Patent ID: 8447484

Claim:
A branch-lane entry judging system comprising: traffic-line detecting means configured to detect traffic lines on right and left sides of a vehicle; length and width detecting means configured to detect lengths and widths, in a traveling direction of the vehicle on a real space, of the traffic lines detected by the traffic-line detecting means; lane-type judging means configured to judge types of the traffic lines and judge a type of a lane in which the vehicle is running, on the basis of a result of detection performed by the length and width detecting means; branch-lane detecting means configured to detect the existence of a branch lane when detecting, on the basis of the result of detection performed by the length and width detecting means, that one of the traffic lines changes from a solid line to a broken line having a predetermined length and a predetermined width, the branch lane existing near the changed traffic line; branch-lane entry judging means configured to judge that the vehicle will enter the branch lane when the vehicle moves toward the branch lane, or when a directional indicator is operated toward the branch lane; control means configured to output a deceleration signal for decelerating the vehicle when: the length and width detecting means detects that both the traffic lines on the right and left sides of the vehicle have changed to solid lines, while a predetermined time passes or while the vehicle runs by a predetermined distance, after the branch-lane entry judging means judges that the vehicle will enter the branch lane; and history holding means configured to hold a sampling period history, said history including data representative of a traffic line status in a previous sampling period, wherein the system is configured to judge, with reference to the history held by the history holding means, that the one of the traffic lines changes from a solid line to a broken line.