Patent ID: 8229668

Claim:
A vehicle communication system comprising: a host-vehicle information generating unit which generates running information of a host vehicle; a communication processing unit which transmits the running information of the host vehicle generated by the host-vehicle information generating unit in wireless communications and receives running information of other vehicles in wireless communications; a virtual region defining unit which defines virtual regions around the travelling direction of the host vehicle on the basis of the generated running information of the host vehicle; a traffic line determination unit which determines whether or not there are located the other vehicles the number of which is larger than a threshold value in front and rear regions in the running direction of the host vehicle among the defined virtual regions, on the basis of the received running information of the other vehicles and the generated running information of the host vehicle; and a transmission controlling unit which maintains a first transmission power when it is determined by the traffic line determination unit that the number of the other vehicles is smaller than the threshold value, and which controls to reduce the transmission power in wireless communications to a second transmission power lower than the first transmission power when it is determined by the traffic line determination unit that the number of the other vehicles is larger than the threshold value.