Abstract:  German metropolitan regions experience simultaneous reurbanisation in core cities and intensified suburbanisation in surrounding municipalities. Given limited peripheral administrative resources and complex land availability, a fundamental question arises: Who actually steers urban development in suburban areas? While the Federal Building Code requires formal urban land‑use planning, pivotal preliminary decisions on location, scale, density, and actors occur informally beforehand. This study examines how these early decision‑making processes in suburban residential area development are shaped by informal negotiations among public and private actors. The theoretical framework integrates Kingdon’s multiple streams framework, Sorensen’s critical junctures, Sydow’s path dependency theory, real estate project logic, Flyvbjerg’s concepts of rationality and power, and Heurkens’ typology of private‑led urban development. This study combines 12 overarching expert interviews with seven in-depth case studies in the Hamburg metropolitan region, capturing perspectives from municipal stakeholders, private urban planning consultancies, district administrations, and project developers. Analyzed alongside official planning documents through qualitative content analysis, the findings reveal a distinct preliminary phase dominated by confidential, small-scale negotiations among mayors, landowners, and developers. These processes predefine core project parameters, creating path dependencies that significantly limit subsequent formal planning flexibility and public input, visualised in a multi-level, phase‑based actor model. Ultimately, the findings highlight structural asymmetries that challenge systematic public steering and sustainable development in suburban areas. The study concludes with recommendations for a more proactive municipal land policy, enhanced institutional capacity-building, and supportive regional frameworks to secure long-term environmental and spatial objectives.

Keywords:  informal negotiations; land availability; path dependency; preliminary decision-making; suburban development

Published:   14 September 2026

Issue:   Vol 11 (2026): Suburban Development and City Extensions (In Progress)