US number plate scanners track ordinary drivers
American law enforcement agencies are using number plate scanners designed to track down criminals to build databases detailing the whereabouts of millions of US drivers, the American Civil Liberties Union says.
The ACLU's new report, released on Wednesday, summarised the advocacy group's 2012 investigation into the way law enforcement agencies collect and store data from number plate readers, which are typically installed beside roads or on police cars.
The scanner systems quickly photograph passing cars and analyse their number plates to check against lists of cars sought by law enforcement in continuing investigations.
The ACLU's review of documents from 38 states and Washington found the systems were also often used to log databases of information - photographs, plate numbers, time and location - gathered by the cameras over months or years from all passing cars, not just selected ones.
"I think (people) fail to appreciate the tremendous scope of tracking, which can occur using licence plate readers," said Catherine Crump, the main author of the report. "We've never before lived in a society where you couldn't go out the door without the government knowing where you went."
The report, based on documents ACLU affiliates received from police departments via 587 freedom of information requests, gives new fodder to the growing debate over the scope of US government surveillance. Law enforcement authorities say gathering data on the comings and goings of US drivers is a valuable resource for speedier investigations, including future ones.
"Only a fraction of 1 per cent" of number plate scans are hits for cars of interest to law enforcement, the report says.