Safety on congested urban motorways

The metropolitan Melbourne motorway network carries 40 per cent of urban arterial road travel and casualty crash numbers have been increasing despite a decreasing trend on other urban roads. Infrastructure is rarely mentioned in Police crash reports as being involved in the urban motorway crashes, rather mention is made about traffic conditions and vehicle-to-vehicle interactions. Analysis was undertaken to test the hypothesis that the dynamic of the traffic flow, which causes congestion and requires complex driver responses, is a significant component of the casualty crash problem. A relationship between ‘traffic state’ and crashes was observed.