Are low doses of alcohol taken at 2 pm objectively and subjectively more decrement for novices drivers than for more experienced drivers ?

Abstract

The objective was to evaluate subjective estimation and objective performance of drivers depending on Blood Alcohol Concentration (BAC) and driving experience. Assuming that during monotonous driving performance should be impaired with alcohol at a moment of alertness decrease, the hypothesis was that this impairment would be significant greater for Young Novice Drivers (YND) than for Young Experienced Drivers (YED). 16 YND (18 years, two months of driving) and 15 YED (21 years, 3 years of driving) participated in three simulated driving sessions in which BACs were randomly assigned (0.0, 0.2 and 0.5 g/L). Every session took place between 2 and 4 pm, around one hour after the drink. The circuit represented a typical highway road, the task was to drive during 45 min and to maintain a steady speed (110 Km/h) and a stable position on the lane. After each driving session participants estimated their workload (NASA-TLX questionnaire) and their subjective alertness (Thayer checklist). Driving performance was analysed for steps of 5 min. Globally, placebo session produced higher estimation of alertness, lower estimation of time pressure, physical demand, frustration and effort than BAC sessions. Driving performance was also worse with alcohol. A decrease of alertness and an increase of physical and mental effort were noted with the time-on-task. Thus, evaluation of alertness and effort during monotonous driving task were relatively well correlated with objective performance under the influence of alcohol and with time-on-task. YND had a lower subjective alertness level and estimate to have higher mental and physical workload than YED, their subjective performance and objective driving performance showed an effect of alcohol. YED performance and subjective evaluation are clearly sensitive to alcohol but also to time-on-task (combined effect)