A state agency ruled Monday that vehicle location data derived from police license plate readers across Minnesota should not be accessible to the public.

The ruling by the Department of Administration comes three months after Minneapolis Mayor R.T. Rybak asked the state to reclassify the data, which the Star Tribune first reported was public by default last August. Monday's classification expires in 2015, but legislators are working on measures to make the information permanently private.

License plate readers, which are mounted on police squad cars, bridges and elsewhere, store records on every vehicle they spot on the road. Their primary purpose is to help police identify criminals in real time, but they also log loads of information on law-abiding citizens.

Rybak asked for the data to be reclassified after Minneapolis police received many requests for data on the whereabouts of specific vehicles following Star Tribune coverage of the issue. The reclassification request made the data temporarily nonpublic. It came a day after the city handed over more than 2 million plate scans to several requesters.

The Department of Administration ruled Monday that the following data generated by license plate readers would be private: plate numbers; times, dates and locations of vehicle scans, and vehicle photos.

Legislators, meanwhile, are grappling with how to regulate license plate readers beyond merely the data classification issue. Sen. Scott Dibble, DFL-Minneapolis, originally sponsored a bill mandating that police immediately destroy location data on noncriminals.

Law enforcement groups, noting that it can take time to identify suspects after a crime, successfully pushed for a retention time of 90 days in the Senate bill.

Dibble's bill also said police must disclose where the readers are installed; Minneapolis police refuse to disclose the location of their stationary readers. This provision was eliminated under pressure from law enforcement groups.

The modified bill requires police to disclose the times of day that the readers collect data and how many vehicles they scan. Privacy advocates have pushed for shorter retention times and more transparency to ensure that police are held properly accountable for their use of the technology.

The House companion to Dibble's bill, sponsored by Rep. Mary Liz Holberg, R-Lakeville, will get a hearing in the Civil Law committee Wednesday.

Eric Roper • 612-673-1732