中文摘要：

为定量衡量因路段降级原因导致路网通行能力的丧失量，分析出行者在降级路网中的路径选择行为将导致何种网络交通流平衡状态，通过将降级路网划分为车流外界因素导致路段可通行能力降级和路段上车流量增加导致道路服务水平的下降两种类型，辨别旅行时间长短与旅行时间波动对出行者路径选择行为的影响，推导出同时考虑这两方面因素影响的可变路径旅行时间风险度量；在此基础上建立了降级路网中的交通流平衡分析模型，该模型满足存在性和惟一性，并能正确描述出行者对降级路网结构认知差异性情况下的网络交通流平衡状态。通过实例展示了不同旅行可靠性要求下，出行者对路径旅行时间长短的权衡关系以及整个路网交通流平衡结果。

英文摘要：

For calculating the lost capacity of the degraded road network and finding what kind of state of equilibrium traffic flow reaches on the degraded road network, it was revealed that road network was degraded by two kinds of cause; one came from outsides of traffic flow, such as bicycle flow, pedestrian flow and weather, and the other was induced by increasing traffic flow amount through links in traffic network. After discriminating effect of travel time and variance of travel time on traveller route choice, travel time risk criterion of a variable path was introduced which included both travel time and variance of travel time. Based on the new criterion, an equilibrium traffic flow analysis model in the degraded road network was established, which had property of existence and uniqueness. The analysis model can analyze what kind of equilibrium traffic flow will reach on the degraded road network. An example was given to show traveller trade off between path travel time and demand of travel reliability while they confront alternative routes, and results of equilibrium traffic flow on different cases of weight parameter were also displayed.