Weight reductions in passenger cars, lighter vans, pickup trucks, and sport utility vehicles (SUVs) increased the risk of fatal crash involvement, a study by the U.S. Department of Transportation's National Highway Traffic Safety Administration (NHTSA) has concluded. The study of 1991-99 models also found that large four-door passenger cars and minivans had the lowest fatality rates of all vehicle types.
The study, done on the recommendation of the National Academy of Sciences, found that:
Modest (100-pound) weight reductions in heavier (3,850 to 5,000 lbs.) light trucks and vans (LTVs) had little net effect on crash fatalities.
Modest weight reductions in the heaviest LTVs (greater than 5,000 lbs.) were associated with a reduction in fatalities in other vehicles.
One hundred-pound weight reductions in lighter LTVs and most passenger cars significantly increased fatality risk.
Large 4-door passenger cars had the lowest fatal crash rates followed closely by minivans. The highest fatal crash rate was observed in small 4-door cars, mid-sized SUVs and compact pickup trucks.
Two factors accounted for the difference in fatal crash rates between large passenger cars (average weight 3,596 lbs.) and mid-sized SUVs (average weight 4,022 lbs.). Mid-sized SUVs were nine times as likely to involve a rollover fatality and twice as likely to cause a fatality in occupants of other vehicles. In non-rollover crashes, the fatality rate for the occupants of SUVs and passenger cars of similar weight was essentially equal.
The study examined fatality data from 1995-2000 involving 1991-1999 model vehicles. Researchers adjusted the data to account for differences in driver age and gender, rural versus urban driving and other variables such as nighttime driving.
