The Effect of Rerouting and Tank Car Safety Design on the

Railroads in North America have recently come under pressure to avoid transporting certain high hazard materials through metropolitan areas. There are two principal reasonsfear of terrorist attack and concern about the risk of an accident-caused release. Consequently, a number of municipalities are considering legislation to block hazardous materials transportation through their communities, thereby requiring the shipments to be rerouted. However, rerouting of hazardous materials is not without its own set of risks. The distance traveled, time in transit, number of visits to classification yards and the number of smaller population centers exposed to the risk would all increase. Furthermore, the track quality may be lower on the alternate routes. All of these factors increase risk but to date, no formal analysis comparing the relative risks for shorter urban routes versus longer more rural routings has been presented. In this paper we describe a comprehensive risk assessment model that enables evaluation of different rail route alternatives for transporting hazardous materials. Major variables considered are the length of the route, number of shipments, track quality, tank car safety design, chemicalspecific exposure area and population density. The model uses up-to-date measurements of accident probability as a function of track quality, tank car accident performance and chemicalspecific hazard analyses. We use the model to consider an example case in which the effect of both alternative routing and tank car design are considered and risk profiles for each are presented. What’s new? This paper presents an analytical model in which route-specific parameters can be compared to alternative design tank cars to assess their relative effectiveness in reducing the risk of hazardous materials transported by rail.