Abstract
A number of technological countermeasures have been proposed to reduce the incidence of accidents due to driver impairment, that is, the degradation of driving performance due to the influence of fatigue, alcohol, drugs, distraction, and emotional stress. Few studies have been concerned with those driver-system interaction issues underlying this category of technology. Eighteen male participants took part in a repeated measure design in which they performed simulated journeys with and without impairment feedback. The diagnosis and assessment of impairment were based on the quality of vehicular control. Impairment feedback was presented in the form of two interface designs, one providing 3 levels of feedback and another capable of 9 levels of feedback. The results indicate that impairment feedback counteracts the characteristic degradation of driving performance due to time-on-task with respect to vehicular control. However, the presence of feedback (in either form) failed to influence participants' decision to discontinue the journey. In addition, impairment feedback failed to significantly influence psychophysiological effort, subjective fatigue, or subjective mental workload. The implications of these findings for future research and development are discussed.