1. Professor, School of Transportation, Southeast Univ., Nanjing 210096, China.
2. Ph.D. Candidate, School of Transportation, Southeast Univ., Nanjing 210096, China.
3. Associate Professor, Dept. of Civil and Environmental Engineering, Rutgers, State Univ. of New Jersey, Piscataway, NJ 08854 (corresponding author).
4. Associate Professor, School of Transportation, Southeast Univ., Nanjing 210096, China.