Home / Environment / Colorado's Overpass: A Bridge for Wildlife
Colorado's Overpass: A Bridge for Wildlife
23 Oct
Summary
- Wildlife collisions fell 85% annually after mitigation infrastructure.
- Largest wildlife overpass in North America spans six lanes.
- Elk, pronghorn, rabbits, and frogs use new wildlife crossings.
In Colorado, a network of wildlife crossings is transforming Interstate 25 into a safer route for animals and drivers. Previously, this vital transport artery acted as a dangerous barrier, disrupting animal migrations and leading to frequent collisions. Agencies initiated a comprehensive mitigation program in 1996, incorporating extensive fencing and underpasses.
The program's centerpiece, a $15 million wildlife overpass near Monument that opened in December 2025, is North America's largest. This structure spans six lanes of traffic, offering a safe passage over the highway. These combined efforts have yielded remarkable results.
Data from 2022 to 2024 revealed an 85% annual reduction in wildlife-vehicle collisions along the 18-mile corridor. In the most recent year studied, collisions dropped by 91%. This significant decline highlights the effectiveness of infrastructure designed to accommodate animal movement.
Trail cameras and surveys confirm a diverse range of wildlife is using the crossings. Elk have been documented on the overpass, and pronghorn are regaining safe passage. Smaller animals, including frogs and rabbits, are also benefiting. Efforts are underway to enhance vegetation on the overpass to further attract wildlife.
Colorado plans to expand this success, developing six additional crossing systems. These projects, though requiring substantial investment, promise to reduce economic costs associated with accidents and improve overall road safety. The state's initiative offers a model for integrating conservation infrastructure with traditional road safety measures.
