Short answer: an ALPR camera photographs a plate, software reads the characters, the system logs
the plate with a timestamp and location, and checks it against databases. Every vendor — Flock included —
runs this same loop.
The four steps
| Step | What happens |
|---|---|
| 1. Capture | A camera photographs the plate as the vehicle passes — day, night, most weather. |
| 2. Recognize | OCR software converts the plate image into characters and reads vehicle descriptors. |
| 3. Log | The plate, timestamp, location and descriptors are recorded to the system. |
| 4. Match | The plate is checked against hotlists (stolen vehicles, warrants, AMBER alerts); matches alert the operator. |
For the most common brand's version of this loop, see how Flock cameras work. The industry-generic picture is the same — which is why state ALPR laws matter regardless of which vendor your city chose.
What the data becomes
A single read is a record. Thousands of reads become a movement trail — that's how a plate spotted at 8:01 on one side of town and 8:09 on the other becomes a route (Boston.com). How long that trail is kept is the question that state law and local policy answer — how long plate data is stored.
Bottom line: ALPR isn't magic — it's a camera plus a database. The controversy is about who owns
the database and what happens to its records.