A wildlife highway was built. Here’s what happened.

Wildlife crossings, including animal overpasses and wildlife underpasses, have become critical solutions for reducing wildlife-vehicle collisions and preserving ecological connectivity.

These structures enable wildlife movement across highways, ensuring safe passage for animals while preventing road accidents that endanger both wildlife and motorists.

The Effectiveness of Wildlife Crossings

A prominent success story comes from Banff National Park in Canada, where wildlife bridges and tunnels have led to an 80% reduction in animal-vehicle collisions. Similar results have been observed on Idaho’s Highway 21 wildlife overpass, where there have been zero vehicle-animal collisions since its construction.

Wildlife crossings are often accompanied by fencing to guide animals, ensuring they safely navigate highway crossings without venturing onto roadways. By mitigating roadkill incidents, these structures not only protect endangered species and local wildlife populations but also enhance human safety, reducing injury risks and vehicle damage.

There have been zero vehicle-animal collisions since Idaho’s Highway 21 wildlife overpass has been built.

How Animals Learn to Use Crossings

Wildlife crossings are typically built along natural wildlife corridors, allowing animals to safely cross roads in areas they already frequent. However, it can take up to five years for some species to fully adopt these crossings. Different species prefer different crossing types. Large mammals like deer and elk favor overpasses, while smaller animals and amphibians often utilize wildlife tunnels.

Fortunately, many animals instinctively follow established trails and use crossings as part of their migratory patterns or foraging routes, improving their effectiveness over time.

Ecological Benefits of Wildlife Crossings

Beyond road safety, wildlife overpasses and animal corridors play a vital role in habitat connectivity and biodiversity conservation. These crossings help prevent population isolation, promote genetic diversity, and allow animals to adapt to environmental changes caused by urbanization and habitat fragmentation.

Successful wildlife passage projects are not limited to North America. Similar conservation efforts have been implemented along the Ramnagar-Kotdwar Highway in Uttarakhand and the Kanha-Pench corridor in India, proving that animal crossings are a globally recognized solution for balancing infrastructure development and environmental conservation.

By integrating wildlife-friendly infrastructure, we can ensure a future where roads and nature coexist, promoting both road safety and ecosystem resilience.