In this paper, an experiment aimed to explore the question whether route guidance decreases mental workload in car drivers, is described and the effects of route guidance on other sub-tasks of car driving, vehicle control and paying attention to the surrounding traffic, are investigated. Another research question was how the driver regulates his speed and mental efforts at different levels of mental workload. Speed has been used as a measure for compensating driver behaviour. The average inter-variability have been manipulated by decision support and familarity of the route as independent variables. The main results where: (1) When decision support is given and/or the subject drives on an unfamiliar route; (2) Decision support and familiarity of the route did not influence the quality of vehicle control; (3) The quality of paying attention to the surrounding traffic was dependent of the mental workload. When decision support was given traffic was better observed by subjects; and (4) Average speed depended on the amount of mental workload. When the workload was high the speed reductions tended to be insufficient to keep the performance of attending the traffic on an acceptable level. (A) For the covering abstract of the seminar see IRRD 839239.
Abstract