WHILE SLOWLY PULLING INTO PARKING SPACE IN THE PARKING LOT OF THE LOCAL POST OFFICE, WITH FOOT ON BRAKE PEDAL CAR QUICKLY ACCELERATED FORWARD WITH ENGINE REAVING. CAR SHOT FORWARD GOING OVER CONCRETE CAR STOPS TOWARD A CREEK AND SMASHED INTO A STAND OF TREES. DRIVER AIRBAGS DEPLOYED. COMPLETE FRONT OF VEHICLE INCLUDING HOOD AND WINDSHIELD WERE SMASHED AND DRIVEN INTO ENGINE COMPARTMENT. I BELIEVE THIS IS A CASE OF UNINTENDED ACCELERATION CAUSED BY THE VEHICLE MALFUNCTIONING. THERE HAVE BEEN MULTIPLE DOCUMENTED COMPLAINTS OF THIS HAPPENING IN LEXUS RX 350 VEHICLES. THE FLOOR MAT WAS SECURELY IN PLACE AND HAD NOT MOVED AND THE DRIVER INSISTS HER FOOT WAS ON THE BRAKE PETAL AT ALL TIMES. THERE WERE NO OBSTRUCTIONS IN OR AROUND THE ACCELERATOR PETAL OR THE BRAKE. PARAMEDICS WERE CALLED TO SCENE AND A POLICE REPORT WAS FILED.