Surveillance technology, explained
One page per kind of technology: what it is, what it records, why agencies say they need it, what the documented concerns are, and what the law requires. Each one lists every county where we have found it, with the records behind that finding.
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An automated license plate reader photographs every passing vehicle and records the plate, the time and the place. It does not watch suspects. It logs everyone, and the record is usually kept on a vendor’s servers.
161 systems and 44768 community-reported devices in 420 counties
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An unmanned aircraft carrying a camera, flown by a public agency. Where a state classes drones as military equipment, as California does, a public policy and a governing-body vote are required before an agency uses one.
57 systems in 45 counties
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A camera worn by an officer, recording encounters with the public. What it captures, how long the footage is kept and who may watch it are set by department policy rather than by one statewide rule.
42 systems in 37 counties
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Camera networks
Fixed and steerable cameras run by a public agency, often networked so footage from many locations can be watched or searched from one place.
58 systems and 9860 community-reported devices in 213 counties · explainer in progress
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Software that measures a face in an image and searches for a match in a database of known faces. It can be run on live camera feeds or on recorded footage after the fact.
12 systems in 11 counties
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Networked microphones placed around a neighborhood that listen for gunfire and report a location to police. The microphones are always on.
4 systems and 744 community-reported devices in 84 counties
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A list, kept by a police department, of privately owned security cameras and where they are. Officers use it to ask owners for footage. Some registries also let an agency request footage through the camera vendor’s app.
11 systems in 11 counties
A technology joins this list when some county has a documented system or a mapped device for it. This is a record of what we have found, not a catalog of everything that exists.