A police car outfitted with an automated license plate reader. In Alexandria, Va., license plate data collected via automated license plate reader is kept for two years, according to the Washington Post.. Wikipedia

There is no expectation of privacy on a public street. That lack of privacy, however, does not give government perpetual, or even extended, rights to store data that details a person's whereabouts without a reason to suspect that a criminal act has occurred.

As The Pilot's Bill Sizemore reported this week, some law enforcement agencies across the region and commonwealth continue to use license-plate readers in a way that former Attorney General Ken Cuccinelli said violates state law.

Cuccinelli's opinion, issued last year in response to a query from Virginia State Police Col. W. Steven Flaherty, distinguished between active and passive collection of data.

Active collection involves law enforcement officials searching for a particular suspect and sifting through data in real time, or very near to real time, to find him. It's a responsible use of technology that protects the public and maintains respect for civil liberties.

Passive collection involves storing license-plate information and building a database of personal information, including a person's whereabouts and daily patterns. It conflicts with principles that informed the Fourth Amendment.

As Cuccinelli wrote, passive collection also conflicts with a provision of the state Government Data Collection and Dissemination Practices Act that notes "[i]nformation shall not be collected unless the need for it has been clearly established in advance."

"Its future value to any investigation of criminal activity is wholly speculative."

In response, the Virginia State Police now dump data collected through license-plate readers after 24 hours, Sizemore reported. Virginia Beach does, too. Suffolk effectively dropped its license-plate data-collection effort.

But Portsmouth holds on to data for 72 hours, while "Norfolk, Chesapeake and the Chesapeake Bay Bridge-Tunnel police - who operate a stationary camera on the bay crossing - keep it for 30 days," Sizemore reported.

Collecting this kind of data for such an extended period is unnecessary. Worse, it permits an overreach of government that, as the attorney general properly noted a year ago, directly conflicts with a law designed to balance law enforcement and personal privacy.

Proponents' claims that the technology is indispensable in solving and preventing crimes are undermined by the experiences of police in Newport News and Hampton, where officials dropped their license-plate reader programs even before the attorney general issued his opinion.

"We just weren't seeing the results," Newport News Police spokesman Lou Thurston told Sizemore.

That suggests that the utility of this technology is, at best, debatable. Its effect on society, however, is incompatible with the right to be free from unreasonable searches by government. The data storage should stop.

©2014 The Virginian-Pilot (Norfolk, Va.)