Using Tire Pressure Sensors To Spy On Cars

AngryDad writes "Beginning last September, all vehicles sold in the US have been required to have Tire Pressure Monitoring System (TPMS) installed. An article up at HexView enumerates privacy issues introduced by TPMS, and some of them look pretty scary. Did you know that traffic sensors on highways can be adopted to read TPMS data and track individual vehicles? How about an explosive device that sets itself off when the right vehicle passes nearby? TPMS has been discussed in the past, but I haven't seen its privacy implications analyzed before. Fortunately the problem is easy to fix: encrypt TPMS data the way keyless entry systems do."

Re:RFID tracking

[nguy]

Using RFID combined with detectors at every street corner will allow for constant surveillance of every car all the time.

So do license plate readers, and they can operate from greater distances and completely passively. Cost for a license plate reader is about the same as a good RFID reader, and they are probably at least as reliable. Furthermore, you are required to keep your license plate readable.

Some cities are already starting to implement complete license plate-based tracking of vehicles.

Re:RFID tracking

[everphilski]

Kinda hard to do without puncturing the tire. Read up on it: here [hanarfid.com]. Michelin at least seems to mount it inside the laminas of the tire.

Of course you could always surround your tires in tin foil if you are THAT paranoid.

Re:RFID tracking

[timeOday]

You better tell these guys [platepass.com] because their business is OCR'ing license plates. It's not research. I rent cars from Avis in Orlando fairly regularly and they have this option right now.

Re:RFID tracking

[Anonymous Coward]

What I am worried about is the RFID tags embedded in Reynolds Wrap.

Re:RFID tracking

[afaik_ianal]

Of course, cars also come with this thing called a "license plate", which can also be tracked remotely and wirelessly.

I don't know about "wirelessly" unless you are talking about people using their eyeballs.

On Australian highways (In my state of New South Wales, at least), we have special cameras located on overpasses and things every couple of hundred kilometres or so. These most definitely detect where the number plates are in the image, cut them out, perform OCR, then record the ones that are on trucks. It's used to enforce the laws preventing truckers from driving too far without sleep, and constant speeding.

These cameras have been around for over 10 years, and I assure you, are highly accurate.

Probably not a 4/1 story.

[gardyloo]

Here (at the end of this post) is the text of the applicable document summarizing the TREAD act.
http://www.tireindustry.org/pdf/TREAD_Act_Summary.pdf [tireindustry.org]

    Looks to me that no one is requiring continual monitoring (and reporting) of tires' conditions; only when the tire pressure falls below 25% of recommended cold pressure is a signal required to be sent (and I see nothing about being able to tell which car in a fleet has the problem from outside the car itself).

    Finally, article summary should say "all NEW vehicles sold in the US" require the system, not "all vehicles sold in the US".

The final rule was published June 5, 2002. Unfortunately NHTSA
proposed that if a vehicle is using a direct system (with sensors in each
tire sending a signal to the dashboard) the TPMS does not have to trigger
until the tire is 25 percent below the recommended cold psi. An indirect
TPMS (that runs off the anti-lock braking system) does not have to
trigger until the tire is 30 percent below the recommended cold psi for
that tire. TIA is strongly opposed to NHTSA's supposed "safety"
regulation which in effect allows the motoring public to drive on severely
underinflated tires. TIA has supported a petition that NHTSA mandate
reserve inflation pressure in tires to offset the TPMS rule. [See letter to
NHTSA supporting petition.]

Hamsters

[Pseudonymus Bosch]

Getting groceries home will be a bitch tho...

Didn't hamsters solve that by carrying food in their cheeks?

How the new TPMS sensors work.

[Anonymous Coward]

Basically, the new mandated TPMS sensors are all direct sensors. These sensors have been mandated as of the 2007 model year on all cars sold in the US. (There are a large number of cars sold in Canada that use this system too, but it is not mandated in Canada). Indirect systems (the ones that use the ABS sensors) are not allowed under the mandate as they were deemed too inaccurate. The TPM system is mandated to notify the driver once there is a 25% loss of pressure from nominal from the tire. Many systems also indicate a high pressure warning also.

Most car companies have been developing the technology for over a decade. GM started in the mid 90's on the corvette.

Most systems use a pressure sensor internally mounted to the rim on the valve stem. The valve stem acts as the antenna for the transmitter. (Look for cars with aluminum coloured valve stems, these are TPMS equiped vehicles.) The transmitter will transmit at the same frequency as your key FOB. This allows the car companies to minimize the amount of extra equipment required for the system. Most systems probably only require the sensors and a reprogramming of the requisit computers in the car.

Pay close attention to the shop that changes your tires. Many shops are poorly trained in dealing with TPMS sensors and tell many lies about the systems as they don't understand how they work.

The sensors typically operate under a pretty simple algorithm. Basically, when the car is stationary the sensors will transmit every hour. If the car starts moving above a certain speed they sensors will start to transmit every minute. If the pressure in the tire suddenly changes more then a certain amount, the sensor will transmit the new pressure immeditatly. Each sensor has a unique ID to permit the computer to identify which corresponds to which pressure. The car's computer will be programmed to listen for these transimssions. Should the car fail to receive a transmission from a specifc tire over a certain period of time, then the computer will indicate there is a malfunction of the system.

Because the sensors have unique IDs it is typically required to relearn the sensor locations after a tire rotation. There are many different releasern procedures. You can set the car into learn mode and triger each sensor by letting air you of the tires or you can use a specific TPMS tool to triger the sensors using a LF magnetic field.

These systems are all pretty straight forward once you know how they work. Most people are afraid of new technology, but in most respects this is pretty simple stuff that any modern mechanic should have no problem working with.

Re:RFID tracking

[plague3106]

Because if they actually ticketed everyone that broke the speed limit law, government would finally be forced to raise speed limits... especially since Australia is likely in the same spot as the US; illegally setting limits lower than dictated by civil engineers for the purpose of raising revenue and pushing more draconion measures on drivers.