[Federal Register Volume 86, Number 247 (Wednesday, December 29, 2021)]
[Rules and Regulations]
[Pages 74270-74307]
[FR Doc No: 2021-27538]

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

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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 https://www.regulations.gov,
including any personal information provided.
    Privacy Act: Please see the Privacy Act heading under Rulemaking
Analyses and Notices.

FOR FURTHER INFORMATION CONTACT: For non-legal issues, you may contact
James Myers, NHTSA Office of Crashworthiness Standards, telephone 202-
493-0031, fax<PHONE_NUMBER>. For legal issues: Deirdre Fujita, NHTSA
Office of Chief Counsel, telephone<PHONE_NUMBER>, fax<PHONE_NUMBER>.
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, https://www.fmcsa.dot.gov/sites/fmcsa.dot.gov/files/docs/Motorcoach-Safety-Action-Plan-2012.pdf. 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

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, https://live.unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/r066r1e.pdf. 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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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; https://www.ntsb.gov/investigations/AccidentReports/Reports/HAR0902.pdf,
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

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]
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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]
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------------------------------------------------------------------------
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]
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------------------------------------------------------------------------
15 percent belt usage................................          2.48-4.99
90 percent belt usage................................          3.17-6.38
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                                      Table 4--Annualized Costs and Benefits
                                          [In millions of 2020 dollars]
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                                                            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
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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

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\
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    \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: https://www-esv.nhtsa.dot.gov/Proceedings/20/07-0152-O.pdf, 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: https://www-esv.nhtsa.dot.gov/Proceedings/20/07-0152-O.pdf, 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

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

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 https://unece.org/DAM/trans/doc/2012/wp29grsg/GRSG-103-02e.pdf. 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

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

    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. https://www-nrd.nhtsa.dot.gov/database/aspx/searchmedia2.aspx?database=v_=6797&mediatype=r&r_;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

[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

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

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

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.

                                  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 https://www.transit.dot.gov/sites/fta.dot.gov/files/docs/AnEvaluationofMarketforSmalltoMediumSizedCutawayBuses.pdf, 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

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.''
---------------------------------------------------------------------------

    \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\
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    \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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    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.
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    \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)).
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    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.
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    \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.

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, http://us.megabus.com/, 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\ https://www.unece.org/fileadmin/DAM/trans/doc/2008/wp29grsg/GRSG-95-07e.pdf (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--
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    \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 https://www.abc-companies.com/ 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