Existing license plate readers already scan thousands of plates per minute across American roads. Now defense contractor Leonardo US wants to bolt wireless sensors onto that same infrastructure. The company’s ELSAG SignalTrace system, first reported by 404 Media, adds Bluetooth, Wi-Fi, and RFID collection to standard plate cameras — harvesting identifiers from every consumer device in range. Your car becomes a rolling inventory of trackable signals. No federal law explicitly prohibits it. Researchers have also documented how a surveillance app was built by US operatives to target political dissidents, illustrating how quickly this kind of tracking infrastructure can be turned against civilian populations.
One Camera, Everything You’re Carrying
SignalTrace sweeps device identifiers from phones, wearables, car systems, and even pet microchips to build unique “electronic fingerprints.”
Drive past an equipped sensor and SignalTrace reportedly captures identifying details from your smartphone, smartwatch, wireless earbuds, in-car infotainment, tire pressure monitors, Wi-Fi hotspots, RFID access cards, and — yes — your dog’s microchip. Leonardo’s own product materials offer a telling example: among 100 cars, only one consistently pairs an iPhone 13rev2 with an Audi radio, Bose headphones, a Garmin watch, and plate ABC-1234. That combination becomes a uniquely searchable fingerprint.
The devices SignalTrace targets include:
- Smartphones and tablets via Bluetooth and Wi-Fi probe requests
- Wearables like fitness trackers and wireless earbuds
- Vehicle electronics including infotainment units and in-car hotspots
- RFID objects from luggage tags to pet microchips
- The system doesn’t need a plate number first — it can identify a vehicle by its device cluster alone
Standard plate readers track cars. SignalTrace tracks people. Leonardo markets this explicitly as “bridging the gap” between vehicle and occupant, according to its product materials. Even if someone swaps or obscures a plate, the device fingerprint follows the person, not the vehicle. “Identifies the movements of electronic devices, individuals, and vehicles” — Leonardo US product materials.
The “Metadata Only” Defense Won’t Save You
Leonardo says it captures only broadcast signals, but critics argue location metadata builds a far more damaging dossier than message content ever could.
Leonardo claims SignalTrace “does not decrypt or read the contents” of any device communications — just publicly broadcast signals, no different from reading a plate number. Think of it as your surveillance Spotify Wrapped: a devastatingly detailed portrait assembled entirely from behavioral data, not confessions. The ACLU has documented that plate readers alone already “create permanent records of virtually everywhere any of us has driven.” Layer device fingerprints on top and you get home addresses, workplaces, medical visits, and social associations — without a warrant.
Under current law, this sits in a regulatory vacuum. State ALPR statutes were written for plate images, not mass Bluetooth harvesting, leaving SignalTrace in a legal gray zone. Leonardo pitches retail crime prevention as a secondary use case, but technologists warn that mission creep follows infrastructure — tools sold for shoplifting investigations can be quietly repurposed for routine policing or immigration enforcement once the sensors are in place, according to 404 Media reporting. A separate investigation found that a White House app was caught secretly tracking users every four minutes, a reminder that location metadata builds a far more damaging dossier than message content ever could.
Disabling Bluetooth helps in theory, but most infotainment systems re-enable radios automatically and MAC randomization remains imperfect. SignalTrace tracks the full device bundle — not any single signal — leaving no practical opt-out. It’s the cookie consent banner of the physical world, except nobody even shows you the banner.
The question isn’t whether this infrastructure expands. It’s whether any law catches up before it does.
