ON DECEMBER 12, 2017 AT ABOUT 4:30 PM, THE COLLISION MITIGATION BRAKING SYSTEM FAILED AND PUT MY CAR INTO A PANIC STOP WHEN I WAS NOT ABOUT TO HAVE A COLLISION WITH THE CAR IN FRONT OF ME. I WAS DRIVING EAST ALONG A 4 LANE UNDIVIDED HIGHWAY IN THE RIGHT LANE (SLOW LANE) AT ABOUT 45 MILES PER HOUR APPROACHING A TRAFFIC SIGNAL THAT WAS GREEN. THERE WAS A CAR AHEAD OF ME IN THE SLOW LANE AT THE SIGNAL, SLOWED DOWN TO MAKE A RIGHT HAND TURN. I WAS 5 OR 6 CAR LENGTHS BEHIND THIS CAR AND IN NO DANGER OF COLLIDING WITH HIM. WITHOUT ANY WARNING, MY CAR APPLIED THE BRAKES IN A FULL PANIC STOP. FORTUNATELY THERE WAS NO VEHICLE BEHIND ME. THERE WAS NO COLLISION WITH ANY OTHER VEHICLES, BUT MY RIGHT HIP AND LOWER RIGHT BACK WERE SORE FOR SEVERAL WEEKS. I REPORTED THE INCIDENT TO MY INSURANCE COMPANY AND TO THE DEALER THAT SOLD ME THE CAR. ON THE DEALER'S SUGGESTION, I SET THE FORWARD COLLISION WARNING DISTANCE TO "SHORT"; IT HAD BEEN SET AT "NORMAL", THE FACTORY SETTING. MOST DAYS I MANUALLY TURN THE COLLISION MITIGATION BRAKING SYSTEM OFF BEFORE I DRIVE, BUT ON THE DAYS I HAVE FORGOTTEN, THE PROBLEM HAS NOT RE-OCCURRED WITH THE FORWARD COLLISION WARNING DISTANCE SET TO "SHORT". I BELIEVE THAT IF THERE WAS A VEHICLE BEHIND ME WHEN THE PROBLEM HAPPENED, HE MAY HAVE COLLIDED WITH THE BACK OF MY CAR AND CAUSED ME FURTHER INJURY. I THOUGHT FOR THE SAFETY OF OTHERS, I SHOULD REPORT THIS PROBLEM TO YOU.