Patterns of Current Urban Expansion in Germany: A Comparative Analysis of Five City Regions

Following a period of reurbanization, recent studies have drawn attention to the resurgence of urban expansion processes in German metropolitan regions. However, empirical research demonstrates that the dynamics of urban expansion exhibit significant geographical variation in response to multiple determinants, including economic conditions, governance arrangements, and population change. Against this background, the present article examines processes of urban expansion in five major German city regions: Berlin, Hamburg, Munich, Frankfurt am Main, and Freiburg im Breisgau. For each case study, it undertook a GIS analysis of a particular focus area (transect) of the respective city regions where large greenfield projects are currently planned. This analysis reveals that development dynamics differ significantly, both between and within these five case studies, in terms of scale and building typologies. While urban expansion in some areas appears to be aligned with sustainability demands, with development becoming increasingly dense and compact, other areas continue to rely heavily on single-family housing. Drawing upon spatial data from the German census, this article provides a detailed account of the heterogeneity of urban expansion patterns in Germany with respect to population development and housing stock composition. Employing urban sprawl and material efficiency metrics, as well as a measure of the functional integration of mobility infrastructures, the observed patterns are assessed as to whether they meet sustainability criteria.