[Federal Register Volume 63, Number 77 (Wednesday, April 22, 1998)]
[Rules and Regulations]
[Pages 19839-19842]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-10674]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Parts 571 and 589
[Docket No. NHTSA-98-3421]
RIN 2127-AB85
Federal Motor Vehicle Safety Standards; Head Impact Protection
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation.
ACTION: Denial of petitions for reconsideration.
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SUMMARY: This document denies petitions for reconsideration submitted
by the American Automobile Manufacturers Association (AAMA) and ASC,
Incorporated (ASC). On April 8, 1997, NHTSA published a final rule
amending provisions in Standard No. 201, Head Impact Protection,
relating to upper interior head impact protection. The amendments
revised and clarified test procedures, added an optional compliance
phase-in plan, allowed carry-forward credits to facilitate compliance,
and excluded small buses from the Standard's upper interior impact
protection requirements. ASC's petition stated the company's concerns
about the impact of the final rule on the integrated convertible roof
and frame designs and requested a further amendment to the definition
of ``convertible roof frame system.'' AAMA's petition requested that
NHTSA reconsider and modify the final rule in reference to approach
angles, moveable side glazing, multiple impacts, the procedure for
locating CG-F (a reference point corresponding to the location of a
front seat occupant's head), and the definition of ``forehead impact
zone.''
DATES: Petition Date: Any petitions for reconsideration of this denial
must be received by NHTSA no later than June 8, 1998.
ADDRESSES: Any petitions for reconsideration should refer to the docket
and notice number of this notice and be submitted to: Administrator,
National Highway Traffic Safety Administration, 400 Seventh Street, SW,
Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: For legal issues: Mr. Otto Matheke,
Office of the Chief Counsel, NHTSA, 400 Seventh Street, SW, Washington,
DC 20590. Mr. Matheke's telephone number is (202) 366-5253. His
facsimile number is (202) 366-3820. For non-legal issues: Dr. William
Fan, Office of Crashworthiness Standards, NPS-11, Dr. Fan's telephone
[[Page 19840]]
number is (202) 366-4922. His facsimile number is (202) 366-4329.
SUPPLEMENTARY INFORMATION: On August 18, 1995, the National Highway
Traffic Safety Administration (NHTSA) published a final rule (60 FR
43031--Docket No. 92-28; Notice 4) amending Federal Motor Vehicle
Safety Standard (FMVSS) No. 201, ``Occupant Protection in Interior
Impact,'' to require passenger cars, trucks, buses, and multipurpose
passenger vehicles (MPVs) with a gross vehicle weight rating (GVWR) of
4,536 kilograms (10,000 pounds) or less to provide head protection
during a vehicle crash when the occupant's head strikes pillars, side
rails, headers, or the roof of the vehicle. The final rule specifies a
24 km/h (15 mph) in-vehicle component impact test that uses a free-
motion headform (FMH). The injury criterion is the HIC limit of 1,000.
The effective date is a four-year phase-in plan (10 percent, 24
percent, 40 percent, 70 percent and 100 percent) beginning on September
1, 1998. An optional implementation plan is a one-year phase-in plan (0
percent and 100 percent) beginning on September 1, 1998. A final stage
manufacturer or alterer must comply with the standard's upper interior
impact requirements for vehicles manufactured on or after September 1,
2002.
The agency received ten petitions for reconsideration in response
to the August 1995 final rule. In response to those petitions, NHTSA
published another final rule on April 8, 1997 (62 FR 16718--Docket No.
92-28; Notice 7) revising test procedures, adding an optional phase-in
plan, allowing carry-forward credits, and excluding small buses from
the upper interior head impact requirements. In addition, NHTSA
initiated a new rulemaking concerning alternative procedures for
testing dynamically deployed head protection systems.
In response to the April 1997 final rule, the American Automobile
Manufacturers Association (AAMA) and ASC, Incorporated submitted new
petitions for reconsideration. The ASC petition requested exclusion of
the convertible top from the FMH impact requirements, while the AAMA
petition addressed technical issues in general areas.
The ASC Petition for Reconsideration
On May 22, 1997, ASC submitted a petition for reconsideration
arguing that the amendments to the August 1995 final rule did not
address current convertible top designs that include integrated roof
and frame systems (e.g., a removable hardtop). ASC also indicated its
belief that the addition of padding to an integrated convertible roof
and frame system would prevent the roof from folding into the available
storage area below the beltline or in the rear storage area, thereby
interfering with rear vision or requiring elimination of the rear seat
in some models. Compliance with Standard No. 201's upper interior
impact requirements would, in ASC's view, limit future design and
development of convertible tops to traditional vinyl or canvas top
convertibles with separate frames. As a result, production and sale of
more ``advanced'' integrated convertible top designs would become
impracticable. Accordingly, in its petition for reconsideration, ASC
requested that the convertible roof frame definition in the amended
final rule be revised to read as follows:
Convertible roof frame means the frame of a convertible roof and
the roof and frame of a convertible with an integrated roof and
frame system which is capable of folding and being stored below the
beltline or in the rear storage compartment of the vehicle.
Without this revision, ASC believes that the automobile industry will
not be able to continue production and development of new convertible
automobile designs with integrated roof and frame systems.
The agency notes that the exclusion of convertible roofs and
linkages is an issue that was examined extensively throughout the
rulemaking process leading up to the August 1995 and April 1997 final
rules. In the August 1995 final rule, NHTSA agreed to exclude
``convertible roof frames and linkage mechanisms because the presence
of a countermeasure such as padding would interfere with their
movement'' (60 FR 43031, at 43047). The April 1997 final rule, issued
in response to petitions for reconsideration filed after the issuance
of the August 1995 final rule, deleted the word ``metal'' from the
definition of ``convertible roof frame'' in response to objections that
limiting excluded frames to those made of metal was design restrictive
(62 FR 16718, 16721).
ASC's request for reconsideration raises an issue that NHTSA
examined prior to the issuance of the August 1995 final rule and the
April 1997 final rule. In the preamble to the April 1997 final rule,
the agency observed that commenters did not provide any support for the
claim that countermeasures could not be installed on areas other than
convertible roof frames and linkage mechanisms. NHTSA further stated
that rigid convertible tops could produce head injuries and that the
agency believed that protection should be provided for all the hard
areas inside a vehicle unless it is not practicable to do so. The ASC
petition does not include any new data or information demonstrating
either that the agency's prior decision not to exclude convertible
roofs was wrong or that newer roof designs require reconsideration of
the issue.
In the absence of new data, the agency considered the ASC petition
based on the agency's current knowledge of vehicle roof designs. The
upper roof area of a typical passenger car is relatively soft in
comparison with the pillar and side rail components of the vehicle.
Based on the agency's current knowledge, the upper roof structure of a
typical production car does not require any padding to comply with the
FMH impact requirements. The roof structure is basically a shallow,
thin shell design with some rib-type reinforcement members (roof cross-
member and/or roof bow member). A properly designed thin shell
structure is a very effective energy absorptive design. A roof
structure made of sheet metal or other flexible materials should be
able to meet Standard 201's requirements without the extensive use of
padding or other countermeasures. ASC has not submitted any data
indicating that convertible hardtops cannot be made as flexible as a
conventional roof structure. NHTSA believes that there is not a
sufficient basis for treating convertible hardtops differently from
regular vehicle roof structures and that convertible hardtops should be
subject to Standard No. 201's upper interior impact requirements.
Agency test data indicate that the upper roof of many production
cars can comply with those requirements without any modification. An
integrated convertible roof, except frames and linkage mechanisms, is
basically a shallow thin shell design that is soft and smooth. Since
convertible roof frames and linkage mechanisms are excluded from the
final rule, the design of the remainder of the convertible hardtop roof
should not present additional compliance difficulties. The agency
believes that integrated convertible roof designs should be able to
meet Standard 201 when the roof top membrane structure is tested using
the FMH impactor at a speed up to 24 km/h (15 mph). Since ASC has not
demonstrated that a ``hard'' convertible top that meets Standard 201's
upper interior impact requirements cannot be built or is otherwise
impracticable, the agency is denying ASC's petition.
[[Page 19841]]
The AAMA Petition for Reconsideration
On May 23, 1997, AAMA submitted a petition for reconsideration
requesting that NHTSA consider additional changes to Standard No. 201
to address concerns relating to approach angles in compliance testing,
hinged and moveable glazing, multiple FMH impacts, the procedure for
locating a reference point that corresponds to the head position of a
front seat occupant and is known as CG-F, and the definition of the
forehead impact zone of the FMH.
In defining the trajectory of the FMH when it is propelled at
target points located on all pillars except the A-pillar, the April
1997 final rule specified a vertical approach angle range for the FMH
of +50 to -10 degrees. AAMA believes that the minimum vertical angle of
-10 degrees may not be sufficient to allow the FMH to make proper
contact with certain targets. In AAMA's view, simultaneous contact of
the forehead and chin may occur when the pillar surface on which the
target is located is canted (from top to bottom) toward the inside of
the vehicle at an angle of approximately 10 degrees. AAMA recommended
that the existing target exclusion in S6.1 be expanded so that targets
that cannot be tested using the approach angle limits specified in
S8.13.4 would be excluded from the upper interior impact requirements.
NHTSA does not believe that the exclusion in S6.1 must be modified
to address AAMA's concern. As it appears in the April 1997 final rule,
S6.1 indicates that the FMH impact requirements do not apply to any
target that cannot be located using the procedure of S10. S10(b)
specifies that, except as specified in S10(c), if there is no
combination of horizontal and/or vertical approach angles specified in
S8.13.4 at which the forehead impact zone of the FMH can contact one of
the targets located using the procedures in S10.1 through S10.13, the
center of that target is moved to any location within a 25 mm sphere,
centered on the center of the original target and measured along the
vehicle interior, that the forehead impact zone can contact at one or
more combination of angles. S10(c) specifies that if there is no point
within the sphere specified in S10(b) which the forehead of the FMH can
contact at one or more combination of horizontal and/or vertical
approach angles specified in S8.13.4, the sphere is increased by
25 mm increments until it contains at least one point that can be
contacted at one or more combination of angles. In addition, S8.13.4.2
specifies procedures for determining vertical approach angles that
would avoid simultaneous contact of the forehead and chin. If a
specific target cannot be tested using the approach angle limits
specified in S8.13.4, the target should be relocated using S10(b) or
S10(c). Accordingly, NHTSA concludes that an amendment to the final
rule is not necessary to resolve AAMA's concern.
As noted above, the April 1997 final rule excluded convertible roof
frames and linkage mechanisms from Standard No. 201's upper interior
impact requirements. AAMA's petition for reconsideration requested that
the hinge and latch components for sunroofs and moveable side glazing
be accorded similar treatment. The organization argued that these
components, like convertible roof frames and linkage mechanisms, cannot
function if they must be padded to meet Standard No. 201.
NHTSA does not believe that the same considerations that apply to
convertible roof frames and linkage mechanisms also apply to sunroof
and side window latches and hinges. First, convertible roofs are large
and complex compared to sunroofs and moveable glazing, and therefore
require much stronger latches and anchorages to stabilize the whole
roof during high speed travel. Second, the size and complexity of
convertible roof mechanisms are such that padding those components may
interfere with the operation of the convertible roof top. In contrast,
the latches and hinges used in the sunroofs and moveable glazing of
current production vehicles are usually small in size and made of, or
enclosed with, plastic materials. Although the amended final rule does
not identify the latches or hinges of moveable side glazing or sunroofs
as targets for compliance testing, these components could be located in
target areas. However, the agency believes that padding these
fasteners, if required, would not significantly affect the operation of
sunroofs and side windows. NHTSA also notes that similar components,
such as safety belt anchorages and grab handles, may also have to be
padded. The agency is not aware of any justification for
differentiating between the latter and sunroof or side window hinges
and latches.
The April 1997 final rule specified that a FMH impact may not occur
within 150 mm distance of any prior FMH impact. AAMA believes that the
minimum distance of 150 mm is not adequate to address complex impact
conditions. The organization contends that the type of countermeasure,
the target location, the size of target component, the impact approach
angles, and the interaction of chin loading are factors that may lead
to multiple impacts affecting test results. Since damage to trim as a
result of an impact cannot be readily detected through visual
observation and manufacturers cannot reliably anticipate the effects on
material or component performance, AAMA contends that only one impact
be allowed for each component.
The agency does not agree. In order to complete vehicle compliance
tests with one vehicle, NHTSA concluded in the final rule that multiple
FMH impacts on a component should be allowed, that impacts on both left
and right side components should be allowed, but that an overlap of two
FMH impacts should not be allowed. The agency determined that the
minimum distance between two targets should be 150 mm (6 inches). In
order to allow padding to recover from a FMH impact, a 30-minute
waiting period is specified if the next impact is to be on the same
component.
NHTSA believes that the existing minimum distance between impact
points is adequate. The maximum width of the Hybrid III headform is 150
mm and the effective width of the forehead impact zone is much less
than 150 mm. With two adjacent targets at 150 mm distance, overlapping
of the FMH contact should not occur. The agency also believes that
manufacturers may test in a fashion that minimizes multiple impacts.
The amended final rule allows testing of both left and right side
components; multiple impacts would generally occur during the A or B-
pillar component tests. If target selection is made using both side
components, the actual distance between two adjacent targets could be
much larger than the specified minimum distance of 150 mm. In addition,
NHTSA testing indicates that the foam damage area from an impact is
smaller than the forehead impact zone.
AAMA also argued that only one FMH impact should be allowed for
each component due to the uncertainty involved in choosing a design
and/or material for compliance testing. NHTSA notes that AAMA has
raised this issue in a previous petition for reconsideration. In that
instance, AAMA did not submit any test data establishing that
permitting only a single test for each component is necessary or
desirable. In its current request, AAMA has not submitted any new test
data supporting such a contention. NHTSA has previously declined to
adopt a limitation on the number of impacts per component and declines
to do so now.
[[Page 19842]]
The agency also wishes to make it clear that where Standard 201, or
other Federal motor vehicle safety standards, do not address a specific
test condition, vehicles must comply in all circumstances consistent
with anticipated use of the vehicle by occupants. Multiple impacts to
one component are an example of a circumstance that might be
encountered in a crash. NHTSA may therefore test single components with
multiple impacts when performing compliance testing under Standard 201.
The AAMA petition also requests that the agency rectify an apparent
conflict involving the procedure for locating CG-F by use of the
``seating reference point (SgRP).'' The SgRP is a single point which
establishes the rearmost normal design driving or riding position. In
Standard No. 201, S8.12(a)(1) uses SgRP with the seat in its rearmost
normal design or driving position to locate the rearmost CG-F (CG-F2).
The forwardmost CG-F (CG-F1) is, according to S8.12(a)(2), located
horizontally forward of CG-F2 by the distance equal to the fore and aft
distance of the seat track. Because S8.12(a)(2) describes CG-F1 as the
head center of gravity with the seat in its forwardmost adjustment
position, AAMA believes that S8.12 implies that the reference point to
be used is not SgRP, which is a single point, but rather the design H-
point, which can occupy a number of points according to the seat
adjustment. In its petition, AAMA suggested that a conflict existed and
requested that it be resolved.
When the August 1995 final rule was published, NHTSA was requested
to change the reference point from the SgRP to the H-point. The agency
explained in the preamble of the April 1997 final rule that a change of
the reference point is not necessary. This is because the only point
used for locating CG-F1 and CG-F2 is the single SgRP. The agency notes
that, prior to a recent correcting amendment published on January 2,
1998 (63 FR 27), S8.12(a)(1) incorrectly specified that C--F2 should be
located with the seat in its rearmost adjustment position rather than
the rearmost normal design driving or riding position. As the SgRP only
exists in the latter position and not the former, AAMA and others could
have reasonably concluded that NHTSA intended that the design H-point
rather than the SgRP be used to locate CG-F1 and CG-F2. The reference
in S8.12(a)(2) to the seat being in its forwardmost adjustment position
to assist in describing CG-F1 may have created further opportunities
for misunderstanding. However, the agency believes that the correcting
amendment to S8.12(a)(1) resolved this issue and that further
rulemaking is not required.
AAMA also suggested that the existing definition of the forehead
impact zone is in error. In its petition, AAMA recommended that in
S8.10(d), the word ``vertical'' be replaced with ``horizontal'' as it
refers to a plane along the contour of the outer skin of the forehead
of the FMH. S8.10(d) specifies the procedure for locating the upper
boundary of the forehead impact zone by directing that a line be drawn
along the contour of the headform and through a point on a vertical
line in the midsagittal plane of the FMH so that the line is bisected
by that point. This line is described as being coincident to a vertical
plane, while the procedure for locating the lower horizontal boundary,
found in S8.10(c), specifies that the lower boundary line be coincident
to a horizontal plane. AAMA's belief that the use of the vertical plane
in S8.10(d) is in error may be premised on the use of the horizontal
plane in S8.10(c) for locating a similar line. However, at the point
where the upper boundary of the forehead impact zone is located, the
contours of the FMH are such that the use of a horizontal plane for
locating the upper boundary would result in the forehead impact zone
extending along the sides of the FMH. NHTSA has determined that the use
of a vertical plane in describing this procedure is more appropriate.
Use of a horizontal plane to describe the forehead impact zone would
include part of the side of the head in the forehead impact zone.
Based on the foregoing, NHTSA denies the AAMA and ASC petitions.
Authority: 49 U.S.C. 30103, 30162; delegation of authority at 49
CFR 1.50 and 501.8.
Issued on: April 10, 1998.
Ricardo Martinez,
Administrator .
[FR Doc. 98-10674 Filed 4-21-98; 8:45 am]
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