This International Standard specifies performance requirements and test procedures for systems capable of warning the driver of a potential rear-end collision with other vehicles ahead of the subject vehicle while it is operating at ordinary speed. The FVCWS operate in specified subject vehicle speed range, road curvature range and target vehicle types. This International Standard covers operations on roads with curve radii over 125 m, and motor vehicle including cars, trucks, buses, and motorcycles. Responsibility for the safe operation of the vehicle remains with the driver.