Spatial analysis of road crashes involving vulnerable road users in support of road safety management strategies

On urban road networks, approximately 2 out of 3 fatalities involve pedestrians, cyclists and motorcyclists, collectively referred to as “vulnerable road users” (VRU) due to their insufficient physical protection in the event of a collision. For a safer and more sustainable road transportation system, adequate protective countermeasures need to be introduced for this user category. However, related (and limited) resources restrict any safety improvements to certain high-risk sites with elevated rates of road traffic collisions. This study reports the results of a spatial distribution analysis of traffic collisions involving VRU in Turin over the period 2006-2016. The traffic road collisions database from the Italian National Institute of Statistics (ISTAT) was used for this purpose. Crash data were firstly geo-localized, and then analyzed using Geographic Information System technologies. A cluster analysis and a Kernel Density estimation were used to build spatial patterns of crashes involving VRU. Hazardous sites were identified on a metropolitan scale. Incorrect estimates of the actual collision frequency, which are typical of studies conducted over short periods, were avoided by considering only those sites where collision rates remained significantly high throughout the entire observation period (eleven years). The results show that clusters occur at intersections, many of which are located along corridors affected by heavy traffic flows and wide cross-sections. A further analysis was conducted to explain the role played by the geometric configuration (layout) of most hazardous sections and intersections in the level and severity of injuries and fatalities.