License plate scanners have become a fact of life. They're attached to traffic lights, on police cars — even "repo" staff use them. All those devices have created a torrent of data, raising new concerns about how it's being stored and analyzed.
Bryce Newell's laptop is filled with the comings and goings of Seattle residents. The data comes from the city's license plate scanner, acquired from the police through public disclosure requests. He plugs in a license plate number, uncovering evidence of long-forgotten errands.
"Looks like we have you here on University Way," he says. "And this was at 3:30 in the afternoon," he says.
Newell is a PhD student at the University of Washington. He studies surveillance and is experimenting with what people can find out from stored license plate data. The scanners have already proven themselves when it comes to finding stolen cars, but Newell says with a big enough data base of this information, people could do so much more.
"As we mix data between roving systems on these patrol cars and systems mounted on, say red lights, law enforcement could get a much better picture of our individual movements," he says. "And with enough data, [police can] predict when we might leave our home and when we might be at home, for instance."
It's hardly an invasion of privacy for someone to scan a license plate. After all, that plate was meant to be public. But with millions of scans, patterns emerge. That means unusual activity stands out. And some police agencies have started experimenting with this kind of analysis.
Ron Sloan is director of the Colorado Bureau of Investigation. They've tried analyzing licence plate scans from an area near where a murder victim was found.
"We were able to do some rudimentary analysis of that data to try to determine whether or not there were vehicles that were going through the area that did not live in the area, that were from outside of the area or vehicles that that would not have been their route driving home," he says.
Sloan says it's a promising technique, but it's one he fears police will lose because of privacy fears. He and several other heads of police associations recently sent Congress a letter warning that public "misconceptions" may end up restricting police use of license plate data. Sloan says people should remember that the police are not the NSA.
"I think it's helpful for people to understand that their fears that they're being tracked or that they are somehow having their privacy violated by tracking their personal pursuits over time is not even something we have the capabilities of doing. And we have no interest in that."
But states keep passing new restrictions on how long police may store license plate data. Under these laws, police have only a few months before they have to hit delete. Still in the long run, these state laws may be moot because even as states limit the size of police databases, private ones keep growing.
Jennifer Lynch is an attorney with the Electronic Frontier Foundation. She says the nation's biggest collections of license plate data are in private hands, controlled by companies such as "Vigilant Solutions." And their information is basically unregulated.
"Private companies don't have the same responsibilities as government," she says. "Vigilant doesn't have to provide any transparency to the public about how it collects the data, how long it retains it for and who it shares it with."
These companies have been amassing license plate data from their clients — police departments around the country — as well as private contractors and other sources. That means the richest databases are held by the private sector, not the government.
But that doesn't mean the government can't use them. The Department of Homeland Security recently announced plans to use a commercial service for nationwide license plate searches. The plan is meant to answer privacy fears, since the database won't be in government hands. But that doesn't reassure Lynch.
"The fact that a private company is collecting the information doesn't really make me feel any more secure in my privacy and civil liberties if law enforcement agencies and the federal government can access it in any case."
Homeland Security wouldn't give NPR an interview about its plan to use commercial databases, but in a memorandum, it recognized "potential privacy risks" and it pledges to "follow the DHS Fair Information Practice Principles to the extent possible."
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Your license plate has been scanned repeatedly. Automatic license plate scanners have become standard equipment. They're on police cars. They're installed at intersections. And private companies use them to scan traffic, too. All this scanning has created an ocean of data about Americans' movements. And as NPR's Martin Kaste reports, police are finding new ways to use that information.
MARTIN KASTE, BYLINE: University of Washington grad student Bryce Newell has a laptop that's filled with millions of license plate scans. The scans were done by the Seattle police, and each one locates a specific car in a specific time and place, and it's all searchable.
BRYCE NEWELL: So it looks like we have a couple of hits already.
KASTE: You found me.
He plugs in my car's license, and up comes evidence of a long-forgotten errand.
NEWELL: It looks like we have you here on University Way. And this was at 3:30 in the afternoon.
KASTE: But looking up a single license plate is easy. Newell is a PhD student in surveillance - that's something you can study now. And what really interests him is what happens when you analyze millions of license plate scans at a time. He says with that many scans, you start to see larger patterns.
NEWELL: As we mix data between roving systems on these patrol cars and systems mounted on, say, red lights, the law enforcement could get a much better picture of our individual movements and, with enough data, predict where we might be or when we might leave our home or when we might be at home, for instance.
KASTE: That degree of prediction is still just theoretical. But some police agencies have started analyzing their stored plate data. Ron Sloan is director of the Colorado Bureau of Investigation. He says on one murder case his people looked at the plate scans around the area where a body was found.
RON SLOAN: We were able to do some rudimentary analysis of that data to try to determine whether or not there were vehicles that were going through the area that did not live in the area and that were from outside of the area or vehicles that that would not have been their route driving home.
KASTE: In other words, they were looking for license plates that stuck out somehow. Sloan thinks this technique is promising, and he's worried about losing it. Privacy concerns have inspired some states to limit these databases, forcing police to delete records after a period of time. Sloan is the president of the Association of State Criminal Investigative Agencies, and in March, he and other leaders of police associations sent a letter to Congress warning that the police may lose a powerful new tool because of the publics' misconceptions. That's their word. Sloan says people should remember that the police are not the same as the NSA.
SLOAN: I think it's helpful for people to understand that their fears that they're being tracked or they're somehow having their privacy violated by tracking their personal pursuits over time is not something we even have the capabilities of doing, and we have no interest in that.
KASTE: But in the end, it may not matter much that states are limiting the size of the license plate databases that police collect. That's because there's no limit on the license plate data in private hands. Jennifer Lynch is an attorney with the Electronic Frontier Foundation, and she says the nation's biggest collections of license plate data are controlled by companies such as Vigilant Solutions.
JENNIFER LYNCH: Private companies don't have the same responsibilities as government. Vigilant doesn't have to provide any transparency to the public about how it collects the data and how long it retains it for and who it shares it with.
KASTE: And there's nothing stopping these companies from letting law enforcement search their data. In fact, that's their business. The Department of Homeland Security recently announced plans to do nationwide license plate searches through a commercial service. The plan was meant to answer privacy fears about Homeland Security amassing its own giant database, but Lynch isn't reassured by that. She says it doesn't much matter to her that the license plate scans are in private hands if the government can still search them. Martin Kaste, NPR News. Transcript provided by NPR, Copyright NPR.