Are License Plate Readers Being Used to Track Innocent People?

By Karina Ioffee

Police departments across the country are using license plate readers to collect massive amounts of data about our driving patterns, information that is in most cases stored indefinitely, according to a new American Civil Liberties Union report released Wednesday.

Over the past several years, license plate readers have been implemented by many law enforcement agencies, who credit the relatively-cheap technology with retrieving stolen vehicles, apprehending wanted criminals and finding kidnapped children.

But the ACLU says most police departments don’t have guidelines in place to prevent the information collected by license readers from being used to track movements of innocent people, including specific religions, ethnic groups, political activists or anyone else considered “a person of interest.” 

“We know agencies are collecting thousands, even millions of records about individuals, towns in Northern California that have populations of 10,000 or 20,000, have databases full of millions of records from license plates,” attorney Chris Conley told NBC Wednesday.

Many North Bay cities have license plate readers, which are typically mounted on street posts or police cars. But according to the ACLU, only a small percentage of license plate “reads” turn into actual hits and even less result in an arrest.

To learn about how license readers work and why privacy advocates are concerned, watch this brief slideshow by Newshound

In one example, the ACLU found that for every 1 million plates scanned in Maryland, 2,000 came back as hits (typically people with expired registrations or whose cars had not passed a smog test.) Of those, only 47 cars ended up being linked to criminals.

The collected data is not stored by agencies, but aggregated by off-site servers. One, called the National Vehicle Location Service, has more than 800 million license plate numbers, information that can be collated over time to figure out patterns about where people go and how often.

The ACLU says license readers can be used to fight crime, but wants stricter guidelines about how long the information is kept. In most cases, data should not be stored longer than a month, they say.

The Novato Police Department began using license plate readers about a year ago and credits them for helping track down one to two stolen cars each month. The agency does not use readers to solve any other crimes, according to Lt. Oliver Collins, although that may change moving forward.

“This is a new technology for us, so we’re still getting used to it,” Collins said.