Would such a device connect to a battery? Is there a vehicle-tracking unit that also has this function built in, in order to somehow track both the driver and the vehicle?
I am unaware of such a product. Today's cars include a high-frequency (HF) RFID reader in the steering column. This is used to detect that an authorized key is being used. If a key is copied illegally, or if someone tries to start a car without the key, the RFID reader will prevent the vehicle from starting. This was introduced about 15 years ago as an anti-theft device. It could be possible to identify people via different keys—but, of course, people could switch keys.
It would not be difficult to install an interrogator in the dashboard to determine who was driving the car. This might be useful for adjusting the temperature and seat. The reader could identify a transponder in a keychain fob, for instance. But you would have the same problem as above, with people switching keys. To truly identify the person driving, you would need some way to associate a tag with that person permanently, and that is something to which many people would object.
—Mark Roberti, Founder and Editor, RFID Journal