Robustness Assessments of Urban Rail Transit Networks Based on Network Utilization

Urban rail transit has become an important traffic mode in large cities and has brought great conveniences to urban residents, however traffic accidents often occur in daily operations, therefore the safety and robustness must be paid more attention. In this paper, the network utilization of urban rail transit networks (
URTNs
) is expressed by the travel time difference between user equilibrium and optimal system, and the travel time difference is considered as the assessment indicator of robustness. Meanwhile, Shanghai metro network is taken as the example to analyze the robustness of
URTNs
under different disturbances, such as node attack, link-demand attack and overall-demand attack. The results show that
URTNs
have better robustness subjected to the random link-demand attack than node attack, and the robustness decreases with the increase of the attack intensity when the network suffers overall-demand attack. Moreover, we find that the critical stations and links can be identified, and
URTNs
can be paralyzed when the attack intensity exceeds the critical threshold.