1. Ph.D. Candidate, School of Transportation, Southeast Univ., 79 Suyuan Ave., Jiangning District, Nanjing, Jiangsu 211189, China.
2. Associate Professor, School of Transportation, Southeast Univ., 79 Suyuan Ave., Jiangning District, Nanjing, Jiangsu 211189, China (corresponding author).
3. Associate Professor, School of Architecture and Transportation Engineering, Guilin Univ. of Electronic Technology, No. 1 Jinji Rd., Guilin, Guangxi 541004, China.