The Ryggedal Tunnel (, also known as the Bø Tunnel, ) is a road tunnel that is part of Norwegian County Road 820 on the border of Bø Municipality and ÃÂksnes Municipality in Nordland county, Norway. The tunnel is long.
Work on the tunnel was begun in 1977 under the leadership of the engineer Edward Pegg, and the tunnel was opened on October 17, 1980. Built at a cost of , this was the most expensive tunnel project in Norway until that time and also the most difficult. One-sixth of the tunnel has molded concrete vaulting.
Prior to the construction of the tunnel, Bø Municipality did not have any road connections to the rest of Norway. Residents of Bø used a ferry crossing between KrÃÂ¥kberget in Bø Municipality and Sandset in ÃÂksnes Municipality. Upon completion of the tunnel, the ferry crossing was closed.
Like many other tunnels in Norway, the Ryggedal Tunnel has condensation problems. Condensation can lead to dangerous situations because the pavement suddenly becomes damp when entering the tunnel. The tunnel's infrastructure was upgraded in 2015.