Threat of jail time doesn't keep drunken drivers off the road

April 5, 2007

GAINESVILLE, Fla. — Actor Mel Gibson avoided jail time after he was convicted of driving under the influence in California last year. Most people who take to the wheel after drinking don’t think they’ll wind up behind bars either — or even be caught, as the “Braveheart” and “Lethal Weapon” star was, University of Florida researchers say.

Tougher mandatory minimum jail sentences for driving under the influence actually keep few drunken drivers off the road and don’t significantly prevent fatal car crashes related to drunken driving, according to a new study published last week in the online edition of the journal Accident Analysis and Prevention.

Researchers looked at changes in laws and policies regarding mandatory minimum fines and jail sentences for drunken driving between 1976 and 2002 and studied rates of DUI arrests and alcohol-related fatal car crashes. They wanted to find out if the stricter regulations deterred people from drunken driving and if the number of accidents dropped in the population as a whole, said Alexander C. Wagenaar, a professor of epidemiology in UF’s College of Medicine and the study’s lead author.

“We found out that’s not the case,” Wagenaar said. “The key thing for a deterrence law like this to work is people have to believe if they engage in the behavior that they’re actually going to experience the penalty. There are many in the general public who continue to drive after drinking because they don’t really believe that they’re going to be detected, pulled over, caught and go through the process to be convicted before a jail term would come into play.”

More than 16,000 people died as a result of alcohol-related accidents in 2005, according to the National Highway Traffic Safety Administration, and Department of Justice records show that more than 1.4 million people were arrested for driving under the influence of drugs or alcohol in the same year.

The UF study, which was funded by the Robert Wood Johnson Foundation, shows that tougher fines had a slight effect on drunken driving rates in some states, but there wasn’t a consistent pattern. For example, states with tougher fines didn’t always have a greater decrease in DUI arrests, Wagenaar said.

Of the 48 states researchers studied, 18 established mandatory minimum jail terms and 26 instituted mandatory minimum fines. Of the states that established minimum jail sentences for first-time offenders, five actually showed a significant decrease in fatal car accidents after the changes were made, the study shows. But two of those states established other DUI policies at the time, so it’s unknown whether jail time was actually a factor, Wagenaar said.

The researchers also compared the effects of new tougher laws on drivers involved in car accidents who were impaired at varying levels after 1982, when officials began testing blood-alcohol concentration levels. They separated the drivers into three groups: those whose blood-alcohol levels fell between .01 and .07, between .08 and .14, and .15 and beyond. The legal blood-alcohol limit in most states is .08. But the changing laws didn’t seem to have more effect on any particular group, Wagenaar said.

“People agree that drinking and driving is unacceptable,” said James C. Fell, director of traffic safety and enforcement programs for the Pacific Institute for Research and Evaluation in Maryland. “But they do it because they don’t get caught. On average statistics show that a person drives under the influence 50 to 200 times before they get caught or crash.”

Aside from the fact that most people don’t think they’ll get caught, Wagenaar said post-conviction penalties such as fines and jail time don’t happen fast enough for the consequence to be associated with the behavior in most people’s minds. Generally, it takes six months to one year before a person convicted of DUI goes through the courts and has to pay a fine or go to jail, Wagenaar said.

“We know from psychological research and research in other areas that for a consequence to influence behavior, that consequence needs to happen close to the behavior,” he said. “It’s the same thing we do when we’re disciplining our children.”

More enforcement, such as weekly checkpoints, is needed to make anti-drunken driving laws more effective, Fell said.

Although mandatory jail sentences don’t deter drunken drivers, Wagenaar said these findings shouldn’t be misconstrued that jail time isn’t useful as a punishment.

“It’s clearly appropriate for someone who has been convicted two or three times who is not changing their behavior,” Wagenaar said. “We get ultimately to a point where we have to take measures because they’re such a threat to society.”