Anyone who drives past a police squad may have been tracked without knowing it, and the scanners that record a car's license plate are raising important questions about the balance between public safety and privacy.
Each day in the Twin Cities, police photograph thousands of license plates. That means big brother knows exactly where you've been -- date, time and location.
Minneapolis police started the tracking trend three years ago, using optical scanners mounted on top of squad cars that can capture up to 2,000 plates per minute, even at 65 mph.
Now, police departments in St. Paul, Bloomington, Maplewood and Roseville are also using the scanners, storing the information for up to 90 days too. In Minneapolis alone, that data encompasses 2.1 million license plates.
That raw data is a metadata gold mine, and it was considered public until last March when the Department of Administration expressed concerns about stalkers and predators. While that data is private now, some of the people who were after it -- and got a hold of it -- is surprising.
"There are a lot of mathematical, analytical functions in those languages that would allow me to analyze that data," Sean Bailey, of Pittsburgh, told FOX 9.
Bailey, a 15-year-old computer whiz, was trying to get his hands on the data because he wanted to use it as a way of finding where someone most likely lives. He says it's possible to predict where a car will go by reading patterns in the license plate data, and he's not the only one who had big plans for the information.
Mitre Corporation, a non-profit information technology company which contracts with the departments of Defense and Homeland Security, also wanted access. A spokesperson for the company said they intended to use it for an "internally-funded research project on data mining to support law enforcement."
Specifically, they were interested in how license plate readers could have helped catch the sniper in Washington, D.C., by yielding a short list of possible suspect license plates.
Locally, Bloomington police used the license plate technology to catch Garret Parks, who was threw items from his car -- including a metal vise that hit and injured an Iraq war veteran.
Yet, privacy expert Rich Neumeister wonders whether government should be collecting millions of records on law-abiding people, and whether an arrest in one case or another is worth scooping up all that raw data on everyone.
As the debate over NSA surveillance illustrates, that's the main dilemma of metadata: Is it worth diverting an entire river of data just to eventually capture a few fish?
Even a 15-year-old in Pennsylvania who loves data admits he questions the wisdom of such collection.
"There should definitely be an opt-out if people want their personal data scrubbed from the record," he said. "In some cases, it could be construed as an invasion of privacy."
The license plate scanners are becoming a big issue nationwide. In Los Angeles, the American Civil Liberties Union is suing the police department to find out how much data it's collecting and if they're doing it in front of churches or mosques.
On the other hand, the affluent town of Piedmont, Calif., is considering placing the cameras at the border with Oakland to photograph every plate coming into town.