Turnaround for the Lobau Tunnel: Is the Mega Construction Project Returning?

The long history of the unbuilt Lobau Tunnel as part of the S1 section Schwechat-Süßenbrunn begins in 2001. Initially, there was also talk of a sixth Danube bridge, but with the completion of the Strategic Environmental Assessment "SUPer NOW" in 2003, the tunnel became the controversial centerpiece of the project. In 2021, it seemed to be history, but in 2025, with the traffic light coalition, the road project, which was initially halted by former Minister Leonore Gewessler (Greens), is once again facing a comeback.

Lobau Tunnel: Stopped Project Facing a Comeback?

At the end of February, Peter Hanke, SPÖ Federal Minister for Transport, Innovation and Technology, expressed his support for the tunnel in an interview. He stated it is "very important for the federal capital and the eastern region. Therefore, there will certainly be the necessary implementation here." Already in the previously published government program of the coalition of ÖVP, SPÖ, and NEOS, the construction of already approved highways and expressways was announced, but the tunnel was not mentioned by name. Only the S1 link was mentioned.

Chronology: The Long Struggle for the Vienna Northeast Bypass

The following provides information on the key points:

Lobau Nature Reserve vs. Regional Ring

Lobau Nature Reserve - The Lobau is part of the Danube-Auen National Park, an area of about 9,300 hectares between Vienna and Bratislava, whose establishment was celebrated in October 1996 as part of a 15a agreement. According to information from the City of Vienna, the area, divided into Upper and Lower Lobau, covers about 2,300 hectares and accounts for 24 percent of the total area of the Danube-Auen National Park. The threat to this area, as well as the feared additional traffic burden in the context of climate goals, are among the main arguments of the project's opponents.

Vienna Northeast Bypass - The Lobau Tunnel is part of the Vienna Outer Ring Expressway S1, a section of the Vienna Northeast Bypass and thus the "Regional Ring" around the federal capital. It is designed as a four-lane route with a length of 19 kilometers, intended to connect Schwechat and Süßenbrunn. The 8.2-kilometer-long and approximately 60-meter-deep tunnel is planned to run under the Danube and the Lobau Nature Reserve. The southeastern part of the S1 (from the Vösendorf junction to Schwechat) has been in operation since 2006. The "Regional Ring," the traffic relief for Vienna it is hoped to provide, and the connection to the northeast are the main arguments of the tunnel's proponents.

Variable Implementation Announcements from 2014 to 2025

Construction Time and Costs: The latest estimate of the total costs, according to the "Strategic Assessment" (SP-V) from February 2025, amounts to 2.4 billion euros. In 2018, the Autobahnen- und Schnellstraßen-Finanzierungs-Aktiengesellschaft (Asfinag) estimated 1.9 billion euros, seven years earlier it was 1.8 billion euros.

The details regarding construction time and the completion of the work developed very variably: According to initial plans, the project should have been completed by 2014, but in 2006, City Councillor for the Environment Ulli Sima (SPÖ) postponed it to 2015. In 2007, the then Minister of Infrastructure Werner Faymann (SPÖ) announced the "new traffic planning" with a traffic release in 2018. Transport Minister Doris Bures (SPÖ) followed around 2011 with the announcement of a construction start in 2018 and a release in 2025.

City Street - S1 Link: The Northeast Bypass project also includes two equally controversial connecting roads, namely the S1 Link as a 4.6-kilometer connection between the Raasdorf junction and the Seestadt district. Like the bypass, the project falls under federal jurisdiction. City Street: From Seestadt, another 3.2-kilometer route leads across Vienna-Donaustadt to connect the Southeast Tangent (A23, Hirschstetten junction) with the S1 Link.

Long Wait for Environmental Compatibility

Environmental Impact Assessment - The Environmental Impact Assessment (EIA) for the Lobau Tunnel took a total of about nine years. Project sponsor Asfinag submitted the project in 2009 and assumed that the EIA and further nature conservation and water law procedures could be completed in 2010 and construction could start in 2011. However, it took until 2015 for the first positive decision for the S1 section from Schwechat to Süßenbrunn - including the Lobau Tunnel. Environmental organizations and citizens' initiatives responded with a complaint, and in spring 2018, the Federal Administrative Court gave the green light for construction under conditions.

Protests - In response to planned test drillings by Asfinag in the Lobau, environmentalists held a vigil against the Vienna Northeast Bypass under the national park in November 2006. With their camp on the edge of the floodplain, the activists aimed to prevent Asfinag's test drillings. The protests intensified over the years and finally escalated on February 1, 2022, with the clearing of the protest camp at Seestadt Aspern. The action, carried out by a large police force, resulted in numerous arrests and the use of pepper spray.

Asfinag Construction Program Loses the Tunnel

Asfinag Construction Program - Asfinag is responsible for the planning, construction, operation, and tolling of the Austrian motorway and expressway network. In July 2021, the Ministry of Climate Protection announced the evaluation of the Asfinag construction program by autumn, and all projects were put on hold. In December, Minister Gewessler then announced the construction stop. Only the S1 Link could be built. Sharp criticism came, among others, from Vienna's Mayor Michael Ludwig (SPÖ). In September 2022, the road construction program without the tunnel was signed by Finance Minister Magnus Brunner (ÖVP).

Federal Roads Act - However, the Vienna Outer Ring Expressway (S1) remained part of the Federal Roads Act (BStG 1971). The "Strategic Traffic Assessment" (SP-V) for the Lobau Tunnel, initiated by the then Minister of Climate Protection Gewessler in 2022 and published in 2025, recommends its removal from this. From the perspective of the environmental organization Virus, based on a legal opinion from the University of Innsbruck from 2024, the S1 entry in the BStG should be disregarded due to EU illegality. The same NGO also reported at the end of 2024 on a water law procedure that had not yet been completed.

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(APA/Red)

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