WHEN APPROACHING STOP SIGN, AT INTERSECTION, VEHICLE ACCELERATED WHEN BRAKES WERE APPLIED, CAUSING A COLLISION WITH THE CAR IN FRONT OF MINE. THE BRAKE PEDAL WAS DEPRESSED ALL THE WAY TO THE FLOOR, AND THE ENGINE ROARED AS IF ACCELERATING. WE HAVE HAD ONE OTHER SIMILAR INCIDENT IN WHICH THE VEHICLE ACCELERATED WHILE BRAKING. DEALER EXPLAINED THAT DRIVER HAD FOOT ON BRAKE AND ACCELERATOR AT SAME TIME. IN SECOND INCIDENT, I AM SURE THAT I HAD MY FOOT ONLY ON THE BRAKE. DEALER EXAMINED VEHICLE AFTER EACH INCIDENT AND COULD FIND NOTHING WRONG.