The Nordby tunnel is 3,850 m long with two lanes in each direction in double pipes, while Smiehagen is 892 m with two lanes in one direction. The tunnels opened in 1993 and 1999 respectively, and are upgraded to comply with regulations. In the Nordby tunnel, fire safety and rock support will be improved. In the Smiehagen tunnel the road surface will be replaced and the drainage system repaired. A new purification plant that takes water from both tunnels will also be built.
Construction starts in August 2017 and the project will be completed in February 2019.
Skanska is one of the leading development and construction companies in the Nordics, with operations in building construction and civil engineering in Sweden, Norway and Finland, and developing residential and commercial property projects in select home markets. The commercial development stream is also active in Denmark. Skanska offers services in public-private partnerships. Skanska had sales of about SEK 67 billion and more than 15,000 employees in its Nordic operations during 2016.