1. Ph.D. Candidate, Dept. of Civil and Environmental Engineering, Univ. of Maryland, 1173 Glenn L. Martin Hall, College Park, MD 20742 (corresponding author).
2. Professor, Dept. of Civil and Environmental Engineering, Univ. of Maryland, 1173 Glenn L. Martin Hall, College Park, MD 20742.
3. Assistant Division Chief, Office of Traffic and Safety, Maryland State Highway Administration, 7491 Connelley Dr., Hanover, MD 21076.