This paper describes an experiment to study divided attention while driving, where a task environment was created that simulated both fundamental driving tasks (lane-tracking and reacting to peripheral visual information) and RTI. Modalities of RTI that were varied were: Low to high memory requirement; Self-paced or machine-paced presentation; Numerical or spatial presentation; Vocal or manual responding. An essential element in the study is that the difficulty of lane-tracking and the RTI tasks is adapted to individual capacity in single task conditions. This allows for direct comparison of young and older drivers with regard to effects of dividing attention. The simulator tasks were presented to 24 young (25-40) and 24 older (60-80) experienced drivers, who each participated in a session of approximately 2 hours' duration. Both young and older drivers performed well on the basic driving tasks when no RTI was present as well as on the RTI tasks when no driving was required. When the RTI tasks were combined with driving, performance of older drivers in both types of tasks dropped significantly more than performance of the young. Froma safety point of view, the increased number of misses of peripheral stimuli and increased course deviation are particularly important. With regard to RTI modalities it appears that high memory requirements, machine-paced presentation and manual responding (as opposed tovocal) have particularly strong negative effects on older drivers' performance. This study is part of the DRIVAGE project V1006 'Factors in elderly people's driving abilities' within the DRIVE programme of the Commission of European Communities.
Abstract