This paper presents a safety design of a micro computer based motor controller for joystick car drive systems The controller controls an angle of an electric motor so that an angle of a steering wheel or that of gas/brake pedals are operated to maneuver and drive vehicles However, a wrong joystick operation, such as a sudden and wide steering, when a vehicle running in a very high speed results in a car accident quite easily To avoid this kind of accidents, we propose a steering control method with variable steering sensitivity and steering restriction based on a vehicle velocity Addition to the steering control, system errors such as disconnection of wires and devices can be detected by the controller