SIREN, et al. v. City of San Jose, et al.

The ACLU of Northern California and the Electronic Frontier Foundation filed suit in Santa Clara County Superior Court against the City of San Jose and others to challenge San Jose police officers’ practice of searching for location information collected by automated license plate readers (ALPRs) without first getting a warrant.

The San Jose Police Department has blanketed the city’s roadways with nearly five hundred Automatic License Plate Readers (ALPRs). The police department uses this unblinking surveillance network to indiscriminately collect millions of records per month about people’s movements, and keeps this ALPR data for an entire year. Then the police department allows its officers, and other law enforcement officials from across the state, to search this ALPR database to instantly reconstruct people’s locations over time — without first getting a warrant. This is an unchecked police power to scrutinize the movements of San Jose’s residents and visitors as they lawfully travel to work, to the doctor, or to a protest.

San Jose’s ALPR surveillance program is especially pervasive in both time and place. Few California law enforcement agencies retain ALPR data for an entire year, and few have deployed nearly five hundred cameras. Moreover, most residents of San Jose need to drive in order to commute, shop, or pick of their kids.

In November 2025, the ACLU of Northern California and the Electronic Frontier Foundation filed suit in California state court. We represent non-profit organizations that serve San Jose residents and that must travel throughout the city to do so: SIREN and CAIR California. We’ve sued the City of San Jose and its police chief and mayor. We challenge their practice of allowing police officers, without a warrant, to search San Jose’s massive trove of ALPR data. We allege that this practice violates the California Constitution’s ban on unreasonable searches and its guaranty of privacy. We ask the court to declare that these warrantless searches are unconstitutional, and to order defendants to end this practice.