In road districts in counties polling not less than 1,800 votes and not more than 2,999 votes, the board of county commissioners may levy a property tax on property within the road district of not more than 30 cents on each $100 of assessed valuation for the maintenance and repair of roads within the road district. The proceeds of the tax shall be placed in the road district fund of the district in which the tax is levied, and shall be used exclusively for the maintenance and repair of roads within the district.