The study focused on the incidence and importance of tiredness among young male car drivers in nighttime traffic. It took place on a major highway in Copenhagen County, Denmark, and was performed as roadside surveys in the hours between midnight and 6 a.m. The study consisted of a questionnaire with self-assessment of tiredness followed by a simple visual reaction-time test. Two hundred and forty nighttime drivers and 40 early morning drivers joined the study. One hundred and twenty-three nighttime drivers declared themselves as rested, 106 as tired, and 11 as very tired. Thirty-seven early morning drivers declared themselves as rested, while the remaining three declared themselves as tired. The drivers' self-assessed level of tiredness corresponded well with the results of the simple visual reaction-time test, but one self-declared tired driver had to be reclassified as very tired. The visual reaction-time test henceforth showed a mean reaction time of 0.189 seconds for the rested drivers, 0.223 seconds for the tired, and 0.309 seconds for the very tired nighttime drivers. Mean reaction time for the early morning drivers was 0.190 seconds corresponding to 0.245 seconds in the equivalent nighttime group. The study shows tiredness as a common affliction among young male nighttime drivers.
Abstract