[Federal Register Volume 70, Number 180 (Monday, September 19, 2005)]
[Proposed Rules]
[Pages 54889-54891]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-18593]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 572

[Docket No. 2005-22068]


Anthropomorphic Test Devices; Denial of Petition for 
Consideration Regarding Amending the Side Impact Dummy (SID); 
Specifications

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

ACTION: Denial of petition for rulemaking.

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SUMMARY: This notice denies a petition for rulemaking submitted by Ford 
Motor Company (Ford) on December 19, 2003, that asked the National 
Highway Traffic Safety Administration (NHTSA) to amend the Side Impact 
Dummy (SID) specifications in 49 CFR Part 572, Subpart F, for use in 
Federal Motor Vehicle Safety Standard (FMVSS) No. 214, ``Side Impact 
Occupant Protection,'' and the Side Impact New Car Assessment Program 
(Side NCAP).

FOR FURTHER INFORMATION CONTACT: For technical issues: Mr. Sean Doyle, 
NHTSA Office of Crashworthiness Standards. Telephone: (202) 366-1740. 
Facsimile: (202) 366-7002.
    For legal issues: Ms. Dee Fujita, NHTSA Office of the Chief 
Counsel. Telephone: (202) 366-2992. Facsimile: (202) 366-3820.
    Both officials can be reached by mail at the National Highway 
Traffic Safety Administration, 400 Seventh Street, SW., Washington, DC 
20590.

SUPPLEMENTARY INFORMATION:

Background

    On October 30, 1990, NHTSA published a final rule (Federal Register 
Vol. 55, No. 210, Docket Number 88-06; Notice 8) to amend FMVSS No. 
214, at the time titled, ``Side Door Strength.'' Prior to this final 
rule, a vehicle's side impact performance was determined solely by a 
static assessment of the ability of a door to resist forces imparted by 
a piston pressing a rigid steel cylinder against the door's outer 
surface. However, with the implementation of this final rule, effective 
September 1, 1993, vehicles were additionally required to undergo full-
scale dynamic crash tests to assess occupant protection. Because of its 
acceptable reliability and durability during research testing conducted 
in support of the final rule, the agency chose the SID to measure the 
potential for injuries to an occupant's thorax and pelvis in a side 
impact crash (Federal Register Vol.

[[Page 54890]]

55, No. 210, Docket Number 88-07; Notice 3). To provide an assessment 
of the dummy's measured readings, NHTSA developed an injury metric 
called the Thoracic Trauma Index (TTI).\1\
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    \1\ TTI is calculated by averaging the maximum filtered 
acceleration of the ribs (either the upper rib or the lower rib) and 
lower spine. The filter applied is a Finite Impulse Response (FIR) 
filter, which has a Passband frequency of 100 Hz, a Stopband 
frequency of 189 Hz, a Stopband gain of -50 db, and a Passband 
ripple of 0.0225 db.
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    FMVSS No. 214, renamed, ``Side Impact Protection,'' with the 
implementation of dynamic testing in 1990, was later amended on April 
2, 1998 (Federal Register Vol. 63, No. 63, Docket Number NHTSA-98-
3668). During sled tests conducted by the agency to evaluate the effect 
of adding spacer inserts to the SID lumbar spine, it was observed that, 
``the position of the damper piston in the SID ribcage prior to the 
[side impact] test had an appreciable effect on the thorax 
accelerations recorded by the SID.'' NHTSA further found that, ``the 
return spring on the damper did not always return the damper to its 
fully extended position.'' Because, in such instances, the piston was 
not fully extended in the dummy's ribcage prior to impact, the agency 
observed internal collision of the damper piston at the onset of impact 
in some dummies. Subsequent testing showed that internal collision 
within the damper body would not occur if the damper piston were in the 
fully extended position prior to a side impact test. Therefore, FMVSS 
No. 214 was amended on April 2, 1998, to include specific dummy 
positioning procedures to solve this problem.

Summary of the Petition

    In a letter dated December 19, 2003, Ford petitioned NHTSA to amend 
specifications for the SID in 49 CFR Part 572, Subpart F. Ford alleged 
that the damper in the SID dummy's thorax could induce erroneous, 
mechanical noise or ringing in the recorded data traces during side 
impact crash tests such as those conducted pursuant to FMVSS No. 214, 
``Side Impact Protection,'' or Side NCAP. Consequently, Ford modified 
the SID's thorax to include a SID ribcage deflection potentiometer, 
which allowed the company to assess the displacement of the damper 
piston (compression/extension) in the SID's thorax during side impact 
tests. Ford claims ``this mechanical ``noise'' or ``ringing'' is due to 
metal-to-metal contact between the SID ribcage damper piston and the 
damper body.'' The noise is present when the ribcage ``fully expand[s] 
allowing the damper piston to fully extend and bottom out on the damper 
body.'' In particular, Ford asserts this condition is present in 
certain vehicles tested both with and without side air bags.
    Ford presented unfiltered data for three vehicles equipped with 
side air bags that the company asserted were affected by internal 
collision of the damper piston against the damper body. For two of 
these side airbag equipped vehicles, Ford indicated, ``the SID thorax 
is initially loaded by the air bag positioning between the dummy and 
the vehicle door, then the thorax loading is relaxed due to the nature 
of the vehicle deformation and air bag kinematics, thereby allowing the 
damper piston to fully extend.'' As the crash event proceeds, Ford 
noted, ``the loading is re-applied to the thorax.'' According to Ford, 
during this ``loading/unloading/re-loading'' progression, ``the ribcage 
is initially compressed but then rapidly expands back to zero measured 
deflection indicating full extension of the damper piston.'' It is at 
this time, approximately 50-60 milliseconds (ms) from the initiation of 
the crash event, that Ford alleges erroneous spikes are present in the 
unfiltered thoracic data curves. In the third vehicle, Ford stated that 
the internal collision occurred ``late in the crash event when the 
dummy is in rebound'' and ``therefore does not influence * * * dummy 
performance.'' Contrary to that which occurred for the other two 
vehicles, in this vehicle, the dummy's ribcage was continuously 
compressed until the loading subsided at the end of the crash event.
    Ford also presented unfiltered data from one vehicle that was 
tested without side air bags. In such a vehicle, the company contends, 
``the phenomenon can occur when the door structure of the vehicle 
initially loads the SID thorax as the FMVSS-214/LINCAP [Side NCAP] 
barrier intrudes, then the loading is relaxed due to the kinematics of 
the vehicle's deformation thereby allowing the internal ``collision'' 
of the piston and damper body.'' This resulted in a sharp spike at 50 
ms in the raw data traces. Ford further stated that the dummy's thorax 
is then reloaded ``when the SID rotates outboard and contacts the door 
structure a second time during the crash event.''
    Ford maintained that if ``the ribcage damper piston can fully 
extend during the dummy loading event, * * * the internal ``collision'' 
phenomenon can significantly affect the measured rib and spine 
accelerations by introducing data spikes `` even with the FVMSS-214 
specified FIR [Finite Impulse Response] -filtering process.'' Ford also 
stated, ``the resulting data spikes in the SID responses can register a 
magnitude and duration such that the resulting Thoracic Trauma Index 
calculation can be unrealistically high, with the potential to result 
in a value exceeding FVMSS No. 214 limits and/or to reduce a vehicle's 
LINCAP rating by one or more stars.''
    In an attempt to mitigate the spikes, Ford asked Denton ATD, Inc. 
to develop modifications for the SID ribcage damper, which included the 
addition of both an internal 1-2 mm thick nylon washer and a 7 mm 
external steel spacer to the piston shaft. Ford claimed that the 
internal nylon washer ``creates a more `compliant' bottoming out 
surface on the piston shaft, thereby reducing the likelihood of 
mechanical `ringing' due to metal-to-metal contact between the shaft 
and damper body.'' Ford also stated that the external spacer would 
``provide more piston stroke length, thereby reducing the likelihood of 
bottoming out the piston against the damper body.'' Ford believes that 
the above modifications ``do not alter the SID response characteristics 
associated with FMVSS-214 compliance or LINCAP performance (except for 
reducing or eliminating the ringing from metal-to-metal contact), and 
will comply with all regulatory SID dummy response calibration 
requirements.'' Therefore, Ford petitioned NHTSA to amend the SID 
specifications to incorporate the aforementioned modifications to the 
damper and accordingly, modify all SIDs used by contracting 
laboratories.
    In addition to the modifications discussed previously, Ford also 
requested that NHTSA add a ribcage deflection potentiometer to the SID 
specifications and the corresponding mounting bracket design that they 
currently use. Ford claims that this assembly ``aids in the diagnosis 
and verification of the metal-to-metal contact condition.'' Ford stated 
that the mounting bracket design presently used in their internal 
testing ``was developed by NHTSA during the evolution of the bracket 
design associated with the [1986] NPRM'' (Federal Register Vol. 53, No. 
17, Docket Number 88-06; Notice 1). However, Ford stated that unlike 
the mounting bracket design that was proposed in 1986, this ``modified 
design'' precludes potential metal-to-metal contact.

Analysis of Petition

    NHTSA acknowledges that the unfiltered peak acceleration traces for 
the upper rib, lower rib, and lower spine presented by Ford in the 
petition appear to show evidence of ``mechanical

[[Page 54891]]

noise,'' and the most prominent spikes in these curves tend to occur 
around 45-60 ms after the initiation of the crash event. However, as 
Ford noted in the petition, the agency recognizes that internal 
collision of the piston against the damper body is possible, and that 
such contact could produce a ringing signal in the resulting data 
traces (Federal Register Vol. 63, No. 63, Docket Number NHTSA-98-3668). 
For that reason, in 1998, the agency amended the SID positioning 
procedure to fully extend the piston within the damper body prior to 
the side impact test to preclude the piston from bottoming out against 
the damper body at the onset of impact. However, Ford did not provide 
evidence to indicate that the SID positioning procedures outlined in 
the 1998 final rule were in fact followed for the tests discussed in 
this petition. Therefore, the agency cannot be certain that the 
``mechanical noise'' documented by Ford is not a result of improper 
pretest SID positioning. Similarly, Ford did not provide data showing 
the effects on TTI with application of the FIR filter. Nevertheless, to 
ensure that the performance of the SID had not changed since its 
incorporation as a regulatory tool, NHTSA reviewed its own side impact 
test data.
    In analyzing Side NCAP test data spanning model years (MY) 1997-
2004 and indicant \2\ FMVSS No. 214 test data spanning MY 2000-2004, 
NHTSA found only a few instances in which the upper rib, lower rib, or 
lower spine unfiltered data traces for the driver or rear passenger SID 
in vehicles tested show data spikes at approximately the same timeframe 
(~ 50 ms) indicated in the Ford petition.\3\ However, NHTSA's analysis 
also showed that ``noise'' effects are considerably reduced, if not 
nullified, by application of the FIR filter. Therefore, the agency 
could not establish that the dummies' base acceleration response levels 
were elevated sufficiently to affect the TTI. Consequently, there is no 
evidence to suggest that the star ratings for Side NCAP vehicles were 
reduced because of mechanical noise. A similar review of thoracic data 
traces for the driver and rear passenger dummies in vehicles subjected 
to FMVSS No. 214 compliance tests from MY 1998-2003 uncovered a very 
limited number of vehicles in which a ringing signal was apparent 
between approximately 50-60 ms in the raw data traces. These spikes 
were significantly reduced once the FIR filter was applied. Hence, 
NHTSA has concluded that similar to the Side NCAP tests, the recorded 
TTIs for the dummies in the compliance tests were not affected to the 
extent that a vehicle would have exceeded the injury criteria imposed 
by FMVSS No. 214.
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    \2\ Indicant FMVSS No. 214 tests are conducted by the Office of 
Vehicle Safety Compliance, but are performed at the Side NCAP test 
speed of 38.5 mph instead of 33.5 mph, as specified in the FMVSS No. 
214 standard.
    \3\ Spikes occurring considerably later than typical peak 
acceleration magnitudes seen in side impacts (from approximately 150 
milliseconds to approximately 200 milliseconds) were present in the 
agency's data as well. However, the agency has found that FIR 
filtering makes such spikes negligible compared to the peak 
acceleration at impact. Side NCAP vehicle test data is located in 
Docket No. 1998-3835.
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    Ford additionally requested that the agency incorporate the ribcage 
deflection potentiometer and corresponding mounting bracket used in 
Ford's in-house tests to aid in the diagnosis and verification of 
metal-to-metal contact occurrence. Based on our analysis, NHTSA does 
not believe that these recommended changes are either needed or would 
serve the needs of safety. Therefore, the agency is choosing not to 
incorporate the ribcage deflection potentiometer and corresponding 
mounting bracket, or the internal washer and external spacer.

Conclusion

    NHTSA did not find compelling evidence in the limited unfiltered 
data provided by Ford to suggest that the claimed erroneous 
acceleration data spikes are a cause of compliance problems or result 
in reduced Side NCAP star ratings. Furthermore, a review of the 
agency's own side impact test data did not reveal any instances in 
which data spikes affected TTI to the extent that a vehicle did not 
meet the FMVSS No. 214 compliance limits or was unjustly given a lower 
star rating. Consequently, NHTSA feels that the currently specified SID 
is sufficiently suitable for FMVSS No. 214 and Side NCAP objective 
testing and deems that the requested modifications are not needed. 
NHTSA is therefore denying the Ford petition for rulemaking.

    Authority: 49 U.S.C. 30162; delegations of authority at 49 CFR 
1.50 and 49 CFR 501.8.

    Issued on: September 13, 2005.
Stephen R. Kratzke,
Associate Administrator for Rulemaking.
[FR Doc. 05-18593 Filed 9-16-05; 8:45 am]
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