1. School of Transportation and Logistics, Southwest Jiaotong University, Chengdu 610031, P. R. China
2. National United Engineering Laboratory of Integrated and Intelligent Transportation, Southwest Jiaotong University, Chengdu 610031, P. R. China
3. State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026, P. R. China
4. Collaborative Innovation Center for Urban Public Safety, Hefei 230026, P. R. China
5. Faculty of Geosciences and Environmental Engineering, State-Province Joint Engineering Laboratory of Spatial, Information Technology of High-Speed Rail Safety, Southwest Jiaotong University, Chengdu 610031, P. R. China