When is it necessary to stop for a school bus?

Stopping for a school bus is a critical safety measure designed to protect children as they enter or exit the bus. The law requires drivers to stop when the bus has its lights flashing and the stop sign is extended. This indicates that children may be getting on or off the bus, and it is essential to ensure their safety by allowing them to cross the street without the risk of oncoming traffic.

In situations where the bus is unloading children, as indicated in the correct answer, vehicles approaching from both directions must stop to create a safe environment. Ignoring these signals could lead to severe consequences, not only for the children but also for the driver, who may face legal penalties.

Other scenarios presented do not adequately capture the requirements for stopping. For example, stopping only when loading or unloading children would not account for situations where children may be crossing the street even when the doors of the bus are closed. Additionally, merely being near a crosswalk doesn't trigger the need to stop for a school bus, and stopping only when children are present disregards the fact that they may be moving to or from the roadway at any time within the bus's range of influence. Thus, understanding the correct signage and their meanings is crucial for ensuring the safety of young pedestrians.