wine glassResearchers investigated how binge drinking affected the perceived driving ability of drivers.

According to Cecile A. Marczinski, assistant professor in the department of psychology at Northern Kentucky University and first author of this study, 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 study conducted among college students found that binge drinkers, even when legally intoxicated, nonetheless believed that they had adequate driving abilities.i She explained "Binge drinkers are often young individuals, like college students, who are drinking irresponsibly and most of them are not alcohol dependent … [but] when they drink, they typically drink to get drunk … College students, as a population, are most likely to binge drink."

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 which was below 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."

"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 being too drunk to drive safely feels like”.

i Effects of Alcohol on Simulated Driving and Perceived Driving Impairment in Binge Drinkers. Alcoholism: Clinical & Experimental Research. Emily L.R. Harrison of the Department of Psychiatry at Yale University; and Mark T. Fillmore of the Department of Psychology at the University of Kentucky. July 2008.