Remember the old police dramas like Adam-12 and Dragnet? Shows like that are how many of us got an idea of how police work. And of course one tried-and-true method to catch the bad guy is to "be on the look out." Some crime happens, the dispatcher broadcasts a car description and license plate number, and before the next commercial break, the wanted car pulls out right in front of our hero officers.
But these days, police records can hold untold numbers of stolen cars, crime suspects, fugitive warrants or other persons of interest all linked to license plate numbers. With a technology called Automated License Plate Readers mounted on patrol cars, scanners pick up every license plate near by and constantly check them against the list of wanted cars. These ALPR devices pull information for every license plate that they come across, regardless of whether or not the vehicle is suspicious in any other way. But there's just one problem.
While it is certainly a huge benefit for police to get instant alerts when a wanted fugitive pulls out in front, there is also the issue of what happens to the massive amount of data collected from these 24/7 scanners. Just think for a moment that every plate is recorded and time-stamped with its exact location. As technology often moves faster than policies and regulations, there are few rules in place about how this data is handled or how long it is kept.
If a law that just passed Virginia's state house and senate isn't vetoed, then it will be one of the first states to institute short limits on data collected by ALPRs.
Ars Technica explains how LPRs and ALPRs work:
Typically, the specialized cameras scan a given plate using optical character recognition technology, checking that plate against a "hot list" of stolen or wanted vehicles. The device records the date, time, and GPS location of any plates—"hot" or not—that it sees.
The problem is that this data often sticks around forever. Ars Technica explains why Virginia's new law could be an important step:
Many jurisdictions nationwide, ranging from the New York State Police to the Oakland Police Department, have no formal data retention limit. That means the location data—often resulting in millions of records collected over years—is effectively kept forever.
That means that if more states follow Virginia's lead (assuming the law gets passed) then data could be dealt with more securely. And circumstances like the one that lead to a woman being held at gunpoint because of a faulty plate reader might happen less often.