It includes roads that are at least 1 kilometre (0.62 miles) long and whose culminating point is at least 2,000 metres (6,562 feet) above sea level.
Some of the listed roads are closed to motorized vehicles, although they are normally all accessible to pedestrians and cyclists.
These mountain roads are visited by drivers, motorcyclists, bicyclists and hikers for their scenery and often feature in the routes of European bicycle races such as the Giro d'Italia, the Tour de Suisse, the Tour of Austria, the Tour de France and the Vuelta a España.
It includes motorways whose culminating point is over 1,000 metres (3,281 feet) above sea level.
This is the highest road in the Alps but because of the maximum steepness of c. 30 % a suitable vehicle is needed.