Which condition indicates a motorist is violating the school bus stop law?

A motorist is violating the school bus stop law when the bus is displaying its mechanical stop signal. This signal is a critical safety feature designed to protect children boarding and disembarking from the bus. When the stop signal is extended, it visually indicates to all surrounding motorists that they must come to a complete stop, regardless of which direction they are coming from.

When a school bus is in motion, this does not indicate any violation of the stop law, as the focus is specifically on the moment when children are loading or unloading. If the bus is parked without passengers, there is no requirement for other vehicles to stop. Indeed, a bus moving at a constant speed similarly does not indicate any violation because it is not currently engaged in the process of dropping off or picking up children. However, when the mechanical stop signal is active, it requires all drivers to adhere to the traffic laws designed to ensure the safety of children around school buses.