Ключевые слова: area, asphalt, background, barricade, barrier, boundary, concert, construction, control, crowd, entrance, equipment, event, fence, gate, gray, grille, guard, heat, industrial, iron, line, lonely, long, metal, mobile, nobody, police, preparation, protection, regulation, row, safety, security, sidewalk, stadium, stand, steel, stop, street, summer, system, traffic, turnstile, white, zone,