Understanding Right-Turn Car–Cycle Conflicts at Intersections: Findings from Site-Based and In-Car Observations

The Dutch field trial for PROLOGUE, the European naturalistic driving project, combined in-vehicle and site-based techniques to study car–cycle conflicts at intersections. Results, briefly reported here, indicated that the intersection layout limited the driver's perception of the possible presence of a cyclist more when the car was stopped than when the car was not stopped. Vehicle drivers adapted to this limitation by putting more effort into detecting the presence of cyclists in a timely way. Car–cyclist conflicts were less frequent and less severe when the car had stopped than when the car had not stopped, because of the lower speed of approach and because the bicyclist had a head start in time and in distance. The study revealed an intricate relationship among intersection design, traffic light phasing, and driver–bicyclist interactions and allowed the interactions to be explored.