1. Ph.D. Candidate, School of Civil Engineering, Beijing Jiaotong Univ., No. 3 Shangyuancun, Haidian District, Beijing 100044, China.
2. Professor, School of Civil Engineering, Beijing Jiaotong Univ., No. 3 Shangyuancun, Haidian District, Beijing 100044, China (corresponding author).
3. Researcher, Research Institute of Highway, Ministry of Transport, No. 8 West Tucheng Rd., Haidian District, Beijing 100088, China.
4. Jiangxi Traffic Design Institute, No. 657, Jinggangshan Avenue, Qingyunpu District, Nanchang 330052, China.
5. Researcher, Railway Engineering Research Institute, China Academy of Railway Sciences Corporation Limited, No. 2 Daliushu Rd., Haidian District, Beijing 100081, China.