California License Plate Reader Laws and Privacy Rules

California’s license plate reader laws require every agency or company that runs an automated license plate reader (ALPR) system, and every outside user that searches its data, to publish a written privacy policy, keep a log of every query, protect the records with reasonable security, and destroy them on a schedule the operator has to justify. Those baseline rules sit in Civil Code Sections 1798.90.5 through 1798.90.55. Separate statutes then layer on hard limits: California police cannot share plate data with other states pursuing abortion cases, and cannot feed it to federal immigration enforcement.

Who the Law Covers

ALPR systems photograph passing plates with high-speed cameras mounted on poles, overpasses, or patrol cars, convert the images to text, and store each read with the date, time, and GPS location. A single camera can scan thousands of plates an hour.

California law splits the people responsible for that data into two groups. An ALPR operator runs the cameras and collects the reads. An ALPR end-user accesses or searches the data without operating the cameras. A city police department with its own pole-mounted cameras is an operator. A neighboring sheriff’s office that logs into that department’s database is an end-user. Both carry legal obligations under the Civil Code, and the duties overlap heavily but not completely.

Written Privacy Policy Requirements

Before an operator collects a single plate, it has to develop and publicly post a usage and privacy policy. The statute sets a floor for what that policy must address:¹

The authorized purposes the system will be used for, such as recovering stolen vehicles or enforcing parking rules.
The job titles or designations of every employee and contractor allowed to access the data, and the training they have to complete first.
How the operator will monitor the system for compliance.
The purposes, processes, and restrictions that govern any sale, sharing, or transfer of ALPR data to outside parties.
Reasonable measures to keep the data accurate and correct errors.
The retention period and the process for deciding when data gets destroyed.

The policy has to be available to the public in writing, and operators with a website must post it conspicuously there. End-users have essentially the same obligation under Section 1798.90.53, with one addition: their own policy must include a process for periodic audits.² So a department that only queries another agency’s database still needs a standalone policy of its own.

Access Logs and Audits

Every time an operator accesses its own ALPR data, or lets someone else access it, the operator has to record four things: the date and time, the plate number or other search terms used, the username and organization of the person running the query, and the stated purpose.³ The operator also has to make sure the data is used only for purposes authorized in its published policy.

Those four fields are the accountability mechanism. If an officer runs a plate for a personal reason, an audit will show a search that ties to no open case and no authorized purpose. End-users are exposed to the same review because their own policies must build in periodic audits.²

Data Security

Operators and end-users both have to maintain reasonable security procedures to protect ALPR data from unauthorized access, destruction, modification, or disclosure.² The statute describes those safeguards as operational, administrative, technical, and physical, without prescribing particular products or encryption standards. Each agency or company gets meaningful discretion in how it meets the standard.

Law enforcement agencies whose ALPR systems connect to federal criminal justice databases also fall under the FBI’s Criminal Justice Information Services (CJIS) Security Policy, which sets detailed rules on encryption, transmission security, access controls, and audit logging. Agencies that fall short of CJIS standards can lose access to federal databases.

Retention and Destruction

California does not set a single statewide expiration date for plate reads. Instead, each operator and end-user has to define its own retention period in its policy and explain how it decides when data gets destroyed.¹ The retention window is supposed to match the stated purpose. A toll system has no reason to keep reads for months after payment clears; a cold-case investigation might justify longer.

The one California agency with a hard statutory cap is the California Highway Patrol, which under Vehicle Code Section 2413 cannot keep ALPR data for more than 60 days unless it is evidence or relates to a felony investigation. Other agencies set their own limits, and in practice those limits vary widely, with some local departments retaining reads for a year or more.

Sharing Restrictions for Abortion and Immigration

Out-of-State Abortion Investigations

AB 1242, signed in 2022, bars California peace officers from cooperating with or providing information to any out-of-state person or agency in connection with a lawful abortion performed in California.⁴ The statute does not name ALPR systems specifically, but its broad prohibition on sharing “information” reaches any records that could be used for that purpose, including plate reads showing a vehicle at a reproductive healthcare facility.

There is a narrow exception. The law does not block investigation of criminal activity that happens to involve an abortion, so long as no information about a specific individual’s medical procedure gets shared with another state for the purpose of enforcing that state’s abortion laws.⁴

Federal Immigration Enforcement

The California Values Act (SB 54) restricts state and local law enforcement from using agency resources to investigate, detain, or arrest people for immigration enforcement purposes. It specifically covers law enforcement databases, including those run by private vendors, and directs the Attorney General to publish guidance aimed at limiting immigration access to those databases to the fullest extent consistent with federal and state law.⁵ ALPR databases sit squarely inside that category.

The Act also blocks agencies from providing personal information about individuals, including home and work addresses, to immigration authorities unless the information is already publicly available.⁵ Plate reads that show a vehicle’s regular travel pattern can effectively disclose where someone lives and works, which is why routing that data to federal immigration agencies raises problems under the statute.

What Drivers Can Find Out

The California Supreme Court has held that ALPR scan data is not automatically exempt from the California Public Records Act’s investigation-records exemption, so a records request cannot be denied on that basis alone. The court also recognized that releasing raw plate data could invade individual privacy, and left room for lower courts to consider whether redaction or anonymization would change the balance.

For an individual driver asking where a system has captured their own car, the answer is narrower. ALPR access is generally restricted to authorized law enforcement personnel acting for a stated lawful purpose, and members of the public typically cannot request images of their own vehicle’s reads.⁶ Getting that information means using a broader public records process and hoping the privacy balancing test comes out favorably.

Constitutional Backdrop

California’s statutory framework sits on top of a federal Fourth Amendment baseline that, so far, does not require a warrant to run a fixed ALPR camera. Courts have relied on the reasoning in United States v. Knotts (1983) that movement on public roads does not carry a reasonable expectation of privacy. In Carpenter v. United States (2018), the U.S. Supreme Court did require a warrant for seven days of historical cell-site location records because that comprehensive tracking reveals the “privacies of life.”⁷ Courts have distinguished ALPR from that fact pattern, treating fixed cameras as discrete point-in-time observations rather than continuous tracking. No court has drawn a different line for ALPRs yet, which is part of why California’s Civil Code protections already reach further than the Fourth Amendment currently requires.

Recent Legislative Developments

The framework keeps expanding. SB 34, enacted in 2015, put the original Civil Code architecture in place. SB 274, which passed in the 2025 legislative session, would bar public agencies from using ALPR systems to gather geolocation data at certain specified locations.⁸ The bill responds to concern that even individually harmless reads can, in aggregate, show which vehicles appear near sensitive places like healthcare facilities or houses of worship.

The pattern is consistent: each new law narrows what agencies can do with plate data or where they can collect it, while the core structure holds. Publish a policy, log every search, secure the data, and delete it. Agencies that skip those obligations expose themselves to legal challenge, and the direction of travel is toward tighter enforcement, not looser.

1
California Legislative Information. California Code CIV 1798.90.51 – Collection of License Plate Information
2
California Legislative Information. California Code CIV 1798.90.53 – Collection of License Plate Information
3
California Legislative Information. California Code CIV 1798.90.52
4
California Legislative Information. California Penal Code – AB-1242 Reproductive Rights
5
California Legislative Information. California Values Act – SB 54
6
Northern California Regional Intelligence Center. California Law Enforcement ALPR FAQ
7
Supreme Court of the United States. Carpenter v. United States, No. 16-402
8
LegiScan. California Senate Bill 274