A new study published in PNAS Nexus from researchers at the University of California, Davis, has revealed that individuals subject to California’s extreme risk protection order (ERPO) were significantly less likely to be arrested — including for violent and firearm-related offenses — both during the order and in the months after it expired.
ERPOs are court-issued orders that temporarily restrict firearm access for individuals deemed to pose a significant danger of harming themselves or others. They are designed as a tool to address gun violence.
Compared to arrest rates in the six months before an ERPO was issued, while the orders were in effect, overall arrests dropped by 55%. Violent crime arrests fell by 71%, firearm-related arrests by 76%, and firearm violence arrests by 80%.
Even more striking, in the six months after the order expired, overall arrests remained 63% lower, violent crime arrests were down 75%, firearm-related arrests were 70% lower, and firearm violence arrests were 63% lower.
“ERPOs are often discussed as a suicide prevention tool, but our findings suggest they also play a meaningful role in reducing interpersonal violence,” said lead author Veronica Pear, an assistant professor and epidemiologist at UC Davis.
The study, which focused on Yolo County and the city of Davis, adds to limited evidence on whether ERPOs reduce crime and violence. The findings suggest the laws may interrupt criminal behavior, including violence, and produce sustained benefits beyond the intervention period.
America’s ongoing firearm violence epidemic resulted in 43,593 deaths in 2024. In 2025, about 40,000 people have been shot, excluding suicides — more than 110 people a day nationwide.
ERPO laws are now in place in 22 states, Washington, D.C., and the US Virgin Islands, and remain a major policy focus nationwide.