ELDERLY CAR DRIVERS IN A SIMULATOR: A VALIDATION STUDY

The aim of this study was to study the validity of the simulator for studies of the driving behaviour of elderly (65+) car drivers. Elderly car drivers are the fastest growing segment of the driver population. In comparison with field studies, a simulator is advantageous inasmuch as the accident risks of real traffic are avoided, and behaviour in situations which would pose an unacceptable risk in a field study can be observed and measured. In addition, the experimental situation is under full control. The drawback is that even the best simulators cannot produce an entirely convincing illusion of real driving, and this can be reasonably expected to influence driving behaviour. In the study, the way elderly test subjects drove along the same route with an instrumented car in real traffic and with the VTI simulator was compared. Interview and test data were also collected. The results show that the test subjects drove in broadly the same way in both the simulator and the instrumented car. The most important differences between the simulator and the instrumented car were as follows: (1) In the simulator, mean speed on 70 km/h sections was lower; (2) The test subjects drove further to the right on the carriageway in the simulator; (3) Variation in speed, lateral position and steering wheel movements was greater in the simulator; (4) Test subjects braked significantly more often and harder in the simulator; and (5) Familiarisation effects such as higher speed and less variation in speed and lateral position occurred to a much greater degree in the simulator. (A)