APPLICATION OF NEW ACCIDENT ANALYSIS METHODOLOGIES. VOLUME II: A USERS MANUAL FOR BEATS. FINAL REPORT

Researchers in the field of accident analysis have long been aware of the problems associated with drawing statistical inference on safety using accident data. Aside from the problems of accessibility and quality, accident data present a real challenge when it comes to statistical analysis. One of the most serious problems in accident analysis is the regression-to-the-mean bias which occurs due to the non-random site selection process in safety measure evaluation studies. This study presents a new empirical Bayes method (EBEST) which adjusts for regression-to-the-mean bias. Three typical applications in accident analysis are considered for regression-to-the-mean bias, namely: (1) the evaluation of safety treatments; (2) the identification of high hazard locations; and (3) the assimilation of information from multiple safety measure studies (meta-analysis). A computer program was developed to execute these analyses as a part of this study. This manuscript describes the EBEST (Empirical Bayes Estimation of Safety and Transportation) methodology and presents examples of how the method works for each of the three accident analysis applications. This volume, Volume II, is a users manual for the BEATS computer program.