A9 Bypass Visp South, Eyholz and Visp Tunnels

The Visp Southern Bypass is part of the A9 motorway in the Rhone Valley. It consists of the Eyholz and Visp tunnels as well as the Staldbach bridges over the Vispa River Valley. The Eyholz Tunnel includes the new construction of two tubes as well as underground junctions to connect the entry and exit tunnels with the cantonal road in the Vispa River Valley. The Visp Tunnel consists of two dual lane tubes and an underground semi-junction with the Vispa Valley. The existing Vispertal Tunnel will be integrated into the south tubes. Three underground junctions and an additional tunnel tube were constructed for the semi-junction.

Operating and ventilation control systems are located at the portals of the Eyholz and Visp tunnels and the tunnels have underground technical facilities to house the operating and safety systems. Service ducts have been constructed under the roads. Ventilation for the respective tunnels is provided via intermediate ceilings (ventilation duct) and ventilation control units at the portals, which are connected with the tunnel tubes via a ventilation shaft.  
Visp Tunnel crosses the Rhone-Simplon fault line which consists of squeezing rock as a result of heavy tectonic stress.

The tunnels and galleries were excavated by drilling and blasting and using machine-aided driving in the loose rock zones. In the loose rock sections and in the fault zones ringed inverted vaults were constructed for reinforcement and for the inner shell.

Main Data

Eyholz Tunnel

  • South tubes: 4,255 m
  • North tubes: 4,231 m
  • Entrance tunnel: 368 m
  • Exit tunnel: 256 m
  • South/north junction up to 307 m2:443 / 280 m

Visp Tunnel

  • North tubes: 2,645 m
  • South tube new build/reconstruction: 922 / 1,694 m
  • Junctions 1 / 2 / 3 up to 307 m2: 435 / 241 / 131 m
  • Overpass tunnel: 1,641 m
  • Vispertäler exit: 1,224 m


Department of Transport, Construction and Environment, Wallis Canton, Office for National Roads Construction


IUB Engineering Ltd in consortium

Construction period


Construction costs

CHF 1.2 billion

Scope of services

Planning and construction supervision in the phases: construction project, tendering, execution planning, implementation and commissioning.