For the purpose of carrying out this chapter, any county legislative body has the right to divide its county into no less than three (3) nor more than eight (8) road districts. For each road district, there shall be elected one (1) road commissioner, so that no more than one (1) road commissioner shall be elected from the same road district; but to divide the county into road districts the road districts shall in no wise interfere with the civil districts of any county, for any purpose whatever, except for convenience in selecting the commissioners for the purpose of giving all parts of any county representation in the construction of roads under this chapter.