NEW YORK, July 31 (Reuters) - The New York Civil Liberties Union has asked local police departments for information on data captured by automatic license plate readers, part of a nationwide effort launched this week.

Affiliates of the American Civil Liberties Union in 38 states and Washington filed freedom of information requests with local and state authorities for details on whether law enforcement is preserving data on drivers' movements and locations for longer than necessary.

The requests for information represent the group's latest attempt to protect individual privacy against the growing influence of tracking technology on law enforcement efforts. Last year, the ACLU compiled data on how police departments were using location data from mobile phones.

"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," ACLU staff attorney Catherine Crump said in a statement.

Automatic license plate readers are cameras mounted either on patrol vehicles or alongside roads that take photographs of every license plate that goes by. According to the ACLU, each photo is typically stamped with the date, time and location and sent to a database. Officers are notified if a plate scores a "hit," matching a license plate that police are searching for.

The photographs can be helpful in solving certain crimes, such as motor vehicle theft. But the ACLU is concerned that the data may be kept for too long and pooled in state or national databases, allowing law enforcement to keep tabs on individuals' whereabouts without a warrant.

"It's a balancing of interests, which sounds to me as if it will eventually be decided by our court system," said Bruce Lawlor, the director of the Center for Technology, Security and Policy at Virginia Tech.

PRIVACY CONCERNS

In New York, the NYCLU is seeking records from law enforcement agencies in the Lower Hudson Valley, Suffolk County, Nassau County and Western New York, as well as the state's division of criminal justice statistics.

According to the ACLU, only New Hampshire and Maine have statutes that regulate the use of automatic license plate readers.

The intersection of privacy, law enforcement and tracking technology has drawn increasing attention from civil liberties groups in recent years.

In July, Edward Markey, a Massachusetts Congressman, released data showing that U.S. law enforcement agencies made 1.3 million requests for customers' phone records from mobile phone carriers last year.

And in January, the Supreme Court ruled that police cannot place a global positioning satellite device on a car to track a suspect's movements without a warrant, in a case (U.S. v. Jones)that had raised concerns among privacy advocates.

The ACLU also filed freedom of information requests this week with the Justice, Transportation and Homeland Security departments seeking details on how those departments fund automatic license plate readers and use the collected data.

(Reporting by Joseph Ax)

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