PURPOSE: To inform the running, slow movement, stoppage or the like of an automobile to the outside, by providing horizontally-moving color changers on the insides of upper sections of front and rear windshields.

CONSTITUTION: Horizontally-moving color changers 1, 2 are mounted on the insides of upper sections of the front and rear windshields of an automobile or the like. When the automobile is running, the color changers 1, 2 are lighted entirely blue. When the driver puts his foot on the brake pedal for braking, the blue-lighted color changers 1, 2 turn orange in at least half of the legnth from the left to the right looking at the front of the automobile. When the driver depresses the brake pedal, the orange-lighted section of each color changer extends depending on the deceleration to inform the following cars, other cars running in the opposite direction, pedestrians, etc. of how much force is braking the automobile. When the vehicle is thereafter stopped, the color changers 1, 2 turn entirely orange to inform that the vehicle is stopped.