What action should be taken if a school bus driver encounters a railroad crossing?

When a school bus driver approaches a railroad crossing, the most critical action is to stop and look both ways before crossing. This precaution is vital for ensuring the safety of the children on the bus and the driver themselves. By stopping, the driver can visually check for any approaching trains, which could be difficult to hear, especially in a noisy environment or if there are distractions in the bus. This practice helps to prevent dangerous situations where a train might be present but not immediately visible.

The other choices present actions that could potentially put the safety of the bus passengers at risk. Rushing through the crossing without stopping ignores the possibility of a train approaching, which is a significant hazard. Relying on a supervisor for instructions could lead to delays or inappropriate responses in urgent situations. Lastly, crossing only when the lights are flashing is important but doesn't cover scenarios where the lights may not be operational. Thus, the best practice remains to stop and look both ways, ensuring comprehensive awareness of the surrounding environment.