Explainer
How do these cameras actually work?
Automated license plate readers (ALPR) are small cameras — often mounted on poles, patrol cars, or trailers — that photograph the license plate of every passing vehicle. This is the plain-language version of what they see, where the data goes, and why it matters.
What a camera captures
An ALPR camera is angled at the roadway, not at the sidewalk. For each passing car it records:
- the license plate image and the plate number (read by software, like OCR),
- the date and time of the reading,
- the GPS location of the camera,
- and, on some systems, a wider image of the vehicle.
These cameras are not facial-recognition cameras — they are aimed at plates and vehicle rear ends. But because a plate is attached to a car, a record of plates is, in practice, a record of where cars go.
Where the data goes
The reading is sent to the agency or department that operates the camera, and typically into a database tied to that agency. Many systems — including Flock Safety's — are built so that agencies can share their camera feeds and look up plates across a network of other departments, sometimes hundreds of miles away.
A plate can also be checked automatically against a hot list — vehicles reported stolen or associated with an investigation. When a match happens, the system alerts the operator.
How long the data is kept
Retention varies by vendor, agency, and state. A common default has been around 30 days, after which records are deleted. Vendors have changed this over time — Flock Safety, for example, announced in 2026 that it was shortening its default retention — but the number that matters most is what each city's contract and policy actually say. That is one of the things this site tracks.
The rules are a patchwork
There is no single national law governing ALPR use. Rules differ state by state — and sometimes city by city — covering who may use the cameras, how long data may be kept, and who may search it. See our legal tracker for what we have verified so far.
Why this site exists
These cameras are installed on public streets, usually with public money and public approval — but the details of where they are, what contracts allow, and how long data is kept are often hard to find. dontwatchme collects the public record in one place, labels every fact with a confidence level, and links back to the source. Read how we verify.