A9 Visp South Bypass Road, Eyholz and Visp Tunnels and Staldbach-Bridges

The Visp South Bypass is part of the A9 road completing the national road network in the communities of Visp and Eyholz. It consists of both the Eyholz and Visp tunnels as well as Staldbachbridges, which pass over the Vispa Valley and connect the two tunnels.

Eyholz Tunnel consists of two tubes each with two lanes as well as underground junctions connecting the entrance and exit tunnels with the cantonal road in the Vispa Valley.  Visp Tunnel is composed of a new dual lane tube as well as the underground half junction of the national road with the Vispertäler. The existing Vispertal Tunnel will be incorporated as part of the south tube of the A9. The half junction consists of 3 underground junctions, an overpass tunnel and the existing Vispertal Tunnel as the exit to Zermatt. Cross connections to the adjacent tube serving as escape routes for pedestrians and vehicles are integrated into the tunnel.

Both tunnel tubes have operation and ventilation  stations at the tunnel portals as well as underground technical rooms to house operation and safety system components. The new tunnel tubes have intermediate ceilings above which there is an exhaust air duct.

In the existing Vispertal Tunnel the intermediate ceiling will be rebuilt and adapted to the new ventilation system with jet fans in the tunnel and air will be extracted via controllable air flaps in the intermediate ceiling. An accessible service duct will be integrated into the tubes.

The tunnels cross the Rhone-Simplon fault line, which is characterised by strong tectonic stress and squeezing rock conditions. The tunnels were blasted and excavated in loose rock zones with machine-aided propulsion. In the loose rock sections the tunnel was advanced under the protection of a pipe umbrella system.

Main Data

Eyholz Tunnel

  • South/North tubes 4,255 m /4,231 m
  • Entrance tunnel 368 m
  • Exit tunnel 256 m
  • Junctions 443 m /280 m

Visp Tunnel

  • North tube 2,645 m
  • South tube new build 922 m /1,694 m reconstructed
  • Exit to Zermatt 1,224 m
  • Overpass tunnel 1,641 m
  • including junctions: 435 m /241 m /131 m


Department of Transport, Construction and Environment of Valais Canton, Office of National Road Construction


IUB Engineering Ltd in consortium

Construction period

2005-2015 Eyholz Tunnel, 2005-2020 Visp Tunnel, 2004-2006 Staldbachbridges

Construction costs

Eyholz Tunnel: CHF 722 Mio. ; Visp Tunnel: CHF 425 Mio. ; Staldbachbridges: CHF 15 Mio.

Scope of services

  • Feasibility study
  • General design/preliminary project
  • Detailed design/construction project
  • Input for the detailed project for construction
  • Implementation project
  • Construction supervision
  • Commissioning and completion