Impact of traffic environment and cognitive workload on older drivers' behavior in simulated driving

As the use of in-vehicle technologies became more popular, there is concern about a concomitant increase in driver distraction arising from their use. While the introduction of voice recognition systems is intended to reduce the distraction due to manual operation of these units, a significant proportion of the distraction associated with their use may arise not from the manual manipulation but rather the cognitive consequences. It is also known that the risk of inattentive driving varies with age. In this study, the impact of cognitive workload and traffic environments on older drivers' behavior was investigated in a driving simulator. To assess the impact of advancing age on driving performance degradation under a dual task condition, the performance of 63 drivers, divided into younger (20-29) and older (60-69) age groups, was evaluated. The authors also considered driving behavioral differences in the context of urban and highway driving, appropriately counterbalanced. At a specified location in the two scenarios, subjects were asked to complete a series of auditory tasks of increasing complexity. Comparisons of younger and older drivers' driving performance, including forward velocity, speed control, standard deviation of lane position and steering wheel reversal rate, were conducted. Results indicated that age and traffic environment impact both driving performance and compensatory behavior during dual task conditions.