a blow molded formation with energy buffers provides absorption of vehicle occupant cranial impacts . a generally plastic , forced air , expanded formation defines a cavity , the formation walls being of varied geometric shapes having calculated wall thicknesses , each shape having an energy absorbing and resiliency characteristic . the formation of geometric shapes is positioned depending upon the vehicle stiffness characteristics and the degree of impact absorption required . geometric shapes employed may consist of sinusoidal waveforms , a gabled design , or either of the preceding with an internal strengthening rib employed to alter formation impact absorbing characteristics . the formation contains an orifice to ensure that vehicle occupant energy is efficiently absorbed during the concurrent events of formation compaction and air expulsion through the orifice . the blow molded formation may be glued or otherwise suitably fastened to an automobile headliner , door panel , pillar , or other location .