Effects of alcohol on simulated driving and perceived driving impairment in binge drinkers

Background:  Binge drinking (heavy episodic alcohol use) is associated with high rates of impaired driving and myriad alcohol-related accidents. However, the underlying reasons for the heightened accident risk in this demographic group are not known. This research examined acute alcohol effects on simulated driving performance and subjective ratings of intoxication and driving ability in binge and nonbinge drinkers.
Methods:  Young social drinking college students (24 binge drinkers and 16 nonbinge drinkers) participated in this study. Participants attended a session during which they received a moderate dose of alcohol (0.65 g/kg) and a session during which they received a placebo. A simulated driving task measured participants' driving performance in response to each dose. Subjective responses to each dose were also assessed, including ratings of sedation, stimulation, and driving ability.
Results:  The acute dose of alcohol impaired multiple aspects of driving performance in both binge and nonbinge drinkers. Under alcohol, all participants had greater difficulty in maintaining their lane position, maintaining the appropriate speed and made multiple driving errors compared to placebo performance. By contrast, compared with nonbinge drinkers, binge drinkers reported feeling less sedated by the alcohol and reported having a greater ability to drive following the acute dose of alcohol.
Conclusions:  Reduced subjective intoxication and perceived driving impairment in binge drinkers may account for the greater accident risk in this demographic group. Binge drinkers may lack the internal sedation cue that helps them accurately assess that they are not able to effectively drive a vehicle after drinking.