I WAS DRIVING THE LEXUS RX400H WITHIN THE CITY AND TRIED TO BRAKE SUDDENLY TO AVOID A FAILED CAR IN MY LANE. I PUSHED REALLY HARD ON THE BRAKE PEDAL AND CONTINUED TO STEP HARD ON THE BRAKE. THERE WAS NO BRAKING ACTION WHATSOEVER. IT APPEARED AS IF PRESSING VERY HARD ON THE BRAKE JUST DISABLED THE BRAKE. THE CAR CONTINUED TO DRIVE LIKE IT WAS ON A CRUISE CONTROL AND THE INCIDENT RESULTED IN REAR-ENDING THE CAR IN FRONT. *TR