Naturalistic Driving Performance during Secondary Tasks

Data from 36 drivers involved in a naturalistic driving study was analyzed to determine the frequency and conditions under which drivers engage in secondary behaviors and to explore the relationship these behaviors might have with driving performance. Researchers coded 1,440 five-second video clips of the drivers’ faces for the occurrence of specific secondary behaviors and the duration of glances away from the forward scene. Corresponding performance data from the instrumented vehicles were used to calculate variability of steering angle, mean and variability of lane position, mean and variability of throttle position, and variability of speed. All categories of secondary behavior were associated with significantly higher variability in steering angle. The results for other performance measures were mixed. In summary; driving performance measures vary with differing tasks, with no single driving performance indicator that is obviously predictive of drivers’ engagement in secondary tasks.