Abstract
To provide a warning when the driver is travelling dangerously close to a preceding vehicle, the vehicle distance warning system using a laser radar has been studied. A safe and effective system was achieved without invoking excessive driver's tension by determining the warning timing using the driver's sense of distance and the physical conditions. In addition an automatic shift-down control used to obtain engine brake force can be applied under more critical circumstances. As the next step the authors have studied a safety distance control method by recognising preceding vehicles and lanes by the laser radar and computer vision.