1. School of Transportation Science and Engineering, Beihang University, Beijing 100191, China
2. School of Civil and Environmental Engineering, Harbin Institute of Technology, Shenzhen 518055, China
3. School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan 430070, China
4. Department of Civil and Environmental Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK