Patent ID: 8548729

Claim:
A radio apparatus mounted on a vehicle, comprising: an acquiring unit configured to acquire positional information of the vehicle; a first predicting unit configured to predict an intersection, which the vehicle will enter, by associating positional information acquired by the acquiring unit and map information; a second predicting unit configured to predict whether another vehicle enters the intersection predicted by the first predicting unit by acquiring the positional information of the other vehicle included in a packet signal from another radio apparatus mounted on the other vehicle and associating the positional information of the other vehicle with the map information; a third predicting unit configured to predict whether travel of the other vehicle has an effect on this vehicle based on traveling direction information of the other vehicle acquired from the packet signal when the second predicting unit predicts entrance of the other vehicle; and a notifying unit configured to notify presence of the other vehicle when the third predicting unit predicts presence of the effect, wherein the third predicting unit predicts whether travel of the other vehicle has an effect on this vehicle by predicting whether the course of this vehicle is overlapped with the course of the other vehicle.