Motor vehicle accidents are a common cause of death for all age groups but are the most serious threat to life for patients aged one to 34 years. Major progress has been made in reducing these losses through improved highway design, improved laws, adjudication of laws controlling the drunk driver, and the advent of vehicle safety design standards. A federal law enacted in 1966 established the National Highway Traffic Safety Administration (NHTSA) and the Federal Motor Vehicle Safety Standards (FMVSS). Motor vehicles, particularly passenger cars, now provide effective protection for occupants because of vehicle safety design features required by the FMVSS. Safety belts are the single most effective safety device available and are required equipment in virtually all motor vehicles sold in the United States. Passive protection for nonusers of safety belts is rapidly improving with the availability of air bags and automatic belt systems, improved windshields, steering wheels, dashboards, and seats, and other vehicle crashworthiness features. Motorcyclists, bicyclists, and pedestrians are also provided with improved protection because of the FMVSS.