I built a demo of this back when I worked at Qualcomm in Seattle; match this with WiFi beacons and you can trace a person fairly well. It's been over a decade, but at the time both iOS and Android would send pings fairly frequently to all known WiFi networks looking to see if they should switch to a faster one. With your device ID, list of SSIDs you know, and your TPMS data, a person can learn a lot about you.

Like, where do you work? Where do you stay (Hotel SSIDs)? Who are your friends (other people's home SSIDs)?

I have an RTL SDR setup in a retail business receiving temperatures from sensors around the property. Besides the neighbors' weather stations I see a lot of TPMS coming, presumably, from the parking lot. I see the same cars regularly. I could definitely correlate them with the POS terminals and identify individual customers.

Maybe a buying trip north of the border might suit some U.S. folks alarmed by the TPMS blabbermouth data. Although Canadian-spec new vehicles usually have TPMS monitoring, it is not mandated, so some vehicles will display a dashboard icon or menu warning if no TPMS signal is seen, while others will just ignore the issue. Given that many Canadian consumers have dedicated sets of winter and summer tires/wheels, this is sensible to not require TPMS systems. Caveat emptor: I have no idea whether recertifying a new Canadian vehicle for the U.S. (i.e. changing kph speedo to mph, etc) involves flashing such different software.

You aren't gonna infer much from the passive tire rotation calculation based TPMS that the "designed to a price point" cars tend to use these days.

But I guess you don't really care about tracking people who drive cheap cars, for they have less surplus resources for you to convince them to part with so they're less of a priority to track...

With sufficient pressure resolution and monitoring, one could probably match movement patterns to road maps and know everything.

Thought this was going to be about reading the road like the groove on a record player. Apparently it is about cleartext radio signals and vehicle-specific identifiers.