Automatic seat belts are presented as a method of complying with proposed government regulations requiring passive protection against occupant injury from vehicle collisions. Operational models have been installed in current model cars. The proven field performance of belt systems now in cars reducing fatalities and injuries is the fundamental basis for considering the automatic seat belt.Several design approaches for automatic seat belts are explored and described. Webbing and hardware modifications to adapt the configuration of the belt systems to present car interiors are described in detail. Dynamic testing results are presented to compare crash performance to current production belt systems now in cars.