What action should be taken before engaging in traffic after stopping at a bus stop?

The action of accounting for all students before engaging in traffic after stopping at a bus stop is crucial for ensuring safety. This step involves assessing the area for children who may be boarding or alighting from the bus. Young students can be unpredictable and may approach the bus from various directions. By taking the time to confirm that no children are in the immediate vicinity, a driver can significantly reduce the risk of accidents.

Checking mirrors is indeed important for overall situational awareness, but it comes after confirming that all students are accounted for. Similarly, turning on a left turn signal or turning off flashing red lights are relevant actions, but they should only be considered once it's safe to do so. Therefore, the priority must be ensuring the safety of students first and foremost.