Automatic License Plate Readers (ALPRs) are becoming increasingly common in law enforcement, raising questions about how and where this technology is deployed. Mounted on various police vehicles, these devices silently collect vast amounts of data, scanning license plates of cars as they pass. But Which Police Cars Scan License Plates, and what exactly are these systems capable of? This article delves into the world of ALPRs, exploring their functionality, the types of police vehicles they are installed on, and the significant privacy implications they present.
What Are Automatic License Plate Readers and How Do They Work?
Automatic license plate readers are sophisticated surveillance tools that use high-speed cameras and computer algorithms to capture and interpret license plate information. These systems record not just the license plate number but also the date, time, and geographic location of every vehicle they scan. Whether attached to police cars patrolling city streets or positioned at fixed locations, ALPRs operate continuously, amassing a considerable amount of data.
Modern ALPR technology utilizes specialized digital cameras and powerful computers to rapidly process numerous license plates. The captured images are instantly converted into text and cross-referenced against “hot lists.” These hot lists contain license plates associated with various categories, ranging from stolen vehicles and wanted individuals to vehicles linked to outstanding parking violations or even individuals on terrorist watch lists. If a scanned license plate matches an entry on the hot list, the system immediately alerts law enforcement personnel.
The Problem with Blanket License Plate Scanning by Police Vehicles
The core concern surrounding ALPRs is that they indiscriminately record every license plate they encounter, regardless of whether a vehicle is suspected of any wrongdoing. As highlighted by the New York State Division of Criminal Justice Services, the sheer volume of data collection is only limited by the number of cars passing within range of the cameras. This mass surveillance captures the movements of countless law-abiding citizens.
Consider the example of the Rhinebeck Police Department, which scanned 164,043 license plates between April and June 2011. Out of this massive number, only eight plates were flagged as being of interest – a minuscule 0.0048% hit rate. This means that 99.99% of the data collected pertained to innocent individuals. The privacy implications of collecting such extensive location data on ordinary people are profound.
The International Association of Chiefs of Police has acknowledged these concerns, cautioning that mobile ALPR units on police cars could potentially record vehicles parked at sensitive locations such as addiction counseling centers, medical clinics, or even sites of political gatherings. This capability could have a chilling effect on fundamental social and political freedoms. Furthermore, without robust privacy safeguards, the data collected by ALPRs can create extensive government databases tracking the movements and habits of entire populations over extended periods. This information can reveal intimate details about individuals, including their associations, routines, and potentially their political or religious affiliations.
To illustrate this point, consider the records obtained from the City of Beacon Police Department. Analyzing just one week’s worth of ALPR data for a single vehicle revealed 24 separate location captures. By using mapping tools, it was possible to pinpoint the car’s presence on Beacon’s Main Street at various times, even indicating overnight parking patterns. This small sample demonstrates the potential for ALPRs to compile detailed profiles of individuals, even when they have committed no offense.
With wider deployment of ALPRs across police car fleets and longer data retention periods, coupled with advanced analytical tools, the technology can paint an extremely detailed and intrusive picture of any individual’s life.
Widespread Use of ALPRs by Law Enforcement Agencies
By 2013, the Division of Criminal Justice Services had funded over 422 ALPR systems throughout New York State, ensuring that every county had at least one. Beyond this, agencies like the New York State Police and the Department of Motor Vehicles also operate these systems.
Density of Automatic License Plate Readers per 100,000 Residents in New York State
Even smaller municipalities have adopted ALPR technology, demonstrating its widespread availability. In New York City, the NYPD operated nearly 500 ALPRs as part of its Domain Awareness System as of 2014, a vast network integrating security cameras, ALPRs, and other surveillance tools. The full extent of the NYPD’s ALPR deployment remains unclear.
Data Access and Sharing: Who Sees Your License Plate Information?
The data collected by ALPRs is often not confined to the agency that directly operates the system. Law enforcement agencies frequently share ALPR data through regional intelligence centers. For instance, the Westchester Intelligence Center facilitates data sharing among various federal, state, and local agencies operating in Westchester County. Similar data-sharing initiatives, like the Albany Crime Analysis Center, exist in other regions.
Furthermore, some law enforcement agencies are partnering with private companies that maintain massive databases of driving history. Vigilant Solutions, a private vendor, offers access to a nationwide database compiled from both private and law enforcement ALPR sources. This database contains billions of records and grows by millions more data points every month. Agreements like the one considered by New York City to access the Vigilant Solutions database significantly expand the surveillance capabilities of law enforcement, allowing them to track vehicle movements across a much broader geographic area and access historical location data.
This access to external databases allows agencies to monitor vehicle locations across apartment complexes, retail areas, and business parks – locations that may fall outside the direct coverage of their own ALPR networks. These systems can also track vehicle locations in real-time, conduct “virtual stakeouts,” and identify vehicles that frequently appear in proximity to one another, further amplifying privacy concerns.
The Need for Clear Policies and Privacy Protections
Due to the absence of comprehensive statewide or federal regulations, policies governing ALPR usage vary widely among local jurisdictions. Alarmingly, many agencies lack adequate policies to protect the collection, use, retention, and sharing of ALPR data. For example, Westchester County, despite operating a significant number of ALPRs, lacked a written policy governing their use and data handling. The county planned to retain location data for a year, even though the vast majority of scans yielded no actionable intelligence. Similarly, Yonkers, with multiple mobile and fixed ALPRs, admitted to indefinitely storing all collected data and lacked a formal usage policy.
Robust privacy protections are crucial to mitigate the chilling effect of this technology and maintain public trust in law enforcement. Local governments should prioritize the adoption of clear and comprehensive policies addressing privacy concerns before deploying and utilizing automatic license plate readers.
For a broader perspective on ALPR deployment across the United States, refer to the ACLU report: You Are Being Tracked: How License Plate Readers Are Being Used to Record Americans’ Movements.
