1. Graduate Engineer, Fugro Roadware, Inc., 8613 Cross Park Drive, Austin, TX 78754 (Corresponding author), e-mail: tr_rafi@yahoo.com
2. Professor and Regent's Lecturer, Department of Civil Engineering, Univ. of New Mexico, MSC01-1070, Albuquerque, NM 87131-0001, e-mail: tarefder@unm.edu