(A) Except as provided in subsection (B), the driver of a school bus or a motor vehicle with a capacity of sixteen or more persons, a vehicle permitted by the Department of Health and Environmental Control to carry hazardous waste and a vehicle described in regulations issued pursuant to subsection (C), before crossing at grade any tracks of a railroad, shall stop the vehicle within fifty feet, but not less than fifteen feet, from the nearest rail of the railroad and while stopped shall listen and look in both directions along the track for an approaching train and for signals indicating the approach of a train and shall not proceed until he can do so safely. After stopping and upon proceeding when it is safe to do so, the driver of the vehicle shall cross only in the gear of the vehicle that there is no necessity for manually changing gears while traversing the crossing and the driver shall not manually shift gears while crossing the tracks.

(B) Except for school buses, the provisions of this section do not apply at:

(1) a railroad grade crossing where traffic is controlled by a police officer or human flagman;

(2) a railroad grade crossing where traffic is regulated by a traffic-control signal;

(3) a railroad grade crossing protected by crossing gates or an alternately flashing light signal intended to give warning of the approach of a railroad train when the gate or flashing signal does not indicate the approach of a train;

(4) a railroad grade crossing where an official traffic-control device gives notice that the stopping requirement imposed by this section does not apply.