[With regard to any county which is required to operate on a countywide system of road administration as described in Section 19-2-3, this section shall read as follows:]
One-half (½) of all ad valorem taxes collected by or for a county on property within a municipality (the streets of which are worked at the expense of the municipal treasury, or worked by municipal authority) for road purposes of such county, not including taxes for the purposes of paying bonds issued for road purposes or the interest thereon or for creating a bond and interest fund for retiring the same, shall be paid over to the treasurer of such municipality for said municipality.
Any municipality may contract with its board of supervisors, whereby work may be performed on the streets maintained by said municipality in lieu of the refund of one-half (½) of the road taxes collected under this section, and in such event such agreement shall be spread at large upon the minutes of both the governing authorities of such municipality and the board of supervisors of such county.