S.C. Code Ann. § 57-5-1380: Turnpike revenue pledged for payment of bonds.

For the payment of the principal of and interest on all turnpike bonds, there is irrevocably pledged all turnpike revenues derived from the turnpike facility financed by the bonds to the extent and in the manner prescribed by the bond resolution. Any interest earned on turnpike facility account balances must be credited to the turnpike facility account.