WHILE TRAVELING ON THE DALLAS NORTH TOLLWAY, IT BECAME DIFFICULT TO STEER THE VEHICLE. IT STARTED TO PULL TOWARDS THE LEFT AT FIRST SLIGHTLY, THEN MORE VIOLENTLY CAUSING ME TO CRASH INTO THE CONCRETE MEDIAN THAT SEPARATES THE NORTH AND SOUTHBOUND LANES OF THE HIGHWAY. I SUSTAINED ACCUTE MUSCLE AND LIGAMENT SPRAIN IN MY BACK. THE VEHICLE WAS OPERATING FINE THE PREVIOUS DAY. *AK