ALPR: How Automated License Plate Readers Track You

• What is ALPR (automated license plate readers)?
• How do license plate readers work?
• Why ALPR license plate surveillance matters
• Real-world examples: errors, leaks, and controversial searches
• Is ALPR legal? The current legal landscape
• What you can do about ALPR license plate tracking
• FAQ: ALPR, Flock Safety, and digital license plates

ALPR (also called an ALPR camera or automated license plate reader) is a camera system that photographs passing vehicles and turns the plate into searchable text—making license plate tracking possible at scale. In practice, automated license plate readers can create a location history for ordinary drivers because non-matching reads are often stored, not discarded.

What is ALPR (automated license plate readers)?

Automated License Plate Readers (ALPRs) are camera systems designed to capture images of vehicles and extract license plate numbers using optical character recognition (OCR). Each “read” typically includes the plate number, the date and time, and a GPS location—and often extra details about the vehicle itself, like make, color, and visible identifiers (bumper stickers, damage), sometimes described as a vehicle “fingerprint.”

ALPRs are often presented as a way to spot specific vehicles quickly. They do that by comparing plate reads against hotlists (for example, stolen vehicles, wanted persons, or Amber Alerts). But a key privacy issue is that non-matching vehicles can still be stored—which means the system can build a database of where many people drove, even if they were never suspected of a crime.

ALPRs show up in two common formats:

• Fixed ALPR cameras (mounted on poles, buildings, or signs)
• Mobile ALPR cameras (mounted on patrol cars)

In many deployments, the data is stored in a vendor cloud rather than on city-owned servers. In the case of Flock Safety, reporting and documentation cited in the research context describe a standard 30-day retention period for scans.

ALPR vs. digital license plate: not the same thing

It’s easy to mix up ALPR with a digital license plate. They’re related only in the sense that both can affect tracking.

• ALPR: a camera system watching the road and reading plates from the outside.
• Digital license plate: a physical electronic plate that replaces the traditional metal plate.

One widely discussed example of a digital license plate is Reviver’s RPlate, an electronic display plate that was legalized in California in 2023. The research context notes that in January 2023, researchers gained “super administrative” access to Reviver’s systems, with the ability to track every RPlate’s GPS location and falsely tag vehicles as stolen; Reviver said it patched the flaw in 24 hours.

How do license plate readers work?

At a high level, ALPR systems follow a predictable pipeline: capture → extract → check → store → search/share.

1. Capture an image: An ALPR camera photographs the back (or sometimes front) of a vehicle as it passes.
2. Convert image to text (OCR): Software reads the characters on the plate and converts them into searchable text.
3. Attach metadata: The system records details such as date/time and GPS location, and often vehicle descriptors (make, color, visible markings).
4. Compare to hotlists: The plate read is checked against lists like stolen vehicles or Amber Alerts. Matches can alert officers.
5. Store non-matches: The major privacy shift is here—non-matching reads can still be kept, turning “spot checks” into a searchable history.
6. Search and share: Authorized users can search by plate number, location area, date/time range, and other filters. With sharing enabled, searches can expand beyond a single city or county.

How accurate are ALPR cameras?

Accuracy depends on lighting, speed, camera angle, and the quality of the OCR. The research context cites an EFF-referenced study finding ALPRs misread the state of roughly 1-in-10 plates. Even small errors matter when the system is used to justify stops, detentions, or gunpoint encounters.

How big is the Flock Safety license plate surveillance network?

In the U.S., one of the most prominent vendors is Flock Safety. The research context reports that as of 2025, Flock is valued around $7.5 billion and operates in over 5,000 communities across 49 states, with roughly 100,000 cameras and over 20 billion vehicle scans per month.

Scale changes what “license plate tracking” means. With sharing enabled, the context notes that a single local search can sweep thousands of networks and tens of thousands of cameras nationwide—so an officer in one jurisdiction can effectively look far beyond their own streets.

ALPR data doesn’t only come from police cameras

ALPR databases can also be built from commercial sources. The research context notes that Motorola Solutions owns Vigilant Solutions (acquired in 2019), described as running the largest commercial ALPR database, with 5+ billion records as of 2019 and growth of 150–200 million scans per month from repossession, towing, and parking sources. The context also notes Axon sells ALPR cameras.

Why ALPR license plate surveillance matters

If ALPR only alerted on truly rare hotlist hits and discarded everything else, the stakes would be lower. The stakes rise because ALPR systems can enable persistent, retroactive tracking of ordinary people—sometimes with minimal accountability.

ALPR license plate tracking isn’t limited to suspects

The research context emphasizes that non-matching reads are still stored, building a location history for “every passing car,” not just people suspected of a crime. That means the database can reveal patterns—where you sleep, work, worship, get medical care, or spend time with family—simply because you drove past a camera.

This is especially sensitive when it can expose visits to:

• Clinics (including reproductive healthcare)
• Places of worship
• Protests
• Gun shows

If you’ve been following facial recognition debates, ALPR is a close cousin: it tracks the vehicle as a stand-in for the person. For a broader look at biometric tracking, see facial recognition and the ethical issues in facial recognition ethics. And if you’re trying to understand how tracking can expand from cars to identity systems, see digital ID.

Cross-state sharing can override local privacy expectations

The research context warns that cross-state sharing means data collected in a privacy-protective state can be queried by agencies in states pursuing different priorities—such as abortion criminalization or immigration enforcement. In other words, “I live in a state with stronger privacy norms” may not protect you if the network is interconnected.

Public records can become a leak

Even when agencies claim controls are in place, data can spill through routine processes. The research context cites the HaveIBeenFlocked project, which exposed roughly 2.3 million license plates after departments failed to redact public-records logs.

Real-world examples: errors, leaks, and controversial searches

It’s hard to judge a surveillance tool just by its brochure. The most useful reality check is documented errors, documented misuse, and documented court fights.

Wrongful stops tied to ALPR errors

When ALPR systems are wrong, the consequences can be immediate and frightening—especially when an alert is treated as proof instead of a lead.

• Brittney Gilliam (Aurora, Colorado, 2020): A family—including children—was held at gunpoint after a Colorado SUV was mistakenly associated with a stolen Montana motorcycle plate. The city settled for $1.9 million.
• Denise Green (San Francisco, 2009): An ALPR misread a “3” as a “7.” She was held at gunpoint; the case settled for $495,000.
• Isoke Robinson (Detroit): A misidentified Dodge Charger led to her 2-year-old being handcuffed, and her car was impounded for three weeks.

These cases underline a basic point: an automated match is not the same thing as reliable evidence, especially when the system can misread plate details and even the plate’s state.

ICE and CBP access controversies (Flock searches)

The research context includes several documented surveillance controversies tied to Flock Safety searches and access:

• May 2025: 404 Media reported that local police ran Flock searches on behalf of ICE despite ICE having no Flock contract. This was reportedly identified because officers typed “ICE” or “illegal immigration” into the search-reason field; the reporting cited 4,000+ such lookups.
• August 2025: Customs and Border Protection (CBP) accessed Flock data from agencies that never agreed to share federally; Flock described it as a “pilot program.”

Even if you support some enforcement goals, these examples raise a governance question: who gets access, and who actually consented to that access?

A documented abortion-related search across 83,345 cameras

In a widely cited example of how “one search” can become mass tracking, the research context notes that in May 2025, a Texas sheriff in Johnson County used Flock’s nationwide network to search for a woman who had a self-managed abortion, with the search reason logged as “had an abortion.” The context states that one search swept 6,809 networks and 83,345 cameras across a month, including in states where abortion is legal.

This is the practical meaning of license plate surveillance at national scale: a local investigation can reach far beyond local roads.

Protest-related searches and vague justifications

The research context cites an EFF analysis of ~12 million Flock searches by 3,900+ agencies over 10 months (Dec 2024–Oct 2025). In that dataset, 50+ agencies ran protest-related searches, and about 20% of searches had only vague reasons like “investigation.”

If search reasons are vague, auditing becomes harder: the public (and even oversight bodies) may struggle to distinguish legitimate investigations from fishing expeditions.

Cameras exposed on the open internet

ALPR privacy risk isn’t only about government use; it’s also about security. The research context notes that 404 Media found at least 60 Flock “Condor” cameras streaming live on the open internet without authentication. It also notes that in November 2025, lawmakers urged the FTC to investigate Flock over weak login security.

Is ALPR legal? The current legal landscape

In the U.S., ALPR legality is a patchwork: constitutional arguments, state laws, and local policies all matter. One reason the debate is so intense is that ALPR changes the scale of tracking—turning scattered observations into searchable history.

A key court fight: Norfolk, Virginia (Institute for Justice)

The research context describes a major lawsuit filed by the Institute for Justice (IJ) against Norfolk, Virginia in October 2024, challenging the city’s network of 176 Flock cameras. IJ argued that warrantless mass tracking violates the Fourth Amendment, relying on the logic of Carpenter v. United States (a U.S. Supreme Court case about long-term location tracking via cell-site location data).

Key procedural milestones in the research context:

• February 2025: The court denied Norfolk’s motion to dismiss.
• January 2026: Judge Mark Davis ruled the warrantless use constitutional and dismissed the case, reasoning the data did not capture movements “in their entirety.” IJ said it would appeal.

Case details and updates are available from IJ: Norfolk, Virginia camera surveillance case page.

Are ALPR images public records?

The research context notes that a judge ruled Flock surveillance images are public records anyone can request. That can cut both ways: public-records access can help communities audit surveillance, but it can also create new exposure risks if sensitive information is released or poorly redacted.

The same context also notes that two members of Congress opened a formal investigation into Flock in 2025.

A concrete state limit: Washington SB 6002 (effective March 30, 2026)

Some jurisdictions are writing rules specifically for ALPR. The research context highlights Washington’s SB 6002, which becomes effective March 30, 2026 and bars ALPR collection near:

• Schools
• Courts
• Food banks
• Places of worship
• Immigration facilities
• Reproductive-healthcare sites

This kind of rule matters because it’s targeted: it’s about keeping license plate surveillance away from highly sensitive locations where people may have constitutional or safety reasons to avoid being tracked.

Can you block an ALPR camera with a plate cover or spray?

The research context warns about a practical reality: plate covers and obscuring sprays are illegal in many states and modern ALPR systems defeat many of them. One named example in the context is Florida HB 253, effective July 1, 2024.

What you can do about ALPR license plate tracking

You usually can’t opt out of driving past an ALPR camera. But you can influence where cameras are placed, how long data is kept, who it’s shared with, and what oversight exists. The research context includes several concrete steps and tools.

1) Ask: is your town using ALPR (or Flock Safety)?

Start by figuring out whether ALPR is already deployed where you live, work, or take your kids to school.

• DeFlock.me maps ALPR camera locations; the context notes it has mapped 16,000+ locations.
• The EFF Atlas of Surveillance identifies 1,700+ agencies using ALPRs (per the research context).

Once you know the vendor and the footprint, you can ask better questions at city council, school board, or county commission meetings.

2) Learn from places that said “no”

The research context notes that in 2025, nearly two dozen communities rejected or ended Flock programs, including:

• Austin, Texas (ended June 2025)
• Cambridge, Massachusetts (terminated December 2025)
• Eugene/Springfield, Oregon

You don’t have to reinvent the wheel: communities often debate the same issues—sharing, retention, audit logs, and whether cameras end up monitoring sensitive locations.

3) Push for specific rules (not vague promises)

If your city is considering ALPR, the most protective policies are specific and auditable. Based on the harms and controversies in the research context, here are concrete questions to insist on answers for:

• Retention: What’s the default retention (for example, Flock’s standard 30 days), and can it be shortened?
• Sharing: Is sharing enabled? With whom (neighboring towns, statewide, nationwide)? Can it be turned off?
• Search reasons: Are search reasons required and specific (not “investigation”)?
• Auditing: Are audit logs kept, reviewed, and published (at least in aggregate)?
• Sensitive locations: Are cameras barred near clinics, schools, houses of worship, and protest-prone civic areas (as Washington SB 6002 does)?

If you’re looking for broader strategies beyond ALPR, see /fighting-back/ for practical ways ordinary people are pushing back against surveillance.

4) Use public-records requests to get the truth

The research context specifically recommends filing public-records requests for:

• ALPR audit logs (who searched, when, and why)
• Sharing settings and sharing agreements

This matters because many controversies were revealed through logs—like officers writing “ICE” or “illegal immigration” as reasons for searches in the 404 Media reporting, or vague “investigation” reasons in the EFF analysis.

If you want more examples of documented surveillance harms and legal disputes, browse /ai-incidents/ and /ai-lawsuits/.

ALPR vs. “digital license plate”: a quick comparison

People often worry about digital license plates because they sound like built-in tracking. But ALPR is already a form of tracking—without any special plate at all.

• What ALPR needs: cameras + software that reads plates + a database.
• What a digital license plate changes: the plate itself becomes an electronic system that can introduce additional security and privacy risks if hacked or mismanaged (as shown by the January 2023 Reviver “super administrative” access incident in the research context).

Comparison points:

• ALPR: Tracks vehicles by capturing them on the road; non-matches can be stored; can be searched across large networks; accuracy issues (including misreading the state about 1-in-10 times per the EFF-cited study).
• Digital license plate (Reviver RPlate): Physical electronic plate legalized in California in 2023; a January 2023 security incident enabled GPS tracking of every RPlate and false “stolen” tags (patched in 24 hours, per Reviver).

FAQ: ALPR, Flock Safety, and digital license plates

Do automated license plate readers record everyone?

ALPR systems check plates against hotlists, but the research context states that non-matching reads are still stored in many deployments. That means the system can create a searchable record of where many ordinary vehicles were seen.

How long does Flock Safety keep license plate data?

The research context states that Flock’s standard retention is 30 days. Policies can vary by agency, but “standard” matters because it’s often the default unless a community negotiates or mandates something different.

Can one agency search cameras in other states?

Yes, if sharing is enabled. The research context says that with sharing turned on, a single local search can sweep thousands of networks and tens of thousands of cameras nationwide. It also gives a concrete example: a May 2025 search that swept 6,809 networks and 83,345 cameras.

Are ALPR cameras accurate enough to justify a traffic stop?

ALPR matches can be useful leads, but they can be wrong. The research context cites an EFF-referenced study finding ALPRs misread the state of roughly 1-in-10 plates, and it lists multiple wrongful-stop cases where people were held at gunpoint (including settlements for Brittney Gilliam and Denise Green).

Is there any law limiting where ALPR cameras can be used?

Yes in some places. The research context highlights Washington’s SB 6002 (effective March 30, 2026), which bars ALPR collection near sensitive locations including schools, courts, places of worship, immigration facilities, and reproductive-healthcare sites.

What’s the best first step if I’m worried about license plate surveillance?

Use mapping and transparency tools to learn what’s already deployed (the research context cites DeFlock.me and the EFF Atlas of Surveillance), then ask your local government for policies, audit logs, and sharing settings. If you want a broader playbook for civic action, see /fighting-back/.

Conclusion: ALPR cameras make license plate tracking easy—so rules matter

ALPR systems—whether you call them an ALPR camera network or automated license plate readers—are powerful because they turn everyday driving into searchable data. The research context shows the stakes in concrete numbers (Flock’s scale in 2025), concrete controversies (ICE/CBP access issues and abortion-related searches), and concrete harms (wrongful stops and public-records leaks).

If you want to keep up with how these systems impact real people—and what communities are doing about it—use Ban the Bots resources: learn about documented harms at /ai-incidents/, track court fights at /ai-lawsuits/, and find practical ways to respond at /fighting-back/. For the bigger picture on tech-driven disruption and backlash, see /ai-backlash/—and if you’re tracking how automation affects livelihoods too, start at /ai-layoffs/. You can also explore where infrastructure shows up in your region via /data-center-map/.