Police Car Scanning License Plates: How ALPR Technology Tracks Vehicles and Raises Privacy Concerns

Automatic License Plate Readers (ALPRs) are becoming an increasingly common tool in law enforcement. Mounted on police cars or fixed in strategic locations, these devices automatically scan the license plates of every vehicle that passes by. But what exactly are Police Car Scanning License Plates, and what are the implications for drivers and their privacy? This article delves into the technology behind police car license plate scanning, exploring how it works, who uses it, and the growing concerns surrounding data collection and potential misuse.

Understanding Automatic License Plate Readers in Police Cars

Police car scanning license plates, more technically known as mobile Automatic License Plate Readers (ALPRs), are sophisticated systems designed to capture and process license plate information in real-time. These systems utilize high-speed cameras and advanced software to photograph license plates and instantly convert the images into readable text. At a minimum, each scan records the license plate number, along with the date, time, and geographical location of the vehicle.

Modern police car scanning systems are incredibly efficient. They employ “specialized digital cameras and computers to quickly capture large numbers of photographs of license plates, convert them to text and compare them quickly to a large number of plates of interest.” These “plates of interest” are compiled into a “hot list,” which is pre-loaded into the ALPR system. This hot list can include data from various sources, such as databases of stolen vehicles, wanted persons, or vehicles associated with outstanding parking violations. When a scanned license plate matches a plate on the hot list, the system immediately alerts law enforcement officers.

The Growing Privacy Concerns Surrounding Police Car License Plate Scanning

While police car scanning license plates can be a valuable tool for identifying vehicles linked to criminal activity, a significant concern arises from the fact that ALPRs record every license plate they scan, regardless of whether the vehicle is of interest or not. According to the New York State Division of Criminal Justice Services, the technology is so advanced that “the number of license plates that can be read is limited only by the number of vehicles passing the cameras.” This means vast amounts of data are collected on ordinary citizens who are not suspected of any wrongdoing.

Consider the example of the Rhinebeck Police Department, which scanned 164,043 license plates over a three-month period. Of these, only eight were flagged as being on a hot list – a success rate of just 0.005%, or a 99.99% “failure rate” in terms of identifying plates of interest. This massive collection of data on innocent individuals raises serious privacy implications.

The International Association of Chiefs of Police has acknowledged these concerns, cautioning that “mobile LPR units could read and collect the license plate numbers of vehicles parked at addiction counseling meetings, doctors’ offices, health clinics, or even staging areas for political protests.” This capability can create a “chilling effect on social and political activities,” as people may be less inclined to engage in activities if they believe their movements are being monitored and recorded.

Furthermore, without robust privacy safeguards, the data collected by police car scanning license plates can be stored indefinitely and even shared with other agencies. This creates the potential for a comprehensive government database tracking the movements of individuals, revealing sensitive information about their habits, associations, and even potentially their political or religious affiliations.

An example from the City of Beacon Police Department illustrates this point. When the NYCLU requested ALPR data, records for just one week of scans for a single car revealed 24 separate location captures. Analysis using tools like Google Maps showed the car’s presence on Beacon’s Main Street at various times, including overnight parking. Even this limited data paints a detailed picture of the vehicle owner’s movements and habits.

With more extensive data collection over longer periods and across multiple ALPR systems, an incredibly detailed and potentially intrusive picture of an individual’s life can be assembled, even if they have committed no crime.

Widespread Use of Police Car Scanning License Plates

Police car scanning license plate technology is not limited to large cities or federal agencies. As of 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. The New York State Police and the Department of Motor Vehicles also utilize these devices.

Density of Automatic License Plate Readers per 100,000 Residents in New York State

Even small towns and villages are equipped with police car scanning license plates. The NYPD, as of 2014, operated nearly 500 ALPRs within its Domain Awareness System, a vast network of surveillance technologies. The extent of ALPR deployment highlights the pervasive nature of this technology in modern policing.

Data Access and Sharing Networks

The data collected by police car scanning license plates is not always confined to the local jurisdiction that collected it. Law enforcement agencies often participate in data-sharing networks, increasing the reach and scope of surveillance. In Westchester County, for example, various federal, state, and local agencies collaborate through the Westchester Intelligence Center to share ALPR data. Similarly, the Albany area has established the Albany Crime Analysis Center for data sharing.

Furthermore, some agencies are partnering with private companies like Vigilant Solutions, which maintains a massive nationwide database of license plate data collected from both private and law enforcement sources. Vigilant Solutions’ database contains billions of records and is constantly growing. Access to such databases allows law enforcement to track vehicle movements across vast geographical areas and historical timeframes, significantly expanding their surveillance capabilities. The NYPD, for instance, has contracted with Vigilant Solutions to access this extensive database.

The Need for Clear Policies and Privacy Protections

The widespread deployment of police car scanning license plates and the potential for extensive data collection underscore the urgent need for clear policies and robust privacy protections. Currently, in many areas, there are no statewide regulations governing the use of ALPRs. Policies vary widely from locality to locality, and many jurisdictions lack adequate safeguards regarding data collection, use, sharing, and retention.

Westchester County, despite having a high concentration of ALPR systems, initially lacked a written policy on their use and intended to retain collected data for a year, even though the vast majority of scans yielded no actionable intelligence. Yonkers, with multiple mobile and stationary ALPR units, admitted to indefinitely storing all collected data and also lacked a formal policy.

The absence of clear policies and limitations on data retention and sharing poses a significant threat to privacy. Establishing robust privacy protections is crucial to mitigate the chilling effect of this technology and maintain public trust in law enforcement. Local governments must prioritize the adoption of comprehensive policies that address privacy concerns before implementing and utilizing police car scanning license plates.

For further information on the broader use of automatic license plate readers, see the ACLU report: You Are Being Tracked: How License Plate Readers Are Being Used to Record Americans’ Movements.

References

1. New York State Division of Criminal Justice Services, License Plate Reader Suggested Guidelines, Jan. 2011, p. 6.
2. Id.
3. Id.
4. Id. at p.7.
5. Id. at p.6.
6. Rhinebeck Police Department FOIL Response: Quarterly License Plate Reader Progress Report Apr.-Jun 2011.
7. International Association of Chiefs of Police, Privacy Impact Assessment Report for Utilization of License Plate Readers (Sept. 2009), p. 2.
8. Id. at p.13.
9. New York State Division of Criminal Justice Services (DCJS) FOIL Response (Aug. 27, 2013).
10. 2010 Census of Population and Housing.
11. Testimony of Deputy Commissioner of Intelligence and Counterterrorism John J. Miller, NYPD, Nov. 12, 2014.
12. Ardsley Village FOIL Response; Bedford Town FOIL Response.
13. Colonie PD FOIL Response.
14. Vigilant Solutions Scope of Work.
15. DCJS FOIL Response.
16. Westchester County Department of Public Safety FOIL Response.
17. Id.
18. City of Yonkers FOIL Response.
19. Id.