The Hoover Dam Bypass, which opened for vehicle traffic in 2010, diverts traffic from United States Highway 93 to relieve congestion. The rather short bypass allows through traffic to avoid the Hoover Dam area, which is frequented by sightseers. The construction of the bypass included the building of a bridge over the Colorado River.
Since being designated as a North American Free Trade Agreement route, United States Highway 93 has experienced considerable traffic congestion. The increased amount of traffic when combined with the heavy restrictions at the dam crossing had slowed traffic dramatically. The Hoover Dam Bypass is designed to alleviate the increased traffic flow. The 3.5 mile (5.6 km) corridor connects Clark County, Nevada and Mohave County, Arizona.
Pedestrian and sightseeing traffic combined with increased security measures following the 11 September 2001 terrorist attacks led to a need for a safer crossing which would reduce a possible attack on the dam and alleviate the congestion of traffic. Since its opening on 19 October 2010, the Hoover Dam Bypass has significantly reduced traffic flow at the dam crossing. Travelers and commercial traffic can now bypass the inadequate two-lane dam crossing, leaving it to sightseers and slower traffic.
The Hoover Dam Bypass crosses the Colorado River some 1,500 feet (about 457 m) south of the Hoover Dam via the Mike O'Callaghan-Pat Tillman Memorial Bridge, formerly known as the Colorado River Bridge. The bridge's length is about 2,000 feet (610 m) long and spans the canyon some 900 feet (274 m) above the Colorado River. The bridge connecting the Arizona and Nevada highways was the first concrete-steel composite bridge constructed in the United States.
Approximately 17,000 vehicles use the new Hoover Dam Bypass daily. The amount of traffic is expected to increase over 50 percent in the next 20 years as people become accustomed to it. Other factors that should add to traffic on the Hoover Dam Bypass include the expected increase in population and trade. Work began on the bypass in early 2003 and was not complete until 14 October 2010. Pedestrian, bicycle and vehicular traffic followed in the ensuing days.
The bridge was named in honor of two of the area's respected citizens. Mike O'Callaghan was a decorated Korean War veteran who later became the Governor of Nevada between 1971 and 1979, and died in 2004. Pat Tillman played professional football for Arizona State University and the Arizona Cardinals of the National Football League. He declined a multi-million dollar contract to play football so he could enlist in the U.S. Army after the 11 September 2001 terrorist attacks. He lost his life in 2004 when he was killed by friendly fire in Afghanistan.