Patent ID: 8760320

Claim:
A communication apparatus, which is used in a system in which vehicle information is periodically transmitted and received between vehicles, and is installed in the vehicles, comprising: a time information obtaining unit which obtains a current time; a state information obtaining unit which repeatedly obtains state information which represents a state of an own vehicle at the current time and includes a current position of the own vehicle, a traveling speed of the own vehicle, and a traveling direction of the own vehicle; an own vehicle information generating unit which estimates predicted arrival positions representing positions of the own vehicle at specific times, which are specified by specific time intervals between the current time obtained by the time information obtaining unit and a specified time, which is a specified time length, on the basis of the state information obtained by the state information obtaining unit, and which repeatedly generates own vehicle information including the current position of the own vehicle included in the state information and the predicted arrival positions; an information transmitting unit which transmits the own vehicle information generated by the own vehicle information generating unit; and an information storage unit which stores the own vehicle information transmitted by the information transmitting unit into a first storage section as past own vehicle information, wherein the information transmitting unit obtains, every time the own vehicle information is generated by the own vehicle information generating unit, an information coincidence degree representing the degree of the coincidence between current own vehicle information which is the own vehicle information generated by the own vehicle information generating unit and the past own vehicle information stored in the first storage section, and stops transmitting the current own vehicle information if the information coincidence degree is not less than a specified threshold.