1. Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
2. Department of Logistics and Maritime Studies, The Hong Kong Polytechnic University, Hong Kong, China
3. School of Traffic and Transportation, Beijing Jiaotong University, Beijing, China
4. School of Transportation, Southeast University, Nanjing, China
5. Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, USA