1. Postdoctoral Research Associate, The Via Dept. of Civil and Environmental Engineering, Virginia Polytechnic Institute and State Univ., Blacksburg, VA 24061 (corresponding author).
2. Professor, The Via Dept. of Civil and Environmental Engineering, Virginia Polytechnic Institute and State Univ., Blacksburg, VA 24061.
3. Postdoctoral Research Associate, Virginia Tech Transportation Institute, 3500 Transportation Research Dr., Blacksburg, VA 24061.
4. Senior Research Associate, Virginia Tech Transportation Institute, 3500 Transportation Research Dr., Blacksburg, VA 24061.