Pennants, a banner (other than a grand opening banner), sandwich boards, and/or a temporary ground sign is permitted accessory to a commercial establishment in the I-1, I-2, O-1, O-2, B-1, B-2, B-3, B-4, and B-5 Zoning Districts for a total of eight weeks in any calendar year for notification only of special events, special promotional purposes, temporary sales, grand openings, etc., provided that such pennants, banner, sandwich boards or temporary ground sign does not cause a danger to the general public in accordance with § 296-162G or otherwise impede sight triangles or foot traffic during business hours.