1. Associate Professor, School of Transportation Engineering, Southeast Univ., Nanjing 211189, China.
2. Research Assistant, Dept. of Civil and Environmental Engineering, Washington State Univ., Pullman, WA 99163.
3. Associate Professor, Rail Transportation Engineering, Pennsylvania State Univ., Altoona, PA 16801 (corresponding author).
4. Assistant Professor, Dept. of Civil, Coastal, and Environmental Engineering, Univ. of South Alabama, Mobile, AL 36688.
5. Professor, Dept. of Civil and Environmental Engineering, Washington State Univ., Pullman, WA 99163.
6. Irma Louise Rush Stewart Distinguished Professor, Dept. of Civil and Environmental Engineering, Louisiana Transportation Research Center, Louisiana State Univ., Baton Rouge, LA 70803.