S.C. Code § 12-37-2850
The Department of Motor Vehicles shall assess annually the road use fee due on large commercial motor vehicles and buses based on the value determined in Section 12-37-2820 and an average millage for all purposes statewide for the preceding calendar year and shall publish the average millage for the preceding year by July first of each year. The Department of Revenue, in consultation with the Revenue and Fiscal Affairs Office, shall calculate the millage to be used to calculate the road use fee by June first of each year for the following calendar year. The road use fee assessed must be paid to the Department of Motor Vehicles, in addition to the registration fees required pursuant to Sections 56-3-660 and 56-3-670, at the time and in the manner that the registration fees on the vehicle are paid pursuant to Sections 56-3-660 and 56-3-670. Distribution of the fees paid must be made by the Office of the State Treasurer based on the distribution formula provided in Sections 12-37-2865 and 12-37-2870.
S.C. Code § 12-37-2850
2017 Act No. 40, Sections 8.L, 8.M, provide as follows:
"L. (1) Notwithstanding any provision to the contrary within this SECTION, a person who registers a vehicle for use in this State pursuant to Article 23, Chapter 37, Title 12, as amended by this act, must register his vehicle during calendar year 2019 and is required to pay the road fees calculated based on the fair market value of the vehicle as specified in Sections 12-37-2820 and 12-37-2850 at the time the vehicle's registration fees are paid.
"(2) Notwithstanding the provisions in Section 12-37-2865(B) and (C), as contained in this SECTION, to the contrary, during calendar year 2019, the first four hundred thousand dollars of fee revenue collected pursuant to Section 12-37-2865 must be retained by the Department of Motor Vehicles to defray programming costs.
"(3) The initial millage required by Section 12-37-2850 must be calculated on or before June 1, 2018.
"M. This SECTION takes effect January 1, 2019, except that the Department of Revenue, in consultation with the Revenue and Fiscal Affairs Office, shall calculate the millage to be used to calculate the road use fee provided in Section 12-37-2850 by July 1, 2018."
2021 Act No. 37, Section 7.B, provides as follows:
"[SECTION 7.]B. This SECTION takes effect on the first day of the fiscal year that begins twenty-four months after the program is fully funded."
The program was fully funded as of July 1, 2022.