License plate readers may soon track iPhones and AirPods

My notes

Summary

Leonardo US is marketing “SignalTrace,” a sensor add-on that bolts Bluetooth, Wi-Fi and RFID scanners onto existing automatic license plate reader (ALPR) cameras. It builds a database of the wireless signals your phone, AirPods, smartwatch and fitness trackers emit in public, then links those device fingerprints to camera data to detect who travels together. No warrant requirement is mentioned, and there is no state or federal oversight of the private company holding the data.

Key Insight

• Your devices broadcast identity, not just your car. SignalTrace fingerprints people via passive RF emissions (Bluetooth/Wi-Fi/RFID), AirPods, smartwatches, fitness trackers, RFID tags, and ties them to ALPR camera hits. The car is no longer needed to track you.
• The real product is the “convoy” graph. Value isn’t a single ping, it’s pattern detection: two phones consistently seen together flags “convoys and movement patterns.” This is relationship mapping, not just location.
• Scale already exists. SignalTrace’s ALPR predecessors (formerly Elsag EOC Plug) are deployed to “nearly 4,000 customers in over 25 countries.” The Bluetooth-scraping layer is so new it may not yet be purchased by any state, the install base is the distribution channel.
• Oversight gap is the story. Leonardo claims it doesn’t decrypt content and only shares on law-enforcement request, but cites no warrant requirement. EFF reported (Nov 2025) 50+ agencies used prior ALPR networks to surveil protesters and activists.
• Legal fault line: the “no expectation of privacy in public” argument vs. a private firm holding personal movement data with no statutory oversight, bound to be litigated.