Federal Court Deems the Use of Flock Camera Data a Fourth Amendment Search

About a month ago, I posted about Flock cameras. I noted that litigants in both civil and criminal cases had begun to argue that the use of such cameras – more precisely called automatic license plate readers or ALPRs – constitutes a search under the Fourth Amendment and therefore is unlawful absent a search warrant or an exception to the warrant requirement. At that time, those arguments had been unsuccessful. But now one has succeeded.

The case in question is United States v. Kyle, a federal criminal case pending in the Northern District of Oklahoma. It arose when a deputy sheriff in the Sooner State saw a vehicle with a California plate drive by. The officer used Flock’s interface to conduct a national search for the plate and found that the vehicle was returning from a brief trip from Oklahoma to California.

The brevity of the trip piqued the officer’s interest based on his training in highway drug interdiction. He followed the vehicle, observed several traffic violations, and pulled it over. The stop eventually resulted in the discovery of drugs, which led to federal charges against the driver.

The driver moved to suppress the evidence uncovered during the stop. One of the grounds for the motion was her contention that when the officer ran the plate through Flock’s interface, he conducted an unlawful search. She argued that she had a reasonable expectation of privacy in her location, based on the rulings of the Supreme Court of the United States in Carpenter v. United States, 585 U.S. 296 (2018) (concerning cell site location information), and Chatrie v. United States, __ U.S. __ (2026) (concerning location history information collected by Google concerning certain users of Google services).

The government responded that ALPRs only establish a person’s location on the public roadways. The Supreme Court stated in United States v. Knotts, 460 U.S. 276 (1983), that a person “travelling in an automobile on public thoroughfares has no reasonable expectation of privacy in his movements from one place to another.” Therefore, the government concluded, the use of ALPRs is not a search for Fourth Amendment purposes.

The judge acknowledged in her order that “nearly every court examining the issue to date” had agreed with the government’s position. However, she noted that in Knotts itself, the Court stated that if “dragnet type law enforcement practices . . . should eventually occur . . . different constitutional principles may be applicable.” And she concluded that ALPRs constitute a digital dragnet. As applied to defendant Kyles, ALPRs provided “an entire month’s worth of location data . . . including more than fifty sightings across multiple states.”

The judge acknowledged that “[t]his is not the same fine-tuned level of detail that something like a cell phone reveals about the whole of someone’s physical movements.” But she emphasized that ALPRs do not track just one vehicle. Rather, they provide “access to a continuously updated location history for all vehicles caught on ALPR cameras within the network.” The judge viewed this as a form of “indiscriminate mass surveillance” that “is not targeted on a single individual.” That may be so, but I would have liked to see more explanation of why it is pertinent to the issue at hand. Fourth Amendment rights are personal rights, so I doubt that law enforcement’s monitoring of the location of person X can become a search by virtue of the fact that law enforcement is also monitoring the location of person Y.

The judge also looked to the future. She stated that it “is not difficult to imagine what is next: more cameras on more street signs, buildings, and perhaps on more police cars.” Even “a fleet of drones hovering over an entire city so they don’t miss the movement of a single vehicle.” Again, the judge may be close to the mark as a factual matter, but the possibility that law enforcement may expand the use of a technology tomorrow does not seem to render its more limited use today improper.

Whatever the strengths and weaknesses of the opinion, the bottom line is that the judge determined that the officer’s decision to access the ALPR data was a search. Because the search was done without a warrant or an exception to the warrant requirement, it violated the Fourth Amendment. The stop, and all the evidence discovered during the stop, was fruit of the poisonous tree and subject to suppression. Whether other courts will follow suit remains to be seen. If they do, I hope to blog about it here.