ACLUAllie

Right. At the same time, ALPRs can be used for their primary law enforcement purposes without storing data on the rest of us for long periods of time -- ALPRs instantly identify vehicles that are stolen, involved in a crime, or associated with fugitives; they don't need to store data that isn't evidence of an offense.

Thanks for the question, NYA. To build on Kade's answer, it's a basic tenet in our society that we don't watch innocent people just in case they do something wrong. But, license plate readers turn that principle on its head, collecting and pooling data on everyone.

I also like Virginia's attorney general guidance, which says that license plate readers cannot be used for passive data collection – that is collecting and pooling the license plate information of every car that passes them by – and can only be used “actively” – that is in pursuit of particularly identified license plates “evaluated and determined to be relevant to criminal activity.”

That's a great question, Calvin. I'm hoping one of my colleagues chimes in more. Police can follow you in public. There are remaining questions, though, about what technology they can use to follow you and for how long. There was an early location tracking case called Katz where law enforcement used beeper technology to follow someone on public roads. They had to stay within a certain range of the beeper in order for it to work. And, the court said that tracking was okay. But, the technology has changed since then, and now police can track your location (using ALPRs or cell phone location tracking or GPS tracking devices) from the comfort of their own desks (see www.aclu.org/tracked). And, recently in US v. Jones, a majority of the Justices in two concurrences (so it wasn't the majority opinion) said that they believed that any prolonged location tracking, regardless of mechanism, should be considered a search. (See: http://www.aclu.org/blog/technology-and-liberty/supreme-court-decision-gps-tracking-spur-action-congress.) As for facial recognition, check out my colleague, Jay Stanley's blog: http://www.aclu.org/blog/technology-and-liberty-criminal-law-reform-national-security-free-speech/some-thoughts-dmv

Yes. The Ohio State Highway Patrol requires that “[a]ll ‘non-hit’ APR [automatic plate reader] captures shall be deleted immediately. APR captures shall not be collected, stored, or shared with the intent of datamining.” And, the Minnesota State Patrol only keeps captured plate data for 48 hours. You can see more data retention periods in our license plate reader report on p. 20. http://www.aclu.org/files/assets/071613-aclu-alprreport-opt-v05.pdf