Form follows policy – Tracing the effects of sustainable land policies on urban form

• Applicant: Dr.-Ing. Mathias Jehling, Ph.D.
• Subject Area: City Planning, Spatial Planning, Transportation and Infrastructure Planning, Landscape Planning ; Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography ; Political Science
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 512639122

Societal debates and research are increasingly questioning current land policies. As ecological consequences of urban growth become apparent, the goal of sustainable urbanisation demands for fundamental changes in how we plan and manage urban land. While sustainability oriented land policies have been introduced recently, little is known about their potential to bring the required changes. This lack of knowledge points to the need to better understand effects of land policies on the development of cities and regions. Therefore, causal effects of policies on physical urban form need to be traced and changes of long-term and stability oriented land policies need to be analysed. Addressing this need, an innovative approach is proposed that combines data-driven spatial analysis and a neo-institutional perspective on practices of land policy. It addresses methodological challenges for an empirical analysis of causal relations within complex physical urban structures and complex institutional arrangements in urban development. Using data-driven approaches, urban form is analysed on the level of spatial arrangements of buildings. The high level of detail of building data allows to observe the effects of land policies, such as regulations from land use planning for the use of private property. Further data is used to analyse locational effects and change over time. Data-driven approaches, such as machine learning, are applied to extensive spatial structures of city regions and to identify patterns of urban development. To gain insights on causal relations between form and policy, these spatial patterns are contrasted with respective practices of land policy. To do so, a strict research design is applied that combines complementary approaches to explanation and causation from quantitative spatial analysis and qualitative case study approaches. Based on observed correlations between form and policy, the role of actors in applying land policies is scrutinised in sub-cases. Cases of development projects are used to infer on institutional logics in urban development that explain, why specific policies were applied. Through comparing sub-cases at different points in time, development paths that hamper or enable the application of sustainable land policies are identified. To develop and test the approach, a comparative setting is required with clear variation in effect (form) and cause (policy). The research is applied to residential development of the last 30 years in a German-French cross-border area. While Germany and France follow a similar sustainability agenda, they stand for highly different systems of land policies. Tracing the effect of sustainable land policies, the proposed project seeks to advance research on land policy in methodological terms through addressing causal inference and generalisation in urban development. It therewith aims to enhance knowledge generation for policy development and assessment in land use planning and land management.

• DFG Programme: Research Grants
• International Connection: France
• Co-Investigator: Professor Dr. Thomas Hartmann
• Cooperation Partners: Privatdozentin Dr. Bénédicte Bucher; Professorin Dr. Sonia Guelton; Professor Dr. Philippe Hamman