LEFT OUR HOME ABOUT 1045A. PUT VAN INTO "DRIVE" AFTER PULLING OUT OF DRIVEWAY IN REVERSE. UNABLE TO STOP WITH THE BRAKES AT STOP SIGN, APPROX 0.1 MILES FROM START. CAR BEGAN TO ACCELERATE ON IT'S OWN, THROUGH THE STOP SIGN, THROUGH A RIGHT HAND TURN, THROUGH A LEFT HAND TURN. ACCELERATOR PEDAL WAS "STUCK" AND COULD NOT GET IT LOOSE. BRAKES HAD NO EFFECT, INCLUDING ATTEMPTS AT EMERGENCY BRAKE USE. WENT UP A HILL HOPING TO SLOW THE VAN, BUT VAN INCREASED ACCELERATION. TREE WAS HIT WITH CENTER OF FRONT BUMPER. AIR BAGS DID NOT DEPLOY. ENGINE CONTINUED TO "REV" AFTER IMPACT. EXITED VEHICLE. RIGHT FRONT TIRE EXPLODED, SEVERELY DAMAGING RIGHT FRONT QUARTER PANEL AREA/COMPONENTS. *TR