Motorists, on the other hand, don't know much about the records police officers have collected through the use of these machines. These records are getting harder to obtain.
Even though the vast majority of these records involve ordinary drivers not accused of any crimes, law-enforcement officials are increasingly withholding license-plate reader data from public purview. Three court cases filed within the past month could go a long way in determining whether the public has a right to see this data.
"What it says is that we're all suspects in waiting," – Steve Orr
Advocacy groups, reporters and private citizens behind these lawsuits all believe the records will shed light on how police officers collect and utilize records that can paint detailed portraits of a motorist's private life. But at a time when more Americans are growing concerned over widespread surveillance techniques and mass collection of personal data, authorities are justifying their decisions to keep this information secret by claiming the records are all part of ongoing investigations.
In Monroe County, New York, authorities denied an open-records request from a reporter at the Rochester Democrat and Chronicle who had sought license-plate reader records from his own vehicle, those of six of his colleagues and two county vehicles. In denying the newspaper's Freedom of Information request, county officials argued release of the records could hamper ongoing law-enforcement investigations. Steve Orr, the reporter who filed the request, said neither he nor his colleagues are under investigation.
"What investigation is that? Most people in the database are not, and haven't been associated with an investigation," he said. "There's no criminal concern here. ... They're saying, 'OK, maybe there's not an investigation now, but there could be one down the road.' ... What it says is that we're all suspects in waiting."
That's the crux of a legal position that won approval from a judge in California Superior Court in August. Arguing against the release of records, the Los Angeles Police Department and Los Angeles Sheriffs Department said all cars are under suspicion, and as such, license-plate reader records are exempt from laws that would otherwise mandate their disclosure.
"An investigation isn't just because somebody says, 'Hey, we've got this database and maybe someday your car will get stolen," – Chris Thomas
Los Angeles deploys hundreds of automated license plate readers that, collectively, produce approximately 3 million records every week. The Electronic Freedom Foundation, one of two organizations seeking records in the lawsuit, says it's inconceivable the city's police force could be conducting so many investigations each week, and believes the Fourth Amendment should protect against overly broad searches and surveillance.
"You have a situation where 99.8 percent of these records have nothing to do with any kind of criminal investigation and the purpose of data collection is to solve crimes," says Jennifer Lynch, senior staff attorney with the EFF.
Los Angeles: All cars under suspicion
Here's how the automated license-plate readers work: Cameras are triggered by reflective material in license plates, and character-recognition software discerns plate numbers and attempts to match them against "hot lists" of stolen cars, vehicles sought for Amber Alerts and known fugitives. When a match is found, it sends an alert.
On some level, they do work. During the first phase of a study ( PDF) conducted by the Police Executive Research Forum in the car-theft hotbed of Mesa, Arizona, the readers scanned 457,368 plates and had 24 hits, a hit rate of .00005 percent. But the same study also concluded license-plate readers hold "a limited amount of promise for law enforcement" because of costs involved, technical difficulties and problems presented by false positives.
Lynch is concerned with both the application of the technology and with the length of time law enforcement holds onto the collected data. In an ideal scenario, she said police agencies could use the data for 48 hours before it is deleted. "You don't need to hold onto the data for any real length of time to search for stolen vehicles," she said.
But most law enforcement agencies retain the data anywhere from two to five years, if they have restrictions at all. In that time, they can pool the data with other agencies, which in turn may have different regulations on the length of time they can store data.
"If I'm not being investigated for a crime, there shouldn't be a secret police file on me," – Michael Robertson
Over time, dozens of records for a given license plate can detail the habits of the driver. Law enforcement can know where they work, who they associate with, which doctors they see, what political protests they attend, where they attend religious services and where they stop for their morning cup of coffee.
Without public scrutiny of how such data is handled, it is too easy for the government to overreach, the American Civil Liberties Union says. "The knowledge that one is subject to constant monitoring can chill the exercise of our cherished rights to free speech and association," it wrote in a 2013 report ( PDF).
The ACLU and EFF are the two plaintiffs in the Los Angeles case. Last week, they filed a petition to appeal the August ruling that allowed officers to claim their records are all part of investigations. No court date has yet been set.
In their initial request made under California open-records law, the two organizations asked for one week's worth of data from the license-plate readers, saying a large amount of data is necessary to inform the public about how the systems are used.
For example, without substantial data, they cannot learn if police officers are scanning more plates in one neighborhood versus another, nor gain more insight on how many records might exist for an average vehicle. Lynch says seeing millions of data points on a map better illustrates the vast scope of the readers and their intrusiveness.
"If I say 3 million scans a week, it's hard to wrap your head around that," she said. "There's nothing comparable to seeing what that data looks like."
But because police claim the data is investigative in nature, Judge James C. Chalfant wrote the potential harm to those investigations outweighs the public's value in seeing that sort of analysis from the collected data.
Can you see your own records?
The request for records is different in Rochester. Unlike in Los Angeles, Orr, the reporter, didn't ask for a wide swatch of the county's license-plate reader records, which numbered 3,765,555 as of July. He asked for specific existing records for his own vehicle, those of six colleagues and two county vehicles.
County officials issued a two-part rejection to that request, first saying they were off limits because disclosure would infringe upon the privacy of the motorists whose license plates were scanned, even though Orr and his colleagues had signed waivers authorizing the release of their own information.
That claim echoes a September case in San Diego, California, in which a judge rejected a records request from Michael Robertson, a tech entrepreneur, who had asked only for records for his own vehicle.
"If I'm not being investigated for a crime, there shouldn't be a secret police file on me," Robertson told The Associated Press. "That's crazy, Nazi police-type stuff."
There's a degree of irony in the privacy claims. Courts have long ruled that, generally speaking, motorists have diminished rights to privacy in their cars. One of the many ramifications from that precedent has been the proliferation of license-plate readers. From a legal perspective, these cameras can operate specifically because a car's license plate is considered in public view.
Authorities are justifying their decisions to keep this information secret by claiming the records are all part of ongoing investigations.
"The justification that law enforcement often cites when people question whether they have a right to take an image of peoples' license plates is basically that of course they do, the plates are in plain sight and there's nothing private about them," Orr said. "That's their rationale for legally doing it. At the same time, when someone asks to see the records, they turn around and say it's private. To me, that's illogical."
A Monroe County spokesperson declined to comment on the case.
Privacy isn't the only reason police in Rochester denied the records request. As in Los Angeles, they said the information was part of an investigation, and therefore exempt from disclosure. The newspaper's attorneys filed a court motion last week, asking a judge to compel the release of the data. At the heart of their argument is the definition of what constitutes an investigation.
"An investigation isn't just because somebody says, 'Hey, we've got this database and maybe someday your car will get stolen,'" attorney Chris Thomas said. "It needs to be about an identified crime that has been committed or is being investigated. It can't be some blunderbuss claim that this vehicle, this license plate, this person could someday be the perpetrator or victim of a crime, and for that reason every record in this database is part of a gargantuan, nebulous, undefined, undistinguishable investigation."