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I-11 Boulder City Bypass

Boulder City, Nevada

Wildlife Crossing/Highway Underpass


CA Group, Inc.


Las Vegas Paving



Technical Description:

• Twin 72' x 25'-10" x 56' BEBO® Bridge Concrete Arch System
• 72' x 25'-10" x 32' BEBO® Bridge Concrete Arch System

A recent expansion of Interstate 11 in Southern Nevada connects Las Vegas to Phoenix. The new 4-lane, 15-mile-long section of highway improved motorist safety and convenience, while also reducing commutes by at least 30 minutes by allowing motorists to travel at higher speed limits while avoiding traffic signals in downtown Boulder City. The Nevada Department of Transportation (NDOT), along with the Regional Transportation Commission of Southern Nevada (RTC) started the $318 million project in April 2015 with different phases opening from August 2017 through May 2018. 

As part of the safety portion of the project, a solution was needed to keep wildlife off the highway. A twin 72' x 25'-10" BEBO® Bridge Concrete Arch System, 56' in length, was selected for its ability to provide safe passage for motorists below and wildlife, notably desert bighorn sheep, over the new stretch of highway. 8' tall perimeter fencing was added to encourage the wildlife to use the new crossing. Art Deco referencing the nearby historic Hoover Dam and its importance to Boulder City was Incorporated into the design of the bridge. 

“This has been a great project and example of interstate collaboration to assist in conserving and protecting desert bighorn sheep and wildlife,” said Jeff Gagnon, a research biologist with Arizona Game and Fish Department (AZGFD). “Barriers such as roadways can fragment wildlife habitat and impact their access to water. Through projects such as these, our collective goal is to do what we can to minimize such impacts by providing locations for wildlife to safely cross highways.”

With the expected addition of 32 million residents in the area between now and 2030, the expansion could not have come at a better time. It currently hosts 34,000 vehicles per day in addition to heavy truck traffic. 

"I-11 is critical to the continued economic vitality of Nevada," stated former Nevada Governor, Brian Sandoval, who currently chairs the State Transportation Board. "By improving traffic flow between Las Vegas and Phoenix, and providing relief to congested north-south highways like I-5 and I-15, the new I-11 will spur increased trade and commerce, advancing our economic development initiatives and ensuring we remain globally competitive."

A second BEBO bridge, 72' x 25'-10" x 38', was built at the interchange from the old highway alignment to the new freeway. It serves as a grade separation structure and as both a vehicular overpass and a vehicular underpass. Traffic under the bridge provides access to the Hoover Dam Visitor Center. 

Funding was provided by the Federal Highway Administration's (FHWA) Advance Construction program, allowing NDOT to be reimbursed up to $291 million (or nearly 92%) of the project-related costs. An additional $22 million was procured from Clark County's Fuel Reserve indexing funds and $5 million from the state.

Technical Description:

• Twin 72' x 25'-10" x 56' BEBO® Bridge Concrete Arch System
• 72' x 25'-10" x 32' BEBO® Bridge Concrete Arch System

800-338-1122 |


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