Do drivers self-regulate their engagement in secondary tasks at intersections? An examination based on naturalistic driving data

Using naturalistic driving data, this study explored the prevalence of engagement in secondary tasks whilst driving through intersections, and investigated whether drivers manage and self-regulate such behaviour in response to variations in roadway and environmental conditions. Video recordings of in-vehicle and external scenes were coded for precisely defined categories of secondary tasks and related contextual variables. The findings indicated that nearly one-quarter of the total driving time at intersections was spent on secondary activities and that lower engagement occurred within intersections compared to phases immediately upstream or downstream. Drivers were less likely to occupy themselves with secondary tasks when their vehicles were moving than when they were stationary. Elderly drivers showed less inclination to perform secondary tasks than did younger drivers. Lastly, drivers tended to perform secondary tasks less frequently at intersections managed by traffic signs than those controlled by traffic lights, when they did not have priority compared to when they had priority, and in adverse weather conditions compared to fine weather conditions. In conclusion, drivers appeared to self-regulate secondary task engagement in response to roadway and environmental conditions. Specifically, they exercised self-regulation by reducing their secondary task engagement when the driving task was more challenging. The findings from this study provide preliminary evidence for targeting the education and training of drivers and media campaigns related to safe driving strategies and managing distractions.