a braking system operable independent of driver input , where the braking system includes a primary brake system , a secondary brake system , a primary controller controlling fluid pressure in the primary brake system , and a secondary controller controlling fluid pressure in the secondary brake system independently of the primary controller . there is also an actuator which is part of the primary brake system , where the actuator is controlled by the primary controller . a reservoir is in fluid communication with both the primary brake system and the secondary brake system , to supply fluid to both the primary brake system and the secondary brake system . the primary controller selectively actuates the actuator to control the fluid pressure in the primary brake system independently of driver input , to provide braking capability to a fully autonomous driving vehicle .