THIS MORNING WHILE DRIVING AT 55 MPH ON THE HIGHWAY OUR 2009 COROLLA SEEMED TO JERK ITSELF OUT OF THE MIDDLE OF 5 LANES OF TRAFFIC, STARTED SPINNING, HIT THE GUARD RAIL WITH THE RIGHT REAR TAIL SECTION. THE CAR ESSENTIALLY BOUNCED OFF THE RAIL, CONTINUED TO SPIN ACROSS THE LANES OF TRAFFIC AND BACK, COMING TO A REST BACK ON THE SAME SIDE I HIT THE GUARD RAIL. I WAS EXTREMELY LUCKY THAT NO OTHER CARS MANAGED TO BE INVOLVED IN THIS ACCIDENT. FROM THE MINUTE THE CAR FIRST JERKED OUT OF CONTROL UNTIL IT CAME TO A REST I COULD NOT GAIN ANY CONTROL OVER THE STEERING OR MOVEMENT OF THE CAR. THE CAR HAS DONE THIS TO A LESSER DEGREE ON A FEW OCCASIONS OVER THE PAST FEW MONTHS (CAR WAS PURCHASED USED, FROM A DEALER, 3/13/2010) WHICH WE THOUGHT MIGHT BE DUE TO HYDROPLANING (WE'RE IN SEATTLE WHERE THE ROADS ARE OFTEN WET BUT WE'VE DRIVEN HERE FOR 35 YEARS WITH NOTHING LIKE THIS FEELING IN ANY OTHER CAR) OR A NEED FOR NEW TIRES BUT THIS WAS CLEARLY NOT THE ONLY ISSUE. ON THOSE OCCASIONS IT ALSO FELT LIKE THE CAR WAS SUDDENLY FLOATING AND THE STEERING JERKED IT TO THE LEFT (BUT I WAS NOT GOING THROUGH A DEEP PUDDLE/HYDROPLANING). IT WAS MOMENTARY BUT ENOUGH TO SCARE ME AND MAKE ME WONDER WHAT HAD JUST HAPPENED. IT WAS RAINING THIS MORNING AT THE TIME OF THE ACCIDENT BUT SOMETHING ELSE CAUSED THE CAR TO JERK ITSELF OUT OF THE LANE AND LOSE CONTROL OF THE STEERING. IT IS CURRENTLY IN THE BODY SHOP AWAITING AN ESTIMATE FOR REPAIR. THE TOYOTA DEALER DIDN'T WANT TO LOOK AT IT DESPITE M