| 2009- | Visiting Professor, Centre for Advanced Spatial Analysis, University College London |
| 2001- | Partner, Spiekermann & Wegener, Urban and Regional Research, Dortmund |
| 2000-2003 | Executive Director, Institute of Spatial Planning, University of Dortmund |
| 1996-2003 | Professor, Faculty of Spatial Planning, University of Dortmund |
| 1991 | Visiting Professor, Department of Civil Engineering, University of Gifu, Gifu, Japan |
| 1988-1989 | Professor, Department of Civil Engineering, University of Tokyo, Japan |
| 1984-2000 | Deputy Director, Institute of Spatial Planning, University of Dortmund |
| 1982 | International Institute for Applied Systems Analysis, Laxenburg, Austria |
| 1977-1984 | Project Leader, Institute of Spatial Planning, University of Dortmund |
| 1969-1976 | Research Group Leader, Battelle-Institut e.V., Frankfurt am Main |
| 1966-1969 | Teaching/Research Assistant, Faculty of Architecture, Technical
University of Berlin |
| 1964-1966 | Architectural Office O.M. Ungers, Berlin |
| 1958-1959 | Architectural Office Deigert & Yerkes, Washington, DC, USA |