Prevalence and self-regulation of drivers’ secondary task engagement at intersections: An evaluation using naturalistic driving data

On the basis of naturalistic driving data, this study examined the prevalence of secondary task engagement at intersections and investigated how drivers self-regulate and manage such activities in accordance with changing roadways and demand situations. Video recordings were viewed to identify secondary tasks in which drivers engaged and situational factors, specifically those related to the complexity of driving situations. Results showed that one-third of the total intersection time was allocated to secondary task engagement and that greater engagement occurred at upstream and downstream areas of intersections than at areas falling within intersections. Drivers tended to more frequently engage in secondary tasks when their vehicles were stationary than when the vehicles were moving. Elderly drivers were less likely to engage in secondary tasks than younger drivers. Finally, drivers were less likely to engage in secondary tasks when they did not have priority than when they had priority and at intersections managed through traffic signs than in those controlled by traffic lights. In conclusion, drivers appear to engage selectively in secondary tasks at intersections in accordance with changes in the demands imposed by driving and roadway situations. In such circumstances, drivers likely respond to increased demand and reduce secondary task engagement to preserve processing resources. The findings offer the preliminary information necessary to develop driver training/education and awareness programmes on managing distractions and safe driving strategies.