Colorado Builds Largest Wildlife Overpass on I-25

Douglas County, CO — Construction crews are now building Colorado’s largest wildlife overpass above Interstate 25, marking a significant step in the state’s effort to protect wildlife and drivers alike.

The Greenland Wildlife Overpass, located between Monument and Larkspur, will span six lanes of busy highway, creating a safe corridor for large animals such as deer, elk, and pronghorn.

“This bridge is an invitation for wildlife to cross safely,” said the Colorado Department of Transportation (CDOT), which confirmed the crossing will have sloped entrances covered in native grasses to encourage animal use. The overpass is expected to open by December.

A conceptual image shared by CDOT shows a herd of elk moving across the green bridge above traffic.

Once completed, the overpass will connect 39,000 acres managed by the Douglas County Land Conservancy with more than one million acres of the Pike National Forest, creating a critical link between two protected habitats.

While Colorado already has over 100 wildlife crossings, most are underpasses. Only three current structures are overpasses designed for large mammals. According to CDOT, “larger animals like deer, elk and pronghorn prefer overpasses with clear sight lines” and typically avoid dark underpasses.

The project is part of the larger I-25 Gap project, which includes 18 miles of highway improvements and the addition of express toll lanes. Alongside the overpass, crews will build three more crossings and 28 miles of fencing to help reduce wildlife-vehicle collisions by an estimated 90 percent.

Why Wildlife Overpasses Matter

‍Wildlife-vehicle collisions cause hundreds of accidents in Colorado each year, leading to injuries, costly damage, and animal fatalities. Overpasses have proven highly effective in other states and countries, with research showing that properly placed crossings dramatically reduce accidents and support healthy migration routes for species that depend on large ranges.

A Model for Other States

‍Colorado’s success could inspire other states to invest more in wildlife connectivity. Advocates point to the economic and safety benefits, as well as the ecological importance of keeping habitats connected.

Looking Ahead

‍Once the Greenland Wildlife Overpass opens, CDOT plans to monitor its use with cameras and tracking data. Early signs of animal adoption could help secure funding for future crossings and expand the state’s leadership in wildlife corridor design.

Originally reported by Havalin Haskell in CPR News.