Schmidt v. City of Norfolk Brief: Automated License Plate Readers Commit Fourth Amendment Searches

Matthew Cavedon

Norfolk, Virginia, has deployed nearly 200 automated license plate readers (ALPRs) across the city, capturing every passing vehicle’s location, time, and identifying details—and storing that data for weeks. Now, two residents are suing, arguing that this sweeping, warrantless tracking of their daily movements amounts to unconstitutional surveillance under the Fourth Amendment.

ALPRs “are high-speed, computer-controlled camera systems” that capture all license plate numbers, along with the location, date, and time. Norfolk has deployed advanced ALPRs from the technology company Flock that use artificial intelligence to record the make, type, color, and distinctive features of a vehicle (like bumper stickers) to create a trackable “Vehicle Fingerprint.” They are capable of revealing how fast and in what direction a person traveled and can even reconstruct a vehicle’s historical routes over time. In just a matter of keystrokes, officers can chart a person’s full movement across a city over a specific timeframe, with almost no restrictions or oversight. The ALPRs installed by the City of Norfolk automatically record every vehicle that passes by and archive that information for 21 days.

The Appellants in this case—Lee Schmidt and Crystal Arrington—are Norfolk residents whose cars are captured by the city’s ALPRs, sometimes several times per day. They sued, alleging that the city’s warrantless collection of their movements throughout the city—and retention of those records for future review and inspection—violates the Fourth Amendment. The district court dismissed their complaint, holding that the ALPRs do not violate the Fourth Amendment because they do not track “the whole” of their movements.

Although the city’s ALPRs are stationary and do not persistently track people the way a cell phone or a drone can, the public nature of a roadway is not a blank check for government surveillance. The Supreme Court once held that a person has no expectation of privacy in “movements from one place to another,” but it has since refined that analysis. As technology has advanced, the Court has recognized that even data collected in public spaces can offer an intimate window into a person’s life—revealing where they travel, how often, and for how long—and that “more sophisticated” surveillance methods can violate the Fourth Amendment. Norfolk’s ALPR network qualifies as such a system.

Cato has filed an amicus brief to highlight two points. First, the Fourth Amendment was designed to eliminate indiscriminate searches and the threat of “general warrants” that allowed British officials to rummage through Americans’ homes and papers. Today’s technology poses an analogous threat: with no probable cause, government officials can now collect and store intimate details of a person’s life—including financial information and location information—for perusal at the click of a button. Without judicial oversight, tools like ALPRs give police the discretionary power to conduct suspicionless searches that the Framers sought to prohibit.

Second, the district court’s rule—accepting all government tracking short of the very most exhaustive kind—would invite the warrantless deployment of many technologies to surveil the public. Modern surveillance tools such as ALPRs, military-grade drones, financial “audit trails,” and other technologies and sensors let the government monitor millions of people with ease, tracking movements, detecting faces, recording digital conversations—then storing everything for later review. Left unchecked, such tools would render the Fourth Amendment’s warrant requirement a dead letter.

Cato has asked the Fourth Circuit Court of Appeals to reverse the decision and to foreclose a surveillance apparatus that silently records the daily movements of every Norfolk resident who ventures onto a public street.