The Future is Green: Radbahn’s vision of revamping cityscapes for sustainable living

Compared with other major capital cities around the world – London, Paris, or New York – Berlin feels wonderfully capacious. Wide streets, exquisite parks in every central neighbourhood and yet still, plenty of dormant space. As its population continues to blossom, however, the German capital will need to redefine its districts to better serve the needs of citizens. Enter Radbahn, an ambitious project that would transform the abandoned area beneath the elevated U1 subway line into a lively promenade for residents.


Charmaine Li


Robert Rieger

Urban landscapes are growing exponentially. In 1950, one-third of the world’s population lived in cities, but by 2016 this number had grown to more than half, according to data from the UN. By 2030, cities are slated to house two-thirds of the world’s population. Yet rapid urbanisation comes with a slew of challenges, as well as opportunities. Thankfully, forward-thinking city planners around the globe are coming up with new initiatives to accommodate the expansion and create better ways of living and working for the future.

For the interdisciplinary team of architects, urban planners and cultural managers behind the Radbahn project, Berlin’s ever-changing landscape is an opportunity to rethink the cycling infrastructure and repurpose the 9 km of underutilised space beneath the overground sections of the U1 – from Zoologischer Garten to Oberbaumbrücke – for public use. ‘Initially, the idea was to use the space as a bicycle lane, but the concept has since evolved into something bigger,’ says Perttu Ratilainen, Radbahn’s business mind and one of the eight founding members of paper planes e.V., the non-profit association behind the project. ‘Once we understood the quality of the space, the Radbahn concept started to include elements like e-mobility hubs at key public transport intersections as well as arts and culture projects in collaboration with the local community. It’s much more than just a bicycle lane now.’

The idea for Radbahn came about in 2014 and stems from Finnish entrepreneur Martti Mela, who is a friend of an architect of the Radbahn team, Matthias Heskamp. Martti and Matthias were questioning why it wasn’t possible to cycle on the path under the U1 and this sparked a series of events that led to developing the Radbahn concept, which was unveiled to the public the following year after months of honing. For the initial stages, the Radbahn team did not work under any official organisation but in 2016 they founded paper planes e.V. and registered it as a non-profit.

‘It’s about inspiring people to live a different lifestyle.’

Berlin’s population grew from 3.4 million in 2014 to 3.5 million in 2016 and the city’s Senate predicts it will reach 3.75 million by 2030. This trend has made mobility an issue, with extra pressure on public transport and an increase in traffic congestion and air pollution. Although Berlin is hoping to implement strategies that make so-called eco-mobility (on foot, by bicycle, or by public transport) more attractive by 2030, it has a long way to go. ‘Many roads here still don’t have bicycle lanes and the ones that exist are often in awful condition,’ says Perttu. ‘And then there are some car drivers – not all of them – that have an aggressive attitude towards cyclists.’

Selim Guelbas, an intern at Radbahn and a student in the Urban Future programme at the  University of Applied Sciences Potsdam, agrees. ‘As cities are getting older, the people living in them are also getting older,’ he explains. ‘We need to think about that when planning for the future. At the moment, Berlin is quite a dangerous city for cyclists – I rarely see older people or kids on the bicycle lanes. It’s important that they become safer for everyone.’

Perttu isn’t a fan of increasing the number of vehicles in the city and is even less enthused by car culture and ownership. However, he stresses that Radbahn was never about pitting one mode of transport against the other but creating a space for both. Most of all, it’s about making cycling so attractive that more and more people will want to ride their bikes. ‘Of course, the environmental aspect is important but at its core, Radbahn is about inspiring people to live a different lifestyle.’

Copenhagen and Amsterdam are considered model cities for cycling infrastructure and are certainly much more advanced than Berlin. Research shows that cycling is not only good for the environment and livability of cities but it also comes with economic, health, and societal benefits. By incorporating protected lanes, these cities have demarcated a safe space for cyclists of all stripes and so have proved successful. In Copenhagen, 41% of commuter trips are made by bike, according to 2017 data, a number that rivals can only aspire to.

‘We want to create a feeling for everyone that it’s a beautiful, shared public space where people can feel safe biking.’

Seville is another city reaping the benefits of investing in a segregated bicycle network. In 2006, Spain’s fourth largest city barely had any such infrastructure and, unsurprisingly, only 0.5% of all journeys were made by bike. After building 80 km of segregated bicycle lanes within 18 months (impressive in itself), the average number of all trips made by bike jumped to 6% in 2014. Although not yet at the levels of the Dutch or Danish, the growth has still been incredible.

If the Radbahn project comes to life, it would go even further than the cycling infrastructure of Amsterdam, Copenhagen and Seville, as its goal is to not only transform the underutilised space beneath the U1 into a cycling path but also to create a vibrant promenade for the community to foster connections. ‘With gentrification happening so fast, there are currently so many divisions within the city – between the young and old, rich and poor, foreigners and locals,’ explains Perttu. ‘With Radbahn, we want to create a feeling for everyone that it’s a beautiful, shared public space where people can feel safe biking and also interact with one another.’ At the moment, the paper planes team is rallying support for Radbahn from key stakeholders in the city and hope to have a section of the project built by 2021.

The concept has similarities with Paris’s Promenade Plantée and the High Line in New York  – two abandoned, elevated railway viaducts that were revamped into lush public parks lined with greenery. The main difference is that Radbahn is on the ground level and incorporates a bicycle lane, which means taking into account the existing transportation infrastructure and requires even more detailed planning. ‘If people are interested in changing their own urban environment, it’s something that can certainly be done but it requires a lot of work and it doesn’t happen overnight,’ says Perttu.

When asked about the current status of the project, Perttu says the team is trying to convince Berlin’s authorities to conduct a technical feasibility study for some of the sections of Radbahn so they can plan more detailed design specifications. If the study goes through as planned, Perttu and his colleagues will host a showcase event revealing what one section could look like and start engaging with residents to gather feedback on how to approach the rest of the development. It would make the project more tangible for the public and hopefully, reel in more support to realise the vision.

Ideally, Perttu says, all of these efforts would lead to one section of the Radbahn being built by 2021, in time for Germany’s federal elections. That timeline may sound distant but as Selim notes, it took the city of New York nearly six years to take ownership of the High Line. ‘We’re actually a little bit ahead of them, since we’ve already received some support from the city,’ smiles Perttu. In addition, the Radbahn team was presented with an Ecodesign Award in 2015, from the Federal Environment Ministry in Berlin.

‘I’m so impressed by the many people who have supported the Radbahn project through their work and contributions.’

Turning Radbahn into a reality is no easy feat, especially in Berlin, where projects like the Brandenburg airport – which was supposed to open in 2012 – continue to be plagued with technical issues and delays. For the Radbahn team, some of the biggest challenges they face come from a lack of resources – timewise and financial. ‘It’s difficult to stay motivated when there’s so much uncertainty involved,’ says Perttu, ‘Especially when you don’t know what’s going to happen in the next couple of months or whether we’ll have enough money to continue.’ Although the project has received bits and pieces of financial support from the government, a crowdfunding campaign, and some corporations, most of the founding team members have full-time jobs elsewhere and a large chunk of the work contributed thus far has been from volunteers. The overwhelming support from people of all backgrounds in the city is what has kept the team going.

In the spring of 2017, the team developed a 140-page book with the help of experts and volunteers that acts as a preliminary study on Radbahn. The publication delves into the project’s feasibility as well as the many ways that Berlin would benefit from it; environmentally, economically, and culturally. ’I’m so impressed by the many people who have supported the Radbahn project through their work and contributions, from producing promotional films and content to conducting research and giving donations,’ says Perttu. ‘This wouldn’t have been possible without the support from all of these people.’

Because of the unwavering support that Radbahn has received, the team remains optimistic and continues to encourage people to get involved, whether through financial support or otherwise. Pettru says they’re also open to collaborating with corporations and other groups who want to improve Berlin’s cycling infrastructure and future cityscape. For the project to move forward, staff will need to be paid for their hard work.

绿色的未来: 单车公路希望改造城市风貌以实现可持续生活



Charmaine Li


Robert Rieger


单车公路企划背后有建筑师、都市规划者和文化管理者等跨学科的团队,柏林不断变化的景观是一个重新思考单车结构的契机,将地铁线U1 从Zoologischer Garten到Oberbaumbrücke上方未使用的空间重新规画让大众使用。 单车公路的商业脑与“纸飞机e.V.”(该企划背后的非营利协会)的八个创始成员之一的骆培图Perttu Ratilainen说:“起先,这个点子是给单车族的使用空间,但这个概念也延伸成更广的东西。"“当我们了解空间的质量后,单车公路企划开始涵盖如主公共交通路口的电子移动中心,与当地小区合作艺术与文化项目相关的元素。”现在它不只是一条自行车道了。

单车公路的想法源自于2014年芬兰企业家梅马丁Martti Mela,他是单车公路团队建筑师何马蒂Matthias Heskamp的朋友。马丁和马蒂质疑为何不能在地铁线U1的路径上骑自行车,这引起一系列演变成单车公路的概念,此概念经过多月琢磨后,来年即与大众揭晓。初创阶段,单车公路团队并无在任何官方组织下工作,但在2016年他们发起纸飞机e.V. 并登记为非营利组织。


柏林的人口量从2014年的340万增长到2016年的350万,该市的参议院估计至2030年将达成375万。这个趋势使交通成为问题,大众运输流量有更多压力、交通拥挤与空气污染与日俱增。虽然柏林希望在2030年实施所谓的生态交通策略 (采步行、使用自行车或大众运输),但仍有很长的路。培图说:“这里仍有许多街道没自行车道,现有的自行车道路况也实在糟糕。”“并非全部但有些汽车驾驶者,他们对自行车者抱持恶劣的态度。”

单车公路的实习生葵赛琳Selim Guelbas在波兹坦应用科学大学主修都市未来课程,同意着并解释说:“当都市越来越老时,居住在里面的人也是,计划未来时我们必须考虑这点。此时,柏林对自行车族算是相当危险的都市。我很少看见老人或小孩在自行车道上,重要的是车道对每个人都要安全。”





假如单车公路企划可付诸实现,自行车结构系统将会比阿姆斯特丹、哥本哈根和赛维利亚更进步,其目标不只是将地铁线U1未使用空间转变成自行车道,更想为小区创造出一条生气勃勃、促进联系的步道。 培图解释:“士绅化发展迅速,无论是年轻人或老人,有钱人或穷人,外国人或本地人,城市内部现仍存在许多分歧。” “我们藉由单车公路计划,想为大家创造一个美好的公共空间,让人们骑自行车感到安全并能彼此互动。” 此时,纸飞机团队正和城市内部相关者为单车公路企划争取支持,并希望在2021年建盖企划中的一部分。

这个概念与巴黎的Plantée 车道、纽约的高速车道均有相似之处,将两座废弃的铁路高架桥改建成绿意盎然的公园。单车公路最与众不同之处是在地面上结合自行车线,那意味着整合现有交通系统,此举需更多详细计划。培图说: “如果人们对改变都市环境感兴趣,现在绝对是可行的,但这需要许多工作,并非一日就能完成。”


培图说理想上,所有努力可更向前并在2021年前盖好单车公路的一部分,正好赶上德国联邦选举,这个时间听起来或许遥远。但赛琳补充,纽约得到高速道路的拥有权也花了六年的时间。 培图笑说:“我们已获取城市的一些支持,其实我们的进度还比他们快呢。”此外,单车公路团队在2015年获得德国联邦柏林环境部颁发的生态设计奖。


将单车公路计划变成事实并非易事,尤其柏林有布兰登堡机场的企划案,原本早该于2012年启用,但一直遭受技术问题和延误的困扰。对单车公路团队而言,其面临最大的问题在缺少资源、时间和金钱。培图说: "当许多不确定因素存在时,很难保持动力。""尤其你对接下来几个月将发生的事一无所知或是否还有足够的钱去支撑企划案。"虽然这个企画案得到一些来自政府、民间募款、公司的财务支持,多数的创始成员都有自己的正职工作,至今的工作大多来自志愿者的贡献。获取城市中各种背景、排山倒海的支持使得这个企划能持续运作。




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