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Tingstadstunneln (Tingstad Tunnel) is a motorway tunnel under the Göta älv, connecting 
Hisingen
Hisingen () is the fifth-largest island of Sweden (after Gotland, Öland, Södertörn and Orust), with an area of . It is a river island, formed by the split of the Göta Älv at Bohus, and is defined to the east and south by the main arm of tha ...
with mainland Gothenburg
Gothenburg (; abbreviated Gbg; sv, Göteborg ) is the second-largest city in Sweden, fifth-largest in the Nordic countries, and capital of the Västra Götaland County. It is situated by the Kattegat, on the west coast of Sweden, and has ...
. The tunnel was constructed with two parallel immersed tubes with three lanes of traffic in each tube. It is part of the E6 route linking Norway with south-west Sweden.
Construction started on 17January 1961, and the tunnel was inaugurated at 11:30 am on 29March 1968.
The tunnel has the lowest motorway elevation in Sweden, at below sea level (nearby Götatunneln is lower and designed like a motorway but not signposted as one).
The tunnel has severe traffic congestion problems since several years, so therefore a new tunnel is built a little farther north, Marieholmstunneln, to be opened in 2020.
References
Buildings and structures in Gothenburg Undersea tunnels in Europe Road tunnels in Sweden Tunnels completed in 1968 Hisingen Immersed tube tunnels in Sweden 1968 establishments in Sweden {{Europe-tunnel-stub