Ok just to clarify some things.
LANE FOLLOWING ASSIST (LFA)The button that is like a steering wheel on the steering wheel is for -Lane Centering- and will automatically turn the steering wheel itself to keep you centered.( it goes by the lines painted on road, so be mindful of exits) basically its like autodrive without speed control, works best with mild curves or interstates, will work ok on regular roads as long as u pay attention too. it turns GREEN if it can tell where the car is in lane, which means its active. it turns white when it doesnt know where it is. which means its off waiting to find where it is. put it between the lines again and it will turn green again. i (dont) think it is speed senstive
LANE KEEPING ASSIST(LKA) button which is by your left knee where the dimmer for dash light is. that will do a beep if on, or will steer you back on road away from lines if active.( think of bouncing you back and forth between lines)
Hope this helps!! Love this car.