The **Marin County Sheriff’s Office (MCSO)** has once again drawn the ire of privacy advocates for its handling of automated license plate reader (**ALPR**) data. The **EFF** and the **ACLU of Northern California** have issued a demand letter and a public records request, accusing **MCSO** of illegally sharing **ALPR** information with federal and out-of-state agencies. This alleged breach of protocol follows a report by the *Point Reyes Light* detailing how **MCSO** provided non-California agencies with access to its **ALPR** database. Such actions directly violate California law, specifically **SB 34**, which prohibits sharing **ALPR** data with out-of-state or federal entities for any reason. Furthermore, if shared for immigration enforcement purposes, it also contravenes **SB 54**. **ALPRs** are a mass surveillance technology, deploying cameras to capture vehicle images and upload their location data to searchable, shareable databases. This indiscriminate collection raises significant privacy concerns for every driver. Network audit logs obtained by the *Point Reyes Light* reveal a disturbing pattern: during the final months of 2024, **MCSO** shared **ALPR** data with numerous out-of-state and federal agencies. Notably, there were 254,131 instances of such data sharing in November 2024 alone. Many of these searches originated from law enforcement in states with restrictive reproductive care laws and a history of assisting **ICE**, including Alabama, Indiana, Kentucky, Florida, and Texas. Advocates argue this sharing exposes sensitive driver location information to potential misuse by the federal government and states lacking California's robust privacy protections. ### A History of Non-Compliance This is not the first time **MCSO** has been accused of unlawfully sharing **ALPR** data. In 2021, the **EFF** and **ACLU** sued the Marin County Sheriff for illegally sharing millions of local drivers' license plate numbers and location data with hundreds of federal and out-of-state agencies, including **ICE** and **Border Patrol**. The lawsuit, *Lagleva v. Marin County Sheriff*, resulted in a settlement agreement. Under the terms of this agreement, the Sheriff consented to cease sharing license plate and location information with agencies outside of California, thereby complying with **SB 34** and **SB 54**. “**MCSO**’s November 2024 audit report shows that your office has violated not only **SB 34**, but the terms of the *Lagleva* Settlement Agreement as well,” the demand letter states. ### Calls for Audit and Accountability The **EFF** and **ACLU** are now urging **MCSO** to conduct a comprehensive audit of its **ALPR** database, implement new compliance protocols, and impose penalties on any employee found to be sharing **ALPR** information out-of-state. “While your office claims that it took deliberate steps to disable nationwide data-access capabilities and ensure your system operated within strict privacy safeguards, you have not explained how outside agencies nonetheless obtained access, how you plan to prevent future violations of **SB 34** and the *Lagleva* Settlement Agreement, or why you did not take steps to inform the public and the Marin County Inspector General once you learned about the breach,” the letter further elaborates. This incident underscores a recurring issue where many California agencies appear to disregard state laws, exposing sensitive location information and putting communities at risk. With federal agencies continuing **ICE** raids and several states enforcing severe restrictions on abortion, **ALPR** technology is increasingly used to target and surveil immigrants and abortion seekers. Advocates maintain that **ALPR** programs are incompatible with protecting residents' rights, and California agencies, including **MCSO**, have a fundamental obligation to safeguard the rights of Californians, even when not recognized by other states or the federal government. The full demand letter can be accessed [here](https://www.eff.org/document/20261001-letter-aclu-norcal-and-eff-marin-sheriff).