One of the curious things about digitization is that it allows data to be circulated and shared almost effortlessly. New, cheap ways of sharing and storing data can turn data collection that was previously quite innocent into a serious threat to our ability to be free from government surveillance.
Historically, the law has recognized no constitutional issue with law enforcement collection of license plate numbers, because cars are normally out in public when the numbers are collected. But what happens if cop cars can collect every license plate from every car they pass, moving or parked; check the plate against a database of outstanding warrants; link them to GPS coordinates; and retain the records of which car was where forever, so that they can retrospectively construct a map of your movements?
Well, folks, that bright new day is here. The devices are called “automated license plate readers”, or ALPRs for short. And the ACLU of Massachusetts is supporting a bill that tries to grapple with their implications, and that received its first Joint Committee on Transportation hearing on May 16.