ACLU and EFF File Lawsuit Against San Jose Over Warrantless ALPR Database Searches

The ACLU of Northern California and the Electronic Frontier Foundation filed a lawsuit against the City of San Jose and its police department in November 2025, challenging the constitutionality of warrantless searches of the city's automated license plate reader database.

The complaint, filed in Santa Clara County Superior Court, centers on San Jose's practice of allowing officers to query its ALPR database -- which contains records on millions of vehicle movements -- without a warrant, judicial oversight, or individualized suspicion.

"This is one of the largest unregulated location data repositories in California," said Jennifer Lynch, EFF's General Counsel, at a press conference announcing the filing. "Every time you drive in San Jose, your movements are potentially being logged and could be searched by any officer for any reason."

San Jose's ALPR network, operated in partnership with Flock Safety, captures approximately 1.2 million plate reads per day across the city's camera infrastructure. Unlike cell phone location data, which the Supreme Court in 2018 ruled requires a warrant, ALPR data collected on public roads has occupied a legal gray area.

The lawsuit argues that the aggregation of plate reads over time creates a comprehensive record of individuals' lives -- where they worship, seek medical care, attend political meetings, and visit -- and that this aggregate profile triggers Fourth Amendment warrant protections under the Supreme Court's reasoning in Carpenter v. United States.

San Jose officials defended the practice, arguing that individuals have no reasonable expectation of privacy in the location of their vehicles on public streets. The city's legal team noted that ALPR data has been instrumental in solving hundreds of crimes including homicides and kidnappings.

Civil liberties groups acknowledged the public safety value but argued that a warrant requirement would not meaningfully impair legitimate investigations while protecting residents from dragnet surveillance. A preliminary injunction hearing is scheduled for spring 2026.