MY SON WAS DRIVING NORTH ON I45 FROM HUNTSVILLE, TX TO FORT WORTH, AT APPROXIMATELY 11:30 PM. HE WAS DRVING APPROXIMATELY 70-75 MPH NEAR MM159 WHEN HE HEARD A LOUD THUD NOISE COME FROM UNDER HIS TRUCK. HE IMMEDIATELY OBSERVED FLAMES COMING FROM THE REAR OF THE TRUCK AND IMMEDIATELY PULLED OFF THE ROAD AND STOPPED. THE FLAMES ENGULFED THE REAR OF THE TRUCK AND UNDER THE CAB OF THE TRUCK. HE EXITED THE VEHICLE AND SUSTAINED A BURN TO THE LOWER PORTION OF HIS LEFT LEG. SECONDS AFTER HE EXITED THE VEHICLE, THE ENTIRE TRUCK WAS ENGULFED IN FLAMES. A TEXAS STATE TROOPER WAS PASSING SHORTLY AFTER MY SON EXITED THE VEHICLE AND REQUESTED ASSISTANCE FROM THE FIRE DEPARTMENT AND PARAMEDICS. (PHOTOS TAKEN).