This standard establishes requirements for the return of a vehicle??s throttle to the idle position when the driver removes the actuating force from the accelerator control@ or in the event of a severance or disconnection in the accelerator control system. Purpose. The purpose of this standard is to reduce deaths and injuries resulting from engine overspeed caused by malfunctions in the accelerator control system. Application. This standard applies to passenger cars@ multi-purpose passenger vehicles@ trucks@ and buses.