Measuring Safety Performance in the extra-urban Road Network of Lombardy Region (Italy)

Road Network Screening (RNS) is a process to evaluate the safety performance of the whole road network and identify worst performing roads. Currently, literature provides many models and methods for RNS. Moreover, several frameworks of RNS were issued at the European National Level over time. However, even if sophisticated models and methods could be preferable for their computational accuracy, they may be far from the capabilities of practitioners. In addition, other issues such as availability of operative attributes and data quality and processing persist. For instance, accurate crash location, which is crucial for detailed analyses of high crash rates at some locations, is still an issue: many road administrations pointed out that coordinates miss or are inaccurate in many cases. Within this context, this paper proposes a straightforward operational framework to evaluate safety performance for RNS, using a flexible rationale that integrates crash, traffic, and road data, respectively. More precisely, this framework: (a) handles crash location data without using spatial coordinates; (b) computes the crash rate index at different administrative levels; (c) shows results by Geographic Information System (GIS) maps. This framework is applied to the whole extra-urban road network of the Lombardy Region (Northern Italy) using 30.000+ crash data provided by the Regional Institute for Lombardy Policy Support (PoliS). Road authorities could adopt this framework to perform an accurate safety screening on the road network aimed at rational planning of safety interventions.