The analysis of a rear-end collision warning/avoidance (CW/CA) system algorithm will be presented. The system is designed to meet several criteria: 1.System warnings should result in a minimum load on driver attention. 2.Automatic control of the brakes should not interfere with normal driving operation. 3.The system should perform well in a variety of driving conditions. The resulting CA algorithm will use a tire-road friction estimate. The benefit of combining a tire-road friction estimator with a CA system will be studied.