Highway Safety

Smaller cars, the argument goes, are less safe than larger cars, and the automobile fatality rate will therefore increase if more small cars appear on America's roadways. This projection about the negative consequences of future auto downsizing derives from research on the effects of past auto weight reductions among specific makes and models of cars or in particular types of accidents. This research has focused on "crashworthiness"--that is, the protection that cars of different sizes afford their occupants in a collision. GAO reviewed the literature on auto weight and safety and did its own analysis from fatal traffic accident data compiled by the National Highway Traffic Safety Administration. GAO's findings support the view that the auto weight reductions since the mid-1970s have had virtually no effect on total highway fatalities. Fatality rates for all cars have declined in recent years, but the rate for light cars has improved more than for heavier cars. GAO found that an approach that focuses exclusively on crashworthiness neglects other important factors involved in the weight/safety relationship that may have had beneficial effects on highway safety during the 1970s and 1980s. One of these factors is the dramatic reduction in the number of heavy cars and therefore in the danger that these cars pose to occupants of other vehicles with which they collide.

GAO found that: (1) the increase in the proportion of light cars on the road has had virtually no effect on total highway fatalities; (2) between fiscal year (FY) 1975 and FY 1988, the median weight of passenger cars on American roads decreased by approximately 28 percent; (3) between FY 1975 and FY 1988, overall automobile occupant fatality rates declined by more than 20 percent; (4) the very lightest cars, those weighing 1,800 pounds or less, had substantially higher occupant fatality rates than those above 1,800 pounds; (5) fatality rates for all weight categories were substantially higher in the 1970's than in the 1980's; (6) the largest cars had the lowest occupant fatality rates; (7) it is likely that some proportion of the fatalities in lighter car categories could be attributed to driver age rather than to automobile weight, since young drivers are involved disproportionately in fatal accidents and drivers under 25 years of age are much more likely to operate lighter cars; and (8) cars in the middle of the weight distribution scale had higher fatality rates than cars in some lower weight categories.