200-foot bridge spans six lanes, connects 39,000 acres of habitat

The overpass, which sits between the state’s two biggest cities, was designed to give large game an unobstructed view in each direction, with grass cover and gradually sloped entrances. The corridor between Denver and Colorado Springs is known for high movement of elk and other large animals. State officials said wildlife underpasses and tunnels often fail for those species because they restrict mobility and do not accommodate antlers.

Brandon Marette, a wildlife biologist for Colorado Parks and Wildlife, told CBS News that the moment the project crystallized for him came when transportation staff sent him a photograph. “One of the most heartwarming moments for me was when [Colorado Department of Transportation] sent me a picture of an elk mama taking her calf under [Interstate-25],” Marette said. “All came to fruition in that one moment. That elk with her calf was just standing there in safety.”

Chuck Attardo, the environmental manager for the Colorado Department of Transportation, told CBS News that pronghorn in particular had been searching the corridor for decades. “Elk and pronghorn like these big open structures where they can see for miles in each direction,” Attardo said. “For decades, pronghorn going from Trinidad to Greenland were looking for a place to cross on I-25. And when we open this up, we have pronghorn on video using the overpass, and for the first time in decades they’re coming over here to the west side.”

Wildlife biologists have documented not only large game but smaller species using the crossing. The list includes mule deer, coyotes, rabbits, frogs and the threatened Preble’s meadow jumping mouse.

The crossing joins a wider national buildout of similar infrastructure. Nearly 20 wildlife crossings are underway in the United States, and the Colorado overpass is currently the largest. Research has shown that overpasses are effective at “nearly eliminating” wildlife-vehicle accidents and that such infrastructure buildouts often “pay for themselves” by preventing costly crashes.

The Colorado Department of Transportation said it is hoping to build other wildlife crossings across the state.