CAR CAUGHT FIRE WHILE DRIVING ON THE FREEWAY. DRIVER HAD ONLY BEEN DRIVING THE CAR FOR ABOUT 10 TO 15 MINUTES. GOT ON FREEWAY FROM DOWNTOWN HOUSTON AND WAS ON FREEWAY FOR LESS THAN 10 MILES. WITNESS SAID CAR WAS ON FIRE UNDER VEHICLE IN THE REAR OF THE HYBRID VEHICLE. DRIVER PULLED OVER TO FEEDER OF FWY AND CAR WOULD NOT GO INTO PARK SO HE TURNED VEHICLE OFF AND EXITED VEHICLE. DRIVER SAW CAR WAS ON FIRE AND RAN TO SAFETY.