Test field real laboratory cycle path

The "Reallabor Radbahn" test field is located in Berlin Kreuzberg, along Skalitzer Straße. The area previously used as a parking lot has been transformed into a new urban green space. Here, slow mobility meets nature and citizens are offered a covered linear park.



STRUCTURE: THE ISLANDS AND THE GREEN BAND

Removing the parking spaces frees up space for pedestrians and cyclists and is the first step towards creating two "islands" connected by a green ribbon. The concept of the islands was developed in a participatory process and is intended to facilitate various activities. Sitting, playing, art or events, for example, are located in the interaction island and make this island a place for socializing and meeting. The second island, the so-called cycling island, serves the functional needs of cyclists with equipment specially designed for them. Together with the intensively planted green belt, a linear park is created that provides an urban nature experience for cyclists and other users as well as a refuge for birds, small mammals and insects.



A RESPONSE TO CLIMATE CHALLENGES TODAY AND IN THE FUTURE

In the context of the climate crisis in the middle of the Berlin metropolis, the highly urbanized environment poses new challenges to which the project responds with a future-oriented vision that minimizes the use of new building materials, limits demolition, reduces the heat island effect and promotes rainwater harvesting. Key project strategies include:



Unsealing: The first measure was the removal of the pavement, which unsealed more than 250m2 of former parking lot space. Paving with open joints was also chosen in the areas where there are still paved surfaces, which promotes rainwater infiltration.



Reuse: All surfaces were created by reusing existing materials. On the interaction island, the red concrete blocks of the parking spaces were re-laid with grit joints. On the cycle island, the concrete blocks were laid alternately with new red bricks, creating a shimmering surface. The removed granite kerbs were cut into blocks and used as stepping stones in the vegetation.



Water management: The planting areas are designed to retain rainwater to mitigate the microclimate and support plant growth during dry periods. Due to the roof effect of the viaduct and the high risk of drought, the terrain was modeled in such a way that rainwater is directed into the troughed areas under the roof. In addition, a filter bed was installed in collaboration with the TU Berlin, which uses plants and substrates to clean the available rainwater from the viaduct. The quality of this filtered water is currently being monitored and examined to determine whether it is suitable for irrigation.



Hardy plants: 90 shrubs and over 4000 perennials and grasses have been planted on the test field, many of them Mediterranean and climate-resistant. The plant selection, together with the soil and rain management, will lead to a durable and resistant planting that can withstand extreme climatic events. To this end, the soil was produced using various techniques and substrates, creating a mosaic of 8 different situations. The diverse climatic and geological conditions, which vary in terms of solar radiation, substrate thickness, moisture and water permeability, thus create a habitat for various plants and animal species.



Intelligent infrastructure: Interactive objects such as benches, sound installations and information systems lead to the appropriation of public space. The Radbahn is not just an urban renewal project, but a vision that combines mobility, ecology and sociality in an innovative space.

Infrastructure and mobility awardGerman Landscape Architecture Award 2025

Jury verdict:
In order to adapt our city centres to the consequences of climate change, a transformation towards green-blue-coloured infrastructures is required. This applies in particular to our urban traffic areas.

The Reallabor Radbahn project has succeeded in reappropriating urban space on a test field in the middle of the Berlin metropolis: on a 200 metre long section below the elevated railway viaduct in Kreuzberg - as an experimental site and catalyst. Car parks were removed and space was created for cyclists and pedestrians, as well as planting areas. The jury particularly praised the format of the real-world laboratory and the exemplary negotiation processes in the conscious handling of existing everyday urban spaces, in which the existing traffic space was further developed in terms of urban climate, social aspects and as a usable open space. This format can serve as a model for the socially controversial, yet urgently necessary transformation and adaptation of our traffic and everyday spaces.

The design language of the equipment elements used is convincing due to its colourfulness and freshness.

The Radbahn real-world laboratory shows us that we need more space and courage for real experiments in order to develop areas for increasing climate resilience.