Estimation of transit passenger origin-destination matrices from passenger counts in congested transit networks

This paper deals with the transit passenger origin-destination (O-D) estimation problem using updated passenger counts and outdated prior O-D matrix while congestion in transit networks is considered. The bi-level programming approach is extended for the transit passenger O-D updating problem where the sum of error measurements in passenger counts and O-D matrices are minimized in the upper level and the stochastic user equilibrium assignment problem is solved in the lower level for congested transit networks. The transit assignment framework is a frequency-based transit assignment model in this paper, which can cater for elastic line frequencies and passenger overload delays due to congestion at transit stations. A heuristic solution algorithm is adapted for solving the transit passenger O-D estimation problem. Finally, a case study on a simplified transit network connecting Kowloon urban area and the Hong Kong International Airport was employed to illustrate the applications of the proposed model and solution algorithm.