Colorado wildlife overpass cuts vehicle-animal collisions by 91 per cent

Bridge over Interstate 25 connects 39,000 acres of habitat and draws elk, bears, pronghorn and frogs

By LineZotpaper

Published19 October 2026

Read Time2 min

A grass-covered wildlife overpass spanning six lanes of Interstate 25 in Colorado has cut vehicle-animal collisions by 91 per cent since opening 10 months ago, according to a new report from state officials, who have tracked elk, bears, pronghorn and even northern leopard frogs using the crossing.

The Colorado department of transportation said the corridor had previously averaged about one wildlife-vehicle crash a day before the overpass was built. The structure sits between Denver and Colorado Springs, stretches 200ft wide and 209ft long, and connects 39,000 acres of habitat on either side of the interstate, with gradually sloped entrances to ease animal crossings.

"One of the most heartwarming moments for me was when [the department of transportation] sent me a picture of an elk mama taking her calf under [Interstate-25]," Brandon Marette, a wildlife biologist for Colorado parks and wildlife, told CBS News. "All came to fruition in that one moment. That elk with her calf was just standing there in safety."

Officials say wildlife underpasses and tunnels often do not work for large animals such as elk, because they restrict mobility and cannot accommodate antlers. "Elk and pronghorn like these big open structures where they can see for miles in each direction," said Chuck Attardo, environmental manager for the department of transportation. He said pronghorn had been looking for a place to cross I-25 for decades, and that for the first time in decades they now appear on video crossing to the west side.

Smaller species have also been recorded using the crossing, including mule deer, coyotes, rabbits, frogs and the threatened Preble's meadow jumping mouse. The project received $22m in federal funding and $8m from the state, though officials said it was completed for about $15m.

Nearly 20 wildlife crossings are under way across the United States, with the Colorado structure currently the biggest. Research has shown overpasses can "nearly eliminate" such accidents and often "pay for themselves" by preventing costly crashes. The department now hopes to build further wildlife crossings across the state.

Analysis

Why This Matters

Collisions between vehicles and wildlife cause injuries and deaths to both people and animals, and this overpass cut them by 91 per cent in its first 10 months.
The structure is part of a national trend: nearly 20 wildlife crossings are under way across the United States, with Colorado's currently the largest.
Research suggests such crossings often pay for themselves by preventing costly crashes, which could encourage further investment.

Background

Wildlife crossings, both overpasses and underpasses, are structures designed to let animals cross busy roads safely and to reconnect habitats split by highways. They have been used for decades in various countries. The new Colorado overpass spans six lanes of traffic and links 39,000 acres of habitat on both sides of the interstate, in a region known for heavy movement of large game.

Key Perspectives

[Colorado transportation officials]: They celebrate the reduction in collisions and hope to build more crossings across the state, noting that large, open structures suit elk and pronghorn, while underpasses and tunnels can restrict mobility and fail to accommodate antlers. [Wildlife biologists]: They point to the crossing's value for many species, from elk and bears to mule deer, coyotes, rabbits, frogs and the threatened Preble's meadow jumping mouse. [Skeptics]: Cost remains a consideration: the project drew $30m in committed federal and state funding and was completed for about $15m. Design matters too, since underpasses do not suit all species.

What to Watch

Whether additional crossings planned across Colorado achieve similar reductions.
Whether the 91 per cent collision cut is sustained as traffic patterns and animal movements evolve.
Continued monitoring of the full range of species using the corridor, including the threatened Preble's meadow jumping mouse.

Sources

Colorado wildlife overpass cut vehicle-animal collisions by 91%, report finds · World news | The Guardian

Checked

12 claims in this story checked against 1 source: 12 supported.

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SupportedColorado wildlife overpass cuts vehicle-animal collisions by 91 per centWorld news | The Guardian: “cut wildlife-vehicle collisions by 91% since its completion 10 months ago”
SupportedBridge over Interstate 25 connects 39,000 acres of habitatWorld news | The Guardian: “connects 39,000 acres of habitat on both sides of the interstate”
SupportedBridge over Interstate 25 draws elk, bears, pronghorn and frogsWorld news | The Guardian: “officials have tracked herds of elk, bears, pronghorn and even northern leopard frogs ambling across its new wildlife overpass”
SupportedThe overpass has cut collisions by 91% since opening 10 months agoWorld news | The Guardian: “cut wildlife-vehicle collisions by 91% since its completion 10 months ago”
SupportedBrandon Marette told CBS News: 'One of the most heartwarming moments for me was when [the department of transportation] sent me a picture of an elk mama taking her calf under [Interstate-25]'World news | The Guardian: ““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],” Brandon Marette, a wildlife biologist for Colorado parks and wildlife, told CBS News.”
SupportedThe Colorado department of transportation said there was an average of one wildlife-vehicle crash per day before the overpassWorld news | The Guardian: “The Colorado department of transportation said before the overpass being built, there was an average of one wildlife-vehicle crash a day in this corridor.”
SupportedThe structure stretches 200ft wide and 209ft longWorld news | The Guardian: “measures 200ft wide and 209ft long”
SupportedChuck Attardo said: 'Elk and pronghorn like these big open structures where they can see for miles in each direction'World news | The Guardian: ““Elk and pronghorn like these big open structures where they can see for miles in each direction,” Chuck Attardo, the environmental manager for Colorado department of transportation, told CBS News.”
SupportedAttardo said pronghorn had been looking for a place to cross I-25 for decades, and for the first time in decades they now appear on video crossing to the west sideWorld news | The Guardian: ““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.””
SupportedSmaller species have been recorded using the crossing, including mule deer, coyotes, rabbits, frogs and the threatened Preble's meadow jumping mouseWorld news | The Guardian: “officials have also tracked smaller wildlife using the corridor, including mule deer, coyotes, rabbits, frogs and the threatened Preble’s meadow jumping mouse.”
SupportedThe project received $22m in federal funding and $8m from the state, though completed for about $15mWorld news | The Guardian: “The project received $22m in federal funding and $8m from the state, but officials say they were able to complete it for just $15m.”
SupportedNearly 20 wildlife crossings are under way across the United States, with the Colorado structure currently the biggestWorld news | The Guardian: “Nearly 20 wildlife crossings are under way in the US, with the structure in Colorado currently the biggest.”