California CHP School Bus Practice Test

Taking the key from the ignition is critical before leaving the bus unattended because it prevents unauthorized use of the vehicle. Leaving the keys in the ignition can pose significant safety risks, such as the bus being moved by a child or unauthorized person. This action is part of ensuring that the bus is secure and that no one can accidentally or intentionally drive it away.

In the context of other options, checking all mirrors is important for visibility and safety but does not directly relate to securing the vehicle when leaving it unattended. Notifying passengers to leave is relevant when you want to disembark them from the bus, while closing all windows helps maintain the bus's condition but is not as crucial as ensuring that the vehicle is not operable by others. Thus, the primary focus when leaving the bus is to ensure it is secure through actions like removing the key from the ignition.