Sonnenberg Tunnel

There are tentative plans to construct a bypass to replace the section of the motorway that leads through Lucerne, which includes the Sonnenberg and Reussport tunnels.

A seven-story cavern between the tunnels contained shelter infrastructure including a command post, an emergency hospital, a radio studio, a telephone centre, prison cells and ventilation machines.

The only large-scale test, a five-day exercise in 1987 to practice converting the road tunnels into usable shelters, revealed many problems: among other things, it took 24 hours to fully close all four blast doors, and it proved impossible to set up the 20,000 beds within reasonable time.

After the end of the Cold War, the high maintenance costs seemed unjustified for an installation that was clearly geared towards use during wartime and couldn't be readied within hours for short-term use after disasters.

In 2006, after a long political debate, it was decided to abandon the road tunnel's secondary civil defense function and instead convert the central seven story cavern into a shelter with a more modest capacity of 2,000.