VEHICLE HAD EXPERIENCED INTERMITTENT STABILITY/TRACTION CONTROL TROUBLE LIGHTS IN COLD WEATHER. WHILE DRIVING IN SUB FREEZING WEATHER ON WET HEAVILY SALTED NEARLY CLEAR (POSSIBLE SLIGHT SLUSH FROM SNOW DUSTING) INTERSTATE ALONG A STRAIGHT SMOOTH SLIGHT UPGRADE STRETCH, THE VEHICLE WITHOUT DIVER ACTION (STEERING, BRAKING, OR ACCELERATION) EXPERIENCED A REAR END SWERVE TO THE RIGHT AND INABILITY TO CONTROL. RESULT WAS LEAVING THE RIGHT SIDE OF THE ROADWAY DOWN A 25-30 FOOT EMBANKMENT (NO GUARDRAIL) AND A VEHICLE ROLL (ONE TIME, ENDING UP WHEELS DOWN, STILL RUNNING). TRAVEL WAS AT OR BELOW THAT OF TRAFFIC. NO OTHER VEHICLES EXPERIENCED DIFFICULTY ON THE SAME STRETCH OF ROAD. IT IS BELIEVED THAT A SUDDEN RANDOM ACTUATION OF THE STABILITY/TRACTION CONTROL SYSTEM INITIATED THE EVENT. THIS APPEARS TO BE A GENERIC ISSUE WITH THE TOYOTA SYSTEM SPANNING SEVERAL MODELS AND YEARS. *TR