The Mercedes-Benz safety experts have developed the active seat-belt buckle and beltbag with the aid of virtual human models, which provide a clearer picture of what happens to a vehicle's occupants in an accident than crash test dummies. For these digital models simulate not only the human body's outer form, but also its internal structures, such as bones and soft tissue.

"All the crucial biological features of humans – joints, muscles, tendons, ligaments, bones – can only be simulated in very rough terms with dummies," explains Dr Hakan Ipek, expert for virtual human models at Mercedes-Benz. "Some seated positions, such as when a rear passenger is dozing and the belt does not pass over the pelvis in the correct manner, simply cannot be recreated with a dummy," he adds.

With virtual human models, on the other hand, the biomechanical characteristics of the human body are simulated in detail on a computer, enabling examination of the stresses to which the model is exposed in a virtual crash test.