They're mounted on poles along roadways across St. Lucie County and thousands of other communities nationwide: camera systems made by the company Flock Safety that photograph passing license plates, log the time and location, and check the plate against law enforcement watch lists.
Supporters say the cameras are a straightforward crime-fighting tool. Critics say they amount to a mass surveillance network — and the debate is playing out in Florida as much as anywhere else.
Flock's cameras now number around 120,000 across 49 states, and the data they collect is shared among thousands of law enforcement agencies, according to St. Lucie County Sheriff Richard Del Toro.
"There's a lot of concerns about the fact that... those cameras are available to basically thousands of law enforcement agencies across the country where we share information," Del Toro said. He said critics worry that agencies are tracking residents' movements, that interagency data-sharing lacks sufficient justification, and — most seriously — that individual officers could misuse the system.
Jay Stanley, senior policy analyst with the American Civil Liberties Union's Speech, Privacy, and Technology Project, goes further, describing Flock's network as a system built to watch everyone, not just people suspected of a crime.
"Flock has taken license plate scanning places that it's never been in its short history by selling thousands and thousands of cameras around the country and centralizing them using cloud services," Stanley said. "In essence, [it's] creating a giant mass surveillance system that extends across the whole country. And mass surveillance is something that I think Americans don't want."
Stanley, who has studied license plate readers for about 15 years, said the data can reveal far more than where a car has been. "That can be very sensitive information. It can reveal things about your political life, your religious life, your sexual life, what doctor's offices you visited, much more," he said.
Stanley said opposition to Flock's cameras isn't confined to one side of the political spectrum. "We're seeing opposition from leftists. We're seeing opposition from MAGA Republicans, from mainstream Republicans, from centrists," he said. "I wouldn't count anybody out, no matter how conservative, liberal or in the middle they are, because Americans really don't like this... system."
His organization's position: communities shouldn't adopt license plate readers at all. Where they already exist, the ACLU recommends strict limits — including short data retention windows, a ban on sharing data outside the local agency, and oversight of who ends up on watch lists.
Stanley pointed to New Hampshire, which he said limits retention of data on plates with no hits to just three minutes, preventing the system from functioning as a long-term surveillance tool. He also raised concerns about errors on police watch lists and the use of artificial intelligence to flag "suspicious" driving patterns.
"Maybe the car you rented got stolen two weeks ago and they didn't update it," he said. "The police pull you over thinking that you are a car thief, and they are pointing guns at you. And this happens to people."
Del Toro said he doesn't dispute that the cameras work. Automated license plate readers have helped identify stolen vehicles, locate wanted people, and generate investigative leads, he said. The real issue, in his view, is oversight.
"I think the bigger issue is governance of these systems," Del Toro said. "Who may search the system for what purpose, how the searches are documented, who can locally see the collected information, how long we retain it for."
He said he has directed a captain in his office to conduct a full review and audit of the agency's Flock usage, and acknowledged that safeguards across the industry have been thin. "I can basically use the system and run a license plate... but if I'm doing it for personal reasons, say I'm trying to track my ex-spouse... that could be dangerous," he said.
He noted that Flock itself has shortened its data retention window from 30 days to seven, and said his agency now requires deputies to tie any plate search to a specific case number. "I can show exactly why I ran the plate," he said. "It's part of an investigation. It's documented. I'm not just out here randomly searching things."
Del Toro said the cameras have helped track down a homicide suspect, locate other wanted suspects, and find missing people, including those with Alzheimer's or dementia who wandered off in a vehicle. He argued that drivers on public roads have no reasonable expectation of privacy, noting that smartphones and social media already collect far more personal data than a license plate camera does.
"This is simply a license plate reader that gives us the information about what vehicle traveled through a certain area at a certain time and date," he said.
Both men agreed that public trust — and the rules governing the technology — will shape what comes next. Del Toro said he understands why some residents are wary, pointing to a broader erosion of trust in government and law enforcement in recent years.
"Trust... takes years to build, seconds to lose," he said. "This is just another tool. It's going to help us if we use it the right way to solve crimes. If there's no crime going on, there's really no reason to even look at the data."
Stanley said the outcome should be decided democratically, community by community. "It should be worked out through the democratic political system," he said.