I’ve written about the privacy and civil liberty issues connected with the use of license-plate-scanner recognition technology to gather and record drivers’ movements. Often, we don’t know what the restrictions are on the collection and use of the data. (See a previous post for more information on the camera surveillance technology.) The American Civil Liberties Union has released a new report(pdf) on license-plate readers and how they are used as surveillance devices. The ACLU says in its press release: “The study found that not only are license plate scanners widely deployed, but few police departments place any substantial restrictions on how they can be used. The approach in Pittsburg, Calif., is typical: a police policy document there says that license plate readers can be used for ‘any routine patrol operation or criminal investigation,’ adding, ‘reasonable suspicion or probable cause is not required.’ While many police departments do prohibit police officers from using license plate readers for personal uses such as tracking friends, these are the only restrictions. As New York’s Scarsdale Police Department put it in one document, the use of license plate readers ‘is only limited by the officer’s imagination.'”
The ACLU says its report “has over a dozen specific recommendations for government use of license plate scanner systems, including: police must have reasonable suspicion that a crime has occurred before examining the data; unless there are legitimate reasons to retain records, they should be deleted within days or weeks at most; and, people should be able to find out if their cars’ location history is in a law enforcement database.”
Here’s an excerpt from “You Are Being Tracked: How License Plate Readers Are Being Used to Record Americans’ Movements.”
License plate reader systems typically check each plate number against “hot lists” of plates that have been uploaded to the system and provide an instant alert to a law enforcement agent when a match or “hit” appears.
License plate readers would pose few civil liberties risks if they only checked plates against hot lists and these hot lists were implemented soundly. But these systems are configured to store the photograph, the license plate number, and the date, time, and location where all vehicles are seen — not just the data of vehicles that generate hits. All of this information is being placed into databases, and is sometimes pooled into regional sharing systems. As a result, enormous databases of motorists’ location information are being created. All too frequently, these data are retained permanently and shared widely with few or no restrictions on how they can be used.
The implementation of automatic license plate readers poses serious privacy and other civil liberties threats. More and more cameras, longer retention periods, and widespread sharing allow law enforcement agents to assemble the individual puzzle pieces of where we have been over time into a single, high-resolution image of our lives. The knowledge that one is subject to constant monitoring can chill the exercise of our cherished rights to free speech and association. Databases of license plate reader information create opportunities for institutional abuse, such as using them to identify protest attendees merely because these individuals have exercised their First Amendment-protected right to free speech. If not properly secured, license plate reader databases open the door to abusive tracking, enabling anyone with access to pry into the lives of his boss, his ex- wife, or his romantic, political, or workplace rivals.