1. School of Traffic and Transportation, Lanzhou Jiaotong University, Anning West Rd. #88, Lanzhou 730070, China
2. Department of Transportation Engineering, Tongji University, Caoan Rd. #4800, Shanghai 201804, China
3. School of Civil Engineering and Mechanics, Huazhong University of Science and Technology, Luoyu Rd. #1037, Wuhan 430074, China
4. College of Traffic and Transportation, Chongqing Jiaotong University, XueFu Rd. #66 Nan’an District, ChongQing 400074, China