Which condition is NOT required for a motorist to be in violation of the school bus stop law?

The condition that the bus is stopped for maintenance does not contribute to a violation of the school bus stop law. The law is specifically designed to protect children when they are boarding or disembarking from a school bus. When a bus is displaying its mechanical stop signal and stopping to discharge passengers, or is visibly identified as a school bus, motorists are required to stop and yield to oncoming traffic. In contrast, maintenance activities do not involve the regular passenger stop protocols and thus do not invoke the same safety measures mandated by the law. Therefore, it's the presence of a mechanical stop signal, the act of discharging passengers, and the clear identification of the bus as a school bus that establish the conditions under which a violation can occur, not maintenance situations.