By Charlotte Reid 
When we think of tunnels, bridges and record-breaking engineering projects, we always remember projects built in China, but the project we are showing you today is located in Europe.
Following on from the Fehmarn Belt, which we talked about a few months ago, the Rogsfast project is now gaining momentum. It is the longest and deepest undersea tunnel in the world, located in Stavanger, Norway. The E39 Rogsfast project is currently under construction in south-western Norway and is set to become an important milestone in the development of civil engineering.
This road tunnel, which is being promoted by the Norwegian Public Roads Administration (Statens vegvesen) as part of an initiative to create a ferry-free E39 coastal route, will break several records in terms of length and depth.
Currently, the entire 1,090-kilometre E39 route between Trondheim and Kristiansand takes 21 hours and includes seven ferry crossings. The Rogfast tunnel will connect the municipality of Randaberg with Lauppland in Bokn, linking the regions of Nord-Jæren and Haugalandet and reducing travel time from 20 to 11 hours.
Unprecedented dimensions under the sea
Once the E39 Rogfast project is completed, several key world records will be set:
The longest undersea road tunnel: the main section under the sea will be approximately 27 kilometres long, surpassing any road tunnel currently in regular use.
The deepest road tunnel in the world: its maximum depth will be 392 metres below sea level.
The longest and deepest four-lane tunnel: at approximately 27 kilometres, it will be the longest and deepest four-lane tunnel on the planet.
Deep underground transport interchange: the project includes a ring interchange in the centre of the tunnel, providing access to a 4-kilometre branch to the island of Kvitøy. This interchange will be located 250 metres below sea level.
A colossal undertaking
The entire project covers approximately 60 kilometres of tunnel, designed to handle approximately 13,000 vehicles per day per year. The toll for each vehicle will be approximately €30.
In addition to the engineering challenges of ventilation and emergency response measures for a tunnel of this scale, Rogfast incorporates innovative elements into its design and sustainable development.
Rogfast Pluss, as the sustainability initiative is called, aims to implement measures to reduce energy consumption and greenhouse gas emissions, collect energy (wind, solar, geothermal), minimise the use of materials, and improve the environment and agriculture in the project’s area of influence.
In addition, an art project using dynamic lighting will be implemented inside, with the aim of combating monotony, reducing driver anxiety and improving the perception of travel time.
The project, whose planning and design phase will run from 2011 to 2032, began construction on its first major contract in autumn 2021; the estimated construction period will be approximately eight years.
Once completed, it will officially become the longest and deepest undersea tunnel in the world: it will be 27 km long and have a maximum depth of 382 metres.