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.