[Federal Register Volume 87, Number 125 (Thursday, June 30, 2022)]
[Rules and Regulations]
[Pages 39234-39317]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-13658]
[[Page 39233]]
Vol. 87
Thursday,
No. 125
June 30, 2022
Part III
Department of Homeland Security
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49 Part 571
Federal Motor Vehicle Safety Standards; Child Restraint Systems, Child
Restraint Systems--Side Impact Protection, Incorporation by Reference;
Final Rule
Federal Register / Vol. 87 , No. 125 / Thursday, June 30, 2022 /
Rules and Regulations
[[Page 39234]]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
[Docket No. NHTSA-2022-0051]
RIN 2127-AK95
Federal Motor Vehicle Safety Standards; Child Restraint Systems,
Child Restraint Systems--Side Impact Protection, Incorporation by
Reference
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation (DOT).
ACTION: Final rule.
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SUMMARY: This final rule amends Federal Motor Vehicle Safety Standard
(FMVSS) (Standard) No. 213, ``Child restraint systems,'' and adds FMVSS
No. 213a, which is referenced by Standard No. 213. This final rule
fulfills a statutory mandate set forth in the ``Moving Ahead for
Progress in the 21st Century Act'' (MAP-21) that directed the Secretary
of Transportation (NHTSA by delegation) to issue a final rule to
improve the protection of children seated in child restraint systems
during side impacts.
DATES:
Effective date: August 1, 2022. The incorporation by reference of
the publications listed in the rule is approved by the Director of the
Federal Register as of August 1, 2022.
Compliance date: June 30, 2025. Optional early compliance is
permitted.
Petitions for reconsideration: Petitions for reconsideration of
this final rule must be received no later than August 15, 2022.
ADDRESSES: Petitions for reconsideration of this final rule must refer
to the docket and notice number set forth above and be submitted to the
Administrator, National Highway Traffic Safety Administration, 1200 New
Jersey Avenue SE, Washington, DC 20590. Note that all petitions
received will be posted without change to http://www.regulations.gov,
including any personal information provided. To facilitate social
distancing due to COVID-19, please email a copy of the petition to
[email protected].
Privacy Act. The petition will be placed in the docket. Anyone is
able to search the electronic form of all documents received into any
of our dockets by the name of the individual submitting the comment (or
signing the comment, if submitted on behalf of an association,
business, labor union, etc.). You may review DOT's complete Privacy Act
Statement in the Federal Register published on April 11, 2000 (Volume
65, Number 70; Pages 19477-78) or you may visit https://www.transportation.gov/individuals/privacy/privacy-act-system-records-notices.
FOR FURTHER INFORMATION CONTACT: For technical issues, you may call
Cristina Echemendia, Office of Crashworthiness Standards, telephone
202-366-6345, email [email protected]. For legal issues,
Deirdre Fujita or Hannah Fish, Office of the Chief Counsel, telephone
202-366-2992, email [email protected] or [email protected]. The
mailing address of these officials is the National Highway Traffic
Safety Administration, U.S. Department of Transportation, 1200 New
Jersey Avenue SE, West Building, Washington, DC 20590.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Executive Summary
II. Safety Need
III. Statutory Mandate
IV. Guiding Principles
V. Overview of the NPRM and Comments Received
a. Overview of the NPRM
b. Summary of the Comments
VI. Response to the Comments (Wide-Reaching Issues)
a. Are efforts better spent elsewhere on child restraint
systems?
b. Will child restraints become excessively large and heavy?
c. More Bulk Is Not Necessarily Advantageous; the 2017 Test
Program
d. The 40-lb Limit for Coverage of the Standard
e. Improving Side Impact Protection for Children Older Than 3-
Years-Old
f. Weight as a Limiting Factor
g. Labeling CRSs for Children Weighing Over 18.1 kg (40 lb)
1. Label as ``Not Tested in Side Impacts''
2. Head Under Window Sill
VII. Aspects of the FMVSS 213a Test Procedure
a. Overview
b. Side Impact Seat Assembly Characteristics
1. Seat Characteristics
i. Rear Seat Cushion Stiffness
ii. Lower Anchorages and Top Tether Anchorages of the CRAS
2. Door Characteristics
i Beltline Height
ii. Door and Armrest Thickness and Stiffness
3. Honeycomb
4. SISA Technical Drawings
5. Other Testing Issues
i. Right-Side Impacts
ii. Sliding Seat Bearings
iii. Seat Belt Interference
c. Sled Kinematic Parameters
1. General
2. Specific Issues
i. Sliding Seat Acceleration Profile
ii. Tuning the Test To Account for Lighter Dummies
iii. Acceleration Corridor
3. Door Parameters
4. Relative Door Velocity Profile
5. Relative Velocity at Impact Time (T0)--Tolerance
6. Longitudinal Crash Component
d. Test Set Up and Procedure
1. CRS Attachment
i. Lower Anchor and/or Seat Belt CRS Installation
ii. Tethered vs. Non-Tethered CRS Installation
iii. Distance Between Edge of Armrest and Edge of Seat
e. Dummy Positioning
f. Dummy Selection
g. Miscellaneous Comments on the Test Procedure, Including Test
Setup, Sled Instrumentation, and Data Processing
h. Additional Changes
VIII. Performance Requirements
a. Q3s
1. Q3s Sourcing
2. Biofidelity Issues
3. Aspects of Testing With the Q3s
i. Reversibility
ii. HIII 3-Year-Old Child Test Dummy as an Alternative
4. Q3s Performance Measures
i. Head Injury Criterion (HIC)
ii. Head Contact (Not Assessed)
iii. Chest Deflection
b. CRABI 12-Month-Old
1. Alternative ATDs
2. Durability
3. Head-to-Door Contact
4. Component Test
5. CRS System Integrity and Energy Distribution
IX. Repeatability and Reproducibility
X. Lead Time and Effective Date
XI. Regulatory Notices and Analyses
This final rule amends FMVSS No. 213, ``Child restraint systems,''
to establish side impact performance requirements for child restraint
systems (CRS) designed to seat children weighing up to 18.1 kilograms
(kg) (40 pounds (lb)), or for children in a height range that includes
heights up to 1100 millimeters (43.3 inches.) The side impact
performance requirements are established in a new FMVSS No. 213a, which
is referenced by Standard No. 213. This final rule fulfills a statutory
mandate set forth in MAP-21 that directed the Secretary of
Transportation (NHTSA by delegation) to issue a final rule to improve
the protection of children seated in child restraint systems during
side impacts.
Standard No. 213a requires child restraints designed to seat
children weighing up to 18.1 kg (40 lb), or for children in a height
range that includes heights up to 1100 millimeters (43.3 inches) to
meet performance criteria when tested in a dynamic test replicating a
vehicle-to-vehicle side impact. The child restraints must provide
proper restraint, manage side
[[Page 39235]]
crash forces, and protect against harmful head and chest contact with
intruding structures. In addition, child restraints will be required to
meet other performance requirements in the sled test to ensure, among
other things, the restraint can withstand crash forces from a side
impact without collapsing or fragmenting in a manner that could harm
the child. This new standard will reduce the number of children killed
or injured in side crashes.
I. Executive Summary
Front and side crashes account for most child occupant fatalities.
FMVSS No. 213 currently specifies performance requirements that child
restraint systems (CRSs) must meet in a sled test simulating a frontal
impact. This final rule expands the standard to adopt a side impact
test. Child restraints subject to this final rule must pass the new
side impact test in addition to the frontal impact test.
Impacts to the side of a vehicle rank almost equal to frontal
crashes as a source of occupant fatalities and serious injuries to
children ages 0 to 12 years. Side impacts are especially dangerous when
the impact is on the passenger compartment because, unlike a frontal or
rear-end crash, there are no substantial, energy absorbing structures
between the occupant and the impacting vehicle or object. The door
collapses into the passenger compartment and the occupants contact the
door relatively quickly after the crash at a high relative velocity.\1\
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\1\ Kahane, November 1982, NHTSA Report No. DOT HS 806 314.
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In a typical vehicle-to-vehicle side impact similar to the one
represented in Standard No. 214, ``Side impact protection'' (49 CFR
571.214), the striking vehicle first interacts with the door structure
of the struck vehicle and commences to crush the door, causing it to
intrude laterally into the vehicle compartment. The striking vehicle
then engages the sill of the struck vehicle and begins to push the
struck vehicle away. At this point, the occupant sitting on the struck
side of the vehicle experiences the struck vehicle seat moving away
from the impacting vehicle while the door intrudes towards him or her.
The intruding door impacts the occupant and the occupant is accelerated
with the door along the impact direction until the occupant reaches the
velocity of the struck and striking vehicle.
Standard No. 214, protects against unreasonable risk of injury or
death to occupants in vehicle-to-vehicle crashes and other side
crashes. The standard has benefited all occupants,\2\ but due to their
size and fragility, infants and young children are dependent on child
restraint systems to supplement those protections. Child restraints
with internal harnesses (commonly called ``car seats,'' ``child seats''
or ``safety seats'') are highly effective safety devices. Although
child seats are not currently subject to side impact testing, NHTSA
estimates that these types of child restraints are already 42 percent
effective in preventing death in side crashes of children 0- to 3-
years-old.\3\ This estimated degree of effectiveness is high, and is
only 11 percentage points lower than Child Restraint System (CRS)
effectiveness in frontal crashes (53 percent). Child safety seats are
effective because they restrain the child within the child seat and
prevent harmful contact with interior vehicle components, and have
padding and an outer shell structure that shields the child and absorbs
some of the crash forces.
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\2\ Kahane, C.J. (2015, January). Lives saved by vehicle safety
technologies and associated Federal Motor Vehicle Safety Standards,
1960 to 2012--Passenger cars and LTVs--With reviews of 26 FMVSS and
the effectiveness of their associated safety technologies in
reducing fatalities, injuries, and crashes. (Report No. DOT HS 812
069). Washington, DC: National Highway Traffic Safety
Administration. Link: https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/812069.
\3\ NHTSA conducted an analysis of the Fatality Analysis
Reporting System (FARS) data files of real world fatal non-rollover
frontal and side crashes of passenger cars and light trucks and vans
involving children for the years 1995 to 2009. From this analysis,
the agency estimated the effectiveness of CRSs in preventing
fatalities among 0- to 3-year-old children to be 42 percent in side
crashes and 53 percent in frontal crashes. The analysis method is
similar to that reported in the NCSA Research Note, ``Revised
Estimates of Child Restraint Effectiveness,'' DOT HS 96855 and is
also detailed in the technical report in the NPRM docket (https://www.regulations.gov/document/NHTSA-2014-0012-0002).
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Because MAP-21 directed NHTSA to amend FMVSS No. 213 to improve
side impact protection, NHTSA designed this final rule to work within
the framework of the existing frontal standard. Child restraint systems
are tested in FMVSS No. 213 when attached to a standardized seat
assembly representative of a passenger vehicle seat. Child restraints
are tested with anthropomorphic test devices (ATDs) (test dummies)
representative of the children for whom the CRS is recommended.\4\
FMVSS No. 213 requires child restraints to limit the amount of inertial
load that can be exerted on the head and chest of the dummy during the
dynamic test. The standard requires child restraints to meet head
excursion \5\ limits to reduce the possibility of head injury from
contact with vehicle interior surfaces and ejection. Child restraints
must also maintain system integrity (i.e., not fracture or separate in
such a way as to harm a child), and have no contactable surface that
can harm a child in a crash. There are requirements to ensure belt
webbing can safely restrain the child, and that buckles can be swiftly
unlatched after a crash by an adult but cannot be easily unbuckled by
an unsupervised child. Child restraints other than booster seats and
harnesses \6\ must pass performance requirements when attached to the
standard seat assembly with only a lap belt,\7\ and, in a separate
assessment, with only the lower anchorages of a child restraint
anchorage system (CRAS).\8\ The CRSs must meet more stringent head
excursion requirements in another test where a top tether, if provided,
may be attached. Belt-positioning (booster) seats are tested on the
standard seat assembly using a Type 2 (lap and shoulder) belt.
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\4\ Standard No. 213 specifies the use of test dummies
representing a newborn, a 12-month-old, 3- and 6-year-old, weighted
6-year-old, and 10-year-old child. The ATDs other than the newborn
are equipped with instrumentation measuring crash forces, but NHTSA
restricts some measurements from the weighted 6-year-old and 10-
year-old dummies due to technical limits of the dummies.
\5\ Head excursion refers to the distance the dummy's head
translates forward in FMVSS No. 213's simulated frontal crash test.
\6\ These types of child restraint systems are defined in FMVSS
No. 213.
\7\ As explained in more detail below, NHTSA published an NPRM
on November 2, 2020 (85 FR 69388) to amend the standard seat
assembly in FMVSS No. 213 ``to better simulate a single
representative motor vehicle rear seat.'' Among other matters, the
NPRM proposes replacing the lap belt test with a lap and shoulder
belt (Type 2 belt) test.
\8\ Commonly called ``LATCH,'' which refers to Lower Anchors and
Tethers for Children, an acronym developed to refer to the child
restraint anchorage system required by FMVSS No. 225 for
installation in motor vehicles (49 CFR 571.225, ``Child restraint
anchorage systems''). A child restraint anchorage system consists of
two lower anchorages, and one upper tether anchorage. Each lower
anchorage includes a rigid round rod, or ``bar,'' onto which a hook,
a jaw-like buckle or other connector can be snapped. The bars are
located at the intersection of the vehicle seat cushion and seat
back. The upper tether anchorage is a ring-like object to which the
upper tether of a child restraint system can be attached. FMVSS No.
213 requires CRSs to be equipped with attachments that enable the
CRS to attach to the vehicle's child restraint anchorage system.
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This final rule establishes requirements for a side impact test
that are equivalent to those described above, and makes child restraint
systems even more protective of child occupants than they are now. It
adopts performance thresholds that ensure child restraints protect
against unreasonable risk of head and chest injury in side crashes, and
a performance test that objectively assesses and assures achievement of
such performance.
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The standard adopted by this final rule applies to child restraints
for children weighing up to 18.1 kg (40 lb) or for children up to 1100
millimeters (mm) (43.3 inches, or 3 feet, 7 inches) in standing
height.\9\ These children would be virtually all 3-year-olds and almost
all 4-year-olds. The 18.1 kg (40 lb) threshold is greater than the
weight of a 97th percentile 3-year-old (17.7 kg (39.3 lb)) and is
approximately the weight of an 85th percentile 4-year-old. The 1100 mm
(43.3 inches) height threshold is more than the height of a 97th
percentile 3-year-old (1024 mm (40.3 inches)) and corresponds to the
height of a 97th percentile 4-year-old. While the standard would apply
to child restraints that are recommended for use by children weighing
less than 18.1 kg (40 lb) or with heights under 1100 mm (43.3 inches),
as explained in a later section, the countermeasures (padding and side
structure) designed into a safety seat to meet the standard may also
provide side impact protection even as the child surpasses the 18.1 kg
(40 lb) or 1100 mm (43.3 inches) mark. Many child safety seats are
recommended for children much heavier than 18.1 kg (40 lb) or taller
than 1100 mm (43.3 inches). Children kept in such seats will benefit
from the countermeasures as they grow heavier than 18.1 kg (40 lb) or
taller than 1100 mm (43.3 inches). NHTSA quantified the benefits of
this rule for children up to age 4 but believes that children older
than age 4 would benefit from this final rule as well.
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\9\ The agency added a height provision to make the new
standard's applicability clear to booster seat manufacturers who
choose not to label their restraints with a weight recommendation.
Although all current belt-positioning boosters are labeled with both
height and weight recommendations, FMVSS No. 213 permits
manufacturers of belt-positioning booster seats to delete the
reference to maximum weight (see FMVSS No. 213, S5.5.2(f)). In view
of that provision, for manufacturers that only provide a height
limit, the application section of FMVSS No. 213a will be clear as to
the applicability of the standard to their restraints. When this
final rule preamble refers to a ``40 lb weight limit'' we mean the
term to be synonymous with a height limit of 1100 mm for belt-
positioning boosters that only provide a height limit.
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This final rule adopts a dynamic sled test simulating a full-scale
vehicle-to-vehicle side impact, which is the first-of-its-kind
simulating both an intruding door and a longitudinal crash component.
Child restraints recommended \10\ for children weighing 13.6 to 18.1 kg
(30 to 40 lb) are tested with an instrumented side impact test dummy
representing a 3-year-old child, called the Q3s dummy.\11\ Child
restraints designed for children weighing up to 13.6 kg (30 lb) are
tested with an established 12-month-old child test dummy (the 12-month-
old Child Restraint Air Bag Interaction (CRABI) dummy).\12\ The new
standard requires CRSs to restrain the dummy in the side test, manage
side crash forces and prevent harmful head contact with side
structures. Child restraints tested with the Q3s must also limit crash
forces to the dummy's chest. Following the dynamic side impact test,
child restraints will be assessed for their compliance with
requirements for system integrity, contactable surfaces, and buckle
release, just like they are following Standard No. 213's frontal impact
test.
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\10\ When we describe a child restraint as ``recommended for''
children of a certain height or weight range, we mean the child
restraint manufacturer is manufacturing for sale, selling or
offering the CRS for sale as suitable for children in that height or
weight range.
\11\ The Q3s is NHTSA's first child test dummy designed for side
impacts. NHTSA published a final rule on November 3, 2020 that
adopted the Q3s into NHTSA's regulation for anthropomorphic test
devices. 85 FR 69898.
\12\ 49 CFR part 572, subpart R.
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Work Preceding This Final Rule
NHTSA published the notice of proposed rulemaking (NPRM) preceding
this final rule on January 28, 2014 (79 FR 4570).\13\ Enhanced side
impact protection for children has long been a priority for NHTSA.
NHTSA laid the necessary groundwork for this final rule over the years
preceding and since the NPRM.\14\
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\13\ Docket No. NHTSA 2014-0012.
\14\ An overview of NHTSA's work developing FMVSS No. 213a can
be found in section IX of the January 28, 2014 NPRM, 79 FR at 4579-
4590.
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To develop the NPRM, NHTSA examined data on the fatalities of young
children to see how children are killed and injured in side crashes,
the characteristics of the crashes that are injuring them, and the
types of injuries they suffer. Among CRS-restrained children killed in
side crashes, about 60 percent were in near-side impacts,\15\ leading
NHTSA to focus development on a near-side sled test. Intrusion was
found to be an important causative factor for moderate to serious
injury, which led NHTSA to concentrate on developing a side impact test
procedure that included intrusion into the occupant space.\16\ Data
indicated that children restrained in child restraints exhibited more
head injuries (59 percent) compared to torso injuries (22 percent) and
injuries to extremities (14 percent). NHTSA used these and other data
to develop the first-of-its-kind safety standard on child side impact
protection involving a near-side impact with a longitudinal crash
component and an intruding vehicle door.
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\15\ See NPRM for this final rule, 79 FR 4570, Table 6. The NPRM
also noted that among CRS-restrained children with moderate to
higher severity injuries in side crashes, over 60 percent were in
near-side impacts (Table 8).
\16\ Sherwood, see footnotes 40, 43 and 44 of the NPRM.
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Following publication of the NPRM, NHTSA conducted a multi-year
research program from 2014 to 2016 to broaden the assessment of the Q3s
in providing repeatable and reproducible test results in side impact
testing. NHTSA designed a test program involving Humanetics Innovative
Solutions, Inc. (a dummy manufacturer), several private dummy owners
(CRS manufacturers), two independent testing labs, and NHTSA's Vehicle
Research and Test Center (VRTC). This work validated the performance
specifications of the NPRM, thus better ensuring that all future Q3s
dummies will be uniform, and provided information for NHTSA to use in
prescribing specifications for the Q3s. Information from that program
refined the set of engineering drawings and the series of dummy-only
impact tests used for production and qualification of the Q3s.\17\ The
test program enabled NHTSA to produce a set of fully-vetted engineering
specifications and an objective set of qualification standards. These
materials guarantee a high level of uniformity in any conforming Q3s
unit used to assess CRS performance in a side impact test.
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\17\ The drawings describe every part on the dummy and may be
used to inspect dummies purchased from a dummy manufacturer. The
impact tests used by CRS manufacturers and other end-users serve as
a final check to ensure that the assembled dummy will perform as
prescribed by NHTSA in 49 CFR part 572.
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Through research from 2015 to 2017, NHTSA adjusted the side impact
sled test assembly to reduce variability in results and more closely
align the assembly with current vehicle seats. In 2017, NHTSA undertook
fleet testing to obtain current data of CRS performance in side impacts
using the refined side impact seat assembly. These research projects
are discussed in detail in sections below in this preamble.
FMVSS No. 214 and No. 226
FMVSS No. 214 played a critical role in developing this final rule.
NHTSA designed the side impact test to replicate the FMVSS No. 214
moving deformable barrier (MDB) test, as the MDB test simulates a full-
scale severe intersection collision of an impacting vehicle
(represented by a 1,360 kg (3,000 lb) MDB) traveling at 48.3 km/h (30
mph) striking the side of a test vehicle traveling at 24 km/h (15
mph).\18\ The MDB test replicated in this final rule involves a change
of velocity of
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approximately 30.5 km/h (19 mph). NHTSA's analysis of field data (NASS-
CDS 1995-2009) found that 92 percent of near-side crashes for
restrained children (0 to 12 years-old) involved a change in velocity
of 30.5 km/h (19 mph) or lower.
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\18\ FMVSS No. 214 MDB test (49 CFR 571.214, S7).
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NHTSA designed this rule to account for the safety countermeasures
installed in vehicles to meet FMVSS No. 214 as practicably possible, to
make a realistic assessment of how a CRS will perform when subjected to
a side crash in the real world. To achieve this, NHTSA used compliance
test data from MDB tests where the vehicle passed the FMVSS No. 214
test, to replicate the characteristics of passenger-carrying vehicles
on the road. Furthermore, NHTSA designed FMVSS No. 213a to replicate a
collision of the striking MDB with a small vehicle rather than a larger
vehicle. NHTSA sought to replicate the characteristics of a small
passenger car, as opposed to a larger vehicle, because smaller cars
generally present a more demanding side impact test condition than
larger vehicles, since smaller cars generally have a higher change in
velocity than larger ones when impacted by the same MDB. Testing child
restraints under the more severe condition better ensures they will
provide the threshold level of protection required by the standard in
both small cars and large cars than if they were assessed under
conditions replicating large cars alone.
Standard No. 214's pole test and FMVSS No. 226, Ejection
mitigation,\19\ were also integral to development of this final rule.
To meet the pole test, manufacturers equip passenger vehicles with side
air bags in front seating positions to protect against unreasonable
risk of head and chest injuries. To meet the pole test and FMVSS No.
226 requirements, manufacturers install side curtain air bags \20\ to
deploy in both side impacts and in rollovers, and design them to cover
all side windows at the vehicle's front, second and third rows, from
the roof line to the window sill. Consequently, vehicles are currently
produced with side curtain air bags that cover the entire side window
for front and rear row seats in both side impacts and rollovers. NHTSA
developed FMVSS No. 213a recognizing that these side curtain air bags
can protect passengers in rear seating positions against unreasonable
risk of head injury in side impact crashes, including older children in
booster seats.
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\19\ FMVSS No. 214, S9. The pole test protects against side
crashes of passenger vehicles into structures such as telephone
poles and trees. It is a near-side impact. NHTSA established FMVSS
No. 226 (49 CFR 571. 226) in 2011 (76 FR 3212). The standard was
phased in starting in 2013, with full compliance required for
vehicles manufactured on or after September 1, 2017.
\20\ In the final rule adopting the pole test into FMVSS No.
214, NHTSA anticipated that side curtain air bags installed to meet
FMVSS No. 214 would also be the countermeasure to meet the then-
pending ejection mitigation standard. NHTSA anticipated side impact
curtain air bags would extend to rear seating positions, and that
occupants in rear seating positions would benefit from the side
curtain air bags in side impacts. NHTSA stated: ``We believe that
manufacturers will install curtains in increasing numbers of
vehicles in response to this [FMVSS No. 214] final rule, the
voluntary commitment, and in anticipation of NHTSA's ejection
mitigation rulemaking. The curtains will provide head protection to
front and rear seat occupants in side impacts.'' 72 FR 51911, 51933;
Sept. 11, 2007.
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Details of This Final Rule
The side impact sled test adopted by this final rule tests child
restraints in a manner that simulates the vehicle acceleration and
intruding door in a realistic side impact.\21\ The test seat assembly
on which a CRS is tested replicates the rear seating position nearest
to the side impact (near-side impact), as data show near-side impacts
are more injurious than far-side impacts, accounting for 81 percent of
moderate-to-critical injuries to restrained 0- to 3-year-old children
involved in side crashes. Most of these moderate-to-critical injuries
in near-side impacts are due to impact with interior surfaces in the
vehicle, and in near-side impacts, the interior surface is usually the
intruding door.\22\ In far-side impacts, the impact surfaces vary
considerably depending on the crash dynamics, and therefore are
difficult to characterize. For these reasons, standards established
worldwide for side impact protection of children focus on near-side
impacts, and FMVSS No. 214's moving deformable barrier and pole tests
involve only near-side impacts.
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\21\ Data show that door intrusion is a causative factor for
moderate and serious injury to children in side impacts. Arbogast,
supra.
\22\ Arbogast, et al., ``Injury Risks for Children in Child
Restraint Systems in Side Impact Crashes'' (2004); Arbogast, et al.,
``Protection of Children Restrained in Child Safety Seats in Side
Impact Crashes'' (2010); McCray et al., ``Injuries to Children One
to Three Years Old in Side Impact Crashes'' (2007).
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This final rule applies to CRSs designed to seat children weighing
up to 18.1 kg (40 lb). NHTSA did not specify a limit above 18.1 kg (40
lb) because there is no side impact dummy representative of children
weighing more than 18.1 kg (40 lb) that is proven to provide the
reliable test measurements required of a test instrument used in the
FMVSSs.\23\ NHTSA is concerned that, without a valid test dummy, CRSs
for heavier children may ``pass'' a side impact test with a smaller
dummy but the dummy would not meaningfully assess the performance of
the CRS in protecting a larger child. Raising the limit above 18.1 kg
(40 lb) could engender a false sense of security that the CRS
adequately protects the heavier (larger) children when, in fact, the
assessment of performance was meaningless.
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\23\ As noted earlier, the final rule applies to CRSs designed
for children weighing up to 18.1 kg (40 lb) and with standing height
up to 1100 mm (43.3 inches), which covers more than 97 percent of 3-
year-old children and about 85 percent of 4-year-old children. The
Q3s child dummy has weight and height representative of an average
3-year-old child.
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NHTSA also decided to adopt a 40-lb weight limit after considering
the overall side impact protection provided by the FMVSSs and the
ongoing and potential work on child restraint safety. As explained
above, FMVSS No. 214's side impact tests were highly important to
NHTSA's design of FMVSS No. 213a and implementation of MAP-21. Children
over 40 lb would be provided side impact protection by remaining in a
CRS meeting FMVSS No. 213a for as long as the manufacturer recommends,
which typically exceeds a weight above 40 lb.\24\ When children outgrow
their safety seats, they transition to a booster seat, which on average
raises a seated child by 82 mm (3.22 inches),\25\ which would position
the child high enough to benefit from the vehicle's side curtain air
bags installed to meet Standards Nos. 214 and 226.
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\24\ Out of the 107 models of forward-facing CRSs with internal
harness (convertibles, combination and all-in-one CRSs) in the
market, 85.9% have a maximum weight recommendation of 65 pounds,
10.2% have a maximum weight recommendation of 40 pounds and only
3.7% have a 50 pound maximum weight recommendation.
\25\ The agency determined the height that a booster seat raises
a seated child (boosting height) by measuring the difference in the
H-point (marker on the hip) of the HIII-6-year-old dummy when the
dummy is seated on the side impact seat assembly specified in this
final rule (SISA) with no booster seat and when the dummy is seated
on the SISA in a booster seat. The boosting height measured for 15
booster seat models ranged from 43 mm (1.69 inches) to 104 mm (4.09
inches) with an average boosting height of 83 mm (3.26 inches). A
document with the measurements is docketed with this final rule.
---------------------------------------------------------------------------
On November 2, 2020, NHTSA proposed to update FMVSS No. 213's
frontal impact test requirements, including the seat assembly and other
changes to the standard.\26\ In that
[[Page 39238]]
NPRM, NHTSA proposed that booster seats must be labeled as suitable
only for children weighing more than 18.1 kg (40 lb).\27\ This final
rule is consistent with that proposal to ensure that children remain in
car seats providing side impact protection longer, and will transition
to booster seats only when they are large enough to take advantage of
the vehicle's side air bag countermeasures.
---------------------------------------------------------------------------
\26\ 85 FR 69388, November 2, 2020, Docket NHTSA-2020-0093.
Section 31501(b) of MAP-21 Subtitle E, directed NHTSA to undertake
rulemaking to amend the standard seat assembly in FMVSS No. 213 ``to
better simulate a single representative motor vehicle rear seat.''
Among other matters, as part of updating the standard seat assembly,
the NPRM proposed replacing the lap belt currently on the test
assembly with a lap and shoulder belt. MAP-21 requires NHTSA to
issue a final rule adopting an updated seat assembly.
\27\ 85 FR at 69427, col. 3. NHTSA currently recommends that
children riding forward-facing should be restrained in CRSs with
internal harnesses (car safety seats) as long as possible before
transitioning to a booster seat. https://www.nhtsa.gov/equipment/car-seats-and-booster-seats#age-size-rec. FMVSS No. 213 currently
permits booster seats only to be recommended for children weighing
at least 13.6 kg (30 lb) (S5.5.2(f)). Based on an analysis of field
data and other considerations, NHTSA believes the 13.6 kg (30 lb)
value should be raised. Thirty pounds corresponds to the weight of a
50th percentile 3-year-old, and to the weight of a 95th percentile
18-month-old; i.e., children too small to be safely protected in a
booster seat. In the November 2, 2020 NPRM, NHTSA proposed to amend
S5.5.2(f) to raise the 13.6 kg (30 lb) limit to 18.2 kg (40 lb),
which is greater than the weight of a 97th percentile 3-year-old
(17.7 kg (39.3 lb)) and approximately the weight of an 85th
percentile 4-year-old.
---------------------------------------------------------------------------
Estimated Benefits and Costs
NHTSA estimates that this final rule will reduce 3.7 fatalities and
41 (40.9) non-fatal injuries (MAIS \28\ 1-5) annually (see Table 1
below).\29\ The equivalent lives and the monetized benefits were
estimated in accordance with guidance issued in March 2021 by the
Office of the Secretary \30\ regarding the treatment of value of a
statistical life in regulatory analyses. This final rule is estimated
to save 15.1 equivalent lives annually. The monetized annual benefits
of this final rule at 3 and 7 percent discount rates are $169.0 million
and $152.2 million, respectively (Table 2). NHTSA estimates that the
annual cost of this final rule is approximately $7.37 million. The
countermeasures may include larger wings and padding with energy
absorption characteristics that cost, on average, approximately $0.58
per CRS designed for children in a weight range that includes weights
up to 40 lb (both forward-facing and rear-facing) (Table 3 below). The
annual net benefits are estimated to be $144.8 million (7 percent
discount rate) to $161.6 million (3 percent discount rate) as shown in
Table 4. Because this final rule is cost beneficial just by comparing
costs to monetized economic benefits, and there is a net benefit, NHTSA
has not provided a net cost per equivalent life saved as there is no
additional value provided by such an estimate.
---------------------------------------------------------------------------
\28\ MAIS (Maximum Abbreviated Injury Scale) represents the
maximum injury severity of an occupant based on the Abbreviated
Injury Scale (AIS). AIS ranks individual injuries by body region on
a scale of 1 to 6: 1 = minor, 2 = moderate, 3 = serious, 4 = severe,
5 = critical, and 6 = maximum (untreatable). MAIS 3 + injuries
represent MAIS injuries at an AIS level of 3, 4, 5, or 6.
\29\ NHTSA has developed a Final Regulatory Impact Analysis
(FRIA) that discusses issues relating to the potential costs,
benefits, and other impacts of this regulatory action. The FRIA is
available in the docket for this final rule and may be obtained by
downloading it or by contacting Docket Management at the address or
telephone number provided at the beginning of this document.
\30\ https://www.transportation.gov/office-policy/transportation-policy/revised-departmental-guidance-on-valuation-of-a-statistical-life-in-economic-analysis.
Table 1--Annual Estimated Benefits
------------------------------------------------------------------------
------------------------------------------------------------------------
Fatalities.............................................. 3.7
Non-fatal injuries (MAIS 1 to 5)........................ 41 (40.9)
------------------------------------------------------------------------
Table 2--Estimated Monetized Benefits
[In millions of 2020 dollars]
----------------------------------------------------------------------------------------------------------------
Value of
Economic statistical Total benefits
benefits life
----------------------------------------------------------------------------------------------------------------
3 Percent Discount Rate......................................... $26.24 $142.72 $168.97
7 Percent Discount Rate......................................... 23.63 128.53 152.16
----------------------------------------------------------------------------------------------------------------
Table 3--Estimated Costs
[2020 Economics]
------------------------------------------------------------------------
------------------------------------------------------------------------
Average cost per CRS designed for $0.58.
children in a weight range that includes
weights up to 40 lb.
------------------------------
Total annual cost...................... 7.37 million.
------------------------------------------------------------------------
Table 4--Annualized Costs and Benefits
[In millions of 2020 dollars]
----------------------------------------------------------------------------------------------------------------
Annualized Annualized
costs benefits Net benefits
----------------------------------------------------------------------------------------------------------------
3% Discount Rate................................................ $7.37 $168.97 $161.60
7% Discount Rate................................................ 7.37 152.16 144.79
----------------------------------------------------------------------------------------------------------------
How This Final Rule Differs From the NPRM
For the convenience of the reader, the notable changes from the
NPRM are described below. They are explained in detail in relevant
sections throughout this preamble. More minor changes (e.g.,
positioning the arm of the Q3s) are not highlighted below but are
discussed in the sections of this preamble relating to the topic.
The side impact seat assembly (SISA) specified in this
final rule is slightly different from the proposed
[[Page 39239]]
SISA in four ways: aspects of the representative vehicle seat cushion
(characteristics of the seat foam), the height of the seat back,
location of the child restraint anchorages and seat belts, and vertical
position of the door and armrest. These changes were made to make it
easier to source foam, and to reflect real-world vehicle seats more
accurately. The changes align with the November 2, 2020 NPRM that
proposes to update FMVSS No. 213's frontal impact test seat
assembly.\31\ Stiffening structures were also added to the sliding seat
to minimize vibrations in compliance testing.
---------------------------------------------------------------------------
\31\ 85 FR 69388, supra.
---------------------------------------------------------------------------
The tolerance in the relative velocity (V0)
between the sliding seat and the door assembly at time of initial
contact (T0) is reduced in the final rule from the proposed
31.3 0.8 km/h to 31.3 0.64 km/h to improve
repeatability and reproducibility of the test.
The NPRM proposed that the test platform velocity during
the time of interaction of the door with the CRS would be no greater
than V0 and not less than V0-1 km/h. This final
rule specifies the test platform velocity as no lower than 2.5 km/h
less than its velocity at time = T0. This change provides
more flexibility to different test facilities to meet the test
specifications while maintaining satisfactory test repeatability and
reproducibility.
This final rule includes specifications for a relative
door velocity corridor (the velocity of the simulated door assembly
relative to the sliding seat) to improve the repeatability and
reproducibility of the test procedure. NHTSA requested comment in the
NPRM on the merits of a corridor and decided, after reviewing the
comments, that a corridor increases the repeatability and
reproducibility of the test when different types of sled systems \32\
are used.
---------------------------------------------------------------------------
\32\ There are acceleration and deceleration type sled systems.
An acceleration sled is accelerated from rest to a prescribed
acceleration profile to simulate the occupant compartment
deceleration in a crash event. In comparison, a deceleration sled is
first accelerated to a target velocity and then is decelerated to a
prescribed deceleration profile to simulate the same event.
---------------------------------------------------------------------------
NHTSA tentatively believed in the NPRM that CRS
performance would not be affected if a CRS were attached to the SISA by
a seat belt or by the child restraint anchorage system, assuming that a
seat belt would be routed through a belt path near to where the
anchorage attachment points are located. NHTSA thus proposed to test
child restraints by attaching them only by the child restraint
anchorage system, and requested comment on the issue. Several
commenters supported testing with the seat belt attachment in addition
to the child restraint anchorage system attachment. After considering
the comments, and after observing that some newer child restraint
designs have belt paths no longer near the CRS's anchorage attachment
points, NHTSA has included a test configuration using a Type 2 seat
belt (lap and shoulder belt) with the CRS's top tether attached, if
provided.
The NPRM proposed using the 12-month-old CRABI dummy to
test child restraints recommended for children weighing 5 to 10 kg (11
to 22 lb) and the Q3s dummy (representative of a 3-year-old child) to
test child restraints for children weighing 10 to 18.1 kg (22 to 40
lb). After reviewing comments on this issue, NHTSA has decided to raise
the 10 kg (22 lb) dividing line to 13.6 kg (30 lb) so that infant
carriers would not be subject to testing with the Q3s 3-year-old
dummy.\33\ Testing with the Q3s does not make sense as the dummy is too
large to fit an infant carrier and is not representative of the
children for whom the restraint is recommended. Testing infant carriers
with only the CRABI 12-month-old dummy better aligns the standard's
test requirements with real world use of the restraints.\34\
---------------------------------------------------------------------------
\33\ An infant carrier is a rear-facing CRS designed to be
easily used inside and outside of the vehicle. They typically are
sold for use by children in a weight range from newborn to 18.5 kg
(40 lb). An infant carrier is designed to be easily removed from the
vehicle and has a carrying handle that allows caregivers to tote the
infant outside of the vehicle without having to remove the child
from the restraint system. Some come with a base that stays inside
the vehicle, enabling a simple means of reattaching the carrier when
it is used as a CRS. This change is consistent with the November 2,
2020 NPRM on FMVSS No. 213's frontal crash test requirements.
\34\ This statement assumes the carriers are not designed to
accommodate child weights over 13.6 kg (30 lb).
---------------------------------------------------------------------------
II. Safety Need
The motor vehicle occupant fatality rate among children 3-years-old
\35\ and younger has declined from 4.5 in 1975 to 1.1 in 2019 (per
100,000 occupants). This decline in fatality rate is partially
attributed to the increased use of child restraint systems. The 2019
National Survey of the Use of Booster Seats (NSUBS) found that
restraint use in the rear row (excluding third or further rows) was 98
percent for children less than 1-year-old, 95 percent for 1- to 3-year-
old, and 88 percent for 4- to 7-year-old.\36\
---------------------------------------------------------------------------
\35\ As used in this document, ``children 3-years-old and
younger'' includes children up to the day before they turn 4-years-
old.
\36\ Enriquez, J. (2021, May). The 2019 National Survey of the
Use of Booster Seats (Report No. DOT HS 813 033). National Highway
Traffic Safety Administration. https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813033.
---------------------------------------------------------------------------
According to the 2019 FARS data files, there were 36,096 persons
killed in motor vehicle crashes in 2019, 177 of whom were children aged
3 and younger killed in passenger vehicle crashes. Among the 177 child
occupant fatalities, 44 (25 percent) were unrestrained, 7 (4 percent)
were restrained by vehicle seat belts, 111 (63 percent) were restrained
in CRSs, and 13 (7 percent) had unknown restraint use.\37\
---------------------------------------------------------------------------
\37\ Children, Traffic Safety Facts--2009 data, DOT HS 811 387,
NHTSA, https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/811387.
---------------------------------------------------------------------------
In 1996, the agency estimated the effectiveness of CRSs and found
the devices to reduce fatalities by 71 percent for children younger
than 1-year-old and by 54 percent for toddlers 1- to 4-years-old in
passenger vehicles.\38\ For this rulemaking, the agency updated the
1996 effectiveness estimates by conducting a similar analysis using the
FARS data files for the years 1995-2009.\39\ In the updated
analysis,\40\ only non-rollover frontal and side crashes of passenger
cars and LTVs were considered. CRS effectiveness was estimated for each
crash mode. Due to small sample size of unrestrained children less than
1-year-old, the 0- to 1-year-old age group was combined with the 1- to
3-year-old age group for determining CRS effectiveness for each crash
mode. The results indicate that in non-rollover frontal crashes, CRSs
currently in use are 53 percent effective in preventing fatalities
among children 0- to 3-years-old and 43 percent effective among
children 4- to 7-years-old. In non-rollover side crashes, CRSs
currently in use are 42 percent effective in preventing fatalities
among 0- to 3-year-old children and 51 percent effective among 4- to 7-
year-old children.
---------------------------------------------------------------------------
\38\ ``Revised Estimates of Child Restraint Effectiveness,''
Research Note, supra.
\39\ Details of the analysis method are provided in the
supporting technical document in the docket for the NPRM.
\40\ Details of the updated analysis are provided in the
supporting technical document in the docket for the NPRM.
---------------------------------------------------------------------------
NHTSA estimates that the lives of 325 children 3-years-old and
younger were saved in 2017 due to the use of child restraint
systems.\41\
---------------------------------------------------------------------------
\41\ National Center for Statistics and Analysis (2019, March).
Lives saved in 2017 by restraint use and minimum-drinking-age laws
(Traffic Safety Facts Crash[middot]Stats. Report No. DOT HS 812
683). Washington, DC: National Highway Traffic Safety
Administration. Available at: https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/8126834.
---------------------------------------------------------------------------
Failure to use proper occupant restraints is a significant factor
in a large
[[Page 39240]]
number of child occupant fatalities resulting from motor vehicle
crashes. In addition, fatalities among children properly restrained in
child restraints are often attributed to the severity of the crash.
Sherwood \42\ examined the FARS database for the year 2000 and
determined that there were 621 child occupant fatalities in the age
range of 0 to 5 years. Among these 621 fatalities, 143 (23 percent)
children were reported to be in child restraints. Detailed police
reports were available for 92 of the 143 fatally injured children
restrained in CRSs. Sherwood examined these 92 police reports and
determined that half of the 92 fatalities were in un-survivable
crashes, 12 percent of the fatalities were judged to result from gross
misuse of child restraints, 16 percent in non-catastrophic side
impacts, and 13 percent in non-catastrophic frontal impacts. Sherwood
noted that side impacts accounted for the largest number of fatalities
(40 percent), and in all side impact crashes involving child
fatalities, there was vehicle intrusion at the child's seating
position.
---------------------------------------------------------------------------
\42\ Sherwood, C.P., Ferguson, S.A., Crandall, J.R., ``Factors
Leading to Crash Fatalities to Children in Child Restraints,'' 47th
Annual Proceedings of the Association for the Advancement of
Automotive Medicine (AAAM), September 2003.
---------------------------------------------------------------------------
In-Depth Study of Fatalities Among Child Occupants
The agency further examined the real-world crash databases managed
by the agency (FARS (2015-2019) and the National Automotive Sampling
System-Crashworthiness Data System (NASS-CDS) 2001-2015) to better
understand fatalities to children restrained in child restraints when
involved in side crashes.
First, NHTSA categorized the crash cases involving children (0- to
12-years-old) seated in rear seating positions, by restraint use, crash
type, and child age. See Tables 5 and 6, below.
Table 5--Average Annual Crash Fatalities Among Children 0- to 12-Years-Old in Rear Seating Positions of Light
Passenger Vehicles Categorized by Restraint Type and Age
[FARS 2015-2019]
----------------------------------------------------------------------------------------------------------------
Age (years)
Restraint ---------------------------------------------------------------- Total
Under 1 1-3 4-7 8-12
----------------------------------------------------------------------------------------------------------------
None............................ 7.2 24.6 50.6 67.0 149.4
Adult Belt...................... 0.8 8.2 36.8 77.0 122.8
CRS............................. 40.6 96.6 69.2 6.4 212.8
Unknown......................... 3.2 9.4 15.0 12.4 40.0
Other........................... 0.0 0.2 0.6 0.4 1.2
-------------------------------------------------------------------------------
Total....................... 51.8 139.0 172.2 163.2 526.2
----------------------------------------------------------------------------------------------------------------
Annually on average between 2015 and 2019, there were 526 crash
fatalities among children 0- to 12-years-old seated in rear seating
positions of light vehicles. Among these fatalities, on average 213 (40
percent) were children restrained in CRSs (137 were 0- to 3-years-old
and 76 were 4- to 12-years-old). Nearly 64 percent of the CRS
restrained child fatalities were children 0- to 3-years-old.
As shown in the last column of Table 6, among the 213 fatalities of
children 0- to 12-years-old restrained in rear seats of light passenger
vehicles and in CRSs, approximately 31 percent occurred in frontal
crashes, 25 percent in side crashes, 22 percent in rollovers, and 19
percent in rear crashes. Approximately 55 percent of side impact
fatalities (28.8/52.2) were in near-side impacts. (``Far-side''
position means the outboard seating position on the opposite side of
the point of impact or the center seating position.)
---------------------------------------------------------------------------
\43\ The 2005-2009 FARS analysis presented in the NPRM, showed
31 percent fatalities of children 0- to 12-years-old restrained in
rear seats of light passenger vehicles and in CRSs were in side
impact. The 2015-2019 FARS analysis shows only 24.5 percent of
fatalities in side impacts, however, the difference in the figures
are attributed to the changing available variables in FARS not a
decrease in side impact fatalities. The 2005-2009 FARS analysis was
done using ``IMPACT2 (most damaged area)'' while the 2015-2019 was
done using ``IMPACT1 (area of initial contact), as IMPACT2 was
retired.
Table 6--Average Annual Crash Fatalities Among Children 0- to 12-Years-Old in Rear Seating Positions of Light Passenger Vehicles and Restrained in CRSs
by Crash Mode and Age
[FARS 2015-2019] \43\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Age (years)
Crash mode ---------------------------------------------------------------- Total Percent total
<1 1-3 4-7 8-12
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rollover................................................ 8.0 21.8 15.4 1.6 46.8 22.0
Front................................................... 13.6 30.8 21.4 0.8 66.6 31.3
Side.................................................... 10.2 23.4 16.2 2.4 52.2 24.5
Near-side............................................... 6.2 11.6 9.2 1.8 28.8 13.5
Far-side................................................ 3.8 11.4 6.8 0.6 22.6 10.6
Unknown-side............................................ 0.2 0.4 0.2 0.0 0.8 0.4
Rear.................................................... 7.8 17.0 14.0 1.6 40.4 19.0
Other................................................... 0.4 2.0 1.0 0.0 3.4 1.6
Unknown................................................. 0.6 1.6 1.2 0.0 3.4 1.6
-----------------------------------------------------------------------------------------------
Total............................................... 40.6 96.6 69.2 6.4 212.8 100.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
[[Page 39241]]
Of the side impact crash fatalities among CRS restrained children
0- to 12-years-old in rear seating positions, nearly 62 percent of near
side fatalities ((6.2 + 11.6)/28.8) were to children under the age of
4.
In-Depth Study of Injuries to Child Occupants in Motor Vehicle Crashes
In 2010, the agency published an analysis of the NASS--General
Estimates System (GES) data for the years 1999-2008 to better
understand injuries to children in motor vehicle traffic crashes.\44\
The analysis was conducted for three different child age groups (<1-
year-old, 1- to 3-years-old, and 4- to 7-years-old) and for different
crash modes (rollover, front, side, and rear). The analysis indicated
that CRSs are effective in reducing incapacitating injuries in all
three child age groups examined and in all four crash modes. The
analysis found that rollover crashes accounted for the highest rate of
incapacitating injuries, with the incidence rate among unrestrained
children (26 percent) being nearly 3 times that for children restrained
in CRSs (9 percent). In near-side impact crashes, unrestrained children
(incidence rate = 8 percent) were 8 times more likely to sustain
incapacitating injuries than children in CRSs (incidence rate = 1
percent).
---------------------------------------------------------------------------
\44\ Hanna, R., ``Children Injured in Motor Vehicle Traffic
Crashes,'' DOT HS 811 325, NHTSA, May 2010, http://www-nrd.nhtsa.dot.gov/Pubs/811325.pdf, last accessed on July 2, 2012.
---------------------------------------------------------------------------
The agency analyzed NASS-CDS for the years 2001-2015 to obtain
annual estimates of moderate or higher severity injuries (MAIS 2+
injuries) among children of different ages in different restraint
environment and crash modes. See Table 7 and 8.
Table 7--Average Annual Estimates of 0- to 12-Years-Old Children With MAIS 2+ Injuries in Rear Seating Positions of Light Passenger Vehicles Involved in
Motor Vehicle Crashes by Restraint Type
[NASS-CDS 2001-2015]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Age (years)
Restraint ---------------------------------------------------------------- Total Percent of
Under 1 1-3 4-7 8-12 total
--------------------------------------------------------------------------------------------------------------------------------------------------------
None.................................................... 15 94 530 575 1,214 20.0
Adult Belt.............................................. 0 91 489 860 1,440 23.8
CRS..................................................... 181 731 504 36 1,452 24.0
Unknown if Used......................................... 1 28 323 146 498 8.2
-----------------------------------------------------------------------------------------------
Total............................................... 378 1,675 2,350 1,653 6,056 100.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
Between 2001 and 2015 on average annually there were an estimated
6,056 twelve and younger children with MAIS 2 + injuries seated in the
rear seats of light passenger vehicles with 2,053 of these injured
occupants being younger than 4- years-old. Approximately 1,452 CRS
restrained children 12-years-old and younger sustained MAIS 2+injuries,
among which 912 (63 percent) were children younger than 4-years-old and
504 (35 percent) were 4- to 7-year-old children.
The NASS-CDS 2001-2015 data files were further analyzed to
determine crash characteristics. Table 8 presents the average annual
estimates of 0- to 12-year-old children with MAIS 2+ injuries in rear
seating positions of light passenger vehicles. Approximately 38 percent
of the children were injured in frontal crashes, 32 percent in side
crashes, 24 percent in rollover crashes and 5 percent in rear crashes.
Table 8--Average Annual Estimates of 0- to 12-Years-Old Children With MAIS 2+ Injuries in Rear Seating Positions of Light Passenger Vehicles Involved in
Motor Vehicle Crashes by Crash Mode
[NASS-CDS 2001-2015]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Age (years)
Crash mode ---------------------------------------------------------------- Total Percent of
<1 1-3 4-7 8-12 total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rollover................................................ 13 150 396 543 1,102 23.9
Front................................................... 62 329 710 658 1,759 38.2
Side.................................................... 46 373 691 387 1,497 32.5
Near-Side........................................... 31 276 330 260 897 19.5
Far-Side............................................ 11 58 360 126 555 12.1
Unknown-Side........................................ 4 39 1 1 45 1.0
Rear.................................................... 78 76 49 29 232 5.0
Other................................................... 0 14 0 0 14 0.3
-----------------------------------------------------------------------------------------------
Total............................................... 199 942 1,846 1,617 4,604 100.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
To better understand the crash characteristics of children
restrained in child restraints, a similar analysis as that shown in
Table 8 was conducted except that only the cases where the children
were restrained in CRSs were included in the analysis. The results are
presented in Table 9.
[[Page 39242]]
Table 9--Average Annual Estimates of 0- to 12-Years-Old CRS Restrained Children With MAIS 2+ Injuries in Rear Seating Positions of Light Passenger
Vehicles Involved in Motor Vehicle Crashes by Crash Mode
[NASS-CDS 2001-2015]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Age (years)
Crash mode ---------------------------------------------------------------- Total Percent of
Under 1 1-3 4-7 8-12 total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rollover................................................ 12 60 102 0 174 12.0
Front................................................... 55 293 233 18 599 41.2
Side.................................................... 42 323 139 18 522 35.9
Near-side........................................... 31 272 44 18 336 25.1
Far-side............................................ 11 51 95 0 157 10.8
Rear.................................................... 74 54 31 0 159 10.29
-----------------------------------------------------------------------------------------------
Total............................................... 183 730 505 36 1,454 100.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
For MAIS 2+ injured 12-years-old and younger child occupants in
passenger vehicles restrained in CRSs in rear seating positions, 41
percent of the injuries were in frontal crashes, 36 percent in side
crashes, 12 percent in rollovers, and 10 percent in rear crashes. About
64 percent (336/522) of the occupants in side crashes were in near-side
impacts.
In the above analyses, some of these injuries and fatalities
involved children in seats that were incorrectly used. However, NHTSA
does not have complete data on the number accidents that involved
misuse because accident databases do not generally collect data on how
child restraints were used.
III. Statutory Mandate
Subtitle E of the ``Moving Ahead for Progress in the 21st Century
Act'' (MAP-21), Public Law 112-141 (July 6, 2012),\45\ included Section
31501(a), which stated that, not later than two years after the date of
enactment of the Act, the Secretary (NHTSA by delegation) shall issue a
final rule amending Federal Motor Vehicle Safety Standard No. 213 to
improve the protection of children seated in child restraint systems
during side impact crashes.
---------------------------------------------------------------------------
\45\ Subtitle E is entitled ``Child Safety Standards.''
---------------------------------------------------------------------------
This final rule accords with MAP-21 and implements Congress's
intent to implement a side impact standard for child restraints. In
2004, NHTSA informed Congress \46\ that, while enhanced side impact
protection for children in child restraints was a priority for NHTSA,
NHTSA had initiated a side impact rulemaking in response to the
Transportation Recall Enhancement, Accountability and Documentation
(TREAD) Act but found the extent of the uncertainties prevented
adoption of a side impact performance test for CRSs.\47\ NHTSA informed
Congress when the agency withdrew the rulemaking that NHTSA would
continue its efforts to obtain detailed side crash data identifying
specific injury mechanisms involving children and would work toward
developing countermeasures using test dummies, including the European
Q3 dummy then available, for improved side impact protection.
---------------------------------------------------------------------------
\46\ NHTSA Report to Congress, ``Child Restraint Systems,
Transportation Recall Enhancement, Accountability, and Documentation
Act,'' February 2004. www.nhtsa.gov/nhtsa/announce/NHTSAReports/TREAD.pdf.
\47\ Advance Notice of Proposed Rulemaking, 67 FR 21836, May 1,
2002.
---------------------------------------------------------------------------
In March 2011, NHTSA's Vehicle Safety and Fuel Economy Rulemaking
and Research Priority Plan 2011-2013, announced the agency's intention
to issue an NPRM in 2012 on child restraint side impact protection.\48\
NHTSA stated in the plan that it was planning to ``[p]ropose test
procedures in FMVSS No. 213 to assess child restraint performance in
near-side impacts. Amend Part 572 to add the Q3s dummy, the 3-year-old
side impact version of the Q-series of child dummies.''
---------------------------------------------------------------------------
\48\ Docket No. NHTSA-2009-0108-0032.
---------------------------------------------------------------------------
MAP-21 was enacted soon thereafter, with a short deadline for
issuance of a final rule. Given the context of NHTSA's work in this
area, NHTSA has interpreted Subtitle E as directing NHTSA to apply the
knowledge gained since its 2004 report to Congress to initiate and
complete the side impact regulation as the agency had planned. There
were no child test dummies other than the Q3s available when MAP-21 was
enacted that were proven sufficiently durable and reliable for use in
the FMVSS No. 213 side impact test.\49\ There was not enough time to
develop and validate a different test procedure, or new child side
impact test dummies, within the time constraints of Subtitle E.
---------------------------------------------------------------------------
\49\ There are still no child test dummies that are suitable for
use in a side impact FMVSS other than the Q3s.
---------------------------------------------------------------------------
MAP-21 required a final rule ``amending FMVSS No. 213,'' which
NHTSA has interpreted to mean that the rulemaking must be conducted in
accordance with the National Traffic and Motor Vehicle Safety Act (49
U.S.C. 30101 et seq.) (Safety Act). NHTSA has developed a standard that
will improve the protection of children seated in child restraint
systems during side impacts, in accordance with MAP-21, while meeting
the criteria of Section 30111 of the Safety Act. Standard No. 213a
meets the need for safety, is stated in objective terms, and is
reasonable, practicable, and appropriate for the CRSs for which it is
prescribed. There are technical and practical reasons for applying the
dynamic side impact test only to CRSs designed to seat children in a
weight range that includes weights up to 18.1 kg (40 lb).
For one, there is no side impact dummy representative of children
weighing more than 40 lb that is proven to provide the test
measurements required of a dummy used in the Federal motor vehicle
safety standards. Without an appropriate test dummy, the data from a
dynamic test would not provide a meaningful assessment of the
performance of the CRS in protecting children of weights above 18.1 kg
(40 lb). Without a valid test dummy, CRSs for heavier children may
``pass'' a side impact test with the Q3s, but the Q3s would not
meaningfully assess the performance of the CRS in protecting the
heavier child. Raising the limit above 40 lb could engender a false
sense of security that a restraint adequately protects the heavier
children when, in fact, without a heavier test dummy, the standard
would not be adequately assessing the restraint's protection of these
children. NHTSA believes Congress was aware of this limitation on the
availability of test dummies when it enacted MAP-21, and did not want
[[Page 39243]]
NHTSA to apply the new standard to a subset of CRSs that could not be
sufficiently assessed for their performance in protecting a child in a
side impact. Moreover, it does not seem sensible to require
manufacturers to ensure their CRSs comply with the standard tested with
the Q3s if the child restraints are not intended for, and will not be
used with, children of the size represented by the Q3s. Thus, NHTSA
does not consider it reasonable or appropriate \50\ to apply this final
rule to child restraints that are not recommended for children weighing
between 13.6 kg (30 lb) and 18.1 kg (40 lb).
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\50\ 49 U.S.C. 30111(b)(3).
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In addition, NHTSA drafted this final rule recognizing that
children weighing more than 18.1 kg (40 lb) seated in a child restraint
will be seated high enough to benefit from a passenger vehicle's side
curtain air bags.\51\ In the November 2, 2020 NPRM proposing to amend
FMVSS No. 213, supra, NHTSA proposed requiring booster seats to be
labeled only for children weighing more than 18.1 kg (40 lb). If,
because of that label, children are kept in safety seats until they are
at least 18.1 kg (40 lb), they will be seated until that time in a CRS
that will be certified to the side impact protection requirements of
FMVSS No. 213a. Also, when they transition to a booster seat (or a
child restraint with an internal harness intended for children weighing
more than 18.1 kg (40 lb)), such booster seat or child restraint will
lift them high enough to be protected by the vehicle's side curtain air
bags. That label will help ensure that children will remain in car
seats longer and will only use booster seats when they are tall enough
to take advantage of a vehicle's side protection countermeasures.
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\51\ Children weighing more than 18.1 kg (40 lb) restrained in
CRSs would have a seated height similar to the height of a 5th
percentile adult female. The vehicle's side curtain air bags are
designed to protect occupants, including those of the size of a 5th
percentile female, in side impacts and rollovers.
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IV. Guiding Principles
In addition to the considerations already discussed, the following
principles also guided NHTSA's decisions in developing this final rule.
1. There is a safety need for this rulemaking notwithstanding the
estimated effectiveness of child restraints in side impacts.\52\ Child
restraint safety in side impacts can be increased. NHTSA has observed
that increasing numbers of CRSs appear to have more side structure
coverage (CRS side ``wings'') and side padding than before.\53\ Because
the design of the side wings and stiffness of the padding are factors
that affect the containment of the child dummy and the injury measures,
NHTSA considers the side wing coverage and increased padding to be
overall positive developments. However, because FMVSS No. 213 did not
have a side impact test, a quantifiable assessment of the protective
qualities of the features was heretofore not possible. Further, testing
NHTSA conducted in developing this final rule indicate that not all
side wings and padding protect the same, and in some cases, ``more'' of
a countermeasure (padding, structure) was not necessarily ``better.''
This final rule establishes performance requirements that ensure that
the wings, padding, padding-like features, or other countermeasures
employed to provide protection in side impacts will be engineered to
attain at least a minimum threshold of performance that will reduce
unreasonable risk of injury or fatality in side impacts. For CRS
designs that have not yet incorporated side impact protection features,
this final rule ensures they will.
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\52\ NHTSA estimates that CRSs are already 42 percent effective
in preventing death in side crashes of 0- to 3-year-old children.
Supra.
\53\ SafetyBeltSafe U.S.A. https://web.archive.org/web/20131012130527/http://www.carseat.org/Pictorial/InfantPict,1-11.pdf
and https://web.archive.org/web/20120915194832/http://www.carseat.org/Pictorial/3-Five-%20Point-np.pdf.
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2. In making regulatory decisions on possible enhancements to CRS
performance, NHTSA bears in mind the consumer acceptance of cost
increases to a highly effective item of safety equipment.\54\ Any
enhancement that would significantly raise the price of the restraints
could potentially have an adverse effect on the sales and use of this
equipment. The net effect on safety could be negative if the effect of
sales losses exceeds the benefit of the improved performance of the
restraints that are purchased, or if older child restraints that are
not designed to meet current requirements were reused. Thus, to
maximize the total safety benefits of its efforts on FMVSS No. 213,
NHTSA must balance those improvements against impacts on the price of
restraints. In addition, NHTSA must also consider the effects of
improved performance on the ease of using child restraints. If the use
of child restraints becomes overly complex or unwieldy, the misuse and
nonuse of child restraints could increase, and the benefits engineered
into the CRS not realized in the real world.
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\54\ Child restraint systems are highly effective in reducing
the likelihood of death or serious injury in motor vehicle crashes.
NHTSA estimates that, for children less than 1-year-old, a child
restraint can reduce the risk of fatality by 71 percent when used in
a passenger car and by 58 percent when used in a pickup truck, van,
or sport utility vehicle (light truck). ``Revised Estimates of Child
Restraint Effectiveness,'' Research Note, National Center for
Statistics and Analysis (NCSA) of the National Highway Traffic
Safety Administration (NHTSA), DOT HS 96855, December 1996. Child
restraint effectiveness for children between the ages 1- to 4-years-
old is 54 percent in passenger cars and 59 percent in light trucks.
Id.
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3. NHTSA is guided by the principles for regulatory decision-making
set forth in Executive Order (E.O.) 12866, ``Regulatory Planning and
Review,'' and E.O. 13563, ``Improving Regulation and Regulatory
Review.'' NHTSA's assessment of the net effect on safety of this
rulemaking was limited in some respects, however. Data are sparse on
side crashes resulting in severe injuries or fatalities to children in
CRSs. Data indicate that side crashes resulting in fatalities to
children in CRSs mainly occur in very severe, un-survivable side impact
conditions. A dynamic test involving a very high velocity impact may
not be reasonable if ultimately the crash replicated were basically un-
survivable, or if the standard's requirements were impracticable or
resulted in CRSs that could not be used as a practical matter or used
correctly. Another limiting factor was the absence of information
comparing the real-world performance of ``good'' performing CRSs versus
``poor'' performing CRSs. Without these data, NHTSA had to use test
data and injury curves to determine the effectiveness of possible
countermeasures (e.g., side wings with strategically-placed energy-
absorbing padding).
V. Overview of the NPRM and Comments Received
a. Overview of the NPRM
NHTSA published the NPRM for this final rule on January 28, 2014
(79 FR 4570, Docket No. NHTSA-2014-0012). The NPRM proposed to amend
FMVSS No. 213 to require CRSs designed to seat children in a weight
range that includes weights up to 18.1 kg (40 lb) to meet side impact
performance requirements in new FMVSS No. 213a, in addition to the
requirements for frontal protection established in FMVSS No. 213.\55\
We
[[Page 39244]]
reopened the comment period on June 4, 2014, in response to a petition
from the Juvenile Products Manufacturers Association (JPMA).\56\
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\55\ NHTSA considered incorporating the side impact requirements
into FMVSS No. 213, rather than in FMVSS No. 213a, but decided
against doing so. MAP-21 directed NHTSA to undertake side and
frontal impact test rulemakings in the same timeframe, with each
involving different compliance schedules and different test dummies.
NHTSA decided that combining the side and frontal test rulemakings
into one standard (with each encompassing entirely new sled test
systems and dynamic test requirements), could have made the
revisions difficult to understand, particularly with the new
requirements for the frontal and side tests becoming effective on
different dates. The agency decided to establish the side impact
requirements separately in FMVSS No. 213a for clarity and plain
language purposes.
\56\ The comment period was reopened until October 2, 2014 (79
FR 32211). JPMA petitioned to provide more time for child restraint
manufacturers to obtain the Q3s dummy from the dummy manufacturer,
arrange with test labs to evaluate their CRSs with it, conduct
testing, and comment on the proposal.
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NHTSA proposed performance requirements that child restraints must
meet when tested dynamically in a sled test replicating a side crash.
The NPRM proposed that child restraints would be tested while attached
to a standardized seat assembly. The sled test \57\ procedure was
designed to replicate a two-vehicle side crash depicted in the moving
deformable barrier (MDB) test of FMVSS No. 214 (striking vehicle
traveling at 48.3 km/h (30 mph)) impacting the struck vehicle traveling
at 24.1 km/h (15 mph). The proposed sled test simulated a near-side
side impact of a small passenger car. FMVSS No. 213a's side impact test
represents a crash with a change of velocity of approximately 19 mph.
NHTSA's analysis of field data (NASS-CDS 1995-2009) found that 92
percent of near-side crashes for restrained children (0- to 12-years-
old) involved a change in velocity of 19 mph or lower.\58\
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\57\ The sled test was based on an acceleration sled system. An
acceleration sled is accelerated from rest to a prescribed
acceleration profile to simulate the occupant compartment
deceleration in a crash event. In comparison, a ``deceleration
sled'' is first accelerated to a target velocity and then is
decelerated to a prescribed deceleration profile to simulate the
same event. The proposed acceleration sled was originally developed
by the Takata Corporation. (Literature on development of the FMVSS
No. 213a sled test sometimes refers to the sled as the ``Takata''
system.)
\58\ Obtained from an analysis of the National Automotive
Sampling System--Crashworthiness Data System (NASS-CDS) data files
for the years 1995-2009 for restrained children 0- to 12-years-old
in all restraint environments including seat belts and CRS. Details
of the analysis are provided in the technical report in the docket
for the NPRM (Docket No. NHTSA-2014-0012).
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NHTSA examined data from FMVSS No. 214 MDB compliance tests to
identify kinematic characteristics of the vehicle test to replicate in
the sled test environment, and proposed characteristics relating to the
acceleration profile of the sliding seat (representing the struck
vehicle acceleration), the door velocity at time of contact with the
sliding seat (to represent the struck vehicle door velocity), and the
impact angle of the door with the sliding seat (to replicate the
longitudinal component of the direction of force). Comments were
requested \59\ on whether a relative door velocity profile (the
velocity of the door relative to the sliding seat) should be specified
to improve the reproducibility of the test procedure using different
types of sled systems.
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\59\ 79 FR at 4585.
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NHTSA proposed to apply FMVSS No. 213a to CRSs manufactured and
offered for sale for children up to 18.1 kg (40 lb). The NPRM proposed
that child restraint systems with integral internal harnesses (car
seats or safety seats) would be attached to the side impact seat
assembly (SISA) using the child restraint anchorage system on the SISA
(including the top tether, if one were provided).\60\ Comments were
requested on whether car seats should also be tested when attached by a
Type 2 belt and top tether. The NPRM proposed that child restraints
that do not have connectors designed to attach to a child restraint
anchorage system would be tested using a Type 2 belt (e.g., booster
seats recommended for children weighing less than 18.1 kg (40 lb)
\61\).
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\60\ The child restraint anchorage system is commonly referred
to as the LATCH system (``Lower Anchors and Tethers for Children'').
\61\ This proposal predated a November 2, 2020 NPRM in which
NHTSA proposed prohibiting booster seats from being recommended for
children weighing less than 18.1 kg (40 lb). If the November 2020
proposal is adopted, the FMVSS No. 213a provision would be moot.
---------------------------------------------------------------------------
NHTSA proposed that child restraint systems recommended for
children with weights in the 10 kg to 18.1 kg (22 lb to 40 lb) range
would be tested on the SISA with the Q3s test dummy.\62\ Child
restraints would have to meet injury criteria (expressed in terms of
HIC15 \63\ and chest deflection) when tested with the Q3s dummy. These
criteria allow a quantitative evaluation of the effectiveness of the
CRS, and the ability of the CRS to prevent or attenuate head and chest
impact with the intruding door. CRSs recommended for children with
weights that include weights up to 10 kg (22 lb) would be tested with
the 12-month-old CRABI dummy (49 CFR part 572, subpart R). Because the
CRABI dummy is designed for frontal and not side impacts, the NPRM
proposed that the CRABI would be used only to measure the containment
capability of the child restraint (the ability of the restraint to
prevent the dummy's head from contacting the intruding door of the
SISA). The dummy's head and chest instrumentation would not be
leveraged since the dummy was not designed to assess crash forces in
side impacts.
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\62\ The proposed weight ranges described in this paragraph have
been adjusted in this final rule. NHTSA is adopting a 13.6 kg (30
lb) cut off instead of a 10-kg (22-lb) cut off.
\63\ A measurement of the head injury criterion that is based on
the integration of resultant head acceleration over a 15-millisecond
duration.
---------------------------------------------------------------------------
The NPRM also proposed requiring child restraints to meet
structural integrity and other performance requirements in FMVSS No.
213. When a CRS is dynamically tested with the appropriate ATD, there
should not be any complete separation of any load-bearing structural
element \64\ of the CRS or any partial separation exposing surfaces
with sharp edges that may contact an occupant. These requirements would
reduce the likelihood that a child using the CRS would be injured by
the collapse or disintegration of the system, projectiles coming from a
seat involved in a side crash or by contact with the interior of the
passenger compartment or with components of the CRS. NHTSA notes that
while some CRS structures have not been considered load-bearing
structural elements in frontal testing (FMVSS No. 213) by NHTSA, these
same CRS structures may be considered load-bearing structural elements
in side impact testing (FMVSS No. 213a).
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\64\ NHTSA interprets load bearing structure to mean a structure
that: (1) transfers energy from the SISA and/or door to the CRS
(e.g., installation components or CRS areas that contact the
intruding door), or (2) transfers energy from the CRS to the
occupant or vice versa (e.g., belts and components to restrain the
child, CRS surfaces or parts transferring energy to the occupant).
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Injury from contacting protrusions, such as the pointed ends of
screws mounted in padding, would be prevented in a similar manner as
that specified for the frontal crash test in FMVSS No. 213. The height
of such protrusions would be limited to not more than 0.375 inches
above any immediately adjacent surface. Also, contactable surfaces
(surfaces contacted by the head or torso of the ATD) would not be
permitted to have an edge with a radius of less than 6.35 mm (0.25
inches), even under padding. Padding will compress in an impact and the
load imposed on the child would be concentrated and potentially
injurious.
The NPRM discussed NHTSA's testing of CRS models representative of
seats available then in the market. NHTSA had tested twelve forward-
facing and five rear-facing child restraints with the Q3s dummy. The
Q3s measured HIC15 greater than 570 in seven of the twelve forward-
facing CRSs tested. The Q3s measured chest deflection greater than 23
mm in three of the twelve forward-facing CRSs tested. The Q3s measured
both HIC15 greater than 570 and chest deflection greater than 23 mm in
three of the tests of the forward-facing CRSs. For the five
[[Page 39245]]
rear-facing CRSs tested with the Q3s, the results of the fleet tests
showed that the Q3s measured HIC15 greater than 570 in three of the
five rear-facing CRSs tested, and chest deflection greater than 23 mm
in two of the five tests. The Q3s measured both HIC15 greater than 570
and chest deflection greater than 23 mm in one of the five rear-facing
CRSs tested. NHTSA tested 12 rear-facing CRSs with the CRABI to
estimate the performance of the fleet. Using head-to-door contact as
the performance criterion in the fleet tests, the results showed that
the CRABI had head contact only with one child restraint (one out of
the twelve models tested).
b. Summary of the Comments
NHTSA received 29 comments on the proposal.\65\ Commenters included
child restraint manufacturers (Dorel Juvenile Group, Graco Children's
Products, Britax Child Safety, Inc UppaBaby, Safeguard/IMMI), the
Juvenile Products Manufacturers Association (JPMA); consumer advocates
(Safe Ride News, Safe Kids Worldwide, Advocates for Highway and Auto
Safety, Consumers Union \66\); the National Transportation Safety
Board; research bodies and testing organizations (Insurance Institute
for Highway Safety (IIHS), University of Michigan Transportation
Research Institute (UMTRI), MGA Research Corporation, ARCCA, Inc., the
Transport Research Laboratory; a supplier of honeycomb (Plascore), and
members of the general public.
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\65\ The NPRM proposing to add the Q3s dummy specifications to
49 CFR part 572 received comments separately from the NPRM preceding
this final rule. Those comments are fully addressed in the November
3, 2020 final rule (85 FR 69898). They are discussed here to the
extent relevant to this final rule.
\66\ Consumer Union is the Policy and Action Division of
Consumer Reports.
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Overview of the Comments
As summarized below, all but four commenters \67\ strongly
supported the proposed inclusion of a side impact test in FMVSS No.
213. Several commenters expressed views on the types of child
restraints they believed should be subject to FMVSS No. 213a. Many
commenters discussed technical aspects of the proposed test procedure,
such as the repeatability and reproducibility of the dynamic test, the
availability of and characteristics of the seat foam specified for the
SISA, how the tested CRS should be positioned on and attached to the
SISA, and how the Q3s should be positioned in the child restraint,
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\67\ These were UMTRI and three individuals.
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Child restraint manufacturers: All child restraint manufacturers
commenting on the NPRM supported the inclusion of a dynamic side impact
test procedure in FMVSS No. 213, as did JPMA, their industry group.
Some had questions about various issues and many responded to the
questions NHTSA had asked in the preamble to the NPRM. Dorel supported
adopting a test procedure that included an intruding door but believed
that the Q3s dummy exhibited ``artificial forward head movement before
the crash impact'' that places the dummy out of position in relation to
the side wing. Dorel expressed concerns about the repeatability and
reproducibility (R&R) of results from NHTSA's test program, as did
Graco, the latter providing feedback on results of test trials it
conducted comparing the R&R of the proposed side impact test using data
from several different test labs. Graco evaluated potential causes of
variation and recommended ways to improve the sled design to reduce
variation between the labs.
Some CRS manufacturers suggested revisions to technical aspects of
the proposal. Britax believed the United Nations Economic Commission
for Europe Regulation No. 44 \68\ (ECE R.44) foam proposed for use on
the SISA is not readily available and specifying it in FMVSS No. 213a
may create considerable hardship from cost and availability
perspectives. Britax supported the agency's views in the NPRM about
testing and labeling of belt-positioning booster seats. UPPAbaby
recommended against using the Q3s dummy to test rear-facing infant
seats, because, it stated, ``the head of the Q3s exceeds the limit to
which we recommend a child be positioned in our seat.'' UPPAbaby
supported using a lap/shoulder belt to attach car seats to the SISA, in
addition to a child restraint anchorage system. IMMI supported
excluding harnesses from the proposed side impact requirements and
suggested ways to expand the standard's definition of a ``harness.''
JPMA reiterated Dorel's comment about ``artificial forward head
movement'' of the Q3s before impact, reported instances in which the
text in the preamble was inconsistent with proposed regulatory text,
emphasized the importance of reproducibility of test results to the
objectivity of a safety standard, and provided other information.
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\68\ ECE R44--Restraining Devices for Child Occupants of Power
Driven Vehicles (``Child Restraint Systems'').
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Consumer advocates: Safe Ride News (SRN), Safe Kids Worldwide,
Advocates for Highway & Auto Safety (Advocates), and Consumers Union
(CU) supported the proposed rule, while suggesting that NHTSA adopt
further requirements. Several commenters weighed in with responses to
the technical questions in the NPRM. Many concurred that the rule
should only apply to CRSs recommended for children weighing up to 18.1
kg (40 lb) but encouraged NHTSA to develop an ATD (anthropomorphic test
device) (test dummy) representative of older children. SRN, Safe Kids
and CU suggested lead times less than 3 years. Advocates suggested
NHTSA require various warnings on child restraints, such as a warning
on CRSs recommended for children weighing more than 40 lb that ``this
CRS has not been tested in side impacts.'' CU suggested additional
performance criteria for structural integrity and supported testing
CRSs when attached with Type 2 (lap and shoulder) belts. CU believed
that the Q3s is too large to test rear-facing infant seats, and that
NHTSA should consider a planar limit to reduce the potential for the
dummy's head to roll out of the CRS shell in some tests.
Research and testing organizations: The Insurance Institute for
Highway Safety (IIHS) agreed with NHTSA's reasons for not applying
FMVSS No. 213a to CRSs for children weighing more than 18.1 kg (40 lb).
IIHS provided data from its belt fit program showing that children
weighing more than 18.1 kg (40 lb) seated in booster seats are likely
tall enough to benefit from the vehicle side curtain air bag. IIHS and
the University of Michigan Transportation Research Institute (UMTRI)
had concerns about possible dis-benefits from rear-facing restraints
possibly becoming wider in response to meeting FMVSS No. 213a. They
believed wider restraints could potentially indirectly increase injury
risk for restrained children, by, for example, causing older siblings
to graduate prematurely to a booster seat because wider car seats are
harder to fit side-by-side. UMTRI asked whether costs to meet the
proposed standard would be better spent on efforts to restrain
children. The commenter stated that half of pediatric fatalities from
motor vehicle crashes are to unrestrained or improperly restrained
occupants, so rather than modestly improving the side impact protection
for children, efforts should address improving the number of children
using appropriate restraints, enhancing child restraint ease-of-use,
and increasing educational efforts, such as on top tether use. ARCCA
suggested that NHTSA use the Hybrid III 6-year-old and 10-year-old
[[Page 39246]]
frontal crash dummies to assess head containment and structural
integrity.
NTSB: The National Transportation Safety Board (NTSB) supported the
NPRM, believing that the proposed tests encompass the majority of CRSs
because the upper use limit for most small restraint systems extends to
at least 40 pounds and the lower use limit is at or below 40 pounds.
Nonetheless, NTSB urged NHTSA to develop suitable large-sized dummies.
NTSB expressed concern about the kinematic effects of far-side impact
crashes on larger children. NTSB also supported testing CRSs with a
seat belt attachment, in addition to the child restraint anchorage
system attachment. The commenter encouraged NHTSA to consider ease-of-
use improvements for top tethers, and use of a pure lateral
acceleration pulse in the side impact test.
Individuals: Approximately 7 individuals commented on the NPRM.
Most of the individuals supported the proposal, with three opposing.
One of the opposing commenters argued that the injury rates for the
under 1-year-old children are nearly 4 times lower than that for the 1-
to 3-year-old children, so efforts would be better spent increasing the
number of 1- to 3-year-old children who ride rear-facing than on
adopting a side impact standard. The others believed that the estimated
benefits of the proposal are low and do not support the additional
costs to industry or to the consumer.
VI. Response to the Comments (Wide-Reaching Issues)
NHTSA has carefully considered the comments in developing this
final rule. This section discusses the agency's decisions on matters of
general importance. Following this section are discussions relating to
specific topics, such as various technical aspects of the side impact
test procedure, the test dummies, the standard's performance criteria,
and other aspects of FMVSS No. 213a.
a. Are efforts better spent elsewhere on child seat safety?
Almost all of the commenters supported the inclusion of a side
impact test in FMVSS No. 213, but a few expressed concerns about the
rulemaking. Dr. Alisa Baer suggested NHTSA's efforts, and those of the
industry and/or the child passenger safety community, could be better
spent on correcting misuse or nonuse of child restraints.\69\ Dr. Baer
argued that Table 9 of the NPRM showed ``the injury rates for the under
1-year-olds (presumably the majority of whom are rear-facing) are
nearly 4 times lower than for the 1-3 year-olds (presumably the
majority of whom are forward-facing).'' She stated that the benefits
seem low and may not outweigh the costs of meeting the standard--costs,
she said, that include not only material costs (such as foam) but also
research and development and crash testing costs. The commenter said
the time and money spent on ensuring CRSs comply with the standard
could be better spent elsewhere, specifically, ``at decreasing the non-
use rate, especially amongst minority and low-income populations.''
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\69\ Dr. Baer stated, ``[C]urrent efforts to redesign seats to
optimize protection in side impacts are misguided. I believe the
primary focus should be on increasing the number of 1-3-year-olds
who ride rear-facing as the data suggest that keeping our
preschoolers rear-facing could have a much greater impact on
reducing fatalities & injuries in restrained children than the
proposed side impact standards will.''
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UMTRI and IIHS expressed concern with ``possible unintended
consequences of implementing this rulemaking.'' UMTRI suggested that
only forward-facing harnessed restraints be subject to the side impact
standard, ``since children in rear-facing child restraints are already
five times safer than those in [forward-facing] restraints in side
impacts,'' citing a 2007 study by Henary et al. to support its
view.\70\ IIHS echoed this view, also citing Henary.
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\70\ Henary, B., Sherwood, C.P., Crandall, J.R., Kent, R.W.,
Vaca, F.E., Arbogast, K.B., Bull, M.J. (2007) ``Car safety seats for
children: rear facing for best protection.'' Injury Prevention
13:398-402. (Note: as discussed below, this article was retracted in
2016.)
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The commenters above also expressed concern that adding larger,
padded side structures to meet the side impact standard may increase
the overall width of child restraints and result in children
prematurely moved from rear-facing restraints to forward-facing
restraints, from harnessed car seats to boosters, and from center
seating positions to outboard positions.
Agency Response
Increasing overall CRS use, tether use, and use of rear-facing
restraints by children above age 1 are very important goals, as each of
those measures can increase the number of child lives saved and
injuries avoided in crashes. NHTSA is actively involved in increasing
the use of CRSs and the correct use of restraint systems. These efforts
include developing and distributing training videos, producing public
safety announcements and various campaigns directed to caregivers of
children (in English and Spanish), leveraging all communication
resources (such as social media and the NHTSA website) to provide
information to parents and other caregivers, and expanding and
supporting the child passenger safety technician (CPST) curriculum used
to train and certify CRS fitting station technicians. In addition,
NHTSA's November 2, 2020 NPRM \71\ takes steps forward with proposed
changes to labeling requirements that are anticipated to result in more
children remaining rear-facing longer, and remaining in child safety
seats longer before transitioning to a booster.
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\71\ 85 FR 69388, supra.
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To be clear, however, this final rule focuses on improving the
protection provided by child restraints in side impacts and offers
expanded protection of children in a critically important crash mode--a
protection supplemental to the frontal crash protection the restraints
currently provide. Front and side crashes account for most child
occupant fatalities. MAP-21 requires NHTSA to issue a final rule to
amend FMVSS No. 213 to improve the protection of children seated in
child restraints in side impacts, but enhanced side impact protection
for children has been a priority for NHTSA before MAP-21.\72\ FMVSS No.
213a establishes a level of protection against unreasonable safety
risks in side impacts that every safety seat sold in this country will
have to provide and improves the protection afforded by the restraints
above that currently required by FMVSS No. 213. The efforts to improve
CRS use are complementary to and not inconsistent with improvements to
side crash safety, and will continue. Improved performance in side
crashes will not be achieved by improving CRS use alone, however.
Establishing FMVSS No. 213a improves the performance of child
restraints for the benefit of all children using the restraints.
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\72\ See NHTSA Vehicle Safety and Fuel Economy Rulemaking and
Research Priority Plan 2011-2013, March 2011, discussed in the
January 28, 2014 NPRM, supra, for this final rule (79 FR at 4572,
col. 3).
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NHTSA disagrees with the commenters that FMVSS No. 213a should not
apply to rear-facing child restraints. Dr. Baer may have misunderstood
Table 9 in the NPRM. Table 9 in the NPRM does not present injury rate
and instead presents average annual estimates of Abbreviated Injury
Scale (AIS) 2+ injuries.\73\ Since the population of children riding in
light vehicles is unknown, it is not possible to estimate injury rates.
The lower annual number of injuries to children
[[Page 39247]]
under 1 year of age could be related to fewer children of this age
group involved in crashes in comparison to 1- to 3-year-old children.
Applying FMVSS No. 213a to both front-facing and rear-facing child
restraints ensures all rear-facing child restraints will provide a
level of performance determined necessary to reduce an unreasonable
risk of death or injury in side impacts to restrained occupants.
---------------------------------------------------------------------------
\73\ AIS ranks individual injuries by body region on a scale of
1 to 6: 1 = minor, 2 = moderate, 3 = serious, 4 = severe, 5 =
critical, and 6 = maximum (untreatable).
---------------------------------------------------------------------------
UMTRI and IIHS argue that rear-facing CRSs are five times safer
than forward-facing CRSs, based on a 2007 study by Henary et al.\74\
NHTSA notes that the Henary study was called into question in 2016, and
after further analysis, the article was retracted by the journal Injury
Prevention, because the survey weights in the original analysis were
determined to be improperly handled. In 2017, a revised analysis of the
1988-2003 data, along with an extended analysis of the data through
2015, was published by a subset of the original authorship group.\75\
Their findings reveal that, although children 0 to 23 months still had
lower rates of injury while rear-facing compared with forward-facing,
the sample size was too small to achieve statistical significance.
---------------------------------------------------------------------------
\74\ Supra.
\75\ McMurry, T.L., Arbogast, K.B., Sherwood, C.P., Vaca, F.,
Bull, M., Crandall, J.R., Kent, R.W. ``Rear facing versus forward-
facing child restraints: an updated assessment,'' 2017, Injury
Prevention.
---------------------------------------------------------------------------
Regardless of the withdrawn Henary study, NHTSA does not find the
commenters' arguments persuasive. MAP-21 limits our discretion
regarding rear-facing child restraints, but even in the absence of the
statutory mandate, NHTSA finds a crucial need to apply FMVSS No. 213a
to rear-facing CRSs. Current guidance from the American Academy of
Pediatrics (AAP) and from NHTSA instruct parents that children should
ride rear-facing longer, and increasing numbers of child restraints are
designed to position children rear-facing longer. AAP recommends: ``All
infants and toddlers should ride in a rear-facing seat until they reach
the highest weight or height allowed by their car safety seat
manufacturer. Most convertible seats have limits that will allow
children to ride rear facing for 2 years or more.'' \76\ NHTSA
recommends for children 1- to 3-years-old: ``Keep your child rear-
facing as long as possible. It's the best way to keep him or her safe.
Your child should remain in a rear-facing car seat until he or she
reaches the top height or weight limit allowed by your car seat's
manufacturer.'' \77\ Because of these recommendations and the advances
in child seat designs, children are positioned rear-facing longer.\78\
As most child occupant fatalities occur in front and side crashes,
NHTSA believes it is critical that child restraints meet not only the
Federal standard for frontal protection (FMVSS No. 213), but also a
Federal standard for side impact protection (FMVSS No. 213a). Issuing
FMVSS No. 213a guarantees the safety seats are tested and certified to
a robust side impact standard when used rear-facing, and that children
are provided at least a minimum level of protection against
unreasonable risk of death or injury in side crashes.
---------------------------------------------------------------------------
\76\ https://www.healthychildren.org/English/safety-prevention/on-the-go/Pages/Car-Safety-Seats-Information-for-Families.aspx.
\77\ https://www.nhtsa.gov/equipment/car-seats-and-booster-seats.
\78\ Rear-facing car seat use among children 1- to 3-years-old
increased significantly from 9.4 percent in 2015 to 13.7 percent in
2017. Li, H.R., & Pickrell, T. (2018, September). The 2017 National
Survey of the Use of Booster Seats (Report No. DOT HS 812 617).
Washington, DC: National Highway Traffic Safety Administration.
---------------------------------------------------------------------------
b. Will child restraints become excessively large and heavy?
Dr. Baer, UMTRI and IIHS raised concerns that child restraints
would get wider because of meeting FMVSS No. 213a. Dr. Baer commented
that the side impact rule is ``virtually ensuring that car seats are
only going to get wider and bulkier at the head area.'' The commenter
believed that the increased bulk would result in parents not able to
fit car seats side-by-side in rear seats, and so the oldest child will
be ``put into a backless booster, as this is typically the narrowest,
and least expensive, restraint available.'' UMTRI expressed concern
that adding larger, padded side structures ``has potential to increase
the overall width of child restraints,'' which could result in children
moved from center seating positions to outboard positions. IIHS echoed
this concern, and stated ``even moderate increases in size may result
in fewer seats that fit in the rear seats of smaller vehicles.''
Conversely, ARCCA \79\ responded to the comments to the NPRM about
the potential increase in the size and weight of child restraints.
ARCCA shared information gained from car seats tested pursuant to a
side impact test found in European New Car Assessment Program (Euro-
NCAP) consumer education program. ARCCA stated that Euro-NCAP test
results are provided to the public to aid purchasers in the selection
of CRSs, and that as a result of these test programs, most suppliers of
European child seat manufacturers strive to score well in those tests.
---------------------------------------------------------------------------
\79\ Comment dated July 1, 2014. There were two comments from
ARCCA.
---------------------------------------------------------------------------
ARCCA believed that FMVSS No. 213a will have minimal effect on CRS
cost, weight, and width. The commenter supported its view with an
example of an infant-only CRS sold in Europe and the U.S. The
restraint's European version differs from the U.S. version by way of
side wings with a wing depth of 4\1/2\ inches, compared to the U.S.
version that has a wing depth of only 2\1/2\ inches. ARCCA stated that
when tested with a 12-month-old CRABI infant dummy in accordance with
the proposed ISO side impact test protocol,\80\ the U.S. version failed
to contain the head. The head hit the simulated intruding door,
resulting in HIC values ranging from 2,577 to 4,783. In contrast, the
commenter stated, the European version, with its deeper side wings,
contained the head and prevented contact with the simulated intruding
door, resulting in a HIC value of 827 (a 68 to 83 percent reduction in
the HIC value).
---------------------------------------------------------------------------
\80\ ARCCA did not provide details of the ISO test protocol.
ARCCA may be referring to the test details provided in the report,
ISO TR 14646:2007, ``Road vehicles--Side impact testing of child
restraint systems--Review of background data and test methods, and
conclusions from the ISO work as of November 2005.''
---------------------------------------------------------------------------
[[Page 39248]]
ARCCA stated that the U.S. and European versions of this infant
seat were manufactured using the same plastic shell. The side wings of
the European version were deepened simply by extending the expanded
polystyrene (EPS) lining beyond the plastic shell. While the wings were
deepened in the European version, the width of the infant seat was the
same as the U.S. version. ARCCA stated that the weight increase due to
the deepening of side wings was negligible (approximately one-eighth of
a pound (\1/8\ lb)) and the increased cost for the extended EPS was
minimal, less than one dollar. ARCCA believed the proposed rulemaking
will significantly improve child occupant crash protection in side
impacts and rollovers, and have minimal effect on CSS cost, weight, and
width.
Agency Response
Data indicate that child restraints will not become excessively
large or heavy due to FMVSS No. 213a, and rear-facing CRSs should not
be excluded from the side impact protection requirements based on a
concern about larger and wider CRS designs. As IIHS points out, only
one rear-facing seat failed to contain the 12-month-old CRABI's head in
NHTSA's test program described in the NPRM, which indicates that many
rear-facing seats may not need to be redesigned in any way to meet
FMVSS No. 213a.
Commenters Dr. Baer, UMTRI and IIHS speculated about bulkier child
restraints and the consequences that the bulkiness could cause, but
provided no data or other information supporting their views. In
contrast, ARCCA provided information showing that the width and weight
of an infant carrier sold in Europe (designed to provide side impact
protection) were almost identical to the U.S. version of the model.
ARCCA's information indicates side impact protection can be provided by
car seats without having to increase width or weight.
After reviewing the comments, NHTSA followed up with further
evaluation of whether manufacturers must widen forward-facing
restraints to meet the side impact protection requirements. The agency
evaluated two pairs of CRS models.\81\ For each pair, one of the child
restraints was advertised as providing more side impact protection than
its related twin. NHTSA measured the width of each CRS at the locations
where a child's head, abdomen and hips would be when restrained in the
CRS. NHTSA found that, for each CRS advertised as having enhanced side
impact protection features over its twin, each was wider in the upper
area of the CRS near the head position.
---------------------------------------------------------------------------
\81\ Louden, A., & Wietholter, K. (2022, March). FMVSS No. 213
side impact test evaluation and revision (Report No. DOT HS 812
791). Washington, DC: National Highway Traffic Safety Administration
(hereinafter Louden & Wietholter (2022)). Available in the docket of
this final rule.
---------------------------------------------------------------------------
NHTSA then conducted sled tests of the CRSs using the Q3s dummy
with the CRS in the forward-facing mode. For each CRS pair, the agency
observed that the HIC15 value measured by the Q3s dummy was greater for
the wider CRS (see Table 10). The HIC15 measurements of the Q3s were
greater for both the Britax Advocate and Graco Nautilus Safety
Surround, which are wider than their corresponding models, the Britax
Boulevard and Graco Nautilus 65, respectively. This testing
demonstrated that child restraints cannot simply be widened to meet the
FMVSS No. 213a side impact test; simply widening the restraint may, in
fact, degrade performance. Manufacturers will likely use different
engineering solutions (e.g., designing in energy-absorbing components)
to improve performance rather than just widen the restraint. A well-
engineered restraint could meet the requirements of this final rule
without becoming wider.
Concerns about rear-facing CRSs ``bulking-up'' to meet the side
impact protection requirements also appear unwarranted. As will be
discussed in a section below, test data from NHTSA's tests developing
this final rule indicate that not all side wings and padding protect
the same, and in some cases, ``more'' of a countermeasure (padding,
structure) was not necessarily ``better.'' Width, wings, padding,
padding-like features, and other countermeasures employed to provide
protection in side impacts must be engineered to attain the performance
specified by FMVSS No. 213a. Adding bulk and weight to a child
restraint is not necessary and can be counterproductive.
Table 10--Upper Width and HIC15 Values in Tests With the Q3s Dummy in Britax Boulevard and Britax Advocate CRS
Models in Forward-Facing Configuration
----------------------------------------------------------------------------------------------------------------
Advertised side
Database test No. CRS HIC15 protection Upper width
----------------------------------------------------------------------------------------------------------------
CRS Pair 1:
10105........................ Britax Boulevard... 522 2 Layers of Side Impact 460
Protection (energy-
absorbing shell and
foam-lined head rest).
10106........................ Britax Advocate.... 665 3 Layers of Side Impact 465
Protection (energy
absorbing shell, foam-
lined headrest and
external cushions).
CRS Pair 2:
10108........................ Graco Nautilus 65.. 609 EPS Energy Absorbing 455
Foam and Reinforced
Steel.
10109........................ Graco Nautilus 838 EPS Energy Absorbing 470
Safety Surround. Foam, Reinforced Steel
and Safety Surround
Technology (safety
surround means that the
head rest has a thicker
foam).
----------------------------------------------------------------------------------------------------------------
NHTSA also believes there is a technical incentive in FMVSS No.
213a that encourages designs toward narrower CRSs. Under this final
rule, the impact velocity between the door and the CRS will be lower
for narrow CRSs compared to wider CRSs. Narrower CRSs are at a greater
distance from the edge of the sliding seat and so the door will impact
the CRS at a later time after first impacting the sliding seat. This
later impact will result in a lower relative velocity of the sliding
seat with respect to the door at the time of impact with the CRS.
NHTSA studied this aspect of the test procedure in following up on
the commenters' concern about the widths of CRSs. NHTSA analyzed the
relative velocity at impact time between the door and the CRS for a
wide CRS (Safety 1st Advanced Air+, 520 mm maximum width) and narrow
CRS (Chicco Next Fit, 460 mm maximum width). As shown in Figure 1
below, the wider CRS is impacted by the door at a relative velocity of
29.19 km/h while the narrow one is impacted at 26.59 km/h. Both HIC15
and chest deflection were lower in the test of the narrow CRS (Chicco
[[Page 39249]]
Next Fit) than the wide CRS (Safety 1st Advance SE Air+). These CRSs
are designed differently, so their countermeasures could have affected
the HIC15 and chest deflection values measured by the dummy in the
tests. Yet these results suggest that the FMVSS No. 213 side impact
test will not in and of itself lead to wider CRSs.
In sum, based on NHTSA's testing of various types of CRSs in the
side impact test protocol, NHTSA believes that CRSs do not have to be
wider or bulkier to meet the side impact performance requirements. In
fact, our evaluations showed that some narrower CRSs performed better
than wider CRSs.
[GRAPHIC] [TIFF OMITTED] TR30JN22.004
c. More Bulk Is Not Necessarily Advantageous; the 2017 Test Program
In 2017, NHTSA tested child restraint systems on the side impact
seat assembly (SISA) as configured to the specifications of this final
rule. There were two parts to this program. The first part of the
testing was conducted to compare results of tests on the final SISA
configuration with test results from 2012 using the proposed SISA.
Three forward-facing CRS models (Evenflo Triumph,\82\ Evenflo Titan and
Evenflo Tribute) and three rear-facing CRS models (Evenflo Tribute,
Safety 1st Alpha Omega and Graco My Ride 65) were tested using the Q3s
dummy on the final SISA to compare to the results from corresponding
sled tests conducted on the proposed SISA. Paired comparison analyses
(see Table 11) show that HIC15 and chest deflection results on the
proposed and final SISA were not significantly different (p>0.05).
These data indicate that changes to the SISA between the NPRM and final
rule did not affect test results from tests of the CRSs.
---------------------------------------------------------------------------
\82\ The Evenflo Triumph was produced in 2009 which ensured this
model had not been modified to improve side impact in response to
the 2014 NPRM. The agency also tested a more recently produced model
which had very similar performance.
Table 11--Paired Comparison T-Test Results of Tests Conducted Using the Final SISA Configuration and the Proposed SISA
--------------------------------------------------------------------------------------------------------------------------------------------------------
Final rule SISA configuration NPRM SISA configuration
-------------------------------------------------------------------------------------------------------------------
Dummy, configuration and restraint Chest Chest
type Test No. CRS HIC15 deflection Test No. CRS HIC15 deflection
[mm] [mm]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Q3s in Forward Facing (FF) 10274 Evenflo Triumph (2009) 498.8 11.4 7561 Evenflo Triumph 463.8 14.6
Convertible Installed with CRAS. Advantage DLX.
8252 Evenflo Triumph 445.8 16.1
Advantage DLX.
8254 Evenflo Triumph 468.7 13.5
Advantage DLX.
10276 Evenflo Titan......... 1029.3 28.3 7557 Evenflo Titan......... 846.5 20.6
10101 Evenflo Tribute....... 760.0 20.9 7547 Evenflo Tribute....... 788.0 20.2
T.Test................ 0.192 0.897 ......... ...................... ......... ..........
Q3s in Rear Facing (RF) Convertible 10282 Evenflo Tribute....... 611.5 23.4 7554 Evenflo Tribute....... 763.0 22.4
Installed with lower anchors only
(LA only).
10283 Safety 1st Alpha Omega 396.4 26.0 7553 Safety 1st Alpha Omega 407.0 25.6
10284 Graco My Ride 65...... 778.3 22.3 8260 Graco My Ride 65...... 751.0 25.0
8264 Graco My Ride 65...... 681.0 31.0
T.Test................ 0.869 0.341 ......... ...................... ......... ..........
--------------------------------------------------------------------------------------------------------------------------------------------------------
The second part of the testing was to assess the performance of
more recently produced child restraint systems to the requirements of
then-pending FMVSS No. 213a. NHTSA conducted 18 tests of 17 CRS models
on the final SISA configuration. The 17 models represented 9 different
types of child restraints, including infant, convertible
[[Page 39250]]
and combination CRSs. NHTSA selected CRSs that had a variety of self-
described (advertised) side impact protection features.
The data from the 2017 test program indicated that child restraint
system designs had changed since the publication of the NPRM in 2014.
Of the 17 models tested, one (1) model had no side impact protection
advertised, seven (7) models advertised that the product was side
impact-tested or had side impact protection, and nine (9) models self-
described the side impact technology used. Among the selected CRSs were
2 pairs of CRS models where one of the CRS had ``incremental'' improved
side impact protection, based on their product description, compared to
the other CRS. The Graco Nautilus and the Graco Nautilus Safety
Surround (discussed above this preamble) were very similar models but
the latter had a thicker head rest structure that was advertised as
providing extra protection. The Britax Boulevard and Britax Advocate
(also discussed above) were also CRSs that appeared to be similar, but
the Britax Boulevard only had two levels of side impact protection
while the Advocate had three levels of protection (according to the
advertising).
NHTSA tested the child restraints with the Q3s 3-year-old child
dummy and the CRABI-12-month-old dummy. Forward-facing CRSs were
installed using the lower anchors of the child restraint anchorage
system required by FMVSS No. 225 and the tether anchorage, and rear-
facing CRSs were installed using the lower anchorages only. Tables 12
and 13 provide a test matrix of the CRS name, orientation, installation
method, dummy used and recorded injury measures.
Table 12--Test Matrix and Summary Results of Tests With the Q3s ATD Using the Final SISA Configuration
----------------------------------------------------------------------------------------------------------------
HIC15 [g] Chest
---------------- deflection
Database No. CRS Orientation Installation [mm]
IARV=570 ---------------
IARV=23
----------------------------------------------------------------------------------------------------------------
10100.................. Chicco NextFit.. FF Convertible.. CRAS............... 582.0 18.7
10101.................. Evenflo Tribute. FF Convertible.. CRAS............... 760.3 20.8
10102.................. Cosco Scenera FF Convertible.. CRAS............... 979.8 26.8
Next.
10103.................. Maxi-Cosi Pria FF Convertible.. CRAS............... 512.9 17.6
70.
10104.................. Evenflo Chase... FF Combination.. CRAS............... 937.5 24.3
10105.................. Britax Boulevard FF Convertible.. CRAS............... 521.7 * 7.08
10106.................. Britax Advocate. FF Combination.. CRAS............... 665.3 18.3
10107.................. Safety 1st FF Convertible.. CRAS............... 616.3 27.7
Advance SE Air+.
10108.................. Graco Nautilus FF Combination.. CRAS............... 609.0 13.6
65.
10109.................. Graco Nautilus FF Combination.. CRAS............... 838.5 17.9
Safety Surround.
10115.................. Cosco Scenera RF Convertible.. LA Only............ 677.7 26.2
Next.
10116.................. Graco Size4Me 65 RF Convertible.. LA Only............ 778.5 23.5
10118.................. Evenflo Triumph. RF Convertible.. LA Only............ 487.8 12.2
10117.................. Baby Trend RF Convertible.. LA Only............ 963.7 25.8
PROtect.
----------------------------------------------------------------------------------------------------------------
Note: CRAS means the full child restraint anchorage system, LA Only means lower anchorages of the child
restraint anchorage system, RF means rear-facing, and FF means forward-facing.
* Possible data anomaly.
Results shown in Table 12 show that among forward-facing CRSs
tested with the Q3s dummy, 20 percent (2/10) had HIC15 values less than
or equal to the IARV of 570, and 70 percent (7/10) had chest deflection
less than or equal to the IARV of 23 mm. Among rear-facing CRSs tested
with the Q3s dummy, 25 percent (\1/4\) had HIC15 values less than or
equal to the IARV of 570 and 25 percent (\1/4\) had chest deflection
values less than or equal to the IARV of 23 mm.
Table 13--Test Matrix and Summary Results of Tests With the CRABI 12-Month-Old ATD Using the Final SISA
Configuration
----------------------------------------------------------------------------------------------------------------
TRC test No. CRS Orientation Installation Contact
----------------------------------------------------------------------------------------------------------------
10110.................. Britax B-Safe 35 RF Infant.............. LA Only................ No.
10112.................. Cybex Aton 2 RF Infant.............. LA Only................ No.
using
telescopic side
arm.
10111.................. Evenflo Embrace RF Infant.............. LA Only................ No.
LX.
10114.................. Maxi-Cosi Mico RF Infant.............. LA Only................ No.
AP.
----------------------------------------------------------------------------------------------------------------
Note: LA Only means lower anchorages of the child restraint anchorage system and RF means rear-facing.
As shown in Table 13, rear-facing CRS (infant carriers) tested with
the 12-month-old CRABI dummy showed that 100 percent (4/4) met the
containment criteria.
General Observations
The 2017 test results \83\ with the Q3s dummy show fewer child
restraints able to conform to the performance requirements of FMVSS No.
213a, compared to test results from earlier tests. In the 2014 tests
reported in the NPRM, among 12 CRS models in the forward-facing mode
tested with the Q3s dummy, 41 percent (5/12) had HIC15 values passing
the IARV and 75 percent (9/12) had chest deflection passing the IARV.
Additionally, 40 percent (2/5) of rear-facing CRSs tested with the Q3s
dummy had HIC15 and
[[Page 39251]]
chest deflection values passing their respective IARVs. Among rear-
facing CRSs (infant carriers) tested with the 12-month-old CRABI dummy,
91 percent met the containment criteria in the tests.
---------------------------------------------------------------------------
\83\ Louden & Wietholter (2022). Available in the docket of this
final rule.
---------------------------------------------------------------------------
It should be noted that for the fleet tests presented in the NPRM,
NHTSA selected the CRS models to obtain a representation of the market
at the time, with a variety of CRS manufacturers and models. For the
2017 testing done with the final SISA configuration, NHTSA selected
CRSs that had a variety of side impact protection features, but the
CRSs were not necessarily a representation of the market. The goal of
the second part of the tests using the final SISA configuration
presented in Tables 12 and 13 was to learn how the CRSs with advertised
improved side impact protection performed in the side impact test.
To select the CRSs that would be tested for the final rule
evaluations, NHTSA examined CRS designs tested in 2011-2012 with
designs updated in 2016-2017. The comparisons of designs were only done
visually, i.e., NHTSA did not undertake tear-down analyses of the
underlying structure designs.
In the test, the agency observed that some of the designs that were
not updated, or that were minimally updated, such as the Graco Classic
Ride 50,\84\ Evenflo Tribute, and Evenflo Chase, maintained the same
performance as in 2012 (see Table 5). In contrast, the performance
measures (HIC15, chest deflection, head contact) in other models that
had been redesigned since the NPRM were markedly different than in
their respective older versions. For example, the redesigned Britax
Advocate had higher HIC15 measures, and the Safety 1st Advance SE Air+
and Cosco Scenera had higher chest deflections (see Table 14) than
their respective prior versions. The redesigned Britax Advocate has a
different shell, a side structure with different shape and more
coverage (but has a similar adjustable head restraint as the older
version). The redesigned and prior versions of the Safety 1st and Cosco
models had differences in the side structures of the CRS at the head
and chest areas, and the newer versions appeared to be thicker in the
head and torso/pelvis area. The Graco Nautilus 65 2017 showed improved
chest deflections compared to the Graco Nautilus 2012, while the Graco
Nautilus Safety Surround 2017 had increased HIC15 compared to the Graco
Nautilus 2012.
---------------------------------------------------------------------------
\84\ Also known as the Comfort Sport.
Table 14--Comparison of the Performance of Forward-Facing and Rear-Facing CRS Models in Tests With the Proposed and Final SISA Configurations
--------------------------------------------------------------------------------------------------------------------------------------------------------
Chest
Database No. SISA configuration CRS model HIC15 deflection Orientation
[mm]
--------------------------------------------------------------------------------------------------------------------------------------------------------
7544......................... NPRM......................... Evenflo Chase.............. 766 18.7 Forward Facing.
8253......................... NPRM......................... 987 20.1
8255......................... NPRM......................... 853 25.0
8257......................... NPRM......................... 784 25.4
10104........................ Final........................ 937 24.3
7547......................... NPRM......................... Evenflo Tribute............ 788 20.2 Forward Facing.
10101........................ Final........................ 760 20.9
8276......................... NPRM......................... Graco Classic Ride 50/Graco 742 19.3 Forward Facing.
Comfort Sport.
8278......................... NPRM......................... 679 21.5
8280......................... NPRM......................... 675 19.6
10020........................ Final........................ 672 21.6
10021........................ Final........................ 716 20.6
10022........................ Final........................ 691 20.1
7545......................... NPRM......................... Britax Advocate............ 365 19.5 Forward Facing.
10106........................ Final........................ 665 18.3
7546......................... NPRM......................... Safety 1st Air Protect/ 624 16.5 Forward Facing.
Advance SE Air+.
10107........................ Final........................ 616 27.7
8283......................... NPRM......................... Cosco Scenera/Scenera Next. 685 19.2 Rear Facing.
8285......................... NPRM......................... 714 20.2
8287......................... NPRM......................... 660 23.4
10115........................ Final........................ 678 26.2
8277......................... NPRM......................... Graco Nautilus/Nautilus 65/ 654 17.7 Forward Facing.
Nautilus Safety Surround.
8279......................... NPRM......................... 597 19.5
8281......................... NPRM......................... 625 17.0
10108........................ Final........................ 609 13.6
10109........................ Final........................ 839 17.9
7562......................... NPRM......................... Maxi Cosi Priori/Maxi Cosi 388 21.1 Forward Facing.
Pria 70.
10103........................ Final........................ 512 17.6
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: Bold = Increased Value, Italic = Decreased Value.
Based on this testing (Table 12 and Table 14) NHTSA believes that
some of the more recently tested CRS designs may have added unnecessary
bulk. Injury values are higher in some designs that had added mass
(thickness) \85\ than those without it. The 2017 testing indicates that
placement of coverage, materials, internal structures, shape of the
coverage and other factors must be purposefully engineered, as more is
not necessarily better.
---------------------------------------------------------------------------
\85\ Table 10 of this final rule measured the width of the CRSs
with and without additional padding and documented the description
of the different side impact protection designs. Some CRSs were
simply visually inspected where they may have appeared to have
thicker structures.
---------------------------------------------------------------------------
NHTSA had thought in the 2014 NPRM that CRSs with greater side
coverage performed better than CRSs with a less side coverage. Designs
meeting FMVSS No. 213a's performance requirements are feasible, but the
data
[[Page 39252]]
from the 2017 program show there are optimal ways to add structure and
padding, and ways that added bulk could have an adverse effect. The
test procedure adopted by this final rule will provide a means for CRS
developers to assess, in a meaningful way, the performance of their
designs and optimize the protection of children in side impacts.
d. The 40-lb Limit for Coverage of the Standard
Consistent with the Safety Act and NHTSA's guiding principles for
this rulemaking, NHTSA proposed to apply the side impact test
requirements to CRSs designed to seat children in a weight range from
birth to 18.1 kg (0 to 40 lb). The Safety Act requires each FMVSS to be
appropriate for the particular type of motor vehicle equipment for
which it is prescribed.\86\ NHTSA determined the side protection
standard would be appropriate for child restraints for children in the
0 to 18.1 kg (40 lb) group \87\ because these children have a high rate
of child restraint use (less than 1-year-old = 97.5 percent and 1- to
3-years-old \88\ = 94.3 percent according to the 2019 National Survey
of the Use of Booster Seats (NSUBS) \89\). Their high use rate provides
a good opportunity for reducing injuries and fatalities through a side
impact regulation.\90\
---------------------------------------------------------------------------
\86\ 49 U.S.C. 30111(b).
\87\ This group encompasses children ages birth to about 4
years.
\88\ Note that, in survey data, a child who is 1 day shy of his
or her 4th birthday is still considered a 3-year-old. Therefore,
survey data representing 1- to-3-year-old children include 3-year-
old children who are nearly 4-years-old. Also, the 40 lb weight
limit represents the weight of a 75th percentile 4-year-old child
and an average 5-year-old child.
\89\ Enriquez, J. (2021, May). The 2019 National Survey of the
Use of Booster Seats (Report No. DOT HS 813 033). National Highway
Traffic Safety Administration. NSUBS is a probability-based
nationwide child restraint use survey conducted by NHTSA's National
Center for Statistics and Analysis (NCSA).
\90\ Children between 4- and 12-years-old have lower child
restraint use (4- to 7-year-olds = 55 percent and 8- to 12-year-olds
= 6 percent). Data show that 43 percent of 4- to 7-year-old and 78
percent of 8- to 12-year-old children use seat belts.
---------------------------------------------------------------------------
NHTSA also determined that focusing on the 0 to 18.1 kg (40 lb) (0-
to 4-years-old) age group is appropriate because countermeasures are
practicable for this age group. Real-world data show that head injuries
are the most common injuries in a side impact for 0- to 4-year-old
children. According to McCray,\91\ head injuries in children 1- to 3-
years-old are slightly higher than overall for children 0 to 12 year of
age. Using padding and/or larger side wings to keep the child's head
contained and protected enables forward- and rear-facing CRSs to meet
the requirements of this final rule without adding any additional
structures to the safety seats. The Q3s dummy is also representative of
children in the upper range of this age group and can be used to assess
the performance of child safety seat countermeasures in protecting
against unreasonable head impact.
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\91\ McCray, L., Scarboro, M., Brewer, J. ``Injuries to children
one to three years old in side impact crashes,'' 20th International
Conference on the Enhanced Safety of Vehicles, 2007. Paper Number
07-0186.
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NHTSA also explained in the NPRM that the FMVSS No. 213a side
impact test replicates a near-side crash as experienced by a child
under 18.1 kg (40 lb) in a safety seat. The agency's test results
indicate that an important factor in the near-side impact environment
is the position of the child's head with respect to the ``beltline''
(also referred to as the windowsill) \92\ of the vehicle door. When the
child's head is below the beltline--as likely with children weighing up
to 18.1 kg (40 lb) (0- to 4-year-old) in child restraints--protection
of the child is critically dependent on the child safety seat, as
negligible benefit is expected to be attained from the vehicle's side
curtain air bags. Older children restrained in CRSs typically sit high
enough so that the child's head is above the beltline and within the
area covered by the side curtain air bag.
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\92\ The beltline of a vehicle is a term used in vehicle design
and styling, referring to the nominally horizontal line below the
side glazing of a vehicle, which separates the glazing area from the
lower body. Passenger vehicles are required to provide head
protection in side impacts and ejection mitigation in rollovers,
pursuant to FMVSS No. 214 and FMVSS No. 226, ``Ejection
mitigation,'' respectively. The countermeasure provided to meet
FMVSS No. 226 in passenger vehicles, a side curtain air bag, must
meet performance requirements that, in effect, will necessitate
coverage of the side windows to the beltline of the vehicle.
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Finally, NHTSA emphasized that, due to the absence of an array of
side impact child test dummies, focusing this rulemaking on CRSs
designed for children in a weight range that includes weights up to
18.1 kg (40 lb) properly accords with 49 U.S.C. 30111(b)'s provision
that each FMVSS be appropriate for the types of motor vehicle equipment
for which it is prescribed. NHTSA determined that the Q3s dummy
(weighing 14.5 kg (32 lb)) is representative of young children weighing
under 18.1 kg (40 lb) and is appropriate as a test device for CRSs
recommended for children weighing up to 18.1 kg (40 lb). The dummy
would not be a suitable dummy to test the performance of CRSs in
protecting children weighing more than 18.1 kg (40 lb), as it is not
representative of children for whom the CRS is sold.
Comments Received
NHTSA received diverse comments on the 40-lb applicability
threshold. Commenters generally agreed that the absence of a dummy
larger than the Q3s limited the agency's applying the side impact
standard to child restraints for children weighing more than 18.1 kg
(40 lb), but several commenters urged NHTSA to develop new test dummies
or use existing ones, such as frontal test dummies. No commenter
objected to NHTSA's requiring manufacturers of booster seats to limit
use of boosters to children weighing at least 18.1 kg (40 lb); six
commenters expressly supported the provision (IIHS, Dorel, Britax,
JPMA, UMTRI and Safekids). Advocates requested NHTSA provide more
support for its determination that children weighing more than 18.1 kg
(40 lb) may benefit from side curtain air bags.
IIHS concurred with NHTSA's proposed threshold applying FMVSS No.
213a to CRSs for children weighing less than 18.1 kg (40 lb) for the
reasons given in the NPRM. IIHS provided data to support the view that
children weighing more than 18.1 kg (40 lb) in booster seats are seated
high enough to take advantage of the vehicle's side curtain air bags.
The commenter explained that data it obtained during its tests of
booster seat belt fit indicate that the center of gravity (CG) of a
typical 6-year-old child's head is 600-650 millimeters (mm) above the
vehicle seat when seated in a booster, which is above the windowsill
(beltline) of 500 mm discussed in the NPRM.\93\ IIHS found that on
average, the seated height of the 6-year-old dummy in a booster seat is
within a few centimeters of the seated height of the 5th percentile
adult female dummy used in the rear seat of IIHS's dynamic side impact
test. IIHS stated that in the most recent five years of side impact
evaluations, more than 80 percent of more than 200 vehicle makes and
models received the top ratings for injury mitigation for the rear seat
occupant, and that the proportion jumps to 95 percent for the most
recent two years of evaluations. IIHS explained that in these tests,
injury risk to rear-seat occupants is reduced by a combination of
vehicle countermeasures such as curtain air bags, door structural
improvements, and voluntary padding of the beltline. IIHS stated it
expects ``vehicle countermeasures that have improved outcomes for the
5th percentile female dummy in our testing
[[Page 39253]]
would also reduce the likelihood of injury to a 6-year-old seated in a
booster seat.''
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\93\ NHTSA proposed a 500 mm (19.6 in) beltline height for the
SISA. See, 79 FR at 4587-4588.
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Agency Response
After considering the comments and other available information,
NHTSA has adopted the proposed application of FMVSS No. 213a for the
reasons explained in the NPRM and further discussed below. Standard No.
213a will apply to add-on child restraint systems that are recommended
for use by children in a weight range that includes weights up to 18.1
kg (40 lb).\94\
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\94\ Harnesses and car beds are excepted from the standard.
---------------------------------------------------------------------------
Several commenters suggested NHTSA adopt other test dummies to
expand the applicability of FMVSS No. 213a to CRSs for children
weighing more than 18.1 kg (40 lb). Safe Kids, Consumers Union (CU) and
Advocates urged NHTSA to develop a 6-year-old and/or 10-year-old child
side impact dummy. Safe Ride News (SRN) encouraged the agency to work
swiftly to adopt the Q6 dummy for use specifically in side impact
tests. Transport Research Laboratory (TRL) supported using the
omnidirectional Q-Series dummies used for side impact testing in United
Nations Economic Commission for Europe Regulation 129 (ECE R.129).\95\
TRL stated that the dummies were capable of distinguishing differences
in the design of child restraints, and that a Q6s (6-year-old child
dummy) has been developed, along with a side impact kit for the Q10
(10-year-old child dummy). ARCCA suggested NHTSA use the Hybrid III
(HIII) frontal impact 6-year-old dummy, and measure only head
containment and structural integrity. In contrast, Graco cautioned that
the use of larger test ATDs should be considered when they have been
confirmed to withstand side impact crash forces and have proven
biofidelity in the direction of a side collision.
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\95\ ECE R.129, ``Uniform provisions concerning the approval of
enhanced child restraint systems used on board vehicles (ECRS),''
http://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2013/R129e.pdf.
---------------------------------------------------------------------------
NHTSA has decided against expanding the applicability of FMVSS No.
213a to child restraints recommended for children weighing more than
18.1 kg (40 lb). TRL suggested NHTSA consider the Q-series dummies
because they are currently used to test CRSs in United Nations Economic
Commission for Europe Regulation 129 (ECE R.129).\96\ NHTSA disagrees
with TRL. In 1999, First Technology Safety Systems (FTSS) \97\ deemed
the Q3 dummy's performance suboptimal in frontal testing, and even more
so in lateral. FTSS developed the Q3s dummy in response to the Q3's
suboptimal lateral performance. NHTSA has not evaluated the lateral
performance of the Q series 1-, 6- and 10-year-old dummies or Q series
side impact kits, but understands them to have the same shortcomings as
the original Q3. Given the unsatisfactory fundamental design of the Q
dummies, NHTSA decided not to use limited agency resources furthering
development of the Q-series 6- and 10-year-old dummies.\98\
---------------------------------------------------------------------------
\96\ ECE R.129, ``Uniform provisions concerning the approval of
enhanced child restraint systems used on board vehicles (ECRS),''
http://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2013/R129e.pdf.
\97\ In 2010, FTSS merged to become Humanetics Innovative
Solutions.
\98\ NHTSA is developing the ``Large Omnidirectional Child
(LODC)'' 10-year-old child dummy, which is designed to have
biofidelic performance in lateral and frontal impact. Most of the
development work has been focused on frontal and oblique impacts.
NHTSA plans to evaluate and enhance the dummy for side impact
testing as well.
---------------------------------------------------------------------------
ARCCA suggested that NHTSA use the HIII frontal 6-year-old dummy to
evaluate CRS structural integrity and head containment. The commenter
argued that NHTSA could use the HIII 6-year-old dummy since it will use
the 12-month-old frontal CRABI dummy in FMVSS No. 213a's side impact
test.
NHTSA disagrees. As the agency explained in the NPRM, NHTSA decided
to use the frontal CRABI dummy because it would be fully restrained by
the child restraint on the SISA and no injury assessment reference
values would be taken. That is, the test with the fully restrained
frontal 12-month-old CRABI represents a best-case scenario for passing.
If a child restraint allowed the CRABI's head to contact the door under
these best-case circumstances, that would be a clear demonstration,
simply through observation of crash dynamics, that a child's head would
contact the door when involved in a real-world crash. Thus, while the
12-month-old CRABI dummy is not a side impact dummy, it could be
applied in a useful manner to evaluate aspects of CRS performance in
side impact. A failure to contain the 12-month-old CRABI's head would
lead to improved side impact designs (e.g., deeper side structure/wings
or shape changes in CRS adjustable head restraints).
The same cannot be said about the frontal 6-year-old test dummy.
Children younger than 1-year of age have the highest use of CRSs with
internal harnesses (nearly 100 percent per National Child Restraint Use
Special Study (NCRUSS) \99\), so fully restraining the 1-year-old CRABI
in the test replicates how children will be restrained in the real
world. In contrast, only 8 percent of children 6 years of age are
restrained in CRSs with internal harnesses. If the HIII 6-year-old
child dummy were restrained as 6-year-old children are usually
restrained in the real world, it would be restrained in a booster with
only a lap and shoulder belt. Many current booster seats could fail a
head containment criterion when tested with a frontal 6-year-old dummy,
even if the head of the 6-year-old dummy were above the beltline and
therefore likely to interact with a side curtain air bag in an actual
vehicle. To accurately simulate the side impact crash environment in
such testing, a representation of the side air bag appears appropriate.
This rulemaking has not considered the implications of including a side
curtain air bag on the SISA and doing so is beyond the scope of this
final rule.
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\99\ NCRUSS https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/812142.
---------------------------------------------------------------------------
ARCCA believed that applying FMVSS No. 213a to child restraints for
children weighing up to 29.5 kg (65 lb) would better protect children
seated in far-side and center seating positions by preventing impact
with other occupants and CRSs adjacent to the child, and helping assure
they remain properly positioned in their restraint system. SRN believed
it is likely that shorter children do not gain the full protection of
side curtain air bags in the 18.1 to 29.5 kg (40 to 65 lb) weight
range. Neither commenter provided data to support their views.
Advocates and others argued that MAP-21 does not limit improvements
only to the use of CRS by children who weigh less than 18.1 kg (40 lb).
NHTSA has determined that, while the language of section 31501(a) of
MAP-21 is broad enough to encompass a large universe of child restraint
systems, there are practical and technical reasons for applying the
dynamic side impact test only to CRSs designed to seat children in a
weight range that includes weights up to 18 kg (40 lb). First, the
seated height of children weighing more than 18 kg (40 lb) who are
restrained in child restraints is typically sufficient to take
advantage of the vehicle's side impact protection systems, such as side
curtain air bags. Thus, the safety need for Standard No. 213's dynamic
side impact requirements is attenuated for these CRSs. NHTSA has also
determined that the test procedure of FMVSS No. 213a may not be
appropriate for testing child restraints recommended for children
[[Page 39254]]
weighing more than 18.1 kg (40 lb). A 6-year-old in a child restraint
will interact with vehicle side structures differently than a 3-year-
old, particularly around the vehicle beltline and with respect to a
side curtain air bag. The side impact seating assembly used in FMVSS
No. 213a does not include a side curtain air bag. The agency is unable
to conclude the side impact test reasonably replicates a near-side
crash as would be experienced by a child weighing over 18.1 kg (40 lb)
in the real world, since the side curtain air bag, a key vehicle
countermeasure affecting injury outcome to occupants whose heads are
above the beltline, is not represented in the test.
Second, there is no side impact dummy representative of children
larger than those represented by the Q3s that can reasonably be used to
test CRSs for children above 18 kg (40 lb) to the dynamic side impact
requirements in this final rule. As explained throughout this
rulemaking,\100\ without an appropriate test dummy, the data from a
dynamic test would not provide a meaningful assessment of the
performance of the CRS in protecting children of weights above 18.1 kg
(40 lb). For FMVSS No. 213's front-impact tests, NHTSA increased the
applicability of the standard to increasingly higher weight limits
gradually, and only when appropriate test dummies became available for
use in compliance testing, to ensure test data were meaningful and to
avoid giving a false sense of security about CRS performance. NHTSA is
developing the Large Omni-Directional Child ATD representative of a
seated 9- to 11-year-old child.\101\ When the development and
standardization process of this child dummy is complete, NHTSA will
consider a side impact test environment appropriate for evaluating CRSs
intended for use by older and larger sized children than those subject
to this final rule.
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\100\ See NPRM. 79 FR at 4572-4573.
\101\ Suntay, B., Carlson, M., Stammen, J., ``Evaluation of the
Large Omni-Directional Child Anthropomorphic Test Device,'' DOT HS
812 755, July 2019. Evaluation of the Large Omni-Directional Child
Anthropomorphic Test Device (bts.gov).
---------------------------------------------------------------------------
MAP-21 requires a final rule amending FMVSS No. 213, which means
that the rulemaking must be conducted in accordance with the Safety
Act. Under the Safety Act, NHTSA is authorized to prescribe Federal
motor vehicle safety standards that are practicable, meet the need for
motor vehicle safety, and are stated in objective terms.\102\ ``Motor
vehicle safety'' is defined in the Safety Act as ``the performance of a
motor vehicle or motor vehicle equipment in a way that protects the
public against unreasonable risk of accidents occurring because of the
design, construction, or performance of a motor vehicle, and against
unreasonable risk of death or injury in an accident, and includes
nonoperational safety of a motor vehicle.'' \103\ When prescribing such
standards, NHTSA must consider all relevant, available motor vehicle
safety information, and consider whether a standard is reasonable,
practicable, and appropriate for the particular type of motor vehicle
or motor vehicle equipment for which it is prescribed.\104\ NHTSA must
also consider the extent to which the standard will further the
statutory purpose of reducing traffic accidents and associated
deaths.\105\
---------------------------------------------------------------------------
\102\ 49 U.S.C. 30111(a).
\103\ 49 U.S.C. 30102(a)(8).
\104\ 49 U.S.C. 30111(b).
\105\ Id.
---------------------------------------------------------------------------
NHTSA has developed a standard that will improve the protection of
children seated in child restraint systems during side impacts, in
accordance with MAP-21, while meeting the criteria of Section 30111 of
the Safety Act. For the reasons explained above, the agency believes
that FMVSS No. 213a meets the need for safety, is stated in objective
terms, and is reasonable, practicable, and appropriate.
e. Improving Side Impact Protection for Children Older Than 3-Years-Old
To be clear, this final rule applying to child restraints for
children weighing up to 18.1 kg (40 lb) will significantly improve side
impact protection of most children up to age 6. According to the CDC
growth charts, about 100 percent of 3-year-old children, 75 percent of
4-year-old children, 50 percent of 5-year-old children, and 25 percent
of 6-year-old children weigh 18.1 kg (40 lb) or less.\106\ Child
restraints subject to this final rule can be used by all children 0- to
3-years of age, most 4-year-olds, half of 5-year-olds, and 25 percent
of 6-year-old children. This final rule improves the side impact
protection of all these children.
---------------------------------------------------------------------------
\106\ Center for Disease Control (CDC) 2000 Growth Charts.
https://www.cdc.gov/growthcharts/cdc_charts.htm. Last Accessed
August 8, 2018.
---------------------------------------------------------------------------
This final rule not only improves the side impact protection
offered by the safety seats but also increases the likelihood
caregivers will keep the children in the safety seats longer before
prematurely transitioning to a booster seat, which is an outcome that
improves child safety.\107\ Booster seats typically do not have
substantial side structure ``wings'' or an internal belt system to
restrain the child occupant, so it would be a technical challenge for
booster seats to meet the side impact requirements of this final rule.
However, because FMVSS No. 213a is written to apply specifically to
child restraints for children weighing less than 18.1 kg (40 lb),
manufacturers of booster seats will likely respond to this final rule
by marketing the seats as only suitable for children weighing more than
18.1 kg (40 lb) (so as to exclude the seats from meeting FMVSS No.
213a). NHTSA believes such a change that limits use of booster seats by
small children would benefit safety, as field data show that children
weighing less than 18.1 kg (40 lb) are safer in child safety seats than
in boosters.\108\ Thus, the 18.1 kg (40 lb) threshold will benefit
child passenger safety, as it will help keep children too small for
booster seats in child safety seats until they are ready for a booster
seat.
---------------------------------------------------------------------------
\107\ NHTSA recommends that children riding forward-facing
should be restrained in CRSs with internal harnesses (child safety
seats) as long as possible before transitioning to a booster seat.
https://www.nhtsa.gov/equipment/car-seats-and-booster-seats#age-size-rec.
\108\ NHTSA's November 2, 2020, NPRM, supra, also proposed that
booster seats must not be labeled for children weighing less than
18.1 kg (40 lb). 85 FR at 69427, col. 3. FMVSS No. 213 currently
permits booster seats only to be recommended for children weighing
at least 13.6 kg (30 lb) (S5.5.2(f)). Based on an analysis of field
data and other considerations, NHTSA proposed raising the 13.6 kg
(30 lb) value. We are concerned that 30 pounds corresponds to the
weight of a 50th percentile 3-year-old, and to the weight of a 95th
percentile 18-month-old; i.e., children too small to be safely
protected in a booster seat. In the November 2, 2020 NPRM, we
proposed to amend S5.5.2(f) to raise the 13.6 kg (30 lb) limit to
18.2 kg (40 lb), which is greater than the weight of a 97th
percentile 3-year-old (17.7 kg (39.3 lb)) and approximately the
weight of an 85th percentile 4-year-old.
---------------------------------------------------------------------------
Further, this final rule will also benefit the side protection of
children weighing more than 18.1 kg (40 lb) in several ways. A review
of CRS models in the market suggests that most child restraints sold
for children weighing less than 18.1 kg (40 lb) are designed to also be
used by children weighing more than 18.1 kg (40 lb) as forward-facing
CRSs with harnesses and as booster seats.\109\ As the seated height
difference between a 3-year-old and a 6-year-old is only 3.5 inches,
the countermeasures used by the combination seat to protect children
weighing less than 18.1 kg (40 lb) could also benefit the older child
in the booster seat mode.\110\ The restraints
[[Page 39255]]
will have the same frame and can use the adjustable head protection and
side padding countermeasures provided to meet this final rule to
protect children weighing more than 18.1 kg (40 lb).
---------------------------------------------------------------------------
\109\ These child restraints are commonly called ``combination
seats.'' They are sold for use with younger children (with a
harness) and older children (as a booster seat)
\110\ This observation accords with NTSB's comment that ``the
proposed tests encompass the majority of CRSs because the upper use
limit for most small restraint systems extends to at least 40 pounds
and the lower use limit is at or below 40 pounds . . .'' ``We
recognize that children at weights less than or greater than 40
pounds benefit from the increased protection provided by a harnessed
CRS.''
---------------------------------------------------------------------------
This final rule will also improve the side impact protection of
booster seats by better assuring that only children large enough (over
18.1 kg (40 lb)) to be protected by the side curtain air bag will use
the seats. NHTSA stated in the preamble to the NPRM that the height of
children weighing more than 18.1 kg (40 lb) seated in a CRS would be
sufficient to take advantage of the vehicle's side impact protection
systems, such as side curtain air bags.\111\ IIHS provided data
confirming that side curtain air bags can protect children weighing
over 18.1 kg (40 lb) seated in booster seats. The data show that the CG
of the head of a 6-year-old child seated in a booster seat is above the
beltline at 600-650 mm above the vehicle seat, and is within a few
centimeters of the position of the head of the 5th percentile adult
female test dummy. In IIHS's tests, the vehicles received the top
ratings for injury mitigation for the rear seat occupant represented by
the 5th percentile adult female test dummy, demonstrating the side
curtain air bags, door structural improvements, and padding of the
beltline were effective in protecting the 5th percentile adult female
in side impacts. IIHS's data indicate a 6-year-old in a booster is
situated in the rear seat similarly to a 5th percentile female, and
that both occupants will be positioned relative to the beltline and the
side curtain air bags in a manner that would enable them to benefit
from the vehicle countermeasures.
---------------------------------------------------------------------------
\111\ 79 FR at 4573, col. 2.
---------------------------------------------------------------------------
NHTSA has also reviewed more recent data IIHS presented at the 2018
Society of Automotive Engineers (SAE) Government Industry Meeting.\112\
The study showed that the HIII-6-year-old head CG in a high back
booster and a backless booster are above the beltline and are 33 and 64
mm lower, respectively, than that of the SID-IIs 5th percentile female
side impact dummy. These data again verify that a 6-year-old child in a
booster will be in-position to be protected by the vehicle's side
impact protection countermeasures, which include the side curtain air
bag and door structural improvements.
---------------------------------------------------------------------------
\112\ The IIHS SAE Government Industry meeting presentation
titled ``Booster seat characteristics in the US market'' can be
found in the docket.
---------------------------------------------------------------------------
Following on these findings, NHTSA measured the HIII 6-year-old
dummy in four booster seat models installed on the SISA and compared
its positioning with the SID-IIs dummy seated directly on the SISA. The
booster seats were the Evenflo Chase and the Graco Nautilus (high back
boosters), and the Harmony Youth and the Graco Affix (backless
boosters). The measurements show that the HIII 6-year-old dummy's head
CG, when seated in the highest booster seat (Graco Nautilus 65) is 1 mm
higher than that of the SID-IIs dummy seated on the SISA, and less than
5 cm (47.5 mm) lower than the SID-IIs dummy's head when seated in the
shortest booster seat (Graco Affix). All head CGs were above the
beltline (see Figure 2).
[GRAPHIC] [TIFF OMITTED] TR30JN22.005
These data confirm the similarity between the head position of the
6-year-old dummy seated in a booster seat and that of the 5th
percentile female dummy. FMVSS No. 226 ejection mitigation phase-in
requirements were completed in September 2017. Thus, not only will all
new vehicles have side curtain air bag technologies that will protect
these older children in booster seats, but most of the fleet will
incorporate these technologies by the
[[Page 39256]]
compliance date of this final rule. The technologies can benefit older
and larger children weighing more than 18.1 kg (40 lb) or with a
stature of more than 1100 mm (43.3 inches) when the children are
properly positioned by a typical booster seat.
The safety of booster seats will be directly improved by assuring
that only children large enough to be protected by the side curtain air
bag will use the seats. Until this final rule, booster seats could be
labeled for children with weights as low as 13.6 kg (30 lb).
Restricting booster seat use instructions to children weighing more
than 18.1 kg (40 lb) will help ensure they will be used only by
children large enough to take advantage of a vehicle's side protection
countermeasures. Booster seats have been shown to be highly beneficial
in frontal crashes, and are needed to transition children from safety
seats to a vehicle belt system. This final rule increases the safety of
booster seats by enhancing their utility in side impacts, in
furtherance of MAP-21's mandate to improve the protection of children
seated in child restraint systems during side impacts.
Since the NPRM's publication in 2014, NHTSA has seen a few booster-
seat models that provide a lower than typical boosting height (the
height that a booster seat raises a seated child), which may not raise
the height of children weighing more than 18.1 kg (40 lb) sufficiently
to take advantage of the vehicle countermeasures. Subsequently, NHTSA
sponsored a research program \113\ as a first step toward determining a
minimum boosting height for CRSs recommended for children weighing more
than 18.1 kg (40 lb) to ensure that these children can benefit from the
vehicle countermeasures and that the CRSs provide enough lift to
position the child properly relative to the vehicle's lap and shoulder
belts. More on this research is discussed at a later section of this
final rule.
---------------------------------------------------------------------------
\113\ Klinich, Kathleen D., Jones, Monica H., Manary, Miriam A.,
Ebert, Sheila H., Boyle, Kyle J., Malik, Laura, Orton, Nichole R.,
Reed, Matthew P., (2020, April). Investigation of potential design
and performance criteria for booster seats through volunteer and
dynamic testing (Report No. DOT HS 812 919). Washington, DC:
National Highway Traffic Safety Administration. Link: https://rosap.ntl.bts.gov/view/dot/49119.
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f. Weight as a Limiting Factor
Advocates stated ``a discussion of why weight alone is being
proposed as a limitation should be provided, considering the repeated
discussion of the obesity problem facing the nation's youth and the
agency's acknowledgement that seated height, rather than weight alone,
is the determining factor.''
Agency Response
The applicability of the standard is not only based on the child
weight recommendation for use of the CRS but also on the child height
recommendation. The NPRM proposed in S3 to apply the standard to ``add-
on child restraint systems, except for harnesses and car beds, that are
recommended for use by children in a weight range that includes weights
up to 18.1 kg (40 lb), or by children in a height range that includes
children whose height is not greater than 1100 mm.'' \114\ This final
rule adopts the proposed S3. Additionally, the dummy selection for side
impact dynamic testing is made taking into consideration weight and
height. Any CRS that is recommended for children weighing between 13.6
kg (30 lb) (corresponding to a 95th percentile 18-month-old) and 18.1
kg (40 lb) (corresponding to a 85th percentile 4-year-old) or a height
between 870 mm (34.3 inches) (corresponding to a 95th percentile 18-
month-old) and 1100 mm (43.3 inches) (corresponding to a 97th
percentile 4-year-old) will be tested with the Q3s dummy (see Table
15).
---------------------------------------------------------------------------
\114\ 79 FR at 4601.
Table 15--Comparison of Weight and Height by Percentiles for Young Children and Child ATDs 115
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Weight kg (lb) Height mm (in)
Percentiles ---------------------------------------------------------------------------------------------------------------------------------
3rd 5th 50th 95th 97th 3rd 5th 50th 95th 97th
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
12 MO Child................................................... 8.1 (18.1) 8.3 (18.5) 9.9 (22) 11.9 (26.4) 12.2 (27.2) 697.1 703.2 750.6 (29.6) 800.2 (31.5) 807.5 (31.8)
(27.4) (27.7)
12 MO CRABI................................................... .......... .......... 9.9 ........... ........... ........... ........... 740.4 ............ ............
(22.05) (29.15)
18 MO Child................................................... 9.3 (20.7) 9.5 (21.2) 11.3 13.5 (30.1) 14 (31) 753.6 761.1 (30) 814.4 (32.1) 868.2 (34.2) 875.9 (34.5)
(25.2) (29.7)
18 MO CRABI................................................... .......... .......... 11.1 ........... ........... ........... ........... 817.9 (32.2) ............ ............
(24.7)
24 MO Child................................................... 10.1 10.4 (23) 12.3 14.8 (32.9) 15.3 (33.9) 800.5 809 (31.9) 866.9 (34.1) 924.8 (36.4) 933.8 (36.8)
(22.5) (27.4) (31.5)
36 MO Child................................................... 11.4 11.9 13.9 (31) 17.2 (38.1) 17.7 (39.3) 875.9 884.9 947.4 (37.3) 1013.8 1023.7
(25.4) (26.4) (34.5) (34.8) (39.9) (40.3)
Q3s........................................................... .......... .......... 14.5 (32) ........... ........... ........... ........... 978 (38.5) ............ ............
48 MO Child................................................... 12.9 13.2 16 (35.5) 20.2 (44.8) 46.6 (46.6) 936.5 946.4 1015.8 (40) 1087.7 1098.2
(28.7) (29.4) (36.9) (37.3) (42.8) (43.2)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
The commenter's reference to ``the obesity problem facing the
nation's youth'' was not clear, but it could be that Advocates was
arguing that the standard should apply to child restraints for children
weighing more than 18.1 kg (40 lb). NHTSA disagrees with increasing the
40-lb threshold because the absence of a test dummy to test the side
impact protection provided to heavier children makes raising the
threshold non-evidence based and could provide a false sense of
security about the protection afforded to the larger children. This
issue is discussed at length in the section discussing the scope of the
new standard.
---------------------------------------------------------------------------
\115\ Center for Disease Control (CDC) 2000 Growth Charts.
https://www.cdc.gov/growthcharts/cdc_charts.htm... Last Accessed
August 8, 2018.
---------------------------------------------------------------------------
g. Labeling CRSs for Children Weighing Over 18.1 kg (40 lb)
1. Label as ``Not Tested in Side Impacts''
Comments Received
Advocates commented that booster seats designed for children
weighing more than 18.1 kg (40 lb) should be labeled to provide parents
with a warning that their child may not be protected in a side crash.
Advocates stated that the warning should indicate ``this CRS has not
been tested in side impacts for the protection of children weighing
more than 18.1 kg (40 lb).'' Similarly, a law student group suggested
there should be labeling or consumer information on the packaging of
CRSs informing consumers that the CRS has not been tested for side
impact crashes for children weighing more than 18.1 kg (40 lb).
Agency Response
NHTSA has carefully considered the request but declines to adopt
such a requirement in this final rule. The issue was not discussed in
the NPRM, and NHTSA would like the benefit of more public discourse on
the ramifications of such a requirement. NHTSA highly values consumers'
knowing how child restraints can protect their children's safety.
However, information provided
[[Page 39257]]
on or with child restraints must be carefully worded so as not to
confuse caregivers or cause unintended responses to it. For example,
the agency is concerned that a statement such as, ``This CRS has not
been tested in side impacts for the protection of children weighing
more than 18.1 kg (40 lb)'' may be interpreted by some as saying the
CRS is not regulated in any way under any Federal standard, since an
average consumer is unlikely to know the applicability or extent of
FMVSS No. 213 versus FMVSS No. 213a. Before adopting such a labeling
requirement, NHTSA should evaluate the risk that a caregiver might
respond to the label by deciding to forgo use of a booster seat or
other CRS entirely when the child reaches 18.1 kg (40 lb). Such an
outcome would lead to a degradation of child passenger safety. NHTSA is
also concerned that the statement might dampen efforts on the part of
researchers and engineers to develop potential improvements to side
impact protection for older children, such as by developing data-driven
countermeasures using methods (e.g., mathematical models along with
human body models) that simulate the side impact test of this final
rule.
2. Head Under Window Sill
Advocates suggested that instructions to parents (either in vehicle
manuals or other sources) should indicate that children below a certain
height, or whose head does not reach entirely above the sill of the
vehicle window, should be restrained properly in a safety seat since
they may not be afforded protection by side impact safety requirements
designed to protect adults. The commenter suggested that a similar form
of diagram and wording on booster seats for taller and/or heavier
children would also assist parents in selecting the proper seating
method to ensure protection. The law students suggested that the
packaging should indicate that children whose heads do not reach above
the windowsill should be restrained in a CRS.
Agency Response
NHTSA is declining these suggestions to adopt the measures in this
final rule. The agency would like to know more about the need for such
instructions and their effectiveness. NHTSA is conducting a research
program to determine a minimum boosting height for CRSs recommended for
children weighing more than 18.1 kg (40 lb). As a first step, NHTSA
evaluated the boosting height of current booster seat designs
recommended for children weighing more than 18.1 kg (40 lb). The
evaluation included posture and belt fit measures for 24 child
volunteers aged 4 to 12 seated in six different booster seat models
that were installed in 3 different vehicle models and in laboratory
seating conditions representing the range of cushion lengths and belt
geometries in later model vehicle rear seats.\116\ Among the program's
next steps, the research will seek to determine whether CRS seating
platforms should be at least a minimum height to position the head of
the child high enough to benefit from vehicle side impact protection
countermeasures. If a minimum boosting height can be determined, NHTSA
may consider rulemaking to specify a minimum boosting height. Results
from NHTSA's research will help inform the agency as to whether the
suggested warning label is merited for some CRSs.
---------------------------------------------------------------------------
\116\ Klinich, Kathleen D., Jones, Monica H., Manary, Miriam A.,
Ebert, Sheila H., Boyle, Kyle J., Malik, Laura, Orton, Nichole R.,
Reed, Matthew P., (2020, April). Investigation of potential design
and performance criteria for booster seats through volunteer and
dynamic testing (Report No. DOT HS 812 919). Washington, DC:
National Highway Traffic Safety Administration. Link: https://rosap.ntl.bts.gov/view/dot/49119.
---------------------------------------------------------------------------
VII. Aspects of the FMVSS 213a Test Procedure
NHTSA developed this final rule to replicate a vehicle-to-vehicle
intersection crash. NHTSA explained in the NPRM that this side impact
is best replicated in a test procedure that reflects the dynamic
elements of both the striking and struck vehicle in the crash. NHTSA
stated that a side impact test procedure should account for: (1) the
struck vehicle door velocity prior to the interaction of the striking
vehicle with the door sill of the struck vehicle, (2) the acceleration
profile of the struck vehicle, and (3) the impact angle to replicate
the longitudinal component of the direction of force. NHTSA concluded
that basing the specification of these parameters on actual vehicle
crash characteristics would enable the realistic simulation of the
relative velocity between the intruding door and the CRS. Accordingly,
the agency developed FMVSS No. 213a to simulate a full-scale vehicle-
to-vehicle side impact based on the MDB requirements of FMVSS No. 214,
``Side impact protection.'' \117\
---------------------------------------------------------------------------
\117\ As explained above in this document, FMVSS No. 214
specifies performance requirements for the protection of occupants
in side impact crashes. In a full-scale crash test representing a
severe intersection collision between two passenger vehicles, FMVSS
No. 214 requires passenger vehicles to protect occupants when the
vehicle is struck on either side by an MDB simulating an impacting
vehicle. The FMVSS No. 214 MDB crash test involves an MDB weighing
1,360 kg (3,000 lb), to represent a vehicle which is traveling at
48.3 kilometers per hour (km/h) (30 miles per hour (mph)) striking
the side of another vehicle which is traveling at 24 km/h (15 mph).
In the FMVSS No. 214 test, only the striking ``vehicle,''
represented by the MDB, is moving. Using vector analysis, the agency
combined the impact speed and impact angle data in crash files to
determine that the dynamics and forces of a crash in which a vehicle
traveling at 48.3 km/h (30 mph) perpendicularly strikes the side of
a vehicle traveling at 24.1 km/h (15 mph) could be represented by a
test configuration in which: the test vehicle is stationary; the
longitudinal centerline of the MDB is perpendicular to the
longitudinal centerline of the test vehicle; the front and rear
wheels of the MDB are crabbed at an angle of 27 degrees to the right
of its longitudinal centerline in a left side impact and to the left
of that centerline in a right side impact; and the MDB moves at that
angle and at a speed of 54 km/h (33.5 mph) into the side of the
struck vehicle.
---------------------------------------------------------------------------
Introduction
To simulate the side impact crash for purposes of testing CRS
performance, NHTSA proposed using a dynamic sled test based on an
acceleration sled system \118\ that was developed by Takata.\119\ The
Takata procedure is based on an acceleration sled with a test buck
consisting of a sliding ``vehicle'' seat (representative of a rear seat
designated seating position) mounted to a rail system, along with a
``side door'' structure rigidly mounted to the sled buck structure.
Aluminum honeycomb is mounted below the side door structure. The side
door is made to reach a desired velocity prior to the aluminum
honeycomb contacting the sliding ``vehicle'' seat structure. Together,
the sliding seat and door structure are referred to as the side impact
seat assembly (SISA). Figure 3 shows the Takata sled system test
procedure.
---------------------------------------------------------------------------
\118\ An acceleration sled is accelerated from rest to a
prescribed acceleration profile to simulate the occupant compartment
deceleration in a crash event. In comparison, a ``deceleration
sled'' is first accelerated to a target velocity and then is
decelerated to a prescribed deceleration profile to simulate the
same event.
\119\ See Docket No. NHTSA-2007-26833-0023 for a transcript of
the February 8, 2007 meeting where Takata gave a presentation on its
side impact test procedure. NHTSA also published two papers on the
agency's research and testing on the Takata test procedure (Sullivan
(2009) and Sullivan (2011), discussed infra).
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BILLING CODE 4910-59-P
[[Page 39258]]
[GRAPHIC] [TIFF OMITTED] TR30JN22.006
BILLING CODE 4910-59-C
NHTSA conducted three studies in advance of the NPRM to identify
test parameters that would adapt the Takata sled system for use in
FMVSS No. 213a. NHTSA's 2009 Initial Evaluation of Child Side Impact
Test Procedures \120\ used a modified Takata test buck to
[[Page 39259]]
develop test parameters that would simulate the FMVSS No. 214 test
procedure. The selected parameters were based on ten vehicles that had
previously been tested in accordance with FMVSS No. 214 and a series of
four full-scale crash tests. NHTSA concluded that the sled test
procedure appeared to be repeatable and could distinguish between child
restraint models using some of the injury measures. Comparison of
results from side impact sled tests using the Q3s dummy with comparable
full-scale vehicle side impact crash tests indicated that the dummy
responses exhibited similar trends in the sled and full vehicle crash
tests. NHTSA also announced its intention to perform further sled
testing to refine test parameters such as door stiffness and geometry,
and to further assess issues such as the effect of an armrest on CRS
kinematics and dummy responses.
---------------------------------------------------------------------------
\120\ Sullivan, L.K., Louden, A.E., ``NHTSA's Initial Evaluation
of Child Side Impact Test Procedures,'' 21st International
Conference on the Enhanced Safety of Vehicles, Paper No. 09-0539,
2009 [hereinafter Sullivan et al. (2009)].
---------------------------------------------------------------------------
The follow up to NHTSA's initial evaluation, NHTSA's 2011
Evaluation of a Potential Side Impact Test Procedure,\121\ presented
subsequent tests and vehicle surveys conducted to determine
characteristics of various components of side impact test bucks such as
the seat cushion, door panel, and an armrest that would result in
improved real world representation of the side impact sled test
procedure.
---------------------------------------------------------------------------
\121\ Sullivan, L.K., Louden, A.E., Echemendia, C.G. ``NHTSA's
Evaluation of a Potential Child Side Impact Test Procedure'' 22nd
International Conference on the Enhanced Safety of Vehicles, ESV
Paper No. 2011-0227, 2011 [hereinafter Sullivan et al. (2011)].
---------------------------------------------------------------------------
NHTSA also conducted a vehicle survey \122\ to examine the geometry
and contact characteristics of vehicle rear seats in order to select
the geometry and material characteristics necessary to replicate the
physical environment of a typical rear seat in a side impact test. The
2012 Vehicle Rear Seat Study recorded measurements of 43 individual
rear seating position in 24 model year 2010 vehicles to obtain
dimensional characteristics of rear seat attributes that could affect
the performance of CRS in the rear seat compartment. In addition, NHTSA
surveyed the features of vehicle child restraint anchorage systems in
furtherance of the agency's data on the systems. As discussed further
below, NHTSA relied on these measurements to create a rear seat
environment for the SISA that represented vehicles in the modern fleet.
---------------------------------------------------------------------------
\122\ Aram, M.L., Rockwell, T., ``Vehicle Rear Seat Study,''
Technical Report, July 2012. Docket No. NHTSA-2014-0012, Item No.
0005 (hereinafter 2012 Vehicle Rear Seat Study).
---------------------------------------------------------------------------
NHTSA's studies showed that the Takata-based test procedure
demonstrated versatility for tuning parameters to obtain the desired
test environment. NHTSA could tune the parameters to simulate the two-
vehicle side crash replicated in the MDB test of FMVSS No. 214. NHTSA
also noted that the test could be easily modified to change the impact
angle to introduce the longitudinal crash component present in the
FMVSS No. 214 tests. In addition, in its preliminary evaluation of the
Takata test protocol, after making minor modification to the test
parameters \123\ NHTSA determined that the test procedure was
repeatable and could provide results that distinguished between the
performance of various CRS models based on the design of the side wings
and stiffness of the CRS padding.\124\
---------------------------------------------------------------------------
\123\ Sullivan et al. (2009).
\124\ Sullivan et al. (2011).
---------------------------------------------------------------------------
Accordingly, based on the agency's research, NHTSA proposed a side
impact test for FMVSS No. 213a based on a refined and improved Takata
sled design. In addition, the NPRM proposed test specifications
developed by NHTSA ensuring the test procedure appropriately simulates
the FMVSS No. 214 MDB test, including the velocity of the striking
vehicle, the struck vehicle and the intruding door. Specifically, the
NPRM proposed the following specifications of the sled test to simulate
the FMVSS No. 214 MDB impact test of a small passenger car with the
child dummy restrained in a CRS positioned in the rear seat near-side
of the impact:
1. The test buck consists of a sliding seat mounted to a rail
system along with a ``side door'' structure rigidly mounted to the sled
buck structure. The sliding seat and side door are representative of
today's passenger vehicles. The sliding seat of this ``side impact seat
assembly'' (SISA) is positioned sufficiently away from the side door to
allow the sled to reach a desired velocity (31.3 km/h) prior to the
time the sliding seat starts to accelerate to a specific acceleration
profile.
2. The center of the CRS is positioned 300 mm from the edge of the
sliding seat next to the intruding door (simulating a near-side
position). At the time the sliding seat starts to accelerate, the
armrest on the door is located 32 mm (1.3 inches) from the edge of the
seat towards the CRS.
3. CRSs would be installed on the sliding seat using CRAS. Belt-
positioning seats covered by the NPRM would be tested using a lap and
shoulder belt on the sliding seat of the SISA.
4. NHTSA proposed injury criteria (expressed in terms of HIC15 and
chest deflection) for the Q3s. We proposed just to require head
containment of the 12-month-old CRABI (assess the ability of the CRS to
prevent the ATD's head from contacting the intruding door of the SISA).
In addition, the NPRM proposed to require CRSs to meet structural
integrity requirements when tested with the respective ATDs, and other
assorted performance criteria for belts and buckles.
a. Overview
In this final rule, NHTSA finalizes a test procedure that builds on
the SISA and test specifications proposed in the NPRM. The agency has
adjusted the final test procedure from that proposed in the NPRM, after
considering the comments, results of additional testing of the SISA,
and the agency's work on the proposed FMVSS No. 213 frontal test
procedures.\125\ As discussed further below, we modified the SISA to
minimize variability in installation, make the SISA equipment more
durable, and better match the proposed frontal FMVSS No. 213 seat
assembly. In addition, we further specified some of the side test
parameters, including a relative door velocity profile and the distance
of the door armrest to the vehicle seat, to improve the repeatability
and reproducibility of the test procedure. The final SISA and test
specifications are discussed below in turn.
---------------------------------------------------------------------------
\125\ See NPRM, 85 FR 69388, November 2, 2020, supra.
---------------------------------------------------------------------------
b. Side Impact Seat Assembly Characteristics
The side impact seat assembly (SISA) consists of a sliding
``vehicle'' seat mounted to a rail system, along with a side door
structure rigidly mounted to the sled buck structure. In the NPRM,
NHTSA described the agency's efforts to ensure that the sliding
``vehicle'' seat and side door would be representative of today's
passenger vehicles. Both NHTSA's initial evaluation studies and the
2012 Vehicle Rear Seat Study, discussed above, examined the geometry
and contact characteristics of present-day vehicle rear seats. The
agency used this information to design a seat assembly with the
geometry and material characteristics that were necessary to replicate
the physical environment of a typical rear seat relevant to the side
impact test. NHTSA identified the following rear seat features to
replicate in the SISA: (1) rear seat geometry (seat back angle, seat
pan angle, beltline height from approximately the vehicle seat bight
(i.e., the intersection of the seat cushion
[[Page 39260]]
and the seat back), height of the top of the armrest (from the seat
bight)), (2) rear seat cushion stiffness, and (3) door shape (height of
window, armrest thickness (protrusion of the armrest from the door
\126\)) and padding.
---------------------------------------------------------------------------
\126\ The original Takata sled buck did not include an armrest.
NHTSA modified the sled buck to include an armrest.
---------------------------------------------------------------------------
In addition, NHTSA performed a series of sled tests as a
sensitivity analysis to better understand the effect of the sled system
configuration on dummy responses.\127\ The parameters evaluated were
the seat cushion stiffness, door padding stiffness, presence of
armrest, and windowsill height.
---------------------------------------------------------------------------
\127\ Sullivan et al. (2011).
---------------------------------------------------------------------------
Based on the agency's research, NHTSA proposed using a SISA for the
FMVSS No. 213a test procedure that modified aspects of the original
Takata sled specifications to make the SISA better represent the rear
seat environment. Figure 4 shows the proposed SISA.
[GRAPHIC] [TIFF OMITTED] TR30JN22.007
The proposed SISA had the following specifications:
A single seating position representing a rear outboard
seating position.
Seat back and seat pan angles of 20 and 15 degrees,
respectively, which is the same as the original Takata buck. Both
angles were well within the ranges found in NHTSA's vehicle survey, and
those angles were the same as the ECE R.44 bench seat.
ECE R.44 rear seat cushion foam. NHTSA proposed using this
foam because it was more representative of the stiffness of current
rear seats in the vehicle fleet than other cushion foams surveyed
(FMVSS No. 213, NPACS). However, NHTSA also noted that sensitivity
studies showed seat foam cushion stiffness had little effect on dummy
responses in the side impact test procedure.
A 64 mm (2.5 inches) thick armrest attached to a 51 mm (2
inches) thick door panel. The armrest was a ``stiff'' foam (United Foam
#4), attached to an ``average'' stiffness foam padding door (Ethafoam
220). NHTSA stated that this configuration appeared to be
representative of the rear seat environment, and the armrest stiffness
using the ``stiff'' United Foam #3 was within the range of armrest
thickness of surveyed vehicles. Importantly, dummy responses with this
armrest/door configuration were similar to those seen in vehicle crash
tests.\128\
---------------------------------------------------------------------------
\128\ Sullivan et al. (2011).
---------------------------------------------------------------------------
A beltline height of 500 mm (19.6 inches). Although this
value was slightly higher than the average beltline height of vehicles
surveyed (489 mm), NHTSA proposed the 500-mm value to ensure that the
proposed side impact test was sufficiently stringent to account for
vehicle beltlines that were higher than the average value.
Lower anchorages of the CRAS symmetrically located on
either side of the centerline of the simulated outboard seating
position of the SISA bench seat. The location of the top tether
anchorage was on the lower rear frame of the seat, similar to the
typical location of a tether anchorage in captain's seats in minivans.
In addition to these aspects of the SISA that the agency discussed
in the preamble, NHTSA included detailed drawings of the SISA in the
docket for the NPRM, which further specified materials and measurements
of every part of the SISA.
While NHTSA welcomed comments on all aspects of the proposed rule,
the agency sought comment on specific aspects of the SISA, including
the proposed seat cushion foam and seat
[[Page 39261]]
cushion assembly. In addition, NHTSA had stated the agency had
initiated a research program to evaluate how the test parameters of the
FMVSS No. 213 frontal sled test should be updated to reflect any
significant real-world developments.\129\ The agency stated it planned
to develop a test bench seat with seat cushion stiffness that has
characteristics of seat cushions in recent vehicle models, pursuant to
MAP-21's mandate to amend the standard seat assembly specifications
under FMVSS No. 213's frontal test ``to better simulate a single
representative motor vehicle rear seat.'' \130\ NHTSA stated in the
NPRM for side impact \131\ that it would consider, to the extent
possible under the timeframes for the research and rulemaking programs,
the merits of using this updated frontal test seat cushion foam in the
side impact sled.
---------------------------------------------------------------------------
\129\ NHTSA Vehicle Safety and Fuel Economy Rulemaking and
Research Priority Plan 2011-2013 (Docket No. NHTSA-2009-0108-0032).
\130\ Quoting MAP-21, Sec. 31501(b), ``Frontal Impact Test
Parameters.''
\131\ 79 FR at 4586, col. 2.
---------------------------------------------------------------------------
Since publication of the 2014 NPRM, NHTSA continued to develop a
standard seat assembly for upgrading the FMVSS No. 213 frontal impact
sled test using the SISA sliding seat as a starting point. The November
2, 2020 NPRM proposing amendments to FMVSS No. 213 described the
agency's continued work updating aspects of the vehicle rear seat
environment, such as the seat back height, seat cushion stiffness, and
CRAS and seat belt anchorage locations, so that the frontal impact seat
assembly would be more representative of vehicle rear seats. The
proposed standard seat assembly for the frontal impact sled test is
similar to the proposed SISA sliding seat, although the proposed
frontal impact seat assembly has some more up-to-date specifications
for features such as the seat cushion thickness, seat back height and
anchorage locations. These differences were described in detail in the
November 2, 2020 NPRM.\132\
---------------------------------------------------------------------------
\132\ 85 FR at 69393.
---------------------------------------------------------------------------
In the November 2020 NPRM, NHTSA sought comment on whether the side
impact test seat assembly and the seat assembly proposed in the 2020
NPRM should be consistent.\133\ NHTSA stated in the November 2, 2020
NPRM that using the same specifications of the standard seat assembly
(including seat geometry, seat cushion, and anchorage locations) for
both the side impact test and a frontal impact test would make sense,
since the agency is seeking to test CRSs on a representative seat
assembly and the same passenger vehicles are involved in side and
frontal crashes.
---------------------------------------------------------------------------
\133\ Id., col. 2-3.
---------------------------------------------------------------------------
The agency also stated that the standard seat assembly proposed in
the January 2014 side impact NPRM is substantially like the seat
proposed in the November 2020 NPRM, but that NHTSA believes the seat
assembly proposed in the November 2020 NPRM is a better seat assembly
primarily regarding the cushion foam. NHTSA explained that the January
2014 NPRM specified use of the ECE R.44 seat cushion, while the
November 2020 proposed seat assembly incorporates seat cushion foam
that is more representative of the seat cushion stiffness of the
current vehicle fleet. NHTSA stated that the proposed seat cushion ``is
also easier to procure than the ECE R.44 foam. Commenters to the
January 2014 side impact NPRM expressed concerns about the difficulty
to source the ECE R44 seat foam, which is only available from one
overseas supplier. [Footnote omitted.] NHTSA tentatively believes that
using the foam specified in this NPRM for the frontal test seat
assembly would alleviate those concerns.''
Four commenters (Evenflo, Cybex, Graco and Consumer Reports) to the
November 2, 2020 frontal upgrade NPRM expressed support for having
consistent side and frontal impact test seat assemblies in FMVSS No.
213 and FMVSS No. 213a, respectively. Evenflo noted that using the same
seat assembly in both test methods will reduce variables in assessing a
CRSs. Cybex commented that having a more representative seat assembly
as the one proposed for the frontal impact sled test would be
beneficial to real-world crashworthiness. No commenter opposed having
consistency between the seat assembly used in the frontal and side
impact sled tests.
NHTSA is moving forward with a SISA that differs from the 2014
proposed SISA in some respects to make it more representative of rear
seats in the current vehicle fleet, to address comments, and to better
align the SISA with the proposed seat assembly for the FMVSS No. 213
frontal impact test. These structural changes and the agency's
responses to other comments on the SISA are discussed in detail, below.
Other minor modifications, like minor changes to accelerometer
placement and the addition of stiffening structures to reduce
vibrations, are discussed more at length in the ``FMVSS No. 213 Side
Impact Test Evaluation and Revision'' report included in the docket for
this final rule.\134\
---------------------------------------------------------------------------
\134\ Louden & Wietholter (2022).
---------------------------------------------------------------------------
NHTSA believes that the above modifications make the SISA better
representative of the rear seat environment and better able to
reproduce the characteristics of a side impact. In addition, these
modifications address comments on the availability and durability of
materials used in the SISA, and address comments on repeatability and
reproducibility of the final test procedure. Importantly, and as
discussed further below, NHTSA performed tests with the final SISA
configuration to compare the test results with those using the proposed
SISA, and concluded that test results with the updated SISA in this
final rule are not significantly different from those with the proposed
SISA. The following sections discuss comments on aspects of the sliding
seat, door, and maintenance of the SISA.
1. Seat Characteristics
i. Rear Seat Cushion Stiffness
To determine the stiffness of the seat foam for the proposed SISA,
NHTSA considered several data points. We considered the vehicle survey
that measured the rear seat cushion stiffness of 13 vehicles, as well
as the seat cushion stiffness of the seat cushions used in FMVSS No.
213, the United Nations Economic Commission for Europe, ``Uniform
provisions concerning the approval of restraining devices for child
occupants of power-driven vehicles (child restraint systems)'' (ECE
R.44), and the New Programme for the Assessment of Child Restraint
Systems (NPACS) \135\ programs.\136\ The results of the survey showed
that the FMVSS No. 213 foam was softer than all the vehicle seat foams
surveyed. The ECE R.44 and NPACS foams were stiffer than the FMVSS No.
213 foam, and more representative of the vehicles surveyed. However,
NHTSA's sensitivity analysis to determine the effect of the seat
cushion stiffness on dummy readings and CRS performance showed that
seat cushion foam stiffness had little effect
[[Page 39262]]
on the dummy responses in these side impact tests.
---------------------------------------------------------------------------
\135\ The NPACS consortium was funded in 2005 by governments of
the United Kingdom, the Netherlands, Germany, the Generalitat of
Catalonia, and five non-governmental organizations. The objective of
NPACS is to provide scientifically based EU wide harmonized test and
rating protocols to offer consumers clear and understandable
information about dynamic performance and usability of child
restraint systems. NPACS is similar to NHTSA's New Car Assessment
Program (NCAP), and to the NCAP program administered in Europe
(EuroNCAP), in that NPACS is a voluntary consumer information
program, rather than a binding regulation. (Note, however, that
NPACS is designed to test CRSs, while NCAP focuses on vehicle
performance.)
\136\ Sullivan et al. (2011).
---------------------------------------------------------------------------
Accordingly, NHTSA initially proposed that the seat cushion foam
for the SISA have the stiffness of the ECE R.44 seat foam, given that
the ECE R.44 foam was more representative of the current rear seats in
the vehicle fleet than the FMVSS No. 213 cushion foam. At that time,
NHTSA had not yet developed the NHTSA-Woodbridge seat cushion foam, so
NHTSA stated that the agency preferred the ECE R.44 foam over the NPACS
foam because although the two foams were similar in stiffness, the ECE
R.44 foam was more readily available than the NPACS foam. NHTSA invited
comment on this proposed seat cushion foam and seat cushion assembly.
NHTSA also stated that the agency had initiated a research program
to evaluate how the test parameters of the FMVSS No. 213 frontal sled
test should be updated to reflect any significant real-world
developments. Within this program, NHTSA planned to develop a test
bench seat with seat cushion stiffness characteristic of seat cushions
in recent vehicle models. NHTSA stated that the agency would consider,
to the extent possible under the timeframes for the research and
rulemaking programs, the merits of using this updated seat cushion foam
in the side impact sled.
Comments Received
CU, Dorel, Graco and UPPAbaby commented that the ECE R.44 foam was
appropriate for side impact testing. CU and UPPAbaby also suggested
including the same foam in the FMVSS No. 213 frontal impact test. CU
added that the ECE R.44 foam should be used in the frontal impact FMVSS
No. 213 test because a stiffer standard seat foam may result in larger
performance differences among CRSs than that with the current standard
seat assembly in the FMVSS No. 213 frontal impact test.
Relatedly, while MGA did not provide specific comments on the
proposed seat foam, MGA did state that there are few areas where FMVSS
No. 213 and FMVSS No. 213a could be harmonized with regards to the seat
cushion. Specifically, MGA stated that the cover material, foam insert,
and overall assembly for the seat cushion could be harmonized,
referencing FMVSS No. 213's leather type zippered cover over two softer
pieces of foam, compared to the FMVSS No. 213a's cloth type cover
wrapped over a single piece of stiffer foam. Similarly, Graco requested
that NHTSA consider the use of the same foam for frontal crash testing
as used in side testing in any future improvements to FMVSS No. 213.
An individual, Mr. Hauschild, commented that the seat foam needs to
be representative of the current vehicle fleet, and added that research
has shown that the foam of the FMVSS No. 213 standard seat assembly for
forward-facing seat testing reacts differently than vehicle
manufacturer seats and can influence the performance of the CRS (citing
Tylko et al., 2013 \137\). Graco agreed with the use of standard seat
foam that is more representative of current vehicles.
---------------------------------------------------------------------------
\137\ Tylko, S., Locey, C.M., Garcia-Espana, J.F., Arbogast,
K.B., & Maltese, M.R. 2013. Comparative performance of rear facing
child restraint systems on the CMVSS 213 bench and vehicle seats.
Ann Adv Automot Med 2013. 57, 311.
---------------------------------------------------------------------------
Britax, JPMA, and Graco noted the difficulty to source the ECE R.44
foam. Britax stated that while it did not oppose the use of the ECE
R.44 foam in principal, it strongly recommended that NHTSA survey the
marketplace to better determine the availability of this type of foam
for U.S. CRS manufacturers. Britax stated that the ECE R.44 foam is not
readily available and to require its use for side impact testing may
create a considerable hardship both from a cost and availability
perspective. Britax stated that supplying consistent foam for FMVSS No.
213 standard seat assembly requirements has been a challenge for all
CRS manufacturers who engage in internal sled testing. Britax explained
that it has always been difficult to source cost effective supplies of
foam that have the density, stiffness and qualities necessary for sled
testing. Britax suggested that, since the seat cushion foam stiffness
has minimal effect on dummy responses (as stated by the agency), it may
be a reasonable solution to continue to permit the use of FMVSS No. 213
seat cushion foam. Graco explained that various parties use different
types of foam due to the difficulty of sourcing the foam.
Britax and Graco also commented on the importance of having
sufficient foam specifications to source the foams. Britax stated that
it would be essential to specify foam density and content. Graco
requested that NHTSA provide clear seat foam drawings, material
definition, indentation load-displacement (ILD) properties and a seat
foam test methodology.
JPMA commented that all members were concerned with viable
competitive test equipment sourcing and availability and that it
believed a single source and supply with no competition is untenable.
Agency Response
NHTSA's research program to develop a standard seat cushion with
similar characteristics of seat cushions in more recent vehicle models
resulted in the development of a foam, referred to as the ``NHTSA-
Woodbridge'' \138\ seat cushion foam,\139\ that the agency proposed to
use in the November 2, 2020 NPRM to upgrade the frontal impact seat
assembly. In that NPRM, NHTSA noted that after additional research and
testing,\140\ the agency determined that the ECE R.44 and NPACS seat
foam stiffness were not representative of the U.S. vehicle fleet (in
both quasi-static and dynamic stiffness). Specifically, Figure 5 below
shows that the ECE R.44 and NPACS foams were found to be stiffer than
the vehicle fleet. The FMVSS No. 213 foam, tested on the standard seat
assembly with a cover, is on the low end of the vehicle fleet rear seat
stiffness. The NHTSA-Woodbridge seat cushion shows an average dynamic
stiffness response compared to the vehicle rear seats sample.
---------------------------------------------------------------------------
\138\ The Woodbridge Group is a supplier of automotive seat
foam, http://www.woodbridgegroup.com.
\139\ The NHTSA-Woodbridge seat cushion consists of the foam
material covered by the cover used in test procedures of ECE R.44.
The ECE R.44 cover material is a sun shade cloth made of poly-
acrylate fiber with a specific mass of 290 (g/m\2\) and a lengthwise
and breadthwise breaking strength of 120 kg (264.5 pounds) and 80 kg
(176.3 pounds), respectively.
\140\ Wietholter, K., Louden, A., Sullivan, L., & Burton, R.
(2021, September). Evaluation of seat foams for the FMVSS No. 213
test bench. Washington, DC: National Highway Traffic Safety
Administration.
---------------------------------------------------------------------------
[[Page 39263]]
[GRAPHIC] [TIFF OMITTED] TR30JN22.008
NHTSA is adopting the NHTSA-Woodbridge seat cushion foam in the
SISA because it has characteristics that best represent an average
vehicle rear seat in the United States. In addition, the NHTSA-
Woodbridge seat cushion foam is easier to procure than the ECE R.44
foam proposed for use in the 2014 NPRM. To simplify procurement of the
desired seat cushion foam, NHTSA's FMVSS No. 213 Side Impact Test
Evaluation and Revision report sets forth characteristics of the NHTSA-
Woodbridge seat cushion foam.\141\ Further details of seat cushion
characteristics are available in the drawings that are in the docket
for this final rule. In response to Britax, Graco, and JPMA's concerns
about the ability to source cost-effective seat cushion foam, NHTSA
launched a program to identify foam manufacturers and has found four
sources that can provide the specified foam. These sources are
available in the report, ``Foam Feasibility Study,'' \142\ that is
available in the docket for this final rule.
---------------------------------------------------------------------------
\141\ Louden & Wietholter (2019).
\142\ ``Foam Feasibility Study by National Center for
Manufacturing Sciences'' (NHTSA, June 2018). This document is in the
docket for this final rule.
---------------------------------------------------------------------------
In response to MGA's comment that the seat cover material, foam
insert, and overall assembly for the seat cushions could be harmonized
between FMVSS No. 213 and 213a, the agency has taken steps to keep
FMVSS No. 213a as harmonized as possible with the FMVSS No. 213 frontal
seat assembly proposed on November 2, 2020. This includes the cover
material, foam insert, and overall assembly of the seat cushions. NHTSA
agrees that there are benefits to harmonizing FMVSS No. 213 and 213a to
the extent possible, and that it makes sense that the seat assembly
used to represent vehicle seats in the side crash test would be similar
to the seat used in the frontal test.
While CU, Dorel, Graco and UPPAbaby considered the ECE R.44 seat
foam appropriate for side impact testing, NHTSA's additional research
shows that the ECE R.44 foam is stiffer than an average vehicle rear
seat. The NHTSA-Woodbridge foam is softer than the ECE R.44 foam and is
a good representation of the average cushion stiffness of rear seats in
the current vehicle fleet. This also accords with Mr. Hauschild and
Graco's suggestion to have a seat foam that is representative of the
current vehicle fleet.
In the November 2, 2020 NPRM upgrading the FMVSS No. 213 frontal
impact seat assembly, NHTSA proposed the NHTSA-Woodbridge seat cushion
foam thickness of 4.0 0.5 inches (101.6 12.7
mm). JPMA and Graco expressed concern regarding the proposed tolerance
of the seat cushion thickness in their comments to the November 2, 2020
NPRM, noting that the proposed tolerance in the seat cushion thickness
(0.5 inches (12.7 mm)) could result in
increased test variability. JPMA reiterated its concerns regarding the
proposed tolerance in the seat cushion foam thickness in a meeting with
NHTSA on December 15, 2021,\143\ and provided sled test results showing
variability in performance measures when tested with seat foam
thicknesses ranging between 3.67 to 4.42 inches (93.2 to 112.3 mm).
NHTSA agrees with the commenters on this issue and sees merit in
reducing the tolerance of the seat cushion thickness to a level that
would reduce variability in testing, while also ensuring availability
of foam that meets specifications. After reviewing all available
information, NHTSA is specifying a NHTSA-Woodbridge seat cushion foam
thickness of 4.0 0.25 inches (101.6 6.35 mm).
This change is reflected in the drawing package incorporated by
reference by this final rule.
---------------------------------------------------------------------------
\143\ We submitted a memorandum summarizing this meeting to
Docket No. NHTSA-2014-0012.
---------------------------------------------------------------------------
Due to the change in seat cushions from the ECE R.44 foam (which is
127 mm (5 inches) thick) to the NHTSA-Woodbridge cushion (which is
101.6 mm (4 inches) thick), NHTSA modified the SISA to account for
changes to the seat cushion height. Using a thinner seat cushion
lowered the position of the installed CRS on the seat assembly with
respect to the door and armrest height, so the agency lowered the
position of the door and armrest by about 25.4 mm (one inch) so that
their relative position with respect to the installed CRS in the seat
assembly are the same as that in the
[[Page 39264]]
2014 proposal (which is representative of the current vehicle fleet).
This is discussed further in the section below on the SISA's door and
armrest thickness and stiffness.
ii. Lower Anchorages and Top Tether Anchorages of the CRAS
FMVSS No. 213 currently requires CRSs to be capable of being
secured to a vehicle seat with the child restraint anchorage system
(CRAS), and to meet the frontal crash requirements of the standard when
using the CRAS. A CRAS consists of two lower anchorages and one upper
tether anchorage. Each lower anchorage includes a rigid round rod or
``bar'' onto which a hook, a jaw-like buckle or other connector can be
snapped. The bars are located at the intersection of the vehicle seat
cushion and seat back. The upper tether anchorage is a ring-like object
to which the upper tether of a CRS can be attached. (FMVSS No. 213 also
requires that CRSs must be capable of being secured to a vehicle seat
using the vehicle's seat belt system.)
NHTSA proposed that CRSs covered in the proposal, other than belt-
positioning seats, meet the side impact performance requirements when
attached to the SISA with the lower attachments of the CRAS. NHTSA also
proposed that forward-facing CRSs supplied with a top tether may have
that top tether attached during testing if the written instructions
accompanying the CRS instruct owners to attach the top tether when
using the restraint. As discussed further in a section below, NHTSA has
adopted the above provisions in the test procedure for this final
rule.\144\ This section discusses the proposed specifications for the
CRAS lower anchorages and top tether anchorages on the SISA, comments
received, and the final specification of the anchorages.
---------------------------------------------------------------------------
\144\ NHTSA has also adopted a requirement that CRSs be tested
with a Type 2 seat belt (lap and shoulder belt) with the child
restraint system's top tether attached, if provided.
---------------------------------------------------------------------------
NHTSA proposed that the SISA be equipped with 2 inches (50.8 mm)
wide CRAS lower anchorages that were symmetrically located on either
side of the centerline of the simulated ``outboard seating position''
of the SISA seat. NHTSA proposed that the top tether anchorage be
located on the lower rear frame of the seat, similar to the typical
location of a tether anchorage in captain's seats in minivans. The
exact locations of the proposed CRAS lower anchorages and tether
anchorages were included in drawings posted to the docket for the NPRM.
Comments Received
UMTRI commented that the width of the lower anchor bars on the buck
appeared to be 2 inches, rather than the 1-inch minimum required in
FMVSS No. 225, ``Child restraint anchorage systems,'' and most commonly
used by vehicle manufacturers. UMTRI noted that in the NPRM, NHTSA
stated that a European side impact test method was not suitable for
testing U.S. products because it allows the connectors to slide. The
commenter believed use of a 2-inch wide anchor rather than a 1-inch
wide anchor may have the same effect and be unrealistic relative to the
U.S. market.
MGA provided comments identifying potential interference of the
SISA intruding door with the anchorage locations. First, MGA identified
that because the lower anchor assembly protrudes through the seat
bight, it was found to contact some CRS bases during their testing. In
addition, MGA stated that the lower anchor assembly interferes with
both the corner of the door fixture and the bottom of the seat cushion.
MGA suggested that if the NPRM specifications for lower anchor location
were desirable, the cushion foam design could be adjusted to
accommodate the anchor, or the designed cutout in the seat foam could
be made smaller and still provide clearance for the anchor assembly.
MGA believed that a smaller cutout would provide the benefit of a
larger area for the CRS to sit during the test.
Agency Response
Modifications to the SISA have resulted in some changes to the
lower anchorages. First, in response to MGA's comment, NHTSA updated
the lower anchor location and cushion design and specifications to
eliminate the lower anchor interference with CRS bases, corner of the
door fixture, and seat foam. NHTSA also eliminated the foam cutouts, as
discussed further below. In making these modifications, NHTSA also made
the SISA lower anchorage locations consistent, as practically possible,
with the lower anchorage locations in the proposed standard seat
assembly of the frontal impact sled test. In addition, NHTSA decreased
the anchorage width to 1.5 inches (38.1 mm). This is wider than those
generally found in vehicles, but is within the 60-mm maximum allowable
anchorage width specified in FMVSS No. 225. Because the standard seat
assembly is used repeatedly and the anchorages will be subjected to a
crash environment repeatedly, the new lower anchorages were made more
robust than the anchorages in a vehicle, and designed in a way that
allows easy replacement when the anchorages are deformed.
In response to UMTRI, while these wider anchorages may allow some
movement of the CRS on the sliding seat assembly during the impact, the
movement is slight and nowhere comparable to the European sliding
anchors that allow 200-250 mm (7.87-9.84 inches) of movement. NHTSA has
not measured the displacement of the CRS on the seat assembly during
the impact event; however, in the 2014 NPRM the agency compared the
dummy kinematics and injury measures in the side impact sled test to
that in a vehicle side impact test and found them to be similar. NHTSA
believes the effect of this sliding due to the length of the anchorage
is minimal.
Comments Received
SRN requested that the proposed tether anchor location be further
reviewed because a tether anchor located lower on the back of the seat
has been shown to be less effective in far side impact testing.\145\
SRN argued that using a high tether anchor position on the proposed
SISA would have an additional benefit even if it were not required for
compliance in near side crashes. SRN stated that this would simplify
the process for manufacturers to conduct voluntary center and far-side
impact testing using a SISA configuration that more closely resembles
the real world. Similarly, UMTRI questioned why the top tether location
on the SISA was located on the lower seat back, instead of on a
location representing the rear filler panel, as with the FMVSS No. 213
frontal impact standard seat assembly. UMTRI also argued that top
tether anchorages located on the rear filler panel is more commonly
found in vehicles. MGA commented that the tether placement for FMVSS
No. 213a is located in a position that most closely resembles the floor
of a vehicle, while the tether anchor location for current FMVSS No.
213 is in a location that most closely resembles a top shelf. MGA
stated that while tether placement differs in all vehicle makes and
models, FMVSS No. 213 and 213a should have similar locations for the
tethers.
---------------------------------------------------------------------------
\145\ Klinich et al. ``Kinematics of the Q3s ATD in a Child
Restraint under Far-Side Impact Loading, Paper #05-0262.
---------------------------------------------------------------------------
Agency Response
This final rule adopts the proposed location of the tether
anchorage. As discussed above, the SISA tether anchorage is located on
the lower rear
[[Page 39265]]
frame of the seat and is similar to the typical location of a tether
anchorage in captains' seats in minivans. The 2012 Vehicle Rear Seat
Study found that 45% of the tether anchors were found on the rear shelf
location, 40% were found on the seat back, 10% were located on the
roof, and 5% in other locations. While a tether anchorage on the rear
shelf was found more frequently in the vehicle survey, the agency
decided to locate it on the seat back for several reasons. First, NHTSA
considered that tether use had no substantive effect on CRS performance
in the near-side impact test, because the simulated door impacts the
CRS before the tether has significant engagement.\146\ Further, a
longer distance to the tether anchorage (as found in a seat back tether
anchorage position compared to one located in the rear shelf) in a
frontal test may result overall in a more stringent test as the tether
may experience more webbing elongations when attached to the seat back
vs. the rear shelf. Also, NHTSA is interested in keeping the frontal
and side impact standard seat assemblies as similar as possible, and
agrees with MGA that the FMVSS No. 213 and 213a seat assemblies have
similar locations for the tethers. Therefore, the agency decided to
keep the tether anchorage locations in a seat back position in both
seat assemblies.
---------------------------------------------------------------------------
\146\ While there may be no effect of tether use and/or tether
anchorage position in a near side impact, use of a tether may
improve the repeatability of the test. Also, there may be some
effect of tether use in center and far-side impact environments,
which would be relevant to researchers conducting center and/or far-
side impact testing. Such testing would likely involve changing the
SISA and door assembly to resemble a center/far-side environment,
and adapting the SISA in such a manner would require substantial
changes to the sliding seat (i.e. making it wider to represent the
center and/or the far-seating positions in a rear seat) and/or to
the door assembly to position the door intrusion at an appropriate
distance for a center/far-side impact environment. Entities engaged
in such modifications can also consider changing the location of the
tether as part of their evaluation.
---------------------------------------------------------------------------
The lower anchorage locations from the 2012 Vehicle Rear Seat
Survey, the proposed child restraint anchorage locations to the frontal
impact test seat assembly,\147\ and the updated side impact assembly
are shown in Table 16.
---------------------------------------------------------------------------
\147\ 85 FR 69388, supra.
Table 16--Lower Anchors and Tether Anchor Locations From (1) the 24 Vehicle Survey, (2) the Proposed FMVSS No.
213 Frontal Impact Sled Test Standard Seat Assembly, and (3) the Final Side Impact Seat Assembly Configuration
(All Measurements are in Millimeters From Point A 148 of the Seat Geometry Measuring Fixture (SGMF))
----------------------------------------------------------------------------------------------------------------
Final side
Average from vehicle Proposed frontal test seat test seat
survey assembly (2020) assembly
----------------------------------------------------------------------------------------------------------------
Lower Anchors:
Aft................................. 100 21....... 58........................ 60
Lateral............................. 137 29....... 140....................... 141
Vertical (-) Below point A.......... -12 24....... -38....................... -39
Tether Anchors (Seat Back Position): ..........................
Aft................................. 280 88....... 330....................... 324
Lateral............................. 0 44......... 0......................... 5
Vertical (-) Below point A.......... 140 281...... 133....................... 133
----------------------------------------------------------------------------------------------------------------
UMTRI commented that to allow access to lower anchors, there is a
large gap between the bottom of the seatback foam and the top of the
seat cushion foam on the seat buck. UMTRI explained that when used with
some rear-facing child restraints, the profile of the restraint surface
that rests against the seatback may slip into the gap in an unrealistic
manner. UMTRI added that in the ECE buck, there is space between the
two foam segments, but the seatback foam is angled so there is some
foam in the gap. UMTRI stated that this provides a more realistic
seatback contour than the proposed SISA buck design.
---------------------------------------------------------------------------
\148\ The 2012 Vehicle Rear Seat Study measured the vehicles'
seat geometry and anchorage locations using a seat geometry
measuring fixture (SGMF). The SGMF consisted of two wood blocks (600
mm x 88 mm x 38 mm) and a 76 mm (3 inches) hinge. To make the rear
seat geometry measurements, the SGMF was positioned on the
centerline of each rear seat position. Point A, which corresponds to
the hinge location of the SGMF, was the reference point for all
measurements.
---------------------------------------------------------------------------
By way of background, NHTSA designed the side and frontal sled test
seat assemblies taking into consideration the current difficulties to
install and to measure installation tensions (seat belt and lower
anchor). The updated design has proven to allow for easier installation
in the buck and in some cases reduced the difficulty of measuring
installation tension. During extensive side and frontal impact testing
with the updated seat assemblies that have a gap in the seat bight
(between the seat back and seat cushion foam), the agency has not seen
any issues in CRS placement or during testing as mentioned by UMTRI.
Among more than 200 tests conducted on the side impact sled system with
rear-facing and forward-facing CRSs, NHTSA did not experience any
issues with the seat bight gap. Accordingly, this final rule does not
make the requested change.
2. Door Characteristics
i. Beltline Height
NHTSA proposed a beltline (window sill) height of 500 mm (19.6
inches) for the SISA, based on a survey of 24 vehicles. Although the
proposed beltline height (500 mm) was slightly higher than the average
(494 mm) and median (489 mm) beltline heights of the surveyed vehicles,
HIC values were generally higher at the higher beltline height. NHTSA
proposed the higher value to ensure that the side impact test was
sufficiently stringent to account for vehicle beltlines higher than the
average value. Child restraint systems meeting the HIC15 requirement
when tested against the 500 mm beltline will likely provide sufficient
crash protection in vehicles with a lower beltline, but the opposite
may not be valid. CRSs tested against a lower belt line might not
adequately protect children in vehicles with the higher (500 mm)
beltline design.
Comment Received
CU stated that the NPRM's fleet study of seats seemed to have been
conducted at the 479 mm (18.8 inches) height and that even at that
lower height, 7 of 12 forward-facing CRSs had HIC15 values in excess of
the proposed 570 limit. CU stated, ``Though the five seats with the
lower HIC15 had a notable margin between their values and the 570
limit, it may be an expectation that at the higher beltline height more
CRSs would approach or exceed that limit.'' CU added that the higher
beltline may also
[[Page 39266]]
produce a larger differential when compared to the performance of seats
in the sled/vehicle test comparison.
Agency Response
Contrary to CU's understanding, our fleet testing of forward-facing
CRSs discussed in the NPRM \149\ were performed at the higher beltline
height (500 mm or 19.6 inches), not the lower beltline height (479 mm
or 18.8 inches) that was first used during development. Tested against
the 500 mm beltline height, the fleet test results of forward-facing
CRSs with the Q3s dummy showed that 7 out of 12 CRSs exceeded HIC15
injury limits and that 3 out 12 tests resulted in chest deflection
exceeding the proposed limit (23 mm). Fleet tests of rear-facing CRSs
tested with the Q3s showed that 3 out of 5 exceeded HIC15 injury limits
and 2 out of 5 exceed chest deflection injury limits. For the 5 rear-
facing CRSs tested, the results of the fleet tests showed that the Q3s
measured HIC15 greater than 570 in 3 of the 5 rear-facing CRSs tested,
and chest deflection greater than 23 mm in 2 of the 5 tests. The Q3s
measured both HIC15 greater than 570 and chest deflection greater than
23 mm in 1 of the 5 rear-facing CRSs tested.
---------------------------------------------------------------------------
\149\ Id. at 4593.
---------------------------------------------------------------------------
Tests with the 12-month-old CRABI dummy in rear-facing CRSs showed
that the different beltline heights did not affect dummy responses.
NHTSA believes this was due to the fact that most rear-facing CRSs
designed for smaller children position the head lower (mostly below the
beltline) and therefore the increased height (at 500 mm or 19.6 inches)
did not affect the outcome. For this reason, fleet testing with the 12-
month-old CRABI dummy in rear-facing CRSs did include tests done at 500
mm and at 479 mm. Results of rear-facing CRSs using the 12-month-old
CRABI dummy showed that only 1 out of 12 models had head to door
contact. NHTSA believes the tests selected for the fleet testing and
cost benefit analysis in the NPRM were appropriate and accounted for
the increased stringency of the higher beltline. Accordingly, NHTSA is
not making any changes to the SISA beltline height from that proposed
in the NPRM.
ii. Door and Armrest Thickness and Stiffness
NHTSA proposed that the door panel/armrest configuration for the
SISA would consist of 51 mm (2 inches) ``average'' stiffness foam
padding (Dow Ethafoam 220) on the door and a 64 mm (2.5 inches)
``stiff'' foam (United Foam #4) for the armrest. NHTSA determined that
this door panel/armrest configuration had similar characteristics to
those observed in Free Motion Headform (FMH) impact testing of eight
vehicle doors. Those tests are described in detail in NHTSA's 2013
report, Child Restraint Side Impact Test Procedure Development.\150\
The proposed armrest thickness also fell within the range of vehicle
armrests measured in the 2012 Vehicle Rear Seat Study.
---------------------------------------------------------------------------
\150\ Sullivan, L., Louden, A., Echemendia, C., ``Child
Restraint Side Impact Test Procedure Development'' (December 2013),
available at Docket No. NHTSA-2014-0012-0002 [hereinafter Sullivan
et al. (2013)].
---------------------------------------------------------------------------
In addition to the representativeness of that door panel/armrest
configuration of average rear seat characteristics, NHTSA stated that
the proposed door padding (Ethafoam 220) was of lower cost compared to
the other foams, was relatively easy to obtain commercially, and was
relatively fungible, in that other materials with similar physical
properties could easily be used in its place. NHTSA also cited to
results of its sensitivity analyses that showed door stiffness had
little effect on dummy performance.\151\
---------------------------------------------------------------------------
\151\ Sullivan et al. (2011).
---------------------------------------------------------------------------
Discussion of Comments
CU commented that the FMVSS No. 201 test procedure that NHTSA used
as a basis for determining average door and armrest stiffness was also
utilized by CU in its revised CRS testing protocol, and therefore CU
supported that aspect of the NPRM. ARCCA commented that while it did
not have data to confirm or deny the appropriateness of the door/
armrest configuration, it was unaware of any rear door configuration
with the level of padding specified for the proposed SISA. ARCCA stated
that, accordingly, the HIC values acquired from head to door impact
would likely underpredict the severity of the head impact.
NHTSA disagrees with ARCCA. The stiffness of the simulated door in
the SISA is representative of the stiffness found in vehicles, which
NHTSA determined using the FMH testing described above. The stiffness
of the 51 mm thick door padding includes the combined stiffness of the
door assembly (inner and outer panel of the door) and the interior door
padding. The relevant factor for the test is door stiffness and not the
thickness of the door padding. Details of the development of the door
characteristics can be found in the ``Child Restraint Side Impact Test
Procedure Development'' technical report.\152\
---------------------------------------------------------------------------
\152\ Sullivan et al. (2013).
---------------------------------------------------------------------------
Both JPMA and MGA noted a discrepancy between the NPRM
specification for door foam thickness (51 mm) and the drawing package
specifications (55 mm). JPMA stated that this difference in foam
thickness is significant because ``the NPRM includes set-up distances
from the face of the door panel to the face of honeycomb material and
from the face of the honeycomb material to the centerline of the
sliding seat [sic].'' JPMA explained that the thickness of the foam is
thus an important part of these set-up relationships and needs to be
the same in the final rule and the drawing package to help ensure
consistent test results between test facilities. MGA stated that it
believed the error was on the part of the drawings, as 55 mm (2.2
inches) foam is not commonly available.
NHTSA agrees with MGA that there are inconsistencies in the door
foam thickness specification between the NPRM and the drawing package.
The door foam was procured as a 2-inch nominal thickness foam plank.
According to the foam manufacturer's terminology,\153\ an X-inch
nominal foam thickness means that the foam plank is gauged at a desired
thickness of X + \1/4\ inches. Therefore, a 2-inch nominal thickness
foam plank has a thickness of 57 mm (2.25 inches). Accordingly, NHTSA
has changed the door foam thickness measurements in Drawing 2921-501
from 55 mm (2.2 inches) to 57 mm (2.25 inches). The specified foam,
with a thickness of 57 mm (corresponding to a 2-inch nominal foam
thickness) is commonly available. Graco made several recommendations
relating to the door foam's characteristics over time and extended use.
The commenter recommended replacement of the door foam only after
significant structural damage. It recommended that NHTSA provide a
standardized method for measuring the compression properties of the
door foam. Graco provided developmental test results showing that
maximum HIC15 and chest deflection results occur at the time of contact
with the door structure.\154\ Graco suggested that NHTSA should confirm
that performance after extended use does not change results. Graco
explained that currently the foam types are described as ``Soft''
(United Foam # 2), ``average'' (Dow Ethafoam 220), and ``stiff''
(United Foam # 4) foam. Graco suggested that, if these descriptions can
also include a method for confirming compression
[[Page 39267]]
properties after extended use, crash test facilities can confirm that
injury metric results are not affected by changes in foam properties.
---------------------------------------------------------------------------
\153\ Link to foam manufacturer's terminology: https://www.customfoaminc.com/CustomFoamProductsSpecSheet.pdf.
\154\ NHTSA-2014-0012-0042, at pg. 9.
---------------------------------------------------------------------------
MGA reported that they did not replace the door and armrest foam
between tests (approximately 40 tests). MGA used a single piece for the
door and two pieces for the armrest attached with spray adhesive. MGA
reported that the foam assembly did not show any physical degradation
nor change in thickness during their test series.
During NHTSA's research testing, the door foam was reused for 2 to
3 tests as no extensive damage was seen during initial tests, while the
armrest foams were used only once as they presented indentations from
the impact of a single test. Since there is no method to retest for the
compression properties of the door and armrest foams after use, NHTSA
frequently replaces these foams.\155\ How frequently NHTSA will replace
these foams in its compliance testing program will be indicated in
NHTSA's compliance test procedure for FMVSS No. 213a that will be
included on NHTSA's website.\156\
---------------------------------------------------------------------------
\155\ The research test procedure developed at VRTC specifies
use of a new foam for each test. This test procedure is in the
following report in the docket of this final rule: Louden, A., &
Wietholter, K. (March 2022). FMVSS No. 213 side impact test
evaluation and revision (Report No. DOT HS 812 791). Washington, DC:
National Highway Traffic Safety Administration (hereinafter Louden &
Wietholter (20)).
\156\ The NHTSA Office of Vehicle Safety Compliance FMVSS No.
213a side impact test procedure can be found at: https://www.nhtsa.gov/vehicle-manufacturers/test-procedures.
---------------------------------------------------------------------------
3. Honeycomb
As discussed above, the purpose of honeycomb on the door structure
is to contact the sliding seat in a way that the desired sliding seat
acceleration is achieved. NHTSA included honeycomb specifications in
the parts list drawings docketed with the NPRM. The drawing specified
Aluminum--6061 (AL 6061) as the material used, the honeycomb cell size,
foil gage, and density, and noted that an equivalent density could be
used. The drawings also specified the dimensions of the honeycomb used
in the test sled.
JPMA was concerned that the costs of running the proposed side
impact test would be higher than running an FMVSS No. 213 frontal
impact test because the honeycomb material could only be obtained from
one supplier and that the limited availability drove up demand and
price. JPMA added that the honeycomb material could only be used once
and then must be discarded. JPMA recommended NHTSA specify the type of
material that could be used and the amount of pre-crush that should be
done to allow for technological advances in this area without
restricting potential suppliers.
JPMA also commented that testing by its members using honeycomb
material with and without pre-crush confirmed that the performance of
the honeycomb varied. JPMA added that the pre-crushed material produced
lower peak Gs and a lengthened, smoother deceleration pulse. JPMA
believed that even if the final rule specified pre-crushed honeycomb,
it also must include parameters for controlling the amount of crush to
be obtained and whether the pre-crushed surface of the honeycomb
material should face the sliding seat.
Agency Response
As discussed above, for the final rule's test procedure, NHTSA made
changes to the sliding seat structure to reduce vibrations that were
affecting accelerometer readings and to align the seat specifications
with that of the proposed FMVSS No. 213 frontal impact test.\157\ These
modifications added weight to the sliding seat structure, and the added
weight of the seat made the sliding seat acceleration pulse fall to the
lower bound of the proposed acceleration corridor of the sliding seat
assembly. Therefore, the specifications for the honeycomb needed
revisions to obtain the average acceleration pulse in the sled tests
presented in the NPRM.
---------------------------------------------------------------------------
\157\ 85 FR 69388, supra.
---------------------------------------------------------------------------
The agency worked with Plascore, the manufacturer of the honeycomb
used in the proposed SISA, to select a honeycomb for testing purposes
that would modify the sliding seat response and bring the acceleration
pulse within the proposed corridor. NHTSA also worked to develop
appropriate specifications for the selected honeycomb material. The
final honeycomb specifications differ in cell size and crush strength
from the proposed specifications. The final honeycomb specifications
are detailed in a report entitled, ``FMVSS No. 213 Side Impact Test
Evaluation and Revision,'' \158\ in addition to the drawing package
accompanying this final rule.
---------------------------------------------------------------------------
\158\ Louden & Wietholter (2022).
---------------------------------------------------------------------------
In response to JPMA's concerns that the honeycomb could only be
obtained from one supplier, while the agency did not test with
honeycomb from different sources, the agency notes that Cellbond is
another manufacturer that can provide similar honeycomb material. In
addition, if manufacturers are concerned about the cost of replacing
the honeycomb, they can develop their own decelerating system (e.g. a
hydraulic decelerator) that provides a sliding seat acceleration
profile within the required acceleration corridor. The honeycomb
specification is provided to advise manufacturers how NHTSA's
compliance tests will be performed, but manufacturers are not required
to use the procedures. NHTSA also notes that the size and crush
strength of the honeycomb can help tune the system to achieve the
desired accelerations within the corridor.\159\
---------------------------------------------------------------------------
\159\ See Louden & Wietholter (2022). See also Brelin-Fornari,
J., ``Final Report on CRS Side Impact Study of Repeatability and
Reproducibility using a Deceleration Sled,'' July 2017.
---------------------------------------------------------------------------
The agency also tested some pre-crushed honeycomb but found, as
JPMA had noted in its comments regarding members' testing, that the
acceleration pulse peak was reduced and the length of the pulse
extended outside the proposed acceleration corridor.\160\ As NHTSA
found that it was possible to obtain an acceleration pulse of the
sliding seat that was within the specified corridors using honeycomb
that was not pre-crushed, NHTSA did not further consider the use of the
pre-crushed honeycomb. However, as discussed above, the standard
adopted by this final rule does not prohibit the use of pre-crushed
honeycomb. Test facilities and manufacturers may choose any type of
honeycomb as long as the sliding seat acceleration pulse is within the
specified corridors. They may even use an entirely different apparatus
(e.g., a hydraulic decelerator, which does not require honeycomb) as
long as their child restraints meet FMVSS No. 213a when tested by NHTSA
in the manner specified in the standard.
---------------------------------------------------------------------------
\160\ Louden & Wietholter (2022).
---------------------------------------------------------------------------
4. SISA Technical Drawings
The NPRM proposed to incorporate by reference a set of technical
drawings of the SISA into FMVSS No. 213a. The technical drawings were
placed in the docket. Several commenters provided feedback on the
drawings, pointing out errors such as minor discrepancies between the
drawing and the proposed regulatory text, places where clarity was
requested, and suggestions for additional drawings or parts
specifications for the SISA. NHTSA has provided additional explanation
in the discussion below, and in some cases, has made minor corrections
or revisions to the drawings to correct or clarify the material. These
changes simply improved the quality of the drawings and will have no
effect on the outcomes of the test.
[[Page 39268]]
Corrections and Revisions to the Technical Drawings
MGA suggested that the agency incorporate drawings or reference
geometry for a D-ring and Type 2 (3 point) seat belt anchors. MGA
stated that currently different test facilities use different methods
for locating and attaching belt anchors, which the commenter believes
has been a source of concern with FMVSS No. 213. MGA stated that ECE R.
44 Annex 13, p. 149-151 (dated February 2008), specifies geometry and
may be helpful as a reference as the proposed SISA has similar geometry
to the ECE R44 seat assembly. In response, NHTSA has included drawings
for the D-ring and Type 2 belt anchors in the final drawing package.
MGA suggested removing the CRAS lower anchorages and belt anchor
assembly from inside the bottom cushion to allow a complete bottom
cushion with no cutouts. MGA stated that this would provide the ability
to have a more consistent and representative seating surface. In
response, as discussed above, the final foam design does not have
cutouts, and the anchorages location and design have been updated to be
more accessible and durable. The specific change MGA suggested has not
been made.
MGA commented that although load legs are not currently recognized
in FMVSS No. 213, some sort of platform in a specified location on the
SISA may help aid their introduction into FMVSS No. 213 in the future.
Relatedly, CU commented that during its evaluation of infant seat
models equipped with load legs, there was some interaction between the
load leg and the mounting hardware on the sled ``floor'' as well as
front camera hardware. CU suggested that elimination of hardware or
test components in the area directly ahead of the test bench may be
warranted in updates or final rule changes to limit possible
interaction with the load leg of rear-facing seats.
In response, load legs cannot be used in the side impact
configuration as the sliding seat is on rails connected to the base
plate/floor. The floor does not move during the test as the seat
assembly slides along the rails. Further, NHTSA will not use load legs
in the FMVSS No. 213a compliance test. Under FMVSS No. 213a, a top
tether will be attached (in forward-facing CRSs that provide one), but
supplementary devices will not be used.\161\ If manufacturers want this
option for testing CRSs for purposes other than compliance testing,
they can design a SISA with a floor that can be used for supporting
load legs. MGA suggested that NHTSA define the overall length of the
equipment (base plate, rails, rail mounting plate) as a reference
dimension. MGA stated that depending on the sled system, equipment, and
input used, more or less ramp up room may be required to perform the
test. MGA also stated that allowing additional length would provide the
opportunity to test to more severe inputs. NHTSA declines to make this
change. If manufacturers want to test at different settings, they can
vary the rail length as convenient in their system.\162\
---------------------------------------------------------------------------
\161\ This is consistent with the requirements of FMVSS No. 213.
Load legs are not permitted to meet the minimum threshold
requirements of FMVSS Nos. 213 and 213a because the agency is
concerned that caregivers will not use the load leg. Manufacturers
may provide a load leg to supplement performance beyond the
threshold needed to meet the FMVSSs, but the CRS must meet the
requirements of the FMVSSs without use of the load leg.
\162\ As discussed below, NHTSA's drawing package contains
drawings that are appropriate for an acceleration-type test. NHTSA
did test on a deceleration-type sled in the Kettering study that
used longer rails, because the deceleration-type sled needs a longer
distance to ramp up to the desired speed.
---------------------------------------------------------------------------
Regarding the bench seat panel assembly, MGA commented that the
attachment method for holding the ``Bench Seat Panel'' and ``Bench Seat
Back Panel'' (Drawings 2921-360 and 2921-380) to the ``Bench Seat
Assembly'' (Drawing 2921-310) were not durable enough. MGA said that
the attachment bolts thread into thin steel and stripped out very
quickly, and that MGA accordingly replaced most of these fasteners with
thru-bolts. MGA suggested thicker wall tubing, a captured nut, or other
means for attaching to the bench (seat assembly). Updates to the seat
assembly design make MGA's suggestions to drawings 2921-360 and 2921-
380 moot as drawings 2921-360 and 2921-380 drawings were removed. Also,
the seat back and seat pan design were changed in the updated 2921-310
drawings, making MGA suggestions no longer relevant.
Regarding the tether anchor mount, MGA commented that Drawing 2921-
340, ``Top Tether Anchor,'' has a single mounting bolt to attach the
mount to the seat frame, which allows the tether anchor to rotate
during testing. MGA suggested that it may be desirable to mount the
tether anchor with a second bolt to prevent this pivot motion. NHTSA
agrees and has modified the tether anchor design to prevent rotation
and so it can be replaceable in case of bending during testing. The new
tether anchor design consists of an easily replaceable bolt that goes
through two small wings attached to the seat assembly, with two bolts
to prevent rotation. The replaceable bolt serves as the tether anchor
in the new design.
Regarding Drawings 2921-370 and 2921-390 ``Bottom Seat Cushion
Ass'y'' and ``Seat Back Cushion Ass'y,'' MGA stated these drawings are
inconsistent on the width of the seating surface. The bottom cushion
specifies a width of 695 mm (27.4 inches) while the back cushion
specifies a width of 670 mm (26.4 inches). In response, NHTSA updated
drawings 2921-370 ``Seat Pan Cushion Ass'y'' and 2921-390 ``Seat Back
Cushion Ass'y'' and they are now the same dimensions 711 mm (28 inches)
width.
Regarding Drawing 2921-321 ``Bench Top Anchor Brace Plate,'' MGA
commented that it believed this drawing is obsolete. NHTSA agrees and
the brace plate has been eliminated from the drawings.
Regarding Drawing 2921-100 ``Base Plate,'' MGA had four
suggestions. First, change the M10 tapped holes for rail base plate
mounting to M12. The through holes in rail mount plate (Drawing 2921-
251) and end stop ``Bumper Base'' and ``Bumper Base Extension''
(Drawings 2921-411 and 2921-412) are 0.531 inches and 0.500 inches
which are too big for an M10 bolt.
Second, allow the option to use aluminum to reduce the weight of
the setup. Third, remove thru holes for attaching to the VRTC sled; and
fourth, make the overall rail length for reference only to allow
changes for different sled facilities. In response, NHTSA switched the
holes to M12; allowed the option to use aluminum to reduce the weight
of the setup; and removed all extra thru holes. In regards to the last
suggestion, the drawing package contains drawings for an acceleration-
type sled test. If manufacturers want to test at different settings or
use different types of sled systems, they can vary the rail length as
needed. The Kettering study \163\ of a deceleration-type sled used
longer rails than the drawings as the deceleration sled needs a longer
distance to ramp up to the desired speed.
---------------------------------------------------------------------------
\163\ Brelin-Fornarni, J., ``Development of NHTSA's Side Impact
Test Procedure for Child Restraint Systems Using a Deceleration
Sled: Final Report, Part 1. April 2014. Link: https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/811994-sideimpcttest-chrestraintdecelsled_pt1.pdf.
---------------------------------------------------------------------------
MGA stated Assembly 2921-210 ``Impactor Stop Assembly,'' can be
changed from referencing two bolt together weldments to a single
weldment by changing (1) Assembly 2921-220 ``Impactor Stop Frame
[[Page 39269]]
Assembly'' to remove holes in the plate for Drawing 2921-221 and
eliminating items 2921-224, 2921-225, 2921-226; and (2) Assembly 2921-
230, ``Honeycomb Frame Assembly,'' by eliminating item 2921-231,
extending item 2921-232 by 0.25 inches and extending item 2921-235 by 6
inches. In response, NHTSA removed the holes in plate for part 2921-
221. Drawings 2921-(225-226) were removed. Drawing 2921-224 was not
removed as it is referenced in the drawing package. Item 2921-231 was
removed. The dimension was increased by 0.28 inches (rather than 0.25
inches as suggested) to correctly depict the length in drawing 2921-232
(from 136.5 mm or 5.38 inches to 143.7 mm or 5.66 inches). The
dimension was extended in drawing 2921-235 by 6 inches, as suggested.
Regarding Drawing 2921-241-1 ``Impactor Frame Tube 1,'' MGA
suggesting changing the length of the frame tube from 30.80 inches to
29.50 inches to match the height of the impactor frame and to match
part 2921-241-2. In response, NHTSA changed the length of the impactor
frame tubes, to depict the correct length of 29.50 inches, as
suggested. Drawing 2921-241-1 has been removed and replaced by -241-2.
Regarding Drawing 2921-251 ``Rail Mtg. Plate,'' MGA suggesting
changing the width from 5.91 inches to 6 inches, as a 6-inch plate is
commonly available, and the change reduces machining processes. In
response, NHTSA changed the width of the plate to 6 inches.
Regarding Assembly 2921-311-9 ``Bench Frame Tube #9 Assy.,'' MGA
suggested removing notches and extra pieces as these were believed to
be obsolete. NHTSA has removed Assembly 2921-311-9, so this suggestion
is no longer applicable.
Regarding Drawing 2921-313 ``Bench Bearing Support Plate,'' MGA had
three suggestions: change overall length from 24.41 inches to 24.56
inches, as the current length does not fit the size of the SISA; change
the width from 4.016 inches to 4.00 inches, as four-inch plates are
readily available; and change slots to holes, if the purpose of slots
is unnecessary. NHTSA agrees and has made these suggested changes.
Regarding Drawing 2921-314 ``Bench Frame Center Stiffener Plate,''
MGA commented that this plate appeared to be obsolete, and recommended
removal of the drawing. NHTSA did not remove the plate from the drawing
package, because the plate is still in use. The stiffener plate helps
overall buck durability.
Regarding Drawing 2921-322 ``Bench Stop Plate,'' MGA suggested
changing the plate with from 5.91 inches to 6 inches, as six-inch
plates are readily available. MGA also questioned the purpose of holes
in the plate, and requested the agency remove the holes if they were
obsolete. In response, NHTSA changed the dimension of the plate in the
drawing as suggested. The holes in the plate are necessary, as holes
need to be present for the honeycomb to provide the correct response
(air flow through the honeycomb) for correct deceleration.
Regarding Drawing 2921-331 ``Light Trap Vane,'' MGA suggested
removing the drawing from the package, as depending on the model of
light trap used to measure velocity, different sized vanes or flags may
be necessary. NHTSA agrees, and the drawing has been removed.
Regarding Drawings 2921-372 ``Seat Bottom Cushion'' and 2921-392
``Seat Back Cushion,'' MGA had three comments: first, MGA noted that
the cutouts to allow clearance for the belt anchors were not the same
size for the left and right side, and asked if this was intentional (as
drawings 2921-371-1 ``Seat Bottom Cushion Mtg. Plate'' and 2921-360
``Bench Seat Panel'' have the same size cutouts for the left and right
side). Next, MGA stated the location of the cutouts does not match the
location on Drawing 2921-371-1 ``Seat Bottom Cushion Mtg. Plate'' and
the misalignment can be seen in assembly 2921-370 ``Seat Bottom Cushion
Assy.'' Finally, MGA stated that the specified material has proven
difficult, if not impossible to obtain. MGA suggested NHTSA specify a
more commonly available polyurethane foam block with a specified
density and force/deflection. In response, as discussed above, NHTSA
modified the SISA so that the final foam design does not have cutouts.
In addition, as discussed above, NHTSA has identified several
manufacturers that could produce the specified foam. This is discussed
in more detail in the Foam Feasibility Study included in the docket
with this final rule.\164\
---------------------------------------------------------------------------
\164\ ``Foam Feasibility Study by National Center for
Manufacturing Sciences'' (NHTSA, June 2018). This document is in the
docket for this final rule.
---------------------------------------------------------------------------
Regarding Drawings 2921-373 ``Bottom Seat Cushion Cover'' and 2921-
393 ``Seat Back Cushion Cover,'' MGA suggested NHTSA specify a more
commonly available material such as ``cotton duck,'' which can be
purchased from a variety of vendors. MGA also suggested NHTSA specify a
detailed method of wrapping and attaching the cover material. In
response, NHTSA added details for the cover material to the drawing
package. The current wrapping method is specified in the report,
``FMVSS No. 213 Side Impact Test Evaluation and Revision'' \165\ and
will be available in the compliance test procedure (TP) placed on
NHTSA's website.
---------------------------------------------------------------------------
\165\ Louden & Wietholter (2022).
---------------------------------------------------------------------------
Regarding Drawing 2921-391-1 ``Seat Back Cushion Mtg. Plate,'' MGA
suggested reducing the thru hole size from 0.328 inches to 0.281 inches
for specified 1/4-28 hardware. In response, NHTSA found the suggested
0.281 inch through hole was too small to slide down the bolts and lay
flush with the seat back pan. Accordingly, the dimension was changed to
0.34 inch, which corresponds to a 11/32 standard bit size.
Regarding Drawing 2921-396 ``Rail Bearing Mount Plate,'' MGA
suggested changing the overall length from 30.98 inches to 31 inches as
it currently does not match Drawing 2921-397, ``Anti-Rebound Slider
Base,'' which attaches to it. MGA also suggested changing the thickness
from 0.35 inch to 0.375 inch (\3/8\ inch), as a \3/8\ inch plate is
referenced as the material, and reducing the thickness to 0.35 inch
through a machining process is very time consuming and costly. In
response, NHTSA changed the overall length dimension to 31 inches as
suggested, and the thickness was updated to \3/8\ inch in the drawing
package.
Regarding Drawing 2921-404, ``Anti-Rebound Fixture Stop Plate,''
MGA stated that, currently, the plate has a taper and is not a constant
thickness, and questioned whether this was intentional or a drawing
error. MGA stated that if this is an error, it should be corrected to a
constant 0.75 inch thickness. MGA also stated that the Countersink is
currently drawn for \1/2\ inch hardware, but \5/8\ inch hardware is
specified in drawing 2921-400, ``Anti-Rebound Fixture Ass'y.'' In
response, NHTSA changed the hanged plate thickness to a constant 0.75
inch, as suggested. The drawings were also changed to have a \5/8\ inch
countersink.
Regarding Drawing 2921-411 ``Bumper Base,'' MGA stated that the
thru holes for attaching to the base plate are not dimensioned in the
drawings, and should be to make the drawing fully defined. In response,
NHTSA added dimensions so that the drawing is fully defined.
Regarding Drawing 2921-501 ``Impactor Door Foam,'' MGA had three
comments: first, the thickness is drawn to 2.2 inches but in the
proposed regulatory text a thickness of 2 inches is referenced; second,
the drawing is not fully constrained, as the two angles are
[[Page 39270]]
not dimensioned; and third, that the geometry does not match the
geometry of Drawing 2921-243, ``Impactor Door Plate,'' to which this
piece attaches. In response, NHTSA changed the thickness of the door
foam to 2N (Nominal) and dimensions were added to be fully constrained.
NHTSA also changed the drawing so that the geometries of the door plate
and door foam match.
Regarding Drawing 2921-600 ``Honeycomb,'' MGA suggested removing
the overall dimensions from the drawing and making it for reference
only. MGA stated that different pieces of equipment may behave
differently and need to be tuned through the sizing of the honeycomb
material. MGA also suggested that NHTSA specify if the honeycomb is to
be ``pre-crushed'' as is common with testing involving aluminum
honeycomb. In response, NHTSA did not make any changes to the drawing,
as honeycomb is in the optional section of the drawings so that test
facilities can use the honeycomb material and cut it to different sizes
if necessary. NHTSA did not indicate pre-crush, as discussed above.
Regarding Assembly 2921-700 ``Light Trap Assembly,'' MGA suggested
removing drawings 2921-700, 2921-701, 2921-702. MGA stated that
depending on the model of the light trap being used to record velocity,
different sized and shaped attachments may be necessary. In response,
NHTSA removed Drawings 2921-(700-702). The test procedure will not be
using a light trap to determine closing speed, and therefore the
drawings are not needed.
5. Other Testing Issues
i. Right-Side Impacts
MGA also commented that there is no ability to perform FMVSS No.
213a testing on the right side of the CRS. MGA stated that wording in
the proposed rule dictates the need to perform left- and right-side
impacts but the SISA drawing package is not reversible and cannot be
used for right-side impacts. MGA recognized modifying the equipment
would require significant redesign.
MGA is correct that the SISA can only test left-side impacts. A
SISA that would allow both impact directions would have to be designed,
and such redesign would likely affect the overall weight of the sliding
seat, and, therefore, the specifications for the rest of the settings
(i.e., honeycomb, input acceleration and velocity). Another option
would be to specify a mirror-image SISA to test in a right-side impact
configuration, but developing such a sled assembly would also take time
and resources and involve doubled testing costs. NHTSA has decided that
both approaches are unnecessary at this juncture. While the standard
only specifies a test simulating a left-side impact, as a practical
matter it is reasonable to conclude that manufacturers will apply to
the right side the same countermeasures that protect against left side
impacts. Because of market forces (consumers will likely prefer CRSs
that provide both left- and right-side protection over ones that
provide only left-side protection), manufacturer diligence, liability
concerns and the practicability of countermeasure design, NHTSA
believes manufacturers will be motivated to apply the countermeasures
developed for the left side to both sides of the CRS. The agency also
plans to query CRS manufacturers to see if they have designed their
CRSs so that the child restraints perform equally in a right-side
impact as they do in the left-side test to keep informed of industry
practices in this area.
ii. Sliding Seat Bearings
JPMA commented that several smaller JPMA members were concerned
with the cost of the sliding seat bearings for the FMVSS No. 213a test
set-up. JPMA explained that based on observations during side impact
testing, such bearings will only last 30 to 40 runs per set and cost
$750 to replace. JPMA added that the bearings wear quickly in the
proposed side impact test due to lateral load imposed by the difference
in the travel angle of the sled and the sliding seat and the lateral
and vertical loads during the impact. JPMA explained that as the
bearings wear down, they create drag, which will eventually cause the
sliding seat pulse to exceed specifications. JPMA added that during the
wearing process, additional burden on the already impaired bearings
causes them to wear out even faster, and thereby necessitating frequent
replacement.
JPMA suggested that one possible solution would be to adjust the
drawing package, which specifies that flange bearings be used. JPMA
stated its belief that the deletion of that requirement would allow
each test facility and/or manufacturer the opportunity to determine
what type of bearings work best with their test fixtures.
NHTSA concurs with the suggestion. The drawings are modified to
specify the bearings as ``THK Linear Motion Guide Model HSR30-B-2-UU-
M+1315-M-II or equivalent'' to allow compliance test facilities to use
different brand of bearings. VRTC measured the drag pull/push force
during testing to evaluate whether the bearings were causing excessive
friction as they were wearing down (excessive friction is an indication
that they may need replacement.).\166\ The data indicated that the drag
force did not increase appreciably as the bearings were wearing down,
and VRTC only replaced the bearings if, after higher than normal push/
pull forces were observed, the push/pull forces did not decrease after
greasing the bearings, or after additional troubleshooting. Per this
methodology, VRTC replaced the bearings after approximately every 80
tests. NHTSA believes replacing the bearings every 80 to 100 tests is
not an unreasonable cost burden. Further, NHTSA estimates the cost of a
bearing set is $440 ($110 each), which is less than what JPMA
estimated.
---------------------------------------------------------------------------
\166\ See Louden & Wietholter (2022) for documentation on drag
pull/push force which may predict if bearings have high friction.
The increase in pull/push force may also be attributed to other
causes explained in the report.
---------------------------------------------------------------------------
iii. Seat Belt Interference
Graco commented that, during the time of engagement between the
aluminum honeycomb and the impact surface of the sliding seat, the Type
2 shoulder belt is engaged with the door structure, which can result in
a different acceleration pulse.
As discussed further in the section on Repeatability and
Reproducibility below, NHTSA's testing with the CRS installed using the
Type 2 (lap/shoulder belt) showed no interference of the shoulder
portion of the Type 2 belt with the door.\167\ In testing, the shoulder
portion of the Type 2 belt slides behind the door during contact of the
sliding seat with the door. This interaction did not affect the sliding
seat acceleration pulse or any of the performance measures.
---------------------------------------------------------------------------
\167\ Figures illustrating the Type 2 seat belt testing showing
no interference with the door are docketed with this final rule.
---------------------------------------------------------------------------
c. Sled Kinematic Parameters
1. General
In designing FMVSS No. 213a, NHTSA examined data from FMVSS No. 214
MDB compliance tests to identify kinematic characteristics of a side
impact crash, so that the sled test would be representative of the
crash experience of a child restrained in a CRS in the rear seat. NHTSA
identified the following sled kinematic parameters to replicate in the
FMVSS No. 213a test: (1) the acceleration profile of the sliding seat
(representing the struck vehicle acceleration); (2) the door velocity
at time of contact with the sliding seat (this represents the struck
vehicle door
[[Page 39271]]
velocity); and (3) the impact angle of the door with the sliding seat
(to replicate the longitudinal component of the direction of force).
NHTSA determined that a small passenger vehicle in an FMVSS No. 214
MDB crash test experiences a lateral change in velocity of about 30 km/
h (18.6 mph). This change in velocity is greater than 92 percent of
near-side impact real-world crashes involving restrained children 0- to
12-years-old in light vehicles, as estimated by NHTSA using data files
from the National Automotive Sampling System Crashworthiness Data
System (NASS-CDS) (now known as the Crash Investigation Sampling
System). To ensure that the side impact test would be sufficiently
stringent to account for the greater acceleration and intrusion
experienced by smaller vehicles, the agency focused on the crash
characteristics of small passenger vehicles in FMVSS No. 214 side MDB
tests, as opposed to the average estimates from all vehicles.
As discussed further below, NHTSA proposed a test procedure that
specified the following parameters:
A trapezoidal sliding seat acceleration profile
(representing the struck vehicle acceleration) based on an analysis of
ten small vehicle FMVSS No. 214 tests.
A sled buck impact angle of 10 degrees. NHTSA selected
this impact angle based on two factors: (1) the same small vehicle
FMVSS No. 214 MDB tests; and (2) a series of tests within a range of 0
to 20 degrees (at 0, 10, 15, and 20 degrees) to evaluate the effect of
the test buck's impact angle on dummy kinematics and injury responses.
Separate tests conducted to compare the Takata-based test to four MDB
crash tests also found that a 10-degree impact angle on the sled test
produced dummy responses closer to those measured by the ATD in the
same CRS in the four MDB crash tests than the other impact angles.\168\
---------------------------------------------------------------------------
\168\ Sullivan et al. (2009).
---------------------------------------------------------------------------
A door velocity (representing the struck vehicle door
velocity) of 31 km/h (19.3 mph) prior to the honeycomb contacting the
sliding seat structure, based on the FMVSS No. 214 tests of small
vehicles with accelerometers installed on the doors (four out of the
ten tested vehicles).
NHTSA sought comment on a relative door velocity profile. The
agency sought to avoid over-specifying the test environment, but stated
that a door velocity profile, with respect to the sliding seat, may be
desirable to improve the reproducibility of the interaction of the
intruding door with the child restraint in different types of sled
systems. Accordingly, NHTSA sought comment on the need for specifying a
relative door velocity profile to improve reproducibility of the test
procedure. NHTSA stated that, depending on whether the agency received
information sufficiently supporting such a velocity profile, one could
be included in the final rule.
Comments Received (High View)
There was overarching support for the proposed sled test procedure.
Mr. Hauschild agreed that the NHTSA test procedure should account for
the struck side door velocity, including the struck vehicle
acceleration profile, and the impact angle to replicate a side impact
crash. He also stated that testing should be done with and without the
intruding door due to the complexities of the side impact crash event.
Dorel commented in agreement with the test procedure's intruding door
approach, stating that it does not support a test procedure that does
not incorporate an intruding door. Dorel concluded that there is no
reason to develop, or require a fixed door procedure that has been
shown to be unrepresentative of injury mechanisms like intrusion.
As part of its response to NHTSA's request for comment regarding
the need to specify a relative velocity profile, Graco requested NHTSA
provide data demonstrating that a CRS tested on both a deceleration and
acceleration sled would provide the same end results given that the
test meets the currently defined constraints. Similarly, Mr. Hauschild
commented that the vehicle pulse must be incorporated into both an
acceleration and deceleration sled test procedure, as it will influence
the ATD kinematics.
ARCCA recommended that side impact testing of the CRS also be
conducted at a severity level comparable to side-NCAP vehicle crash
testing. ARRCA stated its belief that the higher severity testing would
be consistent with crash severity levels currently used to ensure that
adult occupants are optimally protected.
Agency Response
The final test's procedure specifications are in large part the
same as that proposed in the NPRM, with some refinements. In response
to the questions posed by NHTSA in the NPRM, and as discussed in more
detail below, many commenters supported including a relative door
velocity profile in the final test procedure. NHTSA concurs and has
included the profile into the final test procedure. As discussed
further in a section below, NHTSA's testing at Kettering University
after issuance of the NPRM using a deceleration-type sled showed good
coefficient of variation (CV) values. The reproducible results from
VRTC and Kettering confirm that the side impact test can be performed
in the different sled systems and produce the same results.
NHTSA disagrees with ARCCA's comment that CRS side impact testing
be conducted at a severity level comparable to side-NCAP vehicle crash
testing. The FMVSS No. 214 MBD impact test speed of 53.9 km/h (33.4
mph) accounts for approximately 92 percent of near-side crashes
involving restrained children (0- to 12-years-old children in all
restraint environments--seat belts and CRSs). The NCAP side impact MDB
test is performed at an impact speed of 61.9 km/h (38.4 mph), which is
8 km/h (4.9 mph) greater than the speed required in FMVSS No. 214.
The side impact performance requirements set by the FMVSS \169\ are
established at a threshold level of performance that meets the need for
motor vehicle safety and that satisfies the other requirements for
setting FMVSSs established by the Safety Act. NCAP's side impact
performance tests are set at a higher speed to provide comparative
information consumers can use to shop for vehicles, and to incentivize
vehicle manufacturers to attain higher levels of performance beyond the
minimum set by the FMVSS. In order to estimate the effectiveness of CRS
padding to mitigate fatalities in side crashes, NHTSA conducted an in-
depth investigation of all cases in the NASS/CDS and Special Crash
Investigation (SCI) data files for the 8-year period from 2002 to 2009
where a vehicle impacted on its side in a crash had a CRS restrained
child occupant who was killed in the crash.\170\ Results showed that
for near side impacts, most fatalities (14 out of 17) were not
survivable due to extensive vehicle damage and intrusion (which
indicated increased severity/speed) or gross misuse. The agency
determined that additional padding and improved CRS designs would not
have prevented the 14 child occupant fatalities. Therefore, NHTSA does
not believe that increasing
[[Page 39272]]
the test speed above the FMVSS No. 214 MDB impact speed will provide
additional safety benefits that merit the change. In making regulatory
decisions on possible enhancements to CRS performance, NHTSA bears in
mind consumer acceptance of cost increases to child seats, a highly
effective item of safety equipment. Countermeasures employed to meet
requirements beyond those necessary to meet a safety need may result in
additional costs that could reduce CRS sales and CRS use. For these
reasons, NHTSA declined to raise the test speed of FMVSS No. 213a to
match that of side-NCAP tests.\171\
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\169\ Per the National Traffic and Motor Vehicle Safety Act,
``motor vehicle safety standards'' means a minimum standard for
motor vehicle performance, or motor vehicle equipment performance,
which is practicable, which meets the need for motor vehicle safety
and which provides objective criteria.
\170\ Preliminary Regulatory Impact Analysis--Side Impact Test
for Child Restraints FMVSS No. 213, January 2014. Docket No. NHTSA-
2014-0012-0007.
\171\ The severity of the FMVSS No. 213a test protocol is
greater than the existing side impact test in ECE R.129.
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2. Specific Issues
The following sections discuss additional comments received on
aspects of the test procedure related to the sled kinematic parameters,
including the sliding seat acceleration profile, the door impact
velocity and relative velocity and impact time, and the longitudinal
crash component, and the agency's response to those comments.
i. Sliding Seat Acceleration Profile
To obtain a target acceleration profile for the sliding seat that
represented the motion of a struck vehicle, NHTSA analyzed the right
rear sill (the opposite side of impact) lateral (Y-axis) acceleration
of ten small vehicles in FMVSS No. 214 tests.\172\ The results showed a
change in velocity of approximately 26 to 29 km/h (16 to 18 mph). The
right rear sill accelerations were averaged to derive a typical struck
vehicle acceleration corridor for small-sized vehicles.
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\172\ Sullivan et al. (2009).
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Figure 6 shows the upper and lower boundaries of the rear sill
accelerations in thick solid black lines while the dotted line
represents the average of the accelerations. The solid thin black line
in Figure 6 is a representative sliding seat acceleration pulse.
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[[Page 39273]]
Accordingly, in the NPRM, NHTSA defined the acceleration corridor
for the sliding seat as shown in Figure 7:
[GRAPHIC] [TIFF OMITTED] TR30JN22.010
Mr. Hauschild argued that the proposed trapezoidal pulse for the
overall crash pulse is not representative of real-world crashes of
current smaller and medium-sized vehicles, stating that a side impact
event in small- and medium-sized vehicles can be harder to protect
against than in larger vehicles. He stated that during the crash event
of small- and medium-sized vehicles, typically there is a sharp
acceleration in the first 10-15 milliseconds ending with the
trapezoidal shape for the remaining 45-50 milliseconds, and that the
acceleration pulse shape will influence dummy head excursion and
displacement. Mr. Hauschild recommended that NHTSA examine the
influence of vehicle pulse shape on dummy kinematics.
NHTSA concurs that smaller vehicles experience a side impact
differently than larger vehicles but disagrees that the proposed
corridor for the pulse is not representative of the real-world crash of
smaller and medium-sized vehicles. NHTSA explained in the NPRM that the
proposed acceleration corridor was based on the vehicle accelerations
of small passenger vehicles in the FMVSS No. 214 MDB side impact tests
and therefore represents the more challenging side crash environment of
small vehicles. Comparing the accelerations of the 10 small vehicles,
Figure 8 shows that in the initial 10 milliseconds, the proposed
corridor allows for a sharp acceleration, as described by Mr.
Hauschild. In addition, the proposed FMVSS No. 213a sliding seat
acceleration pulse follows that initial sharp acceleration in a similar
manner as the vehicle acceleration pulses in these small-vehicle FMVSS
No. 214 side impact tests. This is also consistent with the sharp
acceleration in the first 10-15 milliseconds, followed by a trapezoidal
shape for the remaining 45-50 milliseconds as described by Mr.
Hauschild. While the trapezoidal acceleration corridor is necessary to
allow for the oscillations that will be present during the side impact
test, the corridor must be limited, as a wider corridor that would
encompass the lower bound of all vehicle curves could also increase the
variability of testing and make reproducibility more difficult. As
shown in the figure below, the acceleration corridor is representative
of the accelerations experienced in a side impact of a small vehicle.
Accordingly, this final rule adopts the acceleration boundaries as
proposed.
[[Page 39274]]
[GRAPHIC] [TIFF OMITTED] TR30JN22.011
ii. Tuning the Test To Account for Lighter Dummies
JPMA commented that, when testing CRSs using lighter weight dummies
like the 12-month-old CRABI, Calspan (an independent testing facility)
has added weight to the sliding seat to maintain the pulse in the
corridor specified by the NPRM. JPMA argued that the addition of this
weight was not mentioned in the NPRM, and that such a practice could
impact results and introduce variation if only some test facilities
were doing it. JPMA suggested that NHTSA consider addressing how to
maintain a pulse within the corridor when testing with lighter weight
dummies like the 12-month-old CRABI.
In response, NHTSA has tested CRSs at two different test
facilities: VRTC, using an acceleration-type sled and Kettering
University, in a deceleration-type sled. In both test facilities, the
variation in weight of the CRS and the dummy has had no significant
effect on the pulse. However, when Kettering University tested lower-
weight infant carriers with the 12-month-old CRABI dummy, it had to add
weight to the sled system (not the sliding seat) because the impact
speed increased, making the corridor and impact speed slightly higher
than the FMVSS No. 213a test specifications.\173\ These sensitivities
will have to be tuned at each test facility, as each facility will have
to provide the correct input that results in the required velocity and
accelerations of the sled buck and the sliding seat. The inputs are not
consequential to test outcomes, as long as the required velocities and
accelerations are attained for the test. Thus, the agency has decided
that no change to FMVSS No. 213a is necessary.
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\173\ More details on how and when Kettering adjusted its sled
system weight can be found in the technical report: Brelin-Fornari,
J., ``Final Report on CRS Side Impact Study of Repeatability and
Reproducibility using a Deceleration Sled,'' July 2017.
---------------------------------------------------------------------------
iii. Acceleration Corridor
MGA suggested several modifications to the proposed sliding seat
acceleration corridor. First, MGA suggested that the corridor be
widened at time T0 (time when the siding seat first contacts
the door assembly), to a 3G maximum. MGA stated that the sliding seat
will have some acceleration at time of contact, making it difficult for
the acceleration profile to fit into the very narrow acceleration range
of the corridor at time T0. Next, MGA suggested the agency
change the slope of the lower boundary of the corridor from time
T0 to time 15 msec after T0 to match the slope of
the upper boundary of the corridor to further widen the corridor. MGA
stated that the rise time of the test is dictated by the honeycomb,
which has a very sharp rise rate that does not match that of the lower
boundary of the corridor. Separately, MGA stated that further
specification needs to be provided on the measurement of the sled and
sliding seat acceleration and velocities. MGA used points (time versus
G level) on the corridor for the acceleration of the sliding seat as an
example of such additional data.
Agency Response
Regarding MGA's first suggestion to increase the acceleration upper
boundary at time T0 to 3 Gs, NHTSA's testing at VRTC and
testing at Kettering obtained sliding seat accelerations that fell
within the proposed acceleration corridor at time T0. The
sliding seat had some movement prior to impact with the honeycomb,
however, that movement is minimal and results in negligible
acceleration of the sliding seat. Additionally, MGA's comments during
the second comment period showed that it was able to meet the proposed
sliding seat acceleration corridor at time T0.\174\
Additional test data provided by Graco in support of its comments to
the NPRM also indicated that the initial acceleration of its sliding
seat was within the proposed sliding seat acceleration corridor.
Therefore, data indicate MGA's concern regarding the narrow initial
acceleration corridor of the sliding seat is no longer an issue, and so
the agency has made no change to the proposed sliding seat acceleration
corridor at and near time T0.
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\174\ NHTSA-2014-0012-0043, at pg. 2 (Figure 1).
---------------------------------------------------------------------------
MGA also suggested making the first leg of the lower acceleration
corridor wider. NHTSA believes that this also may no longer be an
issue, as data provided by MGA and Graco show that the test facilities
could meet the sliding seat acceleration corridor. NHTSA
[[Page 39275]]
believes it must balance the capability of test facilities to meet the
acceleration corridor with maintaining good repeatability of the test.
For these reasons, NHTSA is not modifying the lower boundary of the
acceleration corridor between time T0 and 15 msec after
T0, as suggested by MGA. In response to MGA's comment that
further clarification needs to be provided on the measurement of the
sled and sliding seat acceleration and velocities, the agency has
included the sliding seat acceleration corridor coordinates in this
final rule's regulatory text.
After consideration of these comments, NHTSA is maintaining the
sliding seat acceleration profile proposed in the NPRM for the final
test procedure. This acceleration profile appropriately represents the
accelerations experienced in a side impact of a small vehicle.
3. Door Parameters
The door velocity (which represents the struck vehicle door
velocity) was obtained from the integration of door acceleration data
from four of the ten aforementioned FMVSS No. 214 compliance tests
(these four vehicles were the only ones tested with accelerometers
installed on the door). The accelerometers were installed in the inner
structure of the door at the upper centerline and mid centerline door
locations. The resulting lateral (Y-axis) peak velocities of the door
during interaction with the test dummy ranged from 30 km/h (18.6 mph)
at the upper centerline to 32.0 km/h (20 mph) at the mid-centerline.
Thus, the target lateral door velocity selected for the test buck was
31 km/h (19.3 mph), the average of the velocities, prior to the
honeycomb contacting the sliding seat structure.
NHTSA explained in the NPRM that, since the kinematics of the door
prior to the interaction with the sliding seat do not affect the energy
and impulse imparted to the sliding seat and child restraint system,
the agency believed that the acceleration profile of the impacting door
did not need to be specified as long as its velocity during the
interaction with the sliding seat and child restraint system is
maintained within specified velocity tolerances.
Response to Comments
Dorel and JPMA requested clarification of data and information
contained in Figure 25 of the ``Child Restraint Side Impact Test
Procedure Development'' technical report (velocity data plots from
vehicle test 6635 and sled test 6904).\175\ Dorel noted the peak
velocity of the sliding seat appeared to be 27 km/h (16.7 mph). While
the door velocity has a 34 km/h (21.13 mph) at T0 and a 30.5
km/h (18.95 mph) door velocity at 50 ms, Dorel argued that this did not
appear to be consistent with the specifications of the NPRM to: (1)
accelerate the test platform to achieve a relative velocity
(V0) of 31.3 0.8 km/h in the direction
perpendicular to the SORL between the SISA sliding seat and the door
assembly at the time they come in contact (time = T0); and
(2) ensure the sliding seat has a change in velocity of 31.3 0.8 km/h and an acceleration within the proposed corridor.
---------------------------------------------------------------------------
\175\ Sullivan et al. (2013).
---------------------------------------------------------------------------
Agency Response
The purpose of Figure 25 of the technical report was to illustrate
that the event of the side impact sled test is very similar to the
FMVSS No. 214 vehicle side impact crash. Test 6635 was one of the 4
vehicle tests that helped determine the door velocity. Because the
vehicle inner door velocities are only measured in two points in the
door and the initial door velocities are not stable as shown by the
wide oscillations in the beginning of the event, the door velocity was
taken once the door velocity signal was stabilized, which was between
30 km/h (18.6 mph) and 32.0 km/h (20 mph). These velocities were within
the ranges specified in the NPRM. When the door interacts with the
seat, the seat starts to move along with the door, and so the velocity
of the seat is the same as that of the door. In the side impact sled
test, the sliding seat interacts with the door and moves along with the
door after crushing of the honeycomb structure. As shown in Figure 25
of the referenced technical report, the simulated door and sliding seat
velocity of the sled test configuration is most similar to that of the
Nissan Sentra.
Graco and MGA commented that they were unable to keep the door
velocity at less than or equal to the initial door velocity
(V0) and greater than or equal to V0-1 km/h
during the interaction with the sliding seat. Graco presented a
velocity pulse comparison from three different test labs, stating that,
while it appeared that the velocity requirements and acceleration
corridor were achievable on a consistent basis, their testing indicated
that all three test facilities were not able to meet the requirement
for the door structure velocity to stay within 1 km/h during contact
with the sliding seat.\176\ Graco surmised that the variation drivers
between the three facilities were most likely the aluminum honeycomb
area, differences in accelerometer types and locations, and differences
in pressure settings. Graco suggested that the countermeasures to
improve the consistency of aluminum honeycomb geometry may improve this
inconsistent velocity. Graco compared velocity results to the actual
proposed limits to understand if the targets were achievable and
commented that the limits appeared to be achievable, but controls are
needed to prevent the sliding door velocity from falling more than
V(T0)-1 during the door contact event.
---------------------------------------------------------------------------
\176\ NHTSA-2014-0012-0042, at pg. 5. Graco stated that crash
test facilities 1 and 3 had the door structure relative velocity
drop more than 1 km/h [0.62 mph] and that crash test facility 2 did
not meet the target velocity of 19.45 mph at T0 and also
demonstrated increased velocity during the time of contact with the
sliding seat.
---------------------------------------------------------------------------
NHTSA agrees with Graco that the honeycomb area and volume are
important to control the sliding seat acceleration. This final rule's
SISA specification includes details on the honeycomb material and its
dimensions to improve reproducibility of the test results. However, we
clarify to readers that the honeycomb area and/or volume can be
modified, as necessary, to tune each system to obtain a sliding seat
acceleration within the specified acceleration corridor; the regulatory
text does not provide express specifications on this aspect of the
procedure.
NHTSA agrees that the accelerometer type and location are important
to achieve consistent results in different test facilities.
Accordingly, the accelerometer type and location have been specified in
the final SISA technical drawings.
Graco also requested that NHTSA provide more background
information, including NHTSA's experimental data, regarding the need to
control the relative velocity within 1 km/h while the door structure is
in contact with the sliding seat. Graco suggested that if this is not a
critical parameter, NHTSA should consider increasing the 1 km/h limit
because test facilities did not meet the proposed specification.
Similarly, MGA stated that it successfully met the sled test
specifications but was unable to meet the requirement that the door
velocity not decrease more than 1 km/h during the interaction with the
sliding seat. MGA explained that during the time of interaction (which
MGA assumed to mean the duration of the honeycomb crush--roughly 50 ms
to 100 ms), MGA observed a velocity change from around 32 km/h to
around 29 km/h (a 3 km/h change), and noted that the velocity change at
VRTC was
[[Page 39276]]
from 32 km/h to around 30 km/h (a 2 km/h velocity change).\177\ MGA
stated that the velocity change during the impact in both the test
facilities would be considered to be outside the limit proposed by the
NPRM, and suggested that this test specification be modified.
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\177\ NHTSA-2014-0012-0043, at pgs. 10-11.
---------------------------------------------------------------------------
After considering these comments and other information, NHTSA is
modifying the specification for door velocity. NHTSA added this
specification because Takata had demonstrated \178\ that when the door
velocity reduces by more than 4 km/h during the interaction with the
sliding seat, the HIC values and chest deflections measured on the Q3s
were significantly reduced. However, as discussed further below,
because NHTSA is specifying a relative velocity corridor between the
door and the sliding seat--in addition to specifying the sliding seat
acceleration corridor and the door velocity at the time of contact with
the sliding seat--specifications of the door velocity during the
interaction of the sliding seat can be widened to some extent. NHTSA's
testing with the final SISA configuration showed that the sled/door
velocity reduced 1.66 to 1.89 km/h during the interaction with the
sliding seat, from the door velocity at time of initial contact with
the sliding seat.\179\ In order to ensure satisfactory reproducibility
of the side impact test while providing reasonable flexibility to
testing facilities to conduct the test, NHTSA is specifying that the
door (sled) velocity during interaction with the sliding seat not
decrease beyond 2.5 km/h from the door velocity at the time the door
structure contacts the sliding seat. NHTSA believes that if the door
velocity reduces beyond 4 km/h during the interaction with the sliding
seat, it may not be possible to meet the specifications for the sliding
seat acceleration corridor or the relative velocity corridor. This is
discussed in more detail below.
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\178\ Study of Global Road Safety Partnership (GRSP) side impact
testing. Takata Corporation. November 10, 2011. Docketed with this
final rule.
\179\ Interaction with the sliding seat is considered to be
during the period from time T0, when the sliding seat is
first impacted by the door assembly, to the time when acceleration
of the sliding seat reaches 0 G, usually between 48 and 58 ms from
T0.
---------------------------------------------------------------------------
4. Relative Door Velocity Profile
The 2014 NPRM proposed a door impact velocity and a sliding seat
acceleration profile and requested comment on whether a relative door
velocity profile should also be specified. NHTSA stated that a relative
door velocity profile (with respect to the sliding seat) may be
desirable to ensure a more reproducible interaction of the intruding
door with the child restraint in different types of sled systems, and
requested comments on the need for specifying a relative door velocity
profile to improve reproducibility of the test procedure. NHTSA stated
that, depending on whether the agency received information sufficiently
supporting such a velocity profile, one may be included in the final
rule.
Response to Comments
Dorel supported the inclusion of two separate velocity profiles,
one for the bottom part of the sled that has the door and one for the
sliding seat.\180\ Dorel believed that two velocity profile
specifications would provide improved parameters for repeatability at
individual test facilities and improved reproducibility between test
facilities.\181\
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\180\ The sled carriage is the bottom part of the sled, and the
sliding seat is on top of that.
\181\ Dorel stated that, if sufficient repeatability and
reproducibility were later validated, it would not object to the
simplification of the requirement at that time.
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NHTSA has determined that specifying a door velocity profile
relative to the sliding seat will improve the reproducibility of the
interaction of the intruding door with the child restraint, and thus
has defined the relative velocity between the sled door and the sliding
seat. This is consistent with Dorel's suggestion of having two separate
velocity profiles. Since the relative velocity is calculated using the
velocities of the sled carriage and the sliding seat, it would be
controlling both velocities to improve the repeatability and
reproducibility throughout the event, not only at impact. If these
velocities are not controlled, it may be possible to create different
velocity profiles with more fluctuations that may result in different
injury measures. The impact speed at time T0 (the time at
which the door contacts the sliding seat structure) is the relative
velocity between the sled door and the sliding seat. While in an
acceleration-type sled the velocity of the sliding seat is close to
zero, there is some slight movement of the sliding seat before impact
with the door assembly, and this movement may vary at each test
facility. In a deceleration-type sled, the velocity of the sled door is
zero at the time of the impact of the door assembly with the sliding
seat. Each test facility will have to tune its system to determine the
necessary velocity of the sled door to achieve the required relative
velocity at the time of impact (T0) with the honeycomb,
regardless of whether it is done in an acceleration-type or
deceleration-type sled system.
Graco commented against a relative velocity profile, believing this
to possibly over-constrain the system. Graco requested that NHTSA
provide data demonstrating that a CRS tested on both a deceleration and
an acceleration sled would provide the same end results given that the
test meets the currently defined constraints (door velocity
requirements and sliding seat velocity/acceleration requirements). In
response, NHTSA's demonstration of repeatability and reproducibility
using both a deceleration and acceleration sled is discussed in the
section below, ``Reproducibility and Repeatability.''
JPMA stated that, contrary to what was stated in the NPRM preamble,
the proposed regulatory text for S6.1.1(b) specified a sliding seat
acceleration pulse and a relative door velocity, but not a door
velocity. JPMA added that the proposed regulatory text included a
specification that the velocity of the sled be the same as the relative
door velocity.
The NPRM proposed a specification to ``accelerate the test platform
to achieve a relative velocity (V0) of 31.3 0.8
km/h in the direction perpendicular to the seat orientation reference
line \182\ (SORL) between the SISA sliding seat and the door assembly
at the time they come in contact (T0).'' This is not the
same as proposing a specific door (sled) velocity profile; instead it
is a specification that this door velocity could not be reduced more
than 1 km/h during the interaction with the sliding seat. The door
velocity and the ``relative door-sliding seat velocity'' are not
necessarily the same. The velocity of the door relative to the sliding
seat refers to the velocity difference between the door and the sliding
seat. If the sliding seat velocity is equal to zero, the door velocity
and the relative velocity of the door and sliding seat would be the
same, but as there is some slight movement of the sliding seat prior to
impact, the velocity of the door and the relative velocity of the door
and sliding seat are not the same. In this final rule, NHTSA is
adopting not only a relative velocity at time of impact of the door
assembly with the sliding seat, but also a relative velocity corridor
throughout the event (relative velocity corridor).
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\182\ Seat orientation reference line means the horizontal line
through Point Z as illustrated in Figure 1 of S4 in the regulatory
text of the NPRM.
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In the December 15, 2021 meeting, JPMA \183\ requested that NHTSA
specify an incoming sled carriage pulse corridor to reduce lab-to-lab
test variability.
[[Page 39277]]
Additionally, JPMA requested adding bracing and structural improvements
to the door assembly to eliminate dampened oscillatory motions during
testing.
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\183\ Supra, see Docket No. NHTSA-2014-0012.
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NHTSA disagrees with JPMA regarding the need to specify an incoming
sled carriage acceleration pulse to minimize lab-to-lab variability.
The testing at VRTC and at Kettering,\184\ detailed in Section IX,
demonstrated that specifications for the sliding seat acceleration
profile corridor, the relative velocity at impact time, and the
relative door velocity profile corridor are sufficient to ensure
adequate reproducibility of the test not only at different test
facilities but also when using different types of sled systems
(deceleration and acceleration sled systems) where the incoming sled
carriage acceleration pulses can be very different. Regarding
rigidizing the door assembly, NHTSA does not see the need for it. While
there may be some door oscillations, the side impact test has been
validated against vehicle tests (which also showed door oscillations)
and has consistently produced repeatable results in tests conducted at
VRTC and Kettering. As long as the relative door velocity and the
sliding seat accelerations are within required specifications
(including the relative door velocity profile corridor adopted in this
final rule), there is no need to make further structural improvements
to the door assembly.
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\184\ Wietholter, K. & Louden, A. (2021, November).
Repeatability and Reproducibility of the FMVSS No. 213 Side Impact
Test. Washington, DC: National Highway Traffic Safety
Administration.
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TRL recommended, based on its experience, that a relative velocity
should be specified to ensure consistent test input conditions between
test facilities. TRL commented that the side impact test in ECE R.129
was developed on a deceleration sled and that TRL validated this method
for the European commission. TRL explained that this validation
included investigating the repeatability and reproducibility of the
test method as well as validating it against full scale crash tests.
TRL added that this experience showed that the door-sled relative
velocity is an important factor to control, and that without a control
on this parameter the test severity can vary.
MGA commented that input constraints for just the sliding seat
acceleration and relative sliding seat/door velocity limit should be
sufficient.
NHTSA agrees with TRL that the velocity of the door relative to the
sliding seat at the time the honeycomb contacts the sliding seat and
throughout the side impact event is an important parameter that should
be specified in this final rule. Figure 9 shows the average (dotted
line) and the upper and lower boundaries (solid lines) of the velocity
profile for the door relative to the sliding seat in sled tests
performed during the development of the test procedure prior to the
NPRM. The upper and lower boundaries of the relative door velocity
represent the maximum and minimum values of the relative door velocity
profiles in these sled tests.
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After consideration of comments and other information, NHTSA has
decided to include a requirement for the relative door velocity with
respect to the sliding seat to control the door interaction with the
sliding seat and CRS throughout the event. Further, TRL had commented
that a defined range for door intrusion is a factor affecting the
severity of the test and should be defined to ensure consistent test
conditions. The relative door velocity specification in this final
[[Page 39278]]
rule will also control the intrusion of the door into the seat
compartment.
The coordinates of the relative velocity corridor are defined in
the regulatory text. Using data from testing with the updated sliding
seat design in two laboratories (see Figure 10), NHTSA developed a
slightly different relative door velocity corridor with respect to the
sliding seat from that presented in the preamble of the NPRM. This
corridor is wider than the corridor in the NPRM to allow more
flexibility in conducting the test at different test facilities while
maintaining good repeatability and reproducibility. While Graco
commented that a relative velocity corridor may over-constrain the
system, we believe a relative velocity corridor is necessary to control
the velocity throughout the event, which will help maximize
repeatability and reproducibility.
[GRAPHIC] [TIFF OMITTED] TR30JN22.013
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5. Relative Velocity at Impact Time (T0)--Tolerance
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\185\ Tests that were within new relative velocity tolerance at
impact time conducted at VRTC in April 2017 and November 2017.
\186\ Tests that were within new relative velocity tolerance at
impact time conducted at Kettering University in 2016.
---------------------------------------------------------------------------
NHTSA proposed an impact (T0) relative velocity
(V0) of 31.3 0.8 km/h, meaning at time of
impact of the door with the sled, the relative velocity is within 31.3
+/-0.8 km/h. The agency performed a series of tests to determine the
effect of the relative velocity at time T0 on performance
measures. NHTSA intended to conduct three tests of a CRS model by
varying the relative velocity at time T0 within a range of
1.6 km/h to cover the allowable range in velocity; however, one of the
tests performed at the lower speed (30.28 km/h) fell out of the
allowable relative velocity limits of 30.5 km/h to 32.1 km/h. Table 17
below shows the results of these repeat tests.
Table 17--Sensitivity Analysis of the Relative Velocity of the Door With Respect to the Sliding Seat at Time of
Impact (Time T0) With the Q3s ATD in a Graco Ready Ride CRS Installed Forward-Facing Using CRAS.
----------------------------------------------------------------------------------------------------------------
Impact
Chest relative Impact
Database test No. CRS HIC15 deflection velocity [km/ relative
[mm] h] velocity [mph]
----------------------------------------------------------------------------------------------------------------
10279......................... Graco Ready Ride 587 20.45 30.28 18.82
10273......................... ................ 723 19.82 31.06 19.29
10272......................... ................ 771 21.48 31.99 19.88
----------------------------------------------------------------------------------------------------------------
Average......... 693.66 20.58 .............. ..............
Std Dev......... 77.67 0.68 .............. ..............
CV %............ 11 3 .............. ..............
----------------------------------------------------------------------------------------------------------------
[[Page 39279]]
Results showed that coefficient of variation (CV) \187\ values for
HIC15 reached 11 percent and chest deflection only 3 percent. Given the
slightly high CV values for HIC15 at the extreme ranges, NHTSA
concluded that reducing the tolerance for the specified relative
velocity would be beneficial to control repeatability and
reproducibility. NHTSA updated the impact relative velocity and
tolerance to 31.3 0.64 km/h (instead of 31.3
0.8 km/h) to better achieve the desired repeatability and
reproducibility within the parameters of sled systems. Both
acceleration (at VRTC) and deceleration (at Kettering) sled systems
were able to consistently produce impact relative velocity within the
specified reduced relative velocity tolerance levels. Tests results
with relative velocities within the reduced tolerances showed good
repeatability and reproducibility, and are discussed in more detail in
Section IX.
---------------------------------------------------------------------------
\187\ The percent coefficient of variation (%CV) is a measure of
variability expressed as a percentage of the mean.
---------------------------------------------------------------------------
6. Longitudinal Crash Component
NHTSA determined the impact angle of the sled buck using data from
the same ten small vehicle FMVSS No. 214 tests that were used to derive
the acceleration corridor and door velocity. NHTSA evaluated the effect
of the test buck's impact angle on dummy kinematics and injury
responses through a range of testing at 0, 10, 15, and 20 degrees.
Based on the tests and average impact angle calculated from the FMVSS
No. 214 tests, NHTSA selected a 10-degree impact angle as the most
appropriate. NHTSA found that a 10-degree impact angle on the sled test
produced dummy responses closer to those measured by the ATD in the
same CRS in the four MDB crash tests than the other impact angles. This
work was described in detail in NHTSA's 2009 Initial Evaluation
study.\188\
---------------------------------------------------------------------------
\188\ Sullivan et al. (2009).
---------------------------------------------------------------------------
Dorel and JPMA noted that during sled tests conducted by the agency
for the proposed rule, the child dummy experienced what the commenters
described as artificial forward head movement before crash impact.
Dorel described that the CRS seat back pulls away from the head in the
agency's sled side impact test video (100629-3) prior to T0
(T0 being time of contact of the sliding seat with the door
assembly). Dorel believed this movement to be an artifact of the 10-
degree fixture angle and the pre-test distance of the sliding seat from
the side door assembly.
Dorel stated that the sliding seat is positioned sufficiently away
from the side door to allow the sled to reach a desired velocity (31.3
km/h) prior to the time the sliding seat starts to accelerate to a
specific acceleration profile. The commenter stated that, during this
run up time and prior to the interaction of the sliding seat with the
door, the CRS seat back pulls away from the head. Dorel further stated
that, in accordance with Newton's 1st law that an object at rest (in
this case, the head) will stay at rest unless an external force acts
upon it (in this case the CRS pulling the ATD torso), the ATD's head is
tilted forward prior to the interaction of the striking vehicle and
door.
Dorel provided data showing that the measured head displacement in
sled tests with its forward-facing Safety 1st Air Protect CRS appeared
to be as much as 86 mm (3.4 in) at T0 and 185 mm (7.3 in) at
T0+29 msec.\189\ Dorel noted that during this period, the
dummy head remained in the center of the main sled rails while the 10-
degree rails with the sliding seat pulled the CRS laterally away from
the head. Dorel stated that this motion placed the head out of position
in relation to the side wings of the CRS prior to impact and thus
artificially deprived the dummy of the benefit of the side wing
protection, and may artificially increase the measured injury values.
Dorel stated its belief that this head motion appeared to react like
pre-crash braking prior to the vehicle being struck in its side, which
is not apparent in the FMVSS No. 214 MDB crash test video or data.
Dorel explained that the FMVSS No. 214 test method does not incorporate
pre-crash braking of the struck vehicle prior to MDB side crash in its
simulation.
---------------------------------------------------------------------------
\189\ See NHTSA-2014-0012-0035, at pg. 3. In Dorel's first
comment submission it reported a head displacement between 48 mm
(1.9 in) to 54 mm (2.1 in).
---------------------------------------------------------------------------
As additional support for this proposition about the artificiality
of the proposed test, Dorel described a 2014 full scale, vehicle-to-
vehicle side impact test conducted by Transport Canada Research &
Development. Dorel explained that the struck vehicle in this test was a
2011 model year passenger car with the near side rear passenger
position occupied by a Q3s dummy restrained by the internal harness of
a forward-facing Alpha Elite (Non-Air Protect Model) CRS installed
using the lower anchors of a child restraint anchorage system \190\ and
tether. Dorel provided screenshots of the dummy kinematics during the
test and noted that at T0-65 and T0, there was no
head displacement, while measurement from T0 to
T0+29 showed ~24mm lateral movement of the Q3s dummy
head.\191\ Dorel also referenced a 2002 New Car Assessment Program side
impact (SINCAP) test series that included CRSs in rear seating
positions, where the ATD did not experience pre-crash head motions.
Dorel provided still photographs of the dummy from a test with the
Nissan Sentra with a Dorel Triad CRS installed in the rear seat.\192\
Dorel stated that the photographs illustrate the same T0
head motion references as the Transport Canada tests.
---------------------------------------------------------------------------
\190\ See 49 CFR 571.225.
\191\ See NHTSA-2014-0012-0045, at pg. 3.
\192\ Id.
---------------------------------------------------------------------------
Dorel referenced its proposed test procedure (the Dorel-Kettering
method proposed in a May 2009 petition, discussed above) that did not
exhibit pre-crash event head motion. Dorel commented that the Dorel-
Kettering method did not induce unintended head motion prior to
T0 (as the seat assembly is stationary at the time of
impact). The commenter emphasized that the head motion of the ATD is
not observed in the FMVSS No. 214 MDB tests that the agency used as the
basis for NHTSA's proposed test method for FMVSS No. 213a and that
Dorel used to develop its Dorel-Kettering side impact test.
Agency Response
The FMVSS No. 214 and the side NCAP crash tests are conducted with
a stationary target vehicle, so there is no dummy head movement
expected prior to impact. The MDB impacts the target vehicle at a
crabbed angle (27 degrees) simulating a side impact of the target
vehicle traveling at 24 km/h (15 mph) by the striking MDB traveling at
48 km/h. With the FMVSS No. 213a test procedure, the 10-degree angle of
the motion of the sliding seat with respect to the sled system was to
reproduce the longitudinal loading on the vehicle simulated in the
FMVSS No. 214 vehicle test. The Dorel-Kettering test procedure does not
have the capability of simulating this longitudinal component of the
impact, which the agency believes is a limitation of their test. The
longitudinal component of the impact is important to reproduce since
real world data indicate that most side vehicle crashes have a
longitudinal crash component.
As discussed in the NPRM, data indicate that child restraints
should be designed to account for both longitudinal and lateral
components of the direction of force in a side crash. Sherwood found
that most side crashes
[[Page 39280]]
had a longitudinal crash component.\193\ A comparison of results of
sled tests with the same door impact velocity conducted using the
Dorel-Kettering method and the proposed FMVSS No. 213a side impact test
showed that the dummy injury measures were consistently lower using the
Dorel-Kettering test method. Dorel did not present any data
demonstrating that the dummy responses in the Dorel-Kettering sled
tests are similar to those observed in vehicle crash tests, while such
data were provided in the NPRM. NHTSA believed the Dorel-Kettering test
procedure needed further development to represent the crash environment
experienced by children in child restraints in near-side impacts, and
decided the test method would not protect children in side impacts as
completely as the proposed FMVSS No. 213a test procedure.
---------------------------------------------------------------------------
\193\ Sherwood, et al. ``Factors Leading to Crash Fatalities to
Children in Child Restraints,'' 47th Annual Proceedings of the
Association for the Advancement of Automotive Medicine, September
2003.
---------------------------------------------------------------------------
The agency tracked head motion during its repeatability and
reproducibility test series (discussed further below) at VRTC and
Kettering to quantify dummy head nodding (forward displacement) during
the test. The tests performed at VRTC and Kettering used the proposed
FMVSS No. 213a test procedure. As shown in Table 18, the average head
displacement at the time of impact with the door assembly
(T0) was 48.9 mm at VRTC and 62.1 mm at Kettering. The
maximum range of head forward displacement in the X-direction at
T0 in the VRTC tests was 6.4 mm and 14.6 mm in the Kettering
tests. Differences in head position at time of impact between VRTC and
Kettering for the same CRS ranged from 17.4 to 59.5 mm. The difference
in the position of the head at the time T0 in a test
facility or between the two test facilities did not translate into
unacceptable variability in the performance measures as shown in the
repeatability and reproducibility analysis, discussed further below.
Instead, the difference in head position was attributable to the
longitudinal crash component in the FMVSS No. 213a test, an aspect of a
side crash present in real-world intersection-type crashes.
NHTSA concurs with Dorel that there is forward head displacement
prior to time T0 in the proposed FMVSS No. 213a test.
However, this displacement realistically reflects real-world side
crashes, as struck vehicles in side impacts are usually travelling
forward, and reflects the FMVSS No. 214 vehicle-to-vehicle side crash.
The forward head displacement is not a test artifact that renders the
FMVSS No. 213a test artificial; rather, it is an indicator of the
representativeness of the test. Accordingly, NHTSA did not make any
changes to the test procedure impact angle.
BILLING CODE 4910-59-P
[[Page 39281]]
[GRAPHIC] [TIFF OMITTED] TR30JN22.015
BILLING CODE 4910-59-C
d. Test Set Up and Procedure
---------------------------------------------------------------------------
\194\ TEMA means ``TrackEye Motion Analysis'' software.
---------------------------------------------------------------------------
The proposed test procedure specified how child restraints would be
installed and positioned on the sliding seat. In short, NHTSA proposed
that:
CRSs other than boosters would be attached to the SISA
with the CRAS lower attachments and the child restraint's top tether
would be attached if the owner's manual instructed consumers to attach
the tether;
Belt-positioning booster seats would be tested with Type 2
(lap and shoulder) belts; and,
The CRS would be installed centered on the sliding seat,
with the
[[Page 39282]]
front face of the armrest on the door approximately 32 mm (about 1.25
inches) from the edge of the sliding seat (towards the CRS) at the time
the honeycomb interacts with the sliding seat structure.
The Q3s dummy would be positioned in the child restraint
according to the manufacturer's positioning procedures.
A CRS that is recommended by its manufacturer for use
either by children having a mass between 5 and 10 kg (11 to 22 lb) or
by children with heights between 650 and 850 mm, (25.6 and 33.5 inches)
would be tested with the 12-month-old CRABI.
A CRS that is recommended by its manufacturer for use
either by children having a mass between 10 and 18.1 kg (22 to 40 lb)
or by children with heights between 850 and 1100 mm, (33.5 and 43.3
inches) would be tested with the Q3s dummy.
1. CRS Attachment
i. Lower Anchor and/or Seat Belt CRS Installation
FMVSS No. 213 currently requires most types of CRSs to meet the
frontal crash requirements both when secured to the vehicle seat
assembly with a vehicle belt, and when secured by a child restraint
anchorage system (CRAS) (S5.3.2).\195\ The 2014 side impact NPRM
proposed to test CRSs other than booster seats with just the CRAS, as
preliminary tests showed similar performance by the seats when attached
by CRAS or by a Type 2 belt.\196\ NHTSA requested comments on whether
the proposed standard should also require these car seats to meet FMVSS
No. 213a when attached to the seat assembly with a belt system.\197\
Under the NPRM, belt-positioning booster seats subject to the standard
would be tested with a Type 2 belt.\198\
---------------------------------------------------------------------------
\195\ The belt system currently specified in FMVSS No. 213 is a
lap belt (Type 1 belt). The November 2, 2020 NPRM proposed changing
the belt to a lap/shoulder belt (Type 2 belt).
\196\ As the original Takata test sled only had a Type 2 belt
system, NHTSA modified the test bench seat to incorporate a child
restraint anchorage system.
\197\ 79 FR at 4589, col. 2.
\198\ When the 2014 NPRM was published, it was possible for
booster seats to be subject to the proposed standard, if such
boosters were sold for children weighing less than 18.1 kg (40 lb).
However, the November 2, 2020 NPRM proposed to amend FMVSS No. 213
so that booster seats could not be sold for children weighing less
than 18.1 kg (40 lb). If the November 2020 proposal is adopted,
booster seats will not be permitted to be sold for children weighing
less than 18.1 kg (40 lb)--so the side impact requirements of FMVSS
No. 213a will not apply.
---------------------------------------------------------------------------
Comments Received
Many commenters recommended that NHTSA conduct CRS testing under
two different installation modes: by CRAS and by a 3-point lap/shoulder
(Type 2) seat belt system.
Safe Ride News (SRN) argued that both a CRAS and a belt
installation should be tested, as children under 18.1 kg (40 lb) will
frequently be in a CRS that is installed with a seat belt due to the
predisposition of some caregivers not to use CRAS, or the lack of lower
anchors in a vehicle position (e.g., the center rear seat of the second
row on most vehicles). SRN argued that non-passing results would compel
manufacturers to improve their CRS designs for both lower anchor
attachments and for seat belt attachment, and ensure an adequate
routing of the seat belt ``path'' through the CRS to meet the side
impact standard. SRN also requested the agency to provide the data
supporting NHTSA's statement in the NPRM that the performance of the
child restraints, when using CRAS and the belt system, were similar.
Britax and JPMA commented in support of the use of the Type 2 belt
system, arguing that the majority of vehicles in the current fleet now
have lap/shoulder belts across the rear seating compartment, and the
use of Type 1 belts for testing is not consistent with the majority of
in-vehicle belted installations. UPPAbaby also supported use of a Type
2 belt test as presenting a ``realistic situation in the majority of
vehicles today.''
Mr. Hauschild believed that NHTSA's finding that ``the Type II
[sic] belt system showed similar performance metrics to that obtained
when the CRSs were attached using [CRAS]'' was contrary to other
research that examined CRAS and belt anchors.\199\ He believed that CRS
testing should include both CRAS and Type 2 belt systems, and that
further studies may be needed to compare the performance of CRAS and
Type 2 belts for side impact events.
---------------------------------------------------------------------------
\199\ The commenter referred to research that found there is
less excursion using the CRAS compared to vehicle belts. In
evaluating the comment, we determined that the research to which the
commenter refers studied differences in performance involving far-
side impacts. NHTSA's statement on the two different attachment
methods having similar performance was referring to near-side impact
tests where paired comparisons using different CRS installation
methods resulted in HIC15 and chest deflection results that were not
significantly different. We have not engaged in studies to assess
the far-side performance of CRSs so we cannot confirm the findings
of the study cited by Mr. Hauschild.
---------------------------------------------------------------------------
Advocates recommend that each CRS be required to pass the proposed
testing under all installation conditions specified by the manufacturer
in its owner instructions for the specific restraint. Advocates stated
that, if a CRS can be installed with CRAS, a Type I belt, or a Type 2
belt without the top tether, then it should be required to pass the
proposed tests under all those conditions to ensure that the child will
be offered the proper amount of protection regardless of the
installation method selected by the caregiver.
Consumers Union (CU) also supported testing CRSs with both the CRAS
attachment and Type 2 belts. CU stated that Type 2 belts are prevalent
in current model vehicles, often occupy different belt paths on the
child restraint than the CRAS belts, and use different ``lockoff''
mechanisms than in CRAS installations. (Lockoff refers to the use of
CRS components that cinch or clamp the vehicle seat belt to prevent
loosening of the seat belt. In some cases, CRS lockoffs, which vary by
CRSs, can be used in lieu of ``locking'' the vehicle seat belt
retractor using the standardized lockability feature of a vehicle's
seat belt.) CU also stated that Type 2 belts may allow some additional
``pivoting'' of seats around their ``buckle'' side that may not be seen
with CRAS, which may be critical to a comprehensive review of side
impact performance. The commenter also referred, as did SRN and JPMA,
to FMVSS No. 213's labeling requirements that restrict use of CRAS to
where the combined weight of the CRS and child is less than 29.5 kg (65
lb). These commenters argued that this restriction on CRAS use will
likely produce a trend toward increased use of seat belts to install
CRSs, particularly forward-facing CRSs and restraints recommended for
heavier children. The commenters argued that NHTSA's not requiring
testing of the seat belt installation would overlook this prominent
mode of use. However, CU stated, as did JPMA and Britax,\200\ that
testing with Type 1 (lap only) belts should not be considered as lap
belts are rarely seen in current model vehicles. They further argued
that a lap belt test is not necessary because most CRSs are designed so
that the lap belt attachment and loading path are the same as those
used by CRAS straps.
---------------------------------------------------------------------------
\200\ Britax stated that requiring testing under FMVSS No. 213a
with the Type 1 belt installation would unnecessarily increase the
efforts and expense of testing, with minimal real-world benefits.
---------------------------------------------------------------------------
NTSB commented that parents or caregivers may choose to install a
CRS using the vehicle's seat belt for many reasons, including ease of
installation and a lack of seating positions with lower CRAS
attachments. NTSB stated
[[Page 39283]]
that an analysis of 79,000 CRS checklist forms by Safe Kids USA
confirmed that approximately 60 percent of the examined CRSs were
installed with seat belts. The commenter believed that, given the
prevalence of seat belt installations, safety would be better served by
requiring the CRS to be tested under all vehicle securement conditions.
Furthermore, NTSB argued, because the proposed rule focused on
assessing the capability of the CRS to maintain its structural
integrity, requiring the restraint system to be tested in all
installation options would ensure the strength of the entire seat
system, including the multiple routing options for various types of
seat belts. NTSB added that, because the dynamics of the CRS
interaction with the intruding vehicle door are integral to the test,
the orientation of the seat at the point of impact may affect the
kinematic response of the dummy. NTSB argued that varied installation
options may result in slightly different seat orientations when the
seat interacts with the intruding door, which will affect the outcome
of the test. NTSB concluded that testing all installation options would
further ensure that CRSs provide adequate safety.
NTSB further argued that, since the testing cost estimated by NHTSA
is less than $0.01 per CRS, requiring manufacturers to conduct the same
tests under three securement conditions--CRAS, Type 1 seat belts, and
Type 2 seat belts--would not be burdensome, and would be well worth the
effort to ensure that the CRS provides the intended level of side
impact protection, regardless of how it is attached to the vehicle.
NTSB encouraged NHTSA to revise the proposed rule to require testing
with the CRS attached to the SISA using the lower anchorage
attachments, a Type 1 seat belt, and a Type 2 seat belt.
In contrast to the above, IIHS and Graco stated that testing only
with the CRAS configuration was sufficient. IIHS believed it was
reasonable to forgo testing with lap and shoulder belts as NHTSA found
no meaningful difference in performance in preliminary testing
comparing CRSs attached with lower anchors with those attached with
seat belts. Based on NHTSA's results showing that Type 2 CRS
installations perform the same as CRAS CRS installations, Graco
recommended only testing with CRAS.
Dorel did not expressly recommend CRAS or seat belt installation
for testing, but provided data indicating CRAS testing showed little
difference in the HIC and chest deflection data when compared to Type I
(lap) tests.\201\
---------------------------------------------------------------------------
\201\ NHTSA-2014-0012-0045, at pg. 6.
---------------------------------------------------------------------------
Agency Response
After considering the comments and other information, NHTSA has
decided there is a safety need to assess CRSs performance in a Type 2
belt test in addition to the CRAS test. Based on a review of the
comments and an assessment of current CRS designs, NHTSA concludes that
both tests are necessary to evaluate CRS performance properly,
particularly regarding the structural integrity of the restraint when
subjected to crash forces imposed on the restraint using the different
loading paths.
Among NHTSA's preliminary tests for the NPRM \202\ were four (4)
paired tests to compare CRS performance when installed with lower
anchors and with 3-point (Type 2) seat belt. Paired comparisons showed
that HIC15 and chest deflection results with the different installation
methods were not significantly different (p>0.05), as seen in Table 19,
below.
---------------------------------------------------------------------------
\202\ See Sullivan et al. (2013) for results of these tests.
Table 19--Paired Test Results for Comparing the Performance of CRSs Installed Using Lower Anchors (LA Only) and Using 3-Point Lap-Shoulder Belts (SB3PT)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Chest
Database test No. Dummy CRS Orientation Attachment HIC15 deflection Head-door contact
method [mm]
--------------------------------------------------------------------------------------------------------------------------------------------------------
9624........................ Q3S Graco Comfort Sport. RF Convertible. LA Only........ 729 26.9 Yes.
9622........................ Q3S Graco Comfort Sport. RF Convertible. SB3PT.......... 793 23.1 Yes.
8260 *...................... Q3s Graco My Ride....... RF Convertible. LA Only........ 751 25.0 No.
8264 *...................... Q3s Graco My Ride....... RF Convertible. SB3PT.......... 681 31.0 No.
8265 *...................... Q3s Cosco Scenera....... RF Convertible. LA Only........ 748 34.0 Yes.
8266 *...................... Q3s Cosco Scenera....... RF Convertible. SB3PT.......... 748 28.0 Yes.
9633........................ Q3S Graco Comfort Sport. FF Convertible. LA Only........ 579 23.0 Yes.
9632........................ Q3S Graco Comfort Sport. FF Convertible. SB3PT.......... 649 19.1 Yes.
8253 *...................... Q3S Evanflo Chase....... FF Converrible. LA Only........ 987 20 Yes.
8257 *...................... Q3S Evenflo Chase....... FF Convertible. SB3PT.......... 784 25 Yes.
8252 *...................... Q3s Evenflo Triumph FF Combination. LA Only........ 446 16.0 No.
Advantage DLX.
8256 *...................... Q3s Evenflo Triumph FF Combination. SB3PT.......... 479 13 No.
Advantage DLX.
8258 *...................... 12MO Graco My Ride....... RF Convertible. LA Only........ 755 N/A No.
8261 *...................... 12MO Graco My Ride....... RF Convertible. SB3PT.......... 748 N/A No.
9626........................ 12MO Combi Shuttle....... RF Infant...... LA Only........ 478 N/A Yes.
9625........................ 12MO Combi Shuttle....... RF Infant...... SB3PT.......... 438 N/A Yes.
9628........................ 12MO Safety 1st OnBoard RF Infant...... LA Only........ 625 N/A No.
35.
9627........................ 12MO Safety 1st OnBoard RF Infant...... SB3PT.......... 615 N/A No.
35.
8259 *...................... 12MO Combi Shuttle....... RF Infant...... LA Only........ 450 N/A Yes.
[[Page 39284]]
8262 *...................... 12MO Combi Shuttle....... RF Infant...... SB3PT.......... 521 N/A Yes.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Preliminary tests from NPRM.
Note: SB3PT means 3-point belt, LA Only means lower anchorages of the child restraint anchorage system, RF means rear-facing and FF means forward-
facing.
It was on those data that NHTSA made a preliminary determination
that the differences in performance of the restraints were not
significant based on the method of installation. However, NHTSA now
agrees that testing a CRS in both installation modes (using CRAS and a
Type 2 (lap and shoulder) belt) will more appropriately evaluate CRS
performance, including structural integrity, under the different
loading paths in a CRAS installation and in a seat belt installation.
The agency agrees with the commenters supporting inclusion of a
Type 2 belt attachment test that, while many CRSs share the same belt
paths for lower anchorages and seat belt installations, there are some
CRSs that do not (such as CRSs that use a rigid CRAS lower attachment
or like the Britax Clicktight seats \203\). Testing in both attachment
modes is needed for a more effective evaluation of the side loading of
the CRS in a side crash, as the different points of attachment of the
CRS to the vehicle seat and the different routing paths of the vehicle
seat belt through the CRS can affect how the CRS is loaded by the seat
belt during the side impact event.
---------------------------------------------------------------------------
\203\ ClickTight Installation Systems in Convertible Car Seats,
Britax, https://web.archive.org/web/20201201232308/https://us.britax.com/product-knowledge/articles/clicktight-convertibles/.
---------------------------------------------------------------------------
NHTSA also agrees with commenters that testing with a Type 2 belt
configuration is appropriate because of the CRAS weight restrictions.
Under current FMVSS No. 213, child safety seats manufacturers must
instruct owners not to use the CRAS lower anchors if the mass of the
seat, combined with the mass of the child for whom the CRS is
recommended, exceed 29.5 kg (65 lb). Caregivers are instead instructed
to use the vehicle's belt system to install the CRS. As the provisions
of FMVSS No. 213 envision Type 2 belt installations as vital to CRS
installations, it is prudent for the agency to adopt a Type 2 belt test
in FMVSS No. 213a to ensure all safety seats for children weighing less
than 18.1 kg (40 lb) provide adequate side impact protection. Further,
data show that a substantial portion of caregivers in the field use
seat belts, rather than CRAS, to install CRSs.\204\ For the above
reasons, adopting a Type 2 belt test in addition to a CRAS test best
meets the MAP-21 mandate to improve the protection of children seated
in CRSs in side crashes.
---------------------------------------------------------------------------
\204\ NCRUSS found that 34% of rear-facing infant carriers, 23%
of rear facing convertible and 44% of forward-facing CRSs were
installed with seat belts.
---------------------------------------------------------------------------
As to the type of belt system, NHTSA believes that just a Type 2
belt test is appropriate, not both a Type 1 belt (lap belt) test and a
Type 2 belt test. NHTSA agrees with CU and Britax that a Type 1 seat
belt configuration is rare in the light passenger vehicle fleet and
should not be adopted as a test configuration for lack of a safety need
for such a test. In the November 2, 2021 NPRM upgrading the frontal
impact sled test, NHTSA proposed to use a Type 2 seat belt instead of a
Type 1 seat belt for the same reasons, i.e., Type 1 configurations are
mostly unavailable in the vehicle fleet.\205\ Given the prevalence of
Type 2 belts in the rear seats of current passenger vehicles, testing
CRSs with the type of seat belt caregivers would be using better
ensures the representativeness of the compliance test.
---------------------------------------------------------------------------
\205\ The NPRM also proposed to amend FMVSS No. 213 to require
child restraints to meet the requirements of Standard No. 213 when
attached by the Type 2 belt and to remove the requirement that CRSs
must meet the standard when attached by a Type 1 (lap) belt.
---------------------------------------------------------------------------
In supporting use of a Type 2 belt test, UPPAbaby also asked about
a ``carrier only configuration,'' and suggested ``this should be taken
into account as a possible use situation, and added to the proposed
rulemaking, again using a Type II [sic] belt configuration.'' NHTSA
understands the commenter as suggesting that FMVSS No. 213a should
require infant carriers designed with a detachable base to be tested
without their base in a Type 2 belt. The agency will test infant
carriers with bases with CRAS and with a Type 2 belt, but, for now, the
agency has decided not to test the carriers without their bases. The
agency conducted two tests of infant carriers with no base (Evenflo
Discovery and Combi Shuttle) and both showed no head to door contact.
The agency has not conducted extensive testing on infant carriers
without the base, but the testing suggests that infant carriers can
meet the standard with and without a base. Thus, NHTSA does not find
justification to add another test of the restraints to check
performance of the carriers when the base is not used.
The drawings for the SISA that were placed in the docket for the
NPRM show the proposed Type 2 seat belt configuration. The final
version of the drawings incorporated by reference by this final rule
also depict the Type 2 seat belt anchorages.
MGA commented that the NPRM did not include provisions about the
configuration of the belt anchor on the inboard side of the lap belt of
the Type 2 belt for Type 2 installation configurations. MGA stated that
FMVSS No. 213 requires the belt anchor to lock the belt, while a
similar Transport Canada standard (Canadian Motor Vehicle Safety
Standard No. 213) incorporates a freely-sliding belt anchor.\206\ MGA
argued that, since most vehicles in the fleet have a free-sliding belt
buckle tongue on the inboard side, it makes more sense to replicate
this condition. MGA suggested that, if the Type 2 belt in FMVSS No.
213a were to have a freely-sliding belt anchor, FMVSS No. 213 should be
updated in the future as well.
---------------------------------------------------------------------------
\206\ A freely sliding belt anchor is a load bearing device
through which the seat belt webbing may freely pass and change
direction. The belt anchor is bolted to the SISA. The freely sliding
belt anchor is similar in design and function to a guide loop used
to properly position the torso portion of the webbing of a driver's
seat belt.
---------------------------------------------------------------------------
The final drawing package of the SISA details the design of the
belt anchorages and hardware used in the Type 2 seat belt
installations, as they will be part of the FMVSS No. 213a
configuration. The final drawing package incorporates an inboard freely
sliding belt anchor as suggested by MGA, to replicate real-world
conditions. Most vehicles in the fleet have a freely sliding belt
anchor. The proposed changes to FMVSS No. 213 (frontal sled test) set
forth in the November 2, 2020 NPRM also describe an inboard freely
sliding belt anchor. NHTSA is currently considering the comments to the
November 2, 2020 NPRM.
[[Page 39285]]
ii. Tethered vs. Non-Tethered CRS Installation
The NPRM proposed that the agency would attach the top tether of
the safety seat if a tether were provided and the owner's manual
instructs the caregiver to attach it.
Comments on whether the top tether should be attached during
testing were mixed. Some commenters suggested that testing without the
top tether would be representative of real-world CRS installation in
vehicles, as only about half of CRSs are installed using the top
tether. Other commenters recommended testing with the tether,
notwithstanding real-world use of the tether. Those commenters
generally supported use of informational and educational campaigns to
encourage tether use. Some commenters recommended testing both with and
without the top tether attached, as is done under the frontal impact
test of FMVSS No. 213.\207\
---------------------------------------------------------------------------
\207\ A more stringent head excursion requirement applies in the
test in which the tether is attached.
---------------------------------------------------------------------------
After considering the comments, NHTSA has decided to adopt the
proposed procedure to test forward-facing CRSs with the tether
attached, as test results showed that the use or non-use of the tether
does not produce significantly different results in the side impact
test environment. Each installation issue is discussed in turn below.
Comments Received
Many commenters recommended testing forward-facing CRSs without the
top tether attached. These included IIHS, UMTRI, Safekids, and SRN.
Several proponents of an untethered test pointed to studies showing
that tether use is low. IIHS discussed that observational surveys have
found that about half of all forward-facing CRSs are installed without
using the top tether \208\ and that the dynamic performance of CRSs
changes when the top tether is used.\209\ IIHS stated that because
tether non-use is common in the field, dynamic testing of CRSs should
include a no-tether condition to ensure any countermeasures developed
as part of the testing program would be effective at reducing injuries
under those circumstances. SRN stated that, if the tether makes little
difference in a near-side impact as had been asserted, it is necessary
to know more about the relative effectiveness between both installation
methods.\210\ SRN also wanted to know if the conclusion that the tether
has little effect in performance on a near-side impact was made based
on comparison testing done with tether anchors mounted in different
locations. SRN believed if there is truly no benefit provided by the
tether in a side impact, then it suggests adopting an untethered test.
---------------------------------------------------------------------------
\208\ Citing Cicchino & Jermakian 2014, Decina & Lococo 2007,
Eichelberger et al. 2014, Jermakian & Wells 2011, O'Neil et al.
2011.
\209\ Citing Kapoor et al. 2011, Lumley 1997, Menon & Ghati
2007.
\210\ SRN attributed this assertion to NHTSA but the statement
is not in the NPRM.
---------------------------------------------------------------------------
Some commenters suggested both a tethered and untethered test. Mr.
Hauschild suggested that for seats that have a tether, they should be
tested both with and without the tether. The commenter explained that
consumers are likely to use the CRS both ways, there may be different
kinematics of the dummy, and that many older vehicles still on the road
today may not have an upper anchor for the tether. Advocates
recommended that each CRS be required to pass the proposed testing
under all installation conditions permitted by the manufacturer for the
specific restraint.
In contrast to the above, CU, NTSB, Dorel, Britax, Graco, and JPMA
recommended testing with the tether attached. CU supported the use of
the top tether for testing all forward-facing CRSs, stating that the
tethers provide benefits in stabilizing and reducing head excursion in
frontal crashes, and that additional education and information should
be extended to encourage tether use. CU stated that its frontal test
protocol plans to test all forward-facing CRSs with top tethers
attached.
NTSB noted that the current correct usage rate for the top tether
is low--approximately 59 percent--in passenger vehicles, minivans,
light trucks, and sport utility vehicles. NTSB agreed that forward-
facing CRSs should be tested with the top tether, as recommended by the
manufacturer, but urged NHTSA to encourage both vehicle and CRS
manufacturers to increase the ease of use for top tethers. Dorel
supported the requirement that the top tether be attached during the
side impact test. Dorel stated that their data showed little difference
between struck near side ATD data between tethered and untethered
tests. Dorel added that the inclusion of untethered tests may not
provide additional meaningful information of the contact-side of the
test configuration and the resulting HIC scores.
Britax also supported the use of tethers during side impact
testing. Britax explained that, similar to the effect of deep side
wings and impact absorbing foam, the use of the tether enhances the
performance of the CRS during side impact by reducing the lateral
movement of the CRS, and this reduction in lateral movement assists in
containing the head within the CRS. Britax stated that requiring side
impact testing without the use of the tether would unreasonably deny
CRS manufacturers the benefits of tether technology, as opposed to
frontal impact testing of CRS (where the CRS is tested with and without
the tether), especially in the context of the unique lateral forces
generated in the side impact testing protocol. Britax concluded that
using the tether diminishes the potential for head injury.
Dorel and JPMA commented that they did not see any relationship
between HIC15 scores in paired tests of two CRS models installed using
CRAS (with tether) and with a Type I seat belt without the tether
attached.\211\ Graco stated that it always recommends the use of the
top tether when installing a forward-facing CRS. Graco added that it
does not believe there is any benefit in conducting the side impact
test both with and without the top tether.
---------------------------------------------------------------------------
\211\ NHTSA-2014-0012-0045, at pg. 6.
---------------------------------------------------------------------------
Agency Response
NHTSA performed two paired tests to evaluate the effect of the use
of the tether in the proposed side impact test. Two tests were
performed using the tether and two without the tether, as shown in
Table 20. Paired comparisons showed that the tests results (HIC and
chest deflection) with and without tether were not significantly
different (p>0.05).
[[Page 39286]]
Table 20--Comparison of CRS Performance in Tests of CRSs Installed With and Without Tether With the Q3s Dummy
--------------------------------------------------------------------------------------------------------------------------------------------------------
Chest deflection
VDB test No. CRS Orientation Attachment method HIC 15 [mm] Contact
--------------------------------------------------------------------------------------------------------------------------------------------------------
9630..................... Graco Comfort Sport... FF Convertible....... CRAS................. 640 21.1 Yes.
9631..................... Graco Comfort Sport... FF Convertible....... SB3PT&T.............. 580 18.6 Yes.
9633..................... Graco Comfort Sport... FF Convertible....... LA Only.............. 579 23.0 Yes.
9632..................... Graco Comfort Sport... FF Convertible....... SB3PT................ 649 19.1 Yes.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: SB3PT means 3-point belt, SB3PT&T means 3-point seat belt and tether, CRAS means the full child restraint anchorage system, LA Only means lower
anchorages of the child restraint anchorage system, and FF means forward-facing.
While tether use is extremely important in frontal crashes, in
near-side impacts the impact happens so quickly that the tether is
never engaged as the struck vehicle door intrudes into the seat
compartment. Due to this fact, and the results in the above table
showing that the use or non-use of the tether does not produce
significantly different results in the FMVSS No. 213a side impact test
environment, NHTSA will test forward-facing CRSs with the tether
attached.
Testing forward-facing CRSs with the tether attached will help
minimize any potential variability in test results due to setting up
the CRS while allowing a thorough evaluation in side impact of all
countermeasures provided by the CRS. Testing with and without tether,
as suggested by some commenters, would be unnecessarily burdensome as
the CRS would perform the same way in both tests. Since the performance
of the CRS when installed with or without the tether is not
significantly different, the test still ensures good performance in the
field even when tether use is low.
NHTSA notes that frontal sled tests of forward-facing CRSs with and
without tether have different performance as the use of a tether
results in improved injury values compared to the un-tethered tests.
Therefore, the need of testing in both conditions is necessary to
ensure their performance at two different stringency levels (i.e. head
excursions 813 mm for untethered test and 720 mm for tethered test) in
a frontal impact and ensure the safety of the CRS whether they are used
with or without the tether. While the top tether is used, if available,
during the side impact test procedure, in forward-facing CRSs, this
does not negate in any way the need to meet frontal requirements, both
with and without a tether.
Separate from this rulemaking, and as discussed further below, the
agency is currently working on potential improvements in tether use by
improving the marking of tether anchorages in vehicles.\212\ The
purpose of the marking is to increase consumer awareness of the
existence of tether anchorages and to facilitate consumer education
efforts.
---------------------------------------------------------------------------
\212\ In response to MAP-21, on January 23, 2015, NHTSA
published an NPRM to improve the usability of child restraint
anchorage systems, including standardizing and clarifying the
marking of tether anchorages (80 FR 3744). The RIN for the
rulemaking is 2127-AL20. It may be tracked in the Unified Agenda of
Regulatory and Deregulatory Actions (Agenda).
---------------------------------------------------------------------------
With respect to SRN's request to conduct tests with tethers mounted
in different locations, NHTSA selected the tether location on the SISA
based on the vehicle survey. Thus, it is highly representative of where
tether anchorages are located in vehicles. Since tether use or non-use
does not affect the performance of the CRS in the side impact test, the
agency believes the tether anchorage position will not influence the
performance of the CRS in the near-side impact environment selected for
FMVSS No. 213a. Thus, there is insufficient need to vary the location
of the anchorage in the test.
NTSB urged NHTSA to encourage both vehicle and CRS manufacturers to
increase the ease-of-use of top tethers. NHTSA's January 23, 2015 NPRM,
supra, proposed to amend FMVSS No. 225, ``Child restraint anchorage
systems,'' to improve the ease-of-use of the lower anchorages of child
restraint anchorage systems and the ease-of-use of tether
anchorages.\213\ The NPRM also proposed changes to FMVSS No. 213,
``Child restraint systems,'' to amend labeling and other requirements
to improve the ease-of-use of child restraint systems with a vehicle
anchorage system. The NPRM, issued in response to MAP-21, proposed
changes to Standards No. 213 and 225 to increase the correct use of
CRSs and child restraint anchorage systems and tether anchorages, with
the ultimate goal of reducing injuries and fatalities to restrained
children in motor vehicle crashes. NHTSA is continuing its work on this
rulemaking. The Fall 2021 Agenda notes that a final rule is planned for
March 2022.
---------------------------------------------------------------------------
\213\ 80 FR 3744 (Jan. 23, 2015).
---------------------------------------------------------------------------
iii. Distance Between Edge of Armrest and Edge of Seat
NHTSA proposed to specify in the test procedure that: (a) the CRS
would be centered on the sliding seat; and (b) that the front face of
the armrest on the door would be approximately 32 mm (about 1.25
inches) from the edge of the sliding seat towards the CRS at the time
the honeycomb interacts with the sliding seat structure. The prescribed
positions of the CRS (centered 300 mm (about 12 inches) from the edge
of the seat), and the armrest from the edge of the seat at the time the
door first interacts with the sliding seat structure, results in the
intruding door contacting wider CRSs earlier in the event than narrower
CRS. This contact of the intruding door earlier in the event to wider
CRSs results in a higher door impact velocity to the wider CRSs than to
narrower CRSs, which is an outcome representative of how different CRS
designs would perform in a specific vehicle in the real world. On the
other hand, NHTSA sought comment on whether the distance of the front
face of the armrest from the edge of the sliding seat at the time the
sliding seat starts to accelerate should be varied, such that all CRSs,
regardless of their width, would contact the impacting door at the same
time and with the same initial impact speed.
Comments Received
Comments were divided on this issue. Advocates recommended that the
distance between the CRS and the armrest be varied so that all CRSs,
regardless of their width, contact the impacting door at the same time
and with the same initial impact speed. Advocates stated that since the
premise
[[Page 39287]]
of the proposed testing is a component level test of the CRS (rather
than the CRS and a given vehicle combination, as in a full-scale test),
this change would ensure that all CRSs are subject to the same
conditions. The commenter believed that, given the wide range of
vehicle designs in which a CRS may be installed, artificially allowing
CRS design specifications, such as width, to influence the conditions
of the test would be inappropriate. Advocates suggested that NHTSA
establish a reasonable specified distance between the armrest and CRS
through a vehicle survey and by testing. The distance should represent
the most common and most appropriate distance for the test protocol,
while also providing the most stringent performance test for CRSs in
use today.
Dorel and JPMA commented that both approaches (keeping the distance
constant, or varying the distance to account for CRS width) each have
their unique conditions for introducing variability into the test,
which can drive CRS designs to be either wide or narrow to obtain the
best HIC measures. In support of this statement, Dorel provided a chart
comparing wide and narrow forward-facing (FF) CRSs installed with lower
anchorages of the CRAS and tethered, or with a belt and untethered.
These tests kept a constant distance of the front face of the armrest
from the edge of the seat at T0. In the tests, the wider CRS
had lower chest deflection results compared to the narrower CRS.\214\
---------------------------------------------------------------------------
\214\ NHTSA-2014-0012-0045, at pg. 6.
---------------------------------------------------------------------------
Dorel and JPMA believed that keeping the distance constant from the
front face of the armrest from the edge of the seat at the time the
sliding seat starts to accelerate, as proposed, could more accurately
reflect the consistent centering of the seating position between the
anchors to the door. Dorel and JPMA explained that this also naturally
aligns the center of the ATD with the center of the anchorages as well
and the ATD's distance to the door, and that it could drive CRS designs
to optimize on this condition, which would favor wider CRS designs.
Dorel added that the ATD forward head movement discussed in its comment
also enters more prominently in this condition. Dorel also commented
that the distance between the armrest and the CRS has the potential to
catch the door during the run up in acceleration phase very
differently, which could result in manufacturers developing narrower
CRSs as they would couple sooner in the event at a lower velocity.\215\
---------------------------------------------------------------------------
\215\ NHTSA understands this comment to be stating, in this
context, narrower CRSs would be in contact (couple) with the door/
armrest at a lower velocity than a wider one, as a wider one will
come in contact with the door/armrest sooner. While CRS to door/
armrest contact is happening, the velocity is decreasing so the
velocity that a narrower CRS experiences is lower than a wide one.
---------------------------------------------------------------------------
Dorel stated that the second option (distance varied) is a more
stable and repeatable condition, while option 1 (distance kept
constant) would introduce significant differences in testing
conditions. Dorel stated that the test should replicate conditions that
would drive CRS designs to yield meaningful and measurable
countermeasures to side impact injury mechanisms. Dorel concluded the
test must replicate real world conditions.
CU commented that the distance of the front face of the armrest
from the edge of the seat at the time the sliding seat starts to
accelerate should be kept constant. CU explained that, unlike in a
frontal crash, prior to which the front seatbacks can be moved to
provide additional spacing for a CRS, the distance to a door in an
actual vehicle will be fixed and cannot be altered. For this reason, CU
recommended leaving the door/armrest at a fixed distance. CU stated
that the width of CRSs would determine the point and velocity at
contact with that door, which would best simulate that same condition
in a real vehicle crash. In contrast, CU stated that a distance that is
altered to be equal for all CRSs would not simulate such real-world
conditions.
UMTRI favored the proposed test condition that all child restraints
be placed on the same pretest location on the bench, such that the
loading panel will contact wider child restraints before it would
contact narrow ones, as this represents a realistic vehicle situation.
UMTRI added that this may encourage child restraint manufacturers to
design narrower seats that would fit better in adjacent vehicle seating
positions.
Britax also recommended that the distance not be varied such that
all CRSs regardless of width contact the door within similar time and
velocity requirements. Britax explained that varying the distance
defeats the purpose and benefits of ``filling the gap'' and would
discourage the use of impact technologies that may result in CRSs that
enhance side impact energy management. Britax stated that this would
serve the contrary purpose of enabling CRS with less energy management
features to compare favorably with products that provide otherwise.
Graco also recommended using a constant CRS centerline position, as
proposed, regardless of the CRS base width. Graco requested NHTSA
consider adding a recommended method for confirming that the CRS is
centered, such as a visual indicator on the sliding seat to which the
CRS can be aligned, to increase repeatability of the test.
As discussed in a previous section, JPMA pointed out that there is
an inconsistency between the NPRM's specification for the door foam
thickness (51 mm) and the NHTSA drawing package specification (55 mm).
JPMA states that this difference in foam thickness specification is
significant because ``the NPRM includes set-up distances from the face
of the door panel to the face of honeycomb material and from the face
of the honeycomb material to the centerline of the sliding seat
[sic].'' JPMA explained that the thickness of the foam is thus an
important part of these set-up relationships and needs to be the same
in the final rule and the drawing package to help ensure consistent
test results between test facilities.
Agency Response
NHTSA believes that having a fixed distance from the front face of
the armrest to the edge of the seat towards the seat orientation
reference line (SORL) \216\ is the appropriate configuration to test
CRSs in a side impact. First, NHTSA believes that having a fixed
distance at the time of impact is more representative of the real-world
vehicle environment than using a varying distance. All CRSs will not be
impacted by the door at the same time, as vehicle designs vary and a
wider CRS will be impacted by the side door before a narrow CRS in the
same vehicle. Maintaining a fixed position of the armrest with respect
to the edge of the sliding seat at the time of initial impact of the
door assembly with the sliding seat will encourage manufacturers to
take into account the width of their safety seats in designing
countermeasures to meet FMVSS No. 213a, as the door will impact wider
CRSs at a higher velocity than narrower CRSs in the test, as it will in
the real world.
---------------------------------------------------------------------------
\216\ Seat orientation reference line means the horizontal line
through Point Z as illustrated in Figure 1 of the regulatory text
section of this final rule.
---------------------------------------------------------------------------
Second, a fixed distance works well in a representative generic
vehicle environment like the SISA. The FMVSS
[[Page 39288]]
No. 213 frontal impact sled test also uses a representative generic
vehicle environment for the test, and fixed distances are used to
assess the performance of the CRS in the frontal impact. In the frontal
test, the head and knee excursion limits are fixed with respect to
references on the frontal standard seat assembly regardless of the
initial head and knee position of the dummy. Fixing the excursion
limits presents a simplified test environment in which CRS
manufacturers can design thinner, thicker, or backless products that
position the head and knee of the test dummies at different fore/aft
positions and use countermeasures appropriate for their CRS to retain
the head and knees within the test envelop. Some CRSs will position the
head and knee closer to the excursion limits, others might choose to
design a thinner back to position the head and knees further away. The
fixed excursion limit does not vary with respect to the different CRS
design and provides certainty in the parameters of the test
environment. On the SISA, the fixed distance will provide manufacturers
the ability to decide whether to make narrow CRSs so they are tested at
a slightly lower speed or wider by adding different energy absorbing
technologies of their choice. Similarly, the window sill height of the
SISA, which represents a generic vehicle in the fleet, is fixed and
does not change based on the head position of the child dummy in a
particular CRS. CRS manufacturers may optimize their design that work
best with their side impact technologies.
As Dorel commented, both methods (fixed versus variable distance)
have different challenges and difficulties in setup. NHTSA believes
that varying the distance between the armrest and the edge of the
sliding seat would introduce more variability into the system as the
door fixture or the anchorage locations would have to be movable to
achieve a variable armrest/edge of sliding seat distance to achieve a
CRS to door impact at the same time in all CRSs. Thus, the reduced risk
of variability is an advantage of the fixed distance approach over the
alternative.
Graco requested NHTSA consider adding a recommended method for
confirming that the CRS is centered to increase test repeatability. As
described further in the report FMVSS No. 213 Side Impact Test
Evaluation and Revision,\217\ NHTSA used FARO arm measurements in its
sled tests to record and align the CRS and dummy with the SISA's SORL.
The agency's OVSC compliance test procedure will provide the method
that NHTSA will use to center the CRS in the SISA for compliance
testing.
---------------------------------------------------------------------------
\217\ Louden & Wietholter (2022).
---------------------------------------------------------------------------
JPMA pointed out that because of the inconsistency between the door
and arm rest foam thicknesses specifications in the drawing package and
the specifications in the NPRM,\218\ the set-up distance from the face
of the door panel to the face of honeycomb material is also
inconsistent from that specified in the NPRM. The NPRM specified that
the distance of the front face of the armrest on the door from the edge
of the bench seat at the time of contact of the door assembly with the
sliding seat of the side impact seat assembly (T0) (or setup
distance for this discussion) is 32 mm. We agree that the 32 mm setup
distance proposed in the NPRM regulatory text is incorrect because it
was computed using the manufacturer quoted nominal door foam thickness
and not the measured thickness (discussed in a previous section of this
final rule preamble). The correct setup distance computed using the
measured foam thickness is 38 mm.
---------------------------------------------------------------------------
\218\ This issue of the discrepancy in the door and armrest foam
thickness is discussed previously in the preamble in the section on
door characteristics.
---------------------------------------------------------------------------
NHTSA conducted side impact tests on the SISA to determine the
effect of variability in the setup distance on the performance
measures. NHTSA tested two CRS models (one in forward-facing
configuration and the other in rear-facing configuration) on the SISA
using 3 different setup distances. Table 22 shows that even with 12 to
14 mm variation in the setup distance the CV values of the performance
measures are very low and in the ``excellent'' repeatability range.
These results suggest that 12 to 14 mm variation in the setup distance
does not have significant effect on the performance measures.
Table 22--Test Results for Evaluating the Effect of Variation in the Distance Between the Front Face of the Armrest to the Front Face of the Honeycomb
--------------------------------------------------------------------------------------------------------------------------------------------------------
Setup distance Chest deflection
Test No. ATD CRS Orientation Restraint type [mm] HIC 15 [mm]
--------------------------------------------------------------------------------------------------------------------------------------------------------
10285................. Q3s Graco Size4Me 65.. RF Convertible.... LA Only........... 37 751 20.7
10116................. 33 778 23.5
10286................. 47 754 23.3
Average 761.2 22.53
STD Dev 12.25 1.27
CV % 2 6
10277................. Q3s Evenflo Tribute... FF Convertible.... CRAS.............. 34 712 21.3
10101................. 42 760 20.8
10278................. 46 732 22.0
Average 734.5 21.4
STD Dev 19.9 0.48
CV % 3 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: CRAS means the full child restraint anchorage system, LA Only means lower anchorages of the child restraint anchorage system, and FF means forward-
facing.
Based on these test results, the agency is revising the tolerance
for the setup distance from 2 mm to 6 mm.
Therefore, this final rule revises the specified distance of the front
face of the armrest on the door from the edge of the bench seat at the
time of contact of the door assembly with the sliding seat
(T0) to 38 6 mm. This measurement is consistent
with the final drawing package and addresses the errors in the NPRM and
proposed drawing package.
[[Page 39289]]
[GRAPHIC] [TIFF OMITTED] TR30JN22.016
e. Dummy Positioning
Arm Placement
NHTSA performed a series of tests for the NPRM to evaluate CRS
performance with the Q3s dummy, as discussed below. In the tests, NHTSA
observed, with regard to dummy positioning, that chest displacements of
the Q3s, tested in the same CRS model, were higher when the dummy's arm
was positioned in line with the thorax than when the arm was rotated
upward so as to expose the thorax to direct contact with the intruding
door. NHTSA proposed an arm position at 25 degrees with respect to the
thorax, and noted that the Q3s dummy's shoulder contains a detent to
aid in this positioning. NHTSA requested comment on this arm position.
Comments Received
We received many comments supportive of arm positioning. Dorel
supported the inclusion of an arm positioning specification, stating
that it provides additional consistency of setup conditions for
repeatability and reproducibility. Graco stated that it has determined
that the IR-TRACC measurement (for chest deflection) can change
significantly as a function of arm placement. Graco recommended
improving the variation in the Q3s chest deflection measurements. It
suggested that a large range (10 mm) it found in chest deflection was
due to inconsistent arm placement, and that a more defined set-up
practice may reduce these differences. Similarly, TRL commented that
the pre-test position of the arm can have a significant effect on the
dummy chest deflection readings, and that care should be taken to
install the dummy as described in the installation procedure of
Standard No. 213a to ensure consistent test results. Advocates stated
that the agency should establish an arm position which correlates best
with the real-world positioning of children in CRS and injury
frequencies observed in available crash data.
Agency Response
The final test procedure specifies that each of the dummy's arms be
rotated downwards in the plane parallel to the dummy's midsagittal
plane until the arm is engaged on the detent that positions the arm at
a 25 degree angle with respect to the thorax, as proposed in the NPRM.
This final rule specifies that the agency will position the lower
portion of the Q3s arm to be as aligned as possible to the upper arm
(25-degrees) that is determined by the detent. If there is interference
of the arm with the CRS or dummy body, the lower arm can be slightly
bent. VRTC achieved good repeatability with this test procedure it
developed.\219\
---------------------------------------------------------------------------
\219\ See Louden & Wietholter (2022) for more details.
---------------------------------------------------------------------------
In response to Advocates, NHTSA is not aware of data that
correlates arm position with injury data. However, we believe the arm
in the down position would not be an unrealistic positioning of the
arm.
Leg Placement
In the NPRM, NHTSA noted that, when testing with the Q3s dummy in a
rear-facing CRS, the legs of the dummy were extended upwards and
rotated down until they were in contact with the SISA seat back. NHTSA
requested comment on the position of the Q3s dummy legs when testing
rear-facing CRSs with that dummy.
Comment Received
Graco requested that NHTSA specify whether to remove the knee stop
bolts when using the Q3s in a rear-facing seat. It explained that
currently, testing practices vary between test facilities and should be
standardized for consistency. Graco stated no structural damage
occurred in its tests when it did not remove the knee stop.
Agency Response
NHTSA will not remove the knee stop bolts when using the Q3s dummy
in a rear-facing seat. In the November 2, 2020 NPRM to update the
frontal sled test in FMVSS No. 213, NHTSA proposed a procedure calling
for the removal of the knee stop in the Hybrid III (HIII) 3-year-old
dummy when used in rear-facing CRSs. In tests of rear-facing CRSs with
the HIII-3-year-old dummy, the stiff seated pelvis of the dummy causes
the dummy's legs to brace against the seat back, resulting in a forward
load on the CRS that could
[[Page 39290]]
push the CRS forward. The agency sought to remove the knee-stops to
prevent such bracing of the HIII-3-year-old dummy's legs against the
seat back.
In contrast, the Q3s dummy has more flexibility in the pelvic joint
than the HIII dummy, which allows the positioning of the legs of the
Q3s without the removal of the knee stop. This final rule specifies
that each of the dummy's legs be rotated downwards in the plane
parallel to the dummy's midsagittal plane until the limb contacts a
surface of the child restraint or the SISA. f. Dummy selection
The January 2014 NPRM proposed using the Q3s dummy and the CRABI
12-month-old dummy to test CRSs under the side impact requirements.
Specifically, the NPRM proposed using the Q3s to test CRSs designed for
children weighing 10 kg to 18.1 kg (22 lb to 40 lb), and using the
CRABI 12-month-old to test CRSs designed for children weighing up to 10
kg (22 lb). These weight categories were designed to be consistent with
the criteria used in the current FMVSS No. 213 in determining the test
dummies that are used to test child restraints to the standard's
frontal test requirements.
In NHTSA's November 2, 2020 NPRM proposing updates to FMVSS No.
213, NHTSA proposed changes to those criteria.\220\ The November 2020
NPRM proposed that the Hybrid III 3-year-old test dummy used in FMVSS
No. 213 would only be used to test CRSs designed for children weighing
13.6 to 18.1 kg (30-40 lb), and that the 12-month-old CRABI would be
used to test CRSs designed for children weighing up to 13.6 kg (30 lb).
The agency proposed the change after tentatively concluding that the 3-
year-old dummy does not adequately fit CRSs rated for children weighing
10 kg to 13.6 kg (22 to 30 lb), and does not properly represent the
children for whom the restraints are intended. The November 2020
frontal upgrade NPRM noted that the 2014 side impact NPRM sought to
align the weight cut offs for dummy selection with that of FMVSS No.
213. The November 2020 NPRM requested comment on using the Q3s 3-year-
old dummy to test CRSs designed for children weighing 13.6 to 18.1 kg
(30-40 lb) in the side impact test and using the CRABI-12MO to test
CRSs designed for children weighing up to 13.6 kg (30 lb).\221\
---------------------------------------------------------------------------
\220\ 85 FR 69388, supra. See Section IX, 85 FR 69429.
\221\ 85 FR at 69436.
---------------------------------------------------------------------------
Comments Received
In response to the 2014 side impact NPRM, CU commented that, based
on its understanding of the proposed rule (specifically S7.1(b) of
proposed FMVSS No. 213a), the agency would use the Q3s to test infant
seats. CU disagreed with this proposal, stating that evaluating the
side impact performance of infant seats using the Q3s dummy is likely
to misrepresent those seats' protective features, as the Q3s is
technically too tall for those seats. CU was concerned that, with the
dummy's head extended far above the seat's shell, side impact
protection within the shell will not ``register'' in the dummy's
measured head dynamics. Based on its limited tests, CU observed that
the Q3s head exceeding the shell height may result in decreased HIC
values, thereby ``overrating'' the seat's side impact protection. CU
stated that this potential to achieve lower HIC numbers could influence
manufacturers to ``design for the test'' rather than for real-world
child and CRS interactions, which could have negative implications. For
instance, manufacturers could reduce shell heights or containment
attributes, which could improve side impact regulatory test results but
potentially reduce performance in real-world crashes.
CU stated that NHTSA may not have seen this interaction issue with
the Q3s and infant seats, as the test development results discussed in
the NPRM indicated that the rear-facing seats tested with the Q3s were
all convertible seats, not infant seats. Infant seats were only tested
in NHTSA's tests with the CRABI 12-month-old dummy, even though the
current child seat market includes infant seats that would meet the
NPRM test thresholds requiring the Q3s (S7.1). The commenter did not
believe the side impact pulse produces a level of energy that will
result in a high number of structural failures and stated that, given
the Q3s dummy size and limited potential for assessing structural
failure, the Q3s dummy has little value for assessing side impact
protection in infant seats. CU said that, in its own test methodology,
it uses larger-weight dummies that may exceed shell accommodations to
evaluate the structural integrity of seats, rather than injury metrics.
CU believes an alternative side impact instrumented dummy should be
considered for infant seat testing that would more appropriately
represent real-world usage and provide biofidelic injury values.
Similarly, UPPAbaby recommended against using the Q3s dummy to test
rear-facing infant seats, because, it stated, ``the head of the Q3s
exceeds the limit to which we recommend a child be positioned in our
seat.''
Comments to the November 2, 2020 frontal upgrade NPRM supported the
proposed dummy selection weight and height criteria and the alignment
of the applicable dummy selection for both frontal and side impact
tests. Four commenters (IMMI, Salem-Keiser, Graco and Volvo) supported
the proposed dummy selection changes. Two commenters (Safe Ride News
and Graco) expressed support for having the same dummy selection
criteria in both standards. Consumer Reports \222\ (CR) reiterated its
comment to the side impact NPRM (summarized above) where it argued that
the CRABI-12 MO should be used to evaluate infant CRSs with recommended
weights over 30 pounds as the 3-year-old dummies are too big for these
CRSs.
---------------------------------------------------------------------------
\222\ Consumer Union is the Policy and Action Division of
Consumer Reports.
---------------------------------------------------------------------------
Agency Response
To better align the dummy selection for the side impact test with
the size and weight of children typically restrained in the CRS, this
final rule adopts the use of the CRABI-12-month-old to test CRSs
designed for children weighing up to 13.6 kg (30 lb) and that of the
Q3s (3-year-old dummy) to test CRSs designed for children weighing 13.6
to 18.1 kg (30 to 40 lb). These specifications are aligned with the
proposed ranges for the FMVSS No. 213 frontal impact test in the
November 2, 2020 NPRM. Table 23 below shows the ATD use adopted for the
side impact test based on the child weight and height recommendation
for the CRS.
Table 23--Amendments to ATD Use Based on Manufacturer's Weight and
Height Recommendations
[Adopted by this final rule]
------------------------------------------------------------------------
Are compliance tested by NHTSA
CRS recommended for use by children of with these ATDs (subparts refer
these weights and heights-- to 49 CFR part 572)
------------------------------------------------------------------------
5 kg (11 lb) to 13.6 kg (30 lb) in CRABI-12-Month-Old (subpart R).
weight; 650 mm (25.5 inches) to 870 mm
(34.3 inches) in height.
[[Page 39291]]
Weight 13.6 kg (30 lb) to 18.1 kg (40 Q3s 3-Year-Old Child Dummy
lb); Height 870 mm (34.3 inches) to (subpart W).
1100 mm (43.3 inches).
------------------------------------------------------------------------
The changes in weight and height dummy selection criteria address
Consumers Union (Consumer Reports) and UPPAbaby's concerns that testing
infant seats with the Q3s dummy would position the dummy's head higher
than the manufacturer's recommended use of the restraint. In the
November 2, 2020 frontal upgrade NPRM, NHTSA explained that the current
CRS market encompasses infant carrier models recommended for children
weighing up to 10 kg (22 lb), 13.6 kg (30 lb), 15.8 kg (35 lb), and
18.1 kg (40 lb) and with child height limits ranging from 736 mm (29
inches) to 889 mm (35 inches). Under current FMVSS No. 213 and the
FMVSS No. 213a NPRM, these infant carriers would be subject to testing
with the HIII-3-year-old or Q3s (35 lb) dummy. However, as commenters
have pointed out, the HIII-3-year-old or the Q3s dummy do not fit
easily in infant carriers and have limitations as test devices to
evaluate the restraints.
Given the purpose of infant carriers, NHTSA concludes there is not
a safety need warranting a redesign to accommodate a 3-year-old dummy.
Current infant carriers are convenient to use with infants and are
popular with parents and other caregivers. The availability and ease-
of-use of current carriers may result in more infants riding
restrained, and rear-facing, than if the carriers were heavier, bulkier
and more expensive. NHTSA does not believe that the infant carriers are
used frequently for children weighing more than 13.6 kg (30 lb).
Information from child passenger safety technicians involved in child
restraint system checks indicates that infants usually outgrow infant
carriers because of reaching the height limit of the carrier, rather
than the weight limit. Further, as an infant reaches a 13.6 kg (30 lb)
weight,\223\ the combined weight of the infant and the infant carrier
becomes too heavy for a caregiver to pull out of the vehicle easily and
carry around by a handle. Therefore, caregivers typically switch to a
convertible or all-in one CRS as the child weight increases. A 13.6 kg
(30 lb) maximum weight threshold for infant carriers would accommodate
all 1-year-old children (the average 97th percentile 1-year-old weighs
27.2 lb (12.3 kg)).
---------------------------------------------------------------------------
\223\ An average 97th percentile 1-year-old is 12.3 kg (27.2
lb).
---------------------------------------------------------------------------
The changes on dummy selection criteria would still allow a
manufacturer to continue marketing its infant carrier for children
weighing more than 13.6 kg (30 lb), but we anticipate manufacturers
will not exceed the 13.6 kg (30 lb) weight threshold. Practically
speaking, children weighing more than 30 lb \224\ would be too old (no
longer an infant), heavy and tall to easily fit an infant carrier.
Nonetheless, if an infant carrier were recommended for children
weighing more than 13.6 kg (30 lb), NHTSA would test it with the 3-
year-old child dummy, and the manufacturer would be required to certify
that the CRS can meet the performance requirements of the FMVSS when
tested with the 3-year-old dummy.
---------------------------------------------------------------------------
\224\ An average 97th percentile 2-year-old is 15.3 kg (33.9
lb).
---------------------------------------------------------------------------
g. Miscellaneous Comments on the Test Procedure, Including Test Setup,
Sled Instrumentation, and Data Processing
For the NPRM, NHTSA placed a technical report, ``Child Restraint
Side Impact Test Procedure Development'' (2013), in the docket which
detailed NHTSA's testing with regards to the sled test. MGA and Graco
provided feedback on or requested clarification of different aspects of
the proposed test procedure.\225\
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\225\ The test procedure set forth in FMVSS No. 213a describes
the procedure NHTSA will use to conduct its compliance test. NHTSA's
Office of Vehicle Safety Compliance (OVSC) issues a Test Procedure
(TP) that provides more detailed information to its contractors
about running the compliance test. However, under the Safety Act,
manufacturers self-certify the compliance of their vehicles and
equipment with all applicable FMVSSs; they are not required by NHTSA
to conduct the test described in the FMVSS or TP to certify the
compliance of their products with the FMVSS. Instead, manufacturers
must ensure that, when NHTSA conducts the test described in the
standard and TP, the vehicle or equipment will meet the requirements
in the standards. While not required to do so, manufacturers
generally self-certify their products by using the test procedures
set forth in the FMVSSs and TPs. This is because running the same
test better ensures that the vehicle or equipment will perform in a
manner that meets the FMVSSs requirements when tested by NHTSA,
compared to a different test the manufacturer had used to make the
certification.
---------------------------------------------------------------------------
High-Speed Camera Views
MGA was concerned that no high-speed camera views were specified in
FMVSS No. 213a. MGA stated that off-board cameras will require fewer
structural elements to hold the cameras in place, which would aid in
the ease of construction for new equipment. In response, NHTSA is
providing guidance for use of high-speed cameras. NHTSA's technical
report, ``FMVSS No. 213 Side Impact Test Evaluation and Revision,''
\226\ details VRTC's high-speed camera views that it used in the
development of the test protocol.\227\ The compliance test procedures
developed by NHTSA's Office of Vehicle Safety Compliance (OVSC) will
describe the camera positions that OVSC will use in its testing, which
test facilities can use in developing their FMVSS No. 213a test
protocols.
---------------------------------------------------------------------------
\226\ Louden & Wietholter (2022), supra.
\227\ VRTC's onboard camera fixtures are not part of the drawing
package, as test facilities are not required to use cameras. If they
use cameras, they may choose to use onboard or off-board cameras
with the same views (or any other position of their choosing).
---------------------------------------------------------------------------
Belt Tension
MGA commented that the internal harness tension in FMVSS No. 213a
is specified as ``not less than 9 N,'' while in FMVSS No. 213 it is
specified as ``Tighten the belts until a 9 N force applied to the
webbing at the top of each dummy shoulder and to the pelvic webbing 50
mm on either side of the torso midsagittal plane pulls the webbing 7 mm
from the dummy.''
NHTSA concurs that FMVSS No. 213a should specify an upper limit for
tensioning internal harnesses, to have consistency in testing.
Therefore, NHTSA is also including an upper limit to this internal
harness tension. This final rule adopts a provision in FMVSS No. 213a
that specifies the internal harness tension as ``not less than 9 N but
not more than 18 N.'' This wording would be consistent with the FMVSS
No. 213 instruction discussed in the November 2, 2020 NPRM.
MGA also commented that, according to FMVSS No. 213a, booster seats
would be tested with a Type 2 seat belt assembly that has the lap belt
tensioned
[[Page 39292]]
to 12 to 15 lb. MGA stated that the current FMVSS No. 213 requires a
tension of 2 to 4 lb in both the lap and shoulder belt portion of the
assembly. MGA suggested that for FMVSS No. 213a, this tension is
revised to be a constant 2 to 4 lb. NHTSA agrees with MGA's suggestion.
NHTSA had updated the lap belt tensions when installing booster seats
in a 2012 final rule (77 FR 11625) to 2 to 4 lb but had inadvertently
used the previous specification of 12 to 15 lb in the NPRM preceding
this final rule. We believe the belt tension should be consistent with
the current practices, and, therefore, we revised the tension
accordingly.\228\
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\228\ NHTSA does not anticipate booster seats will be produced
that are subject to FMVSS No. 213a. First, NHTSA has proposed a
requirement that boosters must be labeled as not suitable for
children weighing less than 18.1 kg (40 lb) (85 FR 69388, supra).
Second, even in the absence of the proposed prohibition on labeling
boosters for children under 40 lb, it is unlikely booster seats can
meet the requirements of FMVSS No. 213a, so manufacturers will
likely label them to fall outside of the applicability of the side
impact standard.
---------------------------------------------------------------------------
Instrumentation and Data Collection
With regards to instrumentation and data collection, MGA commented
that the NPRM materials specify both integrated accelerometer readings
and a velocity trap for producing relative velocity readings between
the sliding seat and intruding door. MGA asked which of these is
considered the primary means of measurement, and which one is
considered secondary.
In response, because of modifications to the test buck design,
NHTSA has removed the velocity trap. The integration of accelerometers
is the primary source for relative velocity readings, as described in
more detail in the technical report, ``FMVSS No. 213 Side Impact Test
Evaluation and Revision.'' \229\
---------------------------------------------------------------------------
\229\ Louden & Wietholter (2022).
---------------------------------------------------------------------------
MGA also requested additional clarification with regards to the
measurement of the acceleration and velocity of the intruding door. MGA
asked, since the intruding door and sliding seat assembly are moving at
a 10-degree angle, can a traditional sled carriage accelerometer
(mounted at 0 degrees on the sled carriage frame) be used to measure
the intruding door acceleration, or does it need to be mounted at a 10-
degree angle? MGA also asked if this accelerometer should be mounted
near the CG of the sled platform or on the intruding door.
In response, the acceleration of the intruding door and the sliding
seat perpendicular to the ``seat orientation reference line'' (SORL)
\230\ of the sliding seat is used to determine the relative velocity
between the door assembly and the sliding seat. If the accelerometer is
mounted at 0-degrees on the sled carriage frame, the acceleration
measured is multiplied by cosine (10-degrees) to obtain the
acceleration perpendicular to the SORL of the sliding seat. The report,
``FMVSS No. 213 Side Impact Test Evaluation and Revision,'' supra,
details these calculations. The drawing package for the SISA, found in
the docket for this final rule, provides information on the location of
the accelerometers on the sled carriage with the door assembly and on
the sliding seat.
---------------------------------------------------------------------------
\230\ Seat orientation reference line means ``the horizontal
line through Point Z as illustrated in Figure 1A'' of FMVSS No. 213.
49 CFR 571.213, S4 Definitions.
---------------------------------------------------------------------------
Also with regard to the accelerometers, MGA commented that dampened
accelerometers are a good choice to read the sliding seat acceleration
and velocity due to excessive vibration caused from impact with the
honeycomb. However, MGA stated that SAE J211 (regarding instrumentation
for impact tests, discussed further below) does not have provisions for
dampened accelerometers. MGA stated that NHTSA will need to specify a
dampening ratio, as the accelerometers used for NHTSA research have a
different dampening ratio than the accelerometers used in MGA
evaluation testing. MGA asked how the data would be processed for the
dampened accelerometer, and would a CFC60 be used for acceleration data
and CFC180 for velocity data like for traditional sled accelerometers?
MGA also asked if there was a specific location on the sliding seat
where the accelerometer should be located.
In response, NHTSA has updated the SISA, as discussed above, which
has reduced excessive vibrations, and therefore dampened accelerometers
are not used. The locations of the non-dampened accelerometers can be
found in the final drawing package and the ``FMVSS No. 213 Side Impact
Test Evaluation and Revision'' report.\231\
---------------------------------------------------------------------------
\231\ Louden & Wietholter (2022).
---------------------------------------------------------------------------
Updating references to SAE Recommended Practice J211. The November
2014 NPRM on FMVSS No. 213a proposed to reference SAE Recommended
Practice J211, ``Instrumentation for Impact Test,'' revised in June
1980, and proposed that all instrumentation and data reduction conform
to J211 (1980). The reference to the June 1980 version was consistent
with the current test specifications of FMVSS No. 213. MGA expressed
concern over the use of J211 from 1980. MGA stated that J211 is a very
commonly used test standard and is updated frequently, and that the it
has been updated numerous times since 1980. MGA suggested incorporating
J211 from 2014 to reflect the latest revision.
In the November 2, 2020 proposed frontal upgrade NPRM, supra, NHTSA
proposed updating the reference to SAE Recommended Practice J211(1980)
to SAE Recommended Practice J211/1 (1995). The 1995 version was
proposed because FMVSS No. 208, ``Occupant crash protection,''
currently refers to the 1995 revision, and the 1995 version of SAE
J211/1 is consistent with the current requirements for instrumentation
and data processing in FMVSS No. 213. FMVSS No. 208 was important to
this decision because its specifications are used in Standard No. 213
regarding testing of built-in child restraint systems. Standard No. 213
has a procedure in which the agency can test a built-in child restraint
using an FMVSS No. 208 full vehicle crash test. Accordingly, using the
same Recommended Practice J211/1 (1995) in FMVSS No. 213 facilitates
the processing of test results when combining a test of built-in child
restraints with an FMVSS No. 208 test.
In this final rule, NHTSA has decided to update the reference to
SAE Recommended Practice J211/1 (1995) to keep consistency between
FMVSS No. 213 and 213a. NHTSA is not adopting the 2014 version of J211
because Standard No. 208 uses the 1995 version, and consistency between
FMVSS No. 208 and FMVSS No. 213 is important for testing built-in child
restraints.
Measuring Head Contact of the CRABI
MGA suggested that additional wording would be helpful for
measuring the 12-month-old CRABI dummy head contact criterion pass/fail
event. MGA stated that common testing practices include chalk or paint
on the ATD head or door, or a conductive contact tape with a recorded
signal. MGA added that paint and chalk are a relatively inexpensive and
accurate way to look at the marks left during the test, but can produce
error if not carefully applied. The commenter recommended that a test
procedure with a common way of marking should be developed. MGA also
stated that contact tape provides a more definitive event but has
drawbacks including complexity in setup, and a chance for losing data
since it is a recorded signal.
[[Page 39293]]
Graco's comment described 42 sled tests, conducted in different
labs, using the 12-month-old CRABI dummy to measure head contact with
the door structure. Graco's results showed that only one of the six
CRSs evaluated produced conflicting head contact performance across the
different test facilities. Graco provided video stills to show the non-
repeatable head contact result at the different test facilities, where
the camera angle made determination of head contact difficult. Graco
suggested that the use of common camera angles and non-video contact
methods may help confirm whether contact has occurred. Graco added that
the common camera view it would recommend is a top view, approximately
3 feet above the door sill, and that this worked well for both forward-
and rear-facing tests and could allow for a consistent determination of
the head position from the door foam.
Graco also commented on the non-video options considered in the
NPRM, stating that with the contact paint there is possible confusion
in determining if paint corresponds to the current test or a previous
test. Graco also expressed concern with instrumented contact tape, as
the commenter believed that method has not been proven to be
repeatable. Graco stated that further development of these options
could allow for a more concrete determination beyond video analysis
only.
In response to these comments, NHTSA tested several methods to
evaluate head containment to address commenters' concerns about
different test methodologies. The methodologies included:
Wire mesh with foil contact tape. This method consists of
wrapping the CRABI 12-MO dummy's head in a copper wire mesh sleeve and
metal foil contact tape applied to the door with double sided duct tape
to ensure adhesion to the door as CRS impacts into it. A 1 Volt Voltage
is applied to the foil contact tape causing a short circuit when the
copper wire mesh makes contact. This results in a Voltage vs. Time
plot.
Camera View. Camera coverage is aligned with the edge of
the wall to visually witness head to door contact. For forward-facing
CRSs NHTSA used a front tight view of the head and door area, and for
rear-facing CRSs a tight view from the rear of the seat assembly. The
camera placement used during NHTSA's testing is detailed in OVSC's test
procedures so that test facilities can replicate the same camera views.
Grease Paint. Grease paint was used on the dummy's head to
detect head-to-door contact by paint transfer to the door.
To share information and possibly further the enhancement of test
protocols in the future, NHTSA discusses the agency's experience with
these tests in the ``FMVSS No. 213 Side Impact Test Evaluation and
Revision'' report.\232\ Each method has its strengths and limits. Mesh
and contact tape may have set up or equipment failures, and camera
views do not always capture the head-to-door contact even when aligned
to the door, as some CRSs require a carry-handle to be used in its
``carrying'' position, which blocks the view of the head and the door.
Alternatively, grease paint is sometimes transferred with very light
touches. NHTSA's compliance TP will describe how NHTSA/OVSC instructs
its contractors to conduct and evaluate head contact in compliance
testing. However, NHTSA reiterates it is each manufacturer's
responsibility to certify the compliance of its CRSs with FMVSS No.
213a, and that manufacturers may use means or tools other than those
described in the report or the OVSC TP to determine whether there was
dummy head contact.
---------------------------------------------------------------------------
\232\ Louden & Wietholter (2022).
---------------------------------------------------------------------------
h. Additional Changes
Section 9.2(c) of the proposed regulatory text referred to
a 178 Newton (N) force that would be applied to the dummy's crotch and
thorax using a flat square surface with an area of 2,580 square
millimeters. In the final rule, this step has been changed, as applying
this force to the Q3s dummy may inadvertently cause the dummy's skin to
get tucked in the pelvis.
Section 6.1.2 (a)(1) of the proposed rule indicated a
tension for the tether as not less than 53.5 N and not more than 67 N.
During the tests of the FMVSS No. 213 frontal upgrade program (which
uses the same seat assembly design as this final rule for side impact),
NHTSA found that in some cases the tethers could not be tightened to
the proposed tension range because the seat assembly has a thinner seat
back cushion (2 inches) than the current FMVSS No. 213 seat. This final
rule adopts a tension range of not less than 45 N and not more than
53.5 N. This lower range in tension values for the tether are based on
tether tensions achieved in the tests conducted at VRTC and therefore
are practicable.
The application section (S3) was changed to clarify, but
not change, its meaning. The revised wording is as follows:
S3. Application. This standard applies to add-on child restraint
systems that are either recommended for use by children in a weight
range that includes weights up to 18 kilograms (40 pounds) regardless
of height, or by children in a height range that includes heights up to
1100 millimeters regardless of weight, except for car beds and
harnesses.
S5(a) and S6.1.1(e) were slightly reworded to make clearer
that each child restraint system is required to meet the performance
requirements at each of the restraint's seat back angle adjustment
positions and restraint belt routing positions, in both the forward and
rearward facing installation, as recommended by the manufacturer's
instructions.
Added Section 5.1.6 to indicate the means of installation
for which child restraint systems are required to meet the
requirements, which include the Type II, Type II plus tether, Lower
anchorages, and Lower anchorages plus tether as applicable to the
different CRS types.
S6.1.1(a)(2)(c) was slightly edited to include the word
``any'' in the requirement before the words pulse and velocity. Here
and elsewhere, the word any, used in connection with a range of values
or set of items in the requirements, conditions, and procedures of the
standard, means the totality of the items or values, any one of which
may be selected by the Administration for testing, except where clearly
specified otherwise. See Section 571.4.
Sections 6.1.2(a)(1) through (3) were slightly edited for
clarity stating that no supplemental devices are used to install the
CRS when testing to FMVSS No. 213a. In addition, section 5.1.6 was
added to specify that CRSs must meet the requirements of the standard
when installed solely by each of the listed installation methods. These
changes are consistent with FMVSS No. 213 where CRSs are required to
meet the standard solely by the installation methods in S5.3.2 and that
no supplemental devices (i.e. load leg) will not be used.
S7.1 and S6.1.2(b) wording was slightly modified to be
consistent with S7.1 (a) and (b).
VIII. Performance Requirements
NHTSA proposed using the Q3s and CRABI 12-month-old test dummies to
test the conformance of CRSs to the side impact requirements. With the
Q3s, we proposed to require CRSs to meet performance requirements such
that the head injury criterion (HIC) over a 15 millisecond (ms)
timeframe was less than 570, and the chest displacement injury
assessment reference value (IARV) was less than 23 mm. With the CRABI
12-month-old, we proposed to measure whether there was head-to-
[[Page 39294]]
door contact only, as the CRABI 12-month-old is a frontal test dummy
and was not developed to provide accurate data about the severity of
injuries in side impacts.
NHTSA is finalizing a test procedure that utilizes the Q3s and the
CRABI 12-month-old dummies and the proposed injury and other
performance criteria. After careful consideration of the comments and
other information, including data from additional testing with the Q3s,
NHTSA determined that the Q3s effectively replicates a child in a side
impact and provides a reliable assessment of injury measures in the
side impact environment. In addition, although there is currently no
infant-sized dummy available specifically for side impact testing,
NHTSA concludes that the CRABI 12-month-old is a suitable instrument
for assessing the ability of a CRS to prevent head-to-door contact and
is an acceptable tool for evaluating important aspects of CRS
performance in side crashes.
a. Q3s
The Q3s is built on the platform of the standard Q3 dummy series
(the Q-series are frontal ATDs used in Europe), but the Q3s has
enhanced lateral biofidelity, durability, and additional
instrumentation for specialized use in side impact
testing.233 234 For instrumentation, the Q3s has three uni-
axial accelerometers at the head center of gravity (CG) and an InfraRed
Telescoping Rod for Assessment of Chest Compression (IR-TRACC) \235\ in
the thorax for measuring lateral chest deflection. The Q3s also has a
deformable shoulder with shoulder deflection measurement capabilities,
arms with improved flesh characteristics, a laterally compliant chest,
and a pelvis with improved upper leg flesh, floating hip cups, and a
pubic load transducer.\236\ Specifications for the Q3s were adopted
into NHTSA's regulation for anthropomorphic test devices (49 CFR part
572) on November 3, 2020 (85 FR 69898).\237\
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\233\ The anthropometry of the Q3 (and the side impact
adaptation Q3s) is based on the Child Anthropometry Database
(CANDAT) for a 3-year-old child compiled by the Netherlands
Organization for Applied Scientific Research (TNO). CANDAT includes
various characteristic dimensions and weights of children of
different ages obtained from different regions in the world
including United States, Europe, and Japan.
\234\ NHTSA evaluated the Q3 dummy and found that the Q3 dummy
did not have adequate biofidelity in lateral impact, in contrast to
the Q3s dummy, which was designed for side impacts.
\235\ The IR-TRACC is a deformation measurement tool that
consists of an infrared LED emitter and an infrared phototransistor
detector. The emitter and detector are enclosed at each end of a
telescoping tube. The chest deformation is determined from the
irradiance measured by the detector, which is inversely proportional
to the distance of the detector from the emitter.
\236\ Carlson, M., Burleigh, M., Barnes, A., Waagmeester, K.,
van Ratingen, M. ``Q3s 3 Year Old Side Impact Dummy Development,''
20th International Conference on the Enhanced Safety of Vehicles,
Paper No. 07-0205, 2007. http://www-nrd.nhtsa.dot.gov/pdf/esv/esv20/07-0205-O.pdf. Last accessed on June 11, 2012.
\237\ A few specifications were corrected in a response to a
petition for reconsideration. 86 FR 66214, November 22, 2021. The
document corrected a few drawings in the drawing package for the
dummy and some provisions in the user's manual.
---------------------------------------------------------------------------
NHTSA cited several reasons in the 2014 NPRM for selecting the Q3s
for testing in the side impact test procedure, including the ATD's
commercial availability, its enhanced biofidelity and instrumentation
capabilities, and its durability. The injury criteria proposed for use
with the Q3s dummy included a maximum HIC value of 570 measured in a 15
ms timeframe and a chest displacement IARV of 23 mm. NHTSA did not
believe there was reason to propose a performance criterion for testing
with the Q3s that would prohibit head contact with the intruding door,
because testing in development of the NPRM demonstrated that peak HIC
values occurred prior to the head contacting the intruding door. In
other words, the risk of head injury from head-to-door contact was
lower than the risk from peak acceleration, so measuring the peak HIC
value from head-to-door contact would not further the assessment of
compliance.
Comments on the proposed use of the Q3s were mixed, with some
commenters expressing concerns about dummy sourcing and biofidelity,
and other commenters supporting the use of the Q3s. NHTSA received some
comments in support of the proposed performance requirements for the
Q3s, but none on the specific HIC or chest deflection values proposed
in the NPRM. Many commenters requested that the agency include a head
containment requirement for the Q3s. As discussed below in this
section, this final rule adopts the use of the Q3s dummy in the FMVSS
No. 213a side impact test, along with the performance criteria proposed
in the NPRM. The agency's November 3, 2020, final rule incorporating
the Q3s test dummy into 49 CFR part 572, discusses technical details
about the Q3s.
1. Q3s Sourcing
As discussed in the November 3, 2020 final rule and further below,
the sourcing and biofidelity issues associated with the Q3s have been
addressed. Humanetics Innovative Solutions Inc. (HIS), the ATD
supplier, only had minor drawing corrections to the November 3, 2020
final rule adopting the Q3s, and these corrections have been adopted in
the November 22, 2021 final rule responding to the petition for
reconsideration. With the final corrections adopted, NHTSA is confident
that HIS will be able to deliver the Q3s within specification. When
NHTSA published its 2013 NPRM proposing to incorporate the Q3s test
dummy into 49 CFR part 572 (78 FR 69944; November 21, 2013), the Q3s
was a proprietary product owned by HIS, and HIS was the only source
from which to obtain the Q3s. By mid-2014, after the publication of the
FMVSS No. 213a side impact NPRM, HIS began delivering Q3s dummies to
end-users that included NHTSA, CRS manufacturers, and testing
laboratories. NHTSA reopened the side impact protection NPRM comment
period in mid-2014 to allow stakeholders to familiarize themselves with
the Q3s, test CRSs with the ATD, and provide NHTSA with feedback in
another round of comments.
In a comment, Dorel expressed concern with the dummy being
available from only one source (HIS), and that the dummy could be
subject to patents in whole or part, thus potentially subjecting Dorel
and the CRS industry to unregulated and unbound prices. Dorel stated
that one source and supply with no competition in an open market can
lead to potential service, supply, and quality problems potentially
interrupting timely certification and delivery of CRS products to
customers. Dorel commented that allowing the continued use of the
Hybrid III dummy as an option may temporarily alleviate this concern,
but that in the long run, the lack of competition in dummy supply is a
serious issue for the manufacturers and the entire CRS community.
In response, NHTSA makes clear that, while single source
restrictions were in place during the NPRM stages (HIS retained rights
to manufacture the dummy), the Q3s dummy drawings and designs are now
free of any restrictions, including restrictions on their use in
fabrication and in building computer simulation models of the
dummy.\238\
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\238\ Q3s final rule, 85 FR 69898, 69899 (November 3, 2020).
---------------------------------------------------------------------------
2. Biofidelity
Dorel commented on the difficulties it had with the Q3s dummy in
its final development phase in areas of construction, materials,
manufacture, and qualification. Dorel believed that many aspects of the
dummy were not
[[Page 39295]]
yet finalized, such as the neck twist fixture design (Dorel said it was
completed but still needs to be validated and is not ready for sale or
purchase), and the Q3s calibration software. Dorel stated it was ready
and willing to support the rulemaking process by providing data to help
assess the repeatability and reproducibility of the dummy.
NHTSA has addressed these dummy design, qualification and
biofidelity issues in the November 3, 2020 final rule incorporating the
Q3s dummy into part 572. Since the final rule, HIS has been able to
deliver Q3s dummies within specification and at the 49 CFR part 572
design level. That final rule also addresses the stiffness of the Q3s
shoulder,\239\ with NHTSA's test data demonstrating that the Q3s
shoulder is biofidelic in the manner in which it will exert force on
the CRS.
---------------------------------------------------------------------------
\239\ 85 FR 69898.
---------------------------------------------------------------------------
JPMA commented that HIC15 may not be the most appropriate
measurement given the biofidelic limitations of the Q3s. JPMA explained
that one member noted large variation in HIC measurements with the Q3s
dummy in the proposed side impact test with relatively small changes in
the test, which it believes is due in large part to the biofidelic
limitations of the dummy. JPMA added that this member's previous
comments on the NPRM for the Q3s dummy highlighted the impact the Q3s's
shoulder stiffness could have on test results. JPMA stated that given
the lack of biofidelity in this particular region of the Q3s dummy,
HIC15 may not be the best or even most appropriate measure of side
impact protection.
Agency Response
NHTSA's November 3, 2020 final rule addresses the stiffness of the
Q3s shoulder,\240\ with NHTSA's test data demonstrating that the Q3s
shoulder is sufficiently biofidelic for the FMVSS No. 213a test. NHTSA
explained in the final rule that, under conditions that correspond
closest to the intended use of the Q3s in the proposed FMVSS No. 213
side impact test, the force response of the padded probe nearly matches
the target. With magnitude of the force generated by the padded probe
well within the envelope for a biofidelic response, these data show
that the Q3s shoulder is biofidelic as to how it loads a CRS and how it
responds to the external probe force. Thus, this loading of the child
restraint, which would affect the overall motion of the dummy's upper
torso and head (through which the FMVSS No. 213a injury criteria under
consideration would be measured), is representative of an actual human.
NHTSA concluded that the Q3s shoulder and how the ATD's shoulder, head
and torso will interact when the dummy is restrained in a child
restraint in the side impact test are sufficiently biofidelic.
---------------------------------------------------------------------------
\240\ Id.
---------------------------------------------------------------------------
In response to JPMA's concerns about the biofidelity of the Q3s
based on HIC15 fluctuations at different speeds, NHTSA's study of
repeatability and reproducibility (discussed further below) shows that
the HIC15 fluctuations are within acceptable limits.\241\
---------------------------------------------------------------------------
\241\ See Wietholter & Louden (2021).
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3. Aspects of Testing With the Q3s
i. Reversibility
JPMA stated that the NPRM for the Q3s test dummy referred to the
reversibility of the IR-TRACC and how it is to be configured, but the
corresponding NPRM for the proposed side impact test did not provide
for reversibility. JPMA added that some members reported testing of
rear-facing CRSs at Calspan that was initially conducted with the IR-
TRACC configured in the wrong direction because the NPRM for the test
itself does not mention this feature. JPMA suggested that the final
rule and test procedure specify the direction of the IR-TRACC
consistent with the final rule on the Q3s to alleviate confusion and
inconsistency.
In response, the configuration of the IR-TRACC has been
incorporated in the regulatory text of this final rule for preparing
the dummies in different CRS configurations. NHTSA's Office of Vehicle
Safety Compliance test procedure will include details as well, as
suggested by JPMA.
ii. HIII 3-Year-Old Child Test Dummy as an Alternative
NHTSA requested comment in the NPRM on the merits of using an
alternative 3-year-old child ATD in FMVSS No. 213a. The alternative
dummy was the Hybrid III 3-year-old dummy now used in the frontal crash
test of FMVSS No. 213. Comparisons between the Q3s and Hybrid III 3-
year-old ATD found that the two dummies' heads and necks provided
nearly equivalent biofidelity. However, in all other biofidelity test
conditions--shoulder, thorax and pelvis--the Q3s exhibited significant
advantages relative to the alternative HIII 3-year-old design. In the
NPRM, NHTSA stated its preference for the Q3s but sought comments on
the alternative use of the Hybrid III 3-year-old ATD instead of the
Q3s.
Comments Received
Dorel stated that it would support the temporary inclusion of the
Hybrid III 3-year-old ATD as the introduction and availability of the
Q3s was difficult from the dummy manufacturer. Dorel supported the
approach of permitting optional use of the Hybrid III for some period
of time in lieu of the Q3s dummy, adding that an option to use the
Hybrid III 3-year-old ATD could serve to fill the lack of availability
of the Q3s, as well as provide additional time to study the effects of
the Q3s.
Dorel noted the comments filed by Humanetics in Docket NHTSA-2013-
0118, which stated that NHTSA's proposal was not based on the latest
Q3s dummy. Dorel added that when the dummy drawings and specifications
change, it can affect the outcome of crash tests and cause
manufacturers to consider different countermeasures. Dorel stated that
at some point, the drawings and specifications need to be frozen so
that NHTSA and manufacturers can be certain that they are using the
same dummy in the research and, ultimately, compliance testing.
Britax and JPMA stated at that time that Britax and other CRS
manufacturers had limited opportunity to test with the Q3s ATD and so
had limited feedback to offer the agency on this topic. Britax also
stated it would favor a phased-in requirement and use of the Q3s ATD so
that, for a period of time, either ATD could be used to certify to the
side impact test requirements. Britax noted this approach was similar
to when the agency permitted use of the Hybrid II or Hybrid III ATDs
following revisions to the frontal impact sled test requirements of
FMVSS No. 213. Conversely, TRL argued that, if the Q3 has been ruled to
not adequately meet lateral biofidelity requirements, then the Hybrid
III 3-year-old should also not be used if it also does not meet side
impact biofidelity requirements.
Agency Response
NHTSA has decided against using the HIII-3-year-old dummy in the
side impact compliance test. NHTSA explained in the NPRM that
biofidelity tests showed that, while the HIII and the Q3s dummies'
heads and necks provided nearly equivalent biofidelity, the Q3s
exhibited significant advantages relative to the HIII-3-year-old in all
other test conditions (shoulder, thorax and pelvis). NHTSA agrees with
TRL that if the Hybrid III-3-year-old dummy does not adequately meet
lateral
[[Page 39296]]
biofidelity, then it should not be used to measure injury mechanisms on
the child occupant in a side impact as envisioned in the dynamic test
of FMVSS No. 213a. The agency has not found any advantage in using the
HIII-3-year-old dummy in the side impact test, and so is not adopting
use of the HIII dummy.
In their 2014 comments, Dorel and Britax supported the temporary
use of the HIII-3-year-old dummy in the FMVSS No. 213a test based on
their limited experience with the Q3s. Since 2014, manufacturers have
had years to become familiar with the dummy, and, as discussed further
in the lead time section below, manufacturers will be provided lead
time to use the Q3s before certifying their CRSs to FMVSS No. 213a.
Based on these considerations, NHTSA has decided not to use the Hybrid
III-based 3-year-old ATD, and has instead decided to adopt a final test
procedure that uses only the Q3s to evaluate injury criteria and
compliance with FMVSS No. 213a. Use of the Q3s will ensure the fullest
possible evaluation of the side protection of CRSs certified to the new
standard.
The agency's rulemaking adopting the Q3s into 49 CFR part 572
``froze'' the specifications of the test dummy in NHTSA's regulation,
as sought by Dorel's comment. Thus, the test dummy is an established
NHTSA test tool until amended through notice-and-comment rulemaking. We
note that while there were different build levels of the Q3s dummy used
throughout the development of the Q3s dummy, the January 2014 NPRM (79
FR 4570) proposing a side impact test for CRSs was based on tests using
the proposed (and now adopted) Q3s dummy.
4. Q3s Performance Measures
To determine the injury criteria to use with the Q3s ATD, NHTSA
analyzed NASS-CDS data average annual estimates (1995-2009) for AIS 2+
injuries to children 0- to 12-years-old in rear seats. Data showed that
the most common AIS 2+ injuries among children restrained in side
impacts were to the head and face (55 percent), torso (chest and
abdomen--29 percent), and upper and lower extremities (13 percent).
Given the high frequency of head and thoracic injuries to children
involved in side crashes reported in these data and in multiple
studies,\242\ NHTSA proposed appropriate injury criteria that focused
on the child occupant's head and thorax.
---------------------------------------------------------------------------
\242\ Craig, M., ``Q3s Injury Criteria,'' Human Injury Research
Division, National Highway Traffic Safety Administration (Nov. 2013)
[hereinafter Craig (2013)].
---------------------------------------------------------------------------
i. Head Injury Criterion (HIC)
NHTSA proposed to address the potential for head injuries by
setting a maximum on the HIC value measured by the Q3s in the side
impact test. HIC is used in FMVSS No. 213 and in all other
crashworthiness FMVSSs that protect against adult and child head
injury. However, while FMVSS No. 213's frontal impact requirement
specifies an injury assessment reference value (IARV) of 1,000 measured
in a 36 ms timeframe (36 ms for integrating head acceleration)
(HIC36=1,000), NHTSA proposed a HIC limit of 570 measured in a 15 ms
timeframe (15 ms duration for integrating head resultant acceleration)
(HIC15=570) when using the Q3s dummy in the side impact sled test.
NHTSA explained differences between the FMVSS No. 213 frontal
impact test and the proposed side impact test that made the HIC36=1,000
and HIC15=570 performance values appropriate for each respective test.
Specifically, FMVSS No. 213's frontal impact test evaluates the
performance of CRSs on a frontal impact sled buck that does not have a
structure (representing a front seat) forward of the tested CRS on the
bench seat. In contrast, in the proposed side impact test, there is a
simulated vehicle door and the test environment is set up so that ATD
head contact with the CRS and the door is probable. Injurious contacts
(such as head-to-door contacts) are of short duration (less than 15 ms)
in the FMVSS No. 213a set-up and are more appropriately addressed by
HIC15 (15 millisecond duration for integrating head resultant
acceleration) than HIC36.
For head impact accelerations with duration less than 15 ms, the
computed values of HIC15 and HIC36 are generally equivalent, meaning
that the injury threshold level for HIC15=570 is more stringent than
the threshold of HIC36=1,000. HIC15 is a more appropriate requirement
than HIC36 for the short duration impact of FMVSS No. 213a, and is
better able to discern injurious impact events.\243\
---------------------------------------------------------------------------
\243\ For long duration accelerations without a pronounced peak,
such as those when the head does not contact any hard surfaces (as
in the frontal FMVSS No. 213 test), the computed HIC15 value may be
lower than the HIC36 value--so the HIC36 computation may be a better
representation of the overall head acceleration.
---------------------------------------------------------------------------
NHTSA also considered alternative HIC15 requirements of 400 and
800, and included an assessment of benefits and costs of those
alternatives in the PRIA accompanying the NPRM. Ultimately, the agency
declined either as the preferred proposed injury criterion.\244\
---------------------------------------------------------------------------
\244\ PRIA at pg. 65. NHTSA concluded that the 800 HIC limit
resulted in many fewer equivalent lives saved than the proposed 570
HIC limit, higher cost per equivalent life saved, and lower net
benefits. Although the 400 HIC alternative resulted in more
equivalent lives saved and higher net benefits, NHTSA was concerned
about the effect of the 400 HIC limit on child restraint design and
use. Specifically, NHTSA was not able to demonstrate that
theoretical structural improvements to CRSs could actually achieve
the 400 HIC limit, and other means of meeting the limit would reduce
the space provided for the child's head or make the CRS wider and
heavier, which may impact overall use of the CRS.
---------------------------------------------------------------------------
Comments Received
There were no comments on the proposed HIC15 thresholds to evaluate
head injuries. NHTSA has adopted the HIC15=570 criterion for the
reasons provided in the NPRM.
ii. Head Contact (Not Assessed)
NHTSA tentatively concluded in the NPRM there was no safety need
for a performance criterion that prohibited Q3s head contact with the
intruding door.\245\ NHTSA's video analysis showed that 13 out of 19
forward-facing CRS models had head-to-door contact during the test.
However, further analysis of the head acceleration time histories
showed that peak acceleration of the head occurred before the head
contacted the door. Six of the 13 models that had head-to-door contact
had HIC15 values exceeding 570; these peak HIC15 values occurred prior
to head contact with the door. This suggested that the peak head
acceleration was the result of a previous impact, most likely the head
contacting the side of the CRS at the time the CRS contacted the
intruding door.
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\245\ Such a performance criterion for CRSs is currently being
used in the Australian standard AS/NZS 1754, and the Australian CREP
consumer information program.
---------------------------------------------------------------------------
Given that the head acceleration values computed during the time of
head-to-door contact were lower than the peak head acceleration, NHTSA
determined the risk of head injury from head-to-door contacts of the
ATD in the 13 CRSs was not only much lower than the risk from the peak
acceleration, but was also of a magnitude that would not result in
serious injury. Accordingly, the agency tentatively decided not to use
a performance criterion based specifically on head contact in tests
with the Q3s dummy, as HIC15 appeared to sufficiently discern between
non-injurious contacts and injurious contacts, and showed that head-to-
door contact was not a relevant predictor of head injury in the side
impact test.
[[Page 39297]]
Comments Received
There were a number of comments on this issue. UMTRI, ARCCA, NTSB,
and the Transportation Research Laboratory (TRL) commented that a head
containment criterion should be adopted in addition to HIC15. ARCCA
commented that notwithstanding a low HIC15 score from the Q3s head
impact with the door, there could be a risk of head injury for a child
due to the differences between the Q3s dummy and a human child, and
differences between the lab crash conditions of the FMVSS No. 213a test
and the real world. Similarly, Mr. Hauschild stated that vehicle doors
will have different designs that will include differing padding,
shapes, and trim, so data from the test seat assembly might not be
sufficient to show an absence of a safety need for a head containment
requirement.
Some commenters (Mr. Hauschild, UMTRI, NTSB) believed it would be
inconsistent to adopt a head containment performance criterion for the
12-month-old CRABI, and not for the Q3s. (NTSB raised a similar point
regarding the inconsistence of measuring HIC with the Q3s but not with
the 12-month-old CRABI. NTSB queried whether a head-to-CRS impact for
the 12-month-old CRABI dummy may be injurious in some circumstances,
implying that HIC should be a criterion in tests.)
Response
NHTSA is not adopting a head containment requirement in tests with
the Q3s. NHTSA believes there is no safety need for a performance
criterion prohibiting head contact of the Q3s because the HIC criterion
discerns between contacts that are non-injurious (HIC15 less than 570)
(soft contacts), and hard, injurious (HIC15 more than 570)) contacts.
During the FMVSS No. 213a near-side impact test the intruding door
first contacts the outer surface of the CRS, and then both the door and
CRS side structure continue intruding into the dummy's seating area and
impact the dummy. The first impact to the dummy's head happens when the
CRS side countermeasure (side wing) \246\ contacts the dummy. The HIC15
criterion evaluates whether this impact is injurious or not. Testing
showed that this impact results in a high HIC, and that head-to-door
contacts that occurred after the first impact of the head against the
CRS side wing were soft contacts. That is, head-to-door impacts did not
result in an acceleration response that would be injurious, as the HICs
were consistently below the injury assessment reference value of 570.
In light of this data, prohibiting head contact with the door as a
criterion in the side impact test would not be meaningful, as such a
prohibition would be commensurate with disallowing head contact with a
non-injurious surface.
---------------------------------------------------------------------------
\246\ The first contact could be to the SISA door, if the child
restraint has no side wing in the head area.
---------------------------------------------------------------------------
As explained above in this preamble, the stiffness of the simulated
door in the SISA is representative of the stiffness found in vehicles,
which NHTSA assessed using the free motion headform (FMH) testing
described above. The stiffness of the 51 mm thick door padding includes
the combined stiffness of the door assembly (inner and outer panel of
the door) and the interior door padding. Details of the development of
the door characteristics can be found in the ``Child Restraint Side
Impact Test Procedure Development'' technical report.\247\ Because the
simulated door is a good representation of a vehicle door, NHTSA does
not believe it is necessary to include a contact criterion when using
the Q3s dummy. On the issue of the perceived inconsistencies in how the
dummies are used in FMVSS No. 213a, as explained below, there is good
reason not to adopt a restriction against head contact by the Q3s even
though a restriction is adopted in tests with the 12-month-old CRABI.
The Q3s and the CRABI dummies are fundamentally different. As the
agency explained in the NPRM, the Q3s is a specially designed side
impact dummy, while the 12-month-old CRABI dummy is designed for use in
frontal impacts. The 12-month-old CRABI's injury-measuring
instrumentation is not designed to measure HIC in a side crash, so its
measurements of HIC to ascertain the potential for head injuries have
not been shown valid in side crashes. (This is explained in more detail
in the section below on the CRABI dummy.) If the CRABI were designed
for use in side impacts, there would be more of a basis for harmonizing
how the dummies are used in FMVSS No. 213a.
---------------------------------------------------------------------------
\247\ Sullivan et al. (2013).
---------------------------------------------------------------------------
The agency is using the CRABI dummy in FMVSS No. 213a because there
is no other suitable test dummy designed to test child restraints for
children of sizes represented by the 12-month-old dummy. NHTSA is
mandated by MAP-21 to issue a final rule to improve the protection of
children under 18.1 kg (40 lb) seated in side impacts and is
incorporating the 12-month-old CRABI in a manner that makes that
possible. While the test dummy is a frontal test dummy, it is a
valuable test tool in providing a worst-case assessment of injury risk
in a side impact regarding head-to-door contact. A CRS that is unable
to prevent the CRABI ATD's head from contacting the door in the side
impact test is highly unlikely to prevent a real child's head from
impacting the door. The head-to-door contact criterion will lead to
improved side coverage of the infant's head and better means of
preventing head-to-door contact.\248\
---------------------------------------------------------------------------
\248\ Similarly, the child restraint must maintain structural
integrity in the FMVSS No. 213a side crash when restraining the mass
of the 12-month-old CRABI. Use of the CRABI will ensure a robust
assessment of the structural integrity of the CRS in a dynamic side
crash event.
---------------------------------------------------------------------------
TRL commented that NHTSA test data from tests of the CRABI 12-
month-old seem to contradict NHTSA's conclusion that the Q3s's peak
head accelerations occur before contact with the door. The commenter
states that, in tests where the CRABI head contacts the door, the HIC15
limit is exceeded, and that the one seat that failed on head-to-door
contact recorded one of the lowest HIC values.
In response, the tests with the CRABI dummy presented in the NPRM
had a high rate of HIC15 failures, yet field experience of rear facing
seats indicates that the CRSs are very safe in side impacts (we discuss
this issue further in a section below on head-to-door contact). The
CRABI dummy's shoulder and neck are not designed for lateral loading
and this may influence head kinematics prior to contact with the CRS/
door. The CRABI head does not meet lateral biofidelity requirements.
Therefore, NHTSA is unable to confirm that the dummy's HIC measurement
provides a valid assessment of head injury risk in side impacts. Both
the severity of the resulting head contacts and the response of the
head to those contacts may not be representative of the real world.
TRL also believed that FMVSS No. 213a will encourage keeping the
HIC15 low by allowing the Q3s head to roll out of the forward-facing
CRS head pad, which increases the risk of contact between the head and
the door. TRL was concerned that possible consequences of the
standard's encouraging designs that roll out the head would be that the
head may less protected in the event of a more oblique impact, and
subject to risks of secondary impact or flying debris like broken
glass. Consumers Union (CU) also observed that the forward component of
the proposed side impact pulse caused the Q3s head to ``roll out'' of
the child restraint shell in some instances. CU stated that, with
taller forward-facing
[[Page 39298]]
seats or booster seats, the Q3s's head position will be above the top
edge (beltline) of the simulated door, so the rollout may result in a
lower HIC as the ATD's head avoids contacting the door or inside
surface of the CRS. CU argued that, although the rollout may predict
real crash dynamics, ``the lack of any interaction above the simulated
door may not be realistic. In an actual side impact crash, window
glass, pillars, or an intruding vehicle above the vehicle beltline will
likely be a point of contact for a child's head.'' \249\ CU suggested
NHTSA consider a planar limit that would reduce the potential for seats
to be designed to take advantage of the rollout of the dummy's head to
achieve low HIC values.
---------------------------------------------------------------------------
\249\ September 1, 2015 comment, p. 3.
---------------------------------------------------------------------------
In response, NHTSA disagrees that in the absence of a Q3s head
contact criterion, CRS manufacturers will design their seats in a
manner that increases the likelihood of head-to-door contact. Managing
the crash energy impacted to the dummy's head from an intruding door to
meet the HIC15=570 criterion is an engineering challenge. It is highly
unlikely that a CRS design would factor in head rollout, as managing
the energy of the impact of the head when it eventually contacts the
moving door will likely be unfeasible without managing the crash forces
through countermeasures like foam and structures engineered into the
side wings, and means to restricting the dummy's head within that
protective area.
NHTSA's testing with the Q3s dummy in actual vehicles showed the
CRS side head wing was in between the head of the dummy and the door,
as the height of the Q3s dummy's head in a CRS was positioned at or was
only partially above the windowsill. NHTSA modeled the FMVSS No. 213a
side impact test to replicate the dynamics of FMVSS No. 214 MDB tests
of actual vehicles. During the tests NHTSA conducted to model this
protocol, we did not see any intruding vehicle or pillars interacting
with the dummy. Some flexion of the CRS and dummy's head was present,
but it was not enough to contact the glass, as the dummy is not tall
enough to reach the glazing. Therefore, in response to CU, NHTSA does
not believe a planar limit for this rulemaking is necessary. Although
some rollout of the head of taller (older) occupants may occur above
the window sill due to the higher sitting height of the child, use of a
planar limit and the like addressing how CRSs should restrain the head
of taller (older) occupants is beyond the scope of this rulemaking.
iii. Chest Deflection
The agency proposed a chest displacement IARV for the Q3s of 23 mm.
The proposed 23 mm chest displacement IARV was based on two separate
studies that used length-based scaling from adult post-mortem human
subject and dummy responses to generate an estimated injury risk for a
3-year-old child.250 251 The studies both found, based on
their independent data sets, that a displacement of 23 mm represented a
30 percent and 33 percent probability of AIS 3+ injury, respectively.
---------------------------------------------------------------------------
\250\ Mertz et al., ``Biomechanical and Scaling Bases for
Frontal and Side Impact Injury Assessment Reference Values,'' 47th
Stapp Car Crash Conference, 2003-22-0009, October 2003.
\251\ Craig (2013).
---------------------------------------------------------------------------
The agency did not receive any comments on the proposed chest
deflection thresholds. NHTSA has adopted the proposed criterion for the
reasons provided in the NPRM.
b. CRABI 12-Month-Old
The CRABI dummy is a frontal crash test dummy and is instrumented
with head, neck, and chest accelerometers. NHTSA noted in the NPRM
that, while there is no infant test dummy available that is specially
designed for side impact testing, the agency believed that the CRABI
12-month-old could be a useful tool to evaluate critical aspects of CRS
performance in side impacts. Because children under 1-year-old have the
highest restraint use, NHTSA sought to find a way to evaluate the side
impact performance of the CRSs they use, even if the evaluation is
limited to containment, structural integrity, and other related
matters.
1. Alternative ATDs
Several commenters suggested developing a new 12-month-old dummy to
assess side impact performance. Graco suggested considering developing
a Q1s (Q-series one-year-old), as did TRL, which argued that the Q1 is
used for front and side impact testing in United Nations (U.N.)
Regulations No. 44 (R.44) and No. 129 (R.129) \252\ and would allow
head accelerations to be assessed.
---------------------------------------------------------------------------
\252\ United Nations Economic Commission for Europe (UNECE).
Regulation 44, ``Child Restraint Systems'' and UNECE Regulation 129,
``Enhanced Child Restraint Systems.''
---------------------------------------------------------------------------
While NHTSA has not evaluated the Q1 dummy, NHTSA does not believe
the Q1 dummy, which is a scaled version of the Q3 dummy, is biofidelic
in side impact. NHTSA had evaluated the Q3 dummy and found it was not
biofidelic in side impact. As a result, NHTSA conducted extensive
research on modifications to the Q3 dummy design to improve its
biofidelity in side impact. This multi-year agency effort led to the
development of the Q3s dummy. NHTSA believes it is unnecessary to delay
the final rule further to conduct multi-year research for developing a
version of the Q1 dummy with appropriate biofidelity in side impact.
The agency believes the use of the CRABI 12-month old dummy, along with
the restriction protecting against head contact in the side test, will
enhance the side crash protection of these CRSs.
2. Durability
JPMA raised concerns about the durability of the CRABI dummy,
stating that in some tests the CRABI 12-month-old's arm broke at the
elbow. The commenter stated that the attendant replacement costs of the
dummy's upper arm was approximately $900, which JPMA said was a very
significant expense if repeated during many test cycles. JPMA said its
members reported that, during the side impact event, the test dummy's
arm gets crushed between the side of the seat (which is impacted by the
door panel feature) and the test dummy's torso, and that there is
sufficient deflection at this point to break the elbow. Similarly,
while Graco commented in support of the use of the 12-month-old CRABI
dummy, it noted some concerns with long term maintenance of the dummy
over time.
In response, during the development period of the side impact test
protocol, and with over 50 tests with the 12-month-old CRABI dummy at
VRTC, NHTSA did not observe arm breakage as described by JPMA.\253\
Also, during testing at Kettering University (discussed in a section
below), only one 12-month-old CRABI dummy test resulted in a fractured
arm. NHTSA believes the problem with the arm breakage may have been due
to an anomaly in the dummy set up in the JPMA tests. NHTSA is not aware
of data demonstrating that the dummy's durability renders the dummy
insufficient for use in the FMVSS No. 213a side impact test.
---------------------------------------------------------------------------
\253\ In a test at VRTC an arm and leg were broken, but the
breakage occurred to the arm and leg on the opposite side of impact
(i.e. the impact was to the right side of the dummy but the breakage
was to the left arm and leg). NHTSA believes the broken arm and leg
on the opposite side of impact were a result of anomalous and
undetermined factors and were not related to the durability of the
dummy.
---------------------------------------------------------------------------
NHTSA also notes that, in the years since the 2014 NPRM preceding
this
[[Page 39299]]
final rule, and during the course of the testing of the Q3s in support
of the rulemaking incorporating the dummy into 49 CFR part 572,\254\
NHTSA has not learned of any dummy durability issues with the Q3s dummy
as well.
---------------------------------------------------------------------------
\254\ 85 FR 69898, supra.
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3. Head-to-Door Contact
NHTSA proposed to use the CRABI 12-month-old ATD to measure head-
to-door contact only, and not HIC15, noting concerns about the real-
world relevance of the HIC values measured using the CRABI 12-month-old
during developmental side impact testing. NHTSA presented results of 12
tests performed with rear-facing CRSs using the CRABI 12-month-old that
showed nearly all of the CRSs exceeded the HIC15 injury threshold value
of 390, which is the injury criteria used in FMVSS No. 208. NHTSA
hypothesized that the CRABI 12-month-old dummy's shoulder and neck were
not designed for lateral loading, which may influence head kinematics
prior to contact with the CRS/door. Therefore, NHTSA concluded that
both the severity of the resulting head contacts and the response of
the head to those contacts may not be representative of the real world.
Although tests with the CRABI 12-month-old showed many of the CRSs
did not meet a HIC15 criterion, field experience of rear-facing seats
indicate that the CRSs are very safe in side impacts and provide five
times more protection against serious injury than forward-facing seats
in side impacts.\255\ Accordingly, NHTSA has decided to use the CRABI
12-month-old to assess safety risks related to a CRS's ability to limit
head-to-door contact in side crashes. The CRABI 12-month-old will
provide a worst-case assessment of injury risk in a side impact in
terms of head-to-door contact. That is, if the CRS were unable to
prevent the ATD's head from contacting the door in the test, such an
outcome is a reasonable indication of an unacceptable risk of head
contact by the human child. NHTSA's study of 12 tests using the CRABI
12-month-old in rear-facing CRSs showed that 1 (Combi Shuttle) out of
12 rear-facing CRS models tested had head-to-door contact during the
test. A head-to-door criterion for assessing CRSs tested with the CRABI
12-month-old will ensure all rear-facing seats will have sufficient
side coverage to protect in side impacts. Moreover, the CRABI dummy is
a suitable test device to assess a CRS's ability to maintain its
structural integrity in side crashes when restraining 1-year-old
children (discussed further below).\256\
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\255\ Sherwood et al. (2007).
\256\ NHTSA did not propose a chest injury criterion for the
CRABI. Biofidelic corridors for 12-month-old children are not
available. Also, because the small size of a 12-month old dummy
makes it difficult to fit instrumentation in such limited space, it
may not be feasible to build and fully instrument a dummy this size
for side impacts.
---------------------------------------------------------------------------
4. Component Test
TRL expressed concern about the standard's not measuring loading on
the 12-month-old CRABI dummy in rearward-facing seats, and stated that
a possible unintended consequence could be that CRS side structures
could be stiffened to prevent the head-door contact, which could
increase loading to the child's head. TRL suggested that NHTSA could
assess the energy absorption capabilities of the CRS in the form of a
headform drop test measuring the ability of the side wings to manage
impact energy. TRL explained that this type of component testing is
currently conducted as part of the R.44/R.129 type-approval testing.
NHTSA considered this matter and collaborated with Transport Canada
(TC) to evaluate new and existing component level tests that could
evaluate the energy-absorption capability of the side structure of
CRSs. Transport Canada evaluated energy absorption methodologies
(including the ECE R.129 head drop test) \257\ to potentially
incorporate into FMVSS No. 213a and Canada Motor Vehicle Safety
Standard (CMVSS) No. 213, but found that the procedure in the European
standard does not adequately discriminate between materials that are
and are not energy absorbing.\258\ NHTSA and TC were unable to find a
suitable methodology that could be used to evaluate energy absorption
capabilities of the side structure of CRSs.\259\
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\257\ Head drop tests specifying a 60 g head form threshold and
a drop height of 100 mm.
\258\ Hallaoui, K.E., Cohen, M., Tylko, S. ``Child Restraint
Headrest Conformity Test Document.'' April 2017. To be docketed
along with this final rule.
\259\ FMVSS No. 213 had a head impact protection requirement for
rear-facing CRSs that required areas contactable by the dummy's head
to be covered with slow recovery, energy absorbing material. That
requirement was removed when the 12-month-old CRABI dummy was
adopted into FMVSS No. 213 and HIC was introduced as a performance
measure. The agency decided against this approach for FMVSS No. 213a
because not enough is known about a foam specification to
distinguish between effective and ineffective foams.
---------------------------------------------------------------------------
5. CRS System Integrity and Energy Distribution
NHTSA proposed to require child restraints to maintain system
integrity when dynamically tested with the Q3s and CRABI 12-month-old
dummies. When a CRS is dynamically tested with the appropriate ATD,
there could not be any complete separation of any load-bearing
structural element of the CRS, or any partial separation exposing
surfaces with sharp edges that may contact an occupant. These
requirements would reduce the likelihood that a child using the CRS
would be injured by the collapse or disintegration of the system in a
side crash, or by contact with the interior of the passenger
compartment or with components of the CRS.
Injury from contacting protrusions, such as the pointed ends of
screws mounted in padding, would be prevented in a similar manner as
that specified for the frontal crash test in FMVSS No. 213. The height
of such protrusions would be limited to not more than 9.5 mm (0.375
inch) above any immediately adjacent surface. Also, contactable
surfaces (surfaces contacted by the head or torso of the ATD) could not
have an edge with a radius of less than 6.35 mm (0.25 inch), even under
padding. Padding would compress in an impact and the load imposed on
the child would be concentrated and potentially injurious.
Comments Received
CU suggested that NHTSA consider acceptance criteria that address
the ability of the seat to maintain the connection between the carrier
portion of seats and their corresponding bases. CU explained that,
although separation of the carrier and base connection may be
interpreted as a separated load-bearing structural element per
currently proposed acceptance criteria, it may warrant its own
performance requirement. CU added that NHTSA should consider partial
separations in load-bearing areas that may significantly reduce a
seat's ability to contain its occupant or to remain attached to the
vehicle seat as potential non-compliances with the standard. CU
explained that rear-facing bases, for example, could exhibit
significant levels of cracking that will never be considered
contactable, but which could potentially significantly degrade a seat's
ability to remain attached to a vehicle.
Agency Response
Structural integrity will be evaluated with the same criteria in
the current FMVSS No. 213 S5.1.1. The objectives of the system
integrity requirements are to prevent ejection from the restraint
system and to ensure that the system does not fracture or separate in
such a way as to harm the child. Structural integrity requirements
require CRSs dynamically tested with the appropriate dummy have no
complete separation of
[[Page 39300]]
any load bearing structural element of the system or any partial
separation exposing surfaces with sharp edges that may contact an
occupant. The agency amended FMVSS No. 213 to allow some partial
separations in response to comments from CRS manufacturers that stated
that some CRS separations (e.g., hairline fracturing) could be
purposely designed into the CRS to improve its energy absorption
performance.\260\ NHTSA did not see any cracking or evidence of poor
infant carrier retention during side impact testing. These requirements
have ensured the structural integrity of child restraints in frontal
impacts for years. The commenter did not provide sufficient reasons for
concluding additional requirements for evaluating structural integrity
are necessary in side impacts.
---------------------------------------------------------------------------
\260\ 43 FR 21470 (May 18, 1978).
---------------------------------------------------------------------------
IX. Repeatability and Reproducibility
The Vehicle Safety Act requires FMVSS that are practicable, meet
the need for motor vehicle safety, and stated in objective terms.\261\
In proposing FMVSS No. 213a, NHTSA determined that the Takata-based
test procedure produced repeatable results and was able to provide
results that distinguished between the performance of various CRS
models based on the design of the side wings and stiffness of the CRS
padding.\262\ Similarly, based on evaluations of the Q3s going back to
2002, the agency determined that the Q3s demonstrated good biofidelity,
repeatability, reproducibility, and durability.\263\ In the NPRM, NHTSA
outlined its plans to evaluate the repeatability and reproducibility of
the proposed sled test procedure in different laboratories, and sought
comments on what parameters, additional to the proposed specifications,
should be specified to reproduce the test procedure on a deceleration
sled.\264\
---------------------------------------------------------------------------
\261\ 49 U.S.C. 30111(a).
\262\ 79 FR at 4582 (Jan. 28, 2014) (citing Sullivan et al.
(2009), Sullivan et al. (2011)).
\263\ NPRM, 79 FR at 4590 (Jan. 28, 2014); final rule, 85 FR
69898 (Nov. 3, 2020).
\264\ ``Repeatability'' is defined here as the similarity of
test responses (dummy injury measures) when subjected to multiple
repeats of a given test condition. ``Reproducibility'' is defined as
the similarity of test responses subjected to repeats of a given
test condition in different test laboratories.
---------------------------------------------------------------------------
Several commenters discussed the importance of the repeatability
and reproducibility of the procedure and provided suggestions to
improve repeatability. Dorel emphasized that reproducibility between
test facilities is an essential requirement of an objective safety
standard and that NHTSA must specify the test procedures for its FMVSS
in sufficient detail to ensure that the tests conducted at one test
facility will yield results that are essentially identical to the
results at a different test facility when the same product is tested.
Dorel stated that reproducibility is critical to the CRS industry, and
opined that reproducibility is a significant challenge with current
FMVSS No. 213.
Dorel stated it conducted a series of side impact tests of the
Safety First Air Protect CRS Model at Calspan (a commercial testing
facility) on a Hyge \265\ sled utilizing a test fixture constructed
from the NPRM drawings. Dorel said the tests showed HIC15 values of 313
and 354, while NHTSA's NPRM test data on the same CRS Model provided
showed HIC15 values of 424, 566, and 625. Dorel calculated the
coefficient of variation (CV) of the HIC15 values as 8.7 for the
Calspan tests, while the CV for NHTSA's tests was 19.2 for HIC values.
Dorel believed that these results indicate a significant problem in the
repeatability and reproducibility of the proposed test method.
---------------------------------------------------------------------------
\265\ Hyge is a type of acceleration sled.
---------------------------------------------------------------------------
Graco stated it conducted more than 110 side impact crash test
trials in response to the 2014 proposal and studied repeatability and
reproducibility of 5 types of CRSs (rear-facing infant carrier, rear-
facing convertible CRS, forward-facing convertible CRS, 3-in-1 forward-
facing CRS, and high-back booster seat). Graco stated it tested 8
different CRS models multiple times at three crash test facilities,
using different sized dummies, to determine if results are repeatable
within the same test facility and reproducible at different test
facilities with acceleration-type sleds. The commenter stated there was
significant variation across the test facilities and provided HIC15
data of a Q3s dummy from the three test facilities to illustrate
differences in test results from different test facilities for a
specific CRS.\266\ Graco said there were cases where a seat with
passing results at a specific test facility produced failing results at
another test facility. Graco surmised that the different HIC15 values
were most likely due to the differences in the sliding seat
acceleration and in head acceleration when the CRS impacts the door.
Graco explained that the test facility that produced the failing result
at the time the head impacted the door, had a greater sliding seat
acceleration than the other two facilities.
---------------------------------------------------------------------------
\266\ NHTSA-2014-0012-0042, at pg. 2.
---------------------------------------------------------------------------
Graco also provided data of chest deflection of the Q3s dummy from
tests conducted at the three test facilities, to illustrate differences
in the chest deflection results at different test facilities.\267\
Graco reiterated that there were cases where a CRS with passing chest
deflection results at one test facility produced failing results at
other test facilities. Graco believed that since the timing of these
high chest deflection measurements occur at the same time as the HIC15
measurements, the same factors contributed to the variation in
measurements of chest deflection and HIC15 values across the different
test facilities (i.e., differences in sliding seat acceleration and
acceleration of the thorax at the time of contact with the door foam).
---------------------------------------------------------------------------
\267\ Id., at pg. 3.
---------------------------------------------------------------------------
Graco provided initial test data on the potential cause of
variation and provided its recommendations on sled design and other
factors to reduce the variation in results between test facilities.
Britax stated that it is essential that the test procedure's
provisions for seat and ATD installation are described in sufficient
detail to ensure consistency in test results and ATD measurements.
Britax also stated that defining specifications for variables such as
the test rig foam and set up are critical to achieving repeatable and
consistent results.
Agency Response
NHTSA has modified the SISA to minimize sources of variability in
the test and to make the test setup more durable. The modifications
reduced vibrations that affect accelerometer readings, defined
accelerometer processing and the type and location of the
accelerometers, and defined a different honeycomb with a reduced
tolerance to minimize variation. NHTSA's modifications also enable the
SISA to better match the changes to the FMVSS No. 213 frontal impact
sled test seat assembly proposed in the November 2, 2020 MAP-21 NPRM,
supra. These modifications included additional stiffening of the seat's
framework, an updated D-ring location, increased seat back height,
simplified door and armrest shapes, modified lower anchor bracket and
tether anchor location, defined seating foam, and incorporation of a
seat cushion assembly representative of current vehicles. NHTSA also
defined in more detail the procedure for setting up the CRS and ATD
prior to testing (including
[[Page 39301]]
arm placement, discussed further in a section below), modified SISA
drawing specifications to eliminate any ambiguities, and specified the
weight of the sliding seat at test facilities, as the weight affects
the pulse generated by the sliding seat/honeycomb impact.
These modifications improved the R&R of the FMVSS No. 213a test.
The modifications to the SISA reduced the variability of test results.
Some improvements to R&R also resulted from further developing the
level of detail in the test procedure, as suggested by some commenters.
NHTSA believes that the variability in tests manufacturers performed at
different laboratories was partly because there was no detailed test
procedure during the NPRM phase specifying how the FMVSS No. 213a test
should be conducted.
With a detailed test procedure, NHTSA tests at two different test
facilities with different sled systems (acceleration and deceleration
types) were able to produce repeatable and reproducible results.\268\
The details of the improvements are described at length in the
technical reports by VRTC \269\ and NHTSA/Kettering.\270\ The updated
technical drawings of the SISA are available in the docket of this
final rule.
---------------------------------------------------------------------------
\268\ The test procedure followed during NHTSA's testing can be
found in the technical report, ``FMVSS No. 213 Side Impact Test
Evaluation and Revision,'' available in the docket of this final
rule.
\269\ Louden & Wietholter (2022).
\270\ Brelin-Fornari, J., ``Final Report on CRS Side Impact
Study of Repeatability and Reproducibility using a Deceleration
Sled,'' July 2017. Available in the docket for this final rule.
---------------------------------------------------------------------------
After improving the test procedure and SISA, the agency conducted
tests on six CRS models to evaluate repeatability at VRTC with the
acceleration sled, and on five of the same six CRS models to evaluate
repeatability at Kettering University with the deceleration sled. NHTSA
sought to evaluate the reproducibility of the test results from the two
test facilities.\271\ The coefficient of variation (CV) \272\ was used
to objectively evaluate the repeatability and reproducibility of the
FMVSS No. 213a side test fixtures and procedures. The CV is calculated
by dividing the standard deviation by the average; multiplying the CV
by 100 computes the percent CV. For assessing repeatability and
reproducibility, a CV value less than or equal to 5 percent was
considered as excellent, a CV value between 5 and 10 percent was
considered as good, a CV value between 10 and 15 as marginal, and CV
values above 15 were considered poor. Since variation in test results
is likely contributable to more than just the test fixtures, dummies
and procedure, a percent CV at or below 10 percent indicates results
are similar. Other sources of variability include, but are not limited
to, pulse variation, and variability related to differences in the CRS
test specimens as produced.
---------------------------------------------------------------------------
\271\ Wietholter, K. & Louden, A. (2021, November).
Repeatability and Reproducibility of the FMVSS No. 213 Side Impact
Test. Washington, DC: National Highway Traffic Safety
Administration.
\272\ NHTSA has used CVs to assess the repeatability and
reproducibility of ATDs throughout the history of Part 572, starting
in 1975. See NPRM for the original subpart B Hybrid II 50th
percentile male ATD (40 FR 33466; August 8, 1975).
---------------------------------------------------------------------------
The test program showed good to excellent repeatability and
reproducibility in the test results. Table 24 shows the CRS models,
orientation and CV values at each of the two test facilities to
evaluate repeatability. The CV values for HIC and chest deflection in
tests conducted at VRTC with the Q3s dummy were less than 5 percent and
are considered excellent for repeatability.\273\ The CV values for HIC
and chest deflection in tests conducted at Kettering with the Q3s dummy
were less than 5 percent (except for chest deflection measured in the
rear-facing convertible (Graco Comfort Sport) which had a CV value of
16.1 percent).
---------------------------------------------------------------------------
\273\ The CV values for HIC results in tests conducted at VRTC
with the CRABI 12-month-old dummy were less than 8 percent showing
good repeatability as well; however, this was analyzed for
comparison purposes only, as the final FMVSS No. 213a test procedure
only evaluates CRABI 12-month-old head containment on a pass/fail
basis.
Table 24--Coefficient of Variation (CV) for Assessing Repeatability and Reproducibility
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
VRTC CV% Kettering CV% VRTC and Kettering
-----------------------------------------------------------------------------------------------
ATD CRS Orientation Chest Chest Chest
H1C15 deflection H1C15 deflection H1C15 deflection
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Q3s..................................... Evenflo Maestro........... FF Combination **......... 4.3 1.3 4.4 1.4 4.2 1.2
Q3s..................................... Grace Comfort Sport....... FF Convertible **......... 4 3.1 2.1 1.9 3.4 3.6
Q3s..................................... Grace Comfort Sport....... RF Convertible............ 3.6 2.5 3 16.1 16 -10.5
Q3s..................................... Diono Olympia *........... RF Convertible............ .............. .............. .............. .............. 2.3 ..............
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* The Diono Olympia had fewer tests per test facility compared to the rest in this analysis. The Diono Olympia was tested once at VRTC and twice at Kettering. The CV for Chest Deflection was
not calculated as an instrumentation problem caused an erroneous reading in the test at VRTC.
** All forward-facing CRSs were installed using the lower anchors and tether anchor of CRAS and all rear-facing CRSs were installed using lower anchors only.
[[Page 39302]]
It is unknown why the results for the Graco rear-facing convertible
were elevated; NHTSA could not perform additional testing under the
contract. Possibilities include limited testing, variation in test set-
up, variation in the overall relative velocity at impact time (while
within the tolerance it was higher than other repeat tests) and/or
other factors (i.e. CRS sensitivity). CVs obtained elsewhere were not
as high and were in the acceptable range. While not part of this test
series, during the development of the NPRM, NHTSA/Kettering performed
side impact tests with a deceleration-type sled. Tests with the Combi
Zeus and Britax Advocate in rear-facing configuration with the Q3s
dummy \274\ showed CV values of only 4.9 percent and 4.2 percent
respectively for chest displacement. These results show an excellent CV
for chest displacement in testing with a deceleration-type sled
test.\275\ NHTSA believes that more tests at Kettering troubleshooting
the increased CV value of 16.1 percent would have resulted in a reduced
CV.
---------------------------------------------------------------------------
\274\ Three repeat tests were performed for each model. Test
results are documented in the technical report DOT HS 811 994 and
995. Brelin-Fornarni, J., ``Development of NHTSA's Side Impact Test
Procedure for Child Restraint Systems Using a Deceleration Sled:
Final Report, Part 1. April 2014. Link: https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/811994-sideimpcttest-chrestraintdecelsled_pt1.pdf and Brelin-Fornarni, J., ``Development
of NHTSA's Side Impact Test Procedure for Child Restraint Systems
Using a Deceleration Sled: Final Report, Part 2. May 2014. Links:
https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/811994-sideimpcttest-chrestraintdecelsled_pt1.pdf and https://www.nhtsa.gov/sites/nhtsa.gov/files/documents/811995-sideimpcttest-chrestraintdecelsled_pt2.pdf.
\275\ These tests were performed with the NPRM proposed SISA and
honeycomb; however, as discussed above, updates to the SISA since
the NPRM did not affect results. Therefore, we consider the
repeatability results of the NPRM tests with the deceleration type
sled valid.
---------------------------------------------------------------------------
The tests performed with the CRABI 12-month-old dummy (see Table 25
below) provided consistent head contact results at each test facility
(that is, the result of whether there was contact of the head with the
door was the same for all the repeat tests with the same CRS in both
test facilities).
Table 25--Side Impact Tests Using the CRABI 12-Month-Old Dummy
----------------------------------------------------------------------------------------------------------------
CRS Orientation VRTC Kettering Door contact
----------------------------------------------------------------------------------------------------------------
Chicco KeyFit 30...................... Rear Facing............. 3 3 No.
Britax Boulevard...................... Rear Facing............. 3 3 No.
Cosco Apt 40.......................... Forward Facing.......... 3 1 No.
----------------------------------------------------------------------------------------------------------------
The CV values for HIC and chest deflection measures for each CRS
model from tests conducted in both test facilities with the Q3s dummy
considered together were generally lower than 5 percent. Only one CRS
model in rear-facing configuration using the Q3s dummy at both test
facilities had a CV value of 10.5 percent for chest deflection and a 16
percent CV for HIC15 when the data from the two test facilities for
this CRS were combined. While these results suggest that HIC measures
of the Q3s dummy in rear-facing CRSs have poor reproducibility (high CV
values), this result is based on test data of one CRS model (Graco
Comfort Sport), which also had poor repeatability measures in one of
the test facilities. As discussed above, it is unknown why this CRS had
poor repeatability. The CV of HIC15 measures from a more limited set of
tests with the Diono Olympia CRS in the rear-facing configuration using
the Q3s dummy (one test at VRTC and two tests at Kettering) was 2.3
percent, showing excellent repeatability in a rear-facing CRS with the
Q3s dummy. Details on the repeatability and reproducibility analysis
can be found in the docket for this final rule.\276\
---------------------------------------------------------------------------
\276\ Wietholter, K. & Louden, A. (November 2021). Repeatability
and Reproducibility of the FMVSS No. 213 Side Impact Test.
Washington, DC: National Highway Traffic Safety Administration.
---------------------------------------------------------------------------
The CV analysis confirms good repeatability and reproducibility of
HIC and chest deflection measures in forward-facing CRSs tested with
the Q3s dummy. Rear-facing infant tests with the CRABI 12-month old
showed good repeatability and reproducibility for assessing head-to-
door contact. CV analysis of rear-facing convertible CRSs with the Q3s
had inconclusive results, possibly due to the limited number of data
points. The limited test series between the two test facilities with a
rear-facing convertible (Diono Olympia) showed HIC15 had a 2.5 percent
CV, showing good repeatability and reproducibility with a rear-facing
CRSs tested with the Q3s dummy. Chest deflection could not be computed
as the test at VRTC had an erroneous chest deflection reading.
NHTSA's CV analysis of the side impact tests with the final
configuration of the SISA demonstrates that the changes to the
configuration of the SISA and adoption of some of the modifications
suggested by commenters (see next section), have addressed the
repeatability and reproducibility concerns raised by the commenters.
NHTSA has found the variability in the performance measures is within
acceptable levels; the repeatability and reproducibility of the side
impact test is considered good to excellent. Accordingly, NHTSA has
determined that the side impact test, using the dummies specified in
the standard to determine compliance with the standard, produces
repeatable and reproducible results in repeat tests in the same
facility and in multiple tests across different test facilities.
Commenters' Other Suggestions
Accelerometer Placement
Graco recommended that NHTSA provide specifications for
accelerometer placement and accepted types, so that data acquisition
for velocity and acceleration could be more consistent between test
facilities. Graco noted it saw differences in test labs'
interpretations of the proposed side impact testing specifications for
using the accelerometers, and provided a diagram of differing
accelerometer placement locations between facilities. The commenter
also provided an acceleration plot demonstrating how different
accelerometer types represent the acceleration pulse differently. Graco
stated that by defining the location and accepted options for dampened
accelerometers, acceleration and velocity measurements can be more
standardized to prevent inconsistent calculations of raw data.
Agency Response
NHTSA tested many accelerometer locations \277\ on the sliding seat
and determined that the final placement of the accelerometers will be
on the right rear seat assembly leg at predetermined locations; with
the primary
[[Page 39303]]
accelerometer to be mounted on top and the redundant to be mounted 31
millimeters below.\278\ The selected locations produced the more
consistent and less noisy measurements during testing. The final
locations of the accelerometers are specified in the final drawing
package. The final drawings have also been modified so that the
accelerometer specifications allow compliance test facilities to use
different brands of accelerometers and prevent sourcing issues in the
future.\279\
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\277\ See the following report for documented accelerometer
placement trials. Louden, A., & Wietholter, K. (September 2022).
FMVSS No. 213 side impact test evaluation and revision (Report No.
DOT HS 812 791). Washington, DC: National Highway Traffic Safety
Administration (hereinafter Louden & Wietholter (2022)). Available
in the docket of this final rule.
\278\ This information is discussed in detail in NHTSA's ``FMVSS
No. 213 Side Impact Test Evaluation and Revision'' report.
\279\ During the agency's testing, we found that the type of
accelerometer (damped, undamped, ruggedized, etc.) has an effect on
the results as different accelerometers may pick up different
vibration levels.
---------------------------------------------------------------------------
Belt Engagement
Graco stated it found that, during the time of engagement between
the aluminum honeycomb and the impact surface of the sliding seat, the
Type 2 shoulder belt is engaged with the door structure, which can
affect the sliding seat acceleration pulse. Graco provided images that
it believed demonstrates the interference of the shoulder belt webbing,
and a graph that displays a modified acceleration pulse profile caused
by this interference, compared to an acceleration profile without this
interference. Graco recommended NHTSA consider removing this
interference of the Type 2 shoulder belt as a control for repeatability
of the acceleration pulse.
Agency Response
NHTSA's testing with the CRS installed using the Type 2 (lap/
shoulder belt) showed no interference of the shoulder portion of the
Type 2 belt with the door.\280\ The agency found that in testing, the
shoulder portion of the Type 2 belt slides behind the door during
contact of the sliding seat with the door. This interaction did not
affect the sliding seat acceleration pulse or any of the performance
measures.
---------------------------------------------------------------------------
\280\ Additional pictures to illustrate the seat belt sliding
behind the seat back are available in the docket for this final
rule.
---------------------------------------------------------------------------
NHTSA also performed a static trial with the Graco Nautilus, which
is the model Graco showed had seatbelt-door interaction. In that trial,
the seat belt webbing lay flat against the top of the seat back, which
would allow the seat back to go through the door and seat back
gap.\281\ NHTSA was not able to reproduce Graco's seat belt interaction
with the door. The agency believes that any possible seatbelt-door
interaction is avoided by ensuring the seat belt lies flat against the
seat back. The test procedure will incorporate a step to ensure the
seat belt lies flat before testing.
---------------------------------------------------------------------------
\281\ Additional pictures to illustrate the seat belt sliding
behind the seat back are available in the docket for this final
rule.
---------------------------------------------------------------------------
Test Facilities
Dorel expressed concerns about test facilities conducting
compliance tests for NHTSA not following the agency's Office of Vehicle
Safety Compliance's (OVSC's) published test procedures and not
obtaining OVSC's express permission to deviate. The commenter urged
NHTSA to increase oversight of the test labs to enhance repeatability
and reproducibility of the compliance test results. In response, NHTSA
has reviewed its compliance program and has not found evidence of the
problem the commenter describes. NHTSA is nonetheless concerned about
assertions that deviations from protocols have reduced the integrity of
the FMVSS No. 213 tests, so it is emphasizing again to its test lab to
use the open and strong channels of communication set up by OVSC for
any questions about test procedures or practices. Further, the agency
will unreservedly consider ways to improve any issue arising in the
course of OVSC testing that impact the quality of the compliance test
program.
Dorel stated that it has had concerns about the repeatability and
reproducibility of the current frontal impact sled test in FMVSS No.
213. In response, the frontal impact sled test has been effectively
used in FMVSS No. 213 compliance tests for over forty years and is
instrumental in the assessment of a child restraint's real-world
performance in a crash.\282\ In 2020, NHTSA took steps to update the
sled assembly and strengthen its technical underpinnings by way of the
November 2, 2020 NPRM responding to MAP-21.\283\ The agency is
analyzing comments received on that NPRM and will address all relevant
comments relating to the R&R of the frontal sled assembly in the final
rule.
---------------------------------------------------------------------------
\282\ 44 FR 72131 (December 13, 1979), 45 FR 27045, seat
assembly updated, 68 FR 37620 (June 24, 2003).
\283\ MAP-21 (Sec. 31501(b)(2)) requires NHTSA to issue a final
rule to amend Standard No. 213 to better simulate a single
representative motor vehicle rear seat. The regulation information
number (RIN) for the rulemaking is RIN 2127-AL34. It may be tracked
in the U.S. government's Unified Agenda of Regulatory and
Deregulatory Actions.
---------------------------------------------------------------------------
X. Lead Time and Effective Date
NHTSA proposed a compliance date of three years from the date of
publication of the final rule, meaning that CRSs manufactured on or
after that date must meet FMVSS No. 213a. NHTSA proposed to permit
optional early compliance with the requirements, to permit
manufacturers the option of meeting FMVSS No. 213a sooner than the 3-
year compliance date and certifying the compliance of their products to
the standard.
NHTSA discussed in the NPRM its tentative determination that there
was good cause to provide three years of lead time. The agency believed
three years was a reasonable time for CRS manufacturers to gain
familiarity with the new side impact standard, the test using the SISA,
and the Q3s dummy adopted by the standard. Manufacturers would have to
assess the entirety of their product line for conformance to the new
standard, devise and incorporate any needed design changes to meet the
standard, implement the changes in manufacturing processes for the
seats, and certify the compliance of the child restraints. NHTSA
believed that three years of lead time provides a timeframe that allows
manufacturers to achieve these actions while ensuring the enhanced side
impact protection adopted by FMVSS No. 213a is attained as quickly as
possible.
Comments Received
Commenters diverged as to the need for a three-year lead time.
Child restraint manufacturers commenting on this issue agreed with the
proposed lead time. Dorel concurred that a three-year lead time was
sufficient, but conditioned its support for this lead time on NHTSA's
findings that the test procedure was sufficiently objective to
eliminate test-to-test repeatability problems and test facility-to-
facility reproducibility problems. In contrast, Safe Ride News (SRN),
Safe Kids Worldwide, Mr. Hauschild, Consumers Union (CU), and ARRCA
suggested a reduced lead time, from 18 months to two years at the most
(SRN and Safe Kids).
Some of the latter commenters argued that manufacturers have
already incorporated side impact protection into many of their
products, and that the number of children who could be protected by a
side impact standard is significant enough to shorten the lead time.
Mr. Hauschild stated that, since many of the CRS manufacturers are
advertising that their CRSs have side impact protection or that their
seats have been side impact tested, they should have no problem meeting
the lead time requirements, and may be able to meet the requirement
sooner. CU urged NHTSA to shorten the three-year compliance deadline,
arguing that MAP-21 was issued in 2012, and that, even then, NHTSA had
been working on
[[Page 39304]]
a side protection standard for years, which should have provided notice
to manufacturers that such new side impact requirements were coming.
ARRCA believed the FMVSS No. 213a test procedure is not complex and
that test facilities should be able to configure their sleds with the
required hardware within a month of the final rule being published.
ARRCA believed that upgrading the CRSs that do not comply or removing
them from the market should be capable of being accomplished within a
year of the final rule. ARRCA argued that, under NHTSA's preliminary
cost-benefit analysis for the NPRM, a one-year effective date would
save the lives of approximately 36 children.
Agency Response
NHTSA is adopting the proposed lead time of three years from the
publication date of this final rule. In response to Dorel, the test
procedure has been demonstrated to be both repeatable and reproducible,
as discussed above and in detail in the report, ``Repeatability and
Reproducibility of the FMVSS No. 213 Side Impact Test,'' \284\ so the
provided lead time will be sufficient.
---------------------------------------------------------------------------
\284\ Wietholter & Louden (2021).
---------------------------------------------------------------------------
In response to commenters seeking a shorter lead time, NHTSA has
decided against a compliance date less than three years from the date
of publication of this final rule for several reasons. This final rule
makes modifications to the SISA to minimize sources of variability in
the test, make the test setup more durable and increase the
representativeness of the SISA to today's vehicles. The rule matches
the SISA to the FMVSS No. 213 frontal impact sled test seat assembly
proposed in the November 2, 2020 NPRM, supra. This final rule also
defines in more detail the procedure for setting up the CRS and ATD
prior to testing (including arm placement, which can affect test
results), specifies the weight of the sliding seat at test facilities,
and makes other changes to improve the R&R of the test. Manufacturers
will need time to become familiar with the SISA as set forth in this
final rule and will need time to test their child restraints on the
SISA adopted by this final rule. The agency believes manufacturers will
seek to test their products on the SISA, and with the Q3s dummy, to
maximize the possibility that the test they use for certifying their
products aligns with the test NHTSA uses in the FMVSS No. 213a
compliance test. The agency adopted the Q3s into regulation by a final
rule only in 2020, so manufacturers will need time to acquire and test
with the dummy.\285\
---------------------------------------------------------------------------
\285\ The Q3s dummy was adopted in a final rule published on
November 3, 2020 (85 FR 69898). While the agency was developing the
final rule, the agency realized that some of the Q3s dummies that
had been delivered to CRS manufacturers and test facilities
following the publication of the 2014 NPRM did not meet the
specifications NHTSA had proposed for the dummy. The three-year lead
time provides time to CRS manufacturers that had tested with those
out-of-spec dummies to acquire dummies that meet the necessary
qualifications, and reassess their CRSs as appropriate.
---------------------------------------------------------------------------
In addition, as shown in NHTSA's 2017 testing of CRSs on the SISA
adopted by this final rule, most of the child restraints tested then
did not meet the FMVSS No. 213a performance criteria. These data
indicate a need for CRSs to be re-engineered and reassessed in their
use of side wings, padding and other countermeasures in providing side
impact protection. Further, this final rule specifies that CRSs will
also have to be certified as meeting FMVSS No. 213a when attached by a
Type 2 (lap/shoulder seat belt) in addition to the CRAS. Manufacturers
will need time to assess the performance of their CRSs when attached to
the SISA by way of the belt system, and redesign their restraints with
compliant countermeasures as appropriate.
Lastly, NHTSA has a number of ongoing rulemakings mandated by MAP-
21 for child restraints. In addition to this final rule, as noted
throughout this document MAP-21 directed NHTSA to update the seat
assembly used in the frontal crash test of FMVSS No. 213. MAP-21 also
directed NHTSA to undertake rulemaking to improve the ease of use of
CRAS.\286\ A three-year lead time provides time to manufacturers to
adjust their manufacturing processes to respond to regulatory changes
made by these actions and redesign CRS models, to the extent possible,
within their design cycle to minimize the cost impacts on consumers.
For the reasons explained above, NHTSA finds good cause to have an
effective date of three years following the date of publication in the
Federal Register.\287\
---------------------------------------------------------------------------
\286\ MAP-21, Section 31502. NHTSA published an NPRM on January
23, 2015 (80 FR 3744). The RIN for the rulemaking is 2127-AL20. It
may be tracked in the Unified Agenda of Regulatory and Deregulatory
Actions.
\287\ 49 U.S.C. 30113(d).
---------------------------------------------------------------------------
XI. Regulatory Notices anD Analyses
Executive Order (E.O.) 12866 (Regulatory Planning and Review), E.O.
13563, and DOT Regulatory Policies and Procedures
The agency has considered the impact of this rulemaking action
under E.O. 12866, E.O. 13563, and the Department of Transportation's
regulatory procedures. This rulemaking is considered ``significant''
and was reviewed by the Office of Management and Budget under E.O.
12866, ``Regulatory Planning and Review.'' This final rule amends FMVSS
No. 213 to adopt side impact performance requirements for child
restraint systems designed to seat children in a weight range that
includes weights up to 18.1 kg (40 lb). The requirements are set forth
in FMVSS No. 213a, which specifies that the child restraints meet the
requirements in a dynamic test simulating a vehicle-to-vehicle side
impact. The side impact test of FMVSS No. 213a is additional to the
current frontal impact tests of FMVSS No. 213.
NHTSA has prepared a final regulatory impact analysis (FRIA) that
assesses the cost and benefits of this final rule.\288\ The FRIA
follows a preliminary RIA (PRIA) that was issued in support of the
NPRM. The PRIA evaluated the countermeasures the agency tentatively
determined may be needed for CRSs to meet the proposed performance
requirements, and the benefits of those changes to the target
population (children restrained in a CRS in a side impact). At the time
of the PRIA, NHTSA believed that CRS manufacturers were already
designing CRSs to address side impacts, and that generally only minor
changes in design for forward- and rear-facing child restraints would
be needed to enable child restraints to pass the test proposed in the
NPRM. NHTSA tentatively determined that adding energy-absorbing padding
to the CRS around the head area of the child and to the side structures
(CRS side ``wings'') would likely be sufficient for CRSs to meet the
proposed requirements. Accordingly, NHTSA estimated the costs and
benefits of adding such padding to CRSs and requested comment on the
issue.
---------------------------------------------------------------------------
\288\ The FRIA discusses issues relating to the estimated cost,
benefits, and other impacts of this regulatory action. The FRIA is
available in the docket for this final rule and may be obtained by
downloading it or by contacting Docket Management at the address or
telephone number provided at the beginning of this document.
---------------------------------------------------------------------------
The PRIA determined that the rule would be cost beneficial. NHTSA
estimated that adding padding to the head area and wings of the CRS
would reduce the likelihood of injuries by 3.7 fatalities and 41
injuries when all child restraints sold on the market met the proposed
test criteria limits. These impacts would accrue to an economic benefit
of $168.97 million at a 3 percent discount rate and $152.16 million at
a 7 percent discount rate. NHTSA estimated the cost of the proposed
rule
[[Page 39305]]
at about $7.37 million, with $830,123 of that attributed to the cost of
testing all child restraint models. The countermeasures were estimated
to be larger wings (side structure) and padding with energy-absorption
characteristics that would have a retail cost of approximately $0.58
per CRS.\289\
---------------------------------------------------------------------------
\289\ The agency believed that the cost of a compliance test
(estimated at $1,300) spread over the number of units sold of that
child restraint model was very small, especially when compared to
the price of a child restraint. We estimated that 127 CRS models
comprised the 11.3 million CRSs sold annually for children weighing
up to 40 lb, which have an average model life of 5 years. Therefore,
the annual cost of testing new CRS models was estimated to be
$830,123. This testing cost, distributed among the 11.3 million CRSs
sold annually, amounted to less than $0.01 per CRS.
---------------------------------------------------------------------------
Discussion
As discussed at the beginning of this document, most of the
comments supported the rulemaking proposal but a few did not. Comments
in opposition or expressing concerns (from Dr. Baer, UMTRI and IIHS),
were discussed at length in Section V of this preamble, as was NHTSA's
response to those comments, and will not be repeated here. Several
other individuals did not favor the proposal. Mr. Michael Montalbano
expressed concern about the assumptions NHTSA used for the cost benefit
analysis, stating that the NPRM indicated that 45 percent of child
fatalities ``occurred where the child was not wearing [sic] a CRS'' and
that side crashes resulting in fatalities to children in CRSs mainly
occur in very severe, un-survivable side impact conditions. Mr.
Montalbano asked: ``Will these side impact requirements be effective
given that nearly half of child fatalities occur when CRSs are not
used, and when CRSs are used, most children die from un-survivable side
impact conditions?'' Conversely, a law student group stated that ``even
though the benefits are not extreme, the benefits still outweigh the
comparatively small costs associated with this additional testing.''
In response to Mr. Montalbano, NHTSA's cost benefit analysis
assumes that children who do not use CRSs will not benefit from this
rulemaking, as the standard applies to the CRS products, and does not
require their use. However, as discussed previously, NHTSA is actively
involved in increasing the use of CRSs and the correct use of restraint
systems through other efforts. These efforts include developing and
distributing training videos, producing public safety announcements and
various campaigns directed to caregivers of children (in English,
Spanish and other languages), leveraging all communication resources
(such as social media and the NHTSA website) to provide information to
parents and other caregivers, and expanding and supporting the child
passenger safety technician (CPST) curriculum used to train and certify
CRS fitting station technicians. Also, while this rulemaking does not
directly address the 45 percent of fatalities that occur in very
severe, un-survivable crashes, there may be some circumstances where a
child might benefit from a CRS equipped with side impact protection by
reducing the severity of the injuries in a severe crash.
UMTRI stated that costs involving the purchase of the Q3s ATD, new
instrumentation (IR-TRACC) and buck manufacturing should be included in
cost estimates as this adds to the yearly cost of testing. NHTSA
conducted an analysis \290\ to evaluate the annual cost of owning,
operating, and maintaining the equipment and test devices needed for
conducting the required tests and found that they would be very small
when the costs are spread over the expected lifetime of these equipment
and test devices.
---------------------------------------------------------------------------
\290\ See the Final Regulatory Impact Analysis (FRIA) for more
details on the analysis. The FRIA is available in the docket for
this final rule and may be obtained by downloading it or by
contacting Docket Management at the address or telephone number
provided at the beginning of this document.
---------------------------------------------------------------------------
Dorel stated its concern about a potential overlapping of a side
impact rulemaking with the new FMVSS No. 213 on frontal impact
protection, and the cost impacts of having to produce CRSs to rules
that are introduced at different times. Dorel explained that it would
need to evaluate the costs of a side impact test along any new proposed
frontal impact test in conjunction with a new side impact test to fully
comment on a cost analysis, and that without testing data of both side
impact and frontal impact tests it could only estimate in broad terms
at that time. Dorel added that in terms of redesign, retooling, and
manufacturing startup costs, such an undertaking can range from product
modification to product obsolescence. Dorel explained that a single
ground up project of a single platform for a single set of tooling can
range anywhere from $1.5-$2.5 million and that multiples of tooling can
range $500 thousand upward to $1.5 million depending on the type and
design of CRS. Dorel added that manufacturers would have to increase
resources in a very short time and that typical development times from
start to production in mass quantity could range from 18-24 months.
Dorel argued that this could pose a major disruption of supply meeting
customer demand, and that it prefers a synchronization of both
standards so as to afford the design and development process and costs
to consolidate to meet both new regulations.
In response to Dorel, we note that both this side impact final rule
and a final rule upgrading the frontal impact seat assembly of FMVSS
No. 213 (see NPRM, 85 FR 69388) are mandated by MAP-21. Nonetheless,
while we believe the new side impact requirements adopted in this final
rule will result in design changes to the CRS designs, NHTSA does not
believe that the frontal impact changes will necessitate extensive CRS
design changes as it appears most CRSs already meet the proposed rule's
substantive requirements. (Some labeling changes may be needed.)
Further, once NHTSA knows the timing of the frontal upgrade final rule,
NHTSA will keep Dorel's concerns in mind to see if adjusting lead times
would be appropriate and consistent with the Safety Act.
In developing the 2014 NPRM, NHTSA considered HIC15 requirements of
400 and 800 as alternatives to the preferred proposal of HIC15 of 570.
The PRIA for the NPRM provided an assessment of benefits and costs of
the HIC15 of 400 and 800 alternatives. Of the alternatives presented
for HIC15, NHTSA has decided in this final rule on its preferred
alternative of 570. This threshold value achieves a reasonable balance
of practicability, safety, and cost. The HIC15 threshold of 570 is used
in FMVSS No. 208, ``Occupant crash protection,'' for the 3-year-old
child dummy. It is a scaled threshold based on FMVSS No. 208's
criterion for the 50th percentile adult male dummy, which was adjusted
to the 3-year-old using a process that accounts for differences in
geometric size and material strength. HIC15 of 570 corresponds to an 11
percent risk of AIS 3+ injury and a 1.6 percent risk of fatality. The
570 scaled maximum will protect children in child restraints from an
unreasonable risk of fatality and serious injury in side impacts.
Comparing the three alternatives (at the 7 percent discount rate),
an 800 HIC15 limit results in: (a) many fewer equivalent lives saved
than the 570 HIC15 limit (7.24 vs. 18.26); (b) higher cost per
equivalent life saved ($488,000 vs. $242,000); and, (c) lower net
benefits ($63 million vs. $162 million). Thus, on all three measures,
800 HIC15 achieves fewer NHTSA goals as compared to the 570 HIC15.
The 400 HIC15 alternative results in: (a) more equivalent lives
saved than the 570 HIC15 limit (28.87 vs. 18.26); higher cost per
equivalent life saved ($314,000 vs. $242,000); and, (c) higher net
[[Page 39306]]
benefits ($250 million vs. $162 million). Thus, on two of the three
measures, at first glance 400 HIC15 has appeal compared to the 570
HIC15 limit.
However, NHTSA is concerned about the effect of a 400 HIC15 limit
on child restraint design and use and did not have information to
address those concerns sufficiently. The agency is concerned that the
cost estimates utilized may not take into account changes necessary to
meet the 400 HIC15 limit. We believe that padding alone would be
insufficient to meet a 400 HIC15 limit, and that a structural
improvement to the side of the seats would be needed in addition to
padding. We did not receive data on which to determine what structural
or other changes would be needed to meet a 400 HIC15 reference, or
whether the structural modifications can be implemented to meet the 400
HIC15 criterion at the cost we assumed.
Moreover, NHTSA is concerned that one method of potential
compliance with a 400 HIC15 limit could cause unintended negative
consequences not assessed in our estimate of costs. We believe that
manufacturers could possibly increase padding to meet a 400 HIC15
limit. Thicker padding around the head area could reduce the space
provided for the child's head, which may make the child restraint
uncomfortable and confining for the child. The restricted space for the
child's head could reduce the ability of the seated child to move his
or her head freely, which could affect acceptability and use of the
harness-equipped age-appropriate child restraints. Alternatively, if
manufacturers decided to increase the thickness of the padding in the
head area and widen the CRS to retain the current space between the
child's head and side padding, the child restraint would have to be
made wider and heavier. Again, this might affect the overall use of the
child restraint. Considering all of these factors, NHTSA has chosen 570
HIC15 as the best overall reference value with known consequences that
can be met with a reasonable thickness of padding alone.
This final rule reduces 3.7 fatalities and 41 (40.9) serious non-
fatal injuries (MAIS \291\ 4-5) annually (see Table 26 below).\292\ The
equivalent lives and the monetized benefits were estimated in
accordance with guidance issued March 2021 by the Office of the
Secretary \293\ regarding the treatment of value of a statistical life
in regulatory analyses. This final rule is estimated to save 15.1
equivalent lives annually. The monetized annual benefits of the rule at
3 and 7 percent discount rates are $169.0 million and $152.1 million,
respectively (Table 27). The annual cost of this final rule is
estimated at approximately $7.37 million. The countermeasures may
include larger wings and padding with energy absorption characteristics
that cost, on average, approximately $0.58 per CRS designed for
children in a weight range that includes weights up to 40 lb (both
forward-facing and rear-facing) (Table 28 below). The annual net
benefits are estimated to be $144.8 million (7 percent discount rate)
to $161.6 million (3 percent discount rate) as shown in Table 29.
Because the rule is cost beneficial just by comparing costs to
monetized economic benefits, and there is a net benefit, it is
unnecessary to provide a net cost per equivalent life saved since no
value would be provided by such an estimate.
---------------------------------------------------------------------------
\291\ MAIS (Maximum Abbreviated Injury Scale) represents the
maximum injury severity of an occupant based on the Abbreviated
Injury Scale (AIS). AIS ranks individual injuries by body region on
a scale of 1 to 6: 1=minor, 2=moderate, 3=serious, 4=severe,
5=critical, and 6=maximum (untreatable). MAIS 3+ injuries represent
MAIS injuries at an AIS level of 3, 4, 5, or 6.
\292\ NHTSA has developed a Final Regulatory Impact Analysis
(FRIA) that discusses issues relating to the estimated costs,
benefits, and other impacts of this regulatory action. The FRIA is
available in the docket for this final rule and may be obtained by
downloading it or by contacting Docket Management at the address or
telephone number provided at the beginning of this document.
\293\ http://www.dot.gov/sites/dot.dev/files/docs/VSL%20Guidance%202013.pdf
Table 26--Estimated Benefits
------------------------------------------------------------------------
------------------------------------------------------------------------
Fatalities.............................................. 3.7
Non-fatal injuries (MAIS 1 to 5)........................ 41 (40.9)
------------------------------------------------------------------------
Table 27--Estimated Monetized Benefits
[In millions of 2020 dollars]
----------------------------------------------------------------------------------------------------------------
Value of
Economic statistical Total benefits
benefits life
----------------------------------------------------------------------------------------------------------------
3 Percent Discount Rate......................................... $26.24 $142.72 $168.97
7 Percent Discount Rate......................................... 23.63 128.53 152.16
----------------------------------------------------------------------------------------------------------------
Table 28--Estimated Costs (2020 Economics)
------------------------------------------------------------------------
------------------------------------------------------------------------
Average cost per CRS designed for children in a weight $0.58
range that includes weights up to 40 lb................
------------------------------------------------------------------------
Total incremental CRS cost.......................... 6.54 million
Testing costs........................................... 830,123
------------------------------------------------------------------------
Total annual cost................................... 7.37 million
------------------------------------------------------------------------
Table 29--Annualized Costs and Benefits
[In millions of 2020 dollars]
----------------------------------------------------------------------------------------------------------------
Annualized Annualized
costs benefits Net benefits
----------------------------------------------------------------------------------------------------------------
3% Discount Rate................................................ $7.37 $168.97 $161.60
7% Discount Rate................................................ 7.37 152.16 144.79
----------------------------------------------------------------------------------------------------------------
[[Page 39307]]
Regulatory Flexibility Act
Pursuant to the Regulatory Flexibility Act (5 U.S.C. 601 et seq.,
as amended by the Small Business Regulatory Enforcement Fairness Act
(SBREFA) of 1996) whenever an agency is required to publish a notice of
proposed rulemaking or final rule, it must prepare and make available
for public comment a regulatory flexibility analysis that describes the
effect of the rule on small entities (i.e., small businesses, small
organizations, and small governmental jurisdictions), unless the head
of an agency certifies the rule will not have a significant economic
impact on a substantial number of small entities. Agencies must also
provide a statement of the factual basis for this certification.
I certify that this final rule would not have a significant
economic impact on a substantial number of small entities. NHTSA
estimates there to be 29 manufacturers of child restraints, none of
which are small businesses. Based on our fleet testing, we believe that
most of the CRSs that are subject to the side impact requirements will
meet the requirements without substantial modification. For rear-facing
infant seats and forward-facing restraints with harnesses that need to
be modified, the agency estimates that the average incremental costs to
each child restraint system would be only $0.58 per unit to meet this
final rule. This incremental cost will not constitute a significant
economic impact. Further, the incremental cost is not significant
compared to the retail price of a child restraint system for infants
and toddlers, which is in the range of $45 to $350.
For belt-positioning seats that will not be able to meet the side
impact requirements adopted by this final rule, the simplest course for
a manufacturer will be to re-label the restraint prior to introduction
into interstate commerce so that it is marketed for children not in a
weight class that will subject the CRS to the rule's requirements. That
is, the CRSs could be marketed as belt-positioning seats for children
weighing more than 18.1 kg (40 lb), instead of for children weighing
above 13.6 kg (30 lb).\294\
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\294\ Currently, FMVSS No. 213 prohibits manufacturers from
recommending belt-positioning seats for children weighing less than
13.6 kg (30 lb). NHTSA has proposed increasing this weight limit to
18.1 kg (40 lb) (85 FR 69388). If adopted, the weight threshold
would also have the effect of excluding booster seats from the
application of FMVSS No. 213a.
---------------------------------------------------------------------------
The agency believes that the cost of conducting the test described
in this final rule (estimated at $1,543) spread over the number of
units sold of that child restraint model will be very small, especially
when compared to the price of a child restraint. We estimate that 127
CRS models comprise the 11.3 million CRSs that include recommended
weights for children weighing up to 40 pounds. The average model life
is estimated to be 5 years. Therefore, we estimate that, assuming
manufacturers will be conducting the dynamic test specified in this
final rule to certify their child restraints to the new side impact
requirements, the annual cost of testing new CRS models will be
$830,123. This testing cost, distributed among the 11.3 million CRSs
sold annually with an average model life of 5 years, will be less than
$0.01 per CRS.
National Environmental Policy Act
NHTSA has analyzed this final rule for the purposes of the National
Environmental Policy Act and determined that it will not have any
significant impact on the quality of the human environment.
Executive Order 13132 (Federalism)
NHTSA has examined this final rule pursuant to Executive Order
13132 (64 FR 43255, August 10, 1999) and concluded that no additional
consultation with States, local governments or their representatives is
mandated beyond the rulemaking process. The agency has concluded that
the rulemaking will not have sufficient federalism implications to
warrant consultation with State and local officials or the preparation
of a federalism summary impact statement. The final rule will not have
``substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government.''
NHTSA rules can preempt in two ways. First, the National Traffic
and Motor Vehicle Safety Act contains an express preemption provision:
When a motor vehicle safety standard is in effect under this chapter, a
State or a political subdivision of a State may prescribe or continue
in effect a standard applicable to the same aspect of performance of a
motor vehicle or motor vehicle equipment only if the standard is
identical to the standard prescribed under this chapter. 49 U.S.C.
Section 30103(b)(1). It is this statutory command by Congress that
preempts any non-identical State legislative and administrative law
addressing the same aspect of performance. The express preemption
provision described above is subject to a savings clause under which
``[c]ompliance with a motor vehicle safety standard prescribed under
this chapter does not exempt a person from liability at common law.''
49 U.S.C. Section 30103(e). Pursuant to this provision, State common
law tort causes of action against motor vehicle manufacturers that
might otherwise be preempted by the express preemption provision are
generally preserved.
However, the Supreme Court has recognized the possibility, in some
instances, of implied preemption of such State common law tort causes
of action by virtue of NHTSA's rules, even if not expressly preempted.
This second way that NHTSA rules can preempt is dependent upon there
being an actual conflict between an FMVSS and the higher standard that
would effectively be imposed on motor vehicle manufacturers if someone
obtained a State common law tort judgment against the manufacturer,
notwithstanding the manufacturer's compliance with the NHTSA standard.
Because most NHTSA standards established by an FMVSS are minimum
standards, a State common law tort cause of action that seeks to impose
a higher standard on motor vehicle manufacturers will generally not be
preempted. However, if and when such a conflict does exist--for
example, when the standard at issue is both a minimum and a maximum
standard--the State common law tort cause of action is impliedly
preempted. See Geier v. American Honda Motor Co., 529 U.S. 861 (2000).
Pursuant to Executive Order 13132 and 12988, NHTSA has considered
whether this final rule could or should preempt State common law causes
of action. The agency's ability to announce its conclusion regarding
the preemptive effect of one of its rules reduces the likelihood that
preemption will be an issue in any subsequent tort litigation. To this
end, the agency has examined the nature (e.g., the language and
structure of the regulatory text) and objectives of this final rule and
finds that this rule, like many NHTSA rules, would prescribe only a
minimum safety standard. As such, NHTSA does not intend this final rule
to preempt state tort law that would effectively impose a higher
standard on motor vehicle manufacturers than that established by this
final rule. Establishment of a higher standard by means of State tort
law will not conflict with the minimum standard adopted here. Without
any conflict, there could not be any implied preemption of a State
common law tort cause of action.
Civil Justice Reform
With respect to the review of the promulgation of a new regulation,
section 3(b) of Executive Order 12988,
[[Page 39308]]
``Civil Justice Reform'' (61 FR 4729, February 7, 1996) requires that
Executive agencies make every reasonable effort to ensure that the
regulation: (1) Clearly specifies the preemptive effect; (2) clearly
specifies the effect on existing Federal law or regulation; (3)
provides a clear legal standard for affected conduct, while promoting
simplification and burden reduction; (4) clearly specifies the
retroactive effect, if any; (5) adequately defines key terms; and (6)
addresses other important issues affecting clarity and general
draftsmanship under any guidelines issued by the Attorney General. This
document is consistent with that requirement.
Pursuant to this Order, NHTSA notes as follows. The preemptive
effect of this final rule is discussed above. NHTSA notes further that
there is no requirement that individuals submit a petition for
reconsideration or pursue other administrative proceeding before they
may file suit in court.
Paperwork Reduction Act (PRA)
Under the PRA of 1995, a person is not required to respond to a
collection of information by a Federal agency unless the collection
displays a valid OMB control number. There are no ``collections of
information'' (as defined at 5 CFR 1320.3(c)) in this final rule.
National Technology Transfer and Advancement Act
Under the National Technology Transfer and Advancement Act of 1995
(NTTAA) (Pub. L. 104-113), all Federal agencies and departments shall
use technical standards that are developed or adopted by voluntary
consensus standards bodies, using such technical standards as a means
to carry out policy objectives or activities determined by the agencies
and departments. Voluntary consensus standards are technical standards
(e.g., materials specifications, test methods, sampling procedures, and
business practices) that are developed or adopted by voluntary
consensus standards bodies, such as the International Organization for
Standardization (ISO) and the Society of Automotive Engineers (SAE).
The NTTAA directs us to provide Congress, through OMB, explanations
when we decide not to use available and applicable voluntary consensus
standards.
As explained above in this preamble and in the January 28, 2014
NPRM preceding this final rule, NHTSA reviewed the procedures and
regulations developed globally to dynamically test child restraints in
the side impact environment. Except for the Takata test procedure, the
procedures and regulations did not replicate all of the dynamic
elements of a side crash that we sought to include in the side impact
test, or were not sufficiently developed for further consideration.
NHTSA considered AS/NZS 1754 for implementation into FMVSS No. 213
but did not find it acceptable. The test does not simulate an intruding
door, which is an important component in the side impact environment.
In addition, AS/NZS 1754 does not account for a longitudinal component,
which we also believe is an important characteristic of a side crash.
(As noted above, NHTSA's 2002 ANPRM, supra, was based on AS/NZS 1754.
Commenters to the ANPRM believed that a dynamic test should account for
some degree of vehicle intrusion into the occupant compartment.)
Australia's CREP test also was limited by its lack of an intruding
door, which is a component that is important in the side impact
environment.
Test procedures from other countries and entities were also too
limited. Germany's ADAC test procedure lacks an intruding door. While
the ISO/TNO test procedure accounts for the deceleration and intrusion
experienced by a car in a side impact crash, one of its limitations is
that the angular velocity of the hinged door is difficult to control,
which results in poor repeatability. In addition, these methods do not
include a longitudinal velocity component to the intruding door, which
is present in most side impacts and which NHTSA sought to replicate in
the FMVSS No. 213a test. NHTSA considered the EU's test procedure but
decided not to pursue it, since the test is of lower severity than the
crash conditions the agency sought to replicate and of lower severity
than the FMVSS No. 214 MDB side impact crash test of a small passenger
vehicle. Moreover, the test procedure is only intended for evaluating
CRSs with rigid ISOFIX attachments, which are not prevalent in the U.S.
Further, the sliding anchors do not seem to produce a representative
interaction between the door and CRS during a side impact, and may
introduce variability in the test results.
NPACS completed a test procedure in 2006. The NPACS final approach
is comparable to the International Standards Organization (ISO) side
impact efforts which include a rotating hinged door to simulate door
intrusion into the CRS. As discussed in the NPRM, the rotating hinged
door procedures account for the deceleration and intrusion experienced
by a car in a side impact crash but one of its limitations is that the
angular velocity of the hinged door is difficult to control resulting
in poor repeatability.\295\ In addition, these methods do not include a
longitudinal velocity component to the intruding door, which is present
in most side impact crashes. The NPACS procedure also specifies a sled
velocity change corridor with a longer duration than desired. NHTSA
found that for a small vehicle FMVSS No. 214 MDB test, the change in
velocity duration was between 40-50 milliseconds, while NPACS has a
duration of 70-75 milliseconds. While the agency did not evaluate these
procedures, the agency did not find them compelling enough to pursue or
change from the selected Takata sled-on-sled method, which has proven
to be repeatable and reproducible and can be adapted to be done in an
acceleration type or a deceleration type sled system.
---------------------------------------------------------------------------
\295\ Sandner, V., Ratzek, A., Kolke, R., Kraus, W., Lang, M.
``New Programm for the assessment of child restraint systems
(NPACS)--Development/research/results--First step for future
activities?'' Paper Number 09-0298.
---------------------------------------------------------------------------
NHTSA based the side impact test on a test procedure that was
developed in the industry. In so doing, NHTSA saved agency resources by
making use of pertinent technical information that was already
available. This effort to save resources is consistent with the NTTAA's
goal of reducing when possible the agency's cost of developing its own
standards.
Unfunded Mandates Reform Act
Section 202 of the Unfunded Mandates Reform Act of 1995 (UMRA),
Public Law 104-4, requires Federal agencies to prepare a written
assessment of the costs, benefits, and other effects of proposed or
final rules that include a Federal mandate likely to result in the
expenditure by State, local, or tribal governments, in the aggregate,
or by the private sector, of more than $100 million annually (adjusted
for inflation with base year of 1995). Adjusting this amount by the
implicit gross domestic product price deflator for the year 2020
results in $158 million (113.635/71.868 = 1.581). This final rule does
not result in a cost of $158 million or more to either State, local, or
tribal governments, in the aggregate, or the private sector. Thus, this
rule is not subject to the requirements of sections 202 of the UMRA.
Executive Order 13609 (Promoting International Regulatory Cooperation)
The policy statement in section 1 of E.O. 13609 provides, in part:
The regulatory approaches taken by foreign governments may
differ from those taken by
[[Page 39309]]
U.S. regulatory agencies to address similar issues. In some cases,
the differences between the regulatory approaches of U.S. agencies
and those of their foreign counterparts might not be necessary and
might impair the ability of American businesses to export and
compete internationally. In meeting shared challenges involving
health, safety, labor, security, environmental, and other issues,
international regulatory cooperation can identify approaches that
are at least as protective as those that are or would be adopted in
the absence of such cooperation. International regulatory
cooperation can also reduce, eliminate, or prevent unnecessary
differences in regulatory requirements.
NHTSA requested public comment on the ``regulatory approaches taken
by foreign governments'' concerning the subject matter of this
rulemaking but received no comments on this issue. In the discussion
above on the NTTAA, we explained that we reviewed the procedures and
regulations developed globally to test child restraints dynamically in
the side impact environment and found the Takata test procedure to be
the most suitable for our purposes.
Incorporation by Reference
Under regulations issued by the Office of the Federal Register (1
CFR 51.5(a)), an agency, as part of a final rule that includes material
incorporated by reference, must summarize in the preamble of the final
rule the material it incorporates by reference and discuss the ways the
material is reasonably available to interested parties or how the
agency worked to make materials available to interested parties.
In this final rule, NHTSA incorporates by reference material
entitled, ``Parts List and Drawings, NHTSA Standard Seat Assembly;
FMVSS No. 213a--Side impact No. NHTSA-213a-2021, CHILD SIDE IMPACT
SLED,'' dated December 2021, that consists of engineering drawings and
specifications for the side impact seat assembly (SISA) that NHTSA will
use to assess the compliance of child restraints with Standard No.
213a. The SISA consists of a sliding seat, with one seating position,
and a simulated door assembly.
NHTSA has placed a copy of the material in the docket for this
final rule. Interested persons can download a copy of the material or
view the material online by accessing www.Regulations.gov, telephone 1-
877-378-5457, or by contacting NHTSA's Chief Counsel's Office at the
phone number and address set forth in the FOR FURTHER INFORMATION
section of this document. The material is also available for inspection
at the Department of Transportation, Docket Operations, Room W12-140,
1200 New Jersey Avenue SE, Washington, DC, Telephone: 202-366-9826.
This final rule also incorporates SAE Recommended Practice J211/1,
revised March 1995, ``Instrumentation for Impact Tests-Part 1--
Electronic Instrumentation,'' This SAE standard is already incorporated
in 49 CFR 571.5(l)(4). The SAE J211/1 standard provides guidelines and
recommendations for techniques of measurements used in impact tests to
achieve uniformity in instrumentation practice and in reporting
results. Signals from impact tests have to be filtered following the
standard's guidelines to eliminate noise from sensor signals. Following
J211/1 guidelines provides a basis for meaningful comparisons of test
results from different sources. The SAE material is available for
review at NHTSA and is available for purchase from SAE International.
Formatting
Note: Due to new Federal Register formatting guidelines, the
``figure number and title'' labels in the regulatory text now appear
directly above the corresponding figure instead of below the
corresponding figure.
Regulation Identifier Number
The Department of Transportation assigns a regulation identifier
number (RIN) to each regulatory action listed in the Unified Agenda of
Federal Regulations. The Regulatory Information Service Center
publishes the Unified Agenda in April and October of each year. You may
use the RIN contained in the heading at the beginning of this document
to find this action in the Unified Agenda.
Plain Language
Executive Order 12866 requires each agency to write all rules in
plain language. Application of the principles of plain language
includes consideration of the following questions:
Have we organized the material to suit the public's needs?
Are the requirements in the rule clearly stated?
Does the rule contain technical language or jargon that
isn't clear?
Would a different format (grouping and order of sections,
use of headings, paragraphing) make the rule easier to understand?
Would more (but shorter) sections be better?
Could we improve clarity by adding tables, lists, or
diagrams?
What else could we do to make the rule easier to
understand?
If you have any responses to these questions, please write to us
with your views.
List of Subjects in 49 CFR Part 571
Imports, Motor vehicle safety, Motor vehicles, and Tires;
Incorporation by reference.
In consideration of the foregoing, NHTSA amends 49 CFR part 571 as
set forth below.
PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS
0
1. The authority citation for Part 571 continues to read as follows:
Authority: 49 U.S.C. 322, 30111, 30115, 30117 and 30166;
delegation of authority at 49 CFR 1.95.
0
2. Section 571.5 is amended by:
0
a. Revising paragraph (a);
0
b; Adding paragraph (k)(5);
0
c. Revising paragraph (l)(4); and
0
d. In addition to the previous amendments, remove the text ``http://''
and add in its place the text ``https://'' wherever it appears
throughout this section.
The revisions and addition read as follows:
Sec. 571.5 Matter incorporated by reference.
(a) Certain material is incorporated by reference into this part
with the approval of the Director of the Federal Register in accordance
with 5 U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other
than that specified in this section, the National Highway Traffic
Safety Administration (NHTSA) must publish a document in the Federal
Register and the material must be available to the public. All approved
incorporation by reference (IBR) material is available for inspection
at NHTSA and at the National Archives and Records Administration
(NARA). Contact NHTSA at: NHTSA, 1200 New Jersey Avenue SE, Washington,
DC 20590, (202) 366-2588, website: https://www.nhtsa.gov/about-nhtsa/electronic-reading-room. For information on the availability of this
material at NARA, email: [email protected], or go to:
www.archives.gov/federal-register/cfr/ibr-locations.html. The material
may be obtained from the sources in the following paragraphs of this
section.
* * * * *
(k) * * *
(5) ``Parts List and Drawings, NHTSA Standard Seat Assembly; FMVSS
No. 213a--Side impact No. NHTSA-213a-2021, CHILD SIDE IMPACT SLED''
dated December 2021; into Sec. 571.213a.
(l) * * *
(4) SAE Recommended Practice J211/1, ``Instrumentation for Impact
Tests-
[[Page 39310]]
Part 1--Electronic Instrumentation''; revised March 1995; into
Sec. Sec. 571.202a; 571.208; 571.213a; 571.218; 571.403.
* * * * *
0
3. Section 571.213 is amended by adding paragraph S5(g) to read as
follows:
Sec. 571.213 Standard No. 213; Child restraint systems.
* * * * *
S5 * * *
(g) Each add-on child restraint system manufactured for use in
motor vehicles, that is recommended for children in a weight range that
includes weights up to 18 kilograms (40 pounds), or for children in a
height range that includes heights up to 1100 millimeters, shall meet
the requirements in this standard and the additional side impact
protection requirements in Standard No. 213a (Sec. 571.213a). Excepted
from Standard No. 213a are harnesses and car beds.
* * * * *
0
4. Section 571.213a is added to read as follows:
Sec. 571.213a Standard No. 213a; Child restraint systems--side impact
protection.
S1. Scope. This standard specifies side impact protection
requirements for child restraint systems recommended for children in a
weight range that includes weights up to 18 kilograms (40 pounds) or by
children in a height range that includes heights up to 1100 millimeters
(43 inches).
S2. Purpose. The purpose of this standard is to reduce the number
of children killed or injured in motor vehicle side impacts. Each child
restraint system subject to this standard shall also meet all
applicable requirements in FMVSS No. 213 (Sec. 571.213).
S3. Application. This standard applies to add-on child restraint
systems that are either recommended for use by children in a weight
range that includes weights up to 18 kilograms (40 pounds) regardless
of height, or by children in a height range that includes heights up to
1100 millimeters regardless of weight, except for car beds and
harnesses.
S4. Definitions.
Add-on child restraint system means any portable child restraint
system.
Belt-positioning seat means a child restraint system that positions
a child on a vehicle seat to improve the fit of a vehicle Type II belt
system on the child and that lacks any component, such as a belt system
or a structural element, designed to restrain forward movement of the
child's torso in a forward impact.
Car bed means a child restraint system designed to restrain or
position a child in the supine or prone position on a continuous flat
surface.
Child restraint anchorage system is defined in S3 of FMVSS No. 225
(Sec. 571.225).
Child restraint system is defined in S4 of FMVSS No. 213 (Sec.
571.213).
Contactable surface means any child restraint system surface (other
than that of a belt, belt buckle, or belt adjustment hardware) that may
contact any part of the head or torso of the appropriate test dummy,
specified in S7, when a child restraint system is tested in accordance
with S6.1.
Harness means a combination pelvic and upper torso child restraint
system that consists primarily of flexible material, such as straps,
webbing or similar material, and that does not include a rigid seating
structure for the child.
Rear-facing child restraint system means a child restraint system
that positions a child to face in the direction opposite to the normal
(forward) direction of travel of the motor vehicle.
Seat orientation reference line or SORL means the horizontal line
through Point Z as illustrated in Figure 1 to Sec. 571.213a.
Tether anchorage is defined in S3 of FMVSS No. 225 (Sec. 571.225).
Tether strap is defined in S3 of FMVSS No. 225 (Sec. 571.225).
Torso means the portion of the body of a seated anthropomorphic
test dummy, excluding the thighs, that lies between the top of the
child restraint system seating surface and the top of the shoulders of
the test dummy.
S5. Requirements. (a) Each child restraint system subject to this
section shall meet the requirements in this section when, as specified,
tested in accordance with S6 and this paragraph. Each child restraint
system shall meet the requirements when oriented in each direction
recommended by the manufacturer (i.e., forward, rearward), using any of
the seat back angle adjustment positions and restraint belt routing
positions designated for that direction, pursuant to S5.6 of FMVSS No.
213 (Sec. 571.213), and tested with the test dummy specified in S7 of
this section.
(b) Each child restraint system subject to this section shall also
meet all applicable requirements in FMVSS No. 213 (Sec. 571.213).
S5.1 Dynamic performance.
S5.1.1 Child restraint system integrity. When tested in accordance
with S6.1, each child restraint system shall meet the requirements of
paragraphs (a) through (c) of this section.
(a) With any padding or other flexible overlay material removed,
exhibit no complete separation of any load bearing structural element
and no partial separation exposing either surfaces with a radius of
less than 6 millimeters or surfaces with protrusions greater than 9
millimeters above the immediate adjacent surrounding contactable
surface of any structural element of the child restraint system.
(b)(1) If adjustable to different positions, remain in the same
adjustment position during the testing that it was in immediately
before the testing, except as otherwise specified in paragraph (b)(2).
(2)(i) Subject to paragraph (b)(2)(ii), a rear-facing child
restraint system may have a means for repositioning the seating surface
of the system that allows the system's occupant to move from a reclined
position to an upright position and back to a reclined position during
testing.
(ii) No opening that is exposed and is larger than 6 millimeters
before the testing shall become smaller during the testing as a result
of the movement of the seating surface relative to the child restraint
system as a whole.
(c) If a front facing child restraint system, not allow the angle
between the system's back support surfaces for the child and the
system's seating surface to be less than 45 degrees at the completion
of the test.
S5.1.2 Injury criteria. When tested in accordance with S6.1 and
with the test dummy specified in S7, each child restraint system that,
in accordance with S5.5.2 of Standard No. 213 (Sec. 571.213), is
recommended for use by children whose mass is more than 13.6 kilograms
or whose height is more than 870 mm shall--
(a) Limit the resultant acceleration at the location of the
accelerometer mounted in the test dummy head as specified in Part 572
such that, for any two points in time, t1 and t2, during the event
which are separated by not more than a 15 millisecond time interval and
where t1 is less than t2, the maximum calculated head injury criterion
(HIC) shall not exceed 570, determined using the resultant head
acceleration at the center of gravity of the dummy head, ar,
expressed as a multiple of g (the acceleration of gravity), calculated
using the expression:
[[Page 39311]]
[GRAPHIC] [TIFF OMITTED] TR30JN22.017
(b) The maximum chest compression (or deflection) from the output
of the thoracic InfraRed Telescoping Rod for Assessment of Chest
Compression (IR-TRACC) shall not exceed 23 millimeters.
S5.1.3 Occupant containment. When tested in accordance with S6.1
and the requirements specified in this section, each child restraint
system recommended for use by children in a specified mass range that
includes any children having a mass greater than 5 kilograms but not
greater than 13.6 kilograms (30 lb), shall retain the test dummy's head
such that there is no direct contact of the head to any part of the
side impact seat assembly described in S6.1.1(a).
S5.1.4 Protrusion limitation. Any portion of a rigid structural
component within or underlying a contactable surface shall, with any
padding or other flexible overlay material removed, have a height above
any immediately adjacent restraint system surface of not more than 9
millimeters and no exposed edge with a radius of less than 6
millimeters.
S5.1.5 Belt buckle release. Any buckle in a child restraint system
belt assembly designed to restrain a child using the system shall:
(a) When tested in accordance with the appropriate sections of
S6.2, after the dynamic test of S6.1, release when a force of not more
than 71 Newtons is applied.
(b) Not release during the testing specified in S6.1.
S5.1.6 Installation. Each add-on child restraint system shall be
capable of meeting the requirements of this standard when installed
solely by each of the means indicated in the following table:
Table 1 to S5.1.6
--------------------------------------------------------------------------------------------------------------------------------------------------------
Means of installation
-------------------------------------------------------------------------------------------
Lower anchorages of
Type of add-on child restraint system Type II seat belt Lower anchorages of the child restraint
Type II seat belt assembly plus a the child restraint anchorage system
assembly tether if needed anchorage system plus a tether if
needed
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rear-facing restraints...................................... X ..................... X .....................
Forward-facing restraints................................... ..................... X ..................... X
--------------------------------------------------------------------------------------------------------------------------------------------------------
S6. Test conditions and procedures.
S6.1 Dynamic side impact test for child restraint systems. The test
conditions and test procedure for the dynamic side impact test are
specified in S6.1.1 and S6.1.2, respectively.
S6.1.1 Test conditions.
(a) Test device. (1) The test device is a side impact seat assembly
(SISA) consisting of a sliding seat, with one seating position, and a
simulated door assembly as described in ``NHTSA Standard Seat Assembly;
FMVSS No. 213a--Side impact No. NHTSA-213a-2021'' (incorporated by
reference, see Sec. 571.5). The simulated door assembly is rigidly
attached to the floor of the SISA and the sliding seat is mounted on
rails to allow it to move relative to the floor of the SISA in the
direction perpendicular to the SORL. The SISA is mounted on a dynamic
test platform so that the SORL of the seat is 10 +/-0.1 degrees from
the perpendicular direction of the test platform travel.
(2) As illustrated in the SISA drawing package, attached to the
seat belt anchorage points provided on the SISA is a Type II seat belt
assembly. These seat belt assemblies are certified to meet the
requirements of Standard No. 209 (Sec. 571.209) and have webbing with
a width of not more than 2 inches, and are attached to the anchorage
points without the use of retractors or reels of any kind. As
illustrated in the SISA drawing package, attached to the SISA is a
child restraint anchorage system conforming to the specifications of
Standard No. 225 (Sec. 571.225).
(b) Accelerate the test platform to achieve a relative velocity of
31.3 0.64 km/h in the direction perpendicular to the SORL
between the SISA sliding seat and the door assembly at the time they
come in contact (time = T0). The front face of the armrest
on the door is 38 6 millimeters from the edge of the seat
towards the SORL at time = T0. The test platform velocity in
the direction perpendicular to the SORL during the time of interaction
of the door with the child restraint system is no lower than 2.5 km/h
less than its velocity at time = T0.
(c) The sliding seat acceleration perpendicular to the SORL is any
pulse within the acceleration corridor shown in Figure 3 and the change
in relative velocity perpendicular to the SORL between the SISA sliding
seat and the door assembly is any velocity within the relative velocity
corridor shown in Figure 4.
(d) Performance tests under S6.1 are conducted at any ambient
temperature from 20.6 [deg]C to 22.2 [deg]C and at any relative
humidity from 10 percent to 70 percent.
(e) The child restraint shall meet the requirements of S5 when
oriented in each direction recommended by the manufacturer (i.e.,
forward, rearward), using any of the seat back angle adjustment
positions and restraint belt routing positions designated for that
direction, pursuant to S5.6 of FMVSS No. 213 (Sec. 571.213), and
tested with the test dummy specified in S7 of this section.
S6.1.2 Dynamic test procedure.
(a) The child restraint centerline is positioned 300 2
millimeters from the SISA sliding seat edge (impact side). The child
restraint system is attached in any of the following manners, at
NHTSA's option.
(1) Install the child restraint system using the child restraint
anchorage system in accordance with the manufacturer's instructions
provided with the child restraint system pursuant to S5.6 of Standard
No. 213 (Sec. 571.213),
[[Page 39312]]
except as provided in this paragraph. For forward-facing restraints,
attach the tether strap, if provided, to the tether anchorage on the
SISA. No supplemental device is used to install the child restraint
system. Tighten belt systems of the lower anchorage attachments used to
attach the restraint to the SISA sliding seat to any tension of not
less than 53.5 Newtons and not more than 67 Newtons. Tighten the belt
of the top tether attachment used to attach the restraint to the SISA
sliding seat to any tension of not less than 45 Newtons and not more
than 53.5 Newtons.
(2) For forward-facing and rear-facing child restraint systems,
install the child restraint system using the Type II belt system in
accordance with the manufacturer's instructions provided with the child
restraint system pursuant to S5.6 of Standard No. 213 (Sec. 571.213),
except as provided in this paragraph. For forward-facing restraints,
attach the top tether strap, if provided, to the top tether anchorage
on the SISA. For all child restraints, no supplemental device to
install the child restraint system is used. Tighten the Type II belt
used to attach the restraint to the SISA sliding seat to any tension of
not less than 53.5 Newtons and not more than 67 Newtons. Tighten the
belt of the top tether attachment used to attach the forward-facing
restraint to the SISA sliding seat to any tension of not less than 45
Newtons and not more than 53.5 Newtons. Rear-facing infant carriers
with a detachable base shall only be tested using the base.
(3) For rear-facing restraints, install the child restraint system
using only the lower anchorages of the child restraint anchorage system
in accordance with the manufacturer's instructions provided with the
child restraint system pursuant to S5.6 of Standard No. 213 (Sec.
571.213). No tether strap is used. No supplemental device is used to
install the child restraint system. Tighten belt systems used to attach
the restraint to the SISA-sliding seat to any tension of not less than
53.5 Newtons and not more than 67 Newtons. Rear-facing infant carriers
with a detachable base shall only be tested using the base.
(b) Select any dummy specified in S7 for testing child restraint
systems for use by children of the heights or weights for which the
system is recommended in accordance with S5.5 of Standard No. 213
(Sec. 571.213). The dummy is assembled, clothed and prepared as
specified in S8 and part 572 of this chapter, as appropriate.
(c) The dummy is placed and positioned in the child restraint
system as specified in S9. Attach the child restraint belts used to
restrain the child within the system, if appropriate, as specified in
S9.
(d) Shoulder and pelvic belts that directly restrain the dummy are
adjusted as follows: Tighten the belt system used to restrain the child
within the child restraint system to any tension of not less than 9
Newtons and not more than 18 Newtons on the webbing at the top of each
dummy shoulder and the pelvic region. Tighten the belt systems used to
attach the restraint to the SISA sliding seat to any tension of not
less than 53.5 Newtons and not more than 67 Newtons.
(e) Accelerate the test platform in accordance with S6.1.1(b).
(f) All instrumentation and data reduction is in conformance with
SAE J211/1 (1995) (incorporated by reference, see Sec. 571.5).
S6.2 Buckle release test procedure.
(a) After completion of the testing specified in S6.1 and before
the buckle is unlatched, tie a self-adjusting sling to each wrist and
ankle of the test dummy in the manner illustrated in Figure 4 to
Standard No. 213 (Sec. 571.213), without disturbing the belted dummy
and the child restraint system.
(b) Pull the sling that is tied to the dummy restrained in the
child restraint system and apply the following force: 90 Newtons for a
system tested with a 12-month-old dummy; 200 Newtons for a system
tested with a 3-year-old dummy. For an add-on child restraint, the
force is applied in the manner illustrated in Figure 4 to Standard No.
213 (Sec. 571.213) and by pulling the sling horizontally and parallel
to the SORL of the SISA.
(c) While applying the force specified in S6.2(b), and using the
device shown in Figure 8 of Standard No. 213 (Sec. 571.213) for
pushbutton-release buckles, apply the release force in the manner and
location specified in S6.2.1 of Standard No. 213 (Sec. 571.213), for
that type of buckle. Measure the force required to release the buckle.
S7 Test dummies.
S7.1 Dummy selection. At NHTSA's option, any dummy specified in
S7.1(a) or S7.1(b) may be selected for testing child restraint systems
for use by children of the height or mass for which the system is
recommended in accordance with S5.5 of Standard No. 213 (Sec.
571.213). A child restraint that meets the criteria in two or more of
the following paragraphs may be tested with any of the test dummies
specified in those paragraphs.
(a) A child restraint that is recommended by its manufacturer in
accordance with S5.5 of Standard No. 213 (Sec. 571.213) for use either
by children in a specified mass range that includes any children having
a mass greater than 5 kilograms but not greater than 13.6 kilograms, or
by children in a specified height range that includes any children
whose height is greater than 650 millimeters but not greater than 870
millimeters, is tested with a CRABI 12-month-old test dummy conforming
to 49 CFR part 572 subpart R.
(b) A child restraint that is recommended by its manufacturer in
accordance with S5.5 of Standard No. 213 (Sec. 571.213) for use either
by children in a specified mass range that includes any children having
a mass greater than 13.6 kilograms but not greater than 18 kilograms,
or by children in a specified height range that includes any children
whose height is greater than 870 millimeters but not greater than 1100
millimeters, is tested with a 3-year-old test dummy (Q3s) conforming to
49 CFR part 572 subpart W.
S8 Dummy clothing and preparation.
S8.1 Type of clothing.
(a) 12-month-old dummy (CRABI) (49 CFR part 572, subpart R). When
used in testing under this standard, the dummy specified in 49 CFR part
572, subpart R, is clothed in a cotton-polyester based tight fitting
sweat shirt with long sleeves and ankle long pants whose combined
weight is not more than 0.25 kilograms.
(b) 3-year-old side impact dummy (Q3s) (49 CFR part 572, subpart
W). When used in testing under this standard, the dummy specified in 49
CFR part 572, subpart W, is clothed as specified in that subpart,
except without shoes.
S8.2 Preparing dummies. When using the Q3s dummy, install the IR-
TRACC on the test impact side according to 49 CFR part 572, subpart W.
Before being used in testing under this standard, test dummies must be
conditioned at any ambient temperature from 20.6[deg] to 22.2 [deg]C
and at any relative humidity from 10 percent to 70 percent, for at
least 4 hours.
S9 Positioning the dummy and attaching the belts used to restrain
the child within the child restraint system and/or to attach the system
to the SISA sliding seat.
S9.1 12-month-old dummy (CRABI) (49 CFR part 572, subpart R).
Position the test dummy according to the instructions for child
positioning that the manufacturer provided with the child restraint
system under S5.6.1 or S5.6.2 of Standard No. 213 (Sec. 571.213),
while conforming to the following:
(a) When testing rear-facing child restraint systems, place the 12-
month-old dummy in the child restraint system so that the back of the
dummy torso contacts the back support surface of the
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system. Attach all appropriate child restraint belts used to restrain
the child within the child restraint system and tighten them as
specified in S6.1.2 of this standard. Attach all appropriate belts used
to attach the child restraint system to the SISA sliding seat and
tighten them as specified in S6.1.2.
(b) When testing forward-facing child restraint systems, extend the
dummy's arms vertically upwards and then rotate each arm downward
toward the dummy's lower body until the arm contacts a surface of the
child restraint system or the SISA. Ensure that no arm is restrained
from movement in other than the downward direction, by any part of the
system or the belts used to anchor the system to the SISA sliding seat.
(c) When testing forward-facing child restraint systems, extend the
arms of the 12-month-old test dummy as far as possible in the upward
vertical direction. Extend the legs of the test dummy as far as
possible in the forward horizontal direction, with the dummy feet
perpendicular to the centerline of the lower legs. Using a flat square
surface with an area of 2,580 square mm, apply a force of 178 Newtons,
perpendicular to the plane of the back of the standard seat assembly,
first against the dummy crotch and then at the dummy thorax in the
midsagittal plane of the dummy. Attach all appropriate child restraint
belts used to restrain the child within the child restraint system and
tighten them as specified in S6.1.2(d). Attach all appropriate belts
used to attach the child restraint system (per S5.1.6) to the SISA
sliding seat and tighten them as specified in S6.1.2.
(d) After the steps specified in paragraph (c), rotate each dummy
limb downwards in the plane parallel to the dummy's midsagittal plane
until the limb contacts a surface of the child restraint system or the
standard seat assembly. Position the limbs, if necessary, so that limb
placement does not inhibit torso or head movement in tests conducted
under S6.
S9.2 3-year-old side impact dummy (Q3s) (49 CFR part 572, subpart
W) in forward-facing child restraints. Position the test dummy
according to the instructions for child positioning that the restraint
manufacturer provided with the child restraint system in accordance
with S5.6.1 or S5.6.2 of Standard No. 213 (Sec. 571.213), while
conforming to the following:
(a) Holding the test dummy torso upright until it contacts the
child restraint system's design seating surface, place the test dummy
in the seated position within the child restraint system with the
midsagittal plane of the test dummy head coincident with the center of
the child restraint system.
(b) Extend the arms of the test dummy as far as possible in the
upward vertical direction. Extend the legs of the dummy as far as
possible in the forward horizontal direction, with the dummy feet
perpendicular to the center line of the lower legs.
(c) For a child restraint system with a fixed or movable surface,
position each movable surface in accordance with the instructions that
the manufacturer provided under S5.6.1 or S5.6.2 of Standard No. 213
(Sec. 571.213). For forward-facing restraints, attach all appropriate
child restraint belts used to restrain the child within the child
restraint system and tighten them as specified in S6.1.2(d). Attach all
appropriate belts or lower anchorage attachments used to attach the
child restraint system to the SISA or to restrain the child and tighten
them as specified in S6.1.2. For belt-positioning seats, attach all
appropriate vehicle belts used to restrain the child within the child
restraint system and tighten them as specified in S6.1.2(d).
(d) After the steps specified in paragraph (c) of this section,
rotate each of the dummy's legs downwards in the plane parallel to the
dummy's midsagittal plane until the limb contacts a surface of the
child restraint or the SISA. Rotate each of the dummy's arms downwards
in the plane parallel to the dummy's midsagittal plane until the arm is
engaged on the detent that positions the arm at a 25 degree angle with
respect to the thorax.
S9.3 3-year-old side impact dummy (Q3s) (49 CFR part 572, subpart
W) in rear-facing child restraints. Position the test dummy according
to the instructions for child positioning that the restraint
manufacturer provided with the child restraint system in accordance
with S5.6.1 or S5.6.2 of Standard No. 213 (Sec. 571.213), while
conforming to the following:
(a) Extend the arms of the test dummy as far as possible in the
upward vertical direction. Extend the legs of the dummy as far as
possible in the forward horizontal direction, with the dummy feet
perpendicular to the center line of the lower legs.
(b) Place the Q3s dummy in the child restraint system so that the
back of the dummy torso contacts the back support surface of the
system. Place the test dummy in the child restraint system with the
midsagittal plane of the test dummy head coincident with the center of
the child restraint system. Rotate each of the dummy's legs downwards
in the plane parallel to the dummy's midsagittal plane until the leg or
feet of the dummy contacts the seat back of the SISA or a surface of
the child restraint system.
(c) For a child restraint system with a fixed or movable surface,
position each movable surface in accordance with the instructions that
the manufacturer provided under S5.6.1 or S5.6.2 of Standard No. 213
(Sec. 571.213). Attach all appropriate child restraint belts used to
restrain a child within the child restraint system and tighten them as
specified in S6.1.2(d). Attach all appropriate belts or lower anchorage
attachments used to attach the child restraint system to the SISA and
tighten them as specified in S6.1.2.
(d) After the steps specified in paragraph (c) of this section,
rotate each dummy arm downwards in the plane parallel to the dummy's
midsagittal plane until the limb is positioned at a 25-degree angle
with respect to the thorax.
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Issued under authority delegated in 49 CFR 1.95 and 501.5.
Steven S. Cliff,
Administrator.
[FR Doc. 2022-13658 Filed 6-29-22; 8:45 am]
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