1. Professor, College of Traffic and Transportation, Chongqing Jiaotong Univ., Chongqing 400074, China (corresponding author).
2. Postgraduate, College of Traffic and Transportation, Chongqing Jiaotong Univ., Chongqing 400074, China.
3. Assistant Engineer, College of Traffic and Transportation, Chongqing Jiaotong Univ., Chongqing 400074, China.
4. Professor, College of Traffic and Transportation, Chongqing Jiaotong Univ., Chongqing 400074, China.