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he San Francisco – Oakland Bay Bridge (known locally as the Bay Bridge) is a pair of bridges spanning San Francisco Bay of California, in the United States. Forming part of Interstate 80 and of the direct road route between San Francisco and Oakland, it carries approximately 270,000 vehicles per day on its two decks. It has one of the longest spans in the world.

The Mike O'Callaghan – Pat Tillman Memorial Bridge, the key component to the Hoover Dam Bypass project, was the first concrete-steel composite arch bridge built in the United States, and it incorporates the longest concrete arch bridge in the Western Hemisphere. Opened on October 19, 2010, this four-lane highway bridge provides a crossing of the Colorado River for U.S. Route 93, linking Nevada with Arizona about 1,600 feet (about 500 meters) downstream from the Hoover Dam. This bridge is located about 30 miles (48 kilometers) southeast of Las Vegas, Nevada. At 840 feet (260 meters) above the Colorado River, this bridge is the second-highest one in the United States, following the Royal Gorge Bridge. Built as part of the Hoover Dam Bypass Project, which was successfully completed within budget at a cost of $240 million, the bridge portion cost $114 million (2010 prices).