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Automated License Plate Readers: Background and Legal Issues

Congressional Research Service · July 21, 2025 · United States

CRS In Focus for Congress: how mobile and fixed ALPRs work, hot-list matching, and the unsettled Fourth Amendment question. No federal appellate court has decided whether querying an ALPR database is a search. Trial courts have often found no reasonable expectation of privacy in plates in plain view, while warning Carpenter-style mosaic issues could still bite at scale.

Why it is in the file

The legal-status cite from a nonpartisan congressional shop. Key line: no federal appellate holding yet; Carpenter has not been cleanly extended to ALPR databases.

Open source

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