Automatic License Plate Readers (ALPR) – Best Practices Guidance

*COMPLIANCE DEADLINE APPROACHING*

Agencies that receive state funding and utilize ALPR technology should have received a letter from the Missouri Department of Public Safety on or about September 23, 2026. The letter requires agencies to come into compliance with Executive Order 26-18 and submit a DPS certification form indicating full compliance by October 31, 2026. If your agency has not come into full compliance and/or has not yet submitted the compliance certification form, please prepare to do so no later than next Friday.

On September 16, 2026, Governor Mike Kehoe issued Executive Order 26-18 (“the Order”) establishing minimum standards governing ALPR technology until permanent legislative enactments are made. The Order applies to State entities and local law-enforcement entities that receive state funding and utilize ALPR technology. The Order directed the Director of the Missouri Department of Public Safety to issue guidelines addressing strict controls, operational limitations, accountability measures, and penalties governing the use and misuse of ALPR technology.

The Director issued such guidance on September 30, 2026, in a document entitled the Automated License Plate Reader Best Practices Guide (“the Guidance”). The guidelines establish best practices for use of ALPR technology but are not a statement of Missouri law. The guidelines must be applied to existing Missouri law, including, but not limited to, the Sunshine Law, records retention regulations, and currently approved contracts of any agency. As stated in the Order, the Guidelines serve as a bridge for minimum standards until the Missouri General Assembly can enact legislation on this matter, which may not occur until May 2027 and might not take effect until August, 2027, if any legislation is passed.

All the information summarized in this Memo and laid out in the Guidance is relevant for the creation of an agency’s ALPR use policy. Topics in the Guidance also touch upon issues that are relevant to an agency’s compliance with the Sunshine Law and its agreement with the ALPR vendor.

A. ALPR Program Fundamentals

The Guidelines emphasize from the outset the importance of ALPR systems as investigative and public safety tools—not as unrestricted databases of vehicle movements. Furthermore, the Guidelines establish five important principles for durable ALPR system controls:
- - Legitimate purpose
  - Individual accountability
  - Proportional access
  - Controlled retention; and
  - Auditable use
The best ALPR programs must be able to answer the following five questions for any search or disclosure of ALPR data:
- - Who accessed the information?
  - What legitimate purpose supported the access?
  - What case, incident, or other identifier connects the activity captured by ALPR to that purpose?
  - What information was obtained or disclosed from ALPR data?; and
  - What happened to the information after the access or disclosure occurred?

B. 19 Points of Guidance

The Guidance lays out nineteen different points related to management and control of an agency’s ALPR system. Every agency should carefully read and constantly refer to the Guidance as each line contains important information issued by the Department of Public Safety. For purposes of this Memo, we will list the individual points by title and provide a summary of the most significant recommendations.

Policy Purpose, Scope, and Definitions
- - Apply the policy to all forms of ALPR technology systems
  - Create good definitions of applicable terms to include a broad range of data collected
  - Define specific terms related to “alerts”, “hits”, “historical searches”, and “hot lists”
  - Identify an ALPR Administrator or Coordinator
  - Ensure ALPR systems are approved by the Missouri Department of Public Safety and Department of Transportation
Authorized Uses
- - Locating
    - Stolen or wanted vehicles or license plates
    - Missing, endangered, or abducted persons
    - Vehicles associated with active investigations, warrants, BOLOs (be on the lookout), and other authorized alerts
  - Investigating
    - Criminal offenses and developing investigative leads
    - Hit and run and other serious or fatal traffic crashes
    - Review crime scene information and other retrospective searches reasonably calculated to locate evidence or information related to an investigation
      - Responding to public safety emergencies and life safety events
Expressly Prohibited Uses
- - Personal curiosity or non-official searches
    - Self, family, friends, neighbors, coworkers, romantic partners, exes, public officials, celebrities
    - For a private individual or as a personal favor
    - To stalk, harass, intimidate, threaten, retaliate, or improperly monitor
User Access and Account Security
- - The designated ALPR administrator controls who is granted access and must periodically review the active user list and permissions; access must be disabled or modified promptly when personnel changes dictate
  - Access to ALPR must be limited to documented, authorized personnel whose duties reasonably require such access through individualized, assigned accounts—shared accounts or credentials and using someone else’s account are prohibited
  - Users must be required to log out when access is no longer needed
  - Suspected unauthorized access, credential compromise, data loss, or improper disclosure must be reported to agency leadership immediately
Training and Competency
- - Individuals must complete training on the topics enumerated in the Guidance BEFORE accessing the ALPR system
  - Refresher training required when significant changes in law, policy, technology, system configuration, or vendor functionality arise
  - The agency must maintain records showing
    - Who completed training
    - When training was completed
Hot Lists and Manual Entries
- - Hot lists may only be created by authorized users
  - Keep a record of:
    - Requesting user
    - Date
    - Plate/state
    - Relevant vehicle information
    - Reason for entry
    - Associated case/CAD/incident/warrant/BOLO/alert identifier
  - Establish a review or expiration date for temporary alerts and remove or deactivate entries immediately when the underlying purpose no longer exists
  - Review hot lists for stale, duplicate, erroneous, or unsupported entries
  - Require manual entries to identify the source and reason for the entry
Alert/Hit Verification
- - DO NOT treat an ALPR alert as self-authenticating evidence of a crime OR as a substitute for an independent records check
  - Always:
    - Visually compare the captured plate with the alert or read and confirm the jurisdiction
    - Confirm the underlying record is current through an appropriate law enforcement database
    - Determine what the alert relates to and whether the circumstances justify enforcement action
    - Verify the alert/plate and other identifying characteristics BEFORE TAKING ACTION
    - Establish the legal basis for any stop, detention, search, seizure, or arrest INDEPENDENTLY of the ALPR alert
    - Document significant verified hits according to agency reporting requirements
Historical Searches and Query Documentation
- - Users – every search must be attributable to an individually authorized user
  - Purpose – specific, legitimate, law enforcement or public purposes for the search must be stated
  - Identifier – identifiers (case, report, CAD, incident, warrant, BOLO or other) must be entered
  - Specificity – explanations must be detailed enough for later supervisory/audit review
  - Parameters – the ALPR system must retain search parameters
  - Result/Use – significant results and subsequent disclosures must be handled under applicable evidence and records procedures
Historical and Pattern-of-Life Searches
- - Historical and pattern-of-life searches MAY ONLY BE USED in furtherance of a narrowly focused criminal investigation to reconstruct a criminal suspect’s or a victim’s movements over time
    - Searches must be reasonably related in scope and time to the documented investigative purpose
    - Elevated supervisory review is required for broad searches intended to reconstruct long term movements; including when a search for a particular vehicle expands—this expansion requires documentation and supervisory approval
Data Accuracy and Error Correction
- - Treat ALPR data as technology capable of misreads and false matches and provide a mechanism to identify misreads
  - Correct or remove erroneous manually entered hot list information immediately
  - Establish a process for recurring camera recognition errors, inaccurate jurisdiction reads, duplicate records, and stale alerts
  - If erroneous information was created in an external database, inform the data owner
  - Emphasize that the current driver or occupant of a vehicle flagged in an alert is not proof alone that the person is the wanted person
Retention, Deletion, and Preservation
- - Routine, non-evidentiary data – retain for the shortest period allowed under law and regulations; must not be retained longer than 30 days; automated deletion is best
  - Active investigation data – preserve in the applicable investigative/evidence system under the applicable records retention period
  - Evidence/litigation/discovery hold – preserve this ALPR data independently of routine deletion until the hold is released
  - Audit logs – retain in accordance with the agency’s records schedule, but long enough to support meaningful compliance review. These logs may be subject to review by the Department of Public Safety without notice
  - Vendor hosted data – Contracts must establish retention/detention requirements and prohibit the vendor from both retention beyond the agency’s authorized period and premature deletion as THIS IS THE AGENCY’S DATA, not the vendor’s (see Point 14 below)
Data Security and Confidentiality
- - Multi factor authentication is required
  - Ensure all facets of the system, from access and credentials, to data and hardware, and to audit logs are safe from unauthorized access
  - Require prompt notification of security incidents; preserve system logs associated with a suspected security event
  - Periodically review security of the system
  - Maintain audit logs
  - Prohibit storing or transmitting ALPR information on personal devices
  - Apply vendor security requirements to hosted systems and data processors
Information Sharing and Outside Access
- - ALPR information can only be shared for legitimate law enforcement or public safety purposes and is subject to NCIC data sharing controls keep a log of sharing activity to include:
    - Recipient
    - Organization
    - Date and time
    - Information shared
    - Purpose
    - Responsible person
  - ALPR information cannot be shared for private commercial purposes
  - Policy must require supervisory approval and documentation for disclosures of identifying information from non-alert data
Vendor and Third-Party Requirements
- - Contracts must establish that the agency retains ownership and ultimate control of agency ALPR data
  - Vendors and subcontractors have no right to do anything with agency data
  - Minimum contract/agreement/MOU requirements:
    - Agency ownership of data
    - Permitted vendor access (limited to system maintenance)
    - Required prohibitions on vendor use/secondary use of data
    - Security safeguards and subcontractor/downstream provider controls
    - Retention and deletion requirements, including verification
    - The agency’s audit and compliance rights
    - Data return/deletion at termination of contract
    - Vendor’s compliance with agency requests for preservation, etc. and prohibition against disclosure of agency data without prior authorization from agency
Privately Owned, Commercial, and Community ALPR
- - Any ALPR data received from privately or commercially owned ALPR systems is subject to the same requirements as agency ALPR data
Auditing and Accountability
- - Three complementary audit levels should be employed:
    - Routine – At least monthly audit log review by ALPR administrator; agency implement technology for continuous audit reviews to flag potential misuse
    - Targeted – Audits that are initiated by complaint, suspicious query patterns, unusual after-hours activity, repeated searches, sensitive person searches, suspected misuse, or other abnormalities
    - Annual – Review user permission, training, search logs, sharing, retention/deletion, vendor compliance, complaints, security incidents, audit findings, and program effectiveness
  - Audit findings must be documented and reported to the designated executive/administrator—any credible evidence of misuse shall trigger an investigation and immediate access restriction when warranted
Complaints, Misuse, and Corrective Actions
- - Provide a defined process for receiving and documenting complaints or suspected misuse that includes preservation of audit logs and system records of the alleged misuse
  - Restrict/suspend access when necessary to protect the investigation or data (LEO Bill of Rights considerations may apply)
  - Document corrective action (personnel record considerations)
  - Misuse by a LEO shall be reported to the Director of the Department of Public Safety for a POST investigation
  - Criminal misuse shall be reported to the jurisdiction’s prosecuting attorney
  - Use substantiated findings to improve training, the system, and/or policy
Records, Evidence, and Legal Holds
- - Treat evidentiary ALPR data differently than routine, non-evidentiary data
  - Document the circumstances causing ALPR data to become evidentiary
  - Do not allow routine automated deletion to occur to ALPR information under a legal hold
Program Evaluation and Transparency
1. - Track false alerts and recurring errors
  - Review audit findings, complaints, security incidents, and access trends
  - Review objectives for ALPR equipment deployment locations
  - When appropriate under applicable law and record retention requirements, publish or otherwise report program level information

C. Fourth Amendment Considerations

Generally, the use of an ALPR to photograph or read a license plate visible on a public roadway is not an invasion of privacy and does not require a warrant. In State v. Loyd, 338 S.W.3d 863 (Mo. App. W.D. 2011), the Missouri Court of Appeals held that an officer’s computer check of a publicly visible license plate did not constitute a search that required a person’s consent or a warrant. A license plate is displayed on the exterior of a vehicle and is intended to convey identifying information. When the vehicle is viewed in public where there is no expectation of privacy, viewing and taking photos or video of a license plate or the vehicle is not an invasion of privacy. Therefore, the law currently allows the use of ALPR cameras on public roadways.

One constitutional concern arises when large quantities of ALPR observations are retained, aggregated, shared, and searched over time. Courts have not established a uniform rule regarding warrantless searches of ALPR databases. In United States v. Yang, 958 F.3d 851 (9th Cir. 2020), the Ninth Circuit suggested that where ALPR databases are extensive, there could eventually raise concerns similar to historical cellphone-location information. Thus, cities should be careful not to utilize ALPR cameras to develop an extensive record of an individual without first obtaining a warrant.

D. ALPR Data Is Distinct From Cellphone Data

Some discussions of ALPR cameras conflate license plate information with cell phone data. License-plate information is materially different from cellphone data. A license plate is intentionally displayed to the public, and Loyd recognizes that an individual does not have a reasonable expectation of privacy in the plate number displayed on a vehicle traveling in public.

In contrast, cellphones generate electronic location information that is not intentionally exposed to public observation and may reveal detailed historical movements. In Chatrie v. United States, (Docket No. 25-112), decided June 29, 2026, the Supreme Court held that law enforcement’s use of cellphone location data through a geofence required a warrant because individuals have a legitimate expectation of privacy in cellphone location data.

Because cell phone data is generally not exposed to the public and license plate information is gathered in public where there is no expectation of privacy, cellphone location cases should not be conflated with ALPR use. However, the distinction may change as ALPR technology changes and as litigation reaches the Supreme Court.

E. Continuing Review

These recommendations depend on each municipality’s specific ALPR hardware, software, database access, retention settings, search functionality, data-sharing arrangements, and other system capabilities.

Flock and other vendors may offer different products and features that change over time. The Constitutional analysis may likewise change if a system evolves from recording observations on public roadways to compiling or reconstructing extensive historical movements.

This memorandum should not be interpreted as concluding that every Flock product, feature, database, or use is legally equivalent. These recommendations are directed primarily toward ALPR readers and should be revisited whenever a municipality materially changes its hardware, software, retention periods, search capabilities, artificial-intelligence features, data-sharing arrangements, or other surveillance capabilities.

F. Next Steps

Agencies that desire to continue to utilize ALPR technology should immediately:

Create, revise, or amend their policies for the use of ALPR technology to ensure compliance with Governor Kehoe’s Executive Order 26-18 and the Missouri Department of Safety’s Director’s Automated License Plate Reader Best Practices Guide.
Assign a primary ALPR Administrator for the agency and implement an appropriate chain of command for the agency’s implementation of the Order and the Guidance.
Review and consider amendments to the agency’s Sunshine Law policy to clarify records that will be routinely generated in compliance with the Order and Guidance.
Create or otherwise procure training on the usage of ALPR systems as provided in the Order and the Guidance.
Contact their ALPR system vendor to request a required amendment to the agreement with that vendor to ensure that it complies with the Order, the Guidance, and agency policy.
Monitor legislative activity related to this subject matter—remain mindful that the Order and Guidance are intended as stopgap direction until the General Assembly can provide legislative clarity on these issues.

Our firm is currently working with agencies across the state to address the issues raised by the Order and the Guidance. Please let us know if you would like our assistance in creating, advising, or reviewing your agency’s policy, agreement, or training materials, or if you need assistance with your compliance certification form.

Automatic License Plate Readers (ALPR) – Best Practices Guidance