1. Project Engineer, MACTEC Engineering and Consulting, Inc., 12104 Indian Creek Court, Suite A, Beltsville, MD 20705.
2. Director of Center for Transportation Infrastructure Systems, Univ. of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968-0516 (corresponding author).
3. Research Engineer, Materials and Pavement Division, Texas Transportation Institute, Texas A&M Univ. System, College Station, TX 77843-313.