The San Diego County Sheriff's Department has been using the system since April. Cameras mounted on a patrol cruiser take photos of license plates as the cruiser drives by. The system instantly reads the cameras and warns the deputy if the vehicle has been reported stolen or was involved in a crime.The cameras are used by agencies in 38 states as well as the federal government. Locally, deputies have arrested 16 people since deploying the system on 45 cruisers."Within the first 10 minutes of that LPR being deployed, they found a stolen car," said Sheriff's Department spokeswoman Jan Caldwell.ACLU Executive Director Kevin Keenan told 10News, "Thats a laudable purpose but there are real serious civil liberties concerns and private citizen concerns that we should all worry about."Keenan wants to know what happens to the pictures of vehicles that are not involved in crimes."Your information is still being collected and stored and tracked and that could be abused, not only by law enforcement but by others," he said.Caldwell said, "We're not in the spy business. We're in the business of law enforcement."She said the Sheriff's Department has been collecting information well before the license plate readers were invented."This is nothing that the human eye doesn't capture," she said. "Its the very same thing. It's just faster."Caldwell said the photos are stored for two years with the county's Automated Regional Justice Information System. Then, they are deleted."We only take from that data, that information that is criminal," said Caldwell.The ACLU is not convinced. They said they want safeguards to make sure personal information is not misused."We need to make sure that the accountability mechanisms are in place," said Keenan.