Short answer: beyond your local police, subscriber agencies can share plate data, and there are documented examples of out-of-state agencies accessing other states' readers. Exactly who can query the network is rarely disclosed.
Local police and subscribers
Flock sells access to law enforcement and, in some cases, other groups. Each subscriber agency can query plate data for the cameras it operates — and increasingly, data is pooled across the network.
Cross-state sharing
In California, out-of-state police accessed Silicon Valley plate readers, reigniting the privacy debate. That single story illustrates how access can extend far beyond the agency that installed the camera.
The transparency problem
Most agencies don't publish who can access their plate data, how often it's queried, or what the data is used for. That's why FOIA requests and local reporting matter: they're often the only way the public learns what's happening.
What advocates want
- Public access logs for every agency.
- Limits on cross-state and third-party access.
- Rules against using plate data for personal ends (the stalking risk).
- Retention limits (how long data is kept).
See the state legality board for what's reported in your state, and the ban tracker for jurisdictions pushing back.