Wildlife Crossings Along U.S. Roads Can Help Animals and Habitat Adapt to Climate Change

Pew joins experts in calling for policies to address transportation infrastructure and ecosystem resilience

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Wildlife Crossings Along U.S. Roads Can Help Animals and Habitat Adapt to Climate Change
Sunrise At Convict Lake Through Smoke From The Creek Fire.
Smoke from 2020’s Creek Fire in California descends on Conflict Lake. Climate change-related events, such as wildfires, are forcing animals to migrate and travel in different patterns than before.
Jim Brown EyeEm

Editor’s note: The headline was updated on Feb. 16, 2023, to clarify the relationship between wildlife crossings and climate adaptation.

Across the U.S., the success of wildlife crossings—bridges, underpasses, and culverts designed to help animals avoid vehicle traffic—is drawing a surge of interest from policymakers seeking to reduce wildlife-vehicle collisions and protect animals.

For example, a crossing along State Highway 9 in Colorado reduced such collisions by 90% from 2015 to 2020. And in Oregon along U.S. 97 near Lava Butte, collisions decreased by roughly 85% during a 2015-17 monitoring period. Wildlife-vehicle collisions on the nation’s roads claim the lives of millions of animals—and kill or injure tens of thousands of people—each year.

Recent advances in research and technology have helped agencies precisely site wildlife crossings in the places they’ll do the most good, for both motorists and animals. Now, as many species’ ranges and habitat shift because of climate change, experts say that wildlife crossing structures can provide the added value of helping animals adapt. 

Two elk stand by the road as traffic moves over a large underground crossing structure that allows animals to pass under US 285 at this point on the 2 mile long Safety Treatment Corridor along US 285 just South of Buena Vista, CO. on Tuesday, September 17, 2019
Wildlife crossings and directional fencing, such as this project along U.S. 285 just south of Buena Vista, Colorado, save lives and money by decreasing wildlife-vehicle collisions. Despite these benefits, most crossing projects do not currently take climate change into account.
Matthew Staver For The Washington Post via Getty Images

To broaden awareness of this emerging research, in November Pew convened leading wildlife and climate experts from throughout the country to analyze and address how wildlife crossings can address climate change and contribute to resilient ecosystems. The experts, who included researchers and policy professionals from the public and private sectors, co-authored a consensus statement and recommendations for including wildlife crossings in local, state, and federal climate adaptation strategies. 

The group agreed that “(w)arming temperatures, shifting precipitation patterns, and more frequent and severe climate-exacerbated disasters are transforming habitats, prompting wildlife to shift their ranges, and compromising infrastructure, among other impacts.” They added that wildlife crossings offer the potential to “enhance the resilience and adaptive capacity of ecosystems and infrastructure in the face of changing climatic conditions.” 

The ability for animals to migrate and move in response to changing conditions or extreme weather is fundamental to ecosystem resilience, helping to ensure not only one species’ survival but the broader balance of predators and prey, and healthy habitat. Throughout the country, roads and highways often bisect—and in some cases fully block—those natural routes; wildlife crossings can maintain or restore key ecological connections while lowering the risk of road accidents. In many places, for example, governments are replacing or upgrading culverts to accommodate an increase in flooding. In doing so, they have an opportunity to factor wildlife passage into the design, making both the infrastructure and ecology of the surrounding area more resilient. 

A bird’s-eye view shows a rendering of the Snoqualmie Pass wildlife overpass on I-90 in Washington, one of 27 structures that, when completed in 2029, will connect terrestrial and aquatic habitats along one of the busiest corridors in the Pacific Northwest.
A wildlife crossing spans Interstate 90 in Snoqualmie Pass, Washington. A network of bridges and culverts in the North Cascades is substantively improving ecological connectivity and helping make the region more resilient to climate change.
Washington State Department of Transportation Flickr

The consensus statement offers federal, Tribal, and state decision-makers a suite of options and recommendations for how to best incorporate wildlife crossings into transportation planning. For example, the experts recommend that state and federal agencies invest in and support modern and innovative wildlife crossing plans and designs while also applying Indigenous knowledge and the best available science.   

The recommendations include guidance for prioritizing crossing investments in landscapes that have a high degree of resilience in the face of climate change, such as East Vail Pass in Colorado, and establishing permanent federal funding mechanisms that support climate-informed wildlife crossings.  

Mule deer graze along a stretch of Highway 20 along Malheur River Canyon in Eastern Oregon
Mule deer browse in the brush just off Highway 20 in eastern Oregon, a hot spot for wildlife-vehicle collisions. Mule deer populations in this area have been steadily declining. To help reverse that trend, the Burns Paiute Tribe is working with state and federal officials to construct wildlife crossings.
Jessica Sherry Alita Films

The consensus statement and recommendations come at an important time as federal, state, and Tribal governments increasingly embrace wildlife crossings while grappling with how to best respond to climate change. Transportation infrastructure designed with ecosystem and climate resilience in mind benefits both the built and natural environments. Decision-makers now have more of the building blocks they need to design policy and funding streams to help the country weather the changes that lie ahead. 

Matt Skroch is a project director and Leslie Duncan is a senior officer with The Pew Charitable Trusts’ U.S. public lands and rivers conservation project.

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A truck emerges from the Trappers Point wildlife overpass on US 191 near Pinedale, Wyoming.
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A line of brown female elk walk from left rear to right front along a deep path in snow with snow-flecked fir trees, blue sky, and puffy clouds in the background.
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