What does the engine over-ride function do?

The engine over-ride function plays a critical role in maintaining safety during a situation where there is a potential engine failure. Specifically, this function allows the bus operator to control the vehicle and maneuver it to a safe location, rather than stopping abruptly, which could pose a danger to both the passengers and other motorists on the road. This feature is designed to ensure that the bus can be brought to a stop in a controlled manner, minimizing the risk of accidents and maintaining safety standards on the roadway.

In contrast, the other options present functionalities that do not align with the purpose of the engine over-ride function. Activating the air conditioning is unrelated to engine performance; changing the bus speed limit does not pertain to managing engine failure; and turning off the engine completely would not help in reaching a safe location but instead would stop the vehicle instantly, which could be hazardous in the event of engine issues.