DT: HAD A NEW 2005 TOYOTA SIENNA WITH 3,000 MILES ON THE VEHICLE THAT HAD RUN FLAT TIRES, AND THE BACK RIGHT PASSENGER TIRE THAT WENT FLAT. THEN SMOKED AND REACHED A FLASH POINT AND CAUGHT FIRE. WAS DRIVING ON HIGHWAY AT A SPEED OF ABOUT 60 MPH AND NOTICED A JUMPINESS IN THE VEHICLE. DROVE THIS WAY FOR AN UNKNOWN DISTANCE. PULLED TO SIDE OF THE ROAD, NOTICED A LOT SMOKE COMING FROM THE TIRE AND IMMEDIATELY REMOVED FAMILY FROM VEHICLE. CALLED 911, AND AAA. A PASSERBY WHO WORKED FOR THE FORESTRY DIVISION CALLED FIRE DEPARTMENT AS WELL. TWO PASSERBYS USED 2 FULL FIRE EXTINGUISHERS AND PUT OUT FIRE, FIRE DEPARTMENT CAME AFTER AND WATERED DOWN TIRE AS WELL. TOWED TO A DEALER, DEALER DID NOT KNOW WHY TIRE WENT INTO FLAMES. DEALER DID NOT OFFER NO EXPLANATION. CONTACTED TOYOTA SUGGESTED THAT WHEN THE TIRE WENT FLAT ALONG WITH HOT TEMPERATURES, HOT PAVEMENT, AND GASES WITHIN THE TIRE COULD HAVE COBUSTED AND CAUSED THE FIRE. TOYOTA DID REPLACE THE TIRE. THE TI BRIDGESTONE, BRAND B380 RUN FLATS, UNSURE OF TIRE SIZE AT THIS TIME. *AK