Description:

Northwestern University Transportation Center presents:

"Transit Network Design Under Demand Uncertainty"

HONG K. LO
Chair Professor and Head of Civil and Environmental Engineering
Director of GREAT Smart Cities Center
The Hong Kong University of Science and Technology

ABSTRACT:

This study develops stochastic formulations for transit network design under demand uncertainty. We utilize the concept of service reliability to confine the stochastic demands into a bounded uncertainty set that the transit services are designed to cover. To evaluate the outcomes of the uncertainty set, flexible services, such as third party contract services are introduced to carry the demand overflow that exceeds the capacity of transit services. The problem aims to find the optimal level of service reliability that minimizes the combined transit services cost, flexible services cost and passenger cost. A two-phase stochastic program is formulated in which scheduled commitments (e.g. line alignment and frequencies) are determined in phase-1 for a specified level of service reliability, whereas the third party contract services are determined in phase-2 depending on the demand realization to capture the cost of demand overflow beyond the level of service reliability specified. The transit network and passenger flow patterns are studied under system optimal (SO) and user equilibrium (UE) flows. Illustrative examples are developed to demonstrate the solution performance and advantages of utilizing the two-phase formulation. This formulation approach is applicable for both transit network design and more general service or logistics network design.

SPEAKER BIO:

Professor Hong K. LO is Department Head and Chair Professor of Civil and Environmental Engineering and Director of GREAT Smart Cities Center of the Hong Kong University of Science and Technology. His expertise includes dynamic transportation system modeling, traffic control, network reliability, and public transportation analysis. He has published extensively in the transportation literature and was selected as one of the Most Cited Researchers in Civil Engineering by Elsevier in 2016. Professor Lo is very active in the transportation community, for instance, elected as Convener of the International Scientific Committee of the conference series Advanced Systems for Public Transportation (CASPT), serves as Founding Editor-in-Chief of Transportmetrica B: Transport Dynamics, Managing Editor of Journal of Intelligent Transportation Systems, and on the editorial boards of many international journals, including Transportation Research Part B, International Journal of Sustainable Transportation, ASCE Journal of Urban Planning and Development, among others. Locally, he served on the Transport Advisory Committee (TAC) advising the Chief Executive in Council of the Hong Kong government, Hong Kong-Zhuhai-Macau Bridge Feasibility Study Expert Panel, Vice-President of the Hong Kong Society for Transportation Studies, Convener of Railway Objections Hearing Panel, etc. Recently, he has been appointed as a Member of the Independent Review Committee on Hong Kong’s Franchised Bus Service. Professor Lo was awarded the prestigious triennial World Conference on Transportation Research (WCTR) Prize in 2001, Eastern Asia Society for Transportation Studies (EASTS) Outstanding Paper Award in 2003, and Hong Kong Institution of Engineers (HKIE) Transactions Prize in 2000, more recently, HKUST School of Engineering Research Excellence Award in 2014. Prof Lo has been appointed as Justice of the Peace (JP) by the Hong Kong government, and is a Fellow of The Hong Kong Institution of Engineers (HKIE), Fellow of the Chartered Institute of Logistics and Transport (CILT), Fellow of the Hong Kong Institute of Highway and Transportation (IHT), and Fellow of the Hong Kong Society for Transportation Studies.