中文摘要：

有害物品运输的路径问题实质上是对有害物品相关的风险考量，对风险如何进行测量，直接影响路径选择的结果。在有关有害物品运输文献中，已经提出了多种风险测量模型，最广泛使用的风险定义是路径中节点间发生事故后果的期望值，它等于事故发生的可能性与其可量化的结果的乘积。所提出的风险度量模型均没有考虑到事故分级对路径风险评价结果的影响。为此，提出将事故分级引入风险度量模型，并对原有模型进行相应改进，可以有效地克服原有模型的计量误差，减少路径运输风险。

英文摘要：

Routing problem in transporting hazardous materials substantially is a problem of quantifying the relevant risk of the hazardous materials and how to measure to risk;it is a safety system engineering routing project for directly reducing the impact of transportation risk.Many risk models had been reported.The most widely used definition of risk is the expected consequence of an incident,which,for each edge of the network,equals to the product of the incident probability and a quantifiable consequence.All above-mentioned risk models haven＇t considered the impact of accident gradation on assessed consequence of routing risk.So,the accident gradation is introduced in the risk measurement model,and the original model is correspondingly improved.The quantification error in the original models could be effectively overcome,and the risk in routing could be reduced.