An environmental movement detection section detects the speed of a vehicle and detects a mobile object in the vicinity of the vehicle. A collision probability prediction section predicts the probability of a prospective collision between the vehicle and the detected vicinity mobile object. On the basis of approach speeds, collision probabilities and sideward passing speeds when passing other mobile objects to sideward that have been determined from standard movements, a movement standard learning section learns relationships between approach speed, collision probability and sideward passing speed. On the basis of learning results at the movement standard learning section, a path characteristic point generation section determines a standard sideward passing speed for when passing the vicinity mobile object to sideward that corresponds with the detected approach speed and the predicted collision probability. Thus, standard mobile object states may be determined efficiently.