Driving with RFID

It occurred to me, as I drove from Arkansas to Utah last week, that if my car or something in my car (like me) was outfitted with an RFID tag with a good enough range, my progress across the country could be tracked for varying reasons. For instance, my family waiting for us in Utah as we plod through the midwest snowstorms could log into a Web site and track our progress, much like tracking a package with UPS or FedEx. A series of highway overpasses would just need RFID readers on them and we would just pass under or through these "portals" and our progress would be logged into a Department of Transportation database.

Then I wondered why the computer wouldn't also say "It appears that your average speed between underpass exits 301 and 304 was 87.3 miles per hour. Expect a traffic ticket in the mail for exceeding the posted speed limit."