# Federal Motor Vehicle Safety Standards; Occupant Crash Protection

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3A99-28366

## Record

- **Collection:** Federal Register
- **Document type:** Proposed Rule
- **Published:** November 5, 1999
- **Citation:** 64 FR 60556

## Text

SUMMARY: In September 1998, we proposed to upgrade our air bag
requirements for passenger cars and light trucks to meet the twin goals
mandated by the Transportation Equity Act for the 21st Century:
improving protection for occupants of all sizes, belted and unbelted,
in moderate to high speed crashes; and minimizing the risks posed by
air bags to infants, children, and other occupants, especially in low
speed crashes. In response to the public comments on our 1998 proposal
and to other new information obtained since issuing the proposal, we
are issuing a supplemental proposal that updates and refines the
amendments under consideration.
With respect to the goal of improving protection, we are proposing
to adopt one of the following alternative crash tests to evaluate the
protection of unbelted occupants in moderate to high speed crashes,
i.e., those that are potentially fatal. One alternative is an unbelted
rigid barrier test (perpendicular and up to 30 degrees
oblique to perpendicular) with a maximum speed to be established in the
final rule within the range of 40 to 48 km/h (25 to 30 mph). If we
reduce the maximum speed to 40 km/h (25 mph) permanently, we might also
increase the maximum speed of the belted rigid barrier test from the
current 48 km/h to 56 km/h (30 to 35 mph). Another alternative is an
unbelted offset deformable barrier test with a maximum speed to be
established in the final rule within the range of 48 to 56 km/h (30 to
35 mph). The vehicle would have to meet the requirements both in tests
with the driver side of the vehicle engaged with the barrier and in
tests with the passenger side engaged.
With respect to the goal of minimizing the risks of air bags in low
speed crashes, we continue to propose performance requirements to
ensure that future air bags do not pose unreasonable risk of serious
injury to out-of-position occupants. We continue to propose to adopt a
number of options for complying with those requirements so that vehicle
manufacturers would be free to choose from a variety of effective
technological solutions and to develop new ones if they so desire. With
this flexibility, they could use technologies that modulate or
otherwise control air bag deployment so deploying air bags do not cause
serious injuries, technologies that prevent air bag deployment if
children or out-of-position occupants are present, or a combination
thereof.

DATES: You should submit your comments early enough to ensure that
Docket Management receives them not later than December 30, 1999.

ADDRESSES: You may submit your comments in writing to: Docket
Management, Room PL-401, 400 Seventh Street, SW, Washington, DC 20590.
You may also submit your comments electronically by logging onto the
Dockets Management System website at http://dms.dot.gov. Click on
``Help & Information'' or ``Help/Info'' to obtain instructions for
filing the document electronically. Regardless of how you submit your
comments, you should mention the docket number of this document.
You may call Docket Management at 202-366-9324 and visit the Docket
from 10:00 a.m. to 5:00 p.m., Monday through Friday.

FOR FURTHER INFORMATION CONTACT: For information about air bags and
related rulemakings: Visit the NHTSA web site at http://
www.nhtsa.dot.gov and select ``Air Bags'' under ``Popular
Information.''
For non-legal issues, you may contact Clarke Harper, Chief, Light
Duty Vehicle Division, NPS-11. Telephone: (202) 366-2264. Fax: (202)
366-4329. E-mail: [email protected]
For legal issues, you may contact Edward Glancy, Office of Chief
Counsel, NCC-20. Telephone: (202) 366-2992. Fax: (202) 366-3820.
You may send mail to both of these officials at the National
Highway Traffic Safety Administration, 400 Seventh St., S.W.,
Washington, D.C. 20590.

SUPPLEMENTARY INFORMATION:

Note to readers: As an aid to readers who are outside the
engineering community, we have provided at the end of this document
a glossary that briefly explains the key technical terms used in
this preamble. In the case of the term, ``fixed barrier crash
test,'' we have supplemented the explanation with illustrations.
That glossary appears in Appendix B. Interested persons may find it
helpful to review that glossary before reading the rest of this
document.

Table of Contents

I. Executive Summary
II. Background
A. Statutory Requirements
B. Existing Air Bag Requirements
C. September 1998 NPRM
D. Public Comments
1. Tests for Requirements to Improve Occupant Protection for
Different Size Occupants, Belted and Unbelted
a. Belted Rigid Barrier Test
b. Unbelted Rigid Barrier Test
c. Up-to-40 km/h (25 mph) Offset Deformable Barrier Test
2. Tests for Requirements to Minimize the Risk to Infants,
Children and Other Occupants from Injuries and Deaths Caused by Air
Bags
a. Tests to Minimize Risks to Infants
b. Tests to Minimize Risks to Children
c. Tests to Minimize Risks to Adults
3. Injury Criteria
E. Events since September 1998
III. SNPRM for Advanced Air Bags
A. Introduction
B. Existing and Proposed Test Requirements
1. Tests for Requirements to Improve Occupant Protection for
Different Size Occupants, Belted and Unbelted
a. September 1998 NPRM
b. Comments on September 1998 NPRM
c. SNPRM
(i) Requirements for Tests with Unbelted Dummies
(ii) Proposed Array of Crash Test Requirements
(iii) Location and Seating Procedures for 5th Percentile Adult
Female Dummy
2. Tests for Requirements to Minimize the Risk to Infants,
Children and Other Occupants from Injuries and Deaths Caused by Air
Bags
a. Safety of Infants
b. Safety of Young Children
c. Safety of Small Teenage and Adult Drivers
C. Injury Criteria
1. Head Injury Criteria
2. Neck Injury Criteria
3. Thoracic Injury Criteria
4. Lower Extremity Injury Criteria
5. Other Criteria
D. Lead Time and Proposed Effective Date
1. Large Manufacturers
2. Small Manufacturers and Multi-stage Manufacturers
E. Availability of Original Equipment and Retrofit Manual On-Off
Switches
F. Warning Labels and Consumer Information
G. Miscellaneous Issues
1. Selection of Child Restraints
2. Due Care Provision
3. Selection of Options
4. Relationship of Proposed New Injury Criteria to Existing Test
Requirements
5. Time Parameters for Measuring Injury Criteria During Tests
6. Cruise Controls
7. Rescue Operations
8. Assessing Lower Extremity Injury Potential in Offset
Deformable Crash Tests
9. Hybrid III Dummy Neck

[[Page 60557]]

H. Relationship between the NPRM, Comments on the NPRM and this
SNPRM
IV. Costs and Benefits
V. Rulemaking Analyses and Notices
VI. Submission of Comments
Proposed Regulatory Text
Appendix A--Response to Petition
Appendix B--Glossary

I. Executive Summary

Since the early 1990's, NHTSA has been taking steps to reduce the
risk that air bags will sometimes cause deaths, particularly to
unrestrained children and small adults, and to maintain and improve the
benefits of air bags. Our initial efforts to reduce the risks focused
on a public education campaign to alert the public about the dangers of
air bags to children in general and to infants in particular. We urged
parents to place their children in the back seat whenever possible and
to ensure that they were always properly restrained.
Later, to speed the redesigning and recertifying of air bags that
reduce the risks to out-of-position occupants, we established a
temporary option allowing vehicle manufacturers to certify their
vehicles based on an unbelted sled test. The sled test is simpler, less
expensive, and easier to meet than the pre-existing 30 mph unbelted
crash test. Limited available data appear to indicate that these
redesigned air bags have reduced the risks from air bags for the at-
risk populations. However, it is not possible at this time to draw
statistically significant conclusions about this.
There is a greater amount of data on the overall benefits of air
bags. These data indicate that the redesigned air bags \1\ provide
essentially the same protection as that provided by earlier air bags.
We have considered this information in light of agency tests showing
that most of the tested vehicles, although certified to the sled tests,
also passed the more stringent 30 mph unbelted crash test.
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\1\ See footnote 15 for an explanation of the term, ``redesigned
air bags.''
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Manufacturers are developing an assortment of technologies,
commonly referred to as advanced air bag technologies, to reduce the
risks still further, for children, as well as adults. These
technologies include dual-stage inflators which enable air bags to
inflate with two different levels of power and which can be linked to
various types of sensors including those that sense crash severity,
belt use, and seat position (i.e., the location of a vehicle seat on
its track). Occupant weight sensors and pattern sensors can be used to
prevent an air bag from deploying at all in the presence of children.
These advanced air bag technologies are not just hypothetical
possibilities; vehicle manufacturers are beginning to install them in
an increasing variety of vehicles. The MY 1999 Hyundai Sonata has a
weight sensor designed to prevent the passenger air bag from deploying
unless a weight of more than 66 pounds is detected on the passenger
seat. Honda introduced a dual stage inflator in its MY 1999 Acura. The
MY 2000 Ford Taurus and Honda Accord, which are among the highest
selling models in this country, have dual-stage air bags. Some luxury
vehicles also have advanced air bag technologies. For example, Mercedes
and BMW have dual-stage air bags in some of their MY 2000 cars. The MY
2000 Cadillac Seville has weight and pattern sensors in the passenger
seat that work together to turn off the passenger air bag when children
are present.
In the Transportation Equity Act for the 21st Century (TEA 21),\2\
Congress mandated that we issue a final rule that requires the
installation of air bags meeting, by means that include advanced air
bag technologies, two goals: first, improving occupant protection for
occupants of different sizes, regardless of whether they use their seat
belts, and second, minimizing the risk to infants, children and other
occupants of deaths and injuries caused by air bags. In accordance with
TEA 21, we published a proposal in September 1998 to require the timely
introduction of advanced air bags by all vehicle manufacturers and to
establish procedures for testing the risk-reducing capabilities of the
various types and combinations of advanced air bag technologies. Given
the twin goals mandated by TEA 21, the proposal was necessarily both
expansive and complex.
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\2\ The provisions in TEA 21 regarding air bags were contained
in a part called The NHTSA Reauthorization Act of 1998. Given the
greater public familiarity with the name TEA 21, we will refer to
it, instead of the Reauthorization Act, in this document.
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To meet the first goal of improving occupant protection, we
proposed a variety of tests using belted and unbelted dummies. We also
proposed adding a new dummy representing short-statured adult females.
Included in these proposals was a proposal to terminate the unbelted
sled test option so that vehicles with advanced air bags would be
tested in unbelted barrier crashes. The sled test option was valuable
as a short-run expedient to make it easier for manufacturers to bring
redesigned air bags to market quickly. However, for the long-run
purpose of testing air bags to ensure that they are, and that they will
continue to be, effective in protecting people in real world crashes,
the agency tentatively concluded that air bags should be evaluated in
tests simulating those crashes. In particular, the agency proposed to
rely on an unbelted 48 km/h (30 mph) rigid barrier crash test that
approximates many of the real world crashes severe enough to pose
significant risk of serious or fatal injury. Among the tests for belted
occupants was a new 40 km/h (25 mph) offset deformable barrier test
which was intended to evaluate the ability of crash sensors to sense
soft pulse crashes.
With respect to the second goal of minimizing the risks of air
bags, the very breadth of the different technological approaches for
meeting that goal necessitated we make our proposal even more expansive
and complex. We proposed to adopt in the final rule an array of tests
to accommodate these different technological approaches and the
different choices being made by individual manufacturers about which
types of those technologies to adopt. In some cases, we were able to
propose generic tests that are suitable for all advanced air bags. In
other cases, however, we had to propose tests that are tailored to
particular technologies and that would apply to only those air bags
incorporating those technologies. This array of tests was intended to
provide the manufacturers with technology and design flexibility, while
providing the agency with effective means of evaluating the performance
of all of the different advanced air bag systems.
The public comments and the agency research and analysis since our
1998 NPRM have enabled us to refine and in some cases simplify the
proposed amendments that we are considering. In view of the importance
of some of the changes, we have decided to publish this SNPRM to obtain
further public comment before making any final decisions and issuing a
final rule.
We have reduced the number of proposed dynamic and static tests,
especially those relating to the proposed requirements for reducing the
risks of air bags. We have reduced, from 14 to nine,\3\ the number of
proposed dynamic crash tests that would be applicable to all vehicles.
We originally proposed that vehicles equipped with static air bag
suppression systems (e.g., weight sensors and pattern sensors) be
subject to being tested with any child restraint manufactured over a
ten-year period.

[[Page 60558]]

This would have created the possibility of testing with any one of
several hundred different models of child restraints. Recognizing that,
we solicited comments to aid us in identifying a much more limited
number of specific models that would be representative of the array of
available child restraints. Based on the public comments, we are now
proposing to require that vehicles be able to meet the applicable
requirements when tested with any one of a far more limited number of
child restraints representing a cross-section of the restraints
currently on the market.\4\ We have also significantly reduced the
number of positions in which test dummies or child restraints could be
placed for testing a static suppression system. This was accomplished
largely by eliminating positions that were substantially similar to
other positions.
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\3\ The methodology for counting the number of proposed tests is
explained later in this notice.
\4\ For the infant dummy, 19 different seats; for the 3-year-old
dummy, 12 different seats; and for the 6-year-old dummy, 5 different
seats. These figures are not additive since some seats are used for
tests with two different dummies. A total of 24 seats (12 infant
seats, 7 convertible seats, and 5 booster seats) would be used.
---------------------------------------------------------------------------

We are proposing to expressly provide that manufacturers may use
children or small women instead of dummies in static tests to provide a
basis for certifying compliance with the proposed tests for static
suppression systems. These are simple tests in which the vehicle does
not move, and the air bags cannot deploy. We are making this proposal
because existing anthropomorphic test dummies were not designed to
replicate the weight distribution of sitting humans in a manner that
would adequately test all suppression technologies, e.g., pressure/
pattern recognition sensors in the vehicle seat. Since the ultimate
goal of our provisions concerning suppression systems is to achieve
high reliability in detecting the presence of humans, the use of humans
for the simple and limited purpose of testing the static suppression
systems would make good sense. It is unnecessary to propose the use of
infants for certification purposes, since all of the infant restraints
should be detectable by any suppression system, regardless of whether
they are occupied by a dummy or an infant.
We have eliminated the proposed test for dynamic automatic
suppression systems (DASS) and the proposed full scale out-of-position
test including pre-crash braking. Public comments and our further
testing have led us to conclude that these tests would require
enhancements to dummy biofidelity and test procedure development that
we could not complete in time for this rulemaking. Further, the
commenters did not suggest any workable, effective tests that we could
propose as replacements.
Instead, we are taking a different approach that will provide
flexibility to manufacturers that may wish in the future to certify
advanced air bag systems incorporating a DASS to Standard No. 208. We
believe that it is important in crafting our proposals regarding
advanced air bags to facilitate efforts by the manufacturers to develop
new and possibly better ways of reducing air bag risks. Accordingly, we
are proposing to establish very general performance requirements for
DASS and a special expedited petitioning and rulemaking process for
considering procedures for testing advanced air bags incorporating one
of these systems. Target time limits for each phase of such a
rulemaking are proposed. Anyone wishing to market such advanced air
bags could develop test procedures for demonstrating the compliance of
their particular DASS with the performance requirements and submit
those test procedures to the agency for its consideration. If the
agency deems it appropriate to do so after evaluating the petition, the
agency would publish a notice proposing to adopt the manufacturer's
test procedure. After considering those comments, the agency would then
decide whether the procedure should be added to Standard No. 208. If it
decided to do so, and if the procedure were suitable for the DASS of
any other vehicles, then the procedure could be used by those
manufacturers of those vehicles as well as by the petitioning
manufacturer. The agency intends to minimize the number of different
test procedures that are adopted for DASS and to ensure ultimately that
similar DASS are tested in the same way.
We have also decided to change our proposed injury criteria. We
have decided to drop our proposal for a new combined thoracic index
(CTI) and instead maintain separate limits for thoracic acceleration
and deflection.\5\ While CTI may be a better predictor of thoracic
injury than chest acceleration and chest deflection independently,
there is debate in the biomechanics community about the interpretation
of the data. Consequently, we are pursuing further research to resolve
the issues.
---------------------------------------------------------------------------

\5\ The thorax is the chest area.
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We are also proposing to change the existing head injury criterion
(HIC) for the 50th percentile adult male dummy.\6\ HIC is currently
required not to exceed 1,000 and is evaluated over a 36 millisecond
period. We are proposing to evaluate the HIC over a maximum 15
millisecond time interval with a requirement that it not exceed a
maximum of 700. The agency historically has used a 36 millisecond time
interval to measure HIC primarily because this method allowed the HIC
measurement to indirectly capture risk of neck injury (until recently,
a direct indication of neck injury risk was not a part of Standard
208). With the addition of specific neck injury criteria to Standard
208, the agency can switch to a 15 ms measurement interval which better
corresponds to the underlying biomechanical research. We are proposing
to change the HIC time interval to a maximum of 15 milliseconds for all
dummy sizes and to revise the HIC limits by commensurate amounts, based
on a scaling from the proposed new limit for the 50th percentile adult
male dummy.
---------------------------------------------------------------------------

\6\ HIC consists of a formula which utilizes data regarding the
acceleration of the dummy head in vehicle tests to produce a number
to determine compliance.
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We are proposing a neck injury criteria (Nij) limit of 1.0, the
calculation of which has been revised since the NPRM. In the NPRM, we
requested comments on performance limits of Nij=1 and Nij=1.4. After
considering the comments, the available biomechanical data, and testing
which indicates that the more conservative or stringent value of 1.0
can be met in current production vehicles, we are proposing a limit of
1.0. The formulae underlying the calculation of Nij for smaller dummies
incorporate scaling in recognition of the greater susceptibility of
children to injury.
Finally, we are proposing two alternative crash tests for
evaluating the effectiveness of an advanced air bag in protecting
unbelted occupants in a relatively high speed crash. These tests would
be conducted with dummies representing 50th percentile adult males as
well as with ones representing 5th percentile adult females. We
contemplate adopting one of these tests in a final rule, although we
could decide to require elements of both alternatives. We believe that
crashing a complete vehicle into a barrier is needed to address the
type of situation for which air bags are designed: frontal crashes
involving vehicles striking another object with sufficient force that
the impact of an occupant with the steering wheel, dashboard, or other
interior surface could result in severe injuries or death.
The first alternative is an unbelted rigid barrier test
(perpendicular and up to 30 degrees oblique to
perpendicular) with a maximum speed to be established in the final rule
within the range of 40 to 48 km/h (25 to 30

[[Page 60559]]

mph). This alternative is similar to the test included in our 1998
NPRM. The agency's intent in this rulemaking is to maximize, to the
extent consistent with TEA 21, the protection that air bags offer in
crashes potentially resulting in fatal injuries. Thus, the agency's
preference is to establish such a test requirement at as high a
severity as practicable. The 40 km/h (25 mph) lower end of the maximum
test speed range is set forth for comment in this notice to ensure that
commenters address a crash test recommended by the Alliance of
Automobile Manufacturers in late August 1999. If we reduce the maximum
speed to 40 km/h (25 mph) permanently, we might increase the maximum
speed of the belted rigid barrier test from the current 48 km/h to 56
km/h (30 to 35 mph). The increase could go into effect after the TEA 21
phase-in period.
The second alternative is an unbelted offset deformable barrier
test with a maximum speed to be established in the final rule within
the range of 48 to 56 km/h (30 to 35 mph). The vehicle would have to
meet the requirements both in tests with the driver side of the vehicle
engaged with the barrier and in tests with the passenger side engaged.
As in the case of the first alternative, if the agency selected this
second alternative for the final rule, it would establish the maximum
speed at as high a level as practicable, consistent with TEA 21, to
maximize the improvement in occupant protection in potentially fatal
crashes.
Regardless of which unbelted test or tests we ultimately adopt, we
would retain a belted rigid barrier test with a maximum speed of 48 km/
h (30 mph) with both 50th percentile adult male and 5th percentile
adult female dummies during the TEA 21 phase-in period.\7\ Further, we
are continuing to propose an up-to-40 km/h (25 mph) offset deformable
barrier test requirement, using belted 5th percentile adult female
dummies.
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\7\ As noted above, if we permanently reduce the maximum test
speed for the unbelted rigid barrier test to 40 km/h (25 mph), we
might increase the maximum test speed for the belted rigid barrier
test to 56 km/h (35 mph), effective sometime after that phase-in
period.
---------------------------------------------------------------------------

We are also continuing to propose to eliminate provisions which
allow original equipment (OE) and retrofit on-off switches under
specified circumstances. Instead of proposing to phase these provisions
out as advanced air bags are phased in, as proposed in the NPRM, we are
proposing to allow OE and retrofit on-off switches to be installed
under the same conditions that currently apply for all vehicles
produced prior to September 1, 2005, the date by which all vehicles
must have an advanced air bag system. We believe that by that time
consumer confidence in the advanced air bag systems will be
sufficiently strong to remove any desire for a manual on-off switch in
vehicles produced with an advanced air bag.
NHTSA is proposing a replacement for the permanent sun visor label
for vehicles certified as meeting the requirements of this proposed
rule. The label would have new graphics and contain statements
regarding belt use and seating children in the rear seat. In addition,
we are proposing a new temporary label that states that the vehicle
meets the new requirements for advanced air bags. This label would
replace the existing temporary label and include statements regarding
seat belt use and children in rear seats.

II. Background

A. Statutory Requirements

As part of TEA 21, Congress required us to issue an NPRM and final
rule meeting two different, equally important goals:

to improve occupant protection for occupants of different sizes,
belted and unbelted, under Federal Motor Vehicle Safety Standard No.
208, while minimizing the risk to infants, children, and other
occupants from injuries and deaths caused by air bags, by means that
include advanced air bags.

(Emphasis added.) \8\
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\8\ The treatment by this provision of the twin goals and of the
protection of belted and unbelted occupants differs significantly
from the treatment that would have been given them by an earlier
version of this mandate. That earlier version would have established
a hierarchy of priorities, placing minimizing the risks of air bags
above improving the protection they provide, and placing the
protection of belted occupants above the protection of unbelted
occupants.
---------------------------------------------------------------------------

The Act provided that we were to issue the final rule by September
1, 1999. However, if we determined that the final rule could not be
completed by that date, the Act provided that the final rule could be
issued as late as March 1, 2000. Because of the complexity of the
issues and the need to issue this SNPRM, we determined that the final
rule could not be completed by September 1, 1999. Under the Act, the
final rule must therefore be issued by March 1, 2000.
TEA 21 addressed various other issues, including the effective date
for the final rule. A complete discussion of the Act's provisions is
included in the 1998 NPRM. See 63 FR 49961.

B. Existing Air Bag Requirements

Pursuant to a provision in the Intermodal Surface Transportation
Efficiency Act of 1991 (ISTEA), Standard No. 208 requires all passenger
cars and light trucks to provide automatic protection by means of air
bags.\9\
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\9\ TEA 21 is thus the second in a succession of Congressional
acts modifying the Department's 1984 final rule regarding automatic
protection. That final rule mandated automatic protection, but
explicitly provided discretion with respect to the type of automatic
protection (automatic seat belts and air bags), and implicitly
provided discretion with respect to the use of advanced air bag
technologies. ISTEA eliminated the first area of discretion,
mandating the installation of air bags. TEA 21 eliminates the second
area of discretion, mandating the use of advanced air bag
technologies.
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The automatic protection requirements are performance requirements.
The standard does not specify the design of an air bag. Instead, when
tested under specified test conditions, vehicles must meet specified
limits for injury criteria, including criteria for the head, chest and
thighs, measured on 50th percentile adult male test dummies.
Until recently, these criteria limits had to be met for air bag-
equipped vehicles in barrier crashes at speeds up to 48 km/h (30 mph),
both with the dummies belted and with them unbelted. However, on March
19, 1997, we published a final rule providing manufacturers with the
option of certifying the air bag performance of their vehicles with an
unbelted dummy in a sled test incorporating a 125 millisecond
standardized crash pulse instead of in a vehicle-to-barrier crash test.
We made this amendment primarily to expedite manufacturer efforts to
reduce the force of air bags as they deploy.
Under the March 1997 final rule, the sled test option was scheduled
to terminate on September 1, 2001. We believed there was no need to
permanently reduce Standard No. 208's performance requirements, since a
variety of longer term alternatives were available to manufacturers to
address adverse effects of air bags.
The September 1, 2001 termination date for the sled test option was
superseded by a provision in TEA 21. In a paragraph titled
``Coordination of Effective Dates,'' the Act provides that the unbelted
sled test option ``shall remain in effect unless and until changed by
[the final rule for advanced air bags].''

C. September 1998 NPRM

Pursuant to TEA 21, on September 18, 1998, we published in the
Federal Register (63 FR 49958) a notice of proposed rulemaking (NPRM)
to upgrade Standard No. 208, Occupant Crash Protection, to require
vehicles to

[[Page 60560]]

be equipped with advanced air bags that meet new, more rigorous
performance requirements. The advanced air bags would be required in
some new passenger cars and light trucks beginning September 1, 2002,
and in all new cars and light trucks beginning September 1, 2005.
As we explained in that document, air bags have been shown to be
highly effective in saving lives. They reduce fatalities in frontal
crashes by about 30 percent. However, they also sometimes cause
fatalities to infants in rear facing child safety seats and out-of-
position occupants.
In the 1998 NPRM, we presented a full discussion of the safety
issues related to air bags. We also presented a discussion of our
comprehensive plan to address air bag fatalities, which includes
requiring advanced air bags as a long-term solution.
We proposed to add a new set of requirements to prevent air bags
from causing injuries and to improve the protection that they provide
occupants in frontal crashes. There would be several new performance
requirements to ensure that the advanced air bags do not pose
unreasonable risks to out-of-position occupants.
The NPRM gave alternative options for complying with those
requirements so that vehicle manufacturers would be free to choose from
a variety of effective technological solutions and to develop new ones
if they so desire. With this flexibility, they could use technologies
that modulate or otherwise control air bag deployment so deploying air
bags do not cause serious injuries or that prevent air bag deployment
if children or out-of-position occupants are present.
To ensure that the new air bags are designed to avoid causing
injury to a broad array of occupants, we proposed test requirements
using dummies representing 12-month-old, 3-year-old and 6-year-old
children, and 5th percentile adult females, as well as tests
representing 50th percentile adult males. We noted that many of the
proposed test procedures were new, and specifically requested comments
with respect to their suitability for measuring the performance of the
various advanced systems under development.
We also proposed requirements to ensure that the new air bags are
designed to cushion and protect an array of belted and unbelted
occupants, including teenagers and small women. The standard's current
dynamic crash test requirements specify the use of 50th percentile
adult male dummies only. We proposed also to specify use of 5th
percentile adult female dummies in dynamic crash tests. The weight and
size of these dummies are representative of not only small women, but
also many teenagers.
In addition to the existing rigid barrier test, representing a
relatively ``stiff'' or ``hard'' pulse crash in perpendicular tests and
a more moderate pulse crash in oblique tests, we proposed to add a
deformable barrier crash test, representing a relatively ``soft'' pulse
crash. This proposed new crash test requirement was intended to ensure
that air bag systems are designed so that they do not deploy too late.
Some current air bags deploy relatively late in certain types of
crashes. If an air bag deploys too late, normally seated occupants may
move too close to the air bag before it starts to inflate. In such a
situation, the air bag is less likely to protect the occupant and may
pose a risk to the occupant. We proposed to use 5th percentile adult
female dummies in this test.
We also proposed to phase out the unbelted sled test option as we
phased in requirements for advanced air bags. We acknowledged that the
sled test option has been an expedient and useful temporary measure to
ensure that the vehicle manufacturers could quickly redesign all of
their air bags and to help ensure that some protection would continue
to be provided. Nevertheless, we stated that we did not consider sled
testing to be an adequate long-term means of assessing the extent of
occupant protection that a vehicle and its air bag will afford
occupants in the real world.
Finally, we proposed new and/or upgraded injury criteria for each
of the proposed new test requirements, and also proposed to upgrade
some of the injury criteria for the standard's existing test
requirements.

D. Public Comments

We received comments from a wide range of interested persons
including vehicle manufacturers, air bag manufacturers, insurance
companies, public interest groups, academia, and government. Commenters
generally supported the goals mandated by TEA 21--improving the
benefits of air bags, while minimizing risks from air bags--but
expressed widely differing views as to how to accomplish those goals.
In this section of the preamble, we summarize the comments,
particularly those relating to the major issues. Because of the large
number of public comments, we have included a representative sample of
the comments and the commenters who made them.
1. Tests for Requirements To Improve Occupant Protection for Different
Size Occupants, Belted and Unbelted
a. Belted Rigid Barrier Test.
A number of vehicle manufacturers opposed adding a belted rigid
barrier test using 5th percentile adult female dummies. These
commenters argued that this particular test is redundant given the
existing belted barrier test using 50th percentile adult male dummies
and the other proposed tests using 5th percentile adult female dummies.
The comments of the vehicle manufacturers on this issue were
reflective of a more general theme running through their comments,
i.e., they believed the NPRM was overly complex and included too many
tests.
b. Unbelted Rigid Barrier Test.
Commenters had sharply different views on our proposal to phase out
the unbelted sled test option and reinstate the up-to-48 km/h (30 mph)
unbelted rigid barrier test. Many commenters, including all vehicle
manufacturers and the Insurance Institute for Highway Safety (IIHS),
strongly opposed reinstating the unbelted rigid barrier test. These
commenters generally argued that reinstating this test would
necessitate a return to ``overly aggressive'' air bags and that the
test is not representative of typical real world crashes. Vehicle
manufacturers requested that the sled test option remain available for
the long term. On the issue of possible alternative unbelted tests,
IIHS suggested that, if we wish to phase out the sled test, we should
consider replacing it with a 56 km/h (35 mph) offset deformable barrier
test.
On August 31, 1999, however, vehicle manufacturers and their trade
associations, Alliance and AIAM, announced to the agency a recently
reached consensus recommendation for an unbelted crash test. The
industry recommended an unbelted rigid barrier crash test at 40 km/h
(25 mph) using both 50th percentile adult male dummies and 5th
percentile adult female dummies. The test would be conducted in the
perpendicular mode only, i.e., there would be no oblique tests. No
supporting data or written analyses were submitted to the agency at
that meeting.
Other commenters, including a number of advocacy groups, argued
that the up-to-48 km/h (30 mph) unbelted rigid barrier test is
representative of a significant portion of real world crashes, and that
improvements in vehicle and air bag designs will enable manufacturers
to meet the test without

[[Page 60561]]

safety tradeoffs. Public Citizen argued that while the manufacturers
attempt to blame the unbelted barrier test for the deaths and injuries
caused by air bags, a closer examination suggests that manufacturers'
design selection is the real cause of injuries. It further argued that
TEA 21 contemplates that neither belted occupants nor unbelted
occupants be favored under Standard 208 and that both deserve safe and
effective protection by air bags.
c. Up-to-40 km/h (25 mph) Offset Deformable Barrier Test.
Commenters' views on the proposed up-to-25-mph belted offset
deformable barrier test were mixed, but mostly supportive. Many
commenters, including several advocacy groups and a number of vehicle
manufacturers, supported the addition of an offset deformable barrier
test.
Some vehicle manufacturers requested that the test be conducted
only with the driver's side engaged, instead of with either side
engaged as proposed in the NPRM. The Association of International
Automobile Manufacturers (AIAM) stated that a test with the driver's
side engaged would more likely produce ``worst case'' driver out-of-
position locations and possible driver-side intrusion, and that a
passenger side offset test would be redundant. Another suggestion made
by some vehicle manufacturers was to conduct the test only at 40 km/h
(25 mph), rather than at speeds up to 40 km/h (25 mph).
General Motors (GM) stated that it agreed with the addition of the
offset deformable barrier test only if the unbelted sled test option
remained in effect. GM stated that the offset deformable barrier test
augments the sled test by addressing the crash sensing aspects of
performance.
DaimlerChrysler argued that the addition of a 40 km/h (25 mph)
belted offset deformable barrier test for the 5th percentile female is
unnecessary in light of future ``depowered'' and/or advanced air bags.
That commenter stated that injury risks to small occupants sitting near
the driver air bag are adequately assessed using the proposed out-of-
position, low-risk deployment tests, which it endorses.
Some vehicle manufacturers indicated that air bags might be
designed so that they would not deploy in 40 km/h (25 mph) offset
crashes.
2. Tests for Requirements To Minimize the Risk to Infants, Children and
Other Occupants From Injuries and Deaths Caused by Air Bags
a. Tests to minimize risks to infants.
While commenters generally supported adding tests for infant
safety, they raised a number of issues about the proposed tests.
The vehicle manufacturers opposed the proposal to test with any
infant seat manufactured during approximately the 10 years prior to the
date of vehicle manufacture, citing practicability concerns. A number
of vehicle manufacturers also argued that the agency proposed too many
test positions. Commenters raised numerous concerns about the specific
details of the proposed test procedures.
Some commenters suggested that the agency require suppression in
the presence of infants, instead of permitting a low-risk deployment
option as well. These commenters cited uncertainties related to injury
risk for infants and the lack of infant biomechanical data. They
further questioned if there is any benefit from air bag deployments for
infants.
A number of commenters also raised concerns about whether
suppression devices will be ready in time to meet the requirements for
advanced air bags, and how reliable they will be.
b. Tests to minimize risks to children.
Commenters' views on the proposed tests for child safety were
similar to those for infant safety. While supportive of adding tests in
this area, vehicle manufacturers raised concerns about the number of
child restraints, number of tests, and, in some cases, availability of
reliable suppression devices.
A number of commenters raised concerns about whether current child
dummies are sufficiently human-like to be appropriate test devices for
some of the advanced technologies under development. By way of example,
concern was expressed that suppression devices that work by sensing the
distributed weight pattern of a child on a seat may not recognize the
pattern of a test dummy.
Commenters raised numerous technical issues concerning the proposed
options for automatic suppression features that suppress the air bag
when an occupant is out-of-position (S27 of the regulatory text
proposed in the NPRM). Some commenters argued that the proposal to test
automatic suppression features using a moving headform is not
appropriate for some of the devices under development, such as sensors
designed to track the full body of the occupant and not just the head.
Others expressed difficulties related to defining the size, shape, and
orientation of the suppression plane, as well as the maximum response
time of the system.
Commenters also raised numerous technical issues concerning the
dynamic out-of-position test (S29 of the regulatory text proposed in
the NPRM). Some commenters stated that the dummy trajectories resulting
in this test are unrealistic, and that the proposed vehicle crash test
is neither repeatable nor reproducible. Others stated that the dummies
do not move close enough to the air bag prior to deployment to
represent a worst case out-of-position situation.
c. Tests to minimize risks to adults.
Commenters generally supported adding a low-risk deployment test
using a 5th percentile adult female dummy at the driver seating
position, although they raised a number of issues about the proposed
test procedure. GM recommended that the driver low risk deployment test
be made into a component test, outside of the vehicle.
Commenters also raised the same concerns about the proposed options
for automatic suppression features that suppress the air bag when an
occupant is out-of-position (S27) and for the dynamic out-of-position
test (S29) as they did in the context of tests to minimize risks to
children.
GM recommended that the agency also propose a low-risk deployment
test using a 5th percentile adult female dummy at the passenger
position. That company noted that if manufacturers selected the
suppression (presence) option for child safety, there would be no out-
of-position test limiting aggressivity for adult passengers.
3. Injury Criteria
Commenters raised numerous highly technical issues concerning
several of proposed injury criteria and performance limits. Some
commenters questioned the biomechanical basis for certain of the
proposed new injury criteria. The AAMA suggested essentially a
completely revised set of injury criteria.

E. Events Since September 1998

A number of events relevant to this rulemaking have occurred since
publication of the NPRM in September 1998. First, the development of
advanced air bags by suppliers and vehicle manufacturers has continued.
Acura introduced dual stage passenger side air bags in its MY 1999
Acura RL. According to Acura's press release, ``(t)he dual stage air
bags were designed to reduce the inflation speed to help protect
children or small-framed adults. In a low speed collision, the dual-
stage inflator system is triggered in sequence resulting in slower air
bag deployment with less initial force. In

[[Page 60562]]

higher speed collisions, both inflators operate simultaneously for full
immediate inflation. The air bag system logic also controls the
operation of the seat belt pretensioners. A new feature of the system
detects whether the passenger's seat belt is fastened. If the seat belt
is not fastened, the air bag deploys at full force at a lower collision
speed to help offer more protection to the unbelted occupant.''
Ford publicly announced in January 1999 that it will introduce
advanced technology enabling its cars and trucks to analyze crash
conditions and to use the results of the analyses in activating safety
devices to better protect a range of occupants in a variety of frontal
crash situations. Ford stated that its Advanced Restraints System
features nearly a dozen technologically advanced components that work
together to give front-seat occupants significantly enhanced protection
during frontal crashes, taking into account their seating position,
safety belt use and crash severity. That company indicated that
elements of the system, which features technologies such as crash
severity sensors, a driver-seat position sensor, a passenger weight
sensor, safety belt usage sensors, dual-stage inflating air bags,
safety belt pretensioners and energy management retractors, will debut
in vehicles beginning in the 1999 calendar year. Ford stated that the
company will introduce these new technologies on new and significantly
freshened models until all its passenger cars, trucks and sport utility
vehicles have the complete Advanced Restraints System.
GM publicly announced in February 1999 that it will introduce
technology in MY 2000 that is designed to detect the presence of a
small child in the front passenger seat and suppress the deployment of
the passenger frontal air bag in the event of a frontal crash. GM
stated that weight-based sensors, coupled with pattern recognition
technology, will distinguish between a child and a small adult female
whose weight may be similar to a large child restrained in a child
safety seat. If the front passenger seat is occupied by a small child,
whether in a child safety seat or not, GM said that the air bag will
not deploy. GM stated that it will introduce this technology on the
Cadillac Seville in the 2000 calendar year, and that it has a roll-out
plan to extend this technology throughout its product line.
We have received more detailed confidential information from GM and
Ford concerning their plans, as well as confidential information from
other auto manufacturers concerning their latest plans to introduce
various advanced technologies. We have also received confidential
information from suppliers.
Second, in April 1999, we held a public technical workshop
concerning biomechanical injury criteria. The purpose of the workshop
was to provide an additional opportunity for a continuing dialog with
the biomechanics community and the public to assure that we considered
appropriate injury criteria.
Third, we have analyzed the public comments and also conducted
additional testing. We conducted additional tests of current vehicles
with redesigned air bags to determine how they perform in 48 km/h (30
mph) rigid barrier crash tests. We selected vehicles that varied by
class, stiffness, and manufacturer. We also used both 5th percentile
adult female dummies and 50th percentile adult male dummies, belted and
unbelted. We also conducted tests of several current vehicles with
redesigned air bags to determine how they perform in 40 km/h (25 mph)
rigid barrier crash tests, 48 km/h (30 mph) 30 degree right/left
angular barrier tests (belted/unbelted), 56 km/h (35 mph) left/right
side offset fixed deformable barrier crash tests, low speed 24 to 40
km/h (15 to 25 mph) offset deformable crash tests and static out-of-
position tests. We also conducted sled tests at different crash
severities with 95th percentile adult male dummies and MY 1999 and MY
1997 replacement air bags.
Fourth, we have continued to analyze available data to see how
redesigned air bags are performing in the real world. We analyzed 1996
to 1998 Fatality Analysis Reporting System (FARS) data and found
essentially the same number of fatalities in frontal impacts for MY
1996 vehicles in 1996 FARS (730), as in MY 1997 vehicles in 1997 FARS
(776), as in MY 1998 vehicles in 1998 FARS (732). The fatality rates
per million registered vehicles indicate that MY 1996 (56 per million
registered vehicles) had essentially the same fatality rates as MY 1997
vehicles (55), while MY 1998 vehicles had a lower fatality rate (50).
After controlling for safety belt use rates, that is, estimating the
number of fatalities in each year if all three years had the same 1998
usage rate, the fatality rates per million registered vehicles were the
same for MY 1996 and MY 1997 (53), while MY 1998 had a lower fatality
rate (50). Since an estimated 87 percent of MY 1998 vehicles have
redesigned air bags, this suggests that there is essentially the same
or slightly better protection provided by the redesigned air bags
compared to pre-MY 1998 air bags. In assessing the significance of this
information, we will consider the agency tests in which most of the
tested vehicles, although certified to the sled tests, met or exceeded
the historical performance requirements of the 48
km/h (30 mph) rigid barrier crash test.
Another analysis compared the percent of fatalities in frontal
impacts to all impacts for MY 1996 vehicles in calendar year 1996
(38.9%), to MY 1997 vehicles in calendar year 1997 (41.3%), and to MY
1998 vehicles in the first 6-months of calendar year 1998 (39.6%). As
noted above, most of the MY 1998 vehicles have redesigned air bags. No
statistically significant difference was found between the three sets
of data. Again, this implies that the overall protection provided by
the redesigned air bags is essentially the same as that provided by
pre-MY 1998 air bags.
Fifth, on August 31, 1999, and again on September 14, 1999, the
vehicle manufacturers and their trade associations met with the agency
and presented a consensus recommendation for an unbelted crash test.
The industry recommended an unbelted rigid barrier crash test at 40 km/
h (25 mph) using both 50th percentile adult male dummies and 5th
percentile adult female dummies. A letter regarding this recommendation
was received from the Alliance (dated September 2, 1999).\10\
---------------------------------------------------------------------------

\10\ This letter recommended that the agency adopt the following
unbelted barrier test as an alternative to the current unbelted sled
test:
A 40 km/h (25 mph) unbelted rigid barrier, using 5th percentile
adult female dummies and 50th percentile adult male dummies, and the
injury criteria recommended by AAMA in its Dec 98 submission to
agency and endorsed by the Alliance in 1999. The test would be
conducted perpendicularly only at 25 mph (w/ allowance for test
variability) only, not up to 25 mph. The test would be fully phased-
in during TEA 21 phase-in period (MY's 2003-2006). Further, optional
early compliance should be allowed. Upon publication of final rule,
vehicle manufacturers should be allowed to comply with this
recommended test (as opposed to either the sled test or 30 mph
unbelted rigid barrier test), even in the absence of compliance with
requirements intended to reduce the risks associated with air bags.
---------------------------------------------------------------------------

In a letter dated September 16, 1999, an assortment of commenters,
including vehicle manufacturers, vehicle insurers, the American
Automobile Association, the National Automobile Dealers Association,
the American International Automobile Dealers Association, the American
Trauma Society, the National Safety Council, IIHS, and the National
Association of Governors' Highway Safety Representatives, opposed a
return to the 30 mph unbelted rigid barrier test. This letter argued
that a return to this test would require an overall increase in air bag
maximum energy levels with a concomitant increase in risk. No
supporting data or analysis

[[Page 60563]]

accompanied the letter. The letter also urged that NHTSA focus this
rulemaking on reducing the risk of air bags to children and others,
especially in low speed crashes, as compared to the agency's attempting
to increase air bag-related benefits for unbelted occupants in higher
speed crashes.
In a letter dated September 29, 1999, Public Citizen, the Center
for Auto Safety, and Parents for Safer Air Bags stated that they were
``concerned by news reports that a consortium of vehicle manufacturers
and insurers is pressing the agency not to reinstate the 30 mph barrier
crash test for unbelted occupants.'' These organizations argued that
the industry's position is based on the erroneous premise that
protection of unbelted occupants in high-speed collisions causes the
bags to be hazardous to small occupants in low-speed collisions.\11\
They also argued that abandonment of the unbelted 30 mph unbelted test
would obviate the very purpose of the present rulemaking, the
development and introduction of advanced air bags, and result in the
use of generic ``lowest common denominator'' systems that can be
readily be fitted in any vehicle but which seriously compromise safety.
The letter stated that it should not be forgotten that air bags were
originally conceived to protect unbelted occupants in horrific frontal
collisions, and that this remains their principal efficacy to this day.
---------------------------------------------------------------------------

\11\ The letter argued that the safety record of many well-
designed air bag systems over a ten year period belies this premise.
The letter stated that a variety of design features allow for
protection of unbelted occupants in severe crashes without imposing
significant inflation risks in low-speed collisions, and cited
vehicle structures with a longer crash pulse, variable inflation
forces based on crash severity, higher thresholds (including ``dual
thresholds'') and laterally-biased inflation.
---------------------------------------------------------------------------

III. SNPRM for Advanced Air Bags

A. Introduction

Our primary goals in this rulemaking continue to be those set for
us by TEA 21, i.e., to improve occupant protection for occupants of
different sizes, belted and unbelted, while minimizing the risk to
infants, children, and other occupants from injuries and deaths caused
by air bags. Further, we are seeking to ensure that the needed
improvements in occupant protection are made in accordance with the
statutory implementation schedule. After carefully reviewing the
comments on the NPRM and other available information, we have developed
an SNPRM to accomplish these goals.
In developing this SNPRM, we focused on picking the most
appropriate tests so that we could reduce the number of originally
proposed tests without significantly affecting the benefits of the
NPRM. We were persuaded by the commenters that reducing the amount of
testing was important, given resource limitations, and the costs to
manufacturers associated with certifying vehicles to such a large
number of new test requirements. At the same time, we wanted to be sure
that the SNPRM includes sufficient tests to ensure that air bags are
redesigned to meet the goals mandated by TEA 21.
Given the continued debate over what requirements should be relied
upon to ensure protection to unbelted occupants, we also wanted to be
sure that we have considered and received the benefit of public
comments on the various alternative approaches reflecting the views and
information now available to us.
The most significant differences between the NPRM and the SNPRM can
be summarized as follows:
Two alternative unbelted tests. While we proposed one
unbelted test in the NPRM, an up-to-48 km/h (30 mph) rigid barrier
test, we are proposing and seeking comments on two alternative unbelted
tests in this SNPRM. The first alternative is an unbelted rigid barrier
test with a minimum speed of 29 km/h (18 mph) and a maximum speed to be
established within the range of 40 to 48 km/h (25 to 30 mph). Within
this alternative, the potential exists for a phase-in sequence in which
the maximum speed would initially be set at 40 km/h (25 mph) to provide
vehicle manufacturers additional flexibility when they are introducing
advanced air bags during the phase-in. Under this phase-in sequence,
the final rule could provide that a maximum speed of 48 km/h (30 mph)
would apply after a reasonable period of time. If we reduce the maximum
speed to 40 km/h (25 mph) permanently, we might also increase the
maximum speed of the belted rigid barrier test from the current 48 km/h
to 56 km/h (30 to 35 mph). The second alternative is an unbelted offset
deformable barrier test with a minimum speed of 35 km/h (22 mph) and a
maximum speed to be established within the range of 48 to 56 km/h (30
to 35 mph). The latter alternative was developed in response to a
recommendation made by IIHS in its comment on the NPRM.\12\ We are
proposing the 29 and 35 km/h (18 and 22 mph) lower ends of the ranges
of test speeds because we want to be sure that the standard does not
inadvertently create incentives to push deployment thresholds downward,
i.e., cause air bags to be deployed at lower speeds.
---------------------------------------------------------------------------

\12\ IIHS's views have changed since making that recommendation.
Its current views are discussed below.
---------------------------------------------------------------------------

Possible higher speed belted rigid barrier test. We are
also specifically requesting comment on a similar option for the belted
test requirement, in which a 48 km/h (30 mph) test would be in effect
through the TEA 21 phase-in, to be subsequently replaced with a 56 km/h
(35 mph) test, using both 5th percentile adult female and 50th
percentile adult male dummies.
Reduced number of tests. We have significantly reduced the
total number of proposed tests. In a number of situations, we have
tentatively concluded that a proposed test could be deleted because the
performance we sought to secure by means of that test would largely be
assured by one or more of the other tests.
Reduced offset testing. The proposed up-to-40 km/h (25
mph) offset crash test using belted 5th percentile adult female dummies
would be conducted only with the driver side of the vehicle engaged,
instead of both with the driver side and with the passenger side
engaged.
Ensuring that certain static suppression systems can
detect real children and adults. For our proposed static test
requirements for systems (e.g., weight sensors) which suppress air bags
in the presence of infants and children, we are proposing a new option
which would permit manufacturers to certify to requirements referencing
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. Steps would be taken to ensure the safety of all subjects used
for these tests.
Reduced number of child restraints used for testing
suppression systems. Instead of requiring manufacturers to assure
compliance of a vehicle in tests using any child restraint which was
manufactured for sale in the United States any time during a specified
period prior to the manufacture of the vehicle, we would require them
to assure compliance using any child restraint on a relatively short
list of specific child restraint models. Those models would be chosen
to be representative of the array of available child restraints. The
list would be

[[Page 60564]]

updated from time to time to reflect changes in the types of available
child restraints.
Modified requirements for systems that suppress the air
bag for out-of-position occupants. We have significantly modified the
proposed requirements for systems that suppress the air bag when an
occupant is out of position during a crash. In the NPRM, we proposed a
single test procedure for all types of such suppression systems. We
were persuaded by the commenters that the proposed test procedure was
not appropriate for some of the systems that are currently under
development. Because we did not have sufficient information or
prototype hardware to develop a new test procedure, and because no one
test procedure may be appropriate for a number of comparably effective
suppression technologies, we are proposing a provision that would
permit manufacturers or others to petition the agency to establish
technology-specific test procedures under an expedited rulemaking
process.
No full scale dynamic out-of-position test requirements.
We are eliminating from this rulemaking the proposed option for full
scale dynamic out-of-position test requirements (the option which
included pre-impact braking as part of the test procedure). We were
persuaded by the commenters that the proposed test procedure is not
workable at this time. Moreover, we believe this option is unnecessary
at this time, since other options are available for the range of
effective technologies we understand to be under development.
The existing tests that would be retained as well as those proposed
in this SNPRM are identified in Figures 1a, 1b and 2, below. Figures 1a
and 1b show the two alternative sets of test requirements to improve
occupant protection for different size occupants, belted and unbelted,
in moderate to high speed crashes. Figure 2 shows test requirements to
minimize the risk to infants, children, and other occupants from
injuries and deaths caused by air bags, especially in low speed
crashes.

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[[Page 60568]]

A discussion of the specific proposed test requirements follows. We
will first discuss requirements to improve protection for different
size occupants, belted and unbelted, and will then discuss requirements
to minimize risks from air bags. We also discuss in detail the major
differences from the NPRM.

B. Existing and Proposed Test Requirements

1. Tests for Requirements To Improve Occupant Protection for Different
Size Occupants, Belted and Unbelted
a. September 1998 NPRM.
In the NPRM, we proposed test requirements to improve occupant
protection for different size occupants, belted and unbelted. The
proposed requirements included rigid barrier tests and offset
deformable barrier tests.
Under the proposed rigid barrier test requirements in the NPRM,
vehicles would have been required to meet injury criteria performance
limits, including ones for the head, neck, chest, and femurs, measured
on 50th percentile adult male and 5th percentile adult female test
dummies during rigid barrier crash tests at any speed up to 48 km/h (30
mph) and over the range of vehicle-to-crash-barrier angles from -30
degrees to +30 degrees. Tests with 50th percentile adult male dummies
would be conducted with the vehicle seat in the mid-track position;
tests with 5th percentile adult female dummies would be conducted with
the vehicle seats in the full forward position.\13\ Vehicles were to
meet the injury criteria with belted and unbelted dummies. The purpose
of the rigid barrier tests was to help ensure that vehicles protect
different size occupants, belted and unbelted, from risk of serious or
fatal injury in moderate to high speed crashes.
---------------------------------------------------------------------------

\13\ More specifically, the seat would be placed in the full
forward position if the 5th percentile adult female dummy can be
placed in the seat when it is in that position. Otherwise, the seat
is moved back to the closest position to full forward that will
allow the dummy to be placed in the seat.
---------------------------------------------------------------------------

Under the proposed offset deformable barrier test requirements,
vehicles would have been required to meet injury criteria performance
limits during an up-to-40 km/h (25 mph) frontal offset deformable
barrier test, using belted 5th percentile adult female dummies. The
frontal offset test would have been conducted with either the driver
side of the vehicle or the passenger side of the vehicle engaged with
the barrier. The purpose of this test was to help ensure that vehicle
manufacturers design their crash sensing and software systems to
adequately address soft and long duration crash pulses.
Our NPRM would have required as many as a total of 14 crash tests
to improve occupant protection. This number is based on counting each
rigid barrier test specifying use of a particular dummy as three tests,
reflecting the assumption that, for typical vehicle and air bag
designs, there would be three worst case conditions: 48 km/h (30 mph)
at -30 degrees, 48 km/h (30 mph) at 0 degrees, and 48 km/h (30 mph) at
+30 degrees.\14\
---------------------------------------------------------------------------

\14\ The count of 14 tests reflects four rigid barrier tests
(belted 50th percentile adult male dummy, unbelted 50th percentile
adult male dummy, belted 5th percentile adult female dummy, and
unbelted 5th percentile adult female dummy), each of which are
counted as three tests. Thus, the rigid barrier tests account for 12
of the 14 tests. The other two tests were the offset test with the
driver side of the vehicle engaged with the barrier, and the offset
test with the passenger side of the vehicle engaged with the
barrier.
---------------------------------------------------------------------------

Our proposed requirements for improving occupant protection in
potentially fatal crashes differed from the existing Standard No. 208
in several important respects.
First, vehicles would for the first time be required to be
certified to crash test requirements using 5th percentile adult female
dummies, which would be seated in the full forward seat track position.
Historically, the standard has only specified the use of 50th
percentile adult male dummies seated further back.
Second, vehicles would be required for the first time to meet neck
injury criteria performance limits in a crash test. Neck injuries are a
particular concern for persons sitting close to the air bag.
Third, vehicles would for the first time be required to comply with
injury criteria limits in a 40 km/h (25 mph) frontal offset deformable
barrier test with belted 5th percentile adult female dummies. The only
frontal crash tests previously specified by the standard were rigid
barrier tests.
Fourth, we proposed to phase out the unbelted sled test option and
return to the up-to-48 km/h (30 mph) unbelted rigid barrier test
requirement.\15\ However, it would be more than simply returning to the
previous test requirement, since the unbelted rigid barrier test would
now be conducted with 5th percentile adult female dummies as well as
50th percentile adult male dummies. In addition, we proposed added
injury criteria for the chest and neck.
---------------------------------------------------------------------------

\15\ We explained in the NPRM that we added the sled test to
Standard No. 208 in March 1997 as a temporary option to simplify and
expedite the testing and certification of redesigned air bags that
inflate less aggressively. We did so because the lead time needed
for the relatively straightforward redesign measures contemplated by
the manufacturers for MY 1998 vehicles, including the reduction of
inflator power, was significantly shorter than the lead time for the
technological solutions that are the subject of this rulemaking.
---------------------------------------------------------------------------

We proposed to phase out the sled test option as we phased in the
requirements for advanced air bags. We stated that while we believe the
sled test option has been an expedient and useful temporary measure to
ensure that the vehicle manufacturers could quickly redesign all of
their air bags and to help ensure that some protection would continue
to be provided by air bags, we did not consider sled testing to be an
adequate long-term means of assessing the extent of occupant protection
that a vehicle and its air bag will afford occupants in real world
crashes.
We noted that the sled test, first, does not address vehicle
factors that can significantly affect the level of protection provided
in the real world and, second, is not representative of a significant
number of potentially fatal real world crashes. Each of these
limitations is significant. The first means that sled test results may
have limited relationship to real world performance in many types and
levels of severity of crash. The second means that sled test results
may not be a good measure of air bag performance in the kinds of
crashes in which air bags are supposed to save lives. While we proposed
to return to the up-to-48 km/h (30 mph) unbelted rigid barrier test
requirement, we requested comments on possible alternative unbelted
crash test requirements.
b. Comments on 1998 NPRM.
Our proposal to reinstate the up-to-48 km/h (30 mph) unbelted rigid
barrier test requirement was by far the most extensively debated issue
of this rulemaking. As noted earlier, commenters had sharply different
views on this aspect of the NPRM. In their initial comments, motor
vehicle manufacturers and their trade associations strongly opposed
returning to the up-to-48 km/h (30 mph) unbelted rigid barrier test and
urged that the sled test option remain in effect permanently. They
argued that reinstating the up-to-48 km/h (30 mph) unbelted rigid
barrier test would prevent continued use of ``depowered'' air bags and
require a return to ``overly aggressive'' air bags and that the test is
not representative of typical real world crashes. They argued that the
sled test includes a crash pulse that is more representative of typical
real world crashes.
On August 31, 1999, however, vehicle manufacturers and their trade
associations presented to the agency a

[[Page 60569]]

consensus recommendation for an unbelted crash test. The industry
recommended an unbelted rigid barrier crash test at 40 km/h (25 mph)
using both 50th percentile adult male dummies and 5th percentile adult
female dummies. The test would be conducted in the perpendicular mode
only, i.e., there would be no unbelted oblique tests. Industry
representatives argued that oblique tests are not needed to ensure wide
air bags as vehicle manufacturers will provide them in light of other
considerations, e.g., general safety considerations, the 48 km/h (30
mph) belted rigid barrier crash testing, and IIHS and European high
speed belted offset deformable barrier testing.
In its comments on the NPRM, IIHS also opposed returning to the up-
to-48 km/h (30 mph) unbelted rigid barrier test, for reasons similar to
those cited by the vehicle manufacturers. However, that organization
suggested that if we wish to phase out the sled test, we should
consider replacing it with the 56 km/h (35 mph) European offset crash
into a deformable barrier, using unbelted dummies, instead of the rigid
barrier test. IIHS stated that this configuration would address not
only protection in asymmetric crashes, but also some issues of
intrusion that are related to restraint system performance, e.g.,
steering column movement. IIHS also stated that adoption of this test
would be in the direction of harmonizing European and U.S. test
procedures, the only difference being using unbelted versus belted
dummies.
On September 14, 1999, however, IIHS advised us that it now
believes that an unbelted 56 km/h (35 mph) offset deformable barrier
crash test would be inappropriate. That organization is concerned that
including this test in Standard No. 208 might lead to an increase in
unintended high-energy air bag deployments, posing risks to out-of-
position occupants, because of uncertainties in the sensing and
algorithm capabilities in making proper deployment decisions. This
potential problem is related to the nature of this crash test. During
the initial phase of the test, i.e., during the crushing of the
deformable barrier face, vehicles experience a long duration, low
magnitude acceleration. The crash pulse in this phase of the test
resembles that of a low speed crash. After the vehicle crushes the
barrier face and reaches the underlying rigid portion, the remaining
phase of the test is similar to a rigid barrier test. IIHS is concerned
that because the initial phase of the test results in a crash pulse
similar to that experienced in a low speed crash, air bag systems might
not be able to distinguish between the offset test and a low speed
crash during the time the decision whether to deploy the air bag must
be made. If this were the case, an air bag system that was designed to
meet an unbelted 56 km/h (35 mph) offset deformable barrier crash test
by means of a high-energy air bag deployment might inappropriately
provide the same kind of deployment in a low speed crash, thereby
posing unnecessary risks to out-of-position occupants.
The Automotive Occupant Restraints Council (AORC), representing
manufacturers of air bags and seat belts, stated that while it believes
the current sled test option serves a useful purpose, a sled test
cannot provide a complete assessment of the crash protection provided
by a vehicle/restraint system. That organization stated it believes
that to fully assess crash protection for belted and unbelted
occupants, barrier crash tests of complete vehicles should be included
in the test requirements of Standard No. 208. AORC noted that complete
vehicle barrier tests permit the evaluation of the vehicle's structure
and its contribution to occupant protection. AORC recommended that
additional analysis be conducted concerning what barrier and test
conditions should be included in Standard No. 208.
A number of commenters, including several public interest groups,
argued that the up-to-48 km/h (30 mph) unbelted rigid barrier test is
representative of a significant portion of real world crashes, and that
improvements in vehicle and air bag designs will enable manufacturers
to meet the test without safety tradeoffs.
As to the proposed belted tests, some vehicle manufacturers argued
in their comments on the NPRM that a belted rigid barrier test using
5th percentile adult female dummies would be redundant. They argued
that the combination of other tests using 5th percentile adult female
dummies plus the existing rigid barrier test using belted 50th
percentile adult male dummies would address the same area of safety.
Commenters' views on the proposed up-to-40 km/h (25 mph) belted
offset deformable barrier test were mixed, but mostly supportive. Many
commenters, including several safety advocacy groups and a number of
vehicle manufacturers, supported the addition of an offset deformable
barrier test.
As noted earlier, some vehicle manufacturers requested that the
test be conducted only with the driver's side engaged, instead of with
either side engaged as proposed in the NPRM. The Association of
International Automobile Manufacturers (AIAM) stated that a test with
the driver's side engaged would more likely produce worst case driver
out-of-position locations and possible driver-side intrusion, and that
a passenger side offset test would be redundant. Another suggestion
made by some vehicle manufacturers was to conduct the test only at 40
km/h (25 mph), rather than at speeds up to 40 km/h (25 mph).
General Motors (GM) stated that it agreed with the addition of the
offset deformable barrier test only if the unbelted sled test option
remained in effect. GM stated that the offset deformable barrier test
augments the sled test by addressing the crash sensing aspects of
performance.
DaimlerChrysler argued that the addition of a 40 km/h (25 mph)
belted offset deformable barrier test for the 5th percentile adult
female is unnecessary in light of future ``depowered'' and/or advanced
air bags. That commenter stated that injury risks to small occupants
sitting near the driver air bag are adequately assessed using the
proposed out-of-position, low-risk deployment tests, which it endorses.
c. SNPRM.
We believe that the comments on the proposed test requirements to
improve occupant protection for different size occupants, belted and
unbelted, raise two primary questions:
(1) What type and severity level of an unbelted crash test should
be included in Standard No. 208?
(2) Are some of the tests proposed in the NPRM redundant, given the
other proposed tests?
In the sections which follow, we will address what unbelted test
requirements are needed to address the protection of unbelted teenagers
and adults, and what overall set of requirements is needed to improve
protection for different size occupants, belted and unbelted.

(i) Requirements for Tests With Unbelted Dummies

As we address the issue of what unbelted requirements should be
included in Standard No. 208 to address the protection of unbelted
teenagers and adults, we believe the ultimate question for regulators,
industry and the public is how the required safety features work in the
real world. We will consider that question as we separately address two
issues: (1) sled testing versus crash testing, and (2) alternative
unbelted crash tests (e.g., rigid barrier crash tests, offset
deformable tests, etc.) at various severity levels.
Crash testing vs. sled testing. In a full-scale crash test,
instrumented test dummies are placed in a production

[[Page 60570]]

vehicle, and the vehicle is actually crashed. Measurements from the
test dummies are used to determine the forces, and injury potential,
human beings would have experienced in the crash.
Many different types of crash tests can be conducted, and the
various types of crash tests can be conducted at different levels of
severity. Commonly conducted crash tests include: (1) rigid barrier
tests, in which a vehicle is crashed head-on (perpendicular) or at an
angle into a rigid barrier, (2) offset deformable barrier tests, in
which a vehicle is crashed into a barrier with a deformable face, with
only a portion of the front of the vehicle (e.g., 40 percent) engaging
the barrier, and (3) moving deformable barrier tests, in which a moving
deformable barrier designed to be representative of particular vehicles
is crashed into the test vehicle. Vehicle-to-vehicle crash tests, in
which one vehicle is crashed into another vehicle, are sometimes used
in research or product development.
In a sled test, no crash takes place. The vehicle is essentially
undamaged. The vehicle is placed on a sled-on-rails, and instrumented
test dummies are placed in the vehicle. The sled is accelerated very
rapidly backwards (relative to the direction that the occupants would
be facing), so that the occupant compartment experiences the same
motion as might be experienced in a crash. The air bags are manually
deployed at a pre-selected time during the sled test. Measurements from
the test dummies are used to determine the forces, and injury
potential, human beings would have experienced during the test.
In the NPRM, we explained that the agency has long specified full
scale vehicle crash tests using instrumented dummies, in a variety of
our standards, because it is only through such tests that the
protection provided by the vehicle occupant protection system can be
fully measured.
In the NPRM, we cited several significant limitations of the
current sled test, some of which are inherent to any sled test. We
explained:

Unlike a full scale vehicle crash test, a sled test does not,
and cannot, measure the actual protection an occupant will receive
in a crash. The current sled test measures limited performance
attributes of the air bag, but cannot measure the performance
provided by the vehicle structure in combination with the air bags
or even the full air bag system by itself.
Among other shortcomings, the sled test does not evaluate the
actual timing of air bag deployment. Deployment timing is a critical
component of the safety afforded by an air bag. If the air bag
deploys too late, the occupant may already have struck the interior
of the vehicle before deployment begins.
Air bag timing is affected by parts of the air bag system which
are not tested during a sled test, i.e., the crash sensors and
computer crash algorithm. A barrier crash test evaluates the ability
of sensors to detect a crash and the ability of an algorithm to
predict, on the basis of initial sensing of the rate of increase in
force levels, whether crash forces will reach levels high enough to
warrant deployment. However, the sled test does not evaluate these
critical factors. The ability of an algorithm to correctly, and
quickly, predict serious crashes is critical. The signal for an air
bag to deploy must come very early in a crash, when the crash forces
are just beginning to be sensed by the air bag system. A delay in an
air bag's deployment could mean that the air bag deploys too late to
provide any protection. In a sled test, the air bag is artificially
deployed at a predetermined time. The time of deployment in a sled
test is artificial and may differ significantly from the time when
the air bag would deploy during an actual crash involving the same
vehicle.
Second, the current generic sled pulse does not replicate the
actual crash pulse of a particular vehicle model, i.e., the specific
manner in which the front of the vehicle deforms during a crash,
thereby absorbing energy. The actual crash pulse of a vehicle is a
critical factor in occupant protection. A crash pulse affects the
timing of air bag deployment and the ability of an air bag to
cushion and protect an occupant. However, the current sled test does
not use the crash pulse of the vehicle being tested. In many cases,
the crash pulse used in the sled test is not even one approximately
representative of the test vehicle. The sled test uses the crash
pulse of a large passenger car for all vehicles, regardless of their
type or size. This crash pulse is appropriate for large passenger
cars, but not for light trucks and smaller cars since they typically
have much ``stiffer'' crash pulses than that of the sled test. In
the real world, deceleration of light trucks and smaller cars, and
their occupants, occurs more quickly than is simulated by the sled
test. Thus, the sled test results may overstate the level of
occupant protection that would be provided by a vehicle and its air
bag system in the real world. An air bag that can open in a timely
fashion and provide adequate cushioning in a soft pulse crash may
not be able to do so in a stiffer pulse crash. This is because an
occupant of a crashing vehicle moves forward, relative to the
vehicle, more quickly in a stiffer pulse crash than in a softer
pulse crash.
Third, a sled test does not measure the potential for harm from
vehicle components that are pushed back into the occupant
compartment during a crash. Examples of components that may intrude
into the occupant compartment include the steering wheel, an A-
pillar and the toe-board. Since a sled test does not involve any
kind of crash or deformation of the vehicle, it implicitly assumes
that such intrusion does not occur in crashes. Thus, the sled test
may indicate that a vehicle provides good protection when, as a
result of steering wheel or other intrusion, the vehicle will
actually provide poor protection in a real world crash.
Fourth, the sled test does not measure how a vehicle performs in
angled crashes. It only tests vehicles in a perpendicular crash. In
the real world, frontal crashes occur at varying angles, resulting
in occupants moving toward the steering wheel and instrument panel
in a variety of trajectories. The specification of angled tests in
conjunction with the barrier test requirement ensures that a vehicle
is tested under these real world conditions. 63 FR 49971.

Commenters supporting retention of the sled test did not dispute
the inherent limitations of sled tests as compared to crash tests.
AAMA argued that the single best argument for retaining the
existing sled test is that ``it's working;'' AAMA contended that
``depowered'' air bags in vehicles certified according to the sled test
are saving the lives of occupants of all sizes, while reducing the harm
to children and other out-of-position occupants.
It is not clear, however, that the sled test is responsible for any
of the benefits of redesigned air bags other than to the extent it made
it easier for vehicle manufacturers to redesign and certify their
existing air bags more quickly.
As noted earlier, limited available data appear to indicate that
redesigned air bags have reduced the risks from air bags for the at-
risk populations. However, it is not possible at this time to draw
statistically significant conclusions about this. There is a greater
amount of data on the overall benefits of air bags. These data indicate
that there is essentially the same or slightly better protection
provided by the redesigned air bags compared to earlier air bags.
Regardless of how well vehicles with redesigned air bags are
currently performing, however, the sled test itself cannot guarantee
that future air bags would perform nearly so well. These vehicles and
their air bags were initially designed to the unbelted barrier test,
and their current air bags represent quick, partial redesigns of those
air bags. Thus, their performance is still highly reflective of the
unbelted test.
While the sled test has made it easier for manufacturers to
redesign and certify their vehicles more quickly, manufacturers could
and did depower air bags under Standard No. 208's unbelted barrier
test. As discussed below, available data suggest that most vehicles,
while certified to the sled test, continue to meet the unbelted barrier
test requirements (including the new neck injury criteria) with the
50th percentile adult male dummies.
Our goal in this rulemaking is to determine what requirements to
protect

[[Page 60571]]

unbelted and other occupants should apply to vehicles in the future.
AAMA's argument that the sled test is working does not take into
account all of the kinds of less protective vehicles and air bags that
would be permitted by the sled test, given its mildness, and which
might be produced if the sled test were allowed to remain in effect on
a long-term basis.
The sled test is unable to offer any assurance that current
vehicles and air bags are representative of what manufacturers would
offer in the long run if the sled test were available as a permanent
option. Nothing in the standard would inhibit manufacturers from making
their air bags significantly smaller in both depth and width, and thus
less protective in high speed crashes. In particular, narrower air bags
could provide less protection in crashes involving oblique angles. The
sled test also might permit ``face bags'' which do not provide chest
protection or restraint for portions of the lower torso. In addition,
the absence of an unbelted full-vehicle test at an appropriate severity
level would permit vehicles to be designed with stiffer, less energy-
absorbing front ends, e.g., to provide more interior passenger or
cargo-carrying space at the expense of frontal ``crush'' space.
Moreover, unless balanced by an effective unbelted crash test
requirement, the proposed new requirements to minimize air bag risks to
out-of-position occupants have the potential to create an incentive for
manufacturers to make their current air bags smaller and less
protective. An inexpensive and relatively easy way to reduce risks from
the air bag to out-of-position occupants is to further depower air bags
and make them smaller. However, if air bags are depowered too much or
made too small, they will not provide meaningful protection in high
speed crashes.
Our basic obligation is to issue Federal motor vehicle safety
standards that establish a minimum level of performance that protects
the public against unreasonable risk of crashes occurring because of
the design, construction, or performance of a motor vehicle, and
against unreasonable risk of death or injury in a crash. In this
particular rulemaking, we are facing an array of safety problems, and
TEA 21 as well as our pre-existing statutory authority, require that we
address each of them.
The most reliable way to determine how vehicles will perform in
real world crashes is to crash them. That is why we believe that a
crash test is needed. Sled tests are useful research tools, but they do
not provide as full or accurate a measure of the occupant protection
that a vehicle will provide in the real world.
Given the importance of unbelted protection, we believe it is
necessary to provide the public with assurance that the minimum level
of performance for each vehicle will be required to be meaningful,
based on careful scientific and engineering analysis. While we have
carefully considered all of the comments concerning the sled test, we
continue to believe that sled testing is an inadequate long-term means
for ensuring that current levels of unbelted occupant protection are
improved. This is based on the above-noted inherent limitations of sled
tests, as compared to crash tests, in evaluating occupant protection.
Whether one looks at IIHS with its offset crash test program, Europe
with its offset NCAP program, or our experience with our NCAP, Standard
No. 208 and Standard No. 214, it is widely acknowledged that crash
tests, set at appropriate severity levels, provide the best means of
evaluating the protection that occupants will receive in real world
crashes.
For this SNPRM, we urge commenters to focus on what specific
unbelted complete vehicle crash tests are the most appropriate.
Alternative unbelted crash tests. As we noted above, many different
types of crash tests can be conducted, and the various types of crash
tests can be conducted at different levels of severity and orientation.
Commonly conducted crash tests include: (1) fixed rigid barrier tests,
(2) fixed offset deformable barrier tests and (3) moving deformable
barrier tests.
If government or anyone else wants to determine whether a vehicle
provides an appropriate degree of occupant protection in a potentially
fatal or serious injury producing crash, the crash test must have the
severity representative of those crashes. The fact that a test might
indicate that an occupant would not be injured or killed in a
relatively mild crash says nothing about whether the occupant would
likely be killed in a more serious crash. That is why it is important
to distinguish between the universe of all typical real world crashes
and those typical real world crashes serious enough to pose a
significant risk of serious or fatal injury. While one could argue that
the most ``typical'' crash is probably a fender bender resulting in
little or no personal injury, basing Standard No. 208 on such a test
would not result in any savings in lives or reductions in serious
injuries. Of course, there are many issues to consider in selecting a
specific crash test, but we must focus on seeking to represent the kind
of typical crashes that are potentially fatal, rather than typical
crashes as a whole.
When we issued the NPRM, we released a paper titled ``Review of
Potential Test Procedures for FMVSS No. 208.'' The paper provided a
detailed technical analysis of the various alternative crash tests. To
accompany this SNPRM, we are releasing an updated version of that
paper, which has been revised in light of comments and other new
information. The paper shows that, among the currently available
alternative crash tests, the rigid barrier test (perpendicular and up
to 30 degrees oblique to perpendicular) represents the
greatest number of real world crashes involving serious to fatal
injuries. The only alternative crash test that would represent a
greater number of such crashes would be one involving a moving
deformable barrier, which is still undergoing research.
In the NPRM, we noted that while the perpendicular rigid barrier
test results in crash pulses of short duration, e.g., the kind of pulse
that a vehicle experiences when it fully engages another similar-sized
or larger vehicle directly head-on or strikes a bridge abutment, the
oblique rigid barrier tests result in crash pulses of longer duration,
i.e., a ``softer'' crash pulse, which may occur when vehicles strike
each other at various angles.
We also noted that vehicles and air bags designed to comply with
the unbelted rigid barrier test have been effective in saving lives. At
the time of the NPRM, we estimated that air bags had saved the lives of
about 3,148 drivers and passengers. Of these, 2,267 were unbelted. The
rest, 881, were belted. If these levels of effectiveness are maintained
(i.e., 21 percent in frontal crashes for restrained occupants and 34
percent in frontal crashes for unrestrained occupants), air bags will
save more than 3,000 lives each year in passenger cars and light trucks
when all light vehicles on the road are equipped with dual air bags.
Commenters opposing the 48 km/h (30 mph) unbelted barrier test
raised two primary issues. First, they argued that the test is not
representative of typical crashes. Second, they argued that returning
to this test would prevent continued use of ``depowered'' air bags and
would require a return to ``overly aggressive'' air bags.
We note that, in arguing that the 48 km/h (30 mph) unbelted barrier
test is not representative of typical crashes, the commenters did not
define what they meant by ``typical crashes.'' Given that

[[Page 60572]]

the purpose of Standard No. 208 is primarily to reduce serious-to-fatal
injuries, we believe that question is whether that test is
representative of the crashes that produce those injuries. More than
18,000 drivers and right front passengers are killed each year in
frontal impacts, and more than 290,000 drivers and right front
passengers experience moderate to critical non-fatal injuries. These
numbers would be significantly higher without effective air bags.
In order to promulgate safety standards that protect the public
against unreasonable risk of death or injury in a crash, and to fulfill
our specific duty under TEA 21 to improve occupant protection for
occupants of different sizes, belted and unbelted, it is necessary for
Standard No. 208 to address these crashes. In addition, by requiring
vehicles to provide protection over a range of crash severities, e.g.,
in tests at speeds ``up to'' a given velocity, we also address
protection for lower severity crashes. The upper level severity must,
however, be sufficient to ensure that manufacturers provide life-saving
occupant protection in higher speed crashes.
The following figures, derived from National Automotive Sampling
System (NASS) data for years 1993-1997, show the cumulative
distribution of injuries and fatalities in frontal crashes by delta
V,\16\ for all occupants, belted occupants, and unbelted occupants:
---------------------------------------------------------------------------

\16\ As used here, ``delta V'' refers to the crash-induced
change in velocity of a vehicle in a crash. When looking at the
severity of a crash and its influence on air bag design, delta V is
not the only important factor. Another important factor is the time
to reach that delta V. The time is important because it affects the
speed at which the occupant strikes the interior of the vehicle,
i.e., for a given delta V crash, the shorter the time duration, the
higher the occupant impact speed.

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BILLING CODE 4910-59-C
The figures show the cumulative distribution of injuries by delta V
for fatalities, for MAIS 3+ injuries, and for MAIS 2+ injuries. MAIS 3+
injuries are those which are classified as serious or greater injury,
while MAIS 2+ are those which are classified as moderate or
greater.\17\
---------------------------------------------------------------------------

\17\ The AIS or Abbreviated Injury Scale, first developed by the
Association for the Advancement of Automotive Medicine in 1971, is a
consensus-derived, anatomically based system that ranks individual
injuries by body region on a scale of 1 to 6 as follows: 1=minor,
2=moderate, 3=serious, 4=severe, 5=critical, and 6=maximum/currently
untreatable. The AIS is intended as a measure of the severity of the
injury itself and not as a measure of impairments or disabilities
that may result from the injury. It does not assess the combined
effects of multiple injuries to a patient. The AIS was revised and
updated several times, with the most recent revision in 1990. MAIS
represents the maximum injury severity (expressed in terms of AIS)
of any injury received by a person, regardless of the nature or
location of the injury.
---------------------------------------------------------------------------

We can see several things by examining the figures. About 50
percent of fatalities in frontal crashes occur at delta V's below 48
km/h (30 mph), and about 50 percent occur at delta V's above 48 km/h
(30 mph). Looking separately at unbelted and belted occupants, 51
percent of the fatalities involving unbelted occupants and 47 percent
of the fatalities involving belted occupants occur in frontal crashes
at delta V's below 48 km/h (30 mph). We note that the delta V in NASS
represents the speed at which the vehicle would strike a rigid barrier
to duplicate the amount of energy absorbed in the crash. Thus, about
half of fatalities in frontal crashes occur in crashes that are more
severe than a 48 km/h (30 mph) rigid barrier crash, and half of all
frontal crash fatalities occur in crashes that are less severe than a
48 km/h (30 mph) rigid barrier crash. Given that Standard No. 208's
unbelted crash test requirements are intended to save lives, we
disagree that 48 km/h (30 mph) rigid barrier crashes are
unrepresentative of the kinds of crashes in which we are seeking to
ensure protection.
As to the argument that returning to the unbelted 48 km/h (30 mph)
rigid barrier test would prevent continued use of ``depowered'' air
bags and require use of ``overly aggressive'' air bags, the agency will
have to consider the information available to it in making a final
decision.\18\
---------------------------------------------------------------------------

\18\ It is difficult to respond to the industry argument that
the 48 km/h (30 mph) barrier test would prevent continued use of
``depowered'' air bags because ``depowered'' is an amorphous,
relative concept, not an absolute one. The term simply means ``less
power than before.'' Saying that an air bag is depowered is not a
statement that the air bag has more or less than some specific
pressure rise rate or overall peak pressure of the air bag inflator.
Thus, there is no way of examining or testing an air bag to
determine whether it is ``depowered.''
Further, not all pre-depowered air bags had the same level of
power. Indeed, there was a wide variation in the level of power of
pre-depowered air bags. Likewise, there is variation in the level of
power of depowered air bags. In addition, Parents for Safer Air Bags
(Parents) noted that many of today's vehicles incorporate a whole
array of air bag design improvements, making it difficult to
attribute the apparent decrease in air bag fatalities and injuries
to any particular feature or combination of features.
Accordingly, in this document, we generally use the term
``redesigned'' in referring to air bags that have been changed in
various ways since MY 1997, including, in many cases, a reduction in
the pressure rise rate and/or overall peak pressure of the air bag
inflator. These air bags have not been depowered as much as the sled
test permits. Further, most of the redesigned air bags tested by the
agency meet the unbelted 48 km/h (30 mph) barrier test.
---------------------------------------------------------------------------

In the NPRM, we noted that, based on very limited data, it appeared
that many, perhaps most, vehicles with redesigned air bags continue to
meet the historical 48 km/h (30 mph) rigid barrier requirements of
Standard No. 208 (using 50th percentile adult male dummies and applying
the current injury criteria performance limits) by fairly wide margins.
At that time, we had tested five vehicles with redesigned driver air
bags in unbelted 48 km/h (30 mph) rigid

[[Page 60576]]

barrier tests, and all passed Standard No. 208's previous injury
criteria by significant margins. We had tested six vehicles with
redesigned passenger air bags in unbelted 48 km/h (30 mph) rigid
barrier tests, and all but one passed the standard's injury criteria
performance limits by significant margins.
Some vehicle manufacturers objected to our analysis in this area.
They argued that, given the variability associated with testing
different vehicles of the same design, the fact that a particular
vehicle had passed a single test would not necessarily allow them to
certify that model vehicle as complying with Standard No. 208 because
there would not be a sufficient margin of compliance to ensure that all
vehicles of that model would pass the test. Some manufacturers
indicated that they need a 20 percent margin of compliance in order to
so certify. Vehicle manufacturers also stated that they need to ensure
that all variations and configurations of a model would pass the test
and that, in some cases, we tested a configuration which would result
in lower injury criteria readings than other variations and
configurations.
We continue to believe that a key way of assessing the validity of
the argument that a return to the 48 km/h (30 mph) barrier test would--
at least in the absence of additional technological improvements--
prevent continued use of redesigned air bags is to test vehicles with
those air bags in 48 km/h (30 mph) barrier tests and see how they
perform. Therefore, since issuing our NPRM, we have conducted more
barrier tests of vehicles with redesigned air bags.
We have now tested a total of 13 MY 1998-99 vehicles with
redesigned air bags in a perpendicular rigid barrier crash test at 48
km/h (30 mph) with unbelted 50th percentile adult male driver and
passenger dummies. The vehicles represented a wide range of vehicle
types and sizes. In particular, the 13 vehicles included one sub-
compact car, one compact car, four mid-size cars (representing high
sales volume vehicles), one full-size car, two mid-size sport utility
vehicles, one full-size sport utility vehicle, one pickup truck, one
minivan, and one full-size van.\19\
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\19\ The specific vehicles and their classes included a Saturn
(sub-compact car), a Neon (compact car), an Intrepid, Camry, Taurus,
and Accord (mid-size cars), an Acura RL (full-size car), an Explorer
and Cherokee (mid-size SUV's), an Expedition (large SUV), a Tacoma
(pickup truck), a Voyager (minivan), and an Econoline (full-size
van).
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For the driver position, 12 of the 13 vehicles passed all the
relevant injury criteria performance limits we are proposing in this
SNPRM. In the one vehicle with a failure, the MY 1999 Acura RL, the
driver dummy exceeded the femur load criteria. For the passenger
position, 12 of the 13 vehicles also passed all of the relevant injury
criteria performance limits. The MY 1998 Dodge Neon slightly exceeded
the 60 g chest acceleration limit (with a value of 61.4 g). The other
proposed injury criteria performance limits, (i.e., for HIC, chest
deflection, and Nij) were easily met in all the tests; for most there
was a greater than 20 percent margin of compliance for both the driver
and passenger.
Thus, the tested vehicles with redesigned air bags, ranging widely
in vehicle type and size, appear to continue to meet Standard No. 208's
48 km/h (30 mph) unbelted rigid barrier test requirements for 50th
percentile adult male dummies, many of them by wide margins.
As to any vehicles that do not meet that test, at this point we
simply note that TEA 21 affords lead time before all vehicles must meet
whatever tests are incorporated in the final rule to be issued in this
rulemaking.
As to the issue of margin of compliance, we agree that
manufacturers need to ensure that all of their vehicles meet a test
requirement established by a Federal safety standard. However, we do
not agree that this means a 20 percent margin of compliance is
necessary. The chest g value is the injury criterion that is most
likely to be the limiting factor in certifying to the 48 km/h (30 mph)
unbelted rigid barrier test requirements for the 50th percentile adult
male dummy. Examination of compliance and certification data for pre-
redesigned air bags shows that manufacturers often certified vehicles
to the requirement with much less than a 20 percent margin of
compliance. In fact, margins of compliance for our 48 km/h (30 mph)
tests of vehicles with redesigned air bags were not that different from
those with pre-redesigned air bags.
We are not suggesting that every current production vehicle would
comply with the unbelted 48 km/h (30 mph) rigid barrier test. Instead,
we are pointing out that a wide ranging sample of vehicle types and
sizes meet the 48 km/h (30 mph) rigid barrier test, for 50th percentile
adult male dummies, with redesigned air bags.
However, the ultimate issue of this rulemaking is not whether some
MY 1998-99 vehicles with redesigned, single-inflation level air bags
currently would not meet the 48 km/h (30 mph) unbelted barrier test
requirement. As noted above, many of the air bags in current vehicles
were not comprehensively redesigned, but are merely older designs of
air bags with less power. TEA 21 mandates the issuance of a final rule
based on means that include advanced air bag technologies. We believe
the selection of future compliance tests under TEA 21 must be made in
the context of those technologies, and not in the context of today's
less sophisticated one-size-fits-all air bag designs. Today's air bag
systems are not advanced air bags and thus do not respond to factors
such as crash severity, occupant weight and occupant location. By
contrast, the incorporation of advanced technologies would make air bag
systems responsive to those factors. If a manufacturer decided to use a
somewhat more powerful air bag to meet a 48 km/h (30 mph) unbelted
rigid barrier test, or to provide protection in more severe crashes,
the manufacturer could use advanced air bag technologies to provide
less powerful levels of inflation in lower severity crashes, for
smaller occupants, for belted occupants, and for occupants sitting with
the seat in the full-forward position. Manufacturers could also reduce
aggressivity of air bags by various means such as optimizing fold
patterns, different cover designs, lighter fabrics, etc. Advanced
technologies would also enable the manufacturer to suppress air bag
deployment in appropriate circumstances, such as when children are
present.
As we assess the type and severity level of an unbelted crash test
should be included in Standard No. 208, we recognize that we must bear
in mind that the issue of the suitability of a unbelted 48 km/h (30
mph) rigid barrier test cannot be determined solely based on whether
manufacturers can meet that test with redesigned air bags using 50th
percentile male dummies. In the NPRM, we proposed not only to return to
that test requirement, but also to require vehicles to be certified to
several new crash test requirements and new injury criteria performance
limits, including tests using 5th percentile adult female dummies in
the full forward seat track position, and to requirements to minimize
air bag risks. Vehicle manufacturers commented that some of the design
options that are available in redesigning their air bags involve
potential trade-offs in meeting the different proposed requirements.
For example, the optimum size air bag for meeting test requirements for
50th percentile adult dummies may make it more difficult to meet
requirements for 5th percentile adult female dummies,

[[Page 60577]]

and vice versa. This issue, and the agency's testing of current
vehicles to a variety of the proposed test requirements, are discussed
later in this notice.
Proposed alternative unbelted crash tests. In the NPRM, we
indicated that while we believe the 48 km/h (30 mph) unbelted rigid
barrier test is a good approach, we were also willing to consider
alternative unbelted crash tests. The only alternative unbelted crash
test advocated by a commenter that could realistically be implemented
within the time frame of this rulemaking is the unbelted 56 km/h (35
mph) offset deformable barrier test suggested by IIHS. As noted
earlier, IIHS stated that this configuration would address not only
protection in asymmetric crashes but also some issues of intrusion that
are related to restraint system performance, e.g., steering column
movement.
Given the continued debate over what requirements should apply to
ensure protection to unbelted occupants, we want to be sure that we
have considered and received the benefit of public comments on the
various alternative approaches that are available at this time. One
approach, of course, is the one we proposed in the NPRM, the unbelted
rigid barrier test. We note that some have suggested that, instead of
conducting this test at speeds up to 48 km/h (30 mph), we reduce the
maximum speed. Ford, for example, suggested in 1995 that we adopt an
upper speed of 40 km/h (25 mph). It coupled this suggestion with the
further suggestion that the speed of the belted test be increased to 56
km/h (35 mph).\20\ In its recent consensus statement, the Alliance has
suggested a single speed test (perpendicular impact only) of 40 km/h
(25 mph).
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\20\ The agency examined Ford's recommendation in a status
report titled ``On the Issue of Testing Air-Bag Equipped Vehicles
with and without Belt Restraints at Different Speeds,'' November 2,
1995. Originally docketed in the docket (No. 74-14; Notice 97-001)
for a request for comments published by the agency November 9, 1995
(60 FR 56554); more recently docketed in NHTSA-96-1772-002. In the
1995 request for comments, the agency said:
While NHTSA anticipates that these smart bag systems will
substantially minimize adverse side effects of air bags in the not
too distant future, this still leaves the question of what can be
done in addition to public education for the near future.
Manufacturers may be able to make adjustments to existing air bag
systems. Further, NHTSA may be able to make temporary adjustments to
its regulations if it is shown to be necessary to enable
manufacturers to minimize any adverse side effects during this
period.
For example, Ford has requested that NHTSA amend its crash
testing procedures in Standard No. 208. The standard currently
requires test dummies to be protected in a 30 mile per hour (mph)
crash both when wearing safety belts and when not wearing the belts
(i.e., protected by the air bag alone). Ford asked that the test
speed for the unbelted dummies be lowered to 25 mph, while the test
speed for the belted dummies be raised to 35 mph. According to Ford,
this change would allow manufacturers to better ``tune'' the
interaction between the air bag and the safety belt so as to
optimize the protection afforded to occupants who use their belts.
Ford stated that the current testing procedure forces manufacturers
to base occupant protection designs solely on the air bag, rather
than the interaction between the air bag and the belt. Ford believes
that such a change can reduce air bag-induced injuries.
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A second possible approach is an unbelted fixed offset deformable
barrier test, along the lines suggested by IIHS in its comment on the
September 1998 NPRM. While, as discussed above, that organization has
recently identified some concerns about that test, we believe an
unbelted offset deformable barrier test represents a sufficiently
interesting alternative approach to warrant seeking public comment. As
to the concern that IIHS recently identified about air bag systems
possibly having difficulty distinguishing between the offset test and a
low speed crash during the time the decision whether to deploy the air
bag must be made, we note that it may be possible to address this
potential problem by using advanced sensing systems. That is one of the
issues for which we would like to receive public comments. By
requesting public comments, we will obtain additional data and views to
better enable us to make a thorough evaluation of the merits of
including such a test in Standard No. 208.
For this SNPRM, we are proposing and seeking comments on two
alternative unbelted tests. The first alternative is the unbelted rigid
barrier test (perpendicular and up to 30 degrees oblique to
perpendicular with 50th percentile adult male dummies, but
perpendicular only in tests with 5th percentile adult female dummies)
with a maximum speed to be established within the range of 40 to 48 km/
h (25 to 30 mph). As part of this alternative, we are considering the
possibility of coupling a lower speed for the unbelted barrier test
with a higher speed for the belted barrier test. The second alternative
is an unbelted offset deformable barrier test with a maximum speed to
be established within the range of 48 to 56 km/h (30 to 35 mph). A
vehicle would have to meet the requirements both in tests with the
driver side of the vehicle engaged with the barrier and in tests with
the passenger side engaged.
We note that, in considering a range of upper severity levels, the
upper severity level could be adjusted by either changing the test
speed or applying different injury criteria limits at higher speeds.
For example, in our rulemaking to facilitate quick redesign of air
bags, in lieu of the sled test, we identified the possibility of
maintaining the 48 km/h (30 mph) unbelted rigid barrier test, but
relaxing the limit on chest g's. We also note the possibility of
specifying relaxed injury criteria performance limits or lower maximum
test speeds that would apply during the TEA 21 phase-in period and more
stringent ones that would apply thereafter.
For all of the unbelted crash tests proposed in this document,
protection would be required in crashes ranging from a specified
minimum speed to a specified highest speed, rather than at all speeds
``up to'' that specified highest speed.
Under the unbelted rigid barrier test alternative, the agency would
not test at a speed of less than 29 km/h (18 mph), and under the
unbelted offset deformable barrier test alternative, the agency would
not test at a speed of less than 35 km/h (22 mph). (We are proposing a
higher minimum test speed for the latter alternative because, for a
given speed, it is a less severe test.) This is a departure from the
proposal in the NPRM and from prior agency practice. One reason for
this change is that we want to be sure that the standard does not push
deployment thresholds downward, i.e., cause air bags to be deployed at
lower speeds than are appropriate for maximum occupant protection.
Commenters indicated that, in order to meet neck injury criteria, air
bag deployments might be required at very low speeds, even in crashes
with a delta-V lower than 10 mph, particularly with the 5th percentile
adult female dummy in the full forward position. While the issue of the
most appropriate threshold for air bag deployment is complex, we
believe there is a consensus that ``no fire'' thresholds should not be
any lower than they are at present. Moreover, neck injuries are not a
significant problem in lower speed crashes.
The proposed high speed unbelted offset deformable barrier test
would involve the same crash configuration as we proposed in the NPRM
for the up-to-40 km/h (25 mph) belted offset deformable barrier test.
Vehicles would have to meet the requirements in tests with both the
vehicle and the passenger side of the vehicle engaged. The test would,
of course, be conducted at higher speeds, and unbelted 50th percentile
adult male dummies and 5th percentile adult female dummies would be
used.

[[Page 60578]]

The offset deformable barrier test is used in several ways in
different parts of the world. The test has been adopted as a
requirement in Europe at a speed of 56 km/h (35 mph), using belted 50th
percentile adult male dummies, pursuant to EU Directive 96/79 EC. The
test is also conducted in Europe at a higher speed, 64 km/h (40 mph),
as part of the European New Car Assessment Program. The Australian New
Car Assessment Program conducts the same test at the same speed. IIHS
also conducts this test at the same speed, using belted 50th percentile
adult male dummies to evaluate the crashworthiness of vehicles.
Transport Canada is developing a test procedure using belted 5th
percentile adult female dummies at impact speeds up to 40 km/h (25 mph)
to evaluate air bag sensor performance and air bag aggressivity.
While a great deal has been written on the subject of unbelted
rigid barrier tests over the years, the high speed unbelted offset
deformable barrier test is relatively new. We note that we have been
conducting research for several years with the intention of proposing
to add a high speed belted frontal offset test to Standard No. 208. For
information about this research program, see our Report to Congress,
Status Report on Establishing a Federal Motor Vehicle Safety Standard
for Frontal Offset Crash Testing, April 1997. This report is available
on our web site at http://www.nhtsa.dot.gov/cars/rules/CrashWorthy/
offrt.html.
In our Report to Congress, and in the NPRM (63 FR 49958, at 49960),
we stated that we were considering adding the European high speed
belted frontal offset test to Standard No. 208 as a supplement to the
existing tests. We stated in the Report that the Standard No. 208 rigid
barrier test is most effective in preventing head and chest injuries
and fatalities, but noted that it does not address lower limb and neck
injuries.
We stated further in the Report that while the frontal rigid
barrier test of Standard No. 208 does not produce the vehicle intrusion
observed in many real world crashes, it does depict those impacts which
produce the

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A99-28366. Public record. Not legal advice.