American Civil Liberties Union

The ACLU’s Nationwide Public Records Request

In July 2012, American Civil Liberties Union affiliates in 38 states and Washington, D.C. sent 587 requests to local police departments and state agencies that demand information on how they use automatic license plate readers (ALPR) to track and record Americans’ movements.

On the same day, the ACLU and the ACLU of Massachusetts filed federal Freedom of Information Act requests with the Departments of Justice, Homeland Security, and Transportation to learn how the federal government funds ALPR expansion nationwide and uses the technology itself.

Background on ALPRs

ALPRs are cameras mounted on stationary objects (telephone poles, the underside of bridges, etc.) or on patrol cars. The cameras snap a photograph of every license plate that passes them by – capturing information on up to thousands of cars per minute. The devices convert each license plate number into machine-readable text and check them against agency-selected databases or manually-entered license plate numbers, providing an alert to a patrol officer whenever a match or “hit” appears.

When the ALPR system captures an image of a car, it also meta-tags each file with the GPS location and the time and date showing where and when the photograph was snapped. And often, the photograph—not just the plate number—is also stored. The system gathers this information on every car it comes in contact with, not simply those to which some flag or “hit” was attached.

What’s The Problem?

When used in a narrow and carefully regulated way, ALPRs can help police recover stolen cars and arrest people with outstanding warrants.

Unfortunately, law enforcement agencies are increasingly moving towards a “keep everything, share widely” formula concerning ALPR data. The biggest problem with ALPR systems is the creation of databases with location information on every motorist who encounters the system, not just those whom the government suspects of criminal activity. Police departments nationwide are using ALPR to quietly accumulate millions of plate records, storing them in backend databases. While we don’t know the full extent of this problem, we know that responsible deletion of data is the exception, not the norm. Only two states have passed legislation barring the retention of “non-hit” plate data for extended periods. On the other hand, we know for certain that some departments are eagerly engaging in this surreptitious data collection.

As license plate location data accumulates, the system ceases to be simply a mechanism enabling efficient police work and becomes a warrantless tracking tool, enabling retroactive surveillance of millions of people.

Location information can reveal deeply sensitive and intimate details of our lives. As the International Association of Chiefs of Police has put it, “mobile LPR cameras may collect the license plate numbers of vehicles parked at locations that, even though public, might be considered sensitive, such as doctor’ offices, clinics, churches, and addiction counseling meetings, among others.”

In a case in which law enforcement agents attached a GPS device to a car and tracked it for 28 days, Justice Alito explained that “society’s expectation has been that law enforcement agents and others would not—and indeed, in the main, simply could not—secretly monitor and catalogue every single movement of an individual’s car for a very long period.” ALPR systems pose the same risk, except they involve tracking all of us rather than specifically targeted individuals.