Impairment of driving performance caused by sleep deprivation or alcohol: a comparative study

A study was conducted to assess the relative impact of partial sleep deprivation (restriction to 4 h sleep before testing) and full sleep deprivation (no sleep on the night before testing) on 2 h of simulated driving, compared with an alcohol treatment (mean blood alcohol content = 0.07%). Data were collected from the 64 male participants on the primary driving task, psychophysiology (0.1 Hz heart rate variability), and subjective self-assessment. The results revealed that the full sleep deprivation and alcohol group exhibited a safety-critical decline in lane-keeping performance. The partial sleep deprivation group exhibited only noncritical alterations in primary task performance. Both sleep-deprived groups were characterized by subjective discomfort and an awareness of reduced performance capability. These subjective symptoms were not perceived by the alcohol group. The findings are discussed with reference to the development of systems for the online diagnosis of driver fatigue. Potential applications of this research include the formulation of performance criteria to be encompassed within a driver impairment monitoring system.