STEERING WHEEL INDUCED HEAD AND FACIAL INJURIES
AMONGST DRIVERS RESTRAINED BY SEAT BELTS
By
P . F . Gloyns , S . J . Rattenbury , A . Z . Rivlin , H . R .M . Hayes , J .K . Hanstead , S . Proctor
Accident Research Unit , Department of Transportation and Environmental
Planning , University of Birmingham, Birmingham , U . K .
INTRODUCTION
Many field s tudies o f accidents have identi f i ed head and face impacts with
the s t eering wheel as a predictable occurrence for the driver restrained by
a lap-diagonal seat belt (1-8) * . The intentions o f the present paper are two­
fo l d . F i r s t l y , i t examines the frequency o f such head s t rikes for seriously
and fatally injured drivers using an accident sample that i s demons trated to
be representative in terms of poli ce reported variables of a l l accidents in a
large study area . Secondly , the nature o f the injuries resulting from such
contacts are described to help indicate the types of injury t o l erance data
that are mos t appl i cable to this s ituatio n .
THE FREQUENCY OF HEAD CONT�CTS WITH THE STEERING WHEEL
Sample validity
The accident sample used for this part of the s tudy has been c o l lected by
' in-depth ' inves tigat ions conducted by specialist t eams in three s eparate
geographical areas of the United Kingdom. Bas ic data is col lected from the
po l i ce on a l l accidents in the s tudy areas in which an occupant of a car or
light van less than five years old is described as ' seriously ' or ' fatal ly '
The variables recorded on all such accidents are l i sted in
injured ( 9 ) .
Tab l e 1. The s e variables are compatible with those recorded nationally in
the United Kingdom for a l l police reported injury accidents and thus the
study catchnent areas can be examined for the degree to which they are typical
of the whole country ' s accident experience . Accidents meeting the selection
criteria are samp led randomly for ' in-dept h ' investigation and the sample
moni toring s cheme i s used to detect any biases that are inadvertently building
up . The only deliberate bias is that fatal accidents are sampled at a higher
rate than serious injury accidents .
For the current analysis , a l l vehicles studied which were less than f ive years
old and in which a restrained driver was s erious ly or fatally injured were
checked on the basis of the variab l e s shown in Table 1 agains t the group of
vehicles which had not been studied but s ti l l comp l ied with these select ion
The comparison was done s eparately for the two driver injury
criteria .
categories using x2 or the Fisher Exact Probab ility Test ( 1 0 ) , as appropriate .
No s igni f i cant d i fferences at the 5% level of confidence were apparent on the
basis of these variables with the excep tion of one - the vehicles of serious ly
injured drivers contained a higher than expected proportion of f at a l ly injured
*
30
Numbers in brackets refer
to
the references at the end o f the paper .
passengers . This difference i s explained by the higher sampling rate adopted
for fatal accidents noted previousl y . However , the ratio of serious to fatal
accidents is such that only three more s eriously injured belted drivers from
vehicles in which there was a fatali ty were included than would be predicted
on a s trictly repres entative bas i s . Since this bias i s relatively srnall ,
( l e s s than 5% o f the s eriously injured driver sample) , no attempt has been ·
rnade to correct for i t in the subsequent analys i s . Overall the conclusion
of this examination of the samp l e is that the accidents in which there were
restrained drivers appear , in terms of the police recorded variables , to be
a good r e f l ection of all police reported accidents meeting · the appropriate
select ion criteria in our catchment areas .
Representative samp l e of s eriously injured drivers
Our ' representat ive ' sarnp l e cons i s t ing of approxirnately 250 vehicles ,
contained 65 res trained drivers who wer� s eriously inj ured . The locations
of the head and face contacts rnade by th ese drivers are shown in Table 2 .
This table includes a l l accident configurations and demonstrates that for
these drivers the steering wheel is the structure mos t frequently contacted
by the head or f ace . The directions o f force for the whol e s eriously injured
samp l e and f or those 32 vehicles in which the driver made a head or face
contact on the wheel alone are shown in Table 3 . As would b e expected head
or face contacts on the wheel were only observed in irnpacts with a direction
of force between 11 and 1 o ' clock and it is of note that in 6 7% of the cases
with these direc t ions of force such a contact occurred .
For the frontal impacts , the Equivalent Test Speed ( 1 1 ) ha s been used a s an
indicator o f irnpact severity . Table 4 shows the E . T . S . distributions for
all frontal impacts and a ls o for those that r e s u l t ed in a s teering wh eel
hesd or face contact .
Drivers experience head or face contacts with the
s teering wheel throughout the severity range in this sample but there i s a
trend towards a higher incidence o f such contacts as accident s everity
increase s .
Movement o f the steering system during the impact could affect both the
likelihood and s everity of head and face contact on the wheel . The static
intrusions o f the s teering systerns in this sample are shown in Table 5 .
All the vehicles included in this analys i s were fitted with steering systems
co�p lying with the requirernents o f ECE Regulation 1 2 ( 12 ) .
Because
s teering
wheel intrusion i s related to accident severity it i s
difficult t o isolate the influence o f this parameter with a sample of the
present s i z e . lt is of note that whi l s t legis lation exists which l imits the
horizontal movement of the wheel in a frontal barrier tes t , no such control
is exerc is ed over the vertical rnovement of the system. In view of the
apparent head traj ectory adopted by res trained drivers in which the head i s
travel ling forwards and downwards i t s eerns probab l e that some control o n up­
ward movement of the steering wheel would be helpful . lt has been pointed
out previous ly ( 1 3 ) that if effort goes into designing the s teering wheel for
the unrestrained drive r ' s ehest contact the sys tem should remain in an
appropriate p o s ition for that contact in the event o f a frontal impac t . Thus
31
control o f the vertical movement of the wheel would s eem desi rable from both
the restrained and unrestrained driver ' s point of view .
Apart from accident severity and s teering wheel movement , the mechanical
function of the seat belt would be expected to play a part in determining the
frequency and s everity of head or face contact an the wheel . Belt slack , qe l t .
breakage or other unexpected performances o f the restraint sys tem have been
analysed and are presented in suunnary form in Table 6 . Belt performance was
asses sed taking into account the p o sition of material transfer marks an the
webbing and the driver ' s seating posi tion and size . Seat belt problems were
detected in approximately 8% of cases in the samp l e . Such incidents would
be likely to be highly over-represented in a serious injury samp l e because
seat belt malfunction may result in more injury than would have been expected
had the belt functioned correctly . lt i s , however , notable that head contacts
on the wheel are a predictable occurrence for seriously injured drivers who
are wearing seat belts that apparently �unction correctly .
The nature of the injuries sustained by those drivers wh..��e only head arid face
contact was with the s t eering wheel i s presented in Table 7 in terms of AIS
scores ( 1 4 ) '. The surface inj uries to the face are described in Table 8. For
drivers whose only head or face contact· was with the wheel , 62% suffered
highest or highest equal AIS scores as a result of this impac t . The inj urie s
themselves are rarely rated in excess o f AIS 2 and are evenly divided between
facial hone fracture and concus s ion at the more serious end of the spectrum .
Lacerations although f requent were general ly l imited in extent and depth .
As the AIS i s predominantly a ' threat to l i f e ' scale it was considered useful
to describe the wheel induced inj ur i e s u s ing two s cales s e lected from the
Comprehensive Research Injury Scale (CRI S ) ( 1 5 ) . All inj uries suffered
by these drivers were assess ed using the Treatment Period (TP) and Permanent
Impairment (PI) Scales o f CRI S . Where a specific injury was not mentioned
in the CRIS dict ionary it was neces sary to assign it a value in each scale
used . The assumptions made are described in�he appendix and represent the
best estimates that the authors could make of the suitable values . Al though
not used very frequently in the analys i s the results obtained are clearly
affected by the nature of these as sumptions .
Us ing the Treatment Period Scal e , 62% of the drivers who experienced a head
or' face contact on the wheel had the i r highest or highest equal TP score from
this source . This scale thus gives the same weighting to the s e inj uries as
does the AIS . The Permanent Impairment Scale j udged these inj uries to be
relatively more important , resulting in s ome 72% of the drivers who made a
head or face contact with the s teering wheel sustaining their highest or
highest equal PI score from this s ourc e . If the validity o f these scales i s
accepted these results indicate that the head t o wheel impact i s an important
contributor to overall injury amongst these drivers and that its importance
is greates t when inj uries are viewed in the light of their likely contribution
to permanent impairment .
32
Representative samp le of fatally injured drivers
The representat ive samp le contained 76 fata l ly injured drivers of whom 22
were restrained . The steering wheel represented a much less frequent site of
head and face contact than was observed for the seriously injured drivers .
Table 9 describe s the head and face contact s i te s for the fatalities and can
be directly compared with Table 2 relating to the serious inj ury samp le .
Whi l s t 49% of the s er ious ly injured drivers appear to have suffered a s imple
wheel contact only 9% of the fatalities had a s imilar experience . Thi s is
explained in part by differences in driver traj ectory relative to the steering
sys tem. In accidents with maj or intrusion which occur frequently in a
fatal sample , the driver tends to contact the wheel with his ehest rather than
his head . Also there are differences between the configurations of fatal and
serious inJ ury accidents . For the two people among s t the fatalit ies who did
have a head or face s trike on the wheel f only one received his highest equal
AIS s core from this source . Both cases 1 occurred in impacts where the
direction of force was 1 2 o ' clock and both accidents were j udged to have an
E . T . S . in excess of 50 km/h. One case was comp licated by s eat belt mal­
function . With such sma l l numbers it is not appropriate to describe the
samp l e in s imilar detail to the serious accidents but it is hoped that the
analys i s thus far does indicate that the problem of head and face to wheel
contacts is of concern to the s eriously rather than fatal ly injured restrained
driver .
PATTERNS OF INJURY AMONGST RESTRAINED DRIVERS EXPERIENCING HEAD OR FACE
STRIKES WITH THE STEERING WHEEL . NON REPRESENTATIVE SAMPLE .
For this s ection of the analysi s the cases were drawn from the complete data
bank available at the Accident Research Uni t . This data bank cons i s t s o f
more than 2900 cases collected over a ten year perio d . During thi s time
a variety of selection cri teria have been employed ranging from the current
serious and fatal casualty criterion to a previous requirement that any
accident in which a seat belt was used irrespective of inj ury or age of
vehicle would be s t udied . All cases were scanned to select restrained
drivers who had a s imp le head or face strike on the s teering sys tem alone ,
and who were reported by the police to be seriously or fatally inj ured . This
sub-sample which consi s ts of 90 seriously injured d r ivers and three fatali t ies
gives a useful and expanded ins i ght into the nature of head and facial
inj uries result ing· from wheel contact . lt includes the 32 seriously injured
and 2 fatally injured drivers who were identif ied in the earl ier section of
this paper .
Table 10 i llustrates the d i s tribution of d irections of force in the accidents
s e lected . In common with the f indings of the ' representative ' samp le all
such impacts occurred in accidents where the direction of force lay between
1 1 and 1 o ' clock . The severities of accidents i� which these head or face
strikes occurred a�e shown in Table 1 1 and again i t i s apparent that head
to wheel contacts can occur throughout a wide spectrum of accident severities .
Static horizontal wheel intrusion in exces s of S em was present in 39% of this
samp le and vertical wheel movement �as observed in 33% of the cases . All
systems contacted comp lied with ECE Regulation 1 2 .
33
Having described briefly the characteristics of the accidents being analysed ,
the next section will consider details o f the occupants and 1,.the head and face
inj uries they receive d . E ighty-one of the drivers were male and the ages o f
a l l drivers are shown i n Tahle 1 2 . For other hody areas age has heen found to
have a major inf luence on impact · tolerance . There was no s i gnificant
difference at the 5 % level of confidence hetween the age dis tributions o f
those who d i d and d i d no t suffer facial hone fracture from the wheel . This
indicates that whi l s t the facial hones may wel l experience a reduction in
impact tolerance with increasing age , this effect does not appear to pre­
dominate in selecting those who suffer bony inj ury .
The heights o f the drivers were known in 52% o f the cases and they are shown
in Tabl e 1 3 . This table indicates that head and face contacts with the
s teering whee l are experienced hy drivers of a l l heights and are not exclusiv­
ely a problem as sociated with the short individua l . Analysis of the exact
effect of driver height on the likelihood and severity of wheel contact i s
very comp lex and i s beyond the scope of the present paper .
The inj uries produced hy these head and face imp ac t s are described in terms
of AIS score in Table 1 4 , and the nature of the surface inj uries to the face
is shown in Table 15 . These result s can be compared with Tahles 7 and 8 ,
which show very simi l ar patterns o f injury for drivers from the representative
sample . With the increased numbers presented in Tah l e 1 4 , the picture is
s t i l l one in which the great maj or i ty (96%) o f the wheel induced inj uries are
rated at AIS 3 or les s . Surface inj uries to the f ace are common and a
minimum o f 35% o f them require suturing of at least one laceration . Both
facial bone injuries and concussion are seen hut the concuss ion is rarely life
threatening. These injuries will be described in detail in the next section
of the paper . Severe neck injlury does not seem t o he a feature o f these
cases .
The inj uries sustained by the 39 people who suffered bony inj ury are
des crihed in Figure 1 .
This d i agram i l lus trates the dis trihution of the
fractures in tpis samp l e . The injuries are spread throughout the main facial
s tructures with the nasal hone heing fractured mos t frequent l y . Fractures
in more than one of the specified areas were recorded for 36% of these
drivers . The area o f fracture i s inf luenced hy hoth the point o f impact and
the direction of loading hut i t i s hoped that the dis trihution o f inj uries
shown here will help in the selection o f the appropriate inj ury tolerance
for modelling of the head to wheel impact . Clinical j udgement w i l l have to
he comhined with thi s frequency input to reflect the varying difficulties
of treating injuries in different hony areas . For those experiencing some
degree of f acial h one fracture , 49% also suffered some form of concuss i on .
l t i s of interest to note that fractures t o the left side of the face are
over-represented .
This may wel l he associated wi th the :a•ymmet:ry. of the
restraint provided hy the diagonal section of the helt hut the sample is too
small to a llow this hypothesis t o he confirmed .
The nature o f the hrain inj uries suffered hy a l l drivers in this part of the
samp l e is shown in Tahle 1 6 , irrespect ive of the presence of facial hone
fractur e . Over a l l the picture i s one i n which li fe-threatening hrain inj ury
34
i s a rare consequence o f these impacts .
Tabl e 1 7 i l l ustrates the frequencies with which various parts of the s teering
wheel are contacted by the driver ' s head or face . Approximately two-thirds of
the detected contacts were found on the hub and spokes , the areas which could
mos t eas i ly be improved by the use of energy absorbing padding . Very few of
the s tructures contacted o ffered s i gnificant ride-down to the driver ' s head or
face in this sample . l t would seero des irable that wheels be designed which
al low f o r such head and face contacts . Figure 2 i l l u s t rates some examp l e s o f
the types o f des igns encountered i n this s ample where the steering wheel frame
i s e i ther totally exposed o r covered in unyielding o r non energy absorbing
mater i a l . To bui ld a wheel with sufficient depth to provide useful energy
absorpt ion for head and face contacts needs cons iderat ion from the initial
des ign concept of the vehicle package . Space needed for head and face r ide­
down roay o therwise be inadvertent ly utilised for switchgear and s teering locks
whereas if all are considered together init ially there need not necessarily
be conf l i ct . A sugges ted des ign for a wheel incorporating desirable features
is a l s o i l lustrated in Figure 2 .
As p reviousl y di scussed , s eat bel t malfunctions would be expected to be over­
repr e s ented in a serious inj ury sample . Their incidence amongst the belts
used by this samp le of drivers s t r iking their heads o r faces on the wheel is
described in Table 18.
The high· belt malfunct ion r a te i s not typical o f our
over a l l experience of seat belt reliabil ity . ( One may recall that in the
representative cases , l e s s than optimal seat b e l t performance was present in
only 8% of cases and due to the nature of the samp l e this was considered to
be an over-reprasentation) . lt s imply emphas i s e s that if there is incorrect
performance o r usage of the res traint sys tem, a head o r face contact with the
s t eering wheel is a likely consequence . This point i s further reinforced by
the fact that the highe s t proportion of poor restraint (28%) is observed
amongs t the sub-group o f drivers who suffered bony inj ury or concus s i on as a
result o f their contacts . Whi l s t any efforts to improve belt reliab i l i ty
would contribute to reducing the incidence o f head or face to wheel impact s ,
i t should not be forgotten that in this samp l e 80% o f the drivers experience­
ing s uch contacts were wearing belts in which no defect was detected .
S ince only three fatalit ies are present in this expanded s ample nothing can
be added to what has a lready been said in the discuss ion of the representative
sampl e .
TESTS APPROPRIATE TO THE CONTROL OF STEERlNG WHEEL DESIGN FOR HEAD AND FACE
IMPACTS .
Having described the f ield experience o f restrained driver head and face
contacts with the s teering system, it is appropriate to consider the test
methods available which s eek t o mimic this s i tuat ion . No test i s currently
specified in European legi s l at ion to examine this· aspect of s teering wheel
performance but two test methods are proposed for the future which are
poten t i a l ly relevant .
F i r s t ly , i t is understood that agreement has been reached on the form o f a
proposed amendment to ECE Regulation 1 2 in which a headform test s imilar to
that currently required in ECE Regulation 21 ( 1 6 ) may be applied to the·
s teering sys tem. The three q ue s t ions that are p o s ed by such a test are : -
35
1)
I s the trajectory appropriate?
2)
I s speed o f impact suitable?
3)
Is the injury criterion relevant?
Head traj ectory
It should be remembered that ECE Regulation 21 was derived from FMVSS 201 ( 1 7 )
i n which an attempt was being made t o model head contacts made by lap-belted
occupants on the facia . How closely thi s traj ectory approximates to that
adopted by the lap -diagonal restrained driver ' s head prior to wheel contact
is not known . However , whil s t the early part o f a lap-diagonal res trained
driver ' s head traj ectory may be s imilar to that o f his lap-belted counterpart ,
the later stages are likely to be quite different in that the presence o f upper
torso restraint s lows the thorax and caupes the head to rotate and travel down­
wards . The movement o f the head relative to the s teering wheel in reality
must be dependent on where in the traj ectory impact occur s . The head impact
with the wheel is further comp licated by the p o s s ibility of dynamic movement
o f the steering sys tem prior to contact . The combined effect of these two
variables s u�ge s t s that it would be des irable to conduct a headform test over
a wider range of ' angles of attack' tharr the limited requirements of the
proposed standar d .
Speed o f impact
The headform would b e required to s trike the wheel surface at 25 km/h o r
less under current proposals . Indications from dummy tests are that i n a
SO km/h s led tes t , head to wheel speeds for restrained drivers may b e well
in excess o f thi s , perhaps in the range of 30 - 40 km/ h . This would seem t o
be an area worthy o f exp loration a s the headform · teat may be i n <langer o f
considerably under-es t imating the energy to b e control led at head s trike .
Again the dynamic movement of the wheel prior to and during head impact may
e ffect the energy to b e absorbe d . and wi l l further comp licate a s s e ssment o f
what constitutes a realis t i c value .
The injury criterion
It has been demonstrated that the more severe inj uries are dis tributed between
facial bone fractures and concuss ion . The criterion currently appl ied to the
headform, requiring that decelerat ions in excess of 80g do not occur for
periods o f more than 3ms , i s intended to relate to concussion type inj uries .
With a headform with an effective mass o f 6 . 8 kg the permissible contact
force i�p l ied by su�h a criterion is considerably above the fracture threshold
thought to be appropriate to the main facial bones ( 18 - 2 1 ) . In view o f the
nature of the inj uries sustained from the wheel , there would seem to be grounds
for considering a reduction of the permi s sifule ' g ' levels in the headform tes t .
The s econd form o f test being considered which may influence s teering sys tem
and res traint design i s the ' integrated tes t ' where an anthropomorphic dummy
i s used in the vehicle in a crash tes t . Such a ' one shot ' test i s not , in our
view, inherently suitable for testing the range o f impact oonditions l ikely to
be experienced in practice and would need to be supplemented by some component
procedure , s uch as a mod i f ied headform tes t , to ensure a suffi c i en t ly ver s at i le
performance from the wheel . The earlier comments relating to injury criteria
36
apply equal ly to the dummy to be used in the integrated tes t . In addition the
adequacy of the dununies to reproduce life-like forward head excursions mus t be
ques tioned . If dununy chests are s t i ffer than those of l ive humans it might be
expected that a dummy tes t would tend to underestimate the amount of forward
movement of the head .
LITERATURE REVIEW
The importance of the steering wheel as a s ignificant source of head and facial
inj uries has been recognised by many authors ( 4 , 5 , 6 , 7 , 2 2 ) , a lthough few of
these present the frequencies of such contacts . Exact comparisons of the
frequencies reported elsewhere are difficult because o f the varying bases of
such f igures . For example , Dalmotas ( 1 ) reports that 81% of facial inj uries
of AIS 2 and above in a l l accident configurations for serious ly injured bel ted
drivers are caused by the wheel with this figure r i s ing to 9 5 % when only
frontal impacts are considered . Thomas e t a l (3) indicate by comparison that
in frontal impacts of all inj ury severitles , 15% of the belted drivers s trike
the s t eering wheel . In the representative sample o f the present paper i t has
been noted that 6 7% of serious ly inj ured belted drivers in frontal impacts make
a head o r face contact on the wheel , not always causing inj ury .
Less than optimal seat belt performance has been reported as a contributory
factor for the occurrence of head or face contacts by other authors ( 2 , 23 , 2 4 ,
2 5 ) wi th s lack belts being c ited a s the mos t corrnno n faul t . Also the un­
desirab l e inf luence of wheel intrusion has been recorded (2 , 5) . l t i s widely
recommended ( 1 , 4 , 22-26) that the wheel is re-designed to offer better pro­
tection for the head and face .
There would appear to be l i ttle irtformation from other s ources on the detailed
nature of the injuries to the head and face from the wheel , data essential to
those draft ing standards which may be needed t o protect this body are a . Three
authors report that the wheel i s a s ource of concussion (6 , 2 3 , 2 7 ) while others
note f acial bone fractures (6 , 25 , 28 ) . In general the number of cases included
in these papers is far smaller than the present paper in which there are 39
instances of facial hone fracture and 41 cases of brain injury of all sever­
i ties . Al l these sources agree that it is rare for inj uries from the wheel to
exceed AIS 3 .
CONCLUS IONS
1.
Representat ive serious inj ury s ample
From a sample of 65 cases in which a seat belted driver was · serious ly
inj ure d :
(a) I n a l l accident configurations 5 2 % of drivers s t ruck the steering wheel
wi th their head or face .
(b) In the 49 impacts with a direction of force between 1 1 and 1 o ' clock 6 7%
o f drivers made the i r only head or face eontact on the wheel .
Of these
32 drivers (i)
9 4% had. head or face injuries r�ted below AIS 3 .
( i i ) - 84% �uffered sooe surface inj ury to the face ; · a t least 22% had
lacerations requiring suturing .
--
37
(iii)
(iv)
(v)
(vi)
(vii)
2.
3.
31% suffered a facial bone fracture .
22% received some level of concussion , and this was rarely in
excess of AIS 2 .
62% sustained their highest or highest equal AIS and CRIS
Treatment Period scores as a result of steering wheel contact .
72% sustained their highest or highest equal CRIS Permanent Impair­
ment score as a result of s teering wheel contact .
87% o f these contacts occurred in accidents where the E . T . S . lay
below 50 km/h .
Representative fatal inj ury samp l e
Fron a samp le o f 22 cases i n which seat b e l ted drivers died , only 2 (9%)
struck the wheel with th�ir head and face . Both of these were involved
in accidents where the E . '.L' . S . was grea ter than 50 km/h .
Non - representat ive sample
Anongst the group of 90 seriously injured restrained drivers who s truck
the s t eering wheel with their head o r face :
(a)
80% o fl the contacts occurred at an E .T . S . below 50 km/ h .
(b)
9 6 % o f the head and face injuries from the wheel were AIS 3 or less .
(c)
At least 35% of the facial lacerat i ons required suturing .
(d)
Whi l s t fractures were observed in a l l the maj or facial bones , the nasal
hone was the one most frequently involved .
(e)
Concussion rated in excess of AIS 2 was rare .
(f)
49% of those suf fering facial hone fracture also experienced s ome degree
of concuss ion .
(g)
Seat belt malfunction is over-represented in this group of c ases .
APPENDIX
Values inserted in the Treatment Period and Permanent Impairnent Scales of
the CRIS .
TP
PI
2
Face
sutured laceration
1
1
1
Chest s imple rib fracture
2
displaced rib fracture
2
ACKNOWLEDGEMENTS
The authors would l ike t o acknowledge the financial support provided for
this work by the Department of Transport , B . L . Cars Limited , Ford Motor Oompany
Limi ted , and Vauxhall Motors Limited.
The task of collec ting the field data was shared between the authors and the
specialist teams o f Department o_f Transport personnel and in particular our
thanks go to Bob Rol l i s , Mike Hough�on , Chris Worton, Les Coles , Harry Hanwe l l ,
Ian Jackson , Gordon Whittaker and Peter Kipling for a l l they have contributed
to the proj e c t .
38
Work such as this requires c o-operation from countless people in the police
forces , hos p i tals , and recovery garages throughout our catchment areas , and
without their wil ling help our s tudies could not cöntinue . Our thanks
especially go to the l ate Professor Gissane and to Dr . J .P . Bu l l and Mis s B .
Roberts at Birmingham Accident Hospital who p layed s o central a part in
collecting the inj ury information .
The support of a l l the o ther members o f the Accident Research Unit is also
gratefully acknowledged .
This paper i s pub lished with the permiss ion of the Secretary o f State for
Transport who does not necessarily agree with any of the views expressed in
it.
REFERENCES
1.
Dalmotas , D . J . Mechanisms o f Inj ury to Vehicle Occupants Restrained by
Three-Point Seat Belts . Proc . 24th Stapp Car Crash Conf . , S .A . E . ,
Warrendale , Penn . , 1 9 80 , Paper No . 801311 , pp 441-476 .
2.
Hartemann , F . ,Tarriere , C . , Mackay , G . M . , Gloyns , P .F „ Hayes , H .R . M . ,
Cesari , D . and Rame t , M . How to Further Improve the Protection o f
Occupants Wearing Seat Belts . Pro c . 19th Annual ConfereCJ.ce c f A . A . A . M . ,
A .A .A .M . , Lake Bluff , I l l inois , 1 9 75 , pp 36-4 8 .
3.
Thomas , C . , Faverj on , G . , Henry C . , Tarriere , C . , Got , C . and Patel , A .
Comparative Study o f 1 6 2 4 Belted and 3242 Non- Belted Occupants : Results
on the Effec tivenes s o f Seat Belts . Pro c . 2 4 th Annual Conference of
A . A . A .M . , A .A . A . M . , Morton Grove , I l l inois , 1 9 80 , pp 422-436 .
4.
Grattan , E . , Clegg, N . G . and Wall , J . G . Intercranial or Neck Inj ury in
Belted Car Occupants . Proc . Int .Conf . on the Biomechanics of serious
trauma , I . R . C . O . B . I . , Lyon , 1 9 75 , pp 1 14-121 .
5.
Bourret , P . , Corbe l l i , S . and Cavallero , C . Inj ury Agents and Impact
Mechanisms in Frontal Crashes about 350 in the Field Accidents . Proc .
2 l s t Stapp Car Crash Conf . , S . A . E . , Warrenda l e , Penn . 1 9 7 7 , Paper No .
7 70919 , pp 2 15-25 8 .
6.
Wal z , F . , Niederer , P . , Zoll inger , U . and Renfer , A . Analys i s o f 115
kil led and 205 Severely Inj ured (OAIS � 2) Seat Belt Users . Pro c . 6th Int .
Conf . , I .A . A . T .M . , 1 9 7 7 , pp 392-406 .
7.
Sabey , B . E . , Grant , B . E . and Hobb s , C .A. Alleviation o f Inj uries by Use
o f Seat Belts . Proc . 6th Int .Conf . , I . A . A . T . M . , 1 9 7 7 , pp 4�0-484 .
8.
Nordento f t , E . L . , Nielson , H . V • • Eriks en , E . and Weeth , R . Effect o f
Mandatory Seat Belt Leg i s l at ion i n Denmark , with Special Regard to
Minor and Moderate Inj ury . Proc . 6 th Int . Conf „ L.A;.A . T .M . , 19 7 7 , pp 72-79 .
9.
Department of Transport . Ins tructions for the completion of Raad Accident
Reports . S tats . 20 . 1 9 7 7
39
10 .
Siegel , S . , Nonparametric Statistics for the behavioural sciences .
McGraw Hil l , 1956 .
11.
Mackay , G . M . and Ashton, S . J . Injuries In Col l i s ions Involving Sma l l
cars I n Europe . Int .Auto . Eng. Cong . , S .A . E . , New York , 1973 , Paper No .
7 30284 .
12.
United Nations . Regulation 1 2 . Uniform provisions concerning the approval
of vehicles with regard to the protection of the driver against the
steering mechanism in the event of impact . E /ECE/TRANS /505 Rev . l /Add .
12 /Revis ion 1 .
13.
Gloyns , P . F . , Hayes , H . R . M . and Rattenbury , S . J . Protection o f The Car
Driver from Steering System Induced Inj uries . I .Mech . E . , London , 1980 ,
Paper No . C l 7 9 / 80 .
14.
American Association for Automotive Medicine . The Abbreviated Inj ury
Scal e . ( 1 9 80 Revision) . A . A . A .M . , Morton Grove , Ill inois . 1 9 80 .
15 .
State s , J . D . The Abbreviated and Comprehensive Research Injury Scale s .
Proc . 13th Stapp Car Crash Conf . , S .A .E . , Warrenda le , Penn . , 1969 , Paper
N o . 69 ? 810 . pp 282-294 .
16 .
United Nations . Regulation 2 1 . Uniform provisions concerning the
approval of vehicles with regard to their interior f i t t ings . E/ECE/
TRANS /505 Rev . l /Add . 12 /Revision 1 .
17.
Department of Transportat ion . Code of Federal Regulations . Title 49
Part 5 7 1 . 201 . pp 295-29 7 . Washington D . C . 1 9 7 9 .
18.
Nahum, A . M . , Gatts , J . D . , Gadd , C . W . and Danforth , J . Impact Tolerance
of the Skull and Fac e . Proc . 1 2th Stapp Car Crash Conf . , S . A . E . , New York ,
1 9 6 8 , Paper No . 680785 . pp . 302-31 7 .
19 .
Swearingen , J . J . Biomechanics o f Facial Inj ury . The Prevention o f
Highway Injury. Highway Safety Research Institute , The Univer s i ty o f
Michigan, Ann Arbor, 1967 , p p 1 5 7-168 .
20 .
Synder , R . G . Human Impact Tolerance . 1 9 70 International Automobi l e
Safety Conference Compendium. S .A . E . Inc .New York . Pub .No . p-30 , 1 9 70 ,
Paper No . 70039 8 . pp 712�782 .
21.
22.
Nahum, A . M . The Biomechanics o f Maxi l lofacial Trauma . Clinics in P lastic
Surgery , 1975 , � . l , pp . 59-6 4 .
Hobbs , C .A . The Effectiveness of Seat Belts in Reducing Inj uries to
Car Occupants . T . R . R . L . Laboratory Report 81 1 , 1 9 7 8 .
23.
Dalmota s , D . J . and Keyl , P .M . An Investigat ion into the Level o f
Protect ion Afforded t o Fully Restrained Passenger Vehicle Occupants .
A .A . A . M . Quarterly/Journal , Apr i l , 1979 .
24.
Anders son, C .E . , Backstrom, C . G . , Forsman , E � , Gustafsson , H . , N i l s son ,
L . E . , Nygren , A . and Wersa l l , J , Facial , Head and Neck Inj uries
Originat ing from Road-Traff i c Accidents , Proc . Int . Conf . on the Bio­
mechanics of Trauma , I .R . C . O . B . I . , Lyon , 1979 . pp 250-26 3 .
25 .
McLean , A . J . and Aus t , H . S . Seat Belt E ffectiveness in Urban Crashes .
Proc . 6th Int . Conf . , I .A . A . T . M . , 1 9 7 7 , pp 160-16 7 .
40
26.
Hartemann , F . , Thomas , C . , Henry , C . , Foret-Bruno , J-Y . , Faverj on , G . ,
Tarriere , C . , Got , C . and Pat e l , A . Belted or Not Belted : The Only
Difference Between Two Matched Samples of 200 Car Oc·cupants . Proc . 2 l s t
Stapp Car Crash Conf . , S .A . E . , Warrendale , Penn . , 1 9 7 7 . Paper No . 7 709 1 7
pp 9 7-150 .
27.
Cesari , D . and Ramet , H . Evaluation of Human To lerance in Frontal Impacts
Proc . 23rd . Stapp Car Crash Conf . , SA .E . , Warrendale , Penn . 1 9 7 9 , Paper
No . 791032 , pp 873 - 9 1 4 .
28.
Hurphy , H . J . , Huelke , D . F . and Sherman , H . F . Case Descriptions o f Lap
Shoulder Belted Occupants in Car Crashes . International Automo tive
Engineering Congress and Expos it ion . , S .A . E . , Warrendale , Penn . , 1 9 7 7 ..
Paper No . 7 7015 1 .
Tab l e 1 .
Variables record+d in sample r.1.onitoring scheme
Overturning
Highes t Inj ury Class in Vehicle
·
Number of Injured Occupants in Vehicle
Year of Vehicle Registration
Age of Vehicle
For each Injured Occupant
Inj ury Severity
Age
Sex
Seat belt use
P o s i t ion
Time
Day of Week
Month
Road Type
Environment
Speed Limit
Light ing
Junction Detail
Number of Vehicles involved
Obj ects s truck
Table 2 .
Representative sampl e o f seriously injured res trained
drivers . Location of head and face contac t s .
Location of head and face contact
No .
%
No head or face contact
Steering wheel only
Obj ective evidence of contact
Imp l ied contact*
Steering wheel + o ther s i te
Other s ite only
S i t e not known
18
28
22
10
2
11
2
34
15
3
17
3
65
100
Total
* In these cases , an inj ury was p resent which i t was thought could only have
been caused by a contact on the s teering wheel , a lthough there was no
phys i ca l evidence of such a contact on the wheel . Contact on any other site
was cons i dered to b e extremely improbable having regard for the accident
configuration , vehicle damage and .nature of the inj ury .
41
Table
J.
Representative samp l e. . o i: s,�riou s ly injured res trained· drivers .
Direction of force o f principal impact .
Sample
Whol e sar.1p le
Head or face contact on
wheel
Table 4 .
ß
9
10
11
12
N/K
0
0
1
0
0
2
6
36
7
0
0
0
0
0
0
1
29
0
3
4
s
7
4
2
0
2
0
0
0
J
S l-60
Une lass
10
16
4
9
4
8
14
4
0
6 7%
80%
87%
100%
21-30
All frontals
3
6
Frontals with head or
face contact on wheel
2
67%
: with bead or face
contact on wheel
S.
„
km/h
41-SO
l l-20
E .T . S .
31-40
of s e r i ous ly injured res trained
Steering wheel intrusion in frontal impact s .
Representative sampl e
Samp le
<
All frontals
Frontals with head or face contact
on wheel
Samp le
All frontals
Frontals with head or face contact
on wheel
42
7
2
Representative sample of seriou s ly injured res trained drivers .
Equivalent Tes t Speed dis tribution for frontal impact s .
Sample
Tab l e
D i rect ion of Force
0
1
<
Sem
drivers .
Horizontal Wheel Intrusion
>
S-1 2cm
1 2 cm
32
7
9
24
4
4
Sem
Vertical Wheel Intrusion
>
S-12cm
12cm
36
9
3
24
6
2
Tabl e 6 .
Representative sample o f seriou s ly injured restrained drivers .
Seat belt performance .
Seat b e l t performed
satis factorilv
Seat belt problem
detected
All frontals
44
4
Frontals with head or
face contact on wheel
29
3
% o f drivers making head
or f ace contact on wheel
66%
75%
Samp l e
Table 7 .
Representat ive sample of serious ly inj ured restrained drivers .
Nature o f inj uries from steering wheel contact .
Body Area
Inj ury Description
AIS Score
0
1
2
3
1
He ad and face
Highest AIS
2
18
10
Face
Surface AIS
5
26
1
Face
Skeletal AIS
22
4
He ad
Surface AIS
29
4
He ad
Skeletal AIS
31
He ad
Internal AIS
23
2
Neck
Highest AIS
30
2
Table 8 .
2
1
4
5
1
2
1
1
6
Representative sample of seriously injured restrained drivers .
Nature o f surface injuries to the face .
Nature o f Injury
No .
No surface injury
Brui se only
Abrasion only
Laceration (s ) , no known s titches
Lacerat ion <3cm long, st itched
Laceration >3cm lon g , s t i tched
More than 1 stitched laceration
5
6
2
12
2
3
2
43
Tahle 9 .
Representative sample of fatally injured res trained dr ivers .
Locations of head and face contac t s .
No .
%
No head or face contact
9
41
Wheel only ; ohj ec tive evidence of contact
2
9
Other site only
10
45
S i t e not known
1
5
22
100
Location o f head and f ace contact
Total
Tahle 10.
j
Non-representative sample of seriously injured restrai:J:·i. . · river s .
Direct ion o f force o f principal impact .
Direction of Force
No .
Tahle 1 1 .
12
1
5
79
6
Non-representative sample of seriously injured restrained dr ivers .
Equivalent Test Speed distr ihution of frontal impact s .
11 - 20
2 1 - 30
3 1 - 40
3
15
18
No .
Tahle 1 2 .
11
E . T . S � km/li
4 1 - 50
5 1 - 60
6 1 - 70
N.K.
32
15
2
5
Non-representative sample of seriously injured restrained drivers .
Age distrihut ion.
Driver Age
10-19
20-29
30-39
40-49
50-59
60-69
70-79
N.K.
Facial hone
fracture
1
9
18
4
1
2
1
1
No facial
hone fracture
4
13
13
11
3
6
1
2
Total
5
22
31
15
4
8
2
3
44
Table 1 3 .
Non-representative sample of seriously injured restrained drivers .
Height Distribution.
Height cm.
160-1 64
165-169
1 70-1 74
1 75-179
1 80-184
1 85-189
190- 1 9 4
N .K .
4
4
12
12
13
0
2
43
No.
Non-representative sample of serious ly injured res trained drivers .
Nature of inj uries from s teering wheel contact .
Tabl e 14.
AIS
Score
Inj ury description
0
1
2
3
4
5
He ad and face
Highest AIS
2
35
33
16
3
1
Face
Highest AIS
9
51
18
12
Head
Highest AIS
46
2
30
8
3
1
Neck
Highest AIS
88
2
Body Area
Non-representative sample of seriously injured restrained drivers .
Nature of surface facial inj uries .
Table 15 .
Nature of Injurv
No .
No surface injury
13
Bruise only
13
Abrasion only
Laceration ( s ) , no known s t i t ches
8
30
Laceration <3cm lang, s t i t ched
6
Lacerat ion >3cm lang , s t itched
12
More than
1
s t itched lacerat ion
Injury presen t , nature not known
7
1
45
Table 1 6 .
Non-representative sample of seriously injured res t rained drivers .
Nature o f brain injurie s .
Nature of Injury
No .
None
49
Headache or dizziness
2
Concussion , unconscious less than 15 mins
32
Concus sion , unconscious 15 mins t o 1 hour
3
Concussion , unconscious 1 hour to 2 4 hours
2
Concus sion , unconscious more than 2 4 hours
1
Brain contusion , some hemiparesis
1
Table 1 7 .
Non-representative s ample of seriously injured restrained drive r s .
Part of steering wheel impacted .
Part of wheel
No .
Hub alone
16
Spoke alone
16
Rim alone
20
Hub and spoke
4
Hub and rim
2
Not c learly defined
Table 1 8 .
32
Non-representat ive sample of seriously injured restrained drivers .
Seat belt performance .
Seat belt perf ormance
No .
Normal
72
Webbing failure
5
Hardware failure
2
Inertia reel malfunction
4
Exces s ive bel t s lack
5
Bad b e l t geometry
1
Multiple prob lern
46
1
FRONTAL
BONE
3
NASAL
BONE
20
ORB I T
7
MAX I LLA
7
ZYGOMATI C
BONE & ZYGOMA
8
TE ETH
6
F I GURE 1 .
D I ST R I BUTION OF FAC IAL BONE FRACTURES .
47
FIGURE 2 .
EXAMPLES OF STEERING WHEEL DESIGN .
Examp l e o f current wheel
w i t h ' u nprotected'
spokes and h u b .
(b)
�
[D ij a:J
Exam p l e of current wheel
w i t h s ki nned foam or
polypropylene mo u l d i ng
over frame.
I
(c)
Exampl e of des i ra b l e
wheel design concept
featu r i n g :
1)
D
48
2)
wheel frame ahd
col umn end
protected by
E . A . pad.
Large area , we l l
supported p a d ,
w i t h s e l f a 1 i g n i ng
properties for un­
restrained dri ver
protec t i o n .