The influence of aerodynamics on driving stability and thus on driving safety is due to aerodynamic forces and their consequent moments:
          Lift force and Pitching moment
          Lateral force and Yawing moment
          Rolling moment. [HUC94]
Cars normally experience positive lift. At high speeds, approximately above 150 kmph, the forces of lift significantly change the wheel load. The lift force does not act at the centre of gravity of the wheelbase and hence leads to a pitching moment. Particularly, when the rear axle load reduces considerably, the directional stability worsens and the sensitivity of the steering performance in response to small disturbances increases sharply.
A high stagnation point at the nose leads to an increased lift at the front. A low flow separation at the tail increases the rear lift. The combination of a low stagnation point in front and a high flow separation in the rear leads to a small overall lift and in turn a small pitching moment.