ISO/TR 14646:2007

TECHNICAL ISO/TR
REPORT 14646
First edition
2007-10-15

Road vehicles — Side impact testing of
child restraint systems — Review of
background data and test methods, and
conclusions from the ISO work as of
November 2005
Véhicules routiers — Essais de choc latéral pour systèmes de retenue
pour enfants — Revue des données de référence et des méthodes
d'essai, et conclusions du travail de l'ISO jusqu'en novembre 2005




Reference number
ISO/TR 14646:2007(E)
©
ISO 2007

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ISO/TR 14646:2007(E)
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ISO/TR 14646:2007(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Accident statistics.1
3 Side impact test methods for cars.4
3.1 European side impact test methods.4
3.2 US side impact test methods .5
3.3 Japanese side impact test method.6
3.4 Australian side impact test method.6
4 Child related properties of car side impact test methods.7
4.1 Boundary conditions for a CRS side impact test procedure.7
4.2 Door intrusion depth.7
4.3 Door intrusion velocity from ECE tests .8
4.4 Door intrusion velocity in car-to-car tests.10
4.5 Struck car acceleration and velocity change .13
4.6 Deformation profiles .14
4.7 Dynamic force-deflection characteristics of door interior .15
4.8 Door window sill height and distance to door trim.16
5 Requirements for the side impact test procedure .17
5.1 Test severity.17
5.2 Validation.18
5.3 Repeatability and reproducibility.18
5.4 Field of application.18
6 Historical overview.18
7 Current side impact test procedures for child restraint systems .20
7.1 ISO/DIS 14646 / TRL test procedure .20
7.2 TNO test procedure .23
7.3 TUB test procedure .23
7.4 ADAC test procedure .23
7.5 Australian Standard AS/NZS 1754 test procedure.23
7.6 Australian CREP test procedure.23
8 Conclusions .24
Annex A (informative) ISO/DIS 14646-1.2: ISO side impact test procedure for rearward-facing child
restraint systems.25
Annex B (informative) Working draft of planned future ISO/TR 14646-2, ISO side impact test
procedure for forward facing systems.36
Annex C (informative) Voting results and comments received on ISO/DIS 14646:2003.39
Annex D (informative) Voting results and comments received on ISO/DIS 14646-1.2:2005 .45
Glossary .49
Bibliography.50

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ISO/TR 14646:2007(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In exceptional circumstances, when a technical committee has collected data of a different kind from that
which is normally published as an International Standard (“state of the art”, for example), it may decide by a
simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely
informative in nature and does not have to be reviewed until the data it provides are considered to be no
longer valid or useful.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO/TR 14646 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 12,
Passive safety crash protection systems.
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ISO/TR 14646:2007(E)
Introduction
ISO/TC 22/SC 12/WG 1 has been working on the definition of a side impact test procedure for child restraint
systems. After meeting the deadline for finalisation of a third DIS version and with disapprovals (by a small
margin) of the previous two DIS votings, it was decided to finalise the current project with a Technical Report
and to restart the process of developing an international standard.
The aim of this Technical Report is to summarise the work done within ISO, and to compile additional relevant
information to form a solid base for the restarted project.

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TECHNICAL REPORT ISO/TR 14646:2007(E)

Road vehicles — Side impact testing of child restraint
systems — Review of background data and test methods, and
conclusions from the ISO work as of November 2005
1 Scope
This Technical Report summarises the work within ISO to define a side impact test method for child restraint
systems (CRS). It presents the main background data, and experiences from crash tests carried out during
the process of development. Additional relevant data are also presented.
2 Accident statistics
The severity of injuries in side impacts depends on the seating position. It can be noticed that the severity of
injuries is much higher for children sitting on the struck side than sitting on the non-struck side. The share of
injuries on the non-struck side is comparable to frontal impacts, while the injury probability is much higher in
struck side accidents, see Figure 1.
frontal (n=1408) struck side (n=177) non-struck side (n=282)
1
0,9
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0
overall head neck/spine/back chest/abdomen extremities

Figure 1 — Injury frequency depending on the impact direction [Arbogast, 2004]
Even when analysing all lateral impact accidents the relative number of children suffering MAIS 2+ injuries is
much higher than for other impact directions, see Figure 2.
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weighted injury frequency [%]

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ISO/TR 14646:2007(E)
400
involved children children with MAIS 2+
350
300
250
200
150
100
50
0
front side rear roll over

Figure 2 — Share of different impact directions [Langwieder, 2002]
Regarding the different body regions the risk for severe injuries decreases from the head down to the legs.
The frequently observed injuries of arms and legs are not of high severity, but may cause long term
impairments. The focus for investigations concerning improvements of CRS should be on the head, neck and
thorax, see Figure 3.

Figure 3 — Injury risk of different body regions of 68 injured children in side impacts
[Langwieder, 1996]
Looking at the development of injuries in lateral impacts from 1985 to 2001 it is obvious that the injury
probability decreased since 1985 while the risk to suffer neck injuries increased and the chest remained
unchanged, see Figures 4, 5, and 6.
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no. of children
injury frequency of injured children [%]

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ISO/TR 14646:2007(E)

Figure 4 — Injury probability of different body regions in side impact accidents between 1985 and
1990 [Otte, 2003]


Figure 5 — Injury probability of different body regions in side impact accidents between 1991 and
1996 [Otte, 2003]

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[%]
[%]

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ISO/TR 14646:2007(E)

Figure 6 — Injury probability of different body regions in side impact accidents between 1997 and
2001 [Otte, 2003]
The presented accident shows that side impact accidents are severe ones especially for those children sitting
at the struck side. Especially head, neck and chest need to be protected.
In a study of Swedish accident situation Jakobsson et al. [Jakobsson, 2005] did not find any moderate-severe
(AIS2+) head injuries in children using rear-facing (RF) CRS involved in lateral impact accidents, while
children using forward facing (FF) booster seats or the car belt only suffered from moderate-severe injuries
(AIS2+) in side impacts. Comparing the injury risk for RF and FF CRS in frontal and lateral impact accidents of
NASS Data (US American accident data base) of the years 1988 to 2003 Crandall et al. [Crandall, 2005]
observed a ratio of 4,32 in favour of RF seats. The ratio was felt to be larger than expected.
3 Side impact test methods for cars
The full-scale test methods have been validated against the real world accident conditions in the specific
regions. We can therefore utilise these test methods in the development of the child side impact test
procedure.
3.1 European side impact test methods
In Europe the compulsory side impact test method is described in ECE Regulation No. 95. In addition Euro-
NCAP defined a side impact test procedure, which is similar to ECE Regulation No. 95.
3.1.1 ECE Regulation No. 95
A moveable deformable barrier (MDB) strikes the test car with a velocity of 50 km/h in an angle of 90°. The
barrier has a weight of 950 kg and a width of 1 500 mm. The deformable element has a ground clearance of
300 mm. The centre line of the MDB should match with the X position of the hip point of the 95-percentile
dummy (R-point). A Euro SID dummy is positioned in the driver’s seat. No child dummies are prescribed for
ECE Regulation No. 95.
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[%]

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3.1.2 Euro-NCAP lateral test
The Euro-NCAP side impact test protocol is in most parts similar to that of ECE Regulation No. 95. The most
important differences to ECE Regulation No. 95 are that an ES2 dummy is used in the front driver’s position
and child dummies are used in the rear. The two following opportunities for the CRS installation are possible:
⎯ P1.5 on the struck side and P3 on the non struck side;
⎯ P1.5 on the middle rear seat and P3 on the struck side.
If a head protection system is available in the car, it can be tested in a pole test. The car travels with a velocity
of 29 km/h laterally into a rigid pole with a diameter of 254 mm. No child dummies are used in this test.
3.2 US side impact test methods
The compulsory side impact test method in the US is defined in FMVSS 214. In addition consumer tests are
defined by US-NCAP and IIHS.
3.2.1 FMVSS 214
A crabbed barrier hits with a velocity of 54 km/h the stationary test car, see Figure 7. Because of the 27° angle
of the barrier the velocity has a component of 48 km/h in the car Y-direction and 25 km/h in car X-direction.
The X component should simulate that the struck car is moving in normal lateral accidents. The barriers face
has a width of 1 676 mm and a ground clearance of 279 mm. The “bumper part” of the deformable element
has a ground clearance of 330 mm. The mass of the trolley is 1 368 kg. US SID dummies are used at the front
and rear struck side seat. No child dummies are tested according to FMVSS 214.

Figure 7 — Impact configuration according to FMVSS 214 [NHTSA, 2003]
FMVSS 201 describes a pole test, which formed the basis for the Euro-NCAP pole test described above.
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ISO/TR 14646:2007(E)
3.2.2 US-NCAP lateral test
The US-NCAP side impact test procedure is analogous to the FMVSS 214 protocol. The main difference is
that the impact speed is 5 mph higher in the NCAP test compared to FMVSS 214. This means an impact
velocity of 62 km/h representing 55 km/h in car Y direction and 30 km/h in X direction.
3.2.3 IIHS lateral test
The Insurance Institute for Highway Safety (IIHS) defined a more severe side impact procedure, which should
represent accidents with SUV.
A trolley with a mass of 1 500 kg hits the car in a purely lateral impact with a velocity of 50 km/h. The ground
clearance of the barrier face is 379 mm, while the ground clearance of the bumper element is 430 mm. The
shape of the barrier element shall comply with the front end shape of SUV’s, see Figure 8. Two SID-II
dummies are used in the front and rear seats on the vehicle struck side. No child dummies are used in the
IIHS side impact test.

Figure 8 — Test configuration in IIHS side impact test [IIHS, 2005]
3.3 Japanese side impact test method
In Japan, ECE Regulation No. 95 (see above) is used for compulsory side impact tests. J-NCAP utilises Euro-
NCAP side impact test method (see above) with some changes. The most important within this context are:
⎯ Test speed is 55 km/h;
⎯ No child dummies are prescribed.
3.4 Australian side impact test method
The compulsory side impact test for cars in Australia is defined by ADR72, which is equal to ECE Regulation
No. 95 (as described above). The Australian consumer test programme (ANCAP) follows in most parts the
protocols of Euro-NCAP (see above). However, no child dummies are tested in the rear seat.
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ISO/TR 14646:2007(E)
4 Child related properties of car side impact test methods
4.1 Boundary conditions for a CRS side impact test procedure
In several full-scale crash tests according to regulation ECE Regulation No. 95 performed in the last ten years,
dynamic lateral intrusions of front and rear doors were measured. The sample includes super minis, family
cars, executive cars and mini multi-purpose vehicles of the model years from 1990 until 2004. Both two-door
and four-door cars are included. In the last tests the revised deformable barrier face according to
EEVC/WG 13 was used. In all test the lateral intrusion of the inner part of the doors was measured with a
string potentiometer or a cross tube positioned at the middle of the door. Intrusion velocities (4.3) were
calculated from the intrusion time history diagrams. For comparison, car-to-car test results are analysed in 4.4.
4.2 Door intrusion depth
The maximum intrusion depth of the front door varies from 180 mm to 310 mm, whereas the newer vehicles
have lower intrusions (Figure 9).

Figure 9 — Front door intrusion depth in side impact tests according to ECE Regulation No. 95
[Johannsen, 2005]
It can be seen that the maximum intrusion depth of the rear door varies from 170 mm to 280 mm, which
indicates that the intrusion depth is lower at the rear door compared with the front door (Figure 10).
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ISO/TR 14646:2007(E)

Figure 10 — Rear door intrusion depth in side impact tests according to ECE Regulation No. 95
4.3 Door intrusion velocity from ECE tests
Regarding the intrusion velocity a comparable result can be observed. The intrusion velocity is again lower at
the rear door compared with the front door.

Figure 11 — Front door intrusion velocity in side impact tests according to ECE Regulation No. 95
[Johannsen, 2005]
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intrusion depth [mm]

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ISO/TR 14646:2007(E)
The intrusion velocity at the front door shows a range between 8 m/s and 13 m/s (Figure 11), while the
intrusion velocity at the rear door varies between 7 m/s and 13 m/s (Figure 12).

Figure 12 — Rear door intrusion velocity in side impact tests according to ECE Regulation No. 95
Taking into account the difficulties in positioning of the intrusion measurement device especially in smaller
cars, a mean difference in intrusion velocity between front and rear door of 10 % can be observed (Figure 13).
The difference could be caused either by vehicle design or the test procedure with the centre of impact
located more in the front.
10
front door rear door
10 %
8
6
4
2
0
car 1 car 2 car 3 car 4 car 5 car 6 average

Figure 13 — Comparison of maximum intrusion velocity for front and rear seat
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v[m/s]
intrusion velocity [m/s]

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ISO/TR 14646:2007(E)
4.4 Door intrusion velocity in car-to-car tests
For the development and assessment of a new European side impact test procedure several car-to-car and
MDB-to-car side impact tests were conducted on behalf of EEVC/WG13 [Ellway, 2005]. These data help to
analyse real-world side impact accidents, as passenger cars were used as the striking vehicles.
The intrusion measurement data presented below are acquired by acceleration based measurements for the
Camry tests (except the AEMDB V2 test) and the Corolla car-to-car tests. For the other tests string potentio-
meters were used. The intrusion was measured close to the position of the thoraxes of driver and rear seat
passenger but without interferences. When comparing acceleration based and string potentiometer based
intrusion measurements, Ellway came to the conclusion that the first one tends to deliver higher residual
velocity towards the end of the impact.
Figure 14 shows front door intrusion velocity of the inner door panel of an Alfa Romeo 147 running at 24 km/h
which was struck by a Toyota Corolla travelling at 48 km/h. In a second test an Alfa Romeo 147 was struck by
a Land Rover Freelander. While intrusion velocity in the Toyota test was approximately 6,5 m/s, the
Land Rover Freelander caused an intrusion velocity of more than 12 m/s.

Figure 14 — Comparison of front door intrusion velocity in car-to-car and SUV-to-car test [Ellway,
2005]
Looking at the rear door intrusion velocity of the inner panel these recorded approximately 7,5 m/s in the
Corolla test compared to 10,5 m/s in the Land Rover Freelander test, see Figure 15.
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Figure 15 — Comparison of rear door intrusion velocity in car-to-car and SUV-to-car test [Ellway, 2005]
Tests with a Toyota Camry, an executive saloon, showed again considerable differences between car-to-car
(in this case a Ford Mondeo was used) and SUV-to-car tests. The intrusion velocities at the front door were
approximately 5 m/s for the Mondeo and 9,5 m/s for the Freelander respectively, see Figure 16. For the rear
door the intrusion velocities varied between 7 m/s (in the Ford test) and 10,5 m/s (in the Land Rover test, see
Figure 17).

Figure 16 — Comparison of front door intrusion velocity in different side impact tests with a Toyota
Camry [Ellway, 2005]
The MDB tests were carried out utilising a barrier face stiffness and geometry (increased ground clearance)
different from that of ECE Regulation No. 95. In addition the sled mass was increased to 1 500 kg. These
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ISO/TR 14646:2007(E)
measures should help to represent a more realistic accident severity. The IIHS tests were in accordance to
the test procedure described in 3.2.3 above.

Figure 17 — Comparison of rear door intrusion velocity in different side impact tests with a Toyota
Camry [Ellway, 2005]

Figure 18 — Comparison of front door intrusion velocity in different side impact tests with a Toyota
Corolla [Ellway, 2005]
In the tests with a Toyota Corolla considerable differences between front and rear door are visible, see
Figure 18 and Figure 19. While the intrusion velocity in the Corolla-to-Corolla test were relatively low for the
front seat (approx. 3,5 m/s compared with 6 m/s at the rear door) this was contrary to the situation for all other
tests.
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ISO/TR 14646:2007(E)

Figure 19 — Comparison of rear door intrusion velocity in different side impact tests with a Toyota
Corolla [Ellway, 2005]
4.5 Struck car acceleration and velocity change
In addition to the intrusion of the side structure the struck car experiences a lateral acceleration.
00.000000 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045 0.050 0.055 0.060 0.065 0.070 0.075 0.080 0.085 0.090 0.095 0.100
time [s]

Figure 20 — Acceleration of the struck car in ECE Regulation No. 95 tests [Nett, 2003]
© ISO 2007 – All rights reserved 13

acceleration [g]
-50.0 -45.0 -40.0 -35.0 -30.0 -25.0 -20.0 -15.0 -10.0 -5.0 0.0.00 5.0 10.0

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ISO/TR 14646:2007(E)
Taking into account the theoretical velocity change for cars of an average weight in ECE Regulation No. 95
tests the struck car will be accelerated up to 22 km/h (Figure 20), which is in line with the derived velocity
change from the vehicle acceleration time histories shown in Figure 21.
time [s]
0.0.0000 0.01 0.01 0.02 0.02 0.03 0.03 0.04 0.04 0.05 0.05 0.06 0.06 0.07 0.07 0.08 0.08 0.09 0.09 0.10 0.10
time [s]

Figure 21 — Velocity change of the struck car in ECE Regulation No. 95 tests [Nett, 2003]
4.6 Deformation profiles
The comparison of static deformation of the struck vehicle from front to rear shows at first an increasing crush
over a distance of about 500 mm, then a more or less constant crush over a distance of about 900 mm and
then a decreasing trend (Figure 22).

Figure 22 — Static crush of different cars in ECE Regulation No. 95 tests [Johannsen, 2005]
The static crush in the EEVC/WG13 as described above show a comparable static crush as mentioned above,
see Figure 23 and Figure 24. The crush distribution across the vehicle height shows significant differences.
Again the influence of properties of the striking vehicle can be observed.
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crush [mm]
velocity [km/h]
-50.0 -45.0 -40.0 -35.0 -30.0 -25.0 -20.0 -15.0 -10.0 -5.0 0.00.0 5.0 10.0 15.0

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Row A

Figure 23 — Static crush of Alfa 147 in several side impact tests [Ellway, 2005]

Row A
Figure 24 — Static crush of Toyota Corolla in several side impact tests [Ellway, 2005]
4.7 Dynamic force-deflection characteristics of door interior
In addition to the dynamic behaviour, the geometric boundary condition of passenger cars, such as the lateral
distance between seat and side structure, the height of the window sill in relation to the CR-point, and the
stiffness of the side structure, are important.
The stiffness of the door trim, analysed in pendulum tests, showed considerable differences for different car
models and different impact locations, see Figure 25.
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Figure 25 — Door trim force-deflection characteristics of different locations at different doors
[Nett, 2003]
4.8 Door window sill height and distance to door trim
Investigation of Nett [Nett, 2003] showed a lateral distance of the CRS centreline to the side structure of
300 mm and a window sill height of 500 mm.
The average window sill height with respect to the CR point is approximately 500 mm [Nett, 2003], Figure 26.
window sill right rear door
500
400
300
200
100
0
0 50 100 150 200 250 300 350 400 450
distance to CR point [mm] in x direction

Figure 26 — Height of the window sill in different cars [Nett, 2003]
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force [N]

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ISO/TR 14646:2007(E)
The CRS centreline has an average distance to the inner door trim of approximately 300 mm [Nett, 2003],
Figure 27.
minimum distance between seat centre line and door trim right rear
car type
12 345 678 9 10 11 12 13 14 15
0
100
200
300
400
500

Figure 27 — Lateral distance between CRS centreline and inner door trim [Nett, 2003]
5 Requirements for the side impact test procedure
The requirements of the ISO side impact test procedure for child restraint systems can be divided into the
sections; test severity, validation, repeatability and reproducibili
...