License plate readers capture loads of data. How long do cops keep it?

The Los Angeles Police Department is among dozens of California's law enforcement agencies that have failed to make their license plate surveillance policies public, despite a new state law requiring disclosure.

The law, passed last year by the California Legislature, was an attempt to keep tabs on an increasingly common surveillance tool: automated license plate readers. And last week, San Francisco's Electronic Frontier Foundation checked on which agencies have complied with the law and what their policies state. They found about 80 law enforcement agencies that have posted their policies and that nearly as many believed to use the devices didn't.

Many agencies in Southern California did not post their policies, including LAPD and Manhattan Beach, which just made plans to spend $400,000 to gather vehicle license plates in the beach town.

The state law requires agencies to share policies as long as they have websites, but doesn't include strong penalties for failing to post them.

Use of the license plate readers has grown in recent years.

If you drive around Southern California, there's a good chance that your license plate has been captured by police surveillance cameras—possibly hundreds of times. Automated license plate readers, which are often mounted on squad cars and capture plate numbers and locations, are common across the region.

Law enforcement officials say the cameras are an important new tool. A note introducing the La Verne Police Department's policy says that readers capture data on vehicles, not people.

The plates police scan are typically checked against lists of vehicles connected to stolen vehicles or missing persons cases.

License plate readers make police more efficient, said Darren Wyatt of the Anaheim Police Department. "If you're driving around in a patrol car, you have one set of eyes," Wyatt said. "The cameras are around the entire vehicle."

"It's a technology that makes an officer's job much easier," he said.

Mark Stichter of the Orange County Sheriff's Department sounded a similar note, saying the license plate readers are more vigilant and efficient than the note pads and pens deputies use.

Stichter added that while cameras capture data, agencies don't make their data public. "It's not throwing that personal information out for everybody to read," he said.

The amounts of data captured by the devices can be massive. Police in Long Beach have about 50 readers, which in 2015 read plates about 23 million times, according to the LBPD's Brad Johnson.

At the Ventura County Sheriff's Department, readers on 23 patrol cars read 9,649,383 license plates in 2015, according to the department's Denise Sliva.

TABLE: Click here to view how long SoCal law enforcement agencies hold on to license plate data 

Mike Katz-Lacabe, an activist and EFF member who participated in the search, said that requiring agencies to post policies is a good first step, and that little is still known about how police use the technology.

He added that that kind of information captured could be used to piece together a detailed picture of a person's life, allowing law enforcement to deduce everything from church attendance to extramarital affairs.

The LAPD has been reluctant to share information about license plate readers. Together with the the Los Angeles Sheriff's Department, the agency has fought a lawsuit from the EFF and American Civil Liberties Union to share one week's worth of license plate reader data.

The LAPD did not respond to inquiries by KPCC. 

Police in Glendale, Santa Ana, Downey and other local cities also don't have their policies available online, the EFF found.

Katz-Lacabe said the policies are important because they show how long agencies retain data.

"If you keep it for a short period of time, there's less concern about that," he said.

KPCC reviewed the policies of agencies around Southern California for the length of time they store license plate data. Those windows vary, and agencies carve out exceptions for data that's already involved in or likely to be called upon in civil or criminal cases.

In the region, most agencies ditch license plate reader data after a year, a handful keep it for two, and the Los Angeles County Sheriff's Department plans to retain it for five years—hard drive space permitting.

Katz-Lacabe said that readers rarely turn up the actual plates police are looking for, citing an ACLU report that said more than 99 percent of scans aren't hits. "All of that information is essentially being collected on people who are not being suspected of or charged with any crime," he said.

Length of law enforcement agency license plate data retention 

Source: Department policies

Search automated license plate reader policies in SoCal