A license plate reader is seen mounted on the trunk of a Metropolotian Police Department car in Washington. It records license plates and rapidly checks a database of stolen or wanted cars. In Northern Virginia, police have ignored an attorney general’s opinion regarding the images that are collected. (Paul J. Richards/AFP/Getty Images)

A state delegate from Prince William County filed legislation Friday that would formally prohibit Virginia law enforcement agencies from storing license plate information in databases if it is not directly linked to a criminal or terrorism investigation.

The bill by Del. Richard L. Anderson (R-Prince William) seeks to codify an advisory opinion issued last year by then-Attorney General Ken Cuccinelli II, who said that the state’s “Data Act” prohibited keeping data from license plate readers unless it was “clearly established in advance” to be related to criminal activity.

The Washington Post reported Friday that after Cuccinelli issued his opinion last February, all of the major police departments in Northern Virginia consulted with their attorneys and decided to continue keeping the data. In Alexandria, the data are kept for two years; in Fairfax and Loudoun counties, one year; and in Prince William and Arlington counties, six months.

License plate readers, mounted on the back of police cruisers, can snap dozens of photos per minute of license plates and then check the numbers against a “hot list” of stolen cars and people wanted or missing. Police nationwide and locally use them daily, driving through neighborhoods and parking lots in hopes of solving crimes.

But the readers create vast amounts of data with the time, date and exact location of every license plate snapped. Civil liberties activists argue that this enables the government to track people’s movements. Police say they can use the data to investigate crimes which aren’t reported or discovered immediately or to connect the pieces in a series of offenses by reviewing vehicles at the scene of earlier crimes.

Do they have your photo?

In 26 states, police often can find out who you are based on your facial image, even if you've never been arrested for any crime.

Anderson said he filed the bill “to protect people’s civil liberties. I’m all for letting law enforcement do their job, but I just don’t think storing this data . . . necessarily enhances their capacity.”

Anderson’s bill would amend Virginia Title 2.2-3800 to include “vehicle license plate number” in the definition of “personal information” and add a section that says police agencies “shall not use any technology to collect or maintain personal information in a passive manner where such data is of unknown relevance and is not intended for prompt evaluation.”

A spokeswoman for the Virginia Association of Chiefs of Police, which supports the database practice, did not respond to a request for comment. An aide to state Sen. J. Chapman “Chap” Petersen (D-Fairfax) said he will file a companion bill in the Senate next week.

The bill also amends Title 52-48, which creates the Virginia Fusion Intelligence Center — an anti-terrorism law enforcement cooperative — to prohibit gathering “personal information collected without a warrant.”