1. Transportation Engineer, Vanasse Hangen Brustlin, Inc., 8300 Boone Blvd., Suite 700, Vienna, VA 22182-2626.
2. Director, Center for Sustainable Mobility, Virginia Tech Transportation Institute; and Professor, The Charles Via, Jr. Dept. of Civil and Environmental Engineering, Virginia Tech., 3500 Transportation Research Plaza, Blacksburg, VA 24061 (corresponding author).
3. Assistant Professor, Ain-Shams Univ., Cairo, Egypt; and Senior Research Associate, Center for Sustainable Mobility, Virginia Tech. Transportation Institute, Virginia Tech., 3500 Transportation Research Plaza, Blacksburg, VA 24061.