When may drivers cross the tracks of an unguarded railroad crossing marked by a flashing light right after a train has passed?

The appropriate time for drivers to cross the tracks of an unguarded railroad crossing marked by a flashing light is when the flashing red light goes out. The flashing red lights serve as a warning signaling that a train is approaching, and it indicates that the area is not safe to cross.

Waiting for the flashing red light to extinguish ensures that any subsequent trains have also passed and that the crossing is clear. This precaution significantly lowers the risk of accidents, as trains can often follow closely behind one another, and the driver needs to ensure the track is completely clear before proceeding.

While it may seem logical to cross immediately after a train has passed, doing so without confirmation that the light has stopped flashing poses the danger of a second train being on the track. Likewise, simply checking for other vehicles or only considering the visibility of other trains does not effectively ensure safety, as the primary focus should always be on the operational status of the warning lights.