1. Assistant Professor, Dept. of Civil Engineering, North Carolina A&T State Univ., 447 McNair Hall, 1601 E. Market St., Greensboro, NC 27411 (corresponding author).
2. Founder Professor of Engineering and Director of 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.