The Hamburger Deckel is an infrastructure improvement project on one of Germany’s busiest and longest motorways, the A7. The project is in direct response to the increasing traffic congestion and growing patronage along the motorway, which runs for 964km and linking Denmark in the north and Austria in the south.
For decades this vital road link has been a major headache for the residents of Hamburg, Germany’s second largest city and Europe’s second largest port. Since its construction several decades ago, the 6 lane freeway has created a major physical barrier disconnecting the communities on either side. The residents of the Schnelsen, Stellingen and Bahrenfeld districts of Hamburg have endlessly expressed their concerns over the large levels of unwanted noise and air pollution generated by the heavy truck and car traffic along these sections of the freeway. Community pressure groups have been campaigning for over three decades, demanding that federal and local governments provide a solution to the noise and air pollution problems generated by the A7. These demands remained unanswered for a long time due to a lack of government funding.
However, the A7 has developed into one of the worst bottlenecks in the country and has finally managed to attract the German government’s attention. The current flow of 152,000 vehicles per day is predicted to rise to as much as 165,000 by 2025 between the Bahrenfeld and Schnelsen sections of the motorway. The current and predicted vehicle flows will exceed the designed threshold by at least 26%, which has lead to the decision by the City of Hamburg and Federal Government to install an additional two lanes and a number of new slip roads to relieve this bottleneck.
The City of Hamburg has decided to tackle this project of cross generational significance not only as an infrastructure and engineering problems, but also one that will eliminate the “wall of noise” and physical barrier stretching across the three districts of Hamburg.
This primary design principle gave rise to the “Hamburger Deckel cut and cover” solution consisting of three new road tunnels through the districts of Schnelsen, Stellingen and Bahrenfeld, with a total combined length of 3.5km. The concrete and parkland canopy for the tunnels span on average 34m and have an average structural depth of 2 to 3 meters. Aimed at reconnecting the disconnected districts and stitching together the urban fabric, each tunnel deck is to support new extensive parklands, allotments of community gardens and parcels for new residential developments.
The project is expected to cost around AUD$1 billion and take almost 10 years to complete, with the largest 2km section at Bahrenfeld to be completed last by approximately 2025.
The first section of the project at Stellingen began construction in 2012. The standard cross section of this part of the tunnel is 22.5m wide and 893m long.
The tunnel cover supports a surface of park, new residential development parcels and allotment gardens. A planning and design competition was conducted in 2010 with the winning design chosen to be implemented once the tunnel deck is completed.
The main design principle followed in this section of the Hamburger Deckel project was primarily to reconnect the communities on either side of the A7. This will be achieved by the establishment of a green corridor through the city. The tunnel deck will provide a new vast open space for leisure and recreation activities. This “cut and cover” solution aims to directly solve the noise and air pollution problems raised by the community by providing an effective physical noise barrier. It will also offset pollution generated by traffic exhaust through the establishment of new parklands and meadows. The landscape designers also saw the tunnel deck as an opportunity to create a new tree lined town centre square where the community can hold festivals and markets, further facilitating the initial design idea of bridging the previously disconnected communities.
Following the same design principles, the 560m long tunnel deck at Schnelsen will create a spacious new park bordered by trees and flanked by small gardens. The idea of reconnecting communities is again addressed through the establishment of a new town centre and market space.
The residents of the district can also make use of the series of community garden allotments located to the north of the deck with a pedestrian and cycle connection running along the length of the freeway. Once again, cafés and public open spaces will be established where community activities such as markets and festivals can be held, turning the area into a new heart of the Schnelsen district.
Extending along 2030 metres, reaching from the S-Bahn urban railway line all the way to Volkspark, the Bahrenfeld section of the tunnel will be the project’s longest covered motorway segment. The construction period will last approximately four years and the cost will be shared between Hamburg and the federal government.
A new urban neighbourhood comprising approximately 1700 homes will be built in between the horse racing track and Schnackenburgallee with most of the existing allotment gardens transferred on top of the tunnel cover. Once again, this new urban landscape is primarily dedicated to the community’s leisure and recreation activities. The new tunnel deck will also provide a link into the existing parkland around the northern section of the tunnel and establish a green corridor through the city.
The success of the “cut and cover” solution is that it not only provides an effective noise barrier to protect the community and mitigate the air pollution problems created by the A7, it also provides new opportunities for residential development which can contribute to the financing of the project.
The Hamburger Deckel project has been community driven from the outset. During the planning process the community was engaged at a number of stages, with regular workshops and public events held within the communities. These workshops were used as an opportunity to create a design brief for the landscape design competitions, ensuring the needs of the residents were incorporated into the design outcome. Throughout the planning process, consultants and planners were in close contact with the districts’ residents through public consultations and regular publications of design proposal documentation. This created a transparent planning process with regular community feedback.
In terms of project financing, an infrastructure improvement scheme on a scale such as that proposed for the Hamburger Deckel was inevitably to be shared by the federal government. The only precondition for obtaining federal funding was that the German Federal Transport Infrastructure Plan classified the project as being urgent. This was established to be the case for the A7, with consideration given to the large amounts of community pressure to solve the traffic congestion and noise issues, as well as the issue of increasing vehicle patronage.
First estimates put the City of Hamburg’s share at AUD$215 million in investment costs, plus AUD $24 million for planning. It was decided that the land owned by the City of Hamburg at the edge of the noise-reduced motorway was to be offered to private property developers. The sale of this land will contribute to the costs of the project and offset the financial burden on Hamburg. The total project cost is split between the City of Hamburg (17%) and the federal government (83%).
The only negative response to the Hamburger Deckel so far has been the concerns of existing owners of garden allotments which will be forced to relocate during construction and then again to the tunnel roof once completed. Critics have also showed concern over possible loss of business productivity due to the long delays caused by construction activities. Similar fears are shared amongst road users which feel that the lengthy construction will cause major disruptions to an already strained vital roadway in Hamburg and Germany.
This type of project procurement and community involvement is very interesting and an important case study for the Streets Without Cars agenda, as local community support and feedback will be essential in identifying what opportunities exist when we reimagine our local streets as spaces for pedestrians instead of cars.
- City of Hamburg, Freie und Hansestadt Hamburg; A7 Information Brochure.
- Ibid.; p. 18.
- Ibid.; p. 12.
- Ibid.; pp. 4-5.
- Mark Boyer; Hamburg is building a giant green roof cover over sections of the A7 Motorway; Inhabitat; November 2011.
- City of Hamburg, Freie und Hansestadt Hamburg; A7 Information Brochure; pp. 6-7.
- Ibid.; pp. 6-7.
- Ibid.; pp. 7-8.
- Ibid.; pp. 18-19.
- Ibid.; pp. 16-17.
- Simon Tomlinson; The underground motorway: Germans plan to cover one of Europe’s longest autobahns with a giant park; Daily Mail; December 2011.
- A7 Motorway, image sourced from The City Fix.
- Issues with the A7, author’s own image.
- Hamburger Deckel, image sourced from The City Fix.
- Project overview, author’s own image.
- Project timeline, author’s own image. Maps sourced from the City of Hamburg: here and here.
- Project proposal, author’s own image. Renders sourced from the City of Hamburg: here, here and here; and Inhabitat.
- Stellingen design principles, author’s own image. Renders sourced from Inhabitat.
- Project images, sourced from the City of Hamburg: here, here, here and here.
- Schnelsen design principles, author’s own image. Renders sourced from the City of Hamburg.
- Bahrenfeld design principles, author’s own image. Renders sourced from the City Hamburg: here and here.
- Planning process, author’s own image.
- Project cost analysis, author’s own image.
- Community response, author’s own image.