This feature originally ran on August 15, 2012.

TIBURON, CALIFORNIA—Tiburon, a small but wealthy town just northeast of the Golden Gate Bridge, has an unusual distinction: it was one of the first towns in the country to mount automated license plate readers (LPRs) at its city borders—the only two roads going in and out of town. Effectively, that means the cops are keeping an eye on every car coming and going.

A contentious plan? Not in Tiburon, where the city council approved the cameras unanimously back in November 2009.

The scanners can read 60 license plates per second, then match observed plates against a "hot list" of wanted vehicles, stolen cars, or criminal suspects. LPRs have increasingly become a mainstay of law enforcement nationwide; many agencies tout them as a highly effective "force multiplier" for catching bad guys, most notably burglars, car thieves, child molesters, kidnappers, terrorists, and—potentially—undocumented immigrants.

Today, tens of thousands of LPRs are being used by law enforcement agencies all over the country—practically every week, local media around the country report on some LPR expansion. But the system's unchecked and largely unmonitored use raises significant privacy concerns. License plates, dates, times, and locations of all cars seen are kept in law enforcement databases for months or even years at a time. In the worst case, the New York State Police keeps all of its LPR data indefinitely. No universal standard governs how long data can or should be retained.

Not surprisingly, the expanded use of LPRs has drawn the ire of privacy watchdogs. In late July 2012, the American Civil Liberties Union and its affiliates sent requests to local police departments and state agencies across 38 states to request information on how LPRs are used.

As I headed into the picturesque town last month for a meeting with local police, I kept a lookout for the LPRs. Tiburon Boulevard, along the city's southern coastal edge, is a lovely stretch of road overlooking a small bay that feeds into the San Francisco Bay. On summer days, cyclists and runners take to a trail along the water's edge. And It was there that I spotted the cameras, mounted on a traffic island just west of the intersection with Blackfield Drive.

Cameras point in each direction of traffic, each one trained on two lanes. The LPRs, with their sleek cylindrical design, look similar to a surveillance camera or a speed camera. They provide no indication of what they do, nor would you know by looking that have become the newest object of contention in the long-running war between "security" and "privacy." But as I drove into town to interview Captain David Hutton and Chief Michael Cronin of the Tiburon Police Department, the cameras did their silent work: my plate was scanned, parsed, and logged in the name of security.

I met Capt. Hutton in a police conference room; Chief Cronin, recovering at home after surgery, joined us by phone. First, the officers made the case that LPRs really do provide more security to towns like Tiburon. After we hung up with Chief Cronin, Capt. Hutton obligingly showed me the database entries for my own arrival.

Hitting the hot list

The entire LPR setup, including the six new cameras, cost $130,000. Funding came in part from the Marin County Sheriff's Department and the adjacent City of Belvedere; as a result, those other entities also get access to the Tiburon camera data.

The cameras run constantly, looking for hot listed plates. When they spot one, the system sends automated alerts directly to officers' in-car and in-office computers and to the Marin County Sheriff's communications desk (which does dispatching for Tiburon). The alerts provide a photo of the car in question, the date, the time, and which specific camera spotted the car.

Help us watch the watchers In the course of this story, Ars e-mailed the state law enforcement agencies of all 50 states to learn more about how LPRs are used; we received replies from just a handful. We followed up with FOIA and public information requests asking for LPR purchase orders, privacy guidelines, and other documents from ten state, ten local, and three federal agencies, including the FBI, the DEA, and Customs and Border Protection. In the course of this story, Ars e-mailed the state law enforcement agencies of all 50 states to learn more about how LPRs are used; we received replies from just a handful. We followed up with FOIA and public information requests asking for LPR purchase orders, privacy guidelines, and other documents from ten state, ten local, and three federal agencies, including the FBI, the DEA, and Customs and Border Protection. We learned, for example, that the Bismarck, North Dakota Police Department and the Hawaii State Police both deny using LPRs at all. The Delaware State Police, meanwhile, says it owns three readers. After a month, we've had relatively few responses, though many of the requests are still pending. We've created two spreadsheets outlining what we've found so far, and we have uploaded the most extensive documents (from Ohio) to Scribd. Ars readers can help us continue the investigation by querying their own local, county, and state authorities; just click here to generate a public records request letter to your local law enforcement agency. (Thanks to MuckRock for providing a nice template.) Send it in—and when you get results, feel free to share them with us for followup reporting.



Cronin explained that in a town like Tiburon, where the biggest criminal concern is property crime, knowing who is coming and going at odd hours has been very helpful to the squad. The chief added that, prior to deploying the cameras, crime was still relatively low—only about 100 to 120 thefts per year, he said. Since the cameras have been in place, that figure has dropped by "around a third," he said.

However, the system is not without flaws. It tends to yield numerous false positives because the hot list data received from the California Department of Motor Vehicles takes a long time to be updated—and because the system cannot distinguish out-of-state plates. This creates a problem if, for instance, California plate ABC123 has been reported as stolen and is on the hotlist, and then someone drives through Tiburon with Oregon plate ABC123. (Other LPR systems can distinguish the plates from different states.)

Hutton showed me an example of a unique California vanity plate that the department gets a hit on every day, because that same plate from a different state was reported stolen. The Tiburon authorities pulled over the local resident once, his story checked out, but his plate turns up again every time he enters or leaves the city.

In addition, the cameras miss some plates. When I saw the LPR system, for instance, I slowed down to get a better look. By the time I reached Blackfield Drive, I knew I had to turn around to get closer, so I made a U-turn and pulled over in the shoulder directly across from the cameras. I parked my car, and walked over to the island to snap a few pictures with my phone. I got back in my car, drove ahead 20 feet or so while still on the shoulder, and then moved over to the left turn lane, making a second U-turn to head back toward the police station. When I asked Capt. Hutton to see my own log entry, the camera had only recorded my inbound entries. Pulling over to the shoulder apparently put me out of range of the camera—a pretty easily exploitable weakness. I'd "hacked" the Tiburon Police LPRs without even trying.

Even when the cameras do score a "hit" against the hot list, few are linked to major crimes. "The vast majority of the hits that we get are not wanted cars, they're lost or stolen plates," said Cronin.

And he recognizes the system's easy susceptibility to abuse. "We could put our boss's plates in the system and every time she leaves town we could go get her golf clubs," he joked.

To prevent problems, only Cronin and Hutton can add plates to the hot list. Each time a plate is run for historical data by either an officer or requested by an outside agency, the requester has to inform the chief by e-mail. Requests are tallied in an annual report for the town council.

A multi-million dollar industry

LPR systems are doing big business at the moment. The country's largest such company, Federal Signal Corporation (FSC), which sells LPRs under its PIPS brand name, says it has sold 20,000 mobile systems across North America and another 15,000 fixed devices across the United States and the United Kingdom.

"We work with the 25 largest cities in the United States, over 100 cities in the US and over 200 in North America, including the Royal Canadian Mounted Police and in Mexico," said Tim O'Leary, a company vice president, in an interview with Ars. "We think the market is growing at 8 to 10 percent, adjusted growth rate, annually."

In its SEC filing earlier this year, FSC said its sales of LPRs were up by $2.1 million in 2010 alone. One of its primary competitors, Elsag North America, says it has worked with 1,200 agencies nationwide, while declining to state how many LPRs it has sold.

The New York Police Department began using LPR devices made by Elsag in 2006. As of 2011, the NYPD told the New York Times that it maintains 108 stationary LPRs and 130 mobile devices (Elsag's "Mobile Plate Hunter".)

The Times also wrote that in 2005, the year before LPRs were introduced, New York City had nearly 18,000 reports of stolen cars, a figure that fell to just over 10,000—a drop of over 40 percent—in the next six years. The NYPD attributes the benefits of LPR technology to being "directly responsible" for recovering over 3,600 stolen cars and for issuing summons to nearly 35,000 unregistered vehicles.

New York isn't alone in its love of LPRs. Washington, DC, with its 250 cameras, has more than one LPR per square mile, likely the highest concentration in the country.

In September 2011, the FBI reported that its Criminal Justice Information Services Advisory Policy Board (CJIS APB) had approved the use of LPRs years earlier through a pilot project conducted by the Ohio State Highway Patrol. That pilot has since expanded to "46 states, the District of Columbia, 33 local agencies, and one federal agency," which have "formal agreements with the FBI to receive the [National Crime Information Center] information for the purpose of using LPRs."

The FBI also added that a survey of its pilot partners "reported a total of 1,102 stolen vehicles recovered with a value of more than $6.5 million, as well as contraband recovered that included stolen license plates, stolen property, vehicles, drugs, weapons, larceny proceeds, suspended registrations, credit cards, and a police badge. Also as a result of the LPR technology, participating agencies located 818 subjects listed in the Wanted Persons File and 19 listed in the Missing Persons File. Another 2,611 persons were apprehended."

The recent uptick in LPR deployments is likely due to a combination of price drops—each camera can cost between $8,000 and $20,000 now—and increased federal grants for the tech. Various agencies, in particular the Department of Homeland Security, the Drug Enforcement Agency, and Customs and Border Protection have issued many millions of dollars in federal grants to state and local law enforcement to buy the hardware. (Both FSC and Elsag provide prominent links on their websites to help cops apply for these grants, too.)

Listing image by Aurich Lawson