1. School of Engineering, and Transportation Research Center, University of Vermont, Farrell Hall 114, 210 Colchester Avenue, Burlington, VT 05405-0303, USA
2. Department of City and Regional Planning, University of California, Berkeley, 228 Wurster Hall, Room 1850, Berkeley, CA 94720-1850, USA
3. Institute of Urban and Regional Development, University of California, Berkeley, 316 Wurster Hall, Room 1870, Berkeley, CA 94720-1870, USA
4. Department of Civil and Environmental Engineering, Arizona State University, Room ECG252, Tempe, AZ 85287-5306, USA