Downers Grove (IL) Police Department Automated License Plate Readers

The Downers Grove Police Department uses automated license plate readers (“ALPR”).  ALPRs are high-speed cameras that scan their surroundings for vehicle license plates.  ALPR cameras can be fixed-location (e.g. mounted on poles) or vehicle-mounted. When an ALPR camera scans a license plate, it records an image of the plate called a “detection” or “plate scan.” The ALPR system’s software then uploads these images of license plates to a centralized database hosted and managed by a private ALPR database service provider. The detections in the database include the date, time, and location of the detection, as well as a photograph of the vehicle and its plate. Law enforcement agencies can enter license plate numbers into the database and the database will return a list of such all instances in which its ALPR cameras detected that plate. Law enforcement agencies can also elect to make their detections accessible to other law enforcement agencies. Law enforcement agencies can also create lists of wanted license plates (“hot lists”) in the database and the database will alert that agency of all future detections of that plate (“hits”) when they occur.  Even if a law enforcement agency does not operate its own ALPR cameras, it can still subscribe to a ALPR database service to conduct searches of detections or receive hits for vehicles of interest to their investigations. 

Vigilant Solutions is the most prolific provider of ALPR database access services for law enforcement.  Vigilant’s database of ALPR detections is called the National Vehicle Location Service (“NVLS”).  Vigilant’s law enforcement clients access this database via Vigilant’s software and online portal, called the Law Enforcement Archival Reporting Network (“LEARN”).  Vigilant, a subsidiary of Chicago-based Motorola Solutions, also produces and sells ALPR hardware.

In 2018, DGPD entered into a contract with Vigilant Solutions for access to Vigilant’s LEARN/NVLS database.[1]  This contract has been extended through June 2021.[2]  In 2020, DGPD paid Vigilant Solutions $8590 for database access.[3]  DGPD also appears to operate its own ALPR cameras.[4]  In 2019, DGPD’s ALPR cameras recorded 489,776 detections, of which 0 were hits for a hit ratio of 0%.[5]  DGPD shares and receives detection data and hot lists with numerous other law enforcement agencies.[6]  While DGPD previously shared its detection data with U.S. Immigration and Customs Enforcement, DGPD discontinued this practice in 2019 in response to a demand from the American Civil Liberties Union of Illinois.[7]  DGPD submitted over 500 license plate queries to the LEARN system in 2019.[8]  DGPD has an official ALPR policy which appears to be based on the Commission on Accreditation for Law Enforcement Agencies’ (“CALEA”) standard 41.3.9.[9]


[1] Downers Grove-Vigilant Solutions Software Service Program Agreement, available at: https://beta.documentcloud.org/documents/20422921-downers-grove-il-police-vigilant-solutions-alpr-software-service-agreement

[2] Id.

[3] Downers Grove Vigilant Solutions Invoices, available at: https://beta.documentcloud.org/documents/20422922-downers-grove-il-police

[4] Id., at p. 5.  

[5] Downers Grove LEARN Dashboard Hit Ratio Report 2019, available at: https://beta.documentcloud.org/documents/20422920-downers-grove-il-police-alpr-hit-ratio-2019

[6] Downers Grove LEARN Agency Data Sharing Report 2020, available at: https://beta.documentcloud.org/documents/20422919-downers-grove-il-police-alpr-agency-sharing-2020

[7] See, ACLU of Illinois, “ICE TARGETING IMMIGRANTS BASED ON AUTOMATIC LICENSE PLATE READER (ALPR) DATA SUPPLIED BY POLICE DEPARTMENTS IN ILLINOIS” (March 13, 2019), available at: https://www.aclu-il.org/en/press-releases/ice-targeting-immigrants-based-automatic-license-plate-reader-alpr-data-supplied

[8] Downers Grove Police Department, “Audit Records Viewed List Report” (2019), available at: https://beta.documentcloud.org/documents/20422924-downers-grove-il-police-alpr-viewed-records-2019

This data appears incomplete as it covers only approximately six months from June 2019 – December 2019 and terminates at exactly 500 queries.

[9] Downers Grove Written Directive 41.3.9, available at: https://beta.documentcloud.org/documents/20422918-downers-grove-il-police-alpr-policy  

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Elgin Police Department Automated License Plate Readers

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Calumet City (IL) Police Department Automated License Plate Reader Program