The recent Moving Ahead for Progress in the 21st Century Act (MAP-21) emphasizes performance-based, outcome-driven planning processes to meet performance targets. One area of performance-based planning highlighted by MAP-21 is safety planning. State DOTs and metropolitan planning organizations (MPOs) will be required to document how their SHSP supports the state safety performance targets. To maximize safety improvements for every dollar of investment, cost-effective analysis is used within sub-disciplines of safety planning, but is rarely used to compare projects across the 4 Es of safety (education, engineering, enforcement, and emergency response).

This paper proposes two methods for cost-effectiveness analysis for safety investment decision-making across the 4 Es – a quantitative and a sketch level method. The quantitative method is appropriate when detailed, quantitative results are desired and sufficient basis exists to make quantitative assumptions for all variables in the analysis, including crash modification factors, duration of effectiveness, geographic extent of effectiveness, and costs. The sketch-level method is appropriate when quantitative information is not complete, insufficient basis exists upon which to make quantitative assumptions, or when detailed results are not necessary. Both methods result in multi-disciplinary safety strategies grouped by their relative cost-effectiveness, and this information can be used as one factor among others in ranking countermeasures for implementation. This paper concludes with example analysis results from the application of the cost-effectiveness analysis methods to DOT’s safety projects.