Effective and Fair Identification of Hazardous Locations

The two fundamental objectives of a safety management system are to prevent as many crashes as possible and to reduce the difference in risk faced by individual road users. An index of crash frequency and an index of crash cost are proposed to address these two criteria in the hazard identification phase of safety management. An index of crash cost is used to incorporate severity in identification criteria. Safety performance functions based on negative binomial distribution are used to predict the typical crash frequency at the location. The proposed methods can be used to rank locations and to evaluate the degree of hazard at an individual location without referring to other locations. These methods determine the evidence of hazard at all types of locations (intersections and segments), and they can use crash data from periods shorter than 1 year. Indices of crash frequency and cost were evaluated and found helpful for safety management that reduces the number of crashes and risk variability across a road network.