DRIVING UP TO INTERSECTION, APPLIED BREAKS NEXT THING AWARE OF WAS THE CAB WAS SMOKEY AND AIRBAG HAD DEPLOYED AND VEHICLE WAS STOPPED AGAINST A TREE IN THE DITCH. NO KNOWLEDGE OF TIRE FAILURE, POTHOLE, OR ANYTHING LEADING TO A DEPLOYMENT OF THE AIRBAG. CONCERN WITH UNNECESSARY DEPLOYMENT OF AIRBAG VERSES STEERING/BREAKING/TIRE PROBLEM. THE AIR BAG KNOCKED ME UNCONSCIOUS AND I WAS UNABLE TO DO ANYTHING TO AVOID THE EXTENSIVE DAMAGE THAT OCCURRED TO THE TRUCK. *NLM