Simulated Driving Performance Under Alcohol: Effects on Driver-risk Versus Driver-skill

Background: Those who place their vehicles closer to others on the roadway are said to have high risk acceptance, and this contributes to motor vehicle crashes. However, the effect of alcohol on this risky driving behavior is understudied. Behavioral mechanisms that contribute to risky driving are also not well understood. Further, whether increased risk-taking behavior in a driver co-occurs with pronounced impairment in the driver's skill is unknown.

Methods: The study examined the effect of alcohol on driver risk and skill and whether riskier drivers were also those who showed high skill impairment. The relationship between driving behavior and inhibitory control was also tested. Participants completed two driving simulations. In the first drive test, risky driving was encouraged and in the second test, skill-based performance was emphasized. The cued go/no-go task provided a measure inhibitory control. Tests were completed under a 0.65g/kg alcohol and 0.0g/kg (placebo) dose of alcohol.

Results: Alcohol impaired a measure of driving skill and increased driver risk taking. It was also found that riskier drivers were not necessarily those who showed the greatest impairments in skill. Poorer inhibitory control was associated with greater driver risk in the sober state.

Conclusions: Alcohol-induced risk-taking behaviors can be dissociable from impairing effects on driver skill and poor inhibitory control is selectively related to risky driving. As such, a distinction between driver risk and driver skill needs to be made in the investigation of problems concerning DUI-related accidents and fatalities in future research.