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