The tunnel will create an extension of the existing Ligerz Tunnel at the eastern exit to relieve congestion in the village of Twann. It will divert traffic away from the village, allowing for the redevelopment of the village centre, improving conditions for cyclists and pedestrians.
The Twann Tunnel project has a total length of 1.924km, including a two-way two-track monotube of about 1.8km, a technical duct under the road on part of the linear, two symmetrical stop enlargements and a unilateral stop widening near the end of the tube at the east portal.
The contract also includes material management services, including analysis, valorisation, treatment design, and geotechnical services.
