An apparatus includes an inter-vehicle distance sensor for measuring a distance from a self vehicle to a vehicle traveling ahead, and a relative speed is calculated on the basis of the inter-vehicle distance data detected by the inter-vehicle distance sensor. When a variation of the relative speed is...http://www.google.de/patents/US5396426?utm_source=gb-gplus-sharePatent US5396426 - Constant speed traveling apparatus for vehicle with inter-vehicle distance adjustment function
