&gt; and all RFID tags of the same frequency will respond to the reader at the same time<p>Depends on the tag design. Using Q Values you can avoid the collisions to some extend. <a href="http:&#x2F;&#x2F;www.rfidsb.com&#x2F;anticipating-your-starting-point-with-the-q-value&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.rfidsb.com&#x2F;anticipating-your-starting-point-with-...</a><p>Not sure how much the spinning tires distort signals...etc. Def out of my scope of knowledge.<p>&gt; It makes no sense to attempt to use RFID for tracking cars.<p>Agreed, grabbing license plates makes more sense.