S.C. Code Ann. § 57-25-140
(A) An outdoor advertising sign must not be erected or maintained after June 30, 1975, which is visible from the main-traveled way of the interstate or federal-aid primary highways in this State and erected with the purpose of its message being read from the traveled way, except the following:
(D) No sign permitted under this section may obscure or otherwise interfere with the effectiveness of an official traffic sign, signal, or device nor obstruct or interfere with the driver's view of approaching, merging, or intersecting traffic. No sign except on premises and FOR SALE or LEASE signs may be located within three hundred feet of any of the following which are adjacent to the highway in areas outside of incorporated municipalities or within one hundred feet on sections inside municipalities:
(H) Whenever a bona fide county or local zoning authority has made a determination of customary use, which includes a regulation of size, lighting, and spacing of outdoor advertising signs, in zoned industrial or commercial areas, the determination prevails over the size, lighting, and spacing otherwise provided for the signs in subsections (C) and (E) if all of the following exist:
(3) The zoning plan and amendments are submitted to and approved by the Department of Transportation before they prevail over the standards set forth in this section.
Zoning which controls contiguous tracts which comprise less than twenty percent of the land within a political subdivision or land which is zoned primarily to permit outdoor advertising signs is not considered zoning for the purposes of this section.
(I)
(2) If vegetation is removed from within a highway right-of-way without a permit by the sign owner or his agent and the removal has the effect of enhancing the visibility of the outdoor advertising sign, the sign is illegal and must be removed at the responsible party's expense. Upon a violation of this subsection the responsible party is not eligible for a sign permit: