Can We Predict the On-Road Performance of Older Drivers?

A study of drivers aged 50-90 was carried out to assess which, if any, of a range of measures were useful in predicting on-road performance. The study had three phases. In Phase One almost 2000 drivers completed an extensive self-report questionnaire, the Aging Driver Questionnaire, or ADQ. In the ADQ they described their personal and driving history, their driving behaviour and their attitudes and opinions on a variety of driving issues. Measures of general health, personality and intelligence were also taken. In Phase Two a subsample of those completing the ADQ (N=600) completed an extensive battery of laboratory tests of their cognitive and physiological capacities. In Phase Three 200 of this laboratory test sample completed two assessed on-road drives. The key results were that a) scores on the Manchester Driver Behavior Questionnaire showed that relatively high levels of errors and lapses behind the wheel were predictive of involvement in active accidents, while passive accident involvement was associated with a relatively high number of lapses, b) lapses were also associated with some indices of on-road performance, c) in general, performance on the cognitive and physiological laboratory tests was not associated with on-road performance, and d) the best predictor of on-road performance was a relatively good score on a multiple choice test of driving knowledge, an assessment of driving knowledge offered in multiple choice format.