Abstract: The present invention relates to a device ascertaining that a vehicle does not exceed a pre-set speed limit and/or a pre-set engine RPM limit. Said device comprises means for transferring the input movement from the accelerator to means for contacting the output movement; means for transferring said output movement to the speed control unit; electrical means actuating said control means at the proper time, means for reading the speed and/or the engine RPM and means for pre-setting the desired speed limit and/or engine RPM limit. Said device may comprise additional means for protecting the vehicle to be driven by unauthorized persons. The device may be utilized for any vehicle and/or machine which is actuated by a lever and the drawing distance together with the load determine the speed, e.g., cars, airplanes, tractors and other agricultural implements.