While license plate readers aren't standard equipment for law enforcement agencies, their use is growing, says the Detroit Free Press. Grant money often helps agencies buy the systems, which can cost $10,000 to more than $20,000. The readers can be affixed to vehicles, bridges, overpasses and at border crossings. With millions of plates being scanned and often stored in databases across the U.S., the growing use of the readers has some civil libertarians and privacy proponents worried about potential abuse, such as tracking a spouse or ex-lover or even tracking the movements of a political opponent.
There are also questions about how effective the devices are and worries about the lack of data retention policies by the agencies using license plate readers — a concern that at least one Michigan lawmaker wants to address through legislation to regulate the devices and limit the amount of time collected data can be kept. “We understand that these are tools that make it easier for law enforcement to do their work,” said Shelli Weisberg of the American Civil Liberties Union of Michigan. “But these technologies are advancing very, very quickly and our laws are not keeping up with the collateral damage of information they gather on everyday citizens.”