1. Jiangsu Key Laboratory of Urban ITS, Jiangsu Province Collaborative Innovation Center of Modern Urban Traffic Technologies and Jiangsu Province Collaborative Innovation Center for Technology and Application of Internet of Things, School of Transportation, Southeast University, Nanjing 210096, China
2. School of Engineering, Tibet University, Lhasa, Tibet 850000, China
3. Department of Civil & Environmental Engineering, University of Wisconsin-Madison, 1221 Engineering Hall, 1415 Engineering Drive, Madison, WI 53706, USA