What must you do when a school bus has its red warning lights flashing and stop signal arm extended?

When a school bus has its red warning lights flashing and the stop signal arm extended, the law requires drivers to stop their vehicles regardless of the direction they are approaching from. This is to ensure the safety of children who may be crossing the street or getting on or off the bus.

Stopping before meeting or overtaking the bus is crucial because children can be unpredictable and may suddenly run out from in front of or behind the bus. Even if a driver is approaching the bus from the rear, they must still stop to avoid endangering any children who might be crossing.

Additionally, driving cautiously at the posted speed is important because it reflects the need for heightened awareness in areas where children may be present. However, the primary rule is that you must stop for the bus when its lights are flashing and the stop signal is extended.

Therefore, the understanding that a driver must stop in all situations when faced with a school bus displaying these signals forms the basis for the correct answer, which encompasses all the conditions mentioned.