Every commercial motor vehicle other than those listed in §392.10 shall, upon approaching a railroad grade crossing, be driven at a rate of speed which will permit said commercial motor vehicle to be stopped before reaching the nearest rail of such crossing and shall not be driven upon or over such crossing until due caution has been taken to ascertain that the course is clear.

[33 FR 19732, Dec. 25, 1968, as amended at 60 FR 38747, July 28, 1995]