2.5 billion krone. In addition to a general increase in construction costs, a major calculation error had been carried out based on estimates for a light rail, rather than a rapid transit. At the time of closing the estimates called for completion in 2011. An audit in 2010 concluded that the planning had been based on lack of reviews and risk management, with best-case estimates being used instead of properly risk-adjusted ones. Bærum Municipal Council rejected a proposition in 2010 to build additional housing in the vicinity of the metro stations. The next section to open was to Bjørnsletta, on 18 August 2010. It was built in a new location, replacing the old station with the same name and Lysakerelven. This was followed by an extension of Jar 1 December. At the same time the tramway services were extended from Lilleaker to Jar. Another extension took place on 15 August 2011, to Bekkestua. Tjernsrud, the old Ringstabekk and Egne hjem were all closed and replaced with a new Ringstabekk Station. The route had been proposed slightly changed across Jarmyren, but lack of funding resulted in the old route being used, limiting speed to . The extra cost of allowing trams to run to Bekkestua was 500 million kroner. On 8 October 2012 the line was extended to Gjønnes, the shortest of the sections to open. From 9 December 2012 the Kolsås Line was renumbered Line 2 and instead linked to the Furuset Line. Services were extended to Avløs on 15 December 2013. The rebuilding of Haslum resulted in the demolishment of several houses, while Avløs Station was moved somewhat westwards. The final stage was officially reopened on 12 October 2014. Valler and Gjettum was merged and the new Gjettum Station replaced them. The project also included a full upgrade of Avløs Depot, completed in August 2015. As of 2012 the costs for the metro upgrades is estimated at 2.9 billion kroner. The line was again renumbered to Line 3 and linked with the Østensjø line on 3 April 2016. Future Rykkinn is a neighborhood in the vicinity of Kolsås, an area with about 7,500 residents. Extension of the Kolsås Line to Rykkinn, possibly with a further extension to Bærums Verk, has been proposed. Several routes to Rykkinn have been proposed along various trajectories, normally with three stations. Some of these include routes in a tunnel. A light rail report was