In a driving simulator experiment the effects of electronic information systems on driving performance and workload are investigated. Subjects drove twice: in busy and quiet traffic. Within each ride, 5 conditions were presented: no information system; auditory route guidance (RG) only; traffic information (TI) only; and both systems combined: unscheduled, RG and TI were sometimes presented simultaneously; and scheduled, RG had priority. Both self-reported mental effort and heart rate were higher in map than RG conditions. Self-reported effort showed significant difference between all system conditions, except for traffic density. Scheduling had no effect on any of the variables except self-reported workload. variables except self-reported workload. Using a map, subjects swayed more and drove slower than in RG conditions. Speed was also lower in heavy traffic. This speed reduction is interpreted as subjects adapting to workload. Because of subjects' adaptation to workload, driving performance alone may not give full information about workload: other workload measures are necessary (A)
Abstract