(Picture credit Connor Klocke)
As debate over the use of Flock cameras and similar automated license plate reader (ALPR) technology heats up across Nebraska, policymakers would be wise to take heed of the Fourth Amendment as an essential guide for their decision-making. The applications of ALPR technology may be expedient, but their convenience does not repeal the constitutional limits of the Fourth Amendment any more than improved firearms repealed those of the Second Amendment.
When the Second Amendment was ratified in 1791, a single-shot flintlock pistol was the common sidearm. Today, the standard sidearm is a Glock. No serious person would put forth the argument that the Second Amendment’s guarantee shrinks to fit only the technology of 1791. It is commonly understood that the amendment protects a principle: the right to keep and bear arms for self-defense. That principle travels forward even as the tools change.
The Fourth Amendment deserves the same treatment. Like the Second Amendment, it also protects a principle: that the people are to be protected from unreasonable searches. Though the initial application of this principle protected against unreasonable physical searches, a good faith application in the modern era would also protect against unreasonable technologically enhanced searches. The protection of this principle today therefore calls ALPR technology as currently utilized into serious question.
ALPRs, of which Flock cameras are the most well-known variety, have been deployed in municipalities throughout the country in recent years. Nebraska has been no exception.
There are hundreds of ALPRs across the state, on street corners, intersections, and major thoroughfares, surveilling every passing vehicle and logging their license plates, locations, and the time they were seen. Once logged, this information is stored in a searchable database. A simple search query can then reconstruct the comings and goings of a vehicle long after the data was collected.
Proponents of ALPR technology contend that license plates on public roads are fair game, and that a single query spanning a short window of time does not amount to a search under the Fourth Amendment. But this argument is weaker than it sounds, especially in light of this June’s Supreme Court decision in Chatrie v. United States.
In Chatrie, the Court ruled 6-3 that when police obtained cell-phone location history from Google through a geofence warrant, they conducted a search under the Fourth Amendment. Writing for the majority, Justice Kagan held that people retain a reasonable expectation of privacy in their cell-phone location data, even when that data is held by a third party and even when the window of surveillance is brief — in Chatrie, just two hours.
Chatrie builds on Carpenter v. United States, which held that police need a warrant for historical cell-site data because such data, aggregated over time, paints an intimate picture no single data point ever could. In the legal world, this is referred to as the “mosaic theory,” the core concept of which is that trivial pieces of information become far more revealing, and deserving of heightened protection, once compiled and made searchable.
While the Supreme Court has yet to issue any rulings directly implicating ALPRs, the logic of Chatrie and Carpenter reaches them just the same. Flock cameras, much like geofencing technology, harvest location information through seemingly innocuous and virtually unavoidable means, then compile this data into a searchable record.
The technical methods of data collection may differ, but the underlying constitutional concern is the same: an individual’s location tracked over time, stored, and aggregated for possible query later reveals far more than any single sighting ever could and thus merits heightened protection.
Critics may counter that license plates are publicly viewable by design, and thus ALPR plate scans are categorically distinct from cell phone location data. License plates are, indeed, by nature meant to be seen. After all, the whole point of requiring them is to give law enforcement a guaranteed, identifiable data point for a specific vehicle at a specific moment.
But this misses the point. The concern over ALPRs is not about isolated glimpses of plates in public view. It is about what happens once thousands of lawful glimpses are timestamped, geotagged, and compiled into a permanent, searchable record controlled by an unaccountable third party.
Nebraska policymakers need not wait for the Supreme Court to conclusively rule on ALPRs, however. The Fourth Amendment establishes a constitutional floor, not a ceiling for responsible policymaking.
Even if courts ultimately determine that some uses of ALPR data are permissible without a warrant, Nebraska lawmakers and local governments remain free to recognize that the ability to reconstruct a person’s movements over days, weeks, or months presents a privacy concern fundamentally different from an officer seeing a license plate on the road.
Policymakers have a duty to account for public safety. That duty includes crafting policy that keeps the public safe from government overreach. Those charged with this duty across the state of Nebraska ought to account for this nuance when deciding whether Flock belongs in their communities. The safest option is to block Flock.
— Connor Klocke is a law student at the University of Nebraska College of Law. He has interned for Governor Jim Pillen and three members of Congress.