Car-tracking cameras, like mobile devices, collect vast swaths of sensitive data.
In 1983, the Supreme Court stated that a person riding in a car on public streets has little to no reasonable expectation of privacy regarding where they go from one location to another. That proposition, increasingly questioned, underpins a nationwide network of more than 144,000 AI-supported cameras that monitor ordinary motorists’ movements across the country billions of times every week.
To date, state and federal courts have almost uniformly rejected Fourth Amendment challenges to automated license plate readers (ALPRs) installed by firms such as Flock Safety. Yet a recent Oklahoma ruling from a federal judge signals a possible shift in how Flock cameras are treated legally, recognizing that they enable “a type of indiscriminate mass surveillance.”
ALPRs are far more advanced than the technology the Court considered in 1983, when it allowed police to monitor a suspect’s car without a warrant using a rogue radio transmitter. Three decades later, the Court held that police should have secured a warrant before placing a GPS tracker on another drug suspect’s vehicle.
The majority in that latter case stressed the physical intrusion involved in installing the tracker. However, five justices supported a different rationale, arguing that GPS tracking intrudes on reasonable privacy expectations by disclosing potentially sensitive information about a person’s historical whereabouts.
That line of reasoning rose to prominence in a 2018 case about mobile-phone location data gathered by cell towers, in which the Court said the Fourth Amendment is implicated because “individuals have a reasonable expectation of privacy in the whole of their physical movements.” The Court reaffirmed that principle this year, extending it to data collected by Google’s Location History feature.
“An individual has a reasonable expectation of privacy in records about his cell phone’s location,” Justice Elena Kagan wrote for the majority, “and police intrude on that constitutionally protected interest when they demand the information.” Following that logic, U.S. District Judge Sara E. Hill concluded this month in the Oklahoma case that people hold a reasonable expectation of privacy in ALPR records, and thus police generally need a warrant to search them.
Those databases hold “information about all vehicles that pass by any network-connected camera at all times,” Hill noted, and can be accessed “on demand.” “Freedom from persistent, dragnet-style surveillance while in public is not a foreign concept in our society, and it is a reasonable expectation that society already accepts,” as reflected in the Supreme Court’s cellphone-related decisions.
Just like cars, cellphones “move in public places where people can see you in plain view,” Hill wrote. “But it becomes constitutionally problematic when law enforcement can indifferently and passively catalog your whereabouts over a long period and then use that information for any purpose whenever it suits them.”
At this stage, Hill’s ruling stands as an outlier. “It appears that nearly every court reviewing the issue to date has determined that ALPR technology use is not a search under the Fourth Amendment because people have no reasonable expectation of privacy in their movements on public roads,” she observed.
For example, last month a federal judge in California found that ALPR database searches are “clearly distinguishable from and less extensive than the ‘near perfect surveillance’ achievable” with cell-site or Location History data. And the day after Hill’s decision, a state judge in California rejected a challenge to San Jose’s Flock camera network, stating “there is no reasonable expectation of privacy in license plate data collected from cameras directed solely at public streets.”
A federal lawsuit involving the same city’s ALPR system, filed by the Institute for Justice last April, remains unsettled. So do challenges to Flock cameras in other municipalities, such as Wichita, Kansas, and Norfolk, Virginia.
Even when courts dismiss such lawsuits, they typically acknowledge that the legal landscape could shift as the number and capability of ALPRs expand. If that happens, it seems likely that Hill will be joined by other judges who recognize the dangers of “indiscriminate mass surveillance.”
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