1. Transportation Engineer, California Dept. of Transportation, 5900 Folsom Blvd., MS-5, Sacramento, CA 95819 (corresponding author).
2. Senior Engineer, Applied Research Associates, Inc., 100 Trade Center Dr., Suite 200, Champaign, IL 61820.
3. Principal Engineer, Applied Research Associates, Inc., 100 Trade Center Dr., Suite 200, Champaign, IL 61820.
4. Anthony Gill Chair Professor, Dept. of Civil and Environmental Engineering, Univ. of Pittsburgh, 3700 O’Hara St., 703 Benedum Hall, Pittsburgh, PA 15261.