We’ve all seen roadkill. Some have been unlucky enough to hit a deer or other large animal. These collisions with wildlife are bad news for all species, including our own.
In the U.S. there are 1-2 million wildlife-vehicle collisions with large animals every year, resulting in 26,000 human injuries, 200 human deaths and $8 billion in property damage.
Then there’s the damage to wildlife. A study found that more than 350 million vertebrate animals, big and small, are killed by vehicles in the U.S. every year.
Beyond the scenes of death along our roads and the hits that animal populations are taking from vehicles, there’s another problem. America’s freeways and highways cut through wildlife habitats, dividing landscapes, making them too small for animals that need to move in order to graze, hunt, mate and migrate.
Mountain lions, panthers, turtles, elk, deer, black bears, newts and more face a lose-lose decision: Cross a busy, dangerous road or get penned into a small habitat that doesn’t work for their long-term survival.
Example: A mountain lion living in Los Angeles
The people of Los Angeles still mourn the death of a mountain lion named P22. He won their hearts by somehow crossing multiple busy freeways in Los Angeles before settling into Griffith Park, where he lived for 10 years but never found his sought-after mate. The story of P22 is captivating, and the details are unique, but the larger story of animals needing to cross busy roads is quite common.
A staggering drop in animal populations
Vehicle-wildlife collisions are set against a troubling backdrop of rapidly declining wildlife populations.
Researchers at the World Wildlife Fund and the Zoological Society of London have documented a staggering decline in wildlife populations. They conducted a long-term study of 5,495 mammals, reptiles, amphibians and birds in North America and found a 73% decline in animal populations from 1970 to 2020.
Moreover, state wildlife agencies have identified more than 12,000 species in need of additional conservation efforts to prevent them from sliding toward extinction.
A simple, obvious but not inexpensive solution
Wildlife bridges over busy roads and tunnels and culverts under them prevent vehicle-wildlife collisions. Fencing can force animals to cross in the designated locations.
How effective are these wildlife crossings, and do animals really use them? We’re starting to get real inputs and data because more than 1,000 wildlife crossings are in operation in the U.S.
It’s looking very promising. When placed in areas of known wildlife movement, wildlife crossings with additional elements such as fencing have reduced wildlife-vehicle collisions by up to 97%.
Some fun examples… There’s a bridge in Utah over Interstate 80, and animals adapted to it more quickly than experts expected. In Arizona, as of 2020, one wildlife overpass was used more than 6,000 times by wildlife, including bighorn sheep, foxes, bobcats, deer and coyotes.
In terms of building these things, one roadblock is the cost, but even on that front there’s promising news. A Washington State University study of wildlife crossings determined that each overpass saved between $235,000 and $443,000 per year due to reduced collisions.
There’s money, and it’s in demand
In 2020, Congress passed the bipartisan infrastructure deal. The law included funding for roads and included $350 million for wildlife crossings. The money is dispersed by the U.S. DOT in a grants program. In the current fiscal year, projects in Alaska, Arizona, Florida, Georgia, Idaho, Massachusetts, Maryland, Maine, Michigan, Missouri, Montana, New Mexico, North Carolina, Nevada, New York and Oregon received funding.
States are chipping in with their own funds. California, Colorado, Massachusetts, New Mexico, Oregon, Utah, Wyoming and perhaps more have provided funds for wildlife crossings — money that can complement federal funds or enable a state to fly solo on a project, if needed.
So let’s keep going
Wildlife crossings are an important, effective tool to save wild animals. We’ll see less roadkill, and fewer drivers will be hospitalized from a deer running into their path. Let’s keep building.
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Authors
Started on staff: 1991
B.A., Wartburg College
Steve directs Environment America’s efforts to protect our public lands and waters and the species that depend on them. He led our successful campaign to win full and permanent funding for our nation’s best conservation and recreation program, the Land and Water Conservation Fund. He previously oversaw U.S. PIRG’s public health campaigns. Steve lives in Sacramento, California, with his family, where he enjoys biking and exploring Northern California.
