What safety feature helps children cross safely in front of a school bus?

The stop sign arm with flashing lights is designed specifically to enhance the safety of children as they cross in front of a school bus. When a bus is stopped to pick up or drop off students, the stop sign arm extends outward, and its accompanying flashing lights are activated to alert drivers that they must stop. This visual signal is crucial as it ensures that vehicles approaching from both directions understand that they must yield to children who may be crossing the street.

In contrast, while rearview mirrors, emergency brake systems, and side-view cameras are important safety features for vehicle operation and accident prevention, they do not directly impact the safety of children crossing in front of a stopped bus like the stop sign arm does. The primary function of the stop sign arm with lights is to create a protective zone for children, significantly reducing the risk of accidents during school bus stops.