A framework for assessing hazmat risk at nodes of transport networks

A new hybrid approach for the rail-truck intermodal transportation problem of hazardous materials (hazmat) is proposed. This approach analyzes and assesses the risk in the terminals or storage facilities in the transport network. Hybrid techniques are inherently complex since they combine elements of different nature (quantitative and qualitative techniques). This hybrid approach is based on an event tree analysis (ETA) method, which makes use of a decision tree to logically develop the possible outcomes of an initiating event. This hybrid approach focuses on the interaction between hazmat and their danger characteristics in railroad terminals. ETA describes incidents from three different perspectives: induced incidents, incidents caused by external causes, and incidents caused by simultaneous and independent events. Incidents are modeled through conditional probabilities under normal conditions based on the records from PHMSA [1]. The results show that the magnitude of risk depends largely on the dangerousness level of the interaction among materials in the transport node and the time when external events happen. This approach is also proposed as a new tool to help the decision maker in transport networks to assess better the latent risk and magnitude of the incidents, when several dangerous materials are in a node at the same time.