Administrative Court of Gelsenkirchen (VG): When properties are directly connected to federal highways, road safety takes precedence over additional residential use in open countryside areas.

A building permit for the conversion of a building in open countryside was rightly refused because direct connection to federal highways could impair traffic flow on an adjacent federal motorway.

The legal background – conversion in open countryside and connection to federal highways

The conversion of buildings in open countryside is one of the classic areas of conflict in building and road law. Whilst § 35 Building Code (BauGB) generally permits only privileged projects such as agricultural use, residential use faces strict limitations. In addition, there is a further hurdle for properties with direct connection to federal highways. § 9 Federal Roads Act (FStrG) requires in such cases the consent of the road construction authority if construction modifications or changes in use trigger additional access traffic. This consent may be refused if the safety or smooth flow of traffic would be impaired. Thus, the focus is not only on hazard prevention in the strict sense, but also on unimpeded traffic flow.

What was at issue here?

In the proceedings decided before the Administrative Court of Gelsenkirchen (Judgment of 9 September 2025 – 6 K 675/24), the owner of a 16,500 m² farm property wanted to convert an old barn into a further residential unit. The property is located in open countryside in a landscape conservation area and is directly connected to federal highway B xxx via a shared access road. There are already two approved residential units on the property.

The claimant argued that traffic congestion on the B xxx was below average at around 7,400 vehicles per day and that the access road was not in a critical curve location. In addition, he pointed to the high demand for housing and family reasons: his son and family were to move into the newly created residential unit, also to ensure long-term care for his parents. As a compromise, he proposed widening the access and introducing a "right-turn-right-turn system" for entry and exit.

By contrast, the competent road construction authority refused the required consent. It referred to the proximity of a curve, the crossing pedestrian and cycle path, and an accident already recorded in the area in question. The creation of an additional residential unit with associated increased traffic alone increased the hazard potential and impaired traffic flow on the federal highway.

The court's decision

The administrative court dismissed the action and confirmed the road construction authority's refusal. The key point was that a change in use from a barn to residential purposes would trigger additional origin and destination traffic. In the court's view, an increase in the use of the access of approximately 50% was to be expected – an increase that could no longer be regarded as marginal.

The judges clarified that § 9 para. 3 FStrG does not serve only to prevent concrete accident hazards. Even a mere impairment of "smooth traffic flow" justifies refusal. Federal highways are designed for non-local traffic at higher speeds and can only fulfil their function if additional disruptions are largely excluded. The mere possibility that vehicles entering or exiting due to direct connection to federal highways could slow down traffic flow is sufficient.

The court attached particular importance to local conditions: the access is located near a curve, is not visible until late, and is additionally crossed by a pedestrian and cycle path. This increases the probability of conflict-prone traffic situations, for example when a vehicle turning in must brake in order to allow cyclists to pass. The proposed compromises such as a widened access or a one-way traffic system could not completely allay these concerns.

Furthermore, the court emphasized that personal considerations such as family housing needs or care requirements are of no significance for the assessment under building planning and road law. A building permit has effect in relation to the property and is unlimited in time, so that it also benefits future owners. An argument based on individual life circumstances is therefore not suitable for overriding the road law requirements.

Significance for practice

The judgment of the Administrative Court of Gelsenkirchen once again illustrates the high requirements for building projects in open countryside with direct connection to federal highways. Even minor additional traffic movements can justify refusal under § 9 FStrG if the local traffic situation is already fraught with risk. What matters is not the concrete accident statistics, but the possibility evident when directly connected to federal highways that traffic flow could be disturbed or traffic participants could be endangered.

For developers, this means: early examination of the road law framework conditions is essential for direct connection to federal highways. Those planning a conversion should not rely solely on confirmation of agricultural or nature conservation law compliance, but should consider the road traffic law aspect from the outset. Compromise solutions such as access widening can be helpful, but do not replace the fundamental road law assessment.

Our recommendation

Owners of properties in open countryside with direct connection to federal highways should seek legal advice early from the experts in administrative law at AVANTCORE Rechtsanwälte in Stuttgart before submitting preliminary building inquiries or planning conversions. Only in this way can it be realistically assessed whether there are prospects of obtaining the road construction authority's consent. Personal reasons – understandable as they may be in an individual case – carry no weight in this procedure. Anyone wishing to plan with legal certainty must therefore take into account the road law hurdles of § 9 FStrG from the outset.