Police are using AI-scanned license plate data to flag "suspicious" road trips
The ACLU warns that automated plate readers and AI pattern tools are triggering traffic stops based on travel history alone, not any suspected crime.
What happened: The ACLU published an account of Grace Knowles, a Virginia woman pulled over in Oregon last September after a state trooper said she'd spent too much time in the left lane. The stop escalated when an FBI agent working a trafficking case told her that her license plate had been flagged for a 'suspicious' travel pattern. He showed her a heat map built from camera footage tracking her route across several states, generated from automated license plate reader (ALPR) data.
Why it matters: ALPR networks from companies like Flock Safety and Axon were originally pitched for solving specific crimes. The ACLU says agencies are now using the accumulated data and AI tools to flag ordinary travel, like driving overnight between two cities, as grounds for a stop, with no suspected crime or specific suspect attached. People are being pulled over, questioned, and searched based on movement patterns alone.
How it works, plainly: Cameras mounted on highways, signs, and poles photograph passing plates and log the time and location. Flock and similar vendors have built tools that stitch these sightings into a travel history for any given vehicle. Officers can then query that history, and AI analysis highlights trips that resemble patterns tied to trafficking or drug routes, such as a quick overnight trip to a specific city, prompting a stop even when nothing else points to wrongdoing.
The rollout: Pushback is growing. A YouGov survey in August found 46% of respondents opposed police use of this technology versus 38% in support. The Los Angeles Police Department and other agencies have dropped or suspended Flock contracts. Courts are pushing back too: a federal jury in Texas awarded damages to a man stopped over a flagged overnight trip, and a judge separately called one Flock-based search 'indiscriminate mass surveillance' and tossed the evidence.
