- 1. A severe crash (30mph) results in inertial loading of the head below head injury levels (assuming the occupant does not contact the vehicle interior). If a person is to shake (without impact) a 3-year-old child and cause serious head injuries then he/she has to produce loads more severe than a car hitting a wall at 30mph (30mph velocity stopping in less than 0.1 sec). This is absolutely impossible.
- 2. Even if someone could … During a situation where the torso is held and the head rotates as a result of inertial loading (non-impact), the neck forces exceed the injury tolerance before the head acceleration reached injurious levels. The 30mph crash resulted head accelerations below levels for serious head injury while still producing neck loads approximately double the accepted neck injury tolerance.
crash test data is not available due to the fact that this age is usually tested in the appropriate restraint
configuration using a rear-facing child seat.
Inertial Neck Injuries In Children Involved In Frontal Collisionshttp://www.sae.org/technical/papers/2007-01-1170
Michael Prange – Exponent, Inc.
William Newberry – Exponent, Inc.
Tara Moore – Exponent, Inc.
Daniel Peterson – Exponent, Inc.
Brian Smyth – Exponent, Inc.
Catherine Corrigan – Exponent, Inc.
There is a paucity of data regarding the potential for pediatric cervical spine injury as a result of acceleration of the head with no direct impact during automotive crashes. Sled tests were conducted using a 3-year-old anthropomorphic test device (ATD) to investigate the effect of restraint type and crash severity on the risk of pediatric inertial neck injury. At higher crash severities, the ATD restrained by only the vehicle three-point restraints sustained higher peak neck tension, peak neck extension and flexion moments, neck injury criterion (Nij) values, peak head accelerations, and HIC values compared to using a forward-facing child restraint system (CRS). The injury assessment reference values (IARVs) for peak tension and Nij were exceeded in all 48 and 64 kph delta-V tests using any restraint type. The test at a delta-V of 64 kph using only the vehicle belts as restraints resulted in peak upper neck tension, peak upper neck extension moment, and Nij values two times greater than the corresponding IARV. Only small differences were found in the injury metrics between a CRS installed with and without webbing tension except that head excursion was greater in the installation without webbing tension. These data show that the potential for neck injury exists for children involved in severe frontal crashes and restrained in either a forward-facing CRS or by vehicle belts-only, even in the absence of head contact.
A series of frontal sled tests was performed using a 3-year-old ATD seated in three different restraint configurations: a properly installed CRS, an improperly installed CRS, and using the vehicle belts only (no CRS). ATD injury measurements increased with increased crash severity. The belts only configuration produced the highest neck tensions, neck moments, Nij values, head accelerations, and HIC values. With the exception of head excursions, the amount of vehicle belt webbing tension used to install a CRS did not substantially affect head accelerations and neck loads.