A case study of 'continuous risk profile' approach for hotspots identification on Korean expressways

This paper suggests a hotspot identification method based on crash severity using Continuous Risk Profile (CRP) approach which is a recently introduced method for identifying high collision concentration locations. The process of selecting hotspots is an essential step for road safety improvement projects since it provides decision makers with reasonable evidences for the allocation of budgets in a cost-effective manner. Therefore roadway sections that could maximize the reduction of crash costs are needed to be investigated as target sites for treatments. In this study, two types of crash severity weights are applied to each collision and then, CRP diagrams are illustrated by the values of crash frequency, equivalent property damage only (EPDO) and severity weighted frequency based on the number of fatalities and injuries. Top seven sites which include high peak locations in each CRP are selected and grouped by the approaches, and accident costs per unit length are compared to evaluate the potential cost reduction of the three groups. As a result, the EPDO group is expected to lead the most cost savings if safety improvement projects are performed. Findings from the paper will contribute to both enhancing accuracy for identifying hotspots and saving social costs caused by traffic accidents.