Anyone who has driven Interstate 25 between Denver and Colorado Springs knows that traffic can get… hairy. And it’s not just drivers whose safety is at risk, as animals like elk, bears, coyotes, and more also need to use the highway to access 39,000 acres of habitat. Cars and pronghorns just aren’t compatible. That’s why Colorado Department of Transportation (CDOT) set out to build a wildlife-only bridge, the largest of its kind currently in North America, which it completed in December 2025. Within the first nine months since its opening, wildlife-vehicle collisions were already down a whopping 91 percent.

Before the crossing opened, dozens of animals were killed by vehicles every year, often up to one per day during migration seasons. The overpass spans I-25’s six lanes and is completely covered in grass so that critters have uninterrupted access to habitat on both sides of the highway—and drivers face less risk and expense due to collisions. The project is one of several in progress across the U.S., including a handful more in Colorado that include underpasses and smaller bridges. Brandon Marette, a wildlife biologist with Colorado Parks and Wildlife, told CBS News, “One of the most heartwarming moments for me was when CDOT sent me a picture of an elk mama taking her calf under I-25.”