What must a driver do when a school bus is loading or unloading passengers?

When a school bus is loading or unloading passengers, a driver must activate hazard lights and monitor the surroundings closely to ensure the safety of the children getting on and off the bus. The use of hazard lights serves as a visual warning to other drivers, indicating that there is a stop in progress and that they should approach the area with caution.

Additionally, monitoring the surroundings is crucial for identifying any unexpected hazards, such as children running or moving in unpredictable ways. This proactive approach helps prevent accidents by ensuring that the driver remains aware of the environment and can react accordingly.

The other choices do not provide the necessary safety measures that are essential when a school bus is loading or unloading. Driving slowly past the bus does not communicate to others that a stop is occurring and may not account for the movements of children. Checking mirrors alone may not capture all potential dangers around the bus. Sounding the horn could alarm other drivers but does not directly improve safety for the children involved.