Reflex measuring apparatus for determining the reactivity of a driver, or respectively, his ability to drive a vehicle under conditions including under the influence of alcohol or drugs, tiredness, stress or normal effects of age. Reflex measuring apparatus includes s a steering wheel of a vehicle that acts as a sensor for measuring the reaction time span of the driver, a signaling device soliciting the reaction of the driver, a device to record a time span between the solicitation by the signaling device and a reaction of the driver (e.g. an analogue or digital chronograph), and a seat provided with a safety belt. The apparatus can be activated when a driver takes place on the seat.
