(a) The draws of the bridges across the Missouri River shall open on signal; except during the winter season between the date of closure and the date of opening of the commercial navigation season as published by the Army Corps of Engineers, the draw need not open unless at least 24 hours advance notice is given.

(b) The draw of the Atchison Railroad Bridge, Mile 422.5, Missouri River need not open unless a two-hour advance notice is given during the commercial navigation season.