Binge drinking and driving

May 11 2008

While many people believe that alcohol-impaired (AI) drivers are usually alcoholics, in fact, 80 percent of AI incidents are caused by binge drinkers. A recent study conducted among college students has found that binge drinkers, even when legally intoxicated, nonetheless believe they having adequate driving abilities.

Results will be published in the July issue of Alcoholism: Clinical & Experimental Research and are currently available at OnlineEarly.

"Binge drinkers are individuals who, when they drink, typically drink to get drunk," explained Cecile A. Marczinski, assistant professor in the department of psychology at Northern Kentucky University and first author of the study. "Binge drinkers are often young individuals, like college students, who are drinking irresponsibly and most of them are not alcohol dependent."

College students, as a population, are most likely to binge drink, Marczinski added. "Binge drinking is widespread on college campuses, with almost half of students reporting binge drinking," she said. "They are also particularly prone to AI driving. Thus, we needed to understand why a population that knows better than to engage in impaired driving still does.

Participants in this study were 20 male and 20 female social-drinking college students (24 binge drinkers, 16 non-binge drinkers) between 21 and 29 years of age. All participants attended two sessions: one during which they received a moderate dose of alcohol (0.65 g/kg), and one during which they received a placebo. Following each session/dose, researchers measured the students' performance during a simulated driving task, and also measured their subjective responses, including ratings of sedation, stimulation and driving abilities.

"After being given an intoxicating dose of alcohol, all of these individuals - both binge and non-binge drinkers - were very poor drivers when tested on a driving simulator," said Marczinski. "However, when all of the participants are asked to rate their driving ability, the binge drinkers reported that they had a greater ability to drive compared to the non-binge drinkers."

The authors hypothesize that binge drinkers lack an "internal sedation cue" that allows an accurate assessment of their driving abilities after drinking.

"Furthermore," said Marczinski, "the dose of alcohol we gave resulted in a blood alcohol concentration (BAC) of .08g percent, which is the legal limit for driving. If these binge drinkers had been driving and were stopped by police, they would have been prosecuted for impaired driving."

Marczinski said that these findings might help policy and law makers understand why the standard message of "don't drive when your BAC reaches .08 or more" may be not be as straight forward to follow as one might think.

"A BAC of .08 may feel differently depending on how much you typically drink," she said. "If you often drink to get drunk, as many young people do, you will be very bad at determining whether or not you should drive. Thus, prevention programs where college students are stopped leaving bars and given a breathalyzer reading may help many individuals learn what .08 feels like. In addition, we might also entertain a lower BAC limit for driving. Many European countries have had great success in decreasing impaired driving rates and related accidents by lowering their BAC limit to .05."

There is some good news, however. "While a small portion of young binge drinkers may develop serious problems with alcohol, most of them will mature out of this behavior," she said.