Innovative Estimation of Crash Reduction Factors

The crash reduction factor (CRF) for road safety treatments is the expected percentage change in crash rate after a treatment is installed. An innovative method was used to estimate CRFs by incorporating literature reviews, quantifying the quality of the study and the quality of the statistics cited, and disaggregating CRFs in terms of treatment, speed and type of crash. For treatments involving horizontal curve alignment, high reliability literature (reliability score greater than 20) was difficult to find. Nevertheless, the findings indicated that for crash types other than “head-on”, the CRFs in current use appeared to be too high.