Update of Florida Crash Reduction Factors and Countermeasures to Improve the Development of District Safety Improvement Projects

Abstract

Crash reduction factors (CRFs) are used to estimate the expected reduction in crashes that will occur during a given period as a result of implementing a proposed safety improvement project. This report describes an effort to update the existing CRFs for the Florida Department of Transportation (FDOT) for use in benefit-cost analysis and to develop an automated mechanism to allow continued update of CRFs as new improvement projects become available. A web database application that runs on the FDOT intranet was developed. The system, called Crash Reduction Analysis System Hub (CRASH), provides a means to systematically maintain Florida's safety improvement projects. It also provides capabilities to update CRFs based on the before-and-after study method and perform benefit-cost and before-after analyses for project evaluation. As part of this study, a comprehensive literature review on the CRF development methods was performed and a state-of-the-practice survey of the State DOTs was also conducted. This report also includes a review of the new CRF development effort that is being undertaken by the Federal Highway Administration to apply the Empirical Bayes method to overcome the well-known regression-to-the-mean problem associated with the current before-and-after development method.