A reasonable landing-determination state machine needs to satisfy multiple conditions simultaneously: the distance between the car's lowest point and the ground is below a threshold, the vertical speed is downward or near zero, and the previous frame was in an airborne state, only then triggering a landing event and switching to the grounded state, while a brief tolerance of frames is needed to avoid jitter; using only "landing counts when position intersects the ground" causes a false determination on the first frame when initially resting on the ground.