1. Associate Professor, MOE Key Laboratory for Transportation Complex Systems Theory and Technology, School of Traffic and Transportation, Beijing Jiaotong Univ., 100044 Beijing, P.R. China (corresponding author).
2. Professor, Dept. of Transportation Studies, Texas Southern Univ., 3100 Cleburne Ave., Houston, TX 77004; and Yangtzi River Scholar, Beijing Jiaotong Univ., 100044 Beijing, P.R. China.
3. Traffic Engineer, Chongqing Transport Planning Institute, 237 Diance Cun, Jiangbei District, 400020 Chongqing, P.R. China.