1. Ph.D. Candidate, College of Civil Engineering and Architecture, Zhejiang Univ., Hangzhou 310058, P.R. China; Faculty of Civil Engineering and Geosciences, Dept. of Transport and Planning, Delft Univ. of Technology, Delft 2628 CN, Netherlands.
2. Ph.D. Candidate, College of Civil Engineering and Architecture, Zhejiang Univ., Hangzhou 310058, P.R. China.
3. Master, College of Civil Engineering and Architecture, Zhejiang Univ., Hangzhou 310058, P.R. China.
4. Associate Professor, College of Civil Engineering and Architecture, Zhejiang Univ., Hangzhou 310058, P.R. China (corresponding author).