Before a level crossing, two red lights flashing alternately indicate...

Correct answer

that passage is temporarily prohibited.

Before a level crossing, the presence of two red lights flashing alternately indicates that passage is temporarily prohibited. Temporary prohibition of passage: flashing red lights warn that the level crossing must not be crossed at that moment. This prohibition is for safety reasons, generally because a train is approaching. Common locations for these signals: In addition to level crossings, this type of signalling can also be found at entrances to movable bridges, ferry pontoons, fire-service vehicle exits, or in areas where aircraft may approach at low altitude. Need to stop and wait: When they see these flashing red lights, drivers must stop and wait until the signal changes and the crossing is clear and it is safe to continue.