By CHRISTEN SIMERAL
Automatic license plate readers in New York City (Flickr: lucky_dog).
WASHINGTON – Automated license plate readers—mounted on police cars, telephone poles, road signs and bridges—contain high-speed cameras that capture thousands of license plate images per minute. But they don’t stop there.
The trackers record the date, time and geographic location where each car was photographed. The plate numbers are then checked against criminal hotlists and people of interest to law enforcement, according to a July report from the RAND Corporation. If there is a match, the system issues an alert, and an officer investigates the license plate number to determine whether to take further action.
Though police use plate readers primarily to detect stolen vehicles, the data they collect are increasingly being tapped for a variety of investigations. For example, the readers also capture photos of the vehicles themselves, so law enforcement can determine vehicles in the vicinity of a crime scene, the RAND report said.
The trackers are also used to locate missing children and elderly persons by responding to Amber and Silver Alerts, support investigations of serial crimes and protect critical infrastructure sites, according to the Northern California Regional Intelligence Center.
When data is retained for an extended period of time, investigators are able to identify crime trends or patterns.
But civil liberties advocates argue that indiscriminate surveillance of the public—not just criminal suspects—is unconstitutional. According to the ACLU, “enormous databases of innocent motorists’ location information are growing rapidly.”
“Police and private companies shouldn’t be able to track everywhere we drive, and retain that information forever,” said Kade Crockford, director of the Technology for Liberty program at ACLU of Massachusetts. “But without proper legislative limits, that’s exactly what’s happening nationwide.”
License plate readers aren’t only used by law enforcement. Private companies use readers to monitor airports, gated communities, parking garages and many other locations, and police departments can purchase the data they collect, according to the ACLU. But because these for-profit commercial firms are not subject to the privacy regulations that some law enforcement agencies are, they can scan unlimited amounts and store that information indefinitely – and use it to help some private individuals spy on others to see where they go and who they are meeting with.
While a few states have passed laws restricting how long law enforcement can retain the license plate data it collects, most have no such restrictions in place.
Among the states that do enforce time restrictions, the laws greatly fluctuate. For example, in Minnesota, the State Patrol must delete its collected data after 48 hours, according to the ACLU. But in New Jersey, plate data can be retained for up to five years.
“The regulations are patchwork, and lean heavily in favor of law enforcement’s ability to warrantlessly track us,” Crockford said.
In United States v. Jones in 2012, the Supreme Court, citing the Fourth Amendment, ruled that law enforcement must obtain a warrant prior to placing a GPS tracker on cars to remotely track people’s movements. Though license plate readers are not placed on vehicles to intentionally track people, they do contain GPS technologies that track cars’ whereabouts.
“License plate readers enable a similar kind of location tracking, but it’s largely unregulated today and done without warrants or even reasonable suspicion,” Crockford said. “We need laws that require police to delete non-regulatory data after a couple of days or weeks.”
Though some police departments did consider privacy concerns when installing their tracking systems, “policies were not implemented in a systematic way and lacked input from department legal counsel,” the RAND report said. “This created uncertainty over the proper data retention and access policies.”
