1. Postdoctoral Scholar, Safe Transportation Research and Education Center, Univ. of California, 2614 Dwight Way, Berkeley, CA 94720; formerly, M.S. in Civil and Environmental Engineering, Dept. of Civil and Environmental Engineering, Univ. of California, 116 McLaughlin Hall, Berkeley, CA 94720 (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Univ. of California, Berkeley, 110 McLaughlin Hall, Berkeley, CA 94720.