Head air bags are also called side-curtain airbags, collision when covering the Windows, to protect passengers ' effects.
When main for side-impact head air bags protects passengers in the head. B-pillar side, window glass, side support, seat belt buckle may even become killers in a car accident. Head air bags will these members and separated.
Head air bags installed in the roof curved steel beams, usually before and after running through, controlled by a lateral acceleration sensor in the body. When acceleration is greater than normal, and reaches dangerous values will control initiation. For side collision, overturn and other serious accidents have a very good personal protection functions.