Prioritizing safety funding using severity weighted risk scores

Abstract

Limited funding availability requires government agencies to focus transportation funding on locations most in need of safety improvements. The Two-Output Model for Safety (TOMS) was created to prioritize segments and intersections for safety analysis. The TOMS compiles input data, prepares the data files so that the format and content are consistent, and then two different processes occur. The first is to segment roadways based on five variables: average annual daily traffic, functional class, lanes, speed limit, and urban code. The second is to assign the physical characteristics of the roadway to each individual intersection. TOMS outputs a segment file and an intersection file used for statistical analysis and are the “two outputs” referenced by the name of the model. The segments and intersections are analyzed using severity and total number of crashes at the sites. An excess weighted risk score was developed using an equivalent property damage only value to analyze the severity and number of crashes concurrently. The segments and intersections with the highest excess weighted risk scores are prioritized as locations for safety funding. A report compiler is then executed to create two-page safety reports that contain roadway and crash information organized in a manner that allows governing agencies to identify how many crashes are occurring at a site and the manner of collision for the crashes. The research presented in this paper shows that the simultaneous use of intersection and segment analysis combined with excess weighted risk scores can provide insight into the prioritization of safety funding.