SAN FRANCISCO (KRON) -- At least 750 mountain lions in California die by vehicle collisions each year, according to a report released Tuesday by the University of California Davis Road Ecology Center.
The study called the annual death toll, which reflects 18% of the state’s mountain lion population, a “minimum” since there is no requirement to report roadkilled wildlife. The data comes from reports to the California Roadkill Observation System and from the California Highway Patrol, and only covers state highways and major paved roads.
“Like most species at the top of the food web, mountain lions are especially vulnerable to (wildlife-vehicle collisions) because they have large home ranges and can move many miles per day across the landscape, thus encountering numerous roads cutting across their paths,” the report states.
The highest rates of deadly mountain lion collisions around the Bay Area include Interstate 280 on the San Francisco Peninsula and Highway 101 in Marin County.
(Graphic: UC Davis Road Ecology Center)
What can be done to curb roadkill rates? The study points to erecting wildlife fencing and using it with existing passage structures.
“Caltrans manages at least 8,500 and likely many more existing structures that most wildlife species can already use to cross under state highways,” the report states. “What’s missing in almost all cases is barrier fencing to keep them from entering the highway and dying and instead finding the crossing.”
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The study’s authors describe wildlife fencing as a metal mesh stretched between posts that is ideally at least 8 feet tall with outriggers on top, ensuring small animals cannot squeeze through and climbers or high-jumpers can be stopped from going over.
“In many areas, fencing costs less than the crashes that occur without the fencing, meaning it costs less to put in fencing in hotspots than to just not do it,” the study stated.
The full 2026 California Roadkill Hotspots Report is available to view on the UC Davis website.
