Alcohol hangover induced decrements in simulated driving performance during a short commute towork

Purpose: There have been relatively few studies investigating the effect of alcohol hangover on driving performance next day when participants are experiencing a hangover following evening alcohol consumption. Although drivers may be able to briefly compensate for a known impairment (Verster and Roth 2012), the effects on a typical 'commute to work' in a demanding environment requires investigation. Methods: Thirty-five participants (Age range 18-23, mixed sex group) who were driving license holders underwent a 20 min drive with a speed limit set to 50 mph and including a mixed urban and rural environment which included hazards (e.g. pedestrian stepping into the road), and concomitant divided attention task (spotting change between triangle/diamond peripheral stimuli) with the STISIM driving simulator. A pseudo-random allocation to treatment order was employed (hangover/no-hangover), with measures including STISIMdriving performance variables together with mood (Bond and Lader VAS), subjective hangover (Penning Hangover rating scale) and perceived workload (NASA TLX). Results: Hangover was substantiated by hangover ratings (e.g. fatigue, apathy, poor concentration, confusion, clumsiness, thirst). Significant findings (p <0.05) reflecting impaired vehicle control included increased speed, and reaction time to peripheral stimuli in the hangover condition. Possible lapses were shown with doubling the number of lane excursions and increased time spent over the centre line. Separate analyses of participants with residual alcohol (N = 14,mean BAC <0.05%) compared to zero residual alcohol (N = 21) provided significant contrasts for mean speed,%time across centre line,%off road, accidents & crashes as well as lane excursions demonstrating a clear difference between these groups. Four of 6 subjective workload parameters were significantly increased with hangover reflecting greater effort and increasedmental demands. Conclusion: Whilst driving impairment with alcohol hangover has been reported during a simulated 1 h highway drive (Verster et al 2014), the significant impairments seen here, after a relatively short driving duration reflecting a typical commute to work represents a new finding. The results suggest that in a demanding driving environment even shorter driving periods are detrimentally affected, and that drivers were unable to compensate despite increased subjective effort. Residual alcohol had a marked impact on some variables though below legal limit. These findings could be incorporated into driver safety campaigns.