New surveillance tech links phones to license plates

A new surveillance technology called SignalTrace, developed by the security company Leonardo, is designed to link broadcast electronic signals from devices like phones and smartwatches to license plate reader data. The system aims to help investigators track movements and associations of individuals by recognizing recurring patterns of devices traveling together, even if the individuals' identities are not initially known.

SignalTrace works by detecting signals such as Bluetooth or radio frequency identification tags. While Leonardo states the system does not directly identify people and only collects electronic signatures, privacy advocates argue that these signatures can be linked to other information, such as vehicle registration records and home locations, to infer identity. This approach shifts investigations towards people's movements and associations before their identities are established.

The technology's effectiveness is highlighted by research showing that even a few time-and-place points from mobility data can uniquely identify a large percentage of individuals. The Supreme Court has also recognized a reasonable expectation of privacy in phone location records, as seen in cases like Carpenter v. United States and Chatrie v. United States, which dealt with the Fourth Amendment implications of obtaining location data.

While SignalTrace is marketed as a tool to develop investigative leads, its ability to track individuals based on device proximity and movement patterns raises significant privacy concerns. The system's reliance on association, without knowing the reason for proximity, means that individuals could become subjects of investigation based on where their devices appear and who they appear near, irrespective of initial suspicion.