S.C. Code Ann. § 56-2-3070

(A) A person may not ride upon a moped other than upon or astride a permanent and regular seat attached to the moped. A moped may not be used to carry more persons at one time than the number for which it is designed and equipped by the manufacturer to carry. (B) A moped, while traveling along a multilane highway, must be operated in the farthest right lane except when making a left turn or when travel in the farthest right lane is unsafe. (C) A person under the age of twenty-one may not operate or ride upon a moped unless he wears a protective helmet identical to underage motorcycle helmet requirements provided in Section 56-5-3660. (D) A person may not operate a moped at a speed in excess of thirty-five miles per hour. (E) A person may not operate a moped on a public highway that has a speed limit of greater than fifty-five miles per hour. A person operating a moped may cross an intersection at a public highway that has a speed limit of greater than fifty-five miles per hour. (F) The operator of a moped must have turned on and in operation the operational lights and the headlight at all times while the moped is in operation. (G) A person who violates the provisions of this section is guilty of a misdemeanor and, upon conviction, must be fined not more than two hundred dollars or imprisoned not more than thirty days.