TWO THINGS AT ONCE Put simply, traction can be used for four purposes: decelerating, accelerating, and cornering left and right. Using only one input at a time (throttle, brakes, or steering) creates a cross, not a circle. Filling in the circle requires combining inputs, or doing two things at the same time, for example, braking, or accelerating while cornering. You can ask tires to do two things at once, but they cannot provide maximum grip in two directions at once. The curves connecting the four axes illustrate how traction is shared between braking and cornering forces, and accelerating and cornering forces.