TRAFFIC STOPPED ABRUPTLY AND MY CAR (SUBARU OUTBACK) CAME TO A STOP. I WAS REAR-ENDED BY A SEMI (SPEED UNKNOWN BUT DID SIGNIFICANT DAMAGE TO MY VEHICLE) THAT PUSHED ME INTO THE VEHICLE IN FRONT OF ME. THE VEHICLE IN FRONT OF ME WAS THEN PUSHED INTO ANOTHER VEHICLE. THE VEHICLE DIRECTLY IN FRONT OF ME (FORD FREE STAR)HAD ITS AIR BAG DEPLOY. MY AIR BAG DID NOT DEPLOY AND MY HEAD ENDED UP HITTING THE STEERING WHEEL. I WAS DIAGNOSED WITH A CONCUSSION. I AM WONDERING IF MY AIR BAG SHOULD HAVE DEPLOYED IN THIS TYPE OF SITUATION? *TR