Green Mixed Bus Fleet Management Strategy
Diesel buses, a common mode of urban transit, are accountable for a sizeable portion of transport-induced air pollution. Hence, in recent years, more and more clean-energy buses are introduced to mitigate the problem. Among them, electric buses have been recognized as the cleanest, with zero tail-pipe emissions. But their deployment is limited by their short range and long charging time, hence incorporating their routing plan and charging scheduling is critical in designing the mixed bus fleet. This study develops a formulation to design the mixed bus fleet by minimizing the total overall costs of managing the fleet, including operation costs, external costs of emissions, resale and purchase costs of replacement buses. The formulation incorporates the routing and scheduling problems of bus services coordination among multiple routes. Four types of buses are considered, i.e. electric, compressed natural gas, hybrid-diesel, and diesel. The approach determines both the optimal fleet size and its composition under budget constraints. We then apply the formulation to a case study in Hong Kong. The results show that bus service coordination and mixed fleet optimization are important considerations for managing the bus fleet; both can produce considerable benefits.
Professor Hong K. LO is Head and Chair Professor of Civil and Environmental Engineering 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, with about 200 papers in conference proceedings, a dozen book chapters, and close to 180 refereed journal papers. His current SCI h-index is 32, Google Scholar h-index 43, and is recently listed as one of 150 Highly Cited Researchers in Civil Engineering by the Shanghai-Elsevier Global Ranking of Academic Subjects 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 (2015 SCI Impact Factor 2.56), 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, Journal of Advanced Transportation, ASCE Journal of Urban Planning and Development, among others. 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 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.