The aim of this study is to evaluate driving impairment linked to divided attention task and alcohol and determinate if it is higher for novice drivers compared to more experienced drivers. Sixteen novice drivers and sixteen experienced drivers participated in three experimental sessions corresponding to blood alcohol concentration [BAC] of 0.0 g/L, 0.2 g/L and 0.5 g/L. They performed a divided attention task [car-following task combined with a number parity identification task], and their results were compared to baselines obtained in reference single-tasks. Driving performance was evaluated by standard deviation of lateral position and minimum inter-vehicular distance. Response time and accuracy on additional task were also measured. Overall, ANOVA showed a driving impairment from BAC of 0.5 g/L with an increase of lateral position variability and a decrease of correct response percentage. In addition, novice drivers seem to be particularly disrupted by negative impact of alcohol because they adopt more risky behavior as to tailgate the vehicle in front of them. In divided attention task, driving impairment was found for all drivers. With respect to accuracy, information processing impairment was highlighted, notably in peripheral vision. Results are interpreted in terms of limited information processing capacity. Thus, the divided attention task used here provides a relevant method to isolate and identify effects of acute alcohol intoxication on cognitive functions and could be used in psychopharmacological research.
