The Simplon road, which connects Brig, Switzerland, with Domodossola, Italy, is the only road crossing the Alps that is open all year round and on which the transportation of hazardous materials is authorized. The route is some 65 km long and presents uphill and downhill gradients of up to 9% along stretches of road some 20 km long on both the northern and southern sides. This makes the Simplon road unique among European international road axes.

The Swiss stretch of the road is a category 3 national road (mixed traffic), which since 2008 belongs to the Swiss Confederation. The department of roads and waterways of the canton of Valais has been commissioned by the Federal Roads Office (FEDRO) to ensure road maintenance and winter services.

Engineering structures:

• Bridges: 59
• Galleries: 21
• Tunnels: 11
• Total number of structures: 91