side impact - Insurance Institute for Highway Safety

W en a car
gets struck very
ha d 'n he si e, ike
thi one did, the result can
be just as deadly as it looks,
early 10 000 people died in side impacts on U. . roads last year, and the prolr
lem isn t just here. bout 6500 people die annually in side impacts in Europe so
ffjcials 00 both ides of the tlantic are addressing this problem.
The U.. side impact protection standard
and the one scheduled to take effect in urope
p cify a test with a moving barrier intended
to simulate a car-to-car crash. Both specify
era h forces that aren't to be exceeded, as
measured on instrumented dummies.
Then the differenc begin.
The m ving barrier are diUerent. The dummi are dj(ferent. The criteria used to m aure the risk of injury are different The up hot
is that U.. and European safety tandards
could lead to different designs for side impact
protection in orne cars.
This doesn't make sense. Human bodies are
the same, so car designs intended to protect
them in the arne type of impact ought to be
the same too. This special Status Report focuses on side impact protection especially the differences between . and European approaches to protecting people.
U. S. and European
Approaches to Protecting
People in Side Impacts Reflect
More Differences than Agreement
Both U.S. and European dynamic
side Impact requirements
erg tell us they have different door designs
- or they will have soon - for cars thai
are intended to reduce
are essentially the same otherwise, de·
injury risk when cars
pending on whether they must meet side
impact test requirements in the United
States or Europe. But only one of these
designs can be optimal lor human beings.
DUfereoces In Test Procedures: Both
the U.s. and European tests mimic a car·
to-car side impact. The struck car is stationary. The striking one is represented by
a deformable barrier that moves. But then
the differences begin, and there are many.
The European barrier moves perpe.!l-"
dicular to the struck car at 31 mph. The
U.s. barrier travels at 33.5 mph, but all
four of its wheels are turned sideways 50
that it moves at an angle to the stJUd: car.
This is intended to simulate an intersection crash in which the struck car is going
15 mph and the striking car goes 30 mph.
Barrier Differences: In tbe United
States. the distance bet-.-een the ground
and the barrier's to.-er edge ~ II inches
are struck In the side
by other vehicles, typically at intersections. The
U. S. standard was phased In
beginning in 1994 and applies
10 all 1997 cars. AEuropean
Union directive will apply 10
new designs introduced after
OCtober 1998 and to all new
passenger vehicles by 2003.
But these two standards
Men't the same. Test requirements differ, and some autcr
makers say they may have to
implement different countermeasures to protect people in the
same type of crash (see "Same Car.
Same Side Impact Protection.· p.6).
For example, Institute President
Brian 01~eill explains. "some carmak·
M
(279 mm) compared with 12 inches (300 mm) in Europe. Alower barrier
tends to strike relatively stiff structures such as the door sill, whereas a
higher one strikes the softer central section of the door. This means that,
in general, the less the ground clearance, the less stringent the test.
On the other hand, the U.S. barrier Is heavier than Europe's and, all
other things being equal, heavier barriers make for tougher tests. Another difference is that the U.S. side impact barrier has a stiff, narrow
piece across its front representing a bumper. The European barrier has
a smooth face.
Wider and Uniformly stiffer than the European barrier, the U.s. one
-doesn't represent a European car very well: Adrian Hobbs of Eng.
land's Transport Research Laboratory points out ·Contrary to what
most people would expect, this stiffness makes it rather more benign
than the European barrier: Hobbs contends the U.s. barrier is so stiff it
can be fended off by reinforcing a car's Aand Bpillars. Merely strengthening these wouldn't improve crashworthiness, according to Hobbs,
who notes that real cars aren't uniformly stiff the way the U.S. barrier is.
The European barrier, Hobbs says, is more demanding even though
it's less stiff. It crushes where it strikes the door pillars while the rest of
it continues through the gap between the pillars.
How the side of a car is pushed in is important, Hobbs continues.
Loading should be spread over an occupant's whole body, not concentrated. He claims the U.s. barrier seems to "help control (delonnationl
in a desirable way, whereas cars don't, regrettably .... 1would be quite
worried about the {U.s.) barrier. In fact, it's probably the thing I worry
about more than any other aspect of the test. w
Other researchers come to dillerent conclusions. Transport Canada
has chosen the U.s. barrier, although researchers at this organization
still are studying some aspects of side impact testing (see "Taking Cues
from U.S. and Europe," p.IO). According to Dainius Dalmotas and others
at Transport Canada who compared the two barriers, ~the U.S. version
was found to produce vehicle deformation patterns and dummy responses which were more consistent with those observed in vehicle-t<>vehicle tests.~
Oynamlc and/or Static Tests: The U.s. side impact protection stan.
dard includes static as well as dynamic test requirements, and the static
ones came rust ears have to ·resist a piston pressing a rigid steel cylinder inward against the door: Reinforcing side doors with metal beams
- the usual method of meeting this requirement- has proven effedive
in single-vehicle crashes, according to federal officials.
In contrast, the European directive doesn't include static requirements at all. ~1I stiff or massive items in the door impact against the oc·
cupant, they could cause more serious injury than the door itself,M
Hobbs says. ~II, like some door beams, they concentrate loads upon a
small area of the body, this is potentially more dangerous than if the
loads are spread more evenly:
Differences Among Test Dummies: The rationale for the side im·
pact rules in both the United Stales and Europe is to reduce the risk of
thoracic and peMc injuries including rib fractures and ((OOt'd on pA)
U.s.
lIldelllli*lllllldanl_
~ lest IpedlItd In ooIlber the
. .cI
1D
iIlJ"'"
Ilructurel
BoIh .....
lll__lawllllllll_.
fiiIoIde
- !IIporIIDI1Jecause
Iii't I
..... Ill""" tIte
PIn.·It.odt. mdudeI a perforllddn!u lIIJarIeIlrom Ibe
lIiIlIItor 1IlIIfII:eI, but I1IdI con-
. . . occur cIurtnc the campiI-
'lll\lle QllIed SIll.., _injuries
......... _by.sepa~'" be
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by
... 1Or1lJe
aad. -..d, tubular head
"'1Il1tbd
.....,...... tIte window (see
$aIirui """'" \Ill3l, No.4, May 4, 1996). The
_ .....ahOUId pml!II1lu11 or partJaI ejection. IIIIW told the Natloaal HIghw.y Traffic
,IIW!!lIl._1haI this cIeIliJ1. sIaIed lor
J99711M1de1J, may not be deployable
............... 1haI cauId be .......... to
U.s. bead protecUoD rule. ADd al...... lbe IIIW.,...,. oller are- head
,......."'...,
mIflhl DOl_ail
...... , t 1pOCI1Bl '" tIIe.- coverlDg
_1iIIpodJ wttb upper_lnIerlors.
SuppolliJIB BMW'. request lor .lterDaU.e
.................. tIte-Uflled thelederal
IlIIIICI'ID"pInl spedaf _ 1 0 'lllems
lbal oIkr beooiItI outside !he scope of existing
llaDdanIaaad to. . - some InItrim acetllIlIIlOdaIIm Ii crash dopIoyabIe SjSlemI desIf1ed to
_
_
meet.
_thIl __
litlte_..-_
Side aldlop d lip EI specollcally to prUect
tile _ .. beIDll dewIoped by _ automat..lid .............
4 Status Repo~ Vol. 31, No. ~ Sept.
2~
1996
(cont'd from p.3)
soft tissue injuries to
the heart, lungs, and other organs. The Eu-
ropean directive also includes abdominal
injury criteria and evaluates head injury
risk if head contact occurs (see ~Neither
Standard Gives Head Protection the Attention It Deserves,~ p.3).
Belted, instrumented dummies are used
to assess injury potential in both U.S. and
European tests, but there's disagreement
about exactly what to measure to assess
particular injury risks. Plus, the side im·
pact dummies used in the two tests mimic
human responses differently.
A key question in developing these
dummies has been whether acceleration of
the spine and ribs or compression of the
rib cage is the key parameter in measuring
injury likelihood. or whether both are important. Acceleration is the rate of velocity
change, and measuring it indicates the
forces inflicted on the body during the
crash. Compression refers to the extent
the body is deformed by the impact.
The first side impact dummy, SID, measures acceleration only. Later generations
01 dummies, EuraSlO and SioSIO, measure
acceleration plus compression. And unlike
SID, they also can measure the likelihood
of neck and abdominal injury.
Developed by the National Highway
Traffic Safety Administration (NHTSA), SID
is used in U.s. testing. EuraSlO, developed
by the European Experimental Vehicles
Committee, is used in Europe. BioSID is
based on a General Motors design.
The acceleration-based injury criterion
used with SID is the thoracic trauma index
(dummy) or ITI(d), According to NHTSA,
TIl is a formula that can be used to predict the probability 01 injury. It's the average of the peak acceleration measured on
the lower spine and the greater of the
peak acceleration values of the upper and
lower ribs of the lest dummy.
Acompression-based injury criterion
used with EuroSJO and BioSIO is the viscous criterion, or V*C, which accounts for
both the extent and rate of chest compression. To calculate V*C, it's necessary to
measure rib deflection. EuraSlD and BiaSlD
are equipped to measure this, but SID isn't.
V*C proponents argue ils superiority, compared with m(d) or other accelerationbased injury criteria, which EuroSIO and
BioSIO also measure.
For example, an auto manufacturers'
trade association has told NHTSA thaI measuring acceleration of rigid dummy spine
or ribs doesn't reliably predict injury to
viscous chest organs. The potential for
such injury can depend on the extent and
rate of compression, both 01 which V*C
takes into account. Although TIl indicates
maximum force - the agent that causes
compression - it doesn't consider how
fast the force is applied or how much compression results.
NHTSA defends TIl, noting it was deve~
oped with 10 years of cadaver testing in
which rib and spine acceleration was compared with the severity of thoracic injury
during impacts. uThe occurrence of injuries to the hard thorax, which includes
both the ribs and the internal organs protected by the ribs, is strongly related to the
average of the peak lateral acceleration experienced by the struck side rib cage and
lower thoracic spine,' NHTSA says.
The agency claims that ~as long as ...
TII(d) ... can discriminate risk of thoracic
injury, the precise injury mechanism (acceleration, compression, some combination of forces, etc.) is not critical .... Since
accelerometers on the ribs and spine are
located close to the viscous organs within
the chest, they measure parameters that
may cause viscous organ injuries."
And while there are no abdominal injury criteria in the standard, NHTSA says
the lower rib and spine accelerometers
are close to where abdominal organs such
as the liver, spleen, and kidneys would be.
Critics aren't convinced. ~The absence
of any performance criterion addressing
abdominal injury clearly represents a major deficiency in the current requirements'
of the U.S. standard, Transport Canada's
Dalmotas concludes. The problem could
be remedied, he points out, by replacing
SID with either EuroSID or BioSJD.
Which Dummy?
"It doesn't make sense
to eoaluate side impact
protection using an outol-date and inadequate
dummy, especially
when better dummies
are auailable. "
Brian O'Neill, President,
Insurance Inslirure for
Highway Safety
Which Barrier?
"I would be quite worried
about the [US] borrier.
In fact, it's probobly the
thing I worry about more
than any other aspect, "
Adrian Hobbs,
Transpol1 Research
Laboratory, Eng/and
"The US, {barrier] was
found to produce vehicle
deformation patterns and
dummy respanses which
were more consistent with
those obseroed in vehicleto-vehicle tesa. "
Dalnius Dalmo/OS,
T_C<moda
Status Report,
SID-lIs and the
Quest for aDummy
To Use Worldwide
'If We Could Get to One Test
Device that Truly Is Oose to a
Human Being, That Would Be a
Huge Advantage Everywhere'
What with ID. Eor ID, and Bi ID. rt
might seem like the last thing th arid
needs is another ide impact dumm . But
it's exactly hat's needed, according to
the Occupant afety Research Partner hip
created by a research consortium of U..
automakers. The partnership says it s
time to replace the three rival dummies
(see "Differences Among Test Dummies n
p.3) with a new one everyone agrees on.
"Individuals around the world are aU
basically he arne biomechanicall so
having differen dummies in dillerent markets is not warranted from a biomechanical standpoint," the partnership told the
1996 conJerence on the Enhanced ale
of Vehicles. The goal i one dummy pecified in worldwide regulation."
Many international experts share this
viewpoint. Yet agreement on a worldwide
dummy may be a long way off.
tars ( s) represent sensors. The
red represent abdominal sensors.
SID was the first side impact dummy, developed in the fate 1970$ by
the National Highway TraHic Safety
AdminisfTafion. Critics of this test
dummy charge that the absence of
sensors in lis abdominal region underscores its inktiority to the lIDo
newer side impact dummieJ, Em&
SID and BioSlD.
SID-lIs i the dummy the partnership
proposes to "become an international corr
sensus choice .' . lirst in a f.amil of technologicall advanced ide impact dummies.
econd generation (II) mall ( )
ide impact dumm Io-ns corr pond
to a 5th percentile adult female.
Besides serving as a prototyp for an
international test device, this dummy is
designed to help evaluate the effect on
smaller occupants 01 various countermeasures including side airbags. The three
side impact dummies now In u e - SID,
EuroSlD, and Bio ID - correspond to 50Lh
percentile males. The partnership hopes a
midsize adul male SlD-IIs would follow alter orld'de evaluation and modification" of the th percentile female.
31,
I.
0.
Confiden e in ID-U as a n ensllS
choic com partly becau e It i n't perilied in any regulation. But thi tatus
makes it a p or choice lor international
recognition, according to Jac Wi mans 01
TNO Road-VI hides Research Institute in
the etherlands, which h Iped d velop
Euro ro. He otes that both 10 and EuJOID appear i regulations. and Bi lD has
been exten ively tudied. But ID-n as
"de eJoped without European inpuL and
deviates fr all three.
"IL' much more difficult I th' ,to e
such a dum y accepted than It would be
to sit d wn iLh the Japanese, uropean
and Americans and define whaL is ood
and not good about Euro ID and lD .... It
would be mu 'h easier to intr duce uch a
modified du my In a regulation than to
just start Iro scratch," ays Wismans.
tarting from cratrn i what oger
Daniel th partnership s pr j man er
for ID-IJs pr poses if this dummy i n t acceptabl" ha a good t t d . ,bu
we auld be willing to complet I tart
over if that' hat the 'orld communi
want ," he a .
Daniel a knowledges om of th criticisms, an wering the complaint hal lOris was designed without worldwid input
by explaining this was believed to b the
quickest way to provide a pie e f hardware experts worldwide could valuate."
Although lh JD.I1s prototype
designed a cor ing to the EngU h tern of
measurement , the first produ . n dummy, available in mid-l99 will be enti 1.
metric. And rhile ome sa lD-1Is' imply a mailer ersion of Bio m, Dani I and
his colleagu claim ~all design asp t
were con idered from the thre mid ize
male sid impact dummies now in lise.
IIThere are a lot of individuals and perhaps corp rations and perhap ven governmenL entities that are not happ with
SID or uro 10, Daniel point out. Th
whole object i to act as a catal 1. w
could et to one test device tha
i
close to a human being that would be a
huge advantag everywhere."
ft
Same Car Could Be Designed Two Ways to
Meet Two Different Side Impact Standards
Car That Looks the Same Could Differ in Crash Protection
Depending on Whether It's lor Sale in U.S. or Europe
Both the U.S. and the European side
impact protection standards are based on
performance. That is, they allow auto
manufacturers to modify their vehjcles
any way they want a long a they meet
applicable injury criteria. This means an
automaker can modify a car differently to
meet either the U.S. standard or the one in
the European Union.
Ford, General Motors, and Chrysler say
design dillerences may become necessary.
"Lack of harmonization" between the U..
and European standards is necessitating
llmassive effort tbat is not productive:
Guy Nusholtz of Chrysler points out.
Modifications could include structural
changes, added door padding, or a combination. ~Paddlng is only a complement to
structural improvements and bas only lim-
ited effect on its own," Adrian Hobbs says
in reference to the European directive.
Hobbs is affiliated with England's Transport Research Laboratory.
According to the National Highway
Traffic Safety Administration (NHTSA)
llStruc;tural improvements alone did not
necessarily result in significant reductions
in thoracic acceleration." The agency says a
better approach is "to provide 'equivalent
padding' (either actual padding or modified, energy-absorbing sheet-metal structure) as necessary in the door area. This
should be more cost-effective than making
structural changes" to reduce injurjes to
the thorax and pelvis.
Even manufacturer who u e padding
10 meet both standards may not be able to
use the same type of padding. "Generally,
the thorax padding effective to meet the
U.S. standard is too stiff for EuroSID and
tends to increase its chest deflection,
Toyota sMasatake Shiratori told Status Report. Such padding isn't used in the European versions of the Celica and Paseo.
In. comments on the U.S. side impact
rule, several automakers have questioned
the overall effectiveness of the padding
that achieves acceptable TII(d) values in
compliance tests. Both General Motors
and Ford claim ~the use of TIl(d), coupled
with ... the excessive stiffness and excessive mass of the SID chest, could lead to
the use of interior padding that is overly
stiff and could actually degrade occupant
safety, particularly that of the elderly.
(The U. .side impact standard relies on
the injury criterion mCd) while the European directive uses compression-based criteria including V*C. For an explanation of
these and discussion of rD versus Euroill, see "Differences Among Test Dummies p.3.)
Aconsideration i the effect o~ certain
types of padding on elderly occupants.
This is important because research indicates that improvements should focus on
elderly people who are more likely to be
involved in fatal side impacts and are
more vulnerable to serious injury.
"You have to be very careful. We don't
design our vehicles blindly" to the U.S.
standard, Robert Hultman of Ford explains.
We ... make sure that we don't put overly
stiff padding in just because the dummy
says you're going to pass."
Some automakers question whether
the padding that reduces TTl in crash
tests would have any benefit in actual collisions. BMW has told NHTSA that TTis
were so sensitive to dampi.ng that they
could be "reduced without achieving a corresponding increase in real-world safety."
According to Nissan, the "padding hardness" that's required "to minimize TIlCd)
values on the one hand and minimize V*C
and rib deflection values on the other did
not match."
While not foreclosing the possibility
that the U.S. tandard auld be improved,
HT Ais confident it's effective. The
agency's RoH Eppinger, who was instrumental in developing TIl, says NHTSA researchers have studied the performance
in actual crashes of cars that meet U.S.
side impact requirements. lIes a very small
handful of cases. But at this point we have
no evidence that cars designed to TIl, using SID and our crash conditions, produce
a vehicle that's not safe."
Led by Dainius Dalmotas of Transport
Canada, Canadian researchers have analyzed the U.S. test and take a different view
(see ~Taktng Cues from U.S. and Europe"
p.lO). "All of the [Canadian] tests, even
those which produced exceptionally low
TTl values, exceeded biomechanical injury thresholds" for abdominal injuries. In
other word t cars designed to produce
good TIls may not be as safe as possible.
The latest developments are side airbags in addition to frontal ones. These
might make it easier for automakers to
meet U.. and European requirements using one design.
"We think we could ... although we're
not sure. But you do have to make the
airbag aggressive," Nusholtz of Chrysler
points out.
Ford's Hultman says he generally agrees
with this. "We do believe that side airbags
may enable us to achieve one design faT
both Europe and the United States, and
right now we're doing research and development on a combination head/chest bag
toward this goal. However, it might be necessary to have slightly different rates of
inflation and/or airbag internal pressure
to satisfy both requirements [U.S. and Europe], which again would get you two dif·
ferent designs. But they should be a little
easier to control if you can do it wjth a
side airbag."
Volvo, the first manufacturer to offer
side ail'bags, says it simultaneously meets
both standards with interior door
padding together with other measures,
adding that the airbags "make the cars
even safer.» However, the potential design
conflicts produced by the two standards
are thought to be more of a problem for
somewhat smaller cars than Volvo sells In
the United tates.
8 Slatus Report, Vol. 31,No. 8, Sept. 28, 1996
Should Side Impact
Tests Be Added to
NeAP's Fronta Ones?
The lederal government not only sets
compliance test requirements for Dew cars
but also conducts crash tests to supply
consumers with safety information and to
prompt automakers to improve occupant
protection. So far, these tests under the
New Car Assessment Program (NCAP) include frontal impacts only. Now that all new
cars have to meet dynamic side impact requirements, it might be the right time to expand NCAP to indude side tests, too.
The National Highway Traffic Safety Administration thinks so. NCAP has been successful (see Status Reporl; VOl. 30, No.1, Jan.
14, 1995), so it may be assumed that side
impact information would be useful, too.
The side tests the agency is proposing
would be run at a higher speed than compliance tests - a closing speed of about 38
mph versus 33.5 - just as frontal NCAP
tests are conducted at 35 mph instead of 30.
Congress repeatedJy has denied funding
for side NCAP tests but plans to lund them
in fiscal 1997. There's also a reqUirement to
develop a plan for achieving harmonization
with the European standard. Given funds,
the agency's Richard Morgan has promised
that side testing would begin next year.
Most automakers oppose such testing,
contending the side impact standard is
relatively new. There could be problems
with test variability, they say, if the NCAP
side impact is run at a hjgher speed.
An NCAP side test might also accentuate differences between U.S. and European
rule (see MU.S. and European Approaches," p.2). MThere could indeed be continuing and maybe stronger conflicts between
what we would do to meet a [side NCAP
test] and a European performance level,"
General Motors' Paul Eichbrecht explains.
'jOne possibility is, you might have to
throw some very stiff padding at a vehicle
if it doesn't have an airbag."
Mick Scherba, also of General Motors,
adds that "we know by adding that pad-
ding you may in fact reduce TTI but with
the limitations of SID ... and the lack of
biolidellty ... it may be driving us in a direction that doesn't reduce occupant harm.
And if we had a more biofidelic dummy
that gave us more human-like measures in
"[cannot share the view that the
different standards cause divergence in safety designs nor that
higher speeds cause divergence.
They may lead to
some small differences in
safety design, but they
probably will be small. "
James Hackney, National Highway
Traffic Safety Administraiion
the thorax where we Know that injury is important, and in the head like the EuroSID,
we would hopefully be designing an improved product."
(The U.S. side impact standard relies on
the injury criterion, TTI(d), wmle the European directive uses compression-based criteria including V*C. For details and discussion of three side impact dUIIlmies, see
"Differences Among Test Dummjes," p.3.)
Side airbags also might become more
aggressive. MAs you raise the speed of the
side impact, Scherba explains, "you have
even less time than in a frontal crash to
sense the impact and inflate the bag. And
you know what? You're going to put a higher output inflator in the side bag, and then
guess what's going to happen to a cmld
who's asleep against the door when that
side airbag goes off? That's what you need
to think about."
Adding side impacts to NCAP "would
really make it difficult," agrees Sherman
Henson of Ford. "Any chance we would
have of making a similar car for Europe
and the United States would just be taken
away. I don't believe we could any longer
have the same side structure in a car."
Chrysler's Guy Nusholtz says modeling,
"obviously hypothetical," shows adding
side tests to NCAP would exacerbate design differences. "It ended up with larger
pads, more aggressive airbags," he says.
But the agency's James Hackney says
he "cannot share the view that the different standards cause divergence in safety
designs nor that higher speeds cause divergence. They may lead to some small
differences in safety design, but they probably will be small."
When asked if it would be better to wait
until possible harmonization of the U.S.
and European standards, both Morgan and
Why It's So Important: The driver of the Geo Metro (top left) died from skull and cervical fractures at the scene of the crash when her car lOOS
struck in the side by a larger sedan. Two more people died when their Pontiac Grand Am (above left) was struck broudside by a pickup truck.
The driver died of massive injuries to the head and chest, and a rear-seat passenger died of chest and abdomina! injuries. The dn'ver of the Mitsubishi Eclipse (top middle) suffered amnesia, and the Mercury Tracer's (above right) driver suffered a broken collarbone when his car was
struck dUring a right tum. The driver of the Pontiac Grand Prix (top right), struck in the side by a utility Vf'hicle, was admitted to the hospital with
a concussion, two fractures of the pelvis, a rib fracture, and pneumothorax. None of these vehicles wa~ certified to meet the dynamic side impact
protection standard now in effect in the United S)ates, and it isn't known whether the standard would have reduced the injuries. II is known that
U.s. and European safety standards don't address many sources of head injury in side impocts.
Hackney note that while the U.s. standard
has been in place for three years, the Eurcr
peans have yet to begin side impact tests.
Hackney expresses confidence in the
U.s. compliance test and in the prospect
of running it at a higher speed. "We started researching the side impact standard
in the late 1970s, and the research that
went on was very extensive .... There are
always flaws and weaknesses, but we feel
very confident regardless 01 the speed. We
had a lot of variable speeds in our research
program - we did speeds at or near or
even above the proposed NCAP speed so we have quite a bit of confidence that
reductions in the injury criteria of the
dummy will lead to reductions in realworld injuries."
The Institute supports the concept 01 a
side impact assessment program. But In-
stitute President Brian O'Neill explains
that "we have serious reservations about
the direction the agency is taking. Re·
search by the Canadian government and
others has highlighted the inadequacies 01
SID in reliably assessing abdominal injury
likelihood. II doesn't make sense to evaluate side impact protection using an out-oldate and inadequate dummy, especially
when better dummies are available."
10
alU5 Report, VoL 3J. '0. 8, Sept. 28,
/996
gC esfro
uo..a..aa',
.1~1.l.,nere
" and E ope, Officials
P ue Own Side 1m act Standards
The quest to find the b st side Impact
protection standard isn't confined to the
United tates and European Union. Officlals In other countries are considering
their own responses to U,e side Impact
problem. and they're basing their consideratIon on .. and European experience.
Canada, for example, has permitted the
sale of cars that meet .. safety standards. But the . side Impact standard
- pedficaJI the use of SID - has been
ri Iclzed ee IrnIs and th u for a
Dummy to Use orldwide. p.5).
(cording to Transport Canada' Dainiu almotas and others es in Canada
"d on trated that vehicle models designed without the aid of advanced dummi uth as the BioSID frequently howed
c plionally low TIl values when tested
willi th U.. lD but excep 'onally high abdominal deflection, V*C, and force values
wh n tested with either the EuroSID or
BloSID under identical test conditions."
(fhe U. .side Impact tandard relies on
the injury criterion. TIled), while the European directive uses compression-based criteria including V*C. For an explanation of
these and discussion of related issues, see
Differences Among Test Dummies," p.3.)
These researchers conclude that both
e U. . and European tandards could be
satisfied with interior padding but that using a dummy ·capable of supporting deneetion and force criteria." uch as BioSID
r ElIT ID is d irable. They further note
the need to "'monitor the response o[ the
abdomen in any dummy that' used.
"I think anyone who has looked hard at
both ID and TTl has some very basic concerns about them" Eric eJboume oJ Transport Canada points out. "Our preference is
Quite simply to use a measure that directly
bears on the injury risk for internal organs,
which is rib deflection, talking specifically
about the chest. And you've also got essentially abdominal ribs in BioSID . , . which
giv om informative measure of what
going on there."
\ eJbourne reports that Transport Canada, which already has extensive experience with all three side impact dummies,
plans further tests this year with a fourth
one, [[)'lls.
Dynamic side impact test procedur also are under discussion in Australia where
there's a proposal to permit cars to meet
either the U.. or European standard. Tllis
is based on Federal Office of Road Safety
research to estimate the likely beneHts
from using either regulation. The resulting
benefit-cost ratios were about the same1.59 for the European rule and 1.47 for the
U.. standard.
ow Australian reguJators are planning
research to examine the Ukely benefits of
alia ing a thjrd alternative which combin the better features of the 0 regulation and promotes the use of the Hi ID
dummy." In addition to Bio TO, the propo ed hybrid regulation would us the injury criteria associated ith Eur ID. Lo
the extent possible, and it would use the
barrier face specified in the European directive. The impact geometry and u e of
front and rear seat dummies would be according to the U.S. rule.
Australian researchers point out that
finding benefits of the hybrid procedure
equal to or greater than those for the current U.. and European regulation would
support the hybrid test proposal being conidered in international forums as an alternative to those standards.
Japane e analysjs points to adopting
"regulation equivalent to the Earop n
test method with a target date of 0 ~ her
199 . according to the Ministry of Transport and Japan utomobile Manufa ure
ociation. Researchers at th e organization conclude that EUTO ID is more
biofidelic than ID. They further point out
that the frontal dimensions and stiffne s
characteristics of Japanese vehicles are
doser to those of the European barrier
than to the barrier used for compliance
with the U.S. side impact standard.
Status Report, IbI. 31, No. ~ Sept 28, /996 11
When we think of protecting people in side impacts, we think first of protecting the
ones riding closest to the point of impact - the near side - who are more likely to be injured. But don't forget about people on the far side. They're at considerable injury risk,
too, Institute researchers confirm.
The risk among far-side occupants is greatest for the elderly, lor motorists who aren't
using their safety belts, and lor people riding in pickups or utility vehicles. Safety belts are
particularly important. Unbelted occupants on the side opposite the impact point are more
than lour times as likely as belted occupants to be seriously injured.
Overall injury risk is greater in cars than it is in light trucks. Even after adjusting for the
differences in occupant age, safety belt use, and vehicle weight, researchers have found
that occupants seated near side impact points in cars were three times as likely to be seriously injured as near-side occupants in light trucks.
The situation is reversed among far-side occupants. Those in cars were significantly
less likely to be seriously injured than those in light trucks.
Other researchers have reported similar findings. A1984 study from Calspan Field Services reported that, among drivers of cars struck by other cars on the passenger side, the
rate 01 serious injury was IS percent. Among drivers 01 light trucks whose vehicles were
struck by cars on the passenger side, however, the injury rate was 20 percent.
What accounts for this dillerence? It seems as il the people in the light trucks would be
less likely to be injured - not more likely - because their vehicles are heavier than the
cars that hit them. And the ground clearance of light trucks is higher than that of cars, so
the striking cars are more likely to hit the relatively stiff door sill, not the door panel. This
would produce less intrusion into the oc·
cupant compartment of the light truck, so
it seems like injury risk would be reduced.
Yet the risk is actually greater for far-side
occupants in light trucks. To explain this,
the Institute researchers hypothesize that
the cars striking the stiff door sills of the
light trucks could cause higher deceleration forces that contribute to the injury
severity ollar-side occupants,
More often among far·side occupants
than among those riding on the near side,
head and neck injuries are the most severe. The near·side occupants do sustain
head and neck injuries, but they're usually
not as severe as the chest injuries they also sustain.
Understandably, efforts at side impact
protection have focused on near-side occupants, who are at greatest injury risk.
And because these occupants tend to be
better olf in light trucks than in cars, the
trucks generally are considered safer. But
the Institute's new research shows that
far-side occupants of light trucks are at
considerable risk. Although the numbers
in this study are relatively small, the growing popularity 01 light trucks should provide even more evidence of this phenomenon, the researchers say.
Anew federal standard covering head
impacts with upper vehicle interiors may
help reduce the severity 01 both head and
neck injuries in side impacts (see Status
Report, Vol. 30, No. 10, Dec. 2, 1995). This
standard, which covers light trucks as well
as passenger cars, will be phased in over
five years beginning with 1999 models. Also beginning with 1999s, new light trucks
sold in the United States will have to meet
the same dynamic side impact test requirement that applies to cars. Current designs
of most light trucks are expected to easily
meet this requirement.
For a copy of "Side Impact Crashes: The
Relationship of Vehicle and Crash Characteristics to Injury Severitt by C.M. Farmer
et al., write: Publications, Insurance Insti·
tute for Highway Safety, 1005 N. Glebe Rd..
Arlington, VA 22201.
ATUS'~REPORT
1005 Nnrth GlelJe Road
Arlington, VA 22201
(703) 247-15110 FAX (703) 247-1678
http://www.rrwysalety.org
Director of PublicationsjEdilor: Aone Fleming
Writers: Maria Kau(mann, KIm Stewart
Editorial Assistant: Carlene Hughes
Art Director: Joyce Thompson
Graphic Designer. Leslie Oakey
The Insurance Institute (or Highway Safety Is an independenl, nonprofit, scientific ~nd educational organization
dedicated 10 reducing Ihe losses - dealhs, injuries and
property damage - frum crashes all Ihe nalion's high,
ways, The lnstltul.e Is wholly supported by auto Insurers.
Contents may be published whole or In. part with attrlbutiun, This,publlcation is printed on recycled paper.
(1}
ISSN 0018-988X
Vol. 31, 0.8, Sept. 28, 1996
On the Inside
Side impact protection standards in
United tates and Europe go in different directions
p.2
Head protec:tion isn't
addressed in either 0.5.
or European rule ...... p.3
Three dummies in use,
and a fourth is proposed
KiCking A
p.5
Different car designs may result from
different side impact standards
p.6
Adding side tests to NeAP
p.8
Results of real crashes show why side
impact protection is so irnportant....p.9
Others foUowing U.S., Europe ........p.l0
Occupants on side opposite impacts
are at considerable risk, too
p.ll
r0V.
~O'
~ 110 /
'rieL.
'lIn
'{} ...q.s/~
e, Side I
f11pact Issue