In this paper, the risks of transporting dangerous commodities by truck and rail are expressed by four constituent elements: accident rates, spill probabilities in an accident situation, hazard areas for different classes of damage, and expected impacts on population and environment along a specified road or rail corridor. Changes in the level of risk for individual shipments are considered for different material properties, spill characteristics, and transportation environments. Under most conditions, trucks exhibited significantly higher accident rates than trains. These results were consistent for two measures of shipment exposure: on a per-vehicle-kilometer and a per-tonne-kilometer basis. On the consequence side, the relative merits of one mode over another were not as clearly defined. Both trucks and trains reflect certain safety advantages over one another depending on the nature of the material being shipped and the assumed transport environment. (A)
Abstract