Arizona Completes Highway Near Hoover Dam Bypass

Soil-Tech instrumental in beautifying the new four-lane highway between Nevada and Arizona.

The Arizona Dept of Transportation has completed the four-lane divided highway by the Hoover Dam bypass just in time for Thanksgiving. The new 15-mile stretch of US 93 provides a wider approach to the new Hoover Dam bypass bridge over the Colorado River, eliminating the notorious bottle neck.

Minor construction activities will continue through December but are supposed to affect only the off-roadway areas.

The $71.3 million highway project is part of the $240 million Hoover Dam bypass project that includes the Mike O’Callaghan- Pat Tillman Memorial Bridge, which links the states of Nevada and Arizona downstream from Hoover Dam. The bridge was opened on Oct. 14, 2010.

Spanning nearly 2,000 ft, the bridge is named after Mike O'Callaghan, a highly decorated Korean War veteran and former governor of Nevada, and American hero Pat Tillman, an Arizona Cardinals football player who gave up a multi-million dollar career at the NFL to fight in Afghanistan and was killed by friendly fire.

This second highest bridge in the US wasn’t an easy project to complete. The project began in January 2005. To start with, 3.5 million cubic yards of earth had to be removed. The construction of the bridge required 243 million tons of concrete and 16 million pounds of steel to reinforce concrete. The arches, which are the largest in the Western Hemisphere, were engineered at 900 ft above the Colorado River and built in 24-foot long concrete increments. The high-line crane system which utilized 2,300-foot long steel cables to hoist workers and materials collapsed on September 18, 2006 due to high winds in the area, causing a two year delay in the project. Winds of up to 55 mph in Las Vegas Valley that day are attributed by engineers as the cause of the accident, which did not result in any deaths or injuries.

Much had to be done to improve the highways around the bridge. On the Nevada side, the project included 2.11 miles of new four-lane highway alignment that included six new bridges, a new US 93 traffic interchange, 50,000 square feet of retaining walls, wildlife crossings and a 1.6 mile extension of the River Mountain Loop hiking trail. On the Arizona side, it involved constructing a 1.8 mile long four-lane roadway, a 900 ft long bridge, a new traffic interchange to connect to the US 93, wildlife crossings, hiking trail access parking, and new drainage structures.

With such massive construction, all stakeholders wanted to ensure that the project had as little impact on the environment as possible. Soil-Tech, Las Vegas-based environmental services company, was hired to restore the natural look for the desert with the company’s patented Permeon simulated desert varnish. As the sun oxidized the treated areas, they take on a natural aged appearance with no impact on vegetation or wildlife. Several wildlife overpasses were built to help restore habitats.

According to estimates made by the Federal Highway Administration, the economic impact of not building the bridge would have cost $100 million annually in commute time and gas. The Hoover Dam bypass will be instrumental in improving the traffic between Phoenix, Ariz. and Las Vegas, Nev., playing a vital role in interstate commerce.

Soil-Tech/Native Resources is the largest licensed environmental services company in Nevada. For case studies of environmental friendly practices in large construction projects, go to