The Granfoss Tunnel are two tunnels on Ring 3

Ring 3 (Oslo)

Norwegian National Road 150, also known as Ring 3 and formerly Store Ringvei is a beltway limited-access road which circumnavigates Oslo, Norway. It runs from Ryen, through the Sinsen Interchange to Lysaker in Bærum.-History:...

 in Oslo

Oslo

Oslo is a municipality, as well as the capital and most populous city in Norway. As a municipality , it was established on 1 January 1838. Founded around 1048 by King Harald III of Norway, the city was largely destroyed by fire in 1624. The city was moved under the reign of Denmark–Norway's King...

, Norway

Norway

Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

. The tunnels are 2.1 km long and they are part of the Granfoss Line, a 2.9 km stretch of motorway which was opened in 1992 connecting Ring 3 with the European route E18

European route E18

European route E18 runs from Craigavon in the United Kingdom to Saint Petersburg in Russia, passing through Norway, Sweden, and Finland. It is about 1,890 km in length.-United Kingdom:...

. The name comes from the Granfossen waterfall on the Lysakerelva river which passes nearby. The two tunnels run from Lysaker

Lysaker

Lysaker is a section of and a postal code area of the Norwegian municipality of Bærum, just west of Oslo.Geographically, it is bordered by Lysakerelven on the east, which also forms the border to Oslo; Fornebu to the south; Stabekk to the west; and Jar to the north...

 to Mustad, and from Mustad to Ullern Church, respectively.

When the two tunnels with four lanes were opened for traffic, a bottleneck of Oslo's road system which had lingered for several decades was finally dissolved. The tunnels were financed by Oslo Package 1

Oslo Package 1

Oslo Package 1 was a political agreement and plan for introducing an urban toll ring around Oslo, Norway, and making 31 investments to road infrastructure in Oslo and Akershus. The package was approved in 1988, and toll charges were introduced in 1990. It was supplemented by Oslo Package 2, which...

.

Despite there being two tunnels, the singular name is used in local parlance.