An ALPR camera is typically mounted on a pole, streetlight, or overpass. As vehicles drive by, the camera captures images at high speed — often of every lane of traffic simultaneously. Built-in software identifies the license plate in the image, extracts the alphanumeric characters, and records a "scan" containing four data points: the plate number, the date and time, the GPS coordinates, and a photograph of the vehicle. Flock Safety's cameras add additional metadata, including the vehicle's make, color, and body type, using machine learning models. Each scan is uploaded to a cloud database where it can be searched by any participating law enforcement agency. The Electronic Frontier Foundation (EFF) has documented how this creates a detailed record of where a vehicle — and by extension, its driver — has been over time.
Several companies manufacture ALPR systems. Flock Safety is the most prominent in the United States, marketing its cameras to police departments, homeowners associations (HOAs), and private businesses. Other manufacturers include Motorola Solutions (Vigilant Solutions), Rekor, and Genetec. What makes Flock Safety different from earlier ALPR vendors is its cloud-first architecture: rather than each police department maintaining its own local database, Flock pools scans from all of its customers' cameras into a shared national database that any Flock customer can search. The ACLU has warned that this effectively creates a nationwide mass-surveillance system.
A single ALPR scan typically captures: the license plate number, the date and time of the scan, the precise GPS location of the camera, a photograph of the vehicle (and sometimes the driver), the vehicle make, model, and color, and the direction of travel. When scans are aggregated over time, they reveal patterns of life: where someone lives, works, worships, seeks medical care, attends protests, or visits friends. The EFF has emphasized that this level of tracking constitutes a profound invasion of privacy, because it enables the government to reconstruct a person's movements without a warrant.
Retention periods vary by jurisdiction and vendor. Some police departments delete non-hit scans after 30 days, while others retain data for years — or indefinitely. Flock Safety's default retention policy stores data for 30 days, but individual agencies can configure longer retention. The ACLU has documented cases where ALPR data was retained for years and used for purposes far beyond the original justification. In 2012, the ACLU sent public records requests to nearly 600 police departments across 38 states and found widespread variation in retention policies, with some keeping data for as long as it was technically feasible.
Access to ALPR data depends on the system. In a traditional setup, only the local police department that operates the cameras can access its own scans. But Flock Safety's shared cloud model means that any Flock customer — including small-town police departments, HOAs, and private businesses — can search the entire national database. The EFF discovered that federal agencies, including U.S. Customs and Border Protection (CBP) and Immigration and Customs Enforcement (ICE), have accessed Flock's data. In one documented case, a Texas police officer used Flock's nationwide search to track down a woman who had a self-administered abortion. The ACLU has called this a "shadowy surveillance" infrastructure operating without meaningful oversight.
A standard traffic camera (like a red-light camera) captures images of specific vehicles that violate a traffic law, and a human reviews the footage before a citation is issued. An ALPR camera, by contrast, captures every plate that passes — regardless of whether a law was broken — and logs it automatically. This means ALPR systems create records of innocent people's movements, not just those suspected of crimes. The EFF has argued that this "collect everything, search later" model is fundamentally different from targeted law enforcement tools and poses a far greater civil liberties threat.
Exact numbers are difficult to determine because deployment is decentralized, but Flock Safety alone has deployed tens of thousands of cameras across all 50 states. A 2024 investigation estimated that Flock's cameras scan more than 100 million vehicles per day nationwide. The ACLU's "Get the Flock Out" campaign tracks deployments and has documented cameras in cities ranging from major metropolitan areas to small towns. Flock Alert maps documented ALPR and Flock Safety camera locations so you can see how many are in your city.
What does ALPR stand for?
ALPR stands for Automated License Plate Reader. It is a camera system that automatically captures and reads vehicle license plates using optical character recognition, logging the plate number, time, date, and location of every scan.
Is ALPR the same as a traffic camera?
No. A traffic camera captures images of vehicles that violate traffic laws. An ALPR camera captures every plate that passes, regardless of whether a law was broken, and logs it in a searchable database.
Does Flock Safety own the ALPR data?
Flock Safety stores ALPR data on its own cloud servers. While the purchasing agency technically "owns" the data, Flock controls the infrastructure and can make the aggregated database searchable by other customers nationwide.
Can ALPR cameras read plates at night?
Yes. ALPR cameras use infrared illumination to capture plate images in low light, at night, and in adverse weather conditions. They are designed to operate 24/7.
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