The American Civil Liberties Union (ACLU) reported that police are increasingly using AI algorithms and automated license plate reader (ALPR) surveillance data to flag motorists whose travel histories appear “suspicious,” even without evidence of wrongdoing. Jay Stanley, a senior policy analyst with the ACLU Speech, Privacy, and Technology Project, expressed concerns that this approach to law enforcement would lead to an uptick in the controversial “pretextual stops,” arguing that “More and more people will be subject to police encounters as these AI algorithms inevitably sweep in far more innocent people than actual wrongdoers.”
ALPRs installed on roads and highways photograph passing vehicles, recording their registration numbers, locations, and timestamps. By combining sightings from different cameras, law enforcement can determine a vehicle's travel routes and frequency of visits to specific locations. An AI system accessing this surveillance data can analyze large amounts of data to identify patterns it is trained to deem as “suspicious,” which can trigger an alert to law enforcement. Stanley implies that officers may receive such an alert and then look for a minor traffic violation to justify pulling the driver over, sometimes concealing the actual reason for the stop.
The ACLU report details incidents, including one where a woman claimed an officer stopped her during a cross-country road trip because a surveillance system flagged her movements as suspicious after accessing ALPR data on her travel path. Another documented case involved police stopping a man who drove repeatedly between his home in Wisconsin and Michigan, leading authorities to suspect marijuana trafficking due to Michigan's legal status.
Security researchers have disclosed a network of over 335,000 Flock ALPR cameras across the United States. While ALPRs have historically aided police in tracking known suspects or locating vehicles associated with crime, the current scale and blanket surveillance are described as unprecedented. Companies like Flock Safety market AI-enhanced surveillance systems that can identify “unusual” travel behavior and associations between vehicles as crime-prevention tools.
Concerns regarding the technology extend to potential abuse, with reports noting that dozens of officers have been caught using the cameras to stalk ex-partners. Furthermore, the technology theoretically allows officers to track the movements of any vehicle that has passed ALPRs, and in some instances, authorities can build profiles by tracking associations between different vehicles and mobile devices. In response to such incidents, a Florida representative recently introduced a bill requiring warrants to search ALPR databases, though other politicians advocate for an outright ban on the technology.
