- smoother driving. However, the driver can regulate the automatic mechanism of the gearbox to adapt his driving to the prevailing conditions. : Depending on how he uses the accelerator, he can vary the amount of time he remains in each gear and so regulate the acceleration power of his car (within the limits of the engine's possibilities). In certain cases, if the speed of the vehicle permits it, he can even change down by fully depressing the pedal. In addition, by moving the selector lever, he can limit the automatic mechanism to the first two gears, and in certain exceptional cases, use first gear only.