Exposure to potential collisions between trains and motor vehicles at railroad-highway grade crossings throughout the United States has created a serious problem with regard to the convenience and safety of highway travel. This problem has grown tremendously during the past few decades because of the rapid growth in vehicle-miles of travel. Accidents which occur at these crossings, although a numerically small part of the overall highway accident problem, are usually severe and result in a relatively high number of deaths. Possible solutions to the grade crossing problem have included better enforcement of laws and regulations which apply to motor vehicle drivers at grade crossings, improvement of the level of grade crossing protection, and construction of grade separations. Application of the latter two alternatives is economically limited. Based upon engineering principles, a feasible solution is to develop some type of priority rating system for the improvement of the level of grade crossing protection. However, criteria and warrants for protective devices have yet to be developed for application on a rational basis. The general warrants used by many states result in priority ratings based on subjective judgement and not on hazard. The objectives of this research investigation were to develop mathematical models that measure the relative safety or hazard of urban grade crossings and to establish a priority rating system, based on these models, for determining protection improvements in urban areas. By applying the results of this research, it may be possible to improve substantially the safety of highway travel at urban railroad-highway grade crossings. The protection improvement warrants and priority rating system allow a systematic reduction of hazard at these grade crossings. In addition, the analytical procedures developed in this investigation can be applied as an effective tool for the analysis of other transportation safety problems.
Samenvatting