GALLATIN - Sumner County law enforcement officials are using high-tech cameras to create a detailed picture of the whereabouts of thousands of cars, regardless of whether they are suspected of any link to criminal activity.
Police say that this ability to capture license plates is among the most powerful new crime-fighting tools at their disposal, and that it has already led them directly to vehicles used in crimes.
It's also a type of government surveillance - spreading quickly, thanks to federal grants - that has raised privacy concerns across the country and pushed police departments to consider how the cameras and records should be used.
"I'm sure that there's going to be people out there that say this is an invasion of privacy," said Gallatin Detective James Kemp. But "the possibilities are endless there for solving crimes. It's just a multitude of information out there - to not tap into it to better protect your citizens, that's ludicrous."
As a traffic officer, Kemp learned how easy it is to gather license plates and their locations. All he had to do was head out on routine patrol while special cameras mounted atop his cruiser captured thousands of images in a day - a task that would otherwise be prohibitively time-consuming and labor-intensive for an officer.
A computer inside the car checks the nearby license plates against various crime databases, including wanted suspects, stolen vehicles and sex offenders. It can also check for tax dodgers. If the computer finds a match, a beep alerts the officer.
But that's just the start for a rapidly expanding program.
Police see far more potential in a related map database that catches all of the scanned license plates in Gallatin, Hendersonville and Sumner County, even those that didn't match the criminal lists. With that map, a detective can type in a license plate number seen at a crime scene - or even just a partial tag - and search for places where it has been spotted by cameras.
"That's the whole key: the databases," said Hendersonville police Lt. Paul Harbsmeier. "If we collect so many tags just for Hendersonville, it doesn't do any good for anybody else. Let's say we catch somebody that was involved in residential burglaries, we might check that tag to see if they were in the vicinity of any other burglaries."
That raises the question of whether a wider set of data can be built, but that's a subject law enforcement officials are only just beginning to talk about. For now the conversation hasn't crossed county lines in Middle Tennessee.
The cameras, in use in Europe since the 1990s, first appeared in Middle Tennessee in 2007 in Franklin and have become common throughout the region. But the new batch coming to Sumner County will include the first three in the region to be permanently mounted alongside busy roadways, instead of being attached to police cars.
Police said stationary scanners will read more total plates, and at all times of day, and will still send alerts to emergency dispatchers if a wanted vehicle enters the area.
According to the company behind the systems, PIPS Technology in Knoxville, a majority of reader system sales are now for fixed locations. The opposite was true when the company launched in 2005, when 90 percent of systems were attached to police cruisers, said Bryan Sturgill, company sales specialist.
Each system costs between $9,000 and $15,000. Officials in Sumner County who are overseeing the $125,000 Department of Homeland Security grant paying for the cameras said they'll get as many as their money can buy.
Legal, ethical issues prompt new policies
Harbsmeier said he has pushed for more cameras because of crime-fighting successes.
News reports show that in the first year Memphis police used plate readers, they wrote almost twice as many citations for revoked and suspended licenses than the year before. In Montgomery County, Md., police used a reader to find a suspect in the killing of a university professor. Last month, police in Downey, Calif., said they rescued a woman and her two daughters from a hotel after a plate reader pointed them to the car driven by their abductor.
But reports also point to the legal, practical and ethical questions raised by the evolving technology.
Officials in Columbia, Mo., required police to purge the plate database every 30 days, and lawmakers in Maine passed a law requiring that no plate be kept more than 21 days.
Harbsmeier said local police expect to discuss a purging policy when new installations are complete. And he said database searches are not open to all officers.
"We don't want to violate privacy and don't intend to do that," he said.
Police and Sturgill defended the readers as a tool to gather what is already public.
"A license plate is what's called plain view," Kemp said. "It's displayed right on a vehicle. It's no different than officers driving around town and looking at your tags."
"This license plate reader has no prejudice," he added.
The readers have withstood at least one legal challenge. Authorities say privacy is not guaranteed in public places - photojournalists and satellite image creators like Google have argued the same.
The difference, said Vanderbilt University law professor Christopher Slobogin, is that "the government has a lot more power that it can abuse."
"The avowed purpose is to catch people, but (police) could use the information for other purposes," he said.
Courts are starting to show reluctance toward allowing governments to continue increasing surveillance. Slobogin said gathering of information on people who haven't done anything wrong could lead to further challenges.
"We are seeing more and more government dragnet operations," he said.
Other cities also have had to figure out whether their databases are publicly available, which could open up the program to further misuse. In Connecticut, a group of 10 towns that shared their records were forced to give the American Civil Liberties Union three year's worth of records, totaling 3.1 million scans, after a request under the Freedom of Information Act.
Once the database goes public, police department restrictions about who can search through it lose their meaning, opening possibilities for commercial ventures, and also for anyone who might be looking to find where someone shops each day or parks each night.
The Sumner County Sheriff's Office oversees the local database and would fight to keep it from becoming public, said Don Linzy, chief of detectives.
"Right now it's something that we'd definitely have a problem releasing," he said. "The information is being gathered to prevent crimes. We wouldn't want anyone utilizing it just to find out something that they're curious about."
Linzy and County Attorney Leah Dennen could not rule out the possibility that scans would be subject to the state's open records act, depending on whether the information is kept in a way that connects the plates with vehicle owner names or the confidential law enforcement databases that the system uses.
"If it's just keeping a list of license plates and where they saw them, you might be able to make an argument," Dennen said.
Frank Gibson, who monitors open records issues for the Tennessee Press Association, said he had not heard of a public records request for a license plate database - but he compared the situation to a request out of Jackson, Tenn., that resulted in a court case that went before the Tennessee Supreme Court.
In that case, The Jackson Sun and the American Civil Liberties Union sued police for the right to look at a card file that officers created by stopping cars and interviewing people who happened to venture into particular parts of the city.
"The court held that those files would be a public record except in cases where the card was part of an ongoing criminal investigation," Gibson said.
The Tennessee Highway Patrol has used license plate readers for about one year, finding more success than the departments in Sumner County.
Using 24 readers in cruisers across the state, the THP has arrested wanted suspects and sex offenders and recovered stolen vehicles, said spokeswoman Dalya Qualls.
In more than a year in Gallatin, Kemp hit on just one stolen license plate - sort of.
When the computer alerted him, he made a traffic stop and, like the camera, saw that the numbers on the plate were a match. But it was made out of cardboard, an imitation created by the man who had reported his plates stolen.
"It looked really realistic," Kemp said. "With black Sharpie marker he made it just a perfect fit."
Kemp did assist on a reader-related arrest out of Franklin. He said a witness to a hit-and-run at a Target store gave police a partial tag number.
Police ran it through the database and found all records of that combination captured by their cameras. One plate showed up often in that area, leading police to a suspect who happened to live in Gallatin.