California Attorney General Rob Bonta has issued a legal interpretation and guidance for law enforcement agencies around the state that confirms what privacy advocates have been saying for years: It is against the law for police to share data collected from license plate readers with out-of-state or federal agencies. This is an important victory for immigrants, abortion seekers, protesters, and everyone else who drives a car, as our movements expose intimate details about where we’ve been and what we’ve been doing.

Automated license plate readers (ALPRs) are cameras that capture the movements of vehicles and upload the location of the vehicles to a searchable, shareable database. Law enforcement often installs these devices on fixed locations, such as street lights, as well as on patrol vehicles that are used to canvass neighborhoods. It is a mass surveillance technology that collects data on everyone. In fact, EFF research has found that more than 99.9% of the data collected is unconnected to any crime or other public safety interest.

The California State legislature passed SB 34 in 2015 to require basic safeguards for the use of ALPRs. These include a prohibition on California agencies from sharing data with non-California agencies. They also include the publication of a usage policy that is consistent with civil liberties and privacy.

As EFF and other groups such as the ACLU of California, MuckRock News, and the Center for Human Rights and Privacy have demonstrated over and over again through public records requests, many California agencies have either ignored or defied these policies, putting Californians at risk. In some cases, agencies have shared data with hundreds of out-of-state agencies (including in states with abortion restrictions) and with federal agencies (such as U.S. Customs & Border Protection and U.S. Immigration & Customs Enforcement). This surveillance is especially threatening to vulnerable populations, such as migrants and abortion seekers, whose rights are protected in California but not recognized by other states or the federal government.

In 2019, EFF successfully lobbied the legislature to order the California State Auditor to investigate the use of ALPR. The resulting report came out in 2020, with damning findings that agencies were flagrantly violating the law. While state lawmakers have introduced legislation to address the findings, so far no bill has passed. In the absence of new legislative action, Attorney General Bonta's new memo, grounded in SB 34, serves as canon for how local agencies should treat ALPR data.

The bulletin comes after EFF and the California ACLU affiliates sued the Marin County Sheriff in 2021, because his agency was violating SB 34 by sending its ALPR data to federal agencies including ICE and CBP. The case was favorably settled.

Attorney General Bonta’s guidance also follows new advocacy by these groups earlier this year. Along with the ACLU of Northern California and the ACLU of Southern California, EFF released public records from more than 70 law enforcement agencies in California that showed they were sharing data with states that have enacted abortion restrictions. We sent letters to each of the agencies demanding they end the sharing immediately. Dozens complied. Some disagreed with our determination, but nonetheless agreed to pursue new policies to protect abortion access.

Now California’s top law enforcement officer has determined that out-of-state data sharing is illegal and has drafted a model policy. Every agency in California must follow Attorney General Bonta's guidance, review their data sharing, and cut off every out-of-state and federal agency.

Or better yet, they could end their ALPR program altogether.