Documents released by the American Civil Liberties Union of Virginia confirm that until earlier this year, the Virginia State Police used cameras to track motorists attending political events in 2008. Automated license plate readers (ALPR or ANPR in Europe) are used by law enforcement agencies throughout the country, ostensibly to fight crime by finding stolen cars. A March 18, 2009 state police memo also documents the use of the "Help Eliminate Auto Theft" (HEAT) camera to identify attendees at campaign events for then-Democratic presidential nominee Barack Obama and Republican vice presidential nominee Sarah Palin.

"Palin Rally -- Leesburg, Va.," Sergeant Alvin D. Blankenship wrote in the memo. "The United States Secret Service requested we use a HEAT equipped vehicle at the entrance to a planned rally in Leesburg. The added security offered by having vehicles scanned upon arrival to the event provided the security detail an additional level of security. The vehicle would detect any stolen vehicles attempting to enter the outer perimeter of the event and possibly allow for some record of attendees in the event a serious event occurred during the event."

The agency began using the cameras in 2006, and by 2010 it had a set of ten camera-equipped patrol cars. The devices can photograph every passing vehicle and record the owner's identity in a database that, over time, can provide a searchable map of where an individual has driven for any given date. A March 25, 2010 memo explained the devices produced a significant amount of this type of information.

"It is requested that we purchase a server large enough to store this data to be housed in the Virginia Fusion Center," Captain Steven W. Lambert wrote. "It is requested that we use asset forfeiture funds to purchase the necessary equipment and processes to upload and download the license plate reader data."

The license plate readers demonstrated a high error rate. Four ALPR vehicles used in Fairfax County over the course of five nights in February 2009 scanned 69,281 vehicles. The camera database produced twelve bogus hits and recovered four stolen vehicles, for a recovery rate of 0.6 percent and an error rate of 1.7 percent. Each error can mean an innocent driver is pulled over at gunpoint with a felony stop, as has happened in Europe with fatal consequences.

A November 2009 memo suggests the state police were worried that the public might hear about the department's plans to store license plate data and force the department to shut it down ( view memos, 250k PDF).

"The retention of license plate reader data may result in a negative negative impact on public/legislator's perception of the program," Major Robert L. Tavenner wrote.

It was not until this year that the state police chief asked for an official determination of the legality of the license plate reader program. In a February 13, 2013 ruling, Attorney General Ken Cuccinelli blasted the "passive" use of recording the comings and goings of innocent drivers who are not part of an ongoing criminal investigation.

"Its future value to any investigation of criminal activity is wholly speculative," Cuccinelli wrote. "Therefore, with no exemption applicable to it, the collection of license plate reader data in the passive manner does not comport with the Data Act's strictures and prohibitions, and may not lawfully be done."

A copy of Cuccinelli's ruling is available in a 500k PDF file at the source link below.