So this table shows that a triad arrangement has more resistance to ground than 2 rods in a line. About it's only purpose, besides wasting material, is when 20' rods are installed and you cannot get 20' between them. Okay, maybe there is a place for them with standard rods and extremely difficult installation (like in rock) but there is no need for triads in the majority of the new construction where you see them specified.
