Abstract: In a device on a motor vehicle having a brake and brake operating element, a drive assembly and a drive power source with an automatic transmission, a power control element for the drive power source, and a selector mechanism for shifting the automatic transmission from a neutral position and/or a park position into one or more forward or reverse drive positions, means acting on the drive power source and/or the power control element are provided, which means are connected to the brake operating element and the selector mechanism and which disable power output from the drive power source on engagement of a drive position from the N and/or P position unless the brake of the vehicle has been applied.