Abstract
This paper presents the concept and design of a real time measurement system of the distance between vehicles, in order to prevent rear crash accidents and in particular serial crashes. Statistic shows that about 20% of the police-reported crashes are rear-end. The proposed system contains a distance detection device on the back side of the vehicle, to measure the distance to the following car and its velocity, and a computing unit which compares this distance with the "safe" one, calculated as a function of speeds, accelerations, load and the road surface conditions. If the former distance is below the latter one, a bright warning is displayed on the rear side of the vehicle by the system, indicating to the following driver that in case of an emergency braking situation he is in danger of crashing into the vehicle preceding him.