(1) Whenever any person driving a vehicle approaches a railroad grade crossing under any of the circumstances stated in this section, the driver of such vehicle shall stop within fifty feet but not less than fifteen feet from the nearest rail of such railroad, and shall not proceed until the crossing can be made safely. The foregoing requirements shall apply when:
(a) A clearly visible electric or mechanical signal device gives warning of the immediate approach of a railroad train;
(b) A crossing gate is lowered or when a human flagger gives or continues to give a signal of the approach or passage of a railroad train;
(c) An approaching railroad train is plainly visible and is in hazardous proximity to such crossing. (2) No person shall drive any vehicle through, around or under any crossing gate or barrier at a railroad crossing while such gate or barrier is closed or is being opened or closed.