The twisting road on the pass has long been a challenge for drivers traveling between the cities of Huế and Đà Nẵng. Since the completion of Hải Vân Tunnel, traffic flow and safety have improved. The pass has been the scene of at least two of Vietnam's most serious rail accidents, and at least one air crash.
The pass is crossed by two main transport routes: Vietnam's main north–south highway, National Route 1A, and the North–South Railway. The road crosses over the mountain more or less directly, climbing to an elevation of 496 m (1,627 ft) and passing south of the 1,172 m (3,845 ft) high Ai Van Son peak, while the railway hugs the coastline more closely, passing through a series of tunnels along the way. Since its opening in 2005, the Hải Vân Tunnel—the longest tunnel in Southeast Asia—offers an alternative road across the pass, reducing travel times by at least an hour.
According to VietKings (Kyluc.vn)