Communication and interpretation of results of route risk analyses of hazardous materials transportation by railroad

Route risk analysis of hazardous materials transportation by railroad is receiving considerable new attention from industry and government. Such analyses are necessary for effective public policy and development of rational risk management strategies. However, route risk analysis is complex and generates results that can be difficult to properly interpret. Risk analyses are intended to provide risk managers with objective information about how to effectively manage risk and the most effective options to reduce it. This paper uses results from a quantitative risk analysis of hazardous materials shipped by rail to develop and illustrate several new techniques to present, interpret, and communicate risk results more effectively. The analysis accounted for the major factors affecting risk: infrastructure quality, traffic volume, and population exposure along shipment routes, as well as tank car design and product characteristics. Approaches for system-level and route-specific analyses are presented. Both absolute and normalized estimates of risk provide useful information. The question of interest and the user affects which type of information is most useful for effective decision making. Various graphical techniques enable risk metrics to be compared and contrasted, either in a geographic context or independent of it, depending on which is most useful. Identifying the locations that account for the highest concentration of risk and understanding the contributing factors will also clarify the mutual roles of carriers, shippers, and municipalities along a route in regard to risk management, reduction, and mitigation options. In addition, the techniques presented in this paper may also be useful for regulators and researchers who might be interested in a broader view of risk analysis at the network level.