Last month, Attorney General Ken Cuccinelli issued an opinion on the use of Automatic License Plate Readers (ALPR) that hit the nail on the head, striking the right balance between law enforcement needs and personal privacy.
ALPRs are cameras mounted on patrol cars or on stationary objects along roads – such as telephone poles or the underside of bridges – that snap a photograph of every license plate that enters their fields of view.  These devices may be used in a number of legitimate ways, for example, to find a stolen vehicle, a vehicle that has been used in a crime, or a vehicle believed to be carrying a kidnapped child.
But there are more disturbing uses for the ALPR.  Imagine, for example, that the police stored every one of the thousands of images captured per minute, accumulating a vast database that could show where a particular car was located on any particular day.  Or suppose an ALPR were mounted outside a controversial religious or political organization, so that police could monitor who regularly parks nearby.
In its interpretation of Virginia law, the AG opinion neatly distinguishes between permissible and impermissible use of the ALPR technology.  As the opinion explains, the use of this technology is governed by the Government Data Collection and Dissemination Act, which regulates the government’s use of personal information.  Information maintained by law enforcement agencies “that deal[s] with investigations and intelligence gathering related to criminal activity” is exempt from the statute.  According to the AG opinion, the “active” use of ALPRs -- that is, using the license plate reader to identify vehicles that have already been determined to be relevant to a criminal investigation – meets that exemption and is permissible for law enforcement.
On the other hand, the “passive” use of ALPRs violates Virginia’s statute.  The Virginia State Police, which made the initial inquiry to the AG’s office, defines this kind of activity as follows:

LPR systems can also be used to collect raw data. Whether the LPR reader is mobile or fixed, the data collected includes the image of the place, the time, date and precise location the license plate in question was captured by the system. This is accomplished passively and continuously. If the LPR system is on, it will capture and store the data for every license in plain view to the public it encounters. On a routine patrol, this may include thousands of license plate numbers and locations  . . . This can, and has been an invaluable tool in developing leads in terrorism investigations and criminal cases.

In other words, the “passive” use of ALPRs creates a comprehensive database of the locations of vehicles that are not suspected of involvement in any wrongdoing.  The police can then “mine” the data for leads in investigations.
The AG opinion explains that this use of ALPRs violates the statute’s requirement that "[i]nformation shall not be collected unless the need for it has been clearly established in advance."  Law enforcement may not simply create a database of vehicle locations, the vast majority of which have nothing to do with any criminal violations.  The fact that doing so might be efficient does not make it right.
Last fall, the ACLU of Virginia participated in a nationwide effort to obtain records from law enforcement agencies to determine how they are using ALPRs.  We will continue to monitor the government’s use of this technology to ensure that it falls within the strictures of the Government Data Collection and Dissemination Act, and does not infringe on the privacy of Virginians.  We will also stand fast against any effort to change the law in response to the AG’s opinion.  It’s not just the AG’s opinion that is correct.  It’s the current law’s careful balance between the privacy rights of Virginians and the needs of law enforcement – a balance that we encourage the legislature to bring to conversations about the use of other new technologies, including cell phone tracking and drones.