U.S. Route 93 in Nevada portion of abandoned railroad right-of-way. A shopping center now sits where the original truck bypass alignment once ran. US 93 was realigned again on October 19, 2010, when the Mike O'Callaghan – Pat Tillman Memorial Bridge over the Black Canyon of the Colorado River opened to vehicular traffic. With that, the highway no longer passes over Hoover Dam, and the state-maintained portion of the replaced route was renamed as Hoover Dam Access Road (SR 172). In 2011, US 93 from Buchanan Boulevard to the Nevada terminus of the Hoover Dam Bypass was expanded to four through lanes with dedicated turn
Glen Canyon Dam be about . The general consensus among inhabitants of the Colorado River basin and government officials was that a high dam had to be built on the Colorado to control floods and provide carry-over water storage for times of drought. Possible locations for this dam were debated for years, and in fact the Bureau of Reclamation's first study for a dam at Glen Canyon was made in 1924, in addition to studies for locations at Black and Boulder Canyons lower on the Colorado, below Grand Canyon. These studies found that the lower Colorado sites had stronger foundation rock which might