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1

Low Delta-V Crashes Resulting in Serious Injury

Mark ScarboroNHTSA

May 16, 2007

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Questions

When occupants are seriously injured at low delta-v’s, what contributes to the injury causation?

What details are required to better analyze this issue?

What does the field data tell us?

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3

NASS Data

0%

5%

10%

15%

20%

25%

30%

35%

40%Pe

rcen

t of C

ases

<=20 kmph >=21kmph UNKNOWN

Delta-V

CDS Data (98-05) Delta-V DistributionCriteriaAges 18+Rollovers excluded

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NASS DataCDS Data (98-05) Delta-V and Injury Severity

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

0 1-2 3+

MAIS

Perc

ent o

f Cas

es

<=20 kmph

>=21kmph

UNKNOWN

52,967Occupants

12,180 Fatals

CriteriaAges 18+Rollovers excluded

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5

Study Group Inclusion

CIREN cases 1997–present Occupant must sustain an AIS3+ injuryAges 18 and up

Winsmash DV <=20 kmph (12.4 mph)N=132Delete any vehicle with a rollover (9)N=123Delete any “Special Interest” cases (1)N=122

Step 1

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Review Vehicle DamageCrash investigator’s estimate of Winsmash validity

(Delta-V versus Crush and/or Intrusion)

10 mph ? 8 mph ? 12 mph ?

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7

Low Estimates Dropped

Typical crashes of concernFLEE’s & FREE’sNarrow impacts with fixed objectsAngled side impacts

43 (35%) cases rated as “low estimate”N=79

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Optimal Restraint Use

Only restrained occupants includedBelt restrained or air bag and belt restrainedUnbelted occupants excluded

Regardless of Air bag deployment21 occupants removed

Occupants with documented belt misuse2 occupants removed

N=56

5

9

Acceptable

Crash conditions and damage appear appropriate

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Group Stats

50%28Female

50%28Male

Gender

2%1Due to disease

7%4Due to injury

Fatalities

62.5%35AB deployed

100%56Belted

Restraint Status

59%331998 and later

Vehicle Model Year

14%8Fixed Object

86%48Vehicle

Opposing Object

64%36Side

36%20Frontal

Crash Type

PercentOccupantsCategory

3008TLOS (days)

123 (271)42 (93)79 (175)Weight kg (lb)

198 (78)147 (58)170 (67)Height cm (in)

54917ISS

533.4MAIS

931861Age

20 (12)9 (6)16 (10)DV kmph (mph)

MaxMinMeanCategory

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Occupant Injury Distribution

AIS 3+ Injury by Body Region

Chest, 45%

Brain / Skull, 29%

Abdomen, 11%

Spine, 9%

Up Ext, 9%

Low Ext, 23%

*56 occupants with 102 AIS3+ injuries

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AIS 3+ Injury Source

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

Perc

ent o

f Inj

ury

Air bag

and/or c

over

Door p

anel

Belt w

ebbin

g/buc

kle

Armres

t/doo

r hdw

Center

cons

ole/flo

or shif

ter

Extern

al ob

ject

Knee b

olster

Seat b

ack

Side window

sill/f

rame

Unknown

B-Pilla

r

Floor pan

Non-co

ntact

Other

interi

or objec

t

Windsh

ield

Component

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13

Contributing FactorsAll cases manually reviewed for factors influencing injury causation and severity (Bio-Tab method)

Age (Elderly)Poor bone quality (osteoporosis)Calcification of vascular structures

IntrusionIntruded component causes or exacerbates injury

Pre-morbid ConditionMedical condition affecting injury causation8Medications, obesity, implants (ortho/organ)

Multiple Impacts / Out of PositionOccupant’s injury impact position is non-optimal

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All cases manually reviewed for factors influencing injury causation and severity

Stature Occupant proximal to injurious components8 Seat track, seated height

CompatibilityStriking vehicle’s height or stiffness is a factor8Usually coded as intrusion, head contact to V2

CargoCargo shifting or moving in the vehicle is a factor8Equipment, pets (large)

Contributing FactorsContinued

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Contributing Factors Distribution(Several can apply)

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

Perc

ent o

f Occ

upan

ts

Age

Intru

sion

Pre-m

orbid

Con

d.

None

OOP/Mult

. Impa

cts

Statur

eCar

go

Compa

tibilit

y

Contributing Factor

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Fatal (crash)4 cases were fatalAll case vehicles were pre-1998Case 1

77 y.o. male, frontal impact, SDH-AB8 Out of position, age and PMH

Case 267 y.o. male, frontal impact, cerebral bleed-AB8 Age

Case 377 y.o. male, frontal crash, cerebral bleed-Medicine cabinet8 Cargo

Case 491 y.o. female, side impact, liver lac-Armrest8 Intrusion and age

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Brain and Skull Injury

16 Occupants with AIS3+ brain or skull injury (25 injuries)

17 kmph avg. (10.6 mph)

Majority of brain injury are cerebral bleeds

Primary source air bag and or related components

44% (7/16) of the occupants were in 1998 or newer vehicles

66% (4/6) of the occupants with AB sources were in 1997 and older vehicles

Avg. age of group=69 - AB group=72

Brain / Skull Injury Sources

0%5%

10%15%20%25%30%35%40%45%

Air bag

and/or

cover

Side wind

ow si

ll/frame

Extern

al obje

ct

Other in

terior o

bject

Belt web

bing/buc

kle

Center c

onsole

/floor s

hifter

Unknow

nPe

rcen

t of B

rain

/Sku

ll In

jury

Brain/Skull Injury Details

0%

5%

10%

15%

20%

25%

30%

Cerebral

contusio

n/hemor.

Cerebral

SDH

Cerebral

SAH

Cerebral

EDH

Concuss

ive

Base s

kull f

x

Brain s

tem co

nt.

Perc

ent o

f Bra

in/S

kull

Inju

ry

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Chest Injury25 occupants with AIS3+ chest injury

(34 injuries)

15 kmph avg. (9.3 mph)

Rib fractures, HTX, PTX and lung contusions are high frequency

Door, armrest and belt are the primary sources

68% (17/25) of the occupants were in 1998 or newer vehicles

Avg. age of chest group=61

Chest Injury Detail

0%

10%

20%

30%

40%

50%

60%

Rib fx +/-HTX/PTX

Lung inj +/-HTX/PTX

Heartcont/lac

Diaphragmrupture

Tracheal inj

Perc

ent o

f Che

st In

jury

Chest Injury Sources

0%

5%

10%

15%

20%

25%

30%

35%

Door p

anel

Belt w

ebbin

g/buc

kle

Armre

st/do

or h

dw

B-Pilla

r

Air ba

g an

d/or c

over

Seat b

ack

Side w

indow

sill/f

ram

e

Unkno

wn

Perc

ent o

f Che

st In

jury

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Lower Extremity Injury13 occupants with AIS3+ LE injury (19

injuries)

17 kmph avg. (10.6 mph)

54% (7/13) occupants were in side impact crashes

Pelvic fractures dominate the LE AIS3+ group

Source is not isolated

62% (8/13) occupants were in 1998 or newer vehicles

Avg. age of LE group=55

Lower Extremity Injury Details

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

Pelvic fx Ankle fx Femurshaft fx

Proximaltibia fx

Distalfemur fx

Proximalfemur fx

Perc

ent o

f LE

Inju

ry

Lower Extremity Sources

0%

5%

10%

15%

20%

25%

30%

Knee bolst

er

Center

conso

le/flo

or shif

ter

Door pan

el

Floor pan

Armres

t/door h

dw

Belt w

ebbing/buck

lePe

rcen

t of L

E In

jury

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Examples

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Case – No Contributing Factors

Case V = 1998 Jeep Wrangler

Crosses center line, bumps curb and strikes 1991 Plymouth Acclaim

PDOF = 0

DV=18 kmph

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No Factors

41 y.o. male driver

Belt and air bag

No past medical

Interview – good recall

No intrusion

Min. crush

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No Factors

Right femur shaft fx

IM rod surgical repair

TLOS = 4 days

Initial charges = $20,686.00

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Case – Contributing Factors

Case V – 1999 Ford Windstar van

V2 – 2005 Jeep Grand Cherokee

T-intersection crash

Nearside configuration

PDOF – 1 o’clock (30°)DV = 11 kmph (7 mph)

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Case – ContributingFactors

62 y.o. male right front passengerPre-morbid conditions

Aortic aneurysmCancerSmoker (1 PPD)AnemicHypertensionAtherosclerosis (aorta/coronary)

Belted – no air bags deployed5 cms related intrusion17 cms crush

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Case – Contributing Factors

Right rib fxs (7-12)

Postero-lateral

Flail chest

Right lung contusion

Right pneumothorax

Right lung laceration

Liver laceration (small)

MAIS=4

ISS=20

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Case – Contributing Factors

Initial hospital stay of 21 days

Multiple respiratory complications

Readmission 3X = 26 days additional

Occupant expired before 12 month F/U

Medical charges 47 days = $171, 037.00

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Findings from CIREN DataSerious injury at low impact speeds

Primarily an older occupant issueNot always

Contributing FactorsMust be captured and documented in detail

Intrusion Much lower than current triage protocol

Detailed past medical historyIndicators for increased severityMultiple possibilities can apply

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Next Steps - CIRENBio-Tab coding to relate contributing factors directly to specific injury

Continue to better define elderly

New side impact vehicle investigation techniques

Improved intrusion, contacts and SAB data

Utilize DICOM images

CIREN and other populations

Document anatomical changes

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Thank YouQuestions?