This small car accident study investigated accidents in Washington State in four passenger car categories: subcompact, compact, intermediate, and large. The primary purpose of the study was to evaluate the effects on safety of increases in the number of smaller cars on the highways. Traffic accident data for the period 1973-79 were analyzed to determine the accident severity for the different automobile classes, and this analysis showed that the smaller vehicles had a higher proportion of fatal and injury accidents that the other categories.
Then, accident data for 1980 were used to compare accident experience with regard to injury class of the occupants, roadway surface conditions, roadway character, light conditions, collision type, objects struck, and location of accident. Analysis showed that for total accidents per one thousand registered vehicles, the large cars had a higher rate (68) than either the subcompacts (43), compacts (45), or intermediate size vehicles (46). However, the subcompacts and compacts had higher percentages of fatalities and serious injuries to their occupants, and a higher proportion of such accidents occurred on wet, snowy, and icy surfaces. In addition, the smaller passenger vehicles had a higher incidence of overturning and rear-end accidents. The analysis suggests there will be significant increases in fatal and injury accidents in future years as the number of smaller vehicles increases. Thus, the report contains recommendations for changes in highway and vehicle design that will modify these adverse trends and reduce injuries and fatalities among drivers and passengers.
Some of the recommendations can be implemented fairly quickly, but others will take longer. However, until changes are made, the accident severity for small cars will continue at a level above that for larger automobiles.