Alcohol, Time of Day, and Driving Experience: Effects on Simulated Driving Performance and Subjective Mood

The effects of alcohol on driving were examined as a function of time of day and driving experience. 28 volunteers operated a driving simulator for 90 min at 6 testing sessions. Participants attended 2 sessions at 12:00 p.m., 6:00 p.m., and 11:00 p.m., after consuming either 0.70 ml/kg alcohol or juice only. Driving performance and secondary reaction time were significantly impaired after alcohol consumption at all times of day. Levels of driving skill were highest at 11:00 p.m., despite the highest levels of subjective sleepiness and low motivation at this time. Both the practical and theoretical implications of these results are discussed.