The document presents techniques for constructing and evaluating railroad grade crossing hazard indexes. Relative and absolute hazard indexes are constructed and compared in performance with some hazard indexes in general use. The DOT-AAR crossing inventory for all public crossings in the United States and the FRA accident data base for 1975 are used. Various measures and displays of performance of hazard indexes in predicting the hazard of crossings as functions of their inventory characteristics and as manifest in the U.S. accident experience of 1975 are given. The levels of performance that may be expected of various hazard indexes in various situations are given. Means for shaping a relative hazard index into an absolute hazard index are given. An introductory discussion is provided on the use of accident history in hazard indexes.
Samenvatting