Norway's aging E18 highway bridges at Sandvika may need to be completely demolished and rebuilt at a cost of 14 billion kroner, according to new calculations from the Norwegian Public Roads Administration. The staggering price tag is making a tunnel alternative under the Bærum town center appear far more economically rational. This potential shift could redefine a major national infrastructure project and alleviate years of traffic disruption for local residents.
A Costly Conundrum
New analyses from the Roads Administration conclude that the parallel three-lane bridges, constructed in the 1960s, are deteriorating beyond repair. "This is not about maintenance or upgrades. The bridges must be demolished and built completely new," said Tom Hedalen, project manager for the E18 development at the agency. He detailed the immense logistical challenges a rebuild would pose, including the need to construct a temporary bridge in the Oslofjord. "It would lead to a lot of traffic disadvantages for neighbors, Sandvika, and traffic management," Hedalen stated.
The core problem is a chemical reaction within the concrete itself. The Sandvika bridges are expanding due to alkali-silica reactions, which have caused damage and eventual fractures in the concrete pillars supporting the southern end of the structures. This degradation is so advanced that inspectors estimate the remaining lifespan of the bridges in their current state is only between 2035 and 2040. At Kadettangen, concrete has already fallen from beneath the bridge.
The Tunnel Alternative Gains Ground
The revelation of the 14 billion kroner rebuild cost dramatically changes the financial calculus for the entire E18 Bærum section. Previously, a tunnel was considered a more expensive option. Now, the Roads Administration indicates that boring under Sandvika appears to be the more socio-economically rational choice. A tunnel would avoid the years of extreme disruption a bridge demolition and construction project would inflict on one of Norway's busiest traffic corridors.
Bærum Mayor Lisbeth Hammer Krog of the Conservative Party hailed the new calculations as a breakthrough. "This is fantastic news and a clear breakthrough for a new E18 through Bærum," Krog said. She believes the updated cost assessment sets the stage for the tunnel project to be included in the forthcoming National Transport Plan, the government's key roadmap for infrastructure investment. Securing a place in that plan is essential for state funding and project realization.
The Ticking Clock of Concrete
The bridges' problems are not new but are accelerating. As recently as mid-January this year, the Roads Administration announced emergency weekend closures for urgent repairs. The ongoing alkali-silica reaction is a progressive condition, meaning the structures continue to weaken over time. This puts immense pressure on authorities to make a final decision on the replacement solution. Further delays could necessitate expensive interim safety measures or, in a worst-case scenario, force weight or lane restrictions on the vital artery linking Oslo to its western suburbs and the rest of the country.
The situation presents a classic infrastructure dilemma: choose the immediately disruptive but potentially simpler bridge rebuild, or invest in the more complex and initially costly tunnel that offers a long-term solution with less surface-level impact. The new cost data strongly tips the scales toward the latter. The tunnel option would not only bypass the failing bridges but could also reduce noise and pollution for Sandvika residents while freeing up valuable waterfront space for community use.
Political Momentum for a Tunnel
Mayor Krog's enthusiastic response underscores the local political will for a tunnel solution. For Bærum municipality, a tunnel represents an opportunity to heal the urban divide created by the current elevated highway, reconnecting the town center with the Oslofjord coastline. The significant cost of a bridge rebuild, now publicly quantified, provides a powerful argument for local and regional politicians lobbying the national government. Their case is that state funds would be better spent on a permanent, less disruptive solution that also enhances local environmental quality.
The final decision rests with the national government and parliament, which must approve the project and its funding. The Roads Administration's revised calculations will be a central document in that deliberation. The agency must now prepare updated proposals comparing the full lifetime costs, benefits, and impacts of both the bridge and tunnel alternatives. This work will be scrutinized by the Ministry of Transport and MPs in the Storting before any binding commitment is made.
A Decision with National Ramifications
The outcome of this process will resonate far beyond Bærum. The E18 is a critical European route and Norway's main coastal highway. Any multi-year construction project along this stretch would have cascading effects on regional commuting, freight logistics, and national mobility. The choice between bridge and tunnel will also set a precedent for how Norway handles its aging post-war infrastructure, much of which is reaching the end of its planned lifespan. The principles of socio-economic rationality, community impact, and long-term resilience highlighted in this case will apply to countless other projects in the coming decades.
With the bridges' condition worsening and a clear price tag now on the table, Norway's transport authorities face a pressing and expensive decision. The path forward, whether above ground or below it, will shape the region for generations to come. All eyes are now on the National Transport Plan process, where the future of Sandvika's crossroads will be decided.