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Matthias Heskamp

Reallabor Radbahn

A 200-meter-long test site at the heart of Berlin: the Reallabor Radbahn project beneath the U1 viaduct on Skalitzer Strasse – between Mariannenstrasse and Oranienstrasse – is unique. From 25 April to 15 June 2024, the testing ground in Kreuzberg allows the public to experience first hand how structural changes can improve quality of life in a city like Berlin. Public space is turned into an area that is open to design between two roads with a bicycle path in the middle, which – according to the planners’ vision – could well run for 9 kilometres beneath and alongside the U1 line. Architect Matthias Heskamp is the managing director of the Reallabor Radbahn company as well as the CEO of the paper planes association. The latter developed the concept for the Reallabor Radbahn project and is now implementing it in cooperation with the Friedrichshain-Kreuzberg District Office within the framework of a funding project. We talked to Matthias Heskamp to find out more about the project, the experiences gathered during the “lab work” so far and what the Reallabor Radbahn project means for the implementation of regional and national smart city objectives.

Mr Heskamp, what moved the paper planes team to initiate the Reallabor Radbahn project? Can you tell us a bit about its history?

The bicycle path concept we developed was received surprisingly positively by the national and international public. In 2017, we created a crowdfunded book entitled The Berlin bicycle path, a vision of the future of the ecomobile city (“Radbahn Berlin, Zukunftsvisionen für die ökomobile Stadt”, German only). It focuses on the potential of any cross-section of Berlin, at the same time pointing out approaches for constructive solutions. The book also helped us gain a lot of respect from politics and administration. However, Berlin didn’t quite seem to have the foundation to simply flip the switch and build a nine-kilometre-long path. Over the course of the 2017/2018 Smart Cities Strategy Dialogue hosted by the Smart City Berlin Network and its Sustainable Mobility in Urban Neighbourhoods (“Nachhaltige Mobilität in Stadtquartieren”) expert panel we found that a regulatory sandbox with a test site of a limited size and temporary nature is the right medium to help a project get to the implementation phase. In 2019 we applied to the State of Berlin with our approach and Berlin in turn worked with us to apply to the Federation to be part of the funding programme entitled National Urban Development Projects (“Nationale Projekte des Städtebaus”, German only). And we were successful: we were awarded the contract in the autumn of 2019.

What are the most important findings from the project to date – and what could have gone more smoothly?

Due to our status as an experimental laboratory and our partnership with the Friedrichshain-Kreuzberg district, we assumed we would be able to handle lengthy approval processes more easily and move accordingly quickly from the planning to the implementation phase. That, however, turned out to be rather ambitious of us. We are currently already in a project extension phase in order to still be able to construct and evaluate the actual test site. This was preceded by four years of planning and much coordination, especially with regard to a crossroads that the funding body required we incorporate into the project. Long story short: the crossroads didn’t make it. But we were always able to score points by being agile when it came to the little things. For example the roughly 50-metre-long interactive site that we utilised in the summer of 2022 – prior to the actual construction of the 200-metre-long route. In the “Hands-on Duct” we put together a bicycle repair station, an exhibition made of recycled road signs and a light installation; sheer muscle power lights up the latter. All of the above is a perfect fit for Kreuzberg.

The 200-metre-long Reallabor Radbahn test site – which will be in active use as of 25 April – was conceived of as a “dynamic, utilisable space”: what will go on there, exactly?

The word “dynamic” is a very fitting description. The participation events taught us that cities should offer more free space that residents can use and shape creatively according to their own ideas. And that’s just what we are offering! Besides the actual bicycle path, we primarily provide useable free space with a surface of existing stones that allow leaching. With one small and one large stand, benches, objects to play music on, adjacent unsealed areas where residents can plant vegetation, open WiFi for all, etc. In a nutshell, we offer an inspiring infrastructure. In addition, there is an exhibition on the project with a flexible arrangement and a bicycle repair station. Not least, we hope that the test site will help us gain findings on the pressing questions of the present. For example, we have created green areas with different layouts where we will be testing what leaching or evapotranspiration beds can do for the microclimate, whether plants can clean the rainwater that hits the viaduct and how we can improve the air. Last but not least, we want to know whether a cyclist’s stress levels can be reduced by having information boards telling them whether they will get to the next crossing while the lights are still on green.

Over the course of a multi-level participation process, you gathered ideas and suggestions from residents. Which of these will be incorporated into the testing phase?

As a rule, we scrutinised every idea for the bicycle path published in our book. During an online brainstorming session as well as a multi-day workshop, whose participants were selected at random, we asked questions on the content and design of the test site, without any fixed expectations regarding the outcome. This led to the approach of spatial clusters that ultimately dominated the design: an interactive island and a bicycle island, connected by a central reservation that is designed in part as a sponsored flowerbed. We will implement and test concrete ideas such as an acoustic wall, information boards, seats, an audio playground and a letter box for feedback. During the conceptional phase, residents suggested allowing space for their own ideas as well as a graphic illustrating the project. We considered both during the planning phase and will test their functionality for resonance and acceptance from 25 April on.

What are the next steps for the bicycle path? Will more sections be added?

With the construction of the test site we have now reached a huge milestone. And at this point, one thing is already manifest: when it comes to redesigning space, we need to think big. Both spatially and in terms of the diversity of its use, as was revealed by comments during the participation process, a potential and risk analysis we commissioned and the results of a study on traffic commissioned by the senate department. The latter even considers taking away two road traffic lanes and creating a redesign concept that combines them with the space beneath the viaduct.

Will the project be evaluated? And if so, what results are you hoping for?

The evaluation of the test site is the crux of the funding project. If we want to do it justice, we have to be open to assessing what works well and what doesn’t. We will gather results via our own observations and a user survey conducted by a third-party service provider, which will be conducted on site as well as online in order to reach different target groups. The core question will be how different groups use, perceive and assess our test site. After all the brainstorming workshops we did ahead of the project we are hoping for a factual, empiric foundation that evaluates the results and will allow us to draw up suggestions for the project’s further development. We will summarise the results and make them available to the public, a specialist audience as well as decision-makers in politics and administration.

The Reallabor Radbahn company is working on other neighbourhood projects. Can you tell us what they areand what the team expects from them?

The paper planes association established the Reallabor Radbahn company in order to examine pressing questions around a modern, human-centric utilisation and division of public space on the basis of concrete funding projects. We are pursuing this question over several projects. The Free Street Manifesto was created in cooperation with TU Berlin and the WZB Berlin Social Science Center as a funding project for the Mercator foundation. Our participation project in the Graefe neighbourhood benefits from these findings: we will be redesigning two roads there. The higher goals are to increase traffic calming; an active alternative utilisation of parking spaces by the people who live there; and the unsealing of soil at a large scale, including the associated planting of vegetation.

Reallabor Radbahn is also active in the Smart City Berlin network. What added value does the network offer the team?

As humans, our fate is largely in our own hands. It’s up to us to adapt the city to our wide range of needs. We impose a lot of different demands on a place and its facilities; when it comes to limited resources, “either-or” is not an option. So it’s smarter to answer synergistically, to share and recognise things and react ad hoc. The network provides the ideal foundation for that.

What do you think the city of the future will look like?

The city of the future will be green again and offer space for people with very different daily routines; diversity is the name of the game. A huge library of things is open to all, energy is generated locally and distances are short. The air is inviting enough to do yoga in the streets.

Please complete the following sentence: Berlin is a smart city, because...

... its residents are. We just have to uncover that potential, let it unfold. (vdo)
Reallabor Stadtbahn (German only)




© paper planes e. V.

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