License Plate Readers Spark Privacy, Public Safety Debate

By Maggie Clark, *Stateline Staff Writer

Police have used cameras that read the license plate s on passing cars to locate missing people in California, murderers in Georgia and hit-and-run drivers in Missouri.

A City of Alexandria Dodge Charger police car equipped with mobile ANPR produced by ELSAG North America (Mobile Plate Hunter 900). Two forward facing ANPR units are mounted on the trunk of this vehicle. 2010

The book-sized license plate readers (LPRs) are mounted on police cars, road signs or traffic lights. The images they capture are translated into computer-readable text and compiled into a list of plate numbers, which can run into the millions. Then police compare the numbers against the license plates of stolen cars, drivers wanted on bench warrants or people involved in missing person cases.

Privacy advocates don’t object to police using LPRs to catch criminals. But they are concerned about how long police keep the numbers if the plates don’t register an initial hit. In many places there are no limits, so police departments keep the pictures — tagged with the date, time, and location of the car — indefinitely.

The backlash against LPRs began in earnest this year, as three more states limited law enforcement use of the systems and in some cases banned private companies from using the systems, for example, to track down cars for repossession. So far, five states limit how the cameras are used, and the American Civil Liberties Union anticipates that at least six other states will debate limits in the upcoming legislative session.

In New Hampshire, police and private companies (with the exception of the tolling company EZ Pass) are forbidden from using license plate readers. Utah requires police to delete license plate data nine months after collection. In Vermont, the limit is 18 months and in Maine it is three weeks. Arkansas police have to throw out the plate numbers after 150 days and parking facilities are the only private companies allowed to use the technology. 

“It’s been surprising to find out how license plate readers are being used and how long the data is being kept,” said Michigan state Rep. Sam Singh, a Democrat, who is sponsoring legislation to limit police in his state from keeping license plate numbers for longer than 48 hours. Police are using the cameras in a handful of Michigan cities, including Detroit and East Lansing.

Singh’s legislation would also make the license plate data exempt from public records requests so that, for example, divorce attorneys couldn’t request license plate reader data to confirm where a spouse was at a particular time. The bill, which is still in committee, also would limit how private companies can use license plate readers to track down cars for repossession. 

“We just fundamentally believe that Americans don’t need to be watched unless there’s probable cause of wrongdoing,” said Shelli Weisberg, legislative director for the Michigan ACLU, which supports Singh’s bill.  “We don’t need a ‘just in case’ database. That just turns democracy and our sense of due process on its head.”

NSA Fallout

The debate over license plate readers and other law-enforcement technologies is a local expression of a national wariness about government spying in the wake of revelations about the National Security Agency’s far-reaching data collection on ordinary citizens across the world.