Federal Motor Vehicle Safety Standards; Seating Systems, Occupant Crash Protection, Seat Belt Assembly Anchorages, School Bus Passenger Seating and Crash Protection, 65509-65532 [07-5758]
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Federal Register / Vol. 72, No. 224 / Wednesday, November 21, 2007 / Proposed Rules
DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety
Administration
49 CFR Part 571
[Docket No. NHTSA–2007–0014]
RIN 2127–AK09
Federal Motor Vehicle Safety
Standards; Seating Systems, Occupant
Crash Protection, Seat Belt Assembly
Anchorages, School Bus Passenger
Seating and Crash Protection
National Highway Traffic
Safety Administration (NHTSA),
Department of Transportation (DOT).
ACTION: Notice of proposed rulemaking
(NPRM).
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AGENCY:
SUMMARY: NHTSA issued a report in
2002 on the results of a comprehensive
school bus research program examining
ways of further improving school bus
safety. Based on that research, we are
now proposing several upgrades to the
school bus passenger crash protection
requirements.
For new school buses of 4,536
kilograms (10,000 pounds) or less gross
vehicle weight rating (GVWR), we
propose to require lap/shoulder belts in
lieu of the lap belts that are currently
specified. For school buses with gross
vehicle weight ratings (GVWR) greater
than 4,536 kilograms (kg) (10,000
pounds), this NPRM provides guidance
to State and local jurisdictions on the
subject of installing seat belts. Each
State or local jurisdiction would
continue to decide whether to install
belts on these large school buses. Where
State or local decisions are made to
install lap or lap/shoulder belts on large
school buses, this NPRM proposes
performance requirements for those
voluntarily-installed seat belts on large
school buses manufactured after the
proposed effective date.
Other changes to school bus safety
requirements are also proposed,
including raising the height of seat
backs from 20 inches to 24 inches on all
new school buses.
DATES: Comments must be received on
or before January 22, 2008.
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
https://www.regulations.gov. Follow the
online instructions for submitting
comments.
• Mail: Docket Management Facility,
M–30, U.S. Department of
Transportation, West Building, Ground
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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: (202) 493–2251.
Regardless of how you submit your
comments, you should mention the
docket number of this document.
You may call the Docket at 202–366–
9324.
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 https://
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
non-legal issues, Mr. Charles Hott,
Office of Vehicle Safety Standards
(telephone: 202–366–0247) (fax: 202–
366–4921). Mr. Hott’s mailing address is
National Highway Traffic Safety
Administration, NVS–113, 1200 New
Jersey Avenue, SE., Washington, DC
20590.
For legal issues, Ms. Dorothy Nakama,
Office of the Chief Counsel (telephone:
202–366–2992) (fax: 202–366–3820).
Ms. Nakama’s mailing address is
National Highway Traffic Safety
Administration, NCC–112, 1200 New
Jersey Avenue, SE., Washington, DC
20590.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Introduction
II. Background
III. The Issue of Seat Belts on Large School
Buses
IV. Studies
V. Federal Guidance on Belts on Large Buses
a. NHTSA School Bus Research Results
b. Agency Recommended Best Practices
c. Guidance on Lap Belts on Large School
Buses
VI. Proposed Upgrades to Occupant Crash
Protection
a. Improving the Compartmentalized
School Bus Interior of Both Small and
Large School Buses
b. Additional Occupant Protection
Requirements for Small School Buses
(School Buses With a GVWR of 4,536 kg
(10,000 lb) or Less)
c. Additional Occupant Protection
Requirements for Large School Buses
With Voluntarily-Installed Lap/Shoulder
Seat Belts
d. Additional Requirements for Large
School Buses with Voluntarily-Installed
Lap Belts
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VII. Quasi-Static Test for Lap/Shoulder Belts
on Small and Large School Buses
a. Stage 1: Torso Belt Anchorage
Displacement
b. Stage 2: Energy Absorption Capability of
the Seat Back
c. Request for Comments
VIII. Lead Time
IX. Rulemaking Analyses and Notices
X. Public Participation
Appendix A to the Preamble—Proposed
Amendments to Federal Motor Vehicle
Safety Standards
I. Introduction
This document proposes to upgrade
the school bus occupant protection
requirements of the Federal motor
vehicle safety standards, primarily by
amendments to Federal Motor Vehicle
Safety Standard No. (FMVSS) No. 222,
‘‘School bus passenger seating and crash
protection’’ (49 CFR 571.222), and by
amendments to FMVSS Nos. 207, 208,
and 210. It also provides guidance to
state and local jurisdictions on the
subject of installing seat belts on large
school buses (school buses with a
GVWR greater than 4,536 kilograms (kg)
(10,000 pounds (lb)) and asks for
comments on the agency’s consideration
of ‘‘best practices’’ concerning the belts
on the large buses.1
This NPRM’s most significant
proposed changes to FMVSS No. 222
involve:
• Increasing the minimum seat back
height requirement from 20 inches from
the seat’s seating reference point (SgRP)
to 24 inches for all school buses;
• Requiring small school buses to
have a lap/shoulder belt at each
passenger seating position (the buses are
currently required to have lap belts);
• Incorporating test procedures into
the standard to test lap/shoulder belts in
small school buses and voluntarilyinstalled lap/shoulder belts in large
school buses to ensure both the strength
of the anchorages and the compatibility
of the seat with compartmentalization;
and,
• Requiring all school buses with seat
bottom cushions that are designed to
flip-up, typically for easy cleaning, to
have a self-latching mechanism.
1 ‘‘School bus’’ is defined in 49 CFR § 571.3 as a
bus that is sold, or introduced in interstate
commerce, for purposes that include carrying
students to and from school or related events, but
does not include a bus designed and sold for
operation as a common carrier in urban
transportation. A ‘‘bus’’ is a motor vehicle, except
a trailer, designed for carrying more than 10
persons. In this NPRM, when we refer to ‘‘large’’
school buses, we refer to those school buses with
GVWRs of more than 4,536 kg (10,000 lb). These
large school buses may transport as many as 90
students. ‘‘Small’’ school buses are school buses
with a GVWR of 4,536 kg (10,000 lb) or less.
Generally, these small school buses seat 15 persons
or fewer, or have one or two wheelchair seating
positions.
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The proposed guidance to state and
local jurisdictions on best practices of
installing seat belts on large school
buses acknowledges that, in terms of the
optimum passenger crash protection
that can be afforded an individual
passenger on a large school bus, a lap/
shoulder belt system, together with
compartmentalization, would afford that
optimum protection. Thus, we
encourage providers to consider lap/
shoulder belts on large school buses.
However, installing current lap/
shoulder belts on large school buses
would reduce the passenger carrying
capacity of large buses. If children were
diverted to other means of transport to
school, such as transport by smaller,
private vehicles, walking, or biking, the
belts on the buses could result in an
overall disbenefit to pupil
transportation safety due to the children
displaced from the large school buses
having to find less safe modes of
transportation to get to or from school
or related events. Thus, we are not
proposing to require lap/shoulder belts
on large school buses, and we
recommend providers to ascertain
whether installing lap/shoulder belts
would reduce the number of children
that are transported to school on large
school buses.
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II. Background
The Motor Vehicle and Schoolbus
Safety Amendments of 1974 directed
NHTSA to issue motor vehicle safety
standards applicable to school buses
and school bus equipment. In response
to this legislation, NHTSA revised
several of its safety standards to
improve existing requirements for
school buses, extended ones for other
vehicle classes to those buses, and
issued new safety standards exclusively
for school buses. FMVSS No. 222, one
of a set of new standards for school
buses, improves protection to school
bus passengers during crashes and
sudden driving maneuvers.
Effective since 1977, FMVSS No. 222
contains occupant protection
requirements for school bus seating
positions and restraining barriers. Its
requirements for school buses with
GVWR’s of 4,536 kg (10,000 lb) or less
differ from those set for school buses
with GVWR’s greater than 4,536 kg
(10,000 lb), because the ‘‘crash pulse’’ or
deceleration experienced by the small
school buses is more severe than that of
the large buses in similar collisions. For
the small school buses, the standard
includes requirements that all seating
positions must be equipped with
properly installed lap or lap/shoulder
seat belt assemblies and anchorages for
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passengers.2 NHTSA decided that seat
belts were necessary on small school
buses to provide adequate crash
protection for the occupants. For the
large school buses, FMVSS No. 222
relies on requirements for
‘‘compartmentalization’’ to provide
passenger crash protection.
Investigations of school bus crashes
prior to issuance of FMVSS No. 222
found the school bus seat was a
significant factor in causing injury.
NHTSA found that the seat failed the
passengers in three principal respects:
by being too weak, too low, and too
hostile (39 FR 27584; July 30, 1974). In
response to this finding, NHTSA
developed a set of requirements which
comprise the ‘‘compartmentalization’’
approach.
Compartmentalization ensures that
passengers are cushioned and contained
by the seats in the event of a school bus
crash by requiring school bus seats to be
positioned in a manner that provides a
compact, protected area surrounding
each seat. If a seat is not
compartmentalized by a seat back in
front of it, compartmentalization must
be provided by a padded and protective
restraining barrier. The seats and
restraining barriers must be strong
enough to maintain their integrity in a
crash yet flexible enough to be capable
of deflecting in a manner which absorbs
the energy of the occupant. They must
meet specified height requirements and
be constructed, by use of substantial
padding or other means, so that they
provide protection when they are
impacted by the head and legs of a
passenger. Compartmentalization
minimizes the hostility of the crash
environment and limits the range of
movement of an occupant. The
compartmentalization approach ensures
that high levels of crash protection are
provided to each passenger independent
of any action on the part of the
occupant.
III. The Issue of Seat Belts on Large
School Buses
NHTSA has considered the question
of whether seat belts should be required
on large school buses from the inception
of compartmentalization and the school
bus safety standards. NHTSA has been
repeatedly asked to require belts on
buses, and has repeatedly concluded
that compartmentalization provides a
high level of safety protection that
obviates the safety need for a Federal
requirement necessitating the
2 Lap/shoulder belts and appropriate anchorages
for the driver and front passenger (if provided)
seating position, lap belts and appropriate
anchorages for all other passenger seating positions.
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installation of seat belts. Further, the
agency has been acutely aware that a
decision on requiring seat belts in large
school buses cannot ignore the
implications of such a requirement on
pupil transportation costs. The agency
has been attentive to the fact that, as a
result of requiring belts on large school
buses, school bus purchasers would
have to buy belt-equipped vehicles
regardless of whether seat belts would
be appropriate for their needs. NHTSA
has concluded that those costs should
not be imposed on all purchasers of
school buses when large school buses
are currently very safe. In the area of
school transportation especially, where
a number of needs are competing for
limited funds, persons responsible for
school transportation might want to
consider other alternative investments
to improve their pupil transportation
programs which can be more effective at
reducing fatalities and injuries than seat
belts on large school buses, such as by
acquiring additional new school buses
to add to their fleet, or implementing
improved pupil pedestrian and driver
education programs. Since each of these
efforts competes for limited funds, the
agency has maintained that those
administrators should decide how their
funds should be allocated.
IV. Studies
Nonetheless, throughout the past 30
years that compartmentalization and the
school bus safety standards have been in
effect, the agency has openly and
continuously considered the merits of a
seat belt requirement for large school
buses.3 The issue has been closely
analyzed by other parties as well, such
as the National Transportation Safety
Board, and the National Academy of
Sciences. Various reports have been
issued, the most significant of which are
described below.
3 Through the years, NHTSA has been petitioned
about seat belts on large school buses. (See, e.g.,
denials of petitions to require seat belt anchorages,
41 FR 28506 (July 12, 1976), 48 FR 47032 (October
17, 1983); response to petition for rulemaking to
prohibit the installation of lap belts on large school
buses, 71 FR 40057 (July 14, 2006).) In a letter dated
February 16, 2007, the National Association of
Pupil Transportation (NAPT) petitioned the agency
‘‘to initiate rulemaking on occupant protection in
school buses.’’ NAPT said that it did not support
the installation of lap belts in large school buses,
nor the installation of lap/shoulder belts. NAPT
stated it ‘‘will only support changes to
compartmentalization when we are sure that those
changes will not compromise student safety in any
way.’’ NAPT requested that the agency review
FMVSS No. 222, ‘‘with the goal of establishing a
safety system that will definitively enhance the
current passenger crash protection for all children
that ride a school bus.’’ NAPT also advocated a
public education program emphasizing the
importance of safe school bus transportation.
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Studies
• National Transportation Safety
Board, 1987
In 1987, the National Transportation
Safety Board (NTSB) reported on a
study of forty-three post-standard school
bus crashes investigated by the Safety
Board. NTSB concluded that most
fatalities and injuries in school bus
crashes occurred because the occupant
seating positions were directly in line
with the crash forces, and that seat belts
would not have prevented those injuries
and fatalities. (NTSB/SS–87/01, Safety
Study, Crashworthiness of Large Poststandard School Buses, March 1987,
National Transportation Safety Board.)
• National Academy of Sciences,
1989
A 1989 National Academy of Sciences
(NAS) study concluded that the overall
potential benefits of requiring seat belts
on large school buses were insufficient
to justify a Federal mandate for
installation. The NAS also stated that
funds used to purchase and maintain
seat belts might be better spent on other
school bus safety programs with the
potential to save more lives and reduce
more injuries. (Special Report 222,
Improving School Bus Safety, National
Academy of Sciences, Transportation
Research Board, Washington, DC, 1989.)
• National Transportation Safety
Board, 1999
In 1999, NTSB reported on six school
bus crashes it investigated in which
passenger fatalities or serious injuries
occurred away from the area of vehicle
impact. NTSB found
compartmentalization to be an effective
means of protecting passengers in
school bus crashes. However, because
many of those passengers injured in the
six crashes were believed to have been
thrown from their compartments, NTSB
believed other means of occupant
protection should be examined. (NTSB/
SIR–99/04, Highway Safety Report, Bus
Crashworthiness Issues, September
1999, National Transportation Safety
Board.)
• National Academy of Science, 2002
In 2002, NAS published a study that
analyzed the safety of various
transportation modes used by school
children to get to and from school and
school-related activities. The report
concluded that each year there are
approximately 815 school transportation
fatal injuries per year. Two percent were
school bus-related, compared to 22
percent due to walking/bicycling, and
75 percent from passenger car crashes,
especially those with teen drivers. The
report stated that changes in any one
characteristic of school travel can lead
to dramatic changes in the overall risk
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to the student population. Thus, NAS
concluded, it is important for school
transportation decisions to take into
account all potential aspects of changes
to requirements to school
transportation. (Special Report 269,
‘‘The Relative Risks of School Travel: A
National Perspective and Guidance for
Local Community Risk Assessment,’’
Transportation Research Board of the
National Academies, 2002.)
• National Highway Traffic Safety
Administration, 2002
In 2002, NHTSA issued a
Congressional Report that detailed
occupant safety on school buses and
analyzed options for improving
occupant safety. NHTSA concluded that
compartmentalization effectively
lowered injury measures by distributing
crash forces with the padded seating
surface. Lap belts showed little to no
benefit in reducing serious/fatal
injuries. The agency determined that
properly used combination lap and
shoulder belts have the potential to be
effective in reducing fatalities and
injuries for not only frontal collisions,
but also rollover crashes where belt
systems are particularly effective in
reducing ejection. However, the
addition of lap/shoulder belts on buses
would increase capital costs and reduce
seating capacity on the buses. (‘‘Report
to Congress, School Bus Safety:
Crashworthiness Research, April 2002,’’
https://www-nrd.nhtsa.dot.gov/
departments/nrd-11/SchoolBus/
SBReportFINAL.pdf.)
V. Federal Guidance on Belts on Large
Buses
This document provides guidance to
state and local jurisdictions on the
subject of installing seat belts on large
school buses and asks for comments on
the agency’s consideration of ‘‘best
practices’’ concerning the belts on the
large buses.
This guidance is provided in response
to the information that the agency
received at its July 11, 2007 public
meeting in Washington, DC on seat belts
on school buses (notice of public
meeting, 72 FR 30739, June 4, 2007,
Docket 28103).4 In this meeting, NHTSA
brought together a roundtable of State
and local government policymakers,
school bus and seat manufacturers,
pupil transportation associations, and
consumer groups to address: State and
local policy perspectives regarding
whether to require seat belts on school
buses; information on the type of seat
4 NHTSA also received written comments to
docket 28103. We will address all relevant issues
raised in those comments in today’s NPRM and in
a final rule or other rulemaking document following
today’s NPRM.
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belt system designs that are currently
being offered on large school buses; the
economic impact that implementation
of seat belt requirements for school
buses (including purchase and
maintenance of belts) have on States
and local school districts; and the
experience of schools and States in
training and educating children, parents
and drivers to use seat belts on large
school buses.5 At the meeting,
participants requested that NHTSA
provide up-to-date Federal guidance on
whether seat belts should be provided
on school buses, and whether lap belts
should or should not be installed.
The agency has considered all of the
comments made at the meeting. NHTSA
found the following views particularly
helpful:
• Mr. Charles Hood of the Florida
Department of Education related the
State of Florida’s experience with lap
belts on school buses. Informally, Mr.
Hood estimated that the lap belt usage
rate in Florida was about 70 percent for
elementary school students, 35 percent
for middle school students, and 25
percent for high school students. Mr.
Hood reported that vandalism and
maintenance of the seat belts were not
major concerns. Mr. Hood estimated
that the annual charge to equip all of
Florida’s 1399 school buses with lap/
shoulder belts would be about $14
million.
• Mr. Hood believed that the key
point of the debate is whether the three
point belts will: Improve overall safety
through the crash protection
improvements that they provide, or
reduce overall safety by potentially
reducing the number of children who
ride in school buses. Mr. Hood stated
that States that require lap belts need
Federal guidance as to whether they
may or should continue to specify lap
belts in their school buses.
• Ms. Ann Roy Moore of the
Huntsville, Alabama City Schools
recommended that national agencies
come up with some standards that could
be used to address the issue of school
bus safety generally and seat belt safety
in particular.
• Mr. Ken Hedgecock of Thomas Built
Buses stated that two-point belts are on
27 percent of the school buses Thomas
Built manufactures, and three-point
belts are on 2 percent the school buses
that it manufactures. Mr. Hedgecock
said that the greatest concern relating to
seat belts pertains to capacity and cost
issues of the three-point belt system.
The reduction in capacity and
incremental costs of the three-point
5 A transcript of the July 11, 2007 public meeting
is available in docket 28103.
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system may have the unintended
consequence of transporting fewer
children on the yellow school bus, thus
negatively affecting the safety of our
nation’s children. Mr. Hedgecock
recommended the following as it
pertains to seat belts: Clarification is
needed on the use of two-point belt
systems versus three-point belt systems
in school buses; clarification is needed
on the designated seating position as it
pertains to a seat with seat belts; and
there is a need for clear performance
standards for the integration of all
systems: the school bus, the seat, and
the belts.
• Mr. Steve Wallen of Safeguard, a
division of Indiana Mills Manufacturing
Inc. (IMMI), stated that its testing shows
that compartmentalization does well in
front and rear impact crashes, but not
particularly well in rollovers. Mr.
Wallen recommends the FMVSSs
should be amended so as to allow for
lap/shoulder belts while maintaining
compartmentalization to protect
unbelted occupants. Mr. Wallen
suggested that the FMVSSs specify
requirements such that a school bus seat
can withstand a crash with a student
wearing a seat belt and one behind not
wearing a seat belt at the same time. Mr.
Wallen noted that retrofitting school
buses is substantially more expensive
and difficult than installing seats in new
buses.
• Ms. Robin Leeds of the National
School Transportation Association
(NSTA) stated that a Federal mandate is
not appropriate because of the costs.
NSTA believes States and local school
districts are in a better position to
determine the best use of their resources
than the Federal government. In the
NSTA’s view, the only way any safety
belt program can be successful is if it
has the full commitment of the school
administration and of parents to make
them work. NSTA also recommended
that NHTSA develop standards for
voluntarily-installed lap/shoulder belt
systems so that ‘‘everybody knows what
system to use when they do install those
systems.’’
a. NHTSA School Bus Research Results
Our guidance about seat belts on
school buses also takes into account the
agency’s research findings assessing the
efficacy of existing safety measures
employed on school buses and possible
improvements to school bus occupant
protection.
The Transportation Equity Act for the
21st Century (TEA–21) directed NHTSA
to study and assess school bus occupant
safety and analyze options for
improvement. In response, the agency
developed a research program to
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determine the real-world effectiveness
of FMVSS No. 222 requirements for
school bus passenger crash protection,
evaluate alternative passenger crash
protection systems in controlled
laboratory tests, and provide findings to
support rulemaking activities to upgrade
the passenger crash protection for
school bus passengers.
The research program consisted of
NHTSA first conducting a full-scale
school bus crash test to determine a
representative crash pulse. The crash
test was conducted by frontally
impacting a conventional style school
bus (Type C) into a rigid barrier at 30
mph (48.3 km/h). The impact speed was
chosen to ensure that sufficient energy
would be imparted to the occupants in
order to evaluate the protective
capability of compartmentalization, plus
provide a level at which other methods
for occupant injury mitigation could be
evaluated during sled testing. A 30 mph
(48 km/h) impact into the rigid barrier
is also equivalent to two vehicles of
similar size impacting at a closing speed
of approximately 60 mph (96 km/h),
which was found to be prevalent in the
crash database files.
In the crash test, we used Hybrid III
50th percentile adult male dummies
(representing adult and large teenage
occupants), 5th percentile adult female
(representing an average 12-year-old
(12YO) occupant), and a 6-year-old
child dummy (representing an average
6-year-old (6YO) occupant). The
dummies were seated so that they were
as upright as possible and as rearmost
on the seat cushion as possible. The
agency evaluated the risk of head injury
recorded by the dummies (Head Injury
Criterion (HIC15)), as well as the risk of
chest (chest G’s) and neck injury (Nij),6
as specified in FMVSS No. 208
‘‘Occupant crash protection.’’
NHTSA then ran frontal crash test
simulations at the agency’s Vehicle
Research and Test Center (VRTC), using
6 HIC15, Chest G, and Nij values are used to
predict injury risk in frontal crashes. HIC15 is a
measure of the risk of head injury, Chest G is a
measure of chest injury risk, and Nij is a measure
of neck injury risk. The reference values for these
measurements are the thresholds for compliance
used to assess new motor vehicles with regard to
frontal occupant protection during crash tests,
FMVSS No. 208. For HIC15, a score of 700 is
equivalent to a 30 percent risk of a serious head
injury (skull fracture and concussion onset). In a
similar fashion, Chest G of 60 equates to a 20
percent risk of a serious chest injury and Nij of 1
equates to a 22 percent risk of a serious neck injury.
For all these measurements, higher scores indicate
a higher likelihood of risk. For example, a Nij of 2
equates to a 67 percent risk of serious neck injury
while a Nij of 4 equates to a 99 percent risk. More
information regarding these injury measures can be
found at NHTSA’s Web site (https://wwwnrd.nhtsa.dot.gov/pdf/nrd-11/airbags/
rev_criteria.pdf).
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a test sled to evaluate passenger
protection systems. Twenty-five sled
tests using 96 test dummies of various
sizes utilizing different restraint
strategies were conducted that
replicated the acceleration time history
of the school bus full-scale frontal
impact test. The goal of the laboratory
tests was to analyze the dummy injury
measures to gain a better understanding
of the effectiveness of the occupant
crash protection countermeasures. In
addition to injury measures, dummy
kinematics and interaction with
restraints (i.e., seat backs and seat belts,
as well as each other) were also
analyzed to provide a fuller picture of
the important factors contributing to the
type, mechanism, and potential severity
of any resulting injury.
NHTSA studied three different
restraint strategies: (a)
compartmentalization; (b) lap belt (with
compartmentalization); and, (c) fore/aft
loading.7
Within the context of these restraint
strategies, various boundary conditions
were evaluated: (a) Seat spacing—483
mm (19 inches), 559 mm (22 inches)
and 610 mm (24 inches); (b) seat back
height—nominally 508 mm (20 inches)
and 610 mm (24 inches); and, (c) fore/
aft seat occupant loading. Ten dummies
were tested with misused or out-ofposition (OOP) lap or shoulder
restraints. The restraints were misused
by placing the lap belt too high up on
the waist, placing the lap/shoulder belt
placed behind the dummy’s back, or
placing the lap/shoulder belt under the
dummy’s arm.
The agency found the following with
regard to compartmentalization:
• Low head injury values were
observed for all dummy sizes, except
when override 8 occurred.
• High head injury values or dummyto-dummy contacts beyond the
biofidelic range of the test dummy were
produced when the large male dummy
overrode the seat in front of it, while the
high-back seats prevented this.
• Low chest injury values were
observed for all dummy sizes.
• Based on dummy motion and
interaction with each other,
compartmentalization was sensitive to
seat back height for the 50th percentile
male dummy.
• Compartmentalization of 6YO and
5th percentile female dummies did not
7 Unbelted occupants in the aft seat will affect the
kinematics of belted occupants in the fore seat due
to seat back deformation. Similarly, belted occupant
loading of the fore seat back thru the torso belt will
affect the compartmentalization for unbelted
occupants in the aft seat.
8 Override means an occupant’s head or torso
translates forward beyond the forward seat back
providing compartmentalization.
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appear to be sensitive to rear loading
conditions.
• Compartmentalization of the 50th
percentile male dummy did not appear
to be sensitive to seat spacing for the
50th percentile male dummy.
The agency found the following with
regard to lap belts on large school buses:
• Head and chest injury values were
low for all dummy sizes.
• The average neck injury value was
above the injury assessment reference
value (IARV) for all test dummies, and
was 70 percent above for the 5th
percentile female dummy.
• Neck injury values increased for the
5th percentile female dummy when the
seat spacing was increased from 483
mm (19 inches) to 559 mm (22 inches).
The agency found the following with
regard to properly worn lap/shoulder
belts on school buses:
• Head, chest and neck injury values
were low for all size dummies and
below those seen in the
compartmentalization and lap belt
results.
• Average head injury values were, at
most, about half those seen in the
compartmentalization and lap belt
results.
• Neck injury values increased with
application of rear loading for the 6YO
and 5th percentile female dummies.
• Lap/shoulder belt systems would
require approximately 15 inches seat
width per passenger seating position.
The standard school bus bench seat is
39 inches wide, and is considered a
three-passenger seat. If the width of the
seat bench were increased to 45 inches
for both seats on the left and right side
of the school bus, the aisle width would
be reduced to an unacceptable level.
NHTSA found that, for improperly
worn lap/shoulder belts:
• Placing the shoulder belt behind the
dummy’s back resulted in dummy
motion and average dummy injury
values similar to lap belt restraint.
• Placing the shoulder belt under the
dummy’s arm provided more restraint
on dummy torso motions than when the
belt is placed behind the back. Average
dummy injury values for the 6YO were
about the same as seen with lap/
shoulder belts and 5th percentile female
dummy injury values were between
those seen in lap/shoulder belts and lap
belts.
b. Agency Recommended Best Practices
School buses are one of the safest
forms of transportation in the U.S. Every
year, approximately 474,000 public
school buses, transporting 25.1 million
children to and from school and school-
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related activities,9 travel an estimated
4.8 billion route miles.10 Over the 11
years ending in 2005, there was an
annual average of 26 school
transportation related fatalities (11
school bus occupants (including drivers
and passengers) and 15 pedestrians).11
The bus occupant fatalities were
comprised of six school-age children,
with the remaining being adult drivers
and passengers.12 On average, there
were 9 crashes per year in which an
occupant was killed. The school bus
occupant fatality rate of 0.23 fatalities
per 100 million vehicle miles traveled
(VMT) is more than six times lower than
the overall rate for motor vehicles of 1.5
per 100 million VMT.13
The agency’s school bus research
results indicated that lap/shoulder belts
could enhance the safety of large school
buses, such that a child who has a seat
on the school bus and who is belted
with a lap/shoulder belt on the bus
would have an even lower risk of head
and neck injury than on current large
school buses.14 Thus, if ample funds
were available for pupil transportation,
and pupil transportation providers
could order and purchase a sufficient
number of school buses needed to
provide school bus transportation to all
children, we would recommend that
pupil transportation providers consider
installing lap/shoulder belts on large
school buses because of the
enhancements that lap/shoulder belts
could make to school buses.
Realistically, however, we recognize
that funds provided for pupil
transportation are limited, and that the
monies spent on lap/shoulder belts on
large school buses would usually draw
from the monies spent on other crucial
aspects of school transportation, such as
purchasing new school buses to ensure
that as many children as possible are
provided school bus transportation, on
9 School Transportation News, Buyers Guide
2007.
10 This value was reported by School Bus Fleet
2007 Fact Book.
11 ‘‘Traffic Safety Facts—School Transportation
Related Crashes,’’ NHTSA, DOT HS 810 626. The
data in this publication account for all school
transportation-related deaths in transporting
students to and from school and school related
activities. This includes non-school buses used for
this purpose when these vehicles are involved in
a fatal crash.
12 For the crashes resulting in the 11 annual
school bus occupant fatalities, 51 percent of the
fatalities and 52 percent of the crashes were from
frontal collisions. Traffic Safety Facts 2005, School
Transportation-Related Crashes, DOT HS 810 626.
13 Traffic Safety Facts 2005, DOT HS 810 631.
14 The TEA–21 research program did not study
whether belts could enhance the protection of
compartmentalization in side crashes and rollovers.
Most school bus fatalities occur in a crash involving
a rollover, and the side crash fatalities are about as
frequent as front crash fatalities.
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driver and pupil training on safe
transportation practices, and on upkeep
and maintenance of school buses and
school bus equipment. Bearing these
considerations in mind, we recommend
that pupil transportation providers
consider lap/shoulder belts on large
school buses only if there would be no
reduction in the number of children that
are transported to or from school or
related events on large school buses.
Reducing bus ridership would likely
result in more student fatalities, since
walking and private vehicles are less
safe than riding a large school bus
without seat belts.
Our best practices recommendation
seeks to reflect real world
considerations about the safety record of
school buses, the economic impact on
school systems incurred by the costs of
seat belts and the impact that lap/
shoulder belts have on the seating
capacity of large school buses. Our
laboratory test results indicate that our
test dummies measured better head
protection performance when lap/
shoulder belts were properly used with
compartmentalization than compared to
compartmentalization alone. However,
best practices compel us to acknowledge
that installation of lap/shoulder belts, as
currently designed, reduce the number
of seats offered to students, resulting in
fewer children riding school buses,
exposing more children to higher safety
risks in alternative forms of transport to
or from school or related events, and a
probable overall net safety disbenefit
due to their installation.
Best practices compel us to encourage
pupil transportation providers to make
a comprehensive analysis of their needs
and determine how lap/shoulder belts
on large school buses accord with those
needs. The best practices approach we
have developed allows States the
leeway to decide whether to require seat
belts on large school buses, and whether
lap only or lap/shoulder belts should be
ordered. Given the tradeoff noted above,
States should be permitted the
flexibility of deciding whether to order
large school buses with the seat belt
safety enhancements after considering
the excellent safety record of large
school buses with
compartmentalization, the benefits of
allocating resources to belts as opposed
to alternative safety measures, and the
means available to ensure that the belts
would be used. If a State were to
determine that lap/shoulder belts are in
its best interest, NHTSA encourages the
State to install those systems. Today’s
document proposes performance
requirements for the lap/shoulder belts,
to ensure they will work well in a crash
even if voluntarily installed.
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Certain highway safety grant funds
may continue to be used to fund the
purchase and installation of seat belts
(lap or lap/shoulder) on school buses.
Annually, all States, the District of
Columbia, Puerto Rico, the Bureau of
Indian Affairs, and the U.S. territories
receive NHTSA Section 402 State and
Community Highway Safety Formula
Grant Funds. A wide range of behavioral
highway safety activities that help
reduce crashes, deaths, and injuries,
including seat belt-related activities,
qualify as eligible costs under the
Section 402 program. Each State
determines how to allocate its funds
based on its own priorities and
identified highway safety problems as
described in an annual Highway Safety
Plan (HSP).
As with all proposed expenditures of
Section 402 funds, the purchase and
installation of seat belts on school buses
must be identified as a need in the
State’s HSP and comply with all
requirements under 23 U.S.C. Part 1200.
Section 402 funds may not be used to
purchase the school bus in its entirety,
but may fund only the incremental
portion of the bus cost directly related
to the purchase and installation of seat
belts.
We would advise States that are
considering purchasing seat belts for
school buses to be guided by the
proposed standards in this notice of
proposed rulemaking.
c. Guidance on Lap Belts on Large
School Buses
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In the July 11, 2007 public meeting,
some participants asked for guidance on
whether lap belts should be prohibited
on large school buses. The question was
asked in the aftermath of school bus
research studies that found lap belts
were associated with increased risk of
injury on large school buses.15
15 See the results of NHTSA’s school bus research
program (Report to Congress, School Bus Safety:
Crashworthiness Research, supra). In addition, a
1985 study by Transport Canada provided data
comparing the reaction of three belted and three
unbelted 5th percentile adult female
anthropomorphic test dummies in a 48 km/h (30
mph) frontal collision of a large school bus meeting
compartmentalization requirements. The results
indicated that the belted dummies experienced
higher head accelerations, lower chest accelerations
and more severe neck extension than did the
unbelted ones. Accordingly, the study concluded
that the use of a lap belt system in a school bus
‘‘may result in more severe head and neck injuries
for a belted occupant than an unbelted one, in a
severe frontal collision.’’ (School Bus Safety Study,
January 1985). After analyzing the Transport
Canada study, NHTSA could not conclude from the
report’s findings that belts degraded the benefits of
compartmentalization to the extent that the
supplemental restraint system rendered inoperative
the safety of large school buses, but NHTSA
acknowledged that the possibility exists that the
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After considering the data and other
information on lap belts on large school
buses, NHTSA does not believe there is
a need to prohibit lap belts on the buses.
In its 1999 report on bus
crashworthiness, the NTSB concluded
that the compartmentalization
requirement for school buses in FMVSS
No. 222 is incomplete in addressing
school bus occupant protection in
rollovers and lateral impacts from large
vehicles, in that in such crashes,
passengers do not always remain
completely within the seating
compartment. Although we have not
found a safety need exists with respect
to those non-frontal crashes to warrant
requiring seat belts on large school
buses,16 we have always permitted
States to choose to require the belts over
and above the Federally required
compartmentalization in the school
buses they purchase.
We realize that laboratory research,
including our own on lap belted
dummies, shows relatively poor
performance of lap belts in large school
buses. However, this research involved
severe frontal impacts. We cannot make
a determination, based on the results of
the limited testing with lap belt
restraints in a severe frontal crash
condition, that the addition of lap belts
in large school buses reduces overall
occupant protection. Lap belts are
required in three States (New York
(1987), New Jersey (1994), Florida
(2001)), in many other school districts,
and in special-needs equipped school
buses. NHTSA has examined in depth
New York State school bus crash data
for lap belt equipped and non-belt
equipped buses, and could not conclude
that lap belts either helped or hurt
occupant injury outcomes.
VI. Proposed Upgrades to Occupant
Crash Protection
After considering the findings of
NHTSA’s school bus research program,
we have decided to issue this NPRM to
propose several sets of upgrades to the
school bus safety requirements. The first
set of upgrades involves improving the
compartmentalized school bus interior
on both small and large school buses.
Seat back height would be increased
from 20 inches to 24 inches to reduce
the potential for passenger override in a
crash, and school buses with seat
occupant kinematics shown in the Canadian tests
could occur. (Docket No. 85–14; Notice 02, RIN
2127–AB84, March 22, 1989).
16 We reiterate our conclusion that the overall
potential benefits of requiring lap belts on large
school buses are insufficient to justify a Federal
requirement for mandatory installation. NAS has
also suggested that the funds used for required seat
belts might be better used in other school bus safety
programs. Special Report 222 (1989), supra.
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bottom cushions that are designed to
flip-up, typically for easy cleaning,
would need a self-latching mechanism.
The proposal to raise seat back height
responds to findings from the agency’s
school bus research program, while the
proposal for self-latching mechanisms
responds to an NTSB recommendation
to NHTSA (H–84–75).
The second set of upgrades involves
specifics about the occupant protection
requirements required for passengers of
small school buses (school buses with a
GVWR of 10,000 lb or less). In response
to NHTSA’s school bus research
findings, this NPRM proposes to require
small school buses to have lap/shoulder
belts instead of just lap belts. The lap/
shoulder belts would have to fit all
passengers ages 6 through adult, and be
equipped with retractors. The lap/
shoulder belts would have to meet the
existing anchorage strength
requirements for lap/shoulder belts in
FMVSS No. 210 and would be subject
to new requirements for belt anchor
location and torso belt adjustability.
FMVSS No. 207 would also be amended
to apply to passenger seats in small
school buses. A newly-developed
‘‘quasi-static’’ test requirement
(discussed in the next section of this
preamble) would be adopted into
FMVSS No. 222 to test school bus seats
with lap/shoulder belts, to help ensure
that seat backs incorporating lap/
shoulder belts are strong enough to
withstand the forward pull of the torso
belts in a crash and the forces imposed
on the seat from unbelted passengers to
the rear of the belted occupants. These
requirements would add to existing
compartmentalization requirements for
seat performance (e.g., seat performance
forward, S5.1.3 of FMVSS No. 222, and
seat performance rearward, S5.1.4). A
minimum seat belt width of 15 inches
would be specified for all school bus
seats with lap/shoulder belts.
The third set of upgrades involves
requirements for voluntarily-installed
seat belts on large school buses. For
large school buses with voluntarilyinstalled lap/shoulder belts, the vehicle
would be subject to the requirements
described above for lap/shoulder belts
on small school buses, except FMVSS
No. 207 would not apply to the
passenger seats. The quasi-static test
procedures for small school buses
would slightly vary from those applying
to seats on large school buses with
voluntary lap/shoulder belts, to account
for crash characteristic differences of
large school buses versus small school
buses. (Due to the mass and other
characteristics of the vehicles, in
crashes small school buses are subject to
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higher severity forces than large school
buses.)
For large school buses with
voluntarily-installed lap belts, the
vehicles would be required to meet
FMVSS No. 210 requirements of a
loading force of 22,240 N (5,000
pounds) per seating position. This
would be consistent with the existing
lap belt loading requirement for small
school buses and light vehicles with lap
belt only systems.
These proposed requirements are
discussed below.17 In addition, NHTSA
has prepared a Technical Analysis that,
among other things, presents a detailed
analysis of data, engineering studies,
and other information supporting these
proposals.18 A copy of this Technical
Analysis will be placed in the docket.
a. Improving the Compartmentalized
School Bus Interior of Both Small and
Large School Buses
• Seat back height. At present, school
bus seat back height is specified at
S5.1.2 of FMVSS No. 222 to be at a
minimum 508 millimeters (mm) (20
inches (in)). In this NPRM, we propose
that the minimum seat back height for
school bus seats be raised to 610 mm (24
in).
In NHTSA’s school bus research
program, when dummies representing
older students were compartmentalized
with current 20-inch high seat backs,
the dummies were much more likely to
override the seat and make head contact
with test dummies that were placed in
seats forward of the dummies. While the
injury potential of these contacts was
not quantifiable, dummies overriding
seats means that the
compartmentalization was not working.
The highest HIC 15 value was registered
when a 50th percentile male dummy
behind a 20-inch seat back contacted the
seat back two rows ahead. In cases
where incidental contact did occur, the
HIC 15 values tended to be very high.
In two cases, the HIC 15 values were
over 2,000 and the third was over 5,000.
For the 24-inch seat backs, there was
only dummy interaction between the
rows of seats if both the forward and
rearward dummies were 50th percentile
male dummies. The high seat back seats
effectively prevented the passengers
from overriding the seat backs.
In the past, NHTSA has been
informed that with the higher seat
backs, drivers are not able to see and
supervise the children. However,
17 In Appendix A to this preamble, we list the
FMVSSs affected by this NPRM and the proposed
amendments to those standards.
18 NHTSA Technical Analysis to Support
Upgrading the Passenger Crash Protection in School
Buses (September 2007).
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NHTSA is not aware of data showing
that the higher seat backs result in
supervision problems. NHTSA notes
that four states (Illinois, New Jersey,
New York, and Ohio) plus many other
school districts require their school bus
seats to have 24-inch seat backs. These
states represent about 20 percent of all
students in public transportation. We
have received no reports of supervisory
or safety related issues resulting from
the higher seat backs from these
jurisdictions. We request public
comment on this issue.
• Restraining barrier height. We
propose to amend S5.2.2, ‘‘Barrier
position and rear surface area,’’ to
specify that the rear surface area of the
restraining barrier shall be such that in
the front projected view, the restraining
barrier’s surface area above the
horizontal plane that passes through the
seating reference point, and below the
horizontal plane 610 mm (24 inches)
above the seating reference point, shall
be not less than 90 percent of the seat
bench width in millimeters multiplied
by 610 (inches multiplied by 24). We are
also proposing that restraining barriers
have a minimum width of 75 percent of
the seat bottom cushion at the upper
portion of the restraining barrier. This is
needed to ensure that the restraining
barrier has sufficient width and area so
that it sufficiently restrains passengers.
Further, we seek to clarify that the
restraining barrier’s perimeter need not
coincide with or lie outside of the
perimeter of the seat back of the seat for
which it is required if that seat back is
higher than the minimum required by
FMVSS No. 222. (Such a position would
be consistent with an April 8, 1977
NHTSA interpretation letter to Wayne
Corporation.)
• Seat cushion latches. At present,
FMVSS No. 222 at S5.1.5 requires seat
bottom cushions to withstand an
upward force that is five times the
weight of the seat bottom cushion.
S5.1.5 specifies that, with all manual
attachment devices between the seat
and the seat cushion in the
manufacturer’s designated position for
attachment, the seat cushion shall not
separate from the seat at any attachment
point when subjected to an upward
force in Newtons of 5 times the mass of
the seat cushion in kilograms and
multiplied by 9.8 m/s2, applied in any
period of not less than 1 nor more than
5 seconds, and maintained for 5
seconds.
This text of S5.1.5 has remained
unchanged since 1976. NHTSA notes
that in order to allow the cushion to be
removed or flipped up for maintenance,
some seat cushions have been designed
to attach to the rear seat frames with
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clips that swivel on and off the frame
and with stationary clips that slip under
the front frame member. Such cushion
designs meet S5.1.5.
In 1984, the National Transportation
Safety Board (NTSB) issued a
recommendation to NHTSA (H–84–75)
that seat cushions be attached with a
fail-safe latching device to ensure that
the cushions remain in their installed
position during impacts and rollovers.
This recommendation was closed based
on a 1987 survey of NHTSA school bus
manufacturers which indicated that the
manufacturers would voluntarily
implement the NTSB recommendation.
Data indicate, however, that the school
bus manufacturers did not voluntarily
implement the NTSB recommendation.
NTSB believes there was a safety need
for a requirement for a latching device
because a 1987 NTSB study reported
that seat cushions came loose in 16 of
44 school bus crashes. In four of the 16
crashes, all of the seat cushions came
loose, and minor injuries were caused
by the loose seat cushions in three of the
16 crashes. The NTSB concluded that
seat cushions came free because clips
were not secured to the seat frame or
were loose and free to rotate. The 1987
report indicated the following safety
concerns associated with loose
cushions: Flying cushions can strike
and injure occupants; occupants can fall
through the opening left by the cushion;
loose cushions may block exit routes;
and loose cushions may hide injured
occupants.
In the agency’s school bus research
program, seat cushions became
detached in the frontal crash of a large
school bus. To address the safety
concerns raised by the NTSB, NHTSA is
proposing to amend S5.1.5 to require
latching devices for school bus seats
that have latches that allow them to flip
up or be removed for easy cleaning. We
also propose a test procedure that would
require the latch to activate after a 22 kg
(48 lb) mass is placed on top of the seat
at the seat cushion’s center. The 48 lb
weight is that of an average 6-year-old
child. The test would ensure that any
unlatched seat cushion would latch
when a child occupant sits on the seat.
b. Additional Occupant Protection
Requirements for Small School Buses
(School Buses With a GVWR of 4,536 kg
(10,000 lb) or Less)
• The agency proposes that small
school buses be required to have lap/
shoulder belts at all passenger seating
positions. Since the FMVSSs were first
promulgated, small school buses
passenger seats have been required to
have passenger lap belts (defined as
Type 1 belts in FMVSS No. 209) as
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specified in FMVSS No. 208, that meet
the lap belt strength requirements
specified in FMVSS No. 210. Lap belts
were required because the ratio of the
mass of a potential collision partner to
that of a small school bus is larger than
for a large school bus. Thus, for vehicleto-vehicle collisions, the deceleration of
a small school bus will be greater than
for a large school bus. However, before
today, we have never sought to require
lap/shoulder belts for all passenger seats
in small school buses.19
The primary reason for proposing lap/
shoulder belts is the increased level of
protection that children riding in a
small school bus gain by having a lap/
shoulder belt. Lap/shoulder belts
provide an increased level of protection
from lap belts by reducing the potential
of head and neck injuries in frontal
impacts. The relatively poor
performance of lap belted dummies in
NHTSA’s frontal sled test research is of
greater concern for small school buses.
Frontal crashes will tend to be more
severe for these smaller school buses
than for large school buses. Properly
worn lap/shoulder belts will reduce the
potential negative effects of lap belts in
severe frontal crashes while maintaining
and potentially enhancing the
protection offered in other crash modes.
In NHTSA’s 2002 Report to Congress,
School Bus Safety: Crashworthiness
Research, NHTSA noted that the results
of the electronic data and video data
showed that the dummies restrained
with lap and shoulder belts had a lower
risk of head and neck injuries than
unbelted dummies.
Finally, while installation in large
school buses could result in a 17
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19 FMVSS No. 208 (S4.4.5) requires buses, other
than school buses, with a GVWR of 10,000 lb or less
manufactured on or after September 1, 2007 to have
lap/shoulder belts (Type 2 belts) at all passenger
seating positions other than side-facing positions.
Today’s NPRM would be consistent with that
requirement for the non-school buses. (We note that
the heading of S4.4.5 of FMVSS No. 208 should
specify that the section does not apply to small
school buses. See https://dmses.dot.gov/docimages/
pdf89/293807_web.pdf, NHTSA letter February 19,
2004, explaining the typographical error. Today’s
NPRM would correct the typographical error in
S4.4.5.)
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percent reduction in seating capacity,
small school buses are already
configured with seating positions that
can accommodate lap/shoulder belts
without a reduction in seating
capacity.20
• Adjustability of the belt system.
NHTSA proposes that requirements be
added to FMVSS No. 210 that would
ensure that the seat belt anchorages on
school bus seats are designed so that the
belt system will properly fit the range of
children on a school bus: The average 6year-old (represented by the Hybrid III
6-year-old child dummy (45 inches tall/
52 pounds)); the average 12-year-old
(represented by the Hybrid III 5th
percentile female dummy (59 inches/
108 pounds)) and; the large high school
student (represented by the 50th
percentile adult male dummy (69
inches/172 pounds)). Proper fit for
children prevents injury and would
ensure that the system performs
properly in a crash. In addition, if the
lap/shoulder seat belts did not fit the
child occupant properly, there is an
increased likelihood that the child
would misuse the lap/shoulder belt
system by placing the shoulder portion
under the arm or behind the back.
NHTSA’s school bus research results
showed that when the shoulder belt was
placed behind the back, the restraint
system functioned like a lap belt. Lap
belts produced a higher risk of neck
injury in the testing program.
In the agency’s school bus research
program, we saw examples of improper
seat anchorage location. The first set of
lap/shoulder belt seats supplied for
testing in the school bus research
program did not have the anchorages of
the lap/shoulder belts located so that
the seat belts would fit appropriately on
any of the test dummies. The torso belt
came across the dummies’ heads and
necks and the lap belt was high on the
abdomen instead of on the hips. After
20 The typical seating configuration of small
school buses is based on five rows of 762 mm (30
inches) two passenger seats. Therefore, the
installation of lap/shoulder belts into each seating
position should not result in a reduction in
capacity.
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consultation with the seat manufacturer,
a second set of lap/shoulder belt
equipped seats had seat belt anchorages
such that the seat belts fit all of the test
dummies (6-year-old to 50th percentile
male) properly. The torso belt anchorage
was higher on the seat back to allow for
proper placement of the torso belt on
taller people.21 Also, as in the
previously supplied seats, the shoulder
belt had an adjustable anchorage that
slides up and down a second shoulder
belt so it could properly adjust for the
sitting height of the typical 6-year-old
through the adult size passenger.
NHTSA has tentatively determined
that design requirements for the seat
belt anchorages should be specified
such that the belts would be sure to fit
occupants ranging in size from the
average 6-year-old child to the average
adult male. The anchorage locations
were determined by placing test
dummies (6-year-old, 5th percentile
female and 50th percentile male) into
the school bus seats. The results are
reported in NHTSA’s Vehicle Research
Test Center (VRTC) Test Report, Test
Methodology for Lap/Shoulder Belts in
School Buses. NHTSA has tentatively
decided to apply the location
requirements of FMVSS No. 210, S4.3.1.
See Figure 1 of this preamble, below.
In addition, for the reasons discussed
in the agency’s technical report
supporting this NPRM, we propose that
school bus seats with lap/shoulder belts
have a minimum shoulder belt
adjustment range between 280 mm (11
inches) above the seating reference
point and the school bus torso belt
anchor point, to ensure that the
shoulder belt will fit passengers ranging
in size from a 6-year-old child to a 50th
percentile adult male.
BILLING CODE 4910–59–P
21 A torso belt anchorage located below the adult
dummy’s shoulder may increase the spinal
compression loading in a crash, would increase the
risk of the dummy sliding under the belt in a crash,
and would increase the risk of spinal and
abdominal injuries. The allowable location for the
shoulder belt is specified in Figure 1 of the current
FMVSS No. 210.
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BILLING CODE 4910–59–C
• The agency also proposes that the
seat belt anchorages, both torso and lap,
be required to be integrated into the seat
structure. NHTSA proposes such
integration because if we do not, we are
concerned that some manufacturers
could incorporate some seat belt
anchorages into the bus floor, sidewall,
or roof. Such installation into places
other than the seat structure could
potentially injure unbelted school bus
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passengers in a crash, or obstruct
passengers during emergency egress.
However, we seek comment on whether
there are torso and lap belt anchorage
designs available, other than integrated
into the seat back, that would not
impede access to emergency exits or
become an injury hazard to unbelted
passengers.
Improperly designed lap belts include
those in which the buckle stalk is too
long and the lap belt portion of the belt
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assembly rides high on the 6-year-old
child’s abdomen. For a proper fit, the
lap belt portion must fit low across the
hips so that the crash loads are
distributed across the pelvis and not the
abdominal area. Loading of the
abdomen rather than the pelvis
increases the risk of internal injuries
caused by the seat belt penetration into
the soft tissue of the abdomen.
We are aware that lap belts supplied
to some states have a long buckle end
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that causes the lap belt to not fit low
across the hips of the passengers. The
long buckle end also causes problems
with securing child restraints.22
However, our understanding is that long
buckle ends have been provided out of
a privacy concern about school bus
personnel fastening lap belts near the
crotch area of young passengers.
Comments are requested on whether
long buckle stalks should be retained on
lap belts because of the privacy issues,
even if the long buckle stalks may result
in misplacement of the lap belt across
the child’s abdomen and difficulty in
child restraint attachment.
• Seat belt anchor strength for lap/
shoulder belts. Small school buses have
been required to have lap belts since the
issuance of FMVSS No. 222. The
anchorages for these lap belts have had
to be certified to FMVSS No. 210.
Standard No. 210 specifies that for
multiple seat belts anchored to the same
seat, the belts are pulled
simultaneously.
In today’s proposal to require lap/
shoulder belts in small school buses, we
propose that small school buses should
meet the existing small school bus
anchorage strength requirements for lap/
shoulder belts in FMVSS No. 210. Those
existing strength requirements, specified
in S4.2.2 for lap/shoulder belt
anchorages, specify that the torso
portion of the lap/shoulder belt be
tested simultaneously with the lap belt
portion at 13,344 N (3,000 pounds) each
for each belt loop. For example, a threeposition school bus seat is required to
withstand an 80 kN (18,000 pound) test
load. The calculation for the seat belt
anchorage load requirement in a three
passenger seat is (three times the
shoulder belt plus three times the lap
belt applied simultaneously) = ((3 ×
13,344 N) + (3 × 13,344 N)) = 80,064 N
(18,000 pounds).
• Seat belt retractors. For school bus
seat belts, there is at present no
requirement for seat belt retractors. This
is because the only seat belt systems
currently installed in school buses are
lap belts where retractors are not needed
for the seat belt system to function
properly. We propose to add a new
section of regulatory text (S7.1.5 to
FMVSS No. 208) to ensure that
retractors are provided for school bus
lap/shoulder seat belt assemblies, and
that the retractors meet the same
requirements as seat belt retractors for
passenger cars, trucks and multipurpose
passenger vehicles.
• Maximum number of lap/shoulder
seat belts and minimum seat width. In
S4.1 of FMVSS No. 222, NHTSA
currently considers the number of
seating positions on a bench seat to be
the width of the bench seat in
millimeters (W), divided by 381 and
rounded to the nearest whole number.
This W value is used to calculate the
compartmentalization requirements for
seat backs on all school buses and the
number of lap belt only seating
positions that must meet the provisions
of FMVSS No. 208 and 210 for small
school buses. The agency will continue
to consider W to be the number of
seating positions per bench seat with
optional provided lap belts on large
school buses as well as the
compartmentalization requirements for
all school buses, except that the divisor
will be 380 rather than 381. (Using 380
instead of 381 would just be for
simplicity.) However, for the seating
positions on small school buses with
required lap/shoulder belts and on large
school buses with optional lap/shoulder
belts, we are defining the number of
seating positions (Y) in a slightly
different way. Y is the total seat width
in millimeters divided by 380, rounded
down to the nearest whole number.
Under the definitions of W and the
proposed definition of Y, a 1,118 mm
(44 inch) wide seat would have W = 3
seating positions for the purposes of
calculating the magnitude of the
compartmentalization requirements to
apply to the seat back, but only Y = 2
seating positions for determining the
lap/shoulder belts installed on the
seat.23 The result of this ‘‘Y’’ calculation
would be that each passenger seating
position in a school bus seat with a lap/
shoulder belt would have a minimum
seating width of 380 mm (15 inches). A
proposed minimum seating position
width of 15 inches for seats with lap/
shoulder belts is needed because school
buses are typically purchased based on
maximum seating capacity, and we seek
to ensure that manufacturers will not
install lap/shoulder belt anchorages that
are so narrowly spaced that they would
only fit the smallest occupants.
• FMVSS No. 207, Seating Systems.
At present, FMVSS No. 207 specifically
excludes all bus passenger seats from its
general performance requirements.
FMVSS No. 207 tests the forward
strength of the seat attachment to the
vehicle by replicating the load that
would be applied through the seat
22 The short buckle length is recommended in
NHTSA’s pamphlet on the Proper Use of Child
Safety Restraint Systems in School Buses. https://
www.nhtsa.dot.gov/people/injury/buses/
busseatbelt/.
23 ‘‘Y’’ would also be used to determine the loads
to be applied to the shoulder belts for the quasistatic test, discussed below in this preamble. See
also paragraphs S5.1.6.5.5(a) and (b) of the
proposed regulatory text.
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center of gravity by inertia in a 20 g
vehicle deceleration. If seat belt anchors
are attached to the seat, FMVSS No. 207
requires that the FMVSS No. 210
anchorage load be applied at the same
time the FMVSS No. 207 inertial load is
applied. Both loads are applied
simultaneously because during a crash,
the seat with an integrated seat belt
(such as the seat in a school bus) will
have to sustain the loading due to both
the seat mass and the seat belt load from
the restrained occupant.
The agency is proposing to apply
FMVSS No. 207 to small school buses
with lap/shoulder belts because the load
imposed by FMVSS No. 207 appears to
be greater than the load that would be
imposed by FMVSS No. 222’s seat
performance requirements (S5.1.3). If
we assume a seat mass of 35 kg (77
pounds),24 the FMVSS No. 207 load
would be 6,867 N (1,544 pounds). For
a school bus seat with two seating
positions, the FMVSS No. 210 load
would be a total of 53,376 N (12,000
pounds). So if FMVSS No. 207 were
applied it would add 12 percent
[((53,376 N + 6,867 N)/53,376 N) ¥ 1)]
to the total load. This would result in a
more stringent test procedure.
Comments are requested on whether
FMVSS No. 207 should be applied to
small school bus passenger seats.
• A newly-developed ‘‘quasi-static’’
test requirement would apply to test
school bus seats with lap/shoulder belts
to ensure that the top of the seat back
incorporating the seat belt anchorage
does not pull too far forward due to the
torso belt loading of the belted occupant
and jeopardize the protection of
unbelted passengers to the rear of the
belted occupants. The quasi-static test is
discussed in the next section. The quasistatic test requirements would be in
addition to existing
compartmentalization requirements for
seat performance (e.g., seat performance
forward, S5.1.3 of FMVSS No. 222, and
seat performance rearward, S5.1.4), and
would be in addition to the FMVSS No.
210 test for the seat belt anchorages, and
would be in addition to the FMVSS No.
207 test. A new school bus seat (test
specimen) would be used for each of
these tests.
c. Additional Occupant Protection
Requirements for Large School Buses
With Voluntarily-Installed Lap/Shoulder
Seat Belts
• Large school buses with
voluntarily-installed lap/shoulder seat
belts would be subject to the
24 A 991 mm (39 inch) wide C.E. White seat
weights 34.5 kg (76 pounds). See www.cewhite.com/
cr-series-prod_info.html.
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requirements described above for lap/
shoulder belts on small school buses,
except FMVSS No. 207 would not apply
to the passenger seats,25 and as
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25 The agency does not believe there is a need to
apply FMVSS No. 207 to large school buses that do
not have seat belts because the load imposed by 207
appears to be lower than the load that would be
imposed by FMVSS No. 222’s seat performance
requirements (S5.1.3). Under FMVSS No. 222, there
are two forward forces applied to the seat back, by
a lower bar and an upper bar. The lower bar force
has a maximum value of 3,114 N (700 pounds)
times the number of seating positions. In the seat
performance (forward strength) test, after its initial
application, the lower bar load is then reduced by
half, and then the loading bar is locked in place.
Following this, the upper loading bar is applied.
The upper loading bar force must stay in a force
deflection curve that has a minimum value of 4,448
N (1,000 pounds) and a maximum of 10,676 N
(2,400 pounds) once the loading bar displaces more
than 127 mm (5 inches). If we assume a load in the
middle of the force/deflection range, the total
forward force on the seat back is 7,562 N (1,700
pounds). In comparison, if we assume a seat mass
of 35 kg (77 pounds), the FMVSS No. 207 inertial
loading applied to this school bus seat would be
6,867 N (1,544 pounds). Thus, the FMVSS No. 222
forward seat strength loads for a large school bus
are a reasonable substitute for the FMVSS No. 207
inertial loads. Likewise, the agency does not believe
there is a need to apply FMVSS No. 207 to large
school buses that do have seat belts. The agency is
proposing FMVSS No. 210 seat belt anchorage loads
for large school buses, and has found that the
proposed loads are in excess of peak loads that were
applied to the attachment of the seat to the sled test
fixture in a 12 to 13 g sled test simulating a large
school bus barrier crash. Thus, this load
measurement captured the inertial loading of the
seat. It can therefore be argued that for large school
bus seats, the proposed FMVSS No. 210 anchorage
loading would exceed loading that incorporates the
seat inertial loading, albeit at a lower deceleration
level than the 20 g value required by FMVSS No.
207.
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explained in the next section, the quasistatic test procedures for small school
buses would slightly vary from those
applying to seats on large school buses
with voluntary lap/shoulder belts, to
account for the relative severity of the
anticipated frontal crash conditions for
each school bus type.
The agency proposes that for large
school buses with voluntarily installed
lap/shoulder seat belts, the FMVSS No.
210 anchorage strength requirement
should be identical to the requirements
for passenger seat belt anchorages in
smaller vehicles. We are not aware of
any practicability concerns with
meeting such anchorage strength
requirements since the proposed level of
performance for large school buses is
already required of all other vehicles to
which FMVSS No. 210 applies. For lap/
shoulder belts, the torso and body
blocks will be pulled at 13,334 N (3,000
pounds).
However, the agency recognizes that
large school bus vehicles experience
lower crash forces in the passenger
compartment than do small school
buses and other passenger motor
vehicles. Part of the reason for the
difference in crash deceleration is that
the large bus body is designed to slide
relative to the underlying frame as
observed in the frontal barrier crash test.
Specifically, the large school bus
experienced about 12–13 g peak
deceleration during a 48.3 km/h (30
mph) frontal crash into a rigid barrier,
compared to about 25 g for a small
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school bus. In real world vehicle-tovehicle crashes, large school buses will
also experience lower crash forces than
would a small school bus in a similar
crash. This difference is due to the
greater mass of the large bus and
consequent lower change in crash
forces.
During the development of this
NPRM, NHTSA measured the dynamic
loads to the seat belt anchorages on lap/
shoulder belt-equipped two-passenger
school bus seats from C.E. White
Corporation and IMMI during crash
simulation sled testing. The forces on
the seat anchorages were measured
using load cells attached to the sled
buck and the attachment locations of the
seat structure. The test was conducted
using the 48.3 km/h (30 mph) school
bus crash pulse that was used in the
school bus research program. The seats
had two 50th percentile adult male
dummies restrained in lap/shoulder
belts and two unbelted 50th percentile
adult male dummies that struck the seat
back.
The total loads for both seating
positions transmitted from the lap/
shoulder belts, through the seat
structure and anchorages to the floor for
each seat are shown in Figures 2 and 3
for the C.E. White and IMMI seats,
respectively. The highest loads
experienced by the C.E. White seats
revealed that the force was
approximately 17,500 N (3,934 pounds)
per seating position.
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This testing suggested that the total
peak dynamic loading sustained by the
seat belts was about 2⁄3 of that applied
in FMVSS No. 210. Notwithstanding the
above data, the agency believes that the
anchorage strength provided by FMVSS
No. 210 provides the foundation for seat
belt performance and there is value in
maintaining consistency in this
foundation. We understand that this
higher factor of safety may result in
seats and anchorages being constructed
with heavier materials and may in turn
increase the weight and cost of
providing seat belts on large school
buses. However, it is also possible that
those putting seat belt anchorages on
large school buses may use existing
designs for small school buses that have
always needed to meet the same
strength level that is now being
proposed for large school buses.
We request comment on the strength
levels being proposed for large school
buses in FMVSS No. 210. Would it be
appropriate to reduce the strength level
since the crash environment for large
school buses will likely be less severe
than for small school buses? How much
could the load be reduced and still
provide an appropriate safety margin in
a variety of crash scenarios? What
would be the cost and weight savings
associated with a lesser requirement?
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d. Additional Requirements for Large
School Buses With Voluntarily-Installed
Lap Belts
New large school buses with
voluntarily-installed lap belts would be
required to meet the requirements
described in subsection (a) of this
section of the preamble, and the
requirements proposed in this
paragraph. This NPRM proposes that
seat belt anchorages would have to meet
FMVSS No. 210 requirements of a
loading force of 22,240 N (5,000
pounds) per seating position. This
would be consistent with the existing
lap belt loading requirement for small
school buses and light vehicles with lap
belt only systems.
VII. Quasi-Static Test for Lap/Shoulder
Belts on Small and Large School Buses
The agency has developed a quasistatic test procedure for lap/shoulder
belt-equipped seats in school buses and
proposes to apply this test to small and
large school buses equipped with lap/
shoulder belts. The test is intended to
address possible safety problems caused
by having both belted and unbelted
passengers on the same school bus.
School bus seats designed to provide
compartmentalized protection must
contain the child between well-padded
seat backs that provide controlled ride-
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down in a crash. A school bus seat with
a lap/shoulder belt would have the torso
(shoulder) belt attached to the seat back.
In a crash involving a belted child and
an unbelted child aft of the belted
occupant, the seat back would be
subject to consecutive force applications
from the belted occupant’s torso loading
the seat back and the force generated by
impact of the unbelted passenger. The
quasi-static test replicates this doubleloading scenario and specifies limits on
how far forward the seat back may
displace. The test helps ensure that the
top of a seat back does not pull too far
forward and jeopardize the protection of
compartmentalized passengers to the
rear of the belted occupants, or diminish
the torso restraint effectiveness for lap/
shoulder belted occupants.26
The agency developed the quasi-static
test by performing a sled test using the
same large school bus crash pulse that
was used in the school bus research
program. We measured the loads on the
shoulder belts and both lower parts of
the lap belt. Two unbelted 50th
percentile male dummies were
positioned behind the seat that
contained two restrained 50th percentile
male dummies. Visual observation of
seat kinematics and load cell data
produced by the shoulder belts from
this test revealed the following sequence
of events:
1. The knees of the unbelted dummy
to the rear struck the back of the forward
seat, causing some seat back deflection.
2. The shoulder belt was loaded by
the restrained dummy in the forward
seat.
3. The shoulder belt load was reduced
as the seat back to which it was attached
deflected forward.
4. The shoulder belt loads reduced to
approximately zero when the unbelted
dummies’ chests struck the forward seat
back.
5. The forward seat back deflected
further forward as the energy from the
unbelted dummies was absorbed.
This crash scenario is replicated in
the quasi-static test. The load
requirement for the quasi-static test is
dependant upon the number of seating
positions and also the likely seat
26 A quasi-static test was developed and is being
proposed instead of a dynamic test because school
bus manufacturers are familiar with quasi-static
testing. The existing requirements in FMVSS No.
222 use a quasi-static test (the current
compartmentalization seat performance
requirements in S5.1.3) to assess the capability of
the school bus seat to provide protection in a frontal
crash. The agency believes that by using a quasistatic procedure for testing school bus seats,
manufacturers would be able to test a large number
of seats and a variety of design configurations
without incurring the delay and additional cost of
sending each configuration to an outside testing
facility.
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capacity. A seat that has the minimal
allowed overall seat width for either a
two or three occupant seat will have a
reduced loading requirement from other
seats.27 The agency is proposing that a
5,000 N (1,124 pounds) load per
occupant be applied in the quasi-static
test; however, seats with a minimal
allowed overall seat width would have
a 3,300 N (750 pounds) load per
occupant applied.28
The reason for the reduced load
requirement for the minimal width seats
is that students at the 50th percentile
male or larger size would not be able to
simultaneously occupy each of the
seating positions. For example, a 45
inch seat would have a seating capacity
of three, or the minimum allowed
overall seat width for a three occupant
seat. However, a common practice used
for the seating configuration in large
school buses to be equipped with lap/
shoulder belts has been to install a 1,143
mm (45 inches) three position seat on
one side of the aisle and a 762 mm (30
inches) two position seat on the other
side of the aisle in each row of the bus.
To accommodate students larger than
the 5th percentile female, schools
typically seat two persons in the 1,143
mm (45 inches) seat and one person in
the 762 mm (30 inches) seat. Because
the seat width is not sufficient to
accommodate the 50th percentile
occupants at the full seating capacity
(i.e., three in the 1,143 mm and two in
the 762 mm seats), we are proposing
that the quasi-static torso belt test have
a reduced load.29
We believe that if the seat has the
minimal allowed overall seat width it is
reasonable to reduce the total torso belt
loading applied to the seat in the quasistatic test to a per occupant value below
the loading applied for larger seating
width, since larger occupants would not
occupy those seats to the full seating
capacity. To estimate the appropriate
load value, we assume the worst case
loading condition is approached when
27 A school bus bench seat has the minimum
allowed overall width if the total seat width in
millimeters minus 380Y is 25 mm (1 inch) or less.
28 Based on the assumption of a 5th percentile
female occupant in a seating position as opposed
to a 50th percentile male, we tentatively conclude
that the proposed torso body block pull should be
reduced in that situation to 3,300 N (750 pounds)
from 5,000 N (1,124 pounds) or by approximately
the same percentage as the ratio of the mass of a
5th percentile female to that of a 50th percentile
male, i.e., 65 percent [48 kg/74 kg].
29 We note that the total loading applied for a 45
inch seat under this proposal would be 9,900 N
(3,300 N × three 5th percentile occupants) as
compared to 10,000 N if it were tested for two 50th
percentile occupants. A 30 inch seat would have a
total load of 6,600 N (3,300 N × two 5th percentile
occupants) rather than 5,000 N total load if one 50th
percentile occupant were seated in the seat.
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every seating position is occupied by a
child as large as a 5th percentile adult
female.30
We also believe the proposed loading
requirements are practicable. Testing at
NHTSA’s Vehicle Research Test Center
revealed that existing lap/shoulder belt
equipped seats could meet a torso body
block pull of 3,300 N (750 pounds) per
occupant.31 NHTSA in-vehicle testing at
MGA Research Corporation of threeposition, 1,143 mm (45 inches) seats
with lap/shoulder belts in a large school
bus, also revealed that these seats would
pass the quasi-static test.32
For small school buses, this NPRM
proposes that a 7,500 N (1,686 pounds)
load per occupant be applied in the
quasi-static test; however, seats with a
minimal allowed overall seat width
would have a 5,000 N (1,124 pounds)
load per occupant applied. As explained
in NHTSA’s ‘‘Technical Analysis to
Support Upgrading the Passenger Crash
Protection in School Buses,’’ the torso
belt loads are higher than for large
school buses because small school buses
experience higher crash accelerations
than large school buses.
a. Stage 1: Torso Belt Anchorage
Displacement
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This part of the quasi-static test
replicates steps 1 and 2 of the crash
scenario above. The proposed procedure
uses the knee and top loading bars that
are currently specified in S5.1.3 of
FMVSS No. 222 (seat back strength),
which replicate a passenger’s knee and
torso loading the forward seat back 33
and the FMVSS No. 210 upper torso
30 Of course, the seat could be used by occupants
of other sizes and in other combinations. For
example, two 50th percentile male occupants might
occupy the outboard seating positions in a three
position, 1,143 mm (45 inch) seat or a 50th
percentile male and a smaller child might occupy
a two seating position, 762 mm (30 inch) seat.
However, we believe the loading applied by other
occupant combinations will not result in drastically
higher loading applied to the seat through the seat
belts.
31 VRTC testing determined that the 1,143 mm (45
inch), three position seat and a 762 mm (30 inch),
two position seat would collapse during the quasistatic test when a torso body block load of 5,000 N
(1,124 pounds) at each seating position was used.
32 Research Testing For FMVSS No. 222, School
Bus Passenger Seating and Crash Protection, Report
No. 222R–MGA–2007–001, September 2006, MGA
Research Corporation.
33 The current knee loading test procedure
requires that initially a force of 3,114 N (700
pounds) times the number of seating positions in
the test seat (w) be applied to the seat back within
5 and not more than 30 seconds, and then the force
is reduced to 1,557 N (350 pounds) times w. The
knee loading bar is locked in this position for the
remainder of the test. The current top loading test
procedure requires an additional force through the
top loading bar until 452 joules (4,000 inch-pounds)
times w of energy is absorbed by the seat back.
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body block.34 The test procedure uses
the bottom loading bar to replicate the
knee loading by the unbelted rear
passengers (based on W), then specifies
a pull test on the shoulder belts at each
seating position in the seat to replicate
loading of the shoulder belt by the
belted passengers (based on Y). Under
the proposed test procedure, the large
school bus shoulder belts would be
pulled using the upper torso body block
specified in Figure 3 of FMVSS No. 210
with a force of 5,000 N (1,124 pounds)
at each seating position for large school
buses, and a force of 7,500 N (1,686
pounds) for small school buses.35 The
proposed rule (S5.1.6.5.4) includes a
very specific procedure for positioning
the torso body block. The torso body
block force would be applied in not less
than 5 and not more than 30 seconds.
We found that an applied load of 5,000
N (1,124 pounds) for large school buses
was necessary to replicate the torso belt
loading from the sled test and to get the
similar seat response observed from
high speed video. This is slightly higher
than twice the highest reading of the
shoulder belt load cell (2,161 N). For
small school buses, a higher force is
proposed because the small school bus
crash pulse has twice the peak
acceleration of the large school bus, i.e.,
approximately 25 g.36
At this mid-point of the quasi-static
test when the torso block force is being
applied, NHTSA would measure
displacement of the torso belt
anchorages. The criterion for passing
this part of the test is that the torso belt
anchorages must not displace forward
more than a specified value. The value
is a function of the vertical location of
the anchorage and the angle of the seat
back surface that compartmentalizes the
occupants rearward of the seat being
tested, i.e., the posterior surface of the
seat back.
Basically, for large school buses, the
allowable displacement is equivalent to
the amount of displacement that would
result from the seat back deflecting
forward 10 degrees past a vertical
plane.37 For large school buses, we
propose that q (theta) in the equation
34 The agency is considering a rulemaking that
would replace the torso body block in FMVSS No.
210 with an updated force application device. If the
upper torso body block in FMVSS No. 210 is
changed, the body block discussed in this quasistatic procedure proposed today may be changed to
the new force application device as well.
35 As discussed earlier in this section, these 5,000
N (1,124 pounds) and 7,500 N (1,686 pounds)
values would be reduced depending on the width
of the seat.
36 The rational for the load application is
explained in the agency’s Technical Analysis.
37 The derivation of the equation defining this
displacement limit is explained in the agency’s
Technical Analysis.
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below be limited to 10 degrees as shown
in Figure 9 of the proposed regulatory
text. Thus, the total allowable forward
horizontal displacement for large school
buses would be:
Large School Bus Displacement Limit =
(AH + 100)(tanq + 0.174/cosq) mm.
For small school buses, the
displacement limit would be equivalent
to the amount of displacement resulting
from a seat back deflecting forward 15
degrees past a vertical plane. The
displacement limit would be
determined using the equation:
Small School Bus Displacement Limit =
(AH + 100)(tanq + 0.259/cosq) mm.
The allowed displacement for small
school buses is greater than the limit for
large school buses to account for our
concerns about practicability of small
school buses meeting the displacement
criterion.
As noted above, the goal of the torso
belt anchorage displacement criterion is
two-fold. The first goal is to assure that
the seat back to which the torso belt is
anchored has sufficient strength to
restrain and protect the belted occupant
in a frontal crash. The second goal is to
assure that the seat back is still in a
sufficiently upright position to
compartmentalize unbelted occupants
to the rear. Thus, we believe that the
displacement limit should be narrow, to
ensure that seat backs deviate as little as
possible from the initial upright
position.
b. Stage 2: Energy Absorption Capability
of the Seat Back
The quasi-static test continues with
procedures to replicate steps 3, 4 and 5
of the crash scenario above. After the
torso anchorage displacement is
measured, the torso body block load is
released. Immediately after this load is
released, forward load is applied to the
seat back through the top loading bar.
The seat back must be able to absorb the
same amount of energy per seating
position (452 joules (4,000 in-pounds))
as is required of a seat back under the
compartmentalization requirement.
However, for this quasi-static test, the
seat back need not perform such that the
top loading bar force must stay in the
force/deflection corridor specified for
the compartmentalization
requirement.38 This is because the torso
body block load may have generated
stresses in the seat frame that exceed the
38 A separate FMVSS No. 222 forward loading test
is still performed on a different test specimen, one
that was not subjected to the quasi-static test, to
assure that in a crash, if the seat were not occupied
by a belted passenger and it were impacted by an
unbelted rearward passenger, the seat would meet
the force/deflection corridor.
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elastic limit of the material and result in
residual strain. The seat back would still
need to have the capability to absorb
452 joules of energy from the unbelted
rear occupant, but the manner of
absorbing the energy would not be as
controlled as when impacting a seat
back that had not been subjected to the
previous loading from the seat belts.
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c. Request for Comments
• We note that in the above quasistatic procedure, no load is applied
through the pelvis body block. This is
because a visual assessment showed the
desired seat response could be achieved
with just the torso body block load.
Also, a main focus of the test is to assure
that the top of the seat back does not
pull too far forward and jeopardize the
protection of compartmentalized
passengers to the rear of the belted
occupants. The agency seeks comment
on whether the quasi-static test should
apply a pelvis block loading.
• The agency also seeks comment on
the proposal to have a more rigorous
quasi-static seat test for small school
buses than for large school buses. We
also seek comment on the appropriate
level of the torso block loading to be
applied during the test and allowable
anchorage displacement. Would it be
appropriate and reasonable to impose
the same displacement limit as is being
proposed for large school buses?
• Comments are requested on the
validity of the assumption that the
timing of the seat loading is such that
the seat belt loading will essentially be
finished before the upper part of the seat
back is loaded by the rear
compartmentalized dummy.
• The agency also seeks comment on
the proposed procedure (see S5.1.6.5.4
of the proposed rule) for positioning the
torso block. Is the proposed procedure
sufficiently clear? Are there ways to
improve the clarity of the test
procedure?
VIII. Lead Time
If the proposed changes in this NPRM
are made final, NHTSA proposes a one
year lead time for school bus
manufacturers to meet the new
minimum seat back height (24 inches),
seat cushion test and barrier
requirements for all school buses, since
there is limited or no development
necessary for these changes.
We note that lap/shoulder belts are
currently available from two suppliers.
We are aware of at least one school bus
manufacturer (Collins) that is already
manufacturing its own lap/shoulder belt
seats. We further propose a one year
lead time for meeting requirements for
voluntarily installed seat belts in large
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school buses and a three year lead time
for meeting mandatory installation in
small school buses. We believe three
years are necessary for small school
buses since some design, testing, and
development will be necessary to certify
compliance to the new requirements.
Nothing in this NPRM proposes to
require that large school buses be fitted
with seat belt anchorages, with lap belts,
or lap/shoulder belts.
If the proposed changes in this NPRM
are made final, NHTSA proposes that
optional early compliance be permitted.
IX. Rulemaking Analyses and Notices
Executive Order 12866 and DOT
Regulatory Policies and Procedures
This rulemaking document was not
reviewed by the Office of Management
and Budget under E.O. 12866 and is not
considered to be significant under E.O.
12866 or the Department’s Regulatory
Policies and Procedures (44 FR 11034;
February 26, 1979). NHTSA has
prepared a preliminary regulatory
evaluation (PRE) for this NPRM.39
This NPRM proposes: (a) For all
school buses, to increase seat back
height from 20 inches to 24 inches, and
to require a self-latching mechanism for
seat bottom cushions that are designed
to flip-up 40; and (b) for small school
buses (GVWR of 4,536 kg (10,000 lb) or
less, require lap/shoulder belts instead
of just lap belts. The belt systems would
be required to meet specifications for
retractors, strength, location and
adjustability. Seat backs with lap/
shoulder belts would be subject to a
quasi-static test so that the seat backs
are strong enough to withstand the
forces from a belted passenger and force
imposed on the seat from unbelted
passenger seated behind rear the belted
occupant. This NPRM also proposes: (c)
Performance requirements for
voluntarily-installed seat belts on large
(over 4,536 kg (10,000 lb)) school buses.
For large school buses with voluntarilyinstalled lap/shoulder belts, the vehicle
would be subject to the requirements
described above for lap/shoulder belts
on small school buses, except that
applied test forces and performance
limits would be adjusted so as to be
39 NHTSA’s preliminary regulatory evaluation
(PRE) discusses issues relating to the potential
costs, benefits and other impacts of this regulatory
action. The PRE is available in the docket for this
NPRM and may be obtained by contacting Docket
Management at the address or telephone number
provided at the beginning of this document.
40 The agency estimates that a self-latching
mechanism on flip-up seat bottoms would cost less
than $3 per seat, or $66 per bus. This cost was not
included in the estimates given below. Comments
are requested on the number of school buses and
school bus seats affected by the seat latching
requirement.
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representative of those imposed on large
school buses. Large school buses with
voluntarily-installed lap belts would be
required to meet anchorage strength
requirements. This NPRM does not
require seat belts to be installed on large
school buses. The proposed
performance requirements for seat belts
on large school buses affect large school
buses only if purchasers choose to order
seat belts on their vehicles.
School Bus Fleet 2007 Fact Book on
U.S. school bus sales for the sales years
2001–2005 reports that for each of these
years on average, approximately 40,000
school buses were sold. NHTSA
estimates that of the 40,000 school buses
sold per year, 2,500 of them were 10,000
pounds GVWR or under. The other
37,500 school buses were over 10,000
pounds GVWR. Four states currently
require high back seats (Illinois, New
Jersey, New York, and Ohio). These
states have 21.7 percent of the sales.
Thus, the high back seat incremental
costs apply to 78.3 percent of these sales
or 1,958 buses that are 10,000 pounds
GVWR or under and 29,362 buses that
are over 10,000 pounds GVWR.
Small School Buses
NHTSA estimates that the costs of this
rulemaking would be the incremental
cost of the higher (24 inch) seat back
($45 to $64 per small school bus for 78.3
percent of the fleet) plus the
incremental cost for lap/shoulder belts
over lap belts of $1,121 to $2,417. This
would be a total incremental cost per
school bus of $1,166 to $2,481 per bus
for those states without high back seats.
If it is assumed that in a given year,
2,500 small school buses are sold, for all
small school buses, the total
incremental costs of this rulemaking are
estimated to be from $2,889,000 ($45 ×
1,958 + $1,121 × 2,500 small school
buses) to $6,167,000 ($64 × 1,958 +
$2,417 × 2,500 small school buses).
The estimated benefits resulting from
the higher seat backs and lap/shoulder
belts on small school buses is, per year,
37.2 fewer injuries, and 0.4 fewer
fatalities.
Large School Buses
Costs of Higher Seat Backs on Large
School Buses—If this NPRM were made
final, all large school buses would be
required to have the higher seat backs of
24 inches. NHTSA estimates the cost
per large school bus of the higher seat
back to be $125. If this NPRM were
made final, NHTSA estimates that the
total costs of the higher seat backs on
large school buses to be $3,680,000
(29,362 large school buses times
$125.40).
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Benefits of Higher Seat Backs on
Large School Buses—If this NPRM were
made final, the benefits from higher seat
backs on large should buses is estimated
to be 29.6 fewer injuries per year, and
0.2 fewer fatalities per year.
Costs and Benefits of Performance
Requirements for Voluntarily-Installed
Belts on Large School Buses—As earlier
noted, nothing in this rulemaking would
require any party to install lap or lap/
shoulder belts at passenger seating
positions in large school buses. Instead,
this rulemaking would specify
performance requirements that
voluntarily-installed lap or lap/shoulder
belts at passenger seating positions must
meet. Lap or lap/shoulder belts that are
now installed in large school buses
would be affected by this rulemaking, in
that the voluntarily-installed belt
systems would be subject to the
performance requirements set forth in
this NPRM whereas currently the
systems are not subject to any Federal
standard. The agency is unable to
estimate the costs and benefits of this
part because not enough is known about
the requirements that state and local
authorities now specify for the
performance of seat belt systems on
large school buses. Comments are
requested on the added costs that would
result from the belt systems having to
meet the performance requirements
specified in this NPRM.
Overview of Costs and Benefits
Costs of High Back Seats and Lap/
Shoulder Belts for Small School Buses,
and of High Back Seats for Large School
Buses
Small School Buses: Adding together
the high back seat incremental cost of
$45 to $64 to the incremental cost for
lap/shoulder belts over lap belts of
$1,121 to $2,417, results in a total
incremental cost of $1,166 to $2,481 per
bus.
Large School Buses: The incremental
cost for high back seat is estimated to be
$125 per bus.
TABLE 1.—TOTAL COSTS (PER BUS AND FOR THE FLEET)
[$2006]
Large buses
Per Bus Costs ................................
Annual Fleet Costs ........................
Combined Annual Fleet Costs
Small buses
Small buses
66 passenger ................................
$125 ..............................................
$3.7 million ...................................
$6.6 to $9.9 Million.
14 Passenger ...............................
$1,166 ...........................................
$2.9 million ...................................
20 Passenger.
$2,481.
$6.2 million.
Benefits of High Back Seats and Lap/
Shoulder Belts for Small School Buses,
and of High Back Seats for Large School
Buses
The benefits of the proposal for small
school buses and large school buses are
estimated as shown below in Table 2:
TABLE 2.—TOTAL BENEFITS
Small school bus
Injuries
Large school bus
Fatalities
Injuries
Combined below1
High Back Seat ........................................
Lap/Shoulder Belts ...................................
Total ..................................................
37
37
Total
Fatalities
Injuries
Fatalities
30
0.4
0.4
0.2
30
0.2
n.a.
30
n.a.
0.2
37
67
0.4
0.6
1 We did not have test data to allow us to separate out the high back seats from lap/shoulder belts for small school buses; thus, these data
have been combined.
mstockstill on PROD1PC66 with PROPOSALS
Regulatory Flexibility Act
Pursuant to the Regulatory Flexibility
Act (5 U.S.C. 601 et seq., as amended by
the Small Business Regulatory
Enforcement Fairness Act (SBREFA) of
1996), whenever an agency is required
to publish a notice of rulemaking for
any proposed or final rule, it must
prepare and make available for public
comment a regulatory flexibility
analysis that describes the effect of the
rule on small entities (i.e., small
businesses, small organizations, and
small governmental jurisdictions). The
Small Business Administration’s
regulations at 13 CFR part 121 define a
small business, in part, as a business
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entity ‘‘which operates primarily within
the United States.’’ (13 CFR
§ 121.105(a)). No regulatory flexibility
analysis is required if the head of an
agency certifies that the rule will not
have a significant economic impact on
a substantial number of small entities.
The SBREFA amended the Regulatory
Flexibility Act to require Federal
agencies to provide a statement of the
factual basis for certifying that a rule
will not have a significant economic
impact on a substantial number of small
entities.
NHTSA has considered the effects of
this rulemaking action under the
Regulatory Flexibility Act. According to
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13 CFR Section 121.201, the Small
Business Administration’s size
standards regulations used to define
small business concerns, school bus
manufacturers would fall under North
American Industry Classification
System (NAICS) No. 336111,
Automobile Manufacturing, which has a
size standard of 1,000 employees or
fewer. Using the size standard of 1,000
employees or fewer, NHTSA estimates
that there are two small school bus
manufacturers in the United States (U.S.
Bus Corp. and Van-Con). NHTSA
believes that both U.S. Bus Corp and
Van-Con manufacture small school
buses and large school buses.
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mstockstill on PROD1PC66 with PROPOSALS
I hereby certify that if made final, this
proposed rule would not have a
significant economic impact on a
substantial number of small entities. If
this NPRM were made final, the small
businesses manufacturing small buses
would incur incremental costs ranging
from a low of $1,166 to $2,481 per small
school bus, out of a total cost of $40,000
to $50,000 per small school bus. The
small businesses manufacturing large
school buses would incur incremental
costs of $125 per school bus (out of a
total of more than $70,000) for the costs
of the higher seat backs. The costs of
lap/shoulder belts on large school buses
is not a factor, as nothing in this NPRM
would require lap/shoulder belts or lap
belts at passenger seating positions in
large school buses.
The relatively minimal additional
costs outlined above for large and small
school buses would be passed on to
school bus purchasers. Those
purchasers are required to be sold
school buses if they purchase a new bus,
and to use school buses. Thus, small
school bus manufacturers would not
lose market share if the changes
proposed in this NPRM were made
final. While small organizations and
governmental jurisdictions procuring
school buses would be affected by this
rulemaking in that the cost of school
buses would increase, the agency
believes the impacts on these entities
would not be significant.
Executive Order 13132
NHTSA has examined today’s NPRM
pursuant to Executive Order 13132 (64
FR 43255, August 10, 1999). On July 11,
2007, NHTSA held a public meeting
bringing together a roundtable of state
and local government policymakers,
school bus manufacturers, pupil
transportation associations and
consumer groups to discuss the safety,
policy and economic issues related to
seat belts on school buses (see NHTSA
Docket 28103). No additional
consultation with States, local
governments or their representatives is
contemplated beyond the rulemaking
process. Further, the agency has
concluded that the rulemaking would
not have federalism implications
because it would not have ‘‘substantial
direct effects on the States, on the
relationship between the national
government and the States, or on the
distribution of power and
responsibilities among the various
levels of government.’’ This proposal
would specify performance
requirements for seat belts voluntarily
installed on large school buses, but does
not propose to require the belts on the
large buses.
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Further, no consultation is needed to
discuss the preemptive effect of today’s
rulemaking. NHTSA rules can have
preemptive effect in at least two ways.
First, the National Traffic and Motor
Vehicle Safety Act contains an express
preemptive provision: ‘‘When a motor
vehicle safety standard is in effect under
this chapter, a State or a political
subdivision of a State may prescribe or
continue in effect a standard applicable
to the same aspect of performance of a
motor vehicle or motor vehicle
equipment only if the standard is
identical to the standard prescribed
under this chapter.’’ 49 U.S.C.
30103(b)(1). It is this statutory command
that preempts State law, not today’s
rulemaking, so consultation would be
inappropriate.
In addition to the express preemption
noted above, the Supreme Court has
also recognized that State requirements
imposed on motor vehicle
manufacturers, including sanctions
imposed by State tort law, can stand as
an obstacle to the accomplishment and
execution of a NHTSA safety standard.
When such a conflict is discerned, the
Supremacy Clause of the Constitution
makes their State requirements
unenforceable. See Geier v. American
Honda Motor Co., 529 U.S. 861 (2000).
NHTSA has not outlined such potential
State requirements in today’s
rulemaking, however, in part because
such conflicts can arise in varied
contexts, but it is conceivable that such
a conflict may become clear through
subsequent experience with today’s
standard and test regime. NHTSA may
opine on such conflicts in the future, if
warranted. See id. at 883–86.
National Environmental Policy Act
NHTSA has analyzed this NPRM for
the purposes of the National
Environmental Policy Act. The agency
has determined that implementation of
this action would not have any
significant impact on the quality of the
human environment.
Paperwork Reduction Act
Under the procedures established by
the Paperwork Reduction Act of 1995, a
person is not required to respond to a
collection of information by a Federal
agency unless the collection displays a
valid OMB control number. This NPRM
would not establish any new
information collection requirements.
National Technology Transfer and
Advancement Act
Under the National Technology
Transfer and Advancement Act of 1995
(NTTAA) (Public Law 104–113), ‘‘all
Federal agencies and departments shall
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65525
use technical standards that are
developed or adopted by voluntary
consensus standards bodies, using such
technical standards as a means to carry
out policy objectives or activities
determined by the agencies and
departments.’’ After carefully reviewing
the available information, NHTSA has
determined that there are no voluntary
consensus standards relevant to this
rulemaking.
Executive Order 12988
With respect to the review of the
promulgation of a new regulation,
section 3(b) of Executive Order 12988,
‘‘Civil Justice Reform’’ (61 FR 4729,
February 7, 1996) requires that
Executive agencies make every
reasonable effort to ensure that the
regulation: (1) Clearly specifies the
preemptive effect; (2) clearly specifies
the effect on existing Federal law or
regulation; (3) provides a clear legal
standard for affected conduct, while
promoting simplification and burden
reduction; (4) clearly specifies the
retroactive effect, if any; (5) adequately
defines key terms; and (7) addresses
other important issues affecting clarity
and general draftsmanship under any
guidelines issued by the Attorney
General. This document is consistent
with that requirement. Pursuant to this
Order, NHTSA notes as follows. The
preemptive effect of this proposed rule
is discussed above. NHTSA notes
further that there is no requirement that
individuals submit a petition for
reconsideration or pursue other
administrative proceeding before they
may file suit in court.
Unfunded Mandates Reform Act
The Unfunded Mandates Reform Act
of 1995 requires agencies to prepare a
written assessment of the costs, benefits
and other effects of proposed or final
rules that include a Federal mandate
likely to result in the expenditure by
State, local or tribal governments, in the
aggregate, or by the private sector, of
more than $100 million annually
(adjusted for inflation with base year of
1995). This NPRM would not result in
expenditures by State, local or tribal
governments, in the aggregate, or by the
private sector in excess of $100 million
annually.
Executive Order 13045
Executive Order 13045 (62 FR 19885,
April 23, 1997) applies to any rule that:
(1) is determined to be ‘‘economically
significant’’ as defined under E.O.
12866, and (2) concerns an
environmental, health, or safety risk that
NHTSA has reason to believe may have
a disproportionate effect on children.
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This rulemaking is not subject to the
Executive Order because it is not
economically significant as defined in
E.O. 12866.
Statement in the Federal Register
published on April 11, 2000 (Volume
65, Number 70; Pages 19477–78).
Executive Order 13211
How do I prepare and submit
comments?
X. Public Participation
Executive Order 13211 (66 FR 28355,
May 18, 2001) applies to any
rulemaking that: (1) Is determined to be
economically significant as defined
under E.O. 12866, and is likely to have
a significantly adverse effect on the
supply of, distribution of, or use of
energy; or (2) that is designated by the
Administrator of the Office of
Information and Regulatory Affairs as a
significant energy action. This
rulemaking is not subject to E.O. 13211.
Plain Language
Executive Order 12866 and the
President’s memorandum of June 1,
1998, require each agency to write all
rules in plain language. Application of
the principles of plain language
includes consideration of the following
questions:
• Have we organized the material to
suit the public’s needs?
• Are the requirements in the rule
clearly stated?
• Does the rule contain technical
language or jargon that isn’t clear?
• Would a different format (grouping
and order of sections, use of headings,
paragraphing) make the rule easier to
understand?
• Would more (but shorter) sections
be better?
• Could we improve clarity by adding
tables, lists, or diagrams?
• What else could we do to make the
rule easier to understand?
If you have any responses to these
questions, please include them in your
comments on this proposal.
Regulation Identifier Number (RIN)
The Department of Transportation
assigns a regulation identifier number
(RIN) to each regulatory action listed in
the Unified Agenda of Federal
Regulations. The Regulatory Information
Service Center publishes the Unified
Agenda in April and October of each
year. You may use the RIN contained in
the heading at the beginning of this
document to find this action in the
Unified Agenda.
Your comments must be written and
in English. To ensure that your
comments are correctly filed in the
Docket, please include the docket
number of this document in your
comments.
Your comments must not be more
than 15 pages long. (49 CFR 553.21). We
established this limit to encourage you
to write your primary comments in a
concise fashion. However, you may
attach necessary additional documents
to your comments. There is no limit on
the length of the attachments.
Please submit two copies of your
comments, including the attachments,
to Docket Management at the address
given above under ADDRESSES.
Comments may also be submitted to
the docket electronically by logging onto
the Docket Management System website
at https://www.regulations.gov. Follow
the online instructions for submitting
comments.
Please note that pursuant to the Data
Quality Act, in order for substantive
data to be relied upon and used by the
agency, it must meet the information
quality standards set forth in the OMB
and DOT Data Quality Act guidelines.
Accordingly, we encourage you to
consult the guidelines in preparing your
comments. OMB’s guidelines may be
accessed at https://www.whitehouse.gov/
omb/fedreg/reproducible.html. DOT’s
guidelines may be accessed at
MACROBUTTON HtmlResAnchor
https://dmses.dot.gov/submit/
DataQualityGuidelines.pdf.
How can I be sure that my comments
were received?
If you wish Docket Management to
notify you upon its receipt of your
comments, enclose a self-addressed,
stamped postcard in the envelope
containing your comments. Upon
receiving your comments, Docket
Management will return the postcard by
mail.
mstockstill on PROD1PC66 with PROPOSALS
Privacy Act
How do I submit confidential business
information?
Anyone is able to search the
electronic form of all comments
received into any of our dockets by the
name of the individual submitting the
comment (or signing the comment, if
submitted on behalf of an association,
business, labor union, etc.). You may
review DOT’s complete Privacy Act
If you wish to submit any information
under a claim of confidentiality, you
should submit three copies of your
complete submission, including the
information you claim to be confidential
business information, to the Chief
Counsel, NHTSA, at the address given
above under FOR FURTHER INFORMATION
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CONTACT. In addition, you should
submit two copies, from which you
have deleted the claimed confidential
business information, to Docket
Management at the address given above
under ADDRESSES. When you send a
comment containing information
claimed to be confidential business
information, you should include a cover
letter setting forth the information
specified in our confidential business
information regulation. (49 CFR part
512.)
Will the agency consider late
comments?
We will consider all comments that
Docket Management receives before the
close of business on the comment
closing date indicated above under
DATES. To the extent possible, we will
also consider comments that Docket
Management receives after that date. If
Docket Management receives a comment
too late for us to consider in developing
a final rule (assuming that one is
issued), we will consider that comment
as an informal suggestion for future
rulemaking action.
How can I read the comments submitted
by other people?
You may read the comments received
by Docket Management at the address
given above under ADDRESSES. The
hours of the Docket are indicated above
in the same location. You may also see
the comments on the Internet. To read
the comments on the Internet, go to
https://www.regulations.gov. Follow the
online instructions for accessing the
dockets.
Please note that even after the
comment closing date, we will continue
to file relevant information in the
Docket as it becomes available. Further,
some people may submit late comments.
Accordingly, we recommend that you
periodically check the Docket for new
material.
Appendix A to the Preamble—Proposed
Amendments to Federal Motor Vehicle
Safety Standards
For the convenience of the reader and for
illustration purposes, this appendix generally
lists the proposed amendments according to
the affected standard. This NPRM proposes
to:
a. Amend 207, Seating Systems, to apply
it to school buses with a GVWR of 4,536 kg
(10,000 lb) or less (‘‘small school buses’’).
b. Amend FMVSS No. 208, Occupant
Crash Protection, to:
1. Require lap/shoulder belt at all
passenger-seating positions on small school
buses.
2. Correct a typographical error in the
heading of S4.4.5.
3. Specify lockability requirements for seat
belts on school buses.
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c. Amend FMVSS No. 210, Seat Belt
Assembly Anchorages, to:
1. Specify a seat belt anchorage strength
test of 3,000 pounds each for the torso and
the lap portion of voluntarily-installed lap/
shoulder belt anchorages for passengers in
large school buses.
2. Specify a seat belt anchorage strength
test of 5,000 pounds for voluntarily-installed
lap belt anchorages in large school buses.
3. Add a requirement concerning lap/
shoulder anchorage locations and
adjustability so seat belts on school buses
properly fit passengers from sizes ranging
from an average 6-year-old through a 50th
percentile adult male.
4. Add a requirement that the seat belts be
anchored to the school bus seat structure.
d. Amend FMVSS No. 222, School Bus
Passenger Seating and Crash Protection, to:
1. Increase seat back height from 20 inches
to 24 inches above the seating reference
point, and amend frontal restraining barrier
requirements to make them consistent with
the higher seat back heights.
2. Require lap/shoulder belt restraints
instead of the current lap belts for small
school buses.
3. Require voluntarily-installed lap belts
and lap/shoulder belt systems in large school
buses to meet performance requirements.
4. Add a quasi-static test for all passenger
seats with lap/shoulder belts, to ensure
compatibility between compartmentalization
and lap/shoulder belt systems.
5. Specify a minimum seat belt width of 15
inches for all passenger school bus seats with
lap/shoulder belts.
6. Require all seat bottom cushions that are
designed to flip-up to have a self-latching
mechanism.
It is noted that this list does not include
FMVSS No. 209, because that standard
already applies to seat belt assemblies for use
in buses, a vehicle class that includes—by
definition—school buses. (See ‘‘school bus’’
definition in 49 CFR 571.3.)
List of Subjects in 49 CFR Part 571
Imports, Motor vehicle safety, Motor
vehicles, and Tires.
In consideration of the foregoing,
NHTSA proposes to amend 49 CFR Part
571 as set forth below.
PART 571—FEDERAL MOTOR
VEHICLE SAFETY STANDARDS
1.The authority citation for Part 571
continues to read as follows:
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Authority: 49 U.S.C. 322, 30111, 30115,
30117 and 30166; delegation of authority at
49 CFR 1.50.
2. Section 571.207 is amended by
revising the introductory text of S4.2, to
read as follows:
§ 571.207
systems.
Standard No. 207; Seating
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S4.2. General performance
requirements. When tested in
accordance with S5, each occupant seat
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shall withstand the following forces, in
newtons, except for a side-facing seat, a
passenger seat on a bus other than a
school bus, a passenger seat on a school
bus with a GVWR greater than 4,536
kilograms (10,000 pounds), and a
passenger seat on a school bus with a
GVWR less than or equal to 4,536 kg
manufactured before [insert compliance
date of the final rule].
*
*
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*
*
3. Section 571.208 is amended by
revising S4.4.3.3, adding S7.1.5, and
revising the heading of S4.4.5 and
S4.4.5.1, to read as follows:
§ 571.208 Standard No. 208; Occupant
crash protection.
*
*
*
*
*
S4.4.3.3 School buses with a gross
vehicle weight rating of 4,536 kg (10,000
pounds) or less.
(a) Each school bus with a gross
vehicle weight rating of 4,536 kg (10,000
pounds) or less manufactured before
[compliance date to be inserted] must be
equipped with an integral Type 2 seat
belt assembly at the driver’s designated
seating position and at the right front
passenger’s designated seating position
(if any), and with a Type 1 or Type 2
seat belt assembly at all other
designated seating positions. Type 2
seat belt assemblies installed in
compliance with this requirement must
comply with Standard No. 209 (49 CFR
571.209) and with S7.1 and S7.2 of this
standard. The lap belt portion of a Type
2 seat belt assembly installed at the
driver’s designated seating position and
at the right front passenger’s designated
seating position (if any) must meet the
requirements specified in S4.4.3.3(c).
(b) Each school bus with a gross
vehicle weight rating of 4,536 kg (10,000
pounds) or less manufactured on or after
[compliance date to be inserted] must be
equipped with an integral Type 2 seat
belt assembly at all designated seating
positions. The seat belt assembly at the
driver’s designated seating position and
at the right front passenger’s designated
seating position (if any) shall comply
with Standard No. 209 (49 CFR 571.209)
and with S7.1 and S7.2 of this standard.
The lap belt portion of a Type 2 seat belt
assembly installed at the driver’s
designated seating position and at the
right front passenger’s designated
seating position (if any) shall meet the
requirements specified in S4.4.3.3(c).
Type 2 seat belt assemblies installed on
the rear seats of school buses must meet
the requirements of S7.1.1.5, S7.1.5 and
S7.2 of this standard.
(c) The lap belt portion of a Type 2
seat belt assembly installed at the
driver’s designated seating position and
at the right front passenger’s designated
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seating position (if any) shall include
either an emergency locking retractor or
an automatic locking retractor, which
retractor shall not retract webbing to the
next locking position until at least 3⁄4
inch of webbing has moved into the
retractor. In determining whether an
automatic locking retractor complies
with this requirement, the webbing is
extended to 75 percent of its length and
the retractor is locked after the initial
adjustment. If a Type 2 seat belt
assembly installed in compliance with
this requirement incorporates any
webbing tension-relieving device, the
vehicle owner’s manual shall include
the information specified in S7.4.2(b) of
this standard for the tension-relieving
device, and the vehicle shall comply
with S7.4.2(c) of this standard.
*
*
*
*
*
S4.4.5 Buses with a GVWR of 10,000
lb (4,536 kg) or less, except school
buses, manufactured on or after
September 1, 2007.
S4.4.5.1 Except as provided in
S4.4.5.2, S4.4.5.3, S4.4.5.4, S4.4.5.5 and
S4.4.5.6, each bus as with a gross
vehicle weight rating of 10,000 lb (4,536
kg) or less, except school buses, shall be
equipped with a Type 2 seat belt
assembly at every designated seating
position other than a side-facing
position. Type 2 seat belt assemblies
installed in compliance with this
requirement shall conform to Standard
No. 209 (49 CFR 571.209) and with S7.1
and S7.2 of this standard. If a Type 2
seat belt assembly installed in
compliance with this requirement
incorporates a webbing tension relieving
device, the vehicle owner’s manual
shall include the information specified
in S7.3.1(b) of this standard for the
tension relieving device, and the vehicle
shall conform to S7.4.2(c) of this
standard. Side-facing designated seating
positions shall be equipped, at the
manufacturer’s option, with a Type 1 or
Type 2 seat belt assembly.
*
*
*
*
*
S7.1.5 The seat belt assembly will
operate by means of any emergencylocking or automatic-locking retractor
that conforms to 49 CFR 571.209 to
restrain persons whose dimensions
range from those of an average 6-yearold child to those of a 50th percentile
adult male. The seat back may be in any
position.
*
*
*
*
*
4. Section 571.210 is amended by
revising S2, amending S3 by adding
definitions for ‘‘school bus torso belt
adjusted height’’ and ‘‘school bus torso
belt anchor point,’’ in alphabetical
order, adding S4.1.3, and S4.1.3.1
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through S4.1.3.5, and adding Figure 4 to
the end of the section to read as follows:
§ 571.210 Standard No. 210; Seat belt
assembly anchorages.
*
*
*
*
S2. Application. This standard
applies to passenger cars, multipurpose
passenger vehicles, trucks, buses, and
school buses.
S3. Definitions.
*
*
*
*
*
School bus torso belt adjusted height
means the point at which the torso belt
deviates more than 10 degrees from the
horizontal plane when the torso belt is
pulled away from the seat by a 20 N
force at a location on the webbing
approximately 100 mm from the
adjustment device and the pulled
portion of the webbing is held in a
horizontal plane.
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School bus torso belt anchor point
means the midpoint of the torso belt
width where the torso belt first contacts
the torso belt anchorage.
*
*
*
*
*
S4.1.3 School bus passenger seats.
S4.1.3.1 Seat belt anchorages on
school buses manufactured on or after
[insert compliance date of the final rule]
must be attached to the school bus seat
structure and the seat belt shall be Type
1 or Type 2 as defined in S3 of FMVSS
No. 209 (49 CFR 571.209).
S4.1.3.2 Type 2 seat belt anchorages
on school buses manufactured on or
after [insert compliance date of the final
rule] must meet the location
requirements specified in Figure 4. The
vertical height of the school bus torso
belt anchor point must be at least 520
mm above the seating reference point.
The school bus torso belt adjusted
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height must be adjustable from the torso
belt anchor point to within at least 280
mm of the seating reference point.
S4.1.3.3 School buses with a GVWR
less than or equal to 4,536 kg (10,000
pounds) must meet the requirements of
S4.1.1 of this standard.
S4.1.3.4 School buses with a GVWR
greater than 4,536 kg (10,000 pounds)
manufactured on or after [insert
compliance date of the final rule], with
Type 1 seat belt anchorages, must meet
the strength requirements specified in
S4.2.1 of this standard.
S4.1.3.5 School buses with a GVWR
greater than 4,536 kg (10,000 pounds)
manufactured on or after [insert
compliance date of the final rule], with
Type 2 seat belt anchorages, must meet
the strength requirements specified in
S4.2.2 of this standard.
*
*
*
*
*
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BILLING CODE 4910–59–C
5. Section 571.222 is amended by:
a. Adding to S4, in alphabetical order,
a definition of ‘‘seat bench width’’
b. Revising S4.1, paragraphs S5(a) and
(b), and paragraph S5.1.2;
c. Redesignating S5.1.5 as S5.1.5(a)
and adding paragraph S5.1.5(b);
d. Adding S5.1.6 and S5.1.7; and
revising S5.2.2; and,
e. Adding Figure 8 following Figure 7
at the end of the section.
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The revisions and additions read as
follows:
§ 571.222 Standard No. 222; School bus
passenger seating and crash protection.
*
*
*
*
*
Definitions.
*
*
*
*
*
Seat bench width means the
maximum transverse width of the bench
seat cushion.
*
*
*
*
*
S4.
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S4.1 Determination of the number of
seating positions and seat belt positions
(a) The number of seating positions
considered to be in a bench seat for
vehicles manufactured before [insert
compliance date here] is expressed by
the symbol W, and calculated as the seat
bench width in millimeters divided by
381 and rounded to the nearest whole
number.
(b) The number of seating positions
and the number of Type 1 seat belt
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positions considered to be in a bench
seat for vehicles manufactured on or
after [insert compliance date here] is
expressed by the symbol W, and
calculated as the seat bench width in
millimeters divided by 380 and rounded
to the nearest whole number.
(c) The number of seat belt positions
in a bench seat equipped with Type 2
seat belts for vehicles manufactured on
or after [insert compliance date here] is
expressed by the symbol Y, and
calculated as the seat bench width in
millimeters divided by 380 and rounded
to the next lowest whole number. The
minimum seat bench width for a seat
equipped with a Type 2 belt is 380 mm.
*
*
*
*
*
S5. Requirements.
(a) Large school buses.
(1) Each school bus manufactured
before [insert compliance date] with a
gross vehicle weight rating of more than
4,536 kg (10,000 pounds) shall be
capable of meeting any of the
requirements set forth under this
heading when tested under the
conditions of S6. However, a particular
school bus passenger seat (i.e., a test
specimen) in that weight class need not
meet further requirements after having
met S5.1.2 and S5.1.5, or having been
subjected to either S5.1.3, S5.1.4, or
S5.3.
(2) Each school bus manufactured on
or after [insert compliance date] with a
gross vehicle weight rating of more than
4,536 kg (10,000 pounds) shall be
capable of meeting any of the
requirements set forth under this
heading when tested under the
conditions of S6 of this standard or
§ 571.210. However, a particular school
bus passenger seat (i.e., a test specimen)
in that weight class need not meet
further requirements after having met
S5.1.2 and S5.1.5, or having been
subjected to either S5.1.3, S5.1.4, S5.1.6
(if applicable), or S5.3. Each vehicle
with voluntarily installed Type 1 seat
belts and seat belt anchorages at W
seating positions in a bench seat or Type
2 seat belts and seat belt anchorages at
Y seat belt positions in a bench seat
shall also meet the requirements of:
(i) 4.4.3.3 of Standard No. 208 (49
CFR 571.208);
(ii) Standard No. 209 (49 CFR
571.209), as they apply to school buses;
and
(iii) Standard No. 210 (49 CFR
§ 571.210) as it applies to school buses
with a gross vehicle weight rating
greater than 10,000 pounds.
(b) Small school buses. Each vehicle
with a gross vehicle weight rating of
4,536 kg (10,000 pounds) or less shall be
capable of meeting the following
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requirements at all rear seating
positions:
(1)(i) In the case of vehicles
manufactured before September 1, 1991,
the requirements of §§ 571.208, 571.209,
and 571.210 as they apply to
multipurpose passenger vehicles;
(ii) In the case of vehicles
manufactured on or after September 1,
1991, the requirements of S4.4.3.3 of
§ 571.208 and the requirements of
§§ 571.209 and 571.210 as they apply to
school buses with a gross vehicle weight
rating of 4,536 kg or less;
(iii) In the case of vehicles
manufactured on or after [insert
compliance date of the final rule] the
requirements of S4.4.3.3(b) of § 571.208
and the requirements of §§ 571.209 and
571.210 as they apply to school buses
with a gross vehicle weight rating of
4,536 kg or less; and
(2) The requirements of S5.1.2, S5.1.3,
S5.1.4, S5.1.5, S5.1.6, S5.3, and S5.4 of
this standard. However, the
requirements of §§ 571.208 and 571.210
shall be met at Y seat belt positions in
a bench seat, and a particular school bus
passenger seat (i.e. a test specimen) in
that weight class need not meet further
requirements after having met S5.1.2
and S5.1.5, or after having been
subjected to either S5.1.3, S5.1.4, S5.1.6,
or S5.3 of this standard or § 571.210 or
§ 571.225.
*
*
*
*
*
S5.1.2 Seat back height, position,
and surface area.
(a) For school buses manufactured
before [compliance date to be inserted],
each school bus passenger seat must be
equipped with a seat back that has a
vertical height of at least 508 mm (20
inches) above the seating reference
point. Each school bus passenger seat
must be equipped with a seat back that,
in the front projected view, has front
surface area above the horizontal plane
that passes through the seating reference
point, and below the horizontal plane
508 mm (20 inches) above the seating
reference point, of not less than 90
percent of the seat bench width in
millimeters multiplied by 508.
(b) For school buses manufactured on
or after [compliance date to be inserted],
each school bus passenger seat must be
equipped with a seat back that has a
vertical height of at least 610 mm (24
inches) above the seating reference
point. The minimum total width of the
seat back at 610 mm (24 inches) above
the seating reference point shall be 75
percent of the maximum width of the
seat bench. Each school bus passenger
seat must be equipped with a seat back
that, in the front projected view, has
front surface area above the horizontal
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plane that passes through the seating
reference point, and below the
horizontal plane 610 mm (24 inches)
above the seating reference point, of not
less than 90 percent of the seat bench
width in millimeters multiplied by 610.
*
*
*
*
*
S5.1.5 Seat cushion retention.
*
*
*
*
*
(b) For school buses manufactured on
or after [compliance date to be inserted],
school bus passenger seat cushions
equipped with attachment devices that
allow for the seat cushion to be
removable without tools or to flip up
must have a self-latching mechanism
that is activated when a 22 kg (48.4
pound) mass is placed on the center of
the seat cushion with the seat cushion
in the down position.
S5.1.6 Quasi-static test of
compartmentalization and Type 2 seat
belt performance.
S5.1.6.1 This section applies to rear
passenger seats on school buses
manufactured on or after [compliance
date to be inserted] with a gross vehicle
weight rating of more than 4,536 kg
(10,000 pounds), and that are equipped
with Type 2 seat belt assemblies. When
tested under the conditions of S5.1.6.5.1
through S5.1.6.5.6, the school bus torso
belt anchor point must not displace
horizontally forward more than the
value in millimeters calculated from the
following expression:
(AH + 100) (tanF + 0.174/cosF) mm
where AH is the height in millimeters
of the school bus torso belt anchor point
defined by S4.1.3.2 of FMVSS No. 210
(49 CFR 571.210) and F is the angle of
the posterior surface of the seat back
defined in S5.1.6.3 of this standard.
S5.1.6.2 This section applies to rear
passenger seats on school buses
manufactured on or after [compliance
date to be inserted] with a gross vehicle
weight rating less than or equal to 4,536
kg (10,000 pounds), equipped with Type
2 seat belt assemblies. When tested
under the conditions of S5.1.6.5.1
through 5.1.6.5.6, the school bus torso
belt anchor point must not displace
horizontally forward more than the
value in millimeters calculated from the
following expression:
(AH + 100) (tanF + 0.259/cosF) mm
where AH is the height in millimeters
of the school bus torso belt anchor point
defined by S4.1.3.2 of FMVSS No. 210
(49 CFR 571.210) and F is the angle of
the posterior surface of the seat back
defined in S5.1.6.3 of this standard.
S5.1.6.3 Angle of the posterior
surface of a seat back. Position the
loading bar specified in S6.5 of this
standard so that it is laterally centered
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behind the seat back with the bar’s
longitudinal axis in a transverse plane
of the vehicle in a horizontal plane
within ± 6 mm (0.25 inches) of the
horizontal plane passing through the
seating reference point and move the bar
forward against the seat back until a
force of 44 N (10 pounds) has been
applied. Position a second loading bar
as described in S6.5 of this standard so
that it is laterally centered behind the
seat back with the bar’s longitudinal
axis in a transverse plane of the vehicle
and in the horizontal plane 406 ± 6 mm
(16 ± 0.25 inches) above the seating
reference point, and move the bar
forward against the seat back until a
force of 44 N (10 pounds) has been
applied. Determine the angle from
vertical of a line in the longitudinal
vehicle plane that passes through the
geometric center of the cross-section of
each cylinder, as shown in Figure 8.
That angle is the angle of the posterior
surface of the seat back.
S5.1.6.4 The seat back must absorb
452W joules of energy when subjected
to the force specified in S5.1.6.5.7.
S5.1.6.5 Quasi-static test procedure.
S5.1.6.5.1 If the seat back inclination
is adjustable, the seat back is placed in
the manufacturer’s normal design riding
position. If such a position is not
specified, the seat back is positioned so
it is in the most upright position.
S5.1.6.5.2 Position the lower loading
bar specified in S6.5 of this standard so
that it is laterally centered behind the
seat back with the bar’s longitudinal
axis in a transverse plane of the vehicle
and in any horizontal plane between
102 mm (4 inches) above and 102 mm
(4 inches) below the seating reference
point of the school bus passenger seat
behind the test specimen. Position the
upper loading bar described in S6.5 so
that it is laterally centered behind the
seat back with the bar’s longitudinal
axis in a transverse plane of the vehicle
and in the horizontal plane 406 mm (16
inches) above the seating reference
point of the school bus passenger seat
behind the test specimen.
S5.1.6.5.3 Apply a force of 3,114W
N (700W pounds) horizontally in the
forward direction through the lower
loading bar specified at S6.5 at the pivot
attachment point. Reach the specified
load in not less than 5 and not more
than 30 seconds. No sooner than 1.0
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second after attaining the required force,
reduce that force to 1,557W N (350W
pounds) and maintain the pivot point
position of the loading bar at the
position where the 1,557W N (350W
pounds) is attained until the completion
of S5.1.6.5.5 and S5.1.6.5.6 of this
standard.
S5.1.6.5.4 Position the body block
specified in Figure 3 of FMVSS No. 210
(49 CFR 571.210) under each torso belt
(between the torso belt and the seat
back) in the passenger seat and apply a
preload force of 300 N (67 pounds) on
each body block in a forward direction
parallel to the longitudinal centerline of
the vehicle pursuant to the
specifications of FMVSS No. 210 (49
CFR 571.210). After preload application
is complete, the origin of the 203 mm
body block radius at any point across
the 102 mm body block thickness shall
lie within the zone defined by
S5.1.6.5.3(a) through S5.1.6.5.3(c):
(a) At or rearward of a transverse
vertical plane of the vehicle located 100
mm forward of the seating reference
point.
(b) At or above a horizontal plane
located 195 mm above the seating
reference point.
(c) At or below a horizontal plane
located 345 mm above the seating
reference point.
(d) Determination of the seating
reference point is provided by the
manufacturer; alternatively, if the
seating reference point is not provided
by the manufacturer, NHTSA will make
its own determination as to the seating
reference point.
S5.1.6.5.5 (a) For school buses with
a gross vehicle weight rating of 4,536 kg
(10,000 pounds) or less, simultaneously
apply the following force to each body
block:
(1) If ((seat bench width in
mm) ¥ (380Y)) is 25 mm (1 inch) or less,
apply 5,000 N (1,124 pounds); or
(2) If ((seat bench width in
mm) ¥ (380Y)) is greater than 25 mm (1
inch), apply 7,500 N (1,686 pounds).
(b) For school buses with a gross
vehicle weight rating of greater than
4,536 kg (10,000 pounds)
simultaneously apply the following
force to each body block:
(1) If ((seat bench width in
mm) ¥ (380Y)) is 25 mm (1 inch) or less,
apply 3,300 N (742 pounds); or
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(2) If ((seat bench width in
mm) ¥ (380Y)) is greater than 25 mm (1
inch), apply 5,000 N (1,124 pounds).
S5.1.6.5.6 Reach the specified load
in not less than 5 and not more than 30
seconds. Measure the torso belt anchor
point horizontal displacement and then
remove the body block.
S5.1.6.5.7 Apply an additional force
horizontally in the forward direction
through the upper bar until 452W joules
of energy have been absorbed in
deflecting the seat back. The maximum
travel of the pivot attachment point for
the upper loading bar shall not exceed
356 mm as measured from the position
at which the initial application of 44 N
of force is attained. Apply the additional
load in not less than 5 seconds and not
more than 30 seconds. Maintain the
pivot attachment point at the maximum
forward travel position for not less than
5 seconds, and not more than 10
seconds and release the load in not less
than 5 seconds and not more than 30
seconds. (For the determination of
S5.1.6.5.7, the energy calculation
describes only the force applied through
the upper loading bar, and the forward
and rearward travel distance of the
upper loading bar pivot attachment
point measured from the position at
which the initial application of 44 N of
force is attained.) If energy absorption of
452W joules cannot be obtained by the
seat back, the test procedure is
terminated and the seat back is
determined to have failed to meet
S5.1.6.4.
S5.1.7 Minimum seat width. For
school buses manufactured on or after
[compliance date to be inserted], each
passenger seating position with a Type
2 restraint system shall have a minimum
seating width and seat belt anchor
width of 380 mm (15 inches).
*
*
*
*
*
S5.2.2 Barrier height, position, and
rear surface area. The position and rear
surface area of the restraining barrier
shall be such that, in a front projected
view of the bus, each point of the
barrier’s perimeter coincides with or lies
outside of the perimeter of the
minimum seat back area required by
S5.1.2 for the seat immediately rearward
of the restraining barrier.
*
*
*
*
*
E:\FR\FM\21NOP1.SGM
21NOP1
65532
Federal Register / Vol. 72, No. 224 / Wednesday, November 21, 2007 / Proposed Rules
BILLING CODE 4910–59–P
DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety
Administration
49 CFR Part 594
[Docket No. NHTSA 2007–0037; Notice 1]
mstockstill on PROD1PC66 with PROPOSALS
RIN 2127–AK10
Schedule of Fees Authorized by 49
U.S.C. 30141 Offer of Cash Deposits or
Obligations of the United States in Lieu
of Sureties on DOT Conformance
Bonds
National Highway Traffic
Safety Administration (NHTSA), DOT.
AGENCY:
VerDate Aug<31>2005
16:47 Nov 20, 2007
Jkt 214001
Notice of proposed rulemaking
(NPRM).
ACTION:
SUMMARY: This document proposes to
amend NHTSA’s regulations that
prescribe fees authorized by 49 U.S.C.
Sec. 30141 for various functions
performed by the agency with respect to
the importation of motor vehicles that
do not conform to all applicable Federal
motor vehicle safety and bumper
standards. An importer must file with
U.S. Customs and Border Protection
(CBP) a Department of Transportation
(DOT) conformance bond at the time
that a nonconforming motor vehicle is
offered for importation into the United
States, or in lieu of such a bond, the
importer may post cash deposits or
obligations of the United States to
ensure that the vehicle will be brought
into conformance with all applicable
standards within 120 days from the date
of importation, or will be exported from,
or abandoned to, the United States. To
avoid the costs of a DOT conformance
bond, some importers have sought to
PO 00000
Frm 00063
Fmt 4702
Sfmt 4702
post cash deposits, which would relieve
the importers of the bonding costs but
cause the agency to expend considerable
resources. To permit the government to
recover these expenses, this amendment
would establish a fee for the agency’s
processing of these cash deposits or
obligations of the United States that are
furnished in lieu of a DOT conformance
bond.
You should submit your
comments early enough to ensure that
Docket Management receives them not
later than January 7, 2008.
DATES:
Comments should refer to
the docket and notice numbers above
and be submitted by any of the
following methods:
• Federal eRulemaking Portal: Go to
https://www.regulations.gov. Follow the
online instructions for submitting
comments.
• Mail: Docket Management Facility:
U.S. Department of Transportation, 1200
New Jersey Avenue, SE., West Building
ADDRESSES:
E:\FR\FM\21NOP1.SGM
21NOP1
EP21NO07.004
Issued on: November 15, 2007.
Ronald L. Medford,
Senior Associate Administrator for Vehicle
Safety.
[FR Doc. 07–5758 Filed 11–19–07; 10:00 am]
Agencies
[Federal Register Volume 72, Number 224 (Wednesday, November 21, 2007)]
[Proposed Rules]
[Pages 65509-65532]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 07-5758]
[[Page 65509]]
=======================================================================
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
[Docket No. NHTSA-2007-0014]
RIN 2127-AK09
Federal Motor Vehicle Safety Standards; Seating Systems, Occupant
Crash Protection, Seat Belt Assembly Anchorages, School Bus Passenger
Seating and Crash Protection
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation (DOT).
ACTION: Notice of proposed rulemaking (NPRM).
-----------------------------------------------------------------------
SUMMARY: NHTSA issued a report in 2002 on the results of a
comprehensive school bus research program examining ways of further
improving school bus safety. Based on that research, we are now
proposing several upgrades to the school bus passenger crash protection
requirements.
For new school buses of 4,536 kilograms (10,000 pounds) or less
gross vehicle weight rating (GVWR), we propose to require lap/shoulder
belts in lieu of the lap belts that are currently specified. For school
buses with gross vehicle weight ratings (GVWR) greater than 4,536
kilograms (kg) (10,000 pounds), this NPRM provides guidance to State
and local jurisdictions on the subject of installing seat belts. Each
State or local jurisdiction would continue to decide whether to install
belts on these large school buses. Where State or local decisions are
made to install lap or lap/shoulder belts on large school buses, this
NPRM proposes performance requirements for those voluntarily-installed
seat belts on large school buses manufactured after the proposed
effective date.
Other changes to school bus safety requirements are also proposed,
including raising the height of seat backs from 20 inches to 24 inches
on all new school buses.
DATES: Comments must be received on or before January 22, 2008.
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 https://
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: (202) 493-2251.
Regardless of how you submit your comments, you should mention the
docket number of this document.
You may call the Docket at 202-366-9324.
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 https://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 non-legal issues, Mr. Charles
Hott, Office of Vehicle Safety Standards (telephone: 202-366-0247)
(fax: 202-366-4921). Mr. Hott's mailing address is National Highway
Traffic Safety Administration, NVS-113, 1200 New Jersey Avenue, SE.,
Washington, DC 20590.
For legal issues, Ms. Dorothy Nakama, Office of the Chief Counsel
(telephone: 202-366-2992) (fax: 202-366-3820). Ms. Nakama's mailing
address is National Highway Traffic Safety Administration, NCC-112,
1200 New Jersey Avenue, SE., Washington, DC 20590.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Introduction
II. Background
III. The Issue of Seat Belts on Large School Buses
IV. Studies
V. Federal Guidance on Belts on Large Buses
a. NHTSA School Bus Research Results
b. Agency Recommended Best Practices
c. Guidance on Lap Belts on Large School Buses
VI. Proposed Upgrades to Occupant Crash Protection
a. Improving the Compartmentalized School Bus Interior of Both
Small and Large School Buses
b. Additional Occupant Protection Requirements for Small School
Buses (School Buses With a GVWR of 4,536 kg (10,000 lb) or Less)
c. Additional Occupant Protection Requirements for Large School
Buses With Voluntarily-Installed Lap/Shoulder Seat Belts
d. Additional Requirements for Large School Buses with
Voluntarily-Installed Lap Belts
VII. Quasi-Static Test for Lap/Shoulder Belts on Small and Large
School Buses
a. Stage 1: Torso Belt Anchorage Displacement
b. Stage 2: Energy Absorption Capability of the Seat Back
c. Request for Comments
VIII. Lead Time
IX. Rulemaking Analyses and Notices
X. Public Participation
Appendix A to the Preamble--Proposed Amendments to Federal Motor
Vehicle Safety Standards
I. Introduction
This document proposes to upgrade the school bus occupant
protection requirements of the Federal motor vehicle safety standards,
primarily by amendments to Federal Motor Vehicle Safety Standard No.
(FMVSS) No. 222, ``School bus passenger seating and crash protection''
(49 CFR 571.222), and by amendments to FMVSS Nos. 207, 208, and 210. It
also provides guidance to state and local jurisdictions on the subject
of installing seat belts on large school buses (school buses with a
GVWR greater than 4,536 kilograms (kg) (10,000 pounds (lb)) and asks
for comments on the agency's consideration of ``best practices''
concerning the belts on the large buses.\1\
---------------------------------------------------------------------------
\1\ ``School bus'' is defined in 49 CFR Sec. 571.3 as a bus
that is sold, or introduced in interstate commerce, for purposes
that include carrying students to and from school or related events,
but does not include a bus designed and sold for operation as a
common carrier in urban transportation. A ``bus'' is a motor
vehicle, except a trailer, designed for carrying more than 10
persons. In this NPRM, when we refer to ``large'' school buses, we
refer to those school buses with GVWRs of more than 4,536 kg (10,000
lb). These large school buses may transport as many as 90 students.
``Small'' school buses are school buses with a GVWR of 4,536 kg
(10,000 lb) or less. Generally, these small school buses seat 15
persons or fewer, or have one or two wheelchair seating positions.
---------------------------------------------------------------------------
This NPRM's most significant proposed changes to FMVSS No. 222
involve:
Increasing the minimum seat back height requirement from
20 inches from the seat's seating reference point (SgRP) to 24 inches
for all school buses;
Requiring small school buses to have a lap/shoulder belt
at each passenger seating position (the buses are currently required to
have lap belts);
Incorporating test procedures into the standard to test
lap/shoulder belts in small school buses and voluntarily-installed lap/
shoulder belts in large school buses to ensure both the strength of the
anchorages and the compatibility of the seat with compartmentalization;
and,
Requiring all school buses with seat bottom cushions that
are designed to flip-up, typically for easy cleaning, to have a self-
latching mechanism.
[[Page 65510]]
The proposed guidance to state and local jurisdictions on best
practices of installing seat belts on large school buses acknowledges
that, in terms of the optimum passenger crash protection that can be
afforded an individual passenger on a large school bus, a lap/shoulder
belt system, together with compartmentalization, would afford that
optimum protection. Thus, we encourage providers to consider lap/
shoulder belts on large school buses. However, installing current lap/
shoulder belts on large school buses would reduce the passenger
carrying capacity of large buses. If children were diverted to other
means of transport to school, such as transport by smaller, private
vehicles, walking, or biking, the belts on the buses could result in an
overall disbenefit to pupil transportation safety due to the children
displaced from the large school buses having to find less safe modes of
transportation to get to or from school or related events. Thus, we are
not proposing to require lap/shoulder belts on large school buses, and
we recommend providers to ascertain whether installing lap/shoulder
belts would reduce the number of children that are transported to
school on large school buses.
II. Background
The Motor Vehicle and Schoolbus Safety Amendments of 1974 directed
NHTSA to issue motor vehicle safety standards applicable to school
buses and school bus equipment. In response to this legislation, NHTSA
revised several of its safety standards to improve existing
requirements for school buses, extended ones for other vehicle classes
to those buses, and issued new safety standards exclusively for school
buses. FMVSS No. 222, one of a set of new standards for school buses,
improves protection to school bus passengers during crashes and sudden
driving maneuvers.
Effective since 1977, FMVSS No. 222 contains occupant protection
requirements for school bus seating positions and restraining barriers.
Its requirements for school buses with GVWR's of 4,536 kg (10,000 lb)
or less differ from those set for school buses with GVWR's greater than
4,536 kg (10,000 lb), because the ``crash pulse'' or deceleration
experienced by the small school buses is more severe than that of the
large buses in similar collisions. For the small school buses, the
standard includes requirements that all seating positions must be
equipped with properly installed lap or lap/shoulder seat belt
assemblies and anchorages for passengers.\2\ NHTSA decided that seat
belts were necessary on small school buses to provide adequate crash
protection for the occupants. For the large school buses, FMVSS No. 222
relies on requirements for ``compartmentalization'' to provide
passenger crash protection. Investigations of school bus crashes prior
to issuance of FMVSS No. 222 found the school bus seat was a
significant factor in causing injury. NHTSA found that the seat failed
the passengers in three principal respects: by being too weak, too low,
and too hostile (39 FR 27584; July 30, 1974). In response to this
finding, NHTSA developed a set of requirements which comprise the
``compartmentalization'' approach.
---------------------------------------------------------------------------
\2\ Lap/shoulder belts and appropriate anchorages for the driver
and front passenger (if provided) seating position, lap belts and
appropriate anchorages for all other passenger seating positions.
---------------------------------------------------------------------------
Compartmentalization ensures that passengers are cushioned and
contained by the seats in the event of a school bus crash by requiring
school bus seats to be positioned in a manner that provides a compact,
protected area surrounding each seat. If a seat is not
compartmentalized by a seat back in front of it, compartmentalization
must be provided by a padded and protective restraining barrier. The
seats and restraining barriers must be strong enough to maintain their
integrity in a crash yet flexible enough to be capable of deflecting in
a manner which absorbs the energy of the occupant. They must meet
specified height requirements and be constructed, by use of substantial
padding or other means, so that they provide protection when they are
impacted by the head and legs of a passenger. Compartmentalization
minimizes the hostility of the crash environment and limits the range
of movement of an occupant. The compartmentalization approach ensures
that high levels of crash protection are provided to each passenger
independent of any action on the part of the occupant.
III. The Issue of Seat Belts on Large School Buses
NHTSA has considered the question of whether seat belts should be
required on large school buses from the inception of
compartmentalization and the school bus safety standards. NHTSA has
been repeatedly asked to require belts on buses, and has repeatedly
concluded that compartmentalization provides a high level of safety
protection that obviates the safety need for a Federal requirement
necessitating the installation of seat belts. Further, the agency has
been acutely aware that a decision on requiring seat belts in large
school buses cannot ignore the implications of such a requirement on
pupil transportation costs. The agency has been attentive to the fact
that, as a result of requiring belts on large school buses, school bus
purchasers would have to buy belt-equipped vehicles regardless of
whether seat belts would be appropriate for their needs. NHTSA has
concluded that those costs should not be imposed on all purchasers of
school buses when large school buses are currently very safe. In the
area of school transportation especially, where a number of needs are
competing for limited funds, persons responsible for school
transportation might want to consider other alternative investments to
improve their pupil transportation programs which can be more effective
at reducing fatalities and injuries than seat belts on large school
buses, such as by acquiring additional new school buses to add to their
fleet, or implementing improved pupil pedestrian and driver education
programs. Since each of these efforts competes for limited funds, the
agency has maintained that those administrators should decide how their
funds should be allocated.
IV. Studies
Nonetheless, throughout the past 30 years that compartmentalization
and the school bus safety standards have been in effect, the agency has
openly and continuously considered the merits of a seat belt
requirement for large school buses.\3\ The issue has been closely
analyzed by other parties as well, such as the National Transportation
Safety Board, and the National Academy of Sciences. Various reports
have been issued, the most significant of which are described below.
---------------------------------------------------------------------------
\3\ Through the years, NHTSA has been petitioned about seat
belts on large school buses. (See, e.g., denials of petitions to
require seat belt anchorages, 41 FR 28506 (July 12, 1976), 48 FR
47032 (October 17, 1983); response to petition for rulemaking to
prohibit the installation of lap belts on large school buses, 71 FR
40057 (July 14, 2006).) In a letter dated February 16, 2007, the
National Association of Pupil Transportation (NAPT) petitioned the
agency ``to initiate rulemaking on occupant protection in school
buses.'' NAPT said that it did not support the installation of lap
belts in large school buses, nor the installation of lap/shoulder
belts. NAPT stated it ``will only support changes to
compartmentalization when we are sure that those changes will not
compromise student safety in any way.'' NAPT requested that the
agency review FMVSS No. 222, ``with the goal of establishing a
safety system that will definitively enhance the current passenger
crash protection for all children that ride a school bus.'' NAPT
also advocated a public education program emphasizing the importance
of safe school bus transportation.
---------------------------------------------------------------------------
[[Page 65511]]
Studies
National Transportation Safety Board, 1987
In 1987, the National Transportation Safety Board (NTSB) reported
on a study of forty-three post-standard school bus crashes investigated
by the Safety Board. NTSB concluded that most fatalities and injuries
in school bus crashes occurred because the occupant seating positions
were directly in line with the crash forces, and that seat belts would
not have prevented those injuries and fatalities. (NTSB/SS-87/01,
Safety Study, Crashworthiness of Large Post-standard School Buses,
March 1987, National Transportation Safety Board.)
National Academy of Sciences, 1989
A 1989 National Academy of Sciences (NAS) study concluded that the
overall potential benefits of requiring seat belts on large school
buses were insufficient to justify a Federal mandate for installation.
The NAS also stated that funds used to purchase and maintain seat belts
might be better spent on other school bus safety programs with the
potential to save more lives and reduce more injuries. (Special Report
222, Improving School Bus Safety, National Academy of Sciences,
Transportation Research Board, Washington, DC, 1989.)
National Transportation Safety Board, 1999
In 1999, NTSB reported on six school bus crashes it investigated in
which passenger fatalities or serious injuries occurred away from the
area of vehicle impact. NTSB found compartmentalization to be an
effective means of protecting passengers in school bus crashes.
However, because many of those passengers injured in the six crashes
were believed to have been thrown from their compartments, NTSB
believed other means of occupant protection should be examined. (NTSB/
SIR-99/04, Highway Safety Report, Bus Crashworthiness Issues, September
1999, National Transportation Safety Board.)
National Academy of Science, 2002
In 2002, NAS published a study that analyzed the safety of various
transportation modes used by school children to get to and from school
and school-related activities. The report concluded that each year
there are approximately 815 school transportation fatal injuries per
year. Two percent were school bus-related, compared to 22 percent due
to walking/bicycling, and 75 percent from passenger car crashes,
especially those with teen drivers. The report stated that changes in
any one characteristic of school travel can lead to dramatic changes in
the overall risk to the student population. Thus, NAS concluded, it is
important for school transportation decisions to take into account all
potential aspects of changes to requirements to school transportation.
(Special Report 269, ``The Relative Risks of School Travel: A National
Perspective and Guidance for Local Community Risk Assessment,''
Transportation Research Board of the National Academies, 2002.)
National Highway Traffic Safety Administration, 2002
In 2002, NHTSA issued a Congressional Report that detailed occupant
safety on school buses and analyzed options for improving occupant
safety. NHTSA concluded that compartmentalization effectively lowered
injury measures by distributing crash forces with the padded seating
surface. Lap belts showed little to no benefit in reducing serious/
fatal injuries. The agency determined that properly used combination
lap and shoulder belts have the potential to be effective in reducing
fatalities and injuries for not only frontal collisions, but also
rollover crashes where belt systems are particularly effective in
reducing ejection. However, the addition of lap/shoulder belts on buses
would increase capital costs and reduce seating capacity on the buses.
(``Report to Congress, School Bus Safety: Crashworthiness Research,
April 2002,'' https://www-nrd.nhtsa.dot.gov/departments/nrd-11/
SchoolBus/SBReportFINAL.pdf.)
V. Federal Guidance on Belts on Large Buses
This document provides guidance to state and local jurisdictions on
the subject of installing seat belts on large school buses and asks for
comments on the agency's consideration of ``best practices'' concerning
the belts on the large buses.
This guidance is provided in response to the information that the
agency received at its July 11, 2007 public meeting in Washington, DC
on seat belts on school buses (notice of public meeting, 72 FR 30739,
June 4, 2007, Docket 28103).\4\ In this meeting, NHTSA brought together
a roundtable of State and local government policymakers, school bus and
seat manufacturers, pupil transportation associations, and consumer
groups to address: State and local policy perspectives regarding
whether to require seat belts on school buses; information on the type
of seat belt system designs that are currently being offered on large
school buses; the economic impact that implementation of seat belt
requirements for school buses (including purchase and maintenance of
belts) have on States and local school districts; and the experience of
schools and States in training and educating children, parents and
drivers to use seat belts on large school buses.\5\ At the meeting,
participants requested that NHTSA provide up-to-date Federal guidance
on whether seat belts should be provided on school buses, and whether
lap belts should or should not be installed.
---------------------------------------------------------------------------
\4\ NHTSA also received written comments to docket 28103. We
will address all relevant issues raised in those comments in today's
NPRM and in a final rule or other rulemaking document following
today's NPRM.
\5\ A transcript of the July 11, 2007 public meeting is
available in docket 28103.
---------------------------------------------------------------------------
The agency has considered all of the comments made at the meeting.
NHTSA found the following views particularly helpful:
Mr. Charles Hood of the Florida Department of Education
related the State of Florida's experience with lap belts on school
buses. Informally, Mr. Hood estimated that the lap belt usage rate in
Florida was about 70 percent for elementary school students, 35 percent
for middle school students, and 25 percent for high school students.
Mr. Hood reported that vandalism and maintenance of the seat belts were
not major concerns. Mr. Hood estimated that the annual charge to equip
all of Florida's 1399 school buses with lap/shoulder belts would be
about $14 million.
Mr. Hood believed that the key point of the debate is
whether the three point belts will: Improve overall safety through the
crash protection improvements that they provide, or reduce overall
safety by potentially reducing the number of children who ride in
school buses. Mr. Hood stated that States that require lap belts need
Federal guidance as to whether they may or should continue to specify
lap belts in their school buses.
Ms. Ann Roy Moore of the Huntsville, Alabama City Schools
recommended that national agencies come up with some standards that
could be used to address the issue of school bus safety generally and
seat belt safety in particular.
Mr. Ken Hedgecock of Thomas Built Buses stated that two-
point belts are on 27 percent of the school buses Thomas Built
manufactures, and three-point belts are on 2 percent the school buses
that it manufactures. Mr. Hedgecock said that the greatest concern
relating to seat belts pertains to capacity and cost issues of the
three-point belt system. The reduction in capacity and incremental
costs of the three-point
[[Page 65512]]
system may have the unintended consequence of transporting fewer
children on the yellow school bus, thus negatively affecting the safety
of our nation's children. Mr. Hedgecock recommended the following as it
pertains to seat belts: Clarification is needed on the use of two-point
belt systems versus three-point belt systems in school buses;
clarification is needed on the designated seating position as it
pertains to a seat with seat belts; and there is a need for clear
performance standards for the integration of all systems: the school
bus, the seat, and the belts.
Mr. Steve Wallen of Safeguard, a division of Indiana Mills
Manufacturing Inc. (IMMI), stated that its testing shows that
compartmentalization does well in front and rear impact crashes, but
not particularly well in rollovers. Mr. Wallen recommends the FMVSSs
should be amended so as to allow for lap/shoulder belts while
maintaining compartmentalization to protect unbelted occupants. Mr.
Wallen suggested that the FMVSSs specify requirements such that a
school bus seat can withstand a crash with a student wearing a seat
belt and one behind not wearing a seat belt at the same time. Mr.
Wallen noted that retrofitting school buses is substantially more
expensive and difficult than installing seats in new buses.
Ms. Robin Leeds of the National School Transportation
Association (NSTA) stated that a Federal mandate is not appropriate
because of the costs. NSTA believes States and local school districts
are in a better position to determine the best use of their resources
than the Federal government. In the NSTA's view, the only way any
safety belt program can be successful is if it has the full commitment
of the school administration and of parents to make them work. NSTA
also recommended that NHTSA develop standards for voluntarily-installed
lap/shoulder belt systems so that ``everybody knows what system to use
when they do install those systems.''
a. NHTSA School Bus Research Results
Our guidance about seat belts on school buses also takes into
account the agency's research findings assessing the efficacy of
existing safety measures employed on school buses and possible
improvements to school bus occupant protection.
The Transportation Equity Act for the 21st Century (TEA-21)
directed NHTSA to study and assess school bus occupant safety and
analyze options for improvement. In response, the agency developed a
research program to determine the real-world effectiveness of FMVSS No.
222 requirements for school bus passenger crash protection, evaluate
alternative passenger crash protection systems in controlled laboratory
tests, and provide findings to support rulemaking activities to upgrade
the passenger crash protection for school bus passengers.
The research program consisted of NHTSA first conducting a full-
scale school bus crash test to determine a representative crash pulse.
The crash test was conducted by frontally impacting a conventional
style school bus (Type C) into a rigid barrier at 30 mph (48.3 km/h).
The impact speed was chosen to ensure that sufficient energy would be
imparted to the occupants in order to evaluate the protective
capability of compartmentalization, plus provide a level at which other
methods for occupant injury mitigation could be evaluated during sled
testing. A 30 mph (48 km/h) impact into the rigid barrier is also
equivalent to two vehicles of similar size impacting at a closing speed
of approximately 60 mph (96 km/h), which was found to be prevalent in
the crash database files.
In the crash test, we used Hybrid III 50th percentile adult male
dummies (representing adult and large teenage occupants), 5th
percentile adult female (representing an average 12-year-old (12YO)
occupant), and a 6-year-old child dummy (representing an average 6-
year-old (6YO) occupant). The dummies were seated so that they were as
upright as possible and as rearmost on the seat cushion as possible.
The agency evaluated the risk of head injury recorded by the dummies
(Head Injury Criterion (HIC15)), as well as the risk of chest (chest
G's) and neck injury (Nij),\6\ as specified in FMVSS No. 208 ``Occupant
crash protection.''
---------------------------------------------------------------------------
\6\ HIC15, Chest G, and Nij values are used to predict injury
risk in frontal crashes. HIC15 is a measure of the risk of head
injury, Chest G is a measure of chest injury risk, and Nij is a
measure of neck injury risk. The reference values for these
measurements are the thresholds for compliance used to assess new
motor vehicles with regard to frontal occupant protection during
crash tests, FMVSS No. 208. For HIC15, a score of 700 is equivalent
to a 30 percent risk of a serious head injury (skull fracture and
concussion onset). In a similar fashion, Chest G of 60 equates to a
20 percent risk of a serious chest injury and Nij of 1 equates to a
22 percent risk of a serious neck injury. For all these
measurements, higher scores indicate a higher likelihood of risk.
For example, a Nij of 2 equates to a 67 percent risk of serious neck
injury while a Nij of 4 equates to a 99 percent risk. More
information regarding these injury measures can be found at NHTSA's
Web site (https://www-nrd.nhtsa.dot.gov/pdf/nrd-11/airbags/rev_
criteria.pdf).
---------------------------------------------------------------------------
NHTSA then ran frontal crash test simulations at the agency's
Vehicle Research and Test Center (VRTC), using a test sled to evaluate
passenger protection systems. Twenty-five sled tests using 96 test
dummies of various sizes utilizing different restraint strategies were
conducted that replicated the acceleration time history of the school
bus full-scale frontal impact test. The goal of the laboratory tests
was to analyze the dummy injury measures to gain a better understanding
of the effectiveness of the occupant crash protection countermeasures.
In addition to injury measures, dummy kinematics and interaction with
restraints (i.e., seat backs and seat belts, as well as each other)
were also analyzed to provide a fuller picture of the important factors
contributing to the type, mechanism, and potential severity of any
resulting injury.
NHTSA studied three different restraint strategies: (a)
compartmentalization; (b) lap belt (with compartmentalization); and,
(c) fore/aft loading.\7\
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\7\ Unbelted occupants in the aft seat will affect the
kinematics of belted occupants in the fore seat due to seat back
deformation. Similarly, belted occupant loading of the fore seat
back thru the torso belt will affect the compartmentalization for
unbelted occupants in the aft seat.
---------------------------------------------------------------------------
Within the context of these restraint strategies, various boundary
conditions were evaluated: (a) Seat spacing--483 mm (19 inches), 559 mm
(22 inches) and 610 mm (24 inches); (b) seat back height--nominally 508
mm (20 inches) and 610 mm (24 inches); and, (c) fore/aft seat occupant
loading. Ten dummies were tested with misused or out-of-position (OOP)
lap or shoulder restraints. The restraints were misused by placing the
lap belt too high up on the waist, placing the lap/shoulder belt placed
behind the dummy's back, or placing the lap/shoulder belt under the
dummy's arm.
The agency found the following with regard to compartmentalization:
Low head injury values were observed for all dummy sizes,
except when override \8\ occurred.
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\8\ Override means an occupant's head or torso translates
forward beyond the forward seat back providing compartmentalization.
---------------------------------------------------------------------------
High head injury values or dummy-to-dummy contacts beyond
the biofidelic range of the test dummy were produced when the large
male dummy overrode the seat in front of it, while the high-back seats
prevented this.
Low chest injury values were observed for all dummy sizes.
Based on dummy motion and interaction with each other,
compartmentalization was sensitive to seat back height for the 50th
percentile male dummy.
Compartmentalization of 6YO and 5th percentile female
dummies did not
[[Page 65513]]
appear to be sensitive to rear loading conditions.
Compartmentalization of the 50th percentile male dummy did
not appear to be sensitive to seat spacing for the 50th percentile male
dummy.
The agency found the following with regard to lap belts on large
school buses:
Head and chest injury values were low for all dummy sizes.
The average neck injury value was above the injury
assessment reference value (IARV) for all test dummies, and was 70
percent above for the 5th percentile female dummy.
Neck injury values increased for the 5th percentile female
dummy when the seat spacing was increased from 483 mm (19 inches) to
559 mm (22 inches).
The agency found the following with regard to properly worn lap/
shoulder belts on school buses:
Head, chest and neck injury values were low for all size
dummies and below those seen in the compartmentalization and lap belt
results.
Average head injury values were, at most, about half those
seen in the compartmentalization and lap belt results.
Neck injury values increased with application of rear
loading for the 6YO and 5th percentile female dummies.
Lap/shoulder belt systems would require approximately 15
inches seat width per passenger seating position. The standard school
bus bench seat is 39 inches wide, and is considered a three-passenger
seat. If the width of the seat bench were increased to 45 inches for
both seats on the left and right side of the school bus, the aisle
width would be reduced to an unacceptable level.
NHTSA found that, for improperly worn lap/shoulder belts:
Placing the shoulder belt behind the dummy's back resulted
in dummy motion and average dummy injury values similar to lap belt
restraint.
Placing the shoulder belt under the dummy's arm provided
more restraint on dummy torso motions than when the belt is placed
behind the back. Average dummy injury values for the 6YO were about the
same as seen with lap/shoulder belts and 5th percentile female dummy
injury values were between those seen in lap/shoulder belts and lap
belts.
b. Agency Recommended Best Practices
School buses are one of the safest forms of transportation in the
U.S. Every year, approximately 474,000 public school buses,
transporting 25.1 million children to and from school and school-
related activities,\9\ travel an estimated 4.8 billion route miles.\10\
Over the 11 years ending in 2005, there was an annual average of 26
school transportation related fatalities (11 school bus occupants
(including drivers and passengers) and 15 pedestrians).\11\ The bus
occupant fatalities were comprised of six school-age children, with the
remaining being adult drivers and passengers.\12\ On average, there
were 9 crashes per year in which an occupant was killed. The school bus
occupant fatality rate of 0.23 fatalities per 100 million vehicle miles
traveled (VMT) is more than six times lower than the overall rate for
motor vehicles of 1.5 per 100 million VMT.\13\
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\9\ School Transportation News, Buyers Guide 2007.
\10\ This value was reported by School Bus Fleet 2007 Fact Book.
\11\ ``Traffic Safety Facts--School Transportation Related
Crashes,'' NHTSA, DOT HS 810 626. The data in this publication
account for all school transportation-related deaths in transporting
students to and from school and school related activities. This
includes non-school buses used for this purpose when these vehicles
are involved in a fatal crash.
\12\ For the crashes resulting in the 11 annual school bus
occupant fatalities, 51 percent of the fatalities and 52 percent of
the crashes were from frontal collisions. Traffic Safety Facts 2005,
School Transportation-Related Crashes, DOT HS 810 626.
\13\ Traffic Safety Facts 2005, DOT HS 810 631.
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The agency's school bus research results indicated that lap/
shoulder belts could enhance the safety of large school buses, such
that a child who has a seat on the school bus and who is belted with a
lap/shoulder belt on the bus would have an even lower risk of head and
neck injury than on current large school buses.\14\ Thus, if ample
funds were available for pupil transportation, and pupil transportation
providers could order and purchase a sufficient number of school buses
needed to provide school bus transportation to all children, we would
recommend that pupil transportation providers consider installing lap/
shoulder belts on large school buses because of the enhancements that
lap/shoulder belts could make to school buses. Realistically, however,
we recognize that funds provided for pupil transportation are limited,
and that the monies spent on lap/shoulder belts on large school buses
would usually draw from the monies spent on other crucial aspects of
school transportation, such as purchasing new school buses to ensure
that as many children as possible are provided school bus
transportation, on driver and pupil training on safe transportation
practices, and on upkeep and maintenance of school buses and school bus
equipment. Bearing these considerations in mind, we recommend that
pupil transportation providers consider lap/shoulder belts on large
school buses only if there would be no reduction in the number of
children that are transported to or from school or related events on
large school buses. Reducing bus ridership would likely result in more
student fatalities, since walking and private vehicles are less safe
than riding a large school bus without seat belts.
---------------------------------------------------------------------------
\14\ The TEA-21 research program did not study whether belts
could enhance the protection of compartmentalization in side crashes
and rollovers. Most school bus fatalities occur in a crash involving
a rollover, and the side crash fatalities are about as frequent as
front crash fatalities.
---------------------------------------------------------------------------
Our best practices recommendation seeks to reflect real world
considerations about the safety record of school buses, the economic
impact on school systems incurred by the costs of seat belts and the
impact that lap/shoulder belts have on the seating capacity of large
school buses. Our laboratory test results indicate that our test
dummies measured better head protection performance when lap/shoulder
belts were properly used with compartmentalization than compared to
compartmentalization alone. However, best practices compel us to
acknowledge that installation of lap/shoulder belts, as currently
designed, reduce the number of seats offered to students, resulting in
fewer children riding school buses, exposing more children to higher
safety risks in alternative forms of transport to or from school or
related events, and a probable overall net safety disbenefit due to
their installation.
Best practices compel us to encourage pupil transportation
providers to make a comprehensive analysis of their needs and determine
how lap/shoulder belts on large school buses accord with those needs.
The best practices approach we have developed allows States the leeway
to decide whether to require seat belts on large school buses, and
whether lap only or lap/shoulder belts should be ordered. Given the
tradeoff noted above, States should be permitted the flexibility of
deciding whether to order large school buses with the seat belt safety
enhancements after considering the excellent safety record of large
school buses with compartmentalization, the benefits of allocating
resources to belts as opposed to alternative safety measures, and the
means available to ensure that the belts would be used. If a State were
to determine that lap/shoulder belts are in its best interest, NHTSA
encourages the State to install those systems. Today's document
proposes performance requirements for the lap/shoulder belts, to ensure
they will work well in a crash even if voluntarily installed.
[[Page 65514]]
Certain highway safety grant funds may continue to be used to fund
the purchase and installation of seat belts (lap or lap/shoulder) on
school buses. Annually, all States, the District of Columbia, Puerto
Rico, the Bureau of Indian Affairs, and the U.S. territories receive
NHTSA Section 402 State and Community Highway Safety Formula Grant
Funds. A wide range of behavioral highway safety activities that help
reduce crashes, deaths, and injuries, including seat belt-related
activities, qualify as eligible costs under the Section 402 program.
Each State determines how to allocate its funds based on its own
priorities and identified highway safety problems as described in an
annual Highway Safety Plan (HSP).
As with all proposed expenditures of Section 402 funds, the
purchase and installation of seat belts on school buses must be
identified as a need in the State's HSP and comply with all
requirements under 23 U.S.C. Part 1200. Section 402 funds may not be
used to purchase the school bus in its entirety, but may fund only the
incremental portion of the bus cost directly related to the purchase
and installation of seat belts.
We would advise States that are considering purchasing seat belts
for school buses to be guided by the proposed standards in this notice
of proposed rulemaking.
c. Guidance on Lap Belts on Large School Buses
In the July 11, 2007 public meeting, some participants asked for
guidance on whether lap belts should be prohibited on large school
buses. The question was asked in the aftermath of school bus research
studies that found lap belts were associated with increased risk of
injury on large school buses.\15\
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\15\ See the results of NHTSA's school bus research program
(Report to Congress, School Bus Safety: Crashworthiness Research,
supra). In addition, a 1985 study by Transport Canada provided data
comparing the reaction of three belted and three unbelted 5th
percentile adult female anthropomorphic test dummies in a 48 km/h
(30 mph) frontal collision of a large school bus meeting
compartmentalization requirements. The results indicated that the
belted dummies experienced higher head accelerations, lower chest
accelerations and more severe neck extension than did the unbelted
ones. Accordingly, the study concluded that the use of a lap belt
system in a school bus ``may result in more severe head and neck
injuries for a belted occupant than an unbelted one, in a severe
frontal collision.'' (School Bus Safety Study, January 1985). After
analyzing the Transport Canada study, NHTSA could not conclude from
the report's findings that belts degraded the benefits of
compartmentalization to the extent that the supplemental restraint
system rendered inoperative the safety of large school buses, but
NHTSA acknowledged that the possibility exists that the occupant
kinematics shown in the Canadian tests could occur. (Docket No. 85-
14; Notice 02, RIN 2127-AB84, March 22, 1989).
---------------------------------------------------------------------------
After considering the data and other information on lap belts on
large school buses, NHTSA does not believe there is a need to prohibit
lap belts on the buses. In its 1999 report on bus crashworthiness, the
NTSB concluded that the compartmentalization requirement for school
buses in FMVSS No. 222 is incomplete in addressing school bus occupant
protection in rollovers and lateral impacts from large vehicles, in
that in such crashes, passengers do not always remain completely within
the seating compartment. Although we have not found a safety need
exists with respect to those non-frontal crashes to warrant requiring
seat belts on large school buses,\16\ we have always permitted States
to choose to require the belts over and above the Federally required
compartmentalization in the school buses they purchase.
---------------------------------------------------------------------------
\16\ We reiterate our conclusion that the overall potential
benefits of requiring lap belts on large school buses are
insufficient to justify a Federal requirement for mandatory
installation. NAS has also suggested that the funds used for
required seat belts might be better used in other school bus safety
programs. Special Report 222 (1989), supra.
---------------------------------------------------------------------------
We realize that laboratory research, including our own on lap
belted dummies, shows relatively poor performance of lap belts in large
school buses. However, this research involved severe frontal impacts.
We cannot make a determination, based on the results of the limited
testing with lap belt restraints in a severe frontal crash condition,
that the addition of lap belts in large school buses reduces overall
occupant protection. Lap belts are required in three States (New York
(1987), New Jersey (1994), Florida (2001)), in many other school
districts, and in special-needs equipped school buses. NHTSA has
examined in depth New York State school bus crash data for lap belt
equipped and non-belt equipped buses, and could not conclude that lap
belts either helped or hurt occupant injury outcomes.
VI. Proposed Upgrades to Occupant Crash Protection
After considering the findings of NHTSA's school bus research
program, we have decided to issue this NPRM to propose several sets of
upgrades to the school bus safety requirements. The first set of
upgrades involves improving the compartmentalized school bus interior
on both small and large school buses. Seat back height would be
increased from 20 inches to 24 inches to reduce the potential for
passenger override in a crash, and school buses with seat bottom
cushions that are designed to flip-up, typically for easy cleaning,
would need a self-latching mechanism. The proposal to raise seat back
height responds to findings from the agency's school bus research
program, while the proposal for self-latching mechanisms responds to an
NTSB recommendation to NHTSA (H-84-75).
The second set of upgrades involves specifics about the occupant
protection requirements required for passengers of small school buses
(school buses with a GVWR of 10,000 lb or less). In response to NHTSA's
school bus research findings, this NPRM proposes to require small
school buses to have lap/shoulder belts instead of just lap belts. The
lap/shoulder belts would have to fit all passengers ages 6 through
adult, and be equipped with retractors. The lap/shoulder belts would
have to meet the existing anchorage strength requirements for lap/
shoulder belts in FMVSS No. 210 and would be subject to new
requirements for belt anchor location and torso belt adjustability.
FMVSS No. 207 would also be amended to apply to passenger seats in
small school buses. A newly-developed ``quasi-static'' test requirement
(discussed in the next section of this preamble) would be adopted into
FMVSS No. 222 to test school bus seats with lap/shoulder belts, to help
ensure that seat backs incorporating lap/shoulder belts are strong
enough to withstand the forward pull of the torso belts in a crash and
the forces imposed on the seat from unbelted passengers to the rear of
the belted occupants. These requirements would add to existing
compartmentalization requirements for seat performance (e.g., seat
performance forward, S5.1.3 of FMVSS No. 222, and seat performance
rearward, S5.1.4). A minimum seat belt width of 15 inches would be
specified for all school bus seats with lap/shoulder belts.
The third set of upgrades involves requirements for voluntarily-
installed seat belts on large school buses. For large school buses with
voluntarily-installed lap/shoulder belts, the vehicle would be subject
to the requirements described above for lap/shoulder belts on small
school buses, except FMVSS No. 207 would not apply to the passenger
seats. The quasi-static test procedures for small school buses would
slightly vary from those applying to seats on large school buses with
voluntary lap/shoulder belts, to account for crash characteristic
differences of large school buses versus small school buses. (Due to
the mass and other characteristics of the vehicles, in crashes small
school buses are subject to
[[Page 65515]]
higher severity forces than large school buses.)
For large school buses with voluntarily-installed lap belts, the
vehicles would be required to meet FMVSS No. 210 requirements of a
loading force of 22,240 N (5,000 pounds) per seating position. This
would be consistent with the existing lap belt loading requirement for
small school buses and light vehicles with lap belt only systems.
These proposed requirements are discussed below.\17\ In addition,
NHTSA has prepared a Technical Analysis that, among other things,
presents a detailed analysis of data, engineering studies, and other
information supporting these proposals.\18\ A copy of this Technical
Analysis will be placed in the docket.
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\17\ In Appendix A to this preamble, we list the FMVSSs affected
by this NPRM and the proposed amendments to those standards.
\18\ NHTSA Technical Analysis to Support Upgrading the Passenger
Crash Protection in School Buses (September 2007).
---------------------------------------------------------------------------
a. Improving the Compartmentalized School Bus Interior of Both Small
and Large School Buses
Seat back height. At present, school bus seat back height
is specified at S5.1.2 of FMVSS No. 222 to be at a minimum 508
millimeters (mm) (20 inches (in)). In this NPRM, we propose that the
minimum seat back height for school bus seats be raised to 610 mm (24
in).
In NHTSA's school bus research program, when dummies representing
older students were compartmentalized with current 20-inch high seat
backs, the dummies were much more likely to override the seat and make
head contact with test dummies that were placed in seats forward of the
dummies. While the injury potential of these contacts was not
quantifiable, dummies overriding seats means that the
compartmentalization was not working. The highest HIC 15 value was
registered when a 50th percentile male dummy behind a 20-inch seat back
contacted the seat back two rows ahead. In cases where incidental
contact did occur, the HIC 15 values tended to be very high. In two
cases, the HIC 15 values were over 2,000 and the third was over 5,000.
For the 24-inch seat backs, there was only dummy interaction between
the rows of seats if both the forward and rearward dummies were 50th
percentile male dummies. The high seat back seats effectively prevented
the passengers from overriding the seat backs.
In the past, NHTSA has been informed that with the higher seat
backs, drivers are not able to see and supervise the children. However,
NHTSA is not aware of data showing that the higher seat backs result in
supervision problems. NHTSA notes that four states (Illinois, New
Jersey, New York, and Ohio) plus many other school districts require
their school bus seats to have 24-inch seat backs. These states
represent about 20 percent of all students in public transportation. We
have received no reports of supervisory or safety related issues
resulting from the higher seat backs from these jurisdictions. We
request public comment on this issue.
Restraining barrier height. We propose to amend S5.2.2,
``Barrier position and rear surface area,'' to specify that the rear
surface area of the restraining barrier shall be such that in the front
projected view, the restraining barrier's surface area above the
horizontal plane that passes through the seating reference point, and
below the horizontal plane 610 mm (24 inches) above the seating
reference point, shall be not less than 90 percent of the seat bench
width in millimeters multiplied by 610 (inches multiplied by 24). We
are also proposing that restraining barriers have a minimum width of 75
percent of the seat bottom cushion at the upper portion of the
restraining barrier. This is needed to ensure that the restraining
barrier has sufficient width and area so that it sufficiently restrains
passengers. Further, we seek to clarify that the restraining barrier's
perimeter need not coincide with or lie outside of the perimeter of the
seat back of the seat for which it is required if that seat back is
higher than the minimum required by FMVSS No. 222. (Such a position
would be consistent with an April 8, 1977 NHTSA interpretation letter
to Wayne Corporation.)
Seat cushion latches. At present, FMVSS No. 222 at S5.1.5
requires seat bottom cushions to withstand an upward force that is five
times the weight of the seat bottom cushion. S5.1.5 specifies that,
with all manual attachment devices between the seat and the seat
cushion in the manufacturer's designated position for attachment, the
seat cushion shall not separate from the seat at any attachment point
when subjected to an upward force in Newtons of 5 times the mass of the
seat cushion in kilograms and multiplied by 9.8 m/s\2\, applied in any
period of not less than 1 nor more than 5 seconds, and maintained for 5
seconds.
This text of S5.1.5 has remained unchanged since 1976. NHTSA notes
that in order to allow the cushion to be removed or flipped up for
maintenance, some seat cushions have been designed to attach to the
rear seat frames with clips that swivel on and off the frame and with
stationary clips that slip under the front frame member. Such cushion
designs meet S5.1.5.
In 1984, the National Transportation Safety Board (NTSB) issued a
recommendation to NHTSA (H-84-75) that seat cushions be attached with a
fail-safe latching device to ensure that the cushions remain in their
installed position during impacts and rollovers. This recommendation
was closed based on a 1987 survey of NHTSA school bus manufacturers
which indicated that the manufacturers would voluntarily implement the
NTSB recommendation. Data indicate, however, that the school bus
manufacturers did not voluntarily implement the NTSB recommendation.
NTSB believes there was a safety need for a requirement for a
latching device because a 1987 NTSB study reported that seat cushions
came loose in 16 of 44 school bus crashes. In four of the 16 crashes,
all of the seat cushions came loose, and minor injuries were caused by
the loose seat cushions in three of the 16 crashes. The NTSB concluded
that seat cushions came free because clips were not secured to the seat
frame or were loose and free to rotate. The 1987 report indicated the
following safety concerns associated with loose cushions: Flying
cushions can strike and injure occupants; occupants can fall through
the opening left by the cushion; loose cushions may block exit routes;
and loose cushions may hide injured occupants.
In the agency's school bus research program, seat cushions became
detached in the frontal crash of a large school bus. To address the
safety concerns raised by the NTSB, NHTSA is proposing to amend S5.1.5
to require latching devices for school bus seats that have latches that
allow them to flip up or be removed for easy cleaning. We also propose
a test procedure that would require the latch to activate after a 22 kg
(48 lb) mass is placed on top of the seat at the seat cushion's center.
The 48 lb weight is that of an average 6-year-old child. The test would
ensure that any unlatched seat cushion would latch when a child
occupant sits on the seat.
b. Additional Occupant Protection Requirements for Small School Buses
(School Buses With a GVWR of 4,536 kg (10,000 lb) or Less)
The agency proposes that small school buses be required to
have lap/shoulder belts at all passenger seating positions. Since the
FMVSSs were first promulgated, small school buses passenger seats have
been required to have passenger lap belts (defined as Type 1 belts in
FMVSS No. 209) as
[[Page 65516]]
specified in FMVSS No. 208, that meet the lap belt strength
requirements specified in FMVSS No. 210. Lap belts were required
because the ratio of the mass of a potential collision partner to that
of a small school bus is larger than for a large school bus. Thus, for
vehicle-to-vehicle collisions, the deceleration of a small school bus
will be greater than for a large school bus. However, before today, we
have never sought to require lap/shoulder belts for all passenger seats
in small school buses.\19\
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\19\ FMVSS No. 208 (S4.4.5) requires buses, other than school
buses, with a GVWR of 10,000 lb or less manufactured on or after
September 1, 2007 to have lap/shoulder belts (Type 2 belts) at all
passenger seating positions other than side-facing positions.
Today's NPRM would be consistent with that requirement for the non-
school buses. (We note that the heading of S4.4.5 of FMVSS No. 208
should specify that the section does not apply to small school
buses. See https://dmses.dot.gov/docimages/pdf89/293807_web.pdf,
NHTSA letter February 19, 2004, explaining the typographical error.
Today's NPRM would correct the typographical error in S4.4.5.)
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The primary reason for proposing lap/shoulder belts is the
increased level of protection that children riding in a small school
bus gain by having a lap/shoulder belt. Lap/shoulder belts provide an
increased level of protection from lap belts by reducing the potential
of head and neck injuries in frontal impacts. The relatively poor
performance of lap belted dummies in NHTSA's frontal sled test research
is of greater concern for small school buses. Frontal crashes will tend
to be more severe for these smaller school buses than for large school
buses. Properly worn lap/shoulder belts will reduce the potential
negative effects of lap belts in severe frontal crashes while
maintaining and potentially enhancing the protection offered in other
crash modes. In NHTSA's 2002 Report to Congress, School Bus Safety:
Crashworthiness Research, NHTSA noted that the results of the
electronic data and video data showed that the dummies restrained with
lap and shoulder belts had a lower risk of head and neck injuries than
unbelted dummies.
Finally, while installation in large school buses could result in a
17 percent reduction in seating capacity, small school buses are
already configured with seating positions that can accommodate lap/
shoulder belts without a reduction in seating capacity.\20\
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\20\ The typical seating configuration of small school buses is
based on five rows of 762 mm (30 inches) two passenger seats.
Therefore, the installation of lap/shoulder belts into each seating
position should not result in a reduction in capacity.
---------------------------------------------------------------------------
Adjustability of the belt system. NHTSA proposes that
requirements be added to FMVSS No. 210 that would ensure that the seat
belt anchorages on school bus seats are designed so that the belt
system will properly fit the range of children on a school bus: The
average 6-year-old (represented by the Hybrid III 6-year-old child
dummy (45 inches tall/52 pounds)); the average 12-year-old (represented
by the Hybrid III 5th percentile female dummy (59 inches/108 pounds))
and; the large high school student (represented by the 50th percentile
adult male dummy (69 inches/172 pounds)). Proper fit for children
prevents injury and would ensure that the system performs properly in a
crash. In addition, if the lap/shoulder seat belts did not fit the
child occupant properly, there is an increased likelihood that the
child would misuse the lap/shoulder belt system by placing the shoulder
portion under the arm or behind the back. NHTSA's school bus research
results showed that when the shoulder belt was placed behind the back,
the restraint system functioned like a lap belt. Lap belts produced a
higher risk of neck injury in the testing program.
In the agency's school bus research program, we saw examples of
improper seat anchorage location. The first set of lap/shoulder belt
seats supplied for testing in the school bus research program did not
have the anchorages of the lap/shoulder belts located so that the seat
belts would fit appropriately on any of the test dummies. The torso
belt came across the dummies' heads and necks and the lap belt was high
on the abdomen instead of on the hips. After consultation with the seat
manufacturer, a second set of lap/shoulder belt equipped seats had seat
belt anchorages such that the seat belts fit all of the test dummies
(6-year-old to 50th percentile male) properly. The torso belt anchorage
was higher on the seat back to allow for proper placement of the torso
belt on taller people.\21\ Also, as in the previously supplied seats,
the shoulder belt had an adjustable anchorage that slides up and down a
second shoulder belt so it could properly adjust for the sitting height
of the typical 6-year-old through the adult size passenger.
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\21\ A torso belt anchorage located below the adult dummy's
shoulder may increase the spinal compression loading in a crash,
would increase the risk of the dummy sliding under the belt in a
crash, and would increase the risk of spinal and abdominal injuries.
The allowable location for the shoulder belt is specified in Figure
1 of the current FMVSS No. 210.
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NHTSA has tentatively determined that design requirements for the
seat belt anchorages should be specified such that the belts would be
sure to fit occupants ranging in size from the average 6-year-old child
to the average adult male. The anchorage locations were determined by
placing test dummies (6-year-old, 5th percentile female and 50th
percentile male) into the school bus seats. The results are reported in
NHTSA's Vehicle Research Test Center (VRTC) Test Report, Test
Methodology for Lap/Shoulder Belts in School Buses. NHTSA has
tentatively decided to apply the location requirements of FMVSS No.
210, S4.3.1. See Figure 1 of this preamble, below.
In addition, for the reasons discussed in the agency's technical
report supporting this NPRM, we propose that school bus seats with lap/
shoulder belts have a minimum shoulder belt adjustment range between
280 mm (11 inches) above the seating reference point and the school bus
torso belt anchor point, to ensure that the shoulder belt will fit
passengers ranging in size from a 6-year-old child to a 50th percentile
adult male.
BILLING CODE 4910-59-P
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[GRAPHIC] [TIFF OMITTED] TP21NO07.000
BILLING CODE 4910-59-C
The agency also proposes that the seat belt anchorages,
both torso and lap, be required to be integrated into the seat
structure. NHTSA proposes such integration because if we do not, we are
concerned that some manufacturers could incorporate some seat belt
anchorages into the bus floor, sidewall, or roof. Such installation
into places other than the seat structure could potentially injure
unbelted school bus passengers in a crash, or obstruct passengers
during emergency egress. However, we seek comment on whether there are
torso and lap belt anchorage designs available, other than integrated
into the seat back, that would not impede access to emergency exits or
become an injury hazard to unbelted passengers.
Improperly designed lap belts include those in which the buckle
stalk is too long and the lap belt portion of the belt assembly rides
high on the 6-year-old child's abdomen. For a proper fit, the lap belt
portion must fit low across the hips so that the crash loads are
distributed across the pelvis and not the abdominal area. Loading of
the abdomen rather than the pelvis increases the risk of internal
injuries caused by the seat belt penetration into the soft tissue of
the abdomen.
We are aware that lap belts supplied to some states have a long
buckle