Ключевые слова: angle, attention, background, blue, caution, center, clouds, color, communication, concepts, control, danger, direction, forbidden, highway, image, information, isolated, law, low, message, metal, nobody, object, octagon, outdoors, red, road, roadside, roadsign, safety, shape, sign, signal, sky, speed, stop, street, sunlight, symbol, text, traffic, transport, transportation, travel, vertical, view, warning, white, word,