Both studies, conducted by the Washington-based AAA Foundation for Traffic Safety, evaluated habitual offenders. In one, researchers found that unlicensed drivers are five times more likely to be in fatal crashes than drivers with valid licenses.
The other study found that 40 percent of all drunken driving trips are made by habitual drunken drivers, and that more than half of all arrested drunken drivers are repeat offenders.
Foundation President Susan Pikrallidas said states need to reevaluate and improve enforcement of measures meant to keep habitual offenders off the road. For example, the study of unlicensed drivers found that two-thirds of drivers with suspended licenses continue to drive.
Pikrallidas also said states are doing a poor job of identifying chronic drinkers, who often return to the roadways untreated. The foundation's study found that there was only a 1 in 50 chance that a drunken driver would actually be arrested.
The drunken driving study also found that two-thirds of fatally injured drivers have alcohol levels twice the legal limit. According to the National Highway Traffic Safety Administration, 17,448 people were killed in alcohol-related crashes in 2001, accounting for 41 percent of all U.S. traffic deaths.
Pikrallidas said the AAA Foundation will use the studies to push for continued federal support for traffic safety programs at the state and local level.