1. Postdoctoral Research Associate, Dept. of Civil and Environmental Engineering, Virginia Polytechnic Institute and State Univ., 301N Patton Hall, Blacksburg, VA 24061 (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Virginia Polytechnic Institute and State Univ., 301N Patton Hall, Blacksburg, VA 24061.
3. Senior Research Scientist, Virginia Center for Transportation Innovation and Research, Virginia Dept. of Transportation, 530 Edgemont Rd., Charlottesville, VA 22903.