Some may have perhaps noticed in the last couple of weeks that tunnels throughout the country are being closed at night.

What people don’t get to see is the big clean up that’s taking place on the inside. These happen twice a year, and for good reason: RTL went to see why and how the operation transpires.

Ponts et Chaussées have the tunnels cleaned twice a year for safety reasons, according to Ralph di Marco.

Tunnels are consequently closed for maintenance shortly after, especially since the water and dust thrown up by the cleaning processes might damage cameras.

On 19 March, the tunnel underneath the Serra roundabout in Kirchberg was up for cleaning.

In total, 25 tunnels and wildlife crossings are being cleaned.

The Swiss company that is here for 2 weeks for the job are off on Sunday before they’re back again in autumn. By then, vents will have clogged up and be in need of another clean.