California law enforcement agencies utilize automated license plate readers (ALPR) that collect and store images of license plates as vehicles pass within an ALPR’s view. ALPRs are cameras that are located throughout a law enforcement agency’s jurisdiction atop fixed objects, such as light poles, and on moving objects, such as patrol cars. As the cameras capture the images of every vehicle that passes within its range, the images are converted into data that then goes into a searchable database. ALPR assists law enforcement in locating a vehicle involved in a crime, stolen vehicles, child kidnappings and other investigations.
For example, the police are alerted to an armed robbery after the suspects took off in vehicle that a witness was able to get a partial license plate read on before the vehicle sped out of view. By consulting the ALPR database in real time, the police are able to track any ALPR locations the vehicle passed, helping law enforcement locate the suspects.
The ALPR data is used to feed into “hot lists” that are lists of vehicle license plates connected to a crime investigation or associated with a person of interest. However, because ALPRs do not discriminate between license plates, every vehicle that drives by an ALPR is fed into the system. In Los Angeles County, 99.9 percent of the APLR license plates do not make a match to a hot list, but the data is stored anyway.