Using the consolidated 9-year traffic accident database from 1995 through 2003, the number of drivers who met accidents while wearing seat belts were studied by the degree of injury, and by cars "equipped with air bags", "not equipped with air bags", and "not confirmed". "Not confirmed" means that, although the car is of a type that accommodates air bags, it was not confirmed whether the car actually had an air bag. Table 1 shows the result, indicating that a total of 466,481 drivers fitted the description.   The accidents numbered some 200,000. Since almost all accidents involved two parties, approximately half the total number of victims indicated above was the number of accidents. The expression "almost all accidents involved two parties" is used here because, if a person involved in an accident was in an ordinary cargo carrier, the driver of that carrier is not counted.   The figures below suggest that more deaths occurred in cars with air bags than in cars without: 14 vs. 11. But this is due to the difference in the number of accidents in each category.

A comparison of component ratios by the presence or absence of air bags and by the degree of injury suffered by victims is shown in Chart 1. "No injury" accounted for a significant 96.2% among drivers of cars with air bags. The percentages of those slightly injured (3.4%), seriously injured (0.3%), and killed (0.01%) were low compared with other categories.

The degree of driver's injury depends not only on the presence or absence of an air bag, but also on the speed of vehicle impact, object against which the car collided, and age of the driver, among many other factors. Eliminating those factors, the number of deaths and serious injuries was calculated to have been 2,001 (Table 2).   Next, the number of drivers fatally or seriously injured was estimated if air bags had been absent in cars with air bags, and cars in which the presence of air bags was not confirmed.   Table 2 shows that the number of drivers fatally or seriously injured would have been 20.9% greater if cars with air bags had not been equipped with them, and 17.7% greater if unconfirmed cars had no air bags.   As a result, it is calculated that drivers fatally or seriously injured would have increased by 330 people (16.5%) if these cars had not been equipped with air bags.

The backdrop of the reduction in injuries thanks to air bags was analyzed from the viewpoint of injured body parts.   Fatally and seriously injured drivers were divided by the part of the body primarily injured, as shown below: head, neck, chest and abdomen, arms, hips and legs, and others. Chart 2 compares the result with the presence or absence of air bags.   "Entire body" in the legend of Chart 2 indicates that it was impossible to specify the part damaged. Among cars equipped with air bags, head injury accounted for 8.3%, significantly smaller than other cases. It can be concluded that fewer head injuries contributed to the small percentage of the fatally or seriously injured.

UP

Institute for Traffic Accident Research and Data Analysis (ITARDA)