The products type of G-Vectoring Vehicles will be put into market. The panelists appreciate the handling quality, especially traceability is tremendously good. The authors tried to clarify the fundamental mechanism of handling quality improvement by simple bicycle model and driver model analysis. Especially we focused on the residual-yaw-angular-acceleration when the steering speed is zero. The value was reduced by G-Vectoring Control and it becomes collateral evidence for the handling quality improvement.