城市轨道交通网络可靠性和运输服务质量评估

为评估区间通过能力下降对城市轨道交通网络可靠性和运输服务质量的影响，首先，以区间通过能力下降前后乘客的相对广义出行费用确定乘客的出行是否可靠，并以出行可靠的乘客占比评估网络的可靠性；其次，以乘客的平均广义出行费用评估网络的运输服务质量，采用基于改进Logit模型的随机用户均衡配流模型计算乘客的广义出行费用，并通过MSWA （method of successive weighted averages）算法求解该模型；然后，通过区间影响的乘客占比、区间介数分别识别网络的重要区间；最后，以武汉地铁为例分析重要区间通过能力下降后的网络可靠性和运输服务质量. 仿真结果表明:受区间影响的乘客占比识别的重要区间对城市轨道交通网络的可靠性和运输服务质量产生重要影响；重要区间多与换乘站直接相连，并且各重要区间能影响网络中12.24%～13.96%的乘客；为保证武汉地铁网络可靠性高于0.95，网络最多能容忍区间介数识别的3个重要区间的能力下降20%，或区间影响的乘客占比识别的1个重要区间的能力下降20%；随着下降区间数目和下降比例的升高，网络的可靠性持续下降，但网络的运输服务质量下降的情况会有所减弱. 

Reliability and Service Quality Evaluation for Urban Rail Transit Network

To evaluate the impact of carrying capacity reductions on the reliability and service quality of an urban rail transit network, firstly, the generalized travel cost before and after capacity reductions was used to determine whether passengers’ travel was reliable. The network reliability was evaluated based on the fraction of reliable passengers whose travel was reliable. Secondly, the transportation service quality was evaluated based on the passengers’ average generalized travel cost, which was computed with the stochastic user equilibrium model based on an improved Logit model. The model was solved with the MSWA (method of successive weighted averages) algorithm. Then, the critical sections were identified with the fraction of passengers affected by sections and sections’ betweenness, respectively. Finally, a case study of Wuhan metro network was conducted to analyze its reliability and transportation service quality after carrying capacity reductions occur in the critical sections. The results show that the reliability and transportation service quality of this urban rail transit network are affected by critical sections identified with the fraction of the passengers affected by sections. Most of the critical sections are connected to transfer stations and each of them can affect 12.24%?13.96% of all passengers in the network. To ensure the reliability of Wuhan metro network exceeds 0.95, the network can tolerate at most a 20% decrease in carrying capacity at the three most critical sections identified with their betweenness, or a 20% decrease in carrying capacity at one critical section identified with the fraction of passengers affected by sections. As the number and fraction of capacity reductions increase, the reliability of the network continues to decline, but the reduction rate in transportation service quality gradually decreases.