Starting on January 1, 2016, California law enforcement agencies and companies will have to take new steps to make their automated license plate reader (ALPR, or LPR) policies more transparent to the public.

Among other things, under Senate Bill 34, any "ALPR operator" will be required to:

Implement a usage and privacy policy in order to ensure that the collection, use, maintenance, sharing, and dissemination of ALPR information is consistent with respect for individuals’ privacy and civil liberties. The usage and privacy policy shall be available to the public in writing, and, if the ALPR operator has an Internet Web site, the usage and privacy policy shall be posted conspicuously on that Internet Web site.

Law enforcement agencies must also include the "length of time ALPR information will be retained and the process the ALPR operator will utilize to determine if and when to destroy retained ALPR information."

Other changes require that cities disclose if their ALPR database is breached in some way and provide an avenue for citizens to sue the police if their data is compromised.

Ars contacted several law enforcement agencies around the state, but they did not immediately respond. Livermore, California-based Vigilant Solutions, which claims the world’s largest private license plate reader database, also did not respond to Ars’ request for comment.

Specialized LPR cameras mounted in fixed locations or on police cars typically scan passing license plates using optical character recognition technology, checking each plate against a "hot list" of stolen or wanted vehicles. The devices can read up to 60 plates per second and typically record the date, time, and GPS location of any plates—hot or not. (There have been incidents where LPR misreads have led to dangerous confrontations.) Some cities have even mounted such cameras at their city borders, monitoring who comes in and out, including the wealthy city of Piedmont, California, which is totally surrounded by Oakland.

The technology has been around for some time now: the Los Angeles Sheriff's Department began testing ALPRs in June 2005.

Just be up front about it

The new policy change, which was signed into law by Gov. Jerry Brown earlier this month, is one in a series of surveillance-related reforms lauded by privacy advocates across America’s most populous state.

"We’re not going to have to do these huge fishing expeditions and write them to ask them if they have it and deal with their rejections," Dave Maass, a researcher at the Electronic Frontier Foundation, told Ars.

"It’s going to have to be online, and so if anyone wants to go jurisdiction by jurisdiction to find out if they have these or not, they can."

In addition, the bill’s author, Senator Jerry Hill (D-San Mateo), was pleased that the governor signed the bill.

In a statement, Hill also highlighted some of the bill’s other features.

"SB 34 provides protections to prevent automatic license plate readers from infringing on Californians’ privacy and civil liberties, while balancing the technology as a legitimate crime fighting tool," he wrote in an e-mail.

"Specifically, SB 34 requires a public agency considering the use of automatic license plate readers to provide an opportunity for public comment at a regularly scheduled public meeting of its governing body," he continued. "The bill also prohibits public agencies from selling the data collected by the technology, because data collected with publicly funded technology that is intended to help fight crime should not be made available to benefit businesses using automatic license plate readers for commercial purposes."

One local activist, Mike Katz-Lacabe, who was captured by an ALPR system in a now-famous photograph of him and his daughters in front of their home, was thrilled to hear of the new law.

"In the city where I live—San Leandro, California—a mobile license plate reader was acquired and put into use in 2008," he told Ars.

"It wasn’t until a Wall Street Journal article was published in 2012 that members of the City Council became aware of the technology," he said. "The purchase of the license plate reader never appeared on a City Council agenda and was never publicly discussed by the City Council. This bill is the first step needed to ensure that the public knows about the acquisition and use of license plate readers. That needs to happen before elected officials can have the discussions with their constituents and implement appropriate policies that include provisions for privacy protections, oversight, and accountability."

"Defining LPR data as personal information makes sense, as our vehicles are essentially an extension of our identity and location. If you have information about my car collected by a license plate reader, you have information about me, where I’ve been, and with whom I associate."