(a) States with areas subject to this subpart and part 93, subpart A, of this chapter must submit to the EPA and DOT a revision to their implementation plan which contains criteria and procedures for DOT, MPOs and other State or local agencies to assess the conformity of transportation plans, programs, and projects, consistent with this subpart and part 93, subpart A, of this chapter. This revision is to be submitted by November 25, 1994 (or within 12 months of an area's redesignation from attainment to nonattainment, if the State has not previously submitted such a revision). Further revisions to the implementation plan required by amendments to part 93, subpart A, of this chapter must be submitted within 12 months of the date of publication of such final amendments. EPA will provide DOT with a 30-day comment period before taking action to approve or disapprove the submission. A State's conformity provisions may contain criteria and procedures more stringent than the requirements described in this subpart and part 93, subpart A, of this chapter only if the State's conformity provisions apply equally to non-federal as well as Federal entities.

(b) The Federal conformity rules under part 93, subpart A, of this chapter, in addition to any existing applicable State requirements, establish the conformity criteria and procedures necessary to meet the requirements of Clean Air Act section 176(c) until such time as EPA approves the conformity implementation plan revision required by this subpart. Following EPA approval of the State conformity provisions (or a portion thereof) in a revision to the applicable implementation plan, conformity determinations would be governed by the approved (or approved portion of the) State criteria and procedures. The Federal conformity regulations contained in part 93, subpart A, of this chapter would apply only for the portion, if any, of the State's conformity provisions that is not approved by EPA. In addition, any previously applicable implementation plan conformity requirements remain enforceable until the State submits a revision to its applicable implementation plan to specifically remove them and that revision is approved by EPA.

(c) The implementation plan revision required by this section must meet all of the requirements of part 93, subpart A, of this chapter.

(d) In order for EPA to approve the implementation plan revision submitted to EPA and DOT under this subpart, the plan must address all requirements of part 93, subpart A, of this chapter in a manner which gives them full legal effect. In particular, the revision shall incorporate the provisions of the following sections of part 93, subpart A, of this chapter in verbatim form, except insofar as needed to clarify or to give effect to a stated intent in the revision to establish criteria and procedures more stringent than the requirements stated in the following sections of this chapter: §§ 93.101, 93.102, 93.103, 93.104, 93.106, 93.109, 93.110, 93.111, 93.112, 93.113, 93.114, 93.115, 93.116, 93.117, 93.118, 93.119, 93.120, 93.121, 93.126, and 93.127.