To date management of fatigue in professional drivers has largely focused on strategies that limit the amount of time spent on the job. These approaches have, however, not taken into account the well-documented effect of time of day. Consequently, the likely impact of the pattern and timing of work and rest has received little attention. The results revealed that the group of drivers who did the shortest trips and worked the shortest weekly hours were the lowest reporters of fatigue, although longer hours were not always associated with the highest reporting of fatigue. In contrast, the shortest working hours were associated with earliest onset of fatigue. For all drivers, the influence of circadian rythms was evident in the occurrence of fatigue, with better management of the problem evident among drivers who were able to arrange the timing of rest to more closely coincide with periods of fatigue. Thus, time of day appeared to be a more important influence in determining effective rest than did period of work. These findings raise questions about the validity of the assumption underlying work hour regulations for long-distance drivers which, currently, are universally based on duration of work.
Abstract