Vienna explores new uses for A23 after Lobau tunnel

The Lobau Tunnel is expected to be built, and Vienna is already considering how the A23 Südost-Tangente could be used once the tunnel is complete, ORF reports. The tunnel is intended to relieve Austria’s busiest motorway, although completion is not expected until the 2040s.

The A23 is about 17 kilometres long, making it Austria’s shortest motorway. At peak levels, it carries up to 220,000 vehicles a day. There have so far been few discussions about what could happen to the road after the tunnel opens.

Vienna transport councillor Ulli Sima of the Social Democratic Party said in 2021 that the motorway should be closed to through traffic once a north-eastern bypass around Vienna is available. The road could then be scaled back, she said. Sima’s office told ORF Vienna that this position remains unchanged. A lane for electric buses could also be considered.

According to calculations by the ARBÖ motoring organisation, the north-eastern bypass, consisting of an expansion of the S1 motorway and the tunnel, could reduce traffic on the A23 by 70,000 cars a day. Several traffic planners and researchers question the likely effect, arguing that a new tunnel could also generate additional traffic.

In its current form, the A23 divides several Vienna districts. Architecture and urban culture journalist Wojciech Czaja said on the ORF podcast Stadtwandel that its separating function could be reduced through cultural buildings and sports infrastructure.

Landscape architect Thomas Kerekes has rejected a complete demolition as impractical and instead proposed uses focused on active mobility. These could include an additional urban walking route, a running track or cycling routes.

Traffic planner Barbara Laa of TU Vienna said a connection for public transport should remain. Buses could be introduced immediately, while converting the route for rail transport would be more difficult and would require a structural assessment. Bus or carpool lanes could also be created in the road’s current form.

Czaja supports retaining the elevated motorway structure and adapting it for new uses. He pointed to the Viaduc des Arts in Paris, the High Line in New York and Seoullo Garden in Seoul as examples of infrastructure converted into public spaces for pedestrians, cyclists and electric scooter users.

In Seoul, about three kilometres of motorway were closed and replaced with a park containing around 30,000 plants, Czaja said. He also called for extensive planting on the A23, describing it as a large, exposed asphalt and concrete surface without shade. Green areas could make it more attractive for visitors and help reduce heat in nearby neighbourhoods.

Kerekes said local residents should help shape the redesign, while warning that the A23 covers an enormous area of at least 500 hectares. Temporary uses could be introduced while a permanent solution is developed.