While they're more prone to roll over during accidents than cars, newer sport utility vehicles now have a lower overall death rate, according to a study by an insurance industry research group, the Chicago Tribune reports. But the statistics also support a frequent criticism of SUVs: Their size and weight cause mismatches in collisions with smaller vehicles, and those occupants are more likely to be killed or injured, the Tribune said. An analysis of 2001 traffic deaths by the Insurance Institute for Highway Safety shows the death rate in SUVs fell to 115 fatalities per million registered vehicles, the lowest among all types of passenger vehicles. That was down from 134 fatalities per million in 2000 and from 494 per million in 1980, when SUVs accounted for twice the number of fatalities as cars, the Tribune reported.