CRUISE CONTROL SET AT 70 ON HIGHWAY, DRY PAVEMENT, DAYLIGHT HOURS AND NO PRECIPITATION OCCURRING. VEHICLE SUDDENLY STARTED DRIFTING TO THE LEFT AND AS I WENT TO CORRECT IT, MY STEERING WHEEL DID NOT RESPOND AS IT SHOULD HAVE AND MY CAR CONTINUED TO GO OFF THE LEFT SIDE OF THE ROAD HITTING THE GUARD RAIL SEVERAL TIMES. ALL THIS HAPPENED INSTANTANEOUSLY AT HIGH SPEED. SIX DAYS LATER I RECEIVED THE BULK MAIL FORM LETTER FROM GM DATED JANUARY 2015 INFORMING ME THAT MY VEHICLE "MAY EXPERIENCE A SUDDEN LOSS OF POWER STEERING THAT COULD OCCUR AT ANY TIME WHILE DRIVING". I CAN ONLY SPECULATE THAT SUCH PRIOR KNOWLEDGE MIGHT HAVE EQUIPPED ME TO HANDLE THE SITUATION WITH ANY SORT OF READINESS, WHICH GM IS ASSUMING IT WOULD DO BY THIS LETTER. THEY NEED TO DO MORE! I AM POSTING HERE BECAUSE GM CUSTOMER SERVICE REP NEVER ASKED ME WHAT HAPPENED AND WHEN I ATTEMPTED TO TELL HER, SHE DID NOT ACCURATELY UNDERSTAND WHAT I WAS SAYING AND DID NOT ACCURATELY OR COMPLETELY TAKE MY STATEMENT. *TR