Effect of car size on the frequency and severity of rollover crashes.

Narrower, lighter, shorter cars have higher rollover rates than wide, heavy, long ones under the same crash conditions. During model years 1970-82, as the market shifted from large domestic cars to downsized, subcompact or imported cars, the fleet became more rollover prone. The net effect of all car size changes since 1970 is an increase of approximately 1340 rollover fatalities per year in the United States. The methods of this report do not identify which individual vehicle size parameter (track width, curb weight, wheelbase, etcera) is the principal "cause" of rollover proneness. (A)