1. Chongqing Transport Planning Institute, Chongqing 401147, China
2. Chongqing Key Lab of Traffic System and Safety in Mountain Cities, Chongqing 400074, China
3. College of Traffic and Transportation, Chongqing Jiaotong University, Chongqing 400074, China
4. Tianjin Transportation Research Institute, Tianjin 300074, China