An automated license plate reader (ALPR) system consists of one or more mobile or fixed high-speed cameras and software that automatically capture license plate images and convert them into machine-readable text.  An ALPR system may also capture contextual images, such as a part of the vehicle, the vehicle's make and model, occupants, and immediate vicinity. 

An ALPR system creates records of vehicle activity by pairing captured images and license plate text with the information about the date, time, and location of where the vehicle was detected.  Historical data may be generated by searching an ALPR system database for specific vehicle data, returning all instances when that plate was detected, and producing a map of where that vehicle has been over a set time period.  An ALPR system also compares license plate numbers to generate a real-time alert and to identify the current location of a vehicle if the vehicle's license plate number is a match to a particular database or watch list.  Both real-time and historical ALPR data may also be used to geofence an area of interest and to monitor vehicles in a specified geographic location.

The most notable usage of ALPR is for identifying and locating stolen vehicles.  Automated license plate reader systems may also be used to assist in locating a person of interest, such as a suspect or a missing person, and in parking or toll enforcement.

Sixteen states, including California, Florida, and Utah, have enacted laws regulating the use of ALPR systems and associated data.

State and local government agencies are generally prohibited from using ALPR systems.  Only certain agencies may access, operate, or use ALPR systems and associated data for specifically authorized purposes.  Authorized agencies are prohibited from certain practices and must comply with the registration, reporting, and audit requirements, as well as with prescribed retention periods for ALPR data. 

Law Enforcement.

A law enforcement agency may use an ALPR system for the purpose of comparing ALPR data with:

• data on any of the specified watch lists maintained by a federal or Washington agency; or
• license plate numbers that have been manually entered into an ALPR database upon an officer's determination that the numbers are material to an investigation of a stolen vehicle, a vehicle associated with a missing or endangered person, a vehicle registered to a person for whom there is an outstanding felony warrant, or a vehicle involved in a felony.

A law enforcement agency that uses a watch list must ensure that the watch list is updated at least once every 24 hours.

A positive match by an ALPR system alone does not constitute reasonable suspicion as grounds for a law enforcement officer to stop the vehicle.  The officer must:

• develop independent reasonable suspicion for the stop; or
• confirm visually that the vehicle license plate matches the license plate image on the ALPR system and confirm by other means that the license plate number is on one of the specified watch lists. 

Parking Enforcement.

An ALPR system may be used for parking or toll enforcement as follows:

• as a component of a photo toll system;

• by a parking enforcement agency for the purpose of enforcing time restrictions on the use of parking spaces; or
• by a parking enforcement agency for the purpose of identifying vehicles on a watch list that contains only vehicles subject to impoundment or immobilization pursuant to a local ordinance and that is updated at least once every 24 hours.

Transportation Agencies.

A transportation agency may use an ALPR system to provide real-time traffic information, for traffic modeling or traffic studies purposes, or to enforce commercial vehicle systems at Washington State Patrol enforcement sites and weigh stations.

Prohibited Practices.

It is unlawful for any agency to use an ALPR system for immigration investigation or enforcement, any protected health care services, or to track or monitor an activity protected by the state Constitution and the First Amendment to the United States Constitution.

An agency may not:

• collect ALPR data on the premises or immediate surroundings of schools, places of worship, courts, food banks, any facility conducting an immigration matter, or facilities that provide protected health care; or
• sell, lease, rent, or purchase ALPR data or audit trail data.

An agency authorized to use an ALPR system may not:

• disclose, share or permit access to ALPR data except as required in a judicial proceeding; or
• provide direct access to its ALPR system to any entity except for other agencies authorized to use an ALPR system.

Data Retention and Public Records Exception.

Automated license plate reader data may not be retained for more than 72 hours, except in the following circumstances:

• When retained pursuant to a probable cause felony warrant or subpoena, ALPR data may be shared in discovery in accordance with court rules and must be deleted at the conclusion of the criminal or civil case.
• When retained by a law enforcement agency, ALPR data may be retained for as long as it is needed as evidence of specific unlawful conduct, the investigation of which constitutes an authorized use of an ALPR system by the law enforcement agency.
• When retained for parking enforcement, ALPR data must be deleted no later than 12 hours after collection.
• When retained for toll collection, ALPR data may be retained for as long as needed to support the assessment and collection of a toll.
• When retained for traffic studies, ALPR data must be deleted no later than 30 days after collection.
• When retained for enforcing commercial vehicle systems, ALPR data must be deleted no later than four hours after collection.

Automated license plate reader data is exempt from public records disclosure except for bona fide research that does not include individually identifiable information.

Other Requirements for Agencies Using Automated License Plate Reader Systems.

An agency may obtain privately-held ALPR data only pursuant to a probable cause warrant. 

Registration Requirements.

An agency that uses an ALPR system must register the system with the Attorney General and certify that the system meets all requirements of the law, the agency has policies governing the use of the ALPR system, and there is a documented training process for the officers that use the system.

Policies and Reporting Requirements.

By July 1, 2027, the Attorney General must develop and publish model policies on the use of ALPR systems by authorized agencies.  By December 1, 2027, an authorized agency must adopt policies consistent with the model policies and submit copies to the Attorney General or provide notice to the Attorney General that the agency did not adopt compliant policies, together with the reasons for any departures from the model policies.

By December 1, 2027, an authorized agency must submit an annual report on its ALPR system practices and usage to the appropriate committees of the Legislature.

Audit requirements.

An agency operating or accessing an ALPR system must maintain and retain for two years audit trail data that documents all access to and use of the system. 

Each agency must conduct an internal audit at least once a year to review all access to and use of the ALPR system and the agency's compliance with the data retention, sharing, and other requirements.  The State Auditor has jurisdiction to audit an agency's compliance with the law governing the use of ALPR systems.  

Requirements for Vendors and Operators of Automated License Plate Reader Systems.

An ALPR vendor must provide technical controls preventing unauthorized data sharing, secondary transfer, or access by nonauthorized agencies, including federal civil immigration enforcement.

If an ALPR operator accesses or provides access to ALPR data, the ALPR operator must maintain specified information as part of the record of that access and require that ALPR data only be used for the purposes authorized in the law.

Admissibility in Court.

Any information obtained in violation of the provisions governing the use of ALPR systems is inadmissible in any civil or criminal action, except in a civil action brought by a person injured by a violation and with the permission of the person whose rights have been violated.

Penalties and Remedies for Violations.

A violation of the provisions that govern the use of ALPR systems is a violation of the Consumer Protection Act. 

It is a gross misdemeanor to willfully and intentionally:

• query, access, or use an ALPR system for an unauthorized purpose; or
• retain, sell, share, permit access to, or disseminate ALPR data or audit trail data in violations of the provisions that govern the use of ALPR systems.

A person injured by a violation may bring a civil action to recover monetary damages and equitable relief, as well as reasonable attorneys' fees and the costs of the action.