Denver’s Proposed ALPR Expansion Raises Legal and Civil Liberties Concerns
The City of Denver is considering a significant expansion of its automated license plate reader (ALPR) program, prompting renewed scrutiny from privacy advocates, civil liberties organizations, and members of the legal community. At issue is a proposed $666,000 amendment to the Denver Police Department’s (DPD) contract with surveillance technology vendor Flock Group Inc. The amendment would extend the current contract by two years and increase the total value of the agreement to over $1 million.
While city officials emphasize the program’s public safety benefits, critics warn that the proposal raises serious constitutional and policy concerns—particularly regarding mass surveillance, data retention, and federal agency access.
Understanding the ALPR System
Automated license plate readers are high-speed cameras that scan, time-stamp, and geolocate vehicle license plates. These data points are transmitted to a searchable database maintained by the DPD and used to identify vehicles associated with alerts or ongoing investigations.
Denver currently operates 111 ALPR cameras at 70 locations citywide. According to DPD officials, the technology has been instrumental in addressing a spike in vehicle thefts and has aided in the investigation of several major crimes, including homicides.
However, the same technology that enables real-time alerts for stolen vehicles also collects large volumes of location data from individuals who are not under suspicion—creating a broad surveillance apparatus with relatively little public oversight.
Legal Risks: Federal Access and Metadata Retention
One of the primary concerns relates to the potential for misuse or unauthorized sharing of ALPR data. While the DPD requires agencies requesting access to its data to attest that they will not share it with U.S. Immigration and Customs Enforcement (ICE), legal advocates argue that such agreements are insufficient.
Recent public records requests in Northern California revealed that ICE obtained access to massive amounts of location data collected by ALPR systems, despite local sanctuary policies. Once collected, data can be shared across multiple agencies and jurisdictions, often beyond the originating municipality’s control. The lack of enforceable, statutory restrictions heightens the risk of federal surveillance through local data collection tools.
Further, DPD reports that while license plate image data is deleted after 30 days, search logs—metadata reflecting who accessed the system and when—are retained indefinitely. Although this practice may support internal accountability, indefinite metadata retention could raise Fourth Amendment concerns, particularly in light of the U.S. Supreme Court’s ruling in Carpenter v. United States (2018), which recognized that long-term location tracking constitutes a search requiring a warrant.
Due Process and Risk of Misidentification
Councilmember Sarah Parady, a vocal opponent of the proposed contract expansion, has raised concerns about the potential for false positives and wrongful arrests. ALPR systems, while technologically advanced, are not immune to misreads or outdated alerts. If law enforcement relies solely on system-generated hits, individuals may be subject to stops or arrests without sufficient corroboration—potentially violating their due process rights.
Moreover, Parady and others argue that storing thousands of scans unrelated to any criminal activity amounts to bulk data collection that exceeds the reasonable scope of law enforcement authority.
Balancing Public Safety with Privacy
Denver Mayor Mike Johnston has defended the program, stating that the proposed expansion will enhance the city’s ability to address auto theft “without sacrificing our shared values and residents’ privacy.” ALPRs remain a core component of the administration’s crime prevention strategy.
However, legal precedent has consistently affirmed that efficiency in policing does not override constitutional protections. Courts have become increasingly skeptical of programs that enable law enforcement to conduct broad data collection without individualized suspicion, clear retention limits, or meaningful oversight.
Oversight and the Role of the Public
The American Civil Liberties Union of Colorado has also weighed in, emphasizing that decisions regarding surveillance technologies should be subject to public deliberation. “The community should have a say in whether or not they are willing to give [their privacy] up,” said Anaya Robinson, the ACLU’s senior policy strategist.
As it stands, 81 law enforcement agencies across Colorado currently have access to DPD’s ALPR data. The implications of this contract amendment will therefore extend well beyond Denver’s city limits, potentially setting a statewide precedent for the governance of surveillance technologies.
What’s Next?
The Denver City Council is expected to vote on the proposed amendment during its meeting on Monday. The decision will likely shape not only the future of ALPR deployment in the city but also the broader legal and ethical framework under which such systems operate.
In the coming days, stakeholders from across the legal, civil rights, and technology sectors will be watching closely. This is not just a procurement issue—it’s a test of how municipalities can or should balance the competing interests of security and civil liberty in an era of rapidly evolving surveillance capabilities.
