ON A FM ROAD, DOING APPROXIMATELY 60 MPH. FRONTAL IMPACT WITH A GUARD RAIL, WENT OVER RAIL, HIT TREE. AIR BAGS DID NOT DEPLOY. DRIVER HIT STEERING WHEEL UPON IMPACT WITH GUARDRAIL, HIT WINDSHIELD WITH HEAD WHEN VEHICLE STRUCK TREE. (NOT WEARING SEAT BELT AT TIME OF IMPACT.) VEHICLE HAS BEEN DECLARED A TOTAL LOSS. WE BELIEVE THE ISSUE IS, THE AIRBAG SENSORS.