1. Assistant Transportation Researcher, Texas A&M Transportation Institute, Texas A&M Univ. System, College Station, TX 77843.
2. Assistant Professor, Mechanical and Aeronautical Engineering, Clarkson Univ., Potsdam, NY 13699.
3. Associate Professor, Civil Engineering, Univ. of Nebraska-Lincoln, Lincoln, NE 68583 (corresponding author).
4. Professor, Mechanical and Materials Engineering, Univ. of Nebraska-Lincoln, Lincoln, NE 68588.