Communication and Interpretation of Results of Railroad Hazardous Materials Transportation Route Risk Analyses

Railroad hazardous materials transportation route risk analysis 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 more effectively present, interpret and communicate risk results. The analysis accounted for the major factors affecting risk: infrastructure quality, traffic volume, population exposure along the 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 geographical 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 regarding 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.