Probit-type reliability-based transit network assignment

This paper proposes a new probit-type reliability-based transit assignment model in a congested network with unreliable transit services. A new disutility function is developed to model the passenger route choice behavior under unreliable conditions; passengers will make a trade-off between the transit service reliability and the expected travel time for their route choice. In the proposed model, the total transit passenger demand is fixed, but the in-vehicle travel times by transit routes are formulated stochastically because of unreliable traffic conditions, particularly for buses on the road network. The effects of congestion on transit networks, such as elastic transit line frequencies and passenger overload delays, are also considered in the proposed model. A numerical example is provided to illustrate the applications of the proposed model and solution algorithm. It is shown that the traditional probit-type stochastic user equilibrium transit assignment is a special case of the proposed model. The findings also reveal the distribution of passenger waiting times and their overload delays at congested transit stations.