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.