Background: The purpose of this study was to examine the effects of alcohol hangover on simulated highway driving performance.
Methods: Driving performance of forty-two social drinkers was tested the morning following an evening of consuming on average 10.2 (SD = 4.2) alcoholic drinks (alcohol hangover) and on a control day (no alcohol consumed). Subjects performed a standardized 100-km highway driving test in the STISIM driving simulator. In addition to the standard deviation of lateral position (SDLP; i.e., the weaving of the car), lapses of attention were examined. Self-reported driving quality and driving style were scored, as well as mental effort to perform the test, sleepiness before and after driving, and hangover severity.
Results: Driving performance was significantly impaired during alcohol hangover as expressed by an SDLP increase of +1.9 cm (t (1,41) = 2.851, p = 0.007), increased number of lapses relative to the control day (7.7 versus 5.3 lapses, t (1,41) = 2.125, p = 0.019), and an increased total lapse time (182.7 versus 127.3 s, p = 0.040). During alcohol hangover, subjects reported their driving quality to be significantly poorer (t (1,41) = 4.840, p = 0.001) and less safe (t (1,41) = 5.078, p = 0.001), wise (t (1,41) = 4.061, p = 0.001), predictable (t (1,41) = 3.475, p = 0.001), and responsible (t (1,41) = 4.122, p = 0.001). Subjects further reported being significantly more tense while driving (t (1,41) = 3.280, p = 0.002), and more effort was needed to perform the driving test (t (1,41) = 2.941, p = 0.001). There was a significant interaction with total sleep time and hangover effects on SDLP and the number of lapses.
Conclusions: In conclusion, driving is significantly impaired during alcohol hangover, as expressed in an elevated SDLP and increased number of lapses. Total sleep time has a significant impact on the magnitude of driving impairment.