(a) In any year in which the General Assembly appropriates by line item, and with reference to this Code section, funds necessary to provide grants to counties to aid in the construction and maintenance of county roads, such grants shall be allotted to each county pro rata according to each county's share of the total number of homesteads in the state for the immediately preceding year. For purposes of this Code section and Code Section 36-17-22, the term "homestead" shall mean and include all that tangible property upon which an ad valorem property tax homestead exemption was claimed and allowed.

(b) In order to provide better fiscal management, the funds provided pursuant to this Code section are intended to be utilized for the relief of ad valorem taxation on tangible property. No county shall be entitled to receive any of the funds provided for in this Code section unless and until a credit against county ad valorem property taxes levied and expended by the county governing authority is granted by the governing authority of the county to each homestead located within the county. Each credit shall equal an amount computed as follows: the amount of the grant allotted, pursuant to this Code section, to the county to aid in the construction and maintenance of county roads, divided by the number of homesteads in the county.

(c) No credit granted pursuant to this Code section shall exceed one-half of the credit recipient's total tax liability for county ad valorem property taxes levied and expended by the county governing authority.

(d) If a surplus remains from the funds allotted to such county by this Code section after complying with this Code section, such remaining funds shall be deemed appropriated and allotted to the county under Code Section 36-17-22.