Your Tire Pressure Sensors Are a Secret Tracking Device

Privacy-conscious individuals do their research to ensure that their phones, computers, smart speakers, and security cameras are not spying on them. This is a tough job, not only because many of these devices are black boxes, but also because of the sheer number of gadgets out there these days that are capable of collecting private information about us.

Unfortunately, this problem is getting worse, not better. A recently published study has revealed that even our cars can spy on us. You might not be shocked about this finding if you are driving a modern car that is connected to the internet. However, the problem extends to older vehicles as well. Nearly any car manufactured in the past twenty years can be uniquely identified and tracked by hidden monitors.

The culprit is not a cellular modem or a built-in navigation system, but the Tire Pressure Monitoring System (TPMS). Originally introduced as a safety feature and now mandatory in many countries, TPMS sensors sit inside each tire and periodically transmit wireless signals containing pressure data to the vehicle’s control unit. These transmissions, it turns out, are sent in clear text and include a unique identifier that typically remains unchanged for the lifetime of the tire.

In the study, researchers deployed five low-cost Software-Defined Radio (SDR) receivers along a neighborhood roadway over a period of ten weeks. Each receiver cost roughly $100, making the setup affordable and easy to replicate. During the experiment, the team collected more than six million TPMS messages from over 20,000 vehicles, including 12 cars whose identities were verified for deeper analysis.

Although TPMS signals are relatively weak and can usually be intercepted from distances of up to about 40 meters, the researchers demonstrated that a distributed network of receivers can still build detailed movement profiles. By developing algorithms to associate the four tire sensors of a single vehicle, they were able to reliably identify individual cars as they passed multiple monitoring points.

Through pattern matching and data mining techniques, the team showed that it is possible to infer potentially sensitive information about drivers. For example, consistent travel times and routes can reveal daily routines. Variations in signal characteristics may hint at the presence of additional passengers or cargo weight. Over time, this data can paint a very detailed portrait of a person’s habits.

Unlike high-profile data breaches involving automakers or navigation services, TPMS tracking does not require access to corporate servers or cooperation from the vehicle owner. Any motivated individual with modest technical skills and inexpensive radio hardware could potentially deploy a similar monitoring network.

This work is a reminder that even systems designed purely for safety and maintenance can introduce unexpected privacy risks. Policymakers and manufacturers may now need to rethink how even the smallest wireless signals from our vehicles are designed, secured, and regulated.