The present roadside survey seeks to elucidate the incidence of tiredness among nighttime cab drivers by comparing self-assessed level of tiredness with the results of a simple visual reaction test. Attempts to separate various forms of fatigue from sleepiness are notmade, as it appears less important in studies of everyday traffic than in experimental investigations. One-hundred-and-twenty cab drivers of vacant cabs were stopped by the police on a major highway justoutside the city of Copenhagen. Eight drivers declared themselves rested, 38 tired, and 2 very tired. The reaction test showed considerable individual variation, but subdivision of the drivers according to level of tiredness demonstrated a statistically significant and uniform difference throughtout the night (p less than 0.0001). One self-assessed tired driver was reclassified to the group of very tiredbased on the questionnaire and reaction test. The investigation indicates that accidents due to "driver asleep" would be expected amongthe three (2.5%) very tired cab drivers. The questionnaire and visual reaction test turned out to be complementary in the present studyand are both useful implements for future roadside surveys of tiredness in nighttime traffic. (A).
Samenvatting