The aim was to protect motorists and wildlife along an especially grisly stretch of highway. Now, it was time to see whether the investment would pay off.
Aran Johnson, a wildlife biologist for the Southern Ute Indian Tribe in the southwestern part of the state, walked up a bank to a newly constructed overpass crossing Route 160.
He’d been trying not to worry about the project. After all, the existing research was in his favor. But the thought still crept in: What if all the effort, over 15 years, turned out to be a failure?
50 States, 50 Fixes is a series about local solutions to environmental problems. More to come this year.
It was a cool summer morning in 2022, with mist rising from the ground. Mr. Johnson carried trail cameras. Mule deer and elk wouldn’t be showing up in any numbers until later in the year, when they had to cross the highway to reach their wintering grounds. Still, he wanted the cameras ready to capture the earliest evidence possible of any animals using the structure.
At the top of the overpass, he could barely believe what he saw: a line of hoof prints pressed deep into the fresh mud, stretching from one side to the other. An elk had already found its way across.
“To me, it was kind of a sign,” Mr. Johnson said.
Since then, it’s been one successful year after another. Entire herds of mule deer and elk use the structures, as well as bears, mountain lions, bobcats, coyotes and foxes.
Wildlife crossings are growing in popularity across the country, and in recent years, Colorado has emerged as a leader. Since 2015, it has built 28 new large game crossing structures, according to the state Transportation Department.
The state is rich in wildlife, and many of its species travel from higher elevations in the summer to lower ones in the winter, oftentimes crossing highways at great peril. In 2022, the General Assembly passed a law creating a cash fund for the department to use for animal crossings. Colorado has also evaluated its highways to create a priority list for future projects.
Wildlife crossings, when combined with long stretches of fencing to funnel animals to the right location, have been found to reduce vehicle collisions with large animals by more than 80 percent.
They are expensive, but research has shown they can save money when installed on stretches of highway with at least an average of three collisions between motorists and deer per mile per year. For collisions with elk and moose, which are bigger and therefore cause more damage to vehicles and people, that threshold goes down to less than one collision per mile per year.
Locals had long known they had to pay close attention when driving along that stretch of Route 160, near the Chimney Rock National Monument.
“I apologize for the gore, but it was littered with carcasses,” said Mark Lawler, a biologist with the Colorado Department of Transportation.
In the early 2000s, Mr. Johnson, the biologist for the Southern Ute, started collaring mule deer to better understand how they moved over the landscape around the reservation. He analyzed his data and superimposed them on state records of wildlife-vehicle collisions.
“It couldn’t be more perfect,” he said. “These things line up so precisely.”
The Colorado Department of Transportation, which covers the vast majority of the cost for wildlife crossings, agreed to put in an underpass on the reservation. But the Southern Ute also wanted to install an overpass, since certain species, particularly elk, seem to greatly prefer them. The tribe came up with $1.3 million from the Bureau of Indian Affairs to make that happen.
Additional funding for the $12 million project came from the state department of wildlife, nonprofit groups and even a private donor.
Mr. Lawler, the Transportation Department biologist, said Colorado has tried to emulate successes in other states and also share its own lessons.
“It’s a friendly competition,” Mr. Lawler said. “We’re all learning from each other.” Information isn’t the only thing shared. In some cases, the herds that use wildlife crossings move across state lines.
An added bonus of wildlife crossings is the photos that come from trail cameras, which help to bring attention to the programs, Mr. Lawler said. Here are some from another wildlife crossing project, along State Highway 9 in Grand County.
However, a potential hitch has surfaced: As the Trump administration cuts federal spending, a grant program that helps states and tribes pay for wildlife crossings in collision hot spots is now in doubt, including grants that had already been promised.
The Trump administration said the remaining grants were under review and that projects focused on relieving congestion and bolstering safety would be the priority.
Wildlife crossings transcend political divisions, said Patricia Cramer, an ecologist who consults with states on wildlife crossings, including the project on Route 160. They are popular among Republicans and Democrats. Of the two states she sees as national leaders, Wyoming is red and Colorado is blue.
For the Southern Ute, the crossings fit in with the cultural importance of being stewards of the land, said Andrew Gallegos, a member of the Tribal Council.
“This is one way to give back,” Mr. Gallegos said. “To help preserve life.”
