EFF, ACLU Challenge Warrantless ALPR Searches in Wisconsin
EFF and ACLU ask Wisconsin Supreme Court to end warrantless ALPR database searches.
Why it matters: This case could reshape surveillance laws and enforce stronger privacy protections for Wisconsin drivers, impacting local law enforcement practices statewide.
- EFF and ACLU filed the petition on October 14, 2026, representing Wisconsin Council of Churches and a Green Bay pastor.
- They argue ALPRs track private activities like medical visits, religious services, and protests without warrants.
- Wisconsin Assembly Bill 576 to require warrants for ALPR data searches failed in March 2026.
- A California court recently dismissed a similar challenge, ruling no privacy expectation on public roads.
On October 14, 2026, the Electronic Frontier Foundation (EFF) and the American Civil Liberties Union (ACLU) of Wisconsin petitioned the Wisconsin Supreme Court to declare that warrantless retrospective searches of Automated License Plate Reader (ALPR) databases violate the state constitution. The petition challenges law enforcement use of ALPR technology in Milwaukee, Racine, Kenosha, and Green Bay, alleging it infringes on privacy rights by monitoring vehicles engaged in private activities.
The petition, supported by the Wisconsin Council of Churches and an individual pastor, highlights concerns that ALPR systems record movements of drivers seeking medical care, attending religious services, participating in protests, and other sensitive activities. According to the EFF and ACLU, this surveillance occurs without judicial oversight, raising constitutional issues.
Prior legislative efforts to regulate ALPR use in Wisconsin stalled when Assembly Bill 576 failed on March 23, 2026. The bill aimed to limit ALPR searches and mandate a warrant for data access, but did not pass the Senate. Meanwhile, the Milwaukee Police Department operates three ALPR systems and has recently implemented new security safeguards to prevent misuse and enhance privacy protections.
Nationally, the debate over ALPR privacy continues. In October 2026, a California trial court dismissed SIREN v. San Jose, a case challenging warrantless ALPR data searches, ruling that individuals have no reasonable expectation of privacy when driving on public roads. The EFF criticized the ruling and plans to appeal, signaling ongoing legal battles over ALPR surveillance.
This Wisconsin petition could set a precedent in how courts balance law enforcement interests with privacy rights in the digital age, possibly requiring warrants for retrospective ALPR data searches and limiting warrantless mass surveillance.
By the numbers:
- March 23, 2026 — Wisconsin Assembly Bill 576, requiring warrants for ALPR searches, failed to pass.
- October 14, 2026 — EFF and ACLU filed the petition with the Wisconsin Supreme Court.
- Milwaukee Police Department operates three ALPR systems.
Yes, but: A recent California court ruling rejected similar privacy claims regarding ALPR data, finding no reasonable expectation of privacy on public roads.
What's next: The Wisconsin Supreme Court will decide whether warrantless searches of ALPR data violate state constitutional protections, potentially setting statewide surveillance standards.