WE WERE TRAVELING EAST ON HWY 63 GOING HOME. THE LANE DEPARTURE ASSIST CAME ON BUT WE WERE NOT OUT OF LANE. WE KEPT TRAVELING A LITTLE FURTHER AND THE STEERING WAS STIFF. WE WERE TRAVELING ABOUT 53 MPH AND THE CAR ALL OF A SUDDEN JERKED VERY SHARP TO THE RIGHT AND WE WENT OFF THE ROAD HITTING PARKED TRUCK AND FLIPPED IT. THE WHEELS JUST TURNED THE RIGHT AND WOULD NOT LET US TURN THE WHEEL