Around 320,000 flats need to be built in Germany every year. This is the forecast for the coming years by the Federal Institute for Research on Building, Urban Affairs and Spatial Development. To enable housing projects to be completed more quickly, the legislature has passed the „Act to Accelerate Housing Construction“ – the ‘construction turbo’. The Act provides for exemptions from local development plans, the permission of residential use in unplanned inner-city areas, and deviations via a temporary experimental clause. However, none of this can be implemented unless the local authority gives its express consent on a case-by-case basis. It is the local authority that decides whether and how the ‘Bau-Turbo’ is applied locally. This opens up new opportunities for local authorities to actively shape their housing policy. Conversely, however, this also means that clear objectives, as well as regulations governing responsibilities and procedures, must be in place.

In practice, the ‘Bau-Turbo’ plays a significant role, particularly in infill development, the conversion of existing buildings and the development of vacant plots. Typical examples include adding extra storeys to existing residential areas or converting vacant office buildings into housing. In such cases, the ‘construction fast-track’ can help to make better use of existing structures and shorten planning approval processes without always having to carry out a full town planning procedure.

Overall, the ‘construction fast-track’ scheme broadens the existing legal scope. This makes it easier to grant exemptions from the provisions of a local development plan and to extend these exemptions to cover several comparable projects. In unplanned inner-city areas, residential buildings may be approved even if they do not fully blend in with the existing built environment, provided that the overall urban planning rationale is upheld. The experimental clause, which is valid until the end of 2030, is particularly far-reaching. It allows local authorities to deviate from numerous provisions of the Building Code in housing projects, provided that neighbours’ interests are taken into account. For example, local authorities can trial alternative mobility concepts, reduced parking space requirements or new forms of mixed-use development in new neighbourhoods.

All these concessions are subject to the local authority’s approval of the project. If approval is not granted, the project remains subject to the standard planning regulations, with the usual assessment criteria and deadlines. Approval is therefore not merely a formal formality, but the key factor in ensuring that the ‘construction fast-track’ is applied at all.

The division of roles in the process is clearly defined: the planning authority assesses whether the project meets the legal requirements – for example, regarding setbacks, fire safety, parking spaces or protection against environmental pollution. The local authority decides whether the project fits in with its urban planning concepts and development objectives. Its approval is an independent, politically influenced decision taken within the framework of planning authority, which is protected under constitutional law. It must be guided by local objectives, be based on clear and comprehensible grounds, and must not appear arbitrary if it is to stand up to challenge by the developer and in court.

The Mannheim Administrative Court emphasised this position of the local authority in a judgement dated 6 November 2025 (Case No. 5 S 695/24). The case concerned a block of flats in Karlsruhe that was to be built under the ‘Bau-Turbo’ scheme. Although the building control authority assessed the application under this scheme, the project failed because the city did not grant its approval. The court made it clear that, without the municipality’s express consent, the ‘Bau-Turbo’ measures do not take effect. The local authority thus retains control over residential development within its area.

The ‘construction fast-track’ also increases the organisational demands on the local authority. The three-month deadline is particularly relevant: if the planning authority requests the local authority’s approval, the latter must make a decision within three months and notify the authority of its decision. If it fails to respond, consent is deemed to have been granted – with the result that the local authority loses its right to have a say and can no longer impose any substantive requirements. Given limited staffing resources, this requires clear internal procedures and arrangements regarding responsibilities.

However, the law does not specify which body is to grant approval. Whether the mayor, a committee or the local council is responsible is left to the discretion of the local authority. Given the far-reaching nature of the decision – the exercise of planning authority and the setting of a long-term course for urban development – local authorities should clearly define the relevant responsibilities in their main statutes, the plans for the allocation of duties or internal service instructions. Formal errors in the approval procedure can seriously undermine the legal certainty of subsequent decisions.

In terms of content, approval does not have to be an unconditional „yes“. The local authority may also attach conditions or requirements to its approval, such as quotas for social housing, requirements regarding design and use, or contributions to social and technical infrastructure. In this way, the approval itself becomes a policy instrument. It makes sense to define criteria and typical conditions in advance and to secure political legitimacy for them, so that decisions can be made consistently and transparently in similar cases.