Use of License Plate Readers Spreading Across Washington

Automated License Plate Readers (ALPRs) | Electronic Frontier Foundation

Excellent article by journalist Natalie Swaby says cities across Washington are turning to technology and using automated license plate reader cameras to combat crime.

The use of automated license plate readers (ALPR) is spreading fast across city and state law enforcement agencies.


ALPRs are high-speed, computer-controlled camera systems that are typically mounted on street poles, streetlights, highway overpasses, mobile trailers, or attached to police squad cars. ALPRs automatically capture all license plate numbers that come into view, along with the location, date, and time. The data, which includes photographs of the vehicle and sometimes its driver and passengers, is then uploaded to a central server.

Law enforcement agencies use ALPR systems for the authorized law enforcement purpose of rapidly identifying and locating vehicles of legitimate interest to law enforcement. In one common use of ALPR technology, license plate encounters are compared against law enforcement databases, also known as “hot lists”. The lists contain the license plate numbers and letters of vehicles associated with active investigations, such as those related to Amber Alerts or other missing persons, stolen vehicles, or stolen license plates. The information is also retained for a fixed retention period, though it is only re-accessible by law enforcement given a legitimate law enforcement purpose.

A second common use of ALPR technology is to canvas license plates around any crime scene to assist in the identification of suspects, victims, and witnesses. ALPR technology only acts as a pointer system that allows law enforcement to conduct searches with limited information, including partial license plate information.


ALPR units are attached to law enforcement vehicles or deployed at fixed locations, where they collect license plate information from vehicles on public roadways, public property and vehicles that are within public view. As the ALPR devices are a law enforcement investigative tool we do not provide the locations of the cameras. If subjects engaged in violent and/or serial criminal activities are made aware of the location of the devices, they could take measures to avoid detection.

The City of Tukwila issued a notice out about six months ago, letting people know they’d be using solar-powered cameras that are motion activated by vehicles. Police say it helps them investigate crimes. Software on the camera compares the license plate to different crime databases. If the camera catches a license plate that is on a crime database, law enforcement is alerted immediately.


The ACLU of Washington says they are currently working to make sure there are clear guidelines for how government agencies use the technology.

“The information captured by the readers – including the license plate number, and the date, time, and location of every scan – is being collected and sometimes pooled into regional sharing systems. As a result, enormous databases of innocent motorists’ location information are growing rapidly. This information is often retained for years or even indefinitely, with few or no restrictions to protect privacy rights.” ~ACLU

Please contact my office if you, a friend or family member are charged with a crime involving ALPR technology. Hiring an effective and competent defense attorney is the first and best step toward justice.