1. Research Assistant, Dept. of Civil, Construction, and Environmental Engineering, Iowa State Univ., Ames, IA.
2. Professor and Director, Dept. of Civil, Construction, and Environmental Engineering, Program for Sustainable Pavement Engineering and Research, Iowa State Univ., Ames, IA.
3. Associate Director, Program for Sustainable Pavement Engineering and Research, Institute for Transportation, Iowa State Univ., Ames, IA.
4. Transportation Practice Area Leader, Michigan Tech Research Institute, Ann Arbor, MI.
5. Vice President, Applied Pavement Technology, Inc., Urbana, IL.