Written by David Boyer, Partner. Last updated October 5, 2026.

Are Flock Cameras Constitutional?

Federal courts have a long history of being behind the times when it comes to technological advancements. A big part of this is simply because courts tend to move as slow as molasses while technology evolves at an exponential rate. With the rise of AI, a whole new host of legal issues are quickly developing and percolating in courts across the country. Given the novelty of AI and its capabilities, courts are now faced with brand new legal challenges. Perhaps the biggest and most anticipated legal analysis that is currently brewing is the constitutionality of Flock and AI-powered cameras.

In October 2026, a U.S. District Judge in Oklahoma issued an opinion on whether Flock and other Automated License Plate Reader (“ALPR”) technology is a violation of one’s right to be free from unreasonable searches under the Fourth Amendment. The Oklahoma judge relied on recent Supreme Court precedent surrounding the unlawful use of cell phone data to track individual’s movements, and applied this logic to the dragnet-style surveillance of Flock cameras and ALPR technology.

What is Flock and ALPR Technology?

Automated license plate readers are exactly what they sound like–AI-computer-controlled cameras that automatically take pictures of license plates as they pass by. These cameras are usually installed on street poles, lights, overpasses, and sometimes attached to police cars. ALPRs capture images of all license plates that pass by, and stores the location, date, and time the image is captured. These images are then uploaded to a central server where law enforcement who have contracts with the ALPRs can access it at any time.

With this information, law enforcement can track a person’s movements across the country over a period of time, giving them far more personal information on a suspect than traditional, warrantless surveillance can. Officers can use information from ALPRs to piece together a person’s travel history whether simply running to the grocery store or taking a cross-country roadtrip.

What this means is that Flock cameras and ALPR technology allow law enforcement (as well as private companies) to view a person’s historical and real time location information to an unprecedented extent. Importantly, it does not matter if you are suspected of a crime or a target of investigation, ALPRs captures and stores data on every single license plate that passes by.

It would seem pretty obvious then that Flock and ALPRs violate the Fourth Amendment. Unfortunately, because of how Fourth Amendment case law has developed with respect to rapidly advancing technology, it is not that simple.

The Fourth Amendment and the Expectation of Privacy

The Fourth Amendment to the United States Constitution states:

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

For over a century this one sentence has been at the heart of numerous cases to determine just what is and is not covered by the Fourth Amendment. Law schools can spend an entire semester going over all of the Fourth Amendment jurisprudence, but for this article we are only going to talk about a few select cases that are most relevant to the question of whether Flock cameras violate the Fourth Amendment.

At the core of the Fourth Amendment is every person’s right to a reasonable expectation of privacy. Almost 60 years ago, the Supreme Court explained, “What a person knowingly exposes to the public, even in his own home or office, is not a subject of a Fourth Amendment protection. But what he seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected.” United States v. Katz, 389 U.S. 347 (1967). In Katz, the Supreme Court held that the Fourth Amendment protected Katz’ conversation on a public payphone from law enforcement’s warrantless recording of the conversation.

Sixteen years later, the Court revisited its reasonable expectation of privacy decision in United States v. Knotts, 460 U.S. 280 (1983). The Court was tasked with determining whether placing an electronic beeper in someone’s vehicle and following the signal was a violation of the Fourth Amendment. The Court diverged from its prior decision in Katz and found no constitutional violation because “[a] person traveling in an automobile on public thoroughfares has no reasonable expectation of privacy in his movements from one place to another.” That is, when a person travels in public, “he voluntarily convey[s] to anyone who wanted to look the fact that he was traveling over particular roads in a particular direction, the fact of whatever stops he made, and the fact of his final destination when he exited from public roads onto private property.”

Knotts remains the law today, and is the bedrock of the government’s argument that Flock and ALPR technology does not violate the Fourth Amendment. Essentially, the argument goes that because there is no expectation of privacy on the open roads, license plate readers are not unconstitutional under the Fourth Amendment.

Reasonable Expectation of Privacy in the 21st Century

With no reasonable expectation to privacy on the open roads being the state of the law, it would seem that the Fourth Amendment does not protect against Flock cameras. However, federal courts have not completely turned a blind eye to the advancement of technology when it comes to Fourth Amendment protections. Two major Fourth Amendment cases have been handed down by the Supreme Court in the past decade that have a significant impact on technological advancements by law enforcement.

The first case is United States v. Carpenter, decided in 2018, which held that people have a reasonable expectation of privacy in their physical movements that are captured by cell-site location information (CSLI).  The facts of Carpenter get highly technical, but in a nutshell law enforcement obtained several days of CSLI from wireless carriers to track a suspect’s location in investigating a robbery. This is information automatically captured and stored by wireless carriers and can be used to piece together a person’s location and movements over the course of a given period of time. The Supreme Court found this kind of surveillance protected by the Fourth Amendment. In addressing its earlier decision in Knotts, the Court wrote: “[The Court in Knotts] was careful to distinguish between the rudimentary tracking facilitated by the beeper and more sweeping modes of surveillance.”

In a very recent case decided just this past summer, the Supreme Court again addressed police’s mass surveillance using cell phones in Chatrie v. United States. This time, instead of CSLI the Court addressed whether law enforcement could use Google’s Location History data through a geofence warrant to track the movements of individuals suspected of a crime. And once again, the Court found that people have a Fourth Amendment right to privacy in their location.

The basic purpose of the Fourth Amendment is to safeguard the privacy and security of individuals against arbitrary invasions by governmental officials.

Notably, neither Carpenter nor Chatrie overruled Knotts. Instead, the Court determined that Knotts did not stand in the way of its decision in those two cases. So how can courts square away the idea that there is no right to privacy on the open roads, but people have an expectation of privacy in their movements including in public places?

Do Flock Cameras Violate the Fourth Amendment?

To be clear, no higher federal courts have held that Flock cameras and ALPR technology violates the Fourth Amendment. However, there are cases currently pending in the courts of appeals that could change this in the future. However, this month a federal U.S. District Judge in the District of Oklahoma found Flock surveillance to be unconstitutional based on the Fourth Amendment.

In United States v. Kyle, the defendant sought to suppress the evidence obtained from a traffic stop in Tulsa, Oklahoma. A police officer saw a Mazda SUV with a California license plate. Apparently for no reason other than the out-of-state plates, the officer began following the vehicle. The officer accessed the Flock system while following the Mazda and ran the plate. After running the ALPR query, the officer saw that the Mazda had traveled from Oklahoma to the California/Arizona border area and was heading back over the course of a few days.

The officer proceeded to pull over the Mazda driver for following too closely to a vehicle. Despite the reason for pulling over the SUV being “following too close” the officer began asking the driver questions about their trip to California/Arizona based on information gathered by Flock. The driver gave valid reasons for the trip which did not contribute to reasonable suspicion in the court’s view.

The officer gave the driver a written warning, which officially ends a traffic stop. However, after issuing the warning, the officer asked if he could run a drug dog to conduct a sniff of the car. The driver declined consent, and was then arrested. The driver filed a motion in the U.S. District Court to suppress any evidence that came of the stop for multiple Fourth Amendment violations including the use of Flock cameras.

U.S. District Judge Sara Hill found that the officer’s use of ALPR systems was an unconstitutional warrantless search. 

The government had argued that the information collected by ALPR technology was in plain view on public roadways which meant the defendant did not have a reasonable expectation of privacy in this information. And the court found that other Oklahoma federal courts had decided the issue in agreement with the government’s reasoning.

But the district judge wrote that she was concerned that these decisions gave too much weight to the language in Knotts without adequately accounting for the context of ALPR technology and the Supreme Court’s more recent decisions on large-scale data collection of an person’s location.

More than 40 years have passed since the Supreme Court’s decision in Knotts, and this Court is now faced with technology that appears to be approaching the dragnet type law enforcement practice Mr. Knotts warned of. Therefore, lower courts need to reexamine the result in Knotts as technology advances past the rudimentary beeper in that case. Adhering too strictly to the Supreme Court’s language in Knotts about a person’s reasonable expectation of privacy in “his movements from one place to another” risks ignoring the Fourth Amendment principles at stake.

The Oklahoma district court went into great detail on the Supreme Court’s decisions in Carpenter and Chatrie, and likened the Fourth Amendment violations in those cases as similar to those posed by Flock cameras and ALPRs in general. The court recounted how the officer in this case had access to a month’s worth of the defendant’s location data tied to the license plate, including fifty sighting across multiple states. A level of surveillance far more advanced and intrusive than the common radio beeper used in Knotts. What’s more, law enforcement has on-demand access to this information for every vehicle caught on a Flock camera.

Think about it this way. We might reasonably expect our friends and family to tell us something like: “Hey, I saw you out driving by the store last week.” But we do not expect people we know–let alone strangers, and especially not law enforcement–to randomly approach us to say: “Hey, I have been following your car for the last 30 days, and here is a detailed log of every place your vehicle has been with supporting photographic evidence. I am also going to share this information with law enforcement throughout the country so they know your whereabouts, too.”

The district court held that police’s use of Flock cameras and ALPR technology was a search that violated the Fourth Amendment. The defendant’s motion to suppress was granted.

We believe in giving credit where credit is due. No other judge in Oklahoma has previously held Flock cameras to be unconstitutional, and several have denied similar motions for other defendants. Here, there were a lot of problems with the traffic stop. The judge could have granted the motion to suppress on several other grounds and simply not decided the constitutionality of Flock cameras. Instead, this judge found the stop unconstitutional based on the Flock cameras as well as other issues not addressed in this article.

What Happens Next for Flock?

To be clear, federal circuit courts and the U.S. Supreme Court have not yet ruled on the constitutionality of Flock cameras. There have been a few district court decisions with varying degrees of results. This means that none of those decisions are binding on other district judges. However, it is only a matter of time before a U.S. Court of Appeals answers whether ALPR and Flock violate the Fourth Amendment. And then, we can expect with almost certainty that the Supreme Court will address this issue in time.

Just yesterday the Fifth Circuit Court of Appeals heard oral argument on this very issue in United States v. Brownlee, No. 25-10855. There are other courts of appeals across the country that are likely to rule on this issue within the year or early next.

If and until a federal appellate court issues a published opinion on the constitutionality of Flock cameras, we are unlikely to see a change in how law enforcement officers use this expansive technology to monitor people’s locations. Even then, it will take a decision from the U.S. Supreme Court to see a ruling that affects the entirety of the nation.

About Evergreen Attorneys

Evergreen Attorneys is a federal criminal defense practice that focuses exclusively on federal matters. The firm represents clients nationwide in federal investigations, federal trial defense, and related proceedings.

Clients facing federal criminal exposure choose Evergreen Attorneys for several reasons:

• Exclusive federal focus: Every case the firm handles is a federal matter. This means the attorneys work within the Federal Rules of Criminal Procedure, the United States Sentencing Guidelines, and federal rules of evidence every single day.
• Partner-level representation: Evergreen Attorneys provides only partner-level representation. Clients work directly with a named partner throughout the case.
• Nationwide reach: The firm serves clients in federal districts across the country, including in Oklahoma federal courts, without the limitations of a single-state practice.
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• U.S. Supreme Court Winners. Evergreen Attorneys secured a 9-0 victory for their client in United States v. Hemani at the U.S. Supreme Court.

Frequently Asked Questions

What are Flock cameras?

Flock cameras are automated license plate reader (ALPR) cameras that use computer technology to photograph vehicles and license plates. They record information such as the vehicle’s location, date, and time and store that information in a database accessible to law enforcement agencies that use the system.

What information do Flock cameras collect?

Flock cameras can capture a vehicle’s license plate and information about where and when the vehicle was observed. Because the information is stored, law enforcement can potentially use ALPR data to reconstruct a vehicle’s movements over an extended period of time.

Are Flock cameras a violation of the Fourth Amendment?

The answer is not yet settled nationwide. A federal district judge in Oklahoma recently held that law enforcement’s use of Flock and ALPR technology violated the Fourth Amendment in a particular case. However, no federal circuit court or the U.S. Supreme Court has issued a definitive ruling holding that Flock cameras are unconstitutional.

What does the Fourth Amendment have to do with Flock cameras?

The Fourth Amendment protects people against unreasonable searches and seizures by the government. The central question with Flock cameras is whether a person has a constitutionally protected expectation of privacy in the historical record of their movements that is created by ALPR technology.

Does the Kyle decision apply nationwide?

No. The decision was issued by a federal district court, meaning it is not binding on federal courts throughout the country.

What should I do if police used Flock cameras to investigate me?

If Flock or ALPR information played a role in a traffic stop, search, arrest, or criminal investigation, an attorney can examine how the information was obtained and used and whether there are grounds to challenge it under the Fourth Amendment. The developing case law makes the specific facts particularly important.

If you are facing federal charges or a federal investigation, contact Evergreen Attorneys today. We can be reached at (303) 948-1489 or by email at [email protected].