S.C. Code Ann. § 57-7-230: Speed-control devices in certain areas not deemed obstructions.

(1) Municipalities or counties may, upon roads and streets in residential areas or school zones, construct and maintain speed-control devices as they deem necessary upon the basis of an investigation of the area. Such devices shall consist of a mound, rib or hump with sloping sides, extending across a road or street, and not exceeding six inches in height above the street or road surface. Provided, however, the speed limit in any such area shall be posted at twenty-five miles per hour or less and signs shall be erected warning of the existence of the devices.

(2) Speed-control devices, when constructed and posted according to this section, shall not be deemed obstructions of the road or street, and no action may be brought on behalf of any party against a municipality or county for damages occasioned thereby.