In many locations, seat belt usage of vehicle occupants is about 80% to 90%, the proportion of fatalities who did not wear a belt is about 50%. This suggests that a vehicle occupant has almost six times as high a death risk as one who is wearing a belt. Japanese accident statistics contain much interesting information, even though they use many variables that Europeans find hard to define. Seat belt usage is recorded for every injured vehicle occupant reported to the police. During 1998, almost 4000 car occupants were killed, and about 600,000 injured. 0.68% of the injured drivers died, compared with 2.4% in Sweden, and 0.58% of the injured passengers died, compared with 2.2% in Sweden. 90% of the drivers, 80% of the front-seat passengers, and 20% of the rear-seat passengers in the accidents used a seat belt; the proportions were lower among younger and older people. This article gives a simple model of the effects of wearing or not weariing seat belts on casualties. The Japanese statistics verify the model. Denmark is another country where full information is usually collected on seat belt usage among those involved in car accidents. In Denmark, the death risks are highest for unbelted drivers and for older drivers, and the effect of a seat belt on safety increases with lower age. Belt usage is less effective for passengers.
Abstract