The expected improved performance of a combined restraint system where an airbag supplements the conventional safety belt was not reflected in reduced g-values on the dummy's chest. However, by the distribution of forces over the wider area of the airbag and the corresponding reduction of the pressure exerted by the 3-point belt, improved occupant protection is actually produced. Therefore, a new method to measure the deflection of dummy ribs with strain gauges has been developed. The resulting data indicate a significantly reduced chest deflection when a combined system is used.

Similarly, a concentrated load from a steering wheel in the mouth area at a low HIC value means a higher injury risk compared to a widely distributed load from an airbag at an even higher HIC value. Consequently, an additional facial bone injury criterion based on measurements of the specific loading on the dummy's face would be useful, and an alternative calculation of HIC focusing only on that portion of the head acceleration curve assumed to have a brain-injury potential is necessary