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ORWELL INDEX

License plate readers

The argument about license plate readers is not really about the cameras. It is about the database they fill: a searchable record of ordinary movement, kept for periods California's state auditor found no reviewed agency had tied to any documented use.

Updated

In one sentence

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.

How they work

A reader is a camera pointed at a lane of traffic, paired with software that finds the plate in the image and turns it into text. Some are bolted to poles at intersections and town entrances. Others are mounted on patrol cars and read plates as the car drives, including in parking lots.

Each read produces a record: the plate number, a timestamp, the camera’s location, and at least one photograph. The record goes into a database, usually one the vendor hosts rather than the agency. An officer can search that database for a plate, and in many systems can also ask to be alerted the next time a particular plate is seen.

What separates them from a police officer watching traffic

An officer watching a road remembers almost nothing. A reader remembers everything, indefinitely, and its records can be searched in seconds.

That difference is what the technology is for, and it is also what the argument is about. One camera on one road produces a thin record. Cameras on every road into a town produce a log of when residents come and go. California’s State Auditor reached the same conclusion in 2020, reporting that the agencies it reviewed were holding large volumes of images of vehicles that had nothing to do with any investigation, and were not adequately protecting the privacy of the people those images belong to.

How to recognise one

Fixed readers are usually small rectangular cameras on their own pole or attached to a traffic signal, angled down at a lane rather than out at a scene, and often paired with an infrared illuminator that looks like a second dark lens. Vendor-installed poles frequently carry a solar panel and a small equipment box. Patrol-car readers sit on the roof or trunk lid, angled outward, and come in pairs.

Why agencies say they need it

What the concerns are

What the law requires

State Law What it requires
California SB 34 (2015), Civil Code 1798.90.5 and following An agency operating a system must adopt a usage and privacy policy and post it conspicuously on its website. The policy must state the authorised purposes for collecting the data, who may access the system, how long the information is kept and how it is destroyed. The agency must also keep a record of who accessed the data and why. [4]
Oregon SB 1516 (2026), Oregon Laws 2026 chapter 77 A law enforcement agency may not use a plate reader system except as the Act provides. Before deploying one it must establish and publish policies for use, storage and retention. Captured data not tied to a court proceeding or an ongoing criminal investigation may be kept no more than 30 days, the data must be end-to-end encrypted, and the vendor must supply the agency with camera counts, fixed-camera locations, search counts and a list of every agency with access. [5]

Only the states we have researched appear here. A state's absence from this table means we have not checked it yet, not that it has no law.

Where we have found it

108 counties documented so far. Each new county is added here as its research publishes.

This list covers the counties we have researched, which is not the same as everywhere this technology operates. Counties we have not published say nothing either way.

See every county we cover →

Questions

What does a license plate reader record about me?
The plate, the date and time, the location of the camera, and an image of the vehicle. Some systems also record vehicle characteristics such as colour and make. It records this whether or not you are suspected of anything, and most of what it stores is unrelated to any investigation: California's State Auditor found that 99.9 percent of one department's 320 million stored images were of vehicles not on a hot list. [1] [2]
Do police need a warrant to look up my car?
No court has required one for a plate reader search in California. The Supreme Court required a warrant for comprehensive historical cell-site location records in Carpenter v. United States in 2018, and that reasoning has been argued to cover plate reader databases, but the question is unsettled. [3]
How long is the data kept?
It depends on the agency's own policy, which California requires it to publish. Reviewing four agencies in 2020, the State Auditor found that none had tied its retention period to any documented usefulness of the images, and noted that most other states with a set period chose six months or less. [1] [4]
Can I find out if my county uses them?
Where we have researched a county, its record is on this page. Where we have not, the fastest route is the agency's usage and privacy policy, which California requires to be posted on its website, and a public records request for the access logs the same law requires it to keep. [4]

What you can do

Civic action

Purchases and policies for this technology are decided at public meetings any resident can attend and speak at. Start with your county's record.

Go to the Alameda County hub →

Personal protection

Practical steps to shrink your personal data trail. Our guides publish at launch; until then, EFF's Surveillance Self-Defense is the best starting point.

Surveillance Self-Defense ↗

Sources

  1. 1.
    California State Auditor, "Automated License Plate Readers: To Better Protect Individuals' Privacy, Law Enforcement Must Increase Its Safeguards for the Data It Collects" (Report 2019-118) · Primary document · · accessed · archived copy
  2. 2.
    Flock Safety, license plate reader product page · Primary document · accessed
  3. 3.
    Carpenter v. United States, 585 U.S. 296 (2018) · Law · · accessed
  4. 4.
    California SB 34 (2015), Civil Code 1798.90.5 and following · Law · · accessed · archived copy
  5. 5.
    Enrolled Senate Bill 1516 (2026), Oregon State Legislature, with Oregon Laws 2026 chapter 77 · Law · · accessed