A1: Six Lanes for a Safer, More Efficient Future
On behalf of the Federal Roads Office FEDRO, the ARGE LUWA joint venture is widening the A1 motorway between Luterbach (SO) and Wangen a.A. (BE) to six lanes. The consortium, comprising Marti AG Solothurn, Marti AG Bern, Frutiger AG and Kibag AG, is delivering one of the most significant road infrastructure projects in Switzerland: a new 220-metre bridge over the Aar, a generous wildlife crossing, the restoration of the Russbach stream and a comprehensive noise mitigation programme. Completion is scheduled for the end of 2027.
The New Aar Bridge: The Heart of the Project
The Western construction lot sits at the core of the overall scheme. Alongside the existing double-span structure, a new bridge is taking shape over the Aare, measuring 220 metres in length, 15 metres in width and weighing approximately 25,000 tonnes. Its reinforced concrete design allows for long, uninterrupted spans, ultimately accommodating three traffic lanes and an emergency stopping lane in the direction of Berne. Beyond its impressive scale, the bridge stands as a clear statement of long-term investment in Switzerland's national road network.
Engineering and Ecology, Working Together
Directly beneath the A1, a new wildlife crossing is being constructed: 42 metres long, 32 metres wide and 5.5 metres high. The structure is built using in-situ cast concrete, and a single pour of around 700 cubic metres represented a significant feat of logistics and coordination, carried out seamlessly thanks to careful planning and a well-rehearsed team.
The crossing is designed to give wildlife a safe route through the motorway corridor and to ensure lasting ecological connectivity between the surrounding habitats. It is complemented by the restoration of the Russbach stream, a further contribution to the environmental enhancement of the project area.
Noise Barriers, Interchanges and Infrastructure
Existing noise barriers are being repositioned, extended and in places raised to a height of three metres. At the same time, the Oensingen and Egerkingen interchanges are being redesigned to improve traffic flow and reduce pressure on local town centres.
The works also include extensive drainage, utility and trackbed construction, as well as two road runoff treatment facilities, unassuming but essential components of any modern motorway infrastructure.
“At the LUWA joint venture, construction complexity and diverse requirements make for a highly demanding project. It is this combination of technical precision, close collaboration and forward planning that makes the work especially rewarding.”
Facts & Figures
- Client: Federal Roads Office FEDRO
- ARGE LUWA: Marti AG Solothurn, Marti AG Bern, Frutiger AG, Kibag AG
- Section: A1 Luterbach (SO) to Wangen a.A. (BE)
- New Aar Bridge: 220 m long, 15 m wide, 25,000 tonnes
- Wildlife crossing: 42 m long, 32 m wide, 5.5 m high
- Noise barriers: up to 3 m in height
- 2 road runoff treatment facilities