Colorado wildlife overpass cuts animal-vehicle collisions by 91%
A wildlife overpass built across Interstate 25 in Colorado has reduced collisions between animals and vehicles by 91% in the ten months since it opened, according to a new report. Elk, bears, pronghorn and many smaller species are using it.
Officials in the US state of Colorado say a wildlife overpass spanning Interstate 25 has cut collisions between animals and vehicles by 91% in the ten months since it opened, according to a newly released report. Such crossings are meant to protect wildlife habitat and reduce crashes that can injure or kill both people and animals.
Before the structure was built, this stretch of highway averaged one wildlife-vehicle crash a day, the Colorado Department of Transportation said. The overpass sits between the state's two biggest cities, Denver and Colorado Springs. It crosses six lanes of traffic and links 39,000 acres of habitat on either side of the road. The grass-covered bridge is 200 feet wide and 209 feet long, with gently sloped approaches to make crossing easier for animals.
Who is using it
Officials have tracked herds of elk, bears, pronghorn and northern leopard frogs crossing the bridge. Smaller animals, including mule deer, coyotes, rabbits, frogs and the threatened Preble's meadow jumping mouse, have also been recorded.
Brandon Marette, a wildlife biologist with Colorado Parks and Wildlife, said one of the most heartening moments was a photo of a mother elk leading her calf under the interstate. Chuck Attardo, the transportation department's environmental manager, explained that elk and pronghorn favour large, open structures with long sightlines. Underpasses and tunnels often fail for big animals because they restrict movement and do not accommodate antlers. Pronghorn that spent decades seeking a way across I-25 have now reached the western side for the first time in decades, he said.
Cost and next steps
The project received $22m in federal funding and $8m from the state, but was finished for $15m. Research indicates overpasses nearly eliminate such accidents and often pay for themselves by preventing costly crashes. Nearly 20 wildlife crossings are under way across the US, and Colorado's is currently the largest. The department says it hopes to build more across the state.
