Abstract: The invention provides an accessory for a vehicle, the accessory having a sensor for sensing the acceleration of the vehicle, the speed of the vehicle or the operating speed of an engine of the vehicle, a first recorder for recording when any of these parameters is excessive, detectors for detecting whether the vehicle is in motion or the engine is in operation and a second recorder for recording the amount of time the vehicle is in motion or the engine is in operation. The accessory is electrically operable, the speed of the vehicle and of the engine being sensed by electro-magnetic devices in co-operation with magnetized elements whose speed of rotation is proportional to the speed of the vehicle or its engine. Conveniently, the acceleration of the vehicle is determined by differentiating a signal representative of the vehicle's speed. The accessory further includes a visual or aural alarm for warning a driver of the vehicle that an abuse condition has occurred or is about to occur.