
temperatures used by the manufacturer for certification. This approach 
covers families certified using carry over PZEV evaporative emissions 
data (through the 2019 MY) and LEV III Option 1 certifications (through 
the 2021 MY). Our program flexibility in the area of test fuels for hot 
soak plus diurnal, running loss and SHED rig/canister bleed emission 
standards is summarized in Table IV-25. After the 2021 model year, EPA 
will retain the option to test on either set of temperatures/fuels. 
This applies to all evaporative emission standards (hot soak plus 
diurnal, running loss, and canister bleed). For the other emission 
standards (refueling, leak, spit back, and high altitude hot soak plus 
diurnal) EPA will use the test fuel used by the manufacturer through 
the 2019 model year. For the 2020 model year and later we may use Tier

[[Page 23514]]

3 fuel or California Phase 3 if its use is permitted for certification. 
Please refer to the regulatory text for specific provisions.
    EPA will review all Tier 3 program evaporative emissions data. If 
the data shows that the EPA and CARB based test requirements give fully 
equivalent results, in the future we may revise our regulations so that 
a vehicle is always tested on the fuel used for its initial 
certification.

                    Table IV-25--Tier 3 Evaporative Emissions Program Options and Test Fuels
----------------------------------------------------------------------------------------------------------------
                                                                          EPA test fuel for
                           Start                                            confirmatory,     End MY for use in
     Vehicle program         MY     Program standards      Cert fuel       surveillance &           Tier 3
                                                                                IUVP
----------------------------------------------------------------------------------------------------------------
PZEV zero evap..........     2015  Hot soak +          CA Ph. 2........  Fuel used by the    After 2019 MY.
                                    diurnal, running                      manufacturer.
                                    loss & SHED rig.
LEV III Opt. 1..........     2015  Hot soak +          CA Ph. 3........  CA Phase 3 through  After 2021 MY.
                                    diurnal, running                      2019 MY, after
                                    loss & SHED rig.                      EPA may use Tier
                                                                          3 or CA Phase 3.
LEV III Opt. 2..........     2015  Hot soak +          CA Ph. 3........  CA Phase 3 through  N/A.
                                    diurnal, running                      2019 MY, after
                                    loss & canister                       EPA may use Tier
                                    bleed.                                3 or CA Phase 3.
Tier 3..................     2015  Hot soak +          Tier 3..........  Tier 3............  N/A.
                                    diurnal, running
                                    loss & canister
                                    bleed.
----------------------------------------------------------------------------------------------------------------
As shown in Table IV-22, to qualify as a Tier 3 vehicle for evaporative emission purposes vehicles must meet the
 hot soak + diurnal, high altitude, rig/canister bleed, running loss, refueling, and spit back standards. The
 leak standard applies beginning in the 2018 MY and the SHED rig/canister bleed tests are program specific.
----------------------------------------------------------------------------------------------------------------

    Generally, a vehicle test group using Tier 3 certification fuel and 
test procedures for meeting the various evaporative and refueling 
emission standards will qualify for inclusion in the Tier 3 evaporative 
emission standards phase-in. However, EPA recognizes that the 
California and federal evaporative emission standard programs are 
starting from different bases and that the transition provisions are 
different in some ways. For example, the EPA program starts in the 2017 
MY but after that has the same basic program construct as CARB in 2018. 
However, prior to the 2017 MY, CARB has a ZEV program provision which 
will continue to bring zero evap technology into the fleet before the 
2017 MY and CARB also allows early LEV III Option 1 and Option 2 
evaporative emission certifications. To capitalize on this technology 
and to facilitate transition, we are finalizing provisions that any 
CARB evaporative emission test data from MYs 2015 and 2016 PZEV zero 
evap certifications (hot soak plus diurnal and running loss) can be 
used in federal certification for those evaporative families through 
the 2019 MY. Similarly, we are finalizing provisions that CARB LEV III 
Option 1 certifications (hot soak plus diurnal and running loss) can be 
used in federal certification for those evaporative families through 
the 2021 MY. Assuming the vehicle test groups also meet the Tier 3 high 
altitude evaporative emission standards, the refueling emission 
standard, the spit back standard, and the leak standard when 
applicable, they could be included in the percentage phase-in 
calculations as Tier 3 vehicles. If the vehicles do not meet the Tier 3 
evaporative emission requirements manufacturers could potentially sell 
them nationwide, but they could not be included as Tier 3 compliant 
vehicles in the percentage phase-in calculation. Table IV-22 provides a 
concise summary of the requirements a vehicle must meet to qualify as a 
Tier 3 vehicle during the program's early, transition, and phase-in 
periods.
    EPA proposed a similar provision for a manufacturer who elects to 
use the CARB test procedures and test fuels to meet the refueling 
emission standard. However, no manufacturer indicated interest in their 
comments and we have decided not to include reciprocity for this 
provision in the Tier 3 program. While experimental data based on field 
bench testing suggests that the CARB test fuel RVP and dispensed 
temperature together would give the same results as the EPA test fuel 
RVP and dispensed temperature there are no vehicle test data in the 
record at this time. CARB has always accepted refueling and spit back 
certification on EPA test fuel and will continue to do so in the 
future. This provision would have added another layer of complexity to 
the program and was not necessary since the refueling and evaporative 
tests are done separately.
f. Evaporative and Refueling Emission Standards for Various Fuels
    The evaporative and refueling emission standards apply in different 
ways to different fuels. First, with regard to the evaporative emission 
standards, Clean Air Act section 202(k) specifies that gasoline-fueled 
vehicles must be certified to evaporative emission standards. Section 
202(a) authorizes EPA to establish evaporative emission standards for 
other fuels. Today evaporative emission standards apply to LDVs, LDTs, 
MDPVs, and HDVs fueled by gasoline methanol, ethanol, natural gas, and 
liquified petroleum gas (LPG). For the refueling emission standard the 
situation is quite different. Section 202(a)(6) of the Clean Air Act 
specifies that the refueling emission standards apply to all LDVs 
regardless of the fuel used. Section 202(a) of the Clean Air Act 
authorizes EPA to establish emission standards for other fuels and 
classes of vehicles. Prior to the Tier 3 final rule, the refueling 
emission standards applied to all vehicles less than 10,000 lbs GVWR 
regardless of the fuel used.
    In the NPRM, EPA requested comment on applying the refueling 
standards to all vehicles regardless of fuel used. This would include 
all volatile fuels.\378\ The evaporative standards apply today to all 
volatile fuels \379\ (except for diesel) and we asked for comment on 
explicitly including dedicated ethanol as well as fuel-cell vehicles, 
and electric vehicles. EPA also requested comment on applying the 
refueling and evaporative standards only to vehicles using volatile 
liquid fuels instead of all volatile fuels.
---------------------------------------------------------------------------

    \378\ A volatile fuel is a volatile liquid fuel or any fuel that 
is a gas at atmospheric pressure; gasoline, methanol, ethanol, 
natural gas, and LPG are volatile fuels.
    \379\ A volatile liquid fuel is a fuel that is liquid at 
atmospheric pressure and has a Reid Vapor Pressure higher than 2.0 
pounds per square inch--gasoline, ethanol, and methanol.
---------------------------------------------------------------------------

    EPA received four comments on this issue. One commenter expressed 
the view that evaporative requirements should be expanded to apply to 
volatile liquid fuels plus liquified petroleum gas (LPG) and liquified 
natural gas (LNG) while the three other commenters did not see the need 
to apply the

[[Page 23515]]

requirements to any gaseous fueled vehicle or other vehicle using a 
non-volatile liquid fuel because these vehicle fuel systems are sealed 
and rarely vent during normal operation or never vent at all.
    As is discussed further in the Summary and Analysis of comments, 
based on the comments, the fuel properties, and current industry fuel 
system design practices, EPA has decided to retain the requirement that 
the evaporative and refueling emission standards apply to vehicles 
using any volatile fuel. For gaseous fueled vehicles (LPG and LNG/CNG 
vehicles), only the Tier 3 3-day hot soak plus diurnal and running loss 
standards apply. For the other volatile fuels all of the Tier 3 
evaporative emission standards apply. For the refueling emission 
standard the requirements apply to all complete vehicles less than 
10,000 lbs GVWR regardless of the fuel used. This is not being changed, 
except that the requirement will not apply to diesel-powered LDTs and 
HDVs vehicles. For vehicles over 10,000 lbs GVWR, the refueling 
emission standards will apply only to complete vehicles. This includes 
LPG, CNG, LNG, and dedicated ethanol or methanol vehicles. While the 
test procedures for these standards would apply, EPA is including 
regulatory provisions to permit manufacturers to certify based on 
related data, engineering analysis, and compliance with published 
consensus standards. We are not applying these requirements to electric 
or fuel cell vehicles.
    For vehicles equal to or less than 8,500 lbs GVWR, the Tier 3 
evaporative and refueling emission standards for alternative fuel 
vehicles apply to each vehicle of a vehicle evaporative/refueling 
family as the family is included in the manufacturer's phase-in for the 
Tier 3 evaporative emission standards. For vehicles over 8,500 lbs 
GVWR, the application of the Tier 3 evaporative emission standards 
depends on the Job 1 (first build) date for the vehicle evaporative 
family. If the Job 1 date for a vehicle model is before the fourth 
anniversary date of the signature of the rule then the Tier 3 
evaporative emission standards do not apply until the next model year. 
If the Job 1 date is after the fourth anniversary date, the Tier 3 
evaporative emission standards apply in that model year. This 
determines when the vehicle is to be included in the denominator of the 
percentage phase-in calculation. The refueling emission standard 
applies only to complete vehicles and we are applying the same phase-in 
requirements as for complete HDGVs. For complete vehicles between 
10,000 and 14,000 lbs GVWR the refueling emission standard applies in 
the 2018 model year. For complete vehicles with a GVWR in excess of 
14,000 lbs GVWR, compliance is required in the 2022 model year. 
Finally, for all small businesses, the Tier 3 evaporative and refueling 
emission standards do not apply until the 2022 model year.
g. Other Changes and Future Considerations
    This rulemaking included consideration of several amendments or 
clarifications to existing requirements related to evaporative 
emissions. As part of this process, EPA has concluded that the 
following provisions warrant adjustment, clarification, or correction:
     Even though the evaporative emission standards in 40 CFR 
part 86 apply to the same engines and vehicles that must meet exhaust 
emission standards, we require a separate certificate for complying 
with evaporative and refueling emission standards. An important related 
point to note is that the evaporative and refueling emission standards 
always apply to the vehicle, while the exhaust emission standards may 
apply to either the engine or the vehicle. Since we plan to apply 
evaporative/refueling/leak standard and the recently adopted greenhouse 
gas standards to vehicle manufacturers, we believe it will be 
advantageous to have the regulations related to their certification 
requirements written together as much as possible to reduce burden and 
increase efficiency. Therefore, for 2015 and later model years, we are 
moving the emission standards and certification requirements for HDGVs 
from 40 CFR part 86 to the new 40 CFR part 1037, which was originally 
used for greenhouse gas standards for heavy-duty highway vehicles. This 
is not intended to change the requirements that apply to these 
vehicles, except as noted in this section.
     Section 86.1810-01 contains specifications addressing 
whether diesel fuel vehicles can be waived from demonstrating 
compliance with the refueling emission standard through testing. In the 
existing regulation the potential for a waiver from testing depended on 
the diesel fuel having an RVP equal to or less than 1 psi and the fuel 
tank having a temperature which does not exceed 130[emsp14][deg]F. We 
have examined this provision and are withdrawing the fuel temperature 
limit specification. Short of fuel spillage in the SHED, EPA sees no 
likelihood that a diesel fueled vehicle with RVP less than 1 psi could 
fail the refueling emission standard even at fuel tank temperatures 
above 130[emsp14][deg]F. This is due to the inherently low vapor 
pressure of diesel at these temperatures and the likelihood that vapor 
shrinkage conditions will occur in the fuel tank during refueling since 
the dispensed fuel will be much cooler than the tank fuel.
     When adopting the most recent prior set of evaporative 
emission regulatory changes we did not carry through the changes 
applying evaporative emission standards to vehicles using methanol-
fueled compression-ignition engines. This final rule corrects this 
oversight.
     We are finalizing provisions to address which standards 
apply when an auxiliary (nonroad) engine is installed in a motor 
vehicle, which is currently not directly addressed in the highway 
regulation. The approach requires testing complete vehicles with any 
auxiliary engines (and the corresponding fuel-system components). 
Incomplete vehicles are to be tested without the auxiliary engines, but 
any such engines and the corresponding fuel-system components will need 
to meet the standards that apply under our nonroad program as specified 
in 40 CFR part 1060.
     We are removing the option for secondary vehicle 
manufacturers to use a larger fuel tank capacity than is specified by 
the certifying manufacturer without re-certifying the vehicle. 
Secondary vehicle manufacturers needing a greater fuel tank capacity 
must either work with the certifying manufacturer to include the larger 
tank, or go through the effort to re-certify the vehicle. This 
provision has not been used and is better handled as part of 
certification rather than managing a separate process. We are including 
corresponding changes to the emission control information label.
     We are revising the provisions for setting the vehicle air 
conditioning controls during the running loss portion of the 
evaporative emissions test cycle to simply reference the specifications 
for exhaust emission testing described in 40 CFR part 1066. This allows 
test labs to use a uniform set of test procedures for setting up test 
vehicles. This change is expected to have no effect on the stringency 
of the running loss test.
     EPA regulations at Sec.  86.1824-01 permit manufacturers 
to develop their full-useful life deterioration factors for evaporative 
and refueling emission standards based on the use of good engineering 
judgment. These factors are additive in nature, and when added to the 
``undeteriorated low mileage'' test value the sum must be less than the

[[Page 23516]]

applicable emission standard or FEL. Manufacturers usually certify such 
that this summed value falls below the emission standard or FEL enough 
to provide a margin for in-use compliance and to address variability 
and other uncertainty. Regulations (at Sec.  86.1824-08) require that 
evaporative emissions durability assessments must employ gasoline fuel 
for the entire mileage accumulation period which contains ethanol in, 
at least, the highest concentration permissible in gasoline under 
federal law and that is commercially available in any state in the 
United States (currently E15). In their comments the Alliance of 
Automobile Manufacturers and the Association of Global Automakers asked 
to be able to use evaporative emissions deterioration factors from Tier 
2/LEV II assessments even if the assessed or measured full life 
emission value used to determine the deterioration factor from the Tier 
2/LEV II 2 testing is above the Tier 3/LEV III emission standard for 
the vehicle category of interest. (This situation, which is often 
referred to as line crossing, is not prohibited in the EPA regulation.) 
\380\ Thus, EPA is permitting the use of this data but requires that: 
(1) The manufacturers use good engineering judgment in the testing used 
to develop their deterioration factors and the assessment and 
application of this data in developing deterioration factors, (2) the 
manufacturers use the evaporative/refueling emissions test fuel as 
stipulated in the regulations for Tier 3, and (3) the addition of the 
deterioration factor to the low mileage test result does not result in 
an exceedance of the emission standard or the FEL cap for that category 
of vehicles.
---------------------------------------------------------------------------

    \380\ Passavant, G. (December 2013) Background Information on 
Background Information: Carryover of Emissions Data and Line 
Crossing. Memorandum to the docket.
---------------------------------------------------------------------------

D. Improvements to In-Use Performance of Fuel Vapor Control Systems

1. Reasons for Adding a Leak Test Standard
    As emission standards approach zero, as in the ``zero evap'' 
standards discussed above, in-use performance becomes critical for 
vehicles to meet the standards over their useful life periods and 
provide the expected emission reductions. Fuel vapor control system 
leaks are not a new problem, in fact it was one of the main reasons for 
replacing the canister method for assessing evaporative emissions with 
the enclosure (SHED test) method used today.\381\ However, as emission 
standards have become more stringent, test procedures have improved, 
and vehicle lifetimes have increased, any malfunction or deterioration 
in the system causes significant emissions increases. Even a small leak 
can cause large amounts of HC vapor. Therefore, the prevalence of leaks 
in the fleet can have a significant effect on the average evaporative 
emissions overall.
---------------------------------------------------------------------------

    \381\ Rarick.T, ``Evaporative Emission Enclosure (SHED) 
Procedure Analysis of Surveillance Program Data,'' Evap 75-2, June 
1975 and ``Investigation and Assessment of Light-Duty Vehicle 
Evaporative Emission Sources and Control,'' EPA-460/3-76-014, June, 
1976.
---------------------------------------------------------------------------

    As discussed in detail in the NPRM, recent laboratory and field 
data \382\ show very high emissions from vehicles with liquid/vapor 
leaks. Field studies have indicated approximately 10 percent of overall 
fleet have significantly elevated evaporative emissions. The studies 
show that this frequency increases as vehicles age. The Coordinating 
Research Council (CRC) E-77 programs randomly recruited sixteen 
vehicles and almost half had some type of leak. Emissions related to 
these leaks grew in magnitude over the course of the program which 
lasted a few years. In addition, the EPA recently completed a test 
program to gather information on running loss emissions with implanted 
leaks of varying sizes, locations and fuel volatility.\383\ Data from 
this study is not included in the modeling analysis for this final 
rule, but the results show that there are significant emissions from 
leaks while driving as the fuel tank temperature rises. Therefore the 
reductions from the future prevention of leaks will be larger than our 
current estimates. These data led EPA to examine the OBD-based 
evaporative system leak data available from I/M programs from several 
states to more accurately gauge the rate of leaks above the 0.020 inch 
monitoring threshold met by most manufacturers as a result of CARB's 
2004 model year OBD II requirements.\384\ These are important data 
because even a vehicle with a fuel/evaporative system leak as small as 
0.020 inches would be expected to fail the Tier 3 evaporative emission 
standard in a SHED test and in fact emit 4-5 times above the Tier 3 
emission standard on a daily basis due to the number of vehicle trips 
per day.
---------------------------------------------------------------------------

    \382\ CRC E-77 reports: Haskew, H., Liberty, T. (2008). Vehicle 
Evaporative Emission Mechanisms: A Pilot study, CRC Project E-77; 
Haskew, H., Liberty, T. (2010), Enhanced Evaporative Emission 
Vehicles (CRC E-77-2); Haskew, H., Liberty, T. (2010), Evaporative 
Emissions from In-Use Vehicles: Test Fleet Expansion (CRC E-77-2b); 
Haskew, H., Liberty, T. (2010), Study to Determine Evaporative 
Emission Breakdown, Including Permeation Effects and Diurnal 
Emissions Using E20 Fuels on Aging Enhanced Evaporative Emissions 
Certified Vehicles, CRC E-77-2c; DeFries, T., Lindner, J., Kishan, 
S., Palacios, C. (2011), Investigation of Techniques for High 
Evaporative Emissions Vehicle Detection: Denver Summer 2008 Pilot 
Study at Lipan Street Station; DeFries, T., Palacios, C., Weatherby, 
M., Stanard, A., Kishan, S. (2013) Estimated Summer Hot-Soak 
Distributions for Denver's Ken Caryl I/M Station Fleet.
    \383\ Kishan, S., Sabisch, M., Stewart, J., Glinsky, G. (2014) 
Running Loss Testing with Implanted Leaks.
    \384\ Weatherby, M., Sabisch, M., Kishan, S. (2014) Analysis of 
Evaporative On-Board Diagnostic (OBD) Readiness and DTCs Using I/M 
Data. Note: the data was presented in a docket memo for NPRM\ and is 
now part of a peer reviewed report.
---------------------------------------------------------------------------

    We examined data for vehicles meeting CARB's OBDII evaporative 
emission leak monitoring requirements as well as either the CARB/EPA 
enhanced evaporative emission or Tier2/LEV II evaporative emission 
standards. Since the data were gathered by the states under different 
protocols and time periods, the content of the data sets is not 
identical. To provide some degree of uniformity in our analysis, we 
examined the data for model years 2000 and later, but within each state 
we only looked at calendar years of data beginning after the initial 
state I/M exemption period had passed (2-6 calendar years depending on 
the state). Thus the analysis focused on I/M OBD information for 
calendar years 2004-2012.
    Examined together, the data generally indicate the following.
     For all our States analyzed, the trend lines show that 
between 2-4 percent of the vehicles entering the I/M program (at about 
2 years old) have a ``not ready'' evaporative monitor. The percentage 
increased to between 8-11 percent as the vehicle aged to 8 years old 
with a rate increase of approximately 1 percent per year as the vehicle 
ages.
     The model years and time periods analyzed for the four 
States shows approximately 0.7-2.5 percent of vehicles overall with a 
``ready'' evap monitor had one or more stored evap DTCs, indicating a 
potential evaporative emissions-related problem as defined in the OBD 
regulations.
     A further review of the data shows that, overall, in the 
three States with an enforced OBD program approximately 0.7-1.6 percent 
of vehicles with a ``ready'' evap monitor had one or more stored 
evaporative emissions related DTCs. The fourth State, which does not 
enforce the OBD test, had a higher percentage (2.5 percent) of evap 
monitor ``ready'' vehicles that had stored evap related DTCs.
     For the same model years and time periods analyzed for the 
three States with enforced OBD programs, EPA

[[Page 23517]]

estimates about 0.5 percent of vehicles with a ``ready'' evap monitor 
evaluated at four years old in an I/M program had a stored DTC. This 
rate increased at a rate of about 0.15 percent per year and was about 
1.1 percent for vehicles at 8 years old. For the fourth state, which 
does not enforce OBD evaporative results, EPA estimates about 1.4 
percent of vehicles evaluated at four years old had a stored DTC. This 
rate increased at a rate of about 0.5 percent per year and was about 
3.5 percent for vehicles at 8 years old.
     Analyzing each state's data for specific evaporative DTCs, 
over 50 percent of all evaporative codes were for evaporative system 
leaks. The second most common category (15-20 percent) involved some 
sort of error in the operation of the purge flow control which could 
also contribute to evaporative leaks.
     The monitor ``ready'' rates are relatively uniform for all 
States analyzed, but the percentage of evaporative emissions related 
MILs illuminated and the percentage of evaporative system leak related 
DTCs were larger in the fourth State. EPA believes this is the case 
because OBD is advisory only in this State's I/M program, meaning that 
a vehicle could pass its I/M requirement with a MIL illuminated and not 
have to repair it.
    In considering this information for the fleet as a whole, a few 
other factors must be considered. First, a vehicle can pass its I/M 
requirements (based on provisions of individual State I/M programs) 
with the evaporative emissions monitor ``not ready''. Second, the 
vehicle can pass with a pending DTC. Third, it is not uncommon for 
vehicle repair related to an OBD MIL to occur just before I/M visits. 
Based on factors such as these, the values presented above are likely 
to be conservative on a fleet average basis. Beyond this, as discussed 
in the NPRM, earlier research conducted by EPA and the state of 
Colorado indicated that OBD is not designed to catch every evaporative 
system leak and sometimes misses leaks it should have found but did not 
for various reasons (some determined and some unknown).\385\ This 
suggests that overall leak prevalence is higher than indicated by the 
OBD data alone.
---------------------------------------------------------------------------

    \385\ Eastern Research Group (2013) Evaluation of the 
Effectiveness of On-Board Diagnostic (OBD) Systems in Identifying 
Fuel Vapor Losses from Light-Duty Vehicles.
---------------------------------------------------------------------------

    Estimating a nationwide fleet average leak rate is possible with 
the limited data available if some informed assumptions are made. Only 
about 24.5 percent of vehicles in the U.S. are in I/M areas and of 
these only 20.8 percentage points (~4/5) are in areas which rely on OBD 
as part of the pass/fail protocol. There is at present no data on the 
prevalence of evaporative system leaks for vehicles in areas without I/
M. However, based on these data it reasonable to assume that the rates 
in these areas are no less than for areas with I/M (where I/M mandates 
repair) and are likely similar to or larger than those for the one 
state analyzed where OBD is advisory only. Under those assumptions, the 
average leak rate across the country is much higher than for I/M areas 
alone. For example, if one considers data from the eight year age point 
in the I/M data for states which require repair, the leak prevalence 
rate is about 1.4 percent and in the state where OBD is advisory it is 
3.5 percent. Weighted by the fleet percentages given above, this 
indicates a leak rate of about 3.0 percent in the fleet for the eight 
year age point. This is a conservative estimate based on historic 
evaporative I/M data.\386\
---------------------------------------------------------------------------

    \386\ USEPA (2014), ``Development of Evaporative Emissions 
Calculations for Tier 3 FRM'' memorandum to the Tier 3 docket.
---------------------------------------------------------------------------

    The propensity for leaks in the vehicle fleet has the potential to 
reduce the benefits of the Tier 3 evaporative emission standards 
substantially. If on any given day, as few as 3 percent of Tier 3 
vehicles have a leak(s) of 0.020 inches or greater this will cause in-
use emissions equivalent to essentially all of the projected emission 
reductions from the Tier 3 evaporative emission standards on that 
day.\387\
---------------------------------------------------------------------------

    \387\ See EPA memorandum: ``Initial Comparison of Emission Rates 
from Vehicles with Fuel/Vapor System Leaks to Tier 3 Evaporative 
Emission Reductions, December, 2013.''
---------------------------------------------------------------------------

    The leak standard we are adopting will help technology to meet the 
Tier 3 evaporative emission standards and to improve in use durability. 
These technology measures (see Section IV.C.3) coupled with the upgrade 
to the OBD evaporative emissions certification and monitoring 
requirements to signal problems at smaller threshold diameters 
(discussed in Section IV.E below) and additions to the IUVP program 
focused on testing a larger sample of vehicles for fuel/evaporative 
system leaks in IUVP than for evaporative emission standards alone will 
help to ensure improved in-use performance of evaporative emission 
control systems.
    Based on the above discussion, there needs to be an increased focus 
on evaporative emissions durability. Nevertheless, there is no question 
of the value of OBD leak monitoring for evaporative systems, especially 
when owners complete needed repairs in response to the DTCs set. The I/
M OBD statistics and associated in-use leak values discussed above 
would be higher without OBD evaporative system leak monitoring. 
However, these data suggest that EPA OBD regulations in place for 2004 
and later model year vehicles will not alone be sufficient to address 
concerns regarding the emission effects of vapor leaks from the fuel 
and evaporative control systems.\388\
---------------------------------------------------------------------------

    \388\ Existing OBD regulations specify that if the fuel tank 
volume exceeds 25 gallons then the manufacturer may seek a larger 
leak detection orifice value. If a manufacturer seeks and is granted 
a larger value for OBD leak detection purposes, then that same 
numerical value becomes the leak standard value. We do not expect 
this value to exceed 0.040 inches.
---------------------------------------------------------------------------

    In the NPRM, EPA included a substantial discussion of the work we 
conducted on high evaporative emission rates and our rationale for the 
need for a leak standard to help address these concerns. No commenter 
challenged the data or the premises for our conclusion that a leak 
standard was needed. Manufacturers asked that the leak standard be 
phased-in with the Tier 3 evaporative emission standards and that use 
of upgraded OBDII evaporative system monitoring capability be included 
as part of the in-use verification program (IUVP) provisions. Both 
elements are contained in this final rule. CARB fully supported the 
proposed leak standard and test procedure and indicated its intent to 
adopt such provisions after the Tier 3 FRM is adopted.
2. Nature, Scope and Timing of Leak Standard
    The evaporative emission standards in this FRM will help to promote 
widespread use of improved technology and materials which will reduce 
evaporative emissions in-use. The new requirement for a leak standard 
and test procedure will help to ensure the durability of Tier 3 
evaporative emission control systems nationwide. As discussed in the 
technological feasibility discussion in Section IV.C above, the actions 
of manufacturers to meet the Tier 3 evaporative emission standards are 
expected to address fuel/evaporative system design features which 
currently have a greater propensity for developing leaks and thus 
improve in-use durability for evaporative control systems compared to 
vehicles meeting previous evaporative emission standards. The leak 
standard will provide added assurance that as the manufacturers design 
for ``zero evap'' standards they

[[Page 23518]]

also design the systems to avoid leaks over the full useful life.
    Based on the information described above concerning evaporative 
emissions in-use, we believe a leak standard is necessary to ensure 
that vehicles meeting Tier 3 evaporative emission requirements not have 
evaporative emissions in excess of the Tier 3 standards for their full 
useful life. Toward that end, we are finalizing a leak standard to be 
met both at new vehicle certification and in use for IUVP testing. The 
leak standard will apply beginning in the 2017 MY to vehicles in the 
20/20 option for that year and in the 2018 MY and later model years to 
any vehicle certified to the Tier 3 evaporative emission standards or a 
CARB carryover vehicle counted toward the sales percentage phase-in 
requirements discussed in Section IV.C, including LDVs, LDTs, MDPVs, 
and complete HDGVs up to 14,000 lbs GVWR. The standard will be 
applicable for the same useful life period as for the evaporative 
emission standards that apply to the vehicle. The standard will apply 
to vehicles using volatile fuel (e.g., gasoline, FFV, and methanol fuel 
vehicles, but not diesel or CNG vehicles).
    To be compatible with CARB OBD requirements being met by most 
manufacturers and the OBD requirements included in this rule, we are 
specifying that the leak standard be expressed in the form of a 
cumulative equivalent orifice diameter. We are finalizing a value of 
0.02 inches.\389\ The standard basically requires that the cumulative 
equivalent diameter of any orifices or ``leaks'' in the system not 
exceed 0.02 inches. This is consistent with California OBD requirements 
(and those being finalized in this rule as well) that the OBD system be 
capable of identifying leaks in the fuel/evaporative system of a 
cumulative equivalent diameter of 0.020 inches. EPA believes a standard 
at this level is feasible since earlier testing programs identified 
vehicles with essentially no leaks and it is essentially equivalent to 
that required for CARB OBD evaporative system leak monitoring. We are 
finalizing a leak standard of 0.02 inches which with rounding is a bit 
less stringent than the 0.020 inch OBD evaporative system leak 
monitoring requirement. EPA believes this level of precision is 
sufficient to accomplish the air quality objective and yet provides 
some compliance margin between the standard and the monitor requirement 
such as is reflected through multipliers for the exhaust emission 
standards established for other OBD monitors. The leak standard will be 
specified to one significant digit (e.g., 0.02 inches) but will have to 
be measured and reported to at least two significant digits.
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    \389\ Existing OBD regulations specify that if the fuel tank 
volume exceeds 25 gallons then the manufacturer may seek a larger 
leak detection orifice value. If a manufacturer seeks and is granted 
a larger value for OBD leak detection purposes, then that same 
numerical value becomes the leak standard value. We do not expect 
this value to exceed 0.040 inches.
---------------------------------------------------------------------------

    The leak standard will apply at the time of certification as well 
as during confirmatory and in-use verification program testing. We do 
not expect that new vehicles being certified will have a leak problem, 
and since a vehicle with a leak would likely fail the evaporative 
emissions SHED test, there is little value in mandating a leak test at 
certification. Thus, EPA will permit a manufacturer to attest to 
compliance with the leak standard at certification.
    To implement the leak standard within the existing regulatory 
structure a few minor rule changes are being made. First, existing EPA 
regulations such as those at Sec.  86.098-24, specify criteria for 
evaporative/refueling emission families. EPA believes this basic 
structure is appropriate for the leak standard, with the additional 
criteria that vehicles in the same evaporative/refueling family must 
use the same basic approach to OBD leak detection. Significantly 
different volume fuel tanks would likely also be a family determinant, 
but we believe this is already covered by the evaporative/refueling 
family criteria. Second, since the leak standard is a pass/fail 
requirement and not an emission rate, there is no requirement for the 
application of a deterioration factor. Third, EPA requires that the 
manufacturers recommend two or more leak test points for each test 
group. One of these points should be near the canister/purge valve 
(ideally in the vapor line between the canister/purge valve and the 
fuel tank) and the other in the gas cap/fill pipe area. Three points 
are required for vehicles with two separate evaporative and refueling 
canisters such as non-integrated ORVR systems which employ two 
activated carbon canisters and four points are required for vehicles 
with dual fuel tanks and two separate evaporative/refueling control 
systems.
    EPA believes that linking the timing of the leak standard to the 
beginning of the phase-in of the Tier 3 evaporative emission standards 
in the 2018 model year provides adequate lead time and is consistent 
with the technical rationale supporting the feasibility of the Tier 3 
evaporative emission standard.
3. Leak Standard Test Procedure
    The fundamental concepts underlying fuel/evaporative system leak 
test are not new to the manufacturers. There is already a simple leak 
check in 40 CFR 86.608-98(a)(1)(xii)(A) and in the past at least three 
states included a fuel/evaporative system pressure leak test in I/M 
programs. More importantly, all LDVs, LDTs, MDPVs and HDGVs 
manufactured today have the onboard capability to run a pressure or 
vacuum leak based check on the vehicle's evaporative emission system as 
part of OBD evaporative system leak monitoring. These systems employ 
either positive or negative pressure leak detection pumps or operate 
based on natural vacuum for negative pressure leak detection. EPA is 
finalizing a test based on a similar concept of placing the system 
under a slight positive pressure (but from an external source), 
measuring the flow needed to maintain that pressure in the fuel/
evaporative control system, and converting that flow rate to an 
equivalent orifice diameter. With regard to the test procedure we will 
first discuss where the leak test can occur in the FTP test sequence. 
We will then discuss how the test is to be conducted. EPA proposed this 
test procedure as part of the NPRM and discussed it extensively in the 
preamble to the proposed rule, and provided a full draft of the 
Recommended Practice for comment as an Appendix to the RIA. No comments 
were received. We are finalizing this test procedure as proposed.\390\
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    \390\ Smith, P. and Passavant, G., ``Recommended Test Procedure 
and Supporting Testing Data for the Evaporative Emissions Leak 
Test'', December 2013.
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    First, when conducted, the leak test should be completed 
immediately following the first two preconditioning steps within the 
FTP sequence (see Figure B96-10 in 40 CFR 86.130-96). Thus, the vehicle 
preconditioning steps for the leak test are: (1) Fill the vehicle fuel 
tank to 40 percent of capacity using the appropriate certification test 
fuel and then (2) let the vehicle soak for a minimum of a six hour 
period at a temperature in the range of 68-86 [deg]F. EPA requires that 
the test be conducted with 9 RVP E10 test fuel for both certification 
and IUVP.\391\ After preconditioning is complete, the leak test is 
conducted and the test sequence proceeds as prescribed in subpart B or 
testing is terminated if the purpose is only to conduct leak testing. 
EPA

[[Page 23519]]

believes this modest level of preconditioning is sufficient to create 
standard conditions which enable repeatable and reliable measurement 
results. Preconditioning cannot include any prescreening for leaks nor 
will any tightening of fittings or connections be permitted.
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    \391\ This is the same preconditioning that is called for in 
existing 40 CFR 86 subpart B for exhaust, evaporative, and refueling 
emissions testing. EPA will consider permitting the leak standard to 
be evaluated using CARB LEV III test fuel if CARB ultimately adopts 
this requirement.
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    After preconditioning is complete, manufacturers then run the leak 
test. To fully complete testing on a vehicle, two or more test points 
are required depending on the fuel evaporative system configuration. 
All points must pass for the vehicle test to be a pass. As discussed 
above, one of these points should be near the canister/purge valve 
(ideally in the vapor line between the canister/purge valve and the 
fuel tank) and the other in the gas cap/fill pipe area. Three points 
are required for vehicles with two separate evaporative and refueling 
canisters such as non-integrated ORVR systems which employ two 
activated carbon canisters and four points are required for vehicles 
with dual fuel tanks and two separate evaporative/refueling control 
systems such as dual tank LDTs. If the fuel/evaporative system has an 
embedded evaporative system test port then that point can be used. 
Also, a manufacturer can develop a test rig such as a ``fill pipe 
extension'' which screws into the fill pipe opening using cap threads 
at one end and on the other end has threads to screw the fill pipe 
vehicle cap in place. Within this extension there must be an access 
port for the leak test equipment to be attached. Thus, the full system 
could be tested without any direct intrusion or the need for a separate 
gas cap assessment. The manufacturer must specify the test points at 
the time of the pre-certification meeting. If the manufacturer selects 
an entry point which requires the fuel cap to be removed, then the cap 
will have to undergo a separate test as is now done in many I/M 
stations.\392\ In this case, tests from both points combined must pass 
the standard. Manufacturers commented that only one test point was 
needed, but when asked by EPA they offered no data to counter that 
provided by EPA in the NPRM which showed the potential for different 
results at different test point locations for the same vehicle.
---------------------------------------------------------------------------

    \392\ For related information see ``IM240 & Evap Technical 
Guidance'', EPA 420-R-00-007, April, 2000.
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    The procedure is conducted as follows:
     Calibrate the testing apparatus and otherwise verify 
testing apparatus is ready and able to complete the procedure.
     Seal fuel system so as to pressure test entire system 
(purge valve, cap, etc.).
     Attach test apparatus to vehicle's fuel system at selected 
test point.
     Pressurize fuel system with nitrogen or another inert gas 
to at least 2.4 kilopascals (kPa).
     Allow flow and pressure to stabilize in accordance with 
specification provided in the regulatory text.
     Calculate effective leak orifice diameter from measured 
output flow rate and temperature and pressure data or use apparatus 
with built in computer providing an equivalent digital readout. 
Calculate to the nearest 0.01 inch.
     Calculated effective orifice diameter must be less than or 
equal to the standard.
     If leak test is conducted at the fuel cap opening then the 
manufacturer must also show evidence that the vehicle's fuel cap is 
performing properly.\393\
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    \393\ Such tests are done routinely in I/M stations using a 
commercially available apparatus. The gas cap leak rate may be 
determined by pressure loss measurement, direct flow measurement, or 
flow comparison methods and shall be compared to a pass/fail flow 
rate standard of 60 cubic centimeters per minute of air at 30 inches 
of water column. The flow rate methods are referenced to standard 
conditions of 70 [deg]F and 1 atm.
---------------------------------------------------------------------------

     Use two or more separate test points, near the evaporative 
canister/purge valve and the other near the fuel cap are required. This 
is especially important if the fuel cap/fill neck area is isolated from 
the rest of the fuel/evaporative system as a result of the 40 percent 
fill or if dual tanks are not otherwise connected through vapor lines.
     Tests can be void if the test apparatus fails, becomes 
disconnected, fails to maintain a stable flow rate or pressure, or the 
test was stopped before completion due to safety considerations or some 
other relevant vehicle issue.
     Leak tests at all points (2 or more depending on the fuel 
tank/evaporative system configuration) must pass for a vehicle to pass. 
This includes performance within specification for the fuel cap if it 
is removed for testing.
    The test procedure presented above is based on current fuel system 
designs. In the future, it is reasonable to expect changes in designs 
of the fuel systems such that the procedure above may need adjustment. 
EPA will monitor these fuel system changes and modify the test 
procedure provisions as needed. Furthermore, existing EPA regulations 
(see Sec.  1065.10(c)) contain provisions which provide the opportunity 
for manufacturers to seek approval for special or alternate test 
procedures if from a practical perspective their systems cannot be 
evaluated under EPA requirements or they have an approach deemed 
equivalent or better. Any such special or alternative procedures must 
be reported under Sec.  86.004-21(b)(9).
4. Certification and Compliance
    As part of the Compliance Assistance Program (CAP 2000) in-use 
verification program (IUVP) \394\ the manufacturers began testing the 
evaporative emissions performance of small samples of in-use vehicles 
owned and used by the public. These regulations can be found at 40 CFR 
86 1845-01, and 1845-04. In 2000, EPA extended this requirement to 
cover chassis-certified HDVs, which for these purposes are basically 
all HDGVs up to 14,000 lbs GVWR.\395\ The in-use testing for 
evaporative emissions started in 2004 for 2001 MY LDVs, LDTs, and MDPVs 
and in 2008 for 2007 MY chassis certified HDGVs. Current IUVP data for 
evaporative emissions (including LDVs, LDTs, MDPVs, and HDGVs up to 
14,000 lbs GVWR) covers about 1800 vehicle tests. These data show that 
when evaluated in the laboratory using certification test procedures, 
the vast majority (over 95 percent) of the vehicles pass the 
evaporative emission standards to which they were certified. While this 
information is indicative of good in-use performance, it has 
limitations. First, the test results are for small sample sizes. For 
the approximately 150 million LDVs, LDTs, MDPVs, and chassis-certified 
HDGVs produced between 2001 (the start of the IUVP program) and 2010 
(latest available data), only about 0.001 percent of vehicles were 
tested. Second, the IUVP regulations place limits on the age/mileage 
for vehicle testing. Each model year is tested in two ``batches,'' 
nominally at the one and four year age points. One year old vehicles 
must have at least 10,000 miles and four year old vehicles must have at 
least 50,000 miles with at least one within the higher mileage group 
having an odometer reading of at least 75 percent of useful life 
(90,000 miles for most Tier 2 vehicles). With the even longer useful 
life periods under Tier 3, attention to in-use durability for 
evaporative systems becomes even more important. Including the leak 
standard within the IUVP protocol, as structured in the discussion 
below, will provide better information to EPA and manufacturers 
concerning evaporative system performance and help to focus 
manufacturer efforts on using designs

[[Page 23520]]

and hardware with full useful life durability in mind.
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    \394\ See 64 FR 23906 (May 4, 1999).
    \395\ See 65 FR 59922-59924 (October 6, 2000).
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a. In-Use Verification Program (IUVP) Requirements for the Leak 
Standard
i. Introduction
    We believe it is important to identify leaks since vehicles with 
leaks are expected to have daily emission rates above the Tier 3 
evaporative emissions standards, and the recent laboratory and field 
data \382\ suggest a propensity for the diameter of vehicle leak 
orifice to get larger over time and thus to have even higher emissions. 
This is also important because evaporative leak emissions occur 
virtually every day whether the vehicle is driven or not. Thus 
identifying potential leak problems is important to capturing the 
emission benefits of the Tier 3 evaporative emission requirements.
    Toward that end, EPA is including assessment of compliance with the 
leak standard within the IUVP program. In developing the proposed rule, 
we considered expanding the evaporative emission testing portion of the 
IUVP program as a means to assess leaks, but we decided to focus on the 
leak standard because it is less burdensome than a full evaporative 
emissions SHED test and is a cost effective step toward assessing many 
aspects of evaporative emissions performance in-use.
    EPA believes adding a leak test requirement does not create an 
unreasonable burden. The test procedure described above is simple to 
run, inexpensive to conduct in terms of equipment and labor, and can be 
completed relatively quickly compared to an evaporative emissions test. 
However, we are retaining the evaporative emissions testing 
requirements currently in IUVP to monitor broader evaporative control 
system effectiveness (e.g., purge, canister control efficiency, 
permeation).
ii. IUVP Test Requirements
    We are requiring that the leak test be conducted for each and every 
vehicle assessed in IUVP for exhaust emissions under 40 CFR 86.1845-04. 
This will begin for 2017 MY vehicles meeting the leak standard under 
the 20/20 option and more fully in the 2018 MY certifications for all 
test groups meeting the new leak standard. The leak test IUVP 
requirement includes the low and high mileage tests for any exhaust 
vehicle evaluated for exhaust emissions plus a requirement that there 
be at least one representative of each evaporative/refueling/leak 
family evaluated at each mileage/year point. We are finalizing this 
approach to implementing IUVP for the leak standard in lieu of creating 
a new set of requirements which would require another set of vehicles 
to be procured for testing. We are not including the leak test with any 
evaporative emissions test in IUVP, since a leak will be evident in the 
results of the evaporative emissions test.
    The existing IUVP regulations at Sec.  86.1845-04, Table S04-07, 
call for test sample sizes on a sliding scale based on annual vehicle 
sales by test group. This can vary from zero for very small sales test 
groups to six vehicles for test groups with sales exceeding 250,000. 
There are more exhaust emission test groups than there are evaporative/
refueling test families and exhaust emission test groups may cover one 
or more of the same evaporative/refueling/leak families, so we expect 
to receive multiple leak test results for most evaporative/refueling/
leak families. This will expand the amount of IUVP data we receive in 
this important area and improve our ability to assess the overall leak 
performance for a given evaporative/refueling/leak family and the fleet 
as a whole.
    As discussed above, EPA believes that the fuel and evaporative 
control system leaks are heavily influenced by age as well as design 
and other factors. EPA asked comment on extending the age point for 
leak testing for IUVP beyond the four year point to better assess this 
effect. However, in the past, manufacturers have expressed concern 
about the implications of testing older vehicles and about finding 
vehicles still within their warranty and recall liability periods. EPA 
believes further consideration of longer year test points is merited 
for exhaust, evaporative, refueling and leak tests but because such a 
change could potentially affect all four tests we have decided to defer 
that action to a broader IUVP program review. Extending the time point 
for the leak test alone would create a different programmatic test 
burden in terms of more vehicle procurements than the program laid out 
above.
iii. Assessment of IUVP Leak Emission Standard Test Results
    The existing regulations contain provisions addressing follow-on 
testing requirements for exhaust emissions for vehicles which fail to 
meet various performance thresholds within IUVP (see 40 CFR 86.1846-
01). As mentioned above, we expect that it will be common to get more 
than one leak test result over the course of each model year's mileage 
testing point for each evaporative/refueling/leak family as a result of 
the requirement to assess leaks with each exhaust IUVP test. However, 
the leak standard is basically pass/fail at 0.02 inches and it is 
difficult to establish a threshold criteria for a pass/fail standard 
such as has been done for exhaust emissions where there is a multiplier 
applied to the level of the individual exhaust emission standard.
    Given the importance of the leak standard in assuring in-use 
evaporative emissions control, we are finalizing a set of criteria for 
assessing leak standard results from IUVP. These criteria can be 
summarized as follows for each low and high mileage test point for each 
model year tested:
     lf 50 percent or more of all vehicles evaluated in an 
evaporative/refueling/leak emission family for any given model year 
pass the leak standard, testing is complete. This applies to cumulative 
testing for that family throughout the model year for that mileage 
group. This is consistent with the exhaust emission requirements for 
IUVP and EPA believes it is reasonable since vehicles are tested in the 
``as received'' condition from consumers.
     If only one representative of the evaporative/refueling/
leak family is tested in a mileage group for that model year's vehicles 
and it passes the leak standard testing is complete. If that vehicle 
does not pass the leak standard a manufacturer may test an additional 
vehicle to achieve the 50 percent rate.
     If an evaporative/refueling/leak emission family fails to 
achieve the 50 percent rate, it is presumed that the family will enter 
into In-Use Confirmatory Testing Program (IUCP).
    Before IUCP begins, the manufacturer may ask for engineering 
analysis discussions with EPA to evaluate and understand the technical 
reasons for the testing outcomes and the implications for the broader 
fleet. Technical information for these discussions could include but 
will not be limited to detailed system design, calibration, and 
operating information, technical explanations as to why the individual 
vehicles tested failed the leak standard, and comparisons to other 
similar families from the same manufacturer. Relevant information from 
the manufacturer such as data or other information on owner complaints, 
technical service bulletins, service campaigns, special policy warranty 
programs, warranty repair data, state I/M data, and data available from 
other manufacturer specific programs or initiatives could help inform 
understanding of implications for the broader fleet. As part of this 
process a manufacturer could elect to provide evaporative emissions 
SHED test data on the individual vehicle(s) that did not pass the leak 
standard during IUVP.

[[Page 23521]]

With an adequate technical basis, the outcome of this engineering 
analysis discussion could result in an EPA decision not to require IUCP 
testing.
    We will operate within the basic structure of the IUCP program in 
the existing regulations. Prior to commencing IUCP testing the 
manufacturer, after consultation with EPA submits a written plan 
describing the details of the vehicle procurement, maintenance, and 
testing procedures. This plan could include inclusion of a hot soak 
plus diurnal SHED test to supplement leak test results. EPA must 
approve this plan before testing begins. As prescribed in the IUCP 
regulations for exhaust, if five vehicles are tested and all pass the 
leak standard then testing will be complete. If all five vehicles do 
not pass, then five more are tested. More vehicles can be tested at the 
manufacturer's discretion but all testing must be completed within the 
time period specified in the regulations. EPA and the manufacturer then 
enter into discussions regarding interpretation, technical 
understanding, and compliance/enforcement implications of the test 
results, if any.
iv. Optional Test Procedure Approach for IUVP/IUCP
    With the implementation of the OBD regulation changes in Section 
IV.E below regarding evaporative system leak rate monitoring, EPA is 
finalizing an optional approach to a portion of the leak test 
procedure. This optional testing approach is included in the IUVP/IUCP 
testing program for the leak standard, but will not be used for 
certification testing for the leak standard. EPA can also use this 
procedure for conducting compliance assessments. Under this optional 
approach manufacturers will be able to rely upon the operation of their 
OBD evaporative system leak detection hardware and operating protocols 
in lieu of running the stand alone in-use leak test to check for the 
presence of a 0.02 inch leak in the fuel/evaporative system.
    Quite simply, if a vehicle is brought in for IUVP or IUCP testing 
and a scan tool query of the onboard computer indicates that the 
vehicle has successfully completed a full OBD-based evaporative system 
leak monitoring check within the last 750 miles and no evaporative 
system leak problems for any diameter above 0.020 inches are indicated 
(no pending or confirmed diagnostic trouble code(s) P0440, P0442, 
P0446, P0455, P0456, or P0457), the vehicle would be deemed to have met 
and passed the leak standard test requirement. However, if the system 
has not successfully completed a full OBD-based evaporative system leak 
check within 750 miles with no problem indicated then the manufacturer 
will have the option to run its OBD-based evaporative system leak check 
in the laboratory after prescribed preconditioning. This OBD-based 
approach is sometimes used in auto manufacturer dealerships and repair 
facilities to diagnose and fix evaporative system leaks found by the 
OBD system. If the vehicle completes the full OBD-based leak test in 
the laboratory then the vehicle's pass/fail results for the 0.02 inch 
cumulative equivalent diameter orifice will be based on the OBD test 
result. This optional protocol can apply to every leak standard test 
after certification unless not approved by EPA for IUCP under 40 CFR 
1846.01(i). Replicate tests will not be required or allowed but void 
tests could be repeated.
    Furthermore, EPA will permit the manufacturer to run the stand 
alone EPA leak test in several situations. First, manufacturers can 
conduct the stand alone test to confirm that a problem identified by 
the OBD-based evaporative system monitoring leak check is a leak and 
not a problem with the OBD leak monitor itself. Second, a manufacturer 
can run the stand alone EPA leak test to confirm that the leak value 
identified by the OBD system is truly above the level of the leak 
standard. Third, it can be used for vehicles which have not 
successfully completed a full OBD-based evaporative system leak 
monitoring check within the last 750 miles. Fourth, it can be used to 
confirm that a DTC set within the last 750 miles actually indicates the 
presence of a leak(s) greater than the standard. However, if a 
manufacturer elects to use only OBD-based evaporative system leak based 
monitoring in its IUVP testing; these results will be the basis for 
decisions regarding IUCP. As required in the existing IUVP regulations, 
all test data whether OBD based or based on EPA's stand alone test 
procedure must be reported to EPA.
    There may be some advantages to this option since it employs a 
pressure/vacuum approach manufacturers understand and creates positive/
negative pressures manufacturers have accommodated within their fuel/
evaporative system. One potential downside is that under current 
designs vehicle engines will have to be operating to create the 
pressure or vacuum and because the engine is operating this will 
require the OBD-based leak test to be stand alone after the 
preconditioning sequence is complete. This will be more challenging for 
natural vacuum leak detection systems unless extended driving is 
involved to create the fuel system heat needed for a natural vacuum 
event or this is done through a climate chamber or SHED based diurnal 
heat build.
    Allowing for this approach raises at least two implementation 
questions. The first is related to the value of conducting the OBD-
based test for a vehicle with a confirmed or pending leak DTC already 
set in the computer and/or an MIL indicated. In this case, EPA will 
permit the manufacturer to run the OBD-based leak test and/or the stand 
alone EPA leak test or concede that the vehicle will not pass the leak 
standard and count the result. Second is the question of gas caps. This 
is among the most common codes found in OBD records and is often 
related to operator error such as not tightening the gas cap properly. 
Codes of this nature have no value in this leak assessment, so a 
manufacturer will be permitted to correct the problem before testing 
and clear this OBD code before testing or run the stand alone EPA leak 
test.

E. Onboard Diagnostic System Requirements

1. Onboard Diagnostic (OBD) System Regulation Changes--Timing
    EPA first adopted OBD requirements for 1994 and later model year 
LDVs and LDTs. While EPA has extended its requirements from LDVs and 
LDTs to larger and heavier vehicles,\396\ EPA's last broad upgrade to 
its basic OBD regulation was in the 2005 timeframe. Since that time, 
CARB has adopted and the manufacturers have implemented a number of 
additional provisions to enhance the effectiveness of their OBD 
programs. These provisions include new requirements for OBD evaporative 
system leak detection as well as provisions to help insure that systems 
are built and operate as designed over their full useful life, give 
reliable results (find and signal only true deficiencies), and operate 
frequently during in use operation. It is permitted in existing EPA 
regulations and is common practice for the industry to certify their 
OBD systems with CARB and for EPA to accept CARB OBD certifications as 
satisfying EPA requirements. EPA is continuing that practice and we are 
updating our regulations to be

[[Page 23522]]

consistent with the latest CARB regulations.
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    \396\ EPA's OBD regulations for LDVs, LDTs, and MDPVs, are found 
at 40 CFR 86.1806-05. EPA has also adopted OBD requirements for 
incompletes and heavier vehicles (greater than 14,000 lbs GVWR) (see 
74 FR 8324, February 24, 2009 and 40 CFR 86.010-18).
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    EPA proposed to adopt, with a few adjustments, the CARB regulatory 
requirements related to OBD II (see California Code of Regulations 
(CCR) 1968.2 dated May 18, 2010). We received comment from CARB that 
since our NPRM was issued, they were s completing an update of their 
OBD II regulations and that EPA should adopt these provisions in lieu 
of the May 18, 2010 provisions.\397\ We have reviewed these updates and 
concur with the commenters, so we are adopting the provisions 
officially approved by CARBs Office of Administrative Law on July 31, 
2013. We are also adding provisions and continuing the exceptions as 
discussed below. The changes we are adopting do not include any changes 
to requirements for engines used in vehicles over 14,000 lbs GVWR or to 
vehicles over 14,000 lbs GVWR, except for HDGVs optionally certified 
using chassis procedures. To be consistent with the manner in which the 
Tier 3 exhaust emission standards are being implemented for the heavy-
duty vehicles between 8,501 and 14,000 lbs GVWR, the OBD requirements 
will be based on the Job 1 (first production) date for the vehicle/
engine model. If the vehicle/engine model Job 1 date is before the 
fourth anniversary date of the signature of the Tier 3 rule the 
requirements will not be mandatory in that model year. If the Job 1 
date is on or after the fourth anniversary of the signature date of the 
Tier 3 rule the OBD requirements will apply in that model year. The 
Tier 3 OBD requirements will apply to all 8,501-14,000 lb HDVs in the 
2020 model year. To be consistent with the manner in which the Tier 3 
exhaust emission standards.
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    \397\ The latest update of CARB's OBD regulations was adopted on 
July 31, 2013. See section 1968.2 at http://www.arb.ca.gov/msprog/obdprog/obdregs.htm/.
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    We are taking this approach to OBD for three basic reasons. First, 
this is consistent with the goal of a national program and one vehicle 
technology for all 50 states. Second, compliance with the current CARB 
OBDII requirements is now demonstrated technology, compliance with 
these requirements is common within the industry today, and we expect 
that to continue in the future with the 2013 CARB changes. Thus, the 
added burden is minimal since essentially all manufacturers certify 
their CARB OBD systems nationwide with EPA. Third, the latest OBD 
systems run frequently on in-use vehicles to identify potential exhaust 
and evaporative system performance problems, so adopting these 
provisions will create the opportunity for OBD to serve a more 
prominent role in ensuring the Tier 3 emission standards are met in-
use.
    Alignment with the existing CARB OBD II requirements will be 
required by the 2017 MY, except as discussed below. Manufacturers 
requested a phase-in compliance approach in lieu of a fixed compliance 
date, but no specific justification was provided by the commenters and 
EPA could not establish a need for this accommodation since the most 
recent changes to CARB OBDII regulations (2013) did not meaningfully 
affect provisions regarding vehicles/engines under 14,000 lbs GVWR 
which have been in place since 2006. LDVs, LDTs, MDPVs and vehicles 
under 14,000 lbs GVWR already comply with CARB OBDII requirements and 
use the CARB certification as the basis for EPA certification.
    There is an important link between OBD provisions related to 
evaporative emission control system leak monitoring and the leak 
standard. They each provide an important incentive to design fuel/
evaporative systems with fewer propensities to develop leaks in use but 
each addresses the issue from a different perspective. The distinction 
is that the leak standard prohibits leaks of greater than 0.02 inches 
cumulative equivalent diameter, while the OBD evaporative system leak 
monitoring provision requires that the OBD system find leaks larger 
than 0.020 inches cumulative equivalent orifice diameter and notify the 
owner, but with no explicit requirement to repair the problem. Thus 
adopting a 0.020 inch cumulative equivalent orifice diameter aligns 
these two programs and, as discussed above, facilitates the use of OBD 
evaporative system leak monitoring hardware/strategy as an optional 
leak detection test procedure for in-use testing.
    With regard to OBD evaporative system leak detection, EPA received 
comment that we should permit a phase-in for compliance with the 0.020 
inch evaporative system leak monitoring requirement. Even though the 
0.020 inch leak monitoring requirement has been in place since the 
2004MY for CARB OBDII, and essentially manufacturers have met it for 
years, the existing EPA regulation actually only requires monitoring at 
the 0.040 inch threshold level. After considering the comments 
received, EPA is permitting a limited and minimal phase-in for the 
0.020 inch leak detection criterion for the OBD evaporative system 
monitoring requirement. We are permitting this phase-in, because a few 
vehicle models still only meet the 0.040 inch monitoring threshold in 
their Federal configuration and complying with the 0.020 inch CARB OBD 
II requirement entails validating performance in high altitude and cold 
weather regimes not seen in California. Thus, the 0.020 inch 
requirement would be new for those few models currently certified only 
to the EPA evaporative leak monitoring requirement. We are, therefore, 
implementing the following phase-in provision for the 0.020 inch leak 
detection criterion for the OBD evaporative system monitoring 
requirement. First, if a vehicle model meets the 0.020 inch requirement 
in the 2016 model year it is not eligible for the phase-in provision. 
No backsliding is permitted. Second, for manufacturers with models not 
meeting the CARB OBDII evaporative system leak monitoring requirement 
in the 2016 MY (see 13 CCR 1968.2(e)(4)), they will be permitted to 
delay product-wide compliance with the 0.020 inch leak provision of the 
evaporative system monitoring requirements until the 2018 model year by 
engaging in a voluntary early phase-in. This phase-in would begin in 
the 2016 model year and conclude in the 2018 model year at a 100 
percent implementation rate. For example, a manufacturer could delay 
attaining 100 percent compliance with the OBD evaporative system leak 
monitoring requirement until the 2018 model year by complying in the 
2016 model year using a percentage which is at least as large as the 
delay for the 2017 model year (e.g., 40% in 2016 MY, 60% in 2017MY, and 
100% in 2018MY).
2. Revisions to EPA OBD Regulatory Requirements
    As discussed above, we are updating our OBD regulations to be 
consistent with current California OBD II requirements. We are 
incorporating by reference section 1968.2 of the California Code of 
Regulations as adopted July 31, 2013 (13 CCR 1968.2). This includes 
paragraphs (c) through (j) in their entirety. These paragraphs are 
entitled: (c) Definitions, (d) General Requirements, (e) Monitoring 
Requirements for Gasoline/Spark Ignited Engines, (f) Monitoring 
Requirements for Diesel/Compression Ignition Engines, (g) 
Standardization Requirements, (h) Monitoring System Demonstration 
Requirements for Certification, (i) Certification Documentation, (j) 
Production Vehicle Evaluation Testing. The substance of many of these 
provisions is already contained in existing EPA OBD requirements for 
LDVs, LDTs, MDPVs, and complete HDGVs less than 14,000

[[Page 23523]]

lbs GVWR.398 399 EPA will continue to accept certifications 
with CARB OBD requirements as satisfying EPA OBD requirements.
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    \398\ MDVs in the CARB regulations basically incorporate MDPVs 
and complete HDGV less than 14,000 lbs GVWR as defined by EPA.
    \399\ We are not changing the requirement for incompletes and 
vehicles with a GVWR above 14,000 lbs.
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    The most noteworthy changes we are finalizing are summarized below. 
The CCR below is the California Code of Regulations cite for each 
pertinent provision.
     EPA is adding a 0.020 inch leak detection monitoring 
threshold upstream of the purge valve for all 4 vehicle categories LDV, 
LDT, MDPV, and complete HDGVs up to 14,000 lbs GVWR except for those 
with fuel tanks larger than 25 gallons capacity (see 13 CCR 1968.2(e)). 
OBD leak monitoring systems will have to identify, store, and if 
required signal any leak(s) equal to or greater than 0.020 inches 
cumulative equivalent diameter. This will thus include diagnostic 
trouble codes (DTC) P0440, P0442, P0446, P0455, P0456, and P0457.
     EPA is incorporating by reference the full array of rate 
based monitoring requirements (see 13 CCR1968.2 (d)(3)-(6)). Meeting 
the rate based monitoring requirements will help to insure that, even 
with enable criteria, the exhaust and evaporative system monitors run 
frequently enough that on average a problem would be identified and 
signaled to the owner in operation within two weeks. This will help to 
improve the fraction of time monitors are ready to find a potential 
problem.
     EPA is incorporating by reference provisions regarding 
monitoring system demonstration requirements for certification. We are 
incorporating by reference CARB provisions in this area and accepting 
submissions to CARB for purposes of compliance demonstration (see 13 
CCR 1968.2(h)). Adopting current CARB monitoring system demonstration 
requirements assures that monitoring systems operate as designed when 
installed on certification vehicles.
     EPA is incorporating by reference the CARB production 
vehicle evaluation data program. This program requires manufacturers to 
demonstrate that the OBD system functions as designed and certified 
when installed on production vehicles. (See 13 CCR 1968.2(j)).
    In addition, we are adding two new requirements, and retaining 
three minor exceptions. Each of these actions is described separately 
below.
     We are adding the requirement that before certification a 
manufacturer must demonstrate the ability of its OBD leak monitoring 
system to detect and report a 0.020 inch leak in the fuel/evaporative 
system. Current CARB protocols within 13 CCR 1968.2(h)(3) do not 
require this demonstration as part of certification. This requirement 
helps to ensure the OBD system's capability to function as designed and 
the OBD-based evaporative system leak monitoring hardware to be used as 
an optional test procedure for IUVP testing for the leak standard. This 
requirement being added for the same vehicles that are subject to 
monitoring system demonstration requirements for certification under 
CARB OBD regulations under 1968.2(h)(3).\400\ EPA test procedures are 
contained in 40CFR 86.1806-17(b). In the spirit of aligning CARB and 
EPA OBD provisions, if CARB ultimately adopts this demonstration 
requirement and CARB's test procedure provisions fulfill the purpose of 
the EPA requirement, EPA will strongly consider proposing to adopt the 
CARB test procedures in lieu of those in 40 CFR 86.1806-17(b).
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    \400\ Passavant, G. (January, 2014). ``Development of 0.020'' 
Evaporative Leak Monitoring System Demonstration Requirement Test 
Procedure''. Memorandum to the docket.
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    This requirement applies to any vehicle test group certified to the 
OBD 0.020 inch evaporative system leak monitoring requirement. Since 
the regulation requires only a relative few test groups each model year 
per manufacturer, we will permit the manufacturers either to meet the 
requirement for the remainder of its test groups on production vehicles 
of a previous model year which used the identical monitoring hardware 
and strategies or to certify by attestation that each of their 
remaining test groups meets the requirement based on development, 
calibration, and other information. If a manufacturer chooses to 
certify by attestation for some test groups for a given model year, the 
regulations are structured such that over several model years a 
manufacturer would evaluate through testing all test groups as new 
groups are selected in subsequent model years.
     For the OBD evaporative system leak monitoring 
requirement, EPA is establishing a requirement for a scan tool readable 
function (a new InfoType $14 in Service $09 of SAE J1979DA) which can 
be used to obtain the distance traveled since the OBD leak monitoring 
diagnostic was last completed successfully, i.e., the system passed or 
failed (identified any leak above 0.020 inches) during that monitoring 
event (unless it is otherwise already required in other OBD system 
modes). The purpose of this requirement is to facilitate implementation 
of the leak standard within IUVP, by permitting the use of OBD 
evaporative system monitoring results as a tool to make pass/fail 
determinations during IUVP. As discussed in section IV.D above, if a 
vehicle successfully completed an evaporative system leak monitoring 
within the most recent 750 miles then the manufacturer could use this 
result for its IUVP requirement for the leak standard. EPA asked for 
comment on how best to implement this requirement within the OBD 
system, in what model year(s) it should be required and to which 
vehicle classes it should apply.
    Manufacturers supported this requirement, and suggested a lower 
cost approach which we are adopting in the final rule. Rather than 
requiring that the distance and monitoring results be stored in NVRAM 
to avoid false results based on a user induced code clear or battery 
disconnect, the manufacturers suggested that the ``distance since evap 
monitoring decision'' InfoType be reset to the maximum value ($FFFF/
65,535km) when codes are cleared or after a reprogramming event (e.g., 
battery disconnect). The InfoType would be reset to zero km when an 
evaporative monitoring pass/fail decision is later made, allowing the 
mileage to be read directly at IUVP. In the usual situation where no 
user induced code clear or reprogramming event (e.g., battery 
disconnect) occurred, the mileage since the last decision could be read 
directly. In either circumstance, the presence of an evaporative system 
leak related DTC (P0440, P0442, P0446, P0455, P0456, and P0457 or 
manufacturer specific equivalent DTC) will indicate a failure and the 
lack of such a DTC will indicate a pass. The mileage and the pass/fail 
results will then be taken together for purposes of the 750 mile option 
in the IUVP assessment for the leak standard.\401\
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    \401\ Passavant, G. (January, 2014). ``Manufacturer Input on 
Distance Since Last Evaporative Monitoring Decision''. Memorandum to 
the docket.
---------------------------------------------------------------------------

    This requirement applies to all vehicle categories subject to the 
leak test including LDVs, LDTs, MDPVs, and complete HDGVs less than 
14,000 lbs GVWR. Manufacturers commented that this requirement should 
apply only to vehicles/test groups meeting the leak standard. Since the 
leak standard phases-in between 2018 and 2022 model years (2017 for 
manufacturers using the 20/20 evaporative emission option), a 
manufacturer may phase-in compliance with this requirement as well.

[[Page 23524]]

     The minor exceptions which are contained in EPA's existing 
OBD regulations are to be continued. Compliance with 13 CCR 
1968.2(d)(1.4), pertaining to tampering protection is not required. 
Also, the deficiency provisions of 13 CCR 1968.2(k) are not being 
adopted. In addition, demonstration of compliance with 13 CCR 
1968.2(e)(15.2.1)(C), to the extent it applies to the verification of 
proper alignment between the camshaft and crankshaft, will apply only 
to vehicles equipped with variable valve timing. For all model years, 
the deficiency provisions of paragraph (i) of the existing EPA 
regulations apply only to alternative fuel vehicle/engine manufacturers 
selecting this paragraph for demonstrating compliance.
    These changes, taken together will improve the performance, 
reliability, general utility, and effectiveness of OBD systems for Tier 
3 exhaust and evaporative emission controls. Furthermore, these changes 
create the opportunity for OBD evaporative system leak monitoring 
systems to serve a more prominent role in ensuring compliance with the 
leak standard. EPA believes that they can be implemented for minimal 
cost since most manufacturers are meeting them today and will have to 
for LEV III vehicles. The provisions we are incorporating by reference 
give manufacturers the flexibility to seek a revision to the emission 
threshold for a malfunction on any diagnostic required if the most 
reliable monitoring method developed requires a higher threshold to 
prevent significant errors of commission in detecting a 
malfunction.\402\ Any decision on a potential exception would be 
preceded by a consultation between EPA and CARB.
---------------------------------------------------------------------------

    \402\ See 13 CCR 1968.2 (e)(17).
---------------------------------------------------------------------------

    As discussed below, the OBD requirements will apply to small 
entities in the 2022 model year, if they choose to take advantage of 
one of the revised implementation schedules for small volume 
manufacturers and small businesses. However, as is the case for larger 
manufacturers, no backsliding is permitted meaning that if they 
voluntarily meet the OBD requirements on their Federal configurations 
in the 2016 model year as a result of compliance with CARB regulations 
they must continue to meet the requirements on the Federal 
configurations in the 2017 and later model years. Small alternative 
fuel converters will still be able to meet the OBD requirements using 
the provisions of 40 CFR 85, subpart F. Finally, it should be noted 
that as CARB updates its OBD regulations in the future EPA will 
consider these changes and propose to adopt them or incorporate them by 
reference, if appropriate.
3. Provisions for Emergency Vehicles
    It is common for emergency vehicles such as law enforcement, 
medical response, and fire protection vehicles operated by government 
entities to be derived from similar publicly available vehicle 
configurations. However, these vehicles often have chassis 
configurations, auxiliary equipment packages, and performance 
requirements different from the standard publicly available 
configurations. These emergency response vehicles typically meet the 
various EPA emission standards based on the engineering calibrations 
and emission control hardware used in the publicly available 
configuration. OBD requirements also apply to these vehicles and 
occasionally their unique design and/or operating characteristics may 
prevent them from meeting one or more of the various OBD requirements.
    In comments on the NPRM, one manufacturer raised a concern that 
EPA's proposed adoption of the current CARB OBDII requirements for the 
2017 model year would create a compliance problem for two of their law 
enforcement vehicle configurations. These two vehicle configurations 
cannot meet one element of the current CARB OBDII requirements (CCR 
1968.2 (e)(6.2.1)(C)) without compromising the performance expected by 
law enforcement personnel.\403\ To address this issue CARB provided 
these vehicles an exemption from this provision, by permitting it to 
meet Federal requirements as permitted by the California Vehicle Code. 
This solved the problem because the CARB OBD II provision of interest 
did not exist within the Federal OBD requirements at that time.
---------------------------------------------------------------------------

    \403\ See Ford Motor Company comments on the Tier 3 NPRM at EPA/
HQ/OAR/2011/0135/4349.
---------------------------------------------------------------------------

    This raises both a near term and a broader policy issue related to 
emergency vehicles. First, we are incorporating a definition for 
emergency vehicle that is specific to the Tier OBD requirements.\404\ 
Second, with regard to the two law enforcement vehicle configurations 
identified by the manufacturer, EPA has reviewed the manufacturer's 
technical information and agrees with CARB's previous assessment.\405\ 
Thus, EPA will grant the manufacturer a three model year exemption from 
the requirement as requested by the manufacturer (MY2017-2019 
inclusive). Specifically, we are delaying the need to comply with the 
requirements of CCR 1968.2 (e)(6.2.1)(C)--incorporated by reference by 
EPA--until the 2020MY for any emergency vehicle which does not meet the 
requirement in the 2016 model year. This specifically applies to the 
two test groups identified by the commenter. Second, in a broader 
context, there is a need to address the potential future need for a 
deficiency or an exemption for emergency response vehicles. If CARB 
grants a deficiency for emergency response vehicles under CCR 1968.2(k) 
we would expect this to be done in consultation with EPA. Furthermore, 
we are incorporating provisions to address a potential situation where 
an emergency vehicle needs a deficiency (a temporary or permanent 
allowance for manufacturers to be non-compliant with a specific 
requirement of the OBD regulations as long as certain requirements are 
met) or exemption which is not addressed by CARB under CCR 1968.2(k). 
EPA is adopting a provision which authorizes us to address these 
circumstances based on an application from the manufacturer. Under this 
provision, EPA may approve a request for a deficiency or in extreme 
circumstances a temporary or potentially permanent exemption from a 
given OBD requirement. In considering decisions to approve/disapprove 
this request, EPA will consider the provisions of CCR 1968.2 (k)(1) 
plus engineering information and vehicle emission and performance data 
provided by the manufacturer which demonstrates significant vehicle 
engineering or system performance issues (e.g., vehicle speed, 
acceleration, handling, safety, fuel economy, cost) related to 
complying with the OBD requirements.
---------------------------------------------------------------------------

    \404\ For the Tier 3 OBD requirements, emergency vehicle means a 
motor vehicle manufactured primarily for use as an ambulance or 
combination ambulance-hearse or for use by the United States 
Government or a State or local government for fire protection or law 
enforcement.
    \405\ Passavant, G. (January, 2014). Information Related to CARB 
AFRIM OBD Requirements for Emergency Vehicles. Memorandum to the 
docket.
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4. Future Considerations
    EPA and CARB coordinate closely on OBD II requirements. When 
changes to the requirements occur, CARB provisions often precede those 
from EPA. Since LEV III begins before Tier 3, EPA expects that CARB 
will revise any OBD II requirements related to the LEV III before EPA 
would do so for Tier 3. EPA expects to work with CARB on any potential 
changes to OBD II requirements related to LEV III and to consider 
proposing such changes in a

[[Page 23525]]

future action since we expect great commonality between Tier 3 and LEV 
III exhaust and evaporative emission control systems. Two presentations 
related to CARB's initial thinking for LEV III related OBDII revisions 
are available in the docket.\406\ In the interim, for any Tier 3 
exhaust emission bin which does not have a corresponding bin value in 
the Tier 2 program, the threshold for the exhaust emission malfunction 
criteria is that of the next higher bin in the Tier 2 regulation as 
prescribed for the latest model year in CCR 1968.2(e)(1)-(3).
---------------------------------------------------------------------------

    \406\ McCarthy, M., ``CARB Light-duty OBD Regulation Update'', 
SAE 2012 Onboard Diagnostics Symposium, Nov 2012 and Remenus, M., 
``CARB Light-duty OBD Regulation Update'', SAE 2013 Onboard 
Diagnostics Symposium, September 2013.
---------------------------------------------------------------------------

    In the NPRM, EPA discussed the basics of evaporative emission 
control technology and laid out concerns regarding the loss of 
evaporative and refueling emission control which occurs if a canister 
is not purged. This can potentially occur if the purge hardware fails 
or if the flow of purge air through the canister is impeded by foreign 
matter collecting at the inlet port or on the carbon itself, canister 
poisoning due to fuel or water intrusion, or activated carbon breakdown 
from phenomena such as road vibration. Failure of purge hardware is 
already covered by OBD and a recent study indicates that this is a 
relatively rare evaporative system problem.\407\ Failure of the 
activated carbon to purge due to problems such as those mentioned above 
are not covered by OBD. EPA is undertaking a study to better 
characterize the causes and frequency of such potential problems, and 
may propose in a future rulemaking an OBD-based monitoring requirement 
related to activated carbon/canister capture should the study indicate 
a significant frequency of loss of canister efficiency in-use and loss 
in emissions control relative to other evaporative system failure 
modes.
---------------------------------------------------------------------------

    \407\ Weatherby, M., Sabisch, M., Kishan, S. (2014) Analysis of 
Evaporative On-Board Diagnostic (OBD) Readiness and DTCs Using I/M 
Data.
---------------------------------------------------------------------------

    In the NPRM we also asked for comment on several other issues 
related to the role of OBD in future technology fuel/evaporative 
control systems. This included pursuing a monitoring threshold less 
than the 0.020 inches cumulative diameter that we are finalizing in 
this rule for non- pressurized and pressurized fuel systems. We asked 
about the feasibility and cost of requiring the OBD leak detection 
monitoring system to detect and signal the presence of a smaller 
diameter orifice, such as 0.010 inch upstream of the purge valve for a 
pressurized system with a designed in-use operating pressure threshold 
in excess of 0.36 psi (10 inches water). Also, for the pressurized 
system, we asked for comment on a potential provision to require that 
the fuel tank vent to the canister at key off if the OBD system 
identifies a leak. In their comments manufacturers indicated concerns 
about the need for such provisions or their value in reducing emissions 
relative to current requirements. EPA believes both of these provisions 
merit further investigation, but at the present time we lack the data 
to assess the feasibility and emission reduction benefits associated 
with each approach and so are not taking action on them.
    Finally, in the NPRM we sought input on whether the operation of a 
vacuum pump or similar device used to assist or supplement vehicle 
engine vacuum purge or any device otherwise used to enhance or control 
purge flows, rates, or schedules should be required to be monitored as 
part of OBD. In their comments the manufacturers indicated their view 
that this would be covered by current OBD provisions, and we are not 
taking further actions.

F. Emissions Test Fuel

    In-use gasoline has changed considerably since EPA last revised 
specifications for the gasoline used in emissions testing of light- and 
heavy-duty vehicles. Sulfur and benzene levels have been reduced and, 
perhaps most importantly, gasoline containing 10 percent ethanol by 
volume (E10) has replaced non-oxygenated gasoline (E0) across the 
country. This trend has had second-order effects on other gasoline 
properties. In-use fuel is projected to continue to change as refiners 
adjust their gasoline production to reflect the renewable fuel volumes 
required under the RFS2 program, as well as further sulfur reduction 
under the Tier 3 rule.\408\ As a result, we are updating federal 
emission test fuel specifications to better match in-use fuel. The 
revised test fuel specifications apply for exhaust emissions testing, 
fuel economy/greenhouse gas testing, and emissions testing for non-
exhaust emissions (with some exceptions discussed elsewhere in this 
preamble, e.g., for refueling tests in flex-fuel vehicles). The revised 
gasoline specifications, found at Sec.  1065.710 and discussed below, 
apply to emissions testing of light-duty cars and trucks as well as 
heavy-duty gasoline vehicles certified on the chassis test, where the 
vehicles are certified to the Tier 3 standards.\409\
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    \408\ See 78 FR 49794 (August 15, 2013) for the latest renewable 
fuel requirements under the RFS2 program.
    \409\ As discussed elsewhere in Section IV, we are also 
generally requiring the use of Tier 3 test fuel in conducting 
exhaust, evaporative, and refueling emissions testing of heavy-duty 
gasoline engines certified on an engine dynamometer. These could 
include engines installed in incomplete Class 2b and Class 3 
vehicles and engines used in vehicles above 14,000 lb GVWR.
---------------------------------------------------------------------------

1. Gasoline Emissions Test Fuel: Ethanol Content and Volatility
a. Emission Test Fuel Ethanol Content
    In the NPRM, EPA proposed that the emissions test gasoline be 
changed from E0 to E15 as a forward-looking position based on 
indications following the 2011 E15 waiver decision that the market 
would move in that direction.\410\ Since the time when we developed the 
proposal, several relevant factors have led EPA to reconsider that 
position, including limited proliferation on a national scale of 
stations offering E15 and the complexities E15 test fuel would 
introduce for long-term harmonization of the Tier 3 vehicle emission 
regulations with California's LEVIII program (which uses E10 for 
emissions testing).
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    \410\ EPA issued a waiver allowing E15 to be introduced into 
commerce for use in MY 2001 and newer light-duty motor vehicles. On 
July 25, 2011, EPA finalized regulations to mitigate the potential 
for misfueling of vehicles, engines, and equipment not covered by 
the E15 waiver, i.e., MY 2000 and older light-duty motor vehicles, 
all heavy-duty gasoline vehicles and engines, motorcycles, and all 
gasoline-powered nonroad products (which includes boats).\410\ Two 
of the required mitigation measures are a label for fuel pumps that 
dispense E15 to alert consumers to the appropriate and lawful use of 
the fuel and a prohibition on the use of E15 by consumers in 
vehicles not covered by the waiver, excluding flexible fuel vehicles 
(FFVs). For more details, see 76 FR 44406 (July 25, 2011).
---------------------------------------------------------------------------

    We received comments supporting use of E10 as emissions test fuel 
from the automotive and oil industries, as well as states and NGOs 
citing the fact that this was most representative of current market 
conditions. Other stakeholders involved in fuel marketing and 
distribution cited significant infrastructure cost and liability 
concerns in making E15 widely available at existing stations. Ethanol 
industry commenters generally supported E15 certification fuel as 
proposed, but provided no specific timeline on which this blend level 
would become representative of in-use fuel. The most recent surveys of 
the market show that E10 now comprises nearly 100% of in-use gasoline, 
with very small amounts of E0 and E15 being sold in limited areas where 
there is specific interest.\411\ Based on this information and 
considering comments, EPA is finalizing

[[Page 23526]]

E10 as the ethanol blend level in emissions test gasoline for Tier 3 
light-duty and heavy-duty gasoline vehicles. We will continue to 
monitor the in-use gasoline supply and based on such review may 
initiate rulemaking action to revise the specifications for emissions 
test fuel to include a higher ethanol blend level.
---------------------------------------------------------------------------

    \411\ More detail on fuel survey data is available in Chapter 3 
of the Regulatory Impact Analysis.
---------------------------------------------------------------------------

    As discussed above in Sections IV.A.7.d (tailpipe emission testing) 
and IV.C.5.b (evaporative emission testing), we are requiring all 
light-duty and chassis-certified heavy-duty gasoline vehicles to be 
certified to Tier 3 standards on federal E10 test fuel. As described in 
those sections, EPA will accept emission certification test results 
performed according to CARB's LEVIII procedures including CARB's E10 
test fuel. Confirmatory and in-use exhaust or evaporative testing of 
vehicles certified on CARB's E10 test fuel will be performed using that 
same test fuel through MY 2019. After MY 2019, EPA will continue the 
practice of accepting emission data at certification on the LEVIII test 
fuel; however confirmatory and in-use testing may be performed using 
Tier 3 E10 test fuel at the discretion of the Agency.
b. Certification Fuel Volatility (RVP) Specification
    In deciding to finalize E10 as the emissions test fuel it is 
appropriate to consider whether a change in the volatility of the test 
fuel is warranted, typically expressed as in pounds per square inch 
(psi) Reid Vapor Pressure (RVP) or dry vapor pressure equivalent 
(DVPE). The Clean Air Act (Section 211(h)(1)) sets a national limit on 
summertime RVP in northern conventional gasoline areas of 9.0 psi to 
control ozone pollution. However, Congress included a waiver allowance 
(Section 211(h)(4)) granting an additional 1 psi RVP to 10% ethanol 
blends, meaning that E10 could have an RVP up to 10 psi in these 
conventional gasoline areas unless specifically prohibited by state or 
local rules. Under Section 211(h)(4), E15 is not covered by the waiver 
and thus is restricted to 9 psi nationwide.
    The automakers submitted comments that recommended leaving the RVP 
of emissions test fuel at 9 psi on the basis that raising the 
specification to 10 psi would increase the stringency of the proposed 
evaporative emission standards significantly. We agree that the 
resulting increased vapor generation rates during the refueling test 
would increase emissions (by about 10 percent and during the hot soak, 
diurnal, canister bleed, and running loss tests by as much as 25 
percent in total). While the likely increase in canister volume in 
response to higher certification fuel RVP would not be difficult for 
automakers to accommodate in most cases, there are additional 
uncertainties regarding cost and feasibility of strategies for removing 
the larger vapor loads from the canister during vehicle operation 
(vapor ``purging''). Some vehicles have adequate engine vacuum 
available to accomplish the increased vapor purge, while others may 
require new or innovative approaches to increase purge volume or 
efficiency (as discussed in the evaporative emissions technology 
discussion in Section IV.C.3).
    Several other commenters, such as NGOs and environmental groups, 
supported setting certification gasoline RVP to 10 psi to be 
representative of the worst-case volatility vehicles may see in the 
market, making the test procedure more stringent than in the proposed 
program and further reducing evaporative emissions.
    Raising the certification test fuel RVP to 10 psi would also impact 
the equivalency of CARB and EPA hot soak plus diurnal evaporative 
emission test procedures. (California requires the use of 7 psi RVP 
test fuel, which, in conjunction with higher test temperatures, 
produces equivalent results to the federal test procedures using 9 psi 
fuel.) If we were to adopt 10 psi test fuel, we would likely need to 
develop and adopt new test procedure adjustments in order to maintain 
the equivalency of CARB and EPA evaporative procedures (and allow 
reciprocal acceptance of test data generated under either agency's 
program).
    In addition, the 1 psi RVP waiver for E10 does not apply to 
gasoline with higher ethanol levels; for example, under current 
regulations E15 is subject to an RVP limit of 9 psi. If EPA had adopted 
10 psi test fuel in this rule and if gasoline with higher ethanol 
levels than E10 were to become commonly used nationwide, maintaining 
alignment with in-use fuel could necessitate a change in emissions test 
fuel back to 9 psi.
    A review of 2011 gasoline batch data submitted to EPA shows that 
just under half of summertime gasoline was conventional gasoline at 10 
psi RVP. An additional third was RFG at approximately 7 psi RVP, with 
the remainder having intermediate RVPs under local volatility control 
programs. A volume-weighted average of these data is approximately 8.7 
psi RVP. Thus, an emissions test gasoline volatility at 9 psi aligns 
well with the average nationwide in-use RVP today. In addition, 
virtually all of the areas that have elevated summertime ozone levels 
where excess evaporative VOC emissions would be of greatest concern 
already control in-use gasoline RVP to levels less than 9 psi. 
Furthermore, under section 211(a)(5), governors can request that the 1 
psi waiver for E10 not apply in their state if it causes an emissions 
increase that contributes to air pollution. Any state exercising this 
authority would have in-use E10 RVP levels limited to 9 psi.
    After considering these technical and policy issues in the context 
of the information available and comments received, we conclude that 
the most appropriate approach is to set an RVP of 9 psi for Tier 3 
emissions test fuel.
c. Durability Test Fuel
    EPA's motor vehicle emissions standards typically require a level 
of performance over a specified test procedure, with emissions measured 
while the engine or the vehicle is operated using the specified test 
fuel and operated in a specified manner. The test fuel specifications 
typically apply for all emissions testing used to determine compliance 
with the standard, including emissions testing to obtain a certificate 
of conformity, as well as compliance testing for newly produced or in-
use engines or vehicles. While this test fuel is sometimes referred to 
as ``certification fuel,'' the test fuel specifications are not limited 
to certification related emissions testing, but also apply to 
compliance related emissions testing after the certificate of 
conformity has been issued. The certification process also typically 
involves a process to ensure that the emissions controls system is 
durable over the regulatory useful life of the vehicle or engine. This 
can involve long-term or accelerated aging of a vehicle or engine prior 
to emissions testing. The fuel used for such aging is commonly referred 
to as service accumulation or durability fuel, and in many cases is 
specified as commercial gasoline that will be generally available 
through retail outlets (Sec.  86.113-04(a)(3)), or in some cases may be 
specified as gasoline which contains ethanol in, at least, the highest 
concentration permissible in gasoline under federal law and that is 
commercially available in any state in the United States, such as for 
durability aging of evaporative emissions system (Sec.  86.1824-08(f)). 
EPA is not changing the specifications for fuel used during durability 
related aging that is part of the certification process. The regulatory 
changes in this final rule only apply to the test fuel used during 
emissions

[[Page 23527]]

testing, both for purposes of certification and for later compliance 
related testing.
    We are not changing the exhaust or evaporative durability fuel 
requirements outlined in the provisions of Sec.  86.113-04(a)(3), 
except to remove the minimum sulfur content (15 ppm) specified at Sec.  
86.113-04(a)(3)(i). Those provisions require that ``[u]nless otherwise 
approved by the Administrator, unleaded gasoline representative of 
commercial gasoline that will be generally available through retail 
outlets must be used in service accumulation.'' We expect that 
manufacturers will use service accumulation fuels that are generally 
representative of the national average in-use fuels (or worst case for 
durability) during the model year which is being certified, including, 
for example, the ethanol content (for exhaust emissions), sulfur level, 
and fuel additive package. For exhaust emission bench aging durability 
programs as allowed under the provisions of Sec.  86.1823-08(d) and 
(e), the bench aging program should be designed using good engineering 
judgment to account for the effects of in-use fuels on exhaust 
emissions, including the effects of future in-use fuels on catalytic 
converters, oxygen sensors, fuel injectors, and other emission-related 
components.
    For evaporative emissions, durability fuel requirements are the 
same as for exhaust emissions (as outlined above), plus an additional 
requirement in the provisions of Sec.  86.1824-08(f), that the service 
accumulation fuel ``contains ethanol in, at least, the highest 
concentration permissible in gasoline under federal law and that is 
commercially available in any state in the United States. Unless 
otherwise approved by the Administrator, the manufacturer must 
determine the appropriate ethanol concentration by selecting the 
highest legal concentration commercially available during the calendar 
year before the one in which the manufacturer begins its mileage 
accumulation.'' Thus, we expect that E15 service accumulation fuel will 
be used for whole vehicle evaporative durability programs. Similarly, 
evaporative bench aging durability programs allowed under the 
provisions of Sec.  86.1824-08(d) and (e), should be designed using 
good engineering judgment to account for the durability effects of in-
use fuels on evaporative emissions, bleed emissions, and leakage 
emissions.
2. Other Gasoline Emissions Test Fuel Specifications
    Where possible, we are changing test fuel specifications to be 
consistent with CARB's LEV III gasoline test fuel specifications.\412\ 
In addition to the ethanol and volatility specifications discussed 
above, below is an overview of some of the key changes. Table IV-26 
provides a summary of the new test fuel properties. For more 
information on how we arrived at the test fuel property ranges and ASTM 
test methods, refer to Chapter 3 of the RIA.
---------------------------------------------------------------------------

    \412\ LEV III test procedures, including a description of test 
fuel, can be found at 13 CCR 1961.2.
---------------------------------------------------------------------------

     Octane--lowering gasoline octane to around 87 (R+M)/2 to 
be representative of in-use fuel, i.e., regular-grade E10 gasoline. 
Manufacturers can continue to use high-octane gasoline for testing of 
premium-required \413\ vehicles and engines as well as for testing 
unrelated to exhaust emissions. Historically, the high octane rating of 
test fuel has not had any real emissions implications. However, as 
manufacturers begin introducing new advanced vehicle technologies 
(e.g., turbocharged/downsized), this may no longer be the case. For 
those vehicles where operation on high-octane gasoline is required by 
the manufacturer, we are allowing the manufacturer to test on a fuel 
with a minimum octane rating of 91 (R+M)/2 (in lieu of the 87 (R+M)/2 
specified for general test fuel). According to the regulations found at 
Sec.  1065.710(d), vehicles or engines are considered to require 
premium fuel if they are designed specifically for operation on high-
octane fuel and the manufacturer requires the use of premium gasoline 
as part of their warranty as indicated in the owner's manual. Cases 
where premium gasoline is not required but is recommended to improve 
performance would not qualify as a vehicle or engine that requires the 
use of premium fuel. For qualifying vehicles and engines, all emission 
tests must use the specified high-octane fuel. For vehicles and engines 
certified on high-octane gasoline, all EPA confirmatory and in-use 
testing would also be conducted on high-octane gasoline. All other test 
fuel specifications are the same as those described in Table IV-26.
---------------------------------------------------------------------------

    \413\ Premium-required defined at Sec.  1065.710(d).
---------------------------------------------------------------------------

     Distillation Temperatures--adjusting gasoline distillation 
temperatures to better reflect in-use E10 gasoline. This includes minor 
T10, T90 and FBP adjustments based on AAM fuel surveys and refinery 
batch data. These data show that T50 varies widely in in-use fuel, from 
around 150[emsp14][deg]F to 220[emsp14][deg]F. Adopting a wide 
specification range for test fuel may have undesirable effects on 
consistency of results between facilities and over time. Therefore, we 
have chosen a range of 190-210[emsp14][deg]F to maintain some overlap 
with CARB's specification of 205-215[emsp14][deg]F but extending 
somewhat lower to better capture federal in-use fuel. For more 
information on how we arrived at the distillation temperatures in Table 
IV-26, refer to Chapter 3 of the RIA.
     Sulfur--lowering the sulfur content of test fuel to 8-11 
ppm to be consistent with our new Tier 3 gasoline sulfur standards. The 
10 ppm annual average sulfur standard for in-use gasoline standard is 
expected to result in two-thirds less sulfur nationwide so it is 
appropriate to lower the gasoline test fuel specification in concert.
     Benzene--setting a benzene test fuel specification of 0.5-
0.7 volume percent to represent in-use fuel under the MSAT2 
regulations.\414\ The MSAT2 standards, which took effect January 1, 
2011, limit the gasoline pool to 0.62 volume percent benzene on 
average.
---------------------------------------------------------------------------

    \414\ 72 FR 8434 (February 26, 2007).
---------------------------------------------------------------------------

     Total Aromatics--lowering the range of aromatics content 
in the test fuel to better match today's in-use E10 gasoline, and 
narrowing the range to limit variability of results. Data from recent 
gasoline batch data as well as AAM surveys support a specification of 
22-26 volume percent.\415\
---------------------------------------------------------------------------

    \415\ More details on fuel property analysis are available in 
Chapter 3 of the RIA.
---------------------------------------------------------------------------

     Distribution of Aromatics--in addition to total aromatics 
and benzene, the updated test fuel requirements place boundaries on the 
distribution of aromatics by carbon number (i.e., prescribed volume 
percent ranges for each of C7, C8, C9, and C10+ hydrocarbons). There is 
evidence that the heaviest aromatics in gasoline contribute 
disproportionately to PM emissions, so compliance with emission 
standards should be demonstrated on fuel with a composition 
representative of in-use gasoline. For more information on the 
aromatics specifications, refer to Chapter 3 of the RIA.
     Olefins--adjusting the olefins specification to a range of 
4-10 volume percent to better match in-use E10 gasoline.
     Other Specifications--adding distillation residue, total 
content of oxygenates other than ethanol, copper corrosion, solvent-
washed gum, and oxidation stability specifications to better control 
other performance properties of test fuel. These specifications are 
consistent with ASTM's D4814 gasoline specifications and CARB's LEV III 
test fuel requirements.

[[Page 23528]]

     Updates to Gasoline Test Methods--updating some of the 
gasoline test methods previously specified in Sec.  86.113 with more 
appropriate, easier to use, or more precise test methods for ethanol-
blended gasoline. Key changes include replacement of ASTM D323 with 
ASTM D5191 for measuring vapor pressure; replacement of ASTM D1319 with 
ASTM D5769 for measuring aromatics and benzene; and replacement of ASTM 
D1266 with three alternative ASTM test methods (D2622, D5453 or D7039) 
for measuring sulfur.

                                                  Table IV-26--Gasoline Emissions Test Fuel Properties
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Specification
                                                           ------------------------------------------------------
             Property                        Unit                             Low- temperature    High altitude           Reference procedure \a\
                                                             General testing       testing           testing
--------------------------------------------------------------------------------------------------------------------------------------------------------
Antiknock Index (R+M)/2..........  .......................            87.0--88.4 \b\                87.0 Minimum  ASTM D2699 and D2700.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sensitivity (R-M)................  .......................                       7.5 Minimum                      ASTM D2699 and D2700.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dry Vapor Pressure Equivalent      kPa (psi)..............         60.0-63.4         77.2-81.4         52.4-55.2  ASTM D5191.
 (DVPE) c, d.                                                      (8.7-9.2)       (11.2-11.8)         (7.6-8.0)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Distillation \e\
    10% evaporated...............  [deg]C ([deg]F)........             49-60             43-54             49-60  ASTM D86.
                                                                   (120-140)         (110-130)         (120-140)
                                                           ------------------------------------------------------
    50% evaporated...............  [deg]C ([deg]F)........                     88-99 (190-210)
    90% evaporated...............  [deg]C ([deg]F)........                    157-168 (315-335)
    Evaporated final boiling       [deg]C ([deg]F)........                    193-216 (380-420)
     point.
Residue..........................  milliliter.............                       2.0 Maximum
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total Aromatic Hydrocarbons......  volume %...............                        21.0-25.0                       ASTM D5769.
C6 Aromatics (benzene)...........  volume %...............                         0.5-0.7
C7 Aromatics (toluene)...........  volume %...............                         5.2-6.4
C8 Aromatics.....................  volume %...............                         5.2-6.4
C9 Aromatics.....................  volume %...............                         5.2-6.4
C10+ Aromatics...................  volume %...............                         4.4-5.6
--------------------------------------------------------------------------------------------------------------------------------------------------------
Olefins \5\......................  mass %.................                        4.0-10.0                        ASTM D6550.
Ethanol blended..................  volume %...............                        9.6-10.0                        See Sec.   1065.710(b)(3).
Ethanol confirmatory \f\.........  volume %...............                        9.4-10.2                        ASTM D4815 or D5599.
Total Content of Oxygenates Other  volume %...............                       0.1 Maximum                      ASTM D4815 or D5599.
 than Ethanol \f\.
Sulfur...........................  mg/kg..................                        8.0-11.0                        ASTM D2622, D5453 or D7039.
Lead.............................  g/liter................                     0.0026 Maximum                     ASTM D3237.
Phosphorus.......................  g/liter................                     0.0013 Maximum                     ASTM D3231.
Copper Corrosion.................  .......................                      No. 1 Maximum                     ASTM D130.
Solvent-Washed Gum Content.......  mg/100 milliliter......                       3.0 Maximum                      ASTM D381.
Oxidation Stability..............  minute.................                      1000 Minimum                      ASTM D525.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ ASTM procedures are incorporated by reference in Sec.   1065.1010. See Sec.   1065.701(d) for other allowed procedures.
\b\ Octane specifications apply only for testing related to exhaust emissions. For engines or vehicles that require the use of premium fuel, as
  described in paragraph (d) of this section, the adjusted specification for antiknock index is a minimum value of 91.0; no maximum value applies. All
  other specifications apply for this high-octane fuel.
\c\ Calculate dry vapor pressure equivalent, DVPE, based on the measured total vapor pressure, pT, using the following equation: DVPE (kPa) =
  0.956pT--2.39 (or DVPE (psi) = 0.956pT--0.347. DVPE is intended to be equivalent to Reid Vapor Pressure using a different test method.
\d\ Parenthetical values are shown for informational purposes only.
\e\ The reference procedure prescribes measurement of olefin concentration in mass %. Multiply this result by 0.857 and round to the first decimal place
  to determine the olefin concentration in volume %.
\f\ The reference procedure prescribes concentration measurements for ethanol and other oxygenates in mass %. Convert results to volume % as specified
  in Section 14.3 of ASTM D4815.

    As mentioned earlier, we will continue to allow manufacturers to 
test vehicles on premium-grade gasoline should the vehicles require it. 
In addition, since we cannot predict all future changes in gasoline 
vehicle technologies and in-use fuels, we will allow vehicle 
manufacturers to specify an alternative test fuel under certain 
situations. Under this provision, if manufacturers were to design 
vehicles that required operation on a higher octane, higher ethanol 
content gasoline (e.g., dedicated E30 vehicles or FFVs optimized to run 
on E30 or higher ethanol blends), under 40 CFR 1065.701(c), they can 
petition the Administrator for approval of a higher octane, higher 
ethanol content test fuel if they can demonstrate that such a fuel 
would be used by the operator and would be readily available 
nationwide, vehicles would not operate appropriately on other available 
fuels, and such a fuel would result in equivalent emissions 
performance. For vehicles certified on high-octane, high-ethanol 
gasoline, all EPA confirmatory and in-use testing would also be 
conducted on high-octane, high-ethanol gasoline. This could help 
manufacturers who wish to raise compression ratios to improve vehicle 
efficiency as a step toward complying with the 2017 and later light-
duty greenhouse gas and CAFE standards. This in turn could help

[[Page 23529]]

provide a market incentive to increase ethanol use beyond E10 and 
enhance the environmental performance of ethanol as a transportation 
fuel by using it to enable more fuel efficient engines.
    We received comments in general support of allowing certification 
on higher octane fuels if the vehicles require it, although some 
commenters believe that the criteria EPA is specifying for such an 
allowance are too severe. We have considered these comments, and as 
discussed in the Summary and Analysis of Comments document, we continue 
to believe that our approach is appropriate, and we are finalizing 
these provisions as proposed.
3. Flexible Fuel Vehicle Exhaust Emissions Test Fuel
    We are also finalizing specifications for the fuel used in flexible 
fuel vehicles (FFV) exhaust emissions testing including certification 
testing. EPA is establishing specifications for FFV test fuel to 
resolve confusion and inconsistency among FFV manufacturers in carrying 
out their certification and other testing requirements and to ensure 
that FFV emissions are appropriately controlled over the range of in-
use fuels. The FFV exhaust emissions test fuel specifications will 
phase in on the same schedule as the E10 standard gasoline test fuel 
specifications for light- and heavy-duty gasoline vehicles (described 
in Section IV.F.4). These FFV exhaust emissions test fuel 
specifications may be used voluntarily prior to when they are required 
to be used. The base fuel stock used to formulate FFV exhaust emissions 
test fuel must comply with the specifications finalized today for the 
standard E10 emissions test fuel as described in preamble Sections 
IV.F.1 and 2. This practice avoids the need to specify the ranges for a 
number of fuel parameters as we have done for gasoline test fuel in 
Table IV-26 and helps to minimize the number of test fuels that a 
vehicle manufacturer must store. Denatured fuel ethanol (DFE) that 
meets the specifications discussed in preamble Section V.G. must be 
blended into this base fuel stock to attain an ethanol content of 80 to 
83 volume percent in the finished test fuel. Commercial grade normal 
butane can be added as a volatility trimmer to meet a 6.0 to 6.5 psi 
RVP specification for the finished test fuel.\416\
---------------------------------------------------------------------------

    \416\ The specifications for commercial grade butane are 
contained in 40 CFR 80.82.
---------------------------------------------------------------------------

    As an alternative to the use of DFE to manufacture FFV test fuel, 
neat (undenatured) fuel grade ethanol can be used. As an alternative to 
using a finished E10 standard gasoline test fuel in the manufacture of 
FFV test fuel, the gasoline blendstock used by the fuel provider to 
produce a compliant E10 test fuel can also be used to manufacture the 
FFV test fuel. This would allow ethanol to be blended only once to 
produce FFV test fuel. In such cases, a sample of the subject gasoline 
blendstock must be tested after the addition of ethanol to produce a 
finished standard E10 gasoline test fuel to demonstrate that the blend 
meets all of the requirements for standard gasoline test fuel described 
in Section IV.F.
    The public comments were supportive of EPA establishing 
specifications for FFV exhaust emissions test fuel. However, some 
commenters stated that the ethanol content and RVP specifications for 
FFV exhaust emissions test fuel should be based on typical values for 
in-use E85.\417\ Automobile manufacturers commented that EPA should 
wait to finalize FFV test fuel specifications until a review of in-use 
E51-83 fuel quality can be completed in later 2013. They stated that 
this would allow the FFV test fuel specifications to be representative 
of the change to in-use ``E85'' composition since ASTM reduced the 
minimum ethanol concentration from 68 to 51 volume percent.
---------------------------------------------------------------------------

    \417\ The term ``E85'' has historically been used to describe an 
ethanol blend for use in FFVs with a maximum ethanol content of 83 
volume percent and satisfying other fuel parameter specifications 
established by ASTM International. ASTM D5798-13, ``Standard 
Specification for Ethanol Fuel Blends for Flexible-Fuel Automotive 
Spark-Ignition Engines''.
---------------------------------------------------------------------------

    Substantial publicly available literature exists to demonstrate 
that the ethanol content of fuel used in FFVs has a significant effect 
on vehicle emissions. The effect of ethanol content on FFV emissions 
becomes more pronounced with increasing ethanol concentration. The 
current ASTM specification for E85 provides that the ethanol content of 
E85 may vary from 51 to 83 volume percent depending on climactic 
conditions.\418\ Consistent with our long standing policy regarding the 
exhaust emissions testing of FFVs, we continue to believe that FFVs 
must comply with all emissions control requirements while using any 
fuel that they have the potential to operate on in-use. This ensures 
vehicles are designed and calibrated for emissions performance across 
the full range of potential in-use fuel formulations. FFVs are required 
to have exhaust emissions certification testing conducted using both 
E10 and FFV exhaust emissions test fuel to account for the effect on 
emissions of the full range of potential ethanol blend formulations. To 
ensure that FFV certification testing adequately accounts for in-use 
emissions performance, we are finalizing the ethanol content of FFV 
exhaust emissions test fuel at 81-83 volume percent as proposed. 
Exhaust emissions testing conducted using a fuel containing 81-83 
volume percent ethanol will provide results that represent the effect 
of ethanol on FFV emissions performance when this effect is most 
pronounced. The complimentary emissions certification testing required 
for FFVs on E10 will ensure that the effect on FFV emissions from the 
full range of potential in-use ethanol concentrations is represented. 
Given the need to ensure that FFV emissions certification testing is 
representative of the full range of potential in-use ethanol blends, it 
would be inappropriate to set the required ethanol concentration for 
FFV emissions test fuel based on typical in-use levels as suggested by 
some of the commenters.
---------------------------------------------------------------------------

    \418\ ASTM International D5798-13, ``Standard Specification for 
Ethanol Fuel Blends for Flexible-Fuel Automotive Spark-Ignition 
Engines''.
---------------------------------------------------------------------------

    Similarly, the RVP of FFV exhaust emissions test fuel must assure 
emissions performance over the range of in-use fuels. When ethanol and 
gasoline are blended to produce high level ethanol blends, the RVP can 
be and often is very low. As a result, ASTM instituted a minimum RVP 
for E51-83 of 5.5 psi. Given that low volatility fuels can make the 
control of cold start emissions more challenging, we are finalizing the 
RVP of FFV exhaust emissions test to be near the minimum RVP that will 
be encountered in-use. The 6.0 to 6.5 RVP specification finalized today 
will help to ensure that FFVs are designed and calibrated to maintain 
their exhaust emissions performance across the range of in-use fuels.
    The levels of other fuel parameters for in-use E51-83 are 
determined by the levels of these parameters present in the gasoline 
blendstock used as diluted by the addition of ethanol. Therefore, we 
believe that requiring that the levels of these other fuel parameters 
present in FFV exhaust emissions test fuel be determined by the 
dilution of the levels present in standard gasoline emissions test fuel 
appropriately reflects their potential effect on emissions performance. 
Given the considerations discussed above in determining the FFV exhaust 
emissions test fuel specifications finalized today, we do not believe 
that there would be a substantial benefit in waiting for the completion 
of the E51-83 fuel quality survey currently

[[Page 23530]]

underway to finalize FFV test fuel specifications.
    As discussed in preamble Section V.H., the Agency is also 
considering finalizing the in-use fuel quality standards for higher 
level ethanol blends on which we sought comment in the NPRM. These 
standards included an in-use RVP standard of 9.0 psi matching that of 
conventional gasoline. They also contained provisions to allow the 
production of high-level ethanol blends for use in FFVs from natural 
gasoline and other higher volatility components. Were we to finalize 
these in-use standards, we would also consider raising the RVP for the 
FFV exhaust emissions test fuel.
    We are revising the definition of ``alcohol'' in 40 CFR part 600 to 
align with the change in the ASTM specification for in-use fuels. Under 
the revised regulation, we consider an alcohol-fueled vehicle to be one 
that is designed to operate exclusively on a fuel containing 51 percent 
or more ethanol or other alcohol by volume. This is not intended to 
change the applicability, procedures, or requirements for the fuel 
economy provisions in 40 CFR part 600.
4. Implementation Schedule
    As described earlier in this Section IV, we are establishing Tier 3 
exhaust and evaporative emission standards. The changes in the 
specifications for test fuel apply to vehicles certified to these new 
standards. The program is designed to transition to the new test fuel 
during the first few years as the Tier 3 standards are phasing in. 
Testing requirement with the new Tier 3 test fuel starts with light-
duty vehicles certified to Tier 3 bin standards at or below Bin 70, and 
heavy-duty vehicles certified to Tier 3 bin standards at or below Bin 
250 (for Class 2b) and Bin 400 (for Class 3). For light-duty vehicles, 
Table IV-27 below describes the implementation schedule of the new Tier 
3 gasoline test fuels for each of the program elements in addition to 
the all the gasoline test fuel options available during the transition 
period. Table IV-3 below similarly describes the heavy-duty gasoline 
vehicle test fuel implementation schedule and gasoline test fuel 
options. The new Tier 3 PM requirements for both light-duty vehicles 
and heavy duty vehicles which phase-in independent of other vehicle 
exhaust emission requirements must be met using the certification test 
fuel for meeting the NMOG+NOX standards.
    Starting with model years 2020 for light-duty and 2022 for heavy-
duty, all manufacturers will use the new test fuel for all exhaust 
emission testing (with the exception of small volume manufacturers and 
small businesses, which can delay using the new test fuel for all 
vehicles until model year 2022). Manufacturers also need to comply with 
cold temperature CO and NMHC standards using the new test fuel for any 
models that use the new test fuel for meeting the light-duty Tier 3 
exhaust emission standards as indicated in the tables below. These same 
tests will also provide the basis for meeting GHG requirements under 40 
CFR part 86 and fuel economy requirements under 40 CFR part 600, as 
described in the following section.

                  Table IV-27--Exhaust Emissions Gasoline Test Fuels for LDVs, LDTs, and MDPVs
----------------------------------------------------------------------------------------------------------------
                                        Test purpose:                           Test cycles
                                      demonstration of   -------------------------------------------------------
    Emission compliance program       compliance to the                           Cold CO and
                                    emissions standards:   FTP City/HWFE/SFTP         NMHC        High altitude
----------------------------------------------------------------------------------------------------------------
Tier 2............................  Certification.......  (1)(2)(3)(4)........              (1)              (1)
                                    Confirmatory and In-  Certification fuel                (1)              (1)
                                     use.                  and/or (1)*.
Tier 3 Early 2015 to 2017.........  Certification.......  (1)**(2)***(3)(4)...         (1)**(3)         (1)**(3)
                                    Confirmatory and In-  Certification fuel..         (1)**(3)         (1)**(3)
                                     use.
Tier 3 phase-in 2017 to 2019......  Certification.......  (1)**(2)***(3)(4)...         (1)**(3)         (1)**(3)
                                    Confirmatory and In-  Certification fuel..         (1)**(3)         (1)**(3)
                                     use.
Tier 3 complete 2020+.............  Certification.......  (3)(4)..............              (3)              (3)
                                    Confirmatory and In-  Certification fuel                (3)              (3)
                                     use.                  and/or (3)*.
----------------------------------------------------------------------------------------------------------------
Fuels: (1) Tier 2 (2) LEV II (3) Tier 3 E10 (4) LEV III E10
* EPA accepts the use of California certification fuels (or Tier 3 E10 for Tier 2 certification) but
  manufacturer must comply on the program specific Federal fuel. EPA may perform or require manufacturer testing
  on the Federal fuel.
** Fuel (1) only allowed for Bins 160, 125, 110, 85.
*** Fuel (2) only allowed for carryover SULEV 150k exhaust.


                   Table IV-28--Exhaust Emissions Gasoline Test Fuels for Heavy Duty Vehicles
----------------------------------------------------------------------------------------------------------------
                                                Test purpose:                        Test cycles
                                              demonstration of      --------------------------------------------
      Emission compliance program             compliance to the
                                             emissions standards         FTP City/HWFE/SFTP       High altitude
----------------------------------------------------------------------------------------------------------------
Pre-Tier 3.............................  Certification.............  (1)(2)(3)(4)..............              (1)
                                         Confirmatory and In-use...  Certification fuel and/or               (1)
                                                                      (1)*.
Tier 3 Early 2016 to 2017..............  Certification.............  (1)** (3)(4)..............         (1)**(3)
                                         Confirmatory and In-use...  Certification fuel........         (1)**(3)
Tier 3 phase-in 2018 to 2021...........  Certification.............  (1)** (3)(4)..............         (1)**(3)
                                         Confirmatory and In-use...  Certification fuel........         (1)**(3)
Tier 3 complete 2022+..................  Certification.............  (3)(4)....................              (3)
                                         Confirmatory and In-use...  Certification fuel and/or               (3)
                                                                      (3)*.
----------------------------------------------------------------------------------------------------------------
Fuels: (1) Tier 2 (2) LEV II (3) Tier 3 E10 (4) LEV III E10
* EPA accepts the use of California certification fuels (or Tier 3 E10 for Tier 2 certification) but
  manufacturer must comply on the program specific Federal fuel. EPA may perform or require manufacturer testing
  on the Federal fuel.
** Fuel (1) only allowed for Bins 340, 395, 570, 630.


[[Page 23531]]

    Additionally, heavy-duty gasoline engines (HDGEs) not subject to 
new Tier 3 exhaust emission standards (those certified for exhaust 
emissions using an engine dynamometer) are required to be certified on 
Tier 3 fuel by MY 2022. Further discussion can be found in Section 
IV.C.4.c.
    For evaporative emission testing, manufacturers will need to use 
the new test fuel for any models that are to be certified to the Tier 3 
evaporative emission standards. To the extent that these models are 
different than those used for exhaust emission testing with the new 
test fuel, manufacturers will need to do additional testing to 
demonstrate compliance with all applicable standards. They may 
alternatively use the new test fuel earlier than the regulations 
specify to avoid additional testing. We further require that 
manufacturers submit certification data based on the new test fuel to 
demonstrate compliance with refueling emission standards for any 
vehicles that are certified to the Tier 3 evaporative emission 
standards.
5. Implications of Emission Test Fuel Changes on CAFE Standards, GHG 
Standards, and Fuel Economy Labels
a. Test Fuel
    Under regulations in 40 CFR part 600, vehicles use the same test 
fuel in emission testing conducted for CAFE standards, greenhouse gas 
(GHG) emissions, and the fuel economy label as that used for emission 
testing for criteria pollutants. This includes the test fuel used for 
testing on all five cycles (FTP, highway fuel economy test (HFET), 
US06, SC03, and Cold FTP). In the Tier 3 NPRM, EPA proposed a change in 
emissions test fuel used to determine compliance with criteria 
pollutant standards and this test fuel change would also apply to CAFE 
and GHG standards and the fuel economy label such that a common test 
fuel under 40 CFR part 600 was retained. At the same time, EPA 
indicated its commitment to the principle that the change in test fuel 
would not affect the stringency of the CAFE or GHG standards and that 
the labeling calculations would be updated in a future action to 
reflect the change in test fuel properties.
    The NPRM indicated that more data and time were needed to assess 
the effects on stringency and implementation of these programs. While 
EPA's initial review of available data suggested that the change in 
test fuel would not impact the GHG standards, more time and data were 
needed to confirm this initial view regarding the GHG standards and to 
determine what adjustments if any would need to be made to the CAFE 
program and fuel economy label calculation procedures to account for 
the change in test fuel. EPA indicated we would defer action on 
appropriate adjustments, if any, for the GHG and CAFE programs until 
data were available to assess how the difference in the fuel properties 
(Tier 3 fuel compared to Tier 2 fuel) would impact the stringency of 
the CAFE and GHG standards for Tier 3 technology vehicles and the 
calculations for the fuel economy label. EPA indicated that any 
adjustments or changes in the regulatory text would be done through a 
future action.
    Manufacturers commented that EPA should take action on the 
necessary adjustments to compliance calculations as part of the Tier 3 
final rule. The methodologies for addressing some elements of the 
changes in fuel properties such as the difference in energy density are 
already addressed in the regulation. One key element, the ``R'' factor 
found in the equation of 40 CFR 600.113-12(h)(1) is intended to capture 
inefficiencies and differences in how vehicles respond to changes in 
the energy content of the fuel. This factor is empirically based, 
developed using vehicle test data. This value is presently set at 0.6 
and is shown in the denominator of the aforementioned equation. While 
there has been some data evaluated to assess the impact of changing the 
emission test fuel on the ``R'' factor, EPA did not propose a value in 
the NPRM and specifically stated that we would continue to investigate 
this issue and if necessary address it as part of a future action, as 
opposed to changing it in the Tier 3 final rule. Furthermore, as 
discussed above, there is a need for more data to fully understand how 
other changes in certification fuel for Tier 3, such as the octane 
specification, may affect the stringency of the CAFE and GHG standards 
which were based on Tier 2 emission fuel, as well as any implications 
for the fuel economy label. These potential effects are best understood 
using emission data generated on Tier 3/LEV III vehicles tested on both 
Tier 3 and Tier 2 test fuel.
    In addition, the manufacturers commented that even with the use of 
``analytically derived data'' as permitted under current EPA 
regulations and guidance, \419\ EPA should finalize an appropriate test 
procedure adjustment in the Tier 3 rulemaking, including adoption of an 
``R'' factor of 1.0, and should allow manufacturers the option of using 
Tier 2 fuel for CAFE, GHG, and fuel economy labeling at least through 
MY2019 to provide time for adjusting to the new test fuel.
---------------------------------------------------------------------------

    \419\ See 40 CFR 600.006-08(e) and EPA guidance letter CD 12-03, 
February 27, 2012 and CCD-04-06, March 11, 2004, available at http://iaspub.epa.gov/otaqpub/.
---------------------------------------------------------------------------

    In the NPRM, EPA indicated that we would not be changing the ``R'' 
factor or implementing other adjustments or changes in the regulatory 
text in the FRM. In follow-up meetings with the manufacturers, we 
expressed a willingness to consider permitting GHG and CAFE to continue 
on Tier 2 fuel until the future rulemaking action to address the ``R'' 
factor and other potential changes was complete and in effect. The 
manufacturers responded that under this approach the existing 
regulations would require a significant amount of additional emission 
testing for any model certified to the Tier 3/LEVIII exhaust emission 
standards before the future rulemaking is completed and in effect.\420\ 
This is because Tier 3 test fuels would be used in emission data 
vehicles (EDVs) evaluated for compliance with Tier 3 criteria pollutant 
standards, but these same EDVs would also have to be tested on Tier 2 
fuel for GHG, fuel economy label, and CAFE program data purposes. Also, 
while Tier 2 fuel would apply to EDVs and fuel economy data vehicles 
(FEDVs) evaluated for fuel economy label, CAFE program data values, and 
compliance with GHG standards, these same FEDVs would have to be 
retested on Tier 3 fuel to show compliance with the Tier 3 criteria 
pollutant standards. This additional testing would also extend to in-
use verification program (IUVP) testing under 40 CFR 86.1845 through 
86.1853.
---------------------------------------------------------------------------

    \420\ This could start as early as the 2015 MY when the LEV III 
program begins to phase-in.
---------------------------------------------------------------------------

    In response to the concerns expressed by the manufacturers, EPA has 
identified five interim changes to existing regulations to both clarify 
testing requirements and to provide the manufacturers a reasonable 
opportunity to continue to test for CAFE, GHG, and labeling purposes on 
Tier 2 test fuels for each EDV and FEDV until such time as EPA 
determines appropriate adjustments, if any, related to a change to Tier 
3 test fuels. EPA believes these changes can be implemented without 
impacting the integrity of the testing conducted for the criteria 
pollutant, CAFE, and GHG standards or values generated for 
determination of fuel economy labels. It is very important to

[[Page 23532]]

note that the emission test data generated by these early Tier 3/LEVIII 
vehicles covering both Tier 2 and Tier 3 test fuel will provide data 
needed to assess the ``R'' value and the impact of the fuel change on 
the stringency of the CAFE and GHG standards, and the calculations for 
the fuel economy labeling program. These data will be instrumental in 
developing any appropriate adjustments to maintain equivalent 
stringency for the CAFE and GHG standards and to update the fuel 
economy labeling calculations, as needed. At the present time, EPA 
expects to have the needed data in early to mid 2015 and will then be 
in a position to conduct a thorough assessment of the impacts of 
different emission test fuels on Tier 3/LEV III vehicles and develop 
any appropriate adjustments and changes, in consultation and 
coordination with NHTSA.
    These interim changes which are presented below and shown in Table 
IV-29, apply only to vehicles certified to the Tier 3 and/or LEV III 
exhaust emission standards in the model years before the future action 
mentioned above takes effect. These are reflected in 40 CFR 80.600.117.
    1. For any given EDV or FEDV, our regulations will require that 
testing related to CAFE and GHG standards and the fuel economy label 
must still be done on Tier 2 fuel even if criteria pollutant testing is 
done on Tier 3 or LEV III fuel. The ``R'' value used in the fuel 
economy equation would remain at 0.6 until any change is made in a 
future rulemaking.
    2. The requirement continues that FEDVs are expected to meet the 
criteria pollutant emission standards. As a flexibility, rather than 
requiring FEDVs to retest on Tier 3 fuel to show that they pass the 
criteria pollutant emission standards, we are providing in the 
regulations that FEDVs may meet these standards using Tier 2 fuel on 
each of the five cycles (as applicable) or be subject to retesting and 
passing on Tier 3 fuel if they do not meet requirements on Tier 2 fuel 
or otherwise do not comply with 40 CFR 86.1835-01(b) and 40 CFR 
600.008(b). In these circumstances, assuming a retested vehicle meets 
criteria pollutant standards on Tier 3 fuel, the emissions results on 
the Tier 2 fuel will still be used for CAFE, GHG, and fuel economy 
labeling purposes. Retesting on Tier 3 fuel is only required for those 
cycles where the FEDV did not meet the criteria pollutant standards on 
Tier 2 fuel.
    3. As a flexibility, if EDV testing is conducted on Tier 3/LEV III 
fuel for criteria pollutants (all 5 cycles), then we are requiring the 
EDV testing to be conducted on Tier 2 fuel for only 2 cycles (FTP and 
HFET) for GHG and CAFE purposes. These emission results on Tier 2 fuel 
are expected to meet the Tier 3 criteria pollutant standards. Our 
regulations then require manufacturers to use these EDV Tier 2 fuel 
test results (FTP and HFET) for the CAFE, and GHG standards. The EDV 
Tier 2 fuel test results (FTP and HFET) would also be used for fuel 
economy label calculations except in rare cases where the EDV does not 
pass the litmus test or if the manufacturer voluntarily elects to use 
the vehicle specific 5-cycle method to determine fuel economy label 
values. In those two cases, the EDV would need to be tested on Tier 2 
test fuel on each of the five cycles.
    4. As a flexibility, during the interim model years, manufacturers 
may use either Tier 2 or Tier 3/LEVIII test fuel emission results to 
conduct the litmus evaluations for fuel economy labeling under 40 CFR 
600.115-11. All emission results for the five tests involved used must 
be from the same test fuel. EPA believes this is appropriate since the 
litmus evaluation is based on a comparison of the percent differences 
of 2 and 5 cycle values rather than absolute differences in the values. 
If a manufacturer chooses to conduct the litmus evaluation using LEVIII 
fuel, the cold FTP test must still use Tier 3 fuel. In the situation 
where the manufacturer uses Tier 3/LEV III test fuel for the litmus 
test the R-factor will be 0.6. EPA will provide guidance on determining 
the values for the other fuel quality parameters needed for the fuel 
economy calculations when Tier 3/LEVIII fuel is used.
    5. Exhaust emission testing for IUVP for GHGs shall be conducted 
using the same test fuel as used for criteria pollutant certification, 
unless the manufacturer uniformly elects to conduct its IUVP GHG 
testing on Tier 2 fuel. This relieves the need to conduct IUVP testing 
for criteria pollutants on Tier 3 fuel and GHG testing on Tier 2 fuel. 
EPA believes this is an acceptable interim regulatory flexibility, 
since the IUVP testing for GHGs does not involve the IUCP provisions of 
40 CFR 86.1846-01.

                               Table IV-29--Interim Testing Requirements for EDVs and FEDVs on Tier 3 and Tier 2 Test Fuel
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                       Criteria      GHG/Label/CAFE  (EDVs and FEDVs)  (tier 2 fuel)    Litmus  calculation              IUVP
------------------------------------   pollutant  ------------------------------------------------------------------------------------------------------
           Tests/  cycles               (EDVs)        5-cycle          2-cycle  (CAFE/GHG/label)              5-cycle           Criteria        GHG*
--------------------------------------------------    (label)   -------------------------------------------------------------   pollutant  -------------
                                        5-cycle   --------------                                                             --------------
                                    --------------
                                      Tier 3 fuel                                                        Tier 2 or  Tier 3
      Test fuel  requirements          or other    Tier 2  fuel  Tier 2  fuel       Tier 3  fuel                fuel          Tier 3  fuel  Tier 2  fuel
                                      transition
                                       option**
--------------------------------------------------------------------------------------------------------------------------------------------------------
FTP................................            X             X             X   Show criteria           Use 5-cycle Tier 3               X             X
                                                                                pollutant standards     fuel or Tier 2 fuel
                                                                                are met using Tier 2    test results.
                                                                                fuel or must retest
                                                                                on Tier 3 fuel.
HFET...............................            X             X             X   ......................  .....................            X             X
US06...............................            X             X   ............  ......................  .....................            X
SC03...............................            X             X
Cold FTP...........................            X             X
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Manufacturer may uniformly elect to use Tier 2 fuel results to meet the IUVP GHG requirements or rely on Tier 3 results.
** California Phase 2 fuel is only permitted for GHG/Label/CAFE and Litmus assessments for vehicles certified for criteria pollutants in the Tier 3
  program using carryover data from CARB LEV II certifications such as SULEVs and PZEVs.


[[Page 23533]]

    Manufacturers may use LEVIII fuel (California Phase 3) in lieu of 
Tier 3 fuel, but any cold FTP testing must be done using Tier 3 Cold 
FTP fuel. LEV III fuel is 7 RVP E10, Tier 3 fuel is 9 RVP E10, and Tier 
2 fuel is 9 RVP E0.
    Manufacturers have presented two points of view with regard to when 
the potential new requirements (including a revised ``R'' factor and 
other possible test procedure changes/adjustments related to CAFE, GHG, 
and fuel economy labeling) should take effect once the future 
rulemaking action mentioned above is complete. Some have stated that 
use of the new provisions should be available for use as soon as 
possible after the rule is completed. This would minimize the need for 
any future duplicate testing and put manufacturers on course for fully 
aligning with the new requirements quickly. Others have asked that 
there be lead time provided before the application of the new 
requirements becomes mandatory. The manufacturers have expressed 
concern that the use of the new requirements more quickly by one 
manufacturer versus another could create a competitive imbalance. At 
the same time, manufacturers do not necessarily want to be forced to 
certify all products to the new requirements by a cut-off date (e.g., 
2020 model year) without EPA consideration of phase-in or phase-out 
provisions and data carryover.
    EPA understands the manufacturers' various issues and concerns in 
this area. Based on the information available at this time, EPA is 
expecting to allow the optional use of any future adjustments for 
compliance calculation and labeling purposes as soon as the future rule 
mentioned above becomes effective. Furthermore, we expect that the 
mandatory use of any such new adjustments with all Tier 3 
certifications would be required for the 2020 MY. These initial timing 
projections are subject to revision based on timing of the completion 
of the future action and the data and record developed in that future 
rulemaking.
b. Useful Life for GHG Standards
    As stated above, EPA is committed to retaining equivalent 
stringency for GHG emissions compliance beginning in MY 2017. We need 
more emissions test data to better understand the GHG emission impacts 
of Tier 3 fuel in Tier 3 technology vehicles. However, we believe that 
certifying a vehicle to a longer useful life for any emission 
constituent would have only a beneficial effect on emissions. To 
address potential concerns about changes in the stringency of the GHG 
standards resulting from a longer useful life, we are not requiring a 
longer useful life for GHG emission standards, although manufacturers 
can optionally certify GHG emissions to a 150,000 mile, 15 year useful 
life.
6. Consideration of Test Fuel for Nonroad Engines and Highway 
Motorcycles
    As described earlier in Section IV.F., we are adopting new 
specifications for the gasoline emissions test fuel used for testing 
highway vehicles subject to the Tier 3 standards. Earlier in the 
development of this rulemaking, EPA also considered changing the test 
fuel specifications for other categories of engines, vehicles, 
equipment, and fuel system components that use gasoline. These include 
a wide range of applications, including small nonroad engines used in 
lawn and garden applications, recreational vehicles such as ATVs and 
snowmobiles, recreational marine applications, and highway motorcycles. 
While engines in some of these categories employ advanced technologies 
similar to light-duty vehicles and trucks, the vast majority of these 
engines employ much simpler designs, with many of the engines being 
carbureted with no electronic controls. Because of the lower level of 
technology, emissions from these engines are potentially much more 
sensitive to changes in fuel quality.
    EPA is not applying the new emissions test fuel specifications to 
these other categories of engines, vehicles, equipment, and fuel system 
components. In discussing the potential change in test fuel 
specifications with the large number of businesses potentially impacted 
by such a change, many companies supported such a change. However, a 
number of manufacturers raised concerns about the level of ethanol in 
the new fuel, the cost of recertifying emission families on the new 
fuel, the impact on nationwide product offerings, and the cost impact 
of complying with the existing standards on the new test fuel. EPA 
believes it is important that the test fuel for these other categories 
reflect real-world fuel qualities but has elected to defer moving 
forward now pending additional analysis of the impacts of changing the 
test fuel specifications for the wide range of engines, vehicles, 
equipment and fuel system components that could be impacted. These 
impacts include the impact on the emissions standards, as well as the 
other issues raised by the manufacturers. EPA plans to explore such a 
change in a separate future action.
    While we are not changing the test fuel specifications for these 
other types of vehicles and engines, we are updating the reference 
standards associated with specific parameters and making minor 
adjustments to calculation methods. For certified engines and vehicles 
that have already been using the test fuel specified in Sec.  1065.710, 
we are clarifying that the RVP is calculated using the same equation 
described above for the new fuel specified for Tier 3 vehicles. We are 
also taking the opportunity to align and update test methods for the 
various gasoline test fuels in 40 CFR part 86. Specifically, we are 
revising Sec. Sec.  86.113 and 86.213 to (1) use both ASTM D2699 and 
ASTM D2700 for octane measurements involving both research and motor 
octane specifications (including octane sensitivity), (2) use ASTM 
D2622 for all sulfur measurements, which is widely used and provides 
superior results compared with the methods that have been referenced in 
the regulations, (3) use ASTM D5191 for measuring fuel volatility, 
including the calculation described above. We are also updating the 
regulations to reference a newer version of the following currently 
referenced procedures: ASTM D86, ASTM D1319 ASTM D2699, ASTM D3231, and 
ASTM D3237. All these changes and updates align with fuel 
specifications in 40 CFR part 1065.
7. CNG and LPG Emissions Test Fuel Specifications
    There are currently no sulfur specifications for the test fuel used 
for certifying natural gas (CNG) vehicles. There is also no sulfur 
specification in 86.113 for the test fuel used for certifying liquefied 
petroleum gas (LPG) light duty vehicles. The LPG certification test 
fuel for heavy-duty highway engines and for nonroad engines in 1065.720 
includes an 80 ppm maximum sulfur specification. We requested comment 
on the appropriateness of changing 86.113 to reference 40 CFR part 1065 
for all natural gas and LPG test fuels. We further requested comment on 
amending these specifications to better reflect in-use fuel 
characteristics, and in particular on the appropriateness of aligning 
the sulfur specifications with those that apply for gasoline test fuel. 
We noted that changing the sulfur specifications would depend on 
establishing that the new specification is consistent with the range of 
properties expected from in-use fuels.
    The Alliance of Automobile Manufacturers (the Alliance) stated that 
EPA should adopt a 10 ppm maximum sulfur specification for CNG and LPG

[[Page 23534]]

vehicle certification test fuels. They also stated that Sec.  86.113 
should reference part 1065 for CNG and LPG test fuels (for light and 
heavy duty vehicles). The American Petroleum Institute (API), the 
Association of Fuel and Petrochemical Manufacturers (AFPM), and several 
individual refiners stated that EPA should not establish new sulfur 
standards for CNG and LPG vehicle certification test fuels until 
additional data are available on the sulfur content of in-use CNG/LPG 
fuels. The National Propane Gas Association (NPGA) stated that they are 
opposed to a change in the sulfur specifications for LPG vehicle 
certification test fuels given that they are unaware of any issue that 
would warrant such a change.
    As discussed in Section V.J. of today's preamble, additional time 
is needed for EPA to work with industry to collect data on current CNG/
LPG sulfur content, to determine whether additional control of in-use 
CNG/LPG sulfur content is needed, and to evaluate the feasibility and 
costs associated with potential additional sulfur controls. Therefore, 
we are deferring finalizing in-use quality and certification test fuel 
specifications for CNG and LPG at this time.

G. Small Business Provisions

    We are adopting special flexibility provisions for small businesses 
that are subject to the Tier 3 emissions standards. Such businesses are 
typically vehicle manufacturers, independent commercial importers 
(ICIs), or alternative fuel vehicle converters. We are also providing 
Tier 3 flexibility to companies that, though they may not meet the 
eligibility requirements for small businesses, sell less than 5,000 
vehicles per year in the United States, and thus qualify as small 
volume manufacturers (SVMs). These companies and small businesses 
typically face similar challenges in implementing new EPA vehicle 
standards.
    As in previous vehicle emissions rulemakings in which we have 
provided such flexibilities, our reason for doing so is that these 
entities generally have more implementation difficulty than larger 
companies. Small companies generally have more limited resources to 
carry out necessary research and development; they can be a lower 
priority for emission control technology suppliers than larger 
companies; they have lower vehicle production volumes over which to 
spread compliance costs; and they have a limited diversity of product 
lines, which limits their ability to take advantage of the phase-in and 
averaging provisions that are major elements of the Tier 3 program.
    We proposed small business provisions largely based on the 
recommendations of the Small Business Advocacy Review (SBAR) Panel, 
described in Section XIII.C of the Notice of Proposed Rulemaking 
(NPRM). We proposed provisions for additional lead time, reduced 
testing requirements, and opportunities for hardship relief to help 
small entities to leverage technological developments by others and to 
spread the availability of needed engineering, supplier, and capital 
resources. Based on the comments we received, we have improved on the 
proposed provisions in the final rule as described in detail below.
1. Lead Time and Relaxed Interim Standards
    We proposed that small businesses and SVMs be allowed to postpone 
compliance with the standards and other Tier 3 requirements, including 
use of the new certification test fuel, until model year (MY) 2022. For 
MY 2022 and later, they would be subject to the same Tier 3 
requirements as other manufacturers, including the declining fleet 
average NMOG+NOX standards and the fully phased in 30 mg/mi 
FTP standard for MYs 2025 and later. We requested comment on adopting 
relaxed FTP NMOG+NOX standards for small companies in the 
light-duty market segment, noting that LEV III provides light-duty SVMs 
with relaxed FTP NMOG+NOX standards of 125 and 70 mg/mi in 
MYs 2022 and 2025, respectively.
    We did not receive comments from non-SVM small businesses subject 
to the Tier 3 vehicle standards about our proposed small entity phase-
in provisions. However, we received comments from SVMs, as well as the 
Alliance of Automobile Manufacturers and the Association of Global 
Automakers, arguing that the proposed phase-in did not provide adequate 
lead time relief for SVMs, and that the long-term Tier 3 standards for 
light-duty vehicles are not technologically feasible for SVMs. They 
highlighted the ability of large manufacturers to offset high emissions 
from high-performance, luxury models by averaging with their low-
emitting models, while competing SVM products must be designed to 
actually achieve low emissions while still meeting customers' 
performance expectations. Their limited production can also result in 
emission control technology suppliers placing a lower priority on SVM 
orders than on those of larger, high-volume manufacturers.
    Because of these factors, SVMs suggested that their companies meet 
a slightly more stringent NMOG+NOX standard (125 mg/mi) than 
what we proposed for SVMs in the early years of the program, and a 
permanently relaxed standard of 51 mg/mi beginning in MY 2022. Ferrari 
suggested a compliance schedule for SVMs similar to the California LEV 
III program, with either a permanently relaxed standard (matching the 
California LEV III 70 mg/mi long-term standard) or a delay until MY 
2030 to meet the primary 30 mg/mi Tier 3 standard (when they suggest 
that SVMs could potentially comply). CARB comments supported Tier 3 
adoption of its LEV III provisions for SVMs, including the long-term 70 
mg/mi standard beginning in MY 2025. VNG, a natural gas fuel network 
provider, commented that gaseous-fuel small-volume test groups should 
be given extended phase-in opportunities identical to those proposed 
for SVMs, regardless of company size. As justification, VNG pointed to 
challenges unique to converting vehicles to operate on natural gas: 
thermal management of direct injection fueling and engine oil systems, 
adaptation of gasoline direct injection (GDI) controls to natural gas 
port fuel injection, and improvement of turbocharger response times.
    After considering the comments, we agree with SVMs that their 
unique logistical and technological challenges, especially in the later 
years of the primary FTP NMOG+NOX standards phase-in 
schedule, warrant a significant period of relaxed standards for these 
manufacturers. However, we have found no fundamental reason why, given 
sufficient lead time, all manufacturers, regardless of company size and 
vehicle characteristics, will not be able to meet the Tier 3 standards. 
Thus, we are finalizing an optional program for SVMs, available to non-
SVM small businesses as well, under which they can choose an 
alternative 3-stage FTP NMOG+NOX fleet average standard 
phase-in schedule: an initial standard of 125 mg/mi for MYs 2017 
through 2021, a more stringent standard of 51 mg/mi for MYs 2022 
through 2027, and the final Tier 3 standard of 30 mg/mi thereafter.
    Because companies choosing this 3-stage compliance option are 
certifying to Tier 3 bin standards in MY 2017, we are requiring that 
other exhaust emissions standards, including SFTP and PM standards, 
apply for their vehicles as well, to the same degree and on the same 
schedule as for other manufacturers. Application of evaporative 
emissions and onboard diagnostics (OBD) standards, on the

[[Page 23535]]

other hand, is not affected by choice of the 3-stage compliance option 
for the FTP NMOG+NOX standards, and small companies may 
separately choose to delay compliance with evaporative emissions and 
OBD standards (except as noted in Section IV.G.3) until MY 2022, as 
proposed. In addition, small companies choosing the 3-stage compliance 
option may delay the longer useful life and new test fuel requirements 
for exhaust emissions standards until MY 2022 to align these changes 
with the 3-stage schedule. This option would not preclude use of other 
applicable small entity flexibility provisions discussed in this 
subsection.
    Although we are adopting this revised implementation schedule for 
SVMs and small businesses, we believe the proposed approach of allowing 
postponement of Tier 3 compliance until MY 2022 may be useful for small 
companies needing more lead time to begin certifying Tier 3 vehicles. 
Therefore we are finalizing the proposed approach as an additional but 
separate option for such companies, including SVMs, ICIs, and 
alternative fuel vehicle converters. Furthermore, because the optional 
3-stage SVM implementation schedule, and the record of comments that 
prompted it, are specific to the light-duty sector, we are not 
extending it to heavy-duty vehicles and instead are finalizing only the 
proposed approach of allowing postponement of Tier 3 compliance until 
MY 2022 for any SVMs and small businesses in the heavy-duty sector.
    Companies that take advantage of one of the SVM and small business 
implementation schedule provisions in either the light-duty or heavy-
duty sector are not allowed to generate or use Tier 3 exhaust emissions 
credits in that sector while or before they are subject to 
significantly less stringent standards than other manufacturers. That 
is, they cannot earn or use Tier 3 exhaust emissions credits before MY 
2022 under the 3-stage light-duty SVM revised implementation schedule, 
and they also cannot do so before MY 2022 if they are using the 
postponed compliance schedule that we proposed, unless they choose to 
end their use of these SVM implementation options earlier than MY 2022.
    We disagree with VNG's assessment that small-volume test groups of 
large manufacturers should have until 2022 to comply with Tier 3. The 
technical challenges outlined by VNG have to do with converting 
gasoline vehicles to run reliably and durably on natural gas. Although 
these conversion challenges may be exacerbated for the new generation 
of turbocharged GDI vehicles, we have no evidence or comments from a 
vehicle manufacturer indicating that meeting Tier 3 standards is 
significantly more difficult for natural gas vehicles than for gasoline 
vehicles. Note that we are providing some relief for small volume test 
groups in the form of assigned deterioration factors (discussed below), 
but not because of feasibility concerns. Rather, we believe that 
assigned deterioration factors provide a sufficient alternative to the 
extensive process of developing a unique factor for each low-volume 
vehicle model. We find no justification to delay compliance with Tier 3 
standards for larger manufacturers' low-volume models as requested by 
VNG.
2. Assigned Deterioration Factors
    In Tier 3 as in past programs, manufacturers must demonstrate 
compliance with emissions standards throughout the vehicle's useful 
life. This is generally done by testing vehicles at low mileage and 
then applying a deterioration factor to the measured emissions levels. 
The deterioration factors are determined by testing emissions control 
systems before and after an aging process. In the past we have allowed 
small entities to use deterioration factors assigned by EPA instead of 
performing the extended testing, and we proposed to do so again for 
demonstrating compliance with Tier 3 exhaust and evaporative emissions 
standards. We did not propose specific assigned deterioration factors, 
but noted that the proposed delay in the small entity compliance 
schedule to MY 2022 would allow sufficient deterioration data from 
large manufacturers to accumulate for timely development of these 
factors.
    We are adopting the assigned deterioration factor provisions for 
small businesses and SVMs (as well as for small volume test groups), as 
proposed. Commenters expressed support, and asked that the Agency 
commit itself to keeping these factors up to date as durability data 
accumulates. In response, we can state that we are committed to 
periodically updating and publishing these assigned deterioration 
factors. Given that SVMs will be allowed to use the revised 
implementation schedule described above, starting in MY 2017, it 
becomes necessary to consider assigned deterioration factors in stages. 
Because there may not be a sufficient base of accumulated durability 
data on Tier 3 vehicles by MY 2017, we expect that the current set of 
assigned factors based on Tier 2 vehicles may continue in place for 
some time, noting that the MY 2017-2021 SVM fleet average of 125 mg/mi 
is not too much different from the average of today's Tier 2 vehicle 
emissions. By MY 2022, when the SVM NMOG+NOX fleet average 
standard drops to 51 mg/mile, we expect to have new assigned factors 
available. We note that small businesses and SVMs may also, with 
advance EPA approval, use deterioration factors developed by another 
manufacturer (40 CFR 86.1826-01(b)).
3. Reduced Testing Burden and OBD Requirements
    Under our existing regulations, manufacturers must perform in-use 
testing on their vehicles and demonstrate that their in-use vehicles 
comply with the emissions standards. These regulations provide for 
reduced levels of testing for small companies with annual sales under 
15,000, and for no in-use testing for those with annual sales up to 
5,000. We received no adverse comments on our proposal to continue this 
approach in Tier 3, and are retaining it.
    As described in Sections IV.A and IV.B, we are requiring 
manufacturers to test for PM emissions from vehicles of all fuel types, 
a change from previous practice in which non-diesel vehicles could be 
waived from PM testing. However, we proposed and have decided to 
continue the PM testing waiver in Tier 3 for small businesses and SVMs. 
In lieu of testing, these companies are required to make a statement of 
compliance with the Tier 3 PM standards, and their vehicles are still 
subject to the standards. We may however measure PM emissions to 
determine compliance in EPA confirmatory or in-use testing.
    We proposed to apply CARB's OBD requirements to Tier 3 vehicles, 
except that small alternative fuel vehicle converters would be allowed 
to instead meet our existing OBD requirements (40 CFR 86.1806-05). The 
natural gas fuel network provider VNG objected that the proposed 
exception disadvantages larger vehicle manufacturers and should be made 
equally available to all vehicle manufacturers' small volume test 
groups. We expect that larger manufacturers wishing to produce 
alternative fuel vehicles will be familiar with CARB's OBD requirements 
and well-positioned to implement these requirements in Tier 3. We note 
that larger OEMs themselves did not request to be covered by an 
extension of this provision.
    We are finalizing the exception to the Tier 3 OBD requirements as 
proposed. Note that the optional delay in Tier 3 implementation until 
MY 2022 that is available to small businesses, discussed

[[Page 23536]]

above, includes a delay in the Tier 3 OBD requirement to MY 2022, as 
proposed, except that vehicles already meeting this requirement in MY 
2017 must continue to do so in subsequent years. We are also adopting 
this Tier 3 OBD delay to MY 2022 for small companies taking advantage 
of the revised light-duty 3-stage implementation schedule discussed 
above, even though other Tier 3 requirements start for them in MY 2017, 
in order to avoid overburdening these manufacturers with multiple sets 
of new OBD design constraints.
4. Hardship Relief
    We proposed and are adopting provisions for small businesses and 
SVMs in hardship situations to apply for additional time to meet the 
Tier 3 standards. Such appeals will need to include evidence that the 
noncompliance would occur despite the manufacturer's best efforts to 
comply, and that severe economic hardship would occur if the relief is 
not granted, though the company need not show that its solvency will be 
in jeopardy without the relief. (This showing is required in other EPA 
programs granting hardship relief under 40 CFR 1068.250.) The duration 
of relief will be established on a case-by-case basis for Tier 3 and is 
not being limited by regulation. Commenters supported these proposed 
provisions, within the context of a revised approach to SVM lead time, 
discussed above.
5. Eligibility for the Flexibilities
    As proposed, we are using the federal Small Business Administration 
(SBA) criteria to define small businesses eligible for the special 
provisions. SBA defines small business vehicle manufacturers as those 
with less than 1,000 employees, and small business ICIs and alternative 
fuel vehicle converters are evaluated using SBA criteria based on 
annual revenues. See Section IV.H.3 for a discussion of additional 
provisions that apply specifically to ICIs. Also, as proposed, we are 
defining SVMs in 40 CFR 86.1838-01 for purposes of Tier 3 as companies 
with nationwide annual U.S. sales volumes at or below 5,000 vehicles, 
though the 15,000 vehicle threshold used in Tier 2 continues to apply 
in a few regulatory provisions that Tier 3 changes are not impacting. 
Eligibility will be evaluated using an average of 2012-2014 MY sales. 
For companies with no 2012 MY sales, projected sales may be used, but 
their eligibility will be re-evaluated thereafter using a three-year 
running average.
    VNG commented that the proposed 5,000 vehicle threshold could 
potentially limit the ability (or willingness) of natural gas SVMs to 
scale up production by forcing a tradeoff between sales and regulatory 
burden, pointing also to the fact that 15,000 vehicles is only 0.1% of 
annual light-duty vehicle sales. We do not believe that the SVM relief 
provisions are so advantageous as to cause self-limiting of sales, 
except possibly in the unlikely case of a company very near the 
threshold. Even if this were to happen, moving the threshold to 15,000 
would not prevent the same dynamic from happening at that sales level. 
Furthermore, our use of a three-year average of sales for determining 
SVM eligibility protects the SVMs from being penalized for having an 
especially good year not reflective of its long-term growth trend. See 
the MY 2017 and later light-duty GHG final rule for a discussion of our 
basis for adopting the 5,000 vehicle threshold (77 FR 62793, October 
15, 2012).
    We requested comment on extending eligibility for the Tier 3 SVM 
provisions to small manufacturers that are owned by large manufacturers 
but are able to demonstrate that they are operationally independent. We 
established such a provision in the light-duty greenhouse gas (GHG) 
program, and CARB did so in LEV III. Comments from CARB and Ferrari 
supported this extension. No commenters opposed it; however, Advanced 
Biofuels USA recommended caution to avoid advantaging SVMs capable of 
leveraging parent company resources to drastically increase U.S. market 
share within 2-3 years. Given the establishment of this provision in 
our GHG program, and the value of this extension for harmonization with 
LEV III, we are adopting this change into Tier 3 using the same 
eligibility criteria as in our GHG program, set forth in 40 CFR 
86.1838-01(d). We believe these criteria are sufficiently strict and 
objective to address the concerns expressed by Advanced Biofuels USA.
    To qualify as SVMs in either the light-duty or heavy-duty Tier 3 
programs, the company's total sales of vehicles subject to standards 
under 40 CFR part 86, subpart S count toward the vehicle sales limit, 
including both light- and heavy-duty vehicles. Companies so qualified 
may take advantage of SVM provisions in both sectors.

H. Compliance Provisions

1. Exhaust Emission Test Procedures
    We are finalizing most of the amendments we proposed to 40 CFR part 
1066 as part of the effort to migrate test requirements from 40 CFR 
part 86. We began this process a couple of years ago when we 
established part 1066, but we applied these test procedures only to 
certain vehicles above 14,000 lbs gross vehicle weight rating (GVWR) 
for the purpose of measuring greenhouse gas emissions (76 FR 57470, 
September 15, 2011). This final rule extends these procedures, with 
some amendments, to vehicles at or below 14,000 lbs GVWR for 
measurement of both criteria pollutants and greenhouse gas emissions. 
The procedures in part 1066 cover the same requirements that have been 
included in 40 CFR part 86, but include more detailed specifications 
for how to measure exhaust emissions using a chassis dynamometer. They 
also reference large portions of 40 CFR part 1065 to align test 
specifications that apply equally to engine-based and vehicle-based 
testing, such as CVS and analyzer specifications, calibrations, test 
fuels, calculations, and definitions of many terms. Overall, the part 
1066 procedures represent a modernization of the part 86 procedures 
rather than fundamentally different procedures.
    Until this rule, testing requirements related to chassis 
dynamometers have relied on a combination of regulatory provisions, EPA 
guidance documents, and extensive learning from industry experience 
that has led to a good understanding of best practices for operating a 
vehicle in the laboratory to measure emissions. The revisions we are 
finalizing capture this range of material, integrating and organizing 
these specifications and procedures to include a complete set of 
provisions to ensure that emission measurements are accurate and 
repeatable.
    This final rule includes the following revisions to part 1066:
     Clarification of regulatory requirements.
     Migration of mass-based emission calculations from part 86 
to part 1066.
     Introduction of a new NMOG calculation.
     Revision of 40 CFR part 1066, subpart B, to increase the 
specificity with which part 1065 references are made as they pertain to 
testing equipment, test fluids, test gases, and calibration standards.
     Addition of coastdown procedures for light-duty vehicles.
     Reordering of the test sequence with respect to vehicle 
preparation and running a test.
     Specifying part 1065 procedures for PM measurement, 
including certain deviations from part 1065 for chassis testing.

[[Page 23537]]

     Insertion of detailed test specifications for vehicles 
certified under 40 CFR part 86, subpart S.
     Addition of provisions related to testing with four-wheel 
drive dynamometers, as described below.
     Correction of typographical errors.
    We are finalizing the use of part 1065 for PM measurement with 
slight adjustments to the dilution air temperature, minimum dilution 
ratio, and background measurement requirements. By controlling the 
parameters that affect PM formation (dilution air temperature, dilution 
factor, sample residence time, filter face temperature, and filter face 
velocity), the procedures will reduce lab-to-lab and test-to-test 
variability.
    The regulations being finalized will provide alternative approaches 
to sample PM onto different combinations of filters. One option is to 
collect a sample for phases 1 and 2 of the FTP on a single filter, and 
collect a sample for phases 2 and 3 of the FTP onto a second filter. 
Another option is to collect a sample for phases 1, 2, and 3 on a 
single filter. A final option is to sample PM emissions from two full 
UDDS cycles; however manufacturers choosing this option must still run 
a separate three-bag test for evaporative emission testing. We will 
continue to allow sampling under the traditional FTP methodology of a 
bag or filter per test phase (3 phases in total) instead of these new 
methods. We are also finalizing new PM sampling and calculation methods 
as proposed.
    We are revising the chassis dynamometer specifications in part 1066 
by removing the maximum roll diameter and by requiring speed and force 
measurements at a minimum frequency of 10 hertz (Hz). Some 
manufacturers may be interested in testing with nonstandard dynamometer 
configurations, such as new flat-track dynamometers or old twin-roll 
dynamometers. We may approve the use of these and other nonstandard 
dynamometer configurations as alternative procedures under 40 CFR 
1065.10(c)(7).
    We proposed that EPA may test vehicles with the capability of all-
wheel drive operation with dynamometers operating in either two-wheel 
drive or four-wheel drive mode, regardless of the type of dynamometer 
that the manufacturer used for certifying the vehicle. However, the 
final regulations specify that we will conduct our testing using the 
same drive mode as the manufacturer. Vehicle manufacturers commented 
that differences in test results between a vehicle tested on a two-
wheel drive and a four-wheel drive dynamometer might be due to 
differences in dynamometer characteristics more than in vehicle 
operation. Results of a government-industry study that tested vehicles 
on both two-wheel and four-wheel drive dynamometers indicated fuel 
economy differences in the range of 4%, although the study 
was inconclusive with respect to the cause of the differences.\421\ 
Based on the results of this study, we will continue to test vehicles 
during confirmatory tests using the manufacturer's dynamometer 
configuration for that vehicle, and that test will be the official 
certification result. We are, however, finalizing revisions to 40 CFR 
1066.410(g) to clarify that we may also test the manufacturer's vehicle 
in a different dynamometer configuration than what was used for 
certification testing for information-gathering purposes. If we decide 
to perform this testing, we will depend on the manufacturer to 
cooperate in reconfiguring the test vehicle for our testing. We will 
continue to investigate the effects of four-wheel drive dynamometers on 
emission results and will not rule out possible future test procedure 
changes that might require certification of, or allow EPA to perform 
confirmatory testing on, any vehicle on a four-wheel drive dynamometer.
---------------------------------------------------------------------------

    \421\ ``Four Wheel Drive Dynamometer Meeting with the Alliance 
of Automobile Manufacturers and the Global Automakers,'' EPA Memo 
from Chris Laroo, November 13, 2013.
---------------------------------------------------------------------------

    In their comments to this rulemaking, vehicle manufacturers 
stressed the importance to them that EPA use the same test procedures 
that they used for their certification testing when we perform 
confirmatory testing on their vehicles. Although the manufacturers did 
not explain the reasons for their comment, we presume that the 
manufacturers' concern relates to situations where EPA test procedures 
would lead to higher emission levels than those resulting from a 
slightly different test procedure used by a manufacturer. If so, the 
concern is misplaced. The purpose of EPA's test procedure flexibility 
provisions is not to allow manufacturers to use test procedures as a 
tool to enable compliance with the standards--in other words, to 
demonstrate compliance for engines that in the absence of the 
regulatory test procedure flexibility would not meet the standard. 
Rather, the purpose is to reduce the burden of testing. We go through 
the rulemaking process to establish the specified default test 
procedures as a means of creating an objective measure of compliance 
with emission standards. Where we also include alternative procedures, 
they generally are not intended to change the conclusions from the 
rulemaking related to the stringency of the emission standards, or to 
lead to a different conclusion regarding compliance relative to the 
specified test procedures. EPA has addressed this issue previously for 
engine testing in Sec.  1065.10(a), where we note that we condition the 
allowance to use alternate procedures on the provision that they would 
``not affect your ability to show that your engines comply with the 
applicable emission standards.'' We note further that this provision 
``generally requires emission levels to be far enough below the 
applicable emission standards so that any errors caused by greater 
imprecision or inaccuracy do not affect your ability to state 
unconditionally that the engines meet all applicable emission 
standards.''
    In a related context, Sec.  1065.10(c)(1) explains that the intent 
of the test procedures is ``to produce emission measurements equivalent 
to those that would result from measuring emissions during in-use 
operation''. This provision, which also applies for vehicle testing, 
envisions a process in which both the manufacturer and EPA can apply 
their engineering judgment to improve the representativeness of the 
testing. It would be appropriate for a manufacturer to ask EPA to 
modify our test procedures if the manufacturer believed EPA's test 
procedures would lead to results that were unrepresentative of in-use 
operation. However, it would not be appropriate to ask us to modify our 
test procedures to make them less representative of in-use operation.
    The proposed rule included discussion of SI units as part of 
emission measurement procedures. At this time we are not converting 
emission standards to SI units. Note however that like part 86, part 
1066 relies extensively on calculations involving physical parameters 
to calculate emission rates and perform various calibrations and 
verifications. As already reflected in part 1066, manufacturers have 
used a variety of units to perform these calculations. We would expect 
that dynamometers and other laboratory equipment are all capable of 
operating in SI units even if current practice in some laboratories is 
to use other units. Moving toward standardized units for calculations 
will allow us to more carefully and appropriately specify precision 
values for various measured and calculated parameters. This will also 
simplify calculations, facilitate review of results from different 
laboratories, and help with communications regarding any round robin 
testing that might occur.

[[Page 23538]]

    As proposed, we will phase in the part 1066 test procedures for 
certifying all sizes of chassis-tested vehicles. All aspects of part 
1066 related to PM testing must be met at the start of MY 2017 for 
vehicles certified to the PM standards. All other aspects of part 1066 
must be met starting with the certification of MY 2022 vehicles. 
Manufacturers may begin using the part 1066 procedures before these 
deadlines, including step-wise changes to migrate gradually to part 
1066 procedures. The regulations will require that good engineering 
judgment be used during this transition to ensure that the effective 
stringency of the standards is not changed. We recognize that 
individual differences between part 86 and part 1066 test procedures 
may have a slight upward or downward impact on measured emissions, even 
though the combined overall impact will be negligible. Thus, during the 
migration, care must be taken to avoid applying an unbalanced mix of 
changes that could bias emissions.
    As described in Section IV.D, we are finalizing new test fuel 
specifications for E10 gasoline test fuel in 40 CFR part 1065. The test 
fuels specified for natural gas and liquefied petroleum gas, while not 
used for very many engine families, are currently following different 
specifications under 40 CFR part 86 and part 1065. We intend to revisit 
these fuel specifications in the future in the hope of adopting single, 
comprehensive fuel specifications for natural gas and liquefied 
petroleum gas that properly represent in-use fuels for highway and 
nonroad applications.
    The proposal also included various technical amendments to 40 CFR 
part 1065, which we are finalizing largely as proposed. See the Summary 
and Analysis of Comments for a discussion of changes we have made in 
response to comments. Of particular note is the revision to subpart F 
specific to preconditioning engines with exhaust aftertreatment 
devices. We are also adopting test procedures for unregulated 
pollutants such as semi-volatile compounds (PAHs, etc.). These 
technical amendments, which have no effect on the stringency of any 
emission standards, include several minor changes to clarify regulatory 
requirements, align with chassis-testing procedures where appropriate, 
and correct typographical errors.
2. Reduced Test Burden
    We are updating the regulatory provisions that allow manufacturers 
to omit testing for certification, in-use testing, and selective 
enforcement audits in certain circumstances. Sections IV.A.3, IV.B.6, 
and IV.G.3 describe how this applies for demonstrating that vehicles 
meet the Tier 3 PM standards. We are also allowing manufacturers to 
omit PM measurements for fuel economy and GHG emissions testing that 
goes beyond the testing needed for certifying vehicles to the Tier 3 
standards. Requiring such measurement would add a significant burden 
with very limited additional assurance that vehicles adequately control 
PM. We are also allowing manufacturers to ask us to omit PM and 
formaldehyde measurement for selective enforcement audits. If there is 
a concern that any type of vehicle would not meet the Tier 3 PM or 
formaldehyde standards, we will not approve a manufacturer's request to 
omit measurement of these emissions during a selective enforcement 
audit.
    The existing regulations have allowed for waived formaldehyde 
testing for gasoline- and diesel-fueled vehicles. The Tier 3 
NMOG+NOX emission standards are stringent enough that it is 
unlikely that vehicles will comply with the NMOG+NOX 
standards while exceeding the formaldehyde standards. We are therefore 
continuing this waiver practice, such that manufacturers of Tier 3 
vehicles do not need to submit formaldehyde data for certification.
3. Miscellaneous Provisions
    The following additional certification and compliance provisions 
are included in the final rule:
     The certification practice for assigned deterioration 
factors that are available for both small volume manufacturers and 
small volume test groups has matured significantly since it was first 
adopted. We are revising Sec.  86.1826 to more carefully reflect the 
current practice. For example, the existing regulations specified that 
manufacturers with sales volumes between 300 and 15,000 units per year 
should propose their own deterioration factors based on engineering 
analysis of emission data from other families. We believe it is best 
for EPA to develop a set of assigned deterioration factors that can 
apply to all small volume manufacturers and small volume test groups. 
The revised regulation accordingly spells out a process for EPA to use 
available information to establish assigned deterioration factors that 
can be used for any number of manufacturers and test groups.
     The regulations in 40 CFR part 86 rely on rounding 
procedures specified in ASTM E29. This standard is revised 
periodically. The newer versions are not likely to change in a way that 
affects the regulation, but the updates make it difficult to maintain a 
coordinated reference to the current protocol. We are addressing this 
by specifying that the rounding protocol described in 40 CFR 1065.20(e) 
applies, unless specified otherwise. We are not changing all the 
references in part 86; rather, we are defining ``round'' in subparts A 
and S to have the meaning given in 40 CFR part 1065 so that all new 
regulatory text would rely on this new description. The rounding 
specifications in 40 CFR part 1065 are intended to be identical to 
those in the latest versions of ASTM E29 and NIST SP811. For example, 
this now includes procedures for nonstandard rounding, such as rounding 
to the nearest 25 units, or the nearest 0.05, where that is 
appropriate.
     Independent Commercial Importers (ICIs) are companies that 
import specialized vehicles into the U.S. and are subject to EPA 
requirements specified in 40 CFR part 85, subpart P. The standards that 
apply to the imported vehicles depend in part on the vehicle's model 
year. Therefore, vehicles imported by ICIs in the future will 
eventually be subject to the Tier 3 standards. Because all existing 
ICIs are small businesses, the Tier 3 standards generally do not apply 
until 2022 at the earliest. In addition, the certification practices 
for ICIs have matured significantly since they were first adopted. EPA 
is adopting two changes to update how the regulations affect ICIs. 
First, we are adopting a requirement for ICIs to use electric 
dynamometers when running exhaust emission tests. Electric dynamometers 
have been required for many years for vehicle manufacturers, and EPA 
believes it is time to require that ICIs use such test equipment. In 
cases where an ICI can demonstrate that they will incur a substantial 
increase in compliance costs, the regulations include a provision 
allowing EPA to approve requests on a case-by-case basis to allow 
testing on other types of dynamometers until the ICI is able to use an 
electric dynamometer meeting current specifications. Second, we are 
adopting an allowance for ICIs to use a specific set of reduced testing 
procedures for up to 300 vehicles each year that have been modified to 
a U.S.-certified configuration. This has been allowed for ICIs since 
1999 and was approved under EPA's authority to establish equivalent 
alternate test procedures.\422\ Instead of running a full set of 
emission tests, the reduced-testing requirements allow ICIs to run an 
FTP for exhaust emissions, a highway fuel

[[Page 23539]]

economy test, and the hot soak test and the one-hour diurnal emission 
test that applied prior to the evaporative emission test procedures 
that involve 24-hour cycling of ambient temperatures. We do not believe 
these changes will have any significant cost impacts on ICIs. Most ICIs 
have electric dynamometers or can upgrade for a relatively small cost. 
The reduced testing burden provisions keep the cost of testing low, 
compared to the cost of running a full set of emission tests that would 
otherwise be required.
---------------------------------------------------------------------------

    \422\ See 40 CFR 86.106-96(a) and Enclosure 2 to EPA Guidance 
letter CCD-02-04, February 6, 2002.
---------------------------------------------------------------------------

     We are adopting CARB's onboard diagnostic requirements for 
light-duty vehicles, light-duty trucks, and heavy-duty vehicles at or 
below 14,000 lbs GVWR, as described in Section IV.C.5.d. We currently 
allow for this as an option, and almost all manufacturers do this 
already to avoid certifying multiple systems. Now that we are adopting 
evaporative provisions that are largely based on California's 
regulatory specifications and we are making efforts to adopt a single, 
national regulatory program, we believe this is an appropriate step. 
These changes apply starting in MY 2017 for vehicles subject to Tier 3 
standards. In the case of alternative fuel conversions, we continue to 
apply the requirements of 40 CFR 86.1806-05.
4. Manufacturer In-Use Verification Program (IUVP) Requirements
    The fuel on which an in-use vehicle will be operated and tested is 
considered an integral part of the vehicle's emission control system 
design. The Tier 2 program recognized that to achieve the desired 
emission reductions, vehicles must operate on the same fuel that the 
emission control system was originally designed to encounter in-use and 
during testing. In the Tier 2 program, we acknowledged that during the 
transition of the in-use fuel from sulfur levels of 300 ppm to 30 ppm 
average level, vehicles designed for 30 ppm could encounter in-use 
sulfur levels well above the level for which their emission control 
systems were designed. To address this issue, we allowed manufacturers, 
with agency approval, to perform specific preconditioning test 
procedures during the IUVP testing to ensure that potential exposure to 
high sulfur fuel would not impact the emission test results. These 
procedures included specific drive cycles or maneuvers not regularly 
encountered during normal in-use operation that would result in removal 
of sulfur contamination from the emission control system.
    Consistent with the Tier 2 program, EPA continues to recognize the 
importance of the fuel to the emission control system design, 
particularly on Tier 3 vehicles designed to meet the most stringent 
emission levels of the program (i.e., Bin 70 and cleaner). Under the 
requirements of this final rule, in-use fuel will transition from an 
average sulfur level of 30 ppm to a new average level of 10 ppm. These 
sulfur requirements are average standards. Thus, even after the 
transition to the 10 pm average sulfur level, vehicles may still 
encounter sulfur levels during in-use operation that are above 10 ppm, 
and as high as the 95 ppm cap, which could adversely impact the 
emission control system. Tier 3 vehicles tested by manufacturers in 
IUVP that have been exposed to such sulfur levels could experience 
sulfur-related impacts, which in turn could cause the vehicle to 
temporarily exceed emission standards.
    To address the potential emission impact on Tier 3 vehicles from 
exposure to higher sulfur levels, we are modifying the IUVP testing 
process based in part on what was allowed under the Tier 2 program. 
Tier 3 vehicles tested in the IUVP are to be tested initially without 
allowing any sulfur cleanout procedure, such as a US06 test run prior 
to the FTP or Highway Fuel Economy (HFET) tests. If a vehicle fails the 
NMOG+NOX standard for the FTP or HFET cycle during the 
initial round of testing, manufacturers may perform a sulfur cleanout 
procedure before repeating the FTP or HFET, consisting of up to two 
US06 cycles. The measured US06 cycle and a preconditioning US06 cycle, 
if performed as part of the initial measured tests would serve as the 
cleanout procedure and therefore no additional US06 cycles would be 
allowed. Alternative sulfur cleanout procedures would require EPA 
approval. Following the sulfur cleanout procedure, the manufacturer 
will prep and soak the vehicles and then repeat the FTP and HFET tests. 
Manufacturers choosing to perform the sulfur cleanout procedure would 
need to submit evidence that the vehicle encountered high sulfur levels 
in the fuel just prior to emission testing. This would need to include 
an analysis of a fuel sample from the vehicle fuel system as received 
from in-use operation just prior to testing. If the fuel sample 
indicated that the vehicle had been operating on fuel containing 15 ppm 
or higher sulfur levels, only the emission results of the tests 
following the cleanout procedure would be used to determine emission 
compliance and whether to enter the in-use compliance program (IUCP). 
We intend to monitor the emission results of in-use testing and sulfur-
related test failures to determine if further reductions in the sulfur 
cap are required to ensure that Tier 3 vehicles are meeting the 
standards under in-use driving conditions.
    The changes to the IUVP testing described above apply for light-
duty vehicles, light-duty trucks, and MDPVs. These changes are not 
applicable to heavy-duty vehicles tested in the IUVP program. Also, as 
described in Section IV.D, we are incorporating leak testing into the 
IUVP test protocol.

V. Fuel Program

    Under today's Tier 3 program, we are finalizing reductions in 
gasoline sulfur levels nationwide. These standards will help reduce 
current levels of sulfur that contribute to ambient levels of air 
pollution that endanger public health and welfare. It will also help 
prevent the significant impairment of the emission control systems 
expected to be used in Tier 3 technology, significantly improve the 
efficiency of emissions control systems currently in use, and continue 
prevention of the substantial adverse effects of sulfur levels on the 
performance of vehicle emissions control systems.

A. Overview

1. Background
a. History of Gasoline Sulfur Control
    Sulfur is naturally occurring in crude oil. Crude oil containing 
higher concentrations of sulfur (i.e., greater than 0.5 percent) is 
called ``sour'' and crude containing lower sulfur concentrations (e.g., 
West Texas Intermediate) is referred to as ``sweet.'' Regardless of the 
concentration, because sulfur is naturally occurring in crude oil, it 
is also naturally occurring in gasoline. As discussed in Section IV.A, 
sulfur impairs the performance of today's vehicle emission control 
technologies (i.e., precious metal catalytic converters), reducing the 
emission benefits of current and advanced vehicles. As explained below, 
in 2000 EPA took action to reduce gasoline sulfur levels under what is 
known as the Tier 2 Program \423\ and we are taking further action with 
today's Tier 3 Program.
---------------------------------------------------------------------------

    \423\ 67 FR 6698 (February 10, 2000).
---------------------------------------------------------------------------

    Tier 2 was a major, comprehensive program designed to reduce 
emissions from passenger cars, light trucks, and large passenger 
vehicles (including sport utility vehicles, minivans, vans, and pick-up 
trucks) and the sulfur content of gasoline. Under this program, 
automakers were required to

[[Page 23540]]

manufacture low-emission vehicles when operated on low-sulfur gasoline, 
and refiners were required to produce low-sulfur gasoline nationwide.
    Required reductions in gasoline sulfur under the Tier 2 program 
began in 2004 with refinery and importer caps of 300 ppm and a 
corporate average cap of 120 ppm. For most refiners and importers, 
compliance with the final sulfur standards (30 annual average and 80 
per-gallon cap) was required beginning in 2006. The Tier 2 program was 
fully implemented on January 1, 2011 (the ultra-low sulfur diesel 
program allowed for some extensions of the Tier 2 gasoline program 
flexibility provisions). The Tier 2 gasoline sulfur program also 
included an averaging, banking, and trading (ABT) program that allowed 
companies to generate credits for implementing the required changes 
earlier than their required start date, and allowed ongoing flexibility 
to meet the 30 average sulfur standard.
    At full implementation, the Tier 2 program (treating vehicles and 
fuels as a system) required passenger vehicles to be over 77 percent 
cleaner and gasoline sulfur to be reduced by up to 90 percent from pre-
program levels.
b. Need for Additional Gasoline Sulfur Control
    The authority under which we are lowering the existing gasoline 
sulfur standards comes from Clean Air Act section 211(c)(1). This is 
because emission products of gasoline with current levels of sulfur 
cause or contribute to air pollution which may reasonably be 
anticipated to endanger public health or welfare, and because emission 
products of gasoline with current levels of sulfur will impair to a 
significant degree the emissions control device or systems on the 
vehicles subject to today's final Tier 3 standards. For more on our 
legal authority to set gasoline sulfur standards, refer to Section V.M.
    As explained in Section IV.A, robust data from many sources show 
that gasoline sulfur at current levels (i.e., around 30 ppm on average) 
continues to degrade vehicle catalytic converter performance during 
normal operation. NOX emissions are the most significantly 
affected by this degradation. The NMOG+NOX vehicle emission 
standards, representing an 80 percent reduction from current Tier 2 
standards, will not be possible without the gasoline sulfur controls we 
are finalizing today. Today's 10 ppm sulfur standard should enable 
vehicle manufacturers to certify their entire product line of vehicles 
to the final Tier 3 fleet average standards. Tier 3 vehicles must 
achieve essentially zero warmed-up NOX emissions to comply 
and must maintain this performance for up to 150,000 miles. An increase 
in emissions of only a few milligrams per mile due to sulfur could make 
compliance impossible for some vehicles. The standards are projected to 
be especially challenging for larger SUVs and pick-up trucks. Based on 
testing of these vehicles, as shown in Section IV.A, reducing gasoline 
sulfur to 10 ppm should enable these vehicles to maintain their 
emission performance in-use over their useful life. Lowering gasoline 
sulfur will also help reduce emissions of pollutants that endanger 
public health and welfare from vehicles already on the road today. As 
also discussed above in Section IV.A, we have tested a wide range of 
vehicles to better understand the impact that even lower gasoline 
sulfur could have on emissions. Our test data showed significant 
NOX and VOC reductions when vehicles were tested on low 
sulfur gasoline. As also explained in more detail in Section III.B, 
lowering average gasoline sulfur from 30 to 10 ppm will result in 
approximately 260,000 less tons of NOX and 50,000 less tons 
of VOC almost immediately as the Tier 3 gasoline sulfur standards take 
effect.
2. Summary of Final Tier 3 Fuel Program Standards
    The major elements of the fuel program being finalized today are 
summarized below. Please refer to sections V.B through V.J for more 
discussion on each of the elements summarized here.
a. Annual Average Sulfur Standard
    Under today's final Tier 3 fuel program, gasoline and any ethanol-
gasoline blend will be required to have a sulfur level of 10 ppm or 
less on an annual average basis beginning January 1, 2017. The 10 ppm 
average will apply to a refiner or importer's annual gasoline 
production. Similar to the Tier 2 gasoline program, the Tier 3 program 
applies to gasoline in the United States and the U.S. territories of 
Puerto Rico and the Virgin Islands, excluding California. Please see 
Section V.B for a more detailed discussion of the annual average sulfur 
standard.
b. Per-Gallon Sulfur Caps
    Refiners and importers will continue to be subject to refinery gate 
per-gallon sulfur caps of 80 ppm. Similarly, gasoline downstream of the 
refinery gate (e.g., at terminals, retail stations, etc.) will continue 
to be subject to a 95 ppm per-gallon sulfur cap. We are also committing 
to continue to evaluate if reductions in the per-gallon sulfur caps are 
warranted.
    A more detailed discussion on our decision to continue the current 
80 and 95 ppm per-gallon sulfur caps, and elements of an in-use study, 
can be found below in Section V.C.
c. Small Refiner and Small Volume Refinery Provisions
    As described in further detail in Section V.E.1, approved gasoline 
small refiners and small volume refineries must produce gasoline 
meeting the 10 ppm annual average sulfur standard beginning January 1, 
2020. Small refiners and small volume refineries who meet the 10 ppm 
sulfur standard prior to this date may generate credits for early Tier 
3 program compliance.
d. Averaging, Banking, and Trading (ABT) Program
    Section V.D discusses our averaging, banking, and trading (ABT) 
program. Refiners and importers may continue to generate credits for 
reductions in their gasoline sulfur levels below the current (Tier 2) 
30 ppm average gasoline sulfur standard through December 31, 2016; and 
for reductions below the new 10 ppm average standard beginning January 
1, 2017. These credits can be used for compliance with either the Tier 
2 standard through 2016 or the Tier 3 standard beginning in 2017. The 
Tier 3 ABT program will have similar credit use provisions as the Tier 
2 ABT program. These provisions include: Five-year credit life from the 
year of generation; two-trade limit for inter-company trading; and the 
ability to use credits internally, bank for future use, or trade to 
other refiners/importers. Although credits generated prior to January 
1, 2017 will be valid for five years or until December 31, 2019, 
whichever is earlier.
e. Gasoline Additive Cap
    As discussed further in Section V.C., manufacturers of gasoline 
additives that are used downstream of the refinery at less than 1.0 
volume percent will be required to limit the sulfur contribution to the 
finished gasoline from the use of the additive to less than 3 ppm when 
the additive is used at the maximum recommended treatment rate. For 
each batch of additive produced, the manufacturer must retain sulfur 
test records for 5 years, and must make these records available to EPA 
upon request.
    Parties that introduce additives to gasoline at over 1.0 volume 
percent will be required to satisfy all of the obligations of a refiner 
and fuel manufacturer, including demonstration

[[Page 23541]]

that the finished blend meets the applicable sulfur specification.
f. Requirements for Denatured Fuel Ethanol and Other Gasoline 
Oxygenates
    Today's rule finalizes a 10 ppm sulfur cap for denatured fuel 
ethanol (DFE). While DFE is the predominant gasoline oxygenate 
currently in use, these standards also apply to other gasoline 
oxygenates. Today's rule finalizes a 3.0 volume percent limit on 
ethanol denaturant concentration. We are adopting the current ASTM 
International specifications that only natural gasoline, gasoline 
blendstocks, or gasoline may be used as denaturants for DFE.\424\ As 
discussed in the Summary and Analysis of Comments, we believe it is not 
necessary to finalize the proposed additional limits on the potential 
denaturants that may be used at this time. We are also finalizing 
regulatory text to state that DFE must be composed solely of carbon, 
hydrogen, oxygen, and sulfur. Testing, recordkeeping, and reporting 
obligations are also being finalized to implement these new standards 
as discussed in Section V.G. Sulfur testing using approved analytical 
methods or volumetric blending records and denaturant product transfer 
documents (PTDs) can be used by manufacturers/importers of DFE in 
demonstrating compliance with the 10 ppm sulfur cap for DFE finalized 
today.
---------------------------------------------------------------------------

    \424\ ASTM D4806-13a, ``Standard Specification for Denatured 
Fuel Ethanol for Blending with Gasoline for Use as Automotive Spark-
Ignition Engine Fuel''.
---------------------------------------------------------------------------

g. Fuel Used in Flexible Fuel Vehicles
    As discussed in Section V.H., we are deferring finalizing 
additional fuel quality requirements for E16-50 and E51-83 at this 
time. We continue to believe in the importance of implementing 
additional fuel quality standards for higher-level ethanol blends and 
will continue to work with stakeholders in their development following 
the publication of this final rule.
h. Standards for Butane and Pentane
    As discussed further in Section V.I, we are finalizing a 10 ppm 
sulfur cap for butane blended into gasoline effective January 1, 2017. 
This is consistent with the Tier 3 10 ppm refinery average sulfur 
specification finalized today. In addition, as discussed below in 
Section VI.A.4, we are also finalizing provisions to allow pentane to 
be blended into gasoline downstream of the refinery. These provisions 
are similar to the existing provisions for butane blending. This 
allowance will become effective June 27, 2014; a 30 ppm sulfur cap will 
apply to pentane blended into gasoline (consistent with the existing 
sulfur cap for butane under the Tier 2 program) until December 31, 
2016, after which a 10 ppm sulfur cap will apply.
i. CNG/LPG
    As discussed below in Section V.J., we are deferring establishing 
in-use sulfur requirements for compressed natural gas (CNG) and liquid 
propane gas (LPG) to provide additional time to work with stakeholders 
to collect data on current CNG/LPG sulfur content; to determine whether 
additional control of in-use CNG/LPG sulfur content is needed; and to 
evaluate the feasibility and costs associated with potential additional 
sulfur controls.

B. Annual Average Sulfur Standard

    Under today's final Tier 3 fuel program, gasoline and any ethanol-
gasoline blend will be required to have a sulfur level of 10 ppm or 
less on an annual average basis beginning January 1, 2017. The 10 ppm 
average will apply to a refiner or importer's annual gasoline 
production. Similar to the Tier 2 gasoline program, the Tier 3 program 
applies to gasoline in the United States and the U.S. territories of 
Puerto Rico and the Virgin Islands, excluding California. We are 
finalizing the 10 ppm average sulfur standard both to enable the new 
vehicle fleet to meet the Tier 3 vehicle standards being finalized 
today pursuant to CAA section 211(c)(1)(B), and to reduce emissions 
from the existing in-use vehicle fleet that endanger public health and 
welfare pursuant to section 211(c)(1)(A) of the Clean Air Act (CAA).
    We received numerous comments both in support of and against the 
proposed 10 ppm annual average sulfur standard. Commenters opposing the 
standard believe that 10 ppm is too low and/or is not needed to enable 
Tier 3 vehicle technologies. Some commenters suggested that EPA should 
consider setting a less stringent sulfur standard than the proposed 10 
ppm annual average (detailed information regarding the comments can be 
found in the Summary and Analysis of Comments document, which is 
located in the docket for this rulemaking). We believe that a 10 ppm 
annual average standard will help reduce current levels of sulfur that 
contribute to ambient levels of air pollution that endanger public 
health and welfare. It will also help prevent the significant 
impairment of the emission control systems expected to be used in Tier 
3 technology, significantly improve the efficiency of emissions control 
systems currently in use, and continue prevention of the substantial 
adverse effects of sulfur levels on the performance of vehicle 
emissions control systems. This level is also feasible, and is the 
level that appropriately balances costs with the emission reductions 
that it provides and enables.
    As discussed in Section IV.A.6., and further in Chapter 5 of the 
RIA, we believe that a standard of 10 ppm is appropriate, and when 
combined with the advances in emissions control technologies will be 
sufficient to meet the Tier 3 emissions standards. The feasibility of 
the 30 mg/mi NMOG+NOX fleet average depends on exhaust 
catalyst systems that require gasoline with average sulfur levels of 10 
ppm or less. Further, annual average sulfur levels greater than 10 ppm 
would significantly impair the emission control technology that we 
expect will be used to meet the Tier 3 standards and to ensure in-use 
compliance over a vehicle's useful life. This is particularly a concern 
for some larger vehicles that will need to reduce NOX to 
near-zero levels, due to greater difficulty in reducing cold-start 
NMOG, in order to meet a combined NMOG+NOX standard. As 
discussed in Section IV.A.6, increasing gasoline sulfur from 10 ppm to 
20 ppm or 30 ppm would make it impossible for vehicle manufacturers to 
meet the Tier 3 standards. Achieving Tier 3 standards would require 
offsetting the resultant higher emissions but EPA is not aware of 
existing technology or developing technology that could address these 
higher emissions when taking into consideration the entire vehicle 
fleet. Increasing gasoline sulfur from 10 ppm to 20 ppm or 30 ppm would 
also forego the very large immediate reductions from the existing 
fleet.
    We also do not believe a sulfur standard lower than 10 ppm is 
necessary to enable vehicles to meet the Tier 3 standards. As also 
discussed in Section IV.A, reducing sulfur below 10 ppm would further 
reduce vehicle emissions and allow the Tier 3 vehicle standards to be 
achieved more easily. However, we believe that a 10 ppm average 
standard is sufficient to allow vehicles to meet the Tier 3 standards. 
Furthermore, as discussed below, there are significant challenges 
associated with reducing sulfur below 10 ppm.
    As explained in Section IV.A, sulfur in fuel oxidizes in the 
exhaust and coats the sites where chemical reactions can take place on 
the precious metal catalysts used in vehicles to reduce emissions of 
VOC, NOX, PM, CO, and toxics. Accordingly, any sulfur in 
gasoline causes vehicle emissions to

[[Page 23542]]

increase. Sulfur can be burned off the catalyst during high-
temperature, rich operation of the vehicle (i.e., aggressive driving 
conditions), but as long as there is any sulfur in the fuel, exhaust 
emissions will increase. Because any amount of sulfur in the fuel can 
have this effect, the lower the sulfur the better. Refiners experience 
the same phenomenon with precious metal catalysts used in the reformer 
and isomerization units at their refineries.\425\ To protect the 
precious metal catalysts in these units, refiners reduce the sulfur in 
the feed to these units to 1 ppm or below. Thus, it is technically 
possible for refiners to reduce their gasoline sulfur levels to 
virtually zero. While refiners did not have reason to reduce the sulfur 
in FCC gasoline until Tier 2 required such reductions, some refiners 
have achieved reductions in this stream at some of their refineries for 
other reasons such as: (1) Protecting the FCC catalyst from the 
contaminants in the gas oil feed, (2) reducing stack emissions from the 
regenerator of the FCC unit, and most importantly (3) increasing 
gasoline yields from the FCC unit. For most refineries, FCC gasoline 
accounts for about one-third of gasoline and before Tier 2 was the 
source of over 95 percent of the sulfur in gasoline. Under Tier 2, most 
refiners significantly desulfurized FCC gasoline to around 70 to 80 
ppm, yet FCC gasoline continues to contribute the majority of sulfur in 
gasoline today.
---------------------------------------------------------------------------

    \425\ Together, the streams from the reformer and isomerization 
units account for approximately one-third of gasoline.
---------------------------------------------------------------------------

    An annual average sulfur level of 10 ppm will achieve very large 
immediate reductions from the existing fleet, as discussed in Sections 
III and IV. Because any sulfur in gasoline will continue to impair 
vehicle catalyst performance, reducing sulfur levels to zero would 
maximize vehicle emission reductions. However, there are two reasons 
why we believe a 10 ppm average sulfur standard is sufficient and 
further reductions (e.g., 10 ppm cap or 5 ppm average) are not 
necessary at this time. First, our analysis shows that a 10 ppm annual 
average is sufficient to enable vehicles to reach the Tier 3 standards. 
Consequently, while reducing sulfur levels further would continue to 
yield reductions from the in-use fleet, they would not be necessary to 
enable the new Tier 3 vehicle standards to be met. Second, while sulfur 
levels would continue to reduce emissions from the existing fleet, 
reducing sulfur further below 10 ppm becomes increasingly difficult and 
costly. FCC naphtha is very rich in high-octane olefins. As the 
severity of desulfurization increases, more olefins are saturated, 
further sacrificing the octane value of this stream and further 
increasing hydrogen consumption. Making up for this lost octane 
represents a significant portion of the sulfur control costs. 
Furthermore, as desulfurization severity increases, there is an 
increase in the amount of sulfur removed (in the form of hydrogen 
sulfide) which recombines with the olefins in the FCC naphtha, thus 
offsetting the principal desulfurization reactions. There are means to 
deal with the recombination reactions, but they result in even greater 
capital investments. In addition, while FCC gasoline contributes the 
majority of sulfur to the finished gasoline, as the sulfur level drops 
below 10 ppm, the sulfur level of the various other gasoline streams 
within the refinery also become important. Any necessary treatment of 
these additional streams increases both capital and operating costs.
    U.S. refineries are currently in different positions, both 
technically and financially. In general, they are configured to handle 
the different crude oils they process and turn them into a widely 
varying product slate to match available markets. Those processing 
heavier, sour crudes may have a more challenging time reducing gasoline 
sulfur under the Tier 3 program. Also, those with higher sulfur levels 
in other refinery streams may have a more difficult time desulfurizing 
gasoline. Perhaps most important, U.S. refineries vary greatly in size 
(atmospheric crude capacities range from less than 5,000 to more than 
500,000 barrels per day) and thus have different economies of scale for 
adding capital to their refineries. Therefore, it can be less costly 
per gallon for some larger refineries to get down to 10 ppm than for 
smaller refineries, as discussed in Chapter 5 of the RIA. As a result, 
with a 10 ppm average standard, the flexibility afforded by the ABT 
program helps those refineries with very high costs. They have the 
option of staying above 10 ppm if they can acquire credits from other 
refineries that were able to lower their sulfur level below 10 ppm. 
However, if the gasoline sulfur standard were lower, this would 
essentially end the ability of refiners to average sulfur reductions 
across their refineries. There simply would not be enough opportunity 
to generate credits at levels much below 10 ppm.
    As discussed further in Chapter 5 of the RIA, we assessed the 
potential costs of an annual average standard lower than 10 ppm (e.g., 
5 ppm). Our analysis shows that sulfur control costs for refineries to 
meet a standard below 10 ppm could be on the order of two times more 
costly per ppm-gallon of gasoline sulfur reduced. In addition, a 
standard below 10 ppm could be cost-prohibitive for more challenged 
refineries. Further, such a standard would also introduce additional 
costs to address the contribution to gasoline sulfur from gasoline 
additives, transmix, ethanol denaturants, and contamination in the 
distribution system.
    Therefore, we believe that the 10 ppm annual average standard will 
help reduce current levels of sulfur that contribute to ambient levels 
of air pollution that endanger public health and welfare. It will also 
help prevent significant impairment of the emission control systems 
expected to be used in Tier 3 technology, significantly improve the 
efficiency of emissions control systems currently in use, and continue 
prevention of the substantial adverse effects of sulfur on the 
performance of vehicle emissions control systems. The level is also 
feasible (especially considering its associated ABT provisions, 
described in Section V.D), and is the point which appropriately 
balances costs with the emission reductions that it provides and 
enables.

C. Per-Gallon Sulfur Caps

1. Standards
    The final Tier 3 program is composed of a 10 ppm refinery annual 
average sulfur standard (discussed above in Section V.B) with an 80 ppm 
per-gallon cap at the refinery gate and a 95 ppm per-gallon cap 
downstream; these per-gallon caps currently exist under the Tier 2 
program. We believe this is the most prudent approach for lowering in-
use sulfur while maintaining flexibility considering cost and other 
factors. These per-gallon caps are important in the context of an 
average sulfur standard to provide an upper limit on the sulfur 
concentration that vehicles must be designed to tolerate. The caps also 
limit downstream sulfur contamination and enable the enforcement of the 
gasoline sulfur standard in-use. Our 10 ppm average standard with 
higher per-gallon caps compares to a 10 ppm cap standard in much of 
Europe, Japan, and Korea. In addition to the gasoline standards we are 
finalizing today, we are also finalizing caps on the sulfur content of 
gasoline additives, to limit their contribution to the overall in-use 
gasoline sulfur level.
a. What We Proposed
    We proposed two options for the per-gallon sulfur caps--maintaining 
the Tier 2 80 ppm refinery gate sulfur and 95

[[Page 23543]]

ppm downstream sulfur caps and, beginning January 1, 2020, lowering to 
50 ppm refinery gate and 65 ppm downstream caps. The 50 ppm refinery 
gate cap was proposed to take effect on January 1, 2020, as this is the 
date when the small refiner, small volume refinery, and early credit 
use provisions would expire; and also to avoid forcing additional 
refinery investments during the early credit usage period. We also 
requested comment on lowering the caps to 20 ppm at the refinery gate 
and 25 ppm downstream.
    We received comments on both of the proposed per-gallon cap options 
of 80/95 ppm and 50/65 ppm, as well as comments on finalizing lower 
caps of 20/25 ppm and a 20 ppm overall cap. Comments supporting lower 
caps noted potential environmental benefits, greater certainty that 
vehicles would see lower and more uniform gasoline sulfur levels, and 
enabling new vehicle technologies that require very low sulfur levels. 
Comments in support of maintaining the current Tier 2 caps cited 
concerns on cost, flexibility for turnarounds/unplanned shut downs (due 
to refinery fire, natural disaster, etc.), and potential impacts on 
gasoline supply and pricing. Detailed information regarding the 
comments we received on the per-gallon sulfur caps is provided in the 
Summary and Analysis of Comments document, which is available in the 
rulemaking record.
b. Final Refinery Gate Sulfur Cap
    In today's action, we are retaining the 80 ppm refinery gate cap. 
The refinery gate cap provides flexibility for batch-to-batch 
variability that naturally occurs at a refinery due to the varying 
types of crude that refineries process, variations in unit operations, 
and variations in product mix. It further provides for flexibility 
during unit turnarounds, and unplanned upsets (e.g., refinery fires, 
natural disasters, etc.), to avoid a complete refinery shutdown. A 
lower cap could create situations where refiners would need to store 
more off-spec gasoline for future processing. However, if a refinery 
does not have adequate tankage for storing this product, and/or if its 
processing units are not large enough to ``catch up'' in refining off-
spec product, it could result in significant impacts to fuel pricing or 
supply. For a refiner that produces multiple products, any potential 
supply impacts could also impact other fuel markets (e.g., diesel, jet 
fuel, etc.). Additionally, the refinery gate cap is a ``hard'' limit--a 
refinery's actual production has to be well below this limit to account 
for in-use testing tolerances, safety margins, and any additives that a 
refiner may need to add prior to the fuel leaving the refinery. An 80 
ppm refinery gate cap will provide refiners needed flexibility, and 
more certainty that they will be able to continue producing and 
distributing at least some gasoline during turnarounds/upsets to avoid 
a total shutdown. It will further provide more certainty for transmix 
processors, additive manufacturers and other downstream parties.
    As described below in Section VII, we believe that most refineries 
would not have significant costs as a result of the Tier 3 program 
because they will be able to meet the 10 ppm average sulfur standard 
largely through revamps and operational changes at their facilities, 
rather than installing grassroots units. Lowering to a cap of 50 ppm 
would directionally increase the costs of the Tier 3 program. The 
American Petroleum Institute (API) provided a detailed study with their 
comments \426\ quantifying the additional costs associated with 
successively more stringent per-gallon caps. While we do not agree with 
the study's overall cost analysis, we do agree that with a refinery 
gate cap of 50 ppm, a number of refiners would incur higher capital 
costs due to the decreased ability to handle off-spec product with a 
lower refinery gate cap. As refiners must ensure that they can continue 
to produce saleable product and meet demand in the event of an upset or 
an off-spec batch of fuel, the need for installation of additional 
tankage and/or increased refinery processing capability would be 
greater with a 50 ppm refinery gate cap. While at the time of the 
proposal we believed that a cap of 50 ppm would have little cost 
impact, our more recent analysis shows that a 50 ppm cap would increase 
the cost of the Tier 3 gasoline sulfur standards by approximately 10 
percent (see RIA Chapter 5.2.2.4). At the same time, the more stringent 
cap with its associated increase in cost would be unlikely to provide 
significant additional emission benefits nationwide. As discussed 
previously in Sections III and IV above, the emissions benefits 
associated with the Tier 3 program are mainly driven by the reduction 
in the average sulfur content of gasoline from 30 to 10 ppm, since 
vehicle emissions are proportional to the sulfur content of the fuel. 
Changes in the cap would not affect this. In the context of the final 
ABT provisions, a higher cap does allow for increases in emissions on a 
temporal basis as one batch of fuel is allowed to have higher sulfur 
levels. However, this is then offset by reductions in emissions from 
batches of fuel that are then required to be below the 10 ppm average 
standard. Similarly, the final ABT provisions allow for the possibility 
that the fuel from different refineries will cause varying emission 
reductions as one refinery's higher average sulfur levels would lead to 
less emission reductions in-use. However, this is then offset by 
greater reductions in emissions due to the fuel produced by refineries 
with sulfur levels below the average standard.
---------------------------------------------------------------------------

    \426\ ``Economic and Supply Impacts of a Reduced Cap on Gasoline 
Sulfur Content; Prepared for the American Petroleum Institute''; 
Turner, Mason & Company. Document number: EPA-HQ-OAR-2011-0135-4285; 
API-AFPM Attachment 13.
---------------------------------------------------------------------------

    Based on our cost analysis, which is discussed below in Section 
VII.B., we project nearly 40% of the gasoline pool would be at 5 ppm, 
about 45% at 10 ppm and the remaining approximately 15% at levels 
higher than 10 ppm. The sulfur level for this 15% in our analysis 
ranges from 11 ppm all the way up to 70 ppm. However, as discussed in 
Section VII.B., these high sulfur levels are more a function of the 
limitations of our analysis where we could only model these refineries 
as remaining at their current Tier 2 sulfur levels. We anticipate that 
in most (if not all) cases refineries will make operational changes 
and/or investments in order to reduce their credit burden and reduce 
their compliance costs. This anticipation, along with the fact that a 
10 ppm average standard by definition limits the amount of gasoline 
that can remain at higher sulfur levels (regardless of the cap), means 
that we anticipate most refineries, including those using credits, will 
still average less than 20 or 30 ppm in their physical gasoline 
production. Nevertheless, the final ABT program does allow for the 
possibility (regardless of the cap) that were this higher sulfur fuel 
to be concentrated in any certain geographical area, it would not 
receive the full emission reductions from the Tier 3 program. We have 
considered the potential for areas to consistently receive fuel that 
might be predominantly higher than the 10 ppm average. Because 
refineries generating credits and using credits are interspersed across 
the country, and because most areas receive a considerable portion of 
their fuel by pipeline, barge, rail, or truck from refineries in other 
areas, we expect the variation in average sulfur levels across the 
country to be too limited to warrant lowering the per-gallon cap to 50 
ppm. Given the stringency of the 10 ppm average standard, we predict 
that in-use

[[Page 23544]]

sulfur levels will generally be well below 50 ppm.
    Further reductions in the refinery gate cap are also not needed to 
enable the vehicle emissions standards, as the vehicle standards are a 
function of the 10 ppm annual average sulfur standard. While vehicle 
manufacturers have expressed concerns about the potential impacts on 
emissions performance if individual vehicles are exposed to gasoline 
above 10 ppm due to higher per-gallon caps and/or credit usage,\427\ we 
believe that vehicles will see sulfur levels closer to the 10 ppm 
average rather than the 80 ppm cap due to the fact that the 10 ppm 
average will drive reductions in gasoline sulfur levels.
---------------------------------------------------------------------------

    \427\ Alliance of Automobile Manufacturers (2011, October 6). 
Letter to EPA Administrator, Lisa Jackson.
---------------------------------------------------------------------------

    Thus, we believe it is prudent at this time to retain an 80 ppm 
refinery gate cap. However, we are committing to monitor and further 
evaluate in-use sulfur levels and their impact on vehicle emissions. If 
it is warranted, we will reassess the sulfur cap level and the need for 
potential future regulatory action. Such ongoing evaluation will 
include analyses of: In-use fuel surveys; batch data that refineries 
are required to submit; and the sulfur credit market. It will also 
include the evaluation of any issues or concerns that might arise 
during implementation of the program. Finally, we will also carry out 
an ongoing evaluation of data submitted by the vehicle manufacturers on 
the performance of their Tier 3 vehicles in-use.
c. Downstream Sulfur Cap
    With regard to the downstream sulfur cap, we believe that 
maintaining a 15 ppm differential between the refinery gate sulfur cap 
and the downstream sulfur cap will provide pipeline operators, transmix 
processors, and gasoline additive users the same flexibility as was 
provided under the Tier 2 program. As was the case under the Tier 2 
program, allowing a 15 ppm differential is needed to ensure adequate 
flexibility in accommodating gasoline produced from transmix, instances 
of contamination during distribution, and for the use of necessary 
(sulfur-containing) additives. In rare circumstances when the sulfur 
contribution from all these sources are coincidently at their maximum 
levels, a very limited number of batches of gasoline at the 95 ppm 
downstream sulfur cap may be present in the distribution system. 
However, we expect that this will not have a substantial impact on the 
average sulfur content of in-use gasoline. Comments received on this 
issue were generally in support of maintaining the 15 ppm delta.
    Pipeline operators are currently allowed to blend limited volumes 
of transmix into gasoline in their systems provided that the resulting 
gasoline meets all fuel quality specifications and the endpoint of the 
blended gasoline does not exceed 437[emsp14][deg]F.\428\ This enables 
pipeline operators to avoid the installation of additional transmix 
storage and loading equipment at a number of remote locations to 
facilitate shipping small volumes of transmix to processing facilities 
by truck.
---------------------------------------------------------------------------

    \428\ The requirements for transmix blenders are contained in 40 
CFR 80.84(d). 437[emsp14][deg]F is the maximum endpoint allowed for 
gasoline in ASTM D4814.
---------------------------------------------------------------------------

    Currently transmix processors must produce gasoline sufficiently 
below the 95 ppm downstream sulfur cap to accommodate any downstream 
sulfur increases from the use of gasoline additives and contamination 
from further distribution. The sulfur content of the gasoline produced 
by transmix processors is determined by the sulfur content of the 
transmix they receive, which in turn is primarily a function of the 
sulfur content of gasoline and jet fuel components in the 
transmix.\429\ Transmix processors do not handle sufficient volumes to 
support the installation of currently available desulfurization 
units.\430\
---------------------------------------------------------------------------

    \429\ Transmix is a by-product of the multi-product pipeline 
distribution system. 40 CFR 80.84(a) defines transmix pipeline 
interface that does not meet the specifications for a fuel that can 
be used or sold, and that is composed solely of any combination of: 
Previously certified gasoline (including previously certified 
gasoline blendstocks that become gasoline solely upon the addition 
of an oxygenate); distillate fuel; or gasoline blendstocks that are 
suitable for use as a blendstock without further processing.
    \430\ Transmix processors produce ~0.1 percent of the gasoline 
consumed in the U.S.
---------------------------------------------------------------------------

d. Accounting for Ethanol Blending in the Determination of Compliance 
With Gasoline Sulfur Requirements
    In demonstrating compliance with the gasoline sulfur standards 
finalized today, gasoline refiners and importers may adjust the sulfur 
levels in the gasoline and blendstocks for oxygenate blending (BOBs) 
that they produce/import to account for the downstream addition of 
ethanol. We proposed that the sulfur content of denatured fuel ethanol 
(DFE) used for downstream blending would be assumed to be 10 ppm in 
making such demonstrations of compliance. Refiners commented that 
refiners and importers should be allowed to either use the actual 
sulfur value of the DFE or conduct laboratory hand blends of a 
representative sample of DFE to determine the effect on the sulfur 
content of the blended fuel from the addition of DFE. We agree that 
refiners and importers should be allowed to use the actual sulfur 
content of DFE when a sulfur test result is available and when the 
refiner can demonstrate that the test result was derived from a 
representative sample of the DFE that was blended with the gasoline or 
BOB. The sulfur content of in-use DFE will typically be lower than the 
10 ppm sulfur cap finalized today for DFE. We assumed that DFE would 
have an average sulfur content of 5 ppm in conducting the refinery 
analysis to support this rule. Therefore, today's final rule requires 
that in determining their compliance with today's sulfur standards, 
refiners and importers must either use the actual sulfur content of the 
DFE established through testing of the DFE actually blended or assume a 
5 ppm sulfur content for the DFE added downstream. To prevent potential 
bias, a refiner or importer must choose to use only one method during 
each annual compliance period.
2. Requirements for Gasoline Additives
    Today's action finalizes the requirement that manufacturers of 
gasoline additives used downstream of the refinery at less than 1 
volume percent must limit the sulfur contribution to the finished 
gasoline from the use of their additive to no more than 3 ppm when the 
additive is used at the maximum recommended treatment rate. The 
additive manufacturer will be required to maintain records of its 
additive production quality control activities which demonstrate that 
the sulfur content of additive production batches is such that when the 
additive is used at its maximum recommended treatment rate it will add 
no more than 3 ppm to sulfur content of the finished gasoline. We 
received comments in support of our proposed requirements (these 
comments can be found in the docket to this rulemaking, and are 
summarized in the Summary and Analysis of Comments document, which is 
also located in the docket). An environmental organization commented 
that the sulfur contribution from additives can have a material effect 
on emissions performance given the level of vehicle emissions control 
that is being finalized today. We also received comments from gasoline 
additive manufactures were in favor of the proposed controls.
    The requirements finalized today are designed to prevent the 
potential dumping of high sulfur materials into

[[Page 23545]]

gasoline under the guise of the addition of gasoline additives. We 
continue to believe that all current gasoline additives contribute less 
than 3 ppm to the sulfur content of the finished fuel when used at the 
maximum recommended treatment rate (with 3 ppm being the extreme). 
Normal additive production quality control practices already have had 
to consider the sulfur contribution of the additive to finished 
gasoline as a result of the Tier 2 gasoline sulfur requirements. The 
maximum recommended treatment rate is already stated on product 
transfer document or packaging for the additive. Additive manufacturers 
are to retain production quality control records for 5 years and make 
these available to EPA upon request. Therefore, the requirements 
finalized today will not constrain the use of genuine gasoline 
additives or result in significant additional costs to gasoline 
additive manufacturers. Parties that introduce additives to gasoline at 
over 1.0 volume percent are required to satisfy all of the obligations 
of a refiner and fuel manufacturer including demonstration that the 
finished blend meets the applicable sulfur specification.
    We also received comments from an environmental organization 
requesting that EPA promulgate limits on the combined sulfur 
contribution for all additives blended into a batch of gasoline in 
addition to controlling the sulfur contribution from individual 
additives. We believe that such additional controls are not necessary, 
would add an unwarranted additional compliance burden, and could 
interfere with the use of necessary downstream additives. Certain 
additives that provide critical fuel performance characteristics (e.g., 
corrosion control, demulsifiers) contain sulfur-containing compounds as 
an essential functional component. Such additives are used to remedy 
specific instances of gasoline quality problems, and their treatment 
rate is governed by the desire to limit the added cost from their use.

D. Averaging, Banking, and Trading Program

    In today's rule, we are finalizing an ABT program that will reduce 
the compliance costs and promote the feasibility of the Tier 3 gasoline 
sulfur program, because it will allow refiners and importers to choose 
the most economical compliance strategy (i.e., investment in 
technology, credits, or both) to meet the 10 ppm average sulfur 
standard. In response to comments received on our proposal, we have 
simplified and added flexibility to the ABT program. The ABT program 
allows refiners and importers to continue to generate credits for 
overcompliance with the current Tier 2 30 ppm average gasoline sulfur 
standard through 2016, and the new 10 ppm average standard beginning in 
2017. (Small refiners and small volume refineries have a January 1, 
2020 compliance date, as described below.) These credits can be used 
for compliance with either the Tier 2 standard through 2016 or the Tier 
3 standard beginning in 2017. Credits can also be banked for future use 
or transferred to other refineries for compliance with the average 
sulfur standard. In addition, we are allowing refiners and importers to 
also use any valid credits banked from 2012 and 2013 under the Tier 2 
program toward compliance with either the Tier 2 or Tier 3 sulfur 
programs. We believe these provisions will provide a seamless 
transition from Tier 2 to the Tier 3 program.
1. How will the ABT program assist with compliance?
    The Tier 3 ABT program allows refiners and importers the 
flexibility to: (1) Have varying gasoline sulfur levels for their 
batches of fuel as long as they