Federal Motor Vehicle Safety Standards; Child Restraint Systems Denial of Petition for Rulemaking |
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Raymond R. Posten
National Highway Traffic Safety Administration
8 September 2020
[Federal Register Volume 85, Number 174 (Tuesday, September 8, 2020)]
[Proposed Rules]
[Pages 55396-55398]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-17595]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
[Docket No. NHTSA--2020--0077]
Federal Motor Vehicle Safety Standards; Child Restraint Systems
Denial of Petition for Rulemaking
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation.
ACTION: Denial of petition for rulemaking.
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SUMMARY: This document denies a petition for rulemaking from SafeGuard/
IMMI (formerly Indiana Mills and Manufacturing, Inc.) and C.E. White
requesting that NHTSA amend Federal Motor Vehicle Safety Standard
(FMVSS) No. 213, ``Child restraint systems,'' to provide for ``school
bus built-in belt-positioning seats.'' Under the petitioners' suggested
amendment, a school bus built-in belt positioning seat would be a type
of ``booster seat'' and would consist of a school bus seat with a lap/
shoulder belt and a shoulder belt height adjuster. The agency is
denying the petition because under the requested amendment, designs
would be permitted that do not provide the full benefits of booster
seats, namely the proper positioning of the child on the vehicle seat
to improve the fit of the lap belt to mitigate the risk of abdominal
injuries in a crash.
DATES: September 8, 2020.
ADDRESSES: National Highway Traffic Safety Administration, 1200 New
Jersey Avenue SE, Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: Shashi Kuppa, Office of
Crashworthiness Standards, National Highway Traffic Safety
Administration, 1200 New Jersey Avenue SE, Washington, DC 20590,
telephone: 202-366-3827, or Deirdre Fujita, Office of the Chief
Counsel, National Highway Traffic Safety Administration, 1200 New
Jersey Avenue SE, Washington, DC 20590, telephone: 202-366-2992, fax:
202-366-3820.
SUPPLEMENTARY INFORMATION:
The Petition
On January 15, 2013, the agency received a petition for rulemaking
from SafeGuard/IMMI and C.E. White requesting that NHTSA amend FMVSS
No. 213 to include the following definition in section S4, Definitions:
``School bus built-in belt-positioning seat means a passenger seat used
on school buses that is equipped with an integrated Type II seat belt
that includes a torso belt height adjuster.'' A Type 2 (or Type II)
seat belt assembly is a combination of pelvic and upper torso
restraints, i.e., a lap/shoulder belt.\1\ The seat belt height adjuster
developed by the petitioners is a clip on the shoulder belt loop that
can be moved along the shoulder belt webbing. The petitioners would
like to certify their school bus seats with lap/shoulder belts and
shoulder belt height adjusters as compliant with FMVSS No. 213's
requirements for built-in booster seats.
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\1\ See FMVSS No. 209, ``Seat belt assemblies,'' 49 CFR 571.209
S3, Definitions.
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Background on Booster Seats and Belt-Positioning Seats
Booster seats are one of several types of child restraint systems
used for child passenger protection before the child is large enough to
use the vehicle seat belt alone. A belt-positioning seat is a type of
booster seat under FMVSS No. 213.\2\ NHTSA recommends that 4 to 7-year-
[[Page 55397]]
old children be restrained in booster seats when they no longer fit in
their forward-facing harnessed child restraints.\3\ Booster seats lift
(boost) and reposition the child such that vehicle seat belts (designed
to fit adults) are routed appropriately relative to the child's body.
For the seat belt to fit properly, the lap belt must lie entirely below
the top of the pelvis and touch or lie flat across the upper thighs,
and the shoulder belt should lie snugly across the shoulder and chest
and not cross the neck or face.
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\2\ Under FMVSS No. 213 (S4), ``booster seat'' means ``either a
backless child restraint system or a belt-positioning seat.''
``Belt-positioning seat'' means ``a child restraint system that
positions a child on a vehicle seat to improve the fit of a vehicle
Type II belt system on the child and that lacks any component, such
as a belt system or a structural element, designed to restrain
forward movement of the child in a forward impact.'' The petitioners
would like to have their product considered a kind of ``belt-
positioning seat.'' For simplicity, hereafter in this document, the
term ``booster seat'' means ``belt-positioning seat.''
\3\ https://www.nhtsa.gov/equipment/car-seats-and-booster-seats#age-size-rec.
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An important function of a booster seat is to raise the child up
relative to the vehicle seat belt to improve seat belt fit.\4\ With a
booster seat, the lap belt is positioned such that it loads and
restrains the strong bones of the pelvis. Without a booster seat, the
lap belt is not positioned effectively and the occupant can slide under
the lap belt during deceleration, resulting in the seat belt loading
the abdomen, vulnerable internal organs and spine instead of the
pelvis. This event is called ``submarining.'' Elevating the position of
the child upwards relative to where the lap belt is anchored increases
the lap belt angle with respect to the horizontal plane. A steeper lap
belt angle is better because it makes it harder for the child to slide
under the lap belt (submarine) in a crash. Additionally, boosting the
child compensates for the shorter torso of a child by positioning the
child such that the shoulder belt is away from the neck and restrains
the child through the shoulder structure in a crash.
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\4\ Klinich, K., Manary, M., Weber, K., ``Crash Protection for
Child Passengers: Rationale for Best Practice,'' University of
Michigan Transportation Research Institute Research Review, January-
March 2012, Volume 43, No. 1, ISSN 0739 7100. Available at http://www.umtri.umich.edu/content/rr_43_1.pdf.
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Booster seats may also have seat belt guides to position the
shoulder belt midway between the neck and arm, not so far outboard that
it is at the edge of the shoulder or so far inboard that it is rubbing
the neck. However, because belt fit is improved just by boosting the
child upward, many booster seats work well even if they lack shoulder
belt adjustability or belt guidance.\5\
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\5\ Arbogast KB, Jermakian JS, Kallan MF, and Durbin DR. (2009).
Effectiveness of Belt-positioning Booster Seats:
An Updated Assessment Pediatrics 124:1281-1286.
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The second benefit of booster seats is improving occupant posture
so the child is more likely to be ``in position'' in a crash, similar
to an older occupant. Ideally, to best distribute crash forces, the
occupant is seated in an upright position with the back of the torso
resting against the seat back, the pelvis at the seat bight, and the
knees bent over the front of the seat cushion. However, several studies
have documented that the rear seats of most vehicles are too deep for
children to sit upright with their knees bent over the edge of the seat
and with their back fully supported for comfort.6 7 8
Consequently, children generally scoot forward so their legs can bend
over the front of the seat in a comfortable position and then recline
themselves rearward to rest against the seat back. A booster seat
provides the child with a seat cushion length that is more fitted to
the child's upper leg length. With a booster, a child's legs can bend
comfortably over the end of the booster while the child's back rests
against the seat back. A booster seat helps the child remain upright
and in position.
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\6\ Huang S and Reed M. (2006). Comparison of Child Body
Dimensions with Rear Seat Geometry. SAE Technical Paper 2006-01-
1142, 2006, doi:10.4271/2006-01-1142.
\7\ Klinich KD, Pritz HB, Beebe MS, Welty K, Burton RW. (1994).
Study of older child restraint/booster seat fit and NASS injury
analysis. DOT/HS 808 248. National Highway Traffic Safety
Administration, Vehicle Research and Test Center, East Liberty, OH.
\8\ Bilston LE, Sagar N. (2007). Geometry of rear seats and
child restraints compared to child anthropometry. Stapp Car Crash
Conference J 51:275-98.
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Analysis of the Petition
NHTSA believes that children would be less protected under the
suggested amendment. The petitioners' language would allow designs that
unreasonably reduce the full benefits of booster seats, namely the
proper positioning (boosting) of the child on the vehicle seat to
improve the fit of the lap belt to mitigate the risk of abdominal
injuries in a crash. The suggested amendment would permit designs that
do not offer any seat cushion adjustability. The child could sit
directly on the vehicle seat.
Booster seats are designed to raise the child with respect to the
vehicle seat to improve lap belt fit, as raising the child positions
the lap belt entirely below the top of the pelvis and touching or lying
flat across the upper thighs. Improved lap belt fit reduces the risk of
submarining and abdominal injury.9 10 The suggested language
would permit devices to be certified as ``booster seats'' even though
they lack any feature that reduces the risk of abdominal injuries.
NHTSA believes adopting the suggested language would not be in the
interest of safety as the devices do not provide the full benefits of a
booster seat.
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\9\ Jermakian JS, Kallan MJ, Arbogast KB. (2007). Abdominal
injury risk for children seated in belt-positioning booster seats.
20th International Technical Conference on the Enhanced Safety of
Vehicles, Paper No. 07-0441.
\10\ Jermakian JS, Locey CM, Haughey LJ, Arbogast. KB (2007).
Lower extremity injuries in children
seated in forward facing child restraint systems. Traffic Injury
Prevention, 8:171-179, DOI: 10.1080/15389580601175250.
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Further, as discussed above, booster seats contribute to occupant
protection by improving occupant posture so the child is more likely to
be ``in position'' in a crash.\11\ When children recline themselves
rearward on the seat to bend their knees comfortably over the edge of
the seat, the risk of submarining under the belt in a crash increases.
With the child in the reclined position, the lap portion of the seat
belt can slide upward during a crash and intrude into the child's soft
upper abdomen, thus increasing the likelihood of abdominal injury.
Under the suggested amendment, designs could be introduced that have no
seating platform with an appropriate cushion length. These designs
would not have the raised seat cushion that ensure the child would be
better positioned to ride down crash forces in a manner that best
minimizes injury.
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\11\ Klinich, K., Manary, M., Weber, K., ``Crash Protection for
Child Passengers: Rationale for Best Practice,'' supra.
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Field data have shown booster seats to be effective in reducing
child passenger injuries. Children ages 4 to 8 using lap/shoulder belts
alone have been found to be at higher risk of abdominal injury due to
seat belt interaction compared to children using booster seats.\12\ The
agency's analysis of real world crash data \13\ indicates that, among
children between the ages of 4 to 8 years old, there is a 14 percent
reduction in injury risk when restrained in booster seats versus when
directly in the vehicle's lap/shoulder belts. The petition's language
would allow designs that lack the defining features of booster seats
that have been critical to their functionality transitioning the child
to the vehicle's lap/shoulder belt system. The suggested language would
facilitate designs that reduce the safety benefits of booster seats.
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\12\ Durbin DR, Chen I, Smith R, Elliott MR Winston FK (2005).
Effects of seating positon and appropriate restraint use on the risk
of injury to children in motor vehicle crashes. Pediatrics
115(3):e305-9.
\13\ Siviniski, R., ``Booster Seat Effectiveness Estimates Based
on CDS and State Data,'' NHTSA Technical Report, DOT HS 811 338,
July 2010. http://www-nrd.nhtsa.dot.gov/Pubs/811338.pdf. Last
accessed on October 10, 2017.
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Conclusion
NHTSA has reviewed the petition for rulemaking submitted by
SafeGuard/IMMI and C.E. White requesting that NHTSA amend FMVSS No. 213
to include a definition for ``school bus
[[Page 55398]]
built-in belt-positioning seat.'' The agency is denying the request
because the language that the petitioner would introduce would
unreasonably reduce safety by permitting designs that do not address
the risks of submarining and abdominal injury that booster seats
presently address.
For these reasons and in accordance with 49 U.S.C. 30162 and 49 CFR
part 552, the petition for rulemaking from Safeguard/IMMI and C.E.
White is denied.
Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166;
delegation of authority at 49 CFR 1.95 and 501.8.
Issued in Washington, DC, under authority delegated in 49 CFR
1.95 and 501.8.
Raymond R. Posten,
Associate Administrator for Rulemaking.
[FR Doc. 2020-17595 Filed 9-4-20; 8:45 am]
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