Abstract
A balanced effort must be brought to bear on each attempt at design improvement and each effort will as a rule entail several of the following; 1- Biomechanics, centering around estimates of human tolerance for specific points of impact against the body. 2- Theoretical simulation of occupant kinematics by the use of mathematical models. 3- Statistical considerations, including severities and frequencies of particular types of injury. 4- Experimental analysis by laboratory or field impact tests. 5- Human factors. 6- Comparison of alternate designs.