[Federal Register Volume 61, Number 186 (Tuesday, September 24, 1996)]
[Proposed Rules]
[Pages 49992-49998]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-24206]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Parts 571 and 572
[Docket No. 96-098, Notice 01]
RIN 2127-AG37
Side Impact Protection Side Impact Dummy
AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT.
ACTION: Notice of proposed rulemaking.
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SUMMARY: This document proposes two amendments to the specifications
for the side impact test dummy and to the procedure in NHTSA's side
impact protection standard for positioning the dummy in a vehicle for
compliance testing purposes. The first amendment would add plastic
inserts-spacers to the dummy's lumbar spine. This change is intended to
prevent a cable within the spine from snapping, which some
manufacturers believe can generate large spikes in the data obtained
from the dummy. The second amendment would specify that the ribcage
damper piston of the dummy is set during the dummy positioning
procedure to the fully extended position prior to the side impact
dynamic test. These changes are intended to improve the consistency of
the data obtained from the dummy in a side impact crash test.
DATES: Comments on this proposed rule must be received by the agency no
later than November 25, 1996.
Proposed effective date: 45 days after publication of a final rule
in the Federal Register.
ADDRESSES: Comments should refer to the docket number and notice number
and be submitted in writing to: Docket Section, National Highway
Traffic Safety Administration, Room 5109, 400 Seventh Street, S.W.,
Washington, D.C., 20590. Telephone: (202) 366-5267. Docket hours are
9:30 a.m. to 4:00 p.m. Monday through Friday.
FOR FURTHER INFORMATION CONTACT: For nonlegal issues: Mr. Stan
Backaitis, Office of Vehicle Safety Standards, (telephone 202-366-
4912). For legal issues: Ms. Deirdre Fujita, Office of the Chief
Counsel (202-366-2992). Both can be reached at the National Highway
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Traffic Safety Administration, 400 Seventh St., S.W., Washington, D.C.,
20590.
SUPPLEMENTARY INFORMATION:
Background
On October 30, 1990, NHTSA published a rule that established
dynamic side impact protection requirements for passenger cars. (See,
final rule amending Federal Motor Vehicle Safety Standard No. 214, Side
Impact Protection, 49 CFR 571.214; 55 FR 45722.) The requirements,
which became effective September 1, 1993, improve safety by providing
protection against injuries to an occupant's thorax and pelvis in a
side impact crash.
The requirements provide this protection by placing a side impact
dummy (SID) in a vehicle, subjecting the vehicle to a side impact crash
test and limiting the amounts of force measured by accelerometer
sensors mounted in the thorax and pelvis of the SID. The SID represents
an adult male 50th percentile size occupant. At the time of the
amendment to Standard 214, specifications for the SID were added to
NHTSA's test dummy regulation (see, 49 CFR part 572, subpart F).
Four accelerometers are used to measure the crash test forces.
Three accelerometers are mounted in the dummy's thorax and provide
acceleration values used in determining the ``Thoracic Trauma Index
(TTI(d)).'' TTI(d) is an injury criterion that measures the risk of
thoracic injury of a passenger car occupant in a side impact. The
fourth accelerometer, mounted in the pelvic cavity, measures the
potential risk for pelvic injury. To meet Standard 214's side impact
protection requirements, the TTI(d) and pelvic measurements must be
below specified maximum values.
Lumbar Spine Inserts
The lumbar spine of the SID is a molded hollow cylindrical rubber
element, with bonded circular metal plates that have a hole in the
center at each end. A metal cable passes through the center of the
lumbar spine cylinder. The top end of the cable is threaded, and the
bottom end is shaped like a ball. The threaded end of the cable is
fastened with a nut, which can be tightened to provide the desired
compression in the lumbar.
A number of motor vehicle manufacturers have informed NHTSA that
they have observed spikes in data obtained from side impact tests that
increase the variability and the magnitude of the TTI(d). The American
Automobile Manufacturers Association (AAMA), representing Ford,
Chrysler Corporation and General Motors Corporation, raised the issue
of these spikes in a June 29, 1994 letter to the agency. AAMA said that
metal-to-metal contact in the SID lumbar spine--
is inducing data spikes that are of long enough time duration to
become part of the data when it is filtered according to the
requirements of Standard No. 214. Inclusion of these data spikes in
the data increases variability and unwarrranted higher calculations
of TTI(d). The spikes could cause manufacturers to redesign their
vehicles for no safety reason other than an artifact of the SID.
This redesign would increase business costs with no safety benefit
to the customer.
AAMA stated that it determined that the noise spikes were caused by
(1) the nut and threaded area on top of the metal spine cable striking
the inner edge of the hole of the metal top-plate of the lumbar spine
when the spine flexes; (2) the ball at the end of the lumbar spine
cable popping in and out of the seat of the metal bottom plate when the
spine is compressed; and (3) the spine cable nut hitting the thorax to
lumbar spine adaptor assembly.
Toyota Motor Corporate Services of North America (Toyota) also
informed NHTSA that it was concerned about ``unwarranted spine * * *
noise.'' (Letter to NHTSA from Mr. Saburo Inui, October 21, 1994.)
Toyota confirmed that the ``noise'' that AAMA found in the data traces
also occurred during Toyota's compliance and experimental development
tests. The manufacturer requested NHTSA to modify the SID
specifications by covering the spine cable with a shrinking plastic
tube and placing a rubber washer between the top-plate and the
fastening nut.
Subsequently, AAMA recommended specific corrections to the SID to
eliminate the spine ringing. In a December 13, 1994 letter (see item
88-07-N03-006 in NHTSA's docket), AAMA recommended adding Delrin
spacers in the top and bottom plates of the lumbar spine:
These spacers would be an efficient and effective way to correct
the spine ringing problem in the SID. They would be inserted into
the top and bottom plate of the lumbar spine assembly. No
modifications to the lumbar spine would be required for their use.
This would be cost effective for dummy users, since their inventory
of SID lumbar spines, would not have to be returned to dummy
manufacturers for rework. * * *
AAMA stated that Ford conducted component testing to determine the
effect of using the Delrin inserts on SID performance. Ford found that
when the Delrin spacers were used, the data spikes were eliminated.
AAMA also said that in subsequent crash tests conducted by member
companies, no indications of spine ringing were found when the spacers
were used. AAMA provided data to substantiate that relevant SID
responses would not be altered by the use of the spacers, i.e., they do
not alter the SID responses except for the elimination of spine noise.
AAMA also indicated that the spacers are durable and are readily
available from Vector Research, a dummy manufacturer.
On March 29, 1995, Mercedes Benz submitted a letter to NHTSA
supporting the use of the Delrin spacers, as suggested by AAMA. The
manufacturer stated: ``After much testing, we believe the AAMA has
provided sufficient evidence that artificial `noise' is eliminated by
using these spacers and that the relevant SID responses are not
affected.''
After receiving these letters and comments, NHTSA reviewed data it
obtained from tests with the SID for evidence of spine noise (spikes).
None of the available agency experimental or vehicle compliance data
indicated definitive evidence of data contamination and/or distortion
clearly attributable to spine cable snap. Further, it appeared from
data submitted by Ford that the ``noise'' that the manufacturer found,
while visible primarily in several portions of the raw data traces,
would nonetheless be reduced to insignificant values by the specified
FIR filter. Also, the noise consisted of extremely short duration
spikes occurring earlier or considerably later than the peak
acceleration magnitudes in real world crash tests. Usually such short
duration spikes do not have much energy content and accordingly, have
little or no effect on the true acceleration measurement, particularly
since they do not occur at points in time at which the TTIs are at
maximum.
While the agency's data did not show that spine noise was
problematic, NHTSA conducted further investigations to better
understand the manufacturers' concerns. In January 1995, NHTSA
determined through component tests of the SID torso that manufacturers
were correct that slippage of the SID's spine cable anchorage can
produce spikes in the data. (A July 1996 memorandum describing the
testing is in Docket 88-07, Notice 3.) In the component tests, the SID
upper torso part was rocked while the bottom half was held rigid. The
rocking tests caused the cable ends to slip, resulting in the
generation of low level ``clicking'' and some minor noise spikes in the
ribcage response data. It should be noted, however, that
[[Page 49994]]
none of the rocking motions producing spine cable snap generated spikes
that had any resemblance in shape or in magnitude to those described by
AAMA or Toyota.
NHTSA also found in the rocking tests that the Delrin spacers,
which AAMA suggested the agency should use in the SID spine, stopped
the cable from slipping and eliminated the clicking noise. In a series
of sled tests, NHTSA also determined that the spine inserts produce
somewhat less spikelike acceleration responses in the raw unfiltered
data compared to tests without the spacers. In a series of impact
tests, the agency established that the spacers had no appreciable
effects on stiffness of the spine, but resulted in lower magnitudes of
spikes in the ``z'' (vertical) acceleration channel. NHTSA also found
that the inserts have little, if any, effect on the TTI value
measurements. The above tests are described in a July 1996 memorandum
in Docket 88-07, Notice 3.
While the agency's data do not support the claims of some
manufacturers that spine noise affects the TTI(d) measurements
sufficiently to compel the possible redesign of their vehicles, NHTSA
has confirmed that the SID spine cable does move in a ``snap-like''
motion that can produce low level spikes that are clearly visible in
unfiltered raw data. This ``noise,'' while thus far negligible upon FIR
filtering, is nonetheless undesirable in itself as part of the crash
event. Any looseness or snapping of components within the SID can
produce rattling or unwarranted snapping effects that could potentially
distort the data from the dummy and possibly complicate compliance
testing. NHTSA therefore tentatively concludes that ``noise'' from
movement of the spine cable should be minimized to the extent
reasonably possible and that spacers inserted into appropriate places
in the spine are a reasonable means of effectively preventing such
movement. Accordingly, the agency proposes to amend the specifications
for the SID to incorporate use of lumbar spine spacers in Standard 214
compliance tests. Estimated cost of the two spacers is $154. Given that
on average, a SID can be used in at least 30 tests, the estimated cost
of the spacers is at most $5 per impact test.
Readers are invited to provide test data and comments relating to
their experience in testing dummies equipped with lumbar spine spacers.
Proposed Drawing Revisions
To incorporate the use of lumbar spine spacers, this proposal would
replace dummy assembly drawing SA-SID-M050, revision A (dated May 18,
1994) with revision B. Revision B would include reference to:
1. Drawing Lumbar Spacers-Lower SID-SM-001, which indicates the
spine lower spacer;
2. Drawing Lumbar Spacers-Upper SID-SM-002, which indicates the
spine upper spacer; and
3. Drawing 78051-243 to indicate a washer.
The drawings for the SID spine lower spacer and upper spacer are
depicted in this NPRM in figures 1 and 2, respectively.
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The SID users manual, dated May 1994, would be revised to reflect
the assembly of the above parts.
Damper Piston Movement
During the sled tests that the agency conducted to evaluate the
effect of spacer inserts in the SID lumbar spine, NHTSA observed that
the position of the damper piston in the SID ribcage prior to the test
had an appreciable effect on the thorax accelerations recorded by the
SID. In some tests, some of the thorax responses contained initial
short duration damper piston movement in the direction opposite of
impact, followed by a longer duration movement in the direction of
impact. Upon closer inspection of the damper piston position in dummies
set up for impact, NHTSA noted that the damper position was not fully
extended in some of the dummies. The agency subsequently found, through
tests with the damper piston position purposely fully extended or
partly compressed, that the damper piston's initial position can be an
important factor in determining whether the dummy's key thorax sensors
will record higher or lower accelerations.
In a side impact in which contact occurs first at the dummy's hip
level, a dummy's ribcage initially moves (relative to the pelvis bone)
toward the impact. When the damper piston is partly compressed prior to
impact, the damper piston will fully extend itself during impact until
it is arrested by the piston bottoming out against the damper body. The
test data indicate that this internal ``collision'' of the damper
piston against the damper body is the primary cause of inconsistency in
data measurements and the determination of acceleration levels. This
collision does not occur when the piston is fully extended within the
damper body prior to the test.
To better ensure that the impact response measurements are more
repeatable and reproducible, NHTSA proposes to specify in Standard
214's SID positioning procedures that the damper piston is in the fully
extended position before the test. Prior to sled tests that showed the
apparent damper piston position problem, the agency believed that a
piston return spring in the SID would develop sufficient force to set
the damper piston in the fully extended position. It appears, however,
that the spring is not stiff enough to set the piston in every dummy in
the fully extended position and that steps to ensure extension of the
piston are necessary.
NHTSA found that the piston can be fully extended by rocking a
seated dummy in the lateral direction immediately prior to a test or by
reaching through a partly unzipped SID torso jacket and forcing the
piston into a full extension. NHTSA believes these measures will ensure
that the damper piston is in the fully extended position at the time of
the side impact test. NHTSA tentatively concludes that a visual
inspection appears to be adequate to ensure that the piston is fully
extended and that a position sensor may not be needed. However, it is
noted that for users who want assurance, through measurements, that the
piston position is fully extended, the SID specifications package
already allows use of a ribcage position sensor as an option. The cost
of the sensor, with mounting brackets, is approximately $1,025.
Comments are requested on whether the SID specifications package should
require the use of a sensor.
Rulemaking Analyses and Notices
Executive Order 12866 and DOT Regulatory Policies and Procedures
NHTSA has considered the impact of this rulemaking action under
E.O. 12866 and the Department of Transportation's regulatory policies
and procedures. This rulemaking document was not reviewed under E.O.
12866, ``Regulatory Planning and Review.'' This action has been
determined to be ``non-significant'' under the Department of
Transportation's regulatory policies and procedures. The proposed
amendments would not require any vehicle design changes but would
instead only require minor modifications in the test dummy used to
evaluate a vehicle's compliance with Standard No. 214. According to
Vector Research, a dummy manufacturer, the two Delrin spacers (lumbar
spine inserts) cost $154. Thus far, these have been precision machined
parts aimed to satisfy individual low volume orders. The cost is
expected to decrease considerably once the other dummy manufacturer
(FTSS) begins manufacturing the spacers. If use of spacers increases,
dummy manufacturers may seek to produce them through precision molding,
which could further reduce the cost of the spacer. The agency has
determined that the impacts of the proposed amendments would be so
minimal that a full regulatory evaluation is not required.
Regulatory Flexibility Act
NHTSA has also considered the impacts of this notice under the
Regulatory Flexibility Act. I hereby certify that this proposed rule
would not have a significant economic impact on a substantial number of
small entities. Modifications to dummy designs affect motor vehicle
manufacturers, few of which are small entities. As described above,
there would be no significant economic impact on any vehicle
manufacturers, whether large or small. Further, since no price
increases would be associated with the proposed rule, small
organizations and small governmental units would not be affected in
their capacity as purchasers of new vehicles.
National Environmental Policy Act
NHTSA has also analyzed this proposed rule under the National
Environmental Policy Act and determined that it would not have a
significant impact on the human environment.
Executive Order 12612 (Federalism)
NHTSA has analyzed this proposal in accordance with the principles
and criteria contained in E.O. 12612, and has determined that this
proposed rule would not have significant federalism implications to
warrant the preparation of a Federalism Assessment.
Civil Justice Reform
This proposed rule would not have any retroactive effect. Under 49
U.S.C. 30103, whenever a Federal motor vehicle safety standard is in
effect, a State may not adopt or maintain a safety standard applicable
to the same aspect of performance which is not identical to the Federal
standard, except to the extent that the state requirement imposes a
higher level of performance and applies only to vehicles procured for
the State's use. 49 U.S.C. 30161 sets forth a procedure for judicial
review of final rules establishing, amending or revoking Federal motor
vehicle safety standards. That section does not require submission of a
petition for reconsideration or other administrative proceedings before
parties may file suit in court.
Submission of Comments
Interested persons are invited to submit comments on the proposal.
It is requested but not required that 10 copies be submitted.
All comments must not exceed 15 pages in length. (49 CFR 553.21).
Necessary attachments may be appended to these submissions without
regard to the 15-page limit. This limitation is intended to encourage
commenters to detail their primary arguments in a concise fashion.
If a commenter wishes to submit certain information under a claim
of confidentiality, three copies of the
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complete submission, including purportedly confidential business
information, should be submitted to the Chief Counsel, NHTSA, at the
street address given above, and seven copies from which the purportedly
confidential information has been deleted should be submitted to the
Docket Section. A request for confidentiality should be accompanied by
a cover letter setting forth the information specified in the agency's
confidential business information regulation. 49 CFR Part 512.
All comments received before the close of business on the comment
closing date indicated above for the proposal will be considered, and
will be available for examination in the docket at the above address
both before and after that date. To the extent possible, comments filed
after the closing date will also be considered. Comments received too
late for consideration in regard to the final rule will be considered
as suggestions for further rulemaking action. Comments on the proposal
will be available for inspection in the docket. The NHTSA will continue
to file relevant information as it becomes available in the docket
after the closing date, and it is recommended that interested persons
continue to examine the docket for new material.
Those persons desiring to be notified upon receipt of their
comments in the rules docket should enclose a self-addressed, stamped
postcard in the envelope with their comments. Upon receiving the
comments, the docket supervisor will return the postcard by mail.
List of Subjects
49 CFR Part 571
Imports, Motor vehicle safety, Motor vehicles.
49 CFR Part 572
Motor vehicle safety, Incorporation by reference.
In consideration of the foregoing, NHTSA amends 49 CFR Parts 571
and 572 as set forth below.
PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS
1. The authority citation for Part 571 would continue to read as
follows:
Authority: 49 U.S.C. 322, 30111, 30115, 30117 and 30166;
delegation of authority at 49 CFR 1.50.
Sec. 571.214 [Amended]
2. Section 571.214 would be amended by adding an introductory text
for S7.1, Torso, to read as follows:
S7.1 Torso. For a test dummy in any seating position, the piston
of the torso damper (SID 083) is fully extended.
* * * * *
PART 572--ANTHROPOMORPHIC TEST DUMMIES
3. The authority citation for Part 572 would continue to read as
follows:
Authority: 49 U.S.C. 322, 30111, 30115, 30117 and 30166;
delegation of authority at 49 CFR 1.50.
4. In section 572.41, the introductory text of (a), and paragraphs
(a)(4) and (c) would be revised to read as follows:
Sec. 572.41 General description.
(a) The dummy consists of component parts and component assemblies
(SA-SID-M001A, revision B, dated [to be determined] which are described
in approximately 250 drawings and specifications that are set forth in
Sec. 572.5(a) with the following changes and additions which are
described in approximately 85 drawings and specifications (incorporated
by reference; see Sec. 572.40):
* * * * *
(4) The lumbar spine consists of the assembly specified in subpart
B (Sec. 572.9(a)) and conforms to drawing SA 150 M050 and drawings
subtended by SA-SID-M050 revision B, dated [to be determined],
including the addition of Lumbar Spacers-Lower SID-SM-001 and Lumbar
Spacers-Upper SID-SM-002, and Washer 78051-243.
* * * * *
(c) Disassembly, inspection, and assembly procedures; external
dimensions and weight; and a dummy drawing list are set forth in the
Side Impact Dummy (SID) User's Manual, dated [to be determined]
(incorporated by reference; see Sec. 572.40).
* * * * *
5. In section 572.43, paragraph (a) would be revised to read as
follows:
Sec. 572.43 Lumbar spine and pelvis.
(a) When the pelvis of a fully assembled dummy (SA-SID-M001A
revision B, dated [to be determined] (incorporated by reference; see
Sec. 572.40) is impacted laterally by a test probe conforming to
Sec. 572.44(a) at 14 fps in accordance with paragraph (b) of this
section, the peak acceleration at the location of the accelerometer
mounted in the pelvis cavity in accordance with Sec. 572.44(c) shall be
not less than 40g and not more than 60g. The acceleration-time curve
for the test shall be unimodal and shall lie at or above the +20g level
for an interval not less than 3 milliseconds and not more than 7
milliseconds.
* * * * *
Issued on September 16, 1996.
L. Robert Shelton,
Acting Associate Administrator for Safety Performance Standards.
[FR Doc. 96-24206 Filed 9-23-96; 8:45 am]
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