The board of county commissioners of any county shall periodically prepare a proposed county construction program of roads on the county road system, setting forth a general description of the roads to be constructed, the location of bridges constituting a part of the program, the approximate total mileage, and the priority of construction.

1.    The board of county commissioners may levy a tax not exceeding a tax rate of ten mills per dollar of the taxable valuation of property in the county for the improvement of county roads and bridges.

2.    When authorized by a majority of the qualified electors voting upon the question at a regular or special election in the county, the county commissioners may levy and collect an additional tax for county road and bridge purposes not exceeding a tax rate of ten mills per dollar of the taxable valuation of property in the county. The levy pursuant to such an election may be discontinued by the board of county commissioners or, upon petition of five percent of the qualified electors of such county, the question of discontinuance of the levy must be submitted to the qualified electors of the county at any regular or special election and, upon a favorable vote to discontinue the levy of a majority of the qualified electors voting, such levy must be discontinued.

Of the proceeds of the tax collected under levy authority under this subsection on account of property situated within any city, by the county treasurer of the county in which the city is located, twenty percent must be turned over by the treasurer to the auditor of the city, in the manner provided in section 11-13-06 to be expended under the direction of the governing body of the city in the improvement of its streets and highways.

3.    When a county requires levy authority for county road and bridge purposes in excess of the limitations under subsections 1 and 2 and the county is authorized by a majority of the qualified electors voting upon the question at a regular or special election in the county, the board of county commissioners may levy and collect an additional tax not exceeding a tax rate of ten mills per dollar of the taxable valuation of property in the county. The levy pursuant to an election under this subsection may be discontinued by the board of county commissioners or, upon petition of five percent of the qualified electors of such county, the question of discontinuance of the levy must be submitted to the qualified electors of the county at any regular or special election and, upon a favorable vote to discontinue the levy of a majority of the qualified electors voting, such levy must be discontinued.

4.    Additional levy authority authorized by electors of a county under this section or section 57-15-06.3 before January 1, 2015, remains in effect under the provisions of law at the time the levy was authorized for the time period authorized by the electors but not exceeding ten taxable years, unless discontinued earlier by the board of county commissioners or the electors of the county. After January 1, 2015, approval or reauthorization by electors of increased levy authority under this section may not be effective for more than ten taxable years.

5.    The county treasurer shall retain and deposit in a fund known as the county road and bridge fund the county share of the tax under this section and any proceeds of this tax totaling less than twenty dollars in a taxable year which is collected on account of property situated within any city. Proceeds of the county share of the tax under this section must be expended in the improvement of highways as provided in this chapter under the direction of the board of county commissioners. The provisions of this section in regard to allocation apply to the proceeds of any tax originally levied for other purposes if appropriated or transferred to the county road and bridge fund or for expenditure for road and bridge purposes.

    Any unobligated balance in the farm to market and federal aid roads fund and county road fund on or after August 1, 2015, must be transferred to the county road and bridge fund, and the farm to market and federal aid roads fund and county road fund must be closed out.