LAUSR

Abstract Of the road crashes involving personal injury in Hong Kong, over 70% involved at least one commercial vehicle. Besides, the proportion of older drivers in the transport sector has been increasing due to the shortage of labor and ageing population. It is believed that increase in age can have adverse impact on driving performance, even that professional drivers may possess better driving skill than non-professional drivers and the age-related impairment can be offset by task familiarity of professional drivers. In this paper, a driving simulator experiment was conducted to address this question. Additionally, possible factors that affect the driving performance of professional drivers and that of non-professional drivers were examined. A total of 50 participants were recruited and 94 tests were completed. Driving performance was assessed in terms of standard deviation of lateral position (SDLP), standard deviation of heading error (SDHE), mean heading error (MeanHE) and standard deviation of speed (SDspeed). Results of random intercept models indicate that lateral and speed control performances of mid-aged drivers were better than those of older drivers. Then, disaggregated models were established for professional and non-professional drivers respectively based on the results of market segmentation analysis. It was found that lateral and speed control performance of mid-aged professional drivers were better than that of older professional drivers. In contrast, older non-professional drivers were more likely to have degraded steering performance under the high traffic condition. Results of this study are indicative to the driver management strategies of the transport operators for sustained safety improvement of commercial vehicle fleet.