You are being trackedIn a report released last week, the ACLU describes in chilling detail the rapidly expanding law enforcement use of automatic license plate recognition (ALPR) systems nationwide. Originally designed to automatically scan surrounding vehicle plates for comparison against a “hot list” of wanted vehicles – such as those reported stolen or owned by a person for whom an arrest warrant was outstanding – ALPR devices have now become a seemingly indispensable investigative tool. While law enforcement use of emerging technologies is not in itself a problematic practice, how those tools are used can be of great concern.
How it worksWhile the underlying algorithms that make ALPR possible can be highly complex, the basic technological principles are fairly straight forward. Essentially the technology involves a camera, a computer, and a piece of software designed to “read” any vehicle license plates picked up by the camera. Mounted on police cruisers or road fixtures such as overpasses or street lights, sets of connected cameras can effectively scan the license plates of every vehicle within range.
While one or two such systems pose relatively little threat to everyday privacy, hundreds of such cameras are now active all over LA County and are being used by the LAPD, the LA County Sheriff, and the California Highway patrol. Together, the accumulated data from all these sources (all of which is shared between departments and even the Federal government through a backend server system known as BOSS) can be mined by law enforcement and the results used to paint a picture of the movements of any citizen who drives on public roads – going back months or even years into the past.
ALPR grows upOriginally developed in England as an offshoot of the massive public surveillance camera system long in use there, ALPR was first put to practical use in the late 1970s. However, despite its early potential, the prohibitive cost of computing and camera equipment made widespread use of the technology impractical until the last decade. Broad public knowledge of the practice is still underdeveloped. News reports were covering ALPR back in 2006, including an article published in Wired; but even at that relatively late date, the more nefarious aspects of the technology were still all but unknown. Even the ACLU is quoted in that article as being unconcerned about the practice at the time stating that there had been no legal challenge because the activity was not illegal – what a difference a few years can make.
Lost cost digital storage and the rise of privacy concernsMuch has changed since 2006 to make ALPR technology a much bigger concern today than it was just a few years ago. Of primary concern is the rapidly decreasing cost of huge computer storage capacity. Once a barrier to privacy invasion, digital storage technologies now allow law enforcement to maintain the records of their scans indefinitely; a possibility many agencies are all too happy to embrace. In the early days, hits were only scanned against a short list of “hot” vehicles. Today, everything has changed. Now, every single scan is logged into a database with some jurisdictions storing more plate data points per year then there are residents under their protection. What was once a benign police tool has now become every bit as controversial as the NSA phone surveillance program revealed earlier this year.
Indefinite storageWhile police agencies tout the many legitimate uses of the ALPR technology, privacy concerns about the system stem not from its legitimate uses but largely from the length of time for which collected data is retained. Because every scanned plate is logged and stored in the database, Los Angeles streets are effectively under nearly permanent video surveillance. In the absence of any statewide regulation, agency privacy protections vary dramatically between institutions. The LAPD, for example, apparently holds the data for approximately two years, even on entirely innocent individuals. While the department has been hesitant to respond to ACLU records requests, written procedures appear to allow for data retention even of information not linked to any crime.
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