Colorado wildlife overpass cuts crashes by 91%

A bridge built for wildlife over Interstate-25 between Denver and Colorado Springs has cut collisions between vehicles and animals by 91% in the 10 months since it was completed, according to a newly released report. The Guardian

The stretch averaged one wildlife-vehicle crash a day before the system was built, according to the Colorado Department of Transportation. The crossing is located near Castle Rock, where drivers have hit two animals since it opened, Colorado Sun reported.

The bridge spans six lanes of traffic. It measures 200 feet wide and 209 feet long and links about 39,000 acres of habitat on either side of the highway. The structure is designed to let animals pass over the road rather than through traffic, keeping a connected landscape for herds that move across the area.

It does not stand alone. Miles of 8-foot-tall fencing run along the corridor to keep animals off the roadway and direct them toward safe passage. Five large underpasses were built as part of the same system, giving smaller or more wary species other routes beneath the interstate.

The project received $22 million in federal funding and $8 million from the state. It is described as the biggest wildlife crossing in the United States, with nearly 20 similar crossings now underway nationally. It has also been described as the largest animal-crossing overpass in North America. Smithsonian Magazine

Colorado has tested this approach before. Crossings along state highway CO 9 reduced wildlife crashes by 92%, according to state transportation documents, and wildlife experts consider that system the gold standard in the country. That earlier count was based on collisions reported to law enforcement, and a state review found 17 different species had successfully used those structures.