Every month, roughly 20 billion license plates are scanned by Flock Safety’s automated license plate reader network, a figure the company says reflects the growing role of camera technology in modern policing. Across the U.S., law enforcement agencies increasingly rely on automated license plate readers (ALPRs) to develop investigative leads and connect crimes that might otherwise remain unsolved.

But as the technology spreads, so has a national debate over its reach. Civil liberties organizations, privacy advocates and some local governments argue that the same systems helping investigators solve crimes are also creating an unprecedented form of mass surveillance that records the daily movements of millions of law-abiding Americans.

Flock Safety has emerged as one of the country’s largest providers of ALPR technology, with an estimated 80,000 to 100,000 cameras installed in cities and rural communities, according to the American Civil Liberties Union (ACLU). The cameras are mounted along highways, neighborhood entrances, commercial corridors and other locations where vehicles regularly pass.

Unlike traditional traffic cameras, which typically capture images only when a driver commits a violation, ALPR cameras continuously scan passing vehicles. AI identifies characteristics including a vehicle’s make, model, color and license plate while also noting distinguishing features such as bumper stickers, roof racks, dents or other visible damage.

Law enforcement agencies say that information has become an invaluable investigative resource.

Flock says its AI-powered platform allows investigators to search for vehicles even when a complete license plate is unavailable. Officers can search using descriptive characteristics rather than exact plate numbers, potentially generating leads from witness accounts that otherwise would produce little investigative value.

The company says every search is logged, tied to a specific user and subject to agency oversight. Access is controlled by each law enforcement agency, which determines who may use the system and whether to share information with other agencies. Flock also emphasizes that its cameras do not use facial recognition technology and cannot identify or track individuals, only vehicles.

According to Flock’s inaugural 2025 Impact Census, based on survey responses from nearly 700 law enforcement agencies across 43 states, the technology supported approximately 1 million investigations during the year. The company estimates that Flock-assisted investigations contributed to about 20% of cleared cases in jurisdictions using the technology, helped locate approximately 10,000 missing people and played a significant role in recovering stolen vehicles.

Supporters argue those numbers validate why ALPR systems are so important. Law enforcement agencies have credited the technology with helping identify suspects in homicides, robberies, kidnappings and vehicle thefts while providing investigators with leads that might otherwise have taken weeks to develop or never have emerged.

The technology also enables agencies to collaborate across jurisdictions. A vehicle connected to a crime in one city may later be identified hundreds of miles away, allowing investigators to share information more quickly than through traditional investigative methods.

But critics argue those same capabilities create sweeping surveillance that go beyond criminal investigations.

The ACLU contends that companies such as Flock are building a nationwide surveillance network capable of tracking the movements of millions of people who are not suspected of any crime. The organization says only about 1% of vehicles scanned by ALPR systems are connected to criminal activity, meaning the overwhelming majority of collected data involves law-abiding motorists.

The ACLU argues that the technology effectively creates detailed travel histories capable of revealing sensitive personal information, including visits to physicians, places of worship, political meetings, protests or private residences.

“It doesn’t matter which company has its cameras in your neighborhood,” the ACLU argues. “They all have the same problems: a lack of transparency, oversight and regulation into how they collect, store and use our data.”

Privacy advocates have also raised concerns about how long agencies retain collected information and how broadly it can be shared among law enforcement agencies.

Flock says participation in broader data-sharing networks is voluntary and controlled by each customer agency rather than the company itself. Agencies decide whether to share information with other jurisdictions, and those decisions are governed by local agreements and policies.

The ACLU says that those safeguards are inadequate, without stronger legal protections. The organization points to several instances in which ALPR technology has allegedly been misused by law enforcement officials.

“The fundamental problem with these systems is that they place private information about people’s movements over time in the hands of every officer,” said Michael Soyfer, an Institute for Justice attorney who is representing residents of San Jose and Norfolk in lawsuits challenging their cities’ ALPR surveillance networks. “Without the constitutional safeguard of a warrant requirement, that predictably allows officers to abuse their access to these systems for things like stalking romantic partners.”

There have been several cases in which law enforcement officials are alleged to have used ALPR technology outside of the parameters of their role as police. An officer with the Milwaukee Police Department recently resigned after he was suspended from that department for using the technology to allegedly search the license plates of two individuals, one of them he had been in a previous relationship with.

The ACLU also says there have been incidents involving mistaken identifications. In one Colorado case, officers allegedly detained a family at gunpoint after an ALPR system incorrectly identified their vehicle as stolen. In another case, a 12-year-old girl in New Mexico was handcuffed after an ALPR camera reportedly misread the license plate of the vehicle she was riding in.

Flock has consistently argued that accountability depends on agency policies and oversight rather than the technology itself. The company says every search is permanently logged, supervisors can audit user activity, and agencies retain control over who may access information and under what circumstances.

According to the ACLU, more than 55 local governments have ended contracts with Flock during the past year amid public opposition. Other jurisdictions have adopted ordinances limiting how long license plate data may be retained or restricting when officers may access the system.

The ACLU has spent more than a decade advocating for stronger oversight of ALPR systems. In 2026, the organization released model legislation establishing limits on data retention, access and sharing while continuing litigation challenging the constitutionality of large-scale license plate surveillance under the Fourth Amendment.

Meanwhile, Flock argues that clear governance, transparency and auditability can address privacy concerns without sacrificing investigative effectiveness.

As camera technology becomes more sophisticated and AI expands its capabilities, communities will likely continue weighing those competing priorities. For law enforcement agencies, ALPR systems represent an increasingly powerful investigative resource. For privacy advocates, they raise enduring questions about surveillance, constitutional protections and the limits of government monitoring in everyday life.