1. Assistant Professor, Dept. of Civil Engineering, Montana State Univ., P. O. Box 173900, Bozeman, MT 59717.
2. Research Assistant, Dept. of Civil Engineering, Bradley Univ., 1501 West Bradley Ave., Peoria, IL 61625.
3. Associate Professor, Virginia Tech. Transportation Institute (VTTI), 3500 Transportation Research Plaza (0536), Blacksburg, VA 24061.