What ALPR systems do
Automated license plate readers capture a vehicle’s plate number along with the date, time, and location. That information is stored in searchable databases. These systems do not record only vehicles suspected of wrongdoing — they capture every plate within camera range.
ALPR cameras also capture images of vehicles, not just plate characters. Those images enable searches using vehicle descriptors (like make, model, and color) and can distinguish vehicles by visible characteristics — including bumper stickers, roof racks, dents, scratches, or other markings that make a car recognizable over time.
In practice, ALPR systems create persistent identifiers for vehicles. When retained, those identifiers accumulate into a searchable history of where vehicles were seen and when. Depending on policy, that data may be retained for months or years and shared across agencies.