[Federal Register: April 5, 2004 (Volume 69, Number 65)]
[Proposed Rules]
[Page 17622-17627]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr05ap04-26]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571 and 572
[Docket No. NHTSA 2003-11398]
Denial of Petition for Rulemaking
AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT.
ACTION: Denial of petition for rulemaking.
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SUMMARY: This notice denies a two part petition submitted by the
Alliance of Automobile Manufacturers (Alliance) under a cover letter of
July 19, 2002. The petitioner asked the agency to amend: (1) Part 572
by adding two new subparts to set out specifications for the Occupant
Classification Anthropomorphic Test Devices (OCATD-5 and -6), and (2)
Federal Motor Vehicle Safety Standard (FMVSS) No. 208 specifications to
allow alternative use of OCATD-5 and -6 for manufacturer certification
of static suppression test requirements.
FOR FURTHER INFORMATION CONTACT: For Non-Legal Issues: Mr. Stan
Backaitis, Office of Crashworthiness Standards, NVS-110, National
Highway Traffic Safety Administration, 400 Seventh Street, SW.,
Washington, DC 20590. Telephone (202) 366-4912. Fax: (202) 473-2629.
For Legal Issues: Ms. Rebecca MacPherson, Office of Chief Counsel,
NCC-20, National Highway Traffic Safety Administration, 400 Seventh
Street, SW., Washington, DC 20590. Telephone: (202) 366-2992, Fax:
(202) 366-3820.
SUPPLEMENTARY INFORMATION: The Alliance of Automobile Manufacturers
(Alliance) in a letter of July 19, 2002, petitioned the National
Highway Traffic Safety Administration (NHTSA) to amend part 572 by
adding two new subparts to set out specifications for the Occupant
Classification Anthrpomorphic Test Devices (OCATD-5 and -6) and to
amend FMVSS No. 208 to allow alternative use of OCATD-5 and -6 for
manufacturer certification of advanced air bag static suppression test
requirements. The petition was accompanied by a University of Michigan
Transportation Research Institute (UMTRI) based Technical Report
containing the following attachments: (1) ``Anthropometric and
Performance Standards for the OCATDs'' (Attachment A), (2)
``Quantitative Evaluation of the Seat Pressure Measurements, Body
Weight Distribution and Posture Effects on Those Measurements''
(Attachment B), and (3) OCATD-5 and -6 drawing packages (Attachments C
and D, respectively).
Issues Raised in the Petitions
FMVSS No. 208 requires that frontal passenger air bag systems
either suppress deployment or deploy in a low risk manner during
frontal collisions when a small child is present. Also the manufacturer
must pass the dynamic performance requirements of the standard, which
usually requires deployment of the air bag for the 5th percentile
female dummy. One provision of the standard specifies that suppression
systems may be tested using either small adult female and six-year-old
Hybrid-III dummies, or human volunteers who approximately match those
body sizes. The Alliance states that:
(1) Crash test dummies are poorly suited to the development and
certification of the occupant classification components of some
advanced air bag systems because:
Hybrid-III and THOR crash dummies do not produce
required humanlike seat surface pressure distributions,
Development of occupant classification systems
requires testing of surrogates in a wide range of postures, but many
postures that are possible for humans cannot be attained with the
specified crash test dummies, and
Hybrid-III dummies are difficult to position and
may not appear human-like to some types of sensors used for occupant
classification purposes.
[[Page 17623]]
(2) Testing with human volunteers is time-consuming and requires a
large number of subjects. It reduces repeatability to a level that is
unacceptable for product development and would not provide the
objectivity of compliance should the vehicle subsequently be tested
with different human beings.
(3) The OCATD-5 and -6 should be added to FMVSS No. 208 as an
optional means of certifying vehicles to the static suppression test
requirements because (1) they are capable of comparable performance to
the Hybrid-III 6-year-old and 5th percentile female dummies for
purposes of occupant classification using pressure distribution
discrimination, and (2) they offer the advantage of superior
flexibility and posture capability compared to the Hybrid-III dummies.
Background
Appendix D of the Final Rule preamble for FMVSS No. 208, ``Occupant
crash protection,'' (65 FR 30743, May 12, 2000) notes, that:
Advanced air bag systems can use various types of sensors to
obtain information about crashes, vehicles and their occupants. This
information can be used to adapt the performance of the air bag to
the particular circumstances of the crash. As noted above, it can be
used in determining whether an air bag should deploy, when it should
deploy, and (if it has multiple inflation levels) at what level of
inflation (pressure rise) and inflation rate (pressure rise rate).
* * * * *
Strategies for static occupant detection systems include the
ability to make a determination of whether air bag deployment is
warranted (or what level of inflation is appropriate) for the size
and/or position of the occupant (e.g., whether the occupant is a
small child or a full-sized adult, or whether the occupant is
against the seat back or is sitting on the edge of the seat, closer
to the air bag). These technologies may be used in conjunction with
seat weight sensing/pattern recognition systems (or seat belt use
and crash severity sensing) to improve the reliability of the
occupant classification and location estimates.
Furthermore, the agency noted in 65 FR 30693, May 12, 2000, that:
For our proposed static test requirements for systems which
suppress air bags in the presence of infants and children (e.g.,
weight sensors), we proposed a new option which would permit
manufacturers to certify to requirements referencing actual
children, instead of 3-year-old and 6-year-old child dummies, in a
stationary vehicle to test the suppression systems. (This option
would not apply to systems designed to suppress the air bags only
when an infant is present.) Adult human beings could also be used in
the place of 5th percentile adult female dummies for the portions of
those static test requirements which make sure that the air bag is
activated for adults.
The Alliance stated in its petition that:
Development and testing of occupant classification systems also
requires testing surrogates in a wide range of postures, but many
postures that are possible for humans cannot be attained with crash
dummies. In particular, the Hybrid-III dummies are difficult to
position and may not appear human-like to some types of sensor
systems used for occupant classification. Testing with human
volunteers, which is time-consuming and requires large numbers of
subjects, reduces repeatability to a level that is unacceptable for
product development and would not provide the objectivity of
compliance should the vehicle subsequently be tested with different
human beings.
The Alliance cited a 1999 UMTRI study in which it is claimed that
``existing human surrogates, such as the Hybrid-III and THOR crash test
dummies, do not produce human-like seat surface pressure distributions
(Reed et al., Technical Report UMTRI-99-46, 1999b).''
A similar observation was voiced in Toyota's comments to the FMVSS
No. 208 Supplementary Notice of Proposed Rulemaking [NHTSA-1999-6407]
for advanced air bags concerning the suitability of current test
dummies and humans in automatic suppression tests. Toyota urged the
agency to work initially with industry in developing better test
dummies capable of activating automatic suppression systems when
occupancy conditions warrant deployment suppression. Mitsubishi's
comments echoed this request. Toyota claims as many as 50 percent of
the tests conducted by/or on behalf of Toyota with the 5th percentile
adult female test dummy did not detect the presence of that dummy at
the weight needed to turn off the suppression system. Toyota also
voiced dissatisfaction with the option of certifying their systems
using humans who are within specified height and weight range. Toyota
believes those parameters allow too much variation in physiology to
make humans practical test objects. Toyota maintained that NHTSA should
specify that it will conduct its compliance tests using the same test
subjects or devices that vehicle manufacturers employed to certify
their suppression systems.
In line with these concerns, the petitioners stated that
specialized test devices need to be developed to represent humans
quantitatively in at least the following set of characteristics: (1)
External anthropometry, (2) accurate skeletal linkage and joints, (3)
total body mass and segment masses, and (4) most importantly, seat
surface pressure distributions. As a result, the Alliance has provided
financial support for the development of two such devices, called
OCATDs, in the small adult female and six-year-old child
configurations. In March 2000, First Technology Safety Systems (FTSS)
was awarded the prime contract to develop and build the prototype
OCATDs. UMTRI, as a subcontractor to FTSS, was to provide anthropometry
and performance specifications for the small adult female and six-year-
old child.
An initial literature search was conducted by UMTRI to establish
the body dimensions and surface contours of the typical six-year-old
child. This information was used to determine the anthropometric
specifications for the OCATD-6. Subsequently, seat surface pressure
distributions produced by sixty-eight children and small women were
measured in a range of seats and postures to determine the pressure
distribution performance targets for both the small adult female OCATD-
5 and OCATD-6.
A second research program at UMTRI involved quantitative
comparisons of the seat surface pressure distributions and weight
distributions produced by the small adult female and six-year-old
Hybrid-III dummies. The distributions were measured and compared to
those produced by human occupants and the OCATDs [Reed et al.,
Technical Report UMTRI-2000-38, 2000]. The quantitative comparison was
made using pressure-distribution parameters that were demonstrated in
the previous research to have value for occupant classification
purposes. The positions and postures of the surrogates were recorded
using a coordinate measurement machine to quantify the repeatability of
the installation procedures. In addition, the support forces under the
feet of the surrogate were recorded to evaluate the extent to which the
weight borne by the seat varied with posture.
OCATD Construction
The UMTRI report notes that initial anthropometry and weight
targets for the OCATD-5 and OCATD-6 were defined by the stature and
weight ranges specified in FMVSS No. 208. OCATD-5 represents a 5th
percentile size small female with a stature of 1450 mm (55 in.) and
weight of 46.7 kg (103 lb). OCATD-6 represents a six-year-old child
with a stature of 1181 mm (46.5 in.) and weight of 23.5 kg (51.6 lb).
These specifications were subsequently verified by using the Consumer
Product Safety Commission and National Health
[[Page 17624]]
and Nutrition Examination Survey (NHANES) data bases as reference.
The OCATDs were constructed as soft, deformable, headless, and
armless devices having the shape, anthropometry, and mass of the human
torso and legs. The OCATD's fundamental construction is a soft
deformable urethane flesh material molded over a human-like skeleton
similar to a surrogate developed in prior years for the seat
manufacturing industry. [Don Adams et al, SAE 1999-01-0627].
The OCATD skeleton is made from molded plastic with metal inserts at
the joints. Pivots at the T12/Ll and L5/S1 vertebrae locations allow
the spine to rotate in the sagittal \1\ plane, and ball joints at the
femur/pelvis interface allow hip rotation and leg abduction/adduction
to simulate various human postures. The joints can be locked, allowing
the dummy to sit erect without external support. The torso section is
divided into three segments--upper thorax, abdomen, and pelvis/thighs.
The abdominal segment is made of compressible urethane foam to allow
the device to lean forward, and is removable to access ballast weights.
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\1\ Sagittal--inferior/superior plane parallel to the
longitudinal axis of the body.
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Torso Postures
The UMTRI report claims that the OCATD devices can be pre-
positioned to three torso orientations: Normal (design), reclined to 48
degrees, and erect. The normal torso orientation of a seated occupant,
as determined in the UMTRI seating study, is defined by a thorax back
angle of 24.6 degrees relative to the vertical. In erect orientation,
the OCATD spine joints can be locked into position for unsupported
seating. The posture and torso orientation can be monitored with tilt
sensors in the pelvis and spine.
Analysis of the Petition
The Alliance petition notes that the OCATDs have only slightly
better performance than Hybrid-III 6-year-old and 5th percentile female
dummies for purposes of occupant classification using pressure
distribution discrimination. However, the Alliance believes the OCATDs
may have the added advantage of superior flexibility and posture
capability compared to the Hybrid-III devices. The Alliance thinks the
results of its research will ``provide quantitative guidance to
manufacturers for selecting surrogates, and developing test procedures
for use with advanced air bags''.
Since the Alliance petition is based primarily on UMTRI's
evaluation of the OCATDs, we have examined the UMTRI report for the
benefits claimed in the Alliance petition. The UMTRI report notes that
the measured seat pressure data were analyzed with three objectives:
1. To determine the pressure distribution parameters from human
tests that provide the greatest ability to classify occupant size,
2. To identify performance targets for the OCATD devices with
respect to seat surface distribution, and
3. To assess the performance of the OCATDs relative to the
performance targets.
Pressure Distribution Parameters
The UMTRI report notes that of the measured data, three parameters
emerged that could be used to describe the seat surface pressure
distributions. UMTRI found that in sorting pressure distributions by
the resulting R2 value, the best predictors for normal
seating posture were: (1) The PeakRowWidth \2\ (R2=0.88),
(2) CentroidRowWidth \3\ (R2=0.86), and (3) PseudoweightLb
\4\ (R2=0.85). For non-normal seating postures, the best
predictor is the PseudoweightLb (R2=0.78). Further studies indicate
that correlation among parameters, using their multiples, do not
substantially improve the prediction of body weight.
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\2\ Lateral width of pressure distribution at fore-and aft
location at the highest pressure, evaluated under contact area
exceeding 10mmHg.
\3\ Summation of pressures across all sensors multiplying by
sensor area and expressing the results in pounds.
\4\ PseudoweightLB is the product of the sensor area and
pressure and is a rough measure of the weight borne by the seat
cushion.
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The analysis of a large number of pressure distribution parameters
allowed UMTRI to specify and evaluate the OCATD performance. The OCATD
pressure distributions are determined, to a large extent, by the weight
of the occupant and the external anthropometry (hip breadth, buttock-
to-knee length, etc.). The analysis of pressure distribution data from
human subjects demonstrated that the parameters of pressure
distribution that are useful for occupant classification also relate to
scale (width and length of the respective contact area of the buttocks
with the seat cushion). Consequently, UMTRI believes that using
representative anthropometry for the OCATDs is a major part of
achieving representative pressure distributions.
UMTRI noted that the observed OCATD seated pressure parameter
values can be assessed by comparing them to the distribution of similar
parameter values expected for people who meet the OCATD stature and
weight criteria. If the OCATD parameter values lie within one standard
deviation of the target, the OCATDs are substantially representative of
the occupant category. If the discrepancy is larger than two standard
deviations, the OCATD parameter values are unusual for the
corresponding anthropomorphic category.
Using this approach, UMTRI found the quantitative performance of
the OCATDs with respect to human pressure distribution to be good.
Among the top ten classification parameters, the OCATDs generally
differed by less than one standard deviation from the targets. UMTRI
claims that in percentage terms, the deviations from the targets are
generally less than five percent.
Pressure Distribution Measuring Systems
UMTRI observed that defining the precision and accuracy for seat
pressure distribution measurement systems is extremely difficult. A
number of very difficult to control variables plague the technology of
pressure measurements. For example, when a pressure mat is placed
between two flat surfaces, pressure can be applied and measurements
made in readily quantified ways. However, the interface between a
occupant's compliant buttocks and a compliant seat is not flat, and may
include substantial shear stress, as well as normal stress related
pressure measurements. Thus, in actual evaluation of such compliant
surfaces, it is very difficult to determine the ``true'' pressure.
UMTRI notes that measurements of seat surface pressure distribution are
at best regarded as approximate and used as relative measures only. For
example, measuring the pressure distribution on two seats with the same
subject might lead to the conclusion that the pressure was higher on
one seat than the other. UMTRI states that the difference can not be
confidently quantified within ten or 15 percent because of differences
in the shape and contours of the contact area and the limitations of
the sensor system. Accordingly, the ability of the OCATDs to produce
consistent measurements in compliance tests would always be in
question.
Application Issues
UMTRI indicated that pressure measurements are strongly affected by
the occupant's posture. Over the range of postures and subjects
studied, the effects of posture on pressure distribution may be larger
than the effects of body size. This poses problems for validating the
OCATD
[[Page 17625]]
pressure distribution performance. Thigh posture strongly affects
contact area, and is one of the parameters most useful for occupant
classification, making it an important factor for OCATD validity. UMTRI
suggested that the OCATD should be used in a range of thigh postures
from fully to minimally engaged, representing a range of the seat
loading conditions expected in the field. The extremes might capture
the human variance in ``normal'' postures and be an appropriate way to
specify OCATD positioning for certification testing.
The UMTRI test data show that the OCATD pressure distributions are
likely to be most representative of human pressure distributions in
soft seats. In seats that are very firm, the OCATD contact area tends
to be smaller than that of comparably sized humans. This is because the
OCATD flesh is stiffer than that of humans. In a firm seat, the OCATD
flesh does not spread as widely as the softer human tissue, and
consequently produces a smaller contact area. However, UMTRI found that
differences in contact areas between firm and soft seats were smaller
than differences due to leg(s) postures.
Repeatability and Reproducibility
UMTRI observed that because of limitations of pressure distribution
measurement technology, the OCATD itself is probably more repeatable
than the sensors used to measure the contact pressures. UMTRI also
found, that the posture and the positioning of the OCATD appeared to be
more important than the shape or stiffness of the device in determining
the seat surface pressure distribution. Hence, repeatability and
reproducibility studies of the OCATDs need to focus primarily on
installation variability. In addition, UMTRI recommended that
procedures and test tools need to be developed to verify that soft
tissue stiffness and contours of the OCATDs remain within
specification.
Comparison of OCATDs With Hybrid-III Dummies
The UMTRI report claims that seat surface pressure distributions
produced by the OCATDs are visually more similar to human pressure
distributions than those produced by the Hybrid-IIIs. However, our
review of UMTRI's quantitative analysis found that the small adult
female Hybrid-III is approximately as representative of small adult
women as the OCATD-5 with respect to the parameters of seat surface
pressure distribution that are related to the occupant's body weight.
UMTRI found the six-year-old Hybrid-III pressure distribution
parameters to be somewhat less representative of six-year-old children
than the OCATD-6. The pressure distributions were somewhat narrower and
smaller in area than those obtained with humans. However, even in this
respect, the data from the UMTRI study indicated that pressure
distributions produced by the Hybrid-III dummies were generally within
the range of variability expected for humans of similar size.
UMTRI noted that OCATD buttock contours and spacing of the peak
pressure from the ischial tuberosity bones appear to be a better match
to the human pressure distributions than those produced by the Hybrid-
IIIs. UMTRI observed that much of the correspondence is not meaningful,
because neither the contours nor the location and spacing of these peak
pressures are useful for occupant classification purposes. These
observations appear to project UMTRI's findings based on this specific
study. However, the agency is aware that some suppression systems
utilize seat map pressure sensors to classify the occupant based upon
its morphology (http://www.iee.lu/EN/AutoProd/).
The only parameter in which the Hybrid-IIIs differed substantially
from the OCATDs and the human targets in the UMTRI study was
``PseudoweightLb''. However, ``PseudoweightLb'' is difficult to
interpret because it is affected by the shape and contours of the
contact surface. The pressure distribution measurement system measures
the aggregate force perpendicular to the surface of the measurement
pad. However, as described above, shear stresses on compliant surfaces
are in evidence and responsible for much of the measurement
inaccuracies. Thus, UMTRI believes, the more flattened buttock shape of
the Hybrid-III dummies may have accounted for the difference in
``PseudoWeightLb'' assessment.
UMTRI noted that the OCATDs are easier to position and are capable
of a wider range of postures than the Hybrid-III counterparts. However,
the FMVSS No. 208 advanced air bag certification test procedures do not
require a large range of postures for air bag suppression testing.
Thus, while there might be interest by some vehicle manufacturers to
employ the OCATDs for vehicle development purposes, there is virtually
no advantage in using them in FMVSS No. 208 compliance tests.
As only one of each type of OCATDs was used by UMTRI in its
testing, it is possible that differences within any new surrogate
category could affect the findings. These differences may become even
larger through their use and as the flesh materials age. Also, as with
any study of this type, the applicability of the findings is limited to
the types of seats and postures used. The characteristics of the
pressure distribution measurement system would also greatly influence
the test results. In particular, a pressure sensing system with lower
resolution, such as most of those used by vehicle manufacturers in
production seats, may show substantially larger or smaller differences
between the various surrogates and the humans. Inasmuch as the Alliance
has not provided estimates of potential variabilities, the agency is
not in a position to address this issue.
Other Considerations
The agency has no testing experience with the OCATDs. The
Alliance's (summer 2002) offer to provide the agency one of the OCATDs
for evaluation purposes did not materialize in its delivery; while the
agency, due to other high priorities and in expectation of receiving
the OCATD, had not pursued its independent acquisition. However, in the
interim, the agency has gained considerable knowledge about the OCATDs
during the review of the UMTRI reports, such as their usefulness and
applicability for air bag suppression purposes. In addition, a limited
amount of information was also obtained when FTSS made an introductory
presentation to agency staff in the spring of 2002, and at the
government-industry meeting in July 2002. The latter information is
available on the NHTSA Web site.
FTSS has disclosed that it has sold over 20 OCATDs. A larger
portion of them are female versions. The purchasers are mostly
manufacturers producing vehicles for the U.S. market. However, the
agency has no knowledge on how the manufacturers are using these test
devices, whether their use is providing correct signals for sensing the
need to activate/deactivate deployment systems, and whether the devices
can effectively replace the human population for the intended purposes.
FTSS also indicated that some users may be considering capacitive
systems for activation purposes. In such systems, FTSS suggested the
possibility of incorporating copper wire mesh that would be imbedded in
the OCATD skin. The intention of this effort would be to simulate the
capacitive properties of the human body. However, UMTRI notes that the
built-in electrical properties would not necessarily reflect a
particular size human. Accordingly, these types of systems by
themselves may not be sufficient discriminators for suppression
purposes. It appears that
[[Page 17626]]
manufacturers considering use of capacitive systems would have to find
other methods to match the outputs of complementary weight distribution
or pressure sensing systems.
Summary of Analysis and Conclusions
Review and analysis of the documents presented in the petition lead
to the following observations and conclusions:
1. Contact pressure measuring technology shows the need for a
substantial amount of development before it can be used reliably and
repeatably for pressure distribution and pressure pattern measurements.
2. Since the choice of the in-vehicle seat based pressure sensing
system is controlled by vehicle manufacturers, the agency would have
great difficulty assuring the suitability and appropriateness of the
OCATDs for assessing adequacy and effectiveness of any particular
suppression system for the intended human population.
3. Because vehicle models and seat designs change quite frequently,
the built-in pressure sensing system in a vehicle seat might be
tailored for the OCATDs rather than correctly sensing the suppression
for the intended population groups.
4. The supporting materials provided with the petition indicate
that the proposed OCATDs are only marginally different or better, if at
all, than the Hybrid-III dummies in replicating human-like seating
pressure distribution measurements. Accordingly, there is virtually no
advantage in using the OCATDs as substitutes for Hybrid-III dummies
within the parameters currently specified for compliance suppression
testing.
5. Pressure distributions for the OCATDs and Hybrid-III dummies
fall within the general range of variability expected for humans of
similar size. Thus the OCATDs do not provide any more effective sensing
for deployment suppression than the Hybrid-III dummies.
6. The OCATDs may have some advantages for more accurate pressure
measurement distribution on firmer seats, but this is still to be
demonstrated.
7. Posture variations and leg support appear to have more
significant effects on pressure distribution parameter measurements
than the occupant's weight and size. Procedures to stabilize the OCATD
set-up and assure consistency of contact pressure measurements are
still to be established.
8. The agency has no knowledge that the OCATDs are easier to
position than comparable Hybrid-III dummies for certification purposes.
Considering the small size and low weight of the Hybrid-III small
female and 6-year-old dummies, the agency does not believe the supplied
data support significant use advantages between the two dummy types.
9. While the petitioner notes that the OCATDs offer a significantly
wider range of postures than Hybrid-III dummies, the agency compliance
requirements limit the application of the female dummy to only one
posture and the six-year-old to four seated posture configurations
(normally seated, leaning against the door, reclined and full up front)
in suppression tests.
10. The agency has not tested or evaluated either of the petitioned
OCATDs or pressure sensing instruments. Agency personnel would have to
develop technical expertise and equipment to deal with the devices and
the various sensing technologies as well as their limitations for no
apparent benefit.
11. To test, evaluate, and incorporate the OCATDs, as petitioned by
the Alliance, would require a large expenditure of scarce agency
resources and divert them from work that would yield far greater safety
benefit.
12. In view of the limitations and/or questionable usefulness of
the OCATDs for occupant sensing, their alternate use for compliance
certification would not be acceptable either from the safety assurance
point of view or for avoidance of claims and counterclaims on the
appropriateness of the test results with respect to human test
subjects.
13. The agency sees no reason why vehicle manufacturers should not
use the OCATDs for their own purposes as opposed to aid in
certification, if they are convinced that OCATDs will provide them
superior flexibility in the design of better functioning air bag
suppression systems. However, the agency sees neither any advantages
nor need in using the OCATDs within the parameters currently specified
for deployment of suppression certification tests.
Summary of Agency Position and Decision
The agency has decided to deny the Alliance petition to incorporate
the OCATD-5 and -6 test devices into part 572. The agency finds that
the Alliance has not provided compelling evidence that would support
the need to specify the OCATD-5 and -6 devices as alternates to the
Hybrid-III small female and the six-year-old dummies, or human
volunteers, in FMVSS No. 208 for suppression certification tests. The
Alliance documentation failed to demonstrate how use of the OCATDs
would provide an advantage due to their superior flexibility and
posture capability in the currently specified agency test procedure.
Accordingly, the agency is also denying the Alliance petition for
alternate use of OCATD-5 and -6 for manufacturer certification to
static suppression test requirements in FMVSS No. 208.
Agency analysis of the petitioner's data indicates that of the two
OCATDs, only the OCATD-5 appears to have marginally better pressure
distribution indications than the respective Hybrid-III dummy. Even so,
both OCATDs and Hybrid-III dummies fall within the general range of
variability expected for humans of similar size. In addition, the
agency has no substantiating evidence to verify the Alliance claim that
OCATDs are easier to position than comparable Hybrid-III dummies.
Considering the small size and low weight of the Hybrid-III small
female and the 6-year-old dummies, and the few positions specified for
FMVSS No. 208 certification, the agency believes the supplied data do
not support OCATDs' use for static air bag deployment suppression
tests.
The agency does not agree with the Alliance assertion that
development and testing of occupant classification systems, as
currently specified in the agency compliance procedures, require
testing surrogates capable of a wide range of postures. It needs to be
noted that agency compliance specifications limit the female dummy set-
up to only one posture for suppression testing and four different
postures for the six-year-old. The agency has had no difficulties in
its tests to attain the required positions and postures with the
respective Hybrid-III dummies. Furthermore, GM and Honda have already
certified advanced static suppression systems without indication of the
need for OCATDs to advance this technology.
We agree with the Alliance that testing with human volunteers is
time-consuming and requires large numbers of subjects. However, none of
the available human surrogates will assure 100 percent suppression
effectiveness. The agency allowed testing with humans in order to
permit those vehicle manufacturers who are uncomfortable with the
results from dummy tests to certify the suppression systems with
suitable human vehicle occupants.
Our review of the contact pressure measuring technology for shaped
and conforming seat cushions show the need for a substantial amount of
further research before ``true'' pressure measurements can be made.
Accordingly, the agency believes the
[[Page 17627]]
application of OCATDs for compliance certification is premature.
Without reasonably standardized pressure measuring technology, the
consistency of the OCATDs' performance can not be properly evaluated.
The agency has made provisions in the advanced air bag rulemaking
to allow introduction of new technologies for suppression and the
development of low level deployment activation systems. However, agency
review of the proposed OCATD technology, based on the Alliance report,
indicates that the OCATDs mostly parallel the capabilities of currently
specified Hybrid-III test dummies for measuring seating pressures and
do not provide additional occupant sensing and discrimination
capabilities. The data in the UMTRI technical report indicate that
there is very little potential to develop the OCATDs into better or
more powerful discriminatory tools without substantial further
research. Therefore, it would not be cost beneficial for the agency to
initiate the extensive and expensive process incorporating the OCATDs
into part 572 merely to have them available as parallel surrogates to
the Hybrid-III dummies. However, the agency does not discourage use of
the OCATDs by those vehicle manufacturers who are convinced that OCATDs
will provide them the needed flexibilities for the development of
better functioning suppression systems.
In conclusion, NHTSA denies both parts of this petition for
rulemaking based on lack of compelling evidence that adoption of the
OCATDs into part 572 and their specification in FMVSS No. 208 would
improve the suppression and activation/deactivation of air bag systems
and the safety of the motoring public. Furthermore, the agency has no
plans to conduct research on design and performance of the OCATDs with
the intent purpose either to incorporate them into part 572 or to
specify their use for deployment suppression certification tests in
FMVSS No. 208.
Authority: 49 U.S.C. 30162; delegations of authority at 49 CFR
1.50 and 49 CFR 501.8
Issued on: March 30, 2004.
Claude H. Harris,
Director, Office of Crash Avoidance Standards.
[FR Doc. 04-7546 Filed 4-2-04; 8:45 am]
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