A bridge–tunnel is a persistent, unbroken road or rail connection across water that uses a combination of bridges and tunnels, and sometimes causeways, and does not involve intermittent connections such as drawbridges or ferries.
Bridge–tunnels are a form of fixed link or fixed crossing which replaces ferry service. Fixed links are often, but not necessarily, intercontinental links between continents or transoceanic links to offshore islands.
The Chesapeake Bay Bridge–Tunnel (CBBT, officially the Lucius J. Kellam Jr. Bridge–Tunnel) is a 17.6-mile (28.3 km) bridge–tunnel that crosses the mouth of the Chesapeake Bay between Delmarva and Hampton Roads in the U.S. commonwealth of Virginia. It opened in 1964, replacing ferries that had operated since the 1930s. A major project to dualize its bridges was completed in 1999, and in 2017 a similar project was started to dualize one of its tunnels.
With 12 miles (19 km) of bridges and two one-mile-long (1.6 km) tunnels, the CBBT is one of only 14 bridge–tunnel systems in the world and one of three in both Hampton Roads and the United States. It carries US 13, which saves motorists roughly 95 miles (153 km) and 1+1⁄2 hours on trips between Hampton Roads and the Delaware Valley and points north compared with other routes through the Washington–Baltimore Metropolitan Area. As of January 2021, over 140 million vehicles have crossed the CBBT.
A fixed link or fixed crossing is a permanent, unbroken road or rail connection across water that uses some combination of bridges, tunnels, and causeways and does not involve intermittent connections such as drawbridges or ferries. A bridge–tunnel combination is commonly used for major fixed links.
This is a list of proposed and actual transport links between continents and to offshore islands. See also list of bridge–tunnels for another list of fixed links including links across rivers, bays and lakes.
Interstate 64 (I-64) in the US state of Virginia runs east–west through the middle of the state from West Virginia to the Hampton Roads region, for a total of 299 miles (481 km). From the West Virginia state line to Chesapeake, it passes through the major cities of Lexington, Staunton, Charlottesville, the state capital of Richmond, Newport News, Hampton, and Norfolk. It is notable for crossing the mouth of the harbor of Hampton Roads on the Hampton Roads Bridge–Tunnel (HRBT), the first bridge–tunnel to incorporate artificial islands, concurrent with U.S. Route 60 (US 60). Also noteworthy is a section through Rockfish Gap, a wind gap in the Blue Ridge Mountains, which was equipped with an innovative system of airport-style runway lighting embedded into the pavement to aid motorists during periods of poor visibility due to fog or other conditions.
The Hong Kong–Zhuhai–Macau Bridge (HZMB) is a 55-kilometre (34 mi) bridge–tunnel system consisting of a series of three cable-stayed bridges, an undersea tunnel, and four artificial islands. It is both the longest sea crossing and the longest open-sea fixed link in the world. The HZMB spans the Lingding and Jiuzhou channels, connecting Hong Kong and Macau with Zhuhai—a major city on the Pearl River Delta in China.
The HZM Bridge was designed to last for 120 years and cost ¥127 billion (US$18.8 billion) to build. The cost of constructing the Main Bridge was estimated at ¥51.1 billion (US$7.56 billion) funded by bank loans and shared among the governments of mainland China, Hong Kong and Macau.