Hai Van Tunnel is a key road tunnel project on National Highway 1, connecting Hue City and Da Nang City. The project contributes to strengthening the North–South transport corridor and enhancing transport capacity through Hai Van Pass. Hai Van Tunnel 1 was opened to traffic in June 2005, while Hai Van Tunnel 2 officially commenced operations in January 2021, forming a modern twin-tunnel system that accommodates growing traffic demand while ensuring safe and efficient traffic flow along the route.