The world's deepest tunnel costing £1.7bn where cars will drive for 16 miles beneath sea

The world's deepest tunnel could transport vehicles over 16 miles beneath the ocean. The Rogfast project in Norway is a 16.5-mile-long underground tunnel lying 392 metres (1,300ft) underneath the seabed.

The project, scheduled to open in nine years' time, will connect Stavanger and Bergen. Currently, drivers have to go along the E39 and embark on multiple ferry crossings. But it's claimed the tunnel will cut this journey in half.

In total the tunnel, construction of which began in 2018, is being split into three sections, each with their own ventilation and interchange systems so drivers can turn around and go the other way if necessary. It has been estimated that to drive the tunnel's full length at 50kph (31.25mph) will take around 35 minutes.

The infrastructure project, predicted to cost between £1.45bn and £1.74bn (€1.69bn to €2.03) is part of Norway's campaign to connect the country's west coast together. It will also improve transport links between the various towns and islands, reports Newsweek.

To create the tunnel, crews are removing around 8 million cubic metres of rock. The twin tunnels, set 50ft apart, will carry two lanes of traffic.

The area in which the route is situated is home to several key elements of Norway's economy including their seafood and oil industries.

It has been calculated that around 6,000 vehicles will use Rogfast once it starts operation with tolls expected on the road to help pay for its maintenance. The Norwegian government, meanwhile, is putting up 40 percent of the funding for the project.

These tolls could see intrepid drivers charged as much as £30 (€35.05), but this could change by the time the tunnel opens.

Speaking to Euronews about the benefits of the tunnel, project manager of the Rogfast project Oddvar Kaarmo said: "Stavanger is the fourth-largest city in Norway, and Bergen is the second largest.

"So we hope that it's possible that this project will be able to reduce traveling time for workers as well when they are traveling to either Stavanger or Bergen on a daily basis."

Mr Kaarmo added to the Telegraph: "The port at Mortavika is quite exposed and, in the winter, ferries sometimes have to divert to another port. Once the tunnel is finished, we will not have to rely on good weather to keep the roads open.

"About half a year after the last drill and blast, we have to deliver the project, so we have to get a lot of work done simultaneously. It's more about logistics than tunnelling."