Rear-End Collision Velocity Reduction System

In Japan, rear-end collisions occur at higher frequency than many other kinds of traffic accident. The causes of rear-end collisions were therefore investigated. Accident statistics was used to conduct a statistical traffic accident analysis and a questionnaire survey was used to conduct a detailed traffic accident analysis. Simulation was then used to perform an accident analysis on the basis of those studies. The results suggested that many of these accidents were caused by momentary inattention during daily driving. Research was therefore carried out to determine what kind of collision avoidance assist system would be effective for use at such times. Tests were carried out to measure the obstacle avoidance characteristics of drivers using actual cars, and control timing parameters were established. In this process, the warning timing was set so that it would not lose its impact as a warning and also so that it would not interfere with the driver. The system was configured to make up for delays in recognition and judgment by means of brake control. The method of brake operation to be used was studied using both computation and testing with actual vehicle. The brake operation timing was set not to interfere with ordinary driver operations, and the deceleration was set to assist the driver’s avoidance maneuvers. The result was creation of a system capable of contributing to the reduction of rear-end collisions.