New Wildlife Crossing in Colorado Would Save Lives and Money

Each fall, as temperatures drop throughout the Rockies, elk and mule deer begin their biannual migration from higher-elevation summer habitats to lower-elevation winter range. Of the many obstacles the herds face along the way, the most dangerous are the roads and highways that many animals must cross. In Colorado, about 4,000 collisions between wildlife and drivers are reported each year, injuring about 350 people, killing thousands of animals, and costing Coloradans over $75 million in property damage, medical expenses, and other costs.

Over the past five years, the state has invested in several wildlife crossings—mostly overpasses and underpasses built specifically for animals seeking to cross roads. One success story has been the State Highway 9 wildlife overpass and underpass system installed in 2016 near Kremmling, which has reduced wildlife-vehicle collisions along that stretch of road by roughly 90%. Building on that accomplishment, the Colorado Department of Transportation (CDOT) collaborated with Colorado Parks and Wildlife on the 2019 Western Slope Wildlife Prioritization Study, which identified highway segments across the western portion of the state where collisions are especially high. The report prioritized places where crossings could have the greatest impact on reducing wildlife-vehicle collisions while helping wildlife such as mule deer and elk to migrate and move safely.

Colorado Department of Transportation

One of those segments—along U.S. 550 adjacent to the Billy Creek State Wildlife Area in southwestern Colorado—is the focus of a new effort, supported by The Pew Charitable Trusts, to improve driver safety and wildlife movement in the area. The scenic highway, which bisects a critical wildlife corridor connecting the Uncompahgre Plateau with the San Juan Mountains, has grown increasingly busy, especially between the bustling cities of Durango and Montrose. CDOT projects that traffic volume will rise another 17% over the next 20 years within the project area. Mule deer and elk numbers in the surrounding landscape are already lower than what state managers have identified as necessary for healthy populations, so finding a solution to the problem in the Billy Creek segment—where approximately 50% of accidents reported to law enforcement over the past decade have involved wildlife—has become a top priority.

Pew and CDOT recently organized a group of 15 stakeholders—including representatives from local business, state transportation and wildlife agencies, conservation groups, and the federal government—for a visit to the Billy Creek project area to assess options for safe wildlife passage and build support for a solution, construction on which is tentatively scheduled to begin within the next 18 months.

Over the past few decades, the state has installed some fencing to direct animals to existing crossings around the Billy Creek wildlife area but not within it, resulting in a 2.8-mile segment where animals routinely cross the highway. Signs and large message boards warn drivers to be alert for animals on the roadway, but these have failed to meaningfully reduce collisions. Although CDOT estimates that the full menu of wildlife mitigation work and safety improvements for this project could cost as much as $30 million, it has settled for now on a $6 million plan that will include installation of 10,500 linear feet of 8-foot-tall fencing, a large wildlife underpass, and other safety improvements such as wider shoulders on the road.

Colorado Department of Transportation

Although the project received some funding from state legislation enacted in 2021, there is still a shortfall of several hundred thousand dollars, which underscores the significant challenges that states face in paying for wildlife crossings. To help close this gap, Pew is contributing financial support and expertise for the U.S. 550 project and plans to work with local partners to secure additional funding under the new federal wildlife crossing program created in the recently enacted federal Infrastructure Investment and Jobs Act. Pew is committed to working with the state and other stakeholders on a solution that makes the Billy Creek region safer for wildlife—and drivers. 

Matt Skroch is a project director and David Ellenberger is a senior associate with The Pew Charitable Trusts’ U.S. public lands and rivers conservation team.