(a) When fog prevails by day or by night, the drawtender of each bridge listed in this section, after giving the acknowledging signal to open, shall toll a bell continuously during the approach and passage of vessels.

(b) The draw of the Puget Sound and Pacific railroad bridge, mile 0.1 at Aberdeen, shall be maintained in the fully open position, except for the passage of trains or for maintenance. When the draw of the bridge is closed and the visibility at the drawtender's station is less than one mile up or down the channel, the drawtender shall sound two prolonged blasts every minute. When the draw is reopened, the drawtender shall sound one prolonged blast followed by one short blast.

(c) The draws of the Heron Street Bridge, mile 0.2, and the Wishkah Street Bridge, mile 0.4, at Aberdeen, shall open on signal if a least one hour notice is given by marine radio, telephone, or other suitable means to the Washington Department of Transportation. The opening signal for both bridges is one prolonged blast followed by two short blasts.

(d) The draws of the Heron Street Bridge, mile 0.2, shall open on signal if at least 48 hours notice is provided. The draw of the Wishkah Street Bridge, mile 0.4, shall open on signal if at least one hour notice is provided. The opening signal for both bridges is one prolonged blast followed by two short blasts.