permit buses meeting FMVSS No. 221 the option of meeting FMVSS No. 220
rather than FMVSS No. 227. They state that the buses are similar in
appearance to school buses but are sold for non-school related
purposes. The commenters contend that the operating environment for
these buses is closer to that of school buses than intercity buses and
that the vehicles should be subject to the school bus safety standards
for rollover protection (FMVSS No. 220) and joint strength (FMVSS No.
221) rather than FMVSS No. 227.
---------------------------------------------------------------------------

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

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

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

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

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

X. Performance Requirements

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

a. Severity of the Rollover Test

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

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

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

    \68\ Available at: https://www-esv.nhtsa.dot.gov/Proceedings/20/07-0152-O.pdf.
---------------------------------------------------------------------------

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

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

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

[GRAPHIC] [TIFF OMITTED] TR29DE21.002

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

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

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

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

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

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

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

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

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

    Advocates also discuss a crash variation where the bus may hit an
embankment or other ``vertical surface'' type object. This crash
variation may or may not increase the total energy to be dissipated
during the crash, but the load concentration may change. However, even
with different potential objects loading the structure, we believe that
the loads to which the superstructure is subjected might be similar in
some respects to the loading to which the superstructure is exposed
when tested under FMVSS No. 227. While no embankment or other
``vertical surface''-type object is a part of the test, the vehicle
superstructure's loading during the test is akin to the concentrated
force that is applied when striking a ``vertical surface.'' The test
involves loading the entirety of the energy in the test onto a
concentrated section of the structure (i.e. , the corner of the roof).
Thus, we believe that FMVSS No. 227 reflects an aspect of the
``vertical surface'' and other crash variations about which Advocates
is concerned.\76\
---------------------------------------------------------------------------

    \76\ NHTSA also notes that, at this time, the petitioner's
request to incorporate vertical surfaces to mimic a motorcoach
accident scenario is impractical to meet. To adopt an objective,
repeatable and meaningful test maneuver that incorporates highway
speeds and vertical surfaces for the bus to impact, NHTSA should
have additional information on what speed is representative, how to
trip the bus to initiate a roll, what vertical surface objects are
representative, etc. Such information is now unavailable. Further, a
test incorporating highway speeds and vertical surfaces is currently
not practical as the test conditions are exceedingly difficult to
replicate, and pose inordinate safety risks to technicians
conducting the test.
---------------------------------------------------------------------------

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

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

b. Intrusion Into the Survival Space

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

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

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

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

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

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

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

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

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

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

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

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

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

C. Luggage Racks and Seat Anchorages

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

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

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

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

d. Emergency Exits

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

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

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

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

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

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

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

XI. Glazing Issues

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

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

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

b. Type of Glazing

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

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

c. Moon Roofs

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

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

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

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

d. Struck-Side Window Evaluations

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

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

XII. Test Procedure Issues

a. Ballasting the Vehicle

    To simulate a real-world rollover incorporating foreseeable
conditions that are challenging to the vehicle, NHTSA proposed to
subject the vehicle to the forces resulting from the mass of restrained
occupants. To achieve this, the NPRM proposed (in S6.2.5 of the
regulatory text) that a mass up to 68 kg (150 lb) (ballast) be secured
in each designated seating position (DSP) equipped with a seat
belt.\97\ The ballast would represent the mass of an ``average''
occupant, and is the mass NHTSA uses in determining a vehicle's GVWR
per 49 CFR part 567, ``Certification.'' NHTSA stated that ballasting is
important because it increases the weight and center of gravity of the
vehicle, which better simulates the forces on the vehicle structure in
a rollover when the seats are occupied by belted passengers. Also, when
occupants are belted into the vehicle, their mass imparts crash forces
to the seat anchorages during a crash, which NHTSA sought to replicate
in the test (79 FR 46105-46107).
---------------------------------------------------------------------------

    \97\ All DSPs in the buses are required to have seat belts per
our November 25, 2013 MAP-21 final rule amending FMVSS No. 208 (78
FR 70416).
---------------------------------------------------------------------------

    The agency indicated in the NPRM that it did not believe the method
of ballasting or type of ballast used were of importance, as those
factors will not significantly alter the forces imposed on the vehicle
structure or the seat anchorages during compliance testing, so long as
the ballast is 68 kg (150 lb) at each DSP. NHTSA noted in the NPRM that
the NPRM differed from ECE R.66 on this issue of ballasting. ECE R.66
specifies the option of two different methods of securing occupant
ballast to the passenger seats.\98\ It reduces the load to 34 kg (75
lb) when a fixed ballast is used (79 FR 46106). Further, it specifies a
different ballasting method.\99\
---------------------------------------------------------------------------

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

Comments Received
    Several bus manufacturers commented on the proposal, all requesting
that we adopt the ballasting approach of ECE R.66 (i.e. , the
anthropomorphic ballast at 68 kg (150 lb) and the fixed steel plate
ballast at 34 kg (75 lb)).\100\ All the commenters essentially argue
that passengers in a bus, restrained by the seat belts, will not
transfer their entire load onto the seat anchorages and bus structure
in the same way as fixed ballasts. Therefore, commenters argue, when
using the fixed steel plate ballasts, the ballast weight should be 34
kg (75 lb) (i.e. , 50 percent of the weight for anthropomorphic
ballasts).
---------------------------------------------------------------------------

    \100\ Greyhound Lines, Inc., an operator, suggested that NHTSA
should ballast the overhead luggage racks during rollover testing.
Ballasting of luggage rack and the lower luggage compartment of a
motorcoach was not proposed in the August 6, 2014 NPRM and therefore
the public was not provided a full opportunity to comment on this
issue. ECE R.66 does not require ballasting of the luggage rack, and
NHTSA does not see a safety need for a requirement to ballast the
luggage racks.
---------------------------------------------------------------------------

    In support of their view that a 50 percent weight is appropriate
for fixed ballasts, the commenters argue that ECE R.66 considers a 75-
lb weight for fixed steel ballasts equivalent to the 150-lb
anthropomorphic ballast secured with the seat belt. Van Hool cites an
ECE Ad Hoc Expert Group document that puts the load transferred by
belted occupants to the vehicle structure as between 0 and 100 percent
of the standard passenger mass of 68 kg (150 lb).\101\ Prevost and
Daimler both cite an ECE analysis finding that 50 percent of the
restrained occupant's weight transfers to the bus structure during a
crash.\102\
---------------------------------------------------------------------------

    \101\ See Report about the Ad-Hoc Expert Group (AHEG) meeting
dealing with the development of Regulation 66 (Frankfurt, 22-23,
November, 2001), available at https://www.unece.org/fileadmin/DAM/trans/doc/2002/wp29grsg/TRANS-WP29-GRSG-82-inf02.doc (last accessed
February 8, 2017).
    \102\ Study about the Incidence of the Use of Safety Belts with
regard to Regulation 66 of Geneva, presented by Spain at the 81th
Working Party on General Safety Provisions (GRSG), October, 2001,
https://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29grsg/grsginf/81/grsg81_inf09.doc (last accessed February 8,
2017).
---------------------------------------------------------------------------

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

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

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

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

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

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

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

b. Vehicle Fluids

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

c. Additional Tools for Survival Space Evaluation During Testing

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

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

XIII. Other Issues

a. ECE R.66 Alternative Compliance Methods

    The rollover test in this final rule is based on the complete
vehicle test from ECE R.66. NHTSA is not adopting ECE R.66's four
alternative options for complying with ECE R.66 requirements.\110\ The
following options are considered by ECE R.66 to be equivalent approval
tests: (1) A rollover structural integrity test of body sections
representative of the vehicle, (2) quasi-static loading tests of body
sections, (3) quasi-static calculations based on testing of components,
and (4) computer simulation (finite element analysis) of a complete
vehicle.\111\
---------------------------------------------------------------------------

    \110\ There are significant differences in the way a
manufacturer demonstrates compliance with safety regulations in
European Union and in the United States. In Europe, European
governments use ``type approval,'' which means that they approve
particular designs as complying with their safety standards. In the
U.S., NHTSA issues performance standards, to which manufacturers
self-certify that their vehicles or equipment comply. NHTSA does not
pre-approve vehicles or equipment before sale. Under the Vehicle
Safety Act, the FMVSSs must be objective, repeatable, and meet
certain other statutory criteria. NHTSA enforces the FMVSSs by
obtaining new vehicles and equipment for sale and testing them to
the requirements in the FMVSSs according to the procedures specified
in the standards.
    \111\ Further information regarding the alternative
certification methods of ECE R.66 is available at: Motorcoach Roof
Crush/Rollover Testing Discussion Paper, March 2009, Docket No.
NHTSA-2007-28793-0019.
---------------------------------------------------------------------------

Comments Received
    Bus manufacturers already producing vehicles subject to ECE R.66
(Van Hool, TEMSA, Prevost, EvoBus) asked NHTSA to adopt the
alternatives of ECE R.66. TEMSA believed that computer

simulation would be feasible if NHTSA ``defines the performance
requirements, assumptions, calculations and validation method in the
regulation, [and] all manufacturers make the same assumptions and
perform the test with same simulation and analysis methods.'' Prevost
believed that ECE R.66 alternatives may be used to prove certification
of designs that are ``evolutions of what already exists.'' EvoBus
believed not allowing numerical simulation imposes a burden because
``it would be necessary to provide a vehicle with exactly the same
specifications as the one which gave raise to questions.''
Agency Response
    This final rule adopts the complete vehicle test of ECE R.66 into
FMVSS No. 227. By doing so, NHTSA is specifying the test procedure
NHTSA will use to assess a vehicle's compliance with FMVSS No. 227. The
standard will not provide for NHTSA's use of Alternatives 1 through 4
to determine compliance. However, this does not mean that manufacturers
must use the complete vehicle test to certify their vehicles. To the
contrary, the Safety Act requires manufacturers to ensure their vehicle
meet all applicable FMVSSs, and that they certify the compliance of
their vehicle with applicable FMVSS. The Safety Act specifies that
manufacturers may not certify if in exercising reasonable care the
manufacturer has reason to know the certificate is false or misleading.
This means a manufacturer may use the alternative compliance methods of
ECE R.66 to certify its vehicles if it can do so in exercising
reasonable care. While manufacturers must ensure that their vehicles
will meet the requirements of FMVSS No. 227 when NHTSA tests the
vehicles in accordance with the test procedures specified in the
standard, they do not have to conduct the test described in FMVSS No.
227 to certify that compliance.
    NHTSA considered ECE R.66's alternative compliance methods but
determined that they would not be practical for the agency's compliance
program. (See explanation in the NPRM, 79 FR 46111-46112.) The agency
has considered the comments but has not changed its mind.
    Alternatives 1 and 2 involve testing body sections. To obtain a
body section, NHTSA could procure it from the manufacturer, but that
raises questions about how representative the sample would be of buses
in actual production. Some manufacturers might make a more
conscientious effort to produce the specimen, and so the specimen might
not be representative of a typical mass-produced bus. NHTSA could
section a bus itself, but that would be impractical and a waste of
resources.
    Alternatives 1 and 2 require that the body-sections be
representative of the entire vehicle. Determining the
representativeness of a body-section would require input and analysis
from the manufacturer, and even with that, determining what is
``representative'' could be subjective and difficult for NHTSA to
verify. (E.g., is the center of gravity of the body section
representative of the whole vehicle?) Importantly, it might make more
sense if the representative sample were representative of the worst-
case (weakest) section, to make sure all body sections of the bus are
capable of passing the test. The alternatives do not make it clear that
NHTSA could test the weakest section, and thus do not make clear that
the entire vehicle would have to meet the standard.
    Testing an entire vehicle rather than body sections is preferable
to NHTSA because it better ensures all body sections will be able to
conform to FMVSS No. 227, including representative as well as worse-
case (weakest) sections of the bus. Testing an entire bus to the
complete vehicle test is the most objective, scientific way to assure
the entire bus structure is satisfactory and the glazing panels are
retained.
    Regarding Alternatives 3 and 4, under the Safety Act, NHTSA is
directed to issue performance standards,\112\ the compliance with which
must be measured objectively.\113\ A concern with assessing compliance
using calculations, extrapolations, and computer simulations is that
entities may differ in opinion as to whether a manufacturer's
calculations and computer simulations were appropriate or correctly
made for demonstrating compliance in a particular instance. A
manufacturer may have the knowledge of the materials and joint
structure for their vehicles to be able to accurately model them, while
an external entity may not be able to easily reproduce those results.
---------------------------------------------------------------------------

    \112\ In 49 U.S.C. 30102, the Vehicle Safety Act defines ``motor
vehicle safety'' as the ``performance'' of motor vehicles or motor
vehicle equipment in a way such as to avoid creating an unreasonable
risk of accident to the general public. The same Act defines ``motor
vehicle safety standards'' as minimum standards for motor vehicle or
motor vehicle equipment ``performance.''
    \113\ In 49 U.S.C. 30111(a), the Vehicle Safety Act requires
that Federal motor vehicle safety standards be stated in objective
terms.
---------------------------------------------------------------------------

    The variability of assumptions in such models makes this method
less preferable for use by NHTSA in evaluating compliance with an
FMVSS. For example, for Alternative 3, we would need to identify the
location of the plastic zones and plastic hinges as well as estimate
their load-deformation curves. For Alternative 4, mathematical models
that simulate accurately the actual rollover crash of the vehicle are
required.
    Further, there is a concern that basing compliance on calculations
and computer simulations may not account for differences that may occur
between the analytical model and the vehicle as manufactured. Because
an actual vehicle is not involved in the assessment of compliance using
Alternatives 3 and 4, these alternatives might not account for
variation or flaws in material properties, or quality control
deficiencies in the manufacturing build processes. A design that looks
acceptable ``on paper'' or in theory might not turn out so as assessed
by testing an actual vehicle. To the extent possible, NHTSA prefers to
test actually-manufactured vehicles, to assess not only the design of
the vehicle, but the real-world production of the vehicle.
    In short, deficiencies in vehicle performance due to poor quality
control of manufacturing processes, sub-standard quality of supplied
materials or errors in the engineering analysis underlying the vehicle
design can be better discovered when an actual vehicle is tested than
under a compliance system using Alternatives 3 and 4.
    For these reasons, this final rule is based on the complete vehicle
test of ECE R.66 to determine compliance. NHTSA is incorporating ECE
R.66's compliance framework in a manner that meets the requirements of
MAP-21 and the requirements and considerations of NHTSA's Safety Act.
The agency emphasizes that FMVSS No. 227 does not preclude
manufacturers from using the alternative compliance methods of ECE R.66
to certify their vehicles. As explained in the NPRM,\114\ although an
engineering analysis model would not be appropriate as the agency's
method of assessing the compliance of vehicles with a Federal motor
vehicle safety standard manufacturers are not required to use NHTSA's
test as the basis for their certification. While the agency's test
defined in the proposed regulatory test would be an objective test
capable of determining which vehicles meet the minimum requirements,
manufacturers can use other methods (such as the alternative compliance
options in ECE

R.66) in certifying the compliance of their own vehicles.
---------------------------------------------------------------------------

    \114\ 79 FR 46117; August 6, 2014.
---------------------------------------------------------------------------

    Manufacturers using ECE R.66's alternatives are responsible for
ensuring that the vehicles will meet the requirements of FMVSS No. 227
when tested by NHTSA per the agency's procedures. However,
manufacturers certifying compliance of their own vehicles have much
more detailed information regarding their own vehicles and production
methods than NHTSA and should be capable of using other methods to
certify their vehicles. If manufacturers are confident that the data
obtained by using the test methods described in ECE R.66's Alternatives
1 through 4 assure conformance with the standard just as the complete
vehicle test does, nothing precludes them from using those alternatives
to certify their vehicles to FMVSS No. 227 with confidence.

b. Regulatory Alternatives

    In deciding on the approach adopted by this final rule, NHTSA
examined the following alternatives.
1. FMVSS No. 216
    NHTSA considered the requirements of FMVSS No. 216, ``Roof crush
resistance.'' FMVSS No. 216 applies to vehicles with a GVWR of 4,536 kg
(10,000 lb) or less (light vehicles), and specifies a test that applies
localized static loads to the upper front corners of a vehicle's roof
and windshield area. The large buses covered under this final rule are
larger/heavier than light vehicles and are more likely to roll along a
longitudinal vehicle axis than yaw and pitch. Thus, in an actual
rollover involving one of these vehicles, the entire length of the
vehicle is loaded as in the ECE R.66 test. NHTSA believes the ECE R.66
test is more representative of a real-world rollover of a large bus
than the FMVSS No. 216 test since the ECE R.66 test imparts loads along
the full length of the vehicle.
    In addition, the ECE R.66 test is a dynamic test in which
``survival space'' performance requirements are specially designed for
the large bus interior. There are also additional safety issues
specific to the vehicles covered by this rule (opening of emergency
exits, detachment of windows from their mountings) that can be
evaluated in the dynamic event. Since two-thirds of rollover fatalities
are due to ejections, addressing these additional safety issues is
vital to addressing the safety problem in rollovers. Therefore, the
agency believes that the ECE R.66 test addresses more of the safety
needs of a large bus rollover crash than the FMVSS No. 216 test.
2. FMVSS No. 220
    FMVSS No. 220 is a school bus roof crush standard that places a
uniformly distributed vertical force pushing directly downward on the
top of the bus with a platen that is 914 mm (36 inches) wide and that
is 305 mm (12 inches) shorter than the length of the bus roof. The
standard specifies that when a uniformly distributed load equal to 1.5
times the unloaded vehicle weight is applied to the roof of the
vehicle's body structure through a force application plate, the
downward vertical movement at any point on the application plate shall
not exceed 130 mm (5.125 inches) and the emergency exits must be
operable during and after the test.
    The agency included FMVSS No. 220 in its research into rollover
structural integrity for large buses and, in the NPRM, tentatively
decided the ECE R.66 test was preferable to the FMVSS No. 220 for
motorcoaches for several reasons. First, the agency determined that an
ECE R.66 based test is more suitable for the vehicles covered by FMVSS
No. 227 than an FMVSS No. 220-based test because a significant portion
of fatalities in the subject buses result from occupant ejections.
Unlike school buses, the subject motorcoach and other large buses
operate intercity routes and typically travel at higher speeds than
school buses transporting children to a local educational facility.
Further, many of the motorcoaches and subject intercity buses are
designed with a higher center of gravity than school buses and have
larger windows. These characteristics can lead to a higher incidence of
occupant ejections during rollovers involving the non-school buses. The
agency believed dynamic rollover test in ECE R.66 affords the agency
the opportunity to better evaluate ejection-related factors such as the
emergency exits and side window glazing retention during a rollover
crash.
    After considering the comments, NHTSA makes the following
decisions. As previously discussed, the agency is permitting
manufacturers of school bus derivative buses to certify compliance with
FMVSS No. 220 as an alternative to certifying to the ECE R.66 test in
FMVSS No. 227. FMVSS No. 220 has been proven to adequately ensure roof
crush protection in vehicles designed to meet the FMVSSs applying to
school buses, so allowing school bus derivative buses to meet FMVSS No.
220 avoids redundancy in the FMVSS. NHTSA is not permitting FMVSS No.
220 as an alternative to FMVSS No. 227 for buses other than school bus
derivative buses. The dynamic test in FMVSS No. 227 is a more
representative test of real-world rollovers for motorcoaches and buses
other than school buses and addresses safety needs arising in rollovers
of those vehicles that FMVSS No. 220 does not address.

c. Additional MAP-21 Considerations

    In addition to the MAP-21 provisions discussed previously in this
document, MAP-21 also directs NHTSA to consider the best available
science, potential impacts on seating capacity, and potential impacts
on the size/weight of motorcoaches.\115\ Further, MAP-21 directs the
agency to consider combining the various motorcoach rulemakings
contemplated by MAP-21 and to avoid duplicative benefits, costs, and
countermeasures.\116\
---------------------------------------------------------------------------

    \115\ See MAP-21 section 32703(e)(1).
    \116\ See id. at section 32706(b)-(c).
---------------------------------------------------------------------------

    NHTSA considered the best available science in developing this
final rule. The agency developed this rule based on FMVSS No. 220 and
ECE R.66 test studies NHTSA conducted on large bus rollover structural
integrity (see section IV of the NPRM), and after considering advanced
glazing countermeasures (see May 6, 2016 (81 FR 27904) NPRM, supra, and
``Motor Coach Glazing Retention Test Development For Occupant Impact
During A Rollover,'' Martec Technical Report # TR-06-16, Rev 4, August
2006 \117\). NHTSA considered FMVSS No. 216 and ECE R.66 alternative
compliance methods (see sections VI of the NPRM).
---------------------------------------------------------------------------

    \117\ Docket No. NHTSA-2002-11876-0015.
---------------------------------------------------------------------------

    Coach USA provided the only response to the NPRM request for
comment on the impact of added vehicle weight to seating capacity. It
requested NHTSA to consider that further increases to motorcoach weight
could make it difficult for all operators to carry a full passenger
load while still complying with applicable vehicle and axle weight
limits. NHTSA does not believe this final rule will adversely impact
seating capacity. Large bus buyers expect maximum seating capacity with
adequate luggage capacity for a given floor space or vehicle length.
Estimates for structural weight added to a bus to meet this final rule
are based on usage of steel.\118\ NHTSA is aware that other methods of
reinforcing the structure (such as the use of high strength steel
sections, rigid polyurethane foam filling to reinforce and stabilize
thin walled hollow sections, and optimized designs that

redistribute the impact loads and enhance the energy absorption
capability) may enable a large bus to withstand greater crash forces
without increasing as much weight.\119\
---------------------------------------------------------------------------

    \118\ Final Regulatory Evaluation Large Bus Structural Integrity
FMVSS No. 227; NHTSA Office of Regulatory Analysis and Evaluation,
National Center for Statistics and Analysis. Available in the docket
for this rule.
    \119\ See Lilley, K. and Mani, A., ``Roof-Crush Strength
Improvement Using Rigid Polyurethane Foam,'' SAE Technical Paper
960435, 1996. Available at: https://subscriptions.sae.org/content/960435/, see also Liang, C. and Le, G. Optimization of bus rollover
strength by consideration of the energy absorption ability.
International Journal of Automotive Technology. Vol. 11.(2) 173-185.
Available at: https://www.springerlink.com/content/tk824863k66w0228/export-citation/.
---------------------------------------------------------------------------

    Through this final rule and our accompanying Final Regulatory
Evaluation (FRE), the agency has considered the potential impacts of
this rule on the size and weight of motorcoaches and other large buses
affected by this rule.\120\ As described further in the next section
(and in the FRE), we have considered potential weight increases to
motorcoaches as a cost of this final rule due to increased fuel
consumption. In the accompanying FRE, we have quantified and accounted
for this increased fuel consumption cost in our cost-benefit analysis
of the rule. After considering all costs, including the potential
weight increase, the agency concludes that the requirements in this
final rule will be cost-beneficial.
---------------------------------------------------------------------------

    \120\ ``Motorcoach'' in this paragraph has the meaning given in
MAP-21 (OTRBs).
---------------------------------------------------------------------------

    NHTSA has designed this rule to complement the agency's 2013 final
rule on FMVSS No. 208 requiring seat belts for passenger seating
positions. The seat belt rule will result in increasing numbers of
passengers buckling up on large buses. As they do so, more and more
will be retained within the passenger compartment in crashes. NHTSA has
designed it so that FMVSS No. 227 and FMVSS No. 208 work together to
provide a survival space to the passengers retained within the
passenger compartment due to the seat belts. NHTSA has also designed
this final rule bearing in mind NHTSA's May 6, 2016 NPRM,\121\ issued
pursuant to section 32703(b)(2) of MAP-21, that proposes to adopt an
advanced glazing standard for large buses (OTRBs and non-OTRBs with a
GVWR greater than 11,793 kilograms (26,000 pounds)). The reinforcements
to the superstructure and bus body to meet FMVSS No. 227's structural
integrity requirements will increase the likelihood that anti-ejection
advanced glazing installed consistent with section 32703(b)(2) will be
retained in a rollover crash.
---------------------------------------------------------------------------

    \121\ 81 FR 27904, supra.
---------------------------------------------------------------------------

    Finally, NHTSA is avoiding duplicating benefits, costs, and
countermeasures in the motorcoach rulemakings of MAP-21. As described
above, the agency believes that the requirements of FMVSS No. 227 work
together with the passenger seat belt requirements of FMVSS No. 208 and
complements an advanced glazing standard. As described in the
accompanying FRE, the agency has estimated the benefits and costs of
this final rule while considering the effect of seat belts on the
subject buses and the application of the ESC rule.

XIV. Lead Time

    The agency proposed a compliance date of 3 years after publication
of the final rule for FMVSS No. 227. MAP-21 (in section 32703(e))
directs that the rulemaking shall apply to all motorcoaches
manufactured more than 3 years after the date on which the regulation
is published as a final rule.
Comments Received
    IC Bus agreed with the proposed 3-year lead time. Van Hool stated
``that for the requirements for the strength of superstructure
according to the Series of Amendment 01 of UN Regulation No. 66 . . . a
transition period of 144 months was granted.''
Agency Response
    This final rule adopts the 3-year compliance date. To enable
manufacturers to certify to the new requirements as early as possible,
optional early compliance with the standard is permitted. The 3-year
date for motorcoaches is required by MAP-21. If Van Hool was requesting
a 144-month lead time, NHTSA declines the request as contrary to MAP-
21. Further, the commenter provided no information to support or
further explain their interest in or need for a 144-month (12-year)
lead time for the effective date of FMVSS No. 227. Van Hool and others
currently manufacture buses for sale to European countries including
Italy, France, Germany, Poland, and the Netherlands.\122\ Each of these
countries is listed under the 1958 Agreement as countries granting
approval to buses meeting the requirements of ECE R.66. Since Van Hool
already designs buses for ECE R.66 requirements, NHTSA believes that
the commenter has a good foundation for manufacturing buses that meet
the structural requirements of FMVSS No. 227.
---------------------------------------------------------------------------

    \122\ Information from review of Van Hool website press release
information. Obtained February 24, 2017 (https://www.vanhool.be/ENG/bedrijsfinfo/historiek/historiek2009-20.html).
---------------------------------------------------------------------------

    NHTSA concludes that three years of lead time will be sufficient
for bus manufacturers generally to make the necessary changes. The lead
time for motorcoaches is mandated by MAP-21, but it is also reasonable.
Van Hool and other manufacturers of buses that already meet ECE R.66
may have to improve the type of latches used on emergency exits, and
improve the mounting of side windows, but three years will be ample
time to complete the design, testing, and changes in production
necessary to certify compliance to the FMVSS No. 227 requirements.
    For manufacturers whose buses do not already meet ECE R.66, NHTSA
believes that manufacturers will need to make structural design changes
to their large bus models either by changing the strength of the
sidewall and glazing frame material or the material's physical
dimensions (i.e., thickness or width). Per the results of our test
program conducted in support of this rulemaking, newer buses may need
stronger side pillars to meet the glazing retention requirements, and
redesigned mechanisms on roof exits and side window exits to ensure
that they do not release during the impact. We believe that these
changes can be done within three years. Further, we note that under 49
CFR 571.8(b), manufacturers of buses other than motorcoaches built in
two or more stages and alterers are provided an additional year of lead
time for manufacturer certification and compliance.

XV. Retrofitting Used Buses

    The agency stated in the NPRM that, based on the agency's tests of
older buses, major structural changes to the vehicle's entire sidewall
and roof structure would be needed for some existing buses to meet the
proposed rollover structural integrity requirements. NHTSA believed
that the structural changes are likely to be cost-prohibitive, making
retrofitting for rollover structural integrity impractical. NHTSA
requested comments on the feasibility, benefits, and costs of any
potential requirement to retrofit existing buses to meet FMVSS No. 227.
Comments Received
    Almost half of the respondents to the NPRM commented on the
retrofit issue and all opposed retrofitting. IC Bus, Daimler Trucks,
Van Hool, ABA, Greyhound, Coach USA, Prevost, and Advocates raised
concerns about retrofit. They believed that the work involved in
retrofitting a bus to meet FVMSS No. 227, even just the glazing aspects
of the standard, would entail impracticable and unreasonable reworking
of the bus structure. The complications of retrofit are exacerbated,
they stated, by having to deal with the condition of existing

structures, the lack of original design information, and possible need
for Federal oversight and approval of each bus's structural rework.
Agency Response
    NHTSA is not specifying a retrofit requirement. The agency did not
receive or discover any new information that would alter the previous
determination that retrofitting of existing buses would be
impracticable and unreasonable. The agency continues to expect the
structural changes needed for retrofitting to be substantial, and to
involve significant costs beyond those estimated in our regulatory
analysis for new buses. The cost impacts would likely have a
substantial adverse impact on a significant number of small entities
(e.g. , owner-operators of buses used for transport), without a
commensurate safety benefit. Therefore, NHTSA reaffirms the earlier
decision not to require retrofit of used buses to meet FMVSS No. 227.

XVI. Overview of Costs and Benefits

    Based on the FARS data over the 15-year period between 2004 and
2018, there were a total of 56 fatal rollover crashes involving the bus
types covered by this final rule, resulting in 189 occupant fatalities.
Beyond the benefits attributable to the rules on seat belts and ESC for
these vehicles, NHTSA estimates this final rule will save approximately
3 lives annually (undiscounted) if 15 percent of occupants use seat
belts, and approximately 2 lives annually (undiscounted) if 90 percent
of occupants use seat belts.\123\ NHTSA estimates this final rule will
reduce the number of seriously injured occupants by approximately 4
annually. These estimated benefits are distinct from the passenger
protections attributable to the seat belt and ESC requirements for
buses covered by this final rule and are conservative estimates. As
explained later in this section, these estimates do not count possible
benefits to belted occupants who were saved from injury or fatality
because of the survival space provided by FMVSS No. 227.
---------------------------------------------------------------------------

    \123\ The FRE prepared in support of this final rule assumes
that the seat belt use rate on large buses will be between 15
percent and the percent use in passenger vehicles, which was 90
percent in 2009. To maintain consistency with the seat belt rule, we
have used the same low belt usage rate estimate of 15 percent from
that rule, and the same source of information to establish the high
belt usage rate estimate (See 2009 National Occupant Protection Use
Survey. More information at: https://www-nrd.nhtsa.dot.gov/pubs/811100.pdf).
---------------------------------------------------------------------------

    While belted occupants will benefit from a survival space, unbelted
occupants will benefit as well. The belted occupant will mostly benefit
from reduced intrusion of structures and objects into the survival
space. The unbelted occupants will benefit from a reduced risk of
occupant ejection. Given these differences in how occupants will
benefit from the rule, we have estimated benefits for each group
separately.
    Also, the benefits estimates will vary by seat belt use. Available
research regarding seat belt use suggests that it can be highly
variable. NHTSA has estimated the lower end of seat belt use at 15
percent and the upper end of seat belt use at 90 percent. The agency
assumes that, initially, belt use will be closer to the lower end (15
percent) because passengers are not yet accustomed to seat belts on the
buses. Many large buses in use do not have seat belts, and passengers
have not been educated about the benefits of buckling up in a large
bus.
    NHTSA estimates that at 3 percent and 7 percent discount rates,
1.87 to 2.45 equivalent lives are saved annually if 15 percent of
occupants use seat belts and 1.46 to 1.92 equivalent lives are saved
annually if 90 percent of occupants use seat belts (see Table 13
below).
    The agency estimates that, assuming steel is used to strengthen the
vehicle structure to comply with the requirements in this final rule,
material costs for each vehicle will range from $325 to $591 and cost
between $0.71 million and $1.30 million to equip the entire new large
bus fleet annually (see Table 14 below). NHTSA further estimates that,
if steel is used to comply, the total weight increase will range from
181 to 356 kg (399 to 784 lb) and cost an additional $1,862 to $4,790
in fuel per vehicle over the lifetime of the vehicle. The total fuel
cost for the new fleet is estimated to be $4.10 million to $10.54
million. The total costs will be approximately $4.81 million to $11.84
million annually. The cost per equivalent life saved is estimated to be
between $2.48 million and $6.38 million (see Table 15 below) and net
economic benefit is estimated to be between $8.25 million and $23.31
million in 2020 dollars.
    The available information shows this final rule is cost beneficial.
The above estimates for the cost per equivalent life of this rule vary
due to uncertainties regarding seat belt use rates and the incremental
increase in weight that is necessary to meet FMVSS No. 227. For seat
belt use, NHTSA believes that the projected net impact on the economy
will be closer to the estimates for the 15 percent belt use rates than
the 90 percent belt use rate, as explained above. A large portion of
the costs of this structural integrity rule is dependent on this
incremental increase in weight. NHTSA does not have more specific
information regarding the likely weight increase to these vehicles.
    The agency believes that the cost effectiveness of this rule is not
very sensitive to changes in belt usage rates because belted passengers
will still realize safety benefits because of this rule. Many serious
injuries that occur in large bus crashes can occur despite a
passenger's use of a safety belt. For example, while belted passengers
may not be ejected, they can still be struck by the collapsing side
wall of the bus. Therefore, even though increasing seat belt usage
rates may mean that more passenger ejections (and fatalities) will be
prevented by seat belts (consequently reducing the number of prevented
ejections attributable to FMVSS No. 227), the final rule will still be
effective in preventing serious injuries to belted passengers. Thus, we
expect that the monetized value of the benefits of this rule is not
very sensitive to fluctuations in seat belt use--even though the type
of benefit will change.\124\
---------------------------------------------------------------------------

    \124\ For further information, see the FRE prepared in support
of this final rule. The FRE 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.

                   Table 13--Estimated Annual Benefits
                        [Equivalent lives saved]
------------------------------------------------------------------------
                                       15% belt use       90% belt use
------------------------------------------------------------------------
3% Discount.......................               2.45               1.92
7% Discount.......................               1.87               1.46
------------------------------------------------------------------------

                    Table 14--Estimated Annual Costs
                             [2020 Dollars]
------------------------------------------------------------------------

------------------------------------------------------------------------
Potential Costs:
    Material Costs Per Vehicle.  $325 to $591.
    Material Costs, Total New    $0.71 million to $1.30 million.
     Fleet.
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.
------------------------------------------------------------------------

                    Table 15--Cost per Equivalent Life Saved in Millions (M) of 2020 Dollars
----------------------------------------------------------------------------------------------------------------
                                                   15% belt use    15% belt use    90% belt use    90% belt use
                                                    3% discount     7% discount     3% discount     7% discount
----------------------------------------------------------------------------------------------------------------
Cost (New Vehicle + Fuel).......................      6.08-11.84       4.81-9.34      6.08-11.84       4.81-9.34
Equivalent Lives Saved..........................            2.45            1.87            1.92            1.46
Cost per Equivalent Life Saved..................       2.48-4.83       2.57-4.99       3.17-6.17       3.28-6.38
----------------------------------------------------------------------------------------------------------------

    The cost of reinforcing the roof strength and structural integrity
of these vehicles to meet the requirements in this final rule are
predominantly dependent upon the material and weight increases
necessary to reinforce the superstructure. NHTSA estimates that the
countermeasures may include stronger roof and side walls, shock
resistant latches for emergency exits, and improved window mounting. As
mentioned above, these material costs for each vehicle are estimated to
be between $325 and $591. However, while the agency assumes in these
estimates that steel is applied to reinforce the vehicle structure, the
agency is aware that other methods of reinforcing the structure (such
as the use of high strength steel sections, rigid polyurethane foam
filling to reinforce and stabilize thin-walled, hollow sections, and
optimized designs that redistribute the impact loads and enhance the
energy absorption capability) may enable a vehicle to withstand greater
crash forces without adding as much weight.\125\ Therefore, while our
analysis has assumed the use of steel, the agency is aware that there
may be other countermeasures that weigh less--which could result in
lower fuel costs--than we have currently estimated, over the lifetime
of the vehicle.
---------------------------------------------------------------------------

    \125\ See Lilley, K. and Mani, A., ``Roof-Crush Strength
Improvement Using Rigid Polyurethane Foam,'' SAE Technical Paper
960435, 1996. Available at: https://subscriptions.sae.org/content/960435/, see also Liang, C. and Le, G. Optimization of bus rollover
strength by consideration of the energy absorption ability.
International Journal of Automotive Technology. Vol. 11.(2) 173-185.
Available at: https://www.springerlink.com/content/tk824863k66w0228/export-citation/.
---------------------------------------------------------------------------

    The agency also notes that, in addition to the quantifiable
benefits mentioned above, there are other benefits arising from this
final rule. Our economic analysis of this rule is only able to
calculate the benefits that can be realized above and beyond the
benefits attributable to previously-published final rules, in
particular, the November 25, 2013 (78 FR 70416) seat belt final rule.
In other words, we are only able to estimate the benefits to passengers
whose serious and fatal injuries were not prevented by seat belts. When
an occupant who would have been seriously or fatally injured in a bus
crash is estimated as saved from such injury by a countermeasure
previously made effective for that occupant (e.g., a seat belt), NHTSA
no longer estimates additional benefits for that particular passenger.
    However, we believe that some people who were saved by the seat
belt could still benefit from this rule, as the poor structural
integrity of a bus could contribute toward a fatality or an injury for
this saved occupant. It is important to note that while the agency
could estimate benefits to belted passengers who still were seriously
injured or killed notwithstanding the seat belts, because of our
practices we do not estimate what additional benefits could be realized
by passengers who were already considered saved from serious and fatal
injury due to the seat belts. As the agency is unaware of any available
information that would enable the agency to quantify this latter
benefit, the agency's economic analysis of this rule only estimates the
benefits to occupants who were not saved by the seat
belts.126 127
---------------------------------------------------------------------------

    \126\ Thus, we believe our estimate of benefits is conservative,
undercounting possible benefits to occupant who were saved from
fatal ejection by seat belts but still seriously injured by
collapsing structure or unrestrained heavy vehicle components
intruding into the survival space.
    \127\ This final rule will also theoretically result in
additional benefits by functioning to support NHTSA's proposed rule
on FMVSS No. 217a, supra, to mitigate ejection risks through
installation of advanced glazing. This final rule will provide for
the structural foundation, or anchor, to retain advanced glazing to
the vehicle when that advanced glazing is installed per the proposed
FMVSS No. 217a. While this final rule on FMVSS No. 227 could result
in associated benefits regarding FMVSS No. 217a, we have not
quantified them for this rulemaking proceeding.
---------------------------------------------------------------------------

XVII. Rulemaking Analyses and Notices

Executive Order (E.O.) 12866, E.O. 13563, and DOT Rulemaking Procedures

    NHTSA has considered the impact of this final rule under Executive
Orders 12866 and 13563, and DOT administrative rulemaking orders and
procedures. This final rule is not considered significant and was not
reviewed by the Office of Management and Budget under E.O. 12866.
    This final rule increases roof strength and structural integrity
for certain large bus types by establishing requirements for
maintaining survival space and emergency exit operability during and
after a rollover structural integrity test. This final rule specifies a
test procedure that tilts the vehicle on a platform until the vehicle
becomes unstable and rolls over onto a level concrete impact surface.

    NHTSA has prepared a FRE for this final rule.\128\ Beyond the
benefits attributable to rules on seat belts for this same group of
vehicles and ESC, NHTSA estimates that this final rule will save
approximately 3.12 equivalent lives annually if seat belt usage among
occupants is 15 percent, and approximately 2.45 equivalent lives
annually if seat belt usage is 90 percent. The total cost of making the
necessary structural changes, and of lifetime fuel costs, will be
approximately $4.81 million to $11.84 million annually (for the entire
new fleet). The net cost per equivalent life saved is estimated to be
between $2.48 million and $6.38 million. The benefits, costs, and other
impacts of this rulemaking are discussed at length in the FRE.
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    \128\ Final Regulatory Evaluation Large Bus Structural Integrity
FMVSS No. 227; NHTSA Office of Regulatory Analysis and Evaluation,
National Center for Statistics and Analysis. Available in the docket
for this rule.
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Executive Order 13609: Promoting International Regulatory Cooperation

    The policy statement in section 1 of Executive Order 13609
provides, in part: The regulatory approaches taken by foreign
governments may differ from those taken by U.S. regulatory agencies to
address similar issues. In some cases, the differences between the
regulatory approaches of U.S. agencies and those of their foreign
counterparts might not be necessary and might impair the ability of
American businesses to export and compete internationally. In meeting
shared challenges involving health, safety, labor, security,
environmental, and other issues, international regulatory cooperation
can identify approaches that are at least as protective as those that
are or would be adopted in the absence of such cooperation.
International regulatory cooperation can also reduce, eliminate, or
prevent unnecessary differences in regulatory requirements.
    As mentioned in this preamble, the agency has considered regulatory
approaches taken by foreign governments (namely, the European Union in
ECE R.66) and decided to base FMVSS No. 227 on ECE R.66. In addition to
the goal of reducing unnecessary differences in regulatory requirements
between the U.S. and its trading partners, the agency has found the ECE
R.66 test to be the most suitable test available for ensuring a minimum
reasonable level of protection for passengers traveling in buses that
are associated with the highest crash risk. While NHTSA has determined
that it is not able to adopt the entirety of ECE R.66 and has adopted
emergency exits latching requirements which are not in ECR R.66, the
agency has explained its rationale for its decisions in the relevant
sections of this document.

Regulatory Flexibility Act

    Pursuant to the Regulatory Flexibility Act (5 U.S.C. 601 et seq.,
as amended by the Small Business Regulatory Enforcement Fairness Act
(SBREFA) of 1996), whenever an agency is required to publish a notice
of rulemaking for any proposed or final rule, it must prepare and make
available for public comment a regulatory flexibility analysis that
describes the effect of the rule on small entities (i.e., small
businesses, small organizations, and small governmental jurisdictions).
The Small Business Administration's regulations at 13 CFR part 121
define a small business, in part, as a business entity ``which operates
primarily within the United States.'' (13 CFR 121.105(a)). No
regulatory flexibility analysis is required if the head of an agency
certifies that the rule will not have a significant economic impact on
a substantial number of small entities. The SBREFA amended the
Regulatory Flexibility Act to require Federal agencies to provide a
statement of the factual basis for certifying that a rule will not have
a significant economic impact on a substantial number of small
entities.
    NHTSA has considered the effects of this rulemaking action under
the Regulatory Flexibility Act. Per 13 CFR 121.201, the Small Business
Administration's size standards regulations used to define small
business concerns, manufacturers of the vehicles covered by this rule
fall under North American Industry Classification System (NAICS) No.
336111, Automobile Manufacturing, which has a size standard of 1,000
employees or fewer. NHTSA estimates that there are 26 manufacturers of
these types of vehicles in the United States (including manufacturers
of motorcoaches, cutaway buses, second-stage motorcoaches, and other
types of large buses covered by this rule). Using the size standard of
1,000 employees or fewer, we estimate that approximately 10 of these 26
manufacturers are considered small businesses.
    I certify that this final rule will not have a significant economic
impact on small entities. First, the agency estimates that the
incremental costs to each vehicle would be $325 to $591 per unit to
meet the rule. This incremental cost would not constitute a significant
impact given that the average cost of the vehicles covered by this rule
ranges from $200,000 to $400,000. Further, these incremental costs,
which are very small compared to the overall cost of the vehicle, can
ultimately be passed on to the purchaser and user.
    In addition, the agency believes that certifying compliance with
the rule will not have a significant impact on the small manufacturers.
These entities have various options available that they may use to
certify compliance with the standard.
    This final rule adopts ECE R.66's compliance framework in a manner
that meets the requirements of MAP-21 and the requirements and
considerations of NHTSA's Safety Act. The standard will not provide for
NHTSA's use of Alternatives 1 through 4 to determine compliance.
However, this does not mean that manufacturers must use the complete
vehicle test to certify their vehicles. To the contrary, the Safety Act
requires manufacturers to ensure their vehicle meet all applicable
FMVSSs, and that they certify the compliance of their vehicle with
applicable FMVSS. The Safety Act specifies that manufacturers may not
certify if in exercising reasonable care the manufacturer has reason to
know the certificate is false or misleading. This means a manufacturer
may use the alternative compliance methods of ECE R.66 to certify its
vehicles if it can do so in exercising reasonable care. While
manufacturers must ensure that their vehicles will meet the
requirements of FMVSS No. 227 when NHTSA tests the vehicles in
accordance with the test procedures specified in the standard, they do
not have to conduct the test described in FMVSS No. 227 to certify that
compliance.\129\
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    \129\ Under the Vehicle Safety Act, a manufacturer can avoid
civil penalties associated with a noncompliance if it showed that it
exercised due care in certifying its vehicles. A showing of due care
can be based on engineering analyses, computer simulations, and the
like, and NHTSA will assess the due care upon which the
certification is made by evaluating, among other factors, the size
of the manufacturer and its resources. Even small manufacturers,
however, are responsible for having a reasonable idea as to whether
their vehicles comply with the standard. They are responsible for
proclaiming that their vehicles will comply should NHTSA test their
vehicle. The alternatives discussed in this section provide those
bases for certification.
---------------------------------------------------------------------------

    One option is to certify compliance using modeling or engineering
analyses (such as a plastic hinge analysis of portal frames of the
vehicle). ECE R.66 itself accounts for and accommodates this compliance
option, and this approach has been used for years by European
manufacturers in meeting ECE R.66. An engineering analysis model is
less preferable to the dynamic test procedure specified in this rule as
the agency's method of assessing the

compliance of vehicles with an FMVSS, since the agency may not know
enough about the assumptions to use in the model or whether the model
in fact represents the subject vehicle as manufactured. However, unlike
NHTSA, manufacturers have access to much more information regarding
their own vehicles and can analyze information of sufficient detail and
breadth about vehicle design, material characteristics and production
processes to form a basis for their certification. They can use their
own methods for certifying compliance of their vehicles, such as
engineering analyses to certify their vehicles. If the basis for their
certification is made using reasonable care, they will have met the
requirement of section 30115 to certify the compliance of their
vehicles. If they used reasonable care in certifying and manufacturing
the vehicles, the likelihood that the vehicles will pass the FMVSS No.
227 compliance test when tested by NHTSA according to the standard is
very high.
    The manufacturer could test body sections of the vehicle, as
contemplated by ECE R.66, Alternatives 1 and 2. The manufacturer could
``section'' the vehicle or otherwise obtain a body section
representative of the vehicle and of the weakest section of the
vehicle. It could base its certification on these tests, without
testing a full vehicle. As discussed above, they know their vehicles
best, and can test the section most at risk of not meeting FMVSS No.
227 to make sure the vehicle would meet the standard when tested by
NHTSA in the complete vehicle test. This process will allow small
manufacturers to test parts of the vehicle for compliance, and use
their engineering expertise to calculate that the bus will meet the
standard when NHTSA tests it in accordance with the procedure specified
in FMVSS No. 227.
    In the event small manufacturers elect to conduct a test of a full
vehicle, there are various methods available to reduce the costs of the
test. One such method is by testing a vehicle which is not completely
new. As the requirements in this final rule pertain to structural
integrity, we believe that a manufacturer could test the relevant body
design on an old bus chassis or other underlying structure, and could
sufficiently assess and certify the compliance of the vehicle's
structural integrity to FMVSS No. 227. Similarly, the agency believes
that more costly parts of the vehicle (such as the engine and other
portions of the powertrain) could be replaced in a complete vehicle
test of a bus with ballast equal to the weight of the absent
components. The small manufacturer could base its certification on such
testing, which do not involve a destructive test of an actual vehicle.
    NHTSA notes that the product cycle of large buses subject to FMVSS
No. 227 is much longer than other vehicle types. With a longer product
cycle, the agency believes that the costs of certification for
manufacturers would be further reduced as the costs of conducting
compliance testing and the relevant analyses could be spread over a
significantly longer period.
    This rule may affect operators of the buses--some of which may be
small businesses--but only indirectly as purchasers of these vehicles.
As mentioned above, NHTSA anticipates that the impact on these
businesses will not be significant because (assuming that additional
steel is used for compliance) the expected price increase of the
vehicles used by these businesses is small ($325 to $591 for each
vehicle (vehicles valued between $200,000 and $400,000)). NHTSA
anticipates that fuel costs for these businesses will increase between
$1,862 and $4,790 (in 2020 dollars) per vehicle over its lifetime.
These expected increases in costs are small in comparison to the cost
of each of these vehicles. Given that these costs will equally affect
all operators, the small operators will be able to pass these costs
onto their consumers. This final rule does not require retrofitting of
vehicles on the road.

Executive Order 13132 (Federalism)

    NHTSA has examined this final rule pursuant to Executive Order
13132 (64 FR 43255; Aug. 10, 1999) and has determined that no
additional consultation with States, local governments, or their
representatives is mandated beyond the rulemaking process. The agency
has concluded that the rule does not have sufficient federalism
implications to warrant consultation with State and local officials or
the preparation of a federalism summary impact statement. The rule does
not have ``substantial direct effects on the States, on the
relationship between the national government and the States, or on the
distribution of power and responsibilities among the various levels of
government.''
    NHTSA rules can have preemptive effect in two ways. First, the
National Traffic and Motor Vehicle Safety Act contains an express
preemption provision that when a motor vehicle safety standard is in
effect under this chapter, a State or a political subdivision of a
State may prescribe or continue in effect a standard applicable to the
same aspect of performance of a motor vehicle or motor vehicle
equipment only if the standard is identical to the standard prescribed
under the chapter. 49 U.S.C. 30103(b)(1). It is this statutory command
by Congress that preempts any non-identical State legislative and
administrative law address the same aspect of performance.
    The express preemption provision described above is subject to a
savings clause under which ``[c]ompliance with a motor vehicle safety
standard prescribed under this chapter does not exempt a person from
liability at common law.'' 49 U.S.C. 30103(e). Pursuant to this
provision, State common law tort causes of action against motor vehicle
manufacturers that might otherwise be preempted by the express
preemption provision are generally preserved. However, the Supreme
Court has recognized the possibility, in some instances, of implied
preemption of State common law tort causes of action by virtue of
NHTSA's rules--even if not expressly preempted.
    This second way that NHTSA rules can preempt is dependent upon the
existence of an actual conflict between an FMVSS and the higher
standard that would effectively be imposed on motor vehicle
manufacturers if someone obtained a State common law tort judgment
against the manufacturer--notwithstanding the manufacturer's compliance
with the NHTSA standard. Because most NHTSA standards established by an
FMVSS are minimum standards, a State common law tort cause of action
that seeks to impose a higher standard on motor vehicle manufacturers
will generally not be preempted. However, if and when such a conflict
does exist--for example, when the standard at issue is both a minimum
and a maximum standard--the State common law tort cause of action is
impliedly preempted. See Geier v. American Honda Motor Co., 529 U.S.
861 (2000).
    Pursuant to Executive Order 13132, NHTSA has considered whether
this rule could or should preempt State common law causes of action.
The agency's ability to announce its conclusion regarding the
preemptive effect of one of its rules reduces the likelihood that
preemption will be an issue in any subsequent tort litigation.
    To this end, the agency has examined the nature (e.g., the language
and structure of the regulatory text) and objectives of this final rule
and does not foresee any potential State requirements that might
conflict with it. NHTSA does not intend that this final rule preempt
state tort law that would effectively

impose a higher standard on motor vehicle manufacturers than that
established by this rule. Establishment of a higher standard by means
of State tort law would not conflict with the standard issued by this
final rule. Without any conflict, there could not be any implied
preemption of a State common law tort cause of action.

National Environmental Policy Act

    NHTSA has analyzed this final rule for the purposes of the National
Environmental Policy Act. The agency has determined that implementation
of this action will not have any significant impact on the quality of
the human environment.

Paperwork Reduction Act

    Under the procedures established by the Paperwork Reduction Act of
1995, a person is not required to respond to a collection of
information by a Federal agency unless the collection displays a valid
Office of Management and Budget (OMB) control number. This rulemaking
would not establish any new information collection requirements.

National Technology Transfer and Advancement Act

    Under the National Technology Transfer and Advancement Act of 1995
(NTTAA) (Pub. L. 104-113), ``all Federal agencies and departments shall
use technical standards that are developed or adopted by voluntary
consensus standards bodies, using such technical standards as a means
to carry out policy objectives or activities determined by the agencies
and departments.'' Voluntary consensus standards are technical
standards (e.g., materials specifications, test methods, sampling
procedures, and business practices) that are developed or adopted by
voluntary consensus standards bodies, such as SAE International. The
NTTAA directs this agency to provide Congress, through OMB,
explanations when the agency decides not to use available and
applicable voluntary consensus standards.
    While the agency is not aware of any voluntary standards that exist
regarding rollover structural integrity for the large buses covered by
this final rule, the agency has examined the applicable European Union
standard (ECE R.66). As discussed extensively above, we have adopted an
ECE R.66-based test, in part, to avoid requiring manufacturers to meet
fundamentally different rollover requirements than those required in
the European Union. The areas of this final rule that differ from ECE
R.66, and the reasons in support, are extensively discussed in the
earlier sections of this preamble.

Executive Order 12988

    With respect to the review of the promulgation of a new regulation,
section 3(b) of Executive Order 12988, ``Civil Justice Reform'' (61 FR
4729, February 7, 1996) requires that Executive agencies make every
reasonable effort to ensure that the regulation: (1) Clearly specifies
the preemptive effect; (2) clearly specifies the effect on existing
Federal law or regulation; (3) provides a clear legal standard for
affected conduct, while promoting simplification and burden reduction;
(4) clearly specifies the retroactive effect, if any; (5) adequately
defines key terms; and (6) addresses other important issues affecting
clarity and general draftsmanship under any guidelines issued by the
Attorney General. This document is consistent with that requirement.
    Pursuant to this order, NHTSA notes as follows. The issue of
preemption is discussed above in connection with E.O. 13132. NHTSA
notes further that there is no requirement that individuals submit a
petition for reconsideration or pursue other administrative proceeding
before they may file suit in court.

Unfunded Mandates Reform Act

    The Unfunded Mandates Reform Act of 1995 requires agencies to
prepare a written assessment of the costs, benefits and other effects
of proposed or final rules that include a Federal mandate likely to
result in the expenditure by State, local or tribal governments, in the
aggregate, or by the private sector, of more than $158 million annually
(adjusted for inflation to 2020 dollars with base year of 1995). This
final rule will not result in expenditures by State, local or tribal
governments, in the aggregate, or by the private sector in excess of
$158 million annually.

Plain Language

    Executive Order 12866 and E.O. 13563 require each agency to write
all rules in plain language. Application of the principles of plain
language includes consideration of the following questions:
     Have we organized the material to suit the public's needs?
     Are the requirements in the rule clearly stated?
     Does the rule contain technical language or jargon that
isn't clear?
     Would a different format (grouping and order of sections,
use of headings, paragraphing) make the rule easier to understand?
     Would more (but shorter) sections be better?
     Could we improve clarity by adding tables, lists, or
diagrams?
     What else could we do to make the rule easier to
understand?
    If you have any responses to these questions, please inform us.

Regulation Identifier Number (RIN)

    The Department of Transportation assigns a regulation identifier
number (RIN) to each regulatory action listed in the Unified Agenda of
Federal Regulations. The Regulatory Information Service Center
publishes the Unified Agenda in April and October of each year. You may
use the RIN contained in the heading at the beginning of this document
to find this action in the Unified Agenda.

Privacy Act

    Anyone is able to search the electronic form of all comments
received into any of our dockets by the name of the individual
submitting the comment (or signing the comment, if submitted on behalf
of an association, business, labor union, etc.). You may review DOT's
complete Privacy Act Statement in the Federal Register published on
April 11, 2000 (65 FR 19477-78).

List of Subjects in 49 CFR Part 571