Norway has begun work on the E39 Rogfast, a road tunnel that will become the world's longest and deepest undersea tunnel, cutting journey times between major cities by 40 minutes.
Record-breaking dimensions
At 27 kilometres (17 miles) long, the tunnel will drop 392 metres (1,286 feet) below sea level at its lowest point — 83 metres deeper than the height of the UK's tallest building, the Shard. The name Rogfast is short for "Rogaland fastforbindelse," combining the local region's name with the Norwegian term for "fixed link."
The tunnel will form a key section of a ferry-free highway along Norway's west coast, linking Nord-Jæren and Haugalandet. The project is needed because the fjords plunge as deep as 400 metres below sea level, while the English Channel averages around 60 metres deep and reaches a maximum of 174 metres.
Challenging route
The E39 runs 1,100 kilometres from Trondheim in the north to Kristiansand in the south. Drivers currently face nine separate ferry crossings along the way, more than on any other single road in Europe, and the trip takes roughly 21 hours.
Travelling this route has been difficult for centuries. When the first postal service along the coast launched in 1647, postmaster Henrik Morian had to row across exposed fjords and then climb 1,500 metres up the opposite shore. According to B1M, snow and ice often made whole stretches impassable.
Safety and design
Norconsult, the lead design and engineering consultant on Rogfast, says the project is "groundbreaking in terms of tunnel length" and includes a junction in the middle of the tunnel for the exit to Kvitsøy, featuring a roundabout within the tunnel at an elevation of -250 metres. Because of the tunnel's great depth and length, plus a 7% gradient that raises the risk of engine burnout, fire is a serious concern. Emergency cross-passages will be placed every 250 metres, closer than the standard 330-metre spacing, allowing drivers to walk into a structurally separate parallel tunnel within minutes.
To address boredom, Norconsult's plans include an art project inside the tunnel "to prevent monotony, alleviate tunnel anxiety, shorten the perceived travel time, create a sense of orientation, and foster recognition," with dynamic lighting that may lead to adaptable and ever-changing solutions.
Construction timeline
After a false start in 2018, construction began in earnest in late 2021. Completion is scheduled for 2033, at an estimated cost of around 25 billion Norwegian kroner (£1.97 billion).
