1. Professor of Engineering, Planning Development Dept., Chongqing Transport Planning and Technology Development Center, Chongqing 40000, PR China.
2. Research Assistant, School of Civil Engineering, Chongqing Jiaotong Univ., Chongqing 400074, PR China.
3. Research Assistant, School of Civil Engineering, Southwest Jiaotong Univ., Chengdu 610031, PR China.
4. Ph.D. Candidate, School of Civil Engineering, Chongqing Jiaotong Univ., Chongqing 400074, PR China.
5. Ph.D. Candidate, School of Civil Engineering, Southwest Jiaotong Univ., Chengdu 610031, PR China (corresponding author).