Your Car Has a Wireless Fingerprint That Has Nothing to Do With Your Plate
Most people think license plate readers are a car problem. Cover your plate, swap your vehicle, borrow a friend’s car…and you’re off the grid.
That may not be enough…
A $17 billion Italian defense contractor called Leonardo quietly patented a system in March 2024 that clips sensors directly onto existing license plate reader hardware.
The sensors don’t read your plate as you would think…they read your phone, smartwatch, AirPods, and your car’s tire pressure sensors.
Every device you travel with that broadcasts a wireless signal gets logged, correlated, and stored.
Over time, the specific combination of devices you carry becomes a unique electronic fingerprint…one that can identify you and your vehicle even when there’s no plate to read.
The system is called SignalTrace. And the infrastructure it runs on is already everywhere.
What SignalTrace Actually Is
Leonardo US Cyber and Security Solutions, a subsidiary of Leonardo S.p.A., Italy’s largest defense company, markets SignalTrace as an add-on to its existing ELSAG license plate reader platform.
The ELSAG system already operates in thousands of jurisdictions across the United States. SignalTrace basically upgrades these readers.
The patent, US 11,941,716 B2, titled “Systems and Methods for Electronic Signature Tracking,” describes a system that captures device-frequency activity from passing vehicles and correlates it with plate data inside a centralized system called the ELSAG Enterprise Operations Center (EOC).
Everything gets timestamped, geotagged, and indexed for later search.
The device categories Leonardo’s own product sheet lists include: RFID tags, Bluetooth devices, vehicle components, and Wi-Fi sources.
The specific examples: key cards, asset tags, pet microchips, mobile phones, watches, fitness trackers, wireless headphones, tire pressure sensors, infotainment systems, vehicle hotspots, tablets, smartphones, and laptops.
Leonardo’s position is that the system captures publicly broadcast signals and doesn’t decrypt communications content.
That’s technically accurate. It’s also beside the point.
The Part Most Coverage Is Missing
The privacy argument people are having about SignalTrace focuses on whether capturing your Bluetooth ID is legal.
That argument matters, but it’s the wrong place to focus if you’re thinking about your own exposure.
Here’s the thing that should get your attention: your car itself is broadcasting.
Tire Pressure Monitoring Systems (TPMS) have been federally mandated on all vehicles sold in the United States since 2008. Each tire sensor broadcasts a unique identifier every few seconds when the vehicle is in motion.
That signal doesn’t require your phone or your Bluetooth to be on.
It actually doesn’t require any action on your part.
The full breakdown, including the specific signals your vehicle broadcasts independently of any device you carry, what the current legal landscape actually allows, and five concrete steps to audit and reduce your electronic signature, is available to paid subscribers. Join Prepared Brief to read the rest.
