1. School of Civil Engineering and Transportation, South China University of Technology, Guangzhou, P.R. China;
2. Department of Civil Engineering, The University of Hong Kong, Hong Kong, P.R. China;
3. School of Traffic and Transportation Engineering, Urban Transport Research Center, Central South University, Changsha, Hunan, P.R. China;
4. General Courses Department, Military Transportation University, Tianjin, P.R. China;
5. Department of Automation, Tsinghua University, Beijing, P.R. China