How automated license plate readers work, and how long data lasts

An automated license plate reader is a camera that captures, analyzes and stores license plate data, and how long that data lives is set by policy and state law. The camera logs each scan with its date, time and place, and it alerts police when a plate matches a hot list, per the National Conference of State Legislatures. Retention varies widely. A review by the California State Auditor found one large agency holding 320 million images, most of them of cars never tied to an investigation, while some departments plan to purge records within a year. The storage clock is now the main focus of new state rules. For related coverage, see What police records management systems store, and why data quality varies. What does a plate reader capture? The cameras read plates on moving cars, not just parked ones. Devices sit on police cars, road signs and traffic lights, and they can log a vehicle's make, model, color, location and distinct features, along with the date and time, per NCSL.

This excerpt comes from the named source. Read the original for the full reporting.