Colorado officials on Tuesday proudly announced the completion of the I-25 Greenland Wildlife Interchange in Douglas County. Spanning six lanes of a busy interstate highway, the bridge is 209 feet long, 200 feet wide and has a surface area of nearly an acre, making it the largest wildlife crossing ever built in North America and one of the largest in the world.
After nine years of planning and construction, crews put the final touches on the building earlier this month, covering the surface with dirt and planting seeds. Douglas County Commissioner George Till called its completion a “huge milestone” in protecting wildlife habitat and protecting public safety.
A worker spreads seeds on a bridge structure covered in dirt. Photography: CDOT
The bridge is located on a heavily trafficked stretch of road near Larkspur, near the midpoint between Denver and Colorado Springs, the state’s two most populous cities. (About 100,000 vehicles travel this stretch of road every day.) This part of the Front Range is also an important migration corridor for large animals.
In other words, it’s a recipe for roadkill. According to the Colorado Department of Transportation, there is an average of one wildlife-vehicle collision per day in the region during the spring and fall. CDOT now expects the new crossing will reduce crashes by about 90 percent. This is consistent with past research in Banff National Park, where a series of wildlife crossings helped reduce wildlife-vehicle collisions by 80 percent, with elk and deer alone reduced by 96 percent.
“Colorado Parks and Wildlife is excited that Colorado’s wildlife will be able to utilize this overpass,” Matt Martinez, CPW regional wildlife manager, said in a news release Tuesday. “We look forward to deer, elk, bears, cougars and many other species safely crossing Interstate 25, once a major barrier to migration and wildlife movement.”
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The crossing was designed with elk and pronghorn in mind, the California Department of Transportation said. These species and others, such as black-tailed deer, prefer open overpasses to the narrow underpasses favored by mountain lions and black bears.
Because of the unseasonably warm weather the Front Range Mountains have experienced this winter, CPW officials said large animals have not yet started using the pass. But they expect that to change when snow starts pushing animals down from higher ground.
Officials said the project, which cost about $15 million, was completed ahead of schedule and on budget. Much of the funding comes from federal grants from the Wildlife Crossing Pilot Program established during the Biden administration.
