Wildlife crossings are a win-win

Wildlife crossings prevent animal-vehicle collisions and reduce habitat fragmentation

Who hasn’t sadly seen an animal on the side of the road, a victim of a collision with a vehicle? Collisions between vehicles and animals are one of the leading causes of mortality for various species and are the result of the fragmentation of wildlife habitat across the United States. Due to the construction of roads and other infrastructure, animal habitat has been divided, affecting their movement and ecological connectivity. Animals depend on this connectivity in their habitats and ecosystems to search for food and water. Many need to move around in order to mate or escape danger. Wildlife crossings are a valuable tool for reducing the impact of habitat fragmentation. 

Studies indicate that wildlife crossings strengthen biodiversity and improve ecosystem resilience.  Maintaining the connectivity of wildlife habitats is one of the best ways to prevent species loss. Wildlife infrastructure is designed to help animals move, promote genetic diversity, reduce habitat fragmentation and prevent wildlife-vehicle collisions. Wildlife crossings, whether over or under roads and other infrastructure are essential to protecting biodiversity, public health, and road safety. 

A pronghorn (white, brown, and black fur with two medium-length horns on its head) stands in the middle of a grassland.
Pronghorn. Credit: California Department of Fish and Wildlife

The Danger of Roads 

Roads expose animals to vehicular traffic and increase the risks of collisions. In the United States, between one to two million vehicle collisions with large animals, including deer, mountain lions, and other species, occur each year, according to the Federal Highway Administration.  The highest number of collisions are in rural areas.

However, cities are not exempt from collisions between vehicles and animals. The 10 states with the highest risk of animal-vehicle collisions are: West Virginia, Montana, Pennsylvania, Michigan, Wisconsin, Iowa, Mississippi, South Dakota, Virginia, and Missouri, according to a recent analysis by insurer State Farm.

The Federal Highway Administration has identified 21 threatened or endangered species in the U.S. whose continued survival is threatened by road mortality. This issue impacts a multitude of animals, large and small, from mountain lions to monarch butterflies. To address the fragmentation of wildlife habitats, it is necessary to create ecological corridors, through programs for improved land planning and management. These programs also promote collaborative efforts for conservation with indigenous tribes and local communities.

A Federal Wildlife Crossing Program to Promote Wildlife Connectivity and Road Safety

In April 2023, the Biden administration unveiled the Wildlife Crossings Pilot Program, the first program promoting green connectivity and safety projects on U.S. roads. This program, established under the Bipartisan Infrastructure Act of 2021, will provide $350 million over five years to build underpasses, overpasses, and other wildlife structures.

Some funding will be directed to acquire mapping tools, carry out research and monitor the movement of animals, and help make roads safer. At least 60% of the grant funds will fund projects located in rural areas. Indigenous tribes, state transportation departments, metropolitan planning organizations (MPOs), local governments, regional transportation authorities, and federal land management agencies can all participate in this federal program. 

In 2023, 15 states introduced 21 pieces of legislation related to wildlife corridors and crossings.  For example, New Mexico passed legislation to create the Wildlife Corridors Fund with dedicated resources for the New Mexico Department of Transportation to build wildlife crossing projects for bears, cougars, deer, bighorn sheep, and other large animals. The Sandia to the Jemez Mountains project, in Albuquerque, NM, envisions multiple crossing structures to connect wildlife habitat, allow for safe wildlife migration, and improve motorist safety.

This project illustrates the importance of working with tribal partners to reconnect wildlife habitat adjacent to tribal lands. Previous legislation established the New Mexico Wildlife Corridors Action Plan to identify hotspots where wildlife corridors intersect with some of the most heavily traveled roadways.

Aerial view of the construction progress of a wildlife crossing over a highway.
The Wallis Annenberg Wildlife Crossing is under construction.

National Wildlife Federation Supports Wildlife Connectivity 

The National Wildlife Federation supports the collaborative efforts of state and federal agencies, landowners, community groups, and other NGOs to improve the ecological connectivity of wildlife habitats. In collaboration with its affiliates, the National Wildlife Federation is working on projects to reconnect, restore, enhance, and maintain the migration routes of different species such as the pronghorn, a mammal found throughout the American west. The Nature Conservancy and the National Wildlife Federation have partnered on an interactive map to study the movement of pronghorns throughout the year.

In California, the National Wildlife Federation launched the #SaveLACougars campaign to build the Wallis Annenberg Wildlife Crossing, a vegetated overpass for wildlife, which will help animals cross a 10-lane section of Highway 101. Slated for completion by early 2026, the project is located in Agoura Hills, 35 miles from Los Angeles. This is a public-private partnership project of significant scope, with oversight and core leadership from the National Park Service, the Santa Monica Mountains Conservancy/MRCA, Caltrans, and the National Wildlife Federation.

Construction of this crossing, which began in April 2022, will result in the largest wildlife crossing in the world and the first of its scale in an urban area. It aims to save a population of mountain lions from extinction by providing a connection between the small and isolated population in the Santa Monica Mountains to a larger and more genetically diverse population to the north. With a fully functioning native habitat, it is also being designed for other wildlife to utilize.

A mountain lion (tan and white fur with a few black patches) can be seen trotting through a desert area at night.
California’s beloved mountain lion, P-22. Credit: Miguel Ordeñana

The iconic mountain lion P-22, who made a miraculous journey across two major freeways to find a home, and roamed the Hollywood hills for over a decade, served as the poster-cat for the #SaveLACougars campaign. Sadly, in December of 2022, P-22 was hit by a car and had to be euthanized due to his injuries and other health issues. Yet his legacy lives on, as P-22 helped raise awareness in the U.S. and across the world about the dangers of highways to big cats and other species, and the devastating impacts on habitat fragmentation on all wildlife.

You can see real-time footage of the progress of the construction of the Wallis Annenberg Wildlife Crossing here.

Private lands, including working lands such as farms and ranches, also provide significant wildlife habitat. U.S. Department of Agriculture conservation programs often support this. In the 2018 Farm Bill, which funds and directs USDA programs, significant progress was made by directing 10% of the largest working lands conservation program toward practices that benefit wildlife. In the next Farm Bill, NWF is working to expand these practices to include wildlife crossings and related activities.

Learn more about the National Wildlife Federation’s priorities here.