The tunnels are bored through the Xueshan Range. The road connects Taipei through New Taipei to Yilan County, cutting down the journey time from two hours to just half an hour. It bypasses the rural district of Pinglin, which used to receive high traffic prior to the completion of the tunnel. One of the key aims of constructing the tunnel was to connect the western coast of Taiwan, where 95% of the population lives, to the eastern coast of the island and in doing so tackle the unbalanced development on the island. It is constructed with one pilot tunnel and two main tunnels for eastbound and westbound traffic. The total length is , making the Xueshan Tunnel the ninth longest road tunnel in the world (fifth at the time of opening) and sixth longest in East Asia. The tunnel opened in June 2006 to severe traffic jams.