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Antioch Police | License plate readers

Antioch's plate reader policy keeps data for at least a year and directs officers to canvass plates around homicides and shootings. The chapter carries no immigration or out-of-state clause, where the Richmond policy in the same county does.

At a glance

Retention
A minimum of one year on the server, then it may be purged unless it is or may become evidence [1]
Sharing
Law enforcement and prosecutorial agencies, on a written request naming the agency, the requester and the purpose [1]
Suspicion needed to run the system
None. The policy says reasonable suspicion or probable cause is not required before using a reader [1]
Canvassing
The policy gives particular consideration to using reader-equipped cars to canvass around homicides, shootings and other major incidents [1]
Audits
The policy says audits should be conducted on a regular basis, without setting a schedule or a sample size [1]
Limit on federal or out-of-state agencies
the plate reader chapter names none. The manual does carry a separate immigration chapter, which does not mention plate data. This describes the documents, not current practice [1]
Camera count and vendor
not in the policy. The EFF Atlas snapshot in this repo records Motorola Solutions equipment and more than 20,000,000 vehicle scans in 2022 [3]

How it happened

  1. Context

    Atlas snapshot records the 2022 scan volume

    The EFF Atlas of Surveillance records the department collecting more than 20,000,000 vehicle scans in 2022 using Motorola Solutions equipment. [3]

  2. Context

    Policy 422 carries a November 2024 stamp

    The department's policy manual carries a Lexipol copyright stamp of November 26, 2024. Policy 422 sets a one-year minimum retention and a written-request procedure for sharing. [1]

What the policy establishes

Antioch’s plate reader rules are Policy 422, a chapter of the department’s manual, carrying a Lexipol copyright stamp of 26 November 2024.[1]

Retention is a floor rather than a ceiling: data downloaded to the server “should be stored for a minimum of one year” and thereafter “may be purged unless it has become, or it is reasonable to believe it will become, evidence”.[1] Richmond’s policy, in the same county, holds data “no longer than thirty days”.[4]

The policy is explicit that no suspicion is required to use the system, and explicit about canvassing. A reader “may be used in conjunction with any routine patrol operation or criminal investigation. Reasonable suspicion or probable cause is not required before using an ALPR.” And while a reader “may be used to canvass license plates around any crime scene, particular consideration should be given to using ALPR-equipped cars to canvass areas around homicides, shootings and other major incidents”.[1]

Sharing runs on a written request naming the agency, the person requesting and the intended purpose, approved by a bureau commander and retained on file.[1]

What the chapter does not contain

No clause on federal immigration enforcement, no restriction on out-of-state agencies, and no protected-characteristic or First Amendment clause. The manual does address immigration in a separate chapter, and that chapter does not mention plate reader data.[1]

The comparison worth drawing is local rather than abstract. Richmond’s plate reader chapter, in the same county and on the same commercial policy platform, states that the department “does not permit the sharing of ALPR data … for purpose of federal immigration enforcement” and names ICE and Customs and Border Patrol.[4] California’s Attorney General published guidance in 2023 reading state law to bar sharing plate data with out-of-state and federal agencies, which applies whatever a local policy says.[2]

We hold no record of what Antioch has shared, with whom, or when, and this page claims nothing about it.

What the record does not establish

The policy names no vendor, no camera count and no locations. The Atlas of Surveillance snapshot in this repo records Motorola Solutions equipment and more than 20,000,000 vehicle scans in 2022, a dated third-party row rather than a department record.[3]

Where to ask

The written sharing requests are kept on file by the department’s own policy, which makes them askable. So are the audit records. A request for the past year of approved sharing requests would show which agencies have received Antioch plate data. Antioch City Council meets in public and takes comment, and whether the department’s plate reader chapter should carry the sharing limits Richmond’s does is a council question.

Questions

How long does Antioch keep plate data?
Policy 422 says data downloaded to the server "should be stored for a minimum of one year" and may then be purged unless it is, or may become, evidence. Richmond, in the same county, sets the opposite limit at thirty days. [1] [4]
Does the policy say anything about immigration authorities?
The plate reader chapter does not. It permits sharing with law enforcement and prosecutorial agencies on a written request and names no restriction on federal or out-of-state agencies. The manual carries a separate immigration chapter, and that chapter does not mention plate reader data. Richmond's plate reader chapter does carry an express bar naming ICE and Customs and Border Patrol, so the difference is between departments rather than unavoidable. [1] [4]
Are my plates collected if I live near a crime scene?
Possibly. The policy says that while a reader "may be used to canvass license plates around any crime scene, particular consideration should be given to using ALPR-equipped cars to canvass areas around homicides, shootings and other major incidents". Canvassing collects the plates that are there, not only plates already of interest. [1]

On the map

The community has mapped 577 devices of this type in the county on OpenStreetMap. These are community reports: the vendor and operator of each point are unverified, and none is confirmed to belong to this system. See them on the map →

Street names from reverse geocoding — © OpenStreetMap contributors (ODbL).

What we do not know

What you can do

Show up

Systems like this one are approved by boards, councils and committees that meet in public. We have not yet confirmed where each of them meets in Contra Costa County.

What we have documented in Contra Costa County →

Protect yourself

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.
    Antioch Police Department Policy Manual, Policy 422, Automated License Plate Readers (ALPRs) · Primary document · accessed · archived copy
  2. 2.
    California Department of Justice, Information Bulletin 2023-DLE-06, guidance on sharing licence plate reader data · Law · accessed · archived copy
  3. 3.
    EFF Atlas of Surveillance, Antioch Police Department ALPR entry (snapshot captured 2026-08-20) · Dataset · accessed · archived copy
  4. 4.
    Richmond Police Department Policy Manual, Policy 433, Automated License Plate Readers (ALPRs) · Primary document · accessed

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