1. Graduate Research Assistant, Dept. of Civil, Construction, and Environmental Engineering, Institute for Transportation, Center for Transportation Research and Education, Iowa State Univ., Ames, 2711 South Loop Dr., Suite 4700, IA 50010.
2. Associate Professor, Dept. of Civil, Construction, and Environmental Engineering, Insitute for Transportation, Center for Transportation Research and Education, Iowa State Univ., 2711 South Loop Dr., Suite 4700, Ames, IA 50010 (corresponding author).
3. Graduate Research Assistant, Dept. of Statistics and Dept. of Agronomy, Institute for Transportation, Center for Transportation Research and Education, Iowa State Univ., 2711 South Loop Dr., Suite 4700, Ames, IA 50010.
4. Safety Circuit Rider, Institute for Transportation, Center for Transportation Research and Education, Iowa State Univ., 2711 South Loop Dr., Suite 4700, Ames, IA 50010.
5. Traffic Operations Engineer, Iowa Dept. of Transportation, 800 Lincoln Way, Ames, IA 50010.