This post was written more than four years ago. The world changes fast, and the information, conclusions, or attributions may or may not still be accurate. Check the sources and links, and email me if you have any questions.

In recent months, news has surfaced that the Minneapolis Police Department has been using Automated License Plate Recognition (ALPR) systems attached to squad cars and light poles around the city. These devices use infrared cameras and optical character recognition systems to ‘read’ license plates as the cameras see them, day or night.

ALPR systems search those license plates against a database of stolen cars and wanted felons, which at first glance seems like pretty cool technology for law enforcement to have: police keep their eyes on the road instead of typing in license plates, automated technologies can’t have bias like a human officer would, and it’s a force multiplier that will surely result in criminals being caught.

However, these ALPR systems aren’t just actively alerting officers – they’re also storing data on people not wanted for any crime. If your license plate is picked up by an ALPR scanner, the date, time, and geographical coordinates – along with a photograph of your vehicle and possibly even you – are captured and stored.

This certainly deserves discussion. On one hand, this will solve violent crime – police being able to go back and see what vehicles were in a certain area has immeasurable investigative value. But on the other, even with a lowered expectation of privacy while out in public, mass surveillance of people not suspected of any crime certainly feels like a violation of the Fourth Amendment, or at least our ideals as Americans.

Sadly, that discussion wasn’t had.

Minneapolis Police purchased and installed the ALPR cameras and databases prior to consulting with the state legislature, and without any community input. As a result, there were no policies nor laws in place to protect the data these systems collect. Not only can police search through the database at any time they wish and for any purpose, the public can submit a request too.

Think of these terrifying possibilities:

  • A victim of domestic abuse’s daily activities could be monitored, and their places of safety could easily be made known to their abuser;
  • Elected officials, diplomatic cars, and government workers could be tracked as they go around the city;
  • Disability license plates follow a special formatting, and an attacker or thief could target the homes of people with disabilities;
  • ALPR systems are turned on in police station parking lots, capturing police officers’ personal vehicle license plates — those license plates can easily be cross-checked and found outside of the officers’ homes or their favorite restaurants;
  • An armored vehicle delivering cash or a hazmat truck’s usual route can be tracked;
  • Debt collectors could find out where you work;
  • or… just every-day surveillance of when you leave and come back to your home.

Since the Minneapolis Police Department opted to use this equipment prior to any laws could be considered, I asked the City to request a temporary classification from the Minnesota Department of Administration’s Information Policy Analysis Division (IPAD) – so at least the general public wouldn’t be able to stalk each other.

The City ignored my concerns and sure enough, they started to receive requests for data, including a request for the entire database of records. I asked for a copy too, so that I could do some research to present to the Legislature – and the City provided me 2.1 million ALPR scans on a USB flash drive for all of $5.91.

Shortly following that, the City elected to finally submit a temporary classification request to IPAD, which immediately made the data non-public until the state could review it. However, the City also requested broad concealment of data about how they use ALPR cameras, including the concealment of the locations of those cameras.

I disagreed with their latter decision, and so I submitted a public comment which IPAD substantially agreed with in their findings of fact, making the license plate scan data nonpublic until the Legislature can act next session, but keeping the City’s general use of ALPR systems and the locations of cameras public.

MPD and IPAD have asked the Legislature for guidance on data classification for ALPR data, so hopefully this coming legislative session will address not only the classification of the data as private, but also address regulation and enforcement of use of the data, including laws enforcing allowed retention time by police.

I think there are solid arguments on both sides of the retention debate – although I would prefer no retention – but I am at least glad that privacy is somewhat preserved in the meantime.

(Updated since original posting)