Find out all the details about this extreme engineering project. Norway is not only building a road, but also creating an underwater legend: the Rogfast. This megaproject is the ultimate expression of modern engineering, destined to break records for the length and depth of any known road tunnel. This bold infrastructure crosses the deep waters of the Boknafjord, with the strategic aim of creating a direct land link between Randaberg and Bokn. Historically, this region depended on the constant use of ferries to ensure the mobility of its citizens and goods.
Norway is building the world’s longest and deepest underwater tunnel: it will connect islands and continents
Rogfast is not an isolated project. It is part of the plan to complete the construction of the E39 motorway, a strategic route 1,100 kilometres long that will connect northern and southern Norway without sea crossings. Within this corridor, the tunnel is considered the greatest technical challenge. With a length of 26.7 kilometres and a section that descends 392 metres below sea level, the future road will reduce the current travel time to 35 minutes, thanks to two parallel tubes with one-way traffic. The estimated cost exceeds 20.6 billion Norwegian kroner, equivalent to more than 1.7 billion euros. Although work was suspended in 2019 due to budget overruns, construction resumed in 2021 and continues uninterrupted today, with the aim of opening the passage to transport in 2031 and completing full operation in approximately 2033.
Underwater excavation: the most complex stage of the project
The technical complexity of the project is enormous. Excavation is carried out in layers of gneiss, granite and fractured zones, which require constant reinforcement. The process uses the drilling and blasting method with robotic equipment, which transports explosives daily to continue advancing into the rock. Each blasting operation requires careful ventilation, stability measurement and debris removal before a new cycle can begin. Added to this is the construction:
- Underground passage 250 metres deep to connect to the island of Kvitsey.
- Networks of cross passages every 250 metres to ensure safety and evacuation.
- High-performance ventilation systems capable of controlling air, pressure and smoke in one of the deepest underground spaces on the continent.
It is estimated that, in the end, 10 million cubic metres of rock will be extracted, which is already being used in regional construction works and coastal projects.
