[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 
<a href="/cdn-cgi/l/email-protection#fc9294888f9dd28b999e919d8f88998ebc989388d29b938a"><span class="__cf_email__" data-cfemail="254b4d5156440b52404748445651405765414a510b424a53">[email protected]</span></a>.
    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 <a href="/cdn-cgi/l/email-protection#8ccffee5fff8e5e2eda2c9efe4e9e1e9e2e8e5edcce8e3f8a2ebe3fa"><span class="__cf_email__" data-cfemail="307342594344595e511e755358555d555e54595170545f441e575f46">[email protected]</span></a>. For legal issues, 
Deirdre Fujita or Hannah Fish, Office of the Chief Counsel, telephone 
202-366-2992, email <a href="/cdn-cgi/l/email-protection#a7e3c2c289e1d2cdced3c6e7c3c8d389c0c8d1"><span class="__cf_email__" data-cfemail="cf8baaaae189baa5a6bbae8faba0bbe1a8a0b9">[email protected]</span></a> or <a href="/cdn-cgi/l/email-protection#7139101f1f10195f3718021931151e055f161e07"><span class="__cf_email__" data-cfemail="9ed6fff0f0fff6b0d8f7edf6defaf1eab0f9f1e8">[email protected]</span></a>. 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 (T<INF>0</INF>)--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.

[[Page 39236]]

    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

[[Page 39237]]

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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \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.
    <bullet> 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.
---------------------------------------------------------------------------

    <bullet> The tolerance in the relative velocity (V<INF>0</INF>) 
between the sliding seat and the door assembly at time of initial 
contact (T<INF>0</INF>) is reduced in the final rule from the proposed 
31.3 <plus-minus> 0.8 km/h to 31.3 <plus-minus> 0.64 km/h to improve 
repeatability and reproducibility of the test.
    <bullet> The NPRM proposed that the test platform velocity during 
the time of interaction of the door with the CRS would be no greater 
than V<INF>0</INF> and not less than V<INF>0</INF>-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 = T<INF>0</INF>. This change provides 
more flexibility to different test facilities to meet the test 
specifications while maintaining satisfactory test repeatability and 
reproducibility.
    <bullet> 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.
---------------------------------------------------------------------------

    <bullet> 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.
    <bullet> 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.
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    \45\ Subtitle E is entitled ``Child Safety Standards.''
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    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.
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    \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.
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    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.''
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    \48\ Docket No. NHTSA-2009-0108-0032.
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    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.
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    \49\ There are still no child test dummies that are suitable for 
use in a side impact FMVSS other than the Q3s.
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    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.
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    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).
---------------------------------------------------------------------------

    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'').
---------------------------------------------------------------------------

    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.''
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \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.)
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \71\ 85 FR 69388, supra.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \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).
---------------------------------------------------------------------------

    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\
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    \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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    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.''
---------------------------------------------------------------------------

    \93\ NHTSA proposed a 500 mm (19.6 in) beltline height for the 
SISA. See, 79 FR at 4587-4588.
---------------------------------------------------------------------------

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\
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

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).
---------------------------------------------------------------------------

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:
    <bullet> A single seating position representing a rear outboard 
seating position.
    <bullet> 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.
    <bullet> 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.
    <bullet> 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).
---------------------------------------------------------------------------

    <bullet> 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.
    <bullet> 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 <plus-minus> 0.5 inches (101.6 <plus-minus> 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 
(<plus-minus>0.5 inches (<plus-minus>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 <plus-minus> 0.25 inches (101.6 <plus-minus> 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 <plus-minus> 21.......  58........................              60
    Lateral.............................  137 <plus-minus> 29.......  140.......................             141
    Vertical (-) Below point A..........  -12 <plus-minus> 24.......  -38.......................             -39
Tether Anchors (Seat Back Position):      ..........................
    Aft.................................  280 <plus-minus> 88.......  330.......................             324
    Lateral.............................  0 <plus-minus> 44.........  0.........................               5
    Vertical (-) Below point A..........  140 <plus-minus> 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.
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    \167\ Figures illustrating the Type 2 seat belt testing showing 
no interference with the door are docketed with this final rule.
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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:
    <bullet> A trapezoidal sliding seat acceleration profile 
(representing the struck vehicle acceleration) based on an analysis of 
ten small vehicle FMVSS No. 214 tests.
    <bullet> 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).
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    <bullet> 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.
---------------------------------------------------------------------------

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.
---------------------------------------------------------------------------

    \172\ Sullivan et al. (2009).
---------------------------------------------------------------------------

    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.
BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TR30JN22.009

BILLING CODE 4910-59-C

[[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.
---------------------------------------------------------------------------

    \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 T<INF>0</INF> (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 T<INF>0</INF>. Next, MGA suggested the agency 
change the slope of the lower boundary of the corridor from time 
T<INF>0</INF> to time 15 msec after T<INF>0</INF> 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 T<INF>0</INF> 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 T<INF>0</INF>. 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 T<INF>0</INF>.\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 T<INF>0</INF>.
---------------------------------------------------------------------------

    \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 T<INF>0</INF> and 15 msec after 
T<INF>0</INF>, 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 T<INF>0</INF> 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 
(V<INF>0</INF>) of 31.3 <plus-minus> 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 = T<INF>0</INF>); and 
(2) ensure the sliding seat has a change in velocity of 31.3 <plus-
minus> 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 
(V<INF>0</INF>) and greater than or equal to V<INF>0</INF>-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(T<INF>0</INF>)-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 T<INF>0</INF> 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.
---------------------------------------------------------------------------

    \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 T<INF>0,</INF> 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 
T<INF>0</INF>.
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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.
---------------------------------------------------------------------------

    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 T<INF>0</INF> (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 (T<INF>0</INF>) 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 (V<INF>0</INF>) of 31.3 <plus-minus> 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 (T<INF>0</INF>).'' 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).
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \183\ Supra, see Docket No. NHTSA-2014-0012.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    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.
BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TR30JN22.012

    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

BILLING CODE 4910-59-C
5. Relative Velocity at Impact Time (T<INF>0</INF>)--Tolerance
---------------------------------------------------------------------------

    \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 (T<INF>0</INF>) relative velocity 
(V<INF>0</INF>) of 31.3 <plus-minus> 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 T<INF>0</INF> on performance 
measures. NHTSA intended to conduct three tests of a CRS model by 
varying the relative velocity at time T<INF>0</INF> 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 <plus-minus> 0.64 km/h (instead of 31.3 <plus-minus> 
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 T<INF>0</INF> 
(T<INF>0</INF> 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 T<INF>0</INF> and 185 mm (7.3 in) at 
T<INF>0</INF>+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 T<INF>0</INF>-65 and T<INF>0,</INF> there was no 
head displacement, while measurement from T<INF>0</INF> to 
T<INF>0</INF>+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 T<INF>0</INF> 
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 
T<INF>0</INF> (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 
(T<INF>0</INF>) was 48.9 mm at VRTC and 62.1 mm at Kettering. The 
maximum range of head forward displacement in the X-direction at 
T<INF>0</INF> 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 T<INF>0</INF> 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 T<INF>0</INF> 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.
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[[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:
    <bullet> 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;
    <bullet> Belt-positioning booster seats would be tested with Type 2 
(lap and shoulder) belts; and,
    <bullet> 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.
    <bullet> The Q3s dummy would be positioned in the child restraint 
according to the manufacturer's positioning procedures.
    <bullet> 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.
    <bullet> 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 T<INF>0</INF>. 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 (T<INF>0</INF>) (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 <plus-minus>2 mm to <plus-minus>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 
(T<INF>0</INF>) to 38 <plus-minus> 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\
---------------------------------------------------------------------------

    \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\
---------------------------------------------------------------------------

    \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:
    <bullet> 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.
    <bullet> 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.
    <bullet> 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

    <bullet> 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.
    <bullet> 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.
    <bullet> 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.
    <bullet> 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.
    <bullet> 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.
    <bullet> 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.
    <bullet> 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.
    <bullet> 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.<SUP>233 234</SUP> 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\
---------------------------------------------------------------------------

    \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\
---------------------------------------------------------------------------

    \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).
---------------------------------------------------------------------------

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.
---------------------------------------------------------------------------

    \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.<SUP>250 251</SUP> 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.
---------------------------------------------------------------------------

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\
---------------------------------------------------------------------------

    \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\
---------------------------------------------------------------------------

    \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\
---------------------------------------------------------------------------

    \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\
---------------------------------------------------------------------------

    \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:
    <bullet> Have we organized the material to suit the public's needs?
    <bullet> Are the requirements in the rule clearly stated?
    <bullet> Does the rule contain technical language or jargon that 
isn't clear?
    <bullet> Would a different format (grouping and order of sections, 
use of headings, paragraphing) make the rule easier to understand?
    <bullet> Would more (but shorter) sections be better?
    <bullet> Could we improve clarity by adding tables, lists, or 
diagrams?
    <bullet> 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: <a href="/cdn-cgi/l/email-protection#2f495d0146415c5f4a4c5b4640416f414e5d4e01484059"><span class="__cf_email__" data-cfemail="f99f8bd790978a899c9a8d909697b997988b98d79e968f">[email protected]</span></a>, 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, a<INF>r</INF>, 
expressed as a multiple of g (the acceleration of gravity), calculated 
using the expression:

[[Page 39311]]

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    (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 <plus-minus> 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 = T<INF>0</INF>). The front face of the armrest 
on the door is 38 <plus-minus> 6 millimeters from the edge of the seat 
towards the SORL at time = T<INF>0</INF>. 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 = T<INF>0</INF>.
    (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 <plus-minus> 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

[[Page 39313]]

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.
BILLING CODE 4910-59-P

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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]
BILLING CODE 4910-59-C


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