The overall idea of the awarded submission is the transformation of the main corridor B14 from a monofunctional piece of infrastructure into a vibrant environment. The concept envisions a maximum amount of open space that meets the needs and desires of the city’s citizens. Based on Stuttgart´s specific context, the project team focused rather on regaining public spaces in the downtown than computing shifts in the transportation system or developing technology-based visions.
Going up! – Recapture of a city highway The highway B14 cuts through the urban fabric of the state capital Stuttgart with up to ten traffic lanes. The main task of the international urban design competition was the redesign of about five kilometres of this disrupting traffic corridor and to continue the already started paradigm shift from the car-centric to the human-centric city. The participants were able to base their concepts on the assumption that future traffic volume will be reduced by 50 percent.
New places and environments The traffic that currently runs through underground tunnels on many occasions in the project area, is being pulled up to the ground level. Additionally, the street width is being reduced to two, or to a maximum of four lanes, in order to create more space for cyclists and pedestrians. New crossings at neuralgic locations further weave together the urban fabric. That way the former highway becomes a regular city street with an additional benefit: the regained areas offer various opportunities for appropriation of urban spaces, whether for living, office, culture, sports, or other leisure activities.
Sequences The street is read more as a succession of different gathering spaces and squares than a linear axis. Depending on location, significance, or history, some areas are being redefined and loaded with functions and activities. Existing links are being incorporated. Based on these “city rooms in the public realm”, the street is being reconnected with its surroundings while new and existing pedestrian paths are being highlighted and strengthened.
Transformation instead of negation Especially in Stuttgart, the transportation infrastructure of the car-centric city stands for a part of urban history. To demolish it completely would be a negation of this important part of the citys more recent history. Despite the consequent redesign of the streetscape, on- and offramps as well as tunnels are mostly being conserved. In the area of the subway stop Charlottenplatz and around Paulinenbrücke, those infrastructure pieces are being transformed into multi-purpose environments and urban spaces. In other areas, the vacant streetscapes are being redeveloped into hubs for mobility and logistics. This results in a fine-meshed network of future distribution and transfer facilities all along the redesigned B14 corridor.
Extension of the “Kulturmeile” In the downtown, historic city fabric is being adopted and interpreted in a new way. Street walls and squares are being restored. The new city blocks around Esslinger Straße incorporate important culture uses like Haus der Kulturen, new Lindenmuseum, and Filmhaus. The “Kulturmeile” gets extended to Leonhardskirche and Gustav-Siegle-Haus. Due to the strong connection to the area around Marktplatz the now much larger neighbourhood can develop into a buzzing centre.
Gaining ground Even after the redesign of the street and the open space, the city is left with oversized scars without scale in some locations. To regain an appropriate streetscape, we propose some new building fabric between Charlottenplatz and Österreichischer Platz. Through this adequate infill development, much needed living space gets created. It could be considered to partly refinance the redesign of B14 through proceeds from real estate sales.
Urban ecology The quality of urban spaces is linked closely to its ecological and climate quality. Available areas will be constructed mostly without impervious surfaces and trees enhancing the city climate will be planted. The trees, in contrast to most other instances, are not compromised by a small bed but are planted in a spacious green space that are planted with mixed species to support the city’s biodiversity. A smart system of rainwater collection channels downpour through bioswales into the soil where it becomes available for trees and plants. All those efforts support storm water protection, avoid heat islands, and enhance the ecological diversity.
Vast green corridors that link existing open spaces weave together the city´s fabric across B14 in an ecological and climatic manner. Instead of planting trees in raised beds lining the corridor, the classical tree alley reappears in the urban environment. Different tree species create changing impressions and sensations throughout the year.