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Rule2021-27538

Federal Motor Vehicle Safety Standards; Bus Rollover Structural Integrity

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Published

December 29, 2021

Effective

December 30, 2024

Issuing agencies

Transportation DepartmentNational Highway Traffic Safety Administration

Abstract

NHTSA is issuing this final rule to establish Federal Motor Vehicle Safety Standard (FMVSS) No. 227, "Bus rollover structural integrity," to enhance the rollover structural integrity of over-the- road buses (motorcoaches), and other buses with a gross vehicle weight rating (GVWR) greater than 11,793 kilograms (kg) (26,000 pounds (lb)). This final rule, issued pursuant to the Moving Ahead for Progress in the 21st Century Act (MAP-21), requires the buses to provide a "survival space" in a rollover test to protect occupants from possible collapse of the bus structure around them. In addition, to reduce the likelihood of ejection, this final rule prohibits emergency exits from opening in the rollover test. This final rule ensures that bus roofs and side wall panels will resist deformation and intrusion into the occupant space in rollover crashes, and reduces the risk of emergency exits becoming ejection portals in a crash.

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[Federal Register Volume 86, Number 247 (Wednesday, December 29, 2021)]
[Rules and Regulations]
[Pages 74270-74307]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-27538]

[[Page 74269]]

Vol. 86

Wednesday,

No. 247

December 29, 2021

Part III

Department of Transportation

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National Highway Traffic Safety Administration

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49 CFR Part 571

Federal Motor Vehicle Safety Standards; Bus Rollover Structural
Integrity; Final Rule

Federal Register / Vol. 86 , No. 247 / Wednesday, December 29, 2021 /
Rules and Regulations

[[Page 74270]]

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. NHTSA-2021-0088]
RIN 2127-AK96

Federal Motor Vehicle Safety Standards; Bus Rollover Structural
Integrity

AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation (DOT).

ACTION: Final rule.

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SUMMARY: NHTSA is issuing this final rule to establish Federal Motor
Vehicle Safety Standard (FMVSS) No. 227, ``Bus rollover structural
integrity,'' to enhance the rollover structural integrity of over-the-
road buses (motorcoaches), and other buses with a gross vehicle weight
rating (GVWR) greater than 11,793 kilograms (kg) (26,000 pounds (lb)).
This final rule, issued pursuant to the Moving Ahead for Progress in
the 21st Century Act (MAP-21), requires the buses to provide a
``survival space'' in a rollover test to protect occupants from
possible collapse of the bus structure around them. In addition, to
reduce the likelihood of ejection, this final rule prohibits emergency
exits from opening in the rollover test. This final rule ensures that
bus roofs and side wall panels will resist deformation and intrusion
into the occupant space in rollover crashes, and reduces the risk of
emergency exits becoming ejection portals in a crash.

DATES: The effective date of this final rule is: December 30, 2024.
Optional early compliance is permitted.
Petitions for reconsideration: Petitions for reconsideration of
this final rule must be received not later than February 14, 2022.

ADDRESSES: Petitions for reconsideration of this final rule must refer
to the docket 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 <a href="https://www.regulations.gov">https://www.regulations.gov</a>,
including any personal information provided.
Privacy Act: Please see the Privacy Act heading under Rulemaking
Analyses and Notices.

FOR FURTHER INFORMATION CONTACT: For non-legal issues, you may contact
James Myers, NHTSA Office of Crashworthiness Standards, telephone 202-
493-0031, fax 202-493-2990. For legal issues: Deirdre Fujita, NHTSA
Office of Chief Counsel, telephone 202-366-2992, fax 202-366-3820.
Address: National Highway Traffic Safety Administration, U.S.
Department of Transportation, 1200 New Jersey Avenue SE, West Building,
Washington, DC 20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary
a. Introduction
b. How This Final Rule Differs From the Notice of Proposed
Rulemaking
c. NTSB Recommendations
d. Costs and Benefits
e. NHTSA's Determination of MAP-21 Requirements and
Considerations
f. Retrofitting
II. Introduction
III. NHTSA's Statutory Authority
a. National Traffic and Motor Vehicle Safety Act (Safety Act)
b. MAP-21 (The Motorcoach Enhanced Safety Act of 2012)
IV. Safety Need (FARS 2004-2018 Data Analysis)
V. Summary of the NPRM
VI. High Level Summary of the Comments
VII. Scope and Purpose of the Rule
VIII. Applicability of the Rule
a. Medium-Size Buses (Buses With a GVWR of 4,536 to 11,793 kg
(10,000-26,000 lb))
b. Large Buses
IX. School Bus Derivative Buses
X. Performance Requirements
a. Severity of the Rollover Test
b. Intrusion Into the Survival Space
c. Luggage Racks and Seat Anchorages
d. Emergency Exits
XI. Glazing Issues
a. Side Glazing on the Non-Struck Side of the Bus
b. Type of Glazing
c. Moon Roofs
d. Struck-Side Window Evaluations
XII. Test Procedure Issues
a. Ballasting the Vehicle
b. Vehicle Fluids
c. Additional Tools for Survival Space Evaluation During Testing
XIII. Other Issues
a. ECE R.66 Alternative Compliance Methods
b. Regulatory Alternatives
1. FMVSS No. 216
2. FMVSS No. 220
c. Additional MAP-21 Considerations
XIV. Lead Time
XV. Retrofitting Used Buses
XVI. Overview of Costs and Benefits
XVII. Rulemaking Analyses and Notices

I. Executive Summary

a. Introduction

This final rule substantially improves motorcoach safety. It
establishes an FMVSS to improve the resistance of motorcoach roofs and
side wall panels to deformation and intrusion into the occupant
compartment in rollover crashes, and fulfills a mandate in section
32703(b)(1) of MAP-21. This final rule also accords with section
32703(b)(2) of MAP-21 by requiring emergency exits to remain closed in
a rollover to prevent partial and complete ejection of passengers.
This final rule achieves longstanding NHTSA and Departmental goals
to enhance motorcoach safety. NHTSA identified four priority areas in
which to improve the safety of motorcoaches and other large buses:
Requiring passenger seat belts, improved rollover structural integrity,
improved emergency evacuation, and fire safety.\1\ With this final
rule, NHTSA has completed research and rulemaking on the first two
priority areas and completed research on the other two.
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\1\ See ``NHTSA's Approach to Motorcoach Safety,'' Docket No.
NHTSA-2007-28793. In NHTSA's plan, ``motorcoach'' referred to inter-
city transport buses. 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, <a href="https://www.fmcsa.dot.gov/sites/fmcsa.dot.gov/files/docs/Motorcoach-Safety-Action-Plan-2012.pdf">https://www.fmcsa.dot.gov/sites/fmcsa.dot.gov/files/docs/Motorcoach-Safety-Action-Plan-2012.pdf</a>. This final rule is an action included in the
Departmental plan.
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Congress also focused on these and other areas in incorporating the
Motorcoach Enhanced Safety Act of 2012 into MAP-21 (Pub. L. 112-141).
Among other matters, MAP-21 directed NHTSA (as delegated by the
Secretary of Transportation) to require seat belts in ``motorcoaches,''
a term, Congress stated, that has the same meaning given the term
``over-the-road bus'' in section 3038(a)(3) of the Transportation
Equity Act for the 21st Century (49 U.S.C. 5310 note). An over-the-road
bus (OTRB) is a bus characterized by an elevated passenger deck located
over a baggage compartment.\2\ NHTSA has used the term ``over-the-road
bus'' in the FMVSSs issued pursuant to the MAP-21 mandates. For
example, NHTSA fulfilled MAP-21's seat belt mandate by amending FMVSS
No. 208, ``Occupant crash protection,'' to require seat belts in each
passenger seating position in OTRBs, as well as in other buses that are
not OTRBs (non-OTRBs) with a GVWR greater than 11,793 kg (26,000
lb).\3\ (For the convenience of the reader, NHTSA uses the term ``large
buses'' in this final rule to refer to OTRBs regardless of GVWR and
non-OTRBs with a GVWR

[[Page 74271]]

greater than 11,793 kg (26,000 lb), with some exceptions.)
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\2\ Under section 32701(6) of the Motorcoach Enhanced Safety
Act, ``motorcoach'' does not include a bus used in public
transportation provided by, or on behalf of, a public transportation
agency, or a school bus.
\3\ 78 FR 70416, November 25, 2013; denial of petitions for
reconsideration, 81 FR 19902, April 6, 2016.
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Section 32703(b)(1) of MAP-21 also directed NHTSA to pursue
rulemaking for OTRBs to establish improved roof and roof support
standards that substantially improve the resistance of bus roofs to
deformation and intrusion in rollovers. 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.\4\ As
discussed in this final rule, NHTSA has made such a determination
regarding an FMVSS for all large buses.
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\4\ MAP-21, section 32703(b) and (b)(1)).
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This final rule complements the November 2013 seat belt rule. With
all new large buses manufactured since 2016 required to have lap and
shoulder seat belts for passengers, increasing numbers of passengers
can be belted. This final rule establishing FMVSS No. 227 will ensure
that these belted passengers will be significantly protected against
unreasonable risk of injury in frontal crashes and significantly
protected against the risk of ejection in rollovers. Hand-in-hand with
the seat belt rule, this final rule enhances the safety of these belted
passengers by providing a ``survival space'' in a rollover, a space
where the belted occupants are protected from intruding structures such
as a collapsing roof or a detached luggage rack. The new standard's
improvements to the roof and sidewall strength of the buses will also
protect unbelted occupants against structural failure of the bus
compartment. This final rule improves transportation safety for the
most vulnerable in our society since more than half of motorcoach trips
are made by children and senior citizens.\5\ It furthers transportation
equity by providing the same occupant crash protection to these
passengers as the protection provided to occupants of other passenger
motor vehicles,\6\ by reducing deaths and injuries due to the crushing
of the roof into the occupant compartment in rollover crashes.
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\5\ ``Motorcoach Census 2013, A Study of the Size and Activity
of the Motorcoach Industry in the United States and Canada in
2012,'' American Bus Association Foundation, February 27, 2014.
\6\ Passenger vehicles under 4,536 kg (10,000 lb) GVWR are
subject to the requirements of FMVSS No. 216, ``Roof crush
resistance; Applicable unless a vehicle is certified to Sec.
216a,'' or to FMVSS No. 216a, ``Roof crush resistance, Upgraded
standard.''
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This final rule applies to all new large buses, with limited
exceptions. The standard does not apply to school buses, prison buses,
buses with perimeter seating, or to transit buses that are not OTRBs.
School buses already meet an FMVSS for roof strength, which is FMVSS
No. 220, ``School bus rollover protection'' (49 CFR 571.220). In
response to comments, NHTSA has also decided not to apply the standard
to ``school bus derivative buses,'' which this final rule defines as
buses built on a school bus platform. These vehicles may not have
school bus lights and stop arms meeting FMVSS No. 108 and No. 131,
respectively, or seating systems meeting FMVSS No. 222, ``School bus
seating and passenger protection,'' but the buses have safety systems
that are otherwise identical to school buses regarding their emergency
exits, rollover protection (FMVSS No. 220), bus body joint strength,
and fuel system integrity. The vehicles could be certified as meeting
the FMVSSs for ``school buses'' if they had school bus lights meeting
FMVSS No. 108, stop arms meeting FMVSS No. 131, and seating systems
meeting FMVSS No. 222. Because school bus derivative buses already meet
the roof crush resistance requirements in FMVSS No. 220, it would be
redundant to require the buses to meet Standard No. 227 established by
this final rule.
The test for the large buses adopted by this final rule is the
complete vehicle rollover test of United Nations Economic Commission
for Europe (ECE) Regulation 66, ``Uniform Technical Prescriptions
Concerning the Approval for Large Passenger Vehicles with Regard to the
Strength of their Superstructure,'' (ECE R.66).\7\ The test simulates a
real-world rollover crash of a large bus. The test bus is placed on a
tilting platform that is 800 mm (24 inches) above a smooth and level
concrete surface. One side of the tilting platform along the length of
the bus is raised at a steady rate of not more than 5 degrees/second
until the vehicle becomes unstable, rolls off the platform, and impacts
the concrete surface below. Some commenters to the August 6, 2014
notice of proposed rulemaking (NPRM) (79 FR 46090) thought that the
test was too lenient, but NHTSA believes that those views are mistaken.
As explained in this preamble, this test imparts severe crash forces
that the buses must resist. FMVSS No. 227 prohibits any intrusion into
the ``survival space'' by any part of the vehicle outside the survival
space, except for minute objects weighing less than 15.0 grams, such as
pebbles of glazing, or bolts and screws, which do not pose an
unreasonable risk to safety for occupants.
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\7\ Dated February 2006, <a href="https://live.unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/r066r1e.pdf">https://live.unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/r066r1e.pdf</a>. ECE R.66 defines
``superstructure'' as ``the load-bearing components of the bodywork
as defined by the manufacturer, containing those coherent parts and
elements which contribute to the strength and energy absorbing
capability of the bodywork, and preserve the residual space in the
rollover test.'' ``Bodywork'' means ``the complete structure of the
vehicle in running order, including all the structural elements
which form the passenger compartment, driver's compartment, baggage
compartment and spaces for the mechanical units and components.''
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The ``survival space'' requirement ensures at least a minimum level
of structural integrity for the buses by prohibiting intrusions into
the occupant space that can cause harm. It establishes ``improved roof
and roof support standards'' that substantially improve the resistance
of the roof to deformation and intrusion, in accordance with MAP-21. It
ensures that buses are constructed so that structures outside of the
survival space, such as luggage racks and large pieces of glazing, do
not enter the survival space in the rollover.
The requirement that emergency exits remain shut during and after
the rollover test reduces the likelihood of emergency exits becoming
ejection portals during rollovers, which is a goal consistent with MAP-
21. Section 32703(b)(2) of MAP-21 requires NHTSA to consider requiring
advanced glazing \8\ standards for each motorcoach portal and ``other
portal improvements to prevent partial and complete ejection of
motorcoach passengers, including children.'' In NHTSA's motorcoach
tests conducted during development of this rulemaking, roof and side
emergency exits opened during the rollover event and the panes of
advanced glazing popped out of their mounting. The requirement that
emergency exits remain closed is a ``portal improvement'' established
pursuant to section 32703(b)(2). Additionally, the requirement that the
glazing panels not intrude into the survival space by detaching from
the non-struck side of the bus will ensure the glazing panels remain
intact in their mounting during bus rollover crashes and not form
ejection portals.\9\
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\8\ MAP-21 (section 32702(1)) defines ``advanced glazing'' as
``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.'')
\9\ On May 6, 2016 (81 FR 27904), NHTSA issued an NPRM proposing
to establish FMVSS No. 217a to improve glazing materials used in
motorcoaches and other large buses. The NPRM proposed an impactor
test of glazing material to simulate the loading from an average
size adult male impacting a window on the opposite side of a large
bus in a rollover. Countermeasures used to meet the test would
likely involve the use of advanced glazing. This final rule adopting
FMVSS No. 227 would complement FMVSS No. 217a by improving the
securement of the advanced glazing in the buses.

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[[Page 74272]]

b. How This Final Rule Differs From the Notice of Proposed Rulemaking
(NPRM)

The most noteworthy differences between this final rule and the
NPRM \10\ are highlighted below.
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\10\ NPRM, August 6, 2014 (79 FR 46090).
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1. This final rule adopts the NPRM's proposed ECE R.66 full vehicle
test to improve the roof and structural integrity of OTRBs (except for
a few buses with unique configurations), and non-OTRBs with a GVWR
greater than 11,793 kg (26,000 lb)). The agency proposed to exclude
non-OTRBs with perimeter seating from the standard. After evaluation of
the comments received, this final rule excludes all perimeter seating
buses, as there is not a sufficient reason to distinguish between buses
just based on the location of a luggage compartment. Further, all
prison buses are excluded due to the unique interior configuration of
the buses, as are school bus derived buses, as the latter vehicles
already meet NHTSA's school bus roof crush resistance standard.
2. This final rule adopts the NPRM's proposed prohibition that no
part of the bus that is outside the survival space shall intrude into
the survival space, both during movement of the tilting platform or
resulting from impact of the bus on the impact surface. However, given
the high force applications imparted to the bus structure in the
rollover test, this final rule permits debris caused by the impact to
fall into the survival space, such as small glazing pebbles or bolts
and screws. The objects must not weigh more than 15.0 grams.
3. This final rule does not adopt the NPRM's proposal that each
anchorage of an interior overhead luggage rack or other compartment
must not completely separate from its mounting structure during
movement of the tilting platform or resulting from impact of the bus on
the impact surface. This final rule also does not adopt the NPRM's
proposal that seat anchorages must not become dislodged during the
test. Under the NPRM, those proposed prohibitions would have applied
even if the luggage rack does not enter the survival space, or the seat
anchorages dislodged within the survival space. NHTSA has decided that
the primary purpose of this rulemaking is to establish a roof strength
and crush resistance standard that improves the resistance of roofs to
deformation and intrusion, i.e., by providing a survival space to
occupants in rollovers. The purpose is achieved by prohibiting any
structure, such as overhead luggage racks, from intruding into the
survival space. By prohibiting overhead luggage racks from impeding
into the survival space in the rollover, overhead luggage racks will
have to be better anchored to the bus wall than they had in the past so
that they do not detach and intrude into the survival space in the
test. Thus, the proposed luggage rack provision is not needed to ensure
that a survival space is provided since luggage racks are prohibited
from intruding on the survival space. Similarly, the proposed seat
anchorage provision is not necessary to achieve a survival space for
occupants.
4. This final rule does not adopt the proposed provision that each
side window glazing opposite the impacted side of the vehicle must
remain attached to its mounting structure so as not to allow the
passage of a 102 mm (5-inch) diameter sphere. The sphere test was
proposed to ensure that, after the rollover test, the glazing remain
firmly attached to its mounting. Because the primary purpose of this
rulemaking is to provide a necessary survival space to occupants in
rollovers, the purpose is achieved by prohibiting panes of glazing from
falling into the survival space. The proposed requirement that the
glazing not form openings is not germane to the survival space
specification and unnecessarily complicates this rulemaking.
These changes and others are discussed in this preamble.

c. NTSB Recommendations

This final rule accords with the following National Transportation
Safety Board (NTSB) recommendations that NTSB issued to NHTSA to
improve motorcoach safety.
In an NTSB Highway Special Investigation Report (1999), Bus
Crashworthiness Issues,\11\ NTSB cited an October 1971 rollover of a
1970 Motor Coach Industries (MCI) bus as justification for the
following recommendations:
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\11\ National Transportation Safety Board. 1999, Bus
Crashworthiness Issues. Highway Special Investigation Report NTSB/
SIR-99/04. Washington, DC.
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``H-99-50 (MW): In 2 years, issue performance standards for
motorcoach roof strength that provide maximum survival space for all
seating positions and that take into account current typical motorcoach
window dimensions.''
``H-99-51: Once performance standards have been developed for
motorcoach roof strength, require newly manufactured motorcoaches to
meet those standards.''
In November 2009, after investigating an August 2008 Sherman, Texas
bus crash,\12\ the NTSB issued two safety recommendations. In this
rollover crash, the failure of the overhead luggage rack on the vehicle
impeded passenger egress and rescue efforts. Thus, NTSB stated that the
Sherman accident and NHTSA's motorcoach testing indicate that the lack
of standards for overhead luggage racks on motorcoaches leaves
passengers at risk of serious injury from interaction with overhead
luggage racks in a crash and made the following recommendations:
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\12\ NTSB/HAR-09/02 PB2009-916202; Motorcoach Run-Off-the-Bridge
and Rollover Sherman, Texas August 8, 2008; October 2009; <a href="https://www.ntsb.gov/investigations/AccidentReports/Reports/HAR0902.pdf">https://www.ntsb.gov/investigations/AccidentReports/Reports/HAR0902.pdf</a>,
last accessed 09/08/2021.
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``H-09-23: Develop performance standards for newly manufactured
motorcoaches to require that overhead luggage racks remain anchored
during an accident sequence.''
``H-09-24: Develop performance standards for newly manufactured
motorcoaches that prevent head and neck injuries from overhead luggage
racks.''
This final rule is consistent with the above NTSB recommendations.
NHTSA is issuing performance standards for motorcoach roof strength
that provide a survival space for all seating positions and is
requiring new motorcoaches to meet those requirements. The standard
established by this final rule requires that overhead luggage racks
remain anchored during a rollover such that they do not enter the
requisite survival space and injure passengers in the survival space.

d. Costs and Benefits

NHTSA has examined the benefits and costs of this final rule to
ensure that the agency adopts only those amendments that contribute to
improved safety and that are consistent with the directives of MAP-21
and the principles for regulatory decision-making set forth in
Executive Order 12866, Regulatory Planning and Review. Over the 15-year
period between 2004 and 2018, on average 22 fatalities occurred
annually to occupants of these buses. Though a relatively small
percentage of overall traffic fatalities, data show that rollover
crashes are particularly deadly for large buses. Among the 122 fatal
crashes, 56 were rollover crashes resulting in 189 fatalities. This
final rule enhances passenger protection in rollover crashes in a
reasonable and achievable way. As discussed in the next section, NHTSA
adopts this final rule because a rollover structural integrity standard
meets the requirements and considerations in

[[Page 74273]]

subsections (a) and (b) of section 30111 of the Safety Act. This rule
provides safety to passengers in a reasonable, objective, and cost-
effective manner while harmonizing the standard internationally.
NHTSA has determined this rulemaking to be cost beneficial.\13\
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\13\ NHTSA has developed a Final Regulatory Evaluation (FRE)
that discusses issues relating to the potential costs, benefits and
other impacts of this regulatory action. The FRE is available in the
docket for this final rule and may be obtained by downloading it or
by contacting Docket Management at the address or telephone number
provided at the beginning of this document.
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The agency estimates the annual cost of this final rule to be
between $4.81 million and $11.84 million (see Table 1 below). The
countermeasures may include stronger roof structure, support pillars,
side walls, shock resistant latches for emergency exits, and improved
window mounting, resulting in material costs for each bus covered under
this final rule ranging from $325 to $591. We estimate the total weight
increase will range from 181 to 356 kilograms (kg) (399 to 784 pounds
(lb)) for each of these buses and cost an additional $1,862 to $4,790
in fuel per vehicle over the lifetime of the vehicle.
We estimated the benefits of this rule taking into account the
benefits attributable to the agency's final rules on seat belts and
electronic stability control (ESC), as those rules also applied to this
universe of vehicles. We estimate that requiring the subject buses to
meet the rollover structural integrity performance criteria will save
approximately 2-3 lives annually. In addition, we expect that the rule
will reduce the number of seriously injured occupants by 4 annually.
Thus, we estimate that approximately 3.12 equivalent lives are saved
annually if 15 percent of occupants use seat belts, and approximately
2.45 equivalent lives are saved annually (undiscounted) if 90 percent
of occupants use seat belts (see Table 2 below).
The cost per equivalent life saved is estimated to be $2.48 million
to $4.99 million when belt use is estimated to be 15 percent, and $3.17
million to $6.38 million when belt use is estimated to be 90 percent
(see Table 3 below). The net cost/benefit impact ranges from a net
benefit of $13.09 million to $23.31 million if seat belt usage is 15
percent. If the seat belt usage rate is 90 percent, the estimated net
cost/benefit impact ranges from a net benefit of $8.25 million to a net
benefit of $16.97 million (see Table 4 below). While the cost and
benefits of this rule will vary depending on the material/fuel costs
per vehicle and on the belt use rate, per all available information
this final rule will be cost beneficial.

Table 1--Estimated Annual Costs
[2020 Dollars]
----------------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------------
Potential Costs:
Material Costs per Vehicle.............. $325 to $591.
Material Costs, Total New Fleet......... $0.71 million to $1.30 million.
Fuel Costs per Vehicle @ 3%................. $2,441 to $4,790.
Fuel Costs per Vehicle @ 7%................. $1,862 to $3,654.
Fuel Costs, Total New Fleet................. $4.10 million to $10.54 million.
-------------------------------------------------------------------
Total Annual Cost....................... $4.81 million to $11.84 million.
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Table 2--Estimated Annual Benefits
[Undiscounted equivalent lives saved]
------------------------------------------------------------------------

------------------------------------------------------------------------
15 percent belt usage................................ 3.12
90 percent belt usage................................ 2.45
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Table 3--Cost per Equivalent Life Saved
[Across 3% and 7% discount, in millions of 2020 dollars]
------------------------------------------------------------------------

------------------------------------------------------------------------
15 percent belt usage................................ 2.48-4.99
90 percent belt usage................................ 3.17-6.38
------------------------------------------------------------------------

Table 4--Annualized Costs and Benefits
[In millions of 2020 dollars]
----------------------------------------------------------------------------------------------------------------
Annual costs Annual benefits Net Benefits
----------------------------------------------------------------------------------------------------------------
15% belt usage:
3% Discount Rate................................... 6.08-11.84 29.40 17.56-23.31
7% Discount Rate................................... 4.81-9.34 22.43 13.09-17.61
90% belt usage:
3% Discount Rate................................... 6.08-11.84 23.05 11.21-16.97
7% Discount Rate................................... 4.81-9.34 17.59 8.25-12.78
----------------------------------------------------------------------------------------------------------------

e. NHTSA's Determination of MAP-21 Requirements and Considerations

Section 32703(b) and (b)(1) of MAP-21 direct NHTSA: (a) To
establish improved roof and roof support standards for motorcoaches
that substantially improve the resistance of motorcoach roofs to
deformation and intrusion to prevent serious occupant injury in
rollover crashes involving motorcoaches; if (b) NHTSA determines that
such standards meet the requirements and considerations set forth in
subsections (a) and (b) of section 30111 of the Safety Act. In
addition, section 32703(b)(2) directs NHTSA to consider portal
improvements to prevent partial and

[[Page 74274]]

complete ejection of motorcoach passengers, including children, if such
standards meet the requirements and considerations set forth in
subsections (a) and (b) of section 30111 of the Safety Act.
NHTSA has determined that the standard issued by this final rule
meets the requirements and considerations of section 30111(a) and (b)
of the Safety Act.
Section 30111(a)
The provision at 49 U.S.C. 30111(a) of the Safety Act authorizes
the Secretary (NHTSA, by delegation) to prescribe Federal motor vehicle
safety standards that are practicable, meet the need for motor vehicle
safety, and are stated in objective terms. ``Motor vehicle safety'' is
defined in the Safety Act as ``the performance of a motor vehicle or
motor vehicle equipment in a way that protects the public against
unreasonable risk of accidents occurring because of the design,
construction, or performance of a motor vehicle, and against
unreasonable risk of death or injury in an accident, and includes
nonoperational safety of a motor vehicle.'' \14\
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\14\ 49 U.S.C. 30102(a)(8).
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NHTSA has determined that the standard issued by this final rule
meets the requirements and considerations of section 30111(a) of the
Safety Act. The standard is practicable, since it is based on the 2006
ECE R. 66 complete vehicle rollover test. New buses sold in Europe and
other countries have been designed to meet the ECE R.66 rollover test
requirements for over a decade. Further, NHTSA has conducted the
vehicle rollover test of ECE R.66 in developing the NPRM. The three bus
rollover tests the agency conducted using the ECE R.66 complete vehicle
rollover test procedure showed that the test is feasible and practical
for evaluating how well a bus structure maintains occupant survival
space in a rollover. The standard is also cost beneficial, and thus is
economically practicable.
Standard No. 227 meets the need for safety. Two of the real-world
rollover crashes examined for this rule involved buses that had
complete roof separation during the rollovers.\15\ Almost all the
passengers in those two crashes were ejected due to the loss of the bus
roofs. This standard will increase the likelihood that bus structures
maintain their roof structure and provide a residual survival space for
the vehicle occupants. Studies of bus structures before and after
implementation of ECE R.66 have concluded those requirements are
effective in protecting bus occupants in rollover crashes.\16\ A bus
design in use prior to ECE R.66 experienced complete structural
collapse of the roof in a rollover crash with one and a half full 360
degree rolls down a 6-meter embankment. That bus model redesigned to
meet ECE R.66 requirements was able to maintain adequate survival space
in a rollover crash with two and a quarter full 360 degree rolls down a
9-10 meter embankment.\17\
---------------------------------------------------------------------------

\15\ These rollover crashes occurred in Turrell, Arkansas in
2004 and Mexican Hat, Utah in 2008.
\16\ Matolcsy, M. (2007), ``The Severity of Bus Rollover
Accidents,'' Enhanced Safety of Vehicles (ESV) Paper 07-152, 20th
ESV Conference, Lyon, France. Available at: <a href="https://www-esv.nhtsa.dot.gov/Proceedings/20/07-0152-O.pdf">https://www-esv.nhtsa.dot.gov/Proceedings/20/07-0152-O.pdf</a>, last accessed April
26, 2021.
\17\ Matolcsy, M. (2006), ``Rollover accident with ejection of
occupants.'' Informal working document of GRSG, No. GRSG-91-7. GRSG,
91st session, Geneva, October 2006.
---------------------------------------------------------------------------

This final rule meets the need for safety on many fronts. NHTSA's
Motorcoach Safety Action Plan targeted safety improvements for buses to
reduce the incidence of fatalities and serious injuries caused by bus
rollover accidents. The seat belt requirements in FMVSS No. 208 \18\
for large buses provided a means for belted bus occupants to remain
within the survival space in a crash. Buses designed to FMVSS No. 227
will provide a survival space for bus occupants. Anti-ejection
requirements adopted for bus window portals \19\ will reduce the
incidence of partial ejection of belted occupants as well as reduce the
occurrence of partial or full ejection of unbelted occupants. Further,
NHTSA has proposed to establish an FMVSS to require advanced glazing
that is highly resistant to occupant ejection for each motorcoach
portal, pursuant to section 32703(b)(2) of MAP-21.\20\ This final rule
adopting FMVSS No. 227 would complement FMVSS No. 217a by improving the
securement of the advanced glazing in the buses.
---------------------------------------------------------------------------

\18\ 78 FR 70416, November 25, 2013.
\19\ 81 FR 27904, May 6, 2016.
\20\ May 6, 2016 (81 FR 27904), supra.
---------------------------------------------------------------------------

The available information shows this final rule is cost beneficial.
NHTSA estimates that requiring the subject buses to meet the
performance criteria in this final rule will save approximately 2-3
lives and prevent 4 serious injuries annually. NHTSA estimates the net
benefits range from $8.3 million to $23.3 million.
Standard No. 227 is stated in objective terms. The residual
survival space is well defined, based upon a specified boundary at each
transverse cross-section of the vehicle, with the cross-sections
bounded by specified forwardmost and rearmost vehicle landmarks.
Potential intrusion into the residual survival space may be objectively
measured using standard test measurement methodologies-such as
templates representing the outline of the residual survival space and
high-speed video. The FMVSS No. 227 test procedure matches the full
vehicle test procedure of ECE R.66. Studies have shown the ECE R.66
full vehicle rollover test to be a relatively severe loading condition
replicating real-world bus rollover crashes.\21\
---------------------------------------------------------------------------

\21\ Matolcsy, M. (2007), ``The Severity of Bus Rollover
Accidents,'' Enhanced Safety of Vehicles (ESV) Paper 07-152, 20th
ESV Conference, Lyon, France. Available at: <a href="https://www-esv.nhtsa.dot.gov/Proceedings/20/07-0152-O.pdf">https://www-esv.nhtsa.dot.gov/Proceedings/20/07-0152-O.pdf</a>, last accessed April,
26 2021.
---------------------------------------------------------------------------

Section 30111(b)
The provision at 49 U.S.C. 30111(b) specifies that, when
prescribing such standards, the Secretary must consider all relevant,
available motor vehicle safety information, consult with the states as
appropriate, consider whether a standard is reasonable, practicable,
and appropriate for the types of motor vehicles or motor vehicle
equipment for which it is prescribed, and consider the extent to which
the standard will carry out the statutory purpose of section 30101 of
the Act. Section 30101 states that the purpose of the statute is to
reduce traffic accidents and deaths and injuries resulting from traffic
accidents, and that it is therefore necessary to prescribe FMVSS, and
to carry out needed safety research and development.
NHTSA has issued this final rule in accordance with section
30111(b). As discussed throughout this document, the agency concludes,
after comprehensive reviews of relevant available safety information
that includes over 15 years of crash data and development of a NHTSA
plan for motorcoach safety,\22\ that adopting FMVSS No. 227 meets the
requirements and considerations of the Safety Act. NHTSA has provided
the public with opportunities to review and provide input on the
agency's safety plan and comment on adoption of this structural
integrity final rule when it was in proposed form. This final rule
accords with National Transportation Safety Board Recommendations H-99-
50, H-99-51, H-09-23, and H-09-24, and NHTSA expects wide public
support overall for this final rule. NHTSA has determined that FMVSS
No. 227 is reasonable and appropriate for the

[[Page 74275]]

vehicles to which the standard applies for improving bus occupant
protection in rollover crashes and that establishing FMVSS No. 227
meets the purpose and policy of the Safety Act.
---------------------------------------------------------------------------

\22\ NHTSA's Approach to Motorcoach Safety (2007), (Docket No.
NHTSA-2007-28793-001), supra.
---------------------------------------------------------------------------

f. Retrofitting

NHTSA has decided not to require existing large buses to meet the
requirements adopted today for new buses. None of the commenters
supported a retrofitting requirement. Based on its tests of older
buses, the agency believes that many existing buses may need major
structural changes to the vehicle's sidewall and roof structure to meet
the requirements adopted in this document. Such structural changes are
likely to be cost-prohibitive, making retrofitting impracticable.

II. Introduction

Over the 15-year period between 2004 and 2018, data from NHTSA's
Fatality Analysis Reporting System (FARS) indicate there were 122 fatal
crashes involving large buses. These crashes resulted in 326 occupant
fatalities (274 passenger and 52 driver fatalities). During this
period, on average 22 fatalities occurred annually to occupants of
these buses.
Data indicate that rollover crashes are a particular safety problem
for these buses. Among the 122 fatal crashes, 56 were rollover crashes
resulting in 189 fatalities. While fatal rollover crashes constitute
about 43 percent of all fatal crashes involving these bus types, they
represent about 58 percent of all the occupant fatalities. Further, 56
percent of the rollover crash fatalities were attributable to occupant
ejections (106 ejection fatalities out of the total of 189 fatalities
in bus rollover crashes).
Congress was especially concerned about motorcoach rollover crashes
in passing provisions of MAP-21 relevant to this final rule. MAP-21
requires DOT to ``establish improved roof and roof support standards
for motorcoaches that substantially improve the resistance of
motorcoach roofs to deformation and intrusion to prevent serious
occupant injury in rollover crashes involving motorcoaches'' if such
standards meet the requirements and considerations set forth in
subsections (a) and (b) of section 30111 of title 49, United States
Code.\23\ Under MAP-21, ``motorcoach'' means an OTRB, but does not
include a bus used in public transportation provided by, or on behalf
of, a public transportation agency, or a school bus. MAP-21 \24\ also
directs DOT to consider ``portal improvements to prevent partial and
complete ejection of motorcoach passengers, including children.''
---------------------------------------------------------------------------

\23\ MAP-21, section 32703(b)-(b)(1).
\24\ Id., section 32703(b)(2).
---------------------------------------------------------------------------

In accordance with MAP-21 and the Safety Act, we have issued this
rollover-specific rule to apply to buses associated with an
unreasonable risk of fatal rollover involvement. Thus, this final rule
applies to OTRBs, and to all non-OTRBs with a GVWR greater than 11,793
kg (26,000 lb) (large buses), with some exceptions. The final rule
excludes school buses, prison buses, non-OTRB transit buses, and buses
with perimeter seating.\25\ We have applied this rule to meet the
requirements and considerations of MAP-21 and the Safety Act.
---------------------------------------------------------------------------

\25\ Under the standard, a bus with perimeter seating is 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.
---------------------------------------------------------------------------

NHTSA is enhancing the safety of large buses in rollovers both by
providing a survival space in the occupant compartment, and by reducing
the likelihood of emergency exits opening during bus rollovers and
becoming ejection portals. NHTSA achieved an important first step
enhancing the safety of the buses in rollovers by the November 25, 2013
final rule that requires lap/shoulder belts for all passengers in large
capacity buses.\26\ This final rule builds on the rollover protection
provided by seat belts by ensuring the buses provide a protective
survival space for belted and unbelted retained occupants in rollovers.
The 2013 seat belt rule significantly increased the ability of
occupants of large buses to be retained in the bus structure in
rollover crashes. This final rule provides the retained occupants a
survival space in the bus structure, and strengthens the bus structure
and emergency exit portals to protect unbelted occupants as well.
---------------------------------------------------------------------------

\26\ NHTSA estimates that seat belts are 77 percent effective in
preventing fatalities in rollover crashes.
---------------------------------------------------------------------------

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.\27\ 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 two 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.\28\
---------------------------------------------------------------------------

\27\ Moving Ahead for Progress in the 21st Century Act, Public
Law 112-141 (Jul. 6, 2012).
\28\ Id. at section 32703(b).
---------------------------------------------------------------------------

There are two subsections of section 32703(b) that 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

[[Page 74276]]

improvements to prevent partial and complete ejection of motorcoach
passengers, including children.'' \29\
---------------------------------------------------------------------------

\29\ 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).\30\ 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.\31\
---------------------------------------------------------------------------

\30\ Moving Ahead for Progress in the 21st Century Act, Public
Law 112-141, section 32702(6).
\31\ Id. at section 32702(6)(A)-(B).
---------------------------------------------------------------------------

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.\32\ 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).\33\ Finally, MAP-21 also authorizes the Secretary to
combine the required rulemaking actions as the Secretary deems
appropriate.\34\
---------------------------------------------------------------------------

\32\ Id. at section 32703(e)(1).
\33\ Id. at section 32703(e)(2). ``Retrofit Assessment for
Existing Motorcoaches.''
\34\ Id. at section 32706.
---------------------------------------------------------------------------

IV. Safety Need (FARS 2004-2018 Data Analysis)

This rulemaking is conducted pursuant to the requirements of the
Safety Act and MAP-21. It investigates whether there are unreasonable
safety risks associated with rollover crashes in OTRB transportation,
and if there are such risks, whether those safety risks can be
reasonably reduced by having at least minimum levels of performance
specified for rollover structural integrity and portal improvements.
This rulemaking improves occupant safety in large bus rollover
crashes. While developing the November 25, 2013 seat belt final rule,
NHTSA found that most fatalities in OTRB crashes are attributable to
rollovers. Because more than half of the rollover fatalities are
attributable to ejections, NHTSA issued a seat belt requirement to
mitigate those ejections.
Enhancing the structural integrity of the interior of these buses
works together with the seat belt rule. More occupants will be able to
be retained in the bus compartment because of the belts, so it makes
sense to require a survival space that protects these restrained
occupants in a rollover. Moreover, regardless of whether occupants are
belted, data \35\ show that the risk of serious injuries and fatalities
can be reduced by improving the vehicle structure to protect occupants
against collapsing roofs and bus components falling or intruding into
the survival space. Additionally, emergency exits should remain closed
in a crash, as an open exit forms a portal through which occupants
could be completely or partially ejected. This final rule adopts
requirements to meet these objectives.\36\
---------------------------------------------------------------------------

\35\ Ma[eacute]tolcsy, M (2012), ``Passenger's Ejection in Bus
Rollover Accident,'' FISITA 2012 World Automotive Congress, paper
F2012 F02-005. Available at <a href="https://unece.org/DAM/trans/doc/2012/wp29grsg/GRSG-103-02e.pdf">https://unece.org/DAM/trans/doc/2012/wp29grsg/GRSG-103-02e.pdf</a>. Last accessed May 03, 2021.
\36\ This final rule does not address the issue of glazing
breaking in a rollover crash that would result in openings through
which occupants could be completely or partially ejected even if
emergency exits remain closed. This matter is addressed in the 2016
NPRM for advanced glazing (81 FR 27904), supra.
---------------------------------------------------------------------------

Updated Data Analysis (FARS Data 2004-2018)
After the August 6, 2014 NPRM, NHTSA re-analyzed FARS data files
for the years 2004 to 2018 to assess the impacts of this
rulemaking.\37\ The bus body types coded in FARS are ``school bus,''
``transit bus,'' ``cross country/intercity bus'' to represent OTRBs
(motorcoaches), ``other bus'' to represent other types of buses, and
``unknown bus'' to represent buses that could not be categorized into
the other four bus body type categories. Since 2011, a new bus body
type, ``van-based buses'' was included. We also examined the FARS body
type ``Large Van'' for van-based bus crashes for the years 2004-2018
where the vehicle was used to transport people. The buses can also be
categorized by their GVWR: GVWR less than or equal to 10,000 lb, GVWR
greater than 10,000 lb and less than or equal to 26,000 lb, and GVWR
greater than 26,000 lb. The manner in which a bus was used is coded in
FARS as ``school bus,'' ``intercity bus,'' ``transit/city bus,''
``shuttle bus,'' and ``modified for personal/private use.''
---------------------------------------------------------------------------

\37\ Later in this preamble we discuss our analysis of updated
data regarding buses with a GVWR of 10,000-26,000 lb.
---------------------------------------------------------------------------

To assess the benefits and costs of this rule, the agency selected
buses of body type ``over-the-road bus (OTRB)'' regardless of GVWR \38\
and ``other bus,'' ``unknown bus'' and ``van-based bus'' body types
with a GVWR greater than 26,000 lb, regardless of the manner in which
they were used.\39\ NHTSA also included fatal crashes of large vans
with a GVWR greater than 26,000 lb used for transporting people (used
as intercity bus, charter/tour bus, commuter bus, and shuttle bus) and
found none for the 15-year period from 2004 to 2018.
---------------------------------------------------------------------------

\38\ All OTRBs (cross country/intercity buses) are covered under
MAP-21.
\39\ Crashes and fatalities of unknown GVWR buses were
proportionally distributed amongst the known values.
---------------------------------------------------------------------------

For the 15-year period from 2004 to 2018, there were a total of 326
bus occupant fatalities in the bus types covered by of FMVSS No. 227
(see Table 5). Among these fatalities, 230 were occupants of OTRBs with
a GVWR greater than 26,000 lb, 15 were occupants of OTRBs with GVWR
<26,000 lb, and 81 were occupants in buses coded as ``other bus,''
``unknown bus,'' and ``van-based bus'' with a GVWR greater than 26,000
lb. In this 15-year period, fatalities among occupants of OTRBs account
for 75 percent of the 326 fatalities.

Table 5--Bus Crash Occupant Fatalities in the Bus Types Covered by FMVSS No. 227
[FARS data 2004-2018]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Unknown bus
Year OTRB GVWR OTRB GVWR Other bus GVWR GVWR >26,000 Van-based GVWR Total
<26,000 lb >26,000 lb >26,000 lb lb >26,000 lb
--------------------------------------------------------------------------------------------------------------------------------------------------------
2004.................................................... 0 23 4 0 .............. 27
2005.................................................... 0 10 3 4 .............. 17

[[Page 74277]]

2006.................................................... 0 8 2 3 .............. 13
2007.................................................... 1 18 8 0 .............. 27
2008.................................................... 0 38 2 0 .............. 40
2009.................................................... 0 9 1 0 .............. 10
2010.................................................... 0 11 1 0 .............. 12
2011.................................................... 0 30 0 0 .............. 30
2012.................................................... 2 12 1 0 1 16
2013.................................................... 9 8 3 1 0 21
2014.................................................... 1 18 5 1 0 25
2015.................................................... 0 12 3 6 0 21
2016.................................................... 1 8 26 0 0 35
2017.................................................... 1 5 1 0 0 7
2018.................................................... 0 13 5 0 0 18
-----------------------------------------------------------------------------------------------
Total............................................... 15 230 65 15 1 326
--------------------------------------------------------------------------------------------------------------------------------------------------------

The bus occupant fatalities were further classified by the type of
crash (rollover, front, side, rear). FARS also coded fatal bus events
``other'' that could not be classified into one of the four crash
types. The bus occupant fatalities in these ``other'' bus crash types
were further analyzed and found to result from occupants jumping or
falling off the bus, bus fire, explosion inside the bus, heavy object
falling on an occupant, and fatal injuries to an occupant that are not
crash related. Because these fatalities were not crash related, we did
not include them in the count of bus crash fatalities.
In the 15-year period from 2004 to 2018, there were 122 fatal bus
crashes of bus types covered by FMVSS No. 227, among which 71 involved
OTRBs with a GVWR greater than 26,000 lb (Table 6). Among the 122
crashes, 56 were rollover events, 59 were frontal crashes, 7 were side
crashes, and 0 were rear crashes.

Table 6--Fatal Crashes of Bus Types Covered by FMVSS No. 227
[FARS 2004-2018]
----------------------------------------------------------------------------------------------------------------
Bus body type and GVWR Rollover Frontal Side Rear Total
----------------------------------------------------------------------------------------------------------------
OTRB (GVWR <=26,000 lb)......... 7 2 0 0 9
OTRB (GVWR >26,000 lb).......... 35 33 3 0 71
Other (GVWR >26,000 lb)......... 11 18 3 0 32
Unknown (GVWR >26,000 lb)....... 3 5 1 0 9
Van-based (GVWR >26,000 lb)..... 0 1 0 0 1
-------------------------------------------------------------------------------
Total....................... 56 59 7 0 122
----------------------------------------------------------------------------------------------------------------

The 122 fatal bus crashes (involving bus types covered under FMVSS
No. 227) resulted in 326 bus occupant fatalities (52 drivers and 274
passengers), as shown in Table 7. Among these fatalities, 189 persons
(11 drivers, 178 passengers) died in 56 rollover crashes. In contrast,
116 persons (40 drivers, 76 passengers) died in 59 frontal crashes. Bus
rollover crashes accounted for 58 percent of the total bus occupant
fatalities and 65 percent of the passenger fatalities.
These data show the devastating nature of bus rollover events,
where a significant number of fatal or serious injuries can occur in a
single bus rollover event. Among the 189 fatalities in bus rollover
events, 149 fatalities (79 percent) were in OTRBs with a GVWR greater
than 26,000 lb.

Table 7--Bus Occupant Fatalities in Crashes of Bus Types Covered by FMVSS No. 227 by Bus Body Type, GVWR, Crash Type, and Occupant Type
[FARS data 2004-2018]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rollover Front Side Rear All types Total
---------------------------------------------------------------------------------------------------- Driv
Bus body type and GVWR <plus-
Driv Pass Driv Pass Driv Pass Driv Pass Driv Pass minus>
Pass
--------------------------------------------------------------------------------------------------------------------------------------------------------
OTRB (GVWR <=26,000 lb)................... 2 11 1 1 0 0 0 0 3 12 15
OTRB (GVWR >26,000 lb).................... 7 142 25 46 1 9 0 0 33 197 230
Other (GVWR >26,000 lb)................... 1 23 12 23 0 6 0 0 13 52 65
Unknown (GVWR >26,000 lb)................. 1 2 2 5 0 5 0 0 3 12 15
Van-based (GVWR >26,000 lb)............... 0 0 0 1 0 0 0 0 0 1 1
-------------------------------------------------------------------------------------------------------------
Total................................. 11 178 40 76 1 20 0 0 52 274 326
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 74278]]

NHTSA also examined bus rollover events by the ejection status of
occupants, among bus types covered by FMVSS No. 227 (see Table 8).
Among the 178 passenger fatalities in bus rollover events, 98 were to
occupants ejected or partially ejected from the bus.

Table 8--Bus Occupant Fatalities in Rollovers in Bus Types Covered by FMVSS No. 227 by Bus Body Type, GVWR,
Occupant Type, and Ejection Status
[FARS 2004-2013]
----------------------------------------------------------------------------------------------------------------
Driver Passenger
Bus body type and GVWR ---------------------------------------------------------------
Not ejected Ejected Not ejected Ejected
----------------------------------------------------------------------------------------------------------------
OTRB (GVWR <=26,000 lb)......................... 0 2 4 7
OTRB (GVWR >26,000 lb).......................... 3 4 60 82
Other bus (GVWR >26,000 lb)..................... 0 1 16 7
Unknown bus (GVWR >26,000 lb)................... 0 1 0 2
Van-based bus (GVWR >26,000 lb)................. 0 0 0 0
---------------------------------------------------------------
Total....................................... 3 8 80 98
----------------------------------------------------------------------------------------------------------------

These data show that while transportation by OTRBs (and other
similar large buses) is an overall safe form of transportation, given
the high occupancy of these vehicles, a significant number of fatal or
serious injuries can occur in a single crash. This is especially true
in bus rollover crashes that result in occupant ejections.

V. Summary of the NPRM

The NPRM underlying this final rule published August 6, 2014 (79 FR
46090). The agency proposed adoption of a new FMVSS No. 227 to set
performance requirements that large buses must meet when tested using
the full vehicle ECE R.66 test.
In support of the NPRM, the agency researched two existing roof
crush/rollover standards: FMVSS No. 220, ``School bus rollover
protection,'' and ECE R.66, ``Uniform Technical Prescriptions
Concerning the Approval of Large Passenger Vehicles with Regard to the
Strength of their Superstructure.'' \40\ The agency purchased three
different bus models for this test program. Two older models were
selected because they were representative of the range of roof
characteristics (such as design, material, pillars, shape, etc.) of
large bus roofs in the U.S. fleet. The vehicles selected were two 12.2
meters (m) (40 feet) long model year (MY) 1992 MCI model MC-12, and two
12.2 m (40 feet) long MY 1991 Prevost model (Prevost) LeMirage buses.
The agency also procured a MY 2000 MCI bus, Model 102-EL3, that was
13.7 m (45 foot) in length. All five of the buses purchased were tested
to requirements in either FMVSS No. 220 or ECE R.66. A summary of the
testing program can be found in the NPRM, supra, in section IV.b (79 FR
46100-46102).\41\
---------------------------------------------------------------------------

\40\ ECE R.66 defines ``superstructure'' as ``the load-bearing
components of the bodywork as defined by the manufacturer,
containing those coherent parts and elements which contribute to the
strength and energy absorbing capability of the bodywork, and
preserve the residual space in the rollover test.'' ``Bodywork''
means ``the complete structure of the vehicle in running order,
including all the structural elements which form the passenger
compartment, driver's compartment, baggage compartment and spaces
for the mechanical units and components.'' (Footnote added.)
\41\ For further information on the four older buses tested, a
detailed discussion of the tests and results are available in the
docket entry NHTSA-2007-28793-0019. For further information on the
newer vehicle tested, see the test report, ``ECE Regulation 66 Based
Research Test of Motorcoach Roof Strength, 2000 MCI 102-EL3 Series
Motorcoach, NHTSA No.: MY0800,'' October 1, 2009, Report No.: ECE
66-MGA-2009-001, which can be found on NHTSA's website. <a href="https://www-nrd.nhtsa.dot.gov/database/aspx/searchmedia2.aspx?database=v_=6797&mediatype=r&r&lowbar">https://www-nrd.nhtsa.dot.gov/database/aspx/searchmedia2.aspx?database=v_=6797&mediatype=r&r&lowbar</a>;tstno=6797,
Report 8. Step-by-step instructions on accessing the research report
can be found in a memorandum in Docket No. NHTSA-2007-28793-0025.
---------------------------------------------------------------------------

Applicability
NHTSA proposed FMVSS No. 227 to apply 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), including prison buses and double-
decker buses.\42\ NHTSA focused on improving the rollover protection of
buses with a GVWR greater than 26,000 lb because these were high-
occupancy vehicles with an exceptionally high involvement in fatal
rollovers. The agency also focused on the buses to which the agency's
November 25, 2013 final rule on passenger seat belts applied.
---------------------------------------------------------------------------

\42\ Excepted from the NPRM were all school buses, and non-OTRB
transit buses and non-OTRBs with perimeter seating.
---------------------------------------------------------------------------

Performance Requirements
The NPRM proposed performance requirements that the buses must meet
when subjected to a dynamic rollover test. The proposed test procedure
replicated a rollover crash in a controlled manner. In the proposed
test, the bus is placed on a tilting platform that is 800 mm (31.50
inches) above a smooth and level concrete surface. One side of the
tilting platform along the length of the vehicle is raised at a steady
rate of not more than 5 degrees/second until the vehicle becomes
unstable, rolls off the platform, and impacts the concrete surface
below with its roof leading edge. The rollover structural integrity
test is illustrated below in Figure 1.
BILLING CODE 4910-59-P

[[Page 74279]]

[GRAPHIC] [TIFF OMITTED] TR29DE21.001

BILLING CODE 4910-59-C
NHTSA proposed that the agency could position the bus such that
either side (right or left) of the vehicle may be tested for
compliance, at the agency's option. The NPRM proposed that a mass of up
to 68 kg (150 lb) (ballast) be secured in each designated seating
position (DSP) equipped with a seat belt.
The main proposed performance requirements were as follows:
(1) Intrusion into the survival space by any part of the vehicle
outside the survival space would be prohibited;
(2) Each anchorage of all seats and interior overhead luggage racks
and compartments would be prohibited from completely separating from
its mounting structure during movement of the tilting platform or from
impact of the bus on the impact surface; \43\
---------------------------------------------------------------------------

\43\ One reason for the proposal for overhead luggage racks was
to further enhance structural integrity. NHTSA thought that, to meet
the luggage rack retention requirement, a bus would have to limit
its deformation and ``racking'' in the test. ``Racking'' means the
tilting of the sides of the bus relative to the bus floor. The
retention requirement would have applied to luggage racks regardless
of their position relative to the survival space. If the rack
separated from its mounting it would be a failure, even if the
overhead luggage rack did not enter the survival space.
---------------------------------------------------------------------------

(3) Emergency exits would be required to remain shut during the
test, and, after the test, be operable in the manner required under
FMVSS No. 217, ``Bus emergency exits and window retention and
release''; and,
(4) Each side window glazing on the non-impacted side and roof of
the vehicle would be required to remain attached to its mounting such
that there is no opening that allows the passage of a 102 mm (4 inch)
diameter sphere when a force of no more than 22 Newtons (N) is applied
to the sphere at any vector in a direction from the interior to the
exterior of the vehicle.
The proposed requirements described in paragraphs (2), (3) and (4)
are beyond those specified in ECE R.66. The ECE regulation mainly
assesses the strength of the ``superstructure'' \44\ in preventing
intrusion into the survival space (ECE R.66 uses the term ``residual
space'' rather than survival space). The regulation specifies that the
superstructure of the vehicle shall have sufficient strength such that
no part of the vehicle that is outside the residual space at the start
of the test (e.g., pillars, luggage racks) shall intrude into the
residual space during the test.
---------------------------------------------------------------------------

\44\ ECE R.66 Revision 1 defines ``superstructure'' as ``the
load-bearing components of the bodywork as defined by the
manufacturer, containing those coherent parts and elements which
contribute to the strength and energy absorbing capability of the
bodywork, and preserve the residual space in the rollover test.''
---------------------------------------------------------------------------

VI. High Level Summary of the Comments

NHTSA received 19 comments on the NPRM from commenters that
included large bus manufacturers producing large buses domestically and
abroad (Van Hool, TEMSA, Prevost, MCI, Daimler EvoBus, Daimler Trucks/
Thomas Built Buses, IC Bus), small (final-stage) manufacturers
(Hemphill Brothers (Hemphill), NiteTrain Coach (NiteTrain)), a bus
industry group (American Bus Association (ABA)), a

[[Page 74280]]

glazing industry group (Enhanced Protective Glass Automotive
Association (EPGAA)), motorcoach operators (Greyhound, Hemphill,
NiteTrain \45\), the National Transportation Safety Board (NTSB), a
research laboratory (Florida A&M University's and Florida State
University's Crashworthiness and Impact Analysis Laboratory (CIAL)), a
consumer advocacy group (Advocates for Highway Safety (Advocates)), a
group of families of passengers involved in six bus crashes, and two
private citizens.
---------------------------------------------------------------------------

\45\ Both Hemphill and NiteTrain describe themselves not only as
manufacturers of ``entertainer buses'' but also providers of
motorcoach transportation services to the entertainment industry,
operating the vehicles under contractual arrangements. Hemphill
states that the majority of the contractual arrangements for
operating the motorcoaches exceed 30 days, with many contracts
covering periods of more than one year. Both Hemphill and NiteTrain
describe ``entertainer buses'' as customized vehicles that include
kitchens, bathrooms, bedrooms and lounging areas. Passengers are
members of entertainment groups, including the lead artists, band
members, road managers, stage hands and others, traveling on the
road to different performance venues.
---------------------------------------------------------------------------

There was almost unanimous support for an FMVSS on large bus
structural integrity, but differing views on what that standard should
require. European bus manufacturers Van Hool and TEMSA opposed the
proposed requirements and test procedures that differed from ECE R.66,
believing that the ECE R.66 test was appropriate for assessing the
strength of the bus superstructure and that subsystems such as seats,
overhead racks, emergency exits, and glazing should not be assessed
under the proposed standard. ABA concurred with this view. Daimler
Trucks/Thomas Built Buses and IC Bus generally supported the intent and
requirements of the NPRM but supported incorporating the test procedure
of FMVSS No. 220, ``School bus rollover protection'' (49 CFR 571.220),
rather than the test of ECE R.66, for school bus derived buses.
Hemphill and NiteTrain expressed concern about the test burdens on
small manufacturers and suggested, as did ABA and Prevost, excluding
entertainer buses from the standard. MCI and Van Hool suggested
excluding prison transport buses and double-decker buses, respectively.
Consumers and consumer groups believed the proposal was not
stringent enough or sufficiently representative of a high speed
motorcoach rollover crash involving a bus sliding down an embankment.
There were concerns expressed about the sphere test not representing
the force imposed by an unbelted passenger thrown against the bus
window. EPGAA believed that the proposed requirements should have
accounted more for the potential use of advanced glazing as an
ejection-mitigation countermeasure.
NTSB and CIAL believed the proposed standard should apply to all
non-OTRBs with a GVWR greater than 4,536 kg (10,000 lb), rather than
just to non-OTRBs with a GVWR greater than 11,793 kg (26,000 lb). NTSB
also suggested the proposed performance requirements should apply to
``moon roofs'' and to side emergency doors.
No commenter supported a retrofit requirement.

VII. Scope and Purpose of the Rule

NHTSA proposed in the NPRM that the scope of FMVSS No. 227 would be
to establish performance requirements for bus rollover structural
integrity, and that the purpose of the standard would be to reduce
death and injuries resulting from the structural collapse of the bus
body structure, the unintended opening of emergency exits, and the
detachment of window glazing, seats, and overhead luggage racks.
Van Hool, TEMSA, and the ABA opposed the scope of the proposed
requirements and test procedures. The commenters believed that the ECE
R.66 test was appropriate for assessing the strength of the bus
``superstructure'' but that subsystems such as seats, overhead racks,
emergency exits, and glazing should not be assessed under FMVSS No.
227. Those commenters, and Prevost, believed that the ECE R.66 rollover
test is only designed for, and is capable only of, providing an
evaluation of the bus superstructure strength.
ECE R.66 defines ``superstructure'' as ``the load-bearing
components of the bodywork as defined by the manufacturer, containing
those coherent parts and elements which contribute to the strength and
energy absorbing capability of the bodywork, and preserve the residual
space in the rollover test.'' ECE R.66 requires that the superstructure
of the bus must have sufficient strength to ensure that, during and
after the rollover test, no part of the vehicle that is outside the
survival space at the start of the test intrudes into the survival
space during the test.
Agency Response
This final rule adopts the NPRM's proposed prohibition that no part
of the bus that is outside the survival space shall intrude into the
survival space, both during movement of the tilting platform or
resulting from impact of the bus on the impact surface.\46\ However,
after consideration of the comments, NHTSA has decided not to adopt the
NPRM's proposal that each anchorage of an interior overhead luggage
rack or other compartment must not completely separate from its
mounting structure during movement of the tilting platform or resulting
from impact of the bus on the impact surface or that seat anchorages
not become dislodged during the test.
---------------------------------------------------------------------------

\46\ In response to comments, however, the final rule permits
detritus and other debris caused by the impact to fall into the
survival space, such as small glazing pebbles or bolts and screws.
The objects must not weigh more than 15.0 grams. This issue is
discussed in detail below.
---------------------------------------------------------------------------

Under the NPRM, those proposed prohibitions would have applied even
if the luggage rack does not enter the survival space, or the seat
anchorages dislodge within the survival space. NHTSA has decided that
the primary purpose of this rulemaking is to establish a roof strength
and crush resistance standard that improves the resistance of the bus
superstructure to deformation and intrusion, i.e. , by providing a
survival space to occupants in rollovers. The purpose is achieved by
prohibiting any structure, such as overhead luggage racks, from
intruding into the survival space. By prohibiting overhead luggage
racks from impeding into the survival space in the rollover, overhead
luggage racks will have to be better anchored to the bus wall than they
had been in the past, so that they do not detach and intrude into the
survival space in the test. Thus, the proposed luggage rack provision
is not needed to provide a survival space, since luggage racks are
prohibited from intruding into the survival space. By being securely
anchored so that they do not fall into the survival space, luggage
racks will be less likely to impede egress in an emergency, or fall and
cause head and neck injuries to occupants.
NHTSA has decided against adopting the NPRM's proposal that seat
anchorages must not become dislodged during the test. The agency
believes the seat anchorage provision is not necessary to achieve a
survival space for occupants. NHTSA proposed the requirement for the
retention of seat anchorages because of the agency's test of the MY
1991 Prevost LeMirage bus.\47\ In the test, anchorages of a seat with a
restrained mid-size adult male dummy completely separated from its bus
attachment location, allowing the seat to fall across the bus with the
restrained dummy attached to the seat. NHTSA believed at the NPRM stage
that the

[[Page 74281]]

failure of the seat anchorages during the rollover test presented a
significant safety risk to restrained occupants in bus rollover events
and reduced the effectiveness of seat belts.
---------------------------------------------------------------------------

\47\ A summary of the test may be found in the NPRM, supra, in
section IV.b 79 FR 46100-46102.
---------------------------------------------------------------------------

However, after considering the comments and other information,
NHTSA concludes a specific requirement in FMVSS No. 227 for seat
anchorages to remain completely attached is unnecessary for several
reasons. First, the seat anchorages in the MY 1991 Prevost LeMirage
separated from the bus because the seat was bolted to unreinforced
sheet metal of the bus sidewall. In NHTSA's test of the newer MY 2000
MCI bus Model 102-EL3, none of the seats anchorages failed--despite the
fact that certain seats were ballasted with either a 150 lb
anthropomorphic ballast or with 150 lb steel weights. That is, the
seats remained attached even while tested under highly demanding
conditions, with the ballasts attached to the seats. This test of the
MY 2000 MCI bus demonstrates that bus seat anchorage designs have
improved since the MY 1991 and 1992 buses NHTSA tested in its test
program.
Second, it is likely the connectivity strength of seat anchorage
designs have improved even more since the design of the MY 2000 bus
because of the agency's 2013 final rule requiring lap/shoulder belts on
all large buses. The final rule requires the lap/shoulder belts to be
integral to the bus seats, and that the belt anchorage, together with
the seat anchorage to the bus, meet the rigorous strength requirements
of FMVSS No. 210, ``Seat belt assembly anchorages'' (49 CFR 571.210).
FMVSS No. 210 requires seat anchorages, attachment hardware, and
attachment bolts to withstand loads of 13,345 N (3,000 lb) applied
simultaneously to the lap belt portion and the shoulder belt portion of
the Type 2 restraint system. The seat anchorages of new large buses
meeting FMVSS No. 210 will be reinforced over and beyond the design of
a MY 2000 bus, which reduces the risk even further that the seats will
detach from the bus structure in a rollover as had been observed in the
tests of the MY 1991 and 1992 buses. Thus, adding a specific
requirement in FMVSS No. 227 for the seat anchorages to remain
completely attached duplicates the seat anchorage retention
requirements of FMVSS No. 210.
The agency's bus rollover tests found that glazing panels vacated
their window mountings during the rollover. In adopting the proposal
that items outside of the survival space must not enter the survival
space, this final rule prohibits large panes of glazing falling into
the survival space from the non-struck side of the bus and injuring
occupants. Strengthening the structure of the bus and glazing mountings
to resist the rollover crash forces that act to pop out window glazing
is an important ``portal improvement'' to prevent partial and complete
ejection of motorcoach passengers,'' as directed by MAP-21 section
32703(b)(2). Further, strengthening the frames is critical to rollover
safety if the subject buses employ advanced glazing that mitigate the
risk of occupant ejection in rollovers. NHTSA research into advanced
glazing as a means of mitigating occupant ejection \48\ revealed the
need for significant improvement in the structural integrity of
motorcoaches before the benefits of advanced glazing materials could be
achieved. FMVSS No. 227's survival space requirement will help prevent
glazing from popping out or otherwise detaching from its window mount
and will help ensure the safety countermeasures are retained in the
window frames in a crash.
---------------------------------------------------------------------------

\48\ Martec Limited, ``Motorcoach Glazing Retention Test
Development For Occupant Impact During a Rollover,'' August 2006;
Docket No. NHTSA-2002-11876-0015. Among other things, this research
found that advanced glazing, such as laminate glazing, could pop out
of its mounting due to torsional deformation of the structure around
the window.
---------------------------------------------------------------------------

This final rule adopts the requirement for emergency exits to
remain closed. This requirement is beyond ECE R.66 but is needed to
address concerns relevant to the U.S. NHTSA's bus rollover tests found
that emergency exit windows and roof hatches opened during the
rollover. NHTSA considers open emergency exits potential safety
hazards, as open emergency exits create unsafe ejection portals during
a rollover crash. Approximately two-thirds of the fatalities in bus
rollover crashes in this country involve occupants ejected from the
bus. Reducing the likelihood of ejections through these portals by
upgrading latches and hinges will reduce the fatality risk in rollovers
and conform to the mandate of MAP-21 section 32703(b)(2).
ABA states that NHTSA placed too much emphasis on preventing
unbelted passenger ejection rather than on ensuring the integrity of
the body structure. It also states that the FMVSS No. 227 requirements
that are not in ECE R.66 replicate the benefits already achieved
through the bus seat belt rule.
NHTSA does not agree that FMVSS No. 227 overemphasizes unbelted
passengers. Passengers using seat belts, and those that do not, will
benefit from the standard by being protected from collapsing bus
structures or contact with loose heavy objects. The requirements of
FMVSS No. 227 supplement, and do not replicate, the agency's final rule
on passenger seat belts. With belted passengers more likely to be
retained in the bus interior because of the belts, FMVSS No. 227
improves the protective attributes of the occupant compartment in which
they are retained. FMVSS No. 227 will benefit unbelted occupants by
helping retain glazing in window frames and providing at least a
minimum level of protection against dangerous structural collapse into
the occupant compartment. The requirement that emergency exits remain
closed during the rollover test increases the likelihood that emergency
exits do not become ejection portals during rollover crashes, including
crashes involving more than a quarter turn. These requirements will
benefit belted and unbelted occupants, as keeping side window exits
closed protects against partial ejection of belted occupants and
partial and complete ejections of unbelted occupants, including
children.

VIII. Applicability of the Rule

NHTSA proposed to apply FMVSS No. 227 to high-occupancy vehicles
with an unreasonably high involvement in fatal rollovers, and on which
Congress focused in MAP-21.\49\ NHTSA proposed to apply FMVSS No. 227
to buses to which the agency's November 25, 2013 final rule on
passenger seat belts applied.\50\ NHTSA's view in the NPRM was that
FMVSS No. 227 should apply to those buses with seat belts, so that a
survival space could be provided to the belted occupants.\51\
---------------------------------------------------------------------------

\49\ MAP-21 Subtitle G, the ``Motorcoach Enhanced Safety Act of
2012,'' defined ``motorcoach'' as having the meaning given the term
``over-the-road bus'' in section 3038(a)(3) of TEA-21 (49 U.S.C.
5310 note) but did not include a transit bus or a school bus. Under
MAP-21, an over-the-road bus is a bus characterized by an elevated
passenger deck located over a baggage compartment.
\50\ NHTSA's seat belt rule applied to all new over-the-road
buses regardless of GVWR, including transit buses, prison buses, and
perimeter-seating buses). The rule also applied to non-OTRBs that
have a GVWR greater than 11,793 kg (26,000 lb), except for non-OTRB
transit buses, prison buses, and perimeter-seating buses. The seat
belt rule did not apply to school buses.
\51\ The proposed rollover structural integrity requirements
applied to all new over-the-road buses regardless of GVWR (except
for school buses). The rule also applied to all new non-OTRBs with a
GVWR greater than 11,793 kg (26,000 lb), except for school buses,
transit buses, and perimeter-seating buses.
---------------------------------------------------------------------------

The agency received a number of comments relating to the proposed
applicability of FMVSS No. 227. Two commenters requested us to include
medium-size buses (buses with a GVWR between 4,536-11,793 kg (10,000-
26,000 lb), two suggested excluding

[[Page 74282]]

entertainer buses, one suggested excluding prison transport buses and
another suggested excluding double-decker buses.

a. Medium-Size Buses (Buses With a GVWR of 4,536 to 11,793 kg (10,000-
26,000 lb))

In the NPRM, NHTSA proposed not applying FMVSS No. 227 to medium-
size buses. NHTSA based the decision on an analysis of crash data for
medium-size buses. The agency examined 2000-2009 FARS data showing 42
occupant fatalities in buses with a GVWR between 4,536-11,793 kg
(10,000-26,000 lb), of which 24 fatalities were a result of 13 rollover
crashes. Over the ten-year period between 2000-2009, medium-size buses
were associated with an average of 1.3 rollover crashes per year and
2.4 fatalities per year. In contrast, there was an average of 3.2
rollover crashes annually among large buses (OTRBs and non-OTRBs with a
GVWR greater than 11,793 kg (26,000 lb)). These large bus rollover
crashes resulted in an average of 11.4 fatalities per year. Among all
fatalities occurring in rollover crashes in buses coded in FARS as
``cross-country,'' ``other,'' and ``unknown'' with a GVWR greater than
4,536 kg (10,000 lb), 83 percent were in buses with a GVWR greater than
11,793 kg (26,000 lb).
Two commenters (NTSB, CIAL) disagreed with the agency and commented
that NHTSA should include medium-sized buses in the applicability of
FMVSS No. 227.\52\
---------------------------------------------------------------------------

\52\ While CIAL focused on paratransit medium-size buses, it
requests applying FMVSS No. 227 to all medium-size buses. Further,
as its comment does show that paratransit buses have a different
safety concern compared other medium-size buses, we are responding
to the comment about the whole weight class rather than specifically
regarding paratransit buses only.
---------------------------------------------------------------------------

NTSB Comment
NTSB commented that medium-size buses are often used in a similar
fashion as motorcoaches with GVWRs over 11,793 kg (26,000 lb). It
disagreed with the data analysis in the NPRM showing that medium-size
buses do not have the same crash involvement as OTRBs and non-OTRBs
with a GVWR over 11,793 kg (26,000 lb). NTSB stated that FARS has
coding issues that may result in undercounting fatalities for the
medium-size bus type. It references several crashes that it believes
were not counted in the FARS database and suggest that the University
of Michigan's Buses Involved in Fatal Accidents (BIFA) database has a
more accurate classification of crashes.
Agency Response
NTSB correctly pointed out that we had not included the data that
NTSB discussed in its comment. We have updated our FARS data analysis
on medium-size buses to include these data. Even with the adjustment,
however, our analyses find that medium-size buses do not pose a
sufficient safety need to warrant application of FMVSS No. 227 to the
buses.
After NTSB commented, NHTSA carefully reexamined and updated FARS
data to determine whether the agency under-counted the medium-size bus
fatalities. We specifically used FARS data from 2004 to 2018 to
ascertain the fatalities attributable to medium-size buses.
FARS has five relevant categories for medium-size buses that are
non-OTRBs: ``other bus,'' ``unknown bus,'' ``van-based bus,'' ``school
bus,'' and ``transit bus.'' Due to the intended scope of this
rulemaking, NHTSA focused on only the first three categories.
To assure the dataset was complete, NHTSA also reexamined the FARS
body types to check to make sure all medium-size buses were included in
the analysis. There had been a change in FARS body codes in 2010. Prior
to 2010, van-based buses with GVWRs less than or equal to 10,000 lb
were coded as body type code 21, ``large van.'' In 2010, body code 55
was added to the FARS coding manual (van-based bus with a GVWR greater
than 4,536 kg (10,000 lb)). With that change, NHTSA considered whether,
for the FARS data files before 2010, it was possible that some van-
based buses with a GVWR greater than 4,536 kg (10,000 lb) were
classified under body code 21. Consequently, NHTSA searched for crashes
involving body code 21 with a GVWR greater than 10,000 lb and with a
bus use codes of ``intercity,'' ``charter/tour,'' ``transit/commuter,''
``shuttle'' \53\ to see if there were any other rollover crashes
involving types of vehicles that could be considered ``medium-size
buses.'' We identified three rollover crashes, as shown in Table 9
below.
---------------------------------------------------------------------------

\53\ FARS has bus use categories of not a bus, school,
intercity, charter/tour, transit/commuter, shuttle, modified for
personal/private use, not reported, and unknown. Among these bus use
categories, the large vans that were used as charter/tour,
intercity, commuter, and shuttle were relevant to this rulemaking.
Therefore, only the large vans with these bus use codes were
included.
---------------------------------------------------------------------------

Table 9 below shows the number of medium-size bus crashes with a
fatality, over a fifteen-year period.

Table 9--Fatal Bus Occupant Crashes of Medium-Size Buses (GVWR 10,000 lb to 26,000 lb) That are Non-OTRBs, by
the Body Type and the Crash Mode
[FARS 2004-2018]
----------------------------------------------------------------------------------------------------------------
Body type Rollover Frontal Side Rear Total
----------------------------------------------------------------------------------------------------------------
Other bus....................... 7 8 3 1 19
Unknown bus..................... 3 2 0 0 5
Van-based bus................... 9 20 8 2 39
Large van (used as intercity, 3 6 5 2 16
tour, commuter, or shuttle
buses).........................
-------------------------------------------------------------------------------
Total....................... 22 36 16 5 79
----------------------------------------------------------------------------------------------------------------

The data show that there were 79 fatal medium-size bus crashes
between 2004 and 2018, of which 22 of the 79 crashes were rollover
crashes. For the purposes of determining the safety need of applying
FMVSS No. 227 to medium-size buses, NHTSA will focus only on rollover
crashes, as the harm the standard is intended to address, and the
countermeasures that will be installed pursuant to that harm, only
result from rollovers.
Table 10, below, shows the total number of medium-size bus
fatalities attributable to various crash types.

[[Page 74283]]

Table 10--Fatalities in Medium-Size Buses by Body Type, Crash Mode, and Occupant Type
[FARS 2004-2018]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rollover Front Side Rear All types
Body type ---------------------------------------------------------------------------------------------------- Total
Driv Pass Driv Pass Driv Pass Driv Pass Driv Pass
--------------------------------------------------------------------------------------------------------------------------------------------------------
Other bus................................. 1 18 5 7 1 2 0 1 7 28 35
Unknown bus............................... 0 6 1 1 0 0 0 0 1 7 8
Van-based bus............................. 4 7 12 28 1 8 1 1 18 44 66
Large van (used as intercity, tour, 1 8 3 7 0 7 1 2 5 24 29
commuter, or shuttle buses)..............
-------------------------------------------------------------------------------------------------------------
Total (above)......................... 6 39 21 43 2 17 2 4 31 103 134
--------------------------------------------------------------------------------------------------------------------------------------------------------

For the three relevant medium-size bus types and the large vans
used as buses, there were 45 total fatalities (6 driver fatalities and
39 passenger fatalities) in rollover crashes for the fifteen-year
period. Over the 15-year period 2004-2018, there were an average of 1.5
fatal medium-size bus rollover crashes, with an average of 3.0 bus
occupant fatalities per year.These values are small compared to those
of large buses. According to data from FARS 2004-2018, there was an
average of 3.7 fatal rollover crashes involving large buses (GVWR
greater than 11,793 kg (26,000 lb)) (including OTRBs), resulting in an
average of 11.7 occupant fatalities per year. There are significantly
higher average rates of annual fatal crashes and fatalities for large
buses compared to medium-size buses.
While the average rates of annual fatal crashes and fatalities for
large buses are significantly higher than those of medium-size buses,
the fleet size of large buses is significantly smaller than that of
medium-size buses. There are an estimated 2,200 large buses (GVWR
greater than 11,793 kg (26,000 lb)) (including OTRBs) produced
annually, compared to approximately 15,000 buses with a GVWR between
4,536-11,793 kg (10,000-26,000 lb) produced annually.\54\ Table 11,
below, summarizes these figures.
---------------------------------------------------------------------------

\54\ Evaluation of the Market for Small-to-Medium-Sized Cutaway
Buses, Federal Transit Administration Project#: M1-26-7208.07.1,
December 2007, available at <a href="https://www.transit.dot.gov/sites/fta.dot.gov/files/docs/AnEvaluationofMarketforSmalltoMediumSizedCutawayBuses.pdf">https://www.transit.dot.gov/sites/fta.dot.gov/files/docs/AnEvaluationofMarketforSmalltoMediumSizedCutawayBuses.pdf</a>, last
accessed November 04, 2016.
---------------------------------------------------------------------------

These data mean that there is a considerable disparity between the
fatal rollover crash involvement for large buses versus medium-size
buses. Not only are large buses involved in more than twice as many
rollover crashes on average annually, they also have about four times
the number of occupant fatalities annually in rollover crashes than
medium-size buses. Further, taking into consideration the almost seven-
fold difference in annual production between large buses and medium-
size buses (the annual production of large buses is about 1/7th of the
annual production of medium-size buses), the safety need for FMVSS No.
227 is substantially higher for large buses than for medium-size buses.

Table 11--Summary Statistics for Fatal Rollover Crashes and Occupant Fatalities for Large Buses (Including all
OTRBs) and Medium-Size Buses
[From 2004 to 2018 (FARS)]
----------------------------------------------------------------------------------------------------------------
Avg. annual Avg. annual
Bus size rollover rollover Avg. annual
crashes fatalities fleet sales
----------------------------------------------------------------------------------------------------------------
Large Bus (greater than 26,000 lb GVWR) and all OTRBs........... 3.7 11.7 2,200
Medium-Size Bus (GVWR of 10,000-26,000 lb)...................... 1.5 3.0 15,000
----------------------------------------------------------------------------------------------------------------

With regard to the question whether there is a safety need to apply
FMVSS No. 227 to medium-size buses, NHTSA's answer is no, the data do
not show such a need at this time. The difference between the fatal
rollover crash involvement between large and medium-size buses may be
attributable to medium-size bus designs (e.g. , medium-size buses may
have a lower center of gravity compared to heavy buses, affecting crash
involvement and/or severity, or have better vehicle controllability for
a variety of reasons), or may reflect a difference in how the buses are
used. Regardless, the data dissuade NHTSA from applying FMVSS No. 227
in a one-size-fits-all manner to all buses. NHTSA concludes there is
not a substantial safety need to apply the standard to medium-size
buses.
NHTSA does not concur with NTSB's view that the BIFA database
provides more relevant statistics than NHTSA's database. The BIFA
database only includes data up to 2010, and so more recent crash data
are not available. Since 2010, NHTSA has improved the accuracy of its
crash data collection on buses and has expanded the bus category to
include van-based buses. NHTSA's updated analysis using the FARS data
files more accurately includes the mid-size bus crash information.
NTSB stated that the statistics from BIFA indicate that 128 medium-
size buses were involved in fatal crashes, resulting in 58 occupant
fatalities between 2000-2009. This information does not show whether
these crashes were rollover crashes (the crashes relevant to this
rulemaking), or whether the 58 occupants were killed in rollovers.
Despite the lack of specific data about the nature and severity of the
crashes, NHTSA undertook an analysis assuming that all the crashes NTSB
referenced were rollover crashes, and that all 58 fatalities were
attributable to rollovers. NHTSA found that, even with this assumption,
the data still show a large disparity between the rollover crashes
associated with large buses versus medium-size buses. Even if all 58
fatalities were attributable to rollover crashes, such crashes would
contribute

[[Page 74284]]

to, on average, 5.8 deaths annually (58 fatalities/10 years). In this
hypothetical scenario, large buses would still be associated with 1.3
times the number of fatalities compared to medium-size buses each
year--while the annual production of large buses would continue to be
around 1/7th of the annual production of medium-size buses. Thus, even
when factoring in the crash data suggested by NTSB and making
assumptions about the data that likely includes more crashes and
fatalities than actually occurred in medium-size buses, the data again
show an absence of a safety need for applying FMVSS No. 227 to medium-
size buses.
For the reasons above and in the NPRM, NHTSA declines to extend
FMVSS No. 227 to medium-size buses.
CIAL Comment
CIAL argued that the proposed standard should apply to medium-size
paratransit buses because buses meeting the proposed standard would be
safer for passengers. It indicated it has been researching medium-size
paratransit buses designed to meet FMVSS No. 220 \55\ and found that
buses meeting FMVSS No. 220 fail a dynamic rollover test based ``on the
concept of survival space.'' The commenter stated that six buses it
tested showed a failure mode ``in which a weak frontal structure
allowed for excessive deformation to occur in the front portion of the
bus body.''
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\55\ The requirements in FMVSS No. 220 apply to school buses.
The test in FMVSS No. 220 places a uniformly distributed vertical
force pushing directly downward on the top of the bus with a platen.
---------------------------------------------------------------------------

Agency Response
NHTSA declines to make the suggested change. CIAL's comment did not
provide a basis to conclude there is a safety need to adopt the FMVSS
No. 227 test for medium-size buses. (See response, above, to NTSB on
this issue.) CIAL states that its evaluation using finite element
models of medium-size paratransit buses shows that paratransit buses
meeting FMVSS No. 220 failed to meet a ``survival space'' criterion of
a Florida state vehicle standard. While CIAL's comparison of the
performance of paratransit buses under the requirements in FMVSS No.
220 and ECE R.66 was based on simulations, NHTSA conducted the physical
tests specified in the two standards on the same large bus models.
NHTSA's rollover testing of motorcoaches indicated that large buses
that did not meet the ECE R.66 survival space requirement also failed
the FMVSS No. 220 requirements.
Additionally, as noted earlier, over the 15-year period 2004-2018,
there were an average of 1.5 fatal medium-size bus rollover crashes,
with an average of 3 bus occupant fatalities per year. These data apply
to all medium-size buses and therefore, the average annual number of
rollover crashes and fatalities associated with medium-size paratransit
buses would be extremely small. The fact that the vehicles did not meet
the survival space criterion is not commensurate with a need to apply
FMVSS No. 227 to the vehicle type at the FMVSS level. We decline to
make the requested change, for the reasons provided above and in the
NPRM.

b. Large Buses

Entertainer Buses
NHTSA proposed to apply FMVSS No. 227 to all OTRBs as they were
defined in MAP-21. In doing so, NHTSA intended to cover all the buses
Congress directed the agency to address in MAP-21, regardless of GVWR.
Comments Received
Hemphill and NiteTrain, manufacturers and operators of over-the-
road entertainer buses, expressed concern about the test burdens on
small final-stage manufacturers of these vehicles, and suggested
excluding entertainer buses from the standard. Prevost, a manufacturer
of both complete motorcoaches and incomplete vehicles (``shells''),
also commented in favor of excluding entertainer buses. According to
Hemphill and NiteTrain, their entertainer buses are built from
incomplete bus shells purchased from Prevost. The shells consist of the
window exits, roof exits, sidewall, and roof structure.
NiteTrain and Hemphill stated that since they do not alter the
safety structure of their purchased motorcoach shells, any compliance
with the new standard should be the responsibility of the shell
manufacturer. ABA commented that NHTSA should consider entertainer
buses a distinct type of motor vehicle and decide ``on a case-by-case
basis, the extent to which each element of the motorcoach safety
requirements should be made applicable.''
Agency Response
NHTSA has decided not to apply FMVSS No. 227 to over-the-road
perimeter-seating buses. The agency's decision to scale back the scope
of FMVSS No. 227 is based on an analysis of safety need, and not on a
finding that small manufacturers cannot certify compliance with the
standard. There are ways small manufacturers may certify to FMVSS No.
227 that would not impose undue burdens on the manufacturers. For a
discussion of those options, see the August 6, 2014 NPRM preceding this
final rule (79 FR 46116-46117), and the Regulatory Flexibility Act
analysis below in this final rule.
Instead, NHTSA has reassessed the need to apply FMVSS No. 227 to
OTRBs with perimeter seating after considering that non-OTRBs with
perimeter seating are excluded from the standard. NHTSA does not find a
reason to distinguish between OTRB with perimeter seating and non-OTRB
with perimeter seating, when the safety data indicate no relevant
differences between the vehicles based on safety need. OTRB with
perimeter seating do not present a greater risk of injury due to the
failure of the structural integrity of the buses compared to non-OTRBs
with perimeter seating.
Section 32703(a) of MAP-21 mandated NHTSA to prescribe a seat belt
rule for lap/shoulder belts for motorcoaches (i.e. , which MAP-21
basically defined as over-the-road buses, except transit buses and
school buses) and did not provide NHTSA discretion in applying the
requirement. Thus, the 2013 seat belt rule issued pursuant to section
32703(a) applied uniformly to all over-the-road buses. NHTSA also
applied the rule to non-OTRBs, but had discretion to draw distinctions
among buses in that bus category, as appropriate. NHTSA drew on that
discretion to design a rule that excluded non-OTRBs with perimeter
seating from the belt requirement, based on an absence of a safety need
for the belts.
NHTSA drafted the FMVSS No. 227 NPRM preceding this final rule to
apply the proposed structural integrity requirements to the buses that
were subject to the lap/shoulder belt requirements adopted by the 2013
MAP-21 final rule. The agency believed that there was a need to ensure
enhanced structural integrity of the interior of buses subject to the
seat belt rule, to better protect the restrained occupants who, due to
the belts, will be retained in the bus interior.\56\ The NPRM excluded
from proposed FMVSS No. 227 perimeter seating buses, but not if they
were OTRBs.\57\
---------------------------------------------------------------------------

\56\ 79 FR 46096, col. 1.
\57\ The proposed definition of ``perimeter-seating bus'' is ``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.'' (S3.) NHTSA excluded perimeter-seating buses that were not
over-the-road buses from the seat belt rule because perimeter-
seating buses are often used in shuttle operations.

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[[Page 74285]]

However, after considering the comments, NHTSA has decided not to
apply FMVSS No. 227 to perimeter-seating buses as a class. In the seat
belt final rule, NHTSA applied the belt requirement to OTRBs with
perimeter seating, and not to non-OTRB with perimeter seating, because
of a statutory mandate to require the seat belts in all OTRBs. There is
no such mandate about the applicability of FMVSS No. 227. NHTSA has
discretion under MAP-21 (section 32703(b)) to determine whether a
rollover structural integrity standard and an anti-ejection portal
improvement standard meet the requirements and considerations of
section 30111(a) and (b) of the Safety Act.\58\ After considering
section 30111(a) and (b), NHTSA has decided it would not be appropriate
to distinguish between perimeter-seating buses depending only on
whether they are OTRBs or not.
---------------------------------------------------------------------------

\58\ NHTSA is authorized under the Vehicle Safety Act to issue
motor vehicle safety standards that ``shall be practicable, meet the
need for motor vehicle safety, and be stated in objective terms''
(49 U.S.C. 30111(a)). When prescribing a motor vehicle safety
standard, NHTSA considers, inter alia, relevant available motor
vehicle safety information, whether a standard is reasonable,
practicable, and appropriate for the particular type of motor
vehicle or motor vehicle equipment for which it is prescribed, and
the extent to which the standard will carry out the purpose and
policy of the Act, i.e. , reduce traffic accidents and deaths and
injuries resulting from traffic accidents (49 U.S.C. 30111(b)).
---------------------------------------------------------------------------

NHTSA developed its motorcoach safety plan to protect the public
against unreasonable risk of death or injury in high-occupancy
vehicles.\59\ In the Executive Summary in NHTSA's 2013 seat belt final
rule, NHTSA stated: ``One of the guiding principles NHTSA considers in
determining the priorities of our rulemaking projects is to protect the
public against unreasonable risk of death or injury in high-occupancy
vehicles. In 2007, NHTSA published a comprehensive plan to research
improvements to bus safety, entitled, `NHTSA's Approach to Motorcoach
Safety.' '' [Footnote omitted.] In contrast, perimeter-seating OTRBs
are low-occupancy vehicles compared to conventional inter-city buses
that have primarily forward-facing seating. NHTSA has decided to
exclude both OTRBs with perimeter-seating and non-OTRBs with perimeter-
seating from this final rule, based on an absence of a safety need to
include the buses. It is reasonable not to distinguish between the two
kinds of perimeter-seating buses in applying the standard to the
vehicles because of an absence of reasons to distinguish. This final
rule treats both kinds of buses with perimeter seating (OTRB and non-
OTRB) the same under FMVSS No. 227.
---------------------------------------------------------------------------

\59\ 78 FR 70416, November 25, 2013. The preamble also makes
repeated reference to ``high-occupancy'' buses in its analyses of
crash data involving the subject buses.
---------------------------------------------------------------------------

It should be noted that Hemphill and NiteTrain indicate that they
obtain a bus ``shell'' from an incomplete vehicle manufacturer, such as
Prevost.\60\ Prevost manufactures both complete motorcoaches and
incomplete vehicles (``shells''). The agency believes that, following
establishment of this FMVSS No. 227, Prevost will offer for sale in the
U.S. incomplete vehicle shells that meet the structural integrity
requirements of ECE R.66 (the standard on which FMVSS No. 227 is
based), because most of their final-stage manufacturer customers will
produce buses that are subject to FMVSS No. 227. For customers that
produce buses that are excluded from FMVSS No. 227, for liability and
competitive marketing reasons, it would make little commercial sense to
offer shells that do not meet ECE R. 66 to customers, or for customers
to buy such shells. Thus, even if perimeter-seating buses are excluded
from FMVSS No. 227, manufacturers will likely produce buses using these
ECE R.66 shells, which will result in vehicles that provide
significantly improved structural integrity in a rollover crash. When
the bus superstructure is strengthened to meet FMVSS No. 227 there will
be less deformation of the bus structure and reduced torsional loads on
interior structures, such as partitions, and reduced risk of intrusion
into the occupant space. This means that perimeter-seating buses, even
though excluded from the standard, will provide enhanced structural
integrity in a rollover. Hemphill commented that partitions will ``add
support to the roof of our coaches and significantly increase the
roof's integrity'' and will ``significantly reduce any intrusion into
the survival space'' in a rollover. While the commenter did not provide
data or evidence to support its claim, NHTSA concurs that minor
modifications to the vehicle structure, such as by installation of
partitions, will not degrade the integrity of the superstructure of the
bus, and that even these perimeter-seating buses will provide
protection against roof collapse in a rollover.
---------------------------------------------------------------------------

\60\ Incomplete vehicle manufacturers such as Prevost are large
manufacturers.
---------------------------------------------------------------------------

Prison Transport Buses
The NPRM proposed to apply FMVSS No. 227 to prison transport buses
(78 FR 70416). MCI, a manufacturer of prison transport buses, disagreed
with this proposal. MCI expressed concern about the need to partition
these buses to provide cells, believing that each customer's unique
cell configuration could affect the test results of the standard. MCI
states it would not be practicable to fulfill a one-of-a-kind bus order
by building a second bus for testing to meet MCI's certification
responsibilities.
Agency Response
NHTSA agrees to exclude prison buses from FMVSS No. 227 but not for
the reason given by MCI. Due to the nature of the vehicle type, prison
vehicle interior configurations/partitions may vary considerably.
However, NHTSA does not require the kind of certification burden MCI
describes. A manufacturer does not have to build a replicate vehicle to
test to enable the manufacturer to certify compliance with the
standard. A discussion of various certification methods available to
manufacturers can be found in the August 6, 2014 NPRM preceding this
final rule (79 FR 46116-46117), and in the Regulatory Flexibility Act
analysis below in this final rule.
NHTSA is excluding prison buses because the FMVSS No. 227 is not
appropriate for the bus type. The agency does not know how many prison
buses are manufactured each year, but does not believe there is a
substantial number of such vehicles produced. Regardless of the number
of vehicles produced, bus superstructures sold in the U.S. are likely
to be strengthened to meet FMVSS No. 227 after this final rule becomes
effective. With the strengthened superstructures, there will be less
deformation of the bus structure and reduced torsional loads on
interior structures, such as partitions. Thus, the agency has not found
justification to apply FMVSS No. 227 to prison buses, as minor
modifications to the vehicle structure, such as by installation of
partitions, are unlikely to affect the structural integrity of the
vehicles.
Double-Decker Buses
The NPRM proposed to apply FMVSS No. 227 to double-decker buses.
Buses with open-roof sections would not have the open section assessed
for compliance but the closed-roof sections would be. Double-decker
buses with closed-roof sections on the lower and top levels would have
both levels assessed for compliance. Since we saw no difference in the
potential safety risks of double-decker buses and other large buses
covered under our proposal, we proposed applying FMVSS No. 227 to the
bus type.

[[Page 74286]]

Comments Received
NTSB and Coach USA (a large motorcoach operator) supported applying
FMVSS No. 227 to double-decker buses. NTSB stated it would be
appropriate to test the portions of the bus where bus structure could
intrude on the vehicle occupants. Coach USA supported applying the same
requirements to lower/enclosed sections of open-top double-decker
buses, and stated that its double-decker buses already comply with the
ECE R.66 test. In contrast, Van Hool stated that in Europe ECE R.66 can
be applied to double-deckers only at the request of the manufacturer
and referenced a document to argue that the number of fatalities that
are attributable to double-decker buses is lower than those
attributable to other buses.
Agency Response
This final rule applies FMVSS No. 227 to double-decker buses as
proposed. Double-decker buses are being used for intercity/interstate
transport of large numbers of passengers.\61\
---------------------------------------------------------------------------

\61\ See e.g., Megabus website, <a href="http://us.megabus.com/">http://us.megabus.com/</a>, last
accessed October 24, 2016.
---------------------------------------------------------------------------

We do not concur with Van Hool that there should not be a safety
concern with double-decker buses. The document that Van Hool referenced
to support its view consists only of meeting notes from a UN ECE
informal working group meeting on ECE R.66.\62\ The meeting notes
stated that a representative from Spain presented information about bus
crashes, but the notes did not include statistics about double-decker
buses. Further, the notes included a point made by a person from the
International Road and Transport Union expressing concern that the
increased mass of the superstructure of a double-decker bus above the
vehicle's center of gravity might suggest that the double-decker bus
should be subject to the ECE R.66 requirements. We do not see any
information in the meeting notes that suggested that the safety risk is
lower for these types of buses.
---------------------------------------------------------------------------

\62\ <a href="https://www.unece.org/fileadmin/DAM/trans/doc/2008/wp29grsg/GRSG-95-07e.pdf">https://www.unece.org/fileadmin/DAM/trans/doc/2008/wp29grsg/GRSG-95-07e.pdf</a> (last accessed Feb-23-2017).
---------------------------------------------------------------------------

Further, we believe that the design characteristics and physics of
double-decker buses suggest that double-decker buses are at least as
susceptible to the rollover crash risk as the other buses covered under
this final rule. Double-decker buses can have GVWRs fifteen to twenty
percent greater than single-deck OTRBs.\63\ A Swedish study \64\ on
occupant fatalities in bus crashes concluded that--
---------------------------------------------------------------------------

\63\ Van Hool TX Luxury Touring Coach GVWRs are 50,700 lb (40''
vehicle length) and 54,000 lb (45'' vehicle length). Van Hool TD925
double-decker buses are GVWR 62,000 lb (45'' vehicle length).
Vehicle data from <a href="https://www.abc-companies.com/">https://www.abc-companies.com/</a> com/, last accessed
October 24, 2016.
\64\ Albertsson, Pontus; Occupant Casualties In Bus And Coach
Traffic; 2005; ISBN 91-7305-829-7.

The height of a double-deck vehicle may be 60-80 [centimeters]
higher than a corresponding single deck vehicle. In case of a
rollover with a double-deck vehicle, the greater [the] distance from
the [center] of gravity in the upper compartment[,] the greater
[the] increase of the rotation velocity. This, in turn, will
increase the [ground] impact [leading to] greater risk for injuries
---------------------------------------------------------------------------
as a consequence.

Thus, the available information does not support Van Hool's
contention that there is little crash risk associated with double-
decker buses. While the agency seeks to harmonize with ECE regulations
to the extent possible, we believe applying FMVSS No. 227 to double-
decker buses will meet a safety need in this country. According to
Coach USA, its double-decker buses already meet the ECE R.66
requirements, which illustrates the practicability of the buses''
meeting FMVSS No. 227.
This final rule makes a slight clarification in the regulatory text
of FMVSS No. 227 relating to double-decker buses. The standard would
not apply to a level of a bus that does not have a permanent roof over
the level, such as the upper level of a double-decker bus that does not
have a permanent roof over the upper level. However, a double-decker
bus that is open-top in the rear half of the bus but permanently
closed-top for the front half of the bus is subject to the requirements
of FMVSS No. 227 for the front half of the top of the bus (as well as
for the entire enclosed lower section of the bus).

IX. School Bus Derivative Buses

Daimler Trucks North America (DTNA) \65\ and IC Bus, LLC (IC Bus)
manufacture school and commercial buses and certify the vehicles to
FMVSS No. 220, ``School bus rollover protection,'' and FMVSS No. 221,
``School bus body joint strength.'' The commenters suggest that NHTSA
permit buses meeting FMVSS No. 221 the option of meeting FMVSS No. 220
rather than FMVSS No. 227. They state that the buses are similar in
appearance to school buses but are sold for non-school related
purposes. The commenters contend that the operating environment for
these buses is closer to that of school buses than intercity buses and
that the vehicles should be subject to the school bus safety standards
for rollover protection (FMVSS No. 220) and joint strength (FMVSS No.
221) rather than FMVSS No. 227.
---------------------------------------------------------------------------

\65\ DTNA states that it manufactures school buses under the
Thomas Built Bus brand.
---------------------------------------------------------------------------

Agency Response
We agree with the commenters and have excluded school bus
derivative buses from FMVSS No. 227. This is because the buses already
provide a survival space by meeting FMVSS No. 220, ``School bus
rollover protection,'' and do not need to meet the requirements of
FMVSS No. 227.
FMVSS No. 227 defines ``school bus derivative buses'' in a manner
reflecting that the buses are built on a school bus platform for sale
in the U.S. The buses have safety systems that are identical to school
buses regarding their fuel systems, bus body joint strength, emergency
exits and roof crush resistance. The vehicles could be certified as
meeting the FMVSSs for ``school buses'' if they had seating systems
meeting FMVSS No. 222, ``School bus seating and passenger protection''
(49 CFR 571.222), and school bus lights and stop arms meeting FMVSS No.
108 and No. 131, respectively. NHTSA is excluding the buses to avoid
redundancy in the FMVSSs. Thus, the definition is designed to exclude
only vehicles that could be certified to the school bus FMVSSs and not
other large buses.
DTNA and IC Bus argue that their school bus derived commercial
buses operate under conditions more similar to those of school buses
than OTRBs. The ``applications'' in which the commercial buses are used
are described by DTNA as ``church activity, retirement community,
college campus, boys and girls club, parks and recreation department
and airport shuttles.'' IC Bus echoes that description and adds
``support of emergency responders.'' NHTSA agrees that these
applications describe usage that is more local in nature than that of
intercity OTRBs. NHTSA recognizes, however, that once purchased,
operators of the vehicles could use school bus-derivative buses in ways
other than that described by DTNA and IC Bus, so in analyzing the
commenters'' suggestion NHTSA must consider the likelihood that the
buses may not be used like school buses.
It is a fact that FMVSS No. 220 has a record of rollover safety in
school buses. The standard has been applied to school buses since 1977.
School bus derivative buses are already manufactured to meet the school
bus roof crush resistance

[[Page 74287]]

requirements in FMVSS No. 220. NHTSA believes these buses already have
improved roofs and roof supports that substantially improve the
resistance of the roofs to deformation and intrusion compared to buses
that do not meet FMVSS No. 220.\66\ To avoid redundancy in the FMVSSs,
this final rule permits these buses the option of meeting FMVSS No. 220
when tested in accordance with the test procedures of FMVSS No. 220,
instead of the ECE R.66-based rollover test requirements of FMVSS No.
227.
---------------------------------------------------------------------------

\66\ In addition, as DTNA and IC Bus point out, the vehicles
also meet FMVSS No. 221, which adds to the structural integrity of
the vehicles. The purpose of FMVSS No. 221 is to reduce deaths and
injuries resulting from the structural collapse of school bus bodies
in crashes.
---------------------------------------------------------------------------

The agency is not permitting buses other than school bus derivative
buses to meet FMVSS No. 220. Buses other than school bus derivative
buses have been designed such that they have a higher center of gravity
and/or utilize larger windows than school buses. These characteristics
can lead to a higher incidence of occupant ejections during rollovers.
Thus, the dynamic rollover test in ECE R.66 affords the agency an
opportunity to set a minimum level of performance for the ejection-
mitigating features of non-school bus derivative buses, such as
emergency exits closure and side window glazing retention during a
rollover crash.

X. Performance Requirements

The NPRM proposed performance requirements that buses must meet
when subjected to a tilt rollover test. In the proposed test, the bus
is placed on a tilting platform that is 800 mm (31.50 inches) above a
smooth and level concrete surface. One side of the tilting platform
along the length of the vehicle is raised at a steady rate of not more
than 5 degrees/second until the vehicle becomes unstable, rolls off the
platform, and impacts the concrete surface below with its roof leading
edge. The major points of this testing method involve a quarter-turn
roll of the bus onto its side (so that it strikes the top corner of the
bus superstructure on a rigid surface) and ballasting the vehicle to
simulate the load that the bus would be carrying in a rollover crash.
This test creates a high-severity test condition that encompasses the
majority of real-world bus rollovers.

a. Severity of the Rollover Test

EPGAA, Advocates, the families of bus crash victims (the families),
and Ms. Stoos, express concern that the proposed test evaluation is not
severe enough to replicate the conditions of real-world bus rollovers.
The families and Advocates state that the rollover test should include:
Vehicle rollovers greater than 90 degrees (one quarter roll); high
vehicle speed prior to rollover; embankments; and impacts that may
occur after the rollover. Advocates references a 2007 glazing retention
test development study commissioned by NHTSA and Transport Canada to
illustrate its point (``Motor Coach Glazing Retention Test Development
For Occupant Impact During A Rollover,'' Martec Technical Report # TR-
06-16, Rev 4, August 2006 (``Martec study'') \67\ ).
---------------------------------------------------------------------------

\67\ Docket No. NHTSA-2002-11876-0015.
---------------------------------------------------------------------------

Agency Response
NHTSA does not agree with the commenters' argument that FMVSS No.
227's test is not a reasonable representation of a severe rollover
crash. As discussed below, research papers, test reports, simulation
analyses, and reports on the efficacy of the ECE R.66 test support the
implementation of the test.
FMVSS No. 227's test is highly stringent, accounting for the
potential real-world rollover crash forces that are imparted on the bus
superstructure in a rollover crash. The test creates a force near the
top corner of the bus in the transition from the sidewall to the roof.
This application of force is representative of a bus rolling over into
a drainage ditch along a highway; however, in the FMVSS No. 227 test,
the bus strikes a hard surface that is more rigid than the typical
earthen drainage ditches along the roadside. The hard surface results
in the energy from the rollover being absorbed by the bus and not
shared between the bus and the ground. This hard surface contact makes
FMVSS No. 227's rollover test more stringent than similar rollovers
into earthen embankments. Matolcsy, M. (2007), ``The Severity of Bus
Rollover Accidents,'' 20th International Technical Conference for the
Enhanced Safety of Vehicles, Paper 989, Lyon, France.\68\ The test also
gives the agency a repeatable, reproducible, and practical method to
evaluate bus structural integrity during rollover crashes.
---------------------------------------------------------------------------

\68\ Available at: <a href="https://www-esv.nhtsa.dot.gov/Proceedings/20/07-0152-O.pdf">https://www-esv.nhtsa.dot.gov/Proceedings/20/07-0152-O.pdf</a>.
---------------------------------------------------------------------------

It can appear to the eye that crashes involving multiple quarter-
turn rolls along the ground are more severe than a single quarter-turn
rollover onto rigid pavement that ends instantly, all other things
being equal. The significant difference is that the multiple quarter-
turn roll loads an entire side, then the roof, then the other side,
next the wheels/suspension/floor, and so on until the bus comes to a
rest. The multiple quarter-turn rollover dissipates the crash energy
across major portions of the vehicle structure over a relatively long
duration. The vehicle structure in a multiple quarter-turn crash is not
managing or absorbing all of the crash energy at once. Single quarter-
turn rollovers, in which the crash forces are reacted over a short
duration by relatively weak localized components of the vehicle
structure, require the entire vehicle structure to be stronger.
Therefore, the more stringent rollover test is one in which the energy
of the crash is applied instantaneously, such that the vehicle needs to
manage and absorb all the energy applied at the same time.
The demanding nature of the ECE R.66 test incorporated into FMVSS
No. 227 is discussed at length in the 2007 report, which evaluated the
sufficiency of the test for adoption into R.66.\69\ The report's author
notes that early work on ECE R.66 considered different types of
rollover scenarios during deliberations to ``find an appropriate
standard approval rollover test.'' For the issue of conducting a test
with multiple turns (i.e., the bus rolling more than a quarter-turn),
the study concluded that the ECE R.66-based test imparts more loads on
the bus superstructure than other potential tests that included
multiple turns. This was found even though the tests with multiple
turns began with a bus raised higher from its final end of test resting
place--i.e., the other tests began with greater potential energy than
the ECE R.66-based test.
---------------------------------------------------------------------------

\69\ Matolcsy, M. (2007), supra.
---------------------------------------------------------------------------

Figure 3, below, shows the three rollover tests that were analyzed
during development of ECE R.66.

[[Page 74288]]

[GRAPHIC] [TIFF OMITTED] TR29DE21.002

The study compared the quarter-turn ECE R.66 test to other tests in
which the bus traveled a greater distance during the test and rolled
multiple times. The research conducted a series of tests under three
test scenarios using the same bus type. In the end, the research showed
test ``c,'' which is essentially ECE R.66, produced results that
imparted the greatest loads on the bus superstructure. The test series
further showed that bus reinforcements to provide survival space in
test ``b'' needed further reinforcement to provide sufficient survival
space in test ``c.'' From these data, it was found that, while a test
could simulate a crash with more total energy (e.g., test conditions
``a'' and ``b'' under which the bus begins the test with higher
potential energy), the long dissipation of that energy over multiple
rolls during the crash significantly reduces the damage imparted to the
bus superstructure during the test.
---------------------------------------------------------------------------

\70\ Id.
---------------------------------------------------------------------------

NTSB and Advocates request that the agency consider a test
involving more than a quarter-turn rollover. The commenters did not
elaborate on how many more turns of a vehicle rollover they would like
the agency to adopt. The agency has no data on the number of quarter-
turns that occur in a bus rollover since the FARS database does not
capture that crash detail. Nonetheless, the Matolcsy report, supra,
explains how buses developed to meet the requirements of ECE R.66 have
maintained survival space when those buses have experienced rollovers
beyond a quarter-turn and down embankments. This information suggests
that FMVSS No. 227 will lead to buses capable of providing bus
passengers with a survival space and lowered risk of ejection during
rollover crashes greater than a quarter-turn.
The Matolcsy report provides additional examples of real-world
improvements manufacturers have made to buses in response to ECE R.66
requirements, including photographs of how bus interior compartments
looked post-crash before and after application of ECE R.66 to the
vehicles. A bus that was not designed to comply with ECE R.66
experienced structural collapse in a rollover crash with one and a half
full 360 degree rolls down a 6-meter embankment similar to the one
depicted above in Figure 3(b). In contrast, a bus designed to meet ECE
R.66 requirements was able to maintain adequate survival space in a
rollover crash with two and a quarter full 360 degree rolls down a 9-10
meter embankment similar to the crash depicted in Figure 3(b) above.
In its comments, Advocates references a research project on
motorcoach window glazing in which the research used finite element
(FE) models to compare the loads on the bus structure in different
simulation tests where the bus carried different lateral speeds into
its crash with the impact surface.\71\ The simulation scenarios in the
research included: (1) No lateral speed with 800 mm drop (replicating
ECE R.66), (2) 30 kilometers per hour (km/h) lateral speed with 400 mm
drop, and (3) 30 km/h lateral speed with 800 mm drop.\72\
---------------------------------------------------------------------------

\71\ See Comment from the Advocates for Highway Safety, Docket
No. NHTSA-2014-0085-0016, page 5 and 6. The comment references the
2007 NHTSA report, National Motor Coach Glazing Test Development for
Occupant Impact during a Rollover. (NHTSA-2002-11876).
\72\ See Martec Technical Report # TR-06-16; ``Motor Coach
Glazing Retention Test Development For Occupant Impact During A
Rollover,'' (Joint NHTSA and Transport Canada Program; Final
Report); Docket No. NHTSA-2002-11876-0015.
---------------------------------------------------------------------------

Advocates refers to a statement by the researchers that the ECE
R.66 test is not the most stringent test condition. NHTSA notes that
the statement reflected only a preliminary finding of Phase I of the
study and was later corrected.\73\ The preliminary results in Phase I
were refined in Phase II of the study. After improving their analysis
methodology and conducting the simulation again in Phase II, the
researchers conclude that the ECE R.66 test is the more stringent test
when compared to tests that incorporated a lateral speed.\74\ As can be
seen in the Table 12 data, the ECE R.66 rollover produced higher
rollover contact forces than rollover simulations with the ECE R.66
drop height and an initial lateral velocity.
---------------------------------------------------------------------------

\73\ The authors stated that the models used for the first phase
were not detailed and were ``only expected to provide rough-order-
of-magnitude roof/ground [contact] forces.''
\74\ Id.

[[Page 74289]]

Table 12--Comparison of Roof Impact Forces \75\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rollover Scenario
-----------------------------------------------------------------------------------------------------------------------
No. 1 (ECE R.66) No. 2 (400 mm) No 3. (800 mm)
-----------------------------------------------------------------------------------------------------------------------
Phase I Current Phase I Current Phase I Current
--------------------------------------------------------------------------------------------------------------------------------------------------------
Contact Surface................. Roof perimeter.... Window Posts...... Roof Perimeter & Window posts...... Roof Perimeter.... Window Posts.
Window Posts.
Peak contact Force (N).......... 4,065,900......... 2,831,593......... 4,538,964......... 2,468,656......... 3,920,160......... 2,696,370.
Average Impact Force (N)........ 1,481,100......... 1,219,995......... 2,271,342......... 891,627........... 1,960,137......... 1,149,529.
--------------------------------------------------------------------------------------------------------------------------------------------------------

When a bus traveling at highway speeds tips and begins a multiple-
turn roll, the energy in the crash will not be completely transferred
to the vehicle structure at the first impact. A significant portion of
the energy will go towards sustaining the rolling motion of the bus.
Thus, while the vehicle would sustain more impacts during this extended
rollover crash, the loads on the superstructure would be lower than the
ECE R.66-based test. Further, even if the bus turned only once at
highway speed, landed on its side, and slid on the side, the single
impact at highway speed would load an entire side of the bus structure,
rather than just a corner of the bus superstructure. This flat-faced,
wide application of the load dissipates the energy and enables the bus
to better withstand the load than the more stringent concentrated load
application of FMVSS No. 227. The friction from the sliding of the bus
on the surface of the ground also dissipates the kinetic energy of the
crash over a longer period--further reducing the load on the vehicle
superstructure In short, FMVSS No. 227 presents a severe real-world
application of crash loads on the superstructure, and does so in a
controlled, objective manner appropriate for an FMVSS compliance test.
---------------------------------------------------------------------------

\75\ Id., table from report, page 14.
---------------------------------------------------------------------------

Advocates also discuss a crash variation where the bus may hit an
embankment or other ``vertical surface'' type object. This crash
variation may or may not increase the total energy to be dissipated
during the crash, but the load concentration may change. However, even
with different potential objects loading the structure, we believe that
the loads to which the superstructure is subjected might be similar in
some respects to the loading to which the superstructure is exposed
when tested under FMVSS No. 227. While no embankment or other
``vertical surface''-type object is a part of the test, the vehicle
superstructure's loading during the test is akin to the concentrated
force that is applied when striking a ``vertical surface.'' The test
involves loading the entirety of the energy in the test onto a
concentrated section of the structure (i.e. , the corner of the roof).
Thus, we believe that FMVSS No. 227 reflects an aspect of the
``vertical surface'' and other crash variations about which Advocates
is concerned.\76\
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\76\ NHTSA also notes that, at this time, the petitioner's
request to incorporate vertical surfaces to mimic a motorcoach
accident scenario is impractical to meet. To adopt an objective,
repeatable and meaningful test maneuver that incorporates highway
speeds and vertical surfaces for the bus to impact, NHTSA should
have additional information on what speed is representative, how to
trip the bus to initiate a roll, what vertical surface objects are
representative, etc. Such information is now unavailable. Further, a
test incorporating highway speeds and vertical surfaces is currently
not practical as the test conditions are exceedingly difficult to
replicate, and pose inordinate safety risks to technicians
conducting the test.
---------------------------------------------------------------------------

For the above reasons, NHTSA concludes that the ECE R.66-based test
adopted in this final rule is an effective high-stringency test. The
test substantially increases the likelihood that large buses will
withstand the crash forces in a real-world rollover crash and provide a
survival space to occupants.\77\ FMVSS No. 227 addresses motorcoach
crashes that are more than quarter-turn crashes, without having to
expose the vehicles to the exact same conditions. Given that all
available information indicate that the FMVSS No. 227 test sufficiently
replicates a deadly rollover crash, we are adopting the ECE R.66-based
test in this final rule.
---------------------------------------------------------------------------

\77\ Advocates also points to an NTSB Preliminary Report on a
crash of a 1996 Setra Motorcoach operated by AM USA Express, Inc.
Comparing the image of that bus (post-crash) in the NTSB Preliminary
Report to a bus that NHTSA tested using ECE R.66 in research.
Advocates argues that the ECE R.66 test fails to represent real-
world crash conditions. Advocates does not present any information
regarding the roof structures of these vehicles and whether their
structures are similar enough to compare the severity of the crash
conditions. There is insufficient information to make any reasonable
conclusions comparing the crash severity in these two cases.
---------------------------------------------------------------------------

b. Intrusion Into the Survival Space

The NPRM proposed to prohibit intrusion into the ``survival
space,'' demarcated in the vehicle interior from approximately the rear
wall of the bus to 600 mm (24 inches) in front of the front surface of
the seat back of the front row seats, by any part of the vehicle
outside the survival space.
The purpose of the proposal is to guard against inadequate survival
provided to occupants, especially belted ones, due to collapsing
sidewalls, roof structure, or other objects. We intended the
requirement to complement our standard requiring seat belts for
passengers on the subject buses, to ensure that passengers retained in
their seats will have a survival space protecting them from collapsing
vehicle structure. Our research found structural intrusions into the
survival space in the tested MY 1991, MY 1992, and MY 2000 buses. The
NPRM proposed to define the vehicle survival space in a specific manner
(see S4 of the proposed standard, 79 FR 46119-46120). The NPRM also
proposed use of ``survival space templates'' in the compliance test.
Overall, commenters concurred with the survival space concept,
suggesting small changes to the proposal.
MCI suggested that the survival space requirements should account
for variations in vehicle floor heights so that the same height space
can be provided in each vehicle segment. MCI requested survival space
be defined relative to the forward and rear floor height of each
segment of the vehicle.
NHTSA does not believe there is a need to change the survival space
definition in response to MCI. The survival space definition already
accounts for variations in interior compartment floor height front-to-
rear and side-to-side in the vehicle.
However, the agency does believe it should clarify two ambiguities
in the survival space definition. First, the ``survival space''
definition is clarified by defining ``occupant compartment'' to mean a
space within the vehicle interior intended for driver and passenger
use, excluding any space occupied by fixed appliances such as bars,
kitchenettes, or toilets. Second, the definition of ``survival space''
is made clearer with regard to a forward-most seat that is not forward-
facing. The specification of the centerline used to locate the
reference point for the transverse vertical plane was not entirely
clear in the NPRM. The ``longitudinal'' centerline should be

[[Page 74290]]

specified for the most forward point on the most forward seat. Further,
the direction that the most forward seat faces will affect the relative
positioning of the transverse vertical plane to this seat. This final
rule therefore modifies the definition of survival space to specify
that the front boundary of the survival space is a transverse vertical
plane determined relative to the most forward seat \78\ in the
passenger deck when the seat is in its forward-most position and its
seat back is in the manufacturer's nominal design riding position. This
transverse vertical plane is, (1) for a forward-facing seat, 600 mm in
front of the most forward point on the longitudinal centerline of the
front surface of the seat back, (2) for a rearward-facing seat, through
the most forward point on the longitudinal centerline of the seat back,
and (3) for a side-facing seat, through the most forward point on the
seat, including the seat back, seat arm rest, and seat cushion.
---------------------------------------------------------------------------

\78\ This seat could be a passenger seat, the driver's seat, or
a temporary (jump) seat.
---------------------------------------------------------------------------

Intrusion of Items Into the Survival Space
MCI expresses concern that small glass shards falling from a window
into the survival space may be a failure per the language of S5.1 \79\
of the NPRM.
---------------------------------------------------------------------------

\79\ 79 FR 46120. The NPRM proposed the following regulatory
text (S5.1): No part of the vehicle which is outside the survival
space shall intrude into the survival space during the movement of
the tilting platform or resulting from impact of the vehicle on the
impact surface.
---------------------------------------------------------------------------

That was not NHTSA's intent in issuing this rule, but the agency
agrees the proposed language could be read to produce such an outcome.
NHTSA's intent in maintaining a survival space was to ``set a minimum
level of structural integrity for these buses, to help prevent
dangerous structural intrusions into the occupant survival space.''
\80\ The intent of the survival space requirement was to ensure ``that
the roof and sidewalls will be able to withstand the racking forces of
a rollover crash.'' \81\ The purpose of retaining the window glazing to
its mounting structure was to ``ensure that the vehicle's structural
integrity will prevent heavy glazing panels from falling into the
passenger compartment and becoming ejection portals.'' \82\ We used
``massive'' and ``heavy'' to describe the window glazing panels and
discussed a need to ``[reduce] risk of injury from falling panels of
glazing and occupant ejections.'' As NHTSA's intent was not to require
protection from ``small glass shards'' during the bus rollover, this
final rule has clarified the requirements to reflect this view, as
discussed below.
---------------------------------------------------------------------------

\80\ 79 FR 46092, August 6, 2014.
\81\ Id.
\82\ Id.
---------------------------------------------------------------------------

NHTSA is providing in FMVSS No. 227 that objects of a minute size
may intrude into the survival space. As to the size of the objects, the
commenters do not provide a suggested definition for ``small glass
shards.'' NHTSA thus turned to analyzing the Federal glazing standard
to determine how the standard describes acceptably ``small'' glass
shards regarding occupant safety. Glazing material used in motor
vehicles must meet the requirements of FMVSS No. 205, ``Glazing
materials'' (49 CFR 571.205). FMVSS No. 205 specifies that ``[g]lazing
materials for use in motor vehicles must conform to ANSI/SAE Z26.1-
1996'' \83\ unless FMVSS No. 205 provides otherwise.
---------------------------------------------------------------------------

\83\ American National Standard for Safety Glazing Materials for
Glazing Motor Vehicles and Motor Vehicle Equipment Operating on Land
Highways-Safety Standard (ANSI/SAE Z26.1-1996).
---------------------------------------------------------------------------

ANSI/SAE Z26.1-1996 allows ``small particles'' to disengage from
the glazing material during some of the laminated glazing \84\ impact
tests, though there is no express definition of ``small particles'' in
ANSI/SAE Z26.1-1996. There is a 227 g (0.5 lb) 9.14 m (30 feet) ball
drop impact test \85\ in the ANSI standard for laminated glazing. The
ball drop test allows ``total separation of glass from the reinforcing
or strengthening material'' that does ``not exceed 1935 square
millimeters (mm \2\) (3 square inches (in \2\)) on either side.''
(During the rollover testing the agency conducted in support of the
FMVSS No. 227 NPRM, laminated glazing panels did shatter, but no
discernable amount of the glazing material came free from the
interlayer material.)
---------------------------------------------------------------------------

\84\ The requirements for the tempered glazing fracture test in
the American National Standards Institute (ANSI) standard require
that ``no individual fragment free from cracks and obtained within 3
minutes subsequent to test shall weigh more than 4.25 gram (g) (0.15
ounce (oz)).''
\85\ ANSI/SAE Z26.1-1996, S5.12
---------------------------------------------------------------------------

The ANSI/SAE Z26.1-1996 maximum glazing separation size of 1935 mm
\2\ (3 in \2\) for laminated glazing evaluated using the ANSI ball drop
test is helpful in indicating ANSI's determination of the maximum size
of glazing that may enter the survival space without causing injury.
Glazing pieces 1935 mm \2\ (3 in \2\) or smaller are not massive or
heavy, and the likelihood that they will cause serious blunt trauma
injury is significantly lower compared to contact with an entire 84 kg
(185 lb) glazing panel in a crash.
However, NHTSA further considered MCI's comment that ``a failure of
a single fastener (such as a rivet) that is part of the attachment of
the parcel rack assembly could be deemed a failure of the test.'' The
agency decided that small items other than glazing pieces (e.g. , a
bolt) should be allowed to enter the survival space if small glazing
pieces are allowed. Given that the potential for injury caused by
pieces entering the survival space is a function of the mass of the
item, we decided to limit the items allowed to enter the survival space
by the mass of the item.
As to what that mass should be, we again turned to ANSI/SAE Z26.1-
1996 and glazing characteristics to start. The ANSI standard permits
pieces of laminated glazing of 1935 mm\2\ (3 in\2\) to separate (break
off) in the 227 g (0.5 lb) 9.14 m ball drop impact test. We estimate
that laminated glazing has a glass thickness of approximately 2.5 mm
for each glass layer, and a glass density \86\ of about 0.00251 g/mm\3\
(1.445 ounce (oz)/in\3\). Thus, a piece of laminated glazing of 1935
mm\2\ (3 in\2\) has a mass of approximately 12 grams (g) (0.43 oz).
Factoring in a 3 g (0.11 oz) tolerance, we are prohibiting intrusion
into the survival space by any part of the vehicle outside the survival
space other than items with a mass of less than 15.0 grams (0.53 oz).
Tempered glazing shatters into tiny pebbles that are significantly
smaller and lighter than pieces of broken laminated glazing. The
shattered pieces of tempered glazing would weigh significantly less
than 15.0 grams (0.53 oz).
---------------------------------------------------------------------------

\86\ Glass density value from <a href="https://www.saflex.com/en/AutoReduceVehicleWeight.aspx">https://www.saflex.com/en/AutoReduceVehicleWeight.aspx</a> I couldn't access this 4/20/20.
---------------------------------------------------------------------------

C. Luggage Racks and Seat Anchorages

As discussed above in this preamble, the NPRM proposed to prohibit
any anchorage of an interior overhead luggage rack or compartment or
anchorage of a vehicle seat from completely separating from its
mounting structure during the movement of the tilting platform or
resulting from impact of the bus on the impact surface. After reviewing
the comments, NHTSA has decided not to adopt the proposed requirements.
Under the NPRM, those proposed prohibitions would have applied even
if the luggage rack does not enter the survival space, or the seat
anchorages dislodged within the survival space. NHTSA has decided that
the primary purpose of this rulemaking is to establish a roof strength
and crush resistance standard that improves the resistance of roofs to
deformation and intrusion, i.e., by providing a survival

[[Page 74291]]

space to occupants in rollovers. The purpose is achieved by prohibiting
any structure, such as overhead luggage racks, from intruding into the
survival space. By prohibiting overhead luggage racks from impeding
into the survival space in the rollover, overhead luggage racks will
have to be better anchored to the bus wall than they had been in the
past so that they do not detach and intrude into the survival space in
the test. Thus, the proposed luggage rack provision is not needed to
provide a survival space, since luggage racks are prohibited from
intruding into the survival space. By being securely anchored so that
they do not fall into the survival space, luggage racks will be less
likely to impede egress in an emergency, or fall and cause head and
neck injuries to occupants.
NHTSA has decided against adopting the NPRM's proposal that seat
anchorages must not become dislodged during the test. The agency
believes the seat anchorage provision is not necessary to achieve a
survival space for occupants. NHTSA proposed the requirement for the
retention of seat anchorages because of the agency's test of the MY
1991 Prevost LeMirage bus.\87\ In the test, all seats on the opposite
side of the impact detached from their sidewall mounting. A seat with a
restrained mid-size adult male dummy completely separated from its
anchorages and fell across the bus with the restrained dummy attached
to the seat. NHTSA believed at the NPRM stage that the failure of the
seat anchorages during the rollover test presented a significant safety
risk to restrained occupants in bus rollover events and reduced the
effectiveness of seat belts.
---------------------------------------------------------------------------

\87\ A summary of the test may be found in the NPRM, supra, in
section IV.b 79 FR 46100-46102.
---------------------------------------------------------------------------

However, after considering the comments and other information,
NHTSA concludes a requirement that the seat anchorages remain
completely attached is unnecessary. In NHTSA's test of the MY 2000 MCI
bus Model 102-EL3, all of the seats remained attached to their original
anchorages. The seats were ballasted with either a 150 lb
anthropomorphic ballast or with 150 lb steel weights, which is to say
the seats remained attached even while tested under highly demanding
conditions. This test of the MY 2000 MCI bus demonstrates that bus seat
designs have improved since the MY 1991 and 1992 buses NHTSA tested in
its test program.
Second, NHTSA believes the seat anchorage designs are likely to
have improved even more since the design of the MY 2000 bus because of
the agency's 2013 final rule requiring lap/shoulder belts on all large
buses. The final rule requires the lap/shoulder belts to be integral to
the bus seats, and that the belt anchorage, together with the seat
anchorage, meet the rigorous strength requirements of FMVSS No. 210,
``Seat belt assembly anchorages'' 49 CFR 571.210. FMVSS No. 210
requires seat anchorages, attachment hardware, and attachment bolts to
withstand loads of 13,345 N (3,000 lb) applied simultaneously to the
lap belt portion and the shoulder belt portion of the Type 2 restraint
system. Thus, the seat anchorages of new large buses meeting FMVSS No.
210 will be reinforced over and beyond the design of a MY 2000 bus,
which reduces the likelihood even further that the seats will detach
from the bus structure in a rollover as observed in the tests of the MY
1991 and 1992 buses. Thus, the proposed seat anchorage provision is not
necessary to achieve a survival space for occupants.

d. Emergency Exits

The NPRM proposed that emergency exits must remain shut during the
rollover test. The agency was concerned about emergency exits opening
during a rollover, as NHTSA had observed this to happen in the tests
conducted prior to the NPRM. The NPRM also proposed that roof and rear
door emergency exits must be operable in the manner required under
FMVSS No. 217, ``Bus emergency exits and window retention and
release,'' after the test.
Comments Received \88\
---------------------------------------------------------------------------

\88\ ABA requested an exclusion of entertainer buses from
requirements in FMVSS No. 217, S5.2, ``Provision of emergency
exits.'' The request is beyond the scope of the rulemaking and is
not addressed in this preamble.
---------------------------------------------------------------------------

EvoBus commented that the proposal that roof exits remain closed is
unnecessary, as it did not know that any passenger has been ejected
through the roof exit. TEMSA requested that NHTSA move the requirement
that side emergency exits remain closed to proposed FMVSS No. 217a.
NTSB requested that side emergency exit doors also be required to meet
FMVSS No. 227. Advocates suggested the requirement should apply to all
side exits.
Agency Response
In response to EvoBus, NHTSA has observed roof exits opening in the
FMVSS No. 227 tests conducted in support of the NPRM. Their opening
posed an ejection safety risk that this final rule now addresses. Crash
data do not identify the portals through which occupants were ejected,
so data records'' not indicating ejections through roof exits does not
mean such ejections did not or will not occur. The final rule adopts a
simple requirement that will reduce an ejection risk from open portals
in the chaotic and unpredictable phases of a rollover. The cost of
improved emergency latches is minor--$10 per coach for a total annual
new bus fleet cost of $22,000. Congress, in enacting MAP-21, also
wanted NHTSA to address the ejection risk from portals, and an opening
in the bus roof caused by an open emergency exit poses an unreasonable
risk of ejection of a child's head, limb or body, or those of an adult,
in a rollover. NHTSA does not understand why design changes to the roof
exits to enable them to meet the FMVSS No. 227 requirements would
``cause opening failures,'' nor did EvoBus explain its statement.
NHTSA does not agree with TEMSA that the requirements should be
moved to FMVSS No. 217 or to the proposed FMVSS No. 217a. Both 217 and
the proposed 217a do not address the dynamic torsional loads a bus
structure transmits to the emergency exits during the rollover test in
the manner FMVSS No. 227 does. Potential actuation of emergency exit
latches due to inertial loading, assessed by FMVSS No. 227, is not
assessed under current FMVSS No. 217 or proposed Standard No. 217a.
NTSB requests that FMVSS No. 227's requirements should also apply
to side emergency exit doors.\89\ NHTSA agrees, and had proposed that
``emergency exits [should] remain latched to avoid becoming an ejection
portal for unrestrained occupants,'' \90\ and that ``all emergency
exits shall not open during the rollover structural integrity test.''
\91\ The final rule adopts the proposal. However, NHTSA has decided not
to require side emergency doors and emergency windows be operable after
the crash test. The proposed provision that the exits must be operable
after the test goes beyond purposes of the rulemaking (to provide a
safe survival space and to reduce the risk of ejection through
portals).
---------------------------------------------------------------------------

\89\ Under FMVSS No. 217, emergency exit ``windows'' and
emergency exit ``doors'' are considered ``emergency exits,'' whereas
an emergency exit door is a specialized type of emergency exit.
I.e., not all emergency exits are emergency exit ``doors.''
\90\ 79 FR 46109-46110.
\91\ 79 FR 46110.
---------------------------------------------------------------------------

Further, there are challenges to requiring exits on the non-struck
side to open with the bus on its side after the test.\92\ FMVSS No. 217
specifies force

[[Page 74292]]

requirements needed to open the exit, calculated assuming the bus is
upright on its wheels. FMVSS No. 217 only tests the subject buses when
they are upright, so there are no gravity considerations. If the bus
were tested on its side, the force requirement would have to be
calculated to a yet-undetermined level to account for the mass of the
window, the effect of gravity, and the fact that an occupant would be
pushing on the exit while perched on seats they climbed on. NHTSA does
not agree with Advocates that NHTSA should conduct an FMVSS No. 217
test after ``righting'' the bus on its wheels (buses are tested upright
per FMVSS No. 217). The agency is concerned that righting the bus after
the severe rollover test of FMVSS No. 227 may not be possible without
further damaging the structural integrity of the bus. Further,
conducting the test from inside the vehicle as per the FMVSS No. 217
test procedure would expose lab technicians to unreasonable safety
risks.
---------------------------------------------------------------------------

\92\ This issue was discussed in the NPRM (79 FR 46110).
---------------------------------------------------------------------------

XI. Glazing Issues

a. Side Glazing on the Non-Struck Side of the Bus

The NPRM proposed that each side window glazing on the non-struck
side of the vehicle would have to remain attached to its mounting such
that there is no opening that will allow the passage of a 102 mm (4
inch) diameter sphere when a force of no more than 22 N is applied.
This final rule does not adopt this provision. The sphere test was
proposed to ensure that, after the rollover test, the glazing remain
securely attached to its mounting. Because the primary purpose of this
rulemaking is to provide a necessary survival space to occupants in
rollovers, the purpose is achieved by prohibiting harmful panes of
glazing from intruding into the survival space. The proposed
requirement that the glazing remain securely attached to its mounting
is redundant to the survival space specification and unnecessarily
complicates this rulemaking.\93\
---------------------------------------------------------------------------

\93\ Some commenters objecting to the sphere test misunderstood
the purpose of the test. The test was not intended to simulate an
unbelted passenger's impact onto bus window glazing during a bus
rollover. The sphere test was intended simply to measure whether the
bus structure retained the glazing panels in the window frame when
subjected to a rollover. In the final rule, this would be assessed
by the prohibition that no large object enter the survival space.
While retention of the glazing in its mounting could reduce occupant
ejection, whether the glazing forms an opening through which an
ejection could occur in a rollover crash, is the subject of NHTSA's
proposed FMVSS No. 217a and will be addressed in the context of that
rulemaking. 81 FR 27904, May 6, 2016, supra.
---------------------------------------------------------------------------

b. Type of Glazing

EPGAA, Greyhound and Advocates requested that the agency require
advanced glazing material in bus windows, while Prevost, Van Hool, and
EvoBus suggest that tempered glass should be permitted. Prevost
expresses that ``there is a small possibility that some glazing could
shatter when submitted to the proposed testing.'' Prevost and EvoBus
request an exclusion of tempered glazing from the rule, or that
shattered glazing not be considered a failure of the FMVSS No. 227
requirements.
Agency Response
The agency is not distinguishing among glazing types in FMVSS No.
227 or providing exclusions of tempered glazing. The standard is
generally performance-oriented and technology neutral, requiring window
glazing and surrounding window frame structures on the non-struck sides
of the bus to be manufactured so as not to unsafely intrude into the
survival space in the rollover test. As discussed above, this final
rule accommodates intrusion of small pebbles of tempered glass into the
survival space. This final rule makes allowances for minute objects
weighing less than 15.0 grams to enter the survival space, in
recognition that it may be difficult, and unnecessary, to keep more
miniscule pieces of glazing and other items from entering the survival
space in the FMVSS No. 227 rollover event.
The requirement in FMVSS No. 227 preventing bus components from
intruding into the survival space is critical to rollover safety if the
subject buses employ advanced glazing that mitigate the risk of
occupant ejection in rollovers. NHTSA's research \94\ found that
advanced glazing, such as laminated glazing, could pop out of its
mounting due to torsional deformation of the structure around the
window. FMVSS No. 227's survival space requirement would improve the
structural integrity around window frames and prevent glazing from
popping out or otherwise detaching from its window mount in a rollover.
---------------------------------------------------------------------------

\94\ Martec Limited, ``Motorcoach Glazing Retention Test
Development For Occupant Impact During a Rollover,'' August 2006;
Docket No. NHTSA-2002-11876-0015.
---------------------------------------------------------------------------

c. Moon Roofs

NTSB requested NHTSA consider including ``moon roofs'' in the
glazing retention requirements of FMVSS No. 227. We agree with NTSB
that ``moon roofs'' should be subject to the requirements of FMVSS No.
227, as there is a risk of passenger ejection through glass roofs
during a bus rollover. Rather than use the term ``moon roofs'' however,
hereinafter we use the term ``roof panel/windows'' since the latter
term is more descriptive and inclusive of the components we seek to
address.
Ejections through the roof occur in real-world crashes. From 2000-
2009, two-thirds of the rollover fatalities in the subject buses were
ejected occupants.\95\ Two of the crashes (Turrell, Arkansas in 2004
and Mexican Hat, Utah in 2008) discussed in the NPRM involved roof
separation from the bus. Almost all the passengers in those two crashes
were ejected due to the loss of the bus roofs. In such crash events,
unrestrained passengers can still be ejected if a bus that meets the
survival space requirements fails to keep roof panels/windows closed or
intact. We believe that manufacturers can use the same countermeasures
to retain roof panels/windows to the glazing frames that they use to
keep side window glazing attached to the side window frames.
---------------------------------------------------------------------------

\95\ 79 FR 46098; August 6, 2014.
---------------------------------------------------------------------------

MAP-21 \96\ defines a 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.'' Roof
panels/windows are portals per the MAP-21 definition. Any bus opening
containing glazing material is a portal that can become an opening
through which bus occupants may be partially or completely ejected if
the glazing detaches from its mounting. The final rule's including roof
panels/windows in FMVSS No. 227 accords with MAP-21. We will evaluate
roof panels/windows like we do side windows. I.e., no portion of a roof
panel/window may enter the survival space, except for objects weighing
less than 15.0 grams, and they must remain closed.
---------------------------------------------------------------------------

\96\ See Sec. 32072, supra.
---------------------------------------------------------------------------

d. Struck-Side Window Evaluations

Several commenters (Advocates, Greyhound, NTSB, the families, and
Ms. Stoos) request that the agency evaluate windows on the struck side
as well as the non-struck side of the bus.
Under FMVSS No. 227, the agency can roll either side of the bus.
Thus, manufacturers must ensure that vehicles can resist the torsional
loads imparted into the structure on either side of the bus. To the
extent the commenters suggest the sphere test should be conducted on
the struck-side windows

[[Page 74293]]

when the bus is resting on the ground, as discussed above the agency is
not adopting the sphere test, or any test involving lab technicians
entering the rolled vehicle to assess compliance with a requirement.

XII. Test Procedure Issues

a. Ballasting the Vehicle

To simulate a real-world rollover incorporating foreseeable
conditions that are challenging to the vehicle, NHTSA proposed to
subject the vehicle to the forces resulting from the mass of restrained
occupants. To achieve this, the NPRM proposed (in S6.2.5 of the
regulatory text) that a mass up to 68 kg (150 lb) (ballast) be secured
in each designated seating position (DSP) equipped with a seat
belt.\97\ The ballast would represent the mass of an ``average''
occupant, and is the mass NHTSA uses in determining a vehicle's GVWR
per 49 CFR part 567, ``Certification.'' NHTSA stated that ballasting is
important because it increases the weight and center of gravity of the
vehicle, which better simulates the forces on the vehicle structure in
a rollover when the seats are occupied by belted passengers. Also, when
occupants are belted into the vehicle, their mass imparts crash forces
to the seat anchorages during a crash, which NHTSA sought to replicate
in the test (79 FR 46105-46107).
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\97\ All DSPs in the buses are required to have seat belts per
our November 25, 2013 MAP-21 final rule amending FMVSS No. 208 (78
FR 70416).
---------------------------------------------------------------------------

The agency indicated in the NPRM that it did not believe the method
of ballasting or type of ballast used were of importance, as those
factors will not significantly alter the forces imposed on the vehicle
structure or the seat anchorages during compliance testing, so long as
the ballast is 68 kg (150 lb) at each DSP. NHTSA noted in the NPRM that
the NPRM differed from ECE R.66 on this issue of ballasting. ECE R.66
specifies the option of two different methods of securing occupant
ballast to the passenger seats.\98\ It reduces the load to 34 kg (75
lb) when a fixed ballast is used (79 FR 46106). Further, it specifies a
different ballasting method.\99\
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\98\ As discussed in the NPRM (79 FR 46107), we tested both
types of ballasts, anthropomorphic (``water dummies'') ballasts and
fixed steel ballasts, to determine the feasibility of each and the
differences between the two. We found that the method of ballasting
and type of ballast used were not important, as these factors did
not significantly alter the forces upon the vehicle structure or the
seat anchorages during the test, so long as the ballast is 68 kg
(150 lb). Four commercially available ``water dummies,'' each filled
with 68 kg (150 lb) of sand, were installed in one full row of seats
(four seating positions) and were secured with ratchet straps that
were configured to simulate Type 2 seat belts. Steel ballasts, 68 kg
(150 lb) per seating position, were installed in a second full row
of seats (four seats). In this row, steel plates were placed on top
of each seat cushion and were secured with bolts that passed through
the cushion and attached to a bar which clamped onto the seat frame.
The overall center of gravity of the bus, and consequently, the
energy absorbed in the test, was only slightly higher (less than 3
percent) when the water dummies were used compared to when the fixed
weights were used. The differences in forces and moments generated
at the anchorages due to the ballasts were also small.
\99\ In addition to specifying a different weight for fixed
steel plate ballasts, ECE R.66 requires the ballasts be fixed to the
seat such that its center of gravity aligns with that of the
anthropomorphic ballast (i.e. , approximately 100 mm forward and 100
mm above the seating reference point). However, NHTSA simply
proposed to fix the steel ballasts to the seat because in the
agency's research NHTSA found it difficult to position and fix the
rigid weights per the ECE specification. We investigated whether
affixing the rigid weights as specified by ECE R.66 is necessary and
stated in the NPRM that it was not. The different center of gravity
heights between the anthropomorphic ballasts and the fixed weight
ballasts did not appear to affect the overall performance of the
vehicle in the rollover test. 79 FR 46107.
---------------------------------------------------------------------------

Comments Received
Several bus manufacturers commented on the proposal, all requesting
that we adopt the ballasting approach of ECE R.66 (i.e. , the
anthropomorphic ballast at 68 kg (150 lb) and the fixed steel plate
ballast at 34 kg (75 lb)).\100\ All the commenters essentially argue
that passengers in a bus, restrained by the seat belts, will not
transfer their entire load onto the seat anchorages and bus structure
in the same way as fixed ballasts. Therefore, commenters argue, when
using the fixed steel plate ballasts, the ballast weight should be 34
kg (75 lb) (i.e. , 50 percent of the weight for anthropomorphic
ballasts).
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\100\ Greyhound Lines, Inc., an operator, suggested that NHTSA
should ballast the overhead luggage racks during rollover testing.
Ballasting of luggage rack and the lower luggage compartment of a
motorcoach was not proposed in the August 6, 2014 NPRM and therefore
the public was not provided a full opportunity to comment on this
issue. ECE R.66 does not require ballasting of the luggage rack, and
NHTSA does not see a safety need for a requirement to ballast the
luggage racks.
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In support of their view that a 50 percent weight is appropriate
for fixed ballasts, the commenters argue that ECE R.66 considers a 75-
lb weight for fixed steel ballasts equivalent to the 150-lb
anthropomorphic ballast secured with the seat belt. Van Hool cites an
ECE Ad Hoc Expert Group document that puts the load transferred by
belted occupants to the vehicle structure as between 0 and 100 percent
of the standard passenger mass of 68 kg (150 lb).\101\ Prevost and
Daimler both cite an ECE analysis finding that 50 percent of the
restrained occupant's weight transfers to the bus structure during a
crash.\102\
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\101\ See Report about the Ad-Hoc Expert Group (AHEG) meeting
dealing with the development of Regulation 66 (Frankfurt, 22-23,
November, 2001), available at <a href="https://www.unece.org/fileadmin/DAM/trans/doc/2002/wp29grsg/TRANS-WP29-GRSG-82-inf02.doc">https://www.unece.org/fileadmin/DAM/trans/doc/2002/wp29grsg/TRANS-WP29-GRSG-82-inf02.doc</a> (last accessed
February 8, 2017).
\102\ Study about the Incidence of the Use of Safety Belts with
regard to Regulation 66 of Geneva, presented by Spain at the 81th
Working Party on General Safety Provisions (GRSG), October, 2001,
<a href="https://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29grsg/grsginf/81/grsg81_inf09.doc">https://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29grsg/grsginf/81/grsg81_inf09.doc</a> (last accessed February 8,
2017).
---------------------------------------------------------------------------

Agency Response
NHTSA is adopting the provision to use the 68 kg (150 lb) ballast
in NHTSA's compliance test. NHTSA does not concur that a 75-lb (50
percent lighter weight) fixed ballast would simulate a similar amount
of force on the seat anchorages and bus structure as a 150-lb occupant.
Prevost's and Daimler's comments reflect the state of knowledge in
2001, a time early in the development of ECE R.66. According to their
cited analysis, there were no experimental data available at the time
to evaluate the percentage of mass that should be included in the test.
At that time, it was then theorized that 50 percent of the occupant
weight was an appropriate estimate for the weight that a restrained
occupant would transfer to the bus structure. However, subsequent
published studies have found that the 50 percent value grossly
underestimates the amount of force imparted by restrained bus
occupants.
As discussed in the NPRM (79 FR 46106), an Australian study that
utilized bus section testing and computer simulations \103\ estimated
that 93 percent of a lap/shoulder belt-restrained occupant mass, 75
percent of a lap belt-restrained occupant mass, and 18 percent of an
unrestrained occupant mass are effectively coupled to the vehicle
structure during a rollover. Further, a European Commission sponsored
study in 2003 \104\ found that the percentage of occupant mass coupled
to the vehicle structure during a rollover is 90 percent for lap/
shoulder belted occupants and 70 percent for lap belted occupants.
Based on these research findings, NHTSA proposed in the NPRM to use the
full weight of 150 lb (68 kg) at all DSPs.
---------------------------------------------------------------------------

\103\ Anderson, J., et al., ``Influence of Passengers During
Coach Rollover,'' Cranfield Impact Centre Ltd., 18th International
Technical Conference on the Enhanced Safety of Vehicles, Nagoya,
Japan, Paper No. 216, 2003.
\104\ Enhanced Coach and Bus Occupant Safety (ECBOS), Project
No. 1999-RD.11130, European Commission, 5th Framework, August 2003.
---------------------------------------------------------------------------

Since the NPRM, NHTSA has learned about additional studies that
corroborate the Australian and ECE findings. An

[[Page 74294]]

Italian study \105\ reports that seat deformation is influenced by an
occupant's weight during rollover testing. Reports co-authored by TEMSA
<SUP>106</SUP> <SUP>107</SUP> conclude that 90 percent of the
passengers' mass should be added to the rollover vehicle mass. Thus,
the data cited by Prevost and Daimler appear to be outdated. Available
studies now uniformly agree that more than 90 percent of the occupant
mass is coupled with the bus during a rollover crash. Accordingly, we
disagree with ballasting only 50 percent of the 150-lb occupant load.
---------------------------------------------------------------------------

\105\ Belingardi, G., Martella, P., and Peroni, L., ``Coach
Passenger Injury Risk During Rollover: Influence of the Seat and the
Restraint System,'' 19th International Technical Conference on the
Enhanced Safety of Vehicles, Washington DC, Paper No. 05-0439, 2005.
\106\ Guler, M., Atahan, A., and Bayram, B, ``Effectiveness of
Seat Belt Usage on the Rollover Crashworthiness of an Intercity
Coach''; 21st International Technical Conference on the Enhanced
Safety of Vehicles, Stuttgart, Germany, Paper No. 09-0205, 2009.
\107\ Elitok, K., Guler, M., Bertan Bayram, B., and Stelzmann,
U., ``An Investigation on the Roll-Over Crashworthiness of an
Intercity Coach, Influence of Seat Structure and Passenger Weight,''
9th International LS-DYNA Users Conference, 2006.
---------------------------------------------------------------------------

For the above reasons, we are adopting the proposed language from
the NPRM on ballasting. Using lower weight ballast for the fixed
ballast, as suggested by some commenters, would not adequately simulate
the loading conditions of the average restrained occupant.\108\
---------------------------------------------------------------------------

\108\ NHTSA asked for comment on whether, when fixed ballasts
are used, it is necessary to specify a specific center of gravity
for the fixed steel plate ballasts. 79 FR 46107. No comments were
received on this issue. For the reasons in the NPRM, NHTSA believes
it is sufficient for the steel ballasts to be placed on top of the
seat cushion.
---------------------------------------------------------------------------

b. Vehicle Fluids

NHTSA specified that all fluids in the vehicle, including fuel,
would be at maximum capacity during the test. For environmental and
test personnel safety, NHTSA proposed to use substitute fluids to
conduct the test if the weight of the original fluid was maintained.
Comments Received
Van Hool commented that NHTSA should not include vehicle fluid
specifications and should permit manufacturers to replace parts of the
bus representative masses. The commenter believed that manufacturers
should be able to decide on these conditions and determine them for
their bus if ``the basic features and behaviour [sic] of the
superstructure are not influenced by it.'' Van Hool recommends that the
agency use the ECE R.66 definition of cg to determine whether the
manufacturer's selected vehicle conditions are appropriate for testing.
Agency Response
We have changed the regulatory text so that vehicle fluid fill
levels are now specified as a percentage range of the maximum capacity
rather than only as maximum capacity. FMVSS No. 227 specifies that the
agency will test the bus with all fluids (or replacement fluids) at 90
to 95 percent of the maximum level for each of the fluids.
In specific response to Van Hool, NHTSA does not believe the
requested change is necessary. Van Hool requested that NHTSA use
manufacturer-defined test conditions for items such as the vehicle
fluid levels and representative masses for expensive vehicle parts, if
the manufacturer-specified conditions maintain a specified cg. As NHTSA
explained in the NPRM, in the U.S., manufacturers self-certify their
products'' compliance with the FMVSSs. The test conditions specified in
an FMVSS specify the conditions under which NHTSA will assess
compliance. The purpose of specifying these conditions is to give
manufacturers notice of how NHTSA will test, not to prescribe the
testing methods that manufacturers must use to certify compliance.
To illustrate, FMVSS No. 227 specifies that the agency will test
the bus with all fluids (or replacement fluids) at 90 to 95 percent of
the maximum level for each of the fluids. The standard does not require
manufacturers to conduct the test under the same conditions.
Manufacturers may use different testing methods to certify compliance
with the FMVSSs. They must reasonably conclude that their vehicles will
pass the FMVSS test when tested by NHTSA as specified in the FMVSS. It
is not incumbent on NHTSA to specify in the FMVSSs all the possible
testing methods a manufacturer might use as a basis for its
certification.

c. Additional Tools for Survival Space Evaluation During Testing

Van Hool suggested that additional evaluation tools be permitted as
supplemental or alternatives to the proposed survival space template,
to simplify testing. It stated that high-speed photography, video,
deformable templates, electrical contact sensors, and other suitable
evaluation and techniques should be permitted as part of the standard.
After considering the comment, NHTSA has decided to change some of
the language in the regulatory text of FMVSS No. 227 to provide more
flexibility in the tools the agency will use to measure compliance. As
stated in the NPRM, we intended that ``[o]ther tools could also be used
to help determine whether there was intrusion into the survival space,
such as deformable templates, high speed video, photography, or a
combination of means. NHTSA could use templates and/or other means of
determining whether intrusion occurred.'' \109\ However, describing the
use of survival space templates in detail in the regulatory text of
FMVSS No. 227 implies the opposite, and makes unclear NHTSA's
flexibility to use other compliance tools that are not described in the
regulatory text. We believe it would be more efficient for the agency
to move the specifications on the detailed use of templates or other
methods to a test procedure document that NHTSA's Office of Vehicle
Safety Compliance publishes.
---------------------------------------------------------------------------

\109\ 79 FR 46109.
---------------------------------------------------------------------------

XIII. Other Issues

a. ECE R.66 Alternative Compliance Methods

The rollover test in this final rule is based on the complete
vehicle test from ECE R.66. NHTSA is not adopting ECE R.66's four
alternative options for complying with ECE R.66 requirements.\110\ The
following options are considered by ECE R.66 to be equivalent approval
tests: (1) A rollover structural integrity test of body sections
representative of the vehicle, (2) quasi-static loading tests of body
sections, (3) quasi-static calculations based on testing of components,
and (4) computer simulation (finite element analysis) of a complete
vehicle.\111\
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\110\ There are significant differences in the way a
manufacturer demonstrates compliance with safety regulations in
European Union and in the United States. In Europe, European
governments use ``type approval,'' which means that they approve
particular designs as complying with their safety standards. In the
U.S., NHTSA issues performance standards, to which manufacturers
self-certify that their vehicles or equipment comply. NHTSA does not
pre-approve vehicles or equipment before sale. Under the Vehicle
Safety Act, the FMVSSs must be objective, repeatable, and meet
certain other statutory criteria. NHTSA enforces the FMVSSs by
obtaining new vehicles and equipment for sale and testing them to
the requirements in the FMVSSs according to the procedures specified
in the standards.
\111\ Further information regarding the alternative
certification methods of ECE R.66 is available at: Motorcoach Roof
Crush/Rollover Testing Discussion Paper, March 2009, Docket No.
NHTSA-2007-28793-0019.
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Comments Received
Bus manufacturers already producing vehicles subject to ECE R.66
(Van Hool, TEMSA, Prevost, EvoBus) asked NHTSA to adopt the
alternatives of ECE R.66. TEMSA believed that computer

[[Page 74295]]

simulation would be feasible if NHTSA ``defines the performance
requirements, assumptions, calculations and validation method in the
regulation, [and] all manufacturers make the same assumptions and
perform the test with same simulation and analysis methods.'' Prevost
believed that ECE R.66 alternatives may be used to prove certification
of designs that are ``evolutions of what already exists.'' EvoBus
believed not allowing numerical simulation imposes a burden because
``it would be necessary to provide a vehicle with exactly the same
specifications as the one which gave raise to questions.''
Agency Response
This final rule adopts the complete vehicle test of ECE R.66 into
FMVSS No. 227. By doing so, NHTSA is specifying the test procedure
NHTSA will use to assess a vehicle's compliance with FMVSS No. 227. The
standard will not provide for NHTSA's use of Alternatives 1 through 4
to determine compliance. However, this does not mean that manufacturers
must use the complete vehicle test to certify their vehicles. To the
contrary, the Safety Act requires manufacturers to ensure their vehicle
meet all applicable FMVSSs, and that they certify the compliance of
their vehicle with applicable FMVSS. The Safety Act specifies that
manufacturers may not certify if in exercising reasonable care the
manufacturer has reason to know the certificate is false or misleading.
This means a manufacturer may use the alternative compliance methods of
ECE R.66 to certify its vehicles if it can do so in exercising
reasonable care. While manufacturers must ensure that their vehicles
will meet the requirements of FMVSS No. 227 when NHTSA tests the
vehicles in accordance with the test procedures specified in the
standard, they do not have to conduct the test described in FMVSS No.
227 to certify that compliance.
NHTSA considered ECE R.66's alternative compliance methods but
determined that they would not be practical for the agency's compliance
program. (See explanation in the NPRM, 79 FR 46111-46112.) The agency
has considered the comments but has not changed its mind.
Alternatives 1 and 2 involve testing body sections. To obtain a
body section, NHTSA could procure

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