Who Scans the Scanners?

In a span of 10 seconds, more than 30 cars pass a patrol vehicle stationed in Union Square. Without the officer inside lifting a finger, a system installed in her vehicle snaps pictures of each passing license plate and compares them against lists of wanted and unregistered vehicles. If one of the vehicles is a match, the system alerts the officer, who then verifies the hit and conducts a stop.

Regardless of whether the system registered a hit, it catalogs all photos and plate numbers, saving each scanned plate to a database along with geotagged location.

The whole process is instantaneous and conducted in real-time: as cars pass, the automated license plate recognition (ALPR) reader compares each to the so-called hotlists. The ALPR system also scans as the officer drives, reading and recording plates on vehicles she passes while on routine patrol or en route to a call.

This has been happening in Somerville since 2008 and is the reality of next-generation public safety and traffic enforcement using ALPR. It is data-driven, automated and efficient. According to Somerville police brass, ALPR is a critical “force multiplier” that allows officers to quickly and safely run license plates. Privacy advocates in Somerville and across the country are concerned about ALPR, though, because of the technology’s potential for misuse and abuse.

So what role should ALPR play in law enforcement in Somerville? Activists say it depends on how SPD uses the technology, and what protections are in place to ensure that private data is not abused. With the department’s program having gone on temporary hold in September, the time for Somerville to examine ALPR – and for SPD to enact appropriate policies that capitalize on the technology’s promise while protecting civil liberties – is now.

Automated license plate recognition: The basics

Nationwide, as many as a third of police departments already use license plate readers. Interest in ALPR continues to build, bolstered by federal grants and advocacy from law enforcement organizations and manufacturers. Police in at least sixty cities and towns in Massachusetts use ALPR, including Boston, Quincy, Springfield and Brookline, as do the State Police and the Department of Transportation.

Somerville Police Department currently has three mobile ALPR systems. The first two were bought in 2008 at a cost of $25,000 each. The department added a third scanner in 2009. The readers are capable of recording as many as 1,500 license plates per hour, according to manufacturer specifications.

ALPR scanners use high-speed cameras and character recognition software to convert photos of license plates into text, which the system then compares to plates of interest to law enforcement. Somerville’s ALPR compares scanned plates to a number of hotlists, including statewide lists of wanted and stolen vehicles, as well as databases of uninsured cars and vehicles with lapsed registration. The operating officer is alerted if a passing vehicles registers a match, which must then be verified prior to a stop.

While only hotlist matches result in traffic stops, all data are saved to system memory, including the plate number, date, time and location at which the vehicle was scanned.

It is this last step that worries privacy advocates most, since stored location data can be aggregated easily into a searchable database of where and when cars – and by extension their owners – have been. The Massachusetts Pirate Party, which lobbies against post-9/11 invasions of privacy by law enforcement, opposes the use of ALPR for just this reason. Mass Pirates Captain James O’Keefe, a Somerville resident, characterized ALPR as an example of “creeping surveillance technologies,” and worries that similar technologies “encroach on our ability to live our lives free of constant government surveillance.”

Kade Crockford, who heads the Technology for Liberty project at the American Civil Liberties Union of Massachusetts (ACLUM), insists that “the worst-case scenario – vast databases with records of movements of massive numbers of people – is already happening.”

Law enforcement nationwide have shown they recognize the boon historical ALPR data could prove for investigations, particularly if agencies pool their vehicle location data. Two vast regional networks – SOSINK (Southwest Ohio/Southeast Indiana/ Northern Kentucky) in the Midwest and ARJIS (Automated Regional Justice Information System) along California’s border with Mexico – already allow dozens of law enforcement agencies to access each others’ ALPR databases. Additional statewide and regional data-sharing arrangements are in the works across the country.

There is currently no such network in Massachusetts. But given the widespread use of license plate scanners in Massachusetts, a statewide ALPR network is certainly a foreseeable possibility. If such a network were developed, would SPD allow other law enforcement agencies to access vehicle location data collected around Somerville?


No written policy, only guidelines

SPD says that the answer is a definitive “no.” But despite having employed them for four years, the Somerville Police Department has no written policy to govern usage of ALPR systems or data. While current guidelines address some privacy issues, their plasticity and a lack of public consultation raise accountability concerns for future use of this powerful technology.

Deputy Police Chief Paul Upton makes a strong case for ALPR’s usefulness. He explains that the automated scanners both magnify his officers’ capacity to run plates and bolster safety by eliminating the need to type and drive simultaneously. “This is good technology,” Upton said. “It makes our department more efficient, and lets us do more with less.”

He said the scanners have allowed SPD to take a significant number of unregistered and uninsured vehicles off the streets. And it has helped recover stolen cars and apprehend suspects with active warrants.

By Upton’s view, Somerville citizens should not have any privacy concerns regarding ALPR, since SPD is “not interested” in keeping historical location data and access is restricted through the office of Chief Pasquarello. Under current guidelines, Somerville police keep ALPR data for 14 days, and Upton said that his department has never shared the data with other agencies.


14 Days

Somerville’s14-day retention of ALPR data mitigates considerably the risk that police might use this technology to track citizens, whether as an official investigation tool or for more nefarious purposes by a rogue officer. The Boston Police Department, for instance, whose ALPR systems scan 3,600plates daily, keeps its data for at least 90 days. Other law enforcement agencies around the state keep it for two or more years, and some retain their ALPR data indefinitely.

ACLUM staff attorney Laura Rótolo called SPD’s retention guidelines “a good start,” but she has other concerns. “Ideally,” she said, “the police should never gather or store data on vehicles where there is no hit in a database of stolen or wanted vehicles.” O’Keefe said that “14 days is better than 14 months or 14 years,” but would prefer that SPD not keep the data in the first place.

City Hall insists that the status quo is sufficient when it comes to ALPR. Mayoral spokesman Tom Champion said that the technology has been used “successfully and without incident” for years. Deputy Chief Upton echoed the sentiment, suggesting that he has heard “no complaints” about the use of ALPR or SPD’s lack of a written policy.

But without a formal public policy in place, the guidelines that govern ALPR in Somerville amount to little more than departmental convention. SPD did not settle on its 14-day data retention standard in consultation
with the public or civil liberties advocates, nor is the department’s resolution not to share ALPR data a permanent or binding one. There is nothing save personal scruples to stop these guidelines from being changed without notice.

Civil liberties advocates are not the only ones to have called for greater transparency and clear privacy protections. The International Association of Chiefs of Police (IACP), which develops policy recommendations around law enforcement issues, has advocated extensively for federal funding of ALPR systems. But in an October report, IACP highlighted the potential “chilling effects” of ALPR on civil liberties without appropriate policies in place. The IACP called for management of ALPR in consultation with the community, specifically recommending that “policies must be developed and strictly enforced to ensure the quality of the data, the security of the system, compliance with applicable laws and regulations, and the privacy of information gathered.”

Somerville might take a page from Brookline, who put the issue of ALPR to vigorous debate last summer. Recognizing the need for oversight, the Brookline Board of Selectmen authorized police to implement license plate scanners on the condition that it report regularly to a civilian privacy committee, which also audits use of the town’s surveillance cameras. For a year ahead of his ALPR purchase, the Brookline police chief shaped a departmental policy in close consultation with the Board of Selectmen and the town’s residents.

With Somerville’s ALPR program shelved for now, the city has the opportunity to reexamine license plate readers and privacy implications around their current and future use. Drafting a transparent, written policy would allow for public scrutiny that is currently lacking.

This report was produced in partnership with Boston-based public records service MuckRock