Wildlife-Vehicle Collisions Cost California $1B Over 5 Years, Involved At Least 400 Species

Over the past five years, vehicle collisions with wildlife have cost California an estimated $1 billion. Over 400 species of animals were involved, including mammals, birds, amphibians, and reptiles.

The findings come from a report by the Road Ecology Center at the University of California that named Interstate 280 between San Bruno and Cupertino as California's deadliest highway, The Associated Press reported. Over 44,000 California Highway Patrol traffic incidents involving animals between 2009 and 2020 were used to make the report. There are also over 65,000 reports from members of the public via the California Roadkill Observation System phone app.

Roughly 15,000 miles of state roadways were mapped by the center to identify where collisions with wildlife are most likely to occur.

The report identified the top 20 "hot spots," five of which are on I-280. Researchers estimated those five areas cost the state $5.8 million annually, about $178,400 per mile per year, in cleanup and damages.

The estimated $1 billion costs comes from highway patrol reports and crash data from the U.S. Department of Transportation. When combining the accidents reported to insurance companies and not to police, though, estimates increased to $2 billion for 2016 through 2020, the report stated.

Of all the animal species involved, mountain lions and blacks bear are the most vulnerable to collisions. Amid their shrinking habitat, they often cross highways. The study reported more than 557 blacks bears and 300 mountain lions were killed on roads between 2016 and 2020.

For more reporting from the Associated Press, see below.

Animals, Car, Collisions, California
This image provided by the California Highway Patrol, West Valley Division, shows a mountain lion found dead along Interstate 101 in Calabasas, Calif. Tens of thousands of mountain lions, bears, bighorn sheep, squirrels, birds and lizards have met their fate in collisions with vehicles across California in a study released by the Road Ecology Center at the University of California, Davis. California Highway Patrol via AP

One of the largest rates of roadkill reported for any wildlife species in the world occurs each year in Santa Clara County, south of San Francisco, the report said. Pacific newts cross Alma Bridge Road while migrating from a forest to Lexington Reservoir, then return after reproducing. Along the way, up to 5,000 newts are killed each winter and spring by vehicles, the research showed.

"These findings illustrate the tip of the iceberg of ecological and economic impacts that wildlife-vehicle collisions cause for California," said Fraser Shilling, the study's lead author. "We need the Legislature to step in and help the good folks in transportation to fence the conflict hot spots and build many more wildlife crossings."

Dedicated bridges for animals to cross highways are the best way to alleviate the problem, researchers concluded. Alameda County, east of San Francisco, is exploring potential sites for such spans. In Southern California, groundbreaking is expected next year for what would be one of the world's largest wildlife crossings, over U.S. 101 northwest of Los Angeles.

"The advantages to building more wildlife crossings couldn't be more obvious. They help make roads safer for drivers and passengers while giving animals a way to roam and thrive," said Tiffany Yap, senior scientist and wildlife connectivity advocate at the Center for Biological Diversity.

Black Bears, California, Collisions
A black bear cub sits in a tree. Black bears are one of the most vulnerable among the 400 species of animals involved in collisions with vehicles in California. The collisions have costed California an estimated $1 billion in the past five years. Raymond Gehman/Corbis via Getty Images