Automatic license plate readers, or ALPRs, have been in the news lately. Most ALPRs are made by a company called Flock Safety and therefore commonly are called Flock cameras. This post focuses not on the public debate about whether deploying such cameras is a good idea, but on the legal controversy about whether the use of Flock cameras without court supervision constitutes an unreasonable search in violation of the Fourth Amendment. To set expectations, this post is going to be a short introduction to a complex topic.
The nub of the legal issue is whether Flock cameras enable law enforcement to track drivers’ movement over time in a way that is comprehensive enough to constitute a search under the Fourth Amendment. The most pertinent Supreme Court cases in this area are United States v. Jones, 565 U.S. 400 (2012) (holding that GPS tracking is a search), and Carpenter v. United States, 585 U.S. 296 (2018) (holding that cell-site tracking is a search).
Litigants are presenting this issue to the courts through two major pathways. First, when information captured by Flock cameras is evidence against a criminal defendant, the defendant may argue that the information was obtained unconstitutionally and should be suppressed. Second, individuals who have not been charged with a crime but who do not want to have their license plates captured may file suit under 42 U.S.C. § 1983 against a law enforcement agency or a unit of local government that has contracted with Flock, alleging that the use of the cameras violates the individuals’ constitutional rights.
The use of both pathways to raise issues about police use of surveillance tools is typical. Jones and Carpenter arose out of criminal defendants’ motions to suppress evidence. By contrast, Leaders of a Beautiful Struggle v. Baltimore Police Department, 2 F.4th 330 (4th Cir. 2021), a case contesting the constitutionality of a persistent aerial surveillance program, was a section 1983 case brought by community advocates.
So far, Flock Safety and the government entities that contract with it have prevailed in cases brought under both pathways. In a blog post, Flock Safety explains its position that “ALPR cameras sit at fixed and obvious locations and register still images of vehicles at that location and time. They do not follow a vehicle from origin to destination, cover only a small fraction of a city's roads, and provide samples, not a seamless diary of one's movements.” Further, they focus largely on license plate information, and plates are “public by design.” As far as I know, no court has ruled that the use of Flock cameras violates the Fourth Amendment.
However, as they say in commercials for investment services, past performance is no guarantee of future results. Looking at the first pathway, last week, a federal judge in California ordered an evidentiary hearing on a defendant’s motion to suppress. See United States v. Thomas, 2026 WL 2656384 (Sept. 9, 2026) (“Without more information on how Flock works . . . the Court cannot determine whether its use constituted an intrusion into Thomas's constitutionally protected privacy rights and, if so, whether that warrantless intrusion requires suppression of any evidence. . . . The Court therefore grants Thomas’s motion for an evidentiary hearing. [The lead officer] shall be made available for examination by both the parties and the Court regarding his access to the Flock data. The parties shall also present evidence on how a typical Flock search works and on what information is available to police officers through their use of Flock.”).
Looking at the second pathway, the Fourth Circuit is preparing to hear an appeal of Schmidt v. City of Norfolk, 819 F.Supp.3d 492 (E.D. Va. 2026). A federal district court ruled that “on the current record . . . Plaintiffs are unable to demonstrate that Defendants' ALPR system [which included 176 cameras deployed across the city] is capable of tracking the whole of a person's movements” such that it constitutes a search under Jones and Carpenter. The parties’ briefs are in, and dozens of states and organizations (including the North Carolina Association of Chiefs of Police and the North Carolina Sheriffs’ Association) have filed amicus briefs. The Fourth Circuit has tentatively scheduled oral argument for the week of December 8-11. It is shaping up to be a major legal clash, and Supreme Court review is certainly a possibility on the horizon.
One thing to be aware of when thinking about Flock cameras is that North Carolina has a statute that places some limits on how ALPRs may be used. See G.S. 20-183.30 et seq. According to a recent survey by the National Conference of State Legislatures, we are one of only 16 states with statutes addressing the issue.
I hope to post again about Flock cameras as time permits and as further developments warrant.
