PURPOSE: To obtain various informations from a road by constructing to enclose an electrode in the outer periphery of a car tire to be in contact with the electrode of a transmitting electric circuit laid on the road for receiving signals.

CONSTITUTION: An electrode 2 is enclosed in the tread part on the outer periphery of a tire 1, and connected to a side terminal 4 via an inner lead wire 3. This tire 8 is brought in contact with an electrode 7 laid on a road face 6 for forming an electric circuit. Consequently, a signal 12 of a transmitter 11 on the side of the road face 6 is sent to a receiver 10 on the side of a car body 5 via the electrode 2 of the tire 8 to be recognized by a driver. This construction permits to inform of the information in a dangerous area or the like previously and improve the safety.