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 PHOENIX — The Arizona Department of Transportation (ADOT) has been recognized nationally for its creative and innovative solutions on a project that makes traveling safer for motorists, while protecting wildlife and connecting ecosystems. The Federal Highway Administration awarded one of its top environmental honors — the 2011 Exemplary Ecosystem Initiative Award — to ADOT for the successful completion of the US 93 Hoover Dam to milepost 17 project, which opened to the public before Thanksgiving in 2010. The project widened US 93 to a modern four-lane divided highway and includes three wildlife crossings for bighorn sheep in the Lake Mead National Recreation Area.

Upgrading a two-lane highway to an environmentally friendly four-lane divided highway was no easy task for project designers working on the $71.3 million project, which was the final piece to widening US 93 into a four-lane divided highway from Interstate 40 in Kingman to the new Mike O’Callaghan – Pat Tillman Memorial Bridge over Hoover Dam. The more modern, high-capacity highway allows traffic to move more safely and better meet needs in the future.

Standing in the way was the largest contiguous herd of desert bighorn sheep in the United States. Without a solution, motorists’ safety would be at greater risk because of an increase of wildlife-vehicle collisions and the animals’ ability to travel across the highway to reach resources necessary for the herd’s well-being and longevity would be threatened.

The obvious fix was to create wildlife overpasses that would allow the bighorn sheep to move back and forth across US 93 without getting in the path of fast moving highway traffic. But the question loomed where they should be built along this 15-mile stretch of new roadway.

To resolve this problem, ADOT worked with a number of state and federal agencies in a collaborative partnership to seek locations where desert bighorn sheep were most likely to cross the highway. The team was able to track these animals by placing electronic collars on them and use global positioning system tracking units to trace their movements over an extended period of time. This research helped identify the most appropriate crossing locations for the sheep.

“This project was truly a joint effort across multiple agencies including the Arizona Game and Fish Department, National Park Service, Bureau of Land Management and the Federal Highway Administration. Without their support and teamwork, we would not have been able to accomplish as much as we did,” said Todd Williams, director of environmental services for ADOT. “This new section of divided highway in this environmentally sensitive area delicately addressed two critical issues: the safety of the traveling public and the need to preserve the livelihood of the Desert Bighorn Sheep, which are native to the Black Mountains. These new wildlife overpasses helped accomplish both objectives on this project.”

Three specially designed overpasses for bighorn sheep, the first of their kind in Arizona and the lower 48 states, were constructed, along with fencing, as part of the highway expansion to reconnect and restore habitats, while promoting safety along the corridor. Shortly thereafter, cameras installed on the crossing bridges captured the desert bighorn sheep using the new overpasses, which are 100 feet wide and 203 feet long.

“ADOT continues to demonstrate excellence in preserving, restoring and enhancing wildlife connectivity that dramatically decreases wildlife-vehicle collisions,” said Karla S. Petty, Arizona Division administrator of the Federal Highway Administration. “The FHWA is very pleased with the state’s collaborative approach which engages the talent and knowledge of a multidisciplinary team.”

This is the second major award this project has received this year. In April, the Arizona chapter of the American Public Works Association named US 93 to Hoover Dam as the project of the year in transportation in the $25 to $75 million category.

For more information about this project, visit www.us93corridor.com.