The American Civil Liberties Union of Maryland (ACLU) on Monday requested information about how law enforcement agencies use data compiled by automatic license plate readers, according to a release from the group.

The ACLU's national office and affiliates in 38 states made similar requests Monday.

In Maryland, law enforcement agencies are using more than 320 ALPRs that are linked to the Maryland Coordination and Analysis Center (MCAC), Maryland's "fusion center," where the data is stored.

"Automatic license plate readers make it possible for the police to track our location whenever we drive our cars and to store that information forever," said Catherine Crump, an ACLU staff attorney. "The American people have a right to know whether our police departments are using these tools in a limited and responsible manner, or whether they are keeping records of our movements for months or years for no good reason."

The readers are used in a variety of ways, from helping law enforcement officials to yank dangerous criminals from the state's streets to assisting police in locating missing or lost children or elderly people, reports the Baltimore Sun.