One of the ways the National Highway Traffic Safety Administration quantifies the benefits of seat belts and frontal air bags is to estimate the number of passenger vehicle occupants whose lives were saved by these protective devices, and the lives savable if more passenger vehicle occupants had buckled up. Passenger vehicles include passenger cars, sport utility vehicles, pickup trucks, and vans. This report details how NHTSA produces these lives saved estimates for seat belts and frontal air bags. The methodology is described in detail, including the use of effectiveness ratings for seat belts and frontal air bags. Seat belt effectiveness ratings vary according to the seat belt type (i.e., 3-point belt versus 2-point lap belt), vehicle type, occupant seating position, and occupant age. Frontal air bag effectiveness ratings are consistent for all passenger vehicles. The interactions of the effectiveness of seat belts and the effectiveness of frontal air bags are discussed in this report. The effectiveness of side air bags, child safety seats, motorcycle helmets, and other safety devices are discussed in other NHTSA reports, and are not quantified within this report. When calculating lives saved by seat belts and air bags, it is important to remember that these calculations are estimates based on a methodology that uses the tremendous amount of knowledge that National Highway Traffic Safety Administration has gained. This knowledge has been expanded through the analysis of decades of data on the roles played by seat belts and air bags in fatal crashes. (Author/publisher)
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