WHILE TURNING LEFT MY CAR WAS STRUCK HEAD ON BY ANOTHER VEHICLE SUDDENLY EMERGING FROM BEHIND A SNOWBANK AND TURNING LEFT FROM THE OPPOSITE DIRECTION. AIR BAGS DEPLOYED. PASSENGER BEHIND THE DRIVER HIT HER HEAD ON THE SEAT IN FRONT OF HER DESPITE HAVING HER SEATBELT FASTENED, AND WAS MILDLY CONCUSSED. THINKING THE PROBLEM WAS WITH THE SEATBELT PRE-TENSIONING SYSTEM. *JS