In August of 2015, shortly after the ACLU released a groundbreaking report, the ACLU of Illinois and the Chicago Police Department (CPD) reached a landmark settlement agreement to reform the practice of investigatory street stops known as “stop and frisks.” The City of Chicago agreed to take steps to ensure that CPD policies and practices comply with the Fourth Amendment, which protects against unreasonable searches and seizures, and the Illinois Civil Rights Act, which requires that government policies do not have a racially disparate impact.
https://www.aclu-il.org/en/campaigns/stop-and-frisk