Federal Motor Vehicle Safety Standards; Seat Belt Assembly Anchorages, School Bus Passenger Seating and Crash Protection, 66686-66698 [2010-27312]

Agencies

• National Highway Traffic Safety Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 75, Number 209 (Friday, October 29, 2010)]
[Rules and Regulations]
[Pages 66686-66698]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-27312]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. NHTSA-2008-0613]
RIN 2127-AK49


Federal Motor Vehicle Safety Standards; Seat Belt Assembly 
Anchorages, School Bus Passenger Seating and Crash Protection

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

ACTION: Final rule; response to petitions for reconsideration.

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SUMMARY: In this final rule, we respond to petitions for 
reconsideration of a final rule published on October 21, 2008, which 
upgraded NHTSA's school bus passenger crash protection requirements. 
This document denies most of the requests in the petitions for 
reconsideration.
    To the extent we grant petitions, we make slight changes to the 
regulatory text of the October 2008 final rule to clarify the rule. We 
make clearer the procedure specifying how we will measure the height of 
school bus passenger torso belts, and we are clarifying that a 
requirement that seat belts be integral to the passenger seat (a 
requirement adopted to reduce the

[[Page 66687]]

likelihood of passengers getting injured by or tangled in loose belts) 
also applies to seats that have wheelchair positions or side emergency 
doors behind them, even if the seats are in the last row of vehicles. 
We are also slightly revising the procedure for testing the self-
latching requirement for school bus seat cushions, to specify the 
weight that is placed on the seat cushion in Newtons, to specify that 
the downward force is applied in a one to five second timeframe, and to 
specify that activation of the self-latching mechanism is assessed 
using the seat cushion retention test. Those provisions make the 
language more consistent with that of a pre-existing seat cushion 
retention test in the standard.

DATES: The effective date of this final rule is April 27, 2011.
    Petitions for reconsideration: Petitions for reconsideration of 
this final rule must be received not later than December 13, 2010.

ADDRESSES: Petitions for reconsideration of this final rule must refer 
to the docket and notice number set forth above and be submitted to the 
Administrator, National Highway Traffic Safety Administration, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: For non-legal issues, Mr. Charles 
Hott, Office of Crashworthiness Standards (telephone: 202-366-0247) 
(fax: 202-366-4921), NVS-113. For legal issues, Ms. Dorothy Nakama, 
Office of the Chief Counsel (telephone: 202-366-2992) (fax: 202-366-
3820), NCC-112. These officials can be reached at the National Highway 
Traffic Safety Administration, 1200 New Jersey Avenue, SE., Washington, 
DC 20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Background--October 21, 2008 Final Rule
II. Petitions for Reconsideration and Comments--Overview
III. Petitions for Reconsideration of Amendments Adopted by Final 
Rule
    a. Stringency of FMVSS No. 210 Requirements
    b. Applying FMVSS No. 207 to Small School Buses
    c. Minimum Lateral Anchorage Separation
    d. Clarifications of Torso Anchorage Location
    e. Integration of the Seat Belt Anchorages Into the Seat 
Structure
    f. Seat Cushion Latches
IV. Comments on Decisions Not Involving Regulatory Text
    a. Requiring Large School Buses To Have Seat Belts
    b. Defining a ``Small'' School Bus
    c. Preemption
V. Rulemaking Analyses and Notices

I. Background--October 21, 2008 Final Rule

    In a final rule published on October 21, 2008 (73 FR 62744, NHTSA 
Docket No. 2008-0163), we (NHTSA) upgraded the school bus \1\ occupant 
protection requirements of various Federal motor vehicle safety 
standards, primarily by amending FMVSS No. 222, ``School bus passenger 
seating and crash protection'' (49 CFR 571.222), and also by amending 
the requirements of FMVSS No. 207, ``Seating systems,'' No. 208, 
``Occupant crash protection,'' and No 210, ``Seat belt assembly 
anchorages,'' relating to the strength of the seating system and seat 
belt anchorages.\2\ \3\
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    \1\ ``School bus'' is defined in 49 CFR 571.3 as a bus that is 
sold, or introduced in interstate commerce, for purposes that 
include carrying students to and from school or related events, but 
does not include a bus designed and sold for operation as a common 
carrier in urban transportation. A ``bus'' is a motor vehicle, 
except a trailer, designed for carrying more than 10 persons. In 
this final rule, when we refer to ``large'' school buses, we refer 
to those school buses with gross vehicle weight ratings (GVWRs) of 
more than 4,536 kilograms (kg) (10,000 pounds (lb)). These large 
school buses may transport as many as 90 students. ``Small'' school 
buses are school buses with a GVWR of 4,536 kg (10,000 lb) or less. 
Generally, these small school buses seat 15 persons or fewer, or 
have one or two wheelchair seating positions.
    \2\ The October 21, 2008 final rule includes a detailed 
explanation of the rationale for the rulemaking. See 73 FR 62744.
    \3\ The notice of proposed rulemaking (NPRM) preceding this 
final rule was published on November 21, 2007 (72 FR 65509; Docket 
No. NHTSA-2007-0014).
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    The final rule provided the most up-to-date information known to 
the agency on seat belts on large school buses. In the final rule, we 
explained the findings of NHTSA's school bus research program conducted 
in response to the Transportation Equity Act for the 21st Century (TEA-
21) and discussed principles that the agency weighed about belts on 
large buses. The document affirmed that States should have the choice 
of ordering seat belts on their large (over 4,536 kg (10,000 pounds 
(lb)) GVWR) school buses, but also affirmed that accident data and 
crash research findings did not support a conclusion that a Federal 
mandate for seat belts on large school buses was warranted. The final 
rule adopted performance and installation requirements for voluntarily-
installed seat belts on large school buses to ensure the strength of 
the anchorages and that the belts will not degrade 
compartmentalization.\4\
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    \4\ FMVSS No. 222 provides passenger crash protection using the 
``compartmentalization'' concept. Compartmentalization ensures that 
passengers are cushioned and contained by the seats in the event of 
a school bus crash by requiring school bus seats to be positioned in 
a manner that provides a compact, protected area surrounding each 
seat. If a seat is not compartmentalized by a seat back in front of 
it, compartmentalization must be provided by a padded and protective 
restraining barrier. The seats and restraining barriers must be 
strong enough to maintain their integrity in a crash, yet flexible 
enough to be capable of deflecting in a manner which absorbs the 
energy of the occupant. They must meet specified height requirements 
and be constructed, by use of substantial padding or other means, so 
that they provide protection when they are impacted by the head and 
legs of a passenger. Compartmentalization minimizes the hostility of 
the crash environment and limits the range of movement of an 
occupant. The compartmentalization approach ensures that high levels 
of crash protection are provided to each passenger independent of 
any action on the part of the occupant.
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    The October 21, 2008 final rule's most significant changes to FMVSS 
No. 222 involved:
     Requiring small school buses, which are currently required 
to have lap belts for passenger seating positions, to have a lap/
shoulder belt at each passenger seating position (a ``lap/shoulder 
belt'' is a Type 2 seat belt assembly under FMVSS No. 209 (see S3));
     Increasing the minimum seat back height requirement from 
508 millimeters (mm) (20 inches (in)) from the seating reference point 
(SgRP) to 610 mm (24 in) for all school buses;
     Incorporating performance requirements and other 
specifications into the standard to ensure that lap/shoulder belts in 
small school buses and voluntarily-installed lap and lap/shoulder belts 
in large school buses have sufficient strength and are compatible with 
compartmentalization; and,
     Requiring all school buses that have seat bottom cushions 
that are designed to flip up or be removable, typically for easy 
cleaning, to have a self-latching mechanism.
    The first three upgrades were based on the findings of NHTSA's 
school bus research program, discussed in detail in the preamble to the 
final rule, which the agency conducted in response to TEA-21.\5\ 
Requiring small school buses to have lap/shoulder belts for all 
passengers and raising the seat back height on all school buses to 610 
mm (24 in) makes the highly protective interior of the school bus even 
safer. Further, as new designs of lap/shoulder belts intended for large 
school buses are emerging in the marketplace, the third initiative will 
require lap/shoulder belts to be complementary with 
compartmentalization, ensuring that the high level of passenger crash 
protection is enhanced and not degraded by any seat belt system.
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    \5\ The fourth initiative, for self-latching mechanisms, 
responds to an NTSB recommendation to NHTSA (H-84-75).

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[[Page 66688]]

II. Petitions for Reconsideration and Comments--Overview

    NHTSA received petitions for reconsideration of the final rule 
from: school bus manufacturers Blue Bird Corporation (Blue Bird) and IC 
Bus, LLC (IC); seat manufacturers C.E. White Company (CEW) and M2K, LLC 
(M2K); and from the Marietta City School District (MCSD) of Ohio. With 
regard to changes to the regulatory text adopted by the October 2008 
final rule, petitioners requested NHTSA to reconsider: The stringency 
of the FMVSS No. 210 requirements adopted for large school buses (IC 
believed the requirements were unnecessarily high); the application of 
FMVSS No. 207 to small school bus seats with lap/shoulder belts (Blue 
Bird believed the standard need not apply to the vehicles); the 
requirement for seat width (M2K believed all seats should be allowed to 
be a minimum of 257 mm (10.1 in) wide; the specifications in the final 
rule for measuring the school bus torso belt adjusted height (Blue Bird 
requested further clarification); the types of seats which must have 
integral seat belts (Blue Bird suggested that the requirement should 
apply to seats that have wheelchair positions or side emergency doors 
behind them); and, the test requirements for self-latching seat 
cushions (Blue Bird, M2K, MCSD).
    With regard to several issues that were either outside the scope of 
this rulemaking or otherwise not properly the subject of a petition for 
reconsideration, NHTSA received comments from Public Citizen (PC), CEW 
and IC. PC requested that the agency require lap/shoulder seat belts in 
large school buses and that NHTSA investigate ``whether 
compartmentalization can effectively restrain occupants in side-impact 
and rollover crashes.'' CEW and IC asked NHTSA to change the GVWR cut 
off delineating ``large'' school buses from ``small'' school buses, 
from 4,536 kg (10,000 lb) GVWR to 6,577 kg (14,500 lb) (suggested by 
CEW) or 7,257 kg (16,000 lb) (suggested by IC). PC and the American 
Association for Justice (AAJ) objected to the agency's discussion in 
the final rule of the assessment of the law relating to preemption of 
State tort law.\6\
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    \6\ Apparently interpreting the discussion as an assertion of 
preemption of state tort law, AAJ objected to the discussion just as 
it has objected to similar discussions in other NHTSA rulemaking 
actions since 2007. Public Citizen expressed similar objections to 
the preemption discussion in the preamble.
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III. Petitions for Reconsideration of Amendments Adopted by Final Rule

a. Stringency of FMVSS No. 210 Requirements

    Final Rule--In the final rule, we specified one anchorage strength 
requirement (i.e., 13,334 N (3,000 lb) applied to the torso and pelvic 
body blocks) for both large and small school buses with lap/shoulder 
seat belts. We explained in the final rule our reasons for keeping a 
single requirement in FMVSS No. 210 (73 FR at 62765), notwithstanding 
data from the post-NPRM testing 7 8 that indicated that a 
large school bus pulse generates about 67 percent of the FMVSS No. 210 
force, assuming two belted seating positions. (For three belted 
positions, it was determined that the same peak dynamic load generates 
44 percent of the FMVSS No. 210 force.\9\) Included among our reasons 
for keeping a single requirement in FMVSS No. 210, equal to the more 
severe small school bus case, was that the 13,334 N (3,000 lb) FMVSS 
No. 210 requirement provides a safety margin we deem appropriate, and 
that a single requirement facilitates better efficiency in the testing. 
Further, NHTSA's testing and the comments from school bus seat 
manufacturers led us to conclude that the 13,334 N (3,000 lb) 
requirement would not be difficult to meet. We also noted that 
commenters did not provide cost and weight data showing any cost 
savings resulting from a reduced loading for a larger class of school 
buses.
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    \7\ ``NHTSA Technical Analysis to Support the Final Rule 
Upgrading Passenger Crash Protection in School Buses,'' September 
2008.
    \8\ ``NHTSA Vehicle Research and Test Center's Technical Report 
on Dynamic and Quasi-Static Testing for Lap/Shoulder Belts in School 
Buses,'' September 2008.
    \9\ This calculation assumes a bench seat with three fixed or 
flex-seating positions and that three 5th percentile female 
occupants would be generating the dynamic loading.
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    With regard to safety performance, we set the requirement at 13,334 
N (3,000 lb) based in part on the recognition that anchorage strength 
provides the foundation upon which the restraint system is built. We 
believed that there was a safety need to require the anchorages on 
large school buses to meet the more stringent FMVSS No. 210 requirement 
because the safety margin provided by the requirement better ensures 
that the anchorages will be strong enough to deal with loading in 
excess of that exerted on the anchorages in the NHTSA research program, 
either because of use or misuse by larger occupants, the stiffness and 
mass of the vehicle (e.g., vehicles closer in mass to a small school 
bus than a large school bus will experience a more severe crash pulse), 
or because the crash could be more severe than the crash 
characteristics considered in the research program.
    Petitions for Reconsideration--In its petition for reconsideration, 
IC requested that NHTSA reduce the anchorage strength requirement from 
13,334 N (3,000 lb) to \2/3\ of the small bus requirement (the current 
FMVSS No. 210 requirement), due to our recognition in the final rule 
that large school buses experience lower crash forces than do small 
school buses. (IC had previously expressed this view in its comments on 
the NPRM.) IC believed that NHTSA's testing and analysis suggest that a 
more appropriate strength requirement for large school buses would be 
\2/3\ of the small bus requirement. IC stated that it only builds large 
school buses ``and could specifically develop a seating system that 
effectively protects the occupant and is more cost effective than the 
seat for a small school bus.'' Based on its conversations with current 
seat suppliers, IC estimated that there could be a cost savings to a 
school district of $10-$15 per seat, or $220-$330 per typical 66 
passenger bus. The petitioner stated that setting the FMVSS No. 210 
requirement higher than necessary will drive up the cost of vehicles.
    NHTSA's Response--We are denying IC's request. The petitioner's 
views are repetitive of views it expressed in comments to the NPRM, to 
which NHTSA responded in the preamble of the final rule (73 FR at 
62765).
    We reiterate the agency's position discussed in the final rule. We 
agree that the mass of the bus plays an important role in the amount of 
force that seat belt anchorages undergo in a crash. However, as we 
explained in the final rule preamble, we did not and do not believe 
that the data from the school bus research program should be used to 
define the upper bounds of the performance that should be prescribed 
for the seat belt anchorages. The frontal crash test into a fixed rigid 
barrier represents a crash between two vehicles of the same weight. The 
data, generated from a controlled laboratory environment, are 
inherently bounded to some degree in representing the force to which 
the anchorages could be exposed in a real-world environment.
    In the laboratory sled test, the force measured on the anchorages 
was produced using test dummies of a certain mass, a crash pulse of a 
certain severity, and particular school bus seats. The final rule 
referenced sled tests with 50th percentile male dummies in school bus 
seats and a crash pulse representing a 30 mph full frontal rigid 
barrier crash

[[Page 66689]]

test of a 71 passenger Type C (conventional) school bus. The GVWR of 
this bus was 13,154 kg (29,000 lb) and the seat anchorage loads 
obtained were specific to the type and weight of the bus, crash type, 
and the size of the seated occupants. The anchorage loads would be 
higher for larger occupants (such as 95th percentile adult males which 
correspond to the size of some high school football players) and school 
buses closer in weight to a small school bus than the larger Type C 
school bus. As discussed in the final rule, since anchorage strength 
provides the foundation upon which the restraint system is built, there 
is a vital need to require the anchorages to meet the more stringent 
yet practicable FMVSS No. 210 requirements to ensure an adequate safety 
factor. Having this safety margin better ensures that the anchorages 
will be strong enough to withstand loads in excess of the load produced 
by the sled test, loads possibly resulting from ``worst case'' 
scenarios, e.g., the use or misuse of the seat belts by larger 
occupants, use of an inordinately stiff and heavy seat, or a collision 
of high severity.
    The 13,334 N (3,000 lb) FMVSS No. 210 load has been used to test 
seat belt anchorages for decades. Seat belt anchorages certified as 
meeting the requirements have a reliable and proven safety record. Our 
testing indicated that the same FMVSS No. 210 strength requirements for 
small and large school buses are practicable and would not be difficult 
to meet, a finding which was supported by comments from school bus seat 
manufacturers. While the crash pulse experienced by large school buses 
may be less severe than that of small school buses in similar 
collisions, applying the FMVSS No. 210 loads to seat belts that are 
voluntarily installed on large school buses will increase the 
likelihood that any seat belt that is installed will perform well under 
a wide range of crash conditions, occupant sizes, and seat belt use/
misuse conditions.
    Although it may appear that the anchorages of large school bus 
seats are required to be designed to a greater safety margin than those 
of small school bus seats, it is important to note that the additional 
FMVSS No. 207 seat inertial loading is only applied to small school bus 
seats during the FMVSS No. 210 test. We estimated that the combined 
FMVSS No. 210 and FMVSS No. 207 loads applied simultaneously exceed the 
actual measured total dynamic load on a small school bus seat with 
three seating positions by 50 percent and is approximately equivalent 
to the actual dynamic loads on a seat with two seating positions.\10\ 
This additional FMVSS No. 207 seat load is not applied to large school 
bus seats--in part due to the wider safety margin (133 percent) 
associated with the FMVSS No. 210 strength requirement.
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    \10\ See 73 FR at 62758.
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    IC stated in its petition that most, if not all, bus manufacturers 
already build in a ``safety margin'' when producing their vehicles to 
ensure that the vehicle will meet the requirements in a compliance 
test, and so the ```safety margin' that NHTSA has built into the 
regulation is compounded by the vehicle manufacturer's safety margin.'' 
While we are encouraged to know that some manufacturers build a safety 
margin in their vehicles, the agency cannot rely on a safety margin 
that is voluntary on the part of the manufacturer for its regulations.
    IC presented no new data that supports its position that the 
anchorage strength for large school buses should be less than that for 
small school buses, except for an estimate of cost savings for a ``two-
thirds load seat,'' which we find tenuous. As IC itself noted in its 
petition, ``At this time it is difficult to accurately estimate the 
potential cost savings that would be associated with seating systems 
that meet \2/3\ of the current FMVSS 210 requirement because such 
seating systems are not currently designed or available.''
    Cost savings in the range of $10-$15 per seat appears high; the 
petitioner did not submit information explaining the basis for this 
cost estimate. As stated in the final rule preamble, we do not believe 
it is difficult from an engineering standpoint to meet the FMVSS No. 
210 load requirement. We are not convinced that a two-thirds load seat 
would be engineered that differently from a full load FMVSS No. 210 
seat. Further, as explained above, even if the seats are different, we 
believe that any added structure or reinforcement of the seat is a 
necessary measure to increase the likelihood of adequate performance of 
the seat and seat belt anchorages in misuse situations or in severe 
crashes.
    IC further stated that the loading requirement for a flex seat, 
which has a seating position designed for a small occupant, should not 
be required to meet the same loading requirements as the current FMVSS 
No. 210. IC suggested that the load requirements for the ``small 
occupant seating position'' (see definition, FMVSS No. 222) be based on 
the weight of a 95th percentile 10-year-old multiplied by the measured 
pulse deceleration, which the petitioner suggested to be 13.5 g.
    We are maintaining the FMVSS No. 210 anchorage load requirements at 
all flex-seat seating positions even though we acknowledge that some of 
the seating positions may likely contain smaller riders (and not 
exclusively larger riders) when the seat is at full capacity. However, 
as previously stated, anchorage strength provides the foundation upon 
which the restraint system is built and so providing a higher factor of 
safety as it relates to the applied test load for large occupants is 
not unreasonable. We established that our standard requires a minimum 
level of anchorage strength for larger occupants (or larger students) 
since it is conceivable that, when riding alone, they may have the 
option to sit in the center seating position of a flex-seat, for 
example, where the seat belt anchorage may potentially be loaded to a 
relatively high level in a crash scenario. Additionally, our testing of 
flex-seats suggests that there are no practicability concerns for 
meeting the FMVSS No. 210 load requirements.
    IC suggested that there is a ``distinctive difference'' between 
school buses with a GVWR greater than 7,257 kg (16,000 lb) as compared 
to school buses with a GVWR less than or equal to 7,257 kg (16,000 lb). 
``School buses with a GVWR of less than 16,000 lbs. are most often 
based on a passenger or light truck vehicle. School buses with a GVWR 
greater than 16,000 lbs. are most often an integrated vehicle designed 
specifically for that application and components and systems are 
usually similar to medium and heavy duty trucks.'' IC stated that if 
NHTSA is not inclined to lower the FMVSS No. 210 strength requirement 
for school buses greater than 4,536 kg (10,000 lb) GVWR, IC petitioned 
to change the requirement for school buses with a greater than 7,257 kg 
(16,000 lb) GVWR to two-thirds of the current FMVSS No. 210 strength 
requirement.
    NHTSA is declining IC's suggestion to lower the FMVSS No. 210 
strength requirements for school buses with a GVWR greater than 7,257 
kg (16,000 lb) for the same reasons we have denied IC's petition to 
lower the FMVSS No. 210 requirements for large school buses overall. 
The crash pulse used in our sled tests where the maximum seat anchor 
loads during the sled tests were approximately two-thirds of those in a 
FMVSS No. 210 test was that of a school bus with a GVWR of 13,154 kg 
(29,000 lb) in a frontal crash into fixed rigid barrier. The seat 
anchor forces would be greater than those measured in the sled tests 
with a more severe crash pulse (e.g., a lighter school bus crashing 
into a heavier and stiffer vehicle) and with

[[Page 66690]]

heavier occupants in heavier seats. IC provided no data to suggest that 
school buses with a GVWR greater than 7,257 kg (16,000 lb) will have 
seat belt anchorage loads two-thirds that of the current FMVSS No. 210 
requirement under all passenger and crash conditions. We believe that a 
single criterion for application of FMVSS No. 210 loads to school bus 
seats is practicable. The anchorage strength provides the foundation 
upon which the restraint system is built and so providing a higher 
factor of safety as it relates to the applied test load for large 
school buses is not unreasonable. In addition, we are not applying the 
additional FMVSS No. 207 seat inertial loads to large school buses due 
to the wider safety margin associated with the uniform FMVSS No. 210 
requirement. We require the additional FMVSS No. 207 loads to be 
applied simultaneously with the FMVSS No. 210 loads for small school 
buses.
    With regard to IC's suggestion that the GVWR cut-off between large 
and small school buses should be set at a higher GVWR level, the 
agency's response to this and a related CEW suggestion is discussed 
later in this preamble. The agency is declining to make the change in 
this final rule.
    In conclusion, for the reasons discussed above, we have determined 
that the FMVSS No. 210 loading requirement is appropriate for seat 
belts voluntarily installed on large school buses. Therefore, in this 
final rule, we will not lower the seat belt anchorage loads for large 
school buses.

b. Applying FMVSS No. 207 to Small School Buses

    Final Rule--In the final rule, we decided it was necessary to apply 
FMVSS No. 207 to small school buses with lap/shoulder belts to minimize 
the possibility of the seats' failure by forces acting on them as a 
result of vehicle impact.\11\ This decision disagreed with Blue Bird's 
comment on the NPRM, in which Blue Bird recommended not applying FMVSS 
No. 207 to small school buses. Blue Bird believed that FMVSS No. 207 
was excessive because ``the required FMVSS 210 loading captures the 
seat inertial loading at a deceleration level exceeding the 20g 
required by FMVSS 207.''
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    \11\ S1, Purpose and Scope, of FMVSS No. 207 states: ``This 
standard establishes requirements for seats, their attachment 
assemblies, and their installation to minimize the possibility of 
their failure by forces acting on them as a result of vehicle 
impact.''
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    In the final rule, we discussed our reasons for concluding that 
there was a safety need to apply FMVSS No. 207 to small school buses. 
Among the reasons, we explained that the dynamic seat anchor loads 
measured in NHTSA's sled testing of small school bus seating systems 
(tests using a small school bus crash pulse with restrained test 
dummies in the bench seat under evaluation, and belted and unbelted 
test dummies in seats aft of the bench seat under evaluation) matched, 
or replicated with a reasonable safety margin, the total load on the 
seat from the combined FMVSS No. 207 and FMVSS No. 210 loads. In the 
agency's analysis, we included the rear loading to school bus seats 
from belted and unbelted occupants in the aft row.
    Petition for Reconsideration--In its petition for reconsideration, 
Blue Bird disagreed with the final rule's requirement to apply FMVSS 
No. 207 loading to small school buses with lap/shoulder seat belt 
assemblies. Blue Bird stated that the additional load is not necessary 
if the loading from rear passengers is not taken into consideration, 
and provided an analysis of the loading without contact from rear 
passengers to the seat back.
    Blue Bird stated that neither the NPRM nor the final rule mention 
any intent to have small school bus passenger seats withstand the loads 
resulting from contact by passengers seated behind them. Blue Bird 
expressed the belief that its analysis shows FMVSS No. 210 loading of 
small school bus passenger seats equipped with lap/shoulder seat belt 
assemblies captures the seat's inertial loading defined by FMVSS No. 
207 with room to spare. Therefore, in Blue Bird's view, applying FMVSS 
No. 207's loading simultaneously is excessive. Blue Bird further argued 
that if the loading resulting from contact by occupants rearward of the 
seat is a concern, a separate rulemaking pertinent to that condition 
should be initiated.
    NHTSA's Response--We are denying this request. To justify its view 
that FMVSS No. 210 alone was sufficient to ensure loading by the lap/
shoulder seat belt assemblies, Blue Bird presented an analysis in its 
petition for reconsideration of the final rule similar to what Blue 
Bird submitted as its comment to the NPRM. In the analysis in its 
petition for reconsideration of the final rule, Blue Bird applied the 
ratio of small to large school bus loading reported in the final rule 
and assumed that there is no rear loading to school bus seats from 
belted occupants in the rear row (or argued that such rear loading 
should not be considered). It estimated the anchorage loads using the 
measured belt loads and computed inertial loads for the seat under 
consideration without including the rear loading from belted occupants 
in the rear row.
    We believe that Blue Bird's assertion that rear loading should be 
excluded from consideration is incorrect. The agency's analysis used 
the maximum loads measured directly at the seat attachment to the 
vehicle (Table 3.1 in the Technical Analysis supporting the final rule, 
see Docket No. NHTSA-2008-0163) and thus did not rely on a theoretical 
summation of belt loads and inertial loads as Blue Bird's did. Our 
analysis of the test data showed that the seat anchorage loads for a 
given crash pulse and seat type depend on the number of occupants in 
lap/shoulder belts, the occupants' size, and the contact from 
passengers rearward of the seat.
    The agency's sled testing of school bus seats used a small school 
bus crash pulse and replicated a typical real world configuration of 
seats with belted 50th percentile male dummies in one row of school bus 
seats and both belted and unbelted 50th percentile male dummies in the 
row directly rear of the seats under consideration. In all the tests 
where there were belted or unbelted occupants in the row of seats to 
the rear of the seating row where the attachment loads were measured, 
the rear row occupants contacted the seats in front of them. The total 
seat anchorage loads measured in these sled tests included the seat 
back loading from the rear seat occupants. Therefore, the assertion 
that the agency did not take these loads into consideration is not 
correct. Blue Bird's analysis did not take into consideration all the 
loads experienced by the seat during a crash event, since it does not 
account for the loading of the seat from rear occupants.
    Our analysis of the results of the sled testing showed that the 
combined FMVSS Nos. 207 and 210 loading levels match the dynamic 
loading level fairly closely for the seat configuration with two belted 
50th percentile male occupants in the front and rear rows. This 
analysis supports the fact that the FMVSS No. 207 load is not redundant 
for small school buses and should be considered along with the FMVSS 
No. 210 loads.
    We do not agree with Blue Bird's view that the agency made ``no 
mention of any intent to have small school bus passenger seats 
withstand the loading resulting from contact by passengers seated 
behind them'' in either the NPRM or final rule. The petitioner stated 
that we did not provide notice that we would be considering loads from 
rear passengers when we proposed to apply the FMVSS No. 207 
requirements to

[[Page 66691]]

small school bus passenger seats. We disagree, as the purpose and scope 
of FMVSS No. 207 is to minimize the possibility of the failure of the 
seat's attachment to the vehicle as a result of forces during a vehicle 
impact. As such, it would have been remiss of the agency not to have 
considered all forces, including the forces on the seat from rear 
occupants, particularly unbelted occupants striking the seat backs, in 
its analysis.
    Throughout the rulemaking, NHTSA discussed the importance it 
attached to developing performance criteria that accounted for the 
interaction between fore-and-aft passengers in school bus seats with 
lap/shoulder belts. The quasi-static test adopted by the final rule for 
testing school bus passenger seats with lap/shoulder belts was 
expressly developed to recognize the interaction between fore-and-aft 
passengers in bus seats. In the NPRM, NHTSA stated that the quasi-
static test requirement was proposed ``to test school bus seats with 
lap/shoulder belts, to help ensure that seat backs incorporating lap/
shoulder belts are strong enough to withstand the forward pull of the 
torso belts in a crash and the forces imposed on the seat from unbelted 
passengers to the rear of the belted occupants.'' NPRM, 72 FR at 65514. 
(See also final rule, 73 FR at 62766. The agency developed the quasi-
static test to ensure ``that seat backs incorporating lap/shoulder 
belts are strong enough to withstand the forward pull of the torso 
belts in a crash and the forces imposed on the seat from unbelted 
passengers.'')
    In the NPRM and final rule (73 FR at 62766), we also described the 
sequence of events that the agency sought to replicate with the quasi-
static test. NHTSA observed this sequence in a sled test involving two 
unbelted 50th percentile male dummies positioned behind a school bus 
bench seat containing two restrained 50th percentile male dummies.
    1. The knees of the unbelted dummy to the rear struck the back of 
the forward seat, causing some seat back deflection.
    2. The seat back was loaded by the shoulder belt of the restrained 
dummy in the forward seat.
    3. The shoulder belt load was reduced as the seat back to which it 
was attached deflected forward.
    4. The shoulder belt loads reduced to approximately zero when the 
unbelted dummies' chests struck the forward seat back.
    5. The forward seat back deflected further forward as the energy 
from the unbelted dummies was absorbed.
    With the emphasis NHTSA gave throughout the rulemaking to the 
forces imparted on the seating system from passengers to the rear of 
the belted occupant, the agency provided ample notice that it would be 
considering the force generated by rear-seated occupants on a seating 
system in determining whether FMVSS No. 207 should apply to school bus 
seating systems.\12\
---------------------------------------------------------------------------

    \12\ In the NPRM, while considering the need for the FMVSS No. 
207 test requirements for school buses, the agency compared the seat 
anchor loads in a dynamic sled test with belted occupants in the 
subject seat and unbelted occupants in the rear with the seat anchor 
loads generated in the proposed FMVSS Nos. 210, 207, and 222 quasi-
static load tests. See 72 FR 65518.
---------------------------------------------------------------------------

    Considering the above, the agency provided notice that the load 
from the rear seat passenger would be considered. For those reasons, we 
will not revisit this issue with a separate rulemaking action to 
include the load from those passengers. Blue Bird's petition for 
reconsideration on the FMVSS No. 207 issue is thus denied.

c. Minimum Lateral Anchorage Separation

    Final Rule--In the final rule, S5.1.7 of FMVSS No. 222 was amended 
to require that each passenger seating position with a lap/shoulder 
restraint system have a minimum seat belt lower anchor lateral spacing 
of: 280 mm (11.0 in) for flexible occupancy seats with the maximum 
number of occupants; and 330 mm (13 in) for flexible occupancy seats 
with the minimum occupancy configuration and for seats with fixed 
occupant capacity. Under FMVSS No. 210, movable (e.g., sliding) 
anchorages for an occupant seating position cannot be capable of being 
closer than 165 mm (6.5 in).
    Petition for Reconsideration--In its petition for reconsideration, 
M2K states that the final rule's minimum lateral anchorage spacing 
requirement (280 mm for flexible occupancy seats with the maximum 
number of occupants; and 330 mm for flexible occupancy seats with the 
minimum occupancy configuration and for seats with fixed occupant 
capacity) is substantially more restrictive of seat design than the 
current FMVSS No. 210 requirement (S4.3.1.4), which specifies a minimum 
lateral spacing of 165 mm (6.5 in). M2K stated that data do not exist 
to demonstrate that the FMVSS No. 210 anchorage spacing is 
insufficient. It believed that the minimum lateral anchorage spacing 
should be the same distance as the hip breadth specified in the final 
rule update of FMVSS No. 208, which specifies the following occupant 
anthropometry in S7.1.4 of that standard: Hip breadth of 50th 
percentile 6-year-old child = 213 mm (8.4 in); hip breadth of 50th 
percentile 10-year-old child = 257 mm (10.1 in).
    M2K asks that the minimum lateral anchorage spacing be equal to the 
hip width of a 10-year-old (257 mm (10.1 in)) for all school bus 
passenger seats regardless of whether the seats are designed for 
``fixed'' or ``flexible'' occupancy seat configurations. Despite being 
less than the 280 mm (11.0 in) requirement, M2K argued that the 257 mm 
(10.1 in) value established more stringent design criteria for school 
buses than the current FMVSS No. 210 requirement of 165 mm (6.5 in) for 
passenger vehicles and light trucks. The petitioner stated its belief 
that the 257 mm (10.1 in) value achieves NHTSA's stated goal of 
increasing protection for child occupants by preventing compressive 
loading of the iliac crests. M2K recommended that this recommendation 
would not exclude any of the three current ``flex-seat'' designs 
produced by IMMI, CE White, and M2K. M2K believed that the 257 mm (10.1 
in) minimum spacing should apply to both fixed and laterally moveable 
anchorages on lap/shoulder seat belts for flex-seats, as well as for 
lap belts on fixed-capacity seats.
    NHTSA's Response--We are denying this request. The agency specified 
a minimum lateral anchorage spacing to provide better pelvic load 
distribution for school bus passengers in frontal impacts. When 
anchorages are narrower than the occupant pelvis, the lap belt can wrap 
around the iliac crests and cause compressive loading. As discussed 
below, a minimum lateral spacing of 257 mm (10.1 in) recommended by M2K 
does not meet our objective of ensuring that excessive compressive 
loads are not induced by the school bus seat belt anchorages; the 
petitioner provided no information supporting its contrary view.
    To determine the appropriate value for lateral anchorage separation 
for the final rule, the agency measured the lower anchorage spacing of 
several school bus seats with flexible and fixed occupancy. We 
determined that flexible occupancy seat designs in maximum occupancy 
configuration are able to achieve a lateral separation of the lower 
anchorages of no less than 280 mm (11.0 in) simultaneously in any 
seating position. This minimum lateral spacing of the lower anchorages 
specified in the final rule for flex-seats in its maximum occupancy 
configuration is slightly larger than the hip breadth of a typical 10-
year-old child (257 mm or 10.1 in) and provides better pelvic load 
distribution than the 257 mm (10.1 in) lateral anchorage spacing. The 
257 mm (10.1 in) lateral anchorage spacing

[[Page 66692]]

recommended by M2K will be insufficient for occupants larger than an 
average 10-year-old, such as a 95th percentile 10-year-old with a hip 
breadth of 275 mm (10.8 in \13\). Further, reducing the anchorage 
spacing to 257 mm (10.1 in) as recommended by the petitioner would not 
gain additional seating positions for typical school bus seats. M2K 
provided no data or support for its assertion that a 257 mm (10.1 in) 
minimum lateral anchorage spacing requirement would prevent compressive 
loading of the iliac crests.
---------------------------------------------------------------------------

    \13\ Snyder et al., ``Anthropometry of infants, children and 
youth to age 18 for product safety design.'' University of Michigan 
report UM-HSRI-77-17, 1977, https://mreed.umtri.umich.edu/mreed/downloads/anthro/child/Snyder_1977_Child.pdf.
---------------------------------------------------------------------------

    The 330 mm (13 in) minimum lateral lower anchor spacing specified 
in the final rule for flexible occupancy seats with the minimum 
occupancy configuration and for seats with fixed occupant capacity were 
based on our measurements of typical school bus seats. The 330 mm (13 
in) lower anchor spacing is practicable and corresponds to the hip 
width of 5th percentile female and results in no loss in occupancy for 
typical school bus seat widths of 762, 991, and 1,143 mm (30, 39, and 
45 in). In addition, we believe the 330 mm (13 in) minimum lateral 
anchor spacing will result in good load distribution on the pelvis for 
adult size occupants while the 257 mm (10.1 in) lateral anchor spacing 
recommended by the petitioner may result in excessive compressive loads 
on the pelvis.
    We also note that M2K appears to believe that the minimum anchorage 
spacing does not apply to sliding anchorages.\14\ That understanding is 
not correct. In determining the minimum width for sliding anchorages, 
we will assess the minimum anchorage separation simultaneously 
achievable by the anchorages. That is, a sliding anchorage may increase 
the anchorage separation for one position while decreasing the 
separation for the other seating position. However, the configuration 
that results in the reduced anchorage separation must meet the 
specified minimum anchorage spacing requirement of 280 mm (11.0 in) 
simultaneously for all positions.
---------------------------------------------------------------------------

    \14\ This was based on our reading of M2K's petition, which was 
in a sparsely-worded bullet format. One bullet states: ``Spacing 
requirement only applies to fixed-anchorage seat belts, not sliding 
anchorages.'' (Emphasis in text.) No further discussion was provided 
by the petitioner.
---------------------------------------------------------------------------

d. Clarifications of Torso Anchorage Location

    Final Rule--NHTSA adopted requirements for the height of the torso 
belt anchorage to address the comfort of the torso (shoulder) belt and 
to ensure that the torso belt anchorage is not below the shoulder, 
which could result in compressive loads on the occupant's spine in a 
frontal crash. The final rule amended FMVSS No. 210 to require that the 
torso belt anchor point (where the torso belt first contacts the 
uppermost torso belt anchorage) be fixed or adjustable to at least 400 
mm (15.7 in) above the SgRP for a small occupant seating position of a 
flexible occupancy seat or at least 520 mm (20.5 in) above the SgRP for 
all other seating positions. (S4.1.3.2(a), FMVSS No. 210.)
    The final rule also required that the height of the torso belt be 
adjustable from the torso belt anchor point to within at least 280 mm 
(11 in) vertically above the seating reference point SgRP. Id. The 
height of the torso belt, as adjusted, is measured by determining the 
``school bus torso belt adjusted height'' as the term is defined in S3 
of FMVSS No. 210. ``School bus torso belt adjusted height'' was added 
to FMVSS No. 210 to provide an objective means of determining the 
height position of the adjusted torso belt. ``School bus torso belt 
adjusted height'' is defined in S3 as: the vertical height above the 
SgRP of the point at which the torso belt deviates more than 10 degrees 
from the horizontal plane when the torso belt is pulled away from the 
seat by a 20 N (4.5 lb) force at a location on the webbing 
approximately 100 mm (3.94 in) from the adjustment device and the 
pulled portion of the webbing is held in a horizontal plane.
    Petition for Reconsideration--In its petition for reconsideration, 
Blue Bird asked NHTSA to clarify the definition of ``school bus torso 
belt adjusted height,'' particularly with respect to the phrase 
``deviates more than 10 degrees from the horizontal plane.'' Blue Bird 
stated that it is not possible to pull the webbing in a horizontal 
plane and maintain the original point of belt contact because the arc 
of the belt forces load the application device downward since the lower 
anchor point is fixed.
    NHTSA's Response--The request is granted. We are clarifying the 
definition of ``school bus torso belt adjusted height'' and adding a 
new Figure 5 in FMVSS No. 210 to set forth in a clearer, more detailed 
manner how the torso belt adjusted height measurement will be made. The 
revised definition removes the confusing phrase ``deviates more than 10 
degrees from the horizontal plane'' and adds a new figure to indicate 
that the measurement is made to a horizontal segment of the torso belt 
that is located between 25 mm to 75 mm (1 in to 3 in) forward of the 
adjustment device while applying a horizontal 20 N (4.5 lb) force to 
the belt in the forward direction. The 20 N (4.5 lb) horizontal force 
is applied in the forward direction through the webbing at a location 
greater than 100 mm (3.94 in) forward of the adjustment device (as 
shown in the new Figure 5) after the retractor has been locked. Figure 
5 also illustrates that slack should remain in the portion of the belt 
between its bottom anchorage and the point of force application. This 
slack allows the upper portion of the torso belt, between the point of 
force application and the adjuster, to be pulled in a horizontal plane. 
We believe these amendments address the petitioner's concerns.

e. Integration of the Seat Belt Anchorages Into the Seat Structure

    Final Rule--The final rule specified that with the exception of the 
last row of seats, seat belt anchorages, both torso and lap, are 
required to be integrated into the seat structure. This requirement was 
established to prevent the incorporation of seat belt anchorages at 
locations that could result in belts potentially injuring unbelted 
school bus passengers in a crash or obstructing emergency egress.
    In the final rule, based on comments received on this issue, we 
excluded the last row of seats from the requirement because we 
concurred that the risk of injury or obstruction is lessened for this 
row of seats. The last row of seats in conventional large and small 
school buses typically has two seats with a 610 mm (24 in) aisle (large 
buses) or 559 mm (22 in) aisle (small buses) between them, to provide 
access to the rear emergency exit door. FMVSS No. 217 imposes 
requirements for unobstructed passage through the door. Thus, at least 
in the immediate vicinity of the door, we determined that FMVSS No. 217 
would prevent seat belts from being installed in such a way that could 
impede access to the emergency exit.\15\
---------------------------------------------------------------------------

    \15\ The requirement for a large school bus emergency exit door 
opening is found in 49 CFR 571.217 S5.4.2.1(a)(1).
---------------------------------------------------------------------------

    Petition for Reconsideration--In its petition for reconsideration, 
Blue Bird suggested that some ``last row'' seats should not be excluded 
from the requirement that the belts be integrated into the seat 
structure. The petitioner stated that some customers order buses with 
seat plans that have a wheelchair position located behind the rearmost 
passenger seat. In other cases, the rearmost passenger seat is forward 
enough that a side emergency door would be rearward of it. Blue Bird 
stated that in those cases, the rearmost passenger seat should have its 
seat belt

[[Page 66693]]

assembly anchorages attached to the seat structure to help prevent a 
trip hazard.
    NHTSA's Response--We have granted this aspect of the petition. We 
agree with the petitioner that seats with a wheelchair position or an 
emergency exit behind them should be required to have the seat belt 
anchorages integrated into the seat structure to help assure that the 
belts do not present a safety hazard for unrestrained passengers or 
during emergency evacuation, i.e., to reduce the risk of tripping, 
entanglement or injury. We have revised S4.1.3.1 to make the exclusion 
narrower and clearer.
    The final rule was ambiguous as to whether school bus seats that 
had a wheelchair position behind it comprised the last row of the 
school bus. Today's amendment makes S4.1.3.1 clear that seats in such a 
row are not excluded from the requirement for integral seat belts.

f. Seat Cushion Latches

    Final Rule--The final rule amended S5.1.5 of FMVSS No. 222 to 
require latching devices for school bus seats that have latches that 
allow them to flip up or be removed for easy cleaning. We also 
established a test procedure that would require the latch to activate 
when a 22 kg (48.4 lb) mass is placed on top of the seat at the seat 
cushion's center. The 22 kg (48.4 lb) mass is representative of the 
weight of an average 6-year-old child. The test procedure is to ensure 
that an unlatched seat cushion will latch when an average 6-year-old 
child sits on the seat.
    Petitions for Reconsideration--Marietta City School District (MCSD) 
of Ohio stated its belief that the requirement for self-latching seat 
cushions should be rescinded because the petitioner stated it presents 
a safety hazard or an ``accident waiting to happen.'' MCSD suggested 
that students will quickly learn to unlatch the seats and push them out 
of place, place obstructive items in the latch area, or unlatch them as 
a prank.
    M2K requested clarification of the test procedure for the seat 
cushion self-latching requirement specified in S5.1.5(a). It asked 
about the loading rate used to apply the 22 kg (48.4 lb) mass to the 
seat cushion, where on the seat cushion must the 22 kg (48.4 lb) mass 
be applied, and whether the 22 kg (48.4 lb) mass is a distributed load 
across the surface of the cushion or limited to a small percentage of 
the cushion area. Assuming the final rule is intended to ensure a 
child's weight alone will engage the latch mechanism, M2K suggested 
that a 213 mm x 305 mm (8.5 in x 12.2 in) rigid plate be used to 
``simulate the shape of a single 6-year-old'' child, and that the 
agency should ballast the plate to ensure an evenly-distributed 22 kg 
(48.4 lb) mass. The petitioner suggested that the plate should be 
oriented longitudinally above the centerline of the seat and then 
dropped horizontally onto the seat cushion from a height of 250 mm 
(9.84 in). The petitioner further suggested that ``NHTSA recommend the 
cushion latch mechanism make a distinct sound, similar to the `click' 
of a seat belt latching, when engaged.'' \16\
---------------------------------------------------------------------------

    \16\ M2K also recommended clarification of the test procedure 
for S5.1.5(b) of the seat cushion retention test. It stated that the 
method for testing the seat cushion is unclear and suggested 
clarification to the test procedure to allow, among other things, 
the load to be uniformly distributed across as much of the underside 
of the seat cushion as is practicable. M2K's suggestions are outside 
the scope of this rulemaking because changes to that test were not 
proposed in the NPRM. The procedure for performing the retention 
test has been in effect for over 30 years and school bus 
manufacturers are familiar with how the test is performed. The 
agency's compliance test procedure for the seat bottom cushion 
retention and self-latching tests are available on NHTSA's Web site 
at: https://www.nhtsa.dot.gov/staticfiles/DOT/NHTSA/Vehicle%20Safety/Test%20Procedures/Associated%20Files/TP222-04.pdf. The compliance 
test procedure for seat bottom cushion retention uses a force 
distribution pad of 102 mm radius between the load fixture and the 
cushion with a calibrated load cell between the seat cushion and 
load applicator. If it is not possible to use the distribution pad 
with 102 mm radius, a rectangular distribution pad of at least the 
same area is used to apply force to the seat cushion. An upward 
force equal to 5 times the weight of the seat cushion is applied in 
not less than 1 second or more than 5 seconds and maintained for 5 
seconds.
---------------------------------------------------------------------------

    In its petition for reconsideration, Blue Bird believed that the 
test load should be changed from ``22 kg (48.4 pound)'' to ``23.6 kg 
(52 pound).'' Blue Bird argued that no justification was provided for 
the 22 kg (48 lb) weight and the final rule (73 FR at 62760) stated 
that the Hybrid III 6-year-old child dummy weighed 52 lb (23.6 kg), so 
the test weight should be consistent with the Hybrid III 6-year-old 
dummy used in FMVSS No. 213, Child Restraint Systems.
    NHTSA's Response--We are denying the petitions except for a few of 
the requests of M2K. We start by noting that this rulemaking does not 
require that seat bottom cushions be designed to flip-up without the 
use of tools. However, such seat cushion designs are popular with many 
school systems and are widely available in school buses purchased 
today. MCSD may have misunderstood the final rule in this regard.
    We disagree with MCSD that requiring self-latching mechanism on 
seats designed to flip-up without the use of tools will result in a 
safety hazard. The agency proposed and implemented the requirement in 
the final rule because current seats can be left unlatched and, in the 
event of a rollover crash, the seat frames could become exposed and the 
bottoms could detach and become projectiles. The self-latching 
provision established in the final rule ensures that those flip-up 
seats have a self latching mechanism, and thus promotes safety. The 
requirement implements a National Transportation Safety Board 
Recommendation to NHTSA (H-84-75).
    To address M2K's suggestions about clarifying the test procedure 
for the self-latching seat requirement, this final rule makes minor 
revisions to the regulatory text so that the same tools and procedures 
can be used for the self latching test as those used for the seat 
retention test. We are changing the language to indicate a downward 
force, in Newtons (N), equivalent to the gravitational force exerted by 
a 22 kg mass (22 kg x 9.81 m/s\2\ = 216 N (48.4 lb)) that is currently 
specified to be placed on top of the center of the seat cushion be 
applied within 1 to 5 seconds and maintained for 5 seconds.\17\ We are 
also adding language clarifying that activation of the self-latching 
mechanism is assessed using the seat cushion retention test procedure 
and requirement.
---------------------------------------------------------------------------

    \17\ Some manufacturers suggested that the 22 kg mass be dropped 
from a specified height. We decline this suggestion because applying 
the force within 1 to 5 seconds is a simple and practical method of 
load application and is similar to the force application in the seat 
retention test.
---------------------------------------------------------------------------

    We disagree with M2K's suggestion that the agency recommend that 
seat latch mechanisms make a distinct sound, similar to the ``click'' 
of seat belt latching, when engaged. We have no requirements in FMVSS 
No. 209, ``Seat belt assemblies,'' requiring that the seat belt 
latching mechanism make an audible ``click'' sound when engaged. 
However, manufacturers have voluntarily included this feature for seat 
belt systems. We are not persuaded that requiring or recommending that 
the seat cushion self-latching mechanism make an audible sound when 
engaged is necessary. Manufacturers may include such features if there 
is a consumer demand for it.
    We disagree with Blue Bird's statement that no justification was 
provided for the 22 kg (48.4 lb) weight and with Blue Bird's suggestion 
that the test load be changed from ``22 kg (48.4 pounds)'' to ``23.6 kg 
(52 pounds)'' to be consistent with the Hybrid III 6-year-old dummy in 
FMVSS No. 213. The NPRM and the final rule both indicated that the 22 
kg (48.4 lb) mass was used to simulate the weight of an average 6-

[[Page 66694]]

year-old child.18 19 In the October 21, 2008 final rule, at 
S7.1.4 of FMVSS No. 208, we included anthropometric data to indicate 
that the weight of a 50th-percentile 6-year-old child is 21.4 kg (47.3 
lb). Thus, the agency used a 22 kg (48.4 lb) mass in the test and 
sufficient reasoning was provided in the NPRM and final rule. 
Furthermore, we are unconvinced that it is more desirable for the 
weight used in the test to match the weight of the Hybrid III 6-year-
old dummy rather than the weight of an average 6-year-old child.
---------------------------------------------------------------------------

    \18\ 72 FR 65515, school bus NPRM.
    \19\ 73 FR 62756, school bus final rule.
---------------------------------------------------------------------------

IV. Comments on Decisions Not Involving Regulatory Text

a. Requiring Large School Buses To Have Seat Belts

    Final rule--In the final rule, we specified performance 
requirements for voluntarily-installed lap and lap/shoulder belts in 
large school buses to ensure both the strength of the anchorages and 
the compatibility of the seat with compartmentalization. We could not 
find a safety need to require passenger seat belt systems on large 
school buses to supplement the protection provided by 
compartmentalization.
    Post Final Rule Comments--In a document styled as a petition for 
reconsideration, Public Citizen (PC) objected to the final rule's not 
requiring lap/shoulder passenger seat belts in new large school 
buses.\20\ PC made several comments related to this issue.
---------------------------------------------------------------------------

    \20\ The NPRM did not propose to require passenger seat belts on 
large school buses. The NPRM discussed NHTSA's reasons for deciding 
not to propose passenger seat belts on large school buses.
---------------------------------------------------------------------------

    1. PC asked the agency to revise its analysis of the potential 
benefits of lap/shoulder belts on large buses ``to include updated 
analysis of multiple crash modes including side-impact and rollover. * 
* *'' PC stated that NHTSA ``must provide a more credible explanation 
of its determination of restraint performance in these other crash 
modes than the correlation to passenger cars.''
    2. PC objected to the following NPRM statement regarding NHTSA's 
best practices: ``If ample funds were available for pupil 
transportation, and pupil transportation providers could order and 
purchase a sufficient number of school buses needed to provide school 
bus transportation to all children, pupil transportation providers 
should consider installing lap/shoulder belts on large school buses.'' 
The petitioner stated that this ``undermines the safest option for 
children on these buses rather than either refusing or encouraging lap/
shoulder belt installation.''
    3. PC stated that it agrees with the National Transportation Safety 
Board (NTSB) comment that lap-only belts should not be permitted. PC 
stated that in 1999 the NTSB suggested there may be potential for 
greater injuries in occupants restrained using lap-only belts in side 
crashes. Further, PC stated that we have not discussed how raising the 
seat back height affects the performance of lap-only belts.
    4. PC stated that NHTSA ``does not discuss the effect of `economies 
of scale' in reducing the incremental cost of adding belts to the buses 
* * *. Economies of scale and learning by doing can significantly 
reduce costs, but NHTSA's economic analyses makes no mention of these 
effects.''
    NHTSA's Response--The important public policy issue of whether to 
require the installation of seat belts for school bus passengers is 
before the agency in petitions for rulemaking submitted by the Center 
for Auto Safety, PC and a wide variety of school bus safety and medical 
organizations and associations. The agency will consider PC's comments 
in responding to those petitions.

b. Defining a ``Small'' School Bus

    Final Rule--In the final rule, NHTSA declined the suggestions of 
some commenters to raise the gross vehicle weight rating (GVWR) 
delineation between ``small'' and ``large'' school buses from 4,536 kg 
(10,000 lb) to 6,576 kg (14,500 lb).\21\ The agency believed that the 
suggestion was beyond the scope of the rulemaking.
---------------------------------------------------------------------------

    \21\ Commenters sought to subject ``Type A-2'' school buses, 
which have a GVWR that can range up to 6,576 kg (14,500 pounds), to 
the requirements for small school buses.
---------------------------------------------------------------------------

    In administering NHTSA's school bus safety standards, the agency 
has historically used GVWR to determine the applicability of the FMVSS 
requirements and has historically used a GVWR of 4,536 kg (10,000 lb) 
to classify school buses. ``Small'' school buses (GVWR of 4,536 kg 
(10,000 lb) or less) have been required to have passenger seat belts 
while large school buses (GVWR above 4,536 kg (10,000 lb)) have not. 
The NPRM presented the agency's crash and sled test data relating to 
small and large school buses and discussed different views on the 
merits of having seat belts on small and large school buses. Nowhere in 
the NPRM was there a discussion about reclassifying some large school 
buses as small school buses or raising the 4,536 kg (10,000 lb) GVWR 
delineation. Nowhere in the NPRM was it proposed to require passenger 
seat belt systems in buses that are not currently required to have 
passenger seat belts, nor was it suggested that those buses should be 
subject to the other school bus safety standards applicable to small 
school buses.
    Because the NPRM did not discuss the possibility of requiring 
passenger belt systems in buses between 4,536 kg (10,000 lb) and 6,576 
kg (14,500 lb), NHTSA believed that raising the GVWR delineation to 
6,576 kg (14,500 lb) and thus subjecting school buses with a GVWR 
between 4,536 kg (10,000 lb) and 6,576 kg (14,500 lb) to a new set of 
FMVSS requirements would be beyond the scope of the rulemaking. The 
agency thus declined to raise the GVWR cut-off in the final rule. We 
noted that the suggested change