Greenbelts in Germany's regional plans—An effective growth management policy?

•First detailed review of the performance of greenbelt planning in Germany.•Use of geo-referenced data on the geography of greenbelt planning.•GIS-based empirical evidence on the output and outcome of greenbelt planning.•Contribution to cross-national comparative studies on growth management policies. Greenbelts are the best-known growth management policies in Germany. As part of its regional plans, they attempt to keep undeveloped areas permanently open, thus avoiding sprawling, i.e., land consumptive forms of urban development. However, the effectiveness of such land use designations in terms of guiding and limiting urban growth has rarely been the subject of in-depth research. This is the first study to present a GIS-based analysis of the restrictiveness of greenbelt designations in Germany and their impact on urban spatial structure and land use. The key question is to what extent greenbelts actually limit urban growth, both individually and in combination with other policy instruments of open space conservation. Key indicators are the tightness of greenbelts around urban areas and their effect on the regional patterns of urban growth, measured by the increase of built-up areas in contained (the inbound area) and uncontained (outside the greenbelt) communities. Our empirical results for four case study regions suggest that greenbelts are an effective means of open space preservation. The impact of greenbelts on spatial urban structure, however, seems to be limited due to a relatively low degree of tightness.