Tell the City: ALPRs and Flock Out of San Mateo, CA
The Issue
This petition is adapted from a constituent letter sent to the San Mateo mayor, deputy mayor, and council members on August 10, 2026.
As members of the San Mateo community, we the undersigned emphatically oppose the City's use of Automated License Plate Readers (ALPRs) and other dragnet surveillance devices. The City's position that it values the privacy of its residents cannot reconciled with its continuing use of ALPRs in their current configuration, and the use of these devices poses serious threats to our rights to due process under the 4th Amendment to the Constitution.
We demand that the City immediately turn off and uninstall ALPRs and terminate any contracts with Flock Safety or allow them to expire.
The City alternatively has the power to enact measures to mitigate the privacy violations and potential for abuse inherent to the use of such systems by 1) imposing stricter limits on the data retention period, 2) clarifying the San Mateo Police Department ALPR Policy language, and 3) requiring that audits of the system and data searches be independent and public.
BACKGROUND
ALPRs are being used to perform broad surveillance, harassment, and violate the law
Flock Safety ALPRs enable government contractees to conduct mass, indiscriminate surveillance that extends far beyond the scope of a traditional license plate reader. The cameras do not merely record license plates, they also capture vehicle attributes—including make, model, color, and personalized effects such as decals and bumper stickers—along with pedestrians and cyclists (1). This enables anyone with access to the system to target specific individuals and search by personal effects or physical characteristics, and indeed, police officers across the country have been repeatedly exposed as using Flock Safety to do just that (1,2). These searches rely on Flock Safety’s AI and facial recognition system (a technology that is inherently racist and frequently unreliable).
In just the last 2 years, Flock Safety has violated agreements with multiple California contractees and California law by accessing data without the local police department’s permission or knowledge (3) and by sharing data with out-of-state law enforcement agencies (4,5). Continuing to trust Flock Safety with our personal data after these surreptitious and negligent data breaches constitutes a betrayal of the community’s trust in the City, despite Police Department audits of the system (discussed below).
These violations only scratch the surface, with more and more evidence of Flock Safety's and other surveillance companies' wrongdoing being revealed with regularity.
Data retention policy enables perpetual surveillance
The City website states that the ALPR system “does not retain private vehicle registrant information of any kind.” This statement is misleading considering that location data is among the most private of personal information, and appears to have been crafted to offer residents a false assurance of privacy protection. The Flock Safety Transparency Portal states that data—which includes time and location—is retained, and for 30 days after collection. Whether or not an individual’s “private vehicle registrant information” as defined by the City is stored in the ALPR system, the data is necessarily connected to a specific vehicle and thus allows identification of its registered owner as the vehicle operator at the time of data capture and at a specific location.
The prolonged data retention period means people are susceptible to potential implication in criminal activity for every 30-day period after which they pass in front of an ALPR. In practical terms, this means people in our community are surveilled in perpetuity, in that traveling in a manner that avoids government surveillance devices is impractical or impossible.
The San Mateo Police Department ALPR Policy states that data “downloaded to the server should be stored for 30 days from the collection date,” (emphasis ours) and does not clearly indicate that data unconnected to a criminal investigation will be deleted 30 days after collection. Regardless of Flock Safety’s claim that data is automatically deleted by the specified time frame, the Policy’s permissive language opens a loophole whereby data unconnected to a criminal investigation could be retained for longer than 30 days because the Policy does not explicitly prohibit retention beyond the 30-day period.
Mitigating the impact on individual privacy and due process
While we strongly prefer that the City completely dismantle ALPRs and other surveillance devices and terminate any contract with Flock Safety, the City has the power to implement and enforce measures to better protect the privacy and due process of residents and others coming into our city while still reasonably satisfying law enforcement objectives, as follows:
[Note: after composition of this letter, the San Mateo Civil Grand Jury released a report identifying several deficiencies with how San Mateo, among other Bay Area jurisdictions, handles ALPR data (6); these alternative demands are complementary and additive to the jury's recommendations.]
- Impose stricter limits on the data retention period. Other government bodies have successfully balanced the aims of law enforcement with community privacy. For example, New Hampshire law requires that license plate reader data be purged and made irrecoverable within 3 minutes after collection, unless a scan registers an alarm under proscribed conditions (eg, vehicle reported as stolen, missing persons, etc). Additionally, the New Hampshire law prohibits the use of license plate readers to capture anything beyond what is necessary to check license plates, and prohibits photographs or video capture of people.
- Clarify policy language. The San Mateo Police Department ALPR Policy language should unambiguously define the requirements for deletion of ALPR data. Flock Safety’s assurances that data is deleted after a period of 30 days is irrelevant when the contractee is the party that determines how long data is retained.
- Conduct regular independent and public audits of the ALPR system. The San Mateo Police Department ALPR Policy states that regular audits of data searches and the ALPR system will be conducted, but the Policy contains no provision that the auditor shall be independent of those who benefit from use of the system. An internal audit is of no value if this independence cannot be assured. An appropriately detailed public report should be made available in a reasonable time frame after audit completion.
RE-ESTABLISHING TRUST WITH THE COMMUNITY
The Council might take note of the recent Supreme Court decision (Chatrie v. United States) that individuals have a reasonable expectation of privacy in records of their cell phone location, and that a geofence warrant is subject to 4th Amendment protections, no matter that the data is restricted to a narrow time frame and that a 3rd party hosts the data. One imagines a future in which indiscriminate collection of location data via the use of ALPRs and other surveillance devices will fall under this precedent; one also imagines a present where our government doesn’t casually exchange our liberties in pursuit of the perception of improved safety.
We hope the City will carefully consider our perspective and meet our demands.
---
References:
1. Cox Joseph, “How Cops Use Flock to Track People, Not Cars,” 404 Media, Jul 16 2026, https://www.404media.co/how-cops-use-flock-to-track-people-not-cars/
2. Harwell Drew et al, “How rogue officers turned a nationwide camera network into a tool for stalking,” The Washington Post, Aug 8 2026, https://www.washingtonpost.com/technology/2026/08/02/how-police-officers-used-vast-network-cameras-spy-their-exes/
3. Nielson Katie, “Mountain View ends its automated license plate reader contract with Flock Safety,” CBS News, updated Feb 24 2026, https://www.cbsnews.com/sanfrancisco/news/santa-clara-county-leaders-discussing-use-of-flock-cameras/
4. Rubin Ann, “Class action lawsuit alleges Flock license plate readers violate CA law and privacy of residents,” KTVU Fox 2, Feb 27 2026, https://www.ktvu.com/news/class-action-lawsuit-alleges-flock-license-plate-readers-violate-ca-law-privacy-residents
5. Kathan Jesse, “ICE accessed Capitola license plate data. Police say it was a mistake,” Santa Cruz Local, Nov 7 2025, https://santacruzlocal.org/2025/11/07/ice-accessed-capitola-license-plate-data-police-say-it-was-a-mistake/
6. Gokhale Tanay for Bay City News, "San Mateo County grand jury calls for stronger oversight for license plate readers; privacy watchdogs raise concerns over federal agencies’ access to ALPR data," The Almanac, Aug 6 2026, https://www.almanacnews.com/news/2026/08/06/san-mateo-county-grand-jury-calls-for-stronger-oversight-for-license-plate-readers/
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The Issue
This petition is adapted from a constituent letter sent to the San Mateo mayor, deputy mayor, and council members on August 10, 2026.
As members of the San Mateo community, we the undersigned emphatically oppose the City's use of Automated License Plate Readers (ALPRs) and other dragnet surveillance devices. The City's position that it values the privacy of its residents cannot reconciled with its continuing use of ALPRs in their current configuration, and the use of these devices poses serious threats to our rights to due process under the 4th Amendment to the Constitution.
We demand that the City immediately turn off and uninstall ALPRs and terminate any contracts with Flock Safety or allow them to expire.
The City alternatively has the power to enact measures to mitigate the privacy violations and potential for abuse inherent to the use of such systems by 1) imposing stricter limits on the data retention period, 2) clarifying the San Mateo Police Department ALPR Policy language, and 3) requiring that audits of the system and data searches be independent and public.
BACKGROUND
ALPRs are being used to perform broad surveillance, harassment, and violate the law
Flock Safety ALPRs enable government contractees to conduct mass, indiscriminate surveillance that extends far beyond the scope of a traditional license plate reader. The cameras do not merely record license plates, they also capture vehicle attributes—including make, model, color, and personalized effects such as decals and bumper stickers—along with pedestrians and cyclists (1). This enables anyone with access to the system to target specific individuals and search by personal effects or physical characteristics, and indeed, police officers across the country have been repeatedly exposed as using Flock Safety to do just that (1,2). These searches rely on Flock Safety’s AI and facial recognition system (a technology that is inherently racist and frequently unreliable).
In just the last 2 years, Flock Safety has violated agreements with multiple California contractees and California law by accessing data without the local police department’s permission or knowledge (3) and by sharing data with out-of-state law enforcement agencies (4,5). Continuing to trust Flock Safety with our personal data after these surreptitious and negligent data breaches constitutes a betrayal of the community’s trust in the City, despite Police Department audits of the system (discussed below).
These violations only scratch the surface, with more and more evidence of Flock Safety's and other surveillance companies' wrongdoing being revealed with regularity.
Data retention policy enables perpetual surveillance
The City website states that the ALPR system “does not retain private vehicle registrant information of any kind.” This statement is misleading considering that location data is among the most private of personal information, and appears to have been crafted to offer residents a false assurance of privacy protection. The Flock Safety Transparency Portal states that data—which includes time and location—is retained, and for 30 days after collection. Whether or not an individual’s “private vehicle registrant information” as defined by the City is stored in the ALPR system, the data is necessarily connected to a specific vehicle and thus allows identification of its registered owner as the vehicle operator at the time of data capture and at a specific location.
The prolonged data retention period means people are susceptible to potential implication in criminal activity for every 30-day period after which they pass in front of an ALPR. In practical terms, this means people in our community are surveilled in perpetuity, in that traveling in a manner that avoids government surveillance devices is impractical or impossible.
The San Mateo Police Department ALPR Policy states that data “downloaded to the server should be stored for 30 days from the collection date,” (emphasis ours) and does not clearly indicate that data unconnected to a criminal investigation will be deleted 30 days after collection. Regardless of Flock Safety’s claim that data is automatically deleted by the specified time frame, the Policy’s permissive language opens a loophole whereby data unconnected to a criminal investigation could be retained for longer than 30 days because the Policy does not explicitly prohibit retention beyond the 30-day period.
Mitigating the impact on individual privacy and due process
While we strongly prefer that the City completely dismantle ALPRs and other surveillance devices and terminate any contract with Flock Safety, the City has the power to implement and enforce measures to better protect the privacy and due process of residents and others coming into our city while still reasonably satisfying law enforcement objectives, as follows:
[Note: after composition of this letter, the San Mateo Civil Grand Jury released a report identifying several deficiencies with how San Mateo, among other Bay Area jurisdictions, handles ALPR data (6); these alternative demands are complementary and additive to the jury's recommendations.]
- Impose stricter limits on the data retention period. Other government bodies have successfully balanced the aims of law enforcement with community privacy. For example, New Hampshire law requires that license plate reader data be purged and made irrecoverable within 3 minutes after collection, unless a scan registers an alarm under proscribed conditions (eg, vehicle reported as stolen, missing persons, etc). Additionally, the New Hampshire law prohibits the use of license plate readers to capture anything beyond what is necessary to check license plates, and prohibits photographs or video capture of people.
- Clarify policy language. The San Mateo Police Department ALPR Policy language should unambiguously define the requirements for deletion of ALPR data. Flock Safety’s assurances that data is deleted after a period of 30 days is irrelevant when the contractee is the party that determines how long data is retained.
- Conduct regular independent and public audits of the ALPR system. The San Mateo Police Department ALPR Policy states that regular audits of data searches and the ALPR system will be conducted, but the Policy contains no provision that the auditor shall be independent of those who benefit from use of the system. An internal audit is of no value if this independence cannot be assured. An appropriately detailed public report should be made available in a reasonable time frame after audit completion.
RE-ESTABLISHING TRUST WITH THE COMMUNITY
The Council might take note of the recent Supreme Court decision (Chatrie v. United States) that individuals have a reasonable expectation of privacy in records of their cell phone location, and that a geofence warrant is subject to 4th Amendment protections, no matter that the data is restricted to a narrow time frame and that a 3rd party hosts the data. One imagines a future in which indiscriminate collection of location data via the use of ALPRs and other surveillance devices will fall under this precedent; one also imagines a present where our government doesn’t casually exchange our liberties in pursuit of the perception of improved safety.
We hope the City will carefully consider our perspective and meet our demands.
---
References:
1. Cox Joseph, “How Cops Use Flock to Track People, Not Cars,” 404 Media, Jul 16 2026, https://www.404media.co/how-cops-use-flock-to-track-people-not-cars/
2. Harwell Drew et al, “How rogue officers turned a nationwide camera network into a tool for stalking,” The Washington Post, Aug 8 2026, https://www.washingtonpost.com/technology/2026/08/02/how-police-officers-used-vast-network-cameras-spy-their-exes/
3. Nielson Katie, “Mountain View ends its automated license plate reader contract with Flock Safety,” CBS News, updated Feb 24 2026, https://www.cbsnews.com/sanfrancisco/news/santa-clara-county-leaders-discussing-use-of-flock-cameras/
4. Rubin Ann, “Class action lawsuit alleges Flock license plate readers violate CA law and privacy of residents,” KTVU Fox 2, Feb 27 2026, https://www.ktvu.com/news/class-action-lawsuit-alleges-flock-license-plate-readers-violate-ca-law-privacy-residents
5. Kathan Jesse, “ICE accessed Capitola license plate data. Police say it was a mistake,” Santa Cruz Local, Nov 7 2025, https://santacruzlocal.org/2025/11/07/ice-accessed-capitola-license-plate-data-police-say-it-was-a-mistake/
6. Gokhale Tanay for Bay City News, "San Mateo County grand jury calls for stronger oversight for license plate readers; privacy watchdogs raise concerns over federal agencies’ access to ALPR data," The Almanac, Aug 6 2026, https://www.almanacnews.com/news/2026/08/06/san-mateo-county-grand-jury-calls-for-stronger-oversight-for-license-plate-readers/
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Petition created on August 12, 2026