DRIVING APPROX. 20 MPH IN CITY TRAFFIC, CAR IN FRONT STOPPED SUDDENLY. I TRIED TO APPLY BRAKES AND THE AUTO-BRAKING SYSTEM ALSO FLASHED ON DASHBOARD TO "BRAKE!" BUT WHEN I TRIED TO, THE BRAKES WERE NOT AS RESPONSIVE AS USUAL. I APPLIED TREMENDOUS PRESSURE ON THE BRAKE PEDAL (SO MUCH SO THAT MY FOOT STILL HURTS OVER A WEEK LATER) AND THE BRAKES DID NOT REACT AS THEY TYPICALLY DO, SO I HIT THE CAR IN FRONT OF ME.