The Traffic Accident Reconstruction Origin -ARnews-

Re: seat belt injury

Zygmunt M. Gorski (gorski@golden.net)
Fri, 8 Jan 1999 15:57:40 -0500 (EST)

A good way to approach this is to submit a request for data analysis of
a large research study such as the NASS. UMTRI at the Univesity of
Michigan is able to conduct such an analysis if you provide them with
the confines within which you want to conduct your study. I believe
Charles Compton at UMTRI used to be the contact person.

Overall, my impression is that fatality is an outcome arising from injury
while injury is the actual outcome of the force, acceleration or Delta-V.
There are many instances where the outcome "fatality" can occur which
may not match well with the magnitude of the injury. From a simple
example, a laceration at a blood vessel can result in fatality if
treatment is unavailable. But what about age, frailty, body type, manner
of seat-belt use, and so on and so on.... It the end, the Delta-V at
fatality occurs in real life collisions is really a distribution, not
a descrete number.

I recall a Swedish study noted that a seat-belt restrained driver had
died in a 12 mph Delta-V. In other real-life collisions, involving
longer ride-down times, occupants have survived tremendous Delta-Vs that
would seem impossible in a controlled-test, 30 mph barrier impact.

In my experience Delta-Vs in the 20 to 30 mph range can begin to create
"complicated" injuries of the soft-tissues (abdominal organs, lungs,
aeortic tears) if the seat-belt is mis-positioned or worn with slack.
These injuries would be classified as AIS-3 and higher on the
Abbreviated Injury Scale. But don't quote me as I am simply going from
memory. In reality, a well-positioned seat-belt would not expect to
produce such injuries below a 30 mph Delta-V. But in real life everything
depends and nothing is sacred. A frail 75-year-old female is different
than the 21-year-old body-builder. The impact into a farmer's haystack
is different than the impact of a bridge abutment.

Check the STAPP, SAE, AAAM...proceedings. At last resort contact someone
like Murray Dance at Transport Canada, Ottawa. Canada has been living
with manditory seat-belts use since about 1976 and Murray has had to
review a lot of the more sensational or unusual seat-belt cases.

Zygmunt M. Gorski
gorski@golden.net