1. Key Laboratory of Road and Traffic Engineering, Ministry of Education, Tongji University, 4800 Cao'an Road, Jiading District, Shanghai 201804, China
2. Department of Civil and Environmental Engineering, University of Wisconsin, Milwaukee, P.O. Box 784, Milwaukee, WI 53211
3. College of Transportation Engineering, Shanghai Maritime University, 1550 Haigang Avenue, Shanghai 201306, China.
4. Department of Civil Engineering and Mechanics, University of Wisconsin, Milwaukee, P.O. Box 784, Milwaukee, WI 53211