Colorado’s giant wildlife bridge has cut I-25 animal crashes by 91% in just 10 months

A massive wildlife crossing over Interstate 25 in Colorado is already delivering the result it was built for. Ten months after opening near Larkspur, officials say collisions between vehicles and animals have dropped by 91%, beating the original estimate.

What changed on the highway

The crossing spans the six-lane stretch of I-25 near Larkspur and was opened in December. After 10 months in use, figures show crashes involving wildlife are down 91% along the corridor.

Colorado transportation officials had expected the project to cut collisions by 90%, so the early data has come in slightly better than forecast. The reduction matters to both the animals using the route and the people driving beneath it. Along the Larkspur-Monument corridor, such crashes had previously averaged about one a day.

The impact is not only being measured in collision numbers. Traffic delays have also fallen by 9%, which officials link to fewer lane closures after wildlife crashes.

Why this crossing stands out

The structure is the largest single wildlife bridge in North America. It measures 200 feet wide by 209 feet long and covers 41,800 square feet, placing it among the biggest of its kind anywhere in the world.

It is not just one bridge deck. The project also includes five wildlife underpass tunnels for smaller animals or species less likely to use the main overpass. Thousands of yards of fencing help guide animals toward those safer crossing points.

Officials say use of the system has gone beyond large animals such as bears, elk and moose. Smaller species including pronghorn antelope, northern leopard frogs and rabbits have also been using it.

One of the standout signs of progress involves pronghorn. Because they migrate, I-25 has disrupted their movement for decades. A pronghorn recorded on the overpass marked the first documented crossing of that kind in 30 years.

What could happen next

The strong early results appear to be feeding a wider push for similar projects in Colorado. Six more locations are now being scouted for wildlife overpasses, including what would be the first one designed specifically for Rocky Mountain bighorn sheep.

Named locations include the westbound lanes of I-70 at East Vail Pass between Vail and Copper Mountain, I-25 north of the New Mexico state border, US 160 east of Cortez in southwestern Colorado, Colorado 40 west of Craig, and an area near US 287 south of the Wyoming border.

For now, the headline result is simple: a crossing built for animals is also making a major difference for drivers.