DOUGLAS COUNTY, Colo. — The largest wildlife overpass in North America is now complete and open to help animals safely cross Interstate 25 in Douglas County.
The Colorado Department of Transportation (CDOT) said the Greenland Wildlife Overpass project took less than a year to complete. Now, animals like moose, elk, pronghorn, deer, bears, mountain lions and others can use the overpass, which is covered in dirt and vegetation, to safely cross all six lanes of the interstate near Larkspur.
CDOT completed this project about 50% under the estimated cost.
Denver7 took an in-depth look at this project back in September 2024. We also explored other wildlife crossings across the state.
You can watch that report in the video below.
This wildlife overpass was named as one of the top priorities for the Colorado Wildlife & Transportation Alliance.
CDOT has built more than 40 wildlife underpasses and four overpasses, with more planned using state and federal dollars. Those crossings, paired with long stretches of wildlife fencing to funnel the animals to the safe passageway, have made an enormous impact: Reductions in wildlife-involved crashes hover around 90%.
That is expected to be the case with the Greenland Wildlife Crossing as well. Before the structure was built, that stretch had about one wildlife-vehicle crash per day in the fall and spring, when animals are moving around more, CDOT reported.
Larger animals like elk and pronghorn tend to feel more comfortable using an overpass instead of an underpass, which is why CDOT built this wildlife crossing above the highway.
Chuck Attardo with CDOT explained the need further during a 2024 interview with Denver7.
"We need that big honkin’ structure because the target species we're looking at are big trophy elk herds that use this area that are trying to go back and forth across I-25 in this area," he said.
The bridge structure is 200 feet wide by 209 feet long, but including the graded slope up to the overpass, the entire piece is about 400 feet long, CDOT told Denver7 in an email.
In 2024, this project was expected to come with a $30 million price tag, which then dropped down to about $20 million in July. CDOT said Tuesday the total cost was $15 million.
"The $30 million was an early estimate used for the federal grant proposal," explained Tamara Rollison with CDOT. "We were able to save money as we went through the design and construction process."
This project was one of 19 that the U.S. Department of Transportation funded through the Wildlife Crossing Pilot Program, which was created by the Bipartisan Infrastructure Law. That law made $350 million available over five years for the Wildlife Crossing Pilot Program, and $22 million of that went to building this wildlife overpass. The remaining $8 million — to reach the initial $30 million amount — came from CDOT and the Colorado Wildlife and Transportation Alliance via state Senate Bill 22-151 "Safe Crossings for Colorado Wildlife and Motorists." Denver7 is working to clarify the cost breakdown and what happens to the funds not spent.
More than 100,000 vehicles per day travel under the overpass.
The Greenland Wildlife Crossing is part of the I-25 South Gap project, which improved 18 miles of I-25 between Castle Rock and Monument.
“Colorado is leading the way in reducing wildlife-vehicle collisions, and improving safety for both our motorists and wildlife," said Gov. Jared Polis. "The I-25 Greenland wildlife overpass is a momentous feat, in our continued work to expand safe transportation options for both humans and wildlife, protecting critical habitat, and our amazing outdoor spaces for generations to come."
