Life-Cycle Cost Analysis of Highway Intersection Safety Hardware Improvements

A methodology is proposed for project-level life-cycle cost analysis of highway intersection safety hardware improvements. It incorporates a disaggregated risk-based approach for computing the safety index that could be used to assess intersection vehicle crash risks affected by the conditions of intersection safety hardware such as signs, signals, lighting, pavement markings, and guardrails. With safety indices estimated before and after implementation of an intersection safety hardware project, the annual potential for safety improvements (PSI) could be computed using the concept of consumer surplus. The annual PSI is further converted into dollar values and extrapolated to the overall intersection safety hardware service life cycle, defined as the useful service life of longest-lasting intersection safety hardware, to determine the maximum project-level life-cycle benefits of intersection safety hardware improvements. A computational study is conducted for methodology application and validation using 5-year data on 226 intersections in Ozaukee County, Wis. The proposed methodology could be adopted by state and large-scale local transportation agencies for intersection safety hardware project evaluation and investment decision making.