1. Marie Curie Postgraduate Research Fellow, Nottingham Transportation Engineering Centre, University of Nottingham Faculty of Engineering, Univ. of Nottingham, University Park, Nottingham NG7 2RD, U.K. (corresponding author).
2. Senior Research Associate, Center for Sustainable Transportation Infrastructure, Virginia Tech Transportation Institute, 3500 Transportation Research Plaza, Blacksburg, VA 24061.
3. Director, Center for Sustainable Transportation Infrastructure, Virginia Tech Transportation Institute, Virginia Tech, Blacksburg, VA 24061-0105; Professor, Charles Via, Jr. Dept. of Civil and Environmental Engineering, 3500 Transportation Research Plaza, Virginia Tech, Blacksburg, VA 24061-0105.
4. Senior Research Scientist, Virginia Center for Transportation Innovation and Research, 530 Edgemont Rd., Charlottesville, VA 22903.