| 摘要 |
A radio frequency system comprising a radio frequency identification (RFID) tag mounted in or on a road surface. An RFID tag reader for reading the tag is located above the RFID tag so that when a vehicle is traveling along the road surface and the tag is at least partially located between the RFID tag reader and the RFID tag, the RFID tag reader is then unable to read the RFID tag but when there is no vehicle located between the RFID tag reader and the RFID tag the RFID tag reader is able to read the tag. |
