Patent attributes
A collision possibility determining unit determines that a subject vehicle has possibility of colliding with a certain vehicle when both the following two determinations are fulfilled. The first determination is that the traveling state of the subject vehicle is proper. The second determination is that a relative position between the subject vehicle and the certain vehicle continues to be maintained at the same relationship for a given period. When the collision possibility is determined to be existing, an alarm generating unit generates an alarm that arouses driver's attention. Thus, collision possibility is determined based on the relative position relationship with another vehicle, so that an alarm relating to another vehicle as an obstacle can be generated at a proper timing.
