We're Asking the Wisconsin Supreme Court to End Warrantless ALPR Searches

The Electronic Frontier Foundation and the ACLU of Wisconsin filed a petition asking the Wisconsin Supreme Court to hold that the state constitution requires a warrant for retrospective searches of automated license plate reader (ALPR) databases maintained by law enforcement in Milwaukee, Racine, Kenosha, and Green Bay. The petition, brought on behalf of the Wisconsin Council of Churches and an individual Green Bay pastor, argues that ALPR systems indiscriminately record where large numbers of people travel - including trips for medical care, recovery meetings, religious services, protests, and political gatherings - and that police routinely collect, store, share, and aggregate those records to reconstruct individuals’ and communities’ movements.

The core legal claim is that warrantless retrospective searches of ALPR data amount to mass surveillance that infringes privacy and expressive-association rights, particularly for religious organizations that facilitate worship, pastoral care, confidential counseling, and community support. This is the challengers’ second major ALPR lawsuit following SIREN v. San Jose; a recent federal decision in Oklahoma described ALPRs as “indiscriminate mass surveillance” and suppressed evidence from a warrantless search. The petition asks the Wisconsin Supreme Court to extend state constitutional protections and prohibit law enforcement from conducting retrospective ALPR searches without a warrant.