License Plate Cameras Are About to Get a Lot More Invasive
If you thought automatic license plate readers (ALPRs) were already a significant privacy concern, brace yourself. A new surveillance technology called SignalTrace, developed by defense contractor Leonardo, is set to dramatically expand what these roadside cameras can do. Beyond capturing your license plate, SignalTrace-equipped systems will soon be able to scrape the unique identifiers of your smartphone, smartwatch, AirPods, AirTags, and even your car's infotainment system — and hand that data directly to law enforcement agencies.
This development marks a significant escalation in the already heated debate around public surveillance, digital privacy, and the growing power of data brokers. Understanding what SignalTrace is, how it works, and what it means for everyday citizens has never been more important.
What Is SignalTrace and Who Is Behind It?
SignalTrace is a product being actively promoted by Leonardo, a major international defense and aerospace contractor. According to a detailed investigation by 404 Media, the technology bundles traditional ALPR cameras with additional sensors capable of detecting and logging the unique device identifiers broadcast by the wireless electronics you carry with you every single day.
Leonardo's existing customer base already includes police departments, border security agencies, and various other government bodies. With SignalTrace, the company is marketing a powerful upgrade to the surveillance infrastructure those clients already rely on. The pitch is straightforward: correlate a vehicle caught on camera with every wireless device inside or near that vehicle at the same moment.
The implications are staggering. When you drive past one of these cameras, the system wouldn't just record your plate — it could also log the Bluetooth signal from your wireless earbuds, the Wi-Fi probe requests from your phone, the unique identifier broadcast by your Apple Watch, and the cellular radio from your tablet sitting on the back seat.
Which Devices Can SignalTrace Actually Track?
The scope of what SignalTrace is designed to detect goes far beyond just smartphones. Promotional materials suggest the system is engineered to pick up signals from a remarkably wide range of consumer devices, including:
- Smartphones and tablets — the obvious starting point, as these broadcast multiple wireless signals simultaneously via Bluetooth, Wi-Fi, and cellular networks.
- Wearables — smartwatches, fitness trackers, and wireless earbuds like AirPods constantly emit Bluetooth signals that carry unique identifiers.
- AirTags and similar tracking devices — small Bluetooth trackers used by millions of people to keep tabs on keys, luggage, and valuables.
- Vehicle infotainment systems — modern cars have built-in Bluetooth, Wi-Fi hotspots, and even 5G connectivity, all of which broadcast identifiable signals.
- Tire pressure monitoring sensors (TPMS) — every modern vehicle is legally required to have them, and they transmit unique radio frequency signals that could serve as a secondary vehicle identifier even if a plate is obscured.
- Pet microchips — perhaps the most surprising entry on the list, Leonardo has reportedly cited pet microchips as a potential data point the system could capture and correlate.
The breadth of this list underscores a troubling reality: in the modern world, nearly every object around you is broadcasting some form of wireless signal. SignalTrace is designed to harvest as many of those signals as possible and weave them into a coherent surveillance profile.
Why This Is a Major Privacy Threat
The core danger of technology like SignalTrace lies in what data brokers and law enforcement can do with correlated data over time. A single snapshot of your license plate tells authorities relatively little. But pair that plate with the consistent Bluetooth MAC address of your iPhone, and suddenly every ALPR camera in a city becomes a node in a network capable of tracking your movements with frightening precision.
If a data broker can link your devices to your vehicle, they effectively know where you live, where you work, which places of worship you attend, which medical facilities you visit, and who you spend time with. That data, once collected, can be sold, subpoenaed, hacked, or misused in ways that are extraordinarily difficult to predict or prevent.
Privacy advocates have long warned that ALPR databases already constitute a form of mass surveillance, building up detailed movement histories on millions of innocent people who have never been suspected of any crime. SignalTrace would supercharge that capability by adding a persistent, device-level identity layer on top of the existing vehicle-level tracking infrastructure.
The Legal and Regulatory Landscape Is Struggling to Keep Up
Currently, the legal framework governing ALPR data collection in the United States remains fragmented and inconsistent. Some states have enacted laws limiting how long plate reader data can be retained or who can access it, but there is no comprehensive federal standard. The addition of wireless device tracking into this ecosystem introduces an entirely new category of data that existing regulations were never designed to address.
Questions abound. Does scraping a Bluetooth identifier from a passing car constitute a search under the Fourth Amendment? Can that data be retained indefinitely? Can it be shared with federal agencies, foreign governments, or private contractors? The courts and legislatures have not yet answered these questions, and technology like SignalTrace is advancing far faster than the legal system can respond.
What Can You Do to Protect Yourself?
While no solution is perfect, there are practical steps individuals concerned about this type of surveillance can take to reduce their exposure. Turning off Bluetooth and Wi-Fi when not actively using them limits the number of signals your devices broadcast. Some smartphones also include settings that randomize the MAC address used for Wi-Fi scanning, which reduces the usefulness of that identifier for long-term tracking. Being aware of where ALPR cameras are concentrated in your area can also help inform decisions about your routes and routines.
However, the responsibility for protecting privacy should not fall entirely on individuals. Advocacy groups, policymakers, and civil liberties organizations need to push for clear, enforceable regulations around the collection and use of wireless device identifiers in public spaces before technologies like SignalTrace become as ubiquitous as the license plate cameras that already line roads across the country.
The Bottom Line
SignalTrace represents a meaningful leap forward in the capabilities of public surveillance infrastructure. By combining the already-widespread network of ALPR cameras with sensors that can identify your phone, your smartwatch, your car's electronics, and even your pet's microchip, Leonardo is offering law enforcement a tool that blurs the line between targeted investigation and mass monitoring. As this technology moves closer to deployment, the conversation around digital privacy, data broker regulation, and the limits of government surveillance has never been more urgent.
Stay informed, advocate for stronger privacy laws, and pay close attention to how surveillance technology continues to evolve — because the cameras on the side of the road are paying very close attention to you.