1. The Founder Professor of Engineering and Director of the Illinois Center for Transportation; Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 N. Mathews Ave., MC-250, Urbana, IL 61801 (corresponding author).
2. Assistant Professor, Dept. of Civil and Environmental Engineering, Univ. of Texas at San Antonio, BSE Bldg. 1.322, One UTSA Circle, San Antonio, TX 78429.
3. Graduate Research Assistant, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 N. Mathews Ave., MC-250, Urbana, IL 61801.
4. Associate Professor, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205 N. Mathews Ave., MC-250, Urbana, IL 61801.