Federal Motor Vehicle Safety Standards; Occupant Crash Protection

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.

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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.

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\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.

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\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.

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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.

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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\

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\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.

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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.

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\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.

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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\

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\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.

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\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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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\

---------------------------------------------------------------------------

\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).

---------------------------------------------------------------------------

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).

---------------------------------------------------------------------------

\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.

---------------------------------------------------------------------------

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 highest risk of serious to fatal injuries resulting from

frontal crashes. We stated that the European frontal test procedure

does not address the highest risk of serious to fatal injuries

occurring in frontal crashes and that, from our viewpoint, the European

test conditions were not acceptable as an alternative to Standard No.

208. We stated, however, that adoption of the European test could yield

benefits in terms of a reduction in lower limb injuries.

While our analysis of the European test was made in the context of

a belted condition, it nonetheless raises the issue of whether the test

is adequately representative of potentially fatal crashes. To address

this issue, we have sought to compare the 56 km/h (35 mph) offset

deformable barrier crash test recommended by IIHS to a 48 km/h (30 mph)

rigid barrier test.

Among other things, we have conducted 56 km/h (35 mph) offset

deformable barrier crash tests on MY 1999 Dodge Intrepid and Toyota

Tacoma vehicles. Comparing the crash pulses for these tests with the

pulses of 40 and 48 km/h (25 and 30 mph) rigid barrier tests that we

also conducted using these vehicles, we can make several observations.

For each vehicle, there is a long duration, low magnitude acceleration

during the initial phase of the test that is associated with the

crushing of the deformable barrier face. After the crushing of the

barrier face, the remaining segment of the crash pulse is similar to

that for the 40 and 48 km/h (25 and 30 mph) rigid barrier tests, and

this portion of the acceleration profile generally would fall in

between the pulses for those two rigid barrier tests if adjusted with a

time shift.

A close look at these pulses suggests that, from the perspective of

delta-V, the deformable barrier test is approximately equal in severity

to a 45 km/h (28 mph) rigid barrier test. This is consistent with a

rule of thumb within the research community that the offset test's

barrier equivalent velocity is approximately 20 percent less than the

impact speed.

This observation is also supported by findings from our Advanced

Frontal Research Program. We provided a number of vehicles tested in

both collinear and oblique offset tests to NASS investigators for

analysis. The investigators estimated delta Vs that were substantially

lower than the impact speeds.\21\ Also, IIHS conducted a similar study

and observed similar results,\22\ i.e., the range of delta Vs were 15

to 28 percent lower than the impact speeds.

---------------------------------------------------------------------------

\21\ Stucki, Sheldon L. and Fessahaie, Osvaldo, ``Comparison of

Measured Velocity Change in Frontal Crash Tests to NASS Computed

Velocity Change,'' SAE Paper No. 980649, 1991 SAE International

Congress and Exposition, Detroit, March 1998.

\22\ O'Neill, Brian, Preuss, Charles A., and Nolan, James M.,

Insurance Institute for Highway Safety, ``Relationships Between

Computed Delta V and Impact Speeds for Offset Crashes'', Paper No.

96-S9-O-11, Proceedings of Fifteenth International Technical

Conference on the Enhanced Safety of Vehicles, Melbourne, Australia,

May 1996.

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It is important to note that although we estimate 45 km/h (28 mph)

as the rigid barrier equivalent speed for the 56 km/h (35 mph) offset

deformable barrier test, this does not mean that air bags designed to

meet the 56 km/h (35 mph) offset deformable barrier test would provide

a level of protection equivalent to that provided by air bags designed

to meet a 45 km/h (28 mph) barrier-like crashes.

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.

As discussed in the test procedures paper, the offset crash test

has a long duration deceleration pulse. As a result, occupants in a

vehicle involved in such a crash would impact the interior components

at lower speeds than occupants who were in a vehicle involved in

barrier-like crashes. Because of this aspect of offset crashes, the

test procedures paper separates the crash events in NASS and estimates

a substantially lower target population for the offset test than for

the rigid barrier test.

The high speed unbelted rigid barrier test and the high speed

unbelted offset deformable barrier test are significantly different,

and each has potential advantages as compared to the other.

Among the considerations that are relevant to the high speed

unbelted rigid barrier test are the following--

It involves a stiffer crash, thereby promoting the design

of soft frontal structure and deeper air bags that provide more

protection against AIS 3, life-threatening, head/chest

injuries in higher speed crashes.

It promotes the design of wider air bags which provide

head and chest protection in the angular component of the test.

It is a well known test condition. It has been part of

Standard No. 208 since 1984.

It may result in more repeatable test results than an

offset test would provide. Since the offset test involves striking a

soft structure, there may be a chance of air bag sensor timing

variability. Variations in air bag sensor timing can lead to variations

in occupant kinematics. The rigid barrier test, on the other hand,

results in relatively consistent air bag deployment timings.

The full frontal rigid barrier test represents a vehicle

striking a like vehicle.

Among the considerations that are relevant to the high speed

unbelted

[[Page 60579]]

offset deformable barrier test are the following:

It provides a more challenging test of the vehicle crash

sensors. In order to provide optimal protection to the occupant in a

crash, the crash sensors need to make a determination of when to fire

the air bag as early as possible. However, the challenge in an offset

deformable barrier crash test arises from the fact that the engagement

of the offset deformable barrier results in a soft crash pulse which

needs to be detected by the sensor for the algorithm to make the

decision to deploy, and a harder crash pulse later in the event.

It provides a more challenging test of the vehicle

structure. The offset deformable barrier test engages only 40% of the

front structure of the vehicle. Therefore, the crush is concentrated on

one side and produces more intrusion into the occupant compartment. The

full frontal rigid barrier test engages the entire front of the vehicle

in a distributed loading pattern.

It has greater potential for benefits related to injury

from intrusion.

The deformable barrier is known and used in other test

configurations. The European offset crash test requirement and the IIHS

crashworthiness evaluations are two examples.

The deformable barrier can be bottomed out by sports

utility vehicles and full size pick-up trucks due to their increased

mass and stiffness of the structures involved. To the extent that the

deformable barrier is bottomed out, it becomes more like an offset

rigid barrier test, thereby potentially providing a more severe crash

test for larger, heavier vehicles.

The offset deformable barrier test is not representative

of a vehicle-to-vehicle crash. It is perhaps most easily understood by

comparing it to a full frontal rigid barrier test and an offset rigid

barrier test. An offset rigid barrier test simulates a crash where the

entire crash energy is absorbed by the structural members of the struck

side. In an offset deformable barrier test, this energy is shared by

the barrier and the vehicle structures. Comparing a full frontal rigid

barrier test to an offset rigid barrier test conducted at the same

speed, there is greater likelihood of intrusion. The crash pulse for

the offset rigid barrier test would likely have about the same peak

acceleration but a longer time duration. An offset deformable barrier

test at the same speed would likely result in a lower peak acceleration

and about the same time duration as the rigid offset barrier test.

Comparing a 35 mph offset test to a 30 mph full frontal

rigid barrier test, the peak g's are likely to less in the offset test,

and the time duration of the crash pulse is likely to be substantially

longer.

As noted above, the concept of a high speed unbelted offset

deformable barrier test is new, so there are very few available data

for this test. However, we have tested two vehicles, the MY 1999 Toyota

Tacoma and Dodge Intrepid, in unbelted 56 km/h (35 mph) offset tests

using both 50th percentile adult male and 5th percentile adult female

test dummies. One vehicle, the Tacoma, was able to meet the proposed

injury criteria performance limits without difficulty (for both types

of dummies and both left and right impacts), while the other vehicle,

the Intrepid, had difficulty, particularly with the Nij injury criteria

performance limits. Of course, neither of these vehicles was designed

with the offset test in mind, so these tests have little relevance to

the issue of whether vehicles could satisfy such a requirement.

Some vehicle manufacturers have expressed concerns about an

unbelted high speed offset test. GM has expressed concern about the

ability of vehicle sensing systems to be able to sense the soft,

deformable barrier face of the offset deformable barrier, and still be

able to perform well in real world crashes. According to that company,

its review of actual vehicle data traces plotting deceleration over

time indicates that the frontal offset barrier impact initially looks

much like a low speed crash, where no air bag or just a first stage air

bag might be used. Because of this, a sensor system might not recognize

until well into the crash that the vehicle is undergoing a higher

speed, severe crash. GM believes that if this test were made a part of

the standard, manufacturers would either have to design their sensors

to fire any time they see a lower speed, soft impact, which would cause

more low speed deployments, or design the sensors to optimize for real

world crashes and risk failing this performance test in the standard.

Honda expressed concern about the similarity in pulses between the

40 km/h (25 mph) offset deformable barrier and the 56 km/h (35 mph)

offset deformable barrier crashes. In an August 26, 1999 comment

submitted to the docket, Honda stated that, even though these tests are

dissimilar in terms of ultimate severity, the crash pulses looked

similar during the initial decision period of up to 30 ms. This in part

reflects the fact that the initial phase of the test is measuring the

deformation of the soft barrier. According to Honda, the vehicle's

analytical system will be unable to discern the crash severity and will

not be able to accurately predict what stage to fire, or even whether

to fire the air bag in a timely fashion. That company indicated that

this may result in poor algorithm design.

For additional analysis of the two alternative unbelted tests,

readers are referred to the aforementioned paper and supplement

prepared by our Office of Vehicle Safety Research concerning potential

test procedures for Standard No. 208 and to the Preliminary Economic

Assessment which accompanies this SNPRM.

It is important to note that, whatever unbelted test is included in

Standard No. 208, manufacturers will be required under the final rule

to certify all of their vehicles to a wide variety of new test

requirements, and in a very short period of time. The analysis we

presented earlier in this document concerning how many vehicles

currently appear to meet the 48 km/h (30 mph) unbelted rigid barrier

requirements for 50th percentile adult male dummies was intended to

address the allegation that a return to the test would prevent

continued use of redesigned air bags and require a return to overly

aggressive air bags; it did not represent an analysis of how easy it

would be to meet that particular test requirement in the context of the

overall set of proposed requirements.

In commenting on the NPRM, vehicle manufacturers indicated that, as

they consider various air bag designs, they face trade-offs in meeting

different proposed test requirements. For example, the optimum air bag

for meeting the unbelted rigid barrier test for the 50th percentile

adult male driver dummy would be a large air bag filling the space

between the dummy and the steering wheel. This would allow the

restraining forces to be imparted earlier in the crash event and exert

lower g forces on the occupant to allow optimal ride-down from the

crash. A smaller air bag would be optimum for meeting the unbelted

perpendicular rigid barrier test for 5th percentile adult female dummy

in the full forward seating position, since she is positioned closer to

the air bag and has less ride-down space to fill between the dummy and

the steering wheel. If an excessively large air bag is used, neck

readings for the 5th percentile adult female dummy will increase as the

larger air bag pushes the head back. Of course, the smallest possible

air bag would be optimum for meeting the proposed low risk deployment

tests intended to minimize risks from air bags to out-of-position

occupants. However, as air bags shrink,

[[Page 60580]]

so does their ability to provide protection, especially to larger

occupants in crashes with potential for serious or fatal injuries. We

note that while large air bags may be optimum for meeting the 30 mph

unbelted rigid barrier test with 50th percentile adult male dummies,

vehicle manufacturers have been able to meet the test with air bags of

varying sizes.

Recognizing the issues associated with the need to meet all of the

proposed tests together, we have tested current vehicles under a

variety of proposed test procedures. For four of the vehicles for which

we conducted a 48 km/h (30 mph) rigid barrier test using unbelted 50th

percentile adult male dummies, we also conducted a 48 km/h (30 mph)

rigid barrier test using unbelted 5th percentile adult female dummies.

For all these tests, it bears emphasizing that these vehicles were not

designed to comply with the final rule that will be issued in this

rulemaking. Thus, while it is useful to know whether current vehicles

already meet the tests, the test failures can tell us only which

vehicles need to be redesigned. They do not indicate that vehicles

cannot be redesigned in the time provided by TEA 21 to comply with that

final rule.

Three of the four unbelted 5th percentile adult female driver dummy

responses in these tests passed all the injury criteria performance

limits we are proposing in the SNPRM. (For the same make model

vehicles, the 50th percentile adult male driver dummy also passed all

the injury criteria performance limits.). In the fourth test, of the MY

1999 Dodge Intrepid, the 5th percentile adult female driver dummy

failed both the chest displacement and Nij performance limits; however

the 50th percentile adult male driver dummy passed all the relevant

injury criteria performance limits when tested in the same vehicle.

Two of the four unbelted 5th percentile adult female passenger

dummy responses passed all the injury criteria performance limits. The

MY 1999 Dodge Intrepid slightly exceeded the chest g performance limit

(with a value of 62.2 g) and the MY 1999 Toyota Tacoma significantly

failed to meet the Nij performance limit (with a value of 2.65).

Two of the four vehicles, the MY 1999 Saturn SL1 and the MY 1998

Ford Taurus, however, passed all the injury criteria performance limits

for the driver and passenger using both unbelted 5th percentile adult

female and unbelted 50th percentile adult male dummies in the rigid

barrier crash tests at 48 km/h (30 mph).

We have also recently conducted rigid barrier tests at 48 km/h (30

mph) using belted 50th percentile adult male and belted 5th percentile

adult female dummies in MY 1998 and 1999 vehicles. In 18 tests

conducted with the belted 50th percentile adult male dummies, the

vehicles passed all the proposed injury criteria performance limits for

both driver and passenger. In 17 tests conducted with belted 5th

percentile adult female dummies, the vehicles passed all the injury

criteria performance limits for the passenger dummy; however, the

driver dummy exceeded the proposed Nij injury criteria performance

limit in approximately 35% of the tests.

We also conducted static out-of-position tests using the 5th

percentile adult female driver dummy and 6-year-old child passenger

dummy on six MY 1999 vehicles. The vehicles that were selected were the

same as those used in the 48 km/h (30 mph) rigid barrier test with

unbelted 50th percentile adult male dummies. (Again, we note that the

vehicles were not designed with these test requirements in mind.) Four

out of six vehicles, including the MY 1999 Saturn SL1, passed all the

static out-of-position test requirements on the driver's side. The

remaining two vehicles failed the Nij criteria in Position 1, but

passed all the criteria in Position 2.

With the 6-year-old child dummies on the passenger side, only one

vehicle, the MY 1999 Acura RL with a dual stage inflator, met all the

proposed injury criteria performance limits in both Position 1 and

Position 2 tests. Only the primary stage was fired in the tests.

Looking at the various tests we have conducted, it appears that the

proposed test requirements are achievable by a number of vehicles even

though they were not designed to comply with those requirements. These

vehicles meet the 48 km/h (30 mph) unbelted barrier test with both

unbelted 50th percentile adult male dummies and unbelted 5th percentile

adult female dummies, and the driver side out-of-position test, with

single level inflators. The MY 1999 Saturn SL1 appears to be such a

vehicle.

Dual level inflators could make it easier to meet the tests. For

example, a higher inflation rate could be used for 50th percentile

adult males, while a lower inflation rate could be used for 5th

percentile adult female drivers with the seat full forward and for

child passengers.

We note that, for the passenger side, a weight sensor or other

suppression device might be needed to meet passenger side out-of-

position requirements for children, even if a dual level inflator is

used. Moreover, a weight sensor or other suppression device would

likely be needed to meet requirements for rear facing infant seats.

However, the use of a weight sensor or other suppression device on the

passenger side should not affect the ability of the vehicle to meet the

proposed unbelted and belted crash test requirements using 50th

percentile adult male dummies and 5th percentile adult female dummies,

since the addition of such a device does not affect the characteristics

of the air bag itself.

While the proposed requirements appear to be achievable, the number

of failures illustrate that many vehicles will need to be redesigned in

a short period of time to meet a highly complex set of new

requirements. In many cases, manufacturers will be introducing several

new technologies simultaneously: dual level inflators, seat belt

sensors, weight/pattern seat sensors, seat track position sensors, more

complex algorithms, etc.

In this context, we recognize that simultaneous implementation of

these various proposals for minimizing risk and enhancing protection

will necessitate considerable care and effort by the vehicle

manufacturers. In a normal rulemaking, we would have broad discretion

to adjust the implementation schedule to facilitate initial compliance.

In this rulemaking, our discretion to set the schedule for implementing

the amendments required by TEA 21 is limited by that Act. Our final

rule must provide that the phasing-in of those amendments begins not

later than September 1, 2003, and ends not later than September 1,

2006.

However, we believe that nothing in TEA 21 derogates our inherent

authority to make temporary adjustments in the requirements we adopt

if, in our judgment, such adjustments are necessary or prudent to

promote the smooth and effective achievement of the goals of the

amendments. For example, adjustments could be made to test speeds or

injury criteria. One possibility would be to issue a final rule

temporarily reducing the maximum speed for the unbelted rigid barrier

test to 40 km/h (25 mph) (or some other speed, e.g., 44 km/h (27.5

mph)) and then increasing it to 48 km/h (30 mph) after an appropriate

period of time, e.g., after the TEA 21 phase-in. Another possibility

would be to temporarily permit relaxed injury criteria performance

limits (e.g., 72 g chest acceleration limit instead of 60 g chest

acceleration limit) in unbelted rigid barrier tests between 25 mph and

30 mph.

[[Page 60581]]

This document seeks comment on still another possibility for the

final rule: permanently reducing the unbelted rigid barrier test speed

to 40 km/h (25 mph) and temporarily leaving the belted rigid barrier

test speed at 48 km/h (30 mph). Under the final rule, the latter test

speed would later, sometime after the TEA 21 phase-in schedule,

increase to 56 km/h (35 mph).\23\

---------------------------------------------------------------------------

\23\ We recognize that this alternative would increase the test

speed of the belted test to the level of the belted test currently

conducted under NHTSA's NCAP program. If this alternative were

chosen, NHTSA contemplates retaining the current NCAP test speed

through the end of the TEA 21 phase-in period. The agency would then

review that NCAP test.

---------------------------------------------------------------------------

We note that we have previously considered, in rulemaking, a 40 km/

h (25 mph) maximum speed for the unbelted rigid barrier test. However,

we considered this issue in the context of Standard No. 208's historic

requirements, i.e., testing only with 50th percentile adult male

dummies and the old injury criteria, which did not include neck

criteria.

Fifteen years ago, in our rulemaking establishing automatic

protection requirements, GM advocated a 40 km/h (25 mph) unbelted rigid

barrier test to facilitate passive interiors, i.e., building in safety

by improving such things as the steering columns and padding. At that

time, GM believed passive interiors would be better than automatic

restraints, i.e., air bags or automatic seat belts.

Based on available test data, we concluded that it was generally

evident that it was within the state-of-the art to pass Standard No.

208's head and chest injury criteria at 40 km/h (25 mph) with unbelted

50th percentile adult male dummies without air bags. We stated that we

had virtually no data on what diminution in safety would occur if the

lower standard were used and that there was no basis for making such a

change. See final rule published in the Federal Register (49 FR 28962,

28995; July 17, 1984).

We also note that, for the vehicles we recently tested at 48 km/h

(30 mph) for this rulemaking, we also tested a small subset at 40 km/h

(25 mph) with unbelted 50th percentile male driver and passenger

dummies. In the three tests, the vehicles passed all the proposed

driver and passenger injury criteria performance limits with one

exception involving a model year 1999 Toyota Tacoma. The passenger

dummy exceeded the proposed Nij limit in this test. We also conducted

two 40 km/h (25 mph) rigid barrier crash tests with unbelted 5th

percentile adult female driver and passenger dummies. Again, the

vehicles passed all the proposed driver and passenger injury criteria

performance limits with one exception involving the model year 1999

Toyota Tacoma. Again, the passenger dummy exceeded the proposed Nij

limit on the passenger side.

In light of the fact that vehicle manufacturers are now

recommending an unbelted rigid barrier crash test alternative that

omits the oblique tests, we also note that we addressed the possibility

of eliminating the unbelted oblique tests in the aftermath of that same

rulemaking. See NPRM published in the Federal Register (50 FR 14589,

14592-14594) on April 12, 1985, and final rule published in the Federal

Register (51 FR 9800, 9801-9802) on March 21, 1986.

We decided to retain the oblique tests in that rulemaking. We noted

that although oblique tests generally produce lower injury levels, they

do not consistently produce that result. We also expressed concern that

air bags that only need to meet a perpendicular impact could be made

much smaller. We stated that, in such a case, in an oblique crash, an

unbelted occupant could roll off the smaller bag and strike the A-

pillar or instrument panel.

We welcome comments on how we should consider our past decisions

and the rationales underlying them in this current rulemaking.

We note that while we are seeking comments on alternative unbelted

tests, including alternative speeds and injury criteria, we plan to

adopt a single unbelted test or set of unbelted tests for the final

rule. That is, we do not plan to provide a manufacturer option in this

area. Depending on the comments, we may adopt some combination of the

tests discussed above.

To help us reach a decision on what unbelted test requirements

should be included in Standard No. 208, we request commenters to

address the following questions:

1. How do the two proposed alternative unbelted crash tests compare

in representing the range of frontal crashes which have a potential to

cause serious injuries or fatalities? Please answer this separately for

the low and high end of the proposed range of upper speeds for each

alternative, i.e., 40 and 48 km/h (25 and 30 mph) for the unbelted

rigid barrier test and 48 and 56 km/h (30 mph and 35 mph) for the

unbelted offset deformable barrier test. In answering this question,

please consider the entire range of tests incorporated into each

alternative. Please specifically address representativeness with

respect to (a) crash pulses, (b) crash severities, and (c) occupant

positioning, and provide separate answers for crashes likely to cause

fatalities and crashes likely to cause serious but not fatal injuries.

2. How do the two alternatives compare with respect to

repeatability, reproducibility, objectivity, and practicability issues?

3. What effects would each of the alternative types of unbelted

tests and each of the alternative maximum test speeds discussed in this

SNPRM have on air bag design, performance, risks and benefits, and on

amount of depowering permitted? Answers should focus particularly on

unbelted 40 km/h (25 mph)/belted 56 km/h (35 mph) versus unbelted 48

km/h (30 mph)/belted 48 km/h (30 mph), and on unbelted 56 km/h (35

mph)offset/belted 48 km/h (30 mph) versus unbelted 48 km/h (30 mph)/

belted 48 km/h (30 mph). To what extent can it be concluded that a

countermeasure needed to meet each alternative would ensure protection

in frontal crashes not directly represented by the tests included in

that alternative, e.g., crashes with different pulses (harder or

softer) or different severities (more severe or less severe)? Please

quantify, to the extent possible, the amount of protection that would

be ensured in other types of crashes, i.e., what the injury criteria

measurements would be. Please address whether and how the answer to

this question would differ for the low and high end of the proposed

range of upper speeds for each alternative.

4. To what extent would current air bag systems (or air bag systems

being developed for near-term application) have difficulty

distinguishing between a high speed offset deformable barrier test and

a low speed crash during the time the decision whether to deploy the

air bag must be made? What technological solutions, e.g., advanced

sensing systems (including use of satellite sensors and improved

algorithms) are available to address this potential problem? How should

we consider this issue in selecting among the available unbelted crash

test alternatives?

5. One reason for adopting a test requirement that is less

stringent than another during the TEA 21 phase-in period would be to

provide an extra margin of flexibility and facilitate compliance during

the time vehicle manufacturers are introducing advanced air bags

incorporating multiple new technologies. An example of such an approach

would be the phase-in sequence described above in which the final rule

would provide that the maximum speed for the unbelted rigid barrier

test would initially be 40 km/h

[[Page 60582]]

(25 mph) (or some other speed) and then increase to 48 km/h (30 mph)

after an appropriate fixed period of time. If we were to adopt a less

stringent test requirement for an initial period, how long should that

period be and why?

6. What factors should we consider in selecting a maximum speed for

the two alternatives?

7. The severity of a crash test requirement could be adjusted

either by reducing the maximum speed at which the test is conducted or

by leaving the maximum speed unchanged, but relaxing the injury

criteria performance limits for the tests that are conducted near the

upper end of the range of test speeds. For example, if we were to

reduce temporarily the severity of the unbelted up-to-48 km/h (30 mph)

rigid barrier test, one possible way of doing this would be to reduce

the stringency of the injury criteria performance limits between 40 km/

h (25 mph) (or some other speed) and 48 km/h (30 mph). While this could

provide significant increased flexibility to vehicle manufacturers, it

could still address the issue of protection in higher speed crashes.

Also, certification and compliance test data could be directly compared

to that obtained in 48 km/h (30 mph) rigid barrier crash tests over

many years. We specifically request comments on this approach and what

injury criteria performance limits would be appropriate if we were to

adopt it.

8. Should we consider combining aspects from each of the two

unbelted alternatives? For example, the unbelted rigid barrier test

alternative includes both perpendicular and angle tests. A variation on

this approach might be to retain the perpendicular test, but replace

the angle tests with offset deformable barrier tests. We request

comments on this or any other possible ways of combining aspects from

the two unbelted alternatives.

9. Given the existing and anticipated advanced air bag

technologies, to what extent is it necessary, and why, to link

decisions about improving protection to decisions about minimizing the

risks? What portion of those risks would remain after full use of

existing and anticipated advanced air bag technologies?

10. If it is believed that a return to the 48 km/h (30 mph)

unbelted barrier test would necessitate an increase in the power of any

vehicle's air bags, indicate which models would need air bags with

increased power and indicate the potential amount of increase. Explain

how the amount of needed increase was determined and the effects on

safety of such an increase.

11. To what extent could non-air bag changes, such as improved

crush zones, be used to avoid any increases in air bag aggressivity if

there were a return to the 48 km/h (30 mph) unbelted barrier test? To

what extent can advanced features such as improved fold patterns,

lighter fabrics and recessed air bag modules be used to offset, or more

than offset, any increases in power so that those increases do not

result in increased air bag aggressivity?

12. To what extent could the various types of static suppression be

used to reduce the risk to children? In what circumstances would such

suppression not minimize risk? To what extent could the lower level of

dual-level inflators be linked with sensors of such factors as crash

severity, seat position, belt use and weight/pattern be used to reduce

the risk to drivers who adjust their seats full forward or nearly full

forward? In what circumstances would such technology not minimize risk?

If there would be residual risk to children or to those drivers after

the use of those technologies, what is the magnitude of that risk? To

what extent would that residual risk be affected by the decision

regarding an unbelted test requirement?

13. To what extent does each vehicle manufacturer plan to take full

advantage, across their vehicle fleets, of the advanced air bag and

other technologies mentioned in questions 11 and 12 above?

14. Given that available test data indicate that some vehicles

already meet or exceed the injury criteria for 50th percentile male

dummies in unbelted 48 km/h (30 mph) tests, explain why those margins

of compliance cannot be increased in the time provided by the TEA 21

schedule and why other vehicles cannot be designed to achieve similar

margins of compliance.

15. Provide test data and analysis to support the answers to

questions 1-14.

16. To what extent do available test data regarding advanced air

bag technologies support the appropriateness of or need for each of the

alternative types unbelted tests and each of the alternative maximum

test speeds discussed in this SNPRM? Answers should focus particularly

on unbelted 40 km/h (25 mph)/belted 56 km/h (35 mph) versus unbelted 48

km/h (30 mph)/belted 48 km/h (30 mph), and on unbelted 56 km/h (35

mph)offset/belted 48 km/h (30 mph) versus unbelted 48 km/h (30 mph)/

belted 48 km/h (30 mph).

17. What lead time would be needed for a 56 km/h (35 mph) belted

rigid barrier test requirement?

ii. Proposed Array of Crash Test Requirements.

As noted earlier, vehicle manufacturers argued that some of the

crash test requirements we proposed in the NPRM were redundant, given

the other tests. In developing this SNPRM, we have carefully considered

whether we could reduce the number of proposed tests without

significantly affecting the benefits of the NPRM. Using the methodology

for counting tests discussed earlier in this document, we are proposing

a total of nine crash tests instead of 14.

The specific nine tests differ, of course, depending on which

alternative unbelted tests are included.

The set of nine tests which includes the unbelted rigid barrier

test includes the following tests:

--belted rigid barrier test (perpendicular and up to 30

degrees) using 50th percentile adult male dummies (counts as three

tests: one at +30 degrees, one perpendicular, and one at -30 degrees);

--belted rigid barrier test (perpendicular only) using 5th percentile

adult female dummies;

--unbelted rigid barrier test using 50th percentile adult male dummies

(counts as three tests);

--unbelted rigid barrier test (perpendicular only) using 5th percentile

adult female dummies; and

--belted up-to-40 km/h (25 mph) offset deformable barrier test (driver

side of the vehicle engaged with the barrier) using 5th percentile

adult female dummies.

This set of proposed tests eliminates five tests that were included

in the NPRM. First, for both the belted and unbelted rigid barrier

tests, we are proposing to test the 5th percentile adult female dummy

in the perpendicular test only, i.e., not in oblique tests. This would

eliminate four tests.

In many cases, crash tests become less stringent as dummies become

lighter and/or closer to the air bag. However, this is not true if the

dummy is so close that it contacts the air bag early in the deployment

process. For the rigid barrier test using 5th percentile adult female

dummies, the condition in which this would most likely occur is in a

perpendicular impact. Therefore, we believe that the perpendicular

tests (belted and unbelted) would address this concern. We also believe

that, if the vehicle can pass the perpendicular test with 5th

percentile female dummies and the oblique tests with 50th percentile

adult male dummies, it will also pass

[[Page 60583]]

the oblique tests using 5th percentile adult female dummies.

The primary function of the oblique test is to assure a wide air

bag. The 50th percentile adult male dummy presents a greater challenge

than the 5th percentile adult female dummy does in such a test. Thus,

the oblique tests with the 5th percentile adult female dummy would add

test costs without providing additional safety benefits.

Second, for the belted up-to-40 km/h (25 mph) offset deformable

barrier test, we are proposing that the test be conducted only with the

driver side of the vehicle engaged with the barrier. This would

eliminate one additional test. We believe that testing the vehicle on

the driver side only would be a sufficient means of testing air bag

sensing systems.

We note, by contrast, that we believe it would be necessary to test

the vehicle with each side of the vehicle engaged if we adopted the

unbelted high speed offset deformable barrier test instead of the

unbelted rigid barrier test to ensure that the air bags are wide enough

to provide protection for occupants that move forward in a direction

that is either to the right or left of perpendicular.

The set of nine tests which includes the unbelted high speed offset

deformable barrier test includes the following tests:

--belted rigid barrier test (perpendicular and 30 degrees)

using 50th percentile adult male dummies (counts as three tests);

--belted rigid barrier test (perpendicular only) using 5th percentile

adult female dummies;

--unbelted offset deformable barrier test (driver and passenger sides

of vehicle engaging the barrier) using 50th percentile adult male

dummies (counts as two tests);

--unbelted offset deformable barrier test (driver and passenger sides

of vehicle engaging the barrier) using 5th percentile adult female

dummies (counts as two tests); and

--belted up-to-40 km/h (25 mph) offset deformable barrier test (driver

side of the vehicle engaged with the barrier) using 5th percentile

adult female dummies.

In the NPRM, we proposed specifications for the deformable barrier

to be used in offset deformable barrier tests. The specifications for

this barrier would be included in Part 587. We are not republishing the

specifications in this SNPRM but expect to proceed to a final rule in a

separate document. We do not expect any significant changes from the

NPRM.

We also proposed in the NPRM to include, for all crash tests

specified by the standard, certain vehicle integrity requirements. The

proposal specified that vehicle doors may not open during the crash

test and that, after the crash test, it must be possible for

technicians to open the doors and move the seats as necessary to allow

evacuation of all occupants.

Several commenters raised concerns about these proposed

requirements, including

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