Looking ahead, Mercedes will equip the cars of their type safety belt can inflate an air bag, helps reduce the effects physical harm to the wearer. This system is called BeltBag, use an air bag to integrate into the second row seat belt worn at the back. When encountering strong shocks, natural gas will be pumped rapidly into the belt and make it swell, reducing injury similar to airbags in the driver.
However, because it uses gas to inflate rather than technical use flares (PyroTechnics) as the common types of air bags so people called them "safety belt can bubble" rather than simply "air bags". When inflated, the contact surface between the strap (chest and abdomen) and the belt will enlarge, help the distribution of forces acting on the body and thereby reduce the intensity of force to avoid harm caused when body moves in the opposite direction with belt clip.
Mercedes had previously performed on the vehicle BeltBag ESF 2009 of his ideas and they do not know what the car will be integrated with it. But it could be the S-Class next generation will be released in 2013. Mercedes is not the first to think about airbags integrated into the safety belt, Ford had to do it on a 2011 Explorer and its getting pretty good responses from many sides.