ON 2/14/19, I WAS DRIVING ON A CITY STREET IN A STRAIGHT LINE AT APPROXIMATELY 40MPH. THE CAR AHEAD OF ME STOPPED. I STEPPED ON THE BRAKE AND INSTANTLY THE DASHBOARD WARNINGS LIT UP - ADAPTIVE CRUISE CONTROL, COLLISION MITIGATION BRAKING SYSTEM, ROAD DEPARTURE MITIGATION SYSTEM, AND THE BRAKE - AND THE BRAKE DID NOT WORK SO I COULD NOT STOP. I REAR-ENDED THE CAR IN FRONT OF ME DOING SIGNIFICANT DAMAGE TO THE FRONT OF MY CAR. THE WARNINGS WERE STILL VISIBLE AFTER THE CRASH AND I TOOK PICTURES OF THE DASHBOARD AS BEST AS POSSIBLE. THE WARNINGS SAY SOMETHING ABOUT SYSTEM NOT WORKING AND TO SEE A DEALER. THE SAME WARNINGS APPEARED ON 2/13/19 IN THE AFTERNOON BUT DISAPPEARED ON 2/14/19 IN THE MORNING. OTHER WARNINGS OF SAFETY SYSTEMS NOT ACTIVE HAVE APPEARED DUE TO ICE/SLUSH BUT THEN CLEARED WHEN THE SENSORS WERE CLEARED, BUT THESE NEW WARNINGS ARE DIFFERENT. AT LEAST TWICE, MAYBE THREE TIMES IN THE PAST FEW MONTHS, THE CAR WOULD SUDDENLY BRAKE AND SLOW DOWN WITH NOTHING IN THE ROAD OR IN FRONT OF THE CAR. MY BLUETOOTH CONNECTIVITY WORKED FINE FOR FIRST 2-3 MONTHS BUT THEN STOPPED AND I COULDN'T RECONNECT THE PHONE OVER THE PAST TWO MONTHS. IT SEEMS LIKE MORE THAN ONE SYSTEM/ELECTRONICS PROBLEM AND SEEMS LIKE THE WARNINGS APPEARED AT THE SAME TIME AS THE BRAKE NOT WORKING AS IF IT WAS MORE THAN AN ALERT BUT A SYSTEM (SYSTEMS) NO LONGER FUNCTIONING AT ALL. THE BRAKE WORKED AFTER THE ACCIDENT WHEN THE CAR WAS RESTARTED.