The American Civil Liberties Union (ACLU) [advocacy website] announced [press release] on Monday that its affiliates in 38 states had sent letters to local and state police departments asking them to clarify how they use information obtained from automatic license plate readers (ALPRs). ALPRs are cameras mounted near roads and highways that photograph and record license plate numbers. The numbers are electronically interpreted so that police can be alerted when a license plate of interest is seen. In a press release, the ACLU expressed concern about police departments that are gathering and storing information about the travel patterns of all vehicles, regardless of whether they are vehicles of interest, alleging that "responsible deletion of data is the exception, not the norm." The group noted that only two states have passed laws limiting the amount of time police can retain license plate data for cars that do not register as a "hit" in the system. Additionally, the ACLU has requested that the US Departments of Justice, Homeland Security and Transportation [official websites] provide information on how ALPR programs are funded.
Technological advancements allowing the tracking and storage of mass amounts of information has sparked legal controversy in recent years. The US Supreme Court [official website] ruled [JURIST report] in January that the government's attachment of a global positioning system (GPS) device to a vehicle, and its use of that device to monitor the vehicle's movements, constitutes a search under the Fourth Amendment [text]. Last August the ACLU announced that their affiliates were sending approximately 375 requests for information in 31 states to reveal how law enforcement uses location data tracking on cell phones [JURIST report]. Smartphones now come with built-in global positioning systems (GPS), allowing users' movements to be tracked by law enforcement agencies, sometimes prior to having the phone in custody. In January 2011 the Supreme Court of California ruled that law enforcement officers can legally search text messages [JURIST report] on a suspect's cell phone without a warrant incident to a lawful custodial arrest. The California decision represents a split from the US Court of Appeals for the Third Circuit 2010 ruling and a 2009 decision [JURST reports] by the Ohio Supreme Court holding that police must obtain a warrant before searching data stored on a cell phone.