COMPLETETED A TURN FROM OFF RAMP AND DRIVING STRAIGHT WITH A SPEED OF APPROXIMATELY 35 MILES PER HOUR WHEN VEHICLE LOST STEERING CONTROL AND BRAKING POWER. INPUTS TO THE STEERING AND BRAKING HAD NO EFFECT ON CHANGING VEHICLE COURSE AND/OR SPEED. THE VEHICLE SUBSEQUENTLY IMPACTED A GUARD RAIL AND WAS THEN HIT BY A SEMI TRUCK. NONE OF THE AIR BAGS IN THE VEHICLE DEPLOYED. ROAD CONDITIONS WERE DRY AND THE ACCIDENT OCCURED DURING THE AFTERNOON. INJUIRES TO MYSELF INCLUDED A 2 INCH LACERATION TO THE TOP OF MY HEAD TREATED WITH STAPLES, A BROKEN LEFT CLAVICLE, FRACTURED LEFT RIBS, AND FACIAL BRUISING. I WAS TRAPPED IN THE VEHICLE BECAUSE BOTH DOORS COULD NOT BE OPENED BECAUSE THEY WERE JAMMED BY IMPACT FORCES. I HAD JAGUAR'S MAIN CUSTOMER SERVICE CONTACTED REQUESTING AN ENGINEERNG INVESTIGATION BUT WAS TOLD THAT IT IS NOT SUPPORTED AND WAS DEFERRED TO MY INSURANCE COMPANY. *NM