Tunel de Vielha is a steep tunnel in the Pyrenees

The Vielha tunnel is a high mountain tunnel at an elevation of 1.635m (5,364ft) above the sea level, located in the Pyrenees, in north-west Catalonia, Spain.

The tunnel is 5km long. The road traversing the tunnel is called N230. It’s asphalted but with some pretty steep sections, up to 7.5%. The tunnel consists of 2 parallel tunnels. The older one, named Alfonso XIII Tunnel, was opened in 1948 and became the longest road tunnel in the world, in that time, with a length of 5.24km. The new tunnel, named Juan Carlos I Tunnel is 5.23km long and was opened in 2007. The old tunnel is currently used as an emergency exit and is used by trucks which carry flammable or otherwise dangerous products.

Open to traffic throughout the year, may be closed for short periods in winter when the weather is bad. There are 2 routes to reach the summit of the tunnel. Starting from Vielha, the ascent is 12.3 km long. Over this distance, the elevation gain is 664 meters. The average percentage is 5.4 %. And starting from Villaler, the ascent is 18.7 km long. Over this distance, the elevation gain is 656 meters. The average percentage is 3.5 %.