About

FlUck is a free, open-source, crowd-sourced map of marked police vehicles. Volunteers add cameras (a phone, a Raspberry Pi, or a webcam) that report when they see a police vehicle. The map shows where, and lets you follow one car's plate across the cameras it passed.

How it works

Cameras report police vehicles only. Plate reading runs only on vehicles already recognised as police; other traffic is not read, and the server refuses plates that arrive on any other vehicle class.
Everything public is delayed and approximate. Sightings appear after a short delay (currently 3 minutes; the operator sets it) and locations are rounded to roughly 100 m.
Cars first. Search a plate to see that car's route: the cameras it crossed, in order, with a replay.
Cameras online. Cameras check in regularly, so you can see how many are online. A phone only appears on the map if its owner switches that on.

How we keep it honest

A plate is shown only once two different people have reported it. A plate seen by a single reporter stays hidden, so one mistaken or malicious report can't put a name-tag on a car.
Anyone can flag a sighting that looks wrong. Several independent flags hide it automatically until the operator has looked at it, and the report form reaches a person who answers within a stated time.
Impossible reports are refused: a camera can't be in two places far apart minutes apart, and new cameras must complete a small proof-of-work, so floods are expensive.
The data is open. The same delayed, approximate sightings the map shows can be downloaded as CSV or GeoJSON (a weekly file too), under the Open Database Licence 1.0: use it freely, credit FlUck contributors, and share improved versions the same way. You can also see the hour-of-week pattern of an area.
Live tags are different, and deliberately so. Anyone can drop a "police here" pin, like in a navigation app. It carries no plate and no identity, shows at the usual ~100 m blur, disappears after about 45 minutes, and other people can say it is "still there" or "gone". Plates, tracks and downloads stay delayed. Never use it while driving.
The public can help check unsure detections. When a camera is not sure and sent a small photo, anyone can look at it on the review page and vote; a few agreeing votes approve or reject it, and the photo is deleted at once.
Cameras earn trust. Duplicate reports of the same car are merged into one, a camera whose sightings keep getting hidden stops counting towards plate confirmation, and unsure detections wait for a human check before they appear.

Add your camera

Anyone can join: add a phone, Pi or webcam in under a minute, with no account and no admin. Pick a hacker handle and a name; your camera is listed under your handle.

Run your own

FlUck is free software under the GNU Affero General Public License v3. It runs on a small VPS or on ordinary PHP and MySQL shared hosting, and installs through a web wizard. The source code is available at https://github.com/hacker213/FlUck.

Why this is legal (and a little ironic)

FlUck rests on a simple, well-settled idea: what is in plain view on a public road can be seen, recorded and shared. A licence plate is displayed on a public road by law, and a marked police car with its markings and plate is in public view like any other vehicle. Volunteers recording what they can see from public places are exercising the First Amendment right to gather and share information.

Filming government officials is protected

Glik v. Cunniffe, 655 F.3d 78 (1st Cir. 2011). The federal appeals court held that filming police officers carrying out their duties in a public place is protected by the First Amendment, and that arresting someone for it violated clearly established rights.
Turner v. Driver, 848 F.3d 678 (5th Cir. 2017). The Fifth Circuit, which covers Texas, Louisiana and Mississippi, recognised a First Amendment right to record police activity, subject only to reasonable time, place and manner limits. (The officers in that case kept qualified immunity because the right had not yet been clearly established; the court said it exists going forward.)
ACLU of Illinois v. Alvarez, 679 F.3d 583 (7th Cir. 2012) and decisions from other circuits reach the same conclusion about recording police.

The same rule that companies like Flock rely on

Companies that sell automatic licence-plate readers build their legal case on the very principle above. Flock Safety's own LPR policy (last updated June 30, 2026) says the images in its system are collected from areas visible to the public where there is no reasonable expectation of privacy. Asked about the Fourth Amendment in an interview with The Drive (Joel Feder, July 29, 2026), Flock's CEO Garrett Langley said: “The courts have deemed this is not a warrantless search.”

We agree that recording in public view is lawful, and we apply it in both directions: if a camera on a pole may record every plate that drives by, a volunteer with a phone may record the police vehicles that drive by, and share what they saw.

It has not always been mutual. In January 2025, lawyers for Flock sent the creator of the DeFlock project, which crowd-sources a map of where such cameras are, a letter alleging trademark dilution and demanding that he stop using the name (404 Media, Feb. 26, 2025). The Electronic Frontier Foundation, representing him, answered that the claims were groundless and that the project is protected speech (EFF, Feb. 26, 2025). We report both sides as published and draw no conclusion about anyone's motives.

What this is not

Not legal advice, and not a promise that every use is lawful. The cases above are about recording officers and about plain-view information; they do not decide every question about publishing a database, and they say recording is subject to reasonable limits. Laws differ by country, state and city, and courts keep ruling on these questions.
Not a licence to interfere. Stay out of the way of officers, never use the Service while driving, and never use it to harass, threaten or follow anyone (see the Terms of Use).
Sources were checked in October 2026 and may have changed since; follow the links to read the originals.

Please read

Reports come from volunteers and can be wrong, late or incomplete. FlUck is for public information only: never use it while driving, and never use it to harass, threaten or interfere with anyone. See the Terms of Use and the Privacy Policy.

Something wrong, misidentified, or you want data removed? Tell us.