DRIVING ON FREEWAY AT APPROX. 50 MPH AND NOTICE CAR ACCELERATING ON IT'S OWN. ATTEMPT TO PULL OVER BUT NOTICE NOT ABLE TO STOP. PUSHING DOWN ON BRAKE ALL THE WAY AND CAR STILL GOING APPROX. 50 MPH. CALL 911 AND WAS TOLD TO PULL EMERGENCY BRAKE. GET INTO SHOULDER LANE AND PULL BRAKE GRADUALLY AS INSTRUCTED. AFTER DOING SO, CAR SLOWS TO APPROX. 10 MPH. AT THIS POINT SHOULDER LANE TURNS INTO DOWNHILL OFF-RAMP AND CAR GAINS SPEED TO APPROX. 15 MPH. TRAFFIC SIGNAL WITH RED LIGHT AND STOPPED CARS DIRECTLY IN FRONT OF ME SO MAKE DECISION TO TURN CAR INTO A POLE ON SIDEWALK. THIS ULTIMATELY STOPS CAR FROM MOVING. HOWEVER, CAR RPM GAUGE STILL REVVING BETWEEN 2.5 AND 3.5 UNTIL CAR IS TURNED OFF. FILE CLAIM WITH MY INSURANCE, INDEPENDENT INVESTIGATOR CHECKS CAR AND FINDS THAT EVERYTHING IS IN WORKING CONDITION AND CANNOT FIND ANYTHING WRONG WITH CAR TO HAVE CAUSED THE SUDDEN UNINTENDED ACCELERATION AND INABILITY TO STOP WHILE UTILIZING BRAKE PEDAL.