1. Associate Research Engineer, Texas Transportation Institute, Texas A&M Univ., 3135 TAMU, College Station, TX 77843-3135 (corresponding author).
2. Senior Research Engineer, Texas Transportation Institute, Texas A&M Univ., 3135 TAMU, College Station, TX 77843-3135.
3. Assistant Research Engineer, Texas Transportation Institute, Texas A&M Univ., 3135 TAMU, College Station, TX 77843-3135.