For those without toll roads (road you pay to drive on), EZPass (and other systems in different states) is an automated payment system. You drive through a toll booth, a special transceier 'reads' the tag and identifies who it belongs to, then deducts the toll amount from an account you have set up with the highway authority.
These things are called RFID tags - Radio Frequency Identification. If you want to get really detailed on how they work, Google it.
Now radio frequencies have a hard time passing through a lot of metal (think about how a cell phone doesn't work in a metal elevator), and a lot of cars are embedding metal into the glass for tinting, etc. Hence the need for external tags.
tzn2004 - try a little experiment to determine if you even need the external tag. Drive slowly into the booth with the tag on your dash or held up to the windshield. If the booth detects the tag, then you don't need the external one. If it doesn't detect it, roll down the window and wave it around - it'll detect it then.
Can you tell I'm an engineer yet?
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1998 Camry LE V6 --- 149,900 miles and counting...
Jobs done so far:
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