Transit passenger origin–destination estimation in congested transit networks with elastic line frequencies

This paper deals with the transit passenger origin–destination (O–D) estimation problem by using updated passenger counts in congested transit networks and outdated prior O–D matrix. A bilevel programming approach is extended for the transit passenger O–D updating problem where the upper-level problem seeks to minimize the sum of error measurements in passenger counts and O–D matrices, while the lower level is the stochastic user equilibrium assignment problem for congested transit networks. The transit assignment framework is based on a frequency-adaptive transit network model in this paper, which can help determine transit line frequencies and the network flow pattern simultaneously in congested transit networks. A heuristic solution algorithm is adapted for solving the transit passenger O–D estimation problem. Finally, a numerical example is used to illustrate the applications of the proposed model and solution algorithm.