1. Research Assistant, Traffic Operations and Safety (TOPS) Laboratory, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin–Madison.
2. Scientist, Traffic Operations and Safety (TOPS) Laboratory, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin–Madison.
3. Managing Director, Traffic Operations and Safety (TOPS) Laboratory, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin–Madison.
4. Vilas Distinguished Achievement Professor, Traffic Operations and Safety (TOPS) Laboratory, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin–Madison.
5. Arthur F. Hawnn Professor, Traffic Operations and Safety (TOPS) Laboratory, Dept. of Civil and Environmental Engineering, Univ. of Wisconsin–Madison.