Animals Are Using Utah’s Largest Wildlife Overpass Earlier Than Expected

The state will conduct a full analysis of the bridge after three to five years, but early results are promising

Photograph of the wildlife bridge over 6 lanes of traffic on Interstate 80
The wildlife crossing is about 50 feet wide and 320 feet long and is covered in rocks and logs. Courtesy of UDOT

Why did the moose cross Interstate 80? Because three-and-a-half miles of fencing guided it to Utah’s largest wildlife overpass.

Utah’s Department of Transportation completed the bridge in 2018, and new video from the state’s Division of Wildlife Resources shows dozens of animals using it to cross safely above six lanes of traffic, Leah Asmelash reports for CNN.

The overpass is 50 feet wide and 320 feet long, and its location was picked strategically based on animals’ migratory patterns, according to Atlas Obscura. Experts originally anticipated that local wildlife could take years to get used to the new, animal-friendly infrastructure, UDOT spokesman John Gleason told Park Records Angelique McNaughton in 2018. But in the last two years, cameras placed along the bridge’s guardrail captured footage of not only the expected deer, moose and elk, but also predators and small mammals.

Utah plans to conduct a full analysis of how the bridge has improved safety for wildlife—and people—after it’s been open for three to five years.

In a video posted on Facebook on November 19, viewers can watch moose, deer and elk trot across the bridge. In other clips, black bears wander up and down the path. And in another segment, a bobcat carries a small mammal in its mouth while walking across the bridge at night. Boulders and logs are strewn across the bridge to help it blend in with the landscape on either side and encourage animals to use it. And the animals do—a camera captured a big cat scratching and stretching on one of the logs.

“As you can see, the 2nd year of this overpass has been successful at helping wildlife safely migrate over busy Interstate 80 and helping motorists be much safer as well,” Utah’s Division of Wildlife Resources writes in the video’s caption.

In the two years before the overpass was built, UDOT recorded 106 collisions between vehicles and animals, which killed 98 deer, three moose, two raccoons, two elk and one cougar, per Scott D. Pierce at the Salt Lake Tribune. The count led the non-profit organization Save People Save Wildlife to dub the road section “Slaughter Row,” reports Park Record. The wildlife overpass was built as part of a larger UDOT project that also added a climbing truck lane and replaced several miles of asphalt.

The overpass incorporates over three miles of fencing stretching in both directions away from the bridge in order to guide wildlife toward the safe point to cross. After one year, the Utah Division of Wildlife Resources was surprised to see that cougars, coyotes, and yellow-bellied marmots had joined deer and moose crossing the bridge. This year’s footage shows bears and porcupines joined the mix.

“It's great to see so many different animals using the overpass,” said Utah Department of Transportation spokesman John Gleason to the Salt Lake Tribune in 2019.

The benefit is not just to animals, but to drivers as well. Gleason continued, “From what we can tell, the number of accidents there is down dramatically. At least initially, it appears the investment in safety is paying off. And we expected it to take several years before the animals got used to using it, so this is great.”

It will be a few more years until Utah has its official results of the I-80 overpass. But studies of wildlife crossings in Florida, Australia and Mexico have shown that they save both human and animal lives by preventing collisions.

“You can get reductions of 85 to 95 percent with crossings and fencing that guide animals under or over highways,” said Rob Ament, the road ecology program manager at the Western Transportation Institute at Montana State University, to National Geographic’s Starre Vartan in 2019.

But Utah’s Division of Wildlife Resources has repeatedly emphasized that the overpass is for animals only. Despite the warnings, guardrail cameras have spotted people walking and skiing across the new overpass, which is not only trespassing, but also puts people at risk of running into dangerous animals like moose, reported the Salt Lake Tribune.

“Please keep off of this overpass,” Utah’s Division of Wildlife Resources notes in the new video’s caption. The point of the overpass, after all, is to keep people and wildlife at a safe distance.

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