1. School of Transportation and Logistics, Southwest Jiaotong University, Chengdu, Sichuan 610031, China
2. National United Engineering Laboratory of Integrated and Intelligent Transportation, Southwest Jiaotong University, Chengdu, Sichuan 610031, China
3. Traffic and Transportation Engineering Experiment and Comprehensive Innovation Center, Southwest Jiaotong University, Chengdu, Sichuan 610031, China