"Rogfast" will be the world’s longest and deepest undersea road tunnel.

 

When completed, it will become the world’s longest and deepest undersea road tunnel. Stretching roughly 17 miles and plunging nearly 1,312 feet below sea level, Rogfast is designed to replace a key ferry crossing on the E39 coastal highway.

That highway runs for about 1,100 kilometers from Trondheim in the north to Kristiansand in the south. Today, the journey takes around 21 hours and requires seven ferry crossings. Rogfast alone will remove one of the longest and most vulnerable gaps, cutting about 40 minutes from travel between Stavanger and Bergen, Norway’s fourth- and second-largest cities. The project is supposed to be completed in 2033.

https://www.zmescience.com/science/news-science/world-longest-undersea-road-tunnel/