Automated license-plate-recognition systems (ALPRs) mounted in patrol cars are capable of processing 1,500 license plates a minute, capturing a vast amount of data about the movements of both criminals and law-abiding citizens. For police, ALPRs allow them to solve auto-theft cases, pick up wanted felons or monitor the movements of sexual predators. But privacy advocates fear the collected data may be mined for other purposes. For example, one side of a divorce case could potentially look through toll-plaza records for circumstantial evidence of adultery. […]
What concerns the American Civil Liberties Union and others is the accumulation and storage of the vast amount of data collected by the scanners. “We were disturbed when we began to see the technology used as a generalized surveillance tool,” says Jay Stanley, a spokesman for the ACLU. Privacy advocates worry, for example, that the data could be used to examine who attended a political event or protest.