Norway’s Lærdal Tunnel at 24.5 km is the world’s longest – featuring three lighting designs to prevent driver drowsiness

By Rita

Have you ever driven through the Snow Tunnel from Taipei to Yilan on a holiday? Feeling like you're about to lose it after just half an hour stuck in traffic? The Snow Tunnel is 13 km long in total — but how about trying the longest tunnel in the world? It’s located in Norway and stretches an incredible 24.5 km.

▲ Norway’s Lærdal Tunnel (Photo / Wikimedia Commons, the same below)

According to Entertainment Planet’s summary, the world’s longest tunnel, the Gotthard Base Tunnel in Switzerland, measures 57 km in length — but strictly speaking, it’s only for train use. Coming in second is Norway’s Lærdal Tunnel, which spans 24.5 km.

Glaciers and fjords divide Norway into scattered settlements, so locals rely heavily on ferries and tunnels to shorten travel time. The country has an estimated 900 tunnels, with a combined length of around 750 km. For a nation with just 5 million people, that’s a very high ratio — including more than 30 undersea tunnels.

In such a long tunnel, is there a risk of drivers falling asleep? Though the 20-minute drive isn’t extremely long, this remains one of the challenges developers had to tackle.

To prevent drivers’ minds from wandering due to the monotony of a long tunnel, designers intentionally placed large caves every six kilometers to create visual transitions. They also used lighting variations — starting with white light as the base, complemented by blue and yellow lights to avoid visual monotony. Another challenge was “ventilation.” The Lærdal Tunnel is the world’s first tunnel equipped with an internal “air treatment plant,” located 9.5 km from the Aurland entrance, which helps expel dust and nitrogen dioxide.