TIBURON, Calif. -- There's only one main road to this tiny upscale town, and every time a vehicle drives in or out -- rain or shine, day or night -- a police camera snaps a digital photo of its license plate.
Welcome to Tiburon! Snap.
Thanks for visiting! Snap.
A computer scans the symbols and compares them with a database of stolen vehicles and other crime records, then alerts police if there's a hit. The local police chief says the cameras have virtually stamped out auto thefts in this town, situated on a peninsula north of San Francisco.
License plate scanning could be coming to your town, too, if it hasn't already.
Revelations last month that the National Security Agency is capturing records of millions of e-mails and phone calls has prompted debate about privacy. Now come details about the rapidly expanding police use of automatic license plate readers (ALPRs). Nearly three in four police agencies say they use them, and more say they're planning to install them soon on police cruisers or, as in Tiburon, on stationary poles at busy intersections.
They cost as little as $15,000. One manufacturer says its cameras can capture images of up to 1,800 plates per minute across four lanes of traffic and at vehicle speeds up to 150 mph.
Because ALPR technology is so neat and seamless, its adoption by police is often less a result of civic decision-making than simply "a purchasing decision," says Peter Bibring, an American Civil Liberties Union (ACLU) attorney in Los Angeles who is suing the city police and county sheriff's office for ALPR records. "There hasn't been a public debate on license plate readers and how they should be properly used," he said.
As in L.A., they've expanded nationwide: A 2012 survey by the non-profit Police Executive Research Forum found that 71% of police agencies now use them and that 85% plan to either acquire one or increase their use within five years.
Police say the devices are effective at recovering stolen vehicles and bringing auto theft rates down. In one Sacramento shopping mall, ALPRs snapped pictures of about 3million plates in 27 months, identifying 51 stolen vehicles. Police also say they've used ALPRs to solve criminal cases, including homicides.
Civil liberties activists worry the data could be used to track innocent drivers' whereabouts and private lives. Even the International Association of Chiefs of Police has said there's a potential for invasion of privacy, as ALPRs can snap pictures of a car at a political gathering, psychologist's office, abortion clinic or church.
"This is a way to track all Americans all the time, regardless of whether they're accused of any wrongdoing," says Catherine Crump, an ACLU staff attorney in New York. She called ALPRs "the most widespread location-tracking technology you've probably never heard of."
In the first nationwide look at the phenomenon, the ACLU said this week that ALPRs "have been proliferating around the country at worrying speed" and that the system is ripe for abuse by police. The ACLU says that in 45 states, there are no laws on how long police can keep the records. Because police in many areas insist on holding on to the data for years -- or even indefinitely -- the group fears the rise of enormous databases of motorists' location information.
Jennifer Lynch, an attorney with the Electronic Frontier Foundation, a co-plaintiff in the Los Angeles lawsuit, says police routinely hold on to surveillance data even after the original uses are satisfied. "They find it's useful and then they think, 'Why don't we keep it as long as we can?' " She noted that an effort last year by a California lawmaker to limit ALPR data retention to 60 days failed after police and hardware manufacturers lobbied against it.
Here in Tiburon, Police Chief Michael Cronin says car thefts "pretty much dropped off the radar" after he installed the system in 2009.
On the streets of Tiburon, opinion is divided, if slightly in favor of the cameras. Andrew Chermaki, 62, visiting from Cambria, Calif., says the system "definitely does not make me feel safer. It feels more like a part of this slow progression of technology encroaching into our lives."
However, Mary Grant, 48, says the system "gives me a sense of comfort" as a parent. "I might have said 'No Big Brother watching us!' when I was younger, but now I'm in my 40s, and I have a child." She adds, "As American citizens, I think we have a much higher sense of our privacy than is realistic. I think if we really knew what was going on, we'd be amazed."