1. Pavement Research Associate, Dept. of Civil and Coastal Engineering, Univ. of Florida, Gainesville, FL 32609.
2. Associate Professor, Rail Transportation Engineering, Pennsylvania State Univ., Altoona, PA 16601 (corresponding author).
3. Senior Sustainability Research Engineer, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, Urbana, IL 61801.
4. Professor, Dept. of Civil and Environmental Engineering, Louisiana Transportation Research Center, Louisiana State Univ., Baton Rouge, LA 70803