1. Jiangsu Key Laboratory of Urban ITS, Southeast University, 2 Si-Pai Lou, Nanjing, Jiangsu 210096, China
2. Transportation Engineering and Infrastructure Systems, Department of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907, USA
3. College of Civil and Transportation Engineering, Hohai University, 1 Xikang Road, Nanjing, Jiangsu 210098, China