For the first time, the number of license tag captures has reached the millions, according to a study published Wednesday by the American Civil Liberties Union based on information from hundreds of law enforcement agencies. Departments keep the records for weeks or years, sometimes indefinitely, saying they can be crucial in tracking suspicious cars, aiding drug busts, finding abducted children and more.
Police departments throughout southwest Ohio use the license plate readers and have varying policies retaining the data the readers collect.
Attached to police cars, bridges or buildings — and sometimes merely as an app on a police officer’s smartphone — scanners capture images of passing or parked vehicles and pinpoint their locations, uploading that information into police databases.
While the Supreme Court ruled in 2012 that a judge’s approval is needed to use GPS to track a car, networks of plate scanners allow police effectively to track a driver’s location, sometimes several times every day, with few legal restrictions. The ACLU says the scanners are assembling a “single, high-resolution image of our lives.”
“There’s just a fundamental question of whether we’re going to live in a society where these dragnet surveillance systems become routine,” said Catherine Crump, a staff attorney with the organization. The group is proposing that police departments immediately delete any records of cars not linked to any crime.
Although less thorough than GPS tracking, plate readers can produce some of the same information, the group says, revealing whether someone is frequenting a bar, joining a protest, getting medical or mental help, being unfaithful to a spouse and much more.
Dayton police have 11 automated license plate readers, four of which are currently deployed, said Maj. Mark Ecton, the department’s chief of staff. The remaining units will be installed on new cruisers as they are rolled out, he said.
Ecton said the readers provide officers an automated method for identifying license plates and vehicles that may be connected to criminal activity.
“We’ve had officers drive down the street and receive an alert that a stolen car has just passed them,” Ecton said. “They have recovered cars or apprehended individuals who were wanted on serious crimes,” he said.
There is a limited retention period for the data, but Ecton said the reader information has proved useful days and months after a crime has occurred.
Like the use of DNA evidence, automatic license plate reader technology is a tool to assist officers “by doing something the technology is much more capable of doing than the human being,” said Sgt. Ed Buns, the Hamilton police department’s traffic section supervisor.
Hamilton police have successfully used their two cruiser-mounted automatic license plate readers to identify vehicles leaving crime scenes, Buns said.
“If you pass 30 cars, there is no way physically you can write every one down,” he said. “You can look at them and see who is leaving the scene of a robbery or homicide or something like this. That is where we have seen benefit to them.”
Buns declined to share details of those cases because they are currently in process.
As the technology becomes cheaper and more widespread, even small police agencies are able to deploy more sophisticated surveillance systems. The federal government has been a willing partner, offering grants to help equip departments, in part as a tool against terrorism.
Law enforcement officials say the scanners are strikingly efficient. The state of Maryland told the ACLU that troopers could “maintain a normal patrol stance” while capturing up to 7,000 license plate images in a single eight-hour shift.
The ACLU study, based on 26,000 pages of responses from 293 police departments and state agencies across the country, found that license plate scanners produced a small fraction of “hits,” or alerts to police that a suspicious vehicle had been found.
Staff Writer Dave Larsen contributed to this report.
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