At railroad crossings that have the standard, octagonal, red-and-white stop sign, drivers must stop and proceed only when

At crossings marked with automatic flasher units or automatic crossing gates, drivers must stop if the lights are flashing or the gates are lowered, and they must remain stopped until the lights stop flashing or the gates are raised. At crossings that have the standard octagonal red-and-white stop sign, drivers must stop and proceed only when they determine that no train is approaching, the railroad is clear from the pedestrians and it is safe to cross.