[Federal Register Volume 61, Number 187 (Wednesday, September 25, 1996)]
[Proposed Rules]
[Pages 50268-50269]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-24513]
[[Page 50268]]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
Denial of Petition for Rulemaking; Federal Motor Vehicle Safety
Standards
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation.
ACTION: Denial of petition for rulemaking.
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SUMMARY: This document denies Thomas Built Buses, Inc., petition to
change the head protection zone requirements in FMVSS No. 222. Thomas
stated in the petition that it felt that the head protection zones
referenced in S5.3.1.1 were defined by NHTSA with a square school bus
body in mind. Thomas requested that S5.3.1.1(c) be changed to allow for
differences in design.
NHTSA is denying this petition. Thomas offered no justification for
changing the standard other than that they perceived that the standard
was developed with a square school bus body in mind. The history of
FMVSS No. 222 clearly indicates that the head protection zones were
established with the bus occupant's head in mind and not the bus body
as Thomas believes. In fact the statement in S5.3.1.1 that ``The head
protection zones in front of each school bus seat which are not
occupied by the bus sidewall, window, or door structure * * *''
indicates that the standard specifically considered the possibility of
non-square bus bodies. Changing the standard, as proposed in the Thomas
petition, would allow manufacturers to install unpadded objects in
locations where the bus occupant's head is likely to come in contact
with them in a frontal collision.
FOR FURTHER INFORMATION CONTACT: Charles Hott, Office of
Crashworthiness Standards, NPS-12, NHTSA, 400 7th Street, SW,
Washington, DC 20590 (telephone 202-366-0247, Fax: 202-366-4329).
SUPPLEMENTARY INFORMATION: Thomas Built Buses, Inc., petitioned the
agency to change the head protection zone requirements in FMVSS No.
222, S5.3.1.1. Thomas stated that it felt that the zones referenced in
S5.3.1.1 were defined by NHTSA with a square school bus body in mind.
Thomas also stated that its school bus body design has a 2.25 degree
inward taper from the beltline of the bus upward to the point where the
bus sidewall ends. Thomas stated that over the 28 inch span of head
protection zone, the taper reduces the 3.25 inch dimension referenced
in S5.3.1.1(c) to approximately 2.25 inches on the interior of the bus
sidewall. Thomas requested that S5.3.1.1(c) be changed to allow for
differences in design. Thomas stated that this change will not affect
the impact testing required by S5.3.1.2 and it will still meet the
intent of the standard. Thomas requested that the wording in
S5.3.1.1(c) be changed to the following:
S5.3.1.1(c) A longitudinal plane 3.25 inches inboard of and
parallel to the bus sidewall, window, or door structure. FMVSS No 222;
HEAD PROTECTION ZONE REQUIREMENTS: The head protection zone
requirements are specified in S5.3.1 of the standard and are as
follows:
S5.3.1 Head protection zone. Any contactable surface of the
vehicle within any zone specified in S5.3.1.1 shall meet the
requirements of S5.3.1.2 and S5.3.1.3. However, a surface area that has
been contacted pursuant to an impact test need not meet further
requirements contained in S5.3.
S5.3.1.1 The head protection zones in each vehicle are the spaces
in front of each school bus passenger seat, which are not occupied by
the bus sidewall, window, or door structure and which, in relation to
that seat and its seating reference point, are enclosed by the
following:
(a) Horizontal planes 12 inches and 40 inches above the seating
reference point;
(b) A vertical longitudinal plane tangent to the inboard (aisle
side) edge of the seat;
(c) A vertical longitudinal plane 3.25 inches inboard of the
outboard edge of the seat, and
(d) Vertical transverse planes through and 30 inches forward of the
reference point.
S5.3.1.2 specifies the head form requirement and
S5.3.1.3 specifies the head form force distribution requirement.
The history of rulemaking on FMVSS No. 222 shows that the head
impact zone requirements of the standard go back to the original
proposal published February 22, 1973. In that proposal the agency
stated:
``To eliminate the exposed metal bars and similar designs and to
make the seat itself a significant energy absorber, the NHTSA proposes
to require all surfaces within a specified area ahead of the seat to
meet a head impact criterion similar to the one included in Standard
208, occupant crash protection. * * * Most types of metal surface would
be too hard and would therefore not meet the requirements of the
proposed standard.''
In a subsequent proposal dated July 30, 1974, the agency stated the
following:
``The proposal again specifies two zones in which impact by a head
form or knee form must conform to specified force distribution and
certain force or acceleration levels. The head protection zone is
somewhat smaller than earlier proposed to accommodate tumble-home
construction in side windows. * * *
These zones and many of the other requirements are based on
location of the seating reference point, * * * The definition also
specifies that the point have coordinates established relative to the
designed vehicle structure, to permit the point to be located with
certainty for enforcement purposes. * * * Because of the particular
seat installation methods used in school buses, NHTSA would interpret
``designed vehicle structure'' to include the seat structure itself as
mounted in the bus. The bus designer would therefore be able to specify
the point coordinates from the seat structure alone.''
In yet another subsequent proposal dated October 8, 1975, the
agency stated the following:
``The NHTSA has carefully calculated its impact requirements to
reflect the fact that a crash from any direction can cause the occupant
to impact any part of the adjacent seats or protruding objects from any
direction.''
Standard No. 222 defines contactable surface as follows:
Contactable Surface is defined as any surface within the zone
specified in S5.3.1.1 that is contactable from any direction by the
test device described in the standard, except any surface on the front
of a seat back or restraining barrier 3 inches or more below the top of
the seat back or restraining barrier.
The final rule was published January 28, 1976. As a result of a
petition for reconsideration from Sheller Globe Corporation, the agency
modified the head protection zone requirements in the standard so that
the bus body side panels, window or door structure would not be
considered part of the head protection zone. This was modified because
the construction of some buses allowed those elements of the bus body
to be in the head protection zone. In allowing this change the agency
stated:
``As Sheller noted, the agency has never intended to include the
body side panels and glazing in the protection zone. The roof structure
and overhead projections from the interior are included in this area of
the zone.''
[[Page 50269]]
From May 1977 until September 1981, NHTSA made at least four
interpretations pertaining to the head protection zone requirement in
the standard that show the bus sidewall extending in the head
protection zone specified in the standard. Those interpretations dealt
mainly with where the sidewall ends and the roof structure begins. Roof
structures are required to meet the contactable surface requirements if
they fall within the head protection zone. None of the manufacturers,
Mid Bus, Collins, Coach and Equipment, and The Coachette Company,
questioned whether the intent of the standard was based on a square bus
body.
While there is no reason specified in the early rulemakings for the
3.25 inch dimension from the outboard edge of the school bus seat,
NHTSA believes that this was considered to be a limitation caused by
the size of the head form used for impact testing. The head form has a
radius of 3.25 inches. Thus, there would be a 3.25 inch area from 12
inches above the seating reference point to the top of the seat back
where the head form could not impact.
As can be seen by the history of the rulemaking, the head
protection zones were included to prevent manufacturers from installing
objects that the bus occupant's head may come in contact with during a
collision. Those objects included the seat backs, luggage racks, and
other items that were sometimes placed above the seats on the pre-
standard school buses.
Thomas' assertion that changing the standard would not affect the
impact testing requirement of the standard is incorrect. In fact,
changing the head protection zone specified in S5.3.1.1(c) to a
longitudinal plane 3.25 inches inboard of and parallel to the bus
sidewall, window, or door structure would allow manufacturers to place
objects that protrude outward from the bus body side panels 3.25 inches
in an area that a school bus occupant's head is likely to strike if the
bus is involved in a collision. These items would not have to meet the
requirements for contactable surfaces and therefore would increase the
potential for head injuries during a collision. Thomas offered no
justification for changing the standard other than that they perceived
that the standard was developed with a square school bus body in mind.
The history of FMVSS No. 222 clearly indicates that the head protection
zones were established with the bus occupant's head in mind and not the
bus body as Thomas stated.
In accordance with 40 CFR part 552, this completes the agency's
review of the petition. The agency has concluded that there is no
reasonable possibility that the specified action requested by the
petitioner would be issued at the conclusion of a rulemaking
proceeding. Accordingly, it denies the Thomas Built Buses, Inc.
petition.
Authority: 49 U.S.C. 30103, 30162; delegation of authority at 49
CFR 1.50 and 501.8.
Issued: September 19, 1996.
L. Robert Shelton,
Acting Associate Administrator for Safety Performance Standards.
[FR Doc. 96-24513 Filed 9-24-96; 8:45 am]
BILLING CODE 4910-59-P
