DRIVING AT APPROXIMATELY 30MPH PASSING VEHICLE ALLERTED ME OF FIRE AND SMOKE COMING FROM MY REAR. AS I SLOWED DOWN FLAMES AND SMOKE INCREASED. SMOKE FILLED INTERIOR UPON MY EXITING. REAR FIRE CO0NTINUED TO BURN UNTIL FIRE DEPARTMENT. DOOUSED CAR WITH WATER. POLICE REPORT TAKEN. CAR TAKEN TO REPAIR SHOP AND DECLARED TO EXPENSIVE TO REPAIR.