The Ferguson system also has one very important safety feature which no other Tractor not using the Ferguson system of control had at the time. This is a safety relief control. If while plowing the implement was to strike a solid object, ie large rock or tree root the hydraulic pressure is released, the weight transfer to the rear wheels is immediately reduced to such an extent that the weight of the tractor is actually supported by the implement. Thus leaving the back wheels to harmlessly spin. This prevents damage to implement and tractor and reducing the risk of rear roll over that a lot of tractors at the time suffered from so badly.