Abstract: A device and method for automatically lowering the bed of a dump truck by disengaging the hydraulic pump and the power take-off when the transmission of the dump truck is shifted to or above a predetermined gear. A conventional dump truck or transmission system is utilized.

Abstract: The parking brake of a vehicle is automatically operated whenever the driver or operator leaves the operator's seat and/or opens the door to the vehicle. A seat switch and a separate door switch are electrically wired to an electrical solenoid which operates a valve that controls the supply of air from an air tank through a manual air valve to the brakes. The seat and door switches are connected in parallel to the ignition switch wired to the battery which is grounded to a common ground with the solenoid, whereby either the seat switch or the door switch be closed to release the brakes.