[Federal Register Volume 79, Number 18 (Tuesday, January 28, 2014)]
[Proposed Rules]
[Pages 4569-4608]
[FR Doc No: 2014-01568]

Vol. 79

Tuesday,

No. 18

January 28, 2014

Part III

Department of Transportation

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National Highway Traffic Safety Administration

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49 CFR Part 571

Federal Motor Vehicle Safety Standards; Child Restraint Systems, Child
Restraint Systems--Side Impact Protection, Incorporation by Reference;
Proposed Rule

Federal Register / Vol. 79 , No. 18 / Tuesday, January 28, 2014 /
Proposed Rules

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. NHTSA-2014-0012]
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: Notice of proposed rulemaking (NPRM).

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SUMMARY: This NPRM proposes to amend Federal Motor Vehicle Safety
Standard (FMVSS) No. 213, ``Child restraint systems,'' to adopt side
impact performance requirements for all child restraint systems
designed to seat children in a weight range that includes weights up to
18 kilograms (kg) (40 pounds (lb)). NHTSA is issuing this NPRM to
ensure that child restraints provide a minimum level of protection in
side impacts by effectively restraining the child, preventing harmful
head contact with an intruding vehicle door or child restraint
structure, and by attenuating crash forces to the child's head and
chest.
    This NPRM is also issued toward fulfillment of a statutory mandate
set forth in the ``Moving Ahead for Progress in the 21st Century Act''
(July 6, 2012), directing the Secretary of Transportation to issue a
final rule amending FMVSS No. 213 to improve the protection of children
seated in child restraint systems during side impacts.

DATES: Comments must be received on or before April 28, 2014.
    Proposed compliance date: We propose that the compliance date for
the amendments in this rulemaking action would be three years following
the date of publication of the final rule in the Federal Register.
Optional early compliance would be permitted.

ADDRESSES: You may submit comments to the docket number identified in
the heading of this document by any of the following methods:
     Federal eRulemaking Portal: go to http://www.regulations.gov. Follow the online instructions for submitting
comments.
     Mail: Docket Management Facility, M-30, U.S. Department of
Transportation, West Building, Ground Floor, Rm. W12-140, 1200 New
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery or Courier: West Building Ground Floor, Room
W12-140, 1200 New Jersey Avenue SE., between 9 a.m. and 5 p.m. Eastern
Time, Monday through Friday, except Federal holidays.
     Fax:<PHONE_NUMBER>.
    Regardless of how you submit your comments, please mention the
docket number of this document.
    You may also call the Docket at<PHONE_NUMBER>.
    Instructions: For detailed instructions on submitting comments and
additional information on the rulemaking process, see the Public
Participation heading of the Supplementary Information section of this
document. Note that all comments received will be posted without change
to http://www.regulations.gov, including any personal information
provided.
    Privacy Act: Please see the Privacy Act heading under Rulemaking
Analyses and Notices.

FOR FURTHER INFORMATION CONTACT: For technical issues, you may call
Cristina Echemendia, Office of Crashworthiness Standards, (Telephone:
202-366-6345) (Fax:<PHONE_NUMBER>). For legal issues, you may call
Deirdre Fujita, Office of Chief Counsel (Telephone:<PHONE_NUMBER>) (Fax:
202-366-3820). Mailing address: 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. Statutory Mandate
III. The Existing Standard
IV. Summary of Proposed Amendments
V. Guiding Principles
VI. Potentially Affected Child Restraints
VII. Real World Analysis
VIII. Past NHTSA Efforts
IX. Side Impact Program Developments
    a. Side Impact Environment for Children
    b. Injury Mechanisms in Side Impact
    c. Global Dynamic Side Impact Tests
    d. Side Impact Test Dummy
X. Developing NHTSA's Side Impact Test
    a. Assessment of Existing Global Efforts
    b. Takata Test Procedure
XI. The Proposed Test Procedure
    a. Sled Kinematic Parameters
    1. Sliding Seat Acceleration Profile (Representing the Struck
Vehicle)
    2. Door Velocity
    3. Sled Buck Angle (Replicating Longitudinal Component of the
Direction of Force)
    b. Rear Seat Environment Parameters
    1. Rear Seat Cushion Stiffness
    2. Rear Seat Door Stiffness
    3. Rear Seat Environment Geometry
    c. Dynamic Validation of the Sled Test
XII. Proposed Dynamic Performance
    a. Q3s Dummy
    b. CRABI Dummy
    c. Energy Absorption and Distribution
XIII. Fleet Testing
    a. Q3s Dummy
    b. CRABI Dummy
XIV. Countermeasure Assessment
XV. Petition Regarding Deceleration Sled System
XVI. Costs and Benefits
XVII. Effective Date
XVIII. Regulatory Notices and Analyses
XIX. Public Participation

    This NPRM proposes to amend FMVSS No. 213, ``Child restraint
systems,'' to adopt side impact performance requirements for all child
restraint systems designed to seat children in a weight range that
includes weights up to 18 kg (40 lb). Frontal and side crashes account
for most child occupant fatalities. Standard No. 213 currently requires
child restraints to meet a dynamic test simulating a 48.3 kilometers
per hour (30 miles per hour) frontal impact. Today's proposal would
require an additional test in which such child restraints must protect
the child occupant in a dynamic test simulating a full-scale vehicle-
to-vehicle side impact.
    Child restraints would be tested with a newly-developed
instrumented side impact test dummy representing a 3-year-old child,
called the Q3s dummy, and with a well-established 12-month-old child
test dummy (the Child Restraint Air Bag Interaction (CRABI) dummy).
NHTSA is issuing this NPRM to ensure that child restraints provide a
minimum level of protection in side impacts by effectively restraining
the child, preventing harmful head contact with an intruding vehicle
door or child restraint structure, and by attenuating crash forces to
the child's head and chest.
    This NPRM is also issued toward fulfillment of a statutory mandate
set forth in the ``Moving Ahead for Progress in the 21st Century Act''
(July 6, 2012), directing the Secretary of Transportation to issue a
final rule amending FMVSS No. 213 to improve the protection of children
seated in child restraint systems during side impacts.

I. Executive Summary

    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. 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, crushable metal 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 vehicle-to-vehicle side impact crash, the striking vehicle
first interacts with the door structure of the struck vehicle and
commences crushing the door and intruding laterally into the vehicle
compartment. Second, the striking vehicle engages the sill of the
struck vehicle and begins to push the struck vehicle away. At this
time, the occupant sitting in the vehicle experiences the struck
vehicle seat moving away from the impacting vehicle while the door
intrudes towards him or her. Next, the occupant interacts with the
intruding door, after which the occupant is accelerated away from the
door until the occupant reaches the velocity of the struck and striking
vehicle.
    Passenger vehicles provide protection in vehicle-to-vehicle crashes
by meeting FMVSS No. 214, ``Side impact protection.'' FMVSS No. 214
requires passenger vehicles to provide side impact protection in
several different side 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 a moving deformable barrier (MDB)
simulating an impacting vehicle.\2\ 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).\3\ The struck vehicle must limit the potential for
injuries to an occupant's head, thorax, and pelvis, as measured by test
dummies seated in the front outboard seat and rear outboard seat on the
struck side of the vehicle (``near side'' positions).
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    \2\ FMVSS No. 214 also specifies a static laboratory test that
has greatly improved side door strength and protection against side
impacts with fixed objects. The static test has resulted in
manufacturers reinforcing side doors with a horizontal beam. In
addition, FMVSS No. 214 specifies a full-scale side crash test of a
vehicle into a pole, which has resulted in the installation of side
air bags to protect against head and chest injuries.
    \3\ 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 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.
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    Today's NPRM proposes a side impact test that simulates the two-
vehicle side crash replicated by the FMVSS No. 214 MDB test of a small
passenger car. Today's proposal would require all child restraint
systems (CRSs) designed to seat children in a weight range that
includes weights up to18 kg (40 lb) to meet specific performance
criteria in a dynamic sled test that simulates the MDB test (striking
vehicle traveling at 48.3 km/h (30 mph) impacting the struck vehicle
traveling at 24 km/h (15 mph)). Approximately 92 percent of side
crashes involving restrained children are of equivalent or lower crash
severity than the FMVSS No. 214 MDB crash test of a small passenger
car.\4\
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    \4\ 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 YO in all
restraint environments including seat belts and CRS. Details of the
analysis are provided in the technical report in the docket for this
NPRM.
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    The proposed sled test is the first of its kind in the world for
testing child restraints in a sled system that simulates the vehicle
acceleration and intruding door of a small passenger car in a side
impact (a vehicle-to-vehicle intersection crash). We do not have
sufficient data to determine what share of covered crashes involve an
intruding door, however door intrusion is a causative factor for
moderate and serious injury to children in side impacts. Child
restraints would be tested in the side impact sled test with the Q3s
instrumented side impact test dummy representing the size and weight of
a 3-year-old (3 YO) child, and with the CRABI dummy representing a 12-
month-old (12 MO) infant. NHTSA has previously published an NPRM
proposing to amend our regulation for anthropomorphic test devices, 49
CFR Part 572, to add specifications for the Q3s (78 FR 69944; November
21, 2013). The CRABI dummy's specifications are incorporated into 49
CFR Part 572, Subpart R.
    NHTSA is issuing this NPRM to ensure that subject child restraints
provide a minimum level of protection in side impacts. The CRSs would
have to effectively restrain the child, prevent harmful head contact
with an intruding vehicle door or child restraint structure, and
attenuate crash forces to the child's chest. Injury criteria (expressed
in terms of a head injury criterion (HIC) and chest deflection) are
proposed for the Q3s. These criteria allow a quantitative evaluation of
the effectiveness of the CRS to prevent or attenuate head and chest
impact with the intruding door. The 12 MO CRABI would be used to
measure the containment capability of the CRS (the ability to prevent
the dummy's head from making contact with the intruding door of the
sled assembly). In addition, CRSs would be required to meet other
structural integrity requirements in the sled test that ensure a sound
level of performance in side impacts.
    We estimate that a final rule resulting from this proposal would
reduce 5.2 fatalities and 64 non-fatal injuries (MAIS \5\ 1-5) annually
(see Table 1 below).\6\ The equivalent lives and the monetized benefits
were estimated in accordance with guidance issued February 28, 2013 by
the Office of the Secretary \7\ regarding the treatment of value of a
statistical life in regulatory analyses. A final rule resulting from
this proposal is estimated to save 18.26 equivalent lives annually. The
monetized annual benefits of the proposed rule at 3 and 7 percent
discount rates are $182.6 million and $165.7 million, respectively
(Table 2). We estimate that the annual cost of this proposed rule would
be approximately $3.7 million. The countermeasures may include larger
wings and padding with energy absorption characteristics that cost, on
average, approximately $0.50 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
$162.0 million (7 percent discount rate) to $178.9 million (3 percent
discount rate) as shown in Table 4. Because the proposed rule is cost
beneficial just by comparing costs to monetized economic benefits, and
there is a net benefit, we are not providing a net cost per equivalent
life saved since no value would be provided by such an estimate.
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    \5\ 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.
    \6\ NHTSA has developed a Preliminary Regulatory Impact Analysis
(PRIA) that discusses issues relating to the potential costs,
benefits, and other impacts of this regulatory action. The PRIA is
available in the docket for this NPRM 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.
    \7\ http://www.dot.gov/sites/dot.dev/files/docs/VSL%20Guidance%202013.pdf.

                       Table 1--Estimated Benefits
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Fatalities.................................................          5.2
Non-fatal injuries (MAIS 1 to 5)...........................           64
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                                      Table 2 Estimated Monetized Benefits
                                          [In millions of 2010 dollars]
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                                                                                Value of
                                                                     Economic       statistical   Total benefits
                                                                     benefits          life
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3 Percent Discount Rate.........................................           $16.0          $166.6          $182.6
7 Percent Discount Rate.........................................            14.4           151.3           165.7
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                Table 3--Estimated Costs (2010 Economics)
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Average cost per CRS designed for children  $0.50
 in a weight range that includes weights
 up to 40 lb.
                                           -----------------------------
    Total annual cost.....................  3.7 million
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                                     Table 4--Annualized Costs and Benefits
                                          [In millions of 2010 dollars]
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                                                                    Annualized      Annualized
                                                                       costs         benefits      Net benefits
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3% Discount Rate................................................            $3.7          $182.6          $178.9
7% Discount Rate................................................             3.7           165.7           162.0
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    Accident data indicate that CRSs designed for children in a weight
range that includes weights up to 18 kg (40 lb) are generally already
remarkably effective in reducing the risk of death and serious injury
in side impacts. We have observed in recent years that increasing
numbers of these CRSs appear to have more side structure coverage (CRS
side ``wings'') and side padding than before.\8\ 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, we consider the
side wing coverage and increased padding to be overall positive
developments. Yet, because FMVSS No. 213 currently does not have a side
impact test, a quantifiable assessment of the protective qualities of
the features was heretofore not possible. Today's NPRM would establish
performance requirements that ensure that the wings, padding, padding-
like features, or other countermeasures employed in recent years
reportedly to provide protection in side impacts will in fact achieve a
minimum level of performance that will reduce the risk of injury or
fatality in side impacts. For CRS designs that have not yet
incorporated side impact protection features, today's NPRM is the first
step toward ensuring that they will.
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    \8\ SafetyBeltSafe U.S.A. http://www.carseat.org/Pictorial/InfantPict,1-11.pdf and http://www.carseat.org/Pictorial/3-Five-%20Point-np.pdf. Last accessed January 24, 2013.
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II. Statutory Mandate

    On July 6, 2012, President Obama signed the ``Moving Ahead for
Progress in the 21st Century Act'' (MAP-21), P.L. 112-141. Subtitle E
of MAP-21, entitled ``Child Safety Standards,'' includes section
31501(a) which states that, not later than 2 years after the date of
enactment of the Act, the Secretary shall issue a final rule amending
Federal Motor Vehicle Safety Standard Number 213 to improve the
protection of children seated in child restraint systems during side
impact crashes.\9\
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    \9\ Subtitle E also includes provisions for commencing a
rulemaking to amend the standard seat assembly specifications in
FMVSS No. 213 to better simulate a single representative motor
vehicle rear seat (section 31501(b)), and initiating a rulemaking to
amend FMVSS No. 225, ``Child restraint anchorage systems,'' to
improve the ease of use of lower anchorages and tethers (section
31502(a)). The agency anticipates dealing with these provisions in
future rulemakings.
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    We interpret this provision of MAP-21 as providing us a fair amount
of discretion. NHTSA informed Congress in 2004 that enhanced side
impact protection for children in child restraints was a priority for
NHTSA.\10\ The agency informed Congress that it will continue efforts
to obtain detailed side crash data to identify specific injury
mechanisms involving children and will work on countermeasure
development using test dummies, including the European Q3 dummy then
available, for improved side impact protection. Our current NHTSA
Vehicle Safety and Fuel Economy Rulemaking and Research Priority Plan
2011-2013, March 2011,\11\ announced our intention to issue an NPRM in
2012 on child restraint side impact protection. The plan shows that we
were 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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    \10\ NHTSA Report to Congress, ``Child Restraint Systems,
Transportation Recall Enhancement,
    Accountability, and Documentation Act,'' February 2004.
www.nhtsa.gov/nhtsa/announce/NHTSAReports/TREAD.pdf.
    \11\ Docket No. NHTSA-2009-0108-0032.
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    We believe that MAP-21's short deadline for issuance of a final
rule indicates that Congress intended for NHTSA to use the existing
state of knowledge gained from our research efforts to initiate and
complete the regulation as the agency had planned. There are no child
test dummies other than the Q3s available at this time that have been
proven sufficiently durable

and reliable for use in the proposed FMVSS No. 213 side impact testing.
The level and amount of effort needed to further develop and validate a
different test procedure, or new child side impact test dummies, far
exceeds what could be accomplished within the time constraints of the
Act.
    Further, MAP-21 requires a final rule amending FMVSS No. 213, which
means that the rulemaking must be conducted in accordance with the
National Traffic and Motor Vehicle Safety Act (49 U.S.C. 30101 et seq.)
(``Vehicle Safety Act''). Under the Vehicle Safety Act, the Secretary
of Transportation 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.\12\ ``Motor vehicle safety''
is defined in the Vehicle 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.'' \13\ When prescribing such
standards, the Secretary must consider all relevant, available motor
vehicle safety information, and consider whether a standard is
reasonable, practicable, and appropriate for the types of motor
vehicles or motor vehicle equipment for which it is prescribed.\14\ The
Secretary must also consider the extent to which the standard will
further the statutory purpose of reducing traffic accidents and
associated deaths.\15\
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    \12\ 49 U.S.C. 30111(a).
    \13\ 49 U.S.C. 30102(a)(8).
    \14\ 49 U.S.C. 30111(b).
    \15\ Id.
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    We have developed a regulation 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 Vehicle Safety Act. We believe that the proposed regulation meets
the need for safety, is stated in objective terms, and is reasonable,
practicable, and appropriate. While the language of section 31501(a) of
MAP-21 is broad enough to encompass a large universe of child restraint
systems, 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 kg (40 lb). For one, 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
proposed today. 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 kg
(40 lb). In addition, 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. These reasons are further discussed in a section below, and
are presented for public comment.

III. The Existing Standard

    CRSs 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).\16\ Child restraint effectiveness for children between the ages
1 to 4 YO is 54 percent in passenger cars and 59 percent in light
trucks. Id.
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    \16\ ``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, http://www-nrd.nhtsa.dot.gov/Pubs/96855.pdf,
last accessed on May 2, 2012.
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    The most significant dynamic performance requirements of FMVSS No.
213 relevant to this NPRM are briefly described below.\17\
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    \17\ FMVSS No. 213 also has labeling and owner's manual
requirements for proper use of the CRS, including requirements that
safety warnings be prominently displayed on the CRS. The standard
also includes requirements for the flammability resistance of the
CRS. The standard also establishes an owner-registration program so
that purchasers can register with the manufacturer and be directly
notified in the event of a safety recall.
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    l. The crash performance of a CRS is evaluated in a frontal dynamic
test involving a 48.3 km/h (30 mph) velocity change, which is
representative of a severe crash. CRSs are tested while attached to a
standardized seat assembly representative of a passenger vehicle seat.
CRSs other than booster seats must meet minimum performance
requirements when anchored to the standard seat assembly with a lap
belt only, or with the lower anchorages of the ``LATCH'' \18\ system.
The CRSs must meet more stringent head excursion requirements in
another test, one in which a top tether, if provided, is permitted to
be attached. Belt-positioning (booster) seats are tested on the
standard seat assembly using a lap and shoulder belt.\19\
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    \18\ LATCH refers to Lower Anchors and Tethers for Children, an
acronym developed by manufacturers and retailers to refer to the
child restraint anchorage system required by FMVSS No. 225 for
installation in motor vehicles. LATCH 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 LATCH system.
    \19\ Built-in CRSs are evaluated by crash testing the vehicle
into which the CRSs are built, or by simulating a crash with the
built-in seat dynamically tested with parts of the vehicle
surrounding it.
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    2. CRSs are dynamically tested with anthropomorphic test devices
(ATDs) (child test dummies) representative of the children for whom the
CRS is recommended. FMVSS No. 213 specifies the use of ATDs
representing a newborn, a 12 MO infant, a 3 YO, a 6 YO, a weighted 6
YO, and a 10 YO.\20\ Except for the newborn and weighted 6 YO ATDs, the
test dummies are equipped with instrumentation measuring crash forces
imposed on the ATD. The mass, size, and kinematics of the ATDs are
designed to replicate those of a human child.
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    \20\ NHTSA will use the 10 YO child dummy in compliance testing
to test CRSs manufactured on or after February 27, 2014.
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    3. To protect the child, FMVSS No. 213 requires CRSs to limit the
amount of force that can be exerted on the head and chest of the ATD
during the dynamic test. FMVSS No. 213 also requires CRSs to meet head
excursion limits to reduce the possibility of head injury from contact
with vehicle interior surfaces and ejection, and limits knee excursion.
    4. FMVSS No. 213 requires CRSs to maintain system integrity (i.e.,
not fracture or separate in such a way as to harm a child). The
standard also specifies requirements for the size and shape of
contactable surfaces of the CRS to ensure that surfaces that can harm
on impact are absent, and specifies requirements for the performance of
belts and buckles to make sure that, among other things, a buckle can
be swiftly unlatched after a crash by an adult for expeditious egress
from the crash site but cannot be easily unbuckled by an unsupervised
child.

IV. Summary of Proposed Amendments

    This NPRM proposes to amend FMVSS No. 213 to adopt side impact
performance requirements for CRSs designed to seat children in a weight
range that includes weights up to 18 kg (40 lb). The side impact test
requirements would be specified in a new standard, FMVSS No. ``213a.''
FMVSS No. 213 would be amended to include a requirement that the CRSs
covered by this NPRM must meet the new FMVSS No. 213a in addition to
the requirements established in FMVSS No. 213.\21\
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    \21\ A final rule could incorporate the proposed requirements
into FMVSS No. 213, rather than in a separate FMVSS No. 213a. This
NPRM shows the proposed requirements separately in FMVSS No. 213a
for plain language purposes and the reader's convenience.
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    The most significant amendments proposed by this NPRM are described
below.
    1. A dynamic (sled) test would be used to evaluate the performance
of the CRS in a side impact. The sled test was developed based on an
acceleration sled system \22\ developed by Takata. The test procedure
simulates the two-vehicle side crash replicated in the MDB test of
FMVSS No. 214 (striking vehicle traveling at 48.3 km/h (30 mph))
impacting the struck vehicle traveling at 24 km/h (15 mph). The
proposed sled test simulates a near-side side impact of a small
passenger car. It simulates the velocity of the striking vehicle, the
struck vehicle, and an intruding door.
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    \22\ 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.
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    2. The test buck consists 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. The sliding ``vehicle'' seat and side door are
representative of today's passenger vehicles. This ``side impact seat
assembly'' (SISA) proposed for the side impact test is specified by
drawings that have been placed in the docket for today's NPRM. The
sliding vehicle 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 ``vehicle'' seat starts to accelerate to a specific
acceleration profile.
    3. Most CRSs would be attached using LATCH to the sliding
``vehicle'' seat of the SISA. CRSs covered by this NPRM that are not
currently required by FMVSS No. 213 to have LATCH attachments (i.e.,
belt-positioning seats) would be tested using a lap and shoulder belt
on the SISA. 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 from the edge of the seat towards
the child restraint system. For forward-facing CRSs with LATCH
attachments, the LATCH lower anchorages and the top tether, if
provided, would be used (assuming the top tether is recommended for use
in motor vehicles by the CRS manufacturer).
    4. CRSs recommended for children with weights that include 10 kg to
18 kg (22 lb to 40 lb) would be tested on the SISA with an ATD
representing a 3 YO child, referred to as the ``Q3s.'' The Q3s is a
side impact version of the 3 YO child Q-series dummy (Q3), a frontal
crash dummy developed in Europe. CRSs recommended to seat children with
weights up to 10 kg (22 lb) would be tested with the 12 MO CRABI dummy
(49 CFR Part 572, Subpart R).
    5. Injury criteria (expressed in terms of HIC15 \23\ and
chest deflection) are proposed for the Q3s. 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. The CRABI would be used to measure the containment
capability (the ability to prevent the ATD's head from contacting the
intruding door of the SISA) of CRSs recommended for children weighing
more than 5 kg (11 lb) and up to 10 kg (22 lb). In addition, CRSs would
be required to meet structural integrity and other requirements
described in item 4 of the previous section.
---------------------------------------------------------------------------

    \23\ Head injury criterion that is based on the integration of
resultant head acceleration over a 15 millisecond duration.
---------------------------------------------------------------------------

V. Guiding Principles

    The following principles guided our decision-making in developing
this NPRM. Several of these principles have guided our past rulemakings
on FMVSS No. 213.
    a. NHTSA estimates that CRSs are already 42 percent effective in
preventing death in side crashes of 0 to 3 YO children.\24\ This
estimated degree of effectiveness is high, and is only 11 percentage
points lower than CRS effectiveness in frontal crashes (53 percent),
notwithstanding that FMVSS No. 213 requires CRSs to meet specific
performance requirements in a frontal impact sled test but has no such
dynamic performance requirements in side impact. We believe that the
effectiveness of CRSs in side impact can be attributed to the CRS
harness containing the child in the seating position, thereby
mitigating harmful contact with interior vehicle components, and to the
CRS structure shielding the child from direct impact and absorbing some
of the crash forces.
---------------------------------------------------------------------------

    \24\ 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 YO children to be 42 percent in side crashes
and 52 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 docket.
---------------------------------------------------------------------------

    b. In making regulatory decisions on possible enhancements to CRS
performance, the agency must bear in mind the consumer acceptance of
cost increases to an already highly-effective item of safety equipment.
Any enhancement that would significantly raise the price of the
restraints could potentially have an adverse effect on the sales of
this voluntarily-purchased 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. Thus, to
maximize the total safety benefits of its efforts on FMVSS No. 213, the
agency 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 twin
problems of misuse and nonuse of child restraints could be exacerbated.
    c. Estimating the net effect on safety of this rulemaking,
consistent with the principles for regulatory decision-making set forth
in Executive Order (E.O.) 12286, ``Regulatory Planning and Review,''
and E.O. 13563, ``Improving Regulation and Regulatory Review,'' was
limited by several factors. One was that 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 test speed or intrusion level may
have undesirable impacts on FMVSS No. 213 regarding practicability,
cost, and possible detrimental effects on safety (i.e., the possible
effects on the use of CRSs, discussed above).

    Another limiting factor was there is no information comparing the
real world performance of ``good'' performing CRSs versus ``poor''
performing CRSs. Without these data, we had to use test data and injury
curves to determine the effectiveness of possible countermeasures
(e.g., large side wings with energy absorbing padding). We are also
limited by the unavailability of child ATDs for side impact testing.
Currently, there is only an ATD representing a 3 YO child that has been
specially developed for side impacts. The 12 MO CRABI dummy is a
frontal impact dummy, and can only be used in a limited capacity to
estimate benefits in this side impact rulemaking.
    d. In developing this NPRM, we sought to build on the levels of
side impact protection provided by FMVSS No. 214. The sled test
proposed today is based on the FMVSS No. 214 MDB test of a small
passenger car, replicating the real-world side crashes that occur most
frequently today. The proposed sled test set-up is representative of
the side impact environment in which a CRS would be used in today's
vehicles. The environment is based on the rear seat and side door of
vehicles meeting FMVSS No. 214. Children seated in the rear seat are
benefitting from FMVSS No. 214's requirements: Side door beams and door
and sill structure reinforcements prevent intrusion and enable the
vehicle to better manage the crash energy.\25\
---------------------------------------------------------------------------

    \25\ Side curtain air bags installed pursuant to FMVSS No. 214's
pole test will provide head protection to children who sit high
enough (whether in a CRS or directly on the vehicle seat) to
experience head-to-curtain interaction in a side crash.
---------------------------------------------------------------------------

    Yet, due to their size and fragility, infants and toddlers are
dependent on child restraint systems to augment FMVSS No. 214
protection, and to manage the side crash energy further. In developing
this NPRM, our objectives were to ensure that CRSs provide a minimum
level of protection in side impacts by effectively restraining the
child, preventing harmful head contact with an intruding vehicle door
or CRS structure, and by attenuating crashes forces to the child's
chest.
    e. This rulemaking is issued in furtherance of MAP-21. MAP-21
requires a final rule amending FMVSS No. 213 to improve the protection
of children seated in child restraint systems during side impact
crashes.

VI. Potentially Affected Child Restraints

    Consistent with the principles discussed above, we propose to apply
the side impact test requirements to all CRSs designed to seat children
in a weight range that includes weights up to 18 kg (40 lb). Children
in the 0 to 18 kg (40 lb) group (which encompasses children from birth
to about 4 YO) have a high rate of child restraint use (<1 YO = 98
percent and 1 to 3 YO \26\ = 93 percent according to the 2009 National
Survey of the Use of Booster Seats (NSUBS) \27\), which provides a good
opportunity for improving CRS performance and reducing injuries and
fatalities through a side impact regulation.\28\
---------------------------------------------------------------------------

    \26\ Note that in survey data a child who is 1 day shy of his or
her 4th birth day is still considered a 3 YO. Therefore survey data
representing 1 to 3 YO children include 3 YO children who are nearly
4 YO and at the 40 lb weight limit representing the weight of a 75th
percentile 4 YO child or an average 5 YO child.
    \27\ Pikrell, T.M., Ye, T. Report Number DOT HS 811 377.
September 2010. NSUBS is a probability-based nationwide child
restraint use survey conducted by NHTSA's National Center for
Statistics and Analysis (NCSA).
    \28\ Children between 4 and 12 YO have lower child restraint use
(4 to 7 YO = 55 percent and 8 to 12 YO = 6 percent). Data show that
43 percent of 4 to 7 YO and 78 percent of 8 to 12 YO children use
seat belts.
---------------------------------------------------------------------------

    We believe that focusing at this time on the 0 to 18 kg (40 lb) (0
to 4 YO) age group is highly appropriate for several reasons. Real-
world data show that head injuries are the most common injuries in a
side impact environment. According to McCray,\29\ head injuries in
children 1 to 3 YO are slightly higher than for overall children 0 to12
years of age. Possible countermeasures available to CRS manufacturers
to reduce the risk of head injury are the addition of padding or larger
side ``wing'' structures to keep the child's head contained and to
reduce the severity of the impact. It appears from our testing that
energy-absorbing padding added to the CRS around the head area of the
child and to the side structures (CRS side ``wings'') would enable
forward- and rear-facing CRSs to meet the proposed requirements without
adding any additional structures to the seats.
---------------------------------------------------------------------------

    \29\ 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.
---------------------------------------------------------------------------

    Focusing on children weighing up to 18 kg (40 lb) (0 to 4 YO age
group) also appropriately reflects the near-side impact environment in
which CRSs will be used. Our test results indicated 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
window sill) \30\ of the vehicle door. The sitting height of older
children restrained in CRSs typically positions the head high enough
above the beltline to benefit from the vehicle's FMVSS No. 214 side
impact safety features, such as side window curtain air bags. The need
for a side impact requirement in FMVSS No. 213 may be lessened for
those children. However, when the child's head is below the beltline,
as likely with children weighing up to 18 kg (40 lb) (0 to 4 YO) in
CRSs, there is greater need for FMVSS No. 213 side impact protection,
as less benefit is attained from the vehicle countermeasures.
---------------------------------------------------------------------------

    \30\ 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, usually 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.
---------------------------------------------------------------------------

    Importantly also, due to the absence of an array of side impact
child test dummies, we believe that focusing this NPRM on CRSs designed
for children in a weight range that includes weights up to 18 kg (40
lb) best accords with Vehicle Safety Act requirements, which, among
other factors, require each FMVSS to be ``appropriate for the types of
motor vehicle equipment for which it is prescribed.'' \31\ In FMVSS No.
213's frontal crash program, a 3 YO child dummy (weighing 16.3 kg (36
lb)) is considered representative of children weighing 10 kg to 18 kg
(22 to 40 lb), and is used to test CRSs recommended for children
weighing 10 kg to 18 kg (22 to 40 lb). Similarly, we believe that the
Q3s 3 YO side impact test dummy (weighing 14.5 kg (32 lb)) would be an
appropriate test dummy to evaluate CRSs designed for children weighing
10 kg to 18 kg (22 lb to 40 lb).
---------------------------------------------------------------------------

    \31\ 49 U.S.C. 30111(b).
---------------------------------------------------------------------------

    On the other hand, currently, the 3 YO child dummy used in the
frontal crash program is not used to test CRSs with regard to
performance in restraining children weighing more than 18 kg (40 lb).
This is because the 3 YO test dummy is not considered representative of
children for whom the CRS is recommended. Similarly, we believe that
the Q3s, which has only been made available recently, would not be a
suitable dummy to test the performance of CRSs with respect to children
weighing more than 18 kg (40 lb). The Q3s would not be representative
of children for whom the CRS is recommended, and test data obtained by
use of the ATD would not likely be meaningful as to the performance of
the CRS in restraining

children weighing more than 18 kg (40 lb).
    We request comments on the merits of amending FMVSS No. 213 at this
time to improve the protection of children weighing over 18 kg (40 lb),
assessing performance of the CRSs with the Q3s or by other means. We
also seek comments on whether belt-positioning (booster) seats
recommended for older children have design limitations that might
impede their ability to meet the proposed requirements. We have noticed
that some belt-positioning seats for older children are advertised as
providing side impact protection. We ask manufacturers to provide us
information on the methods they use to demonstrate that their side
impact design features for belt-positioning seats do in fact improve
protection in side impacts.
    There are a number of different types of child restraints designed
for children in a weight range that includes weights up to 18 kg (40
lb). With regard to belt-positioning (booster) seats recommended for
children weighing up to 18 kg (40 lb),\32\ we propose testing the seats
with the Q3s.\33\ The SISA would be equipped with Type II (lap and
shoulder) belts to test the belt-positioning boosters. Belt-positioning
(booster) seats sold for children in a weight range that includes
weights up to 18 kg (40 lb) might have to improve some side wing
structures, but we tentatively believe that the trade-off in possible
increased size of side wing structures and padding and cost of these
belt-positioning seats versus improved side impact protection is
worthwhile for protection of this young child group (children weighing
up to 18 kg (40 lb) (0 to 4 YO age group)). This approach of testing
all CRSs designed to seat children in a weight range that includes
weights up to 18 kg (40 lb), including belt-positioning seats, accords
with MAP-21.
---------------------------------------------------------------------------

    \32\ Currently, FMVSS No. 213 prohibits manufacturers from
recommending belt-positioning seats for children weighing less than
13.6 kg (30 lb).
    \33\ This discussion also applies to convertible or front-facing
child restraint systems that are equipped with an internal harness,
that are also sold for use as a belt-positioning booster once the
child reaches a certain weight or height (the consumer is instructed
to remove the harness when using the CRS as a belt-positioning
seat). Under this NPRM, a CRS that is marketed for use as a belt-
positioning seat for children in a weight range that includes
children weighing less than 18 kg (40 lb) would be tested in the
belt-positioning ``mode'' to the side impact requirements.
---------------------------------------------------------------------------

    On the other hand, we believe that the proposed requirements should
not apply to harnesses. FMVSS No. 213 defines a harness as ``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 of the
child.'' NHTSA tentatively believes that harnesses should be excluded
because of practicability concerns about the ability of the harness to
meet the proposed requirements and because harnesses serve a need in
certain populations. Harnesses would likely not be able to meet the
proposed performance requirements because they do not have a side
structure that can be reinforced and/or padded to mitigate forces on
the Q3s in the side test. At the same time, we recognize that there is
a niche served by harnesses on certain school buses and special needs
buses, one whose needs cannot be met by any other type of CRS. In
addition, the side impact crash environment of a school bus is
significantly different from that simulated by the proposed sled test
procedure (which simulates a near-side impact of a small passenger
car). Accordingly, we propose excluding harnesses from the proposed
side impact requirements.
    Car beds would also be excluded from the proposed requirements. Car
beds do not ``seat'' children but instead restrain or position a child
in a supine or prone position on a continuous flat surface. FMVSS No.
213 requires manufacturers of car beds to provide instructions stating
that the car bed should be positioned in the vehicle such that the
child's head is near the center of the vehicle. We believe that, due to
the supine position and location of the head of the child, the risk of
injury and the injury patterns of children in car beds are much
different from those of children seated forward- or rear-facing. There
is no accident data available that show that benefits would accrue from
applying the proposed side impact protection standard to car beds.

VII. Real World Analysis

    The motor vehicle occupant fatality rate among children 4 YO and
younger has declined from 4.5 in 1975 to 1.54 in 2009 (per 100,000
occupants). This decline in fatality rate is partially attributed to
increased use of child restraint systems. The 2009 NSUBS found that
most (92 percent) children 0 to 7 YO were riding in the rear seats of
vehicles and were restrained in CRSs (98 percent of 0 to 1 YO children,
93 percent of 1 to 3 YO children, and 55 percent of 4 to 7 YO
children).\34\
---------------------------------------------------------------------------

    \34\ Tony Jianquiang Ye and Timothy Pickrell, NHTSA, DOT HS 811
377, September 2010.
---------------------------------------------------------------------------

    According to the 2009 FARS data files, there were 33,808 persons
killed in motor vehicle crashes in 2009, 322 of whom were children aged
4 and younger killed in passenger vehicle crashes. Among the 322 child
occupant fatalities, 92 (29 percent) were unrestrained, 27 (8 percent)
were restrained by vehicle seat belts, 178 (55 percent) were restrained
in CRSs, and 25 (8 percent) had unknown restraint use.\35\
---------------------------------------------------------------------------

    \35\ Children, Traffic Safety Facts--2009 data, DOT HS 811 387,
NHTSA, http://www-nrd.nhtsa.dot.gov/pubs/811387.pdf, last accessed
August 9, 2012.
---------------------------------------------------------------------------

    In 1996, the agency estimated the effectiveness of CRSs and found
the devices to reduce fatalities by 71 percent for children younger
than 1 YO and by 54 percent for toddlers 1 to 4 YO in passenger
vehicles.\36\ For today's NPRM, the agency updated the 1996
effectiveness estimates by conducting a similar analysis using the FARS
data files for the years 1995-2009.\37\ In the updated analysis,\38\
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 YO, the 0
to 1 YO age group was combined with the 1 to 3 YO 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
YO and 43 percent effective among children 4 to 7 YO. In non-rollover
side crashes, CRSs currently in use are 42 percent effective in
preventing fatalities among 0 to 3 YO and 51 percent effective among 4
to 7 YO children.
---------------------------------------------------------------------------

    \36\ ``Revised Estimates of Child Restraint Effectiveness,''
Research Note, supra.
    \37\ Details of the analysis method are provided in the
supporting technical document in the docket for this NPRM.
    \38\ Details of the updated analysis are provided in the
supporting technical document in the docket for this NPRM.
---------------------------------------------------------------------------

    The agency estimates that the lives of 284 children 4 YO and
younger were saved in 2009 due to the use of child restraint systems.
At 100 percent use of child restraint systems for children 0 to 4 YO,
an estimated 372 lives would have been saved in 2009.\39\ This estimate
accounts for consumers' real-world use of child restraints, i.e., these
lives would be saved even when the CRSs are misused.
---------------------------------------------------------------------------

    \39\ Tony Jianquiang Ye and Timothy Pickrell, Child Restraint
use in 2009--Overall Results, NHTSA, DOT HS 811 377, September 2010.
---------------------------------------------------------------------------

    Failure to use proper occupant restraints is a significant factor
in a large 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
\40\ 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.
---------------------------------------------------------------------------

    \40\ 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 and the National Automotive Sampling System-
Crashworthiness Data System (NASS-CDS)) for the years 2005-2009 to
better understand fatalities to children restrained in child restraints
when involved in side crashes.
    First, we categorized the crash cases involving children (0 to 12
YO) 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 YO in Rear Seating Positions of Light Passenger
                                 Vehicles Categorized by Restraint Type and Age
                                                [FARS 2005-2009]
----------------------------------------------------------------------------------------------------------------
                                                                     Age (years)
                   Restraint                    ----------------------------------------------------    Total
                                                   Under 1        1-3          4-7          8-12
----------------------------------------------------------------------------------------------------------------
None...........................................         13.4         39.8           68         91.6        212.8
Adult Belt.....................................          1.8         11.6         57.4         78.2          149
CRS............................................         55.8          106         54.2          4.4        220.4
Unknown........................................          2.8          6.6         12.8         14.6         36.8
                                                ----------------------------------------------------------------
    Total......................................         73.8          164        192.4        188.6          619
----------------------------------------------------------------------------------------------------------------

    Annually, there were 619 crash fatalities among children 0 to 12 YO
seated in rear seating positions of light vehicles. Among these
fatalities, 220 (36 percent) were to children restrained in CRSs (162
were 0 to 3 YO and 58 were 4 to 12 YO). Nearly three-quarters of the
CRS restrained child fatalities were to children 0 to 3 YO.
    As shown in the last column of Table 6, among the 220 fatalities of
children 0 to 12 YO restrained in rear seats of light passenger
vehicles and in CRSs, approximately 32 percent occurred in frontal
crashes, 31 percent in side crashes, 25 percent in rollovers, and 11
percent in rear crashes. Approximately 60 percent of side impact
fatalities (41/68.4) were in near-side impacts. (``Far-side'' position
means the outboard seating position on the opposite side of the point
of impact.)

Table 6--Average Annual Crash Fatalities Among Children 0 to 12 YO in Rear Seating Positions of Light Passenger Vehicles and Restrained in CRSs by Crash
                                                                      Mode and Age
                                                                    [FARS 2005-2009]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Age (years)
                    Crash mode                     --------------------------------------------------------------------      Total        Percent total
                                                           <1              1-3              4-7              8-12
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rollover..........................................             13.8             26.4             13.4              1.4             55               25
Front.............................................             16               35.6             19.8              1               72.4             32
Side..............................................             17.4             34.8             15                1.2             68.4             31
    Near-side.....................................             10.6             20                9.6              0.8             41               18.6
    Far-side......................................              6.8             14.8              5.4              0.4             27.4             12.4
Rear..............................................              8.6              9.2              6                0.8             24.6             11
                                                   -----------------------------------------------------------------------------------------------------
    Total.........................................             55.8            106               54.2              4.4            220.4            100
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Of the side impact crash fatalities among CRS restrained children 0
to 12 YO in rear seating positions, three quarters of near side
fatalities (30.6/41) 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.\41\
The analysis was conducted for three different child age groups (<1 YO,
1 to 3 YO, and 4 to 7 YO) 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).
---------------------------------------------------------------------------

    \41\ 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.
---------------------------------------------------------------------------

    In support of the NPRM, the agency analyzed NASS-CDS for the years
1995-2009 to obtain annual estimates of moderate or higher severity
injuries (AIS 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 YO Children With AIS 2+ Injuries in Rear Seating Positions of Light Passenger Vehicles Involved in Motor
                                                            Vehicle Crashes by Restraint Type
                                                                  [NASS-CDS 1995-2009]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Age (years)
                       Restraint                        ----------------------------------------------------------------      Total       Percent total
                                                             Under 1           1-3             4-7            8-12
--------------------------------------------------------------------------------------------------------------------------------------------------------
None...................................................              26             174             765             969            1934             31.7
Adult Belt.............................................               0              93             722            1550            2365             38.7
CRS....................................................             164             883             422              16            1485             24.3
Unknown if used........................................               1              32             215              66             314              5.1
                                                        ------------------------------------------------------------------------------------------------
    Total..............................................             191            1182            2124            2601            6098            100
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Annually, there were, on average, approximately 6,100 AIS 2+
injuries to children 12 YO and younger seated in the rear seats of
light passenger vehicles with 1,373 of these injured occupants being
younger than 4 YO. Approximately 1,485 CRS restrained children 12 YO
and younger sustained AIS 2+injuries, among which 1,047 (71 percent)
were children younger than 4 YO and 422 (28 percent) were 4 to 7 YO
children.
    The NASS-CDS data files for the years 1995-2009 were further
analyzed to determine crash characteristics. Table 8 presents the
average annual estimates of 0 to12 YO children with AIS 2+ injuries in
rear seating positions of light passenger vehicles. Thirty-one percent
of the children were injured in side crashes, 40 percent in frontal
crashes, and 23 percent in rollover crashes.

  Table 8--Average Annual Estimates of 0 to 12 YO Children With AIS 2+ Injuries in Rear Seating Positions of Light Passenger Vehicles Involved in Motor
                                                              Vehicle Crashes by Crash Mode
                                                                  [NASS-CDS 1995-2009]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Age (years)
              Rollover status, damage type               ----------------------------------------------------------------      Total        Percent of
                                                                <1              1-3             4-7            8-12                            known
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rollover................................................              38             278             372             704           1,392              23
Front...................................................             103             356             777            1138           2,374              40
Side....................................................              34             371             893             652            1950              31
    Near-Side...........................................              24             280             464             438           1,209              19
    Far-Side............................................              10              91             429             214             741              12
Rear....................................................              17             139              82             106             344               6
Other...................................................               0              36               0               1              37               1
                                                         -----------------------------------------------------------------------------------------------
    Total...............................................             192           1,180           2,124           2,601           6,097             100
--------------------------------------------------------------------------------------------------------------------------------------------------------

    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.

  Table 9--Average Annual Estimates of 0 to 12 YO CRS Restrained Children With AIS 2+ Injuries in Rear Seating
              Positions of Light Passenger Vehicles Involved in Motor Vehicle Crashes by Crash Mode
                                              [NASS-CDS 1995-2009]
----------------------------------------------------------------------------------------------------------------
                                                            Age (years)
           Crash mode            ----------------------------------------------------------------      Total
                                      Under 1           1-3             4-7            8-12
----------------------------------------------------------------------------------------------------------------
Rollover........................              28             148              44               0             220
Front...........................              94             310             214              16             634
Side............................              31             307             137               0             475
    Near-side...................              22             253              44               0             319
    Far-side....................               9              54              93               0             156

Rear............................              12              98              26               0             136
                                 -------------------------------------------------------------------------------
    Total.......................             165             863             421              16            1465
----------------------------------------------------------------------------------------------------------------

    For AIS 2+ injured 12 YO and younger child occupants in passenger
vehicles restrained in CRSs in rear seating positions, 15 percent of
the injuries were in rollover events, 43 percent in frontal crashes, 33
percent in side crashes, and 9 percent in rear crashes. Sixty-seven
percent (319/475) 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, we do
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.

VIII. Past NHTSA Efforts

    In the past, NHTSA has explored the possibility of side impact
requirements for child restraints in FMVSS No. 213.
    When NHTSA first considered dynamic testing of child restraints (39
FR 7959; March 1, 1974), the agency proposed a 90 degree lateral impact
simulating a 32 km/h (20 mph) crash. NHTSA proposed that each CRS would
have to retain the test dummy within the system, limit head motion to
483 mm (19 inches (in)) in each lateral direction measured from the
exterior surface of the dummy's head, and suffer no loss of structural
integrity.
    NHTSA withdrew the proposal after testing a number of restraints at
a speed of 32 km/h (20 mph) and at a horizontal angle of 60 degrees
from the direction of the test platform travel. The tests found that
for outboard seating positions, only one of those restraints--one that
required a tether--could meet the lateral head excursion limits that
had been proposed. This was of concern because tethers were widely
unused at that time. Further, the agency found that some restraints
with impact shields, which, the agency stated, performed well in
frontal crashes and which were rarely misused, could not pass the
lateral test even when placed in the center seating position. The
agency decided not to pursue lateral testing of child restraints given
the cost of the design changes that would have been necessary to meet
the lateral test, the problems with misuse of tethers, and the possible
price sensitivity of child restraint sales. (43 FR 21470, 21474; May
18, 1978.)
    In 2002, in response to the Transportation Recall Enhancement,
Accountability and Documentation Act (``TREAD Act'') (Pub. L. 106-414,
114 Stat. 1800), NHTSA issued an advance notice of proposed rulemaking
(ANPRM) to request comments on the agency's work in developing a
possible side impact protection requirement for CRSs (67 FR 21836, May
1, 2002).
    Information indicated that child head injury was prevalent in side
crashes. However, the agency was not able to confirm whether the
majority of injuries and fatalities occur primarily due to direct head
contact with the vehicle interior or other objects in the vehicle, or
whether these injuries and fatalities are a result of non-contact,
inertial loading on the head and neck structure. Due to these unknowns
about head injury causation, the agency considered two side impact
performance tests for child restraints. The tests were modeled after
the simulated side impact test administered by the New South Wales,
Australia, Roads and Traffic Authority (discussed in the next section).
In one test, the CRS had to limit head excursion and HIC \42\ when
oriented at 90 degrees to the direction of sled travel. In the second
test developed by NHTSA, a rigid structure, representing the side of
the vehicle's interior side structure, was positioned adjacent to the
child restraint. Limits on HIC, chest acceleration, a neck injury
criterion and chest deflection were considered.
---------------------------------------------------------------------------

    \42\ Head injury criterion.
---------------------------------------------------------------------------

    The ANPRM requested information on the following areas: (a)
Determination of child injury mechanisms in side impacts, and crash
characteristics associated with serious and fatal injuries to children
in child restraints; (b) development of test procedures, a suitable
test dummy and appropriate injury criteria; and (c) identification of
cost beneficial countermeasures.
    The agency received approximately 17 comments on the ANPRM.
Commenters supported enhancing child passenger protection in side
impacts, but were concerned about the uncertainties with respect to the
three areas highlighted above. A number of commenters believed that a
dynamic test should account for some degree of vehicle intrusion into
the occupant compartment.
    NHTSA withdrew the ANPRM after considering the comments on the
ANPRM and other information. The agency found that for side crashes:
(a) Data were not widely available as to how children are being injured
and killed in side impacts (e.g., to what degree injuries were caused
by intrusion of an impacting vehicle or other object); (b) there was
not a consensus on an appropriate child test dummy and associated
injury criteria for side impact testing; and, (c) potential
countermeasures for side impact intrusion were not identified. NHTSA
determined that an NPRM was not feasible given unknowns about side
crashes involving children in CRSs and the time constraints of the
TREAD Act.

IX. Side Impact Program Developments

    Notwithstanding the ANPRM's withdrawal, NHTSA continued research
into improved side impact protection requirements for child restraints.
    As discussed in this section, the state of knowledge about side
crashes and CRS-restrained children is considerably greater now than it
was in 2002. Information about how restrained children are being
injured and killed in side crashes has become increasingly available in
recent years. In addition, the agency has continued to evaluate test
parameters and potential methodologies to replicate a representative
side impact scenario that could potentially be developed into a dynamic
side impact test procedure.

a. Side Impact Environment for Children

    Sherwood \43\ analyzed fatalities of children under 5 years of age
and found that even in survivable crashes there was intrusion into the
interior space occupied by the child. Arbogast \44\ found intrusion to
be an important causative factor for moderate/serious injury and
suggested that side impact test procedures include intrusion into the
occupant space. Howard \45\ found that struck side child passengers
sustained severe head, torso and extremity injuries, many of them
attributable to direct intrusion.
---------------------------------------------------------------------------

    \43\ Sherwood, et al., 2003, supra.
    \44\ Arbogast, K.B., Chen, I., Durbin, D.R., and Winston, F.K.,
``Injury Risks for Children in Child Restraint Systems in Side
Impact Crashes,'' International IRCOBI Conference on the
Biomechanics of Impact, October 2004.
    \45\ Howard, A., Rothman, L., Moses McKeag, A., Pazmino-
Canizares, J., Monk, B., Comeau, J.L., Mills, D., Blazeski, S.,
Hale, I., and German, A., ``Children in Side-Impact Motor Vehicle
Crashes: Seating Positions and Injury Mechanisms,'' The Journal of
Trauma, Injury, Infection, and Critical Care, Vol. 56, No. 6, pp.
1276-1285, 2004.
---------------------------------------------------------------------------

    Sherwood also found that most side crashes had a longitudinal crash
component and recommended that child restraints be designed to take
into account both longitudinal and lateral components of the direction
of force in a side crash. This finding accords with that found by NHTSA
while developing FMVSS No. 214 (55 FR 45733), where data showed that
during most side impact crashes, the struck vehicle is traveling
forward while being struck on the side.
    Nagabhushana \46\ noted that vehicle crashes involving child
occupants most often had a principal direction of force of 2 o'clock
(60 degrees) or 10 o'clock (300 degrees). Nagabhushana also found that
the average change in velocity in side crashes involving children 1 to
3 YO (in crashes where the child was positioned near-side, on the
struck side of the vehicle) was 23 km/h (14 mph). NHTSA examined NASS-
CDS data files for the years 1995-2009 for side impact crashes of light
vehicles and found that 92 percent of near-side crashes to restrained
children (0 to 12 YO) had a change in velocity of 30 km/h (19 mph) or
lower. This change in velocity is approximately equal to that
experienced by a light vehicle in a FMVSS No. 214 MDB side impact test.
This 92 percent is of all near side crashes involving restrained
children 0-12 years old. These near-side crashes were not only fatal
crashes, but also included those where occupants were not injured or
sustained non-fatal injuries.
---------------------------------------------------------------------------

    \46\ Nagabhushana, V., Morgan, R., Kan, C., Park, J., Kuznetsov,
A., ``Impact Risk for 1-3 Year-Old Children on the Struck Side in a
Lateral crash,'' DOT HS 810 699, April 2007.
---------------------------------------------------------------------------

b. Injury Mechanisms in Side Impact

    McCray (2007) \47\ analyzed the NASS-CDS and Crash Injury Research
and Engineering Network (CIREN) data files for the years 1995-2005 to
better understand injuries to children 1 to 3 YO in side impact
crashes. The study found that children restrained in CRSs exhibited
more head injuries (59 percent) than torso injuries (22 percent) and
injuries to extremities (14 percent). Children in near-side crashes
tended to suffer more severe injuries than those in far-side crashes.
---------------------------------------------------------------------------

    \47\ McCray, et al., 2007, supra.
---------------------------------------------------------------------------

    Arbogast (2004) \48\ queried the Partners for Child Passenger
Safety Study (PCPS) data collected from December 1, 1998 to November
30, 2002 and found that the risk of injury (AIS 2+: moderate or greater
severity) for children restrained in CRSs in near-side impact crashes
was significantly higher (8.9 injured children per 1,000 crashes) than
those in far-side \49\ impact crashes (2.1 injured children per 1,000
crashes) and those in frontal crashes (2.7 injured children per 1,000
crashes).
---------------------------------------------------------------------------

    \48\ Arbogast, et al., 2004, supra.
    \49\ Far-side impacts are side impact crashes where the occupant
is seated away from the struck-side of the vehicle (center seating
position or opposite the struck-side of the vehicle).
---------------------------------------------------------------------------

    NHTSA analyzed NASS-CDS average annual estimates (1995-2009) for
AIS 2+ injuries to children 0 to 12 YO in rear seats. The most common
AIS 2+ injuries among restrained children in near-side impacts were to
the head and face (55 percent), torso (chest and abdomen--29 percent),
upper and lower extremities (13 percent). The most common injury
contacts for AIS 2+ injuries were the side interior (33 percent), the
front seat back (11.12 percent) and the CRS (9 percent).\50\
---------------------------------------------------------------------------

    \50\ In comparison, data showed that the most common AIS 2+
injuries among children restrained in frontal impacts were to the
head and face (42 percent), torso (chest and abdomen--27 percent),
and upper and lower extremities (25 percent). The most common injury
contacts for AIS 2+ injuries were the seat back support (50 percent)
and the belt webbing or buckle (19 percent).
---------------------------------------------------------------------------

    Arbogast (2010) \51\ examined two in-depth crash investigation
databases (CIREN and the PCPS) for rear-seated CRS-restrained children
in side impact crashes who sustained AIS 2+ injuries. Arbogast found
that among the 41 cases examined, 28 children sustained head injuries
and 9 sustained thoracic injuries (lung contusions without rib
fractures). In general, head and thorax injuries were due to contact
with the CRS structure or the door interior. For near- and center-
seated occupants, the head and face were the most common body regions
of injury, followed by the thorax. For far-side occupants, there were
fewer injuries and there was no clear pattern of body region.
---------------------------------------------------------------------------

    \51\ Arbogast, K.B., Locey, C.M., Zonfrillo, M.R., Maltese,
M.R., ``Protection of Children Restrained in Child Safety Seats in
Side Impact Crashes,'' Journal of Trauma, 2010, October, 69(4): 913-
23.
---------------------------------------------------------------------------

c. Global Dynamic Side Impact Tests

    Globally, several organizations have developed or continued work on
side impact test procedures for child restraints.
     Australia and New Zealand's dynamic side impact test
procedure (AS/NZS 1754 Revision 2004) specifies two different side
impact tests. The first test simulates a far-side crash, in which a
bench seat with a CRS attached to it is mounted on a sled at a 90
degree orientation and is subjected to lateral acceleration
representative of that in a side impact vehicle crash. The second test
simulates a near-side crash, incorporating a bench seat mounted at 90
degrees on the sled along with a fixed door mounted at the front of the
sled adjacent to the bench seat. The sled is calibrated to undergo a
velocity change of not less than 32 km/h (20 mph), with a deceleration
of 14-20 g. P-series dummies developed by the Netherlands Organization
for Applied Scientific Research (TNO) are used to test forward-facing
seats and boosters, and the TNO P-series and the TARU Theresa dummy are
used for infant rear-facing restraints. The AS/NZS 1754 regulation
specifies that the child restraints shall not allow any head contact
with any part of the test door. (The P-series ATDs are frontal impact
test dummies. They were not specially designed for use in side impacts.
The TARU Theresa dummy represents a 6-week-old infant and is an
uninstrumented dummy with a weight of only 4 kg (9 lb).)
     Australia's consumer information program rates the
performance of CRSs in side impacts through the ``Child Restraint
Evaluation Program'' (CREP). The test procedure is similar to AS/NZS
1754. CREP utilizes two side impact tests for its CRS rating system;
one test is at a 90 degree impact and the other is at a 66 degree \52\
impact, both with a fixed door structure in place. The velocity of the
sled is 32 km/h (20 mph) and its peak deceleration is 17 g. CREP rates
the child restraint system in the side impact test based on child
restraint durability and structural integrity, dummy retention in the
CRS, and head excursion and contact with the wall.
---------------------------------------------------------------------------

    \52\ Previously this was a 45 degree impact.

---------------------------------------------------------------------------

     Germany's Allgemeiner Deutscher Automobil-Club (ADAC)
adopted a consumer information rating program. The procedure uses a
body-in-white of a VW Golf or Opel Astra. The body-in-white \53\
structure is mounted on a sled at an 80 degree angle. The vehicle door
does not intrude into the passenger area; the door is welded shut and
covered with foam creating a flat door. The sled is decelerated from an
initial velocity of 25 km/h (16 mph) with an 18 g acceleration pulse.
This test method is used to determine ADAC star ratings based on head
containment, head acceleration, chest acceleration, neck moment and
neck force of the Q series dummies and the P10 (P-series, 10 YO child
dummy) for booster seats.
---------------------------------------------------------------------------

    \53\ Body-in-white refers to a stage of automobile manufacturing
in which the car body sheet metal has been welded and assembled but
before the motor and chassis assemblies have been added.
---------------------------------------------------------------------------

     The International Standards Organization (ISO) and TNO
have continued to work on developing a side impact test which uses a
rotating hinged door to simulate door intrusion into the CRS.\54\
---------------------------------------------------------------------------

    \54\ Johannsen, H., et al., ``Review of the Development of the
ISO Side Impact Test Procedure for Child Restraint Systems,'' 20th
International Technical Conference on the Enhanced Safety of
Vehicles, Paper No. 07-0241, Lyon, France, 2007. http://www-nrd.nhtsa.dot.gov/pdf/esv/esv20/07-0241-W30.pdf. Last accessed May
3, 2012.
---------------------------------------------------------------------------

     The World Forum for the Harmonization of Vehicle
Regulations (WP.29) of the European Union (EU) approved Phase I (total
of 3 phases) of a new regulation on child restraint systems in November
2012, which includes a side impact test procedure.\55\ The test
procedure is currently only intended for evaluating CRSs with rigid
ISOFIX anchorages.\56\ The regulation's test procedure consists of a
fixed flat door on a sled that intrudes into a CRS secured on a bench
seat using the ISOFIX anchorages. The relative velocity between the
door and the bench seat at time of impact is approximately 25 km/h (16
mph). The impact is purely lateral with no longitudinal door velocity
component. The ISOFIX anchorages on the test bench are allowed to slide
along the seat up to 250 mm to avoid damage of the attachments and the
test equipment. The CRSs are tested using the Q-series newborn, 1 YO,
1\1/2\ YO, and 3 YO child dummies in accordance with manufacturers'
recommended size of child for the CRS. Injury criteria include head
containment (no contact of the head with the door panel), head
acceleration, and a head injury criterion.
---------------------------------------------------------------------------

    \55\ http://www.unece.org/fileadmin/DAM/trans/doc/2012/wp29/ECE-TRANS-WP29-2012-53e.pdf.
    \56\ The ISOFIX concept originated as a 4-point rigid system,
where four sturdy braces are mounted on the bottom of a child
restraint. Each brace has a latch at its end. Two of the latches
connect, through holes at the vehicle seat bight, to a metal bar in
the seat frame. The other two latches, at the bottom braces, connect
to a bar below the vehicle seat cushion. Alternatives to the concept
4-point ISO system have been developed, including a system that
consists of the CRS having two rigid rear braces at the seat bight
(rather than the 4 points of the original ISOFIX). Some ISOFIX
concepts have included an upper tether, some have included a support
leg (see next footnote, below). FMVSS No. 225's ``LATCH'' system
grew out of the ISOFIX concept, as the lower bars of the LATCH
system are similar to the seat frame bar at the seat bight in
ISOFIX. LATCH requires the CRS to have components that attach to the
vehicle's lower bars, but LATCH does not require the components to
be rigidly attached to the CRS as on a brace. The components may be
attached to the CRS by webbing material. Because of these
differences, a test designed for ISOFIX systems is generally not
appropriate for testing LATCH systems, and vice versa.
---------------------------------------------------------------------------

     European authorities are developing a new consumer
program, ``New Programme for the Assessment of Child Restraint Systems
(NPACS),'' \57\ to create a harmonized program for the evaluation of
ISOFIX universal and ISOFIX semi-universal \58\ child restraints. This
rating program would include a side impact test for CRSs and will
utilize ATDs. Details of the test procedure are not available at this
time, but it is the agency's understanding that, although the eventual
test procedure may share some aspects with the recent ECE regulation,
it will likely not be based on the same test method.
---------------------------------------------------------------------------

    \57\ NPACS is similar to NHTSA's (and the general European) New
Car Assessment Program (NCAP), in that it is a voluntary consumer
information program, rather than a binding regulation. The
difference is that NPACS is being designed to test the CRS itself,
while NCAP focuses on how the vehicle performs.
    \58\ ISOFIX universal CRS means forward-facing restraints for
use in vehicles with positions equipped with ISOFIX anchorages and a
top tether anchorage. ISOFIX semi-universal CRS means: (a) A
forward-facing restraint equipped with a support leg; (b) a rearward
facing restraint equipped with a support leg or a top tether strap
for use in vehicles with positions equipped with an ISOFIX anchorage
system and a top tether anchorage if needed; (c) a rearward facing
restraint, supported by the vehicle dashboard, for use in the front
passenger seat equipped with an ISOFIX anchorage system; or (d) a
lateral facing position restraint equipped, if needed, with an anti-
rotation device for use in vehicles with positions equipped with an
ISOFIX anchorage system and a top tether anchorage, if needed.
---------------------------------------------------------------------------

     Takata developed a sled test buck for testing child
restraints in a side impact environment. The buck has two moving
fixtures: The sled buck itself and the sliding ``vehicle'' seat on
which the child restraint is attached. The sliding ``vehicle'' seat is
mounted to a rail system, along with a ``side door'' structure rigidly
mounted to the sled buck structure. The details of this test procedure
are described more fully in section IX.

d. Side Impact Test Dummy

    The development of a specially-designed child side impact test
dummy, the Q3s, has provided an important tool for evaluating CRSs in
side impact. 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. The Q3s is more fully
discussed in the 49 CFR Part 572 NPRM.

X. Developing NHTSA's Side Impact Test

    The state of knowledge and the practicability of measures that can
be taken to improve side impact protection are now sufficient for NHTSA
to propose a reasonable and realistic side impact test for
incorporation into FMVSS No. 213.
    Based on the information that has become available since the 2002
ANPRM, we tentatively conclude that a side impact is best replicated if
the test procedure reflects and replicates dynamic elements of both the
striking and struck vehicle in a vehicle-to-vehicle crash. We believe
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. Specification of
these parameters, based on actual vehicle crash characteristics, would
enable the realistic simulation of the relative velocity between the
intruding door and the CRS.
    Selection of these parameters is consistent with the findings from
other researchers (see Side Impact Environment for Children, section
IX, supra) that found the change in velocity, the level of door
intrusion, and the impact angle to be significant factors of near-side
impact crashes involving children. In addition, the test bench and door
geometry and vehicle seat and door padding characteristics are
important in a side impact test, to ensure these are representative of
the vehicle rear seat environment.

a. Assessment of Existing Global Efforts

    In order to build on existing efforts, NHTSA reviewed the above
procedures and regulations developed globally that 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 has not proposed it, mainly because the procedure does not simulate
the intruding door, which we believe 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 to be 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.
    Germany's ADAC test procedure lacks an intruding door. Further, the
vehicles represented by the body-in-white in Germany's ADAC test
procedure are limited, and do not represent the range of vehicles in
the U.S. fleet that we would like to have represented in our side
impact test to safeguard child passengers in the U.S.
    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 reportedly results in poor
repeatability.\59\ In addition, this test procedure does not include a
longitudinal velocity component to the intruding door, which is present
in most side impacts and which, we believe, should be replicated in the
FMVSS No. 213 test.
---------------------------------------------------------------------------

    \59\ Sandner, V., et al., ``New Programm for the Assessment of
Child Restraint Systems (NPACS)--Development/Research/Results--First
Step for Future Activities?,'' 21st International Conference on the
Enhanced Safety of Vehicles, Paper Number 09-0298, 2009. http://www-nrd.nhtsa.dot.gov/pdf/esv/esv21/09-0298.pdf. Last accessed on June
11, 2012.
---------------------------------------------------------------------------

    The EU's test procedure did not appear appropriate since the test
is 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 available on CRSs in the U.S., and, due to the differences in to
the two systems discussed above, a test designed for one type of system
will not produce useful results for testing the other system. Further,
the test procedure does not seem to produce a representative
interaction between the door and CRS during a side impact. The NHTSA-
developed test procedure replicates a real-world T-bone type
intersection collision, involving two moving vehicles, with door
intrusion. In contrast, the European test with the sliding ISO
anchorages is a purely lateral impact (stationary vehicle impacted
laterally by another vehicle) and it does not correctly represent the
door intrusion and door to child restraint interaction in real world
side crashes, In addition, the sliding anchors in the European test
allow for the child restraint to slide away from the impacting door,
which also causes the European test be less reflective of a real-world
crash than the test proposed in today's NPRM. The European test is
likewise sensitive to the friction of the sliding anchorages, which may
introduce variability in the test results.\60\ Finally, the European
procedure uses the Q series dummies, which are frontal crash dummies.
NHTSA evaluated the Q3 dummy and has tentatively concluded that the Q3
dummy does not have adequate biofidelity in lateral impact, in contrast
to the Q3s dummy we propose, which is designed for side impacts.
---------------------------------------------------------------------------

    \60\ Hynd, et al., ``Analysis for the development of legislation
on child occupant protection,'' TRL, July 2010.
---------------------------------------------------------------------------

    The NPACS consumer program for side impact is still undergoing
development and the details of the sled test procedure and dummies are
not available.

b. Takata Test Procedure

    In 2007, the agency began evaluating the Takata sled test procedure
for evaluating child restraints in side impact.\61\ The 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
(striking vehicle traveling at 48 km/h (30 mph) impacting the struck
vehicle traveling at 24 km/h (15 mph), which accounts for approximately
92 percent of near-side crashes involving restrained children (0 to 12
YO children in all restraint environments--seat belts and CRSs). The
procedure includes an intruding door and can simulate the relative
velocity between the CRS and the intruding door. It can also be easily
modified to change the impact angle to introduce a longitudinal
component present in the FMVSS No. 214 tests.
---------------------------------------------------------------------------

    \61\ Takata made a presentation on its side impact test
procedure during a February 8, 2007 NHTSA public meeting. The
meeting concerned: Improving LATCH, CRS side impact safety, and
LATCH education. See meeting notice, 72 FR 3103, January 24, 2007,
Docket No. NHTSA-2007-26833. NHTSA also published two papers on the
agency's research and testing on the Takata test procedure. See
Sullivan 2009 and Sullivan 2011, infra.
---------------------------------------------------------------------------

    In its preliminary evaluation of the Takata test protocol, after
making minor modification to the test parameters,\62\ NHTSA determined
that the test procedure was repeatable 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.\63\
---------------------------------------------------------------------------

    \62\ Sullivan, 2009, supra.
    \63\ Sullivan et al., ``NHTSA's Evaluation of a Potential Child
Side Impact Test Procedures,'' 22nd International Conference on the
Enhanced Safety of Vehicles, Paper No. 2011-0227 (2011).
---------------------------------------------------------------------------

    The Takata procedure is based on an acceleration sled with a test
buck consisting of a sliding ``vehicle'' seat mounted to a rail system,
along with a ``side door'' structure rigidly mounted to the sled buck
structure. The vehicle seat and side door are representative of today's
passenger vehicles. Aluminum honeycomb is mounted below the side door
structure. The sliding vehicle seat is positioned sufficiently away
from the side door to allow the sled to reach a desired velocity prior
to the sliding vehicle seat coming into contact with the side door and
aluminum honeycomb. The purpose of the design is for the side door
structure to impact the sliding ``vehicle'' seat at a specified speed,
at which time the aluminum honeycomb begins to crush. The door contacts
the CRS about the same time as the honeycomb contacts the sliding
``vehicle'' seat. The honeycomb characteristics are selected such that
the desired sliding seat acceleration is achieved. The procedure is
illustrated in Figure 1 below.

[GRAPHIC] [TIFF OMITTED] TP28JA14.000

    After considering the Takata test procedure, NHTSA selected the
test method as a basis for developing a side impact test for evaluating
CRS performance.

XI. The Proposed Test Procedure

    As shown above, the proposed test buck consists of a sliding
``vehicle'' seat and ``side door'' rigidly mounted to the

acceleration 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 coming into contact with the
sliding ``vehicle'' seat structure. The parameters of the test buck and
the honeycomb could be tuned to simulate the MDB test of FMVSS No. 214.
    The agency examined data from FMVSS No. 214 MDB compliance tests to
identify kinematic characteristics of the vehicle test that should be
replicated in the sled test environment so that the latter is
representative of the crash experience of a child restrained in a CRS
in the rear seat. The following sled kinematic parameters were
identified: (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 velocity; and (3) the impact angle of the door with the
sliding seat (to replicate the longitudinal component of the direction
of force).
    NHTSA selected and analyzed several FMVSS No. 214 MDB tests of
small passenger vehicles to determine the test parameters and test
corridors representative of the target crash environment. The agency
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 YO in
light vehicles, as estimated by NHTSA using the NASS-CDS datafiles. In
order 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.

a. Sled Kinematic Parameters

1. Sliding Seat Acceleration Profile (Representing the Struck Vehicle)
    To obtain a target acceleration pulse for the sliding seat that
represents the motion of the struck vehicle, the right rear sill (the
opposite side of impact) lateral (Y-axis) acceleration of ten small
vehicles in FMVSS No. 214 tests were analyzed.\64\ The right rear sill
accelerations were averaged to derive a typical struck vehicle
acceleration corridor for small sized vehicles. Figure 2 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 2 is a
representative sliding seat acceleration pulse.
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    \64\ Sullivan et al., 2009.
    [GRAPHIC] [TIFF OMITTED] TP28JA14.001

    To obtain the sliding seat velocity (representing the motion of the
struck vehicle), the right rear sill lateral (Y-axis) accelerations of
the ten small vehicles were integrated to calculate the velocity. The
results showed a change in velocity of approximately 26 to 29 km/h (16
to 18 mph).
2. Door Velocity
    The door velocity (which represents the struck vehicle door
velocity), was obtained from the integration of door acceleration data
from four of the ten previously selected FMVSS No. 214 compliance tests
(only these four vehicles were tested with accelerometers installed on
the door).\65\ 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). 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 acceleration profile of the impacting door need not be specified as
long as its velocity during the interaction with the sliding seat and
child restraint system is maintained within specified velocity
tolerances. The door velocity should be 31 km/h (19.3 mph) prior to the
honeycomb contacting the sliding seat structure.
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    \65\ Id.

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    The relative velocity profile of the intruding door with respect to
the sliding seat from the time the door first contacts the sliding seat
structure to the time the sliding seat and the door reach a common
velocity was determined from sled simulations with a door impact
velocity of the 31 km/h (19.3 mph) in the direction of the sliding seat
motion and a sliding seat acceleration profile shown in Figure 2.
Figure 3 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. The upper and lower boundaries of the relative door
velocity represent the maximum and minimum values of the cluster of
relative door velocity profiles in these sled tests.
[GRAPHIC] [TIFF OMITTED] TP28JA14.002

    Today's NPRM only proposes an acceleration profile for the sliding
seat and a door impact velocity but does not propose a relative door
velocity profile so as not to over specify the test environment.
However, a door velocity profile with respect to the sliding seat may
be desirable to ensure reproducible interaction of the intruding door
with the child restraint in different types of sled systems. We are
requesting comments on the need for specifying a relative door velocity
profile to improve reproducibility of the test procedure. Depending on
whether we receive information sufficiently supporting such a velocity
profile, we may include one in the final rule.
3. Sled Buck Angle (Replicating Longitudinal Component of the Direction
of Force)
    The ten small vehicle FMVSS No. 214 tests were used to determine
the impact angle of the sled buck. The right rear sill acceleration
signals on both the longitudinal (X-axis) and lateral (Y-axis)
directions were integrated to obtain the X and Y vehicle velocities.
These velocities were used to calculate the angle of the resultant
deceleration with respect to the lateral axis of the vehicle during the
crash event.\66\ The time period of interest was determined to be 5 to
60 ms, because this represents the typical time from initial motion of
the struck vehicle through peak loading on the near-side occupant.
---------------------------------------------------------------------------

    \66\ Sullivan et al., 2009.
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    A reference frame was used in which a pure left-to-right lateral
impact was zero degrees and a pure frontal impact was 90 degrees. The
mean angles over the time period of interest for the ten vehicles
ranged from 4 to 15 degrees, while the angle at any specific time
ranged from -8 to 22 degrees across the ten vehicles. From these
ranges, the agency decided to perform tests within a range of 0 to 20
degrees. These tests (at 0, 10, 15 and 20 degrees) were performed in an
effort to evaluate the effect of the test buck's impact angle on dummy
kinematics and injury responses. Based on the tests and on the average
impact angle computed from the vehicle right rear sill velocities of
MDB-to-vehicle crash tests, we selected a 10 degree impact angle as the
most appropriate. NHTSA also conducted sled tests at different impact
angles (0, 5, 10, and 20 degrees) using the Takata sled procedure to
compare them to four MDB crash tests (discussed in a later section)
performed using the Q3s dummy restrained in a CRS in the rear seat
behind the driver. We 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.\67\
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    \67\ Sullivan et al. (2009).
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b. Rear Seat Environment Parameters

    The proposed 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. To ensure that the sliding ``vehicle'' seat and side door
would be representative of today's passenger vehicles, NHTSA conducted
a vehicle survey to examine the geometry and contact characteristics of
present day vehicle rear seats, to select the geometry and material
characteristics that are necessary to replicate the physical
environment of a typical rear seat in a side impact test. NHTSA
identified the following rear seat features to replicate in the SISA:
Rear seat geometry, rear seat cushion stiffness, and door shape (height
of window, armrest thickness, door padding). More information about the
vehicle survey can be found in a technical report that has been placed
in the docket.
    NHTSA also performed a series of sled tests to undertake a
sensitivity analysis to better understand the effect of the sled test
parameters and sled system configuration on dummy responses. The
parameters evaluated were the seat cushion stiffness, door padding
stiffness, presence of armrest, and window sill height. Details of the
findings of the sensitivity analysis are discussed in Sullivan (2011),
supra, and are summarized in the discussion below and in the docketed
technical report.
1. Rear Seat Cushion Stiffness
    In the vehicle survey, NHTSA 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, ECE R.44, and the NPACS
programs.\68\ The 13 vehicles selected were a mix of different vehicle
manufacturers and different vehicle types (passenger cars, sport
utility vehicles, etc.). The NPACS cushion foam was evaluated even
though the NPACS rating system is only in draft form, because European
efforts to upgrade ECE R.44 are considering the use of NPACS foam for
the seat cushion.\69\
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    \68\ Id.
    \69\ LeClaire, M., and Cheung, G., ``NPACS (New Programme for
Assessment of Child restraint Systems, Phase 1 Final Report'' PPAD
9/33/128, Prepared for the Department of Transport, U.K., March
2006.
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    Measurements were taken at various locations on the rear seat
cushion of vehicles in quasi-static compression tests using an
indentation plate.\70\ The FMVSS No. 213 foam was found to be softer
than all the vehicle seat foams surveyed. The NPACS and ECE R.44 foams
were stiffer than the FMVSS No. 213 foam, and more representative of
the vehicles selected in this study.
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    \70\ Id.
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    In NHTSA's sensitivity analysis (see docketed technical report), we
conducted sled tests with the Q3s to determine the effect of the seat
cushion stiffness on dummy readings and CRS performance. Three CRS
models were evaluated (Evenflo Triumph Advance DLX, Maxi-Cosi Priori XP
and Graco SafeSeat Step2/Cozy Cline). The FMVSS No. 213 foam (with
vinyl cover) and the ECE R.44 foam (with cloth cover) were used in this
series of tests.\71\ The results of the evaluation indicated that seat
cushion foam stiffness had little effect on the dummy responses in
these side impact tests.
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    \71\ Sullivan et al. (2011).
---------------------------------------------------------------------------

    Based on the above, the agency is proposing 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 is more representative of the current rear seats
in the vehicle fleet than the FMVSS No. 213 cushion foam. The agency
prefers the ECE R.44 foam over that of the NPACS foam because, although
the two foams are similar in stiffness, the ECE R.44 foam is more
readily available than the NPACS foam. Further, the NPACS procedure is
still in draft form.
    The agency has 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, the agency's plans include developing a test bench seat with
seat cushion stiffness that has characteristics of seat cushions in
recent vehicle models.\72\ The agency will 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. In the meantime, the agency is currently proposing to use the ECE
R.44 foam for the sliding bench seat in the side impact sled. While our
current test data indicate that seat cushion foam stiffness has little
effect on the dummy responses in this side impact test procedure, we
request comment on the proposed seat cushion foam and seat cushion
assembly.
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    \72\ See also MAP-21, Sec.  31501(b), ``Frontal Impact Test
Parameters.'' Paragraph (1) states that, not later than 2 years
after the date of enactment of MAP-21 (July 6, 2012), the Secretary
shall commence a rulemaking proceeding to amend the standard seat
assembly specifications under FMVSS No. 213 ``to better simulate a
single representative motor vehicle rear seat.'' Paragraph (2)
states that not later than 4 years after the date of enactment of
MAP-21, the Secretary shall issue a final rule pursuant to paragraph
(1).
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2. Rear Seat Door Stiffness
    To determine the sled door padding characteristics, we impact-
tested eight vehicle doors using a Free Motion Head (FMH) (see the
docketed technical report and Sullivan (2011)). The FMH impact tests
consisted of a 3.5 kg (7.7 lb) child head form launched horizontally
towards the door at 24 and 32 km/h (15 and 20 mph, respectively), which
are the FMH impact test velocities used to test vehicle interiors in
FMVSS No. 201, ``Occupant protection in interior impact'' (49 CFR
571.201).
    The FMH was directed at different locations on the door where the
head of the dummy was most likely to make contact. That is, the impact
points were selected based on the center of gravity and top of the head
locations of the Hybrid III (HIII) 3 YO child ATD, the HIII 6 YO child
ATD, and the HIII 10 YO child ATD seated on the vehicle seat. The
impact points were determined by tracking the location of head-to-door
contact of these different sized ATDs when seated in the rear seat of a
vehicle and leaned forward and laterally towards the door. Based on the
results from the FMH tests of the eight vehicles, three foams
(described as ``stiff,'' ``average'' and ``soft'' foams) spanning the
range of vehicle door padding FMH impact characteristics were selected.
    In NHTSA's sensitivity analysis (see technical report), we
conducted a series of sled tests with the Q3s to assess the effect of
door padding stiffness on the performance of the two CRS models (Graco
Safe Seat Step 2 and Maxi Cosi Priori XP). ``Soft'' (United Foam
 2), ``average'' (Dow Ethafoam 220), and ``stiff'' (United
Foam  4) foam were used in 51 mm (2 in) thick padding applied
to the simulated door wall panel.\73\ Results showed that the door
stiffness had little effect on dummy performance. The door stiffness
had little effect on the Q3s dummy's HIC15 and chest
deflection results, when restrained in the Graco SafeSeat Step 2 and
Maxi-Cosi Priori XP seats, for the soft, average, and stiff door panel
foams.
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    \73\ Sullivan et al. (2009).
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    Given the above information, the agency is proposing that the door
of the SISA comprise of 51 mm (2 in) thick foam of ``average''
stiffness, so as to be representative of the average rear seat
characteristics. In addition, the foam material with average stiffness
(Dow Ethafoam 220) is of lower cost compared to the other foams, is
relatively easy to obtain commercially, and is relatively fungible, in
that other materials with similar physical properties could easily be
used in its place.
3. Rear Seat Environment Geometry
    The agency surveyed 2010 model year passenger vehicles (passenger
cars, SUVs, vans) to obtain dimensional

characteristics of rear seat attributes that could affect the
performance of a CRS in the rear seat compartment.\74\ These attributes
were: Seat back angle, seat pan angle, beltline height (from
approximately the vehicle seat bight (i.e., the intersection of the
seat cushion and the seat back)), height of the top of the armrest
(from the seat bight), and armrest thickness (protrusion of the armrest
from the door).\75\ The agency measured the seat and door geometry,
position, and dimensions using a Seat Geometry Measuring Fixture
(SGMF).\76\ The SGMF was positioned on the centerline of a rear seating
position and measurements were made with respect to point A (center of
the hinge) of the SGMF.
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    \74\ See Aram et al., ``Vehicle Rear Seat Study--Technical
Report, NHTSA, 2013,'' which is in the docket for this NPRM.
    \75\ The original Takata sled buck did not include an armrest.
We modified the sled buck to include an armrest.
    \76\ The SGMF was fabricated using two 2 x 4 wood blocks (600 mm
x 88 mm x 38 mm) and a three inch hinge. Photographs of the SGMF are
in the report by Aram et al. (2013), supra.
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Seat Back and Seat Pan Angle
    The seat back angle of the vehicles surveyed ranged from 9 to 28
degrees. The average was 20 degrees with a standard deviation of 4
degrees (see Sullivan et. al (2011) and technical report). The seat pan
angle (the angle of the seat cushion to the horizontal) ranged from 7
to 23 degrees. The average seat pan angle was 13 degrees with a
standard deviation of 4 degrees.
    The original Takata buck had a seat back angle and a seat pan angle
of 20 and 15 degrees, respectively. Both the seat back angle and the
seat pan angle are well within the ranges found in NHTSA's vehicle
survey, and are the same as the ECE R.44 bench seat. Therefore, these
angles were adopted in the SISA.
Armrest Thickness
    The armrest thickness (protrusion of armrest in the door) for the
25 vehicles surveyed ranged from 25 mm to 105 mm (1 in to 4.1 in). One
vehicle was at or below 50 mm (2.1 in), 8 vehicles were between 51 mm
and 70 mm (2.0 in and 2.75 in), 10 vehicles were between 71 mm and 80
mm (2.75 in and 3.1 in), and 5 vehicles were above 81 mm (3.1 in). One
vehicle had no armrest.
    The armrest thickness selected for the SISA sled system consists of
a 64 mm (2.5 in) thick padding material attached to a 51 mm (2 in)
thick door panel. The 64 mm (2.5 in) thickness of the armrest foam is
within the range of armrest thickness from surveyed vehicles.
Beltline and Armrest Heights
    The beltline (window sill) and top of the armrest heights of the 24
surveyed vehicles were measured using the SGMF with respect to point A
(center of the hinge of the SGMF) (see Figure 4).
[GRAPHIC] [TIFF OMITTED] TP28JA14.003

    The survey showed that the beltline heights varied between 413 mm
and 566 mm (16.2 in and 22.2 in) in height and the armrest heights
varied between 122 mm and 349 mm (4.8 in and 13.7 in) with respect to
point A. A 489 mm (19.2 in) beltline height and a 238 mm (9.3 in)
armrest height were found to be about the median values of the