World’s longest road tunnel gets a makeover

The world’s longest road tunnel is getting an overhaul. Skanska has signed a NOK 1.6 billion contract to upgrade the 24.5-kilometre Lærdal Tunnel in Norway, after a court dismissed a rival’s attempt to block the deal.

Skanska has signed the contract to upgrade the Lærdal Tunnel in Norway after a legal challenge by rival contractor Oneco Infra was dismissed by Oslo District Court. The tunnel, at 24.5 kilometres the world’s longest road tunnel, is a vital transport link between eastern and western Norway.

The upgrade covers extensive renovation and modernisation of technical and safety systems to ensure continued efficient traffic flow between Bergen and Oslo.

Oneco Infra had attempted to invalidate the contract award, arguing that Skanska lacked qualified project managers. Oslo District Court rejected the claim, ruling that Skanska’s project manager met the minimum requirements set out in the tender documents.

The work will be carried out while the tunnel remains largely open to traffic, placing significant demands on planning and logistics. Construction is planned to start in November 2026, slightly delayed by the legal process. Oneco Infra still has the option to appeal.

The project is expected to be completed in 2029. The contract is worth approximately NOK 1.6 billion.

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