1. Ph.D. Candidate and Graduate Research Assistant, Texas A&M Transportation Institute, Texas A&M Univ. System, 3135 TAMU, CE/TTI Bldg. 508K, College Station, TX 77843 (corresponding author).
2. Lecturer, School of Engineering and Applied Science, Aston Univ., MB153A, Aston Triangle, Birmingham B4 7ET, U.K.
3. M.S. Candidate and Graduate Research Assistant, Texas A&M Transportation Institute, Texas A&M Univ. System, 3135 TAMU, CE/TTI Bldg. 508K, College Station, TX 77843.
4. Associate Research Engineer, Texas A&M Transportation Institute, Texas A&M Univ. System, 3135 TAMU, CE/TTI Bldg. 503C, College Station, TX 77843.
5. Professor, Fred J. Benson Chair, Zachry Dept. of Civil Engineering, Texas A&M Univ., 3136 TAMU, CE/TTI Bldg. 503A, College Station, TX 77843.