In October 1990, the National Highway Traffic Safety Administration (NHTSA) in the United States issued Federal Motor Vehicle Safety Standard 214,^(1)-(3) which specifies the occupant protection required in side impact crashes. This standard prescribes two dummy injury criteria for use in side impact tests—the thoracic trauma index (TTI) and maximum pelvis acceleration. Two major factors that are known to influence dummy injury criteria are the door intrusion velocity and secondary impact point intensity, i.e., the force-displacement characteristic of the door at the point of secondary impact with the dummy. The door intrusion velocity and the secondary impact point intensity are affected by such factors as the construction of the body side, door construction and firmness of the door padding.

This research focused on the maximum pelvis acceleration and an investigation was made of its relationship to the secondary impact point intensity. A force-displacement characteristic factor, η, at the secondary impact point was derived as an index for representing the secondary impact point intensity. The validity of η was confirmed by analyzing experimental data obtained in full scale tests. In addition, a new bench test procedure has been developed for assessing η in tests of door assemblies alone.