ON THE 4TH OF JULY MY VEHICLE WAS STOPPED IN MY DRIVEWAY WITH THE TRANSMISSION IN PARK. I HAD EXITED THE VEHICLE LEAVING THE DRIVER'S DOOR OPEN WHILE I WALKED UP MY DRIVEWAY TO CLEAR AN OBSTRUCTION IN THE GARAGE DOOR SAFETY EYES. WHEN I GOT TO THE GARAGE DOOR I TURNED BACK AND SAY MY FLEX REVERSING UP THE DRIVEWAY QUICKLY. I HAD PREVIOUSLY BACKED IN AND WAS DRIVING OUT OF THE DRIVEWAY WHEN I NOTICED THE GARAGE DOOR WOULD NOT CLOSE. THE FLEX CONTINUED TO REVERSE UP THE DRIVEWAY (UPHILL) WITH THE DRIVER'S DOOR OPEN. AT THE TOP OF THE DRIVEWAY THE OPEN DRIVER'S DOOR CONTACTED A BASKETBALL POST WITH SUCH FORCE THAT IT BENT THE CONCRETE FILLED POST AND FOLDED THE DRIVER'S DOOR INTO THE LEFT FENDER BEFORE I WAS ABLE TO SLOW AND STOP THE VEHICLE. WHEN I ORIGINALLY EXITED THE FLEX THE TRANSMISSION WAS IN THE PARK POSITION AND THE REAR BACK-UP CAMERA HAD NO DASH DISPLAY. THERE WAS NO WARNING ON THE INSTRUMENT PANEL TO INDICATE THE TRANSMISSION WAS NOT IN PARK. THE VEHICLE WAS OTHERWISE UNATTENDED AT THE TIME. I AM CONCERNED THAT THE VEHICLE WAS ABLE THE SHIFT INTO REVERSE AND THEN REVERSE UPHILL AT A BRISK RATE OF SPEED WHILE UNATTENDED. AT THIS TIME THE FLEX IS SECURED IN MY GARAGE AND HAS NOT BEEN DRIVEN OR INSPECTED IN ANTICIPATION OF REPAIR OR APPRAISAL. I HAVE THE OPPORTUNITY TO HAVE THE PCM AND ACM IMAGED HOWEVER HAVE BEEN INSTRUCTED THAT DATA MAY BE ERASED IF THE VEHICLE IS RUN IN AN ATTEMPT TO IMAGE POTENTIAL DATA. PLEASE ADVISE ASAP YOUR WISHES AS I REQUIRE THE VEHICLE FOR MY