Some states are pushing back against license plate readers, the book-sized devices mounted on police cars, road signs or traffic lights that police agencies use to collect photos and data to identify stolen cars and wanted or missing persons, reports Stateline. Privacy advocates are concerned about how long police keep the data if the plates don't register an initial hit. In many places there are no limits, so police keep the pictures—tagged with the date, time and location–indefinitely.
Three more states this year have limited law enforcement use of the systems and in some cases banned private companies from using the data, for example, to track down cars for repossession. So far, five states limit how the cameras are used, and the American Civil Liberties Union expects that at least six other states will debate limits in the upcoming legislative session. New Hampshire, Vermont, Maine, Utah and Arkansas have placed limits on their use and data storage.