The increases in costs for the E4 Bypass Stockholm have arisen from factors such as more complex tunnelling conditions than originally expected. Carrying out the construction of the tunnels running under Lovö has proven more challenging than anticipated. The work was also set back by the cancellation of the tunnelling contract with the original builder of the tunnels.
The bypass was originally due for completion in 2026 but will now take until 203 to be ready for use. The project is being managed by the Swedish Transport Administration (Trafikverket), which says that the new link will connect the southern and northern parts of the Stockholm county and relieve the arterial roads and the inner city of traffic.
A new link west of Stockholm has been considered for several decades and a large number of alternatives have been studied. To reduce the impact on sensitive natural and cultural environments, just over 18km of the total of 21km of the link lie in tunnels.
The construction work for the first main contracts started in 2015. By 2035, Trafikverket estimates that the Stockholm bypass will be used by approximately 140,000 vehicles/day.