(1) (a) Except as provided in subsection (1)(b), the driver of a motor vehicle carrying seven or more passengers for hire, a school bus with or without passengers, or a vehicle carrying explosive substances or flammable liquids as a cargo or part of a cargo, before crossing at grade any track or tracks of a railroad, shall stop the vehicle as close as practicable but not less than 15 feet from the nearest rail of the railroad and while stopped shall open the door, in the case of a school bus, and shall listen and look in both directions along the track for an approaching train or other on-track equipment and for signals indicating the approach of a train or other on-track equipment and may not proceed until the driver can do so safely. After stopping as required in this section and upon proceeding when it is safe to do so, the operator of a vehicle may cross only in a gear of the vehicle that requires no changing gears while traversing the crossing. The operator may not shift gears while crossing the track or tracks.
(b) A stop is not required at a crossing where a police officer, highway patrol officer, or official traffic control device directs traffic to proceed.
(2) As used in this section, "official traffic control device" does not include a railroad grade crossing signal.