Automated license plate readers (ALPRs) have become a common surveillance tool in the United States, capturing and recording vehicle data across various jurisdictions. These devices, often mounted on poles or police vehicles, collect information such as license plate numbers, vehicle makes and models, and other distinguishing features. The American Civil Liberties Union (ACLU) estimates that there are between 80,000 to 100,000 ALPR cameras deployed nationwide, with significant usage by law enforcement and businesses.
Privacy advocates express concerns about the potential for misuse of the aggregated data collected by ALPRs, which can reconstruct individuals' movements and associations over time. Reports have indicated instances of misuse, including unauthorized searches by law enforcement. However, proponents argue that ALPRs assist in crime-solving and that the data collected is publicly visible.
Legal perspectives on ALPRs vary, with courts generally holding that there is no reasonable expectation of privacy for movements on public roads. Recent court rulings have upheld the use of ALPRs, but some cases suggest that more extensive surveillance could infringe on constitutional rights. For example, the Fifth Circuit Court of Appeals ruled that the use of a limited number of cameras did not constitute a Fourth Amendment search, while a pending case in the Fourth Circuit raises questions about the implications of more extensive camera networks.
In response to growing concerns, legislation such as the proposed "Protection Against Mass Surveillance Act" aims to restrict the use of mass tracking tools by the federal government and states.