By: Peter Bibring and Jennifer Lynch
In a ruling that will harm the public’s ability to engage in an informed debate over the use of automated license plate readers (ALPR) in California, a judge late last week rejected EFF and the ACLU Foundation of Southern California’s argument that the Los Angeles Police Department and Los Angeles County Sheriff’s Department should hand over a week's worth of license plate data.
But the ruling isn’t what you might think—the court didn’t decide that location information is too private and too sensitive to release to the public. Instead, the court held that the ALPR data qualifies as the kind of investigative record police can keep secret and that the harm to law enforcement investigations from disclosing data outweighs the value to the public of seeing what data police collect on them.  If you think that sounds like a big, blank check to California police to build surveillance programs outside of public scrutiny, you’re right.
What We Know about ALPRs
LAPD and LASD’s ALPR cameras are mounted on squad cars and at fixed locations around the region. They automatically record not just the license plate of every vehicle that passes, but also its time, date and location and a photograph of the car when its plate was scanned. These systems can collect data on hundreds of plates per minute and create a detailed picture of the comings and goings of everyday people.
LAPD and LASD admitted at our court hearing that they collect—combined and on average—data on nearly 3 million cars per week. This amounts to nearly half of all vehicles registered in Los Angeles. The agencies store this data for anywhere from two to five years—whether or not the plates are ever linked to a crime—and share it with nearly 30 other law enforcement agencies around the region. Because the the data includes location information, it can become very revealing over time. It can show not only where you live and work, but your political and religious beliefs, your social and sexual habits, your visits to the doctor, and your associations with others.
The ACLU has reported that only about .2% of plates scanned by ALPR systems are ever linked to any wrongdoing, and only 3% of those (3 out of every 50,000 plates scanned) are linked to crimes other than licensing or emissions violations. But the LA agencies claimed in court that every one of these records was part of a vast investigation into stolen vehicles and other crimes and could not be disclosed to the public—even with redactions in place to protect drivers’ privacy. Unfortunately, the court agreed.
Everyone is Under Investigation, Always.
ALPR Camera Mounted on Squad CarWe think drivers would be surprised to learn that they are under investigation every time they drive in public. Most people think of an “investigation” as being targeted in some way—looking for the culprit in a specific crime and focusing on a particular person or group of people police have reason to think might be involved in criminal activity. An “investigation” doesn’t usually involve collecting facts on every single person police can contact.  In fact, the Fourth Amendment was added to the U.S. Constitution exactly to prevent law enforcement from conducting mass, suspicionless investigations under “general warrants” that target no specific person or place and never expire.
ALPR scans look a lot like these general warrants. Even though LAPD and LASD argued that the records were collected as part of investigations into stolen vehicles and other crimes, the plate scans are not triggered by any level of suspicion at all. Instead, ALPR cameras scan every plate that comes into view—automatically—whether the squad car is in the police parking lot or driving past a mosque. The officer in the squad car does nothing to focus the camera or program it to take a picture of one vehicle rather than another. At the instant any plate is photographed, not even the computer system itself—let alone the officer—has any reason to think the plate is linked to a crime. And the cameras are on and collecting data during the officer’s entire shift. If this is really a police investigation, then it’s exactly the type of investigation the Fourth Amendment was designed to prevent.
The court appears to disregard these facts, however. It held that because cops may pick specific neighborhoods to drive in or routes to follow with their camera-equipped cars, ALPR data generated by mobile cameras is targeted and “is not the indiscriminate recording of license plates.” Not only is this a fundamental misunderstanding of how these systems operate, it is an important error for our case; the court later suggests that if ALPR data were indiscriminate, “it might not constitute a record of investigation” and thus would not be exempt from disclosure under the California Public Records Act (CPRA).
Is Secrecy Better than Transparency?
Perhaps more troubling is the court’s second reason for withholding records—its holding that the threat to ongoing investigations from revealing the data “substantially outweighed” the public interest in seeing the information the police collect.
There’s little in the record to suggest that historical ALPR data is really useful for ongoing investigations. ALPRs are used mostly for alerting police in real-time when a car linked with unlawful activity (from licensing violations to serious crime) is nearby, so the officer can write a ticket, make an arrest, or recover the car. But that activity wouldn’t be hindered by providing the public with a list of the vehicles ALPRs had scanned. The two agencies provided only a couple of anecdotal examples where they asserted that consulting the historical ALPR database proved useful to an investigation. And they provided no real evidence or explanation on how making the data public could threaten ongoing investigations—especially given that they could redact any data associated with plates on a "hot list." Presumably, criminals already know that their cars have license plates and might be spotted by police.
More importantly, if this data does reveal patterns of surveillance, that is even more reason for the cops to be required to release it. We sought this data in the first place because we believe that disclosure of a limited amount of data the cops collect through ALPR systems—data from one week in 2012—is necessary to inform the public debate about the appropriate use of and limitations on these systems. We think seeing the actual data points is the best way to understand exactly how and where cops use these cameras. For example, without the raw data, we can’t learn whether cops are scanning more plates in Compton than in Beverly Hills or scanning specific vehicles’ plates multiple times. Also, seeing those millions of data points plotted on a map of the greater LA area makes the sheer volume and intrusiveness of the surveillance apparent in a way that is more powerful than merely reciting the number of ALPR cameras in use or plate scans collected each week.
As the court noted, the CPRA “was intended to safeguard the accountability of government to the public . . . and makes public access to government records a fundamental right of citizenship.” This access provides a necessary check against government secrecy and the arbitrary exercise of official power and—because of the power the police wield—is no more necessary than when the records concern police conduct. Californians should have access to this data because it could reveal patterns of policing. Without the data, the public cannot fully determine whether the police are using ALPR systems appropriately—or in a manner that violates civil rights.
The court’s ruling in the case is dangerous because it means that the police can institute broad, suspicionless and indiscriminate surveillance practices—practices that scoop up sensitive data on millions of law-abiding citizens—without any possibility of public review. Under the court’s ruling, you can’t request even the ALPR data police have collected about your own car. The CPRA was intended to ensure government accountability; with a ruling like this, the public’s ability to be a check against arbitrary and discriminatory police practices is severely weakened.
Peter Bibring is senior staff attorney at the ACLU of Southern California, and Jennifer Lynch is senior staff attorney at the Electronic Frontier Foundation.

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