How we analyzed the Flock license plate reader data

To examine how Florida Highway Patrol used automatic license plate reader technology from Flock Safety during the state’s recent immigration crackdown, we conducted an analysis of a national database of more than 4 million Flock searches. Below, we outline the methodology behind our findings.

The search logs came from public record requests filed with the Danville, Illinois, Police Department by researchers who requested anonymity due to fears of retaliation. The researchers requested similar records from multiple law enforcement agencies but had not received records from others when 404 Media first reported on this data. 

Automatic license plate readers do not store information on people but on vehicles. Flock cameras automatically scan and capture passing vehicles’ license plate details — creating a record of their locations at specific times, which law enforcement agencies can use in investigations.

By accessing the technology, a law enforcement officer taps into a network of tens of thousands of Flock cameras across the country, including those under contract with other law enforcement agencies. The Danville files therefore give a window into other departments’ use of the system, including Florida Highway Patrol.

When running a license plate search in Flock’s network, officers usually enter a “reason” for the query. That reason goes into the search log. Other details, such as the agency name, officer name and time of search, are also captured. To review immigration-related Flock usage by law enforcement in Florida, Suncoast Searchlight independently downloaded the Danville files, merged and deduplicated the logs, filtered for Florida agencies and analyzed the “reason” field.

The keywords we searched for were “dhs,” “homeland,” “border patrol,” “cbp,” “ice” and “immigration.” Irrelevant variations of these keywords were excluded, such as words like “police” that contain “ice.”

By analyzing the frequency, dates and agencies of such searches, we found that Florida Highway Patrol used those search terms much more than other Florida law enforcement organizations and especially during the immigration crackdown called Operation Tidal Wave in April.

As part of our fact checking process, a data journalist outside our organization who did not work on this story recreated our analysis and verified the numbers.

Kara Newhouse is an investigative data reporter for Suncoast Searchlight, a nonprofit newsroom of the Community News Collaborative serving Sarasota, Manatee, and DeSoto counties. Learn more at suncoastsearchlight.org.