ABSTRACT
A transactional perspective for effects of driver stress and fatigue on performance is outlined. Stress may impair performance through its effects on cognitions of the traffic environment. Different aspects of driver stress, such as aggression or emotional distress, are associated with characteristic styles of appraisal and coping. Four studies are reviewed which apply the transactional perspective to stress effects on simulated driving. In each study, stress factors (including fatigue) were associated with performance impairment primarily in underload conditions. These findings suggest that stress-related impairment is due to breakdown of adaptive regulation of effort, which in turn is a consequence of coping and motivational processes. At a practical level, vehicle systems should be designed and assessed for tolerance of driver underload.
