The Kerenzerberg Tunnel is a motorway tunnel

Tunnel

A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...

 in Switzerland

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

, and forms part of the A3

A3 (Switzerland)

The A3 is a motorway in northeast Switzerland, running diagonally from France toward the southeast border, and passing by Zurich on the way. The total length of the A3 motorway spans roughly , but parts of the road share sections of the A1 and A2 motorways....

 motorway from Basel

Basel

Basel or Basle In the national languages of Switzerland the city is also known as Bâle , Basilea and Basilea is Switzerland's third most populous city with about 166,000 inhabitants. Located where the Swiss, French and German borders meet, Basel also has suburbs in France and Germany...

 to Sargans

Sargans

Sargans is a municipality in the Wahlkreis of Sarganserland in the canton of St. Gallen in Switzerland.Sargans is known for its castle, which dates from before the founding of the Swiss Confederation in 1291...

. The tunnel is approximately 5.8 km long and it lies southwest of Lake Walen

Lake Walen

Walensee is one of the larger lakes in Switzerland, for about 2/3 of its surface in the Canton of St. Gallen and for 1/3 in the Canton of Glarus. It is also known as Lake Walen or Lake Walenstadt, after Walenstadt. Other towns and villages at the lake include: Weesen, Quinten, Quarten, and Murg.The...

.

The Kerenzerberg Tunnel is a one-way, unidirectional tunnel. Traffic from Zurich to Sargans must pass through the Kerenzerberg Tunnel, in the opposite direction the motorway runs along the shores of the Walensee through six short tunnels originally built for a railway. The railway now run through a 4 km tunnel. Transportation of dangerous goods through the Kerenzerberg tunnel is prohibited.