Global Technical Regulation No. 7
|Name:||Global Technical Regulation No. 7|
|Official Title:||UN Global Technical Regulation on Head Restraints.|
|Country:||ECE - United Nations|
|Date of Issue:||2008-03-13|
|Amendment Level:||Amendment 1 of January 18, 2021|
|Number of Pages:||112|
|Vehicle Types:||Bus, Car, Component, Heavy Truck, Light Truck|
|Subject Categories:||Occupant Protection|
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head, restraint, seat, position, test, height, dummy, backset, restraints, back, annex, torso, vehicle, rear, angle, paragraph, regulation, requirements, gtr, procedure, injury, dynamic, whiplash, adjustment, biorid, front, measurement, seating, seats, iwg, injuries, h-point, point, line, meeting, neck, measured, positions, design, grsp, reference, reported, acceleration, united, proposal, adjustable, r-point, manufacturer, machine, occupant
All InterRegs documents are formatted as PDF files and contain the full text, tables, diagrams and illustrations of the original as issued by the national government authority. We do not re-word, summarise, cut or interpret the regulatory documents. They are consolidated, published in English, and updated on a regular basis. The following text extract indicates the scope of the document, but does not represent the actual PDF content.
January 18, 2021
Created on November 18, 2004, Pursuant to Article 6 of the
AGREEMENT CONCERNING THE ESTABLISHING OF GLOBAL TECHNICAL
REGULATIONS FOR WHEELED VEHICLES, EQUIPMENT AND PARTS WHICH
CAN BE FITTED AND/OR BE USED ON WHEELED VEHICLES
(ECE/TRANS/132 and Corr.1)
DONE AT GENEVA ON JUNE 25, 1998
UN GLOBAL TECHNICAL REGULATION NO. 07
(ESTABLISHED IN THE GLOBAL REGISTRY ON MARCH 13, 2008)
Amendment 1 dated January 18, 2021
Height measurement test procedure
Minimum width measurement test procedure
GAP measurement test procedure
Backset measurement test procedure using the R-Point method
Displacement, backset retention, and strength test procedure
Energy absorption test procedure
Height retention test procedure
Dynamic performance test procedure
Non-use position test procedure
Three-dimensional reference system
Procedure for validation of the H-Point and R-Point relationship for seating positions in
Description of the three-dimensional H-Point machine
2. UNDERSTANDING WHIPLASH
4. Although whiplash injuries can occur in any kind of crash, an occupant's chances of
sustaining this type of injury are greatest in rear-end collisions. When a vehicle is struck
from behind, typically several things occur in quick succession to an occupant of that
vehicle. First, from the occupant's frame of reference, the back of the seat moves forward
into his or her torso, straightening the spine and forcing the head to rise vertically. Second,
as the seat pushes the occupant's body forward, the unrestrained head tends to lag behind.
This causes the neck to change shape, first taking on an S-shape and then bending
backward. Third, the forces on the neck accelerate the head, which catches up with � and,
depending on the seat back stiffness and if the occupant is using a shoulder belt, passes �
the restrained torso. This motion of the head and neck, which is like the lash of a whip, gives
the resulting neck injuries their popular name.
3. CURRENT KNOWLEDGE
5. There are many hypotheses as to the mechanisms of whiplash injuries. Despite a lack of
consensus with respect to whiplash injury biomechanics, there is research indicating that
reduced backset will result in reduced risk of whiplash injury. For example, one study of
Volvo vehicles reported that, when vehicle occupants involved in rear crashes had their
heads against the head restraint (an equivalent to 0mm backset) during impact, no whiplash
injury occurred. By contrast, another study showed significant increase in injury and
duration of symptoms when occupant's head was more than 100mm away from the head
restraint at the time of the rear impact.
6. In addition, the persistence of whiplash injuries in the current fleet of vehicles indicates that
the existing height is not sufficient to prevent excessive movement of the head and neck
relative to the torso for some people. Specifically, the head restraints do not effectively limit
rearward movement of the head of a person at least as tall as the average occupant.
Biomechanically, head restraints that reach at least up to the centre of gravity of the head
would better prevent whiplash injuries, because the head restraint can more effectively limit
the movement of the head and neck.
7. In a recent report from the Insurance Institute for Highway Safety (IIHS), Farmer, Wells, and
Lund examined automobile insurance claims to determine the rates of neck injuries in rear
end crashes for vehicles with the improved geometric fit of head restraints (reduced backset
and increased head restraint height). Their data indicate that these improved head
restraints are reducing the risk of whiplash injury. Specifically, there was an 18% reduction
in injury claims. Similarly, United States of America computer generated models have
shown that the reduction of the backset and an increase in the height of the head restraint
reduces the level of neck loading and relative head-to-torso motion that may be related to
the incidence of whiplash injuries.
13. It was proposed that the gtr, as it pertains to front outboard seats, should apply to vehicles
up to 4,536kg. The United States of America presented justification (HR-4-4), developed in
1989, when the applicability of their Regulation was increased to 4,536kg. By extending the
applicability from passenger cars to include trucks, buses, and multipurpose passenger
vehicles, there was an estimated reduction of 510 to 870 injuries at an average cost of
$29.45 per vehicle (1989 dollars). The United States of America presented further analysis
(HR-10-3) that showed an additional 348 injuries reduced when the requirements of the gtr
are applied to Category 2 vehicles (light trucks) between the range of 3,500 � 4,500kg GVM.
Japan presented 2004 data (HR-4-10) showing the breakdown, by vehicle weight, of
crashes resulting in whiplash injuries. They show 7,173 (2.3%) rear impacts involving
vehicles with a GVM over 3,500kg that resulted in bodily injury.
14. There is consensus to recommend a wide application in the gtr. Specifically, that head
restraints in all front outboard seating positions for Category 1-1 vehicles, for
Category 1-2 vehicles with a gross vehicle mass of up to 4,500kg, and for Category 2
vehicles with a gross vehicle mass up to 4,500kg.
15. Given the variability in target population in different jurisdictions, such as the differing data
from the United States of America and Japan, it was recommended that the gtr should be
drafted to have a wide application to vehicles, to maximize the ability of jurisdictions to
effectively address regional differences in whiplash crash characteristics. The gtr would
establish that if a jurisdiction determines that its domestic regulatory scheme is such that full
applicability is inappropriate, it may limit domestic regulation to certain vehicle categories or
mass limits. The jurisdiction could also decide to phase-in the requirements for certain
vehicles. A footnote was added to the gtr text to make it clear that jurisdictions can decide to
limit the applicability of the Regulation. This approach recognizes that niche vehicles that
are unique to a jurisdiction would best be addressed by that jurisdiction, without affecting the
ability or need for other jurisdictions to regulate the vehicles. When a Contracting Party
proposes to adopt the gtr into its domestic regulations, it is expected that the Contracting
Party will provide reasonable justification concerning the limitation of the application of the
16. The informal group was unable to define a purpose that correlated with injury since the
mechanisms are not well understood. Therefore, more general text was developed from the
definition of head restraints. The recommended text for the purpose is: "This gtr specifies
requirements for head restraints to reduce the frequency and severity of injuries caused by
rearward displacement of the head."
19. Ideally, the degree of whiplash injury should be evaluated based on dynamic testing that
represents "real world" crashes; that is, based on a vehicle acceleration that occurs in real
crashes and a dummy with high biofidelity that reflects the injury mechanism, and injury
indices. However, at present, there is still not a sufficient amount of medical data to
accurately define the injury mechanism; therefore appropriate injury indices have not been
developed. In the interim, AC.3 recommends a dynamic testing option, as an alternative to
the static performance requirements in this gtr. A dynamic test option was proposed
primarily for two reasons. First, a dynamic test better represents "real-world" injury-causing
events and thus is expected to produce greater assurance than the static measurement
option of effective real world performance.
Second, as explained below, it is believed that a dynamic test will help to encourage
continued development and use of "dynamic" head restraint systems because the test is
designed to allow a manufacturer the flexibility necessary to offer innovative dynamic head
20. Dynamic head restraint systems deploy in the event of a collision to minimize the potential
for whiplash. During the normal vehicle operation, the dynamic head restraint system is
"retracted." Because a dynamic head restraint system requires a certain range of motion to
work effectively, an "undeployed" dynamic head restraint system might not meet the static
performance requirements, in particular the backset measurement requirements.
21. Although the dynamic compliance option is intended to ensure that the gtr encourages
continuing development of dynamic head restraint systems, the option is left to the
manufacturer and is available to both dynamic and conventional, or "static," head restraint
systems. That is, both types of head restraints can be evaluated to either static
requirements or the dynamic test option.
22. The United States of America currently has the only regulation with a dynamic testing
option. Under the United States of America dynamic option, the entire vehicle is exposed to
a half-sine deceleration pulse with a target of 8.8g peak and 88ms duration. The
50th percentile male Hybrid III dummy in each seat must have a maximum head-to-torso
rotation of less than 12° and a HIC15 (Head Injury Criteria) of less than 500.
23. In this gtr under direction from AC.3, when the dynamic test procedure with Hybrid III is
allowed the maximum relative head-to-torso rotation value is limited to 12° with the
50th percentile male dummy in all seats, with the head restraint adjusted vertically midway
between the lowest and the highest position of adjustment. The head restraint is to be
positioned at the middle position of vertical adjustment because there are concerns with the
effects of this gtr on dynamic head restraint systems. As previously stated, there is a need
to ensure that the dynamic test option encourages continuing development of dynamic head
restraint systems. As discussed below, research indicates that current head restraint
systems can meet the head-to-torso rotation limit in this gtr when the head restraint is
adjusted midway between the lowest and the highest position of adjustment.
26. The United States of America performed sled testing as specified in the dynamic
compliance option on a specially designed seat to explore how various seat characteristics
affect relative head rotation and other dummy injury measures. An OEM seat with an
adjustable head restraint was modified by removing the original recliner mechanism and
replacing it with a pin joint free to rotate. The seat back was also reinforced with steel
channels that provided the attachment points for a spring and damper system on each side
of the seat. Seat back strength in the rearward direction was modified by changing the
springs and or their location of attachment relative to the hinge joint. In addition to seat back
strength, sensitivity analyses to head restraint attachment strength and seat back upholstery
compliance were also performed. Tests were performed with belted 5th percentile female,
50th percentile male and 95th percentile male Hybrid III dummies.
27. The head restraint height was either 750mm or 800mm and the backset was always 50mm
as measured by the HRMD. However, the majority of tests (20 tests) were performed with
the 50th percentile male dummy with a 750mm high head restraint. For all seat back
parameters tested with this configuration of dummy and head restraint height, the range of
relative head-to-torso rotation was 6 to 16°. HIC15 was measured for half of these tests and
ranged from 40 to 75. Nearly half of the seat configurations (9 of 20) met the 12° limit placed
on the dynamic compliance option for a head restraint in the lowest adjustment position
(750mm). In general, the smallest relative rotations were seen for the baseline seat back
strength and non-rotating seat backs irrespective of the other seat/head restraint
parameters. From these tests, it was concluded that the head rotation and HIC limits
selected can be met with typical seat back/head restraint designs when appropriate
consideration is given to design in terms of height, backset and strength of head restraint
28. In a separate set of tests, the United States of America subjected a MY 2000 Saab 9-3 seat
to the sled pulse of the dynamic test option. A 95th percentile male Hybrid III dummy
occupied the seat. The Saab 9-3 has a dynamic head restraint system, and the head
restraint was set to its highest position of adjustment. The maximum head-to-torso rotation
was 9�. Viano and Davidsson (Viano, D., Davidsson, J., "Neck Displacement of Volunteers,
BioRID P3 and Hybrid III in Rear Impacts: Implications to Whiplash Assessment by a Neck
Displacement Criterion (ND)," Traffic Injury Prevention, 3:1005-116, 2002) also sled tested a
9-3 head restraint at a slightly lower, 16km/h ∆V, with the seat occupied by a 50th percentile
male Hybrid III dummy. With the head restraint in the up position, the relative head rotation
was measured at 6.5°. With the head restraint midway between the lowest and the highest
position of adjustment, the relative head rotation was 10° at 23.5km/h ∆V. It is assumed that
this configuration would yield an even smaller head rotation at the 17.2km/h ∆V.
29. In summary, research indicates that the head-to-torso rotation limit of 12° will not discourage
the development of dynamic head restraint systems. Current systems, such as the one in
2000 Saab 9-3 and the Toyota Whiplash Injury Lessening (WIL) seat (measured 6° of
rotation), can meet the head-to-torso rotation limit in this gtr. The United States of America
testing has also shown that current static head restraints/seats need more extensive
modification to meet the head-to-torso rotation limits. These changes might include
increasing the strength of attachment to the seat for adjustable head restraints and
optimization of the seat back upholstery for compliance.
32. The specified sled pulse is representative of one experienced in a crash when the head
restraint is needed to provide protection. The appropriateness of the ∆V and average
acceleration of the pulse is supported by a 2002 Swedish study by Krafft and others
(Krafft, M., Kullgren, A., Ydenius, A., and Tingvall, C. (2002) Influence of Crash Pulse
Characteristics on Whiplash Associated Disorders in Rear Impacts � Crash Recording in
Real-Life Impacts, Traffic Injury Prevention, Vol. 3 (2), pp 141-149). This study examined
rear impact crashes with crash recorders where the crash pulse was known (66 such
crashes). It examined the relationship between whiplash injury risk and parameters such as
∆V, peak acceleration, average acceleration, and average windowed acceleration for 18ms,
36ms, and 80ms. It found that the mean acceleration best correlated with whiplash injury
risk. For most occupants who had whiplash symptoms for longer than a month, the mean
acceleration of the crash pulse was greater than 4.5g and above a ∆V of 15km/h. For this
group, the mean acceleration was 5.3g and the average ∆V was 20km/h. The crash pulse
has a 5.6g mean acceleration and 17.3km/h ∆V. The EEVC have published a review of the
latest information available concerning rear impact pulses and their relationship to whiplash
and associated disorders (Recommendations for a Low Speed Rear Impact Sled Test
Pulse, EEVC, September 2007, http://www.eevc.org). The report was not able to
recommend a single specific pulse shape correlating to injury, instead proposing either a
bimodal or triangular, with a ΔV of 20km/h and mean acceleration of 5-6g to address
longer-term (symptoms greater than one month duration). Therefore, it is believed that the
sensors should be designed to activate the head restraint in such a situation. There is
concern that if a trigger point is specified, i.e., specified that the head restraint be activated
at a specific point in time as part of the test procedure, there would be no test of the sensors
and no assurance that the head restraint would activate during the type of crash simulated
by the sled pulse. At this time, GRSP does not recommend including a trigger point.
33. Research indicates that currently available dynamic head restraints can meet the
requirements of this option for the gtr. Given that the informal group strongly encourages the
development of a future fully developed alternative dynamic test procedure, including
dummy recommendations and criteria for evaluating whiplash injuries, that would further
encourage innovative dynamic head restraint designs, further discussion concerning
revision of the current dynamic option was suspended. Notwithstanding that an alternative
dynamic test, incorporating BioRID II, may be introduced into this gtr, it is expected that
research to develop a single dynamic test would supersede efforts to revise the Hybrid III
dynamic option. However, if future information led to different conclusions than those used
to develop the existing procedure and criteria (such as the trigger point or head-to-torso
angle rotation), amendments could be made to this option.
Seat Set Up and Measuring Procedure for Static Requirements
41. There were two proposals under discussions concerning the set-up of the seat for the
measurement of height and backset. One proposal is to use the manufacturer's
recommended seating position as detailed in UNECE Regulation No. 17. The other is to use
the procedure that is outlined in the recently adopted United States of America FMVSS
No. 202, which positions the seat in the highest position of adjustment and sets the seat
back angle at a fixed 25°. GRSP recommends that the seat be measured at the
manufacturer's design position to allow additional flexibility to account for vehicles with very
upright seat back design angles.
42. It was argued that there are several vehicle concepts (e.g., light trucks, minivans, SUV's and
full size vans) in which a seat back angle of 25° is not realistic nor feasible, thus leading to a
much larger backset using United States of America's procedure as compared to the real
world situation. It was stated that SAE J-1100 July 2002 recommends a 22° nominal torso
43. Also, it was stated that 5th percentile female stature occupants do not sit at 25° torso
angles, but prefer about 18° and some as little as 14. It argued that this more upright back
angle greatly reduces the backset to the point it interferes with the head of some of these
occupants, not just the hair.
44. After considering the arguments, the informal group believes the flexibility of using the
design seat back angle is appropriate. Additional flexibility is needed to account for vehicles
with very upright design angles. As a practical matter, this approach provides some
additional backset flexibility for most seats, since the typical design seat back angle is 23.5°.
Specifying that such a seat be tested at the design seat back angle instead of 25° is roughly
equivalent to increasing the backset limit by 4.5 to 6mm. Therefore, this helps address
possible concerns related to comfort.
45. It was also noted that while the Head Restraint Measurement Device (HRMD) was designed
to be used at 25°, the device has an articulation to allow for adjustment of the head for
varying torso angles. The device can therefore be used at different seat back angles. It is
relatively rare that a seat can be adjusted to have a seatback angle of exactly 25°. Thus,
even prior to the change to specify seat back angle, the standard specified testing in the
adjustment position closest to 25°. For these reasons, there should be no problem in testing
vehicles at the design seatback angle.
50. Both UNECE Regulation No. 17 and the FMVSS No. 202 Final Rule require front outboard
head restraints with a minimum height of 800mm above the R-Point/H-Point, respectively. A
proposal was made to recommend a minimum height of 850mm, to accommodate the taller
citizens of some countries. Using recent anthropometric research (see HR-3-6 and
HR-4-16) it was demonstrated that when considering erect sitting height a 95th percentile
Netherlands male needs a head restraint height of 849mm to give protection equivalent to
that of the average occupant. The UK submitted data (HR-4-14 and HR-6-11) showing their
population is tall enough to need taller head restraints. The UK also provided an EEVC Cost
Benefit Analysis (UK Cost Benefit Analysis: Enhanced Geometric Requirements for Vehicle
Head Restraints, European Enhanced Vehicle-safety Committee (EEVC), September 2007,
http://www.eevc.org) demonstrating benefits for increasing head restraint height above
51. There are concerns with raising the height of the head restraint above 800mm at this time. It
was noted that with an 800mm head restraint, it is starting to become a challenge for
manufacturers to be able to install seats in the vehicle, and a larger head restraint can also
restrict occupant visibility (blocking vision rearward and to the side) (see HR-3-5). Additional
data was presented (see HR-3-4) that showed that in small cars, 850mm head restraints
could severely restrict rearward vision in the rearview mirror.
52. Additionally, there are concerns that the method in which the height is measured may not
reflect the effective height that would be needed to address the safety concerns of taller
occupants. There have been some proposals put forth to improve the measurement
method, but they were not yet fully developed for inclusion in the gtr. (See Section 5.6.4. for
further discussion of this measurement method.)
53. At this time, AC.3 has directed that the height requirement be limited to 800mm, but
recommends that the discussion on increasing the height requirement and/or revising the
measurement method be continued in Phase 2 to this gtr.
Front Centre and Rear Head Restraints
a. Defining a Front Centre and Rear Head Restraint
54. This gtr provides an objective definition and a test procedure for determining the presence
of a head restraint. A vehicle seat will be considered to have a head restraint if the seatback
or any independently adjustable seat component attached to or adjacent to the front centre
or rear seat back, that has a height equal to or greater than 700mm, in any position of
backset and height adjustment.
60. After considering the reduction in safety benefits and a review of the fleet, it was determined
that the clearance exemption is not needed for front or rear seats for folding positions and
therefore it is recommended that an exemption of 25mm only be applied in cases of
interference with the interior roofline (headliner) or backlight. An exemption of 50mm for
convertible roofs is also recommended to account for the articulation of the folding top
Adjustable Front Head Restraints � Front Contact Surface Area
61. It was initially proposed to include in the gtr the UNECE Regulation No. 17 requirement that
the height of the head restraint face be a minimum of 100mm to ensure sufficient surface for
the occupant's head to contact. The UNECE Regulation No. 17 requirement is measured in
the same manner as the overall height of the head restraint. There have been concerns
expressed that the measurement taken in this manner does not address the effective height
of the restraint. In the case of extremely contoured head restraints, the height of the surface
that the head would contact is less than the measured height. This is demonstrated in
Ineffective Part of the Head Restraint
68. The consensus within the biomechanics community is that the backset dimension has an
important influence on forces applied to the neck and the length of time a person is disabled
by an injury. As early as 1967, Mertz and Patrick first showed that reducing the initial
separation between the head restraint and head minimizes loading on the head during a
rear impact. More recently, the Olsson study, which examined neck injuries in rear end
collisions and the correlation between the severity of injuries and vehicle parameters,
showed that the duration of neck symptoms was correlated to the head restraint backset.
Specifically, reduced backset, coupled with greater head restraint height, results in lower
injury severity and shorter duration of symptoms.
69. A different study examined sled tests to determine the influence of seat back and head
restraint properties on head-neck motion in rear impacts. The study concluded that the head
restraint backset had the largest influence on the head-neck motion among all the seat
properties examined. With a smaller backset, the rearward head motion was stopped earlier
by the head restraint, resulting in a smaller head to torso displacement. The findings
indicated that a reduction in backset from 100mm to 40mm would result in a significant
reduction in whiplash injury risk.
70. A study conducted by Eichberger examined real world rear crashes and sled tests with
human volunteers to determine whiplash injury risk and vehicle design parameters that
influence this risk. The study found a positive correlation between head restraint backset
and head to torso rotation of the volunteers and to the reported whiplash injury complaints.
The most important design parameters were a low horizontal distance between the head
and head restraint as well as the head restraint height.
71. A study conducted by Dr. Allan Tencer, PhD, used rigid occupant body models enhanced
with finite element models of the cervical spine for simulating rear impacts in order to
examine the effect of backset on neck kinematics and forces and moments in the neck. The
study concluded larger backset correlates to greater displacement between cervical
vertebrae and shearing at the facet capsules that are likely associated with whiplash injury.
With the head initially closer to the head restraint, the time difference between the
occurrences of the peak upper and lower neck shear forces are smaller. At 50mm backset
and lower, the head moved more in phase with the torso and extension of the head was
reduced indicating a lower risk of whiplash injury. IIHS, in its studies of head restraints,
considers a backset of 70mm or less to be "good".
77. GRSP recommends that it is necessary that the H-Point manikin and HRMD machine are
considered as a single tool and that they must therefore be calibrated together and remain
as a matched pair for use in regulatory assessments. However, GRSP has noted that at this
time there is no agreed calibration procedure or generally available calibration equipment to
ensure compliance with this recommendation. This poses significant risk with respect to
reproducibility. It therefore recommends that, a suitable calibration procedure and
equipment be incorporated into regulations that use type approval as a method for approval.
78. Transport Canada conducted a study to verify whether the HRMD is an adequate tool to
measure backset. Among other things, the study sought to verify specifications and
dimensional tolerances of the HRMD headform and measuring probes. Transport Canada
reported that the headform is manufactured to have a mass of 3,150 ± 50g, and all linear
dimensions of the headform are within ±0.25mm of the drawing specifications for the
headform size "J" provided in ISO DIS 6220 � Headforms for use in the testing of protective
helmets. It also reported that both height and backset probes are within ±2mm of the RONA
Kinetics drawing specifications, and that conformity with the drawing specifications is
accomplished with the specially designed "jig". Dimensional drawings for this headform
have been provided in the Annex to this gtr.
79. The HRMD is a purely mechanical device. Also, unlike a crash dummy, it is not subjected to
crash test forces. The informal group notes that the International Insurance Whiplash
Prevention Group (IIWPG), of which ICBC is a member, has identified that variability
between three-dimensional manikins can be an issue when using the ICBC HRMD. To
address this issue, IIWPG has developed a "Gloria jig" to calibrate the combination together
as one single unit. The Working Group understands that the Gloria jig (or its specification)
will not be available commercially, but rather will be used by a commercial enterprise to offer
a calibration service. For this reason the Working Group cannot specify its use as part of
this gtr. Therefore, although no detailed calibration procedure is included in the gtr text, the
group recommends that such procedure is developed.
80. In a study conducted by the United States of America (HR-5-4), variation in backset
measurements when using multiple laboratories was examined. This study concluded,
among other things, that taking the average of three backset measurements at each of three
labs reduced the average measurement range between the labs by about half (from 8.5mm
to 4.5mm). Using an average of three measurements in each of backset position of
adjustment, at a 2 standard deviation (s.d.) (97.7%) level of certainty, the expected
variability was 5.64mm; at a 3 s.d. (99.9%) level of certainty, the expected variability was
8.47mm. Data were presented by Japan showing a variability of up to 29mm (HR-7-10).
Data was presented by International Organization of Motor Vehicle Manufacturers (OICA)
showing a variability of up to 11mm. (GRSP-41-22)
81. The Transport Canada study, which used eight vehicles, sought to verify whether the HRMD
is an adequate tool to measure backset. It concluded that the HRMD provides repeatable
and reproducible results after calibration. It also found that increasing the number of
measurements always reduced the backset measurement variability. Using an arithmetic
mean of the three measurements in each backset position of adjustment, at a 2 s.d. (97.7%)
level of certainty, the expected variability was 2.6mm; at a 3 s.d. (99.9%) level of certainty,
the expected variability was 3.9mm.
Backset Limit and Comfort
86. When the United States of America benefit analysis for regulating height and backset was
examined, it was noted that all the benefits for the front seat passengers come from
regulating the backset. These benefits are achieved by improving the current situation. The
United States of America proposed a backset limit of 55mm measured at manufacturer's
design seat back angle and measured with the HRMD, using the H-Point as the initial
reference. Others proposed a less stringent backset of 70mm.
87. The EEVC Cost Benefit Analysis (UK Cost Benefit Analysis: Enhanced Geometric
Requirements for Vehicle Head Restraints, EEVC, September 2007, http://www.eevc.org)
considered the potential costs and benefits of introducing a backset limit of between 40 and
100mm. Benefits were determined by the evaluation of potential casualty savings that might
occur as a result of a regulatory change with the cost to industry consistent based on the
US data. The study used UK data and proposed that significant savings could be achieved
through changes to existing head restraint geometry (including the introduction of a backset
requirement, Figure 3.
Potential Long-term Whiplash Injury Savings in the
UK through Increased Height and Backset Requirements
Head Restraint Height Adjustment Retention Devices (Locks)
93. GRSP recommends that performance requirements for adjustable head restraints be
included in the gtr which are intended to assure that the front head restraints remain locked
in specific positions. A 1982 United States of America NHTSA study (HR-3-13) found that
the effectiveness of integral head restraints was greater than adjustable head restraints. The
study concluded that this difference in effectiveness was due, in part, to adjustable head
restraints not being properly positioned. Although one reason for improper positioning is a
lack of understanding on the part of the occupant on where to place the head restraint, it
also could be due to the head restraint's moving out of position either during normal vehicle
use or in a crash. Adjustment locks can mitigate this problem by helping to retain the
adjusted position. IIHS has also been critical of adjustable head restraints, especially when
they do not provide locks, in their evaluation of head restraints. This criticism has
manifested itself in that IIHS, in its rating of head restraints, automatically gave adjustable
restraints a lower rating on the assumption that these restraints would not be properly
adjusted. In addition, it only evaluated adjustable head restraints without locks in their
lowest position. The United States of America has received comments during its regulatory
process to update its head restraint regulation from consumer groups and vehicle
manufacturers supporting adjustable head restraints that lock.
94. The proposed requirements of this gtr are expected to improve the performance of all
adjustable head restraints. The performance of adjustable head restraints may be further
improved if steps are taken to ensure that a restraint remains in position after it has been set
by the user.
95. Therefore, GRSP is recommending that adjustable head restraints for the front outboard
seating positions must maintain their height (i.e., lock) in several height positions under
application of a downward force. In addition to locking at a position of not less than 800mm,
they must also lock at the highest adjustment positions. It may be that, for some designs,
the highest position is at 800mm. Adjustable head restraints for the front centre and rear
outboard seating positions must lock at the highest position of adjustment above 750mm, if
this position exists. In addition to locking at these specified positions of height adjustment,
both front centre and rear outboard head restraints must be capable of retaining the
minimum height of 750mm under application of a downward force. Adjustable head
restraints for rear centre seating positions must lock at the highest position of adjustment
above 700mm and be capable of retaining the minimum height of 700mm under the
application of a downward force.
96. The proposed height adjustment retention lock test begins by applying a small initial load to
the head restraint. A headform is used to apply the load and a reference position is
recorded. The reference position is measured with this load applied to eliminate variability
associated with the soft upholstery of the head restraint. A 500N load is then applied
through the headform to test the locking mechanism. Finally, the load is then reduced to the
initial value and the headform is checked against its initial position. In order to comply, the
locking and limiter mechanisms must not have allowed the headform to have moved more
than 25mm from the initial reference position.
Front Outboard Seats
101. The informal group believed it was important to balance the need to ensure that the head
restraint is in the proper position while maintaining the functionality of the seat. In some
current designs the head restraint can be placed in a non-use position when the vehicle seat
is folded down to increase the cargo capacity of the vehicle. It has been proposed to allow
non-use positions in the front outboard seats, as long as they automatically return to the
proper position when the seat is occupied. GRSP is recommending a test procedure using
the 5th percentile female Hybrid III dummy or a human surrogate to evaluate these systems.
Front Centre and Rear Seats
a. Manually Adjusted Non-use Positions
102. It is recommended to regulate of non-use positions in the rear seats, as long as the position
is "clearly recognizable to the occupant". There is discussion on how to objectively evaluate
this requirement. One proposal is to define "clearly recognizable" as a head restraint that
rotates a minimum of 60° forward or aft. There was concern that this definition is too design
restrictive as the sole method and additional methods have been proposed (HR-4-13).
103. The United States of America developed a human factors study to determine if an occupant
would be likely to reposition their head restraint as a function of the torso angle change the
head restraint produced in the non-use position (HR-5-23). The baseline seat for this study
was the second row captain's chair of a 2005 model year Dodge Grand Caravan. In its
original equipment manufacturer configuration, the seat created a nominal 5° torso angle
change between its non-use and in-use positions. The head restraint was then modified by
introducing two forward offsets that generated either a 10 or 15° torso angle change. One
other condition that was used was to attach a label to the head restraint in the 5° condition.
The label was modified from a label used by Volvo.
104. Of the participants who adjusted the head restraint, 88% adjusted it immediately after sitting
down. The 5° condition and label condition were unsuccessful in motivating participants to
adjust the head restraint. For the 5° condition, only 3 out of 20 participants (15%) adjusted
the head restraint. None of the participants (0 out of 20) adjusted the head restraint as a
result of the label. The 10° condition had a nearly 80% success rate, 19 out of 24. Only four
participants were run in the 15° condition since the percentage of participants who adjusted
the head restraint in the 10° condition was high. The 15° condition had a 100% rate of
adjustment. Based on the results of this study, GRSP agreed to recommend the 10° torso
angle change option as an alternative.
105. Some experts and participants support the use of labels since these head restraints are
optional, and a label in a non-use position is better than no label at all. Additionally, the need
for labels was suggested because the use of the torso angle change method or discomfort
metric may be incompatible with the installation of child restraints. Some experts do not
support the use of labels, because there are already too many labels in the vehicles and,
based on the United States of America study, the labels were ineffective in causing the
occupant to move the head restraint out of the non-use position, although 50% of those
questioned understood what the label meant, and an additional 30% understood that the
head restraint was adjustable. To accommodate all views in the gtr, labels will be
recommended as an optional method to be accepted by the Contracting Party. Based on the
available data, Contracting Parties can choose the level of risk they are comfortable with.
111. GRSP is recommending an energy absorption requirement specifying that when the front of
the head restraint is impacted by a headform the deceleration of the headform must not
exceed 80g continuously for more than 3ms. This recommendation is different from the
current United States of America and UNECE Regulations in that it does not specify a type
of impactor, but rather a required energy. This would allow either the linear impactor, the
free motion impactor, or the pendulum impactor to be used for testing. Studies showed that
the results of the test were similar regardless of what type of impactor was used (HR-4-8,
Radius of Curvature
112. The informal group discussed incorporating the UNECE Regulation No. 17 requirement that
designated parts of the front of the head restraint shall not exhibit areas with a radius of
curvature less than 5mm pre- and post-test. There was concern that a breakage could occur
during the test which would produce a sharp edge. This sharp edge could harm occupants
in a secondary impact. The informal group was unable to agree on a test procedure and
therefore the requirement was not included in the gtr at this time. Due to these concerns,
some Contracting Parties may wish to continue regulating for radius of curvature under their
current regulation scheme.
Displacement Test Procedures/Adjustable Backset Locking Test/Ultimate Strength
113. GRSP is recommending the incorporation of requirements to evaluate the head restraint's
ability to resist deflection and significant loading. The displacement test requires that a head
restraint cannot deflect more than 102mm when a 373Nm moment is applied to the seat.
Additionally, the seat system must not fail when an 890N load is applied to the seat and
maintained for 5s.
114. Additionally, GRSP is recommending, based on Contracting Party determination, that head
restraints with adjustable backset maintain their position while under load. Some strongly
believe that if an occupant adjusts his head restraint backset so that it is less than the
requirement, then he should have some assurance that it will maintain that position when
loaded. Some further believe, that this requirement should only apply to required head
restraints and not those optionally installed. Others strongly believed that the safety needs
are met at the requirement. Therefore the gtr was drafted so that a Contracting Party can
designate whether adjustable head restraints will be tested at all positions of backset and to
which head restraints this will apply. The test for adjustable head restraints incorporates
both the evaluation for total displacement of the head restraint and the evaluation of the
locking mechanism for the adjustable backset.
8. REVIEW OF EXISTING INTERNATIONAL REGULATIONS
120. The following existing Regulations, Directives, and Standards pertain to head restraints:
UNECE Regulation No. 17 � Uniform provisions concerning the approval of vehicles
with regard to the seats, their anchorages, and any head restraints.
UNECE Regulation No. 25 � Uniform provisions concerning the approval of head
restraints (Head Rests), whether or not incorporated in vehicle seats.
European Union Directive 74/408/EEC (consolidated), relating to motor vehicles with
regard to the seats, their anchorages and head restraints.
European Union Directive 78/932/EEC.
(e) European Union Directive 96/03/EC, adapting to technical progress
Council Directive 74/408/EEC relating to the interior fittings of motor vehicles
(strength of seats and of their anchorages).
United States of America Code of Federal Regulations Title 49: Transportation;
Part 571.202: Head Restraints.
Australian Design Rule 3/00, Seats and Seat Anchorages.
Australian Design Rule 22/00, Head Restraints.
Japan Safety Regulation for Road Vehicles Article 22 � Seat.
Japan Safety Regulation for Road Vehicles Article 22-4 � Head Restraints, etc.
Canada Motor Vehicle Safety Regulation No. 202 � Head Restraints.
International Voluntary Standards -SAE J211/1 revised March 1995 � Instrumentation
for Impact Test � Part 1 � Electronic.
Korea Safety Regulation for Road Vehicles Article 99 � Head Restraints.
121. Additionally, research and activities being conducted by European Enhanced Vehicle Safety
Committee (EEVC) Working Group 12, EEVC Working Group 20, EuroNCAP, and Korea
NCAP were also considered.
128. The dynamic evaluations of seats in addressing minor neck injuries (Maximum Abbreviated
Injury Scale 1 – MAIS 1) that occur in low-speed rear impact crashes were conducted by
insurance groups (i.e. International Insurance Whiplash Prevention Group (IIWPG),
Insurance Institute for Highway Safety (IIHS) and Thatcham). The European New Car
Assessment Programme (Euro NCAP) and the Korean New Car Assessment Program
(KNCAP) introduced dynamic evaluations of seats in 2008; the Japanese New Car
Assessment Programme (JNCAP) in 2009, and the China New Car Assessment
Programme in 2012. However, the testing and evaluation methods varied from one
programme to another. Additionally, the European Enhanced Vehicle-safety Committee
(EEVC) Working Group 12 had investigated the appropriate dynamic test for addressing
minor injuries in low-speed crashes. This included the test procedure, injury criteria and the
associated corridors for the BioRID II dummy.
129. An in-depth review of a first set of data from the expert of the United States of America
showed that while a number of AIS 2 and AIS 3 injuries occur in rear impact crashes at
speeds greater than 18km/h, most of the neck injuries (which are the focus of this UN GTR
and which can be evaluated with a rear impact dummy) are AIS 1. AIS 1 injuries occur in
approximately equal numbers below or above 18km/h. Research from the expert of Japan
showed similar results, with a significant number of long-term minor neck injuries occurring
130. An evaluation of research by EEVC, "Recommendations for a Low-speed Rear Impact Sled
Test Pulse", concluded that most long-term minor neck injuries (greater than one month) are
sustained at speeds between 16 and 25km/h. The expert from the United States of America
evaluated several dummies in addressing long-term minor neck injuries and compared them
to cadaver testing at 24km/h.
131. Although previous research differentiated between "low speed" and " all the research was
conducted at speeds which could be considered as "low speed" for short-term and
long-term minor neck injuries. As a complement to speed tests, the IWG developed a
comprehensive approach to determining the most appropriate test pulse(s) to mitigate minor
neck injuries. This resulted in a level of injury benefit comparable to the requirements of UN
GTR No. 7. IWG also identified options which provided additional benefits focusing on
long-term injuries during the time frame of the work schedule these could be promoted but
this work should not delay the principal task.
132. At the 153rd session of the World Forum, the representatives of Japan, the United Kingdom
and the United States of America jointly submitted a proposal to amend the Terms of
Reference (ToR) so that the dynamic evaluation method under study could focus on
reducing injuries from low-speed rear impact crashes. The aim was to finalize the draft
amendments to the UN GTR for recommendation at the December 2012 session of GRSP
and for establishment at the June 2013 session of AC.3. The amendment proposal for ToR
133. At the 154th session of the World Forum, a delay was reported in the injury criteria work of
the experts of Japan and the United States of America that would hinder the satisfactory
conclusion of the work. In addition, the representative of the United States of America
questioned whether the dummy drawing package and other specifications would not be
better incorporated into a separate UN GTR. The development of a Mutual Resolution No. 1
(M.R.1) between the 1958 and 1998 Agreements was decided upon and submitted to
WP.29 for discussion.
140. At the 170th session of WP.29, the representative of Japan reported on the work progress
of IWG. Since the IWG meeting in September 2015, studies on PMHS by NHTSA had not
been sufficient to provide data to enable the establishment of suitable injury criteria. The
IWG was waiting for further study results on PMHS to be conducted by NHTSA, which were
expected by spring 2017. He clarified that these results might help the full incorporation of
BioRID into the UN GTR and avoid the adoption of empirical values. He advised that the
IWG would provide an update on the progress of work at the March 2017 session of AC.3 to
seek consent for a revised timetable for the delivery of the proposed amendment to UN
GTR No. 7.
141. At the 171st session of WP.29, the Chair of the IWG on UN GTR No.7, Phase 2 reminded
WP.29 that the work to establish injury criteria, based on biomechanical data, had been
inconclusive and that the work of the group had now been suspended for approximately
18 months. It appeared that new data would not be available before the end of 2017 and
that a different approach might be necessary. AC.3 extended the mandate of the IWG until
142. At the 172nd session of WP.29, the representative of the United Kingdom on behalf of the
Chair of IWG, reported that IWG had been unable to establish injury criteria directly from
PMHS testing but that they had developed some understanding based on empirical data. He
added that the expert from the United States of America had agreed to explore their ability
to provide further PMHS data, but it seemed likely that they would not be able to complete
any related work before the end of 2017. Accordingly, AC.3 agreed to extend the time
mandate for IWG to allow finalization of its work. by using an empirical approach if the data
could not be obtained.
143. At the 175th session of WP.29, the Chair of the IWG on Phase 2 of UN GTR No. 7 on head
restraints, informed WP.29 that IWG had not been able to establish a correlation between
PMHS and BioRID responses. Developing injury criteria directly from PMHS testing required
still further research. However, he explained that the IWG intended to restart its activity to
submit an official proposal of amendments to the UN GTR based on empirical data at the
December 2018 session of GRSP. The proposed amendments would also be introduced as
a revision to UN Regulation No.17. The amendments would be presented as:
An informal document to introduce the latest development of the IWG on injury
The final status report of the IWG, and
A proposal of Addendum 1 to the M.R.1 to incorporate drawings and specifications of
He expected finalization of this work within one year of activity and therefore requested an
extension of the mandate. AC.3 agreed to the extension of the mandate until June 2019.
144. At the 176th session of WP.29, the representative of Japan, as technical sponsor, reported
on the progress of work. He recalled that at the 175th session of WP.29 the Chair of the
IWG had informed AC.3 of his intention to restart activity. He recalled that a working
document on UN GTR No.7, phase 2 activity had been submitted to the 64th session of
GRSP. He explained that GRSP had discussed the remaining items and that the IWG would
consider the remaining points in square brackets in preparation for the 65th session of
GRSP session in May 2019.
150. The original draft UN GTR No. 7 contained a proposal addressing these concerns, but a
final decision was not reached. In response to statements that the back-of-head is
dependent on the occupant's height, the expert from the Dutch Organization for Applied
Scientific Research (TNO) presented a study (GTR7-04-03). Therein, the automotive
posture study from UMTRI-83-53-1 (used to create the Head Restraint Measurement Device
(HMRD) concept) was combined with the anthropometric database of the Civilian American
and European Surface Anthropometry Resource (CAESAR). It was found that in this
posture (UMTRI design torso angle) the back-of-head of the CAESAR 2004 NL large male
is 39mm more rearward than an HRMD occupant. In comparison, the UMTRI-86-39 study
showed a 31mm difference in the back-of-head position between the mid-size male and a
large male from the 1980s. Thus, it could be concluded that the effective height (in Figure 2
indicated for HRMD-occupant) for this CAESAR 2004 NL large male is reached at a bigger
backset comprising the HRMD backset plus Distance x (here 39mm). To calculate this
"Distance x" for any design torso angle, the principle of the Torso and Neck Link (shown in
Annex 5 of UN GTR No. 7, Phase 1) is supplemented with an up-scaled Torso and Neck
Link representing the CAESAR 2004 NL large male. The resulting calculations are
presented as a table expressing the difference in back-of-head position (in direction X)
between the mid-sized male (HRMD) and the large male (CEASAR NL 2004 male) at
various torso angles and this is defined as Distance x. The test procedure for an effective
head restraint height was reduced to merely goniometric measurements (excluding
non-biofidelic interactions) and contained simply five steps (GTR7-08-03).
155. At the eighth IWG meeting, the expert from the Netherlands presented the proposed
effective height measurement method with a proposal of text of the regulation. Annex 1
described the determination of the highest head restraint height at Paragraph 2.3.3. as
"2.3.3. Determination of the Highest Head Restraint Height."
The head restraint height is the distance from the R-point, parallel to the torso
reference line and limited by a line perpendicular to the torso reference line
intersecting IP. After the coordinates of IP are determined, the highest head
restraint height can be calculated by its longitudinal (ΔX) and vertical (ΔZ)
distance from the R-point, as follows:
Head restraint height = ΔX ∙ SIN (design torso angle) + ΔZ ∙ COS (design torso
IWG discussed the proposed method of head restraint height measurement and noted some
issues remaining concerning certain head restraint shapes and the measurement device.
The task force considered these issues and the IWG discussed them further at the following
156. At the 51st GRSP session, the expert from the Netherlands introduced a proposal to
increase head restraint height (GRSP-51-24). The expert from OICA stated that the
discussion should focus first on the definition of the measurement method and then on the
height thresholds. GRSP agreed to resume discussion at its December 2012 session on the
basis of a possible proposal of draft UN GTR No. 7, Phase 2 that may be submitted by IWG.
157. At the workshop held in the middle of March 2013 at Federal Highway Research Institute
(BAST), effective head restraint height measurement procedure was examined by using an
actual vehicle. The workshop finding are in Annex 1 of this UN GTR. The workshop also
concluded that the backset can be measured without HRMD.
158. At the 53rd GRSP meeting, the expert from the Netherlands proposed head restraint height
requirements (GRSP-53-15) and GRSP resumed discussion at its December 2013 session
on the draft proposal submitted by the experts from the Germany, the Netherlands and the
159. At the 54th GRSP meeting, the expert from the United States of America questioned
(GRSP-54-23) the rational for both proposed height values. The expert from OICA observed
(GRSP-54-18-Rev.1) that the new measurement procedure would reduce the measured
height. GRSP agreed to resume consideration on this agenda item on the basis of a final
proposal of draft amendment submitted by the IWG and of further justification
164. At the fourth IWG meeting, the expert from NHTSA reported on the
repeatability/reproducibility and biofidelity research. NHTSA had conducted dynamic tests at
17.6 and 24km/h. NHTSA also conducted tests comparing PMHS with Hybrid III, BioRID,
and RID3D. The dummies showed different biofidelity in head displacement and rotation
during tests for reproducibility, repeatability and biofidelity. The ramping-up behaviour was
quite different between PMHS and dummies. The evaluation of biofidelity and repeatability
were planned for completion by the end of October and December of 2010 respectively.
NHTSA had also conducted tests to compare sensitivity and reproducibility among
dummies. They compared the results using BioRID II and Hybrid III in seats with large and
small backsets and waveforms as specified in FMVSS 202a and in a UN Regulation No. 17
proposal to incorporate a BioRID (Annex 9) to evaluate if the tests rank the severity of
backset in the same manner. The testing was planned to be completed by November 2010
and the results to be presented in February 2011. OICA requested that a biofidelity
assessment be conducted on the rear impact dummy chosen for this UN GTR, over the
range of potential seatback angles.
165. One of the original tasks of the informal group was to develop a low-speed dynamic test,
including the test procedure, compliance criteria and the associated corridors for the
biofidelic rear impact dummy (BioRID II). As a possible later phase, depending upon the
direction of WP.29, the group would consider the possibility of a higher-speed dynamic test.
166. At the fourth meeting, the Chair recalled that IWG was tasked to report to WP.29 at its
152nd session (November 2010), and specifically, to confirm the timetable for delivering a
proposal for adopting the BioRID II dummy into UN GTR No. 7. He suggested
recommending to WP.29 that the period for consideration of Phase 2 would be
approximately two years, that the adoption by GRSP be in December 2012, that a proposal
to WP.29 be in June 2013. The recommendation was based on the completion, as
scheduled, of the research that was being conducted by the experts from Japan and the
United States of America by the end of 2011, and moreover, on successfully establishing
injury criteria suitable for evaluation in a regulatory test procedure.
167. Japan commented that BioRID II be added to the UN GTR in May 2011 as specified in the
original ToR, since neck injury was a serious problem that needed to be addressed in the
regulation immediately. Two options were proposed:
Option 1: A proposal to amend UN GTR No. 7 that would be submitted to GRSP in
May 2011 to specify dynamic backset evaluations using either Hybrid III or BioRID II,
as a Contracting Party option. Then, as a second step, harmonization of the dummy,
evaluation of upright postures, tests at higher speed and at mid-speed to be
considered in 2014 and later.
Option 2: Extend the work schedule of the informal group to require a proposal to
amend UN GTR No. 7 to be submitted to GRSP in December 2012, in anticipation
that a harmonized dynamic backset evaluation proposal would be made based on the
injury criteria using BioRID II only. Then, as a second step, harmonization of the
dummy, evaluation of upright postures, tests at higher speed and at mid-speed to be
considered in 2014 and later.
168. OICA expressed strong concerns that both of these options would result in a UN GTR of
choice by the Contracting Parties.
177. By the fourth IWG meeting, Humanetics (a company formed by the merger of Denton and
FTSS), had had the drawings posted on the GRSP website. They reported that 3D data was
ready, but that the Procedures for Assembly, Disassembly, and Inspection (PADI) was
under revision. They announced the preparation of the list, to be included in PADI, for
checking the most recent dummy. The Chair of IWG pointed out that a method to clarify the
suitability of the build level of BioRID II was needed. A suggestion from the expert of Japan
to provide PADI along with drawings in a same website was agreed on.
178. At the 153rd session of WP.29, the Chair of IWG introduced a proposal for a protocol to
manage drawings, manuals and specifications under WP.29 responsibilities. The basic
principle was agreed on.
179. At the eighth IWG meeting, the Chair reported the status of the register of technical
specifications. It was noted that WP.29 had decided, as a first step, that data had to be
incorporated into the Consolidated Resolution on the Construction of Vehicles (R.E.3). The
amendment to R.E.3 would also be used for other ATDs.
180. At the 158th session of WP.29, the World Forum and AC.3 adopted the Mutual Resolution
No. 1 (M.R.1) of the 1958 and the 1998 Agreements which concerns the description and
performance of test tools and devices.
181. At the 14th IWG meeting, PDB reported on that the dummy drawing check was almost
ready for incorporation into addendum 1. (M.R.1).
182. At the 178th session of WP.29, the representative from the United Kingdom, explained that
a proposal to amend M.R.1 would incorporate drawings and specifications of the Biofidelic
Rear Impact Dummy. However, he indicated that the major challenge was the legal issue of
copyright infringement concerning the above-mentioned specifications and consequent
limitation of their public usage. He concluded by announcing that work would continue in
close cooperation with the secretariat and with the dummy manufacturer to devise a
disclaimer text, that would be removed from the drawings once the amendment was
adopted by WP.29 and AC.3.
183. At the 18th TEG meeting in August 2019, Humanetics stated that ECE was allowed to use
the drawings and the PADI of the BioRID for rulemaking purposes within the framework of
184. At the "meeting of interested experts", the history of discussions on the new certification test
at GBUM and the summary of those discussions were presented. The new certification test
procedure was completed in Japan, the Republic of Korea, the United States of America
and the European Union. The resulting sled waveform had become flatter, showing good
reproducibility. At the second IWG meeting, it was proposed to change the calibration
waveform to match that of the Euro NCAP medium pulse and dummy input. However, the
Chair commented that since the ToR of the informal group states that our objective is to
specify the uniform method for evaluating low-speed impacts, and that the low speed is
defined as V18km/h or below, we should aim for a sled waveform around 16–18km/h and
discuss the calibration waveform based on the current proposal (GBUM2009).
192. At the 18th informal meeting in April 2019, Humanetics reported on the dummy certification
work, and particularly, about a halt in the work on the "Gen-X" test. Humanetics
recommended, instead of the “Gen-X” test, a regular replacement of all bumpers throughout
the dummy to cover bumper change/ageing over time and the additional pelvis and jacket
test. The test descriptions will be in the documentation of the addendum to M.R.1 on BioRID
193. At the seventeenth TEG meeting in May 2019 held by Webex, Humanetics explained the
simplicity and the advantages of the parts replacement management method over the
"Gen-X" test. The properties of the bumpers are checked by a special compression test.
Humanetics also informed TEG about some stakeholder's concerns on the POT-A
certification test corridor. They invited test data to be provided for POT-A corridor
corrections. The Chair of TEG suggested data collection by mid-June 2019 and progress
confirmation at the next TEG meeting.
194. At the 18th TEG meeting in August 2019, Humanetics reported on an analysis of
certification data from 89 different dummies. The data comprised 1,164 tests from
6 laboratories in an aim to review the certification test corridor, especially POT-A. However,
TEG could only make final conclusions during the meeting. The Chair of TEG asked
Humanetics for an updated analysis for the nineteenth meeting.
195. At the 19th TEG meeting in September 2019, Humanetics presented the results of an
updated analysis. Members of the TEG discussed the corridors and proposed only minimal
and appropriate changes. Therefore, the Chair of TEG concluded that all certification
corridors should be maintained as they are in the current manual with the exception of Pot A
To adjust Pot A corridor at mean and keep the same corridor width;
Keep jacket and pelvis compression for monitoring purposes only. (no pass/fail
Review all certification criteria after 3 years;
Remove C4 accelerometer mount.
Repeatability and Reproducibility
196. In testing, good repeatability was obtained if the same dummy was used. However, there
were problems with reproducibility among different dummies. Work to establish a common
build level for BioRID II, together with dummy improvements and revised certification tests
were being discussed to improve their repeatability and reproducibility.
197. At the third meeting, Japan reported on the results of the new dummy calibration methods
and sled tests. The same variations in Lower Fz that had been seen in the new certification
test method with the simulated head restraint were also observed in the sled tests.
Accordingly, it was considered effective to use the head restraint in the certification test,
especially to minimize variations around the contact time. However, there were differences
in absolute values between certification and sled tests, and so further discussed in
202. At the 11th informal meeting, Humanetics reported on the sled test results of the refurbished
dummies. The results indicated better reproducibility with CV values but still needed data
analysis. The TEG Chair proposed an additional sled test series with European Commission
(EC) project rig seat and PDB hard bucket seat. The test results were discussed at the
subsequent IWG meeting in mid-February 2013.
203. At the BioRID TEG and IWG meeting, Chrysler reported the repeatability and reproducibility
analysis from the EC project of dummy repeatability and reproducibility, which showed that
some channels are good and some poor. The dummy components, jacket, pelvis and
bumper had since been updated through validation tests and the analysis showed the
dummy reproducibility had been improved (Series 1, Series 2).
204. At the 15th IWG meeting, Humanetics reported on the status of development update for the
dummy certification test and the reproducibility issue. Humanetics reported that the stiffness
of the candidate replacement materials for the spine bumper (Urethane rubber) in BioRID
had proven unstable with ageing. He confirmed that all current testing proceeded by using
matched and stable material and that new materials, when available, would be
benchmarked against the original.
205. At the IWG meeting by WebEX in mid-November 2014, Humanetics reported that the
dummy quality had improved as a result of the new procedures. Repeatability,
reproducibility and CV values were reported for several dummies. Matched dummies were
identified for delivery to NHTSA (VRTC).
206. At the 16th informal meeting, NHTSA provided positive data for the repeatability and
reproducibility of BioRID based on their latest sled test series.
207. At the 17th TEG meeting by Webex, Humanetics spoke about the investigation of R&R by
the bumper compression force test. Japan agreed to provide the bumper for this
investigation data. Humanetics would report on the conclusion of the R&R by the bumper
compression force test at the next TEG meeting.
208. At the 18th TEG meeting, Japan showed research on the influence of the hardness of
ARA-220 bumpers to Pot A corridor. At the 19th TEG meeting, Humanetics spoke about the
addition of the bumper compression values to the bumper drawings.
Dummy Seating Conditions
209. At the "meeting of interested experts" and at the first informal meeting on the seating
procedures of IIWPG and EuroNCAP, Japan made proposals on:
Design reference torso angle;
Reduction of backset tolerance; and
Special adjustment in the case of smaller torso angle (more upright) seats typically
used in small N vehicles (especially those with forward control).
And explained the reasons for the proposals (GTR7-01-09e).
219. The neck damper was damaged during the new calibration test procedures in the Republic
of Korea. Ford pointed out that it was necessary to add a body block to the calibration sled
to prevent damage to dummies.
220. At the fourth IWG group meeting, it was agreed that the issue experienced by the Republic
of Korea had not been seen elsewhere and it was not considered to be a problem.
221. BioRID tests exhibited good repeatability in a number of studies. However, problems were
identified in reproducibility among different dummies. The generic build level according to
commercial identification did not adequately specify the tool and a specific build level was
established: BioRID II, along with dummy improvements.
222. European Commission research showed that differences in the measured values from
different BioRID ATD could be associated with the torso flesh, i.e. when swapping the flesh
between ATD the resulting values changed accordingly. The research also recommended
an evaluation of the contribution of BioRID’s intervertebral bumpers.
223. The spine curvature of BioRID was established using a former (comb) during its assembly.
This curvature essentially determines the device's posture. IWG had based its evaluation
work on the most recumbent of the two defined build options as this covers the majority of
vehicle seats in the market.
224. While evaluation had not been made of the recumbent device's repeatability and
reproducibility when used in very upright vehicle seats, certain limitations were recognised
even in a static condition, e.g. the stability of the head.
225. The use of BioRID was therefore limited, in the context of this UN GTR, for use with seat
back angles between 20° and 30°.
226. The repeatability and reproducibility studies were completed exclusively using acceleration
sleds (those that are accelerated from rest by the application of a sudden force). Annex 9 of
this UN GTR contains procedures for the BioRID dummy using an acceleration sled only.
Backset Measurement Method
227. The current H-point machine is defined in Society of Automotive Engineers (SAE)
SAE J826, and the HRMD was developed in the 1990s. For either machine, variations are
large in the products available on the market, resulting in variations in the backset
228. At the second informal meeting, the results of research conducted by the German
manufacturer's association (VDA) were introduced. VDA had developed a new H-point
machine and a testing jig "Dilemma" by taking the average of many H-point machines and
harmonizing it with the SAE standard. The VDA specifications were scheduled for issue in
February 2010 and then a revision to the standard would be proposed to SAE.
TEXT OF THE REGULATION
This Regulation specifies requirements for head restraints to reduce the frequency and
severity of injuries caused by rearward displacement of the head.
This Regulation applies to all Category 1-1 vehicles; Category 1-2 vehicles with a Gross
Vehicle Mass of up to 4,500kg; and Category 2 vehicles with a Gross Vehicle Mass of up
3.1. "Adjustable head restraint" means a head restraint that is capable of movement
independent of the seatback between at least two positions of adjustment intended for
3.2. "Backlight" means rearward-facing window glazing located at the rear of the roof panel.
3.3. "Backset" means the horizontal distance between the front surface of the head restraint
and the rearmost point of the head.
3.3.1. "R-point Backset" means the backset as measured in accordance with Annex 4.
3.3.2. "BioRID Reference Backset" means the backset as determined in accordance with
3.4. "Head restraint" means, at any designated seating position, a device that limits rearward
displacement of a seated occupant's head relative to the occupant's torso and that has a
height equal to or greater than 700mm at any point between two vertical longitudinal
planes passing at 85mm on either side of the torso line, in any position of backset and
height adjustment, as measured in accordance with Annex 1.
3.5. "Three-dimensional H-Point machine" (H-Point machine) means the device used for the
determination of "H-Points" and actual torso angles. This device is defined in Annex 12.
3.6. "Head restraint height" means the distance from the R-Point, measured parallel to the
torso line to the effective top (IP) of the head restraint on a plane normal to the torso line.
3.7. "Intended for occupant use" means, when used in reference to the adjustment of a seat
and head restraint, adjustment positions used by seated occupants while the vehicle is in
motion, and not those intended solely for the purpose of allowing ease of ingress and
egress of occupants; access to cargo storage areas; and or storage of cargo in the
4. GENERAL REQUIREMENTS
4.1. Whenever a range of measurements is specified, the head restraint shall meet the
requirement at any position of adjustment intended for occupant use.
4.2. In each vehicle subject to the requirements of this Regulation, a head restraint shall be
provided at each front outboard designated seating position, conforming to either
Paragraph 4.2.1. or Paragraph 4.2.2. at the choice of the manufacturer.
4.2.1. The head restraint shall conform to Paragraphs 5.1., 5.2., 5.4., and 5.5. of this Regulation.
4.2.2. The head restraint shall conform to Paragraphs 5.1.1. through 5.1.4., 5.3., 5.4., and 5.5. of
4.3. For vehicles equipped with rear outboard and/or front centre head restraints, the head
restraint shall conform to either Paragraph 4.3.1. or Paragraph 4.3.2. at the choice of the
4.3.1. The head restraint shall conform to Paragraphs 5.1.1. through 5.1.4., 5.2., 5.4., and 5.5. of
4.3.2. The head restraint shall conform to Paragraphs 5.1.1. through 5.1.4., 5.3., 5.4., and 5.5. of
4.4. For vehicles equipped with rear centre head restraints, the head restraint shall conform to
either Paragraph 4.4.1 or 4.4.2. at the choice of the manufacturer.
4.4.1. The head restraint shall conform to Paragraphs 5.1.2. through 5.1.4., 5.2., 5.4., and 5.5. of
4.4.2. The head restraint shall conform to Paragraphs 5.1.2. through 5.1.4., 5.3., 5.4., and 5.5. of
4.5. This Regulation does not apply to auxiliary seats such as temporary or folding jump seats
or to side-facing or rear-facing seats.
4.6. At designated seating positions incapable of seating the test dummy specified in
Paragraph 5.3. of this Regulation, the applicable head restraint shall conform to either
Paragraph 4.2.1., or 4.3.1, or 4.4.1. of this Regulation, as appropriate.
5.1.2. Minimum Width
When measured in accordance with Annex 2, the lateral width of a head restraint shall be
not less than 85mm on either side of the torso line (distances L and L').
5.1.3. Gaps within Head Restraint
If a head restraint has any gap greater than 60mm when measured in accordance with
Annex 3, the maximum rearward displacement of the head form shall be less than 102mm
when the head restraint is tested at that gap in accordance with Annex 5.
5.1.4. Gaps between Head Restraint and the Top of the Seat Back
When measured in accordance with Annex 3, there shall not be a gap greater than 60mm
between the bottom of the head restraint and the top of the seat back if the head restraint
can not be adjusted in height.
In the case of head restraints adjustable in height to more than one position intended for
occupant use, when measured in accordance with Annex 3, there shall not be a gap
greater than 25mm between the bottom of the head restraint and the top of the seat back,
with the head restraint adjusted to its lowest height position.
5.1.5. Backset Requirements
188.8.131.52. General Specifications
184.108.40.206.1. Head restraints on the front outboard designated seating positions shall meet the backset
requirements of Paragraph 220.127.116.11.
18.104.22.168. Static Maximum Backset Requirements
22.214.171.124.1. For height adjustable head restraints, the requirements shall be met with the effective top
of the head restraint in all height positions of adjustment between 720mm and 830mm ,
inclusive. If the effective top of the head restraint, in its lowest position of adjustment, is
above 830mm , the requirements of this Regulation shall be met at that position only.
For head restraints that are adjustable in the longitudinal plane of the vehicle, the
maximum backset requirement shall be achieved in any position of the available backset
126.96.36.199.2. When measured in accordance with Annex 4, the backset shall not be more than 45mm.
188.8.131.52.3. If the front outboard head restraint is not attached to the seat back, it shall not be possible
to adjust the seat or head restraint such that the backset is more than 45mm.
184.108.40.206.1. When the head restraint is tested in the rearmost (relative to the seat) position of
horizontal adjustment (if provided) in accordance with Annex 5, the head form shall not be
displaced more than 102mm perpendicularly and rearward of the displaced extended torso
line during the application of a 373Nm moment about the R-Point.
5.2.4. Head Restraint Strength
When the head restraint is tested in accordance with Annex 5, the load applied to the head
restraint shall reach 890N and remain at 890N for a period of 5s.
5.3. Dynamic Performance Requirements
5.3.1. Based on a determination by each Contracting Party or regional economic integration
organization, either a Hybrid III 50th percentile male dummy or a BioRID II
50th percentile male dummy shall be used to determine compliance. If a Hybrid III dummy
is used, the head restraint shall meet the requirements of Paragraph 5.3.2. If a BioRID II
dummy is used, the head restraint shall meet the requirements of Paragraph 5.3.3.
5.3.2. Hybrid III Requirements
220.127.116.11. When tested during forward acceleration of the dynamic test platform, in accordance with
Annex 8, at each designated seating position equipped with a head restraint, the head
restraint shall conform to Paragraphs 18.104.22.168 and 22.214.171.124.
126.96.36.199. Angular Rotation
Limit the maximum rearward angular rotation between the head and torso of the
50th percentile male Hybrid III test dummy to 12° for the dummy in all outboard designated
188.8.131.52. Head Injury Criteria
Limit the maximum HIC15 value to 500. HIC15 is calculated as follows: For any two points
in time, t and t , during the event which are separated by not more than a 15ms time
interval and where t is less than t , the head injury criterion (HIC15) is determined using
the resultant head acceleration at the centre of gravity of the dummy head, a , expressed
as a multiple of g (the acceleration of gravity) and is calculated using the expression:
HIC � �
5.4. Non-use Positions
5.4.1. A driver head restraint shall not have a non-use position.
5.4.2. A front outboard passenger head restraint may be adjusted to a position at which its height
does not comply with the requirements of Paragraph 184.108.40.206. of this Regulation. However,
in any such position, the front outboard passenger head restraint shall meet
Paragraph 220.127.116.11. of this Regulation.
5.4.3. All rear head restraints and any front centre head restraint may be adjusted to a position at
which their height does not comply with the requirements of either Paragraph 18.104.22.168.
or 22.214.171.124. of this Regulation. However, in any such position, the head restraint shall also
meet one additional requirement from a set of several alternative test requirements.
The set of alternative test requirements may be, at the choice of the manufacturer either
Paragraph 126.96.36.199., or 188.8.131.52., or 184.108.40.206. or 220.127.116.11. of this Regulation.
Based on a determination by each Contracting Party or regional economic integration
organization, the manufacturer may also be allowed to choose Paragraph 18.104.22.168. of this
Regulation as an alternative to Paragraphs 22.214.171.124. through 126.96.36.199.
5.4.4. Alternative Requirements
All of the items described in Paragraphs 188.8.131.52. to 184.108.40.206. are permitted.
220.127.116.11. In all designated seating positions equipped with head restraints, except the driver's
designated seating position, the head restraint shall automatically return from a non-use
position to a position in which its minimum height is not less than that specified in
Paragraph 5.1.1. of this Regulation when a 5th percentile female Hybrid III test dummy is
positioned in the seat in accordance with Annex 9. At the option of the manufacturer,
instead of using a 5th percentile female Hybrid III test dummy, human beings may be used
as specified in Annex 9.
18.104.22.168. In front centre and rear designated seating positions equipped with head restraints, the
head restraint shall, when tested in accordance with Annex 9, be capable of manually
rotating either forward or rearward by not less than 60° from any position of adjustment
intended for occupant use in which its minimum height is not less than that specified in
Paragraph 5.1.1. of this Regulation. A head restraint rotated by a minimum of 60° forward
or rearward, shall be considered to be placed in a non-use position even if the head
restraint height in such a position would be greater than that specified in Paragraph 5.1.1.
22.214.171.124. When measured in accordance with Annex 9, the lower edge of the head restraint (HLE)
shall be not more than 460mm, but not less than 250mm from the R-Point and the
thickness (S) shall not be less than 40mm.
126.96.36.199. When tested in accordance with Annex 9, the head restraint shall cause the actual torso
angle to be at least 10° less than when the head restraint is in any position of adjustment
in which its height is not less than that specified in Paragraph 5.1.1. of this Regulation.
HEIGHT MEASUREMENT TEST PROCEDURE
The purpose of this test procedure is to demonstrate compliance with the height requirements
described in Paragraph 5.1.1. of this Regulation.
2. PROCEDURE FOR HEIGHT MEASUREMENT
Compliance with the requirements of Paragraph 5.1.1. of this Regulation is demonstrated by
using the height measurement procedure defined in Paragraphs 2.2. and 2.3. below.
2.1. Relationship between the H-Point and the R-Point
The seat is adjusted such that its H-point coincides with the R-point; if the seat back is
adjustable, it shall be at the seat back inclination corresponding to the design torso angle; the
relationship between the H-point and the R-point shall be in accordance with the requirements
of Annex 4, Paragraph 2.2.1.
If, elsewhere during head restraint testing, the H-point and/or actual torso angle have not
been found in accordance with Annex 4, Paragraph 2.1.1. but consequently Paragraph 2.1.3.
or Paragraph 2.1.4. of Annex 4 have been applied, then the check on the relationship shall
not be repeated for the height measurement.
2.2. Height Measuring Apparatus
The height measurement shall be based on the use of an apparatus that facilitates the
measurement of coordinates.
2.3. Height Measurement
All measurements shall be taken in the median longitudinal plane of the designated seating
2.3.1. Determination of Contact Point (CP) (see Figure 1-1)
Adjust the head restraint to the position intended for use by the mid-sized male1, as specified
by the manufacturer. In the absence of any specification, the head restraint shall be adjusted
as close as possible to the mid-position. If two positions of adjustment are equidistant from
the mid-position, the head restraint shall be adjusted to the higher of the mid-position and/or
rear of the mid-position.
For head restraints not adjustable for height, the fixed position shall be used.
If there is only one in-use position, this shall be treated as a head restraint which is not
adjustable for height.
Head Position Table
Location of the back-of-head of two designated males in automotive posture with respect to the R-point
at several design torso angles, and their in-between "distance x"
calculated for the midsized
angle - 2.6)+71
calculated for the midsized
torso angle - 2.6)+203
calculated for large
angle - 2.6)+76
5 92 707 101 9
6 101 707 111 10
7 110 706 121 12
8 118 705 132 13
9 127 704 142 15
10 136 703 152 16
11 145 702 163 18
12 153 701 173 19
13 162 699 183 21
14 171 698 193 22
15 179 696 203 24
16 188 694 213 26
17 196 692 223 27
18 205 689 233 29
19 213 687 243 30
20 222 684 253 31
21 230 682 263 33
22 239 679 273 34
23 247 676 283 36
24 255 673 292 37
"Distance x": distance
back-of-head of both
88.5* sin(design torso
The H-point machine is shown to explain the concept but is not needed for this test procedure.
Goniometry in the Test Procedure Using Apparatus that Facilitate the Measurement of
GAP MEASUREMENT TEST PROCEDURE
The purpose of this test procedure is to evaluate any gaps within head restraints as well as
gaps between the bottom of the head restraint and the top of the seat back, in accordance with
the requirements of Paragraphs 5.1.3. and 5.1.4. of this Regulation.
Any gaps within the head restraint are measured using the sphere procedure described in
Paragraph 2. of this Annex.
Gaps between the bottom of the head restraint and the top of the seat back are measured
using either the sphere procedure described in Paragraphs 2.1. to 2.5. of this Annex, or, at the
manufacturer option, using the linear procedure described in Paragraph 3. of this Annex.
2. GAP MEASUREMENT USING A SPHERE
2.1. The seat is adjusted such that its H-Point coincides with the R-Point; if the seat back is
adjustable, it is set at the design seat back angle; both these adjustments are in accordance
with the requirements of Paragraph 2.1. of Annex 1.
2.2. The head restraint is adjusted to its lowest height position and any backset position intended
for occupant use.
2.3. The area of measurement is anywhere between two vertical longitudinal planes passing at
85mm on either side of the torso line and above the top of the seat back.
2.4. Applying a load of no more than 5N against the area of measurement specified in
Paragraph 2.3. above, place a 165 ± 2mm diameter spherical head form against any gap such
that at least two points of contact are made within the area.
2.5. Determine the gap dimension by measuring the straight line distance between the inner edges
of the two furthest contact points, as shown in Figures 3-1 and 3-2.
2.6. For gaps within the head restraint, if the measurement determined in Paragraph 2.5 of this
Annex exceeds 60mm, then in order to demonstrate compliance with the requirements of
Paragraph 5.1.3. of this Regulation, the seat back displacement test procedure described in
Annex 5 is performed, by applying to each gap, using a sphere of 165mm in diameter, a force
passing through the centre of gravity of the smallest of the sections of the gap, along
transversal planes parallel to the torso line, and reproducing a moment of 373Nm about the
3. LINEAR MEASUREMENT OF GAP
3.1. The seat is adjusted such that its H-Point coincides with the R-Point; if the seat back is
adjustable, it is set at the design seat back angle; both these adjustments are in accordance
with the requirements of Paragraph 2.1. of Annex 1.
3.2. The head restraint is adjusted to its lowest height position and any backset position intended
for occupant use.
3.3. The gap between the bottom of the head restraint and the top of the seat is measured as the
perpendicular distance between two parallel planes, described as follows (see Figure 3-3).
3.3.1. Each plane is perpendicular to the design torso line.
3.3.2. One of the planes is tangent to the bottom of the head restraint.
3.3.3. The other plane is tangent to the top of the seat back.
Measurement Gap Between Head Restraint and Top of the Seat Back
2.4. In the case of head restraint with adjustable backset, adjust the head restraint at the most
rearward position, such that the backset is in the maximum position.
2.5. Establish point D on the head restraint, point D being the intersection of a line drawn from
point C horizontally in the x-direction, with the front surface of the head restraint, see Figure 1-1
of Annex 1.
2.6. Measure the X-coordinate of point D. The R-point backset is the difference between the
X-coordinate of point D and the X-coordinate of the back-of-head of the mid-size male as given
in Table 1 of Annex 1.
2.4. Maintain the position of the back pan as established in Paragraph 2.3. of this Annex. Using a
165 ± 2mm diameter spherical head form, establish the head form initial reference position by
applying, perpendicular to the displaced torso line, a rearward initial load at the seat centreline at
a height 65 ± 3mm below the effective top of the head restraint that will produce a 373Nm
moment about the R-Point. After maintaining this moment for 5s, measure the rearward
displacement of the head form during the application of the load. In the case of simultaneous
testing of bench seats, the force shall be applied to all head restraints as present on the bench
2.5. When determining the rearward displacement for head restraints at a gap greater than 60mm in
accordance with Paragraph 5.1.3. of this Regulation, the load of Paragraph 2.4. of this Annex is
applied through the centre of gravity of the smallest of the sections of the gap, along transversal
planes parallel to the torso line.
2.6. If the presence of gaps prevents the application of the force, as described in Paragraph 2.4. of
this Annex at 65 ± 3mm from the top of the head restraint, the distance may be reduced so that
the axis of the force passes through the centre line of the frame element nearest to the gap.
3. PROCEDURES FOR BACKSET RETENTION AND DISPLACEMENT
3.1. If the seat back is adjustable, it is adjusted to a position specified by the vehicle manufacturer. If
there is more than one inclination position closest to the position specified by the manufacturer,
set the seat back inclination to the position closest to and rearward of the manufacturer specified
position. If the head restraint position is independent of the seat back inclination position,
compliance is determined at a seat back inclination position specified by the manufacturer.
Adjust the head restraint to the highest position of vertical adjustment intended for occupant use.
3.2. Adjust the head restraint to any backset position.
3.3. In the seat, place a test device having the back pan dimensions and torso line (vertical centre
line), when viewed laterally, with the head room probe in the full back position, of the
three-dimensional H-Point machine.
3.4. Establish the displaced torso line by creating a rearward moment of 373 ± 7.5Nm about the
R-Point by applying a force to the seat back through the back pan at the rate between 2.5Nm/s
and 3.7Nm/s. The initial location on the back pan of the moment generating force vector has a
height of 290mm ± 13mm. Apply the force vector normal to the torso line and maintain it within 2°
of a vertical plane parallel to the vehicle vertical longitudinal zero plane. Constrain the back pan
to rotate about the R-Point. Rotate the force vector direction with the back pan.
3.5. Maintain the position of the back pan as established in Paragraph 3.4. of this Annex. Using a
165 ± 2mm diameter spherical head form, establish the head form initial reference position by
applying, perpendicular to the displaced torso line, a rearward initial load at the seat centreline at
a height 65 ± 3mm below the effective top of the head restraint that will produce a 37Nm moment
about the R-Point. Measure the rearward displacement of the head form during the application of
3.6. If the presence of gaps prevents the application of the forces, as described in Paragraph 3.5. of
this Annex at 65 ± 3mm from the effective top of the head restraint, the distance may be reduced
so that the axis of the force passes through the centre line of the frame element nearest to the
ENERGY ABSORPTION TEST PROCEDURE
Evaluate the energy absorption ability of the head restraint by demonstrating compliance with
Paragraph 5.2.1. of this Regulation in accordance with this Annex.
2. SEAT SET-UP
The seat is either mounted in the vehicle or firmly secured to the test bench, as mounted in the
vehicle with the attachment parts provided by the manufacturer, so as to remain stationary when
the impact is applied. The seat-back, if adjustable, is locked in the design position specified by
the vehicle manufacturer. If the seat is fitted with a head restraint, the head restraint is mounted
on the seat-back as in the vehicle. Where the head restraint is separate, it is secured to the part
of the vehicle structure to which it is normally attached.
3. PROCEDURES FOR ENERGY ABSORPTION
The adjustable head restraints are measured in any height and backset position of adjustment.
3.1. Test Equipment
3.1.1. Use an impactor with a hemispherical head form of a 165 ± 2mm diameter. The head form and
associated base have a combined mass such that at a speed of not more than 24.1km/h at the
time of impact an energy of 152J will be reached.
3.1.2. Instrument the impactor with an acceleration sensing device whose output is recorded in a data
channel that conforms to the requirements for a 600Hz channel class filter as specified in
ISO Standard 6487 (2002). The axis of the acceleration-sensing device coincides with the
geometric center of the head form and the direction of impact. As an alternative the impactor can
be equipped with 2 accelerometers sensing in the direction of impact and placed symmetrically
in comparison to the geometric centre of the spherical head form. In this case the deceleration
rate is taken as the simultaneous average of the readings on the two accelerometers.
3.2. Accuracy of the Test Equipment
The recording instrument used is such that measurements can be made with the following
degrees of accuracy:
Accuracy: ±5% of the actual value;
Cross-axis sensitivity = < 5% of the lowest point on the scale.
Accuracy: ±2.5% of the actual value;
Sensitivity: = < 0.5km/h.
HEIGHT RETENTION TEST PROCEDURE
Demonstrate compliance with the height retention requirements of Paragraph 5.2.2. of this
Regulation in accordance with this Annex.
2. PROCEDURES FOR HEIGHT RETENTION
2.1. Seat Set-up
Adjust the adjustable head restraint so that its effective top is at any of the following height
positions at any backset position:
2.1.1. For front outboard designated seating positions:
188.8.131.52. The highest position; and
184.108.40.206. Not less than, but closest to 830mm
2.1.2. For rear outboard and front centre designated seating positions
220.127.116.11. The highest position; and
18.104.22.168. Not less than, but closest to 720mm.
2.1.3. For rear centre designated seating position
22.214.171.124. The highest position; and
126.96.36.199. Not less than, but closest to 700mm.
2.2. Orient a cylindrical test device having a 165 ± 2mm diameter in plane view (perpendicular to
the axis of revolution), and a 152mm length in profile (through the axis of revolution), such
that the axis of the revolution is horizontal and in the longitudinal vertical plane through the
vertical longitudinal zero plane of the head restraint. Position the midpoint of the bottom
surface of the cylinder in contact with the head restraint.
2.3. Establish an initial reference position by applying a vertical downward load of 50 ± 1N at a
rate of 250 ± 50N/min. Determine the reference position after 5s at this load. Mark an initial
reference position for the head restraint.
2.4. Measure the vertical distance between the lowest point on the underside of the head restraint
and the top of the seat back. (see Paragraph 2.9. of this Annex)
2.5. Increase the load at the rate of 250 ± 50N/min to at least 500N and maintain this load for not
less than 5s.
DYNAMIC PERFORMANCE TEST PROCEDURE
Demonstrate compliance with Paragraph 5.3. in accordance with this Annex, using a
50th percentile male Hybrid III or BioRID II (United Nations) test dummy.
2. TEST EQUIPMENT
2.1. An acceleration test sled.
2.2. 50th percentile male test dummy
2.2.1. Hybrid III
188.8.131.52. Three accelerometers are in the head cavity to measure orthogonal accelerations at the
centre of gravity of the head assembly. The three accelerometers are mounted in an
orthogonal array, and the intersection of the planes containing the sensitivity axis of the
three sensors will be the origin of the array.
184.108.40.206. Equipment for measuring the head to torso angle.
2.2.2. BioRID II
220.127.116.11. Conforming to Addendum 1 to the Mutual Resolution No. 1 (ECE/TRANS/WP.29/
18.104.22.168. Equipment for measuring and recording sled accelerations.
3. PROCEDURES FOR TEST SET-UP
3.1. Full Vehicle or Body in White (Hybrid III)
3.1.1. Mount the vehicle on a dynamic test platform so that the vertical longitudinal zero plane of
the vehicle is parallel to the direction of the test platform travel and so that movement
between the base of the vehicle and the test platform is prevented. Instrument the platform
with an accelerometer and data processing system. Position the accelerometer sensitive
axis parallel to the direction of test platform travel.
3.1.2. Remove the tires, wheels, fluids, and all unsecured components. Rigidly secure the engine,
transmission, axles, exhaust system, vehicle frame and any other vehicle component
necessary to assure that all points on the acceleration vs. time plot measured by an
accelerometer on the dynamic test platform fall within the corridor described in Figure 8-2
and Table 8-1.
3.1.3. Place any moveable windows in the fully open position.
3.1.7. Hybrid III Test Dummy Positioning Procedure
Place a test dummy at each designated seating position equipped with a head restraint.
The transverse instrumentation platform of the head is level within ½°. To level the head of
the test dummy, the following sequence is followed. First, adjust the position of the H-Point
to level the transverse instrumentation platform of the head of the test dummy. If the
transverse instrumentation platform of the head is still not level, then adjust the pelvic angle
of the test dummy. If the transverse instrumentation platform of the head is still not level,
then adjust the neck bracket of the dummy the minimum amount necessary from the
non-adjusted "0" setting to ensure that the transverse instrumentation platform of the head
is horizontal within ½°. The test dummy remains within the limits specified in footnote 1 of
this Annex after any adjustment of the neck bracket.
22.214.171.124. Upper Arms and Hands
Position each test dummy as specified below:
126.96.36.199.1. The driver's upper arms shall be adjacent to the torso with the centre lines as close to a
vertical plane as possible.
188.8.131.52.2. The passenger's upper arms are in contact with the seat back and the sides of the torso.
184.108.40.206.3. The palms of the driver's test dummy are in contact with the outer part of the steering wheel
rim at the rim's horizontal centre line. The thumbs are over the steering wheel rim and are
lightly taped to the steering wheel rim so that if the hand of the test dummy is pushed
upward by a force of not less than 0.91kg and not more than 2.27kg, the tape shall release
the hand from the steering wheel rim.
220.127.116.11.4. The palms of the passenger test dummy are in contact with the outside of the thigh. The
little finger is in contact with the seat cushion.
18.104.22.168. Upper Torso
Position each test dummy such that the upper torso rests against the seat back. The
midsagittal plane of the dummy is aligned within 15mm of the head restraint centreline. If the
midsagittal plane of the dummy cannot be aligned within 15mm of the head restraint
centreline then align the midsagittal plane of the dummy as close as possible to the head
22.214.171.124. Lower Torso
The H-Points of the driver and passenger test dummies shall coincide within 12.5mm in the
vertical dimension and 12.5mm in the horizontal dimension of a point 6.25mm below the
position of the H-Point determined by the manikin defined in Annex 11 and Annex 12.
126.96.36.199.2.2. Vehicles with Wheelhouse Projections in Passenger Compartment
Place the right and left feet in the well of the floor pan/toeboard and not on the wheelhouse
projection. If the feet cannot be placed flat on the toeboard, initially set them perpendicular
to the lower leg centrelines and then place them as far forward as possible with the heels
resting on the floor pan.
188.8.131.52.3. Rear Passenger's Position
Position each test dummy as specified in Paragraph 184.108.40.206.2. of this Annex, except that
feet of the test dummy are placed flat on the floorpan and beneath the front seat as far
forward as possible without front seat interference. If necessary, the distance between the
knees can be changed in order to place the feet beneath the seat.
3.1.8. All tests specified by this Standard are conducted at an ambient temperature of 18 to 28°C.
3.1.9. All tests are performed with the ignition "on."
3.2. Setup of Seat and Dummy on the Sled (BioRID II).
3.2.1. An acceleration sled with the dummy seated facing the direction of motion shall be used.
Sled accelerations shall be measured by an appropriate accelerometer attached to the sled
The temperature in the test laboratory shall be 22.5° ± 3°C with a relative humidity of
between 10% and 70%. The test dummy and seat being tested shall be soaked at this
temperature for at least 3h prior to the test.
All tests shall be performed with the active elements of the system designed to operate
during rear impact set to their operation condition (e.g. Active head restraint, Seat belt
pre-tensioner). The time to fire (TTF) required for a specific element of the active head
restraint shall be specified by the vehicle manufacturer.
3.2.2. Acceleration Sled
220.127.116.11. The parts of the vehicle structure considered essential for the replication of the vehicle
rigidity regarding the seat, its anchorages, the safety-belt anchorages and the head
restraints shall be secured to the sled.
It shall be so constructed that no permanent deformation appears after the test. Where the
upper anchorage has an adjustable height position, it shall be set nearest to the mid-range
position permitted by the design
18.104.22.168. The sled shall be capable of accommodating, in an appropriate manner, such equipment as
may be specified by the manufacturer as necessary for the correct functioning of advanced
head restraint systems (active head restraints).
22.214.171.124. A toe board comprising a horizontal section and a forward facing section oriented at 45°
from the horizontal shall be provided.
126.96.36.199. Some sled motion is allowed at the initiation of the test (T=0) however, the dummy's head,
T1 vertebra, and the sled should have the same velocity ± 0.1m/s at T=0. The back of the
dummy's head and T1 vertebra should be in the same position (±5mm) relative to the head
restraint at T=0 as the initial test set-up.
Where the adjustment of the head restraint is not automatic, it shalll be set in accordance
with the manufacturer's specification.
If a locking position midway between the lowest and the highest position does
head restraint to the position determined by the paragraphss below.
If a locking position exists within 10mm vertically upwards from the geometric mid-position,
this shalll be the test position. If no locking position exists within 10mm vertically
from the geometric mid-positionn then the next locking position down shall be the test
position. This shall be
determinedd from the top
of the headd restraint.
Head Restraint in lowermost position.
Head Restraint in uppermost position.
Horizontal mid position between lowermost and uppermost position of f the Head Restraint.
head restraint has a locking fore-aft adjustment, it shall be in the midpoint. If a
locking position exists within 10mm horizontally forwardd from the geometric mid-position,
this shall be the test position. If no locking position exists within 10mmm horizontally forwards
from the geometric mid-position
then the next locking position rearwards shall be the test
position, as shown in Figure 8-1.
If no fore-aft locking
positions are available
for the head restraint
it shall be tilted fully
188.8.131.52. Back of Head Adjustment.
184.108.40.206.1. The back of head (the most rearward position of the head when the head is horizontally
level ±1°) of the BioRID shall be positioned at the reference position described in
Paragraph 220.127.116.11. of this Annex with a tolerance of ±5mm.
18.104.22.168.2. If the test dummy back of head position is found to be different by more than ±5mm from
that of the BioRID reference back of head, obtained by the procedure specified in
Paragraph 22.214.171.124. of this Annex, then Paragraphs 126.96.36.199.2.1. and 188.8.131.52.2.2. below shall
184.108.40.206.2.1. Tip the head fore/aft no more than +3.5/-0.5° from level in order to meet the backset
220.127.116.11.2.2. After carrying out the adjustments specified in Paragraph 18.104.22.168.2.1. above and if it is still
not possible to set the test dummy backset measurement to within 15 ± 2mm of the Back of
the Head reference position specified in Paragraph 22.214.171.124. above then the dummy's pelvis
angle and the H-point position shall be adjusted within their respective tolerance bands
while prioritising the adjustment of the pelvis angle tolerance to achieve correct backset. It is
not permitted to achieve the required position by pushing the dummy rearward.
4.1.3. Calculate the HIC15 from the output of instrumentation placed in the head of the test
dummy, using the equation in Paragraph 126.96.36.199. of this Regulation and conforming to the
requirements for a 1,000Hz channel class as specified in SAE Recommended Practice
J211/1 (revision March 1995). No data generated after 200ms from the beginning of the
forward acceleration are used in determining HIC.
Sled Pulse Corridor Reference Point Locations
Reference Point Time (ms) Acceleration (m/s )
A 0 10
B 28 94
C 60 94
D 92 0
E 4 0
F 38.5 80
G 49.5 80
H 84 0
Acceleration Versus Time Curve Tolerances
Sled Pulse Corridor Reference Point Locations in Figure 8-3
Slope-Upper (m/s )
Slope-Lower (m/s )
4.2.1. Data processing and definitions
188.8.131.52. Filter with CFC 60
To ensure that low level noise does not influence the results, the acceleration signal shall be
filtered with a CFC 60 filter. The CFC 60 filter shall be used according to SAE J211, for sled
184.108.40.206. T Definition
The T (T ) shall be defined as the time 5.8ms before the CFC 60 filtered sled acceleration
reaches a 1.0g level.
220.127.116.11. T- definition
The time when the CFC 60 filtered sled acceleration for the first time is < 0g shall be called
18.104.22.168. Time Span Definition
The time span for sled pulse corridor shall be defined as dT = T- - T .
22.214.171.124. Head and Head Restraint Contact Time (T-HRCstart, T-HRCend)
Head restraint contact time start, T-HRCstart, is defined as the time (calculated from T=0) of
first contact between the back of the dummy's head and the head restraint, where the
subsequent continuous contact duration exceeds 40ms. T-HRCstart shall be expressed in
ms and rounded to one decimal place. Two decimal places of contact time (up to 1ms) are
permissible] if it can be proven that these are due to poor electrical contacts; however, these
must be investigated with reference to the film to ascertain whether the breaks in contact
are not due to biomechanical phenomena such as dummy ramping, head restraint or
seatback collapse, or "bounce" of the head during non-structural contact with the head
restraint. For the subsequent criteria, the end of head restraint contact, i.e. T-HRCend, must
also be found. This is defined as the time at which the head first loses contact with the head
restraint, where the subsequent continuous loss of contact duration exceeds 40ms.
4.3. Measurements to be Recorded
The electrical measurement data for the following parameters from the accelerometers and
load cells mounted on the corresponding parts of the dummy and on the test sled shall be
recorded from 20ms before impact to 300ms after impact or longer.
Longitudinal acceleration at the dummy's head;
Longitudinal force at the dummy's upper neck;
Vertical force at the dummy's upper neck;
Lateral axial rotation moment at the dummy's upper neck;
Longitudinal force at the dummy's lower neck;
Vertical force at the dummy's lower neck;
The NIC channel is then t calculated as a combination of relative acceleration multiplied by
0.2, and added to the
square of the relative velocity. The calculation is performed
The maximum overall NIC value (NIC ) shall be determined, considering only the t portion
of data from T=0 (start of test) until T-HRC( end) (end of contact between head and head
restraint) , as follows:
Upper Neck Shear Force (Upper Neck Fx) and Lower Neck Shear Force (Lower Neck Fx)
These are shear forces measured by the dummy's upper neck and
before the moment of rebound.
lower neck load cells
If the instrumentationn is configured in accordance with SAE J211 relative movement of the
head rearward is considered positive and relative movement of the head forward f is
Data shall be filtered at CFC 1000, and the maximum absolute valuee of the force shall be
determined, considering the portion of data from T=0 until T-HRC as follows:
Upper Neck Lateral Axial Rotationn Moment (Upper Neck My) M
This is the lateral axial rotation moment measured by the dummy'ss upper neck
before the moment of rebound.
If the instrumentation is configured in accordance withh SAE J211, positive lateral axial
rotation moment shall indicate flexion of the
neck (head rotating forwards) and
lateral axial rotation moment shall indicate extension (head rotating rearwards). Data shall
be filtered at CFC 600. Due to the construction of the dummy, d a correction shall then be
made to convert the actual moment measured by the upper neck load cell into the moment
occipital condyle (OC), as shown below:
The maximum absolute value of the moment about the OCC shall be determined, considering
the portion of data from T=0 until T-HRC(end) ).
NON-USE POSITION TEST PROCEDURE
Procedures for folding or retracting head restraints in all designated seating positions
equipped with head restraints, except the driver's designated seating position.
2. PROCEDURES TO TEST AUTOMATIC RETURN HEAD RESTRAINTS
Demonstrate compliance with Paragraph 126.96.36.199, with the ignition "on", and using a
5th percentile female Hybrid III test dummy in accordance with Paragraph 2.1. of this
Annex, or a human surrogate in accordance with Paragraph 2.2. of this Annex. Compliance is
determined at a temperature of 18 to 28°C.
2.1. 5th Percentile Hybrid III Dummy
2.1.1. Position the test dummy in the seat such that the dummy's midsagittal plane is aligned within
15mm of the seating position centreline and is parallel to a vertical plane parallel to the
vehicle vertical longitudinal zero plane.
2.1.2. Hold the dummy's thighs down and push rearward on the upper torso to maximize the
dummy's pelvic angle.
2.1.3. Place the legs as close as possible to 90° to the thighs. Push rearward on the dummy's knees
to force the pelvis into the seat so there is no gap between the pelvis and the seat back or
until contact occurs between the back of the dummy's calves and the front of the seat cushion
such that the angle between the dummy's thighs and legs begins to change.
2.1.4. Note the position of the head restraint. Remove the dummy from the seat. If the head restraint
returns to a retracted position upon removal of the dummy, manually place it in the noted
position. Determine compliance with the height requirements of Paragraph 5.1.1. by using the
test procedures of Annex 1.
2.2. Human Surrogate
A human being who weighs between 47 and 51kg, and who is between 140 and 150cm tall
may be used. The human surrogate is dressed in a cotton T-shirt, full length cotton trousers,
and sports shoes. Specified weights and heights include clothing.
2.2.1. Position the human in the centre of the seat with the pelvis touching the seat back and the
back against the seat back.
2.2.2. Verify the human's midsagittal plane is vertical and within ±15mm of the seating position
4. DISCOMFORT METRIC
Procedures for the rear and front centre designated seating positions to demonstrate
compliance with Paragraph 188.8.131.52. of this Regulation.
4.1. The H and S dimensions are defined in Figure 9-1. Figure 9-1 is a vertical fore-aft plane
passing through the R-Point (i.e. at the mid-point of the designated seating position)
intersecting the seat cushion, seat back and the head restraint.
4.2. Adjust the head restraint to the non-use position.
4.2.1. H is the distance from the R-Point to the lower edge of the head restraint measured along
the torso line.
4.2.2. S is the maximum thickness of the head restraint (as determined within 25mm of the head
restraint lower edge) measured perpendicular to the torso line between T and T from
4.2.3. P is a line parallel to the torso line which intersects the head restraint at T
4.2.4. T is the line perpendicular to the torso line and tangent to the lower edge of the head
4.2.5. T is the line parallel to and 25mm from T .
THREE-DIMENSIONAL REFERENCE SYSTEM
1. The three dimensional reference system is defined by three orthogonal planes established by the
vehicle manufacturer (see Figure 10-1)
2. The vehicle measuring attitude is established by positioning the vehicle on the supporting
surface such that the co-ordinates of the fiducial marks correspond to the values indicated by the
3. The coordinates of the "R" Point and the "H" Point are established in relation to the fiducial
marks defined by the vehicle manufacturer.
Three-dimensional Reference System
3.4. The area of the seating position contacted by the 3-D H machine is covered by a muslin
cotton, of sufficient size and appropriate texture, described as a plain cotton fabric having
18.9 threads per cm and weighing 0.228kg/m or knitted or non-woven fabric having
If the test is run on a seat outside the vehicle, the floor on which the seat is placed shall have
the same essential characteristics (tilt angle, height difference with a seat mounting, surface
texture, etc.) as the floor of the vehicle in which the seat is intended to be used.
3.5. Place the seat and back assembly of the 3-D H machine so that the centre plane of the
occupant (C/LO) coincides with the centre plane of the 3-D H machine. At the manufacturer's
request, the 3-D H machine may be moved inboard with respect to the C/LO if the
3-D H machine is located so far outboard that the seat edge will not permit levelling of the
3-D H machine.
3.6. Attach the foot and lower leg assemblies to the seat pan assembly, either individually or by
using the T bar and lower leg assembly. A line through the "H" Point sight buttons is parallel
to the ground and perpendicular to the longitudinal centre plane of the seat.
3.7. Adjust the feet and leg positions of the 3-D H machine as follows:
3.7.1. In the case of front outboard seats:
184.108.40.206. Both feet and leg assemblies are moved forward in such a way that the feet take up natural
positions on the floor, between the operating pedals if necessary. Where possible the left foot
is located approximately the same distance to the left of the centre plane of the
3-D H machine as the right foot is to the right. The spirit level verifying the transverse
orientation of the 3-D H machine is brought to the horizontal by readjustment of the seat pan if
necessary, or by adjusting the leg and foot assemblies towards the rear. The line passing
through the H-Point sight buttons is maintained perpendicular to the longitudinal centre plane
of the seat.
220.127.116.11. If the left leg cannot be kept parallel to the right leg and the left foot cannot be supported by
the structure, move the left foot until it is supported. The alignment of the sight buttons is
3.7.2. In the case of rear outboard seats:
For rear seats or auxiliary seats, the legs are located as specified by the manufacturer. If the
feet then rest on parts of the floor which are at different levels, the foot which first comes into
contact with the front seat shall serve as a reference and the other foot is so arranged that the
spirit level giving the transverse orientation of the seat of the device indicates the horizontal.
3.7.3. In the case of other seats:
The general procedure indicated in Paragraph 3.7.1. of this Annex is followed except that the
feet are placed as specified by the vehicle manufacturer.
3.8. Apply lower leg and thigh weights and level the 3-D H machine.
3.13. Holding the T bar to prevent the 3-D H machine from sliding forward on the seat cushion,
proceed as follows:
3.13.1. Return the back pan to the seat back;
3.13.2. Alternately apply and release a horizontal rearward load, not to exceed 25N, to the back
angle bar at a height approximately at the centre of the torso weights until the hip angle
quadrant indicates that a stable position has been reached after load release. Care is
exercised to ensure that no exterior downward or lateral loads are applied to the
3-D H machine. If another level adjustment of the 3-D H machine is necessary, rotate the
back pan forward, re-level, and repeat the procedure from Paragraph 3.12. of this Annex.
3.14. Take all measurements:
3.14.1. The coordinates of the "H" Point are measured with respect to the three dimensional
3.14.2. The actual torso angle is read at the back angle quadrant of the 3-D H machine with the
probe in its fully rearward position.
3.15. If a rerun of the installation of the 3-D H machine is desired, the seat assembly should remain
unloaded for a minimum period of 30min prior to the rerun. The 3-D H machine should not be
left loaded on the seat assembly longer than the time required to perform the test.
3.16. If the seats in the same row can be regarded as similar (bench seat, identical seats, etc.) only
one "H" Point and one "actual torso angle" is determined for each row of seats, the
3-D H machine described in Annex 12 being seated in a place regarded as representative for
the row. This place is:
3.16.1. In the case of the front row, the driver's seat;
3.16.2. In the case of the rear row or rows, an outer seat.
3-D H Machine Elements Designation