Wild animals are finding safer passage across a busy Colorado freeway thanks to a wildlife mitigation system — including fencing, underpasses, and North America’s largest wildlife overpass — that has helped reduce wildlife-vehicle collisions by 91%, according to Smithsonian Magazine.
Spanning 18 miles between Castle Rock and Monument, the system combines eight-foot-tall fencing with five underpasses and a 209-by-200-foot overpass. The overpass completed the project in December 2025, and officials reported that just two animals were struck by vehicles in the roughly ten months that followed.
Designed primarily to help elk and pronghorn safely cross an interstate traveled by more than 100,000 vehicles daily, the overpass has also been used by bears, deer, coyotes, rabbits, and frogs.
To help smaller animals cross without being exposed to predators, wildlife officials arranged logs along the overpass to create a sheltered route. The added cover is intended to protect species such as the threatened Preble’s meadow jumping mouse from coyotes, foxes, and hawks.
Efforts to grow vegetation to encourage animals to use the overpass have been slowed by this year’s drought, but future plant growth could make the crossing even more effective.
Colorado officials are also planning six additional wildlife crossing systems, as a recently passed state law expands funding for projects that help animals cross roads safely.
Lady Freethinker is grateful to everyone working to protect wildlife along Colorado’s roads and hopes their efforts inspire the construction of similar crossings for animals around the world.
