EFF and ACLU Ask Sixth Circuit to Require Warrants for ALPR Location Searches

The Electronic Frontier Foundation and the American Civil Liberties Union have filed a friend-of-the-court brief with the US Court of Appeals for the Sixth Circuit, urging the court to hold that police need a warrant before searching automated license plate reader (ALPR) databases to reconstruct a person's movements.

The case, United States v. Sturdivant, tests whether the Fourth Amendment's warrant requirement reaches a surveillance layer that, according to EFF, continuously records drivers across the country and stores those records in databases officers can query at will. The brief argues this kind of tracking qualifies as a search under the Constitution.

How the case began

According to EFF's account, the investigation started with a string of robberies in and around Cleveland, Ohio. Surveillance footage let officers identify the make, model and color of a car they believed was involved, but they had no license plate number. Rather than seeking a warrant, they ran broad, untargeted queries across two ALPR databases — those run by Flock and ELSAG — and found that a vehicle registered to the defendant had been recorded near the robbery locations. That lead produced an arrest.

The defendant then moved to suppress the ALPR evidence. The district court declined, reasoning that a plate number is visible to anyone on the street, so the driver had no reasonable expectation of privacy in it and no Fourth Amendment interest in having his car tracked in public places.

Why the groups say ALPRs are different

The heart of the EFF and ACLU argument is that mining an ALPR archive bears no resemblance to a bystander noticing one plate on one passing car. EFF has argued for years that the technology gives law enforcement the practical ability to reconstruct nearly anyone's past travels with a few clicks, and that a nationwide, interconnected camera network makes retrospective location tracking routine.

EFF also points to a decision from another federal district court last month, which concluded that plate readers function as dragnet surveillance that can violate the Fourth Amendment. That outcome sits in tension with the ruling against Sturdivant, and the groups say the disagreement is exactly why the appeals court should step in. EFF is separately litigating direct challenges to ALPR programs in San Jose, California and Wisconsin.

A network under growing scrutiny

The filing lands amid wider friction over how police handle plate reader data. EFF and the ACLU of Northern California recently criticized the Marin County Sheriff's Office for sharing Flock ALPR records with out-of-state and federal agencies, which the groups say violates California law. EFF has also documented what it describes as a permissive culture around these databases — minimal audits, no warrant requirement and casual access that lets officers treat them as a personal search engine for everyone's location history. At the same time, the organization notes that officials in Texas and Florida have recently moved to pull back from ALPR deployments.

Why it matters

If the Sixth Circuit sides with the civil liberties groups, police in the circuit would generally need a warrant before digging through ALPR archives for a person's location history. Because these camera networks span jurisdictions and share data across agency lines, the ruling's practical reach would extend well beyond Ohio. An affirmance, on the other hand, would endorse the lower court's logic — that information theoretically observable in public can be aggregated at scale without judicial oversight — a precedent with obvious implications for other bulk camera and location systems. Either way, the decision will help determine whether Fourth Amendment doctrine keeps pace with infrastructure that has quietly made retrospective tracking a routine database query.