I WAS DRIVING ON INTERSTATE 75 NEAR BRADENTON IN FL. 1:00 P.M. PERFECTLY CLEAR & DRY DAY. I WAS HIT FROM BEHIND, SENT MY FORD INTO THE GRASSY MEDIAN, CAR CAME TO A STOP AT A WIRE GUARD RAIL. I DIDN'T HIT ANOTHER VEHICLE. I WAS KNOCKED UNCONSCIOUS, SO I HAVE NO RECALL. THIS HAPPENED NEAR A CONSTRUCTION AREA & ALL I REMEMBER IS TRAFFIC SLOWING, PERHAPS I WAS GOING 45-50 MPH, & IN PROCESS OF SLOWING DOWN. ALTHOUGH THERE WAS EXTENSIVE DAMAGE TO LEFT FRONT & SIDE NO AIRBAGS DEPLOYED. MY HEAD/FACE APPARENTLY HIT THE STEERING WHEEL. THEREFORE SEAT BELT RESTRAINTS DID NOT HOLD ME TIGHT TO THE SEAT. I WAS TAKEN TO E.R. - HAD A CONCUSSION, THEY DID LOTS OF TESTS, KEPT ME OVERNIGHT IN ICU, DISCHARGED THE NEXT DAY. ALSO, LATER I WAS TOLD BY AUTO COLLISION COMPANY & INSURANCE INVESTIGATOR THAT THE DRIVER SEAT WAS DAMAGED & HAD APPARENTLY COME LOOSE. THE VEHICLE WAS TOTALED.