Is there any device available that would allow drivers to monitor the number of tolls they pass—something like a reader of a reader?
To my knowledge, there is no such device. I have seen devices on the market that can detect ultrahigh-frequency (UHF) radio waves from a passive UHF RFID reader, but most toll booths employ active RFID systems. You would need some kind of simple, battery-powered spectrum analyzer to determine whether radio waves at a certain frequency were reaching your car. I have never seen such a device available for sale, however. If any of our readers have any suggestions, they are welcome to post information below.
—Mark Roberti, Founder and Editor, RFID Journal