[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:]
Each member of the board of supervisors shall inspect every road and bridge in the county under the jurisdiction of the county not later than December 31, 1989, and, thereafter, not less than once each fiscal year. Each member shall file with the clerk of the board a report, under oath, of the condition of the roads and bridges inspected by him with recommendations by him for a four-year plan for construction and major maintenance of such roads and bridges. Based upon such reports, the board of supervisors shall, on or before February 1, 1990, and on or before February 1 of each year thereafter, adopt and spread upon its minutes a four-year plan for the construction and maintenance of county roads and bridges. The plan may be amended at any time by a vote of the majority of the members of the board of supervisors.