A significant proportion of road trauma occurs at intersections. Understanding driver behaviour at intersections therefore has the potential to lead to significant injury reductions. This paper presents the findings of an on-road study investigating the nature of errors made by drivers at intersections.

To understand how the complexity of modern intersections shapes behaviour these are compared to the errors made mid-block, and the role of wider systems failures in intersection error causation is investigated.

Twenty-five participants drove a pre-determined route, incorporating 25 intersections, in an instrumented vehicle. Two in-vehicle observers recorded the errors made while a range of other data was collected, including verbal protocols, video, eye glance behaviour and vehicle data (speed, braking, lane tracking).

Participants also completed a post trial cognitive task analysis interview. Participants were found to make 39 different error types, with speeding violations being the most common. Drivers made significantly more errors at intersections compared to mid-block, with a failure to indicate on approach to the intersection, indicating too late and travelling too fast to turn being common errors observed.

Drivers also made more errors at partially signalised crossings compared to fully signalised intersections. A range of system-wide prevention strategies to minimise intersection errors are proposed.