San Francisco—Electronic Frontier Foundation (EFF) and the American Civil Liberties Union Foundation of Southern California (ACLU SoCal) have reached an agreement with Los Angeles law enforcement agencies under which the police and sheriff’s departments will turn over license plate data they indiscriminately collected on millions of law-abiding drivers in Southern California.

The data, which has been deidentified to protect drivers’ privacy, will allow EFF and ACLU SoCal to learn how the agencies are using automated license plate reader (ALPR) systems throughout the city and county of Los Angeles and educate the public on the privacy risks posed by this intrusive technology. A weeks’ worth of data, composed of nearly 3 million data points, will be examined.

ALPR systems include cameras mounted on police cars and at fixed locations that scan every license plate that comes into view—up to 1,800 plates per minute. They record data on each plate, including the precise time, date, and place it was encountered. The two Los Angeles agencies scan about 3 million plates every week and store the data for years at a time. Using this data, police can learn where we were in the past and infer intimate details of our daily lives such as where we work and live, who our friends are, what religious or political activities we attend, and much more.

Millions of vehicles across the country have had their license plates scanned by police—and more than 99% of them weren’t associated with any crimes. Yet law enforcement agencies often share ALPR information with their counterparts in other jurisdictions, as well as with border agents,  airport security, and university police.

EFF and ACLU SoCal reached the agreement with the Los Angeles Police and Sheriff’s Departments after winning a precedent-setting decision in 2017 from the California Supreme Court in our public records lawsuit against the two agencies. The court held that the data are not investigative records under the California Public Records Act that law enforcement can keep secret.

“After six years of litigation, EFF and ACLU SoCal are finally getting access to millions of ALPR scans that will shed light on how the technology is being used, where it’s being used, and how it affects people’s privacy,” said EFF Surveillance Litigation Director Jennifer Lynch. “We persevered and won a tough battle against law enforcement agencies that wanted to keep this information from the public. We have a right to information about how government agencies are using high-tech systems to track our locations, surveil our neighborhoods, and collect private information without our knowledge and consent.”

The California Supreme Court ruling has significance beyond the ALPR case. It set a groundbreaking precedent that mass, indiscriminate data collection by the police can’t be withheld just because the information may contain some data related to criminal investigations.

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