Post impact trajectory of vehicles at metropolitan intersections

Abstract

This report describes the path of vehicles following a collision with another vehicle at a metropolitan intersection. The aim was to provide guidance to transport authorities on roadside design at intersections to protect vehicles from secondary impacts with roadside objects. Detailed information from in-depth investigations of 78 intersection crashes was analysed. Crashes at singalised and unsignalised intersections were analysed separately. Thirty two vehicles at signalised and unsignalised intersections (16 at each) were involved in a secondary collision. Nine of these collisions were more severe than the initial vehicle-to-vehicle collision, three at signalised intersections and six at unsignalised intersections. Following the vehicle-tovehicle impact at both signalised and unsignalised intersections, more than half of the vehicles came to rest within 10 metres of the impact point. However, more than a quarter travelled 15 metres or further and around 10% travelled further than 27 metres. It was found that 40% of vehicles at signalised intersections crossed the designated pedestrian crossing areas following a collision between vehicles. It was also found that 14% of vehicles involved in crashes at signalised intersections departed the roadway. This poses a significant risk to pedestrians who are in the vicinity of junctions at the time of collisions. Graphical representations of the percentage of vehicles that travel through a given sector relative to the impact point following the metropolitan intersection crashes were developed. These can be used to determine the chance of a vehicle having a secondary collision with roadside objects.