A drive on the main coastal artery, E39, from Stavanger to Sogneford is less than 250 miles, but takes more than seven hours, traversing as it does countless high-cliffed glacial inlets carved miles into the coasts.

To complete the entire 680-mile drive under current conditions, you would have to allow 21 hours for travel and include eight ferry trips since Norway’s fjords are too deep and too wide to support bridges.

A project by the Norwegian Public Roads Administration poses a possible solution to that problem: floating underwater tunnels.

The tunnels could cut trip time to 10.5 hours by reducing the need for ferry rides. The project is expected to be completed by 2023. Each tunnel would be suspended under 100 feet of water, held up by pontoons on the fjord’s surface and possibly an anchor bolted to the bedrock. Each fjord would be equipped with two tunnels: each two-lane, one for traffic flowing in each direction.

Underwater tunnels aren’t a new idea for Norway. The country has 1,150 traffic tunnels, 35 of which are located under shallow bodies of water. Fjords, however, can be a mile deep, creating a challenge for conventional tunnels.

The floating underwater tunnels will allow boats to still traverse the fjord without the worry about hitting or being blocked by a bridge.

But there’s still a long way to go before floating underwater tunnels become reality. Engineers have several questions to answer, including how wind, waves and currents will affect the structures. If the tunnels prove too difficult, Inhabitat reported, politicians have the right to send the funding to another project.

The following Norwegian Public Roads Administration video offers more information about the project: