Big Brother and the License Plate Data Holding Company: Your Constitutional Right to Privacy on the Open Road


Since the beginning of this year, the Tennessee legislature has been considering a bill that would bring law enforcement surveillance cameras, automated license plate readers (ALPRs), to the state’s interstate highways.[1] They would not, however, be used for traffic enforcement.[2] Instead, these cameras would be used to further big data policing strategies, which have become increasingly common throughout the United States. These surveillance cameras, intended to aid criminal investigations, raise significant privacy concerns, particularly for truckers traveling on Tennessee’s interstate highways.

ALPRs are high-speed, computer-controlled camera systems that can be mounted in a variety of fixed (e.g., streetlights or highway overpasses) and mobile (e.g., mobile trailers or police squad cars) locations. They automatically capture all license plate numbers that come into view along with the location, date, and time. This information is stored in databases for extended periods of time, sometimes even by private companies, that law enforcement can then access and share to determine precisely where a certain vehicle—and in many cases, a certain person— is or was on any given day at any given time.

In gathering this data, ALPRs can provide “an intimate window into a person’s life.”[3] Depending on the size of the ALPR network—i.e., the number of cameras and their geographic locations—law enforcement can track the real-time movements of a vehicle over great distances obtaining information about where the driver lives and works, and any personal affiliations. ALPR data also enable historical investigations allowing the government to “travel back in time to retrace a person’s whereabouts . . . police need not even know in advance whether they want to follow a particular individual, or when.”[4] For example, local police have used ALPRs to grid entire neighborhoods thus tracking the coming and goings of ordinary civilians.[5] Given that some ALPR networks store license plate data for up to five years (although data could easily be stored for even longer), ALPRs allow law enforcement to conduct sweeping dragnets of otherwise innocent people.

The use of ALPRs for the warrantless tracking of individuals has already been subject to litigation. Earlier this year, the Massachusetts Supreme Judicial Court upheld the use of ALPRs used to track an individual suspected of distributing drugs.[6] The court, however, recognized that a more pervasive use of ALPRs could “invade a reasonable expectation of privacy and would constitute a search for constitutional purposes.”[7] Currently pending before the Virginia Supreme Court is a county police department’s practice of indiscriminately scanning and recording the license plate of every passing car—the type of “sweeping randomized surveillance and collection of personal information” that the court previously held would violate Virginia law.[8]

The proposed Tennessee legislation allowing surveillance cameras on interstate highways raises similar concerns. The threat to interstate truckers’ privacy rights is even greater than the use of ALPRs by local law enforcement. As this blog has previously discussed (here and here), just because truck drivers travel on public roads, does not mean they forfeit their constitutional right to privacy. As more states adopt similar policies, interstate truckers might find their life on the road under constant observation.

TCLF welcomes your comments, especially if you have been on the receiving end of an enforcement action from the use of license plate readers.  For more information about ALPRs and how they impact your constitutional right to privacy, please contact:


Gregory R. Reed         (202) 298-4767 

Paul D. Cullen, Jr.      (202) 944-8600 


[1] Keith Goble, Tennessee bill would bring surveillance cameras to interstates, Land Line, June 9, 2020,

[2] TN HB 2110, available at (prohibiting the use of the cameras to enforce “state or local traffic violations” or to “issue citations for such violations.”

[3] See Carpenter v. United States, 138 S. Ct. 2206, 2218 (2018).

[4] Id.

[5] Yael Grauer, Arizona police agencies gather & share license plate data, but few ensure rules are being followed, Arizona Mirror, July 8, 2019,

[6] Commonwealth v. McCarthy, 484 Mass. 493 (2020).

[7] Id. at 505–06.

[8] See Neal v. Fairfax Cnty Police Dep’t, 295 Va. 334, 349 (2018)

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