[Federal Register Volume 89, Number 210 (Wednesday, October 30, 2024)]
[Rules and Regulations]
[Pages 86255-86285]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-24462]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
[Docket No. NHTSA-2024-0061]
RIN 2127-AL36
Federal Motor Vehicle Safety Standards; Anti-Ejection Glazing for
Bus Portals; Bus Emergency Exits and Window Retention and Release
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation (DOT).
ACTION: Final rule.
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SUMMARY: This final rule establishes Federal Motor Vehicle Safety
Standard (FMVSS) No. 217a, ``Anti-ejection glazing for bus portals;
Mandatory applicability beginning October 30, 2027,'' to drive the
installation of advanced glazing in over-the-road buses (motorcoaches)
and other large buses to reduce passenger and driver ejections. This
final rule, issued pursuant to the Moving Ahead for Progress in the
21st Century Act (MAP-21), specifies impactor tests of the glazing
material of side and roof windows. The impactor and impact speed
simulate the loading from an average size unrestrained adult male
impacting a window on the opposite side of a large bus in a rollover.
DATES:
Effective date: December 30, 2024.
Compliance date: The compliance date for FMVSS No. 217a and the
amendments to FMVSS No. 217 is October 30, 2027. Optional early
compliance with the standards is permitted.
Reconsideration date: If you wish to petition for reconsideration
of this rule, your petition must be received by December 16, 2024.
ADDRESSES: Petitions for reconsideration of this final rule must refer
to the docket and notice number set forth above and be submitted to the
Administrator, National Highway Traffic Safety Administration, 1200 New
Jersey Avenue SE, Washington, DC 20590. Note that all petitions
received will be posted without change to https://www.regulations.gov,
including any personal information provided.
Docket: For access to the docket to read background documents or
comments received, go to https://www.regulations.gov at any time or to
1200 New Jersey Avenue SE, West Building, Room W12-140, Washington, DC
20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. Telephone: (202) 366-9826.
Privacy Act: The petition will be placed in the docket. Anyone is
able to search the electronic form of all documents received into any
of our dockets by the name of the individual submitting the comment (or
signing the comment, if submitted on behalf of an association,
business, labor union, etc.). You may review DOT's complete Privacy Act
Statement in the Federal Register published on April 11, 2000 (Volume
65, Number 70; Pages 19477-78) or you may visit https://www.transportation.gov/individuals/privacy/privacy-act-system-records-notices.
Confidential Business Information: 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 under FOR FURTHER INFORMATION 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. When you send a submission 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).
FOR FURTHER INFORMATION CONTACT: For technical issues, you may contact
Mr. Dow Shelnutt, Office of Crashworthiness Standards, Telephone: (202)
366-8779, Facsimile: (202) 493-2739. For legal issues, you may contact
Mr. Matthew Filpi, Office of the Chief Counsel, Telephone: (202) 366-
2992, Facsimile: (202) 366-3820. The mailing address of these officials
is: The National Highway Traffic Safety Administration, 1200 New Jersey
Avenue SE, Washington, DC 20590.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Executive Summary
II. Background
a. NHTSA's Approach to Motorcoach Safety
b. U.S. DOT Motorcoach Safety Action Plan
c. Congressional Action: MAP-21 and the Motorcoach Enhanced
Safety Act
d. NHTSA's 2013 Motorcoach Seat Belt Final Rule
e. NHTSA's 2021 Motorcoach Structural Integrity Final Rule
f. Data and Safety Need for Strengthening Motorcoach Window
Glazing
g. The 2016 NPRM
[[Page 86256]]
III. NHTSA's Statutory Authority
a. National Traffic and Motor Vehicle Safety Act (Safety Act)
b. MAP-21 (Incorporating the Motorcoach Enhanced Safety Act of
2012)
IV. The Final Rule and Response to Comments
a. Establishing FMVSS No. 217a and New Requirements
b. Differences Between the NPRM and the Final Rule
V. Summary of Comments and Agency Responses
a. Overview of Comments
b. Applicability
c. Occupant Injury Protection
d. Test Procedures and Equipment
e. Performance Requirements
f. Organization of the Standard and Language Used in the
Standard
g. Compliance Date
h. Retrofitting
i. Definitions and Descriptions
j. Costs and Benefits
VI. Overview of Costs and Benefits
VII. Regulatory Notices and Analyses
I. Executive Summary
In 2007, NHTSA published a comprehensive plan on possible
improvements in motorcoach safety.\1\ NHTSA's motorcoach safety plan
identified four specific areas to most expeditiously achieve our goals:
requiring seat belts (minimizing passenger and driver ejection from the
motorcoach), improved roof strength, emergency evacuation, and fire
safety. This final rule is another step in the agency's efforts to
improve over-the-road bus (OTRB \2\) and large bus \3\ safety. This
final rule establishes a new FMVSS, FMVSS No. 217a, ``Anti-Ejection
Glazing for Bus Portals; Mandatory applicability beginning October 30,
2027,'' to mitigate partial and complete ejection of passengers from
windows on the side and roof of motorcoaches and large buses and to
ensure that emergency exits remain operable after a rollover crash.
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\1\ Docket No. NHTSA-2007-28793, NHTSA's Approach to Motorcoach
Safety.
\2\ An over-the-road bus is characterized by an elevated
passenger deck located over a baggage compartment.
\3\ Generally, certain buses with a gross vehicle weight rating
(GVWR) greater than 26,000 pounds (lb) (11,793.4 kilograms (kg)).
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This final rule fulfills a statutory mandate in the Motorcoach
Enhanced Safety Act of 2012 (Motorcoach Enhanced Safety Act), which was
incorporated and passed as part of MAP-21. The Motorcoach Enhanced
Safety Act required the DOT to prescribe regulations that address
passenger ejection in motorcoaches.\4\ Additionally, MAP-21 required
DOT to consider requiring advanced glazing standards for motorcoach
portals.
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\4\ In section 32702(6) of MAP-21, a motorcoach is defined as an
over-the-road bus, not including transit buses or school buses.
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The Motorcoach Enhanced Safety Act emphasizes anti-ejection safety
countermeasures, particularly advanced glazing. Section 32703(b)(2) of
MAP-21 directs the Secretary to consider requiring advanced glazing
standards for each motorcoach portal and to consider other portal
improvements to prevent partial and complete ejection of motorcoach
passengers, including children. Section 32703(b)(2) also states that in
prescribing such standards, the Secretary shall consider the impact of
such standards on the use of motorcoach portals as a means of emergency
egress. MAP-21 requires NHTSA to adopt a final rule if NHTSA determines
that such standards meet the requirements and considerations in
subsections (a) and (b) of section 30111 of the National Traffic and
Motor Vehicle Safety Act.\5\ As discussed in this final rule, NHTSA has
made such a determination regarding an FMVSS for motorcoaches and
certain large buses.
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\5\ MAP-21, section 32703(b) and (b)(1).
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The May 6, 2016, Notice of Proposed Rulemaking (NPRM) \6\ was among
the rulemakings issued pursuant to NHTSA's 2007 Approach to Motorcoach
Safety and DOT's Departmental Motorcoach Safety Action Plan.\7\ Both of
these agency documents recognized that there was work to be done in
protecting the public from death and serious injury in OTRB and large
bus crashes. Although there are relatively few OTRB and large bus
crashes when compared to other vehicle types, OTRB and large bus
crashes tend to be serious when they do occur because they generally
carry large numbers of passengers. Since producing these safety plans,
NHTSA has promulgated several final rules targeted at protecting OTRB
and large bus passengers. These final rules include a requirement that
all seats on OTRBs and large buses be equipped with seat belts, a
requirement that all OTRBs and large buses be equipped with electronic
stability control, and requirements for improved structural integrity
of OTRBs and large buses. This final rule is designed to work in tandem
with these other requirements to further improve OTRB and large bus
occupant safety.
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\6\ 81 FR 27904.
\7\ In 2009, DOT also issued a Motorcoach Safety Action Plan
that addressed additional factors, such as driver fatigue and
operator maintenance schedules. An update to the Departmental plan
was issued in December 2012 https://www.fmcsa.dot.gov/sites/fmcsa.dot.gov/files/docs/Motorcoach-Safety-Action-Plan-2012.pdf.
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While the agency's previous rulemakings in this area are expected
to improve OTRB and large bus safety, passenger ejection in OTRB and
large bus crashes remains a concern. Although seat belts are now
required on OTRBs and large buses, not all states require that
passengers wear seat belts on OTRBs and the agency believes seat belt
use is generally low among large bus passengers. Additionally, while
the structural integrity requirements enhance occupant safety by
providing a ``survival space'' in a rollover, they do not mitigate
glazing breakage during the crash, which would create ejection portals.
This final rule is designed to ensure window glazing remains intact
during a crash and windows do not open, even if a passenger is thrown
against the glazing during the crash.
To accomplish this safety objective, the new FMVSS No. 217a
specifies certain benchmarks that OTRB and large bus window glazing
must meet when it is contacted by an impactor projected at the window
at a specified speed. In the adopted test, a 26 kilogram (kg) (57 pound
(lb)) impactor is propelled from inside a test vehicle toward the
window glazing at 21.6 kilometers per hour (km/h) (13.4 miles per hour
(mph)). Each side window and glass panel/window on the roof would be
subject to any one of three impacts, as selected by NHTSA in a
compliance test: (a) an impact near a latching mechanism, discrete
attachment point, or (for windows without latches) the center of the
lower window edge of an intact window; (b) an impact at the center of
the daylight opening \8\ of an intact window; and (c) an impact at the
center of the daylight opening of a pre-broken glazing. The windows
would have to prevent passage of a 102-millimeter (mm) (4 inch)
diameter sphere both during and after the impact. Additionally,
emergency exits are required to remain operable after each impactor
test. The impactor and impact speed simulate the loading from an
average size unrestrained adult male thrown from one side of a large
bus and impacting a window on the opposite side of the bus in a
rollover.
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\8\ Center of daylight opening is the center of the total
unobstructed window opening that would result from the removal of
the glazing.
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These requirements would ensure that glazing is securely bonded to
window frames, no potential ejection portals are created due to
breaking of the glass, the windows remain closed when impacted, and
emergency exits remain operable after the crash. The test with the pre-
broken glazing would encourage the installation of advanced glazing.
The requirement would also help ensure the advanced glazing reasonably
retains occupants within the structural sidewall of the bus in a crash.
[[Page 86257]]
The requirements in FMVSS No. 217a apply to OTRBs and all new large
buses, with limited exceptions. The standard does not apply to school
buses, prison buses, buses with perimeter seating, or transit buses
that are not OTRBs. The FMVSS No. 217a requirements generally apply to
those buses that are also required to meet the rollover structural
integrity requirements of FMVSS No. 227, ``Bus rollover structural
integrity.'' School bus derivative buses that meet the school bus roof
crush requirements of FMVSS No. 220, ``School bus rollover
protection,'' instead of FMVSS No. 227, would also need to meet FMVSS
No. 217a.
This final rule adds a new requirement to FMVSS No. 217, ``Bus
emergency exits and window retention and release,'' that emergency exit
window latches may not protrude more than 1 inch into the window
opening when the window is open to minimize the potential for the latch
protrusions to hinder the emergency egress of passengers. This
requirement applies to all new buses that are currently subject to
FMVSS No. 217, including new school buses.
NHTSA has decided not to require existing large buses to meet the
requirements adopted today for new buses. Most of the commenters did
not support a retrofitting requirement. Upgraded window glazing on
older buses without the requisite improved structural integrity in
accordance with FMVSS No. 227 may not mitigate occupant ejections
because the advanced glazing could simply pop out of the portal due to
excessive structural deformation in a crash. The agency has also
decided not to require retrofitting of buses with improved latch
designs and window glazing materials. NHTSA believes it is not
practical to retrofit improved latch systems on windows of existing
buses because of the unique condition (including pre-existing damage or
deformation) of each existing window structure and latching mechanism.
NHTSA estimates that this rulemaking will be cost beneficial. The
agency estimates the annual cost of this rule to be $0.96 million and
annual undiscounted equivalent lives saved \9\ to be between 0.37 and
1.91. The main contributor to the cost of this rule is estimated as the
material costs for manufacturers to upgrade their window units from a
tempered/tempered double-glazed window unit to, at minimum, a
laminated/tempered double-glazed window unit. This improvement in
window unit construction would not result in a considerable weight
change. As outlined in the Final Regulatory Evaluation (FRE), NHTSA
projects that the rule would cost between $0.50 million to $4.30
million per equivalent life saved (Table 1). The net benefit/cost
impact ranges from a net benefit of $1.92 million to $18.44 million
(Table 2).
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\9\ For details concerning equivalent lives saved, reference the
FRE docketed with this final rule.
Table 1--Net Cost to Society Per Equivalent Life Saved
[In millions of 2022 dollars]
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15% belt use rate 90% belt use rate
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Undiscounted 3% 7% Undiscounted 3% 7%
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Material Costs.......................................... $0.96 $0.96 $0.96 $0.96 $0.96 $0.96
Equivalent Lives Saved \A\ \B\.......................... 1.9191 1.5064 1.1491 0.374 0.2936 0.2240
Cost per Equivalent Life Saved.......................... $0.50 $0.64 $0.84 $2.58 $3.28 $4.30
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Notes:
A--These values from the FRE account for serious injuries (MAIS 3-5) by utilizing a relative injury factor.
B--MAIS = Maximum AIS, AIS = Abbreviated Injury Scale, MAIS 0 = No Injury, MAIS 1 = Minor, MAIS 2 = Moderate, MAIS 3 = Serious, MAIS 4 = Severe, MAIS 5
= Critical, MAIS 6 = Maximum (untreatable)
Table 2--Annualized Net Benefits
[In millions of 2022 dollars]
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15% belt use rate 90% belt use rate
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Undiscounted 3% 7% Undiscounted 3% 7%
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Benefits from comprehensive costs avoided............... $24.72 $19.40 $14.80 $4.82 $3.78 $2.88
Material costs.......................................... 0.96 0.96 0.96 0.96 0.96 0.96
Net benefits............................................ 23.75 18.44 13.84 3.85 2.82 1.92
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II. Background
Since the early 2000s, NHTSA has made a concerted effort to improve
OTRB safety. These types of buses often carry children and the elderly,
which are two of the most vulnerable groups in motor vehicle crashes.
Although transportation via OTRBs is generally a safe form of travel,
the agency decided to better protect the public against unreasonable
risk of death or injury in high-occupancy vehicles through a series of
rulemakings. In many cases, crashes involving OTRBs result in
rollovers, which can significantly damage the vehicle and create
ejection portals that allow part or all of an occupant's body to be
ejected from the vehicle during a crash.
The agency has promulgated regulations that significantly reduce
the risk that passengers will be ejected from OTRBs in the event of a
rollover crash.\10\ This final rule represents yet another effort to
significantly mitigate the risk of serious injury or death resulting
from occupant ejection in OTRB crashes. It is the third rule targeted
at minimizing the risk of ejection from OTRBs during a crash that the
agency has promulgated over the past fifteen years. With this final
rule, the agency will have taken yet another large stride in improving
the safety of OTRBs, which means safer transportation for a significant
number of children, the elderly, and lower
[[Page 86258]]
income individuals. What follows in this background section is a brief
summary of NHTSA's efforts in the recent past to improve OTRB safety,
as well as a discussion about how the proposal and this final rule were
developed.
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\10\ 78 FR 70415 (Nov. 25, 2013); 80 FR 36049 (Jun 23, 2015); 86
FR 74270 (Dec 29, 2021).
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a. NHTSA's Approach to Motorcoach Safety
In 2007, NHTSA undertook a comprehensive review of motorcoach
safety issues and the course of action that the agency could pursue to
address them. The agency considered various prevention, mitigation, and
evacuation approaches in developing the plan. The agency considered
issues such as: cost and duration of testing, development, and data
analysis; likelihood that the effort would lead to the desired and
successful conclusion; target population and possible benefits that
might be realized; and anticipated cost of implementing the ensuing
requirements into the bus fleet. The results were published as
``NHTSA's Approach to Motorcoach Safety.'' This document outlined four
critical areas that the agency believed significantly contributed to
fatalities and serious injuries associated with motorcoaches: (1)
passenger ejection, (2) rollover structural integrity, (3) emergency
egress, and (4) fire safety. This was the first of two documents that
the Department produced on motorcoach safety.
b. U.S. DOT Motorcoach Safety Action Plan
In 2009, DOT issued a Departmental Motorcoach Safety Action Plan,
which outlined a department-wide strategy to enhance motorcoach safety.
In addition to the four priority action items specified in NHTSA's 2007
``NHTSA's Approach to Motorcoach Safety,'' the DOT plan identified
other strategies the Department would pursue to enhance motorcoach
safety, such as issuing rules regarding electronic stability control
systems, event data recorders, and programs addressing driver fatigue
and operator maintenance.
c. Congressional Action: MAP-21 and the Motorcoach Enhanced Safety Act
On July 6, 2012, President Obama signed MAP-21, which incorporated
the Motorcoach Enhanced Safety Act in Subtitle G. The Motorcoach
Enhanced Safety Act included a number of mandates, including
requirements that DOT issue the following regulations, among others: a
requirement that seat belts be installed in motorcoaches, a requirement
mandating improved roof strength and crush resistance standards, and
requirements that mitigate the likelihood of occupant ejection from
motorcoaches in the event of a crash.
As described in more detail below, NHTSA has issued several
regulations over the past fifteen years that have improved motorcoach
safety and satisfied Congress's statutory mandates in the Motorcoach
Enhanced Safety Act. This final rule contributes to the agency's effort
to further satisfy Congress's mandate to create anti-ejection safety
countermeasures and fits with NHTSA's other motorcoach related
rulemakings described below.
d. NHTSA's 2013 Motorcoach Seat Belt Final Rule
On November 25, 2013, NHTSA published a final rule (``seat belt
final rule'') that amended FMVSS No. 208, ``Occupant crash
protection,'' to require that all new OTRBs as well as new buses with a
gross vehicle weight rating (GVWR) greater than 11,793 kg (26,000 lb)
have lap/shoulder seat belts for each passenger seating position. This
rule fulfilled the mandated rulemaking in the Motorcoach Enhanced
Safety Act, which directed DOT to ``prescribe regulations requiring
safety belts to be installed in motorcoaches at each designated seating
position.'' In addition to satisfying the seat belt mandate in the
Motorcoach Enhanced Safety Act, this rule was also the agency's first
step toward satisfying another mandate in the Motorcoach Enhanced
Safety Act, which directed the Secretary to issue regulations that
mitigate the risk of ejection from motorcoaches. At the time, NHTSA
estimated that seat belts, when used, would be 77 percent effective in
preventing fatal injuries in motorcoach rollover crashes, primarily by
preventing ejection.
The agency remains confident that the seat belt requirement is
effective in mitigating ejection risk in crashes involving OTRBs and
other large buses. However, seat belt usage rates by motorcoach
occupants are uncertain. As an agency, NHTSA has the authority to
mandate that OTRBs and other large buses have seat belts installed at
each passenger designated seating position, but the agency does not
have the authority to mandate usage of seat belts by passengers.\11\
The agency recognized at the time that the seat belt rule would not
completely mitigate the risk of ejection, and the agency also
recognized that there would be additional risks to belted passengers in
OTRB and other large bus rollover crashes due to the lack of structural
integrity requirements for those vehicles.
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\11\ Laws requiring the use of seat belts in passenger vehicles
are set by states.
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e. NHTSA's 2021 Motorcoach Structural Integrity Final Rule
On December 29, 2021, NHTSA promulgated a final rule (``structural
integrity final rule'') that established FMVSS No. 227, ``Bus rollover
structural integrity.'' \12\ This new standard requires that buses
provide a ``survival space'' in a rollover test to protect occupants
from significant collapse of the bus structure around them.
Additionally, the new standard requires that emergency exits remain
closed during the rollover test. FMVSS No. 227 provides two significant
safety benefits: (1) it protects occupants--belted and unbelted--from
being harmed due to significant deformation of the bus structure or
large falling objects such as luggage racks; and (2) it protects belted
and unbelted occupants by minimizing the risk that emergency exits
become ejection portals that passengers could be partially or
completely ejected through.
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\12\ 86 FR 74270 (Dec. 29, 2021); Partial grant of petitions for
reconsideration, 88 FR 77523 (Nov. 13, 2023).
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The structural integrity final rule satisfies the mandate in the
Motorcoach Enhanced Safety Act that required the Secretary of
Transportation to issue a regulation improving roof strength and crush
resistance standards. Additionally, like the seat belt rule, the
structural integrity final rule also contributes to satisfying the
ejection mitigation mandate in the Motorcoach Enhanced Safety Act.
Although the promulgation of FMVSS No. 227 is expected to improve
safety outcomes in large bus rollover crashes when it goes into effect,
the agency understands that occupants will still be at risk of ejection
due to potential breakage of window glazing on large buses. Without a
requirement that window glazing and latches on buses meet certain
performance criteria, occupants could still be thrown against the
window, break the window in the process, and be ejected through the
broken window. This type of ejection is what spurred the agency to
initiate this advanced glazing rulemaking.
NHTSA's strategy has been first to seek improvements to the
rollover structural integrity of motorcoaches (roof strength and crush
resistance) and then to pursue measures that would drive use of
advanced glazing. This ordered approach is based on findings from a
NHTSA funded study \13\ that
[[Page 86259]]
found the integrity of the bus structure has a profound impact on the
effectiveness of glazing as an anti-ejection safety countermeasure.
Without a threshold standard for bus structural integrity, a twisting
motion of a bus in a rollover could simply pop out any advanced glazing
used in the windows and negate the potential benefits of the glazing in
mitigating occupant ejection.
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\13\ Motor Coach Glazing Retention Test Development for Occupant
Impact During a Rollover (Martec Study), Final Report published on
August 2006, Docket No. NHTSA-2002-11876-15.
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f. Data and Safety Need for Strengthening Motorcoach Window Glazing
Overview of Window Glazing
In the context of motor vehicles, ``glazing'' is a general term
used to describe the material used in vehicle windows. The glazing in
motor vehicles typically consists of either glass, which can be
tempered or laminated, or transparent plastics, such as acrylic or
polycarbonate.
The agency expects that manufacturers will often use laminated
glass to meet the new requirements adopted in this final rule. A single
pane of laminated glass contains two glass layers held together by an
interlayer, typically made of polyvinyl butyral (PVB). The PVB
interlayer retains a strong bond with the outer layers of glass so that
in the event the glass breaks or cracks, large shards of sharp glass do
not become free and risk cutting or seriously injuring people.
Laminated glass may crack or splinter upon impact with the ground, but
it can still provide a barrier to retain passengers within the bus if
the glazing is retained within the window frame, the PVB interlayer is
not excessively torn or punctured, and the window latch remains closed.
Tempered glass is also often used for windows on vehicles and
buses. Several OTRB manufacturers currently use tempered glass as their
glazing of choice for windows. Tempered glass is processed with
controlled thermal or chemical treatments. These treatments strengthen
the glass and create balanced internal stresses so that when the glass
does break, it breaks or crumbles into smaller granular chunks instead
of large, jagged shards. Tempered glass is stronger than laminated
glass, but an occupant impacting the window during a rollover event and
the bus impact with the ground can potentially shatter tempered glass,
causing the glazing to vacate the window frame and creating an ejection
portal.
In most passenger cars, a single layer of glazing is used for the
windows or windshield. However, multiple layers of glazing are often
used in the side windows of buses.\14\ For example, a bus may have a
double-glazed tempered/tempered side window, which means within one
window frame, there is an interior-side pane of tempered glass and an
exterior-side pane of tempered glass with an air gap in between the
two. This setup is a type of ``double-glazed'' window because there are
two layers of glazing in the window frame. Based on NHTSA's research
and industry feedback from the NPRM, the most common type of glazing
used in motorcoach side windows is a double-glazed tempered/tempered
window unit.
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\14\ OTRB manufacturers generally use this type of window for
thermal and sound insulation purposes. Having an ``air gap'' between
the window panes acts as a thermal barrier, making it easier to keep
the bus a comfortable temperature. The air gap also prevents
vibrations from passing through as easily, resulting in a quieter
ride for occupants.
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Under section 32702 of MAP-21, ``advanced glazing'' means glazing
installed in a portal on the side or the roof of a motorcoach that is
designed to be highly resistant to partial or complete occupant
ejection in all types of motor vehicle crashes. This rulemaking puts in
place a series of performance tests to prevent partial and complete
ejection of bus occupants. These tests, described below in this
preamble, include striking the unbroken and broken glazing with an
impactor and measuring both the excursion distance of the impactor
during impact and any resulting openings in the glazing after the
impact.
Data and Safety Need
There were 73 OTRB and 38 large bus fatal crashes in the 14-year
period from 2006 through 2019. Among these 111 OTRB and large bus
crashes, 52 were rollovers, 53 were frontal crashes, and 6 were side
crashes. The anti-ejection glazing requirements in this final rule are
expected to reduce ejections in all of these crash types. Of the 73
OTRBs involved in fatal crashes, 88 percent had a GVWR greater than
11,793 kg (26,000 lb).
NHTSA analyzed data from the agency's Fatality Analysis Reporting
System (FARS) from 2006 through 2019 to analyze fatal bus crashes
within the United States. During this period there were 111 fatal
crashes involving all OTRBs regardless of GVWR and other applicable
non-OTRBs with a GVWR greater than 11,793 kg (26,000 lb), resulting in
a total of 284 occupant fatalities (an average of 20.3 total occupant
fatalities per year). Tables 3 and 4 show the breakdown of the number
of crashes and fatalities by bus body type, GVWR, and crash type,
respectively. Fatalities resulting from other events such as fires or
occupants jumping from a bus were not included.
The OTRB and large bus fatalities were further categorized into two
groups representing drivers and passengers. Passenger fatalities were
significantly higher than driver fatalities, accounting for 84 percent
of the total fatalities, and were particularly prevalent in the OTRB
category. Rollover events accounted for 66 percent of all passenger
fatalities (compared to 20 percent of driver fatalities). Rollover
events are also the deadliest crash type, with 166 total fatalities in
52 crashes, resulting in 3.2 fatalities per crash.
Table 3--OTRB & Large Bus Fatal Crashes
[FARS 2006-2019]
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Rollover Front Side Total
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Over-the-road Bus............................... 40 30 3 73
Large Bus GVWR >11,793 kg....................... 12 23 3 38
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Total....................................... 52 53 6 111
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[[Page 86260]]
Table 4--OTRB & Large Bus Occupant Fatalities in Crashes
[FARS 2006-2019]
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OTRB Large Bus GVWR >11,793 Total
-------------------------- kg --------------------------------------
Crash type --------------------------
Driver Passenger Driver Passenger Driver Passenger All
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Rollover..................................................... 7 134 2 23 9 157 166
Front........................................................ 23 39 13 26 36 65 101
Side......................................................... 1 9 0 7 1 16 17
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Total.................................................... 31 182 15 56 46 238 284
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Occupant fatalities were further broken down based on ejection
(Table 5) and ejection path. Occupant ejection is highly correlated
with fatality. For all OTRB and large bus occupant fatalities, 39
percent were associated with ejection.\15\ Additionally, 71 percent of
ejected occupant fatalities occurred in rollover crashes, highlighting
the importance of ejection mitigation in rollover crashes. Rollovers
remain the largest cause of occupant fatalities, for both ejected and
non-ejected passengers, in OTRB and large bus crashes. However, anti-
ejection glazing will help prevent occupant ejection in all crash
types. During frontal impacts and side impacts, occupants are still at
risk of ejection, as shown in Table 5. Any impact where the side
windows break presents a risk of at least partial ejection for
passengers. Partial ejection from a vehicle carries the additional risk
of entrapment, as the partially ejected body part can be pinned under
the bus, which can cause serious injury and prevent the immediate
extraction of the passenger from the crash scene. Bus side windows can
shatter upon impact even from frontal crashes, as evidenced during
NHTSA's 35 mph frontal crash test of a 2000 Motor Coach Industries
motorcoach in 2009.\16\
---------------------------------------------------------------------------
\15\ Ejection data include both complete and partial ejections.
\16\ See https://www.nhtsa.gov/research-data/research-testing-databases#/vehicle/6934.
Table 5--OTRB & Large Bus Occupant Fatalities by Ejection Status
[FARS 2006-2019]
--------------------------------------------------------------------------------------------------------------------------------------------------------
OTRB Large Bus GVWR > 11,793 kg Total
Crash type -----------------------------------------------------------------------------------------------
Eject No Eject Eject No Eject Eject No Eject
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rollover................................................ 70 71 9 16 79 87
Front................................................... 21 41 6 33 27 74
Side.................................................... 5 5 1 6 6 11
-----------------------------------------------------------------------------------------------
Total............................................... 96 117 16 55 112 172
--------------------------------------------------------------------------------------------------------------------------------------------------------
The aforementioned data show that crashes involving ejections
present a high risk of death to the occupants of these buses. The
majority of fatalities occur in rollovers, and approximately 48 percent
of rollover occupant fatalities are associated with ejection.
In nearly all the OTRB and large bus fatal rollover events
discussed above, there was a significant amount of structural damage to
the roof and side structure of the vehicles, as well as open window
portals.\17\ This is a prime example of why this final rule works in
tandem with the structural integrity final rule. The structural
integrity final rule will ensure that the structure of the bus does not
cause harm to occupants or create ejection portals via emergency exits,
and this final rule will take the final step of increasing use of
advanced glazing that prevents partial or complete ejection of
motorcoach passengers and further ensures the integrity of glazing
mounting.
---------------------------------------------------------------------------
\17\ See NTSB report HAB-16/01 for September 21, 2014, OTRB
rollover crash near Red Lion Delaware; see also NTSB report HAR-18/
03 for May 14, 2016, OTRB rollover crash near Laredo Texas.
---------------------------------------------------------------------------
g. The 2016 NPRM
NPRM Proposals
On May 6, 2016, NHTSA published an NPRM that proposed the
establishment of FMVSS No. 217a, with the goal of reducing the
potential for occupant ejection in a crash. The NPRM proposed a new
dynamic impact test that would be used to drive the installation of
advanced glazing in high-occupancy buses. In this test, a 26 kg (57 lb)
impactor would be propelled from inside a test vehicle toward a window
glazing at 21.6 km/h (13.4 mph). The impactor and impact speed were
chosen because they represent what the impact force would be from an
average-sized unrestrained adult male striking the window on the
opposite side of a large bus in a rollover. Each side window, rear
window, and glazing panel/window on the roof would be subject to one of
three impacts, as selected by NHTSA in a compliance test: (a) an impact
near a latching mechanism of an intact window; (b) an impact at the
center of the daylight opening of an intact window; and (c) an impact
at the center of the daylight opening of a pre-broken window. The
window would need to prevent passage of a 102 mm (4 inch) diameter
sphere both during and after the impact to pass the test. In the
proposed tests, the agency would assess the window during the impact by
determining whether any part of the window passes a reference plane
defined during a pre-test set up procedure. Furthermore, in the
proposed test for the pre-broken glazing, the maximum displacement of
the impactor at the center of the daylight opening of subject windows
would be limited to 175 mm (6.9 inches).
[[Page 86261]]
In the NPRM, NHTSA also proposed to limit the protrusions of
emergency exit latches into the openings of windows to ensure they do
not unduly hinder emergency egress. This proposal was supported by a
recommendation from the National Transportation Safety Board (NTSB),
which had submitted a letter to NHTSA describing a crash (``Gray Summit
crash'') \18\ where occupants' clothing was caught on a window latch as
they were trying to egress the vehicle. A detailed description of the
Gray Summit crash can be found in the NPRM for this final rule. The
NPRM proposed a limit that would set the maximum protrusion of a window
latch into emergency exit openings of windows at 1 inch when the
emergency exit window is open.
---------------------------------------------------------------------------
\18\ NTSB/HAR-11/03 PB2011-916203; Multivehicle Collision
Interstate 44 Eastbound Gray Summit, Missouri, August 5, 2010;
December 2011.
---------------------------------------------------------------------------
The NPRM proposed to apply the advanced glazing requirements to:
(a) all new OTRBs (regardless of GVWR); and (b) all new buses other
than OTRBs with a GVWR greater than 11,793 kg (26,000 lb), with the
exception of school buses, prison buses, transit buses, and perimeter
seating buses. For the applicable bus types, the proposed applicable
windows included bus side and rear windows, and windows/glazing panels
on the roof of the vehicle with a minimum dimension measured through
the center of its area of 279 mm (11 inches) or greater. The NPRM
proposed a different applicability for the emergency exit window latch
protrusion requirement--the NPRM proposed that this requirement would
apply to buses covered by the new FMVSS No. 217a as well as all buses
subject to FMVSS No. 217, ``Bus emergency exits and window retention
and release.'' \19\
---------------------------------------------------------------------------
\19\ FMVSS No. 217 S3 says the standard ``applies to buses,
except buses manufactured for the purpose of transporting persons
under physical restraint.'' Accordingly, the NPRM proposed that the
latch requirement apply to all buses except buses used for
transporting persons under physical restraint.
---------------------------------------------------------------------------
Martec Study
As discussed in the NPRM, in 2003, NHTSA and Transport Canada
entered into a joint program that focused on improving glazing and
window retention on OTRBs to prevent occupant ejection.\20\ This
program is referenced in the NPRM and the sections below as the
``Martec study,'' and the data gathered from the study is the basis for
many of the proposals being adopted as part of this final rule. For the
purposes of the NPRM, the agency used this study to develop a test
procedure that realistically represented the impact loads from an
unrestrained occupant onto motorcoach glazing during a rollover event.
---------------------------------------------------------------------------
\20\ Motor Coach Glazing Retention Test Development for Occupant
Impact During a Rollover (Martec Study), Final Report published on
August 2006, Docket No. NHTSA-2002-11876-15.
---------------------------------------------------------------------------
III. NHTSA's Statutory Authority
NHTSA is issuing this final rule pursuant to and in accordance with
its authority under the National Traffic and Motor Vehicle Safety Act
and the relevant provisions of MAP-21.
a. National Traffic and Motor Vehicle Safety Act (Safety Act)
Under 49 United States Code (U.S.C.) Chapter 301, Motor Vehicle
Safety (49 U.S.C. 30101 et seq.), the Secretary of Transportation is
responsible for prescribing motor vehicle safety standards that are
practicable, meet the need for motor vehicle safety, and are stated in
objective terms (section 30111(a)). ``Motor vehicle safety'' is defined
in the Safety Act (section 30102(a)(8)) as ``the performance of a motor
vehicle or motor vehicle equipment in a way that protects the public
against unreasonable risk of accidents occurring because of the design,
construction, or performance of a motor vehicle, and against
unreasonable risk of death or injury in an accident, and includes
nonoperational safety of a motor vehicle.'' ``Motor vehicle safety
standard'' means a minimum standard for motor vehicle or motor vehicle
equipment performance (section 30102(a)(9)). When prescribing such
standards, the Secretary must consider all relevant available motor
vehicle safety information (section 30111(b)(1)). The Secretary must
also consider whether a proposed standard is reasonable, practicable,
and appropriate for the particular type of motor vehicle or motor
vehicle equipment for which it is prescribed (section 30111(b)(3)) and
the extent to which the standard will further the statutory purpose of
reducing traffic accidents and associated deaths and injuries (section
30111(b)(4)). The responsibility for promulgation of FMVSSs is
delegated to NHTSA (49 CFR 1.95).
b. MAP-21 (Incorporating the Motorcoach Enhanced Safety Act of 2012)
NHTSA is issuing this final rule in accordance with MAP-21, which
incorporates the Motorcoach Enhanced Safety Act of 2012 into Subtitle
G.\21\ Section 32703(b) of MAP-21 requires the Secretary (NHTSA by
delegation) to prescribe regulations that would address certain aspects
of motorcoach crash performance within 2 years if the agency determines
that the standards would meet the requirements and considerations of
section 30111(a) and (b) of the National Traffic and Motor Vehicle
Safety Act.\22\
---------------------------------------------------------------------------
\21\ The Motorcoach Enhanced Safety Act of 2012 is incorporated
into the Moving Ahead for Progress in the 21st Century Act, Public
Law 112-141 (Jul. 6, 2012).
\22\ Id. Sec. 32703(b).
---------------------------------------------------------------------------
Two subsections of section 32703(b) are particularly relevant to
this final rule. Subsection (b)(1) specifies that the Secretary is to
establish improved roof and roof support standards that ``substantially
improve the resistance of motorcoach roofs to deformation and intrusion
to prevent serious occupant injury in rollover crashes involving
motorcoaches.'' Subsection (b)(2) directs the Secretary to ``consider
advanced glazing standards for each motorcoach portal and [to] consider
other portal improvements to prevent partial and complete ejection of
motorcoach passengers, including children.'' \23\
---------------------------------------------------------------------------
\23\ While this final rule is mainly aimed at addressing the
rollover structural integrity of specific large bus types, the
reduced deformation of the bus structure would ensure that any
advanced glazing installed on portals would be retained on their
mounting and reduce the risk of occupant ejection in rollover
crashes. Further, the requirement that emergency exits should not
open during the rollover test would also ensure that the exits do
not become ejection portals. Thus, both subsection (b)(1) and
subsection (b)(2) are relevant to this rule.
---------------------------------------------------------------------------
MAP-21 contains other provisions pertaining to this rulemaking.
Section 32702 states that ``motorcoach'' has the meaning given to the
term ``over-the-road bus'' in section 3038(a)(3) of the Transportation
Equity Act for the 21st Century (TEA-21).\24\ Section 3038(a)(3) of
TEA-21 (see 49 U.S.C. 5310 note) defines ``over-the-road bus'' as ``a
bus characterized by an elevated passenger deck located over a baggage
compartment.'' However, section 32702 of MAP-21 excludes transit buses
and school buses from the ``motorcoach'' definition.\25\
---------------------------------------------------------------------------
\24\ Moving Ahead for Progress in the 21st Century Act, Public
Law 112-141, 32702(6).
\25\ Id. Sec. 32702(6)(A)-(B).
---------------------------------------------------------------------------
Under Sec. 32702, ``portal'' means any opening on the front, side,
rear, or roof of a motorcoach that could, in the event of a crash
involving the motorcoach, permit the partial or complete ejection of
any occupant from the motorcoach, including a young child. Section
32703(b)(2) also states that in prescribing such standards, the
Secretary shall consider the impact of such standards on the use of
motorcoach portals as a means of emergency egress.
[[Page 86262]]
MAP-21 further directs the Secretary to apply any regulation
prescribed in accordance with section 32703(b) to all motorcoaches
manufactured more than 3 years after the date on which the regulation
is published.\26\ In addition, the Secretary may assess the
feasibility, benefits, and costs of applying any requirement
established under section 32703(b)(2) to ``motorcoaches manufactured
before the date on which the requirement applies to new motorcoaches''
(retrofit).\27\ Finally, MAP-21 also authorizes the Secretary to
combine the required rulemaking actions as the Secretary deems
appropriate.\28\
---------------------------------------------------------------------------
\26\ Id. Sec. 32703(e)(1).
\27\ Id. Sec. 32703(e)(2), ``Retrofit Assessment for Existing
Motorcoaches.''
\28\ Id. Sec. 32706.
---------------------------------------------------------------------------
IV. The Final Rule and Response to Comments
a. Establishing FMVSS No. 217a and New Requirements
This final rule adopts most of the proposals from the 2016 NPRM
(the differences between the NPRM and this final rule are highlighted
in the section below). As discussed in the NPRM, this final rule
establishes a new standard within 49 CFR part 571 that will now be
referred to as FMVSS No. 217a. This new standard will set out
requirements that windows in certain types of buses must meet when
evaluated by the dynamic test procedure described in the 2016 NPRM.
Additionally, the new requirements will allow for only a 1-inch maximum
protrusion for emergency exit window latches when the emergency exit
window is open. Although there are some differences between the final
rule and the NPRM, after reviewing the public comments to the NPRM, the
agency has decided to adopt many of the proposals from the 2016 NPRM.
b. Differences Between the NPRM and the Final Rule
This final rule makes amendments to several of the proposals in the
2016 NPRM based on the comments the agency received. The most notable
change between the 2016 NPRM and this final rule is in the
applicability of FMVSS No. 217a. This final rule excludes all perimeter
seating buses, even if those buses are also OTRBs, from the
requirements in FMVSS No. 217a since these buses are also excluded from
the structural integrity requirements in FMVSS No. 227 and therefore
could lack the requisite integrity to retain advanced glazing within
the window frame. Additionally, the final rule excludes all rear
windows from FMVSS No. 217a requirements because the field data does
not indicate an ejection risk from rear windows. Other differences
between the 2016 NPRM and the final rule are minor updates to the
regulatory text which include: (1) an adjustment to the location within
FMVSS No. 217 for the new regulatory text that adds the emergency exit
latch protrusion requirement; (2) new figures to the FMVSS No. 217a
regulatory text to clarify the window pre-breakage procedure and the
emergency exit opening space; and (3) adjustments to the FMVSS No. 217a
regulatory text regarding the window pre-breakage procedure to specify
steps to take if the electric staple gun used to pierce the glazing
does not produce holes or perceivable damage to the glazing.
V. Summary of Comments and Agency Responses
a. Overview of Comments
NHTSA received 11 unique comments on the NPRM. Comments were
submitted by large bus manufacturers, including IC Bus (ICB), Van Hool
N.V. (Van Hool), Prevost and Nova Bus divisions (Prevost), and Blue
Bird Body Company (BBBC); a motorcoach operator, Greyhound Lines, Inc.
(Greyhound); industry groups, including Enhanced Protective Glass
Automotive Association (EPGAA), and School Bus Manufacturers Technical
Council (SBMTC); a U.S. government agency, the NTSB; glazing
manufacturers, including SABIC Innovative Plastics US LLP (SABIC) and
Exatec, LLC (Exatec); and a consumer advocacy group, The Advocates for
Highway and Auto Safety (Advocates).
Most commenters expressed support for an FMVSS on advanced anti-
ejection glazing and emergency exit latches that do not hinder
passenger egress, but views differed on how these concepts should be
implemented. For example, Greyhound, Prevost, and Van Hool expressed
concern that advanced glazing, specifically laminated glass, may
increase the potential for head and neck injuries of belted passengers.
Additionally, several commenters stated that the NPRM did not account
for all costs associated with the proposed rule.
Most commenting bus manufacturers and SBMTC requested that certain
bus types or window types be excluded from applicability under this
rulemaking, including entertainer buses, school buses, school bus-
derivative buses, driver's windows, windows in doors, rear windows, and
windows that are partially blocked by equipment or seating. Conversely,
NTSB requested more bus types be included in the rulemaking, such as
medium-sized buses with a GVWR of 11,793 kg (26,000 lb) or less, not
including school buses.
Exatec, ICB, and SABIC all expressed concerns that the proposed
glass pre-breakage procedure did not properly account for advanced
glazing that may not break upon application of a line load by the
electric staple gun.
No commenters supported mandating a retrofit for the glazing
requirements, but NTSB did support a retrofit requirement for the
minimum latch protrusion. A detailed discussion of comments and the
agency's responses can be found below.
b. Applicability
Bus Types
NHTSA proposed to apply the FMVSS No. 217a window glazing dynamic
impact test requirements to generally the same group of vehicles
covered by the bus rollover structural integrity NPRM published in
August 2014.\29\ NHTSA noted that both requirements should apply to
high occupancy vehicles associated with an unreasonable risk of fatal
rollover involvement. According to the data, these vehicles are
generally OTRBs regardless of GVWR, and other buses with a GVWR greater
than 11,793 kg (26,000 lb). Accordingly, the NPRM proposed that buses
subject to FMVSS No. 217a would be (a) new OTRBs (regardless of GVWR),
pursuant to the Motorcoach Enhanced Safety Act of 2012, and (b) all new
buses other than OTRBs with a GVWR greater than 11,793 kg (26,000 lb).
Similar to the bus rollover structural integrity proposal, school
buses, transit buses, and perimeter seat buses (as defined in the
August 2014 NPRM) \30\ were excluded from the FMVSS No. 217a proposed
requirements. Prison buses were also excluded from FMVSS No. 217a
proposed requirements because prison buses have bars over the windows
that would impede the impactor for the glazing dynamic impact tests.
---------------------------------------------------------------------------
\29\ 79 FR 46090 (Aug. 6, 2014).
\30\ Per the August 2014 NPRM: Transit bus means a bus that is
equipped with a stop-request system sold for public transportation
provided by, or on behalf of, a State or local government and that
is not an over-the-road bus; Perimeter-seating bus means a bus with
7 or fewer designated seating positions rearward of the driver's
seating position that are forward-facing or can convert to forward-
facing without the use of tools and is not an over-the-road bus.
---------------------------------------------------------------------------
The December 29, 2022 final rule establishing FMVSS No. 227, ``Bus
rollover structural integrity,'' excluded perimeter seating buses that
are non-OTRBs as well as those that are OTRBs
[[Page 86263]]
from the requirements in FMVSS No. 227. The November 2023 final rule
\31\ responding to petitions for reconsideration of the December 2022
final rule expanded the definition of transit buses to include buses
with a stop-request system sold for public transportation provided by,
or on behalf of, the federal government. As detailed later in this
section, this final rule adopts the 2015 NPRM proposals for
applicability of FMVSS No. 217a but extends the exclusions to include
perimeter seating buses that are OTRBs and the expanded definition of
transit buses. These buses excluded from FMVSS No. 217a requirements
are also excluded from FMVSS No. 227 and so may lack the requisite
structural integrity to ensure any advanced glazing in windows does not
pop out of its frame in a crash and thereby negate the potential
benefits of the advanced glazing.
---------------------------------------------------------------------------
\31\ 88 FR 77523.
---------------------------------------------------------------------------
Additionally, in the NPRM the agency proposed applying the
emergency exit window latch protrusion requirement to the same buses
covered by FMVSS No. 227 and all buses governed under FMVSS No. 217,
which includes all school buses. The agency is adopting the window
latch applicability proposal as part of this final rule.
Medium-Sized Buses
NTSB commented that the final rule should include medium-sized non-
school buses with GVWRs in the range of 4,536-1,793 kg (10,001-26,000
lb). It noted that these buses are typically built as body-on-chassis
vehicles without an elevated passenger deck over a baggage compartment,
so they do not fall within the ``over-the-road bus'' definition. NTSB
cited the 2009 bus crash near Dolan Springs, Arizona,\32\ and a 2014
bus crash in Davis, Oklahoma \33\ where passengers were ejected from
medium-sized buses and died as a result. The NTSB's Davis, Oklahoma
accident report stated that a lack of appropriate crashworthiness
standards contributed to the severity of passenger injuries.
---------------------------------------------------------------------------
\32\ Bus Loss of Control and Rollover, Dolan Springs, Arizona,
January 30, 2009. Highway Accident Report NTSB/HAR-10/01
(Washington, DC: NTSB 2010).
\33\ Truck-Tractor Semitrailer Median Crossover Collision with
Medium-Size Bus on Interstate 35, Davis, Oklahoma, September 26,
2014. Highway Accident Report NTSB/HAR-15/03 (Washington, DC: NTSB
2015).
---------------------------------------------------------------------------
Agency Response
As proposed in the NPRM, the agency has decided that the
requirements for FMVSS No. 217a will not be applicable to medium-sized
non-OTRBs.\34\ NHTSA bases this decision on a review of data for
medium-sized buses from 2006-2019 as shown below in Table 6. During
this period there were 37 fatalities with some degree of ejection from
crashes involving medium-sized buses. During the same period there were
112 fatal ejections in OTRBs and large buses, even though the
population of OTRBs and large buses is much smaller than the population
of medium-sized buses. Specifically, approximately 2,200 large buses
(including OTRBs) are produced annually, compared to approximately
16,000 medium-sized buses.\35\ Although there may be certain risks of
occupant ejection from medium-sized bus crashes, the agency has
concluded that medium-sized buses do not pose a sufficient safety need
to warrant application of FMVSS No. 217a to those buses.
---------------------------------------------------------------------------
\34\ Medium-sized buses have a GVWR greater than 4,536 kg
(10,000 lb) and less than or equal to 11,793 kg (26,000 lb).
\35\ Medium-Size Bus Production and Sales Supplemental
Information Report. Docket Item #30 from NTSB HWY17MH011 Highway
Investigation. https://data.ntsb.gov/Docket?ProjectID=94934.
Table 6--Fatal Crashes and Ejected Fatalities for Large Buses and Medium-Sized Buses
[FARS 2006-2019]
----------------------------------------------------------------------------------------------------------------
Avg. annual Avg. annual
Bus size Avg. annual ejection fleet sales
fatal crashes fatalities \36\
----------------------------------------------------------------------------------------------------------------
Large Bus (greater than 26,000 lb GVWR) and all OTRBs........... 7.9 8.0 2,200
Medium-Size Bus (GVWR of 10,000-26,000 lb)...................... 5.9 2.6 16,000
----------------------------------------------------------------------------------------------------------------
Data show a considerable disparity between the rate of fatal
ejections for large buses (OTRBs and other buses covered by this final
rule) versus medium-sized buses. Not only are large buses involved in
34 percent more fatal crashes on average annually, but they also have 3
times as many ejected occupant fatalities annually compared to medium-
sized buses.
---------------------------------------------------------------------------
\36\ Medium-Size Bus Roadway Departure, Return, and Rollover
Bryce Canyon City, Utah September 20, 2019. Accident Report NTSB/
HAR-21/01 PB2021-100917.
---------------------------------------------------------------------------
School buses and transit buses in the medium-sized bus range have a
very low rate of fatal ejections in rollover events. The bus rollover
structural integrity requirements for FMVSS No. 227 only apply to OTRBs
and buses other than OTRBs with a GVWR greater than 26,000 lb, meaning
that if the agency were to apply this final rule to medium-sized buses,
occupants in those buses would not receive the protections afforded by
FMVSS No. 227.\37\ One of the reasons the agency promulgated FMVSS No.
227 was because windows were popping out of place during rollover
events, creating ejection portals. Since medium-sized buses do not have
to comply with FMVSS No. 227, requiring medium-sized buses to utilize
enhanced glazing may not be effective in mitigating ejection because
the advanced glazing may pop out of the window due to excessive
structural deformation during a crash and thereby create an ejection
portal. Accordingly, it would be illogical from a safety standpoint to
make medium-sized buses subject to FMVSS No. 217a, but not to FMVSS No.
227. Thus, the agency has decided not to make medium-sized buses
applicable under this final rule.
---------------------------------------------------------------------------
\37\ FMVSS No. 227 has several express exemptions; the standard
does not apply to school buses, school bus derivative buses, transit
buses, prison buses, and perimeter-seating buses.
---------------------------------------------------------------------------
Entertainer Buses
The NPRM proposed to exclude perimeter seating buses from the final
rule with the exception of, however, if perimeter seating buses that
met the definition of an OTRB. Prevost commented that entertainer buses
should be completely exempt under the final rule, regardless of whether
they fit the definition of an OTRB. Buses referred to as entertainer
buses are generally built from an OTRB shell and can contain interior
features such as kitchens, bathrooms, bedrooms, lounge areas, dining
areas, generators, and slide out portions of the structure. The window
configuration may or may not be the same as those of other OTRBs built
as typical passenger vehicles.
[[Page 86264]]
Prevost commented that reducing the number of ejection-related
fatalities is an important aspect of motorcoach safety and must be
inherent to the design. Prevost further agreed with the intent of the
proposed regulation to mitigate the creation of ejection portals, and
to create uniformity throughout the industry products. However, Prevost
requested special consideration for an exemption from the proposed
requirements for entertainer buses. Prevost stated that an
``entertainer coach is very different from the passenger motorcoach
both in design and application. From a design perspective, they have
fewer and smaller passenger windows, offering relatively less chance of
a potential, partial, or full ejection.''
Agency Response
The agency believes that the term ``entertainer bus'' is not a term
of art to be used in the standard. The buses that Prevost described in
its comment are likely considered perimeter-seating buses, a bus type
that NHTSA defined in the NPRM \38\ and excluded from compliance in the
proposal, unless the perimeter seating bus in question fits the
definition of an OTRB. After reviewing Prevost's comment, NHTSA has
decided to maintain that under this final rule the new standard will
not be applicable to perimeter-seating buses. Further, to align the
application of FMVSS No. 217a with FMVSS No. 227, perimeter-seating
buses that also meet the definition of an OTRB will also be excluded
from FMVSS No. 217a.
---------------------------------------------------------------------------
\38\ According to the NPRM, perimeter-seating bus means a bus
with 7 or fewer designated seating positions rearward of the
driver's seating position that are forward-facing or that can
convert to forward-facing without the use of tools and is not an
over-the-road bus.
---------------------------------------------------------------------------
As stated in the FMVSS No. 227 motorcoach structural integrity
final rule, the agency does not find a reason to distinguish between
OTRBs with perimeter seating and non-OTRBs with perimeter seating.\39\
The safety data indicate no relevant differences between these vehicles
based on safety need. In other words, OTRBs with perimeter seating do
not present a greater risk of injury compared to non-OTRBs with
perimeter seating.
---------------------------------------------------------------------------
\39\ 86 FR 74284-74285.
---------------------------------------------------------------------------
Furthermore, as discussed above, the advanced glazing requirements
are most effective when paired with the improved structural integrity
required by FMVSS No. 227. Therefore, the agency is excluding OTRBs
with perimeter seating to mirror the decision made in the final rule
for FMVSS No. 227. Many of the safety benefits gained from advanced
glazing are dependent on sufficiently strong vehicle structural
elements, meaning it would not make sense to apply advanced glazing
requirements to a set of vehicles that do not have to comply with the
more stringent structural integrity requirements of FMVSS No. 227.
Lastly, to synthesize the definition with this decision in this
final rule, the agency has decided to amend the definition of a
perimeter seating bus in the regulatory text by deleting the phrase
``and is not an over the road bus'' from the end of the proposed
definition.
School Bus Derivative Buses
ICB recommended that commercial buses built from school bus designs
should not have to meet the ejection mitigation requirements of the
proposed rule. ICB noted that its commercial buses are ``much
different'' from a traditional motorcoach, meaning the data and studies
NHTSA used for the NPRM potentially would not apply to their buses. ICB
stated that the operating environment of its commercial buses derived
from school buses is more closely related to that of school buses than
the operating environment and conditions of OTRBs, meaning that the
routes ICB commercial buses are used on are generally routes involving
lower speeds and frequent stops. ICB wrote ``[t]he commercial variants
of school buses are typically used in applications such as church
buses, college campus buses, local shuttles and tours, emergency
responders, and parks and recreation departments.''
Agency Response
The agency disagrees with ICB's generalization of school bus
derivative bus designs and their operating environments. NHTSA is
therefore not excluding school bus derivative buses from FMVSS No. 217a
as part of this final rule. The agency is basing this decision on the
fact that school bus derivative buses are available for use in
intercity travel and are offered for sale with motorcoach-style
features, such as larger windows than school buses. While these buses
are not required to comply with FMVSS No. 227, ``Bus rollover
structural integrity,'' these buses are required to comply with FMVSS
No. 220, ``School bus rollover protection,'' and FMVSS No. 221,
``School bus body joint strength.'' When the agency defined the term
``school bus derivative bus'' in FMVSS No. 227, the agency defined
these buses as ``a bus that meets Federal motor vehicle safety
standards for school buses regarding emergency exits (Sec. 571.217),
rollover protection (Sec. 571.220), bus body joint strength (Sec.
571.221), and fuel system integrity (Sec. 571.301).'' To meet the
regulatory definition of a school bus derivative bus, the bus must
comply with specific school bus requirements--including the structural
integrity requirements of FMVSS Nos. 220 and 221--even if the bus is
not used for school-related purposes.
One of the agency's concerns when it promulgated the structural
integrity final rule was the possibility of window glazing popping out
of place and creating ejection portals. The school bus structural
integrity standards, FMVSS No. 220 and FMVSS No. 221, ensure the
windows in school bus derivative buses are less likely to ``pop out,''
similar to FMVSS No. 227 for OTRBs and other large buses. Thus, the
agency believes it is reasonable for school bus derivative buses to be
subject to the new FMVSS No. 217a but not to FMVSS No. 227.
ICB requested that commercial buses built from school bus designs
should not have to meet the ejection mitigation requirements of the
proposed rule. Although some of the commercial buses derived from
school bus designs are similar to school bus vehicles not subject to
the proposed rule, it is the use patterns of the buses that makes them
distinct from school buses. School buses are typically used for local
transportation of students from home to school and from school back
home. Like transit buses, school buses are typically operated at lower
rates of speed with frequent starts and stops. The commercial buses
derived from school bus designs are sold to groups that use the buses
for both intracity and intercity travel. Some of these buses utilize
larger windows and coach-style seating, making them even more like
OTRBs.
A 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.'' In other words, the definition of a ``school bus'' is
use-based--if it looks like a school bus and operates for school bus
purposes, it is a school bus and must comply with school bus
requirements. If it looks like a school bus, but is not used for school
bus purposes, it is not a school bus and does not have to comply with
all school bus requirements. This distinction in the FMVSS is a
critical reason why the agency believes school bus derivative buses
should be covered under FMVSS No. 217a. Forcing manufacturers to comply
with two separate structural integrity requirements would be illogical.
However, unlike structural integrity,
[[Page 86265]]
there is not an existing vehicle-level school bus-specific advanced
glazing standard. Therefore, NHTSA has decided not to exclude school
bus derivative buses from the dynamic impact test requirements of FMVSS
No. 217a. If a school bus derivative bus weighs greater than 11,793 kg
(26,000 lb), it will have to comply with FMVSS No. 217a.
Transit Buses
As part of this final rule, NHTSA is adopting a slightly altered
definition of the term ``transit bus.'' The definition proposed in the
NPRM read: ``a bus that is equipped with a stop-request system sold for
public transportation provided by, or on behalf of, a State or local
government and that is not an over-the-road bus.''
In considering how to define the term for this final rule, the
agency considered its response to petitions for reconsideration of the
final rule for FMVSS No. 227, ``Bus rollover structural integrity,''
concerning the definition of a transit bus. To ensure consistency among
standards, NHTSA has decided to adopt the definition adopted in the
agency's response to petitions for reconsideration of FMVSS No. 227.
This definition of ``transit bus'' differs from the definition proposed
in the NPRM.
In the petitions for reconsideration for the structural integrity
final rule, petitioners argued that buses that are manufactured as
transit buses but sold to entities that are not state or local
governments (or operated on behalf of state or local governments) are
not considered transit buses. The entities that the petitioners
described are either private operators or the federal government. The
petitioners stated that these transit-type buses are operated in a
similar manner as transit buses operated by state or local governments
and should therefore be included in the definition of ``transit bus.''
In NHTSA's responses to petitions for reconsideration of FMVSS No.
227,\40\ the agency partially granted the petitioners' request for
adjusting the transit bus definition. NHTSA amended the transit bus
definition by including transit-type buses operated by the federal
government, but not including transit-type buses operated by private
entities. NHTSA determined the federal government utilizes transit-type
buses in a similar manner as other public transit agencies, but private
operators may utilize these buses in higher-risk driving patterns. This
amended definition is also being adopted as part of this final rule
establishing FMVSS No. 217a. The amended definition of transit bus is
now:
---------------------------------------------------------------------------
\40\ 88 FR 77523.
---------------------------------------------------------------------------
``Transit bus means a bus that is equipped with a stop-request
system sold for public transportation provided by, or on behalf of, a
Federal, State, or local government and that is not an over-the-road
bus.''
Emergency Exit Latch Protrusion Limit Requirements Applicability
Two commenters requested clarification on the applicability of the
emergency exit latch protrusion limit requirement proposed in the NPRM.
ICB commented that it understands the protrusion limits are applicable
to all buses, including school buses. SBMTC stated that the protrusion
limit requirements should apply to all school buses, regardless of
GVWR. To support its request, SBMTC also noted that the NTSB-requested
latch protrusion limits are from a crash involving a school bus.
Agency Response
To clarify, in the NPRM, NHTSA proposed that the emergency exit
latch protrusion requirement be applicable to the buses to which the
dynamic impactor test would apply (OTRBs regardless of GVWR and other
large buses, except transit buses, prison buses, school buses, and
perimeter-seating buses, and school buses). NHTSA also requested
comment on the merits of requiring all buses subject to FMVSS No. 217
to meet the requirement. After reviewing the comments, the agency has
decided to adopt this proposal as part of this final rule. To avoid
confusion over the applicability of this emergency exit window latch
protrusion requirement, NHTSA is creating a new paragraph in FMVSS No.
217 as part of this final rule.
The NPRM proposed adding the protrusion limits into FMVSS No. 217
S5.4.1 and S5.4.2.2. The first section, S5.4.1, applies to emergency
exits on all buses except certain emergency exits on certain school
buses outlined in S5.2.3. The other amended section, S5.4.2.2, applies
only to school buses with a GVWR of 10,000 lb or less. The preamble of
the NPRM states ``the maximum latch plate protrusion requirement would
be applicable to the buses to which the impactor tests would apply. . .
. However, NHTSA is also proposing to extend the maximum latch plate
protrusion requirement to other buses as well . . . . NHTSA is
proposing to extend the proposed requirement to school buses also.''
\41\ The proposed amendment did not clearly indicate which bus types
would need to comply with the protrusion limits. As stated in the NPRM,
NHTSA's intent was for the protrusion limits to apply to all school
buses, regardless of GVWR. Therefore, the changes proposed in the NPRM
for FMVSS No. 217 S5.4.1 and S5.4.2.2 will not be implemented. Instead,
the requirement will be adopted in a different location in FMVSS No.
217, which is reflected in the amended regulatory text at the end of
this final rule.
---------------------------------------------------------------------------
\41\ 81 FR at 27921-27922.
---------------------------------------------------------------------------
The content of the changes is the same as what was proposed in the
NPRM, but the location has changed to be in its own section that
applies to all bus types within FMVSS No. 217. This change should
alleviate any confusion concerning the applicability of the emergency
latch protrusion requirement.
Applicable Window Types
In the NPRM, NHTSA proposed applying the dynamic impact test
requirements to all side windows, rear windows, and glazing panels/
windows on the roof of applicable buses that met the minimum size
requirements. The Motorcoach Enhanced Safety Act directs the agency to
consider requiring advanced glazing standards for ``each motorcoach
portal'' (section 32703(b)(2)). The Act defines ``portal'' as ``any
opening on the front, side, rear, or roof of a motorcoach that could,
in the event of a crash involving the motorcoach, permit the partial or
complete ejection of any occupant from the motorcoach, including a
young child'' (section 32702(9)). NHTSA applied the proposed advanced
glazing requirements to the portals the agency believed pose a valid
risk of ejection. The agency estimates that side bus windows account
for about 80 percent of portals (potential ejection routes) on buses.
The NPRM proposed not applying the dynamic impact test requirements
to the front windshield, roof hatches, or any doors that do not contain
glazing of at least the minimum size. Accident data from real-world
rollover crashes indicate that passenger ejections generally do not
occur from the front windshield, emergency doors, or service doors. As
proposed in the NPRM, the dynamic impact test procedure applies to
windows that have a minimum dimension measured through the center of
their area of 279 mm (11 in) or greater.
The NPRM proposed to amend FMVSS No. 217 to specify in S5.4.1 of
the standard that emergency exit latches and other related release
mechanisms not protrude more than 25 mm (1 inch)
[[Page 86266]]
into the opening of an emergency exit when the window is opened to the
minimum emergency egress opening (allowing passage of an ellipsoid 500
mm (19.7 inches) wide by 330 mm (11.8 inches) high). The purpose of
this proposed requirement was to limit the potential for objects such
as latch plates to protrude into the emergency exit window opening
space even when the protrusion still allows the exit window to meet the
opening size requirements. These requirements were proposed in the NPRM
to only apply to emergency exit windows.
Minimum Window Size
Regarding minimum dimensions, ICB and Advocates provided comments
and recommendations for changes to the requirements. Advocates
expressed concern with the lack of evidence supporting the exemption
from testing of windows with a maximum dimension of 11 inches or less.
ICB stated that the minimum surface dimension should be 381 mm (15 in)
based on a typical side passenger window size for school buses.
Agency Response
The testing standard, as discussed in the Martec report, provides
that the window glazing impact loading event is modelled after a
motorcoach side rollover with an occupant from one side of the bus
being thrown from their seat and impacting glazing on the opposite side
of the bus.
As stated in the NPRM: ``The window would be tested if it is large
enough to fit the impactor face plus a 25 mm (1 inch) border around the
impactor face plate edge without contact with the window frame. The
dimensions of the dynamic impactor the agency proposed to use were 177
mm by 212 mm (7 inches by 8.3 inches).'' The headform impactor used in
FMVSS No. 217 has a 6-inch diameter, and the minimum required dimension
measured through the center of the window is 8 inches for the window to
be tested. Using a proportional relationship for the wider (8.3 inch)
dimension of the impactor in FMVSS No. 217a results in a minimum
required dimension measured through the center of the window's area of
11 inches (279 mm).
As discussed in the Martec report, the loading case was chosen as a
representative loading situation so that a minimum level of protection
would be provided for all bus occupants, drivers, and passengers, for
all crash scenarios. The Martec study determined that the occupant
impacting the opposite side window would primarily be through shoulder
contact. The impactor was fabricated to represent the mass, stiffness,
and contacting area of the United States side impact dummy (US-SID)
shoulder. The minimum window dimension is based upon this impactor
size. Testing a window smaller than the impactor would cause the
vehicle structure around the window to be loaded during testing, thus
lowering the force applied to the glazing material. Using an impacting
face smaller than the proposed guided impactor face in order to
evaluate smaller windows would not be representative of the loading
analysis conducted. The agency does not agree with the request to
evaluate other crash scenarios for occupant-to-window contact.
ICB requested NHTSA increase the minimum window size to match the
size of a typical school bus window, which ICB stated is 381 mm (15
inches). As discussed later in the preamble, since school bus-sized
windows are large enough to satisfy emergency exit requirements, they
are large enough to become an ejection portal that could permit the
partial or complete ejection of a passenger if the glazing is vacated
from the opening. Therefore, NHTSA will not increase the minimum window
surface dimension as ICB has requested.
Rear Windows
ICB stated that the rear windows should be exempt from the anti-
ejection requirements of FMVSS No. 217a. ICB pointed out that in
traditional motorcoaches there is typically not a rear window, and that
most bus crash injuries and fatalities involve traditional
motorcoaches. Additionally, ICB stated that it is not aware of any
crash reports for ``a survivable rollover incident that would propel an
occupant with such force to the rear of the vehicle that it would eject
them through the rear glazing.'' ICB further stated that rear windows
are usually partially blocked by forward facing seats, which makes it
less likely for passengers to be ejected out the rear of a bus. ICB
pointed to a sentence from the Martec report which ICB interpreted to
imply that the impactor anvil test does not apply to rear-window
glazing.
BBBC stated that the rear windows should be exempt on ``large
commercial buses that are constructed substantially the same as school
buses'' because they are usually partially blocked by seats.
Additionally, BBBC stated that since NHTSA's testing was only performed
on side windows, additional research would be required before
establishing performance requirements for the rear glazing.
Agency Response
After reviewing the comments from ICB and BBBC, the agency further
analyzed typical bus designs, ejection data, and fatal crash data. The
agency has concluded that rear bus windows will be excluded from
testing as part of this final rule.
In the NPRM, NHTSA proposed applying the dynamic impact test
requirements to all side windows, rear windows, and glazing panels/
windows on the roof of applicable buses that met the minimum window
size requirements. The agency recognized that OTRBs typically have the
bus engine in the rear, and therefore usually have no windows on the
rear of the bus. However, the agency stated that nothing precludes bus
designs from having windows in the rear of the bus that could be
potential ejection portals.
The crash type most likely to result in an ejection through the
rear glazing would be a rear impact. As stated by ICB and BBBC and
confirmed by NHTSA, there were no recorded fatalities in applicable
buses from rear impact crashes in the 2006-2019 FARS data. While it is
conceivable occupants could be ejected through the rear glazing in
other crash types, it is less likely. Further, as BBBC indicated, rear
windows in large buses that are not OTRBs are often substantially
blocked by the rear seats. As a result, occupants are less likely to be
ejected through the rear glazing. In the event of a partial ejection
through a rear window, the occupant is less likely to experience
serious injury or death, because there is a low likelihood the bus will
roll onto its rear side.
The requirements and evaluation procedures of FMVSS No. 217a are
based upon analysis of unbelted passenger impacting side bus windows
during a rollover crash scenario. This loading case was chosen as a
representative loading situation so that a minimum level of protection
would be provided for all bus occupants, drivers, and passengers, for
all crash scenarios. Therefore, as a practical matter, NHTSA has
decided rear windows will be exempt from the impact test requirements
of FMVSS No. 217a.
Windows Mounted on Doors and Hatches
ICB questioned whether the dynamic impact test requirements apply
to all window glazing, including those in doors and emergency exit
hatches. In their comments, ICB argued that ``NHTSA did not intend for
the glazing anti-ejection requirements to be applicable to glazings in
any door or
[[Page 86267]]
roof hatch emergency exit and we ask that NHTSA make that clear in the
final rule.'' BBBC stated that the NPRM did not ``adequately convey
NHTSA's intention to exclude windows that are part of a side or rear
door.''
Agency Response
Both BBBC and ICB stated that windows which are part of doors
should be exempt from the anti-ejection requirements. NHTSA has
observed that in current buses there are typically windows in the
emergency exit doors and in regular doors. The agency stated in the
NPRM that NHTSA would not be applying the proposed requirements to the
front windshield, or to emergency exit doors, service doors, or roof
hatches. The agency does not intend to apply the glazing ejection
mitigation requirements to the structure securing side and rear doors
to the vehicle. However, all bus windows are potential ejection portals
if the glazing material breaks. If a window in a side door or roof
hatch and has the requisite minimum dimensions of 279 mm (11 in) or
greater measured through the center of its area, that window will be
subject to the proposed anti-ejection requirements.
The agency has concluded that this final rule is applicable to all
side and roof window glazing that meet the minimum window dimensions.
Furthermore, NHTSA wishes to clarify that the anti-ejection
requirements proposed for FMVSS No. 217a do not apply to the non-window
portion of doors, service doors, or roof hatches. Any window in a door,
service door, or roof hatch would have to meet the anti-ejection
requirements if such a window exceeds the minimum size (279 mm or 11
inches) specified in S5 of FMVSS No. 217a.
School Bus Sized Windows
SBMTC commented that school bus size windows used on commercial
buses derived from school bus designs are too small to be covered by
the proposed anti-ejection requirements. BBBC, ICB, and SBMTC claimed
that since OTRBs have larger windows than the commercial buses derived
from school buses, commercial buses with these windows should not be
subject to the same requirements as traditional OTRBs. ICB indicated
that it does ``install larger `non-typical' school bus windows in some
of its commercial buses and [it is] not asking for any exemption for
these larger bus windows.''
Agency Response
First, as mentioned in the preceding paragraphs, if a bus derived
from a school bus design is not a school bus and has a GVWR greater
than 11,793 kg (26,000 lb), it will have to comply with FMVSS No. 217a.
The fact that certain school bus derivative buses may have smaller
windows does not change this requirement. Furthermore, FMVSS No. 217
requires buses other than school buses to have emergency exit windows
large enough to ``admit unobstructed passage, keeping a major axis
horizontal at all times, of an ellipsoid generated by rotating about
its minor axis an ellipse having a major axis of 50 centimeters and a
minor axis of 33 centimeters.'' Since these school bus windows are
large enough to satisfy emergency exit requirements, they are large
enough to become an ejection portal that could permit the partial or
complete ejection of a passenger if the glazing is vacated from the
opening. FARS data from 2006-2019 include 26 fatal ejections from
school buses with a GVWR greater than 26,000 lbs. This data shows that
school bus sized windows can become ejection portals.
Lastly, although school bus derivative buses may use the same sized
windows as school buses, NHTSA believes that school bus derivative
buses are more likely than school buses to be used in a manner that has
a higher risk of crashes. Therefore, although school bus derivative
buses may have smaller windows than traditional OTRBs, these windows
are large enough for a passenger, especially a child or smaller adult,
to be fully or partially ejected through if such a window is broken out
from the surrounding bus structure. Accordingly, a bus being equipped
with ``school bus sized'' windows will not create an exemption to FMVSS
No. 217a under this final rule. If the windows are large enough to be
tested with the impactor, the fact that the windows are ``school bus
sized'' will not impact their applicability to this standard.
Driver Side Windows
Both BBBC and ICB commented that because seat belts should protect
bus drivers from ejection, driver side windows should be exempt from
this final rule. ICB indicated that the seat belt usage rates for bus
drivers is as high as or higher than the 84% rate for commercial truck
drivers listed in a Federal Motor Carrier Safety Administration (FMCSA)
study.\42\
---------------------------------------------------------------------------
\42\ Safety Belt Usage by Commercial Motor Vehicle Drivers
(SBUCMVD) 2013, U.S. Department of Transportation, Federal Motor
Carrier Safety Administration (FMCSA).
---------------------------------------------------------------------------
Agency Response
The agency has decided not to exempt driver side windows from the
requirements under this final rule. FARS data from 2006-2019 show 9
drivers were fatally ejected from school buses with a GVWR greater than
26,000 lb.\43\ The numbers of ejected drivers are relatively low, but
the risk is present in bus crashes. Also, advanced glazing in driver
side windows will protect the drivers against partial ejections. Bus
manufacturers will be able to use similar anti-ejection design features
for driver side windows as those anti-ejection features used for the
remaining bus windows. Under the final standard, if a bus driver side
window meets the minimum size requirements, it will have to meet the
requirements of FMVSS No. 217a.
---------------------------------------------------------------------------
\43\ According to the 2006-2019 FARS data, 6 of these fatal
driver ejections were through a side door opening, 1 was through a
side window, 1 was through the windshield, and 1 was an unknown
ejection path.
---------------------------------------------------------------------------
Blocked Windows
SBMTC commented that some side wheelchair lift doors are
``effectively blocked by the stowed wheelchair lift'' and that as a
result, these windows do not pose a risk for ejection. ICB commented
that NHTSA should exclude glazing in ``[d]oors, such as wheelchair lift
doors, that have equipment or other items that would prevent or
restrict passenger ejection.'' ICB also commented that doors with no
adjacent seat should be exempted from the 217a requirements.
Additionally, BBBC argued that NHTSA did not intend to apply the
dynamic test requirements to glazing in wheelchair lift doors, ``which
would have a wheelchair lift between the passenger and the window.''
BBBC also stated that in many of the buses it manufactures, the rear
seats obstruct much of the rear window. BBBC stated these obstructed
windows should be exempt from the dynamic impact test requirements.
Agency Response
SBMTC, BBBC, and ICB stated that since wheelchair lift ramps block
the window in the wheelchair access door, such windows should not have
to meet the proposed anti-ejection requirements. The agency examined
different wheelchair access doors and the wheelchair lift ramps in
their stowed positions. Some lift ramps are stowed outside the bus in a
storage compartment under the bus. Other configurations stow the ramp
inside the bus in a folded position. These interior
[[Page 86268]]
ramps may partially block the door window.
Windows that have no blockage will have to meet the anti-ejection
requirements, since no part of the vehicle would block a passenger from
contacting the window. Windows completely blocked by wheelchair lift
ramps will not have to meet the anti-ejection requirements, since
passengers would not be able to contact such windows. Windows that are
partially blocked by wheelchair lift ramps would need to meet the anti-
ejection requirements if the daylight opening of such windows is large
enough such that the minimum dimensions measured through the center of
the daylight opening area is not less than 279 mm. Note that the
definition of daylight opening states that the periphery includes
surfaces 100 mm inboard of the window and 25 mm outboard of the window,
not including gaskets, weather stripping, grab handles, or seats. Also,
since bus passengers can walk about the bus while it is in motion, the
agency does not agree with ICB's suggestion to restrict the anti-
ejection requirements to only those windows which have a seating
position near that window glazing.
Emergency Exit Windows and Latches
ICB agreed with the agency that the window latch release mechanism
should not be a hindrance in evacuations through the emergency window
exit. Both BBBC and ICB argued that the protrusion limits are intended
to only apply to emergency exit windows, and not to other types of
emergency exits such as doors or hatches. Both respondents specifically
asked for the word ``window'' to be inserted into the sentence planned
for the end of FMVSS No. 217, S5.4.1 so that their interpretation of
the protrusion requirement applicability is specifically written into
the standard.
Agency Response
The NPRM was silent on protrusion concerns for emergency exit doors
and roof hatches. The NPRM did discuss latch protrusion issues in the
context of the emergency exit windows on the school bus involved in the
Gray Summit crash. Additionally, no other respondents commented on the
lack of concern for protrusions impeding passenger emergency egress
through side door or roof exits. The confusion over which emergency
exits are subject to the protrusion limits may stem from the section of
regulatory text into which the protrusion limits were placed.
FMVSS No. 217, S5.4.1 does not specifically list the emergency
exits to which that section applies. Further, the title for FMVSS No.
217 S5.4 is ``Emergency exit opening,'' not ``Window emergency exit
opening.'' Window emergency exits are a subset of roof, side, and rear
emergency exits. Placing the emergency window exit protrusion limits
into a section covering multiple types of exits may have created
confusion for the respondents that asked for this clarification. The
protrusion limit for emergency exit window latches is also to be
applied to school bus emergency exit windows, through addition of the
similar text into S5.4.2.2 of FMVSS No. 217. However, to avoid
additional confusion by including an emergency exit window specific
provision into a section devoted to small school bus emergency exit
doors, the agency has decided to place the emergency exit latch
protrusion requirement at the end of S5.4.
As mentioned above in the discussion on the protrusion limit
applicability for all buses, the agency is relocating this requirement
into a new subsection, FMVSS No. 217 S5.4.4, so that the requirement
will be more easily understood as applicable to all buses included in
FMVSS No. 217. This location also clarifies the application of the
protrusion requirements is only for window emergency exits. The NPRM's
proposed text additions to FMVSS No. 217 S5.4.1 and S5.4.2.2 are not
being adopted and the new S5.4.4 contains the planned protrusion limit
requirements. NHTSA is including the word ``window'' in the standard
for clarification as ICB and BBBC suggested.
c. Occupant Injury Protection
In the event of a rollover crash involving a large bus or OTRB,
there is concern for more than just injury or death resulting from
ejection from the bus; there is also a risk that passengers may suffer
injuries from impacting reinforced glazing during a crash. While the
main objective of this final rule is to protect occupants by preventing
ejection through windows and glazing panels, the agency has also
considered the impact forces bus occupants would experience when
contacting the advanced glazing during a crash. Several commenters
discussed this potential issue, and a summary of those comments along
with the agency's responses can be found in the paragraphs below.
Rigidity of Advanced Glazing
Greyhound, Prevost, and Van Hool suggested that advanced glazing
would be too rigid, causing an increase in the number and severity of
passenger injuries. Greyhound commented ``that NHTSA should consider
technologies that reduce ejections while not increasing impact
injuries.'' Van Hool stated that ``[t]he passenger on the rollover-side
wearing the seat belt in a bus according to this NPRM might be
victimized because in a single rollover his head will hit a surface
that is strong enough to retain the body of a free-falling passenger of
the other, non-rollover side.'' Prevost stated, based upon information
in a 2007 Los Angeles Times article, that ``[laminated] glass could
increase head and neck injuries to passengers who wear seat belts.''
Agency Response
The agency shares the respondents' concerns for injuries caused by
collisions with advanced glazing and window panels in OTRB and large
bus crashes. However, the agency disagrees with the argument that
advanced glazing may cause injuries which would not otherwise occur
from a broken or unbroken tempered glazing panel.
The Los Angeles Times article that Prevost referenced provided no
supporting information for the conclusion that laminated glazing is
harder than tempered glazing material. The agency has force deflection
data from the bus glazing panel research conducted for this final rule,
which can be seen in Table 7 below. In tests where the guided impactor
struck the center of bus windows made of a single glazing panel, the
tempered glazing panels had higher peak force levels and lower
deflections than glazing panels made from laminated glass,
polycarbonate, and acrylic. This test data indicates that tempered
glass is harder and more rigid than the other glazing types, including
laminate glass. The higher force levels and lower deflections indicate
that a bus occupant hitting tempered glazing at high speeds could
receive higher contact injuries than if they were to hit a different
type glazing material.
[[Page 86269]]
Table 7--Data From Bus Glazing Guided Impactor Testing \44\ Single Panel Window Glazing
----------------------------------------------------------------------------------------------------------------
Actual impact Peak impactor
Glazing configuration (bonding velocity (km/ Peak force (N) face excursion Interior glass pane
method) h) (mm) broken
----------------------------------------------------------------------------------------------------------------
Laminated glass (Rubber)............. 21.5 4,780 116 Yes.
Laminated Glass (Rubber)............. 21.2 5,879 106 Yes.
Tempered Glass (Rubber).............. 21.3 8,030 49 No.
Acrylic (Rubber)..................... 21.4 6,211 66 No.
Tempered Glass (Glued)............... 20.8 8,518 41 No.
Laminated Glass (Glued).............. 20.9 7,592 57 Yes.
Polycarbonate (Glued)................ 21.2 6,822 69 No.
----------------------------------------------------------------------------------------------------------------
In the case of belted occupants, a belted occupant seated against
the bus side wall is at risk of partial ejection of their upper torso,
hands, arms, neck, and head if the window breaks. It is safer for any
passenger to be retained inside the bus by an advanced glazing surface
than to be partially outside the bus when it hits and/or slides along
the pavement or ground. According to FARS data from 2006-2019, thirty-
nine percent of all large bus and OTRB fatalities were ejected, as
detailed in Table 8 below. Because the vast majority of occupants in
large bus and OTRB crashes are not ejected, this data and study prove
that, in the event of a rollover crash, it is safer for an occupant to
remain inside the vehicle than to be ejected, even though that may mean
a potential collision with an unbroken advanced glazing panel.
---------------------------------------------------------------------------
\44\ Duffy, S., & Prasad, A., National Highway Traffic Safety
Administration, Motorcoach Side Glazing Retention Research, pg 18,
(Report No. DOT HS 811 862) (Nov. 2013).
Table 8--Occupant Fatalities by Ejection Status FARS 2006-2019
[Large buses (GVWR greater than 26,000 lb) and all OTRBs]
----------------------------------------------------------------------------------------------------------------
Bus type Not ejected Ejected Total
----------------------------------------------------------------------------------------------------------------
Van-based....................................................... 1 0 1
Large Van....................................................... 0 0 0
Intercity Bus................................................... 117 96 213
Other Bus....................................................... 46 13 59
Unknown Bus..................................................... 8 3 11
----------------------------------------------------------------------------------------------------------------
Other Means of Injury Prevention
In Greyhound's comment, it urged the agency to consider alternative
technologies to prevent passenger ejection and reduce injuries.
Greyhound suggested that the advanced glazing will not prevent
fatalities due to ejection. Greyhound suggested that there are ``other
technologies, including those in use in the automotive and trucking
industries, which may have a higher likelihood of retaining passengers
in the vehicle in rollover/tipover events.''
Agency Response
NHTSA is always willing to consider specific proposals that may
enhance passenger safety in the agency's final rules. However, in this
instance, Greyhound did not provide a name or description of the
``other technologies'' that may be more effective than advanced glazing
in mitigating the risk of passenger ejection in OTRB and large bus
crashes. Additionally, Greyhound may have overlooked several general
aspects of occupant movement during a crash. All occupants come to a
stop at some point during a crash; the main question is how occupants
stop. The answer to this question plays a significant role in
determining the extent of passenger injuries or even risk of death in
rollover crashes. The proposed requirements of this rule provide
partial ejection protection for belted occupants seated against bus
windows as well as protection against partial or complete ejections of
unbelted passengers that may fall or move into the ejection portal
created by a broken window. As stated above, the agency welcomes
comments about other technologies or vehicle safety countermeasures
that others believe would be more beneficial than the requirements
proposed in the NPRM. However, in this case, there simply is not enough
detail in Greyhound's comment to compare ``other technologies'' to the
proposals in the NPRM. The agency is confident that the new
requirements adopted in this final rule will be highly effective in
mitigating the risk of passenger ejection during rollover crashes
involving large buses and OTRBs.
d. Test Procedures and Equipment
Multiple commenters discussed the dynamic impact test procedure and
the equipment used to conduct the dynamic impact test. The agency has
decided to adopt a few of the recommendations made in the comments,
which means the adopted test procedure will be slightly different from
the test procedure proposed in the NPRM. Specifically, the agency is
amending the proposed regulatory text for the window pre-breakage
procedure as well as the edge impact test procedure for increased
clarity.
Guided Impactor Specifications
Two of the commenters asked for more details to be provided for the
guided impactor test equipment. BBBC requested that NHTSA change the
word ``mass'' to the phrase ``mass to bring total mass of impactor to
26 kg'' in the proposed Figure 1 of the regulatory text, which
illustrates the guided impactor. Additionally, BBBC and SBMTC requested
more details on the foam used on the impactor face.
Agency Response
The impactor design being adopted as part of this final rule is the
same impactor design proposed in the NPRM. The agency has decided not
to change the language for the proposed impactor
[[Page 86270]]
test as BBBC requested, as the agency does not believe that these
changes are necessary to provide the clarity BBBC requested. Instead,
NHTSA has made a few changes to the impactor design figure, shown below
as Figure 1, which will be included in the regulatory text as well as a
separate technical supporting document that can be found in the docket
for this rulemaking (Technical Support Document). The changes to the
figure are designed to provide additional clarity, and the agency
believes these changes will resolve any confusion BBBC had regarding
the mass of the impactor design.
[GRAPHIC] [TIFF OMITTED] TR30OC24.017
The changes between this figure and the figure proposed in the NPRM
include (1) changing the term ``mass'' to ``ballast mass,'' (2)
changing the term ``foam'' to ``SID arm foam,'' (3) adding the ``thrust
bearing rod'' to the figure, and (4) labeling the ``impactor face
bearing.'' This figure now illustrates and names all components of the
impactor that contribute to the overall mass of 26 kg (57 lb). The
Technical Support Document includes more details and figures that
provide example masses for each component.
As proposed in the NPRM, the agency is adopting the requirement
that the total mass of the impactor be 26 kg (57 lb), which represents
the effective mass measurements from the Martec study. The impactor is
designed to represent the torso of the SID. To clarify, when the
regulatory text says that the impactor must be a total mass of 26 kg
(57 lb), it is referring to the mass of the entire impactor assembly,
not just one component of the impactor. In Figure 1 above--which will
also be adopted as part of the regulatory text--the agency has decided
to show the entire impactor assembly, and has labeled one component of
the impactor as the ``ballast mass.'' The agency believes the
clarification of the ``total mass of the impactor'' combined with
labeling the ballast mass will alleviate any confusion BBBC had on the
mass issue.
Regarding the foam used on the impactor face, in an effort to
provide greater clarity, the agency is able to share the following
additional details. The foam used on the impact side of the impactor
plate is the 50th percentile male side impact dummy (SID) arm foam. SID
arm foam is composed of a piece of urethane foam, conforming to the
properties listed in the Technical Support Document. Additional details
of the foam can be found in the Technical Support Document, and a copy
of the engineering drawing, SID-069, is also in the docket of this
final rule.
Window Pre-Breakage Test Procedure
In the NPRM, NHTSA proposed a breaking specification and method
that involves applying a line load to the glazing, to simulate the
damage the glazing could experience in a rollover prior to impact by an
occupant. The line loads would be applied at set distances on both the
interior and exterior glass plies of the laminated glazing. The window
breaking procedure would damage but not destroy laminated glazing,
while it would obliterate tempered glazing. Since tempered glazing
would be obliterated, this proposal would have the effect of
prohibiting manufacturers from having applicable bus windows made
solely from tempered glazing.
The first step in the proposed test procedure is to mark the
glazing surface on the occupant-side interior glass in a horizontal and
vertical grid of points separated by 75 mm (3 inches), with the first
point coincident with the geometric center of the daylight opening.
Next, the grid on the opposite side of the glazing would be marked. For
most glazing, the grid on the opposite side of the glazing would be
staggered to avoid tearing the PVB interlayer. For laminates, ``the
opposite side of the glazing'' means the opposing glass ply directly
opposite of the PVB interlayer. ``Staggered'' means that the 75 mm (3
inch) offset pattern has a 75 mm x 75 mm (3 inch x 3 inch) pattern on
the occupant-side interior glass and the same pattern, offset by 37.5
mm (1.5 inch) horizontally and vertically, on the outside exterior
glass surface.
For windows that are a single-pane unit, NHTSA would use the grid
pattern on the occupant-side interior surface and the staggered grid
pattern on the outside exterior surface of the glazing.
For double-glazed windows, the agency proposed using a grid pattern
on the occupant-side interior surface of the interior pane and on the
outside of the exterior pane. For double-glazed windows that consist of
one pane of tempered glass, that pane would be broken and removed, and
the remaining glazing (that is not of tempered glass) would be pre-
broken on both sides
[[Page 86271]]
(occupant interior and outside exterior) with the grid and staggered
grid patterns, respectively. For double-glazed windows that do not
consist of any tempered glass pane, it would not be practical to apply
the 75 mm (3 inch) pre-break pattern to the insulated surface (inside
the air gap) of the individual panes. For cases in which neither pane
is tempered glass, both the occupant side of the interior pane and the
outside of the exterior pane would be marked in the grid pattern, but
the patterns would not be offset (one side would not use the staggered
pattern) due to a lack of need. That is, for those windows there would
be little likelihood of tearing the PVB interlayer even when the
patterns are not offset.
The agency proposed breaking the defined grid points using an
unloaded electric staple gun, since the device worked well for that
purpose in our developmental testing. The staple gun would apply a 12.7
mm (0.5 inch) line load (with a thickness of 1.3 mm (0.05 inches)) (the
size of a standard staple) onto the glazing with a force in the range
of 3,500 newtons (N) (787 lb) to 5,000 N (1,124 lb) when the front nose
opening of the staple gun is held parallel to the glazing surface.
These staple gun specifications are intended to break the glass with a
single punch without producing tears in the PVB interlayer. These line
loads would be applied to the glazing starting with the inside surface
of the glazing, and starting with the forwardmost, lowest hole in the
pattern. NHTSA would continue applying the line loads 75 mm (3 inches)
apart, moving rearward on the bus. When the end of a row is reached,
the agency would move to the most forward hole in the next higher row,
75 mm (3 inches) from the punched row. After completing the
applications on the inside surface, the agency would repeat the process
on the outside surface.
When applying the line load, NHTSA would place a 100 mm (4 inch) by
100 mm (4 inch) piece of plywood on the opposite side of the glazing as
a reaction surface against the punch. If a particular window were
constructed such that the inner laminated material is penetrated or
damaged, the procedure would not be halted or invalidated. The impactor
test would be conducted at the conclusion of the glazing breakage
procedure. If punching a hole causes the glazing to disintegrate, as
would occur when testing tempered glazing, the procedure would be
halted for that item of glazing and the impactor test would be
conducted on what glazing, if any, remains. If there is no glazing
remaining after the hole-punching procedure, there would be a failure
to comply since the window would not be able to restrain the impactor
or prevent passage of the 102 mm (4 inch) diameter sphere.
BBBC requested that the specific electronic staple gun used during
the agency's research testing be specified in the final rule. ICB
commented that it does not understand why the FMVSS No. 226 spring-
loaded center punch breakage method is not practical for this proposed
regulation. SABIC, Exatec, and ICB each noted that it may not be
possible to break or even force holes into all types of glazing,
specifically glazing made from polycarbonate material. ICB also
requested improved clarity through the addition of figures or diagrams
for the glazing pre-breaking procedure.
Agency Response
While the agency understands BBBC's preference for a glazing
material breakage procedure identical to that used during the agency's
testing, NHTSA does not believe it is necessary to specify a model of
electronic staple gun to be used in the regulatory text and will not
being doing so as part of this final rule. Instead, the agency has
decided to specify the length over which the line load is to be applied
as well as the force applied by the staple gun to the glazing. Although
the agency did not list any force level in the NPRM's proposed
regulatory text, NHTSA believes it will be useful to include the
average force level (4,200 N (994 lb)) and standard deviation (850 N
(191 lb)) obtained from sampling the Duo Fast Model EWC electric staple
gun force levels as the target force in this final rule. This force was
adequate to break the laminate glazing's glass layer without tearing
the inner PVB material. For these reasons, NHTSA declines to accept
BBBC's suggestion to list a specific electric staple gun model in the
final rule.
ICB questioned why NHTSA developed a new glass breakage procedure
that differs from the existing glass breakage procedure in FMVSS No.
226. As stated in NHTSA's ``Motorcoach Side Glazing Retention
Research,'' \45\ ``[i]t was quickly determined that the automatic
center punch used in FMVSS No. 226 was not practical for large bus
windows and was not tested in this study.'' Due to the effort required
to actuate the center punch and the large size of motorcoach windows,
NHTSA determined the center punch used in the FMVSS No. 226 glazing
pre-breaking procedure would not be a practical tool for the FMVSS No.
217a glazing pre-breaking procedure. Accordingly, NHTSA developed the
breakage procedure proposed in the NPRM and is adopting that procedure
as part of this final rule.
---------------------------------------------------------------------------
\45\ Duffy, S., & Prasad, A., National Highway Traffic Safety
Administration, Motorcoach Side Glazing Retention Research, pg 18,
(Report No. DOT HS 811 862) (Nov. 2013).
---------------------------------------------------------------------------
SABIC, Exatec, and ICB each shared concerns that the glazing
breakage procedure could effectively preclude usage of their
polycarbonate glazing material. These commenters stated it may be
possible that certain glazing types would receive little to no marking
when attempting to break that glazing using the required glazing
breakage procedure. Their stated concern is that if no hole can be
made, then their glazing cannot pass the test. A similar concern was
addressed in the final rule for FMVSS No. 226.
Like FMVSS No. 226, the hole break pattern for FMVSS No. 217a will
be marked onto the bus's window glazing, as shown in the regulatory
text below, then the electric staple gun would be used once at each
marked location. It is possible that certain glazing may have smaller,
or no holes produced. Similar to the agency's response to the comment
in response to the FMVSS No. 226 NPRM, NHTSA believes that even if
certain glazing may have smaller, or no holes produced by the breakage
procedure being adopted in this final rule, the window may still be
weakened and should be tested in accordance with the rest of the
procedures outlined for the impact test.
Even though the agency has decided to adopt the pre-breakage test
procedure as proposed in the NPRM as part of this final rule, NHTSA has
decided to include an additional figure to the regulatory text to aid
in the clarification of the glazing pre-breakage procedure as ICB
requested. The combined proposed revision to FMVSS No. 217a is shown in
the appendix of this final rule.
Edge Impact Test Procedure
During agency review, NHTSA determined the edge impact test
procedure could be improved with three distinct updates, which are
described briefly here. The first update is to describe the impactor
positioning for an additional glazing orientation. For the scenario
where a window on the bus roof does not have a latch or other discrete
attachment point, the agency has decided to define which edge with
which to align the impactor. In order to be consistent with side
windows that do not have a latch, the agency is using the rearmost edge
of a roof window as the reference edge because if a latch were present,
it would likely be located on the rearmost edge due to the
[[Page 86272]]
requirement in FMVSS No. 217 S5.2.3.2(b). Second, the agency determined
a tolerance to properly define the lateral distance between the
impactor face plate edge and the window frame. NHTSA is defining a
tolerance of 2 mm based on the positioning of a similar
impactor as described in FMVSS No. 226, ``Ejection mitigation.'' The
third update is necessary to further clarify the alignment of the
impactor face plate with respect to a latch. Due to varying latch
designs, the center of the latch may not necessarily correspond to the
center of the location where the latch attaches to the movable portion
of the window. Because the location where the latch attaches to the
movable portion of the window is where the latch is most likely to
fail, the agency has decided to specify that location for the edge
impact procedure by referencing the latch attachment point when
aligning the impactor. The agency is adopting these three updates to
the edge impact test procedure as part of this final rule.
e. Performance Requirements
Impact Testing Displacement Limits
In the NPRM, NHTSA proposed to specify performance requirements for
windows comprised of unbroken and broken glazing when the glazing is
subjected to impactor testing. In NHTSA's impactor test of glazing near
a latching mechanism and in the impactor test of glazing at the center
of the daylight opening, an ``ejection reference plane'' would be
determined prior to the test. The plane would be based on the passage
of a 102 mm (4 inch) diameter sphere through a potential ejection
portal of the window. The agency would require that no part of the
window (excluding glazing shards) may pass this ``ejection reference
plane'' during the dynamic impact test. If any part of the window
glazing or window frame passes the plane, there would be a failure to
comply.
For unbroken glazing, the window would be subject to either of the
following two impacts, as selected by NHTSA in a compliance test: (a)
an impact near a latching mechanism, and (b) an impact at the center of
the daylight opening. The displacement limit for these tests on the
unbroken glazing was proposed to be 102 mm (4 inch) both during and
after the test.
For pre-broken glazing, the window would be subject to an impact
test at the center of the daylight opening. The displacement limit for
this test was proposed to be 175 mm (6.89 inch) during the test and 102
mm (4 inch) after the test.
Advocates expressed concerns that the pass/fail criteria for the
rule had not been adequately supported. Advocates stated that the 6.9-
inch excursion limit and the 4-inch dynamic displacement limits are
inadequate requirements. Advocates was concerned that ``[a]ny amount of
excursion exposes the occupant in contact with the window to impacts
with objects outside of the vehicle such as the roadway, and as such
should be reduced the greatest extent possible.'' Advocates requested
that the agency ``establish requirements that push the industry to
adopt the safest reasonable practices, as opposed to the bare minimum
or current average performance.''
Regarding permitted deflections, ICB provided comments and
recommendations for changes to the requirements. ICB stated that there
should not be a deflection requirement based on the ejection reference
plane as part of the requirement.
Agency Response
The agency has decided not to adjust the proposed excursion limit
of 175 mm for the pre-broken glazing impact test. Advocates stated that
the agency used the International Code Council (ICC) guardrail spacing
requirements as justification for 102 mm excursion limits in FMVSS No.
226. Advocates are incorrect in this belief, as the final rule notice
establishing FMVSS No. 226 noted that other FMVSSs (FMVSS No. 206 and
FMVSS No. 217) as well as the ICC have a 100 mm maximum limit on a
portal/opening to minimize the risk of an occupant being ejected or of
a child passing through the portal/opening. The final rule establishing
FMVSS No. 226 reported that test data highlighted an increased
likelihood of large portals forming when excursions were over 100 mm.
The agency believes that the 102 mm excursion limit based upon the
ejection reference plane remains an appropriate requirement.
Concerning the 175 mm displacement limit for the pre-broken glazing
test, the agency asked for comments and additional data in the NPRM.
NHTSA noted in the NPRM that this limit was based on two tests of a
single production bus window design. It was also noted in the NPRM that
results from laminate glazing testing conducted for the Martec study
resulted in an average displacement of 175 mm for the impactor in the
center of daylight opening impacts (using the 75 mm (3 inch) diagonally
offset pattern).
No other respondents commented either for or against the excursion
limits. Advocates stated that ``excursion exposes the occupant in
contact with the window to impacts with objects outside of the vehicle
such as the roadway, and as such should be reduced the greatest extent
possible.'' As discussed earlier, the manner in which occupants come to
a stop during a crash will contribute to the extent and severity of
their injuries. Based on data from NHTSA's ``Motorcoach Side Glazing
Retention Research,'' \46\ where different configurations of pre-broken
laminated glass window units were impacted at the Martec conditions,
the thicker PVB layer resulted in lower excursion limits and higher
impact force values for almost all of the pre-broken glazing
configurations.
---------------------------------------------------------------------------
\46\ Duffy, S., & Prasad, A., National Highway Traffic Safety
Administration, Motorcoach Side Glazing Retention Research, pg 18,
(Report No. DOT HS 811 862) (Nov. 2013).
---------------------------------------------------------------------------
Advocates did not offer any additional data, studies, or
suggestions for what a better, lower excursion limit should be for the
pre-broken glazing test. Using the data at the agency's disposal, an
excursion limit of 175 mm is reasonable and sufficient. NHTSA chose
this excursion limit based on practicability, costs, and safety needs.
Using a 100 percent thicker PVB layer yielded a 14 percent lower
excursion limit in our testing. This method is effective for
manufacturers to reduce the excursion limit if necessary to comply or
for slight improvements. The NPRM requested comments on the
practicability, costs, and potential benefits of using a lower
excursion limit such as 146 mm, which is the average excursion found
during the testing with the thicker PVB layer (using the same 75 mm
diagonally offset breaking procedure). Advocates did not provide any
comment on this aspect of the excursion limit, nor did any other
commenter. Therefore, the agency will not adjust the proposed excursion
limit of 175 mm for the pre-broken glazing impact test.
ICB also expressed doubt regarding the appropriateness of
deflection limits as part of the bus glazing anti-ejection
requirements. ICB suggested that the glazing and window frame should be
allowed to flex. The agency understands that window glazing, and
perhaps even the window frame, will flex when hit by the guided
impactor face. However, unlimited flexing, or displacement, is
undesirable because glazing deflection past the ejection reference
plane would allow tears to develop in glazing that could lead to an
ejection portal. Additionally, the displacement limit provides a means
of ensuring the
[[Page 86273]]
window does not open during the impact test, which would result in a
portal for occupant ejection. Limiting the deflection to the ejection
reference plane ensures that a minimum level of passenger retention
will be maintained by the bus window glazing material. Therefore, the
agency is not adopting ICB's recommendation to remove the deflection
limit for the unbroken window test.
Emergency Exit Window Latch Protrusion
The NTSB investigation into the Grey Summit bus crash noted that
passenger egress through the emergency exits was hindered when
passengers snagged their clothing on the emergency exit latch hardware
protruding into the egress route.\47\ Several passengers in the lead
school bus, and a witness who assisted in the evacuation, stated in
post-crash interviews that emergency egress was hindered by the design
of the emergency exit window. Particularly, the 4-inch by 3-inch
emergency release latch plate for the emergency exit window was
elevated about 1 inch from the window base and snagged the clothing of
several passengers as they were exiting through the window opening.
---------------------------------------------------------------------------
\47\ NTSB/HAR-11/03, https://www.ntsb.gov/investigations/AccidentReports/Reports/HAR1103.pdf,
---------------------------------------------------------------------------
The additional requirements as outlined in the NPRM proposed to
limit how far emergency exit latches may protrude into the emergency
exit opening. The NPRM for this rule proposed that emergency exit latch
protrusions cannot extend more than 1 inch into the opening of the
window when the window is opened to the minimum emergency egress
opening specified under FMVSS No. 217. This opening is described in
S5.4.1 as ``large enough to admit unobstructed passage, keeping a major
axis horizontal at all times, of an ellipsoid generated by rotating
about its minor axis an ellipse having a major axis of 50 centimeters
and a minor axis of 33 centimeters.'' The NPRM proposed making all
buses governed under FMVSS No. 217 applicable under this requirement.
The NTSB agreed that emergency exit window latches need to be
functional after a crash to ensure passengers can egress through all
viable exits; consequently, the NTSB supported testing the latches
after impact tests. Advocates also supported the agency's proposals to
minimize emergency exit latch protrusions and to require these latches
to remain operable following the impact testing.
Concerning the 1-inch protrusion limit proposed in the NPRM, both
the NTSB and Advocates requested a lower limit for allowable
protrusion. NTSB noted that the emergency latch in the Gray Summit
crash protruded 1 inch into the emergency exit opening; therefore the
proposed 1-inch maximum limit would not have prevented clothes from
snagging in that crash scenario. NTSB noted that the manufacturer has
since decreased the height of its buses' emergency release latch plate
so that it does not protrude into the window opening more than 0.5
inches. Advocates stated in their comments that there exist ``flush-
mount [latch] designs that entail no protrusion at all.'' However, they
added that these latches are implemented in non-motorcoach designs.
NTSB stated that, if NHTSA allows any degree of latch protrusion, the
latch should be designed to eliminate its potential to snag clothing or
otherwise impede evacuation.
SBMTC suggested NHTSA should provide a formal definition of
``opening'' as used in the proposal that ``emergency exit latches, or
other related release mechanisms, shall not protrude more than 25 mm
into the opening of the emergency exit when the window is in the open
position.'' ICB commented that the ``protrusion requirement applies to
a latch or latch mechanism that is attached and remains with the bus
body structure and not to a latch or latch mechanism that is attached
to and moves with the exit window itself.'' ICB wrote that the
protrusion limit applies to anywhere in the window opening, even if the
opening is larger than required for the passage of the ellipsoid
specified in S.5.4.1. ICB also asked if ``a latch or latch mechanism,
that is spring loaded and protrudes more than 25 mm into the window
opening in order to release the window, but then returns to a position
that protrudes less than 25 mm, would be compliant with this
requirement.''
Agency Response
The agency has decided that it cannot justify a reduction in the
emergency exit window latch protrusion requirements based on the
comments and data provided in response to the NPRM. It is unknown at
this time what the financial burden on the industry would be to require
emergency exit latches to be replaced with flush-mount designs or
reduced protrusions. It is also unproven at this time whether flush-
mount latch designs would withstand the impact forces from the FMVSS
No. 217a impact tests without additional modifications. The commenters
did not provide information on the current status of latch designs used
in different bus types, or what changes would be needed to comply with
their suggested lower protrusion limits. Therefore, although we
acknowledge that a one-inch protrusion may hinder egress in certain
cases, NHTSA is denying the requests to reduce the emergency exit
window latch protrusion limit.
ICB is correct that the protrusion limits apply only to the latch
components that remain with the bus structure. The latch protrusion in
the Grey Summit bus crash that snagged on occupants' clothing was
mounted to the bottom of the window frame. Latches and related
components that protrude into the window opening from the fixed bus
structure are difficult for occupants to avoid when attempting to climb
through the window opening during an emergency. This difficulty results
in a high likelihood of the protrusion snagging onto occupants'
clothing. If the latch components are located on the portion of the
emergency exit window that opens, the occupant would likely be able to
reduce the risk of snagging any protrusion by opening the window
farther. Thus, the protrusion limits apply only to the latch components
that remain with the bus structure when the emergency exit window is in
the open position to allow passage of the ellipsoid specified in S5.4.1
of FMVSS No. 217.
ICB stated the protrusion limit applies to anywhere in the window
opening even when the window is opened beyond what is required by
S5.4.1 of FMVSS No. 217. This statement is incorrect. As proposed in
the NPRM, the protrusion limit only applies to the window opening when
the emergency exit is opened to the amount necessary to admit
unobstructed passage of the ellipsoid specified in S5.4.1 of FMVSS No.
217.
ICB asked if ``a latch or latch mechanism, that is spring loaded
and protrudes more than 25 mm into the window opening in order to
release the window, but then returns to a position that protrudes less
than 25 mm,'' would be compliant with this requirement. An emergency
exit opening system in which part of the latch mechanism protrudes into
the opening space while the window latch lock is being released would
be acceptable, as long as the latch components are all below the
protrusion limit once the window is opened to the amount specified in
S5.4.1. For example, a lever handle could protrude more than an inch
into the opening while it is being moved from the closed position to
the open position. However, once the lever is in the position to allow
the window to be opened, all parts of
[[Page 86274]]
the lever and its attachment bracket must protrude less than one inch
from the structure to which it is attached.
Force Required To Open Emergency Exits
NTSB stated that from its accident investigations it ``found that
some passengers have difficulty in opening motorcoach windows and
evacuating from them because of the weight of the windows and the
challenge of keeping them open.'' NTSB cited results from its crash
investigations that support this concern. NTSB also requested that
NHTSA take action in this, or a future, rulemaking to address the ease
of opening such windows and their ability to remain open independently.
NTSB stated ``[s]uch action is needed to improve evacuation from
emergency exit windows for motorcoaches and school buses.''
Agency Response
While NHTSA shares the NTSB's concern for the capability of school
bus occupants to easily open emergency exits, this aspect of emergency
egress is not within the scope of this rulemaking. Therefore, NHTSA
will not be mandating requirements concerning the force required to
open emergency exits on school buses as part of this final rule.
f. Organization of the Standard and Language Used in the Standard
Several commenters provided feedback on the organization of the
proposed standard, as well as the language used in the proposed
standard. In response to these comments, the agency has decided to make
several amendments to the proposed organization and language of the
standard, which will be adopted as part of this final rule. The
amendments to the proposed organization and language are highlighted in
several of the agency response sections below.
Merging FMVSS No. 217a Into FMVSS No. 217
ICB suggested ``that there should not be a separate and distinct
regulation for FMVSS 217a Anti-Ejection Glazing for Bus Portals.'' ICB
stated that it would be better to have all bus window and glazing
requirements included in FMVSS No. 217. However, ICB did note that it
is ``helpful to keep the latch protrusion requirements separate from
the anti-ejection requirements.''
Agency Response
The agency has chosen to keep the bus anti-ejection requirements
and procedures in a separate standard. Having FMVSS No. 217a separate
from FMVSS No. 217 serves to highlight the differences in the two
standards. Additionally, having the bus glazing anti-ejection
requirements in a separate standard avoids confusion with existing
FMVSS No. 217 requirements and procedures. This separation is useful
for school bus applicability, since the planned FMVSS No. 217a has no
applicability to school buses whereas FMVSS No. 217 does have specific
requirements for school buses.
102 mm Sphere Application Force and Passage
Section 5.2(b) in the NPRM's proposed regulatory text states that
``[e]ach piece of window glazing and each surrounding window frame
shall be retained by its surrounding structure in a manner that
prevents the formation of any opening large enough to admit the passage
of a 102 mm diameter sphere under a force, including the weight of the
sphere, of up to 22 newtons.'' This wording is different from the
language used in S5.1(b) and S5.3(b). Those two sections use the phrase
``. . . when a force of no more than 22 newtons is applied with the
sphere at any vector . . .'' The text in S5.1(b) and S5.3(b) correctly
states a 22 N force is applied to the glazing by the sphere. To be
consistent, the agency has decided that the same wording in S5.1(b) and
S5.3(b) will be used in S5.2(b). Additionally, the agency has decided
to amend S5.1(b), S5.2(b), and S5.3(b) so that ``passage'' is amended
to ``complete passage.'' This change is based upon agency feedback
recommending improved clarity in the regulatory text for compliance
purposes. It was noted that without usage of the word ``complete,''
there would be no distinction between minimal, partial, and complete
passage of the sphere through the glazing. The amended language is
reflected in the final regulatory text for FMVSS No. 217a.
Testing Requirements Organization
ICB requested separate sections in the standard for each impact
test (center impact, edge impact, and pre-broken glazing impact tests)
with the requirements for each type of test in that section.
Agency Response
After reviewing the organization of the three types of tests
(center impact, edge impact, and pre-broken glazing impact tests), the
agency concluded that the requirements for each are already in separate
sections. Within the proposed regulatory text for FMVSS No. 217a, S5.1
includes the requirements for the edge impact test, S5.2 includes
requirements for the center impact test, and S5.3 includes requirements
for the pre-broken glazing impact test. Accordingly, NHTSA does not see
any need to adjust the organization of these requirements as part of
this final rule.
g. Compliance Date
When the NPRM for this rule was published, NHTSA proposed a
compliance date of 3 years after publication of a final rule. Based on
research from NHTSA's Vehicle Research and Test Center, the agency
believes that some manufacturers would need to redesign their emergency
exit latch systems or adopt a design that would meet the proposed
requirements. Also, manufacturers would have to transition from double-
glazed tempered/tempered windows to a new setup that has at least one
layer of laminated glass or advanced glazing that can meet the proposed
requirements. The agency has determined that a 3-year lead time after
publication of a final rule is appropriate as some design, testing, and
development will be necessary to certify compliance to the new
requirements.
The rollover structural integrity final rule has a compliance date
of December 30, 2024, which is 3 years after the publication date of
December 29, 2021. Similarly, the agency proposed a compliance date of
3 years after publication of the final rule for this advanced glazing
rulemaking. Since the two rulemakings were initially being developed
concurrently, and since the anti-ejection requirements are dependent
upon the rollover structural integrity requirements, the agency
proposed in the NPRM to make the compliance date of the two rulemakings
the same. The agency also proposed that, to enable manufacturers to
certify to the new requirements as early as possible, optional early
compliance with the standard would be permitted. EPGAA commented that
the glazing industry should have no issue supporting the three-year
phase-in period since ``the manufacturing technology and capacity
already exist to produce advanced glazing solutions.'' BBBC stated that
making the compliance date the same for the two rulemakings (FMVSS No.
227 and FMVSS No. 217a) is preferred only if the date is a minimum of 3
years after the publication of both final rules. ICB also requested
alignment of the implementation time for FMVSS No. 227 and FMVSS No.
217a. Van Hool stated that it would prefer to extend the crash
requirements for the retention of glazing and the opening of emergency
exits after the crash.
[[Page 86275]]
Agency Response
Since the rollover structural integrity final rule was published
significantly earlier than this anti-ejection glazing final rule, the
agency has decided not to align the compliance date of the two
standards. The agency agrees with EPGAA that the MAP-21 mandated lead
time of 3 years is sufficient for the necessary design, testing, and
development to comply with this standard. To align the compliance dates
of FMVSS No. 227 and a final rule for advanced glazing, the agency
would either need to delay the compliance date of FMVSS No. 227 or
accelerate the compliance date of advanced glazing final rule
establishing FMVSS No. 217a. As stated in the NPRM, NHTSA believes a
lead time of 3 years is an appropriate amount of time to account for
the changes required to comply with this anti-ejection glazing
standard. The agency will not decrease the lead time of this standard
to align the compliance date with FMVSS No. 227. Additionally, the
structural integrity improvements due to compliance with FMVSS No. 227
will benefit occupants during a rollover crash even if the anti-
ejection glazing improvements have not yet been implemented. Therefore,
the agency will not delay the compliance date of FMVSS No. 227 to align
with a final rule establishing FMVSS No. 217a as BBBC and ICB have
requested.
The agency is unclear about what Van Hool was requesting in it
comment on the compliance date. If Van Hool was asking for additional
lead time, it did not state how much additional time it was requesting
before implementation of improved passenger anti-ejection benefits.
Accordingly, NHTSA has decided not to grant Van Hool's request.
For the reasons discussed above, NHTSA is adopting the 3-year
compliance date as proposed in the NPRM as part of this final rule.
h. Retrofitting
Greyhound and ICB agreed with the agency that it would make little
sense to require retrofitting of bus windows without improving the
structural integrity of the bus. Greyhound indicated that any
requirements for enhanced window standards should apply only to buses
manufactured after the implementation date of those standards. NTSB
requested NHTSA consider requiring retrofit of existing buses for
improved window latch design, stating that ``NHTSA has identified
simple countermeasure latch designs that reduce latch openings when the
window is struck near the latch.''
Agency Response
The agency has decided to not require retrofitting of buses with
improved latch designs and window glazing materials as part of this
final rule. As stated in the NPRM, the simple countermeasure for latch
designs was to add a washer screwed onto the top of the existing MCI E/
J-series striker post. The agency has no data to determine if this fix
would work for other latch systems, or if other redesigns to those
latch systems would be necessary. For example, it is not known if the
other buses have enough strength at the latch anchorage locations of
each window for the improved latch system. Every window system would
require analysis and most likely testing to verify its capability to
successfully manage the new loads. Each window structure would need to
be inspected for pre-existing damage that would cause the improved
latch system to fail when subjected to the new loads. Therefore, NHTSA
disagrees with the NTSB's argument that a simple countermeasure exists
for retrofitting all existing buses. It is not practical to retrofit
improved latch systems onto existing buses because of the unique nature
of each existing window structure and latching mechanism.
Additionally, NHTSA retains its plan to not require retrofitting of
advanced glazing into existing buses. The agency agrees with Greyhound
and ICB that it makes little sense to upgrade the window glazing
without also improving the bus structure in accordance with FMVSS No.
227. Therefore, NHTSA will not require retrofitting for any
requirements of this standard.
i. Definitions and Descriptions
Daylight Opening
BBBC commented that the proposed S4 definition of ``daylight
opening'' through its use of the terms ``horizontal'' and ``vertical''
assumes the opening is essentially purely horizontal or vertical,
respectively. While BBBC stated that openings are usually one or the
other, BBBC recommended that NHTSA consider how to apply that
definition to an opening that may be in a plane that is not purely
vertical or horizontal, such as one 45 degrees to either plane.
Replying to the questions asked in the NPRM concerning Executive
Order (E.O.) 12866 and E.O. 13563, ICB and SBMTC requested improved
clarity through the addition of figures and diagrams for various terms,
including daylight opening and periphery. ICB stated that the
definition for daylight opening given in the NPRM is ``confusing and
overly complicated.'' It also asked for clarification concerning the
items to be included in the daylight opening measurement and further
suggested that any window frame, weather stripping, or flexible gasket
material should not be included in portal size measurements.
Agency Response
NHTSA is adopting the proposed definition of daylight opening;
however the specifications for daylight opening for rear windows have
been deleted.\48\ Due to the number of comments received concerning the
definition of daylight opening, NHTSA has elected to add figures and
additional details in the Technical Support Document to aid in
understanding the definition as part of this final rule. This Technical
Support Document is included in the docket for this final rule. For the
purposes of FMVSS No. 217a, ``daylight opening'' is the opening
generated when the visible glazing, including flexible material, is
removed from the window. It is the opening bounded by the bus
structure's window frame. ``Daylight opening'' applies to all side and
roof windows of the vehicle, including emergency exit windows.
``Daylight opening'' is used to help determine where the FMVSS No. 217a
guided impactor will hit.
---------------------------------------------------------------------------
\48\ Since the impact tests no longer apply to rear windows in
this final rule, there is no need for defining daylight opening for
rear windows.
---------------------------------------------------------------------------
BBBC commented that the proposed definition for daylight opening
does not account for window openings that are not purely vertical or
horizontal. BBBC is correct that while most windows are oriented
vertically or horizontally, there are applications where the window may
be installed at an angle or consist of curved glazing. The agency
believes the proposed definition of daylight opening properly accounts
for these situations where the window is not purely horizontal or
vertical. The proposed definition specifies the orientation of the
``daylight opening'' to be based on the bus's longitudinal axis and
whether the window is on the bus's side wall or roof. If the window is
installed at an angle or uses curved glazing, the daylight opening
would still be measured based on the proposed definition depending on
whether the window is located in the bus side wall or roof. Therefore,
whether a window is purely vertical or horizontal, the daylight opening
would be determined in the same manner. The Technical Support Document
provides illustrations and examples for determining the daylight
opening for curved glazing. The Technical Support Document also
addresses the comments from ICB and SBMTC, which requested
[[Page 86276]]
additional figures and clarification surrounding the definition of
daylight opening and periphery.
Portal
ICB commented that a portal is related to the opening created in
the bus structure when the window is opened. ICB stated that the term
``portal'' is confusing and that the term be replaced with ``opening.''
Agency Response
NHTSA has decided not to replace the term ``portal'' with
``opening'' as part of this final rule. The definition of a portal
according to the proposed FMVSS No. 217a text is ``an opening that
could, in the event of a crash involving the vehicle, permit the
partial or complete ejection of an occupant from the vehicle, including
a young child.'' This definition comes directly from MAP-21. An opening
is a more general term, and a portal is a specific type of opening. A
portal can be any type of opening in a bus wall, floor, or roof that
could allow even a partial ejection of an occupant in the event of a
crash. Some examples of a portal include an open window or door, a
broken window with some glazing removed, a hole in the bus wall, or an
open roof hatch. While there are no minimum dimensions associated with
portals, it must be large enough to admit at least partial passage of
an occupant, even if they are a smaller child. NHTSA will not replace
the word ``portal'' with ``opening,'' because an opening does not have
to be large enough to admit at least partial passage of an occupant.
Miscellaneous Comments on Clarification of Terms
In addition to the clarifications discussed above, ICB requested
improved clarity through the addition of figures and diagrams for
measuring minimum surface dimension of an opening and glazing pre-
breaking procedures.
Agency Response
NHTSA believes these topics are discussed in sufficient detail in
the NPRM and in this final rule. Additional details for the glazing
breaking procedures, the latch protrusion into the emergency exit when
the window is in the open position, and how to measure minimum surface
dimension of an opening are items that will be included in the agency's
compliance test procedures for this rule.
j. Costs and Benefits
In the NPRM and Preliminary Regulatory Evaluation (PRE), NHTSA
anticipated that tempered glazing would not meet the requirements of
the dynamic impact tests, particularly the pre-broken impact test, and
the agency believed the double-glazed tempered/tempered windows would
need to be replaced, at minimum, with a single-glazed laminated window.
Thus, the cost and benefit estimates assumed the manufacturers would be
upgrading from double-glazed tempered/tempered glazing to single-glazed
laminated glazing.
The target population for total lives saved was based on fatalities
from rollover crashes in applicable buses and was reduced by the
expected lives saved due to Electronic Stability Control (ESC), seat
belt usage, and rollover structural integrity. The NPRM noted that
advanced glazing would also prevent fatalities in other crash types,
but it did not include those crash types in the estimation due to lack
of need to further justify the rule.\49\
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\49\ 81 FR 27925.
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For the governing scenario of replacing double-glazed tempered/
tempered glazing with single-glazed laminated glazing, NHTSA estimated
the costs and benefits as summarized in Table 9 below. NHTSA determined
replacing a double-glazed tempered/tempered glazing with a single-
glazed laminated glazing would result in a weight decrease and cost
increase.\50\ For additional details and the calculations associated
with these data, refer to the PRE included in the docket with the NPRM.
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\50\ The agency estimated that a fully framed and assembled
double-glazed tempered/tempered window (approximately 25 square
feet) costs $340. Likewise, the agency estimated that a fully framed
and assembled single-glazed laminated window (approximately 25
square feet) costs $353.75. The incremental cost of choosing a
single-glazed laminated window over a double-glazed tempered/
tempered window is $13.75 per window or $165.00 per bus assuming 12
windows. The weight of the double-glazed tempered/tempered window
units used in NHTSA's testing were 100 lb and 110 lb (avg of 105
lb). The single-glazed laminated window unit weighed 77 lb. This
difference results in an average weight savings of 28 lb per window
unit. Assuming an average of 12 windows per bus results in 336 lb of
weight savings per bus.
Table 9--Advanced Glazing Annual Costs and Benefits From PRE
----------------------------------------------------------------------------------------------------------------
Costs Benefits
----------------------------------------------------------------------------------------------------------------
Item Value ($M) Item Amount
----------------------------------------------------------------------------------------------------------------
Material................................ $0.191 Lives Saved \A\........... 0.33-1.54 lives per year.
Fuel Savings \B\.......... 0.04 mpg.
----------------------------------------------------------------------------------------------------------------
Notes:
\A\ Range is dependent on seat belt usage, from 15 percent usage to 84 percent usage.
\B\ Fuel savings due to weight savings estimated at 336 lb per vehicle.
According to the PRE and NPRM, the main cost associated with the
requirements in this rule would be the material costs for the new
glazing types and window units. The agency also anticipated that
modifications to the window latch systems would be needed to meet the
dynamic impact test requirements. Applying these material costs to the
population of new, large buses and motorcoaches produced annually
resulted in approximately $191,000.\51\
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\51\ The agency estimated that there are 2,200 new over-the-road
and applicable large buses manufactured annually. NHTSA estimated
that MCI manufactures about 47.7 percent of the market population
and already includes laminated glazing as part of its production
window options. Assuming 12 windows per bus, the cost to equip
laminated glass instead of tempered glass is $13.75 per window, and
the cost of latch improvements is $0.05 per window, the total annual
incremental cost for new buses covered under this proposal is
$191,169 (= 2,200 x 0.477 x $0.60 + 2,200 x 0.523 x $165.60) in 2013
dollars.
---------------------------------------------------------------------------
Switching from a double-glazed tempered/tempered window unit to a
single-glazed laminated window unit would reduce the overall weight of
the window unit. This weight reduction would result in improved fuel
economy for each bus. The weight of the double-glazed tempered/tempered
window units used in NHTSA's testing were 100 lb and 110 lb (avg of 105
lb). The single-glazed laminated window unit weighed
[[Page 86277]]
77 lb. This difference resulted in an average weight savings of 28 lb
per window unit. Assuming an average of 12 window units per bus
resulted in 336 lb of weight savings per bus. Based on the calculations
outlined in the PRE, this change resulted in an increase of 0.04 mpg
per bus. Projecting that fuel economy benefit over the life of each
affected bus produced annually resulted in approximately $2.90 million
worth of fuel economy savings at a 3% discount rate.\52\ Table 10 below
summarizes the costs and benefits of the rule as outlined in the PRE.
---------------------------------------------------------------------------
\52\ A typical large bus travels 56,000 miles per year and has
an average fuel economy of 6.1 mpg. With the 47.7 percent current
compliance rate, an estimated 1,151 buses would benefit from this
fuel economy increase.
Table 10--Summary of Annualized Costs and Benefits due to the Anti-Ejection Glazing NPRM
[Costs are in millions of 2013 dollars]
--------------------------------------------------------------------------------------------------------------------------------------------------------
15% belt use rate 84% belt use rate
-----------------------------------------------------------------------------------------------
Undiscounted 3% 7% Undiscounted 3% 7%
--------------------------------------------------------------------------------------------------------------------------------------------------------
Equivalent Lives Saved.................................. 1.60 1.37 1.03 0.34 0.29 0.22
Net Cost \A\............................................ ($5.57) ($4.30) ($3.20) ($3.98) ($3.05) ($2.25)
Cost per Equivalent Lives Saved......................... ($3.48) ($3.14) ($3.11) ($11.71) ($10.52) ($10.23)
Benefits from Comprehensive Costs Avoided............... $15.44 $13.22 $9.95 $3.30 $2.82 $2.12
Net Benefits............................................ $21.02 $17.52 $13.15 $7.28 $5.87 $4.37
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: \A\ Net costs are negative because the fuel savings are expected to outweigh the material costs.
Glazing Construction for Compliance
BBBC, Prevost, Van Hool, SBMTC, and ICB expressed concerns that
usage of laminated glazing could result in increased weight and cost
per bus, leading to increased fuel usage and possibly resulting in
reduced seating capacity in buses close to their weight limit. Prevost
questioned the agency's assumption that double-glazed tempered/tempered
windows could be replaced with a single pane of laminated glazing. Van
Hool and Prevost expressed concern for changes in thermal properties,
which would directly influence costs associated with heating and
cooling of the bus interiors. Prevost also obtained a price quotation
for installing laminated glazing in its motorcoaches. According to
Prevost, for equivalent sizes, shapes, and tinting, the estimated cost
increase when compared to its current double-glazed tempered/tempered
configuration was ``on the order of five thousand dollars ($5,000) per
vehicle.'' ICB stated it uses single-paned tempered glazing for bus
windows. According to ICB, replacing this material with single paned
laminated glazing ``could add up to 200 lb of additional weight.'' Van
Hool also stated that ``[d]ouble laminate or tempered/laminated glazing
might do the trick at no expense for seating capacity, but with no gain
either.''
EPGAA agreed with the agency's conclusion that there is a weight
reduction in direct replacement of laminated for tempered glazing in
situations where the overall thickness remains the same since the
density of the plastic interlayer is about half that of glass. EPGAA
expressed doubt that there will be a significant change in the desire
of bus OEMs to employ double-glazed insulating assemblies for buses
used in colder climate zones. EPGAA stated that the insulating units
are employed to increase the interior glass temperature and thus reduce
any propensity for condensation or fogging while increasing occupant
thermal comfort. EPGAA stated that advanced glazing does not in itself
create a significant impact in thermal performance compared to
monolithic glass since it has a similar thermal conductivity.
EPGAA commented that advanced glazing would offer a benefit through
reduced sound transmission when compared to monolithic tempered glass,
creating a quieter cabin. EPGAA also commented that advanced glazing
would result in a significant reduction in UV exposure of occupants and
interior components. EPGAA stated that with the addition of optional
low emissivity or solar control layers the advanced glazing may also be
used to significantly reduce the solar load and hence air conditioning
load. EPGAA also stated that certain added layers may function to
reduce condensation or fogging thresholds and could in some cases help
to eliminate the need for the double-glazed insulating assemblies.
EPGAA concluded that while the fuel savings based on reduction in use
of insulating glass assemblies may be overestimated, there are unstated
monetary savings associated with air conditioning load reduction as
well as reduced UV exposure of occupants.
Agency Response
Based on comments and feedback from the bus manufacturers and
SBMTC, NHTSA understands most bus manufacturers will not be replacing
double-glazed tempered/tempered windows with single-glazed laminated
windows. Instead, it is more representative of the industry to assume
the manufacturers will simply exchange at least one pane of tempered
glazing with laminated glazing but keep the double-glazed window
construction. In other words, the double-glazed tempered/tempered
windows will likely be replaced with double-glazed laminated/tempered
windows, where either the interior or exterior pane is laminated
glazing. This replacement will maintain or improve the thermal and
sound insulation properties that are experienced by occupants with the
current glazing units. The cost-benefit analysis in this final rule
uses this change as the governing scenario, instead of the scenario
presented in the PRE.
This change in governing scenario results in the removal of the
weight reduction benefit that was estimated in the PRE. EPGAA stated in
its comments that there is some weight reduction when directly
replacing tempered glazing with laminated glazing due to the lower
density of the PVB interlayer compared to glass. However, the laminated
glazing is often thicker than the tempered glazing it replaces, and the
PVB interlayer only makes up approximately 6 percent of the glazing
thickness.\53\ Therefore, any weight difference is considered
negligible for
[[Page 86278]]
the purposes of the cost and benefit calculations.
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\53\ Duffy, S., & Prasad, A., National Highway Traffic Safety
Administration, Motorcoach Side Glazing Retention Research, pp. 10-
13 (Report No. DOT HS 811 862) (Nov. 2013). Washington, DC:.
---------------------------------------------------------------------------
As Prevost commented, there are additional costs to consider if
manufacturers would be replacing their current double-glazed window
units with single-glazed laminated windows. Switching from a double-
glazed tempered/tempered window construction to a double-glazed
laminated/tempered window construction will be more expensive for bus
manufacturers than switching to a single-glazed laminated window as
previously calculated. The agency estimates that a fully framed and
assembled double-glazed tempered/tempered window (approximately 25
square feet) costs $377.73. Likewise, NHTSA estimated that a fully
framed and assembled double-glazed laminated/tempered window
(approximately 25 square feet) costs $438.84. The incremental cost of
choosing a double-glazed laminated/tempered window over a double-glazed
tempered/tempered window is $61.11 per window or $733.32 per bus
(assuming 12 windows per bus). As outlined in the costs and benefits
section of this final rule, even with the higher costs associated with
this governing scenario this final rule is still cost beneficial.
Previous Rulemakings
Van Hool expressed concern that the possible positive influences of
ESC on bus rollovers were not properly accounted for. Van Hool asked
how effective an ESC system would be during a bus rollover. Further,
Van Hool proposed that the severity of an unbelted occupant's contact
with the opposite side glazing during a rollover would be mitigated by
the effects of ESC.
Prevost stated that it ``believe[s] that the estimated usage of
seat belts is higher than what is listed in the NPRM.'' Prevost also
stated that ``[s]eat belt usage is the single most important safety
system to mitigate passenger ejection and we commend NHTSA on the
attention they continue to give to this. We believe that pre-trip
safety briefings will further increase the percentage of seat belt
usage.'' Van Hool stated that any seat belt usage data is speculative
at best and that the agency manipulated the seat belt estimates ``in
order to make the numbers work.''
Van Hool commented that the effects of the requirements from FMVSS
No. 227 have not been taken into account and that there has not been
enough consideration of the performance changes to the vehicle
structure that will be created by bus designs changing to meet FMVSS
No. 227. Van Hool stated that its bus windows do not break in a
rollover test under Regulation No. 66 of the Economic Commission for
Europe of the United Nations (ECE R.66). Van Hool stated the agency has
not adequately proven that the FMVSS No. 217a impactor test represents
rollover forces acting on the windows of future buses that fulfill the
requirements of FMVSS No. 227 and/or ECE R.66.
Agency Response
Details concerning the effectiveness of ESC for buses was discussed
in both the agency's 2012 NPRM proposing to require ESC on heavy
vehicles and a 2011 agency research note.\54\ The analysis estimated
that ESC would be 40-56 percent effective against a rollover event. In
other words, 44-60 percent of the rollover events would still occur,
even with ESC installed in the heavy buses. Since ESC alone only
partially mitigates the risk of rollover crashes, there remains a need
to protect passengers from ejection conditions in applicable vehicles.
NHTSA has accounted for the crash reducing effects of ESC when
calculating the estimated lives saved from the advanced glazing
requirements in this final rule.
---------------------------------------------------------------------------
\54\ 77 FR 3076 NPRM for new FMVSS No. 136 (May 23, 2012);
Effectiveness of Stability Control Systems for Truck Tractors, DOT
HS 811 437 (Jan. 2011).
---------------------------------------------------------------------------
The agency agrees with Prevost on the importance of seat belt usage
in all motor vehicles. The agency examined seat belt usage rates of 15%
and 84% in the NPRM. For the cost-benefit analysis in this final rule,
the upper bound was increased to 90 percent. Nationally the seat belt
usage rate in passenger vehicles has been approximately 90 percent very
year from 2016 to 2021.\55\ Therefore, the agency analysis based on the
90 percent usage rate in motorcoaches is reasonable as a conservative
upper bound since usage rates in buses are not believed to be as high
as passenger vehicles. NHTSA has accounted for a range of bus occupants
using seat belts when calculating the estimated lives saved from the
advanced glazing requirements in this final rule.
---------------------------------------------------------------------------
\55\ Seat Belt Use in 2021--Overall Results, Traffic Safety
Facts Research Note, Report number DOT HS 813 241 (Dec. 2021),
https://crashstats.nhtsa.dot.gov/Api/Public/Publication/813241, last
accessed December 18, 2023.
---------------------------------------------------------------------------
The bus structural integrity rollover test used in FMVSS No. 227
and ECE R.66 is an effective test to determine a bus's capability to
maintain a survival space during a rollover event.\56\ However, in that
test, ballast weight for each occupant is strapped to the seats for the
FMVSS No. 227 evaluation. Windows are not intended to be evaluated
under loading from moving objects in that test. While the increased
structural rigidity is expected to reduce the number of fatal
ejections, those requirements do not account for passengers being
ejected through windows that have been broken by internal impacts. The
rollover structural integrity FRE estimates a 74 percent effectiveness
of ejection mitigation in preventing fatalities. It also states that
the enhanced rollover structural integrity test procedure does not
include a condition to simulate occupant loading, and therefore
estimates a midpoint effectiveness of 37 percent for unrestrained
ejected fatalities. As outlined above, this effectiveness is accounted
for when calculating the expected number of lives saved from the
requirements in this final rule.
---------------------------------------------------------------------------
\56\ Matolcsy, M., ``The Severity of Bus Rollover Accidents,''
20th International Technical Conference for the Enhanced Safety of
Vehicles, Paper 989, Lyon, France (2007). Available at: www-nrd.nhtsa.dot.gov/pdf/esv/esv20/07-0152-O.pdf.
---------------------------------------------------------------------------
Supporting Data
Van Hool stated that ``the data driving this NPRM seems to be from
1980-2004'' and that this data was collected well before seat belts
were in use. Van Hool commented that if 2010-2015 data were used there
would not be a strong case for requiring anti-ejection glazing. Van
Hool commented that ``recently released FMCSA crash data indicates the
lowest fatality rates given the higher numbers of coaches on the road
and the highest number in miles traveled.''
Van Hool also expressed doubt for the particular occupant loading
chosen in the Martec study, and the agency's usage of that loading to
develop the proposed anti-ejection requirements for this rule. Van Hool
expressed a preference to use the structural integrity rollover test
used in FMVSS No. 227 as the bus motion to study for window glazing
loading during crashes. Van Hool stated a ``passenger could not be
projected against the window, nor could he be ejected out of the bus
through the opposite side.''
Agency Response
The 1980-2004 data to which Van Hool refers was used for the Martec
report, which was completed in 2006. The data presented in the report
was the most recently available information at the time that study was
conducted. Those crashes were investigated to identify the rollover
events most likely to produce worst-case occupant to glazing impact
loads. While the Martec report and its source data are over 10
[[Page 86279]]
years old, data indicate that passengers continue to be ejected from
motorcoaches during rollover and other crashes. NHTSA did not rely on
the Martec report data as the ``driving data'' for this rule. The
driving data used for the NPRM and PRE was from 2004-2013. NHTSA has
updated that data to be from 2006 to 2019 for the final rule.
The Martec report stated that its objective was ``to improve the
level of safety protection of passengers in motorcoach crashes by
reducing the likelihood of ejection during vehicle collision or
rollover, as such ejections are associated with a high probability of
fatality.'' The report authors examined Transport Canada bus crash
investigation reports and then chose to model the passenger motion in a
bus during a crash where
. . . the bus rolled onto its side after yawing while trying to
negotiate a sharp turn at elevated speed. The bus had a significant
lateral velocity, the underside of the bus contacted the ground,
furrowed into the sod, and the bus rolled over on its side. A rear
hinged/latched emergency window (on the impacted side) was either
dislodged during the crash or had been opened prior to the rollover,
and there were fatalities due to ejections through the window
opening.\57\
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\57\ Motor Coach Glazing Retention Test Development for Occupant
Impact During a Rollover (Martec Study), Final Report published on
August 2006, Docket No. NHTSA-2002-11876-15.
The claim that a passenger could not move unobstructed to the
opposite side of a bus during a vehicle rollover does not apply to all
bus seating configurations. The Martec study appropriately used a
severe bus crash event and conducted computer simulations to determine
a possible window loading scenario caused by a passenger's unrestrained
movement during such a crash event. With this bus glazing anti-ejection
rule the agency is establishing requirements such that the retained
windows will mitigate partial ejections of belted occupants seated next
to the windows as well as retain the estimated 10 to 85 percent of
unbelted occupants. The anti-ejection requirements will mitigate the
occurrence of window portals being created by movement of unrestrained
passengers. Accordingly, the agency will not be adopting Van Hool's
recommendation to use the motion from a belted passenger in a rollover
test as the load basis for window glazing anti-ejection requirements as
part of this final rule.
VI. Overview of Costs and Benefits
After accounting for the above comments from the NPRM, NHTSA
analyzed the anticipated effects of a final rule and determined the net
result is cost beneficial. The agency anticipates that tempered glazing
will not meet the requirements of the dynamic impact tests,
particularly the pre-broken impact test. Therefore, the governing
scenario we use for the cost-benefit analysis assumes the manufacturers
will replace at least one pane of their double-glazed tempered/tempered
window units with laminated glass.
For fatality data analysis, NHTSA used FARS data from 2006-2019.
The agency decided not to use 2020 data for data summaries and averages
due to the effect of the COVID-19 pandemic on the industry. NHTSA
believes the 2020 data could disproportionately skew the costs and
benefits analysis. For injury data analysis, NHTSA used the National
Automotive Sampling System--General Estimates System (NASS-GES) data
from 2006-2015 and Crash Report Sampling System (CRSS) data from 2016-
2019. The NASS-GES system was retired in 2016 and replaced by the CRSS
system. The same 14-year period 2006-2019 was used to match the time
frame of fatality data.
The costs resulting from today's final rule are the material costs
attributed to upgrading the window glazing material and improving the
latching mechanisms as necessary. As discussed in the FRE for today's
final rule, approximately 47.7 percent of motorcoach manufacturers
currently use laminated glass in their window units. The remaining 52.3
percent of motorcoach and large bus manufacturers are assumed to use
double-glazed tempered/tempered window units, or some other glazing
construction that may not comply with the performance requirements in
this final rule. These windows will need to be upgraded to at least a
double-glazed laminated/tempered glazing window unit construction.
Additionally, NHTSA estimates that modifications to the window latch
systems for all motorcoach and large bus manufacturers will be needed
in order to meet the dynamic impact test requirements. Table 11
summarizes the incremental costs associated with administering the
upgrades necessary for compliance with today's final rule.
Table 11--Incremental Costs From Replacing Tempered/Tempered Glazing With Laminated/Tempered Glazing and Upgraded Window Latches
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total cost Total cost
Cost for Number of Number of to upgrade assuming
Glazing type Cost per improved side glass Cost per applicable all 47.7%
window latch per positions vehicle vehicles applicable compliance
window vehicles rate
--------------------------------------------------------------------------------------------------------------------------------------------------------
Double-glazed tempered/tempered.............................. $430.62 $0.00 12 $5,167.48 2,200 $11,368,457 NA
Double-glazed laminated/tempered............................. 500.28 0.06 12 6,003.40 2,200 13,209,144 NA
Incremental cost............................................. 69.66 0.06 12 835.92 2,200 1,840,687 963,477
--------------------------------------------------------------------------------------------------------------------------------------------------------
The benefits of today's final rule are calculated based on the
number of expected equivalent lives saved \58\ from ejections during
crashes involving the applicable buses. NHTSA calculated the fatal
target population using FARS data from 2006-2019 and injury data from
NASS-GES (2006-2015) and CRSS (2016-2019). The target population was
estimated using both a 15 percent seat belt usage scenario and a 90
percent seat belt usage scenario based on the 2021 large bus rollover
structural integrity final rule. The resulting target population (i.e.,
unrestrained ejected \59\ occupants) estimated for today's final rule
after accounting for the benefits from the other initiatives applicable
to the same group of buses (seat belts, ESC, and structural integrity)
is 6.38 fatalities at the 15 percent seat belt use rate and 1.18
fatalities at the 90 percent seat belt use rate. Based on the various
rollover tests on buses performed by the agency,
[[Page 86280]]
NHTSA believes that the required advanced glazing would maintain its
retention capability in single and double \1/4\-turn bus rollover
crashes. Accordingly, the agency expects that the requirements would
result in 0.37 to 1.91 equivalent lives saved annually. Table 12 below
summarizes the costs and benefits of today's final rule.
---------------------------------------------------------------------------
\58\ For details concerning equivalent lives saved, reference
the FRE docketed with this final rule.
\59\ For the analysis, both complete and partial ejections are
included as ``ejected occupants'' since the anti-ejection glazing is
expected to reduce the risk of both ejection types.
Table 12--Summary of Annualized Costs and Benefits Due to Advanced Glazing
[Costs are in millions of 2022 dollars]
----------------------------------------------------------------------------------------------------------------
15% belt use rate 90% belt use rate
Discount rate -----------------------------------------------------------------------------------
Undiscounted 3% 7% Undiscounted 3% 7%
----------------------------------------------------------------------------------------------------------------
Equivalent Lives Saved \A\ 1.9191 1.5064 1.1491 0.3740 0.2936 0.2240
\B\........................
Material Costs.............. $0.96 $0.96 $0.96 $0.96 $0.96 $0.96
Cost per Equivalent Lives 0.50 0.64 0.84 2.58 3.28 4.30
Saved......................
Benefits from Comprehensive 24.72 19.40 14.80 4.82 3.78 2.88
Costs Avoided..............
Net Benefits................ 23.75 18.44 13.84 3.85 2.82 1.92
----------------------------------------------------------------------------------------------------------------
Notes:
\A\ These values from the FRE account for serious injuries (MAIS 3-5) by utilizing a relative injury factor.
\B\ MAIS = Maximum AIS, AIS = Abbreviated Injury Scale, MAIS 0 = No Injury, MAIS 1 = Minor, MAIS 2 = Moderate,
MAIS 3 = Serious, MAIS 4 = Severe, MAIS 5 = Critical, MAIS 6 = Maximum (untreatable).
VII. Regulatory Notices and Analyses
E.O. 12866, E.O. 14904, E.O. 13563, and DOT Regulatory Policies and
Procedures
NHTSA has considered the potential impact of this final rule under
E.O. 12866, E.O. 14094, E.O. 13563, DOT Order 2100.6A and the DOT's
regulatory policies and procedures. This final rule is not considered
to be significant under the DOT's regulatory policies and
procedures.\60\
---------------------------------------------------------------------------
\60\ 44 FR 11034 (Feb. 26, 1979).
---------------------------------------------------------------------------
This final rule creates a new FMVSS (FMVSS No. 217a) and makes
several changes to FMVSS No. 217. Specifically, the final rule creates
a new standard that will establish requirements for advanced glazing in
over-the-road buses and buses weighing over 26,000 lb. The final rule
also creates a requirement establishing a minimum protrusion limitation
requirement for emergency exit latches. The agency estimates that
compliance with the final rule would result in an annual cost of $0.96
million to manufacturers. More information on costs can be found in
section VI above.
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 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 13 CFR 121.201, the Small
Business Administration's size standards regulations used to define
small business concerns, manufacturers of the vehicles covered by this
final rule would fall under North American Industry Classification
System (NAICS) No. 336111, Automobile Manufacturing, which has a size
standard of 1,000 employees or fewer. NHTSA estimates that there are 26
manufacturers of these types of vehicles in the United States
(including manufacturers of motorcoaches, cutaway buses, second-stage
motorcoaches, and other types of large buses covered by this final
rule). Using the size standard of 1,000 employees or fewer, we estimate
that approximately 10 of these 26 manufacturers would be considered
small businesses.
The agency does not believe that this final rule will have a
significant economic impact on those small entities. First, the agency
estimates that the incremental costs to each vehicle that currently
does not comply with the requirements would be approximately $836 per
unit to meet the final rule. This incremental cost will not constitute
a significant impact given that the average cost of the vehicles
covered by this final rule ranges from $200,000 to $400,000. Further,
these incremental costs, which are very small compared to the overall
cost of the vehicle, can ultimately be passed on to the purchaser and
user.
In addition, the agency believes that certifying compliance with
the rule will not have a significant impact on the manufacturers. Small
manufacturers have various options available that they may use in
certifying compliance with the standard. Manufacturers are not required
to use NHTSA's test as the basis for their certification. While the
agency's test defined in the regulatory text will be an objective test
capable of determining which vehicles meet the minimum requirements,
manufacturers can use other methods in certifying the compliance of
their own vehicles.
For instance, a manufacturer could obtain advanced glazing windows
from a glazing supplier and test the glazing on body sections of the
vehicle. NHTSA used this approach in its motorcoach side glazing
retention research program. The manufacturer could ``section'' the
vehicle or otherwise obtain a body section representative of the
vehicle, or test the glazing on test frames. It could base its
certification on these tests, without testing a full vehicle.
Unlike NHTSA, manufacturers certifying compliance of its own
vehicles have more detailed information regarding their own vehicles
and can use reasonable engineering analyses to determine whether its
vehicles will comply with the requirements. We believe that a small
manufacturer would be closely familiar with its own vehicle design and
would be able to use modeling and relevant analyses on a vehicle-by-
vehicle basis to reasonably predict whether its design will meet the
requirements of this final rule.
[[Page 86281]]
We also note that the product cycle of the covered buses is
significantly longer than those of other vehicle types. With a longer
product cycle, we believe that the costs of certification for
manufacturers would be further reduced as the costs of conducting
compliance testing and the relevant analyses could be spread over a
significantly longer period of time.
Finally, we note that the requirements in this final rule may
affect the operators of the buses that are the subject of today's final
rule--some of which may be small businesses--but only indirectly as
purchasers of these vehicles. As mentioned above, we anticipate that
the impact on these businesses will not be significant because the
expected price increase of the vehicles (those that do not comply with
the requirements) used by these businesses is small ($836 for each
vehicle valued between $200,000 and $400,000).
For the aforementioned reasons, I hereby certify that this final
rule will not have a significant economic impact on a substantial
number of small entities.
Federalism
NHTSA has examined this final rule pursuant to E.O. 13132 (64 FR
43255; Aug. 10, 1999) and concluded that no additional consultation
with states, local governments, or their representatives is mandated
beyond the rulemaking process. The agency has concluded that the final
rule does not have sufficient federalism implications to warrant
consultation with state and local officials or the preparation of a
federalism summary impact statement. The final rule does not have
``substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government.''
NHTSA rules can have preemptive effect in two ways. First, the
National Traffic and Motor Vehicle Safety Act contains an express
preemption provision: When a motor vehicle safety standard is in effect
under this chapter, a state or a political subdivision of a state may
prescribe or continue in effect a standard applicable to the same
aspect of performance of a motor vehicle or motor vehicle equipment
only if the standard is identical to the standard prescribed under this
chapter. 49 U.S.C. 30103(b)(1). It is this statutory command by
Congress that preempts any non-identical state legislative and
administrative law address the same aspect of performance.
The express preemption provision described above is subject to a
savings clause under which ``[c]ompliance with a motor vehicle safety
standard prescribed under this chapter does not exempt a person from
liability at common law.'' 49 U.S.C. 30103(e). Pursuant to this
provision, state common law tort causes of action against motor vehicle
manufacturers that might otherwise be preempted by the express
preemption provision are generally preserved.
NHTSA rules can also preempt state law if complying with the FMVSS
would render the motor vehicle manufacturers liable under state tort
law. Because most NHTSA standards established by an FMVSS are minimum
standards, a state common law tort cause of action that seeks to impose
a higher standard on motor vehicle manufacturers will generally not be
preempted. However, if and when such a conflict does exist--for
example, when the standard at issue is both a minimum and a maximum
standard--the state common law tort cause of action is impliedly
preempted. See Geier v. American Honda Motor Co., 529 U.S. 861 (2000).
Pursuant to E.O. 13132, NHTSA has considered whether this final
rule could or should preempt state common law causes of action. The
agency's ability to announce its conclusion regarding the preemptive
effect of one of its rules reduces the likelihood that preemption will
be an issue in any subsequent tort litigation. To this end, the agency
has examined the nature (e.g., the language and structure of the
regulatory text) and objectives of this final rule and finds that this
final rule, like many NHTSA rules, prescribes only a minimum safety
standard.
Accordingly, NHTSA does not intend that this final rule preempt
state tort law that would effectively impose a higher standard on motor
vehicle manufacturers than that established by this final rule.
Establishment of a higher standard by means of state tort law would not
conflict with the minimum standard finalized in this document. Without
any conflict, there could not be any implied preemption of a state
common law tort cause of action.
National Environmental Policy Act
NHTSA has analyzed this final rule for the purposes of the National
Environmental Policy Act. The agency has determined that implementation
of this action will 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
Office of Management and Budget (OMB) control number. This rulemaking
will not establish any new information collection requirements.
Unfunded Mandates Reform Act (UMRA)
The Unfunded Mandates Reform Act of 1995 (UMRA) requires federal
agencies to prepare a written assessment of the costs, benefits and
other effects of proposed or final rules that include a federal mandate
likely to result in the expenditure by state, local or tribal
governments, in the aggregate, or by the private sector, of more than
$100 million annually (adjusted annually for inflation, with base year
of 1995). UMRA also requires an agency issuing an NPRM or final rule
subject to the Act to select the ``least costly, most cost-effective or
least burdensome alternative that achieves the objectives of the
rule.'' This final rule would not result in a federal mandate that will
likely 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 annually for inflation, with base year of 1995).
E.O. 12778 (Civil Justice Reform)
When promulgating a regulation, agencies are required under E.O.
12988 to make every reasonable effort to ensure that the regulation, as
appropriate: (1) specifies in clear language the preemptive effect; (2)
specifies in clear language the effect on existing federal law or
regulation, including all provisions repealed, circumscribed,
displaced, impaired, or modified; (3) provides a clear legal standard
for affected conduct rather than a general standard, while promoting
simplification and burden reduction; (4) specifies in clear language
the retroactive effect; (5) specifies whether administrative
proceedings are to be required before parties may file suit in court;
(6) explicitly or implicitly defines key terms; and (7) addresses other
important issues affecting clarity and general draftsmanship of
regulations.
Pursuant to this Order, NHTSA notes as follows. The preemptive
effect of this final rule is discussed above. NHTSA notes further that
there is no requirement that an individual submit a petition for
reconsideration or pursue
[[Page 86282]]
other administrative proceedings before they may file suit in court.
National Technology Transfer and Advancement Act
Under the National Technology Transfer and Advancement Act of 1995
(NTTAA) (Pub. L. 104-113), all federal agencies and departments shall
use technical standards that are developed or adopted by voluntary
consensus standards bodies, using such technical standards as a means
to carry out policy objectives or activities determined by the agencies
and departments. Voluntary consensus standards are technical standards
(e.g., materials specifications, test methods, sampling procedures, and
business practices) that are developed or adopted by voluntary
consensus standards bodies, such as the International Organization for
Standardization and the Society of Automotive Engineers. The NTTAA
directs us to provide Congress, through OMB, explanations when we
decide not to use available and applicable voluntary consensus
standards. There are no voluntary consensus standards developed by
voluntary consensus standards bodies pertaining to this final rule.
Plain Language Requirement
E.O. 12866 requires each agency to write all rules in plain
language. Application of the principles of plain language includes
consideration of the following questions:
Have we organized the material to suit the public's needs?
Are the requirements in the rule clearly stated?
Does the rule contain technical language or jargon that
isn't clear?
Would a different format (grouping and order of sections,
use of headings, paragraphing) make the rule easier to understand?
Would more (but shorter) sections be better?
Could we improve clarity by adding tables, lists, or
diagrams?
What else could we do to make the rule easier to
understand?
NHTSA has considered these questions and attempted to use plain
language in promulgating this final rule. If readers have suggestions
on how we can improve our use of plain language, please write us.
Regulatory Identifier Number (RIN)
The DOT assigns a 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. The RIN contained in the heading at the beginning of this
notice may be used to find this action in the Unified Agenda.
Privacy Act
In accordance with 5 U.S.C. 553(c), DOT solicits comments from the
public to better inform its decision-making process. DOT posts these
comments, without edit, including any personal information the
commenter provides, to www.regulations.gov, as described in the system
of records notice (DOT/ALL-14 FDMS), which can be reviewed at
www.transportation.gov/privacy. 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 Statement in the Federal
Register published on April 11, 2000 (Volume 65, Number 70; Pages
19477-78).
List of Subjects in 49 CFR Part 571
Imports, motor vehicles, motor vehicle safety.
Amended Regulatory Text
In consideration of the foregoing, NHTSA amends 49 CFR part 571 as
follows:
PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS
0
1. The authority citation for part 571 continues to read as follows:
Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166;
delegation of authority at 49 CFR 1.95.
0
2. Section 571.217 is amended by
0
a. In paragraph S.4 removing the definition of ``Daylight opening'';,
and
0
b. Adding paragraph S5.4.4 to read as follows:
Sec. 571.217 Standard No. 217; Bus emergency exits and window
retention and release.
* * * * *
S5.4.4 Protrusion Limit on Emergency Exit Window Latches and other
related mechanisms
For buses applicable under S3 of this standard, manufactured on or
after October 30, 2027, any emergency exit window latch and other
related release mechanisms shall not protrude more than 25 mm (1 inch)
into the opening of the emergency exit window when that window is in
the open position as described under S5.4.1 and S5.4.2.
* * * * *
0
3. Section 571.217a is added to read as follows:
Sec. 571.217a Standard No. 217a; Anti-ejection glazing for bus
portals; Mandatory applicability beginning October 30, 2027.
S1. Scope. This standard establishes requirements to improve side
and roof bus portals by way of glazing that is highly resistant to
partial or complete occupant ejection in all types of crashes.
S2. Purpose. The purpose of this standard is to reduce death and
injuries resulting from complete and partial ejections of bus occupants
through side and roof portals during rollovers and other crashes.
S3. Application.
(a) Subject to S3(b) of this section, this standard applies to:
(1) Over-the-road buses manufactured on or after October 30, 2027,
and
(2) Buses, other than over-the-road buses, that have a gross
vehicle weight rating (GVWR) greater than 11,793 kilograms (kg)
manufactured on or after October 30, 2027.
(b) This standard does not apply to school buses, transit buses,
prison buses, and perimeter-seating buses.
S4. Definitions.
Daylight opening means, for openings on the side of the vehicle
(other than a door opening), the locus of all points where a horizontal
line, perpendicular to the vehicle longitudinal centerline, is tangent
to the periphery of the opening. For openings on the roof of the
vehicle, daylight opening means the locus of all points where a
vertical line is tangent to the periphery of the opening. The periphery
includes surfaces 100 millimeters (mm) inboard of the inside surface of
the window glazing and 25 mm outboard of the outside surface of the
window glazing. The periphery excludes the following: Any flexible
gasket material or weather stripping used to create a waterproof seal
between the glazing and the vehicle interior; grab handles used to
facilitate occupant egress and ingress; and any part of a seat.
Over-the-road bus means a bus characterized by an elevated
passenger deck located over a baggage compartment.
Perimeter-seating bus means a bus with 7 or fewer designated
seating positions rearward of the driver's seating position that are
forward-facing or can convert to forward-facing without the use of
tools.
Portal means an opening that could, in the event of a crash
involving the vehicle, permit the partial or complete ejection of an
occupant from the vehicle, including a young child.
Prison bus means a bus manufactured for the purpose of transporting
persons subject to involuntary restraint or
[[Page 86283]]
confinement and has design features consistent with that purpose.
Stop-request system means a vehicle-integrated system for passenger
use to signal to a vehicle operator that they are requesting a stop.
Transit bus means a bus that is equipped with a stop-request system
sold for public transportation provided by, or on behalf of, a Federal,
State, or local government and that is not an over-the-road bus.
S5. Requirements. When tested according to the procedures specified
in S6 of this section and under the conditions specified in paragraph
S7 of this section, each applicable bus shall meet the following
requirements specified in this section. The requirements of this
paragraph S5 n do not apply to portals other than side and roof
portals, and do not apply to a side or roof portal whose minimum
surface dimension measured through the center of its area is less than
279 mm.
S5.1 Edge impact.
(a) When the ejection impactor described in S8 of this section
contacts the target location specified in S6.1.1 of this section of
each side or roof daylight opening of a vehicle at 21.6 km/h 0.4 km/h, no portion of the window (excluding glazing shards)
may pass the ejection reference plane defined under the procedures of
S6 of this section.
(b) Each piece of window glazing and each surrounding window frame
shall be retained by its surrounding structure in a manner that
prevents the formation of any opening large enough to admit the
complete passage of a 102 mm diameter sphere when a force of no more
than 22 newtons (N) is applied with the sphere at any vector in a
direction from the interior to the exterior of the vehicle.
S5.2 Center impact.
(a) When the ejection impactor described in paragraph S8 of this
section contacts the target location specified in paragraph S6.1.2 of
this section of each side or roof daylight opening of a vehicle at 21.6
km/h 0.4 km/h, no portion of the window (excluding glazing
shards) may pass the ejection reference plane defined under the
procedures of paragraph S6.3 of this section.
(b) Each piece of window glazing and each surrounding window frame
shall be retained by its surrounding structure in a manner that
prevents the formation of any opening large enough to admit the
complete passage of a 102 mm diameter sphere when a force of no more
than 22 N is applied with the sphere at any vector in a direction from
the interior to the exterior of the vehicle.
S5.3 Center impact to pre-broken glazing.
(a) When the ejection impactor described in S8 of this section
contacts the target location specified in S6.1.3 of this section of
each side or roof daylight opening of a vehicle at 21.6 km/h 0.4 km/h, no portion of the impactor may displace more than 175
mm past where the surface of the glazing had been in an unbroken
condition.
(b) Each piece of window glazing and each surrounding window frame
shall be retained by its surrounding structure in a manner that
prevents the formation of any opening large enough to admit the
complete passage of a 102 mm diameter sphere when a force of no more
than 22 N is applied with the sphere at any vector in a direction from
the interior to the exterior of the vehicle.
S5.4 Post-Impact Emergency Exit Release and Operability.
After the impacts described in paragraphs S5.1, S5.2, and S5.3 of
this section, each emergency exit provided in accordance with Standard
No. 217 (Sec. 571.217) shall be capable of releasing and opening
according to the requirements specified in that standard.
S6. Test procedures.
S6.1 Target locations.
S6.1.1 Edge impact. Position the impactor face on the glazing
adjacent to a latch or discrete attachment point such that, when viewed
perpendicular to the glazing surface, the center of the impactor face
plate is as close as practicable to the center of the latch attachment
point or discrete attachment point with the impactor face plate either
horizontal or vertical, whichever orientation provides the shortest
distance between the two centers, while maintaining at least a 25 mm
2 mm distance between the impactor face plate edge and the
window frame. ``Window frame'' includes latches, handles, attachments,
and any solid structures other than the glazing material or flexible
gaskets. If the window does not have any latches or discrete attachment
points (e.g., it is fully rubber bonded or glued), position the
impactor as follows:
(a) For side windows, directly above the center of the lower window
edge, with the impactor face plate either horizontal or vertical,
whichever orientation provides the shortest distance between the two
centers, with the bottom edge of the impactor face plate 25 mm 2 mm above the daylight opening periphery when viewed
perpendicular to the glazing surface.
(b) For roof glazing panels or roof windows, directly forward of
the center of the rearmost window edge, with the impactor face plate
either horizontal or vertical, whichever orientation provides the
shortest distance between the two centers, with the rearmost edge of
the impactor face plate 25 mm 2 mm forward of the daylight
opening periphery when viewed perpendicular to the glazing surface.
S6.1.2 Center impact.
Position the center of the impactor face, with the long axis of the
impactor face plate either vertical or horizontal, at the center of the
daylight opening area of the window with the glazing intact.
S6.1.3 Center impact to pre-broken glazing.
Position the center of the impactor face, with the long axis of the
impactor face plate either vertical or horizontal, at the center of the
daylight opening area of the window with the glazing pre-broken
following the procedure in paragraphs S6.2.1 and S6.2.2 of this
section.
S6.2 Window glazing pre-breaking procedure.
S6.2.1 Breakage pattern. Locate the geometric center of the
daylight opening. Mark the surface of the window glazing in a
horizontal and vertical grid of points separated by 75 mm
2 mm with one point coincident within 2 mm of the
geometric center of the daylight opening (Figure 2).
(a) If the window is a single-pane unit, then both the occupant
space interior and outside exterior surfaces of the glass pane are
marked with the 75 mm grid pre-break pattern. The patterns are offset
diagonally from one another (the points on one surface of the glass
pane are offset 37.5 mm 2 mm horizontally and 37.5 mm
2 mm vertically from the points on the contralateral
surface of the glass pane).
(b) If the window is an insulated unit or double-glazed window,
then both the occupant space side of the interior pane and the outside
of the exterior pane are marked with the 75 mm grid prebreak pattern.
(1) If one of the glass panes is constructed of tempered or
toughened glass, the insulated surface of the remaining glass pane
(within the air gap) is marked with the 75 mm grid pre-break pattern.
The patterns are offset diagonally from the remaining glass pane's
contralateral surface.
(2) If neither pane is tempered glass, then both the occupant space
side of the interior pane and the outside of the exterior pane are
marked with the 75 mm grid pre-break pattern. The patterns are not
diagonally offset from one another. The insulated surfaces of the glass
panes (within the air gap) are not marked.
S6.2.2 Breakage method.
[[Page 86284]]
(a) Use a 100 mm 10 mm x 100 mm 10 mm
piece of rigid material as a reaction surface on the opposite side of
the glazing to prevent to the extent possible the window surface from
deforming by more than 10 mm when pressure is being applied by the
staple gun.
(b) Start with the inside surface of the window and forwardmost,
lowest mark made as specified in S6.2.1 of this section. Use an
electric staple gun without any staples to apply a load along a line of
12 to 14 mm onto the glazing. The applied force shall be 4,200 N 850 N. Apply the line load only once at each marked location,
even if the glazing does not break or no perceptible mark or hole
results.
(c) Continue applying the line load with the electric staple gun by
moving rearward in the grid until the end of a row is reached. Then
move to the forwardmost mark on the next higher row and apply the line
load. Continue in this pattern until the line load has been applied to
all grid points on the inside surface of the glazing.
(d) Repeat the process on the outside surface of the window.
(e) If applying the line load causes the glazing to disintegrate,
halt the breakage procedure and proceed with the next step in the
compliance test.
S6.3 Determination of ejection reference planes.
(a) For side windows, the ``ejection reference plane'' is a
vertical plane parallel to the longitudinal vertical center plane of
the bus passing through a point located at a lateral distance of 102 mm
from the lateral most point on the glazing and surrounding frame, with
the window in the closed position.
(b) For roof glazing panels/windows, the ``ejection reference
plane'' is a horizontal plane passing through a point located at a
vertical distance of 102 mm from the highest point on the glazing and
surrounding frame, with the window/panel in the closed position.
S7. Test conditions.
During testing, the ambient temperature is between 18 degrees C.
and 29 degrees C., at any relative humidity between 10 percent and 70
percent.
S8. Guided impactor.
The impactor test device has the dimensions shown in Figure 1 of
this section. It has a total impactor mass of 26 kg 1.0 kg
and a spring stiffness of 258 N/mm 39 N/mm. The impactor
is propelled in the horizontal direction in impacts to the side
daylight openings and is propelled vertically in impacts to the roof
daylight openings.
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[GRAPHIC] [TIFF OMITTED] TR30OC24.019
Issued in Washington, DC, under authority delegated in 49 CFR
1.95 and 501.5.
Sophie Shulman,
Deputy Administrator.
[FR Doc. 2024-24462 Filed 10-29-24; 8:45 am]
BILLING CODE 4910-59-P