Does the Fourth Amendment Protect You From Flock Cameras? Carpenter v. United States Explained

The Fourth Amendment protects you from unreasonable search and seizure. Flock cameras photograph your car 47 times per day in some Wisconsin counties. A Price County criminal defense attorney says the two concepts are on a collision course.

Quick Answer: Does the Fourth Amendment protect you from Flock camera surveillance? Legal analysis of Carpenter v. United States and ALPR technology in rural Wisconsin.

Quick Answer: Does the Fourth Amendment protect you from Flock camera surveillance? Legal analysis of Carpenter v. United States and its application to ALPR technology in rural Wisconsin. The answer depends on which circuit you’re in.

In 2018, the Supreme Court ruled that police need a warrant to track your phone’s location over time. Your car is a different story. The same kind of location tracking that the Court called a Fourth Amendment violation when done with cell phone data is happening right now to every vehicle that passes a Flock camera in Price County, without a warrant.

TLDR: Carpenter v. United States (2018) established that warrantless digital tracking of a person’s movements violates the Fourth Amendment. Legal scholars argue ALPR networks like Flock create the same comprehensive tracking, but a federal judge in Virginia ruled that Flock’s discrete photos don’t qualify. No court has ruled on ALPR constitutionality in Wisconsin, meaning Price County’s 10 surveillance devices operate in a legal gray area.

Carpenter v. United States, Explained

Timothy Carpenter was convicted of a string of robberies based partly on 127 days of cell-site location information (CSLI) that the FBI obtained without a warrant. The government argued that Carpenter had no reasonable expectation of privacy because he voluntarily shared his location data with his cell phone carrier.

The Supreme Court disagreed. In a 5-4 decision written by Chief Justice Roberts, the Court held that **accessing seven days or more of CSLI constitutes a Fourth Amendment search requiring a warrant.** The reasoning was that prolonged digital surveillance reveals “an intimate window into a person’s life” that goes beyond what a person knowingly exposes to the public.

The Carpenter ruling established a new framework for digital privacy: even if individual data points are collected by third parties and technically visible to the public, the aggregation of that data over time can create a Fourth Amendment-protected picture of a person’s life.

How ALPR Creates the Same Tracking Carpenter Protected

Automated license plate readers do with cars what cell-site towers do with phones. Flock cameras photograph every plate that passes, log the time and GPS coordinates, and store the data for months or years. When you aggregate scans from multiple cameras across a network, you get a comprehensive picture of a vehicle’s movements, not unlike CSLI.

**The Washington University Law Review published a detailed analysis arguing that ALPR data should constitute a search under Carpenter.** Author Stephanie Foster writes: “Given that automated license plate readers can reveal so many intimate details about our lives, is there a reasonable expectation of privacy with regard to the use of this information?”

The argument is straightforward. A single Flock scan tells you a car was at a specific intersection at a specific time. Is public information, visible to anyone standing on the corner. But 90 days of Flock scans across 10 cameras reveal where someone worships, where they drink, who they visit, and when they leave town. Is the kind of “comprehensive” tracking that Carpenter said requires a warrant.

The Norfolk Ruling: Courts Are Split

Not every court agrees. In 2024, U.S. District Court Judge Mark Davis ruled that Norfolk, Virginia’s use of Flock ALPR cameras is constitutional. The judge reasoned that Flock cameras take “discrete pictures at different locations” rather than continuously tracking a vehicle’s movements.

**”Because rapid technological advances, such as the rise of artificial intelligence, make it impossible to predict how police surveillance will evolve, the Court declines to speculate about future technologies,”** Judge Davis wrote. He framed Flock as taking individual photographs, not creating a tracking database, even though that is precisely what Flock’s platform does.

The plaintiffs in the Norfolk case argued that ALPR data reveals intimate details about a person’s life, echoing the Carpenter framework. Judge Davis acknowledged that the technology “certainly raises privacy questions” but concluded that discrete photographs at fixed locations do not constitute a search under the Fourth Amendment.

The ruling is not binding on Wisconsin courts. It applies only to the Eastern District of Virginia. No federal court in the Seventh Circuit (which includes Wisconsin) has ruled on the question.

Wisconsin’s Legal Landscape for ALPR

Wisconsin has no state law specifically regulating ALPR use by law enforcement. There is no statute requiring a warrant for ALPR queries, no retention limit for how long data can be stored, and no restriction on sharing data with federal agencies.

**Several states have passed ALPR-specific legislation.** California’s SB 241 restricts data sharing with out-of-state and federal agencies. New Hampshire requires a warrant for ALPR searches. Maine limits data retention to 21 days. Virginia debated restrictions after the Norfolk ruling.

Wisconsin has none of these protections. The Price County Sheriff’s Office can store Flock data indefinitely, share it with any agency on the Flock platform, and run lookups for federal agencies like ICE without legal constraint.

Price County’s Flock Vote and Your Rights

On August 15, 2024, the Price County board approved the purchase of Flock cameras with a single motion. “Motion by Supervisor Palecek, seconded by Supervisor Barkstrom, to reallocate 2024 debt proceeds for the purchase of Flock cameras for the Sheriff’s Office. Carried with no dissent.”

There was no public hearing. No discussion of data retention policies. No mention of federal data sharing. No debate about Fourth Amendment implications. The motion passed unanimously with no dissent.

**Price County now operates 10 surveillance devices: four Flock ALPRs, two unbranded ALPRs, and four gunshot detectors.** Every vehicle that drives through Phillips or Park Falls has its plate scanned and logged. The data enters a nationwide network of over 150 million daily scans. No warrant is required. No suspicion is needed. No one is notified.

The Carpenter ruling suggests this should concern anyone who cares about the Fourth Amendment. The Supreme Court said that aggregated digital tracking of movements requires a warrant. Flock’s network aggregates license plate scans across thousands of cameras, creating exactly the kind of comprehensive movement record that Carpenter protected.

What You Can Do

If you are concerned about ALPR surveillance in Price County:

1. Contact your county board supervisor. Price County has 21 supervisory districts. Find your supervisor on the Price County website and ask whether they support data retention limits and warrant requirements for Flock queries.

2. File a public records request. Wisconsin Statute § 19.35 gives you the right to request government records. Ask the Sheriff’s Office for their Flock data retention policy, sharing settings, and any federal lookup requests.

3. Support state-level ALPR legislation. No Wisconsin bill currently regulates ALPR use. Contact your state senator and representative to ask them to introduce legislation similar to California’s SB 241.

4. Attend county board meetings. The Price County board meets monthly. Public comment periods allow you to raise concerns about surveillance policy directly with the supervisors who approved it.

FAQ

Does Carpenter v. United States apply to Flock cameras?

Legal scholars argue it should. The Supreme Court ruled that warrantless digital tracking of movements over time constitutes a Fourth Amendment search. ALPR networks create similar tracking by aggregating license plate scans. However, a federal judge in Virginia ruled that Flock’s discrete photos don’t qualify as continuous tracking. No court has ruled on this question in Wisconsin.

Does Wisconsin require a warrant for ALPR lookups?

No. Wisconsin has no state law requiring a warrant for ALPR queries, limiting data retention, or restricting data sharing with federal agencies. Law enforcement can run Flock lookups without any suspicion or warrant.

How long does Price County store Flock data?

Unknown. The Price County Sheriff’s Office has not publicly disclosed its data retention policy. Flock’s default retention period varies by contract, and some systems store data for up to five years. We have filed a public records request to determine Price County’s specific retention settings.

Did Price County residents get to vote on Flock cameras?

No. The Price County board approved Flock cameras on August 15, 2024 with a single motion to “reallocate 2024 debt proceeds.” No public hearing was held, and no referendum was conducted. The motion passed with no dissent.