Benefits of a 3+2 Point Belt System and an Inboard Torso Side Support in Frontal, Far-Side and Rollover Crashes
Published May 19, 2003 by National Highway Traffic Safety Administration in United States
3-point-belted occupants are still being injured in numerous crashes. In frontal collisions this is partly explained by the range of hard tissue tolerance amongst car occupants. In side collisions occupants on the far side of the intrusion are mainly restrained by the lap part of the 3-point belt, with an associated high risk of sustaining a severe head injury. During a rollover crash the 3-point belt cannot fully prevent harmful head impacts.
In this study an additional 2-point belt (single-handed optional operation) is combined with an inboard torso side support. The idea is simply to distribute the belt load on more anatomical structures (bones) as well as constituting a noninjurious inboard and upward restraint. The inboard side support prevents a direct loading by the 2-point belt to the cervical spine in far-side collisions. It also supports the torso when the 2-point belt is not buckled.
To prove if this design measure is advantageous, frontal, far side and rollover tests were performed. Current standard crash test dummies lack appropriate biofidelity when assessing sophisticated enhancements of standard safety restraints. Therefore the Thor dummy with a set of modifications from the BioSID was used in the tests.
The results showed a considerable reduction of chest deflection in the frontal crash tests, head horizontal motion in the far side tests and head upward motion in the rollover tests. To conclude, an additional 2-point belt, in conjunction with, a 3-point belt and inboard torso side support offer a considerably increased protection in various crash situations without any negative consequences.