Norway is pushing the limits of engineering with Rogfast — a 27-kilometer (17-mile) undersea road tunnel that will become both the longest and deepest of its kind on the planet. When finished, it will plunge 392 meters (1,286 feet) beneath the sea, forming the backbone of a ferry-free highway along the rugged western coast.
Construction first began in 2018 but was paused a year later after costs ballooned. After a major reset of contracts and plans, the project restarted in 2021 and is now set for completion in 2033 with a price tag of around 25 billion Norwegian kroner ($2.4 billion).
According to Skanska project manager Anne Brit Moen, Rogfast will dramatically reshape travel between western cities. By replacing ferry links, the tunnel is expected to shorten the journey between Bergen and Stavanger by about 40 minutes and provide a far more reliable daily commute.
The design includes two traffic-only tubes with two lanes each — plus one of the most unusual features in any global tunnel: a 260-meter-deep double roundabout connecting to a spur tunnel leading to Kvitsøy island.
Engineering the structure has required some of the world’s most sophisticated surveying technology. Teams are tunneling from both ends and must meet with pinpoint accuracy — just 5 centimeters (1.9 inches) of allowable deviation. Laser scanners collect millions of data points per second to build a precise digital replica of the tunnel, helping crews detect even the slightest alignment issues.
Rogfast is one of the flagship projects of Norway’s overhaul of the 1,100-kilometer E39 coastal highway, which currently takes 21 hours to drive and relies on seven ferries. Norway’s long-term goal: eliminate the ferries entirely through a network of tunnels and bridges by 2050.
Yet the work is not without challenges. At 300 meters below sea level, construction crews have already encountered significant saltwater leakage, requiring advanced grouting techniques to keep workers safe. The tunnel will also integrate high-capacity ventilation systems, vertical shafts to Kvitsøy, live incident detection and vehicle monitoring via cameras and radar.
While some ferry-related jobs may disappear, Moen said Rogfast will ultimately strengthen regional economies, lower logistics costs for industries like seafood, and improve access to jobs and public services. It also creates substantial employment during construction.
Rogfast’s depth will dwarf other famous undersea tunnels, including Japan’s Seikan Tunnel and the Channel Tunnel — marking another ambitious milestone in Norway’s drive to conquer its dramatic coastline with cutting-edge engineering.
