All of our 164 tunnels are cleaned, and the dust and soot is removed from the walls. Sometimes up to 70 people clean the tunnel at the same time. From the curb reflectors and the lighting to the emergency phone niches and the video cameras - everything is cleaned and broken parts are replaced.
Drawing up the tunnel wash schedule is also a big challenge. While these steps are necessary for road safety, there must be as little obstruction as possible to the traffic. That's why this work is largely carried out at night.