[Federal Register: May 12, 2009 (Volume 74, Number 90)]
[Rules and Regulations]
[Page 22347-22393]
[DOCID:fr12my09-10]

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Part IV

Department of Transportation

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National Highway Traffic Safety Administration

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49 CFR Parts 571 and 585

Federal Motor Vehicle Safety Standards; Roof Crush Resistance; Phase-In
Reporting Requirements; Final Rule

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 571 and 585

[Docket No. NHTSA-2009-0093]
RIN 2127-AG51

Federal Motor Vehicle Safety Standards; Roof Crush Resistance;
Phase-In Reporting Requirements

AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation.

ACTION: Final rule.

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SUMMARY: As part of a comprehensive plan for reducing the risk of
rollover crashes and the risk of death and serious injury in those
crashes, this final rule upgrades the agency's safety standard on roof
crush resistance in several ways.
    First, for the vehicles currently subject to the standard, i.e.,
passenger cars and multipurpose passenger vehicles, trucks and buses
with a Gross Vehicle Weight Rating (GVWR) of 2,722 kilograms (6,000
pounds) or less, the rule doubles the amount of force the vehicle's
roof structure must withstand in the specified test, from 1.5 times the
vehicle's unloaded weight to 3.0 times the vehicle's unloaded weight.
Second, the rule extends the applicability of the standard so that it
will also apply to vehicles with a GVWR greater than 2,722 kilograms
(6,000 pounds), but not greater than 4,536 kilograms (10,000 pounds).
The rule establishes a force requirement of 1.5 times the vehicle's
unloaded weight for these newly included vehicles. Third, the rule
requires all of the above vehicles to meet the specified force
requirements in a two-sided test, instead of a single-sided test, i.e.,
the same vehicle must meet the force requirements when tested first on
one side and then on the other side of the vehicle. Fourth, the rule
establishes a new requirement for maintenance of headroom, i.e.,
survival space, during testing in addition to the existing limit on the
amount of roof crush. The rule also includes a number of special
provisions, including ones related to leadtime, to address the needs of
multi-stage manufacturers, alterers, and small volume manufacturers.

DATES: If you wish to petition for reconsideration of this rule, your
petition must be received by June 26, 2009.
    Effective date: The date on which this final rule amends the CFR is
July 13, 2009. The incorporation by reference of a publication listed
in the rule is approved by the Director of the Federal Register as of
July 13, 2009.
    Compliance dates:
    Passenger cars and multipurpose passenger vehicles, trucks and
buses with a GVWR of 2,722 kilograms (6,000 pounds) or less. This final
rule adopts a phase-in of the upgraded roof crush resistance
requirements for these vehicles. The phase-in begins on September 1,
2012. By September 1, 2015, all of these vehicles must meet the
upgraded requirements, with certain exceptions. Vehicles produced in
more than one stage and altered vehicles need not meet the upgraded
requirements until September 1, 2016.
    Multipurpose passenger vehicles, trucks and buses with a GVWR
greater than 2,722 kilograms (6,000 pounds) and less than or equal to
4,536 kilograms (10,000 pounds). All of these vehicles must meet the
requirements beginning September 1, 2016, with certain exceptions.
Vehicles produced in more than one stage and altered vehicles need not
meet the requirements until September 1, 2017.

ADDRESSES: If you wish to petition for reconsideration of this rule,
you should refer in your petition to the docket number of this document
and submit your petition to: Administrator, National Highway Traffic
Safety Administration, 1200 New Jersey Avenue, SE., West Building,
Washington, DC 20590.
    The petition will be placed in the docket. Anyone is able to search
the electronic form of all documents received into any of our dockets
by the name of the individual submitting the document (or signing the
document, if submitted on behalf of an association, business, labor
union, etc.). You may review DOT's complete Privacy Act Statement in
the Federal Register published on April 11, 2000 (Volume 65, Number 70;
Pages 19477-78) or you may visit http://www.dot.gov/privacy.html.

FOR FURTHER INFORMATION CONTACT: For non-legal issues, you may call
Christopher J. Wiacek, NHTSA Office of Crashworthiness Standards,
telephone<PHONE_NUMBER>. For legal issues, you may call J. Edward
Glancy, NHTSA Office of Chief Counsel, telephone<PHONE_NUMBER>. You may
send mail to these officials at the National Highway Traffic Safety
Administration, 1200 New Jersey Avenue, SE., West Building, Washington,
DC 20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary
    a. Final Rule
    b. How This Final Rule Differs From the NPRM and/or SNPRM
II. Overall Rollover Problem and the Agency's Comprehensive Response
    a. Prevention
    b. Occupant Containment
    c. Occupant Protection
III. The Role of Roof Intrusion in the Rollover Problem
IV. The Agency's Proposed Rule
    a. NPRM
    b. SNPRM
    c. Congressional Mandate
V. Overview of Comments
VI. Agency Decision and Response to Comments
    a. Primary Decisions
    1. Basic Nature of the Test Requirements--Quasi-Static vs.
Dynamic Tests
    2. Vehicle Application
    3. Single-Sided or Two-Sided Tests
    4. Upgraded Force Requirement--Specified Strength to Weight
Ratio (SWR)
    5. Performance Criteria--Headroom, Platen Travel, or Both
    6. Leadtime and Phase-In
    b. Aspects of the Test Procedure
    1. Tie-Down Procedure
    2. Platen Angle and Size
    3. Testing Without Windshields and/or Other Glazing in Place
    4. Deletion of Secondary Plate Positioning Procedure
    5. Removal of Roof Components
    6. Tolerances
    c. Requirements for Multi-Stage and Altered Vehicles
    d. Other Issues
    1. Convertibles and Open Bodied Vehicles
    2. Vehicles Without B-Pillars
    3. Heavier Vehicles With a High Height to Width Aspect Ratio
    4. Active Roofs
    5. Whether an Additional SNPRM Is Needed
    6. Rear Seat Occupants
    7. New Car Assessment Program (NCAP)
    8. Possible Energy Requirement
    9. Advanced Restraints
VII. Costs and Benefits
VIII. Rulemaking Analyses and Notices
Appendix A--Analysis of Comments Concerning Dynamic Testing
Appendix B--Two-Sided Test Results
Appendix C--Single-Sided Test Results

I. Executive Summary

a. Final Rule

    As part of a comprehensive plan for reducing the serious risk of
rollover crashes and the risk of death and serious injury in those
crashes, this final rule upgrades Federal Motor Vehicle Safety Standard
(FMVSS) No. 216, Roof Crush Resistance.
    For the vehicles currently subject to the standard, passenger cars
and multipurpose passenger vehicles, trucks and buses with a GVWR of
2,722 kilograms (6,000 pounds) or less, the rule doubles the amount of
force the vehicle's roof structure must withstand in the specified
test, from 1.5 times the

vehicle's unloaded weight to 3.0 times the vehicle's unloaded weight.
The rule also extends the applicability of the standard so that it will
also apply to vehicles with a GVWR greater than 2,722 kilograms (6,000
pounds), but not greater than 4,536 kilograms (10,000 pounds),
establishing a force requirement of 1.5 times the vehicle's unloaded
weight for these heavier vehicles.
    Under today's rule, all of the above vehicles must meet the
specified force requirements in a two-sided test instead of a single-
sided test, i.e., the same vehicle must meet the force requirements
when tested first on one side and then on the other side of the
vehicle. The rule also establishes a new requirement for maintenance of
headroom, i.e., survival space, during testing, in addition to the
existing limit on the amount of roof crush. The rule also includes
special provisions to address the needs of multi-stage manufacturers,
alterers, and small volume manufacturers.
    NHTSA developed its proposal to upgrade roof crush resistance
requirements after considerable analysis and research, including
considering comments received in response to a Request for Comments
(RFC) notice published in 2001. Prior to publishing the RFC, the agency
conducted a research program to examine potential methods for improving
the roof crush resistance requirements. The agency testing program
included full vehicle dynamic rollover testing, inverted vehicle drop
testing, and comparing inverted vehicle drop testing to a modified
FMVSS No. 216 test. After considering the results of the testing and
other available information, the agency concluded that the quasi-static
procedure provides a suitable representation of the real-world dynamic
loading conditions, and the most appropriate one on which to focus our
upgrade efforts.
    Today's rule reflects careful consideration of comments we received
in response to the notice of proposed rulemaking (NPRM) published in
2005 and a supplemental notice of proposed rulemaking (SNPRM) published
in January 2008. NHTSA published the SNPRM to obtain public comment on
a number of issues that might affect the content of the final rule,
including possible variations in the proposed requirements. In the
SNPRM, the agency also announced the release of the results of various
vehicle tests conducted since the NPRM.
    While this rulemaking action to improve roof strength is part of
our comprehensive plan for addressing the serious problem of rollover
crashes, this action, by itself, addresses a relatively small subset of
that problem. There are more than 10,000 fatalities in rollover crashes
each year. To address that problem, our comprehensive plan includes
actions to (1) reduce the occurrence of rollovers, (2) mitigate
ejection, and (3) enhance occupant protection when rollovers occur
(improved roof crush resistance is included in this third category).
    Our analysis shows that of the more than 10,000 fatalities that
occur in rollover crashes each year, roof strength is relevant to only
about seven percent (about 667) of those fatalities. We estimate that
today's rule will prevent 135 of those 667 fatalities.
    The portions of our comprehensive plan that will have the highest
life-saving benefits are the ones to reduce the occurrence of rollovers
(prevention) and to mitigate ejection (occupant containment). We
estimate that by preventing rollovers, electronic stability control
(ESC) will reduce the more than 10,000 fatalities that occur in
rollover crashes each year by 4,200 to 5,500 fatalities (and also
provide significant additional life-saving benefits by preventing other
types of crashes). In the area of mitigating ejection, significant
life-benefits are and/or will occur by our continuing efforts to
increase seat belt use and our upcoming rulemaking on ejection
mitigation. A more complete discussion of our comprehensive plan is
discussed later in this document.

b. How This Final Rule Differs From the NPRM and/or SNPRM

    The more noteworthy changes from the NPRM are outlined below and
explained in detail later in this preamble. More minor changes are
discussed in the appropriate sections of this preamble.
    Higher force requirement (strength-to-weight ratio (SWR level)).
While we proposed an SWR level of 2.5 in the NPRM for the vehicles that
have been subject to the standard, we noted in the SNPRM that the
agency could adopt a higher or lower value for this final rule. We are
adopting an SWR of 3.0 for them in this final rule. An SWR of 1.5 will
apply to the heavier light vehicles that have previously not been
subject to the standard.
    Two-sided test. While we proposed a single-sided test in the NPRM,
we conducted additional testing and addressed the possibility of a two-
sided test in the SNPRM. Today's rule adopts a two-sided test
requirement for all vehicles subject to the standard.
    Maintaining intrusion limit in addition to new headroom
requirement. In the NPRM, we proposed to replace the current limit on
intrusion (platen travel requirement) with a new headroom requirement.
For this final rule, we are maintaining the intrusion limit as well as
adopting the proposed headroom requirement.
    Use of headform positioning fixture instead of a test dummy. In the
NPRM, we proposed to use test dummies as part of the test procedure for
measuring headroom. For this final rule, we are using headform
positioning fixtures for this purpose.
    Phase-in. We did not include a phase-in in the NPRM. For this final
rule, we are phasing in the upgraded roof strength requirements for the
lighter vehicles previously subject to FMVSS No. 216, and providing
longer leadtime (without a phase-in) for the heavier light vehicles.
    Limited exclusion for certain multi-stage trucks. Due to concerns
about practicability, we are excluding from FMVSS No. 216 a very
limited group of multistage trucks with a GVWR greater than 2,722
kilograms (6,000 pounds), ones not built on either a chassis cab or an
incomplete vehicle with a full exterior van body.
    Updated benefits and costs. We have updated our analysis of
benefits and costs. Our analysis appears in summary form in this
document, and in its entirety in the agency's Final Regulatory Impact
Analysis (FRIA).
    We estimate that the changes in FMVSS No. 216 will prevent 135
fatalities and 1,065 nonfatal injuries annually. The agency estimates
that compliance with the upgraded roof strength standard will increase
lifetime consumer costs by $69-114 per affected vehicle. Redesign costs
are expected to increase affected vehicle prices by an average of about
$54. Added weight is estimated to increase the lifetime cost of fuel
usage by $15 to $62 for an average affected vehicle. Total consumer
costs are expected to range from $875 million to $1.4 billion annually.
    Implied Preemption. We have reconsidered the tentative position
presented in the NPRM. We do not foresee any potential State tort
requirements that might conflict with today's final rule. Without any
conflict, there could not be any implied preemption.

II. Overall Rollover Problem and the Agency's Comprehensive Response

    Addressing vehicle rollovers is one of NHTSA's highest safety
priorities. According to 2007 FARS crash data, 10,196 people were
killed as occupants

in light vehicle rollover crashes, which represents 35 percent of all
occupants killed that year in crashes. FARS reported that approximately
57 percent were partially or completely ejected from the vehicle
(including approximately 47 percent who were completely ejected).
    Rollover crashes are complex and chaotic events. Rollovers can
range from a single quarter turn to eight or more quarter turns, with
the duration of the rollover crash lasting from one to several seconds.
The wide range of rollover conditions occurs because these crashes
largely occur off road where the vehicle motion is highly influenced by
roadside conditions. Also, rollover crashes tend to occur at higher
speeds than other crash types due to the energy required to initiate
the rollover motion.
    NHTSA has been pursuing a comprehensive and systematic approach
towards reducing the fatalities and serious injuries that result from
rollover crashes. As part of our safety standard rulemaking, this
approach establishes various repeatable test procedures and performance
requirements that will generate countermeasures effective in the
chaotic real-world events. Due to the complex nature of a rollover
event and the particularized effect of each element of the
comprehensive approach taken by the agency to address these crashes,
each element addresses a specific segment of the total rollover
problem. Accordingly, each initiative has a different target population
and interacts with each of the other rollover strategies. NHTSA has
initiatives in place to:
    1. Reduce the occurrence of rollover crashes (e.g., the requirement
for ESC on all light vehicles and the NCAP rollover ratings),
    2. Keep occupants inside the vehicle when rollovers occur (e.g.,
NHTSA's unyielding commitment to get passengers to buckle their seat
belts every time they ride in a vehicle, as well as the requirement for
enhanced door latches and the forthcoming rulemaking for ejection
mitigation), and
    3. Better protect the occupants kept inside the vehicle during the
rollover (e.g., the requirement for upper interior head protection and
this rulemaking for enhanced roof crush resistance).
    Each of these three initiatives must work together to address the
various aspects of the rollover problem.

a. Prevention

    The most effective way to reduce deaths and injuries in rollover
crashes is to prevent the rollover crash from occurring. On April 6,
2007, NHTSA published a final rule establishing FMVSS No. 126,
``Electronic stability control systems,'' to require ESC on passenger
cars, multipurpose passenger vehicles, trucks, and buses with a GVWR of
4,536 kilograms (10,000 pounds) or less. ESC systems use automatic
computer-controlled braking of individual wheels to assist the driver
in maintaining control in critical driving situations in which the
vehicle is beginning to lose directional stability at the rear wheels
or directional control at the front wheels. ESC systems effectively
monitor driver steering input and limit vehicle oversteer and
understeer, as appropriate. To comply with the new ESC standard,
vehicles will need individually adjustable braking at all four wheels,
and computer electronics to utilize this capability, a means for engine
torque adjustability and various onboard sensors (to measure yaw rate,
lateral acceleration, steering wheel angle and speed). The agency
estimates that ESC will save 5,300 to 9,600 lives in all types of
crashes annually once all light vehicles on the road are equipped with
ESC. The agency further anticipates that ESC systems will substantially
reduce (by 4,200 to 5,500 deaths) the more than 10,000 deaths each year
resulting from rollover crashes.

b. Occupant Containment

    Studies have shown that the fatality rate for an ejected vehicle
occupant is three times as great as that for an occupant who remains
inside of the vehicle. Thus, mitigating ejections offers potential for
significant safety gains. Safety belts are the most effective
crashworthiness countermeasure in reducing ejected rollover fatalities.
Studies have found that safety belts reduce fatalities in rollovers by
74 percent in passenger cars and 80 percent for light trucks.\1\ NHTSA
requires all vehicles manufactured after 1968 to have safety belts as
standard equipment.
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    \1\ Kahane, C. J., Fatality Reduction by Safety Belts for Front-
Seat Occupants of Cars and Light Trucks: Updated and Expanded
Estimates Based on 1986-99 FARS Data (NHTSA Report No. DOT HS 809
199).
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    However, of the 6,164 ejected occupant fatalities in light vehicle
rollover crashes, as reported by 2006 FARS, 1,135 were classified as
partial ejections. Fatal injuries from partial ejection can occur even
to belted occupants, e.g., when their head protrudes outside the window
and strikes the ground in a rollover. Therefore, as mandated by
SAFETEA-LU, NHTSA is working to establish performance standards to
reduce partial and complete ejection from outboard seating position
windows.
    Doors represent another common ejection route. As part of the
agency's comprehensive approach to rollover, and to harmonize with the
first Global Technical Regulation, NHTSA upgraded FMVSS No. 206, ``Door
locks and door retention components,'' in a final rule published on
February 6, 2007. This final rule added test requirements for sliding
doors, upgraded the door retention requirements, added secondary latch
requirements for doors other than hinged side doors and back doors, and
provided a new test procedure for assessing inertial forces. To comply
with the new requirements, it is anticipated that passenger vehicles
with sliding doors designed with one latch and pin locking mechanism
will need to be redesigned with two latches. The technology needed to
meet the upgraded standard would benefit vehicles in rollover crashes
where door openings were identified as a problem.

c. Occupant Protection

    Finally, when a rollover crash does occur and the occupants have
been contained within the vehicle compartment, it is important for the
roof structure to remain intact and maintain survival space. That is
the safety need addressed by today's final rule.

III. The Role of Roof Intrusion in the Rollover Problem

    Due to the high effectiveness of ESC in preventing an increasing
number of rollover crashes, and seat belts at preventing ejection, the
remaining target population relevant to roof crush occupant protection
is a relatively small subset of the occupants injured in rollovers. For
fatalities, the estimated total for the target population \2\ is about
seven percent (about 667) of all non-convertible light vehicle rollover
fatalities. Although the target population and potential for lives
saved are substantially smaller than can be attained by the first two
strategies of our comprehensive rollover plan, it is nevertheless a
very important aspect of the plan.
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    \2\ The target population estimates were based upon the results
from the 1997-2006 National Automotive Sampling System-
Crashworthiness Data System (NASS-CDS).
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    Looking at the target population relevant to roof crush occupant
protection more specifically, Table 1 below shows a breakdown of the
target population that could potentially benefit from roof crush
improvements. The target population for all light vehicles is
stratified by injury severity. The injury mechanism due to roof crush
for belted occupants is that the roof crushes during the roll event,
intrudes

into the occupant compartment, and causes head, face, or neck injury.
The table demonstrates how the final target population is derived from
the broad category of rollovers by eliminating cases in which roof
strength improvements would not be effective in reducing serious and
fatal injuries. For example, a stronger roof would not be expected to
provide benefits in cases where the roof was not involved; where the
occupant was totally ejected from the vehicle,\3\ or where the most
serious injury was not to the head, neck, or face due to the intruding
roof.
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    \3\ Strashny, ``The Role of Vertical Roof Intrusion in
Predicting Occupant Ejection,'' 2009. Strashny found that there was
no statistically significant relationship between the level of roof
intrusion and the probability of complete ejection. For this reason
completely ejection occupants were excluded from the target
population. However, partial ejections that meet the established
criteria are included.
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    The final target populations are shown in bold at the bottom of the
table. A full discussion of the basis for the target population is
included in the FRIA.

                  Table 1--Target Population Potentially Affected by Improved Roof Strength \4\
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                                                       AIS 1           AIS 2          AIS 3-5       Fatalities
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                                               All Light Vehicles
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All Vehicles:
    Non-Convertible Light Vehicles in Rollovers.         199,822          37,305          21,673          10,150
    Roof-Involved Rollover......................         164,213          32,959          19,262           8,645
    Some Fixed Object Collision on Top..........         153,520          29,419          17,766           7,559
    Not Totally Ejected.........................         149,850          26,033          12,355           3,654
    Using Safety Restraints.....................         116,670          14,327           8,970           2,096
    Outboard Seats..............................         115,018          14,241           8,781           2,096
    Roof Component Intrusion....................          68,730          10,922           6,842           1,444
                                                 ===============================================================
    Head, Neck, or Face Injury From Intruding             24,035           6,580           2,993             957
     Roof Component.............................
    Injury--Not MAIS \5\........................               0          -1,900          -1,252            -237
    Injury at MAIS--Not Sole Injury.............         -17,818            -292            -253             -53
                                                 ---------------------------------------------------------------
        Sole MAIS Injury........................           6,216           4,388           1,487             667
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                      Light Vehicles With a GVWR of 2,722 Kilograms (6,000 Pounds) or Less
----------------------------------------------------------------------------------------------------------------
PC & LT < 6,000 lbs:
    Non-Convertible Light Vehicles in Rollovers.         172,846          33,170          18,929           8,719
    Roof-Involved Rollover......................         144,410          29,098          17,360           7,536
    Some Fixed Object Collision on Top..........         136,080          26,270          16,122           6,484
    Not Totally Ejected.........................         133,241          23,400          11,406           3,142
    Using Safety Restraints.....................         104,571          12,421           8,379           1,936
    Outboard Seats..............................         103,249          12,373           8,190           1,936
    Roof Component Intrusion....................          60,061           9,370           6,372           1,304
                                                 ===============================================================
    Head, Neck, or Face Injury From Intruding             20,687           5,868           2,615             842
     Roof Component.............................
    Injury--Not MAIS............................               0          -1,771          -1,119            -157
Injury at MAIS--Not Sole Injury.................         -16,082            -262            -212             -50
                                                 ---------------------------------------------------------------
        Sole MAIS Injury........................           4,605           3,835           1,283             635
----------------------------------------------------------------------------------------------------------------
                         Light Vehicles With a GVWR above 2,722 Kilograms (6,000 Pounds)
----------------------------------------------------------------------------------------------------------------
LT > 6,000 lbs:
    Non-Convertible Light Vehicles in Rollovers.          26,975           4,135           2,744           1,431
    Roof-Involved Rollover......................          19,803           3,861           1,902           1,110
    Some Fixed Object Collision on Top..........          17,440           3,149           1,644           1,075
    Not Totally Ejected.........................          16,608           2,634             949             511
    Using Safety Restraints.....................          12,099           1,906             591             160
    Outboard Seats..............................          11,770           1,868             591             160
    Roof Component Intrusion....................           8,669           1,552             471             140
                                                 ===============================================================
    Head, Neck, or Face Injury From Intruding              3,348             712             378             116
     Roof Component.............................
    Injury--Not MAIS............................               0            -128            -133             -80
    Injury at MAIS--Not Sole Injury.............          -1,736             -31             -40              -3
                                                 ---------------------------------------------------------------
        Sole MAIS Injury........................           1,611             553             205              33
----------------------------------------------------------------------------------------------------------------

    The most significant exclusions resulted from requirements that
fatalities occurred in rollovers in which (1) the roof was damaged in a
rollover, (2) the damage was not caused by collision with a fixed
object, (3) the fatally injured occupants were not ejected, and (4)
those occupants were belted.
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    \4\ Note: The relevant target population used for the estimation
of benefits is identified in the row titled ``Sole MAIS Injury.''
Also, the numbers reflect rounding errors.
    \5\ Injury--Not MAIS: This means that the most serious injury
was to a portion of the body other than the head, neck or face.
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    It is important to understand what Table 1 indicates about the
safety

potential of addressing roof crush. Even if there were some way to
prevent every single rollover death resulting from roof crush, the
total lives saved would be 667, not the approximately 10,000 deaths
that result from rollover each year. This is why each initiative in
NHTSA's comprehensive program to address the different aspects of the
rollover problem is so important.
    The details of today's rule upgrading roof crush occupant
protection, including costs and benefits and the agency's analysis of
the public comments on our NPRM and SNPRM, are discussed in the rest of
this document.

IV. The Agency's Proposed Rule

a. NPRM

    On August 23, 2005, NHTSA published in the Federal Register (70 FR
49223) a NPRM to upgrade FMVSS No. 216, Roof Crush Resistance.\6\ FMVSS
No. 216 seeks to reduce deaths and serious injuries resulting from the
roof being crushed and pushed into the occupant compartment when the
roof strikes the ground during rollover crashes.
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    \6\ Docket No. NHTSA-2005-22143.
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    Current requirements.
    FMVSS No. 216 currently applies to passenger cars, and to
multipurpose passenger vehicles, trucks and buses with a GVWR of 2,722
kilograms (6,000 pounds) or less.
    The standard requires that when a large steel test plate (sometimes
referred to as a platen) is placed in contact with the roof of a
vehicle and then pressed downward, simulating contact of the roof with
the ground during a rollover crash, with steadily increasing force
until a force equivalent to 1.5 times the unloaded weight of the
vehicle is reached, the distance that the test plate has moved from the
point of contact must not exceed 127 mm (5 inches). The criterion of
the test plate not being permitted to move more than a specified amount
is sometimes referred to as the ``platen travel'' criterion. Under S5
of the standard, the application of force is limited to 22,240 Newtons
(5,000 pounds) for passenger cars, even if the unloaded weight of the
car times 1.5 is greater than that amount.
    Proposed upgrade.
    As discussed in the August 2005 NPRM, we developed our proposal to
upgrade roof crush resistance requirements after considerable analysis
and research, including considering comments received in response to a
RFC published in the Federal Register (66 FR 53376) \7\ on October 22,
2001. Prior to publishing the RFC, the agency conducted a research
program to examine potential methods for improving the roof crush
resistance requirements. The agency testing program included full
vehicle dynamic rollover testing, inverted vehicle drop testing, and
comparing inverted drop testing to a modified FMVSS No. 216 test. After
considering the results of the testing and other available information,
the agency concluded that the quasi-static procedure provides a
suitable representation of the real-world dynamic loading conditions,
and the most appropriate one on which to focus our upgrade efforts.
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    \7\ Docket No. NHTSA-1999-5572.
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    In our August 2005 NPRM, to better address fatalities and injuries
occurring in roof-involved rollover crashes, we proposed to extend the
application of the standard to vehicles with a GVWR of up to 4,536
kilograms (10,000 pounds), and to strengthen the requirements of FMVSS
No. 216 by mandating that the vehicle roof structures withstand a force
equivalent to 2.5 times the unloaded vehicle weight, and to eliminate
the 22,240 Newton (5,000 pound) force limit for passenger cars.
    Further, in recognition of the fact that the pre-test distance
between the interior surface of the roof and a given occupant's head
varies from vehicle model to vehicle model, we proposed to regulate
roof strength by requiring that the crush not exceed the available
headroom. Under the proposal, this requirement would replace the
current limit on test plate movement.
    The proposed new limit would prohibit any roof component from
contacting the head of a seated 50th percentile male dummy when the
roof is subjected to a force equivalent to 2.5 times the unloaded
vehicle weight. We note that this value is sometimes referred to as the
strength-to-weight ratio (SWR), e.g., a SWR of 1.5, 2.5, and so forth.
    We also proposed to:
     Allow vehicles manufactured in two or more stages, other
than chassis-cabs, to be certified to the roof crush requirements of
FMVSS No. 220, School bus rollover protection, instead of FMVSS No.
216.
     Clarify the definition and scope of exclusion for
convertibles.
     Revise the vehicle tie-down procedure to minimize
variability in testing.
    To accompany our proposal, we prepared a Preliminary Regulatory
Impact Analysis (PRIA) describing the costs and benefits. We estimated
that, if adopted, the proposal would result in 13-44 fewer fatalities
and 498-793 fewer non-fatal injuries each year. The total estimated
recurring fleet cost was $88 to $95 million. We estimated that
approximately 32 percent of the current vehicle fleet would need
improvements to meet the proposed upgraded requirements.

b. SNPRM

    On January 30, 2008, NHTSA published in the Federal Register (73 FR
5484) an SNPRM for our ongoing roof crush resistance rulemaking.\8\ In
that document, we asked for public comment on a number of issues that
might affect the content of the final rule, including possible
variations in the proposed requirements. We also announced the release
of the results of various vehicle tests conducted since the proposal.
---------------------------------------------------------------------------

    \8\ Docket No. NHTSA-2008-0015.
---------------------------------------------------------------------------

    In the SNPRM, we noted that we had been carefully analyzing the
numerous comments we had received on the NPRM, as well as the various
additional vehicle tests, including both single-sided tests and two-
sided tests, conducted since the NPRM. We invited comments on how the
agency should factor the new information into its decision. We noted
that while the NPRM focused on a specified force equivalent to 2.5
times the unloaded vehicle weight, the agency could adopt a higher or
lower value for the final rule. We explained, with respect to two-sided
testing, that we believed there was now sufficient available
information for the agency to consider a two-sided requirement as an
alternative to the single-sided procedure described in the NPRM. We
stated that we planned to evaluate both the single-sided and two-sided
testing alternatives for the final rule and requested comments that
would help us reach a decision on that issue.
    We also noted in the SNPRM that the agency had conducted additional
analysis concerning the role of vertical roof intrusion and post-crash
headroom in predicting roof contact injuries to the head, neck or face
during FMVSS No. 216 rollovers. At the time of the NPRM, the agency
estimated benefits based on post-crash headroom, the only basis for
which a statistical relationship with injury reduction had been
established. After the NPRM, with additional years of data available, a
statistically significant relationship between intrusion and injury for
belted occupants was established.

c. Congressional Mandate

    Section 10301 of SAFETEA-LU generally required the Secretary to
issue

a final rule upgrading roof crush resistance by July 1, 2008, while
providing for a later date under certain circumstances. That section
provides:

Sec. 10301. VEHICLE ROLLOVER PREVENTION AND CRASH MITIGATION.

    (a) In General.--Subchapter II of chapter 301 is amended by
adding at the end the following:

Sec.  30128. Vehicle rollover prevention and crash mitigation

    (a) IN GENERAL.--The Secretary shall initiate rulemaking
proceedings, for the purpose of establishing rules or standards that
will reduce vehicle rollover crashes and mitigate deaths and
injuries associated with such crashes for motor vehicles with a
gross vehicle weight rating of not more than 10,000 pounds.
* * * * *
    (d) Protection of Occupants.--One of the rulemaking proceedings
initiated under subsection (a) shall be to establish performance
criteria to upgrade Federal Motor Vehicle Safety Standard No. 216
relating to roof strength for driver and passenger sides. The
Secretary may consider industry and independent dynamic tests that
realistically duplicate the actual forces transmitted during a
rollover crash. The Secretary shall issue a proposed rule by
December 31, 2005, and a final rule by July 1, 2008.

    The statute provides that if the Secretary determines that the July
1, 2008 deadline for the final rule cannot be met, the Secretary is to
notify Congress and explain why that deadline cannot be met, and
establish a new date. The Secretary provided such notifications to
Congress, and established a date of April 30, 2009.

V. Overview of Comments

    NHTSA received comments from a wide variety of interested parties,
including vehicle manufacturers and their trade associations, suppliers
of automobile equipment and a supplier trade association, consumer
advocacy and other organizations, trial lawyers, engineering firms and
consultants, members of academia, elected officials and government
organizations, and private individuals. All of the comments may be
found in the docket for the NPRM or SNPRM. In this section, we provide
a broad overview of the significant comments. Where we identify
specific commenters, we cite representative comments.

General Approach and SWR

    Vehicle manufacturers were generally supportive of the agency's
proposal, while recommending a number of specific modifications. They
generally supported a SWR of 2.5, with caveats about sufficient
leadtime and test procedure issues. They expressed concerns about SWRs
higher than 2.5, including potential adverse effects on safety
resulting from increased mass.
    Consumer advocacy organizations and a number of other commenters
argued that it is not enough to upgrade the current quasi-static
requirement, and that a dynamic test requirement is needed. While
specific recommendations varied, one was for the agency to adopt an
upgraded quasi-static requirement now, and to proceed with further
rulemaking for a dynamic test.
    Advocates for Highway Safety (Advocates) stated that the proposed
quasi-static test cannot demonstrate actual roof crush resistance in
rollover crashes and that a dynamic test would address occupant
kinematics and injury responses in actual rollover crashes. Public
Citizen stated that a dynamic test could simultaneously evaluate the
performance of seat belts, doors, ejection and the roof. A number of
commenters supported specific dynamic tests.
    The Center for Auto Safety (CAS) stated that while it strongly
supports a dynamic test, it believes rollover protection can be
dramatically improved with a well-crafted quasi-static test. It argued
that test procedure changes related to roll angle and pitch angle are
needed to ensure that the roof receives appropriate shear stress.
    As to the SWR for an upgraded quasi-static test requirement,
consumer advocacy organizations and a number of other commenters argued
that the SWR should be significantly higher than 2.5. Many of these
commenters recommended a SWR of 3.5, with some recommending higher
levels.
    The Insurance Institute for Highway Safety (IIHS) submitted a new
study which it said supports increasing the SWR beyond 2.5. It stated
that based on the current evidence, it supports a SWR of 3.0 to 3.5.

Performance Criterion

    The agency received a variety of comments on the proposed headroom
reduction criterion. Some commenters, including consumer groups,
supported a headroom reduction criterion but argued that a platen
travel criterion is also needed. Several commenters expressed concern
that, for some vehicles, the proposed headroom reduction criterion
would be less stringent and less protective than the current platen
travel criterion. The agency also received comments recommending that
the agency make these criteria more stringent to protect taller
occupants, e.g., by using a 95th percentile adult male dummy instead of
a 50th percentile adult male dummy to measure headroom and by reducing
the amount of platen travel that is permitted.
    Vehicle manufacturers urged the agency to retain the current platen
travel criterion instead of adopting a headroom reduction criterion.
They argued, among other things, that using the headroom reduction
criterion would add unnecessary complexity to the test procedure and
result in problems related to repeatability and practicability. Some
manufacturers stated that if the agency adopts a headroom reduction
criterion, it should adopt a test procedure using a head positioning
fixture instead of a test dummy.
    IIHS stated that relating the allowable amount of roof crush in the
quasi-static test to the headroom in specific vehicles is a good
concept but that, in practice, the agency's research tests have not
shown that replacing the 5-inch platen travel criterion with the
headroom requirement would be a meaningful change to the standard and
may not justify the added complications to the test procedure.

Single- or Two-Sided Testing

    Several consumer advocacy organizations and other commenters
strongly supported two-sided testing. Public Citizen stated that in a
vast majority of rollover cases, the injured party was typically seated
on the far side, that is, the side of the second impact. It argued that
it is not possible to upgrade FMVSS No. 216 without a two-sided test
requirement.
    IIHS stated that while it supports any changes that would increase
the level of roof strength of the vehicle fleet, it has no real-world
data to address the potential benefits of two-sided testing. It stated
that a single-sided test with a higher SWR may be more effective at
promoting robust roof designs than a two-sided test with a lower SWR
requirement.
    The comments of vehicle manufacturers were somewhat mixed on the
issue of single- or two-sided testing. The Alliance of Automobile
Manufacturers (Alliance) stated that it believes the agency has
provided insufficient justification for two-sided testing. It stated
that the agency has not provided analysis demonstrating that two-sided
testing relates to real-world safety. The Alliance also expressed
concern that two-sided testing would amplify variability and
repeatability problems.
    The Association of International Automobile Manufacturers (AIAM)
stated that based on the information and

analysis provided by the agency regarding the two-sided test, it
believes that the test shows enough potential to merit further
consideration by the agency. AIAM argued that additional analysis would
be needed before it could provide a preferred regulatory approach, but
indicated that the two-sided approach would more directly address the
multiple roof contact weakening phenomenon.

Leadtime

    Vehicle manufacturers argued that a phase-in is needed for the
upgraded roof crush requirements. The Alliance stated that if the final
rule reflected a reasonable accommodation of the issues raised in its
comments, it would be reasonable for a phase-in to begin, with a
compliance percentage of 20 percent, on the first September 1, that
occurred more than 36 months after issuance of the final rule. That
organization stated that it would not be practicable to apply the
upgraded requirements to all new vehicles at once, since far more
vehicle models require redesigns than anticipated by NHTSA. The
Alliance requested a phase-in that incorporates carryforward credits.
It stated that additional leadtime would be necessary if the agency
adopted a head contact criterion instead of platen travel, a two-sided
test or a SWR higher than 2.5.

Costs and Benefits

    Many commenters addressed the PRIA, which analyzed the costs and
benefits and other impacts of the proposed rule, and a later discussion
of these impacts included in the SNPRM. Among other things, commenters
addressed the target population, the pass/fail rate of the current
fleet, cost and weight impacts, and estimates of benefits.

Preemption

    We received numerous comments on our discussion in the NPRM of the
possible preemptive effect of an upgraded roof crush standard on State
common law tort claims. Vehicle manufacturers and one organization
strongly supported the view that an upgraded roof crush standard would
conflict with and therefore impliedly preempt State rules of tort law
imposing more stringent requirements than the one ultimately adopted by
NHTSA. Consumer advocacy groups, members of Congress and State
officials, trial lawyers, consultants, members of academia, and private
individuals strongly opposed that view. The opposing comments from
State officials included one signed by 27 State Attorneys General and
the National Conference of State Legislatures.

Other Issues

    We received comments on many other issues. Commenters addressed a
number of issues concerning the FMVSS No. 216 test procedure, including
the vehicle tie-down procedure, platen angle and size, and whether the
vehicle should be tested with the windshield and/or other glazing in
place. Commenters also addressed requirements for multi-stage vehicles.

June 2008 Congressional Hearing and Letters

    On June 4, 2008. the Subcommittee on Consumer Affairs, Insurance,
and Automotive Safety of the Senate Commerce, Science and
Transportation Committee held an oversight hearing on passenger vehicle
roof strength. Former NHTSA Deputy Administrator James Ports testified
at the hearing. At the hearing and also in a subsequent letter to
Secretary Peters dated June 19, 2008, several Senators encouraged the
agency to extend the July 1, 2008 date for completing a final rule.
They encouraged the agency to ensure a rulemaking that would maximize
vehicle safety and significantly reduce deaths and injuries for drivers
and passengers in vehicle rollover crashes.
    Several Senators encouraged NHTSA to consider a two-sided test
requirement and a higher SWR requirement than the proposed 2.5 level,
and to provide detailed information concerning alternatives considered
by the agency. They also raised concerns about the use of 50th
percentile adult male test dummies instead of ones representing taller
occupants. The Senators also expressed significant concerns about
possible preemption of common law tort actions, and asked that such a
provision not be included in the final rule.
    In a letter to Secretary Peters dated June 27, 2008, Chairman Henry
Waxman of the House Committee on Oversight and Government Reform,
raised similar concerns to those of the Senators.

New IIHS Roof Strength Consumer Information Program

    On February 19, 2009, IIHS met with NHTSA representatives to
provide the agency information about a new roof strength consumer
information program that the organization is initiating. IIHS believes
the FMVSS No. 216 test procedure is a meaningful structural assessment
of real-world rollover crashworthiness as shown by recent studies it
has conducted showing that improved roof strength reduces injury risk
in midsize SUVs and small cars. That organization indicated that the
boundary for a good rating in the IIHS program will be a SWR of 4.0 in
a one-sided platen test similar to the existing FMVSS No 216 test
procedure. IIHS indicated that it does not plan to rate the larger,
heavier light vehicles, i.e., ones likely to have GVWRs greater than
2,722 kilograms (6,000 pounds).
    On March 24, 2009, IIHS issued a press release announcing a number
of details about its new rating system, including ratings for 12 small
SUVs. For an acceptable rating, the minimum SWR is 3.25. A marginal
rating value is 2.5. Anything lower than that is rated as poor. In
order to earn IIHS's ``top safety pick'' award for 2010, vehicles will
need to have a good roof strength rating, i.e., SWR of 4.0. Of the 12
small SUVs tested by IIHS, eight were rated by that organization as
good, five as acceptable, two as marginal, and one as poor.

VI. Agency Decision and Response to Comments

a. Primary Decisions

1. Basic Nature of the Test Requirements--Quasi-Static vs. Dynamic
Tests
    As noted above and discussed in detail in the NPRM, we developed
our proposal to upgrade roof crush resistance requirements after
considerable analysis and research, including conducting a research
program to examine potential methods for improving the roof crush
resistance requirements. The agency testing program included full
vehicle dynamic rollover testing, inverted vehicle drop testing, and
comparing inverted drop testing to a modified FMVSS No. 216 test. After
considering the results of the testing and other available information,
the agency concluded that the quasi-static procedure provides a
suitable representation of the real-world dynamic loading conditions,
and the most appropriate one on which to focus our upgrade efforts.
    We did not propose a dynamic test procedure in either the NPRM or
the SNPRM. We did discuss in the NPRM a number of types of dynamic
tests and why we were not including them in the proposal. We stated our
belief that the current quasi-static test procedure is repeatable and
capable of simulating real-world deformation patterns. We also stated
that we were unaware of any dynamic test procedure that provides a
sufficiently repeatable test environment.
    Consumer advocacy organizations and a number of other commenters
argued that it is not enough to upgrade the current quasi-static
requirement, and

that a dynamic test requirement is needed. While specific
recommendations varied, one was for the agency to adopt an upgraded
quasi-static requirement now, and to proceed with further rulemaking at
this time for a dynamic test.
    Advocates stated that the proposed quasi-static test cannot
demonstrate actual roof crush resistance in rollover crashes and that a
dynamic test would address occupant kinematics and injury responses in
actual rollover crashes. Public Citizen stated that a dynamic test
could simultaneously evaluate the performance of seat belts, doors,
ejection mitigation and the roof. A number of commenters made specific
recommendations concerning the type of dynamic test that the agency
should propose, e.g., with a number recommending the FMVSS No. 208
dolly test and/or the Jordan Rollover System (JRS) test.
    As part of our considering the merits of a dynamic test and
comments on the JRS, on February 23, 2007, NHTSA representatives met
with Xprts, LLC (Xprts) at its test facility in Goleta, CA, to view and
discuss the device. CAS and Center for Injury Research (CFIR) also
submitted additional test data to the agency using the JRS.
    We note that the agency is also aware of tests used by
manufacturers to assess a vehicle's rollover performance during vehicle
development and conditions they are designed to represent such as the
curb trip, soil trip, the bounce over, etc.\9\
---------------------------------------------------------------------------

    \9\ Viano D., Parenteau C., ``Rollover Crash Sensing and Safety
Overview,'' SAE International, 2004-01-0342.
---------------------------------------------------------------------------

    As noted earlier in this document, rollover crashes are complex and
chaotic events. Rollovers can range from a single quarter turn to eight
or more quarter turns, with the duration of the rollover crash lasting
from one to several seconds. The wide range of rollover conditions
occurs because these crashes largely occur off road where the vehicle
motion is highly influenced by roadside conditions.
    The variety and complexity of real-world rollover crashes create
significant challenges in developing dynamic tests suitable for a
Federal motor vehicle safety standard. Rollover crash tests can have an
undesirable amount of variability in vehicle and occupant kinematics.
    In assessing whether a potential dynamic test would be appropriate
for a Federal motor vehicle safety standard, the agency must consider
such issues as (1) whether the test is representative of real-world
crashes with respect what happens to the vehicle and any specified test
dummies; (2) for the specific aspect of performance at issue, whether
the test is sufficiently representative of enough relevant real-world
crashes to drive appropriate countermeasures and, if not, the number
and nature of necessary tests to achieve that purpose; (3) whether the
test is repeatable and reproducible so that the standard will be
objective; and (4) whether the test dummies to be specified are
biofidelic for the purposes used.
    We have reviewed the comments recommending a dynamic test and are
including our analysis of those comments in an appendix to this
document. NHTSA appreciates the information and data that have been
provided on this subject. We decline, however, to pursue a dynamic test
as part of this rulemaking, or to initiate at this time a separate
rulemaking for a dynamic test.
    As noted above, we explained in the NPRM that we were unaware of
any dynamic test procedure that provides a sufficiently repeatable test
environment. After reviewing the public comments and for reasons
discussed in the appendix, we continue to take that position. While
some commenters argued that certain procedures are repeatable, the
agency was not persuaded by the arguments and data they presented.
Moreover, for reasons discussed in the appendix, there are significant
issues associated with each of the cited dynamic test procedures
related to possible use in a Federal motor vehicle safety standard.
    Also of importance for this rulemaking, even if NHTSA were to
identify a particular dynamic test procedure, among the many known to
be available, as likely to be suitable for assessing roof crush
resistance (something we have not been able to do thus far), we would
need additional years of research to evaluate and refine, as necessary,
the procedure to develop a proposal, including evaluating it in the
context of the current vehicle fleet. It is also not known whether any
dynamic test requirement that might be identified by NHTSA's research
would produce significant additional benefits beyond those that will be
produced by the substantial upgrade of the quasi-static procedure that
we are adopting in this rule.
    NHTSA agrees, however, with pursuing a dynamic test as our ultimate
goal. We would like to have one for rollover crashes just as we do for
front and side crashes. Unfortunately, we cannot adopt or even propose
one now because of issues related to test repeatability, a dummy, and
lack of injury criteria. We are pursuing further research for a dynamic
test, but we expect that it will take a number of years to resolve
these issues. In the meantime, we do not want to delay a significant
upgrade of FMVSS No. 216 that will save 135 lives each year.
2. Vehicle Application
    FMVSS No. 216 currently applies to passenger cars, and to
multipurpose passenger vehicles, trucks and buses with a GVWR of 2,722
kilograms (6,000 pounds) or less. In our August 2005 NPRM, in addition
to proposing upgraded performance requirements, we proposed to extend
the application of the standard to vehicles with a GVWR of up to 4,536
kilograms (10,000 pounds). We proposed to permit vehicles manufactured
in two or more stages, other than chassis-cabs, to be certified to the
roof crush requirements of FMVSS No. 220, instead of FMVSS No. 216. We
stated that we believed that the requirements of FMVSS No. 220 appeared
to offer a reasonable avenue to balance the desire to respond to the
needs of multi-stage manufacturers and the need to increase safety in
rollover crashes.
    The commenters generally supported extending the application of
FMVSS No. 216 to vehicles with a GVWR of up to 4,536 kilograms (10,000
pounds). The National Transportation Safety Board (NTSB) stated that
heavier vehicles such as 12- and 15-passenger vans, not currently
subjected to the standard, are experiencing patterns of roof intrusion
greater than vehicles already subject to the requirements. That
commenter also cited two investigations it conducted concerning the
safety need for vehicles between 6,000 and 10,000 pounds GVWR to meet
roof crush resistance requirements.
    We received a number of comments concerning requirements for multi-
stage vehicles and vehicles with altered roofs, including ones from
Advocates, the National Truck Equipment Association (NTEA), the
Recreation Vehicle Industry Association (RVIA) and the National
Mobility Equipment Dealers Association (NMEDA). The concerns and
recommendations of these commenters varied considerably. We discuss and
address the comments later in this document. For purposes of this more
general section concerning applicability, we note that we are providing
a FMVSS No. 220 option for some but not all multi-stage vehicles and
for vehicles which are altered in certain ways to raise the height of
the roof. We also note that, for reasons discussed in that section, we
are excluding a narrow

category of multi-stage trucks from FMVSS No. 216 altogether.
    Subject to the limited exceptions/alternatives/exclusions noted in
the previous paragraph or already included in FMVSS No. 216, and for
the reasons discussed in the NPRM and in this document, we are
extending the application of the standard to vehicles with a GVWR of up
to 4,536 kilograms (10,000 pounds).\10\
---------------------------------------------------------------------------

    \10\ This final rule will address the NTSB's recommendation H-
03-16, to include 12- and 15-passenger vans in FMVSS No. 216, to
minimize the extent to which survivable space is compromised in the
event of a rollover accident.
---------------------------------------------------------------------------

3. Single-Sided or Two-Sided Tests
    Under the current version of FMVSS No. 216, vehicles must meet the
standard's requirements for both the driver and passenger sides of the
vehicle. Thus, roof crush resistance protection is required for both
the driver and passenger sides of the vehicle. The standard specifies a
single-sided test. While a vehicle must meet the standard's test
requirements, regardless of whether it is tested on the driver or
passenger side, a particular vehicle is tested on only one side.
    As discussed in the NPRM, a number of commenters on our 2001 RFC
suggested that the agency specify a two-sided test requirement, i.e., a
requirement that each vehicle must meet the standard's test
requirements when tested sequentially, first on one side of the
vehicle, and then on the other side. Commenters making this
recommendation included Public Citizen and CFIR. The commenters stated
that vehicle occupants on the far side of the rollover have a much
greater risk of serious injury than occupants on the near side,\11\ and
argued that a two-sided requirement is needed to protect far side
occupants.
---------------------------------------------------------------------------

    \11\ Near side is the side toward which the vehicle begins to
roll and the far side is the trailing side of the roll.
---------------------------------------------------------------------------

    In the NPRM, the agency summarized the results of six two-sided
tests it had conducted in light of those comments. The testing sought
to evaluate the strength of the second side of the roof of vehicles
whose first side had already been tested. In this testing, after the
force was applied to one side of the roof over the front seat area of a
vehicle, the vehicle was repositioned and force was then applied on the
opposite side of the roof over the front seat area. In performing these
tests on both sides of a vehicle, the agency used the platen angle
currently specified in FMVSS No. 216 (5 degree pitch forward and 25
degree rotation outward, along its lateral axis). We concluded that the
strength of the roof on the second side of some vehicles may have been
increased or decreased as a result of the deformation of the first side
of the roof. The agency indicated that it planned to conduct further
research before proposing rulemaking in this area.
    In commenting on the NPRM, a number of consumer advocacy
organizations and other commenters strongly supported a two-sided test
requirement. These commenters included, among others, Public Citizen,
CFIR, CAS, and Advocates. Supporters of a two-sided test requirement
argued that more damage occurs to the far (or trailing) side of the
vehicle in a rollover crash, and a two-sided test would better reflect
this real-world intrusion. They further argued that when the near side
roof and windshield are compromised in a rollover, the far side will
not be able to withstand the forces of the event, and, consequently,
facilitate roof collapse. ARCCA, Inc., Consumers Union, and Safety
Analysis and Forensic Engineering (SAFE) suggested a two-sided test
would simulate the impact that occurs in the majority of rollover
incidents.
    In light of the substantial interest in a two-sided test
requirement, NHTSA expanded the series of two-sided roof crush tests
discussed in the NPRM. In our January 2008 SNPRM, we explained that we
had, by that time, conducted a total of 26 sequential two-sided tests,
and announced that we were releasing these data to the public in
conjunction with the SNPRM.
    We stated in the SNPRM that the two-sided test results showed the
first side test generally produces a weakening of the structure. This
was shown by the fact that the recorded SWR for the second side was
generally lower than for the first side. On average, the peak strength
for the second side was reduced by 8.7 percent. However, for several of
the vehicles, we observed considerably higher reductions in peak
strength. Of the 26 vehicles that had been tested by that time,
excluding the Chevrolet Express, six experienced reductions in strength
of 19 percent or greater. We excluded the Chevrolet Express because of
a test anomaly.\12\
---------------------------------------------------------------------------

    \12\ Between the first and second side tests, the front door on
the tested side was opened. Because of damage to the vehicle during
the first side test, the door would not properly close. The door was
clamped until the latch engaged, locking the door in place. This may
have compromised the structural integrity of the roof and reduced
the measured peak load on the second side.
---------------------------------------------------------------------------

    With respect to two-sided vehicle testing, we stated that we
believed that the post-NPRM tests provided the agency with sufficient
additional information for the agency to consider a two-sided test
requirement for the final rule. We stated that we would evaluate both
the single-sided and two-sided testing alternatives for the final rule,
and requested comments to help us reach a decision on that issue.
Comments
    In commenting on the SNPRM, a number of consumer advocacy
organizations continued to strongly support a two-sided test
requirement. Public Citizen stated that in a vast majority of rollover
cases, the injured party was typically seated on the far side, that is,
the side of the second impact. It argued that it is not possible to
upgrade FMVSS No. 216 without a two-sided test requirement. Some
commenters argued, as they had in commenting on the NPRM, that they
believe SAFETEA-LU requires a two-sided test.
    IIHS stated that while it supports any changes that would increase
the level of roof strength of the vehicle fleet, it has no real-world
data to address the potential benefits of two-sided testing. It stated
that a single-sided test with a higher SWR may be more effective at
promoting robust roof designs than a two-sided test with a lower SWR
requirement.
    The Alliance stated that it believes the agency has provided
insufficient justification for two-sided testing. It stated that the
agency has not provided analysis demonstrating that two-sided testing
relates to real-world safety.
    The Alliance also expressed concern that two-sided testing would
amplify variability and repeatability problems. That organization
argued that the agency's limited repeatability testing for a potential
two-sided requirement indicates poor repeatability in SWR between the
first and second side tests for the same vehicle. The Alliance cited
agency tests of the Lincoln LS and Buick LaCrosse.
    According to the Alliance, these differences may be due solely to
lack of test procedure repeatability and test lab reproducibility,
rather than any real weakening or strengthening of the roof structure
due to the first side test. That commenter stated that in a two-sided
scenario, the deformed shape of a vehicle tested for roof strength on
one side between any two tests is not identical. The starting point for
the roof-strength testing on the second side is therefore, according to
the Alliance, inherently different and results in substantial
variability in measured roof strength.
    AIAM stated that based on the information and analysis provided by

the agency regarding the two-sided test, it believes that the test
shows enough potential to merit further consideration by the agency.
AIAM argued that additional analysis would be needed before it could
provide a preferred regulatory approach, but indicated that the two-
sided approach would more directly address the multiple roof contact
weakening phenomenon.
Agency Response
    After carefully considering the comments and available information,
we have decided, for the reasons discussed below, to adopt a two-sided
test requirement.
    In responding to the comments, we begin by addressing the argument
raised by some commenters that SAFETEA-LU requires a two-sided test.
Public Citizen stated that the agency has ``ignored the express
requirement of a two-sided test.'' That organization cited the
statutory language requiring NHTSA to upgrade FMVSS No. 216 related to
roof strength ``for driver and passenger sides.'' (Emphasis added by
Public Citizen.)
    As discussed earlier in this document, under the current version of
FMVSS No. 216, vehicles must meet the standard's requirements for both
the driver and passenger sides of the vehicle, i.e., a vehicle must
meet the standard's test requirements regardless of whether it is
tested on the driver or passenger side. Thus, while the standard
specifies a single-sided test, roof crush resistance protection is
required for both the driver and passenger sides of the vehicle.
Similarly, upgrading the current performance requirements so that
vehicles must provide protection at a significantly higher SWR under a
single-sided test procedure would result in upgraded protection for
both the driver and passenger sides. Thus, while we understand the
safety arguments raised by Public Citizen and other commenters favoring
a two-sided test, we believe that the language in SAFETEA-LU does not
mandate a two-sided test requirement, only that upgraded protection be
provided for both the driver and passenger sides.
    We also note that the issue of whether to adopt a two-sided test is
related to the decision of what stringency to adopt. For any baseline
single-sided test requirement at a particular SWR, either increasing
the SWR for the single-sided test or adding a two-sided test
requirement at the same SWR would represent an increase in stringency.
Therefore, in reaching a decision on these issues, we have considered
them together.
    To help evaluate the merits of a two-sided test requirement, the
agency analyzed 1997 through 2006 NASS-CDS rollover crash data,
involving restrained occupants.\13\ Only vehicles that overturned and
experienced 2 or more quarter turns were included. This study included
4,030 NASS-CDS investigated vehicles, and excluded convertibles and
vehicles that had a concentrated loading due to a collision between a
fixed object (pole or tree) and the roof.
---------------------------------------------------------------------------

    \13\ See report Evaluation of 2 Side Roof Crush Testing placed
in the docket with this notice.
---------------------------------------------------------------------------

    The data were analyzed for differences in injury risk for the near
and far side occupants and also to ascertain any disparity in the
amount of roof intrusion. For all rollovers involving two or more
quarter turns, the data showed that there are a similar number of near
and far side occupants involved in the event. A further review of the
injury outcomes showed that the injuries to far side occupants occur at
a slightly higher frequency than injuries to near side occupants.
    The occupant injury data were further analyzed to determine whether
the relative proportion of near and far side injured occupants varied
with the amount of roof intrusion. The injury outcomes for occupants in
vehicles with less than 12 cm (5 inches) of near side roof intrusion
show higher frequency of injury for the far side occupant at the
various injury levels. The outcomes for injured occupants in vehicles
with 12 cm (5 inches) or greater near side intrusion have similar
percentages of severe injuries between near and far occupants. Based on
this analysis, the data indicate there may be some higher risk for far
side occupants at lower levels of intrusion; however, none of the
results was statistically significant.
    The analysis investigated the difference in roof intrusion between
the near and far side of the vehicle that experienced two quarter turns
or more. For the 4,030 NASS-CDS vehicles, there was a weighted average
maximum vertical intrusion of 7.9 cm (3.1 inches) on the near side and
10.9 cm (4.3 inches) on the far side of the rollover-involved vehicle.
The far side of the vehicle averaged 3 cm (1.2 inches) more vertical
intrusion than the near side.
    The analysis also investigated the intrusion difference between the
near and far side grouped by the severity of the rollover. (Severity of
the rollover was defined by single or multiple roof-to-ground
contacts). The data showed a 3 cm (1.2 inch) bias toward the far side
intrusion, independent of the severity of the rollover. For example,
vehicles experiencing five or more quarter turns had 9.2 cm (3.6
inches) of near-side intrusion compared to 12.2 cm (4.8 inches) of far-
side intrusion. The analysis concluded for crashes with multiple roof-
to-ground contacts (or severe rollovers), there is a statistically
insignificant bias on the far side.
    Since the publication of the SNPRM, the agency has conducted an
additional five tests \14\ as part of its evaluation, for a total of 31
two-sided tests.\15\ The test results for all 31 two-sided tests are
summarized in Appendix B of this document.
---------------------------------------------------------------------------

    \14\ The test reports for the additional vehicle tests conducted
by NHTSA are being made available to the public through the agency's
internet vehicle crash test database. We are placing a memorandum in
the docket which provides the Web address for that database and
lists the vehicle models and test numbers that are needed to
reference the information in the database. The agency incorporates
by reference these test reports as part of the record for this
rulemaking.
    \15\ We note that we also conducted a test of a Smart ForTwo.
However, we did not include these test results as part of our
evaluation because the vehicle is not typical of a significant
number of vehicles in the fleet.
---------------------------------------------------------------------------

    On average, the peak strength for the second side was reduced by
8.4 percent. This reduction in strength is consistent with our NASS-CDS
analysis, showing a slight increase of intrusion on the second side.
This also may explain the increased risk to injury for far side
occupants. In all the tests, the windshield fractured during the first
side test and there was not a catastrophic collapse of the roof on the
second side.
    In general, there was a good correlation in peak strength between
the first and second side. The agency did test four vehicles that
resulted in increased strength on the second side. However, for several
of the vehicles, we observed considerably higher reductions in peak
strength. Of the 31 vehicles tested, again excluding the Chevrolet
Express, seven experienced reductions in strength of 19 percent or
greater. The two-sided testing conducted by NHTSA indicated an average
difference of approximately 7.1 percent lower peak force for the second
side in vehicles under 2,722 kilograms (6,000 pounds) GVWR and 14.9
percent lower peak force for the second side in vehicles over 2,722
kilograms (6,000 pounds) GVWR.
    We have decided to adopt a two-sided test in light of several
considerations. First, we believe a two-sided test is more
representative of the higher severity rollover crashes in which a
vehicle experiences multiple quarter turns. In such crashes, the
vehicles sometimes experiences a significant impact on one side of the
vehicle and,

as the vehicle continues to turn, another significant impact on the
other side of the vehicle. A two-sided test will help ensure that the
impact on the first side of the vehicle does not cause excess damage
that will prevent the vehicle from providing protection during the
impact on the second side of the vehicle.
    Moreover, as discussed in the FRIA, the greater stringency
associated with a two-sided test requirement will provide greater
benefits.
    While we recognize that a two-sided test requirement affects the
stringency of the standard, as compared to a single-sided test
requirement at the same SWR, we believe that it does not raise concerns
related to test procedure repeatability and test lab reproducibility.
    In addressing this issue, we note that the test conducted on the
second side is identical to the test conducted on the first side. Thus,
the second side test by itself is repeatable and reproducible, for the
same reasons the first side test is repeatable and reproducible.
    As noted by the Alliance, the ``starting point'' for the second
side test is different than for the first side test in that the vehicle
may have experienced damage during the first side test. However, it is
the purpose of a two-sided test requirement to limit such damage, to
the extent such damage would prevent compliance with the standard's
performance requirements during the second side test.
    As to the Lincoln LS and Buick Lacrosse repeat tests cited by the
Alliance, the change in peak SWR between the first and second side test
was -21.3 percent and -8.7 percent for the two Lincoln LS vehicles
tested, and -13.5 percent and -3.4 percent for the two Buick Lacrosse
vehicles tested. For the Lincoln LS, there was good correlation between
the load-deformation curves on the first side in the two tests.
However, on the second side, the load-deformation curves diverge prior
to the peak SWR. Further, in one Lincoln LS test, the second side
correlated well with the first side. The other test did not show the
same correlation on the second side, which led us to believe internal
structural damage to the roof during the first side test was the cause.
With respect to the Buick Lacrosse, the agency identified a pre-test
windshield crack as the likely reason for the difference in outcome
between the two tests. The load-deformation curves for the first side
did not reach the same peak load; however, there is good correlation on
the second side. Thus, we believe the differences relate to vehicle
performance instead of test procedure issues.
    It is important to note that the Lincoln LS and Buick Lacrosse
vehicles were not subject to an FMVSS incorporating a two-sided
requirement or an SWR requirement above 1.5, so they were not designed
to meet such a requirement (two-sided test requirement at the tested
SWR). Manufacturers can ensure that a vehicle meets a two-sided test
requirement by designing it so that they will be able to meet the
second-side test despite whatever damage may occur in the first side
test. As a general matter, the greater the structural damage that
occurs in the first-side test, the greater the variability one would
expect in the second-side test. We note that the performance
requirement is not expressed in terms of the percentage difference in
damage between the first-side test and the second test; instead, the
vehicle must meet the same specified performance criteria in both
tests. We also note that the first-side test is conducted only up to
the SWR specified in the standard.
    Finally, we note that issues raised by commenters concerning
varying platen angle and size for the second-side test are addressed
later in this document in the section addressing aspects of the test
procedure.
4. Upgraded Force Requirement--Specified Strength to Weight Ratio (SWR)
    As discussed earlier, FMVSS No. 216 currently requires that the
lower surface of the test platen not move more than 127 mm (5 inches),
when it is used to apply a force equal to 1.5 times the unloaded
vehicle weight to the roof over the front seat area. In the NPRM, the
agency proposed to require that the roof over the front seat area
withstand a force increase equal to 2.5 times the unloaded weight of
the vehicle, and to eliminate the 22,240 Newton (5,000 pound) force
limit for passenger cars.
    NHTSA explained that it believes that FMVSS No. 216 could protect
front seat occupants better if the applied force requirement reduced
the extent of roof crush occurring in real world crashes. That is, the
increased applied force requirement would lead to stronger roofs and
reduce the roof crush severity observed in real world crashes. We
observed that in many real-world rollovers, vehicles subject to the
requirements of FMVSS No. 216 experienced vertical roof intrusion
greater than the test plate movement limit of 127 mm (5 inches).
    In explaining the proposed 2.5 value for SWR, the agency noted that
it previously conducted a study \16\ (Rains study) that measured peak
forces generated during quasi-static testing under FMVSS No. 216 and
under Society of Automotive Engineers (SAE) J996 inverted drop testing.
In the Rains study, nine quasi-static tests were first conducted. The
energy absorption was measured and used to determine the appropriate
corresponding height for the inverted drop conditions. Six of the
vehicles were then dropped onto a load plate. The roof displacement was
measured using a string potentiometer connected between the A-pillar
and roof attachment and the vehicle floor. The peak force from the drop
tests was limited to only the first 74 mm (3 inches) of roof crush
because some of the vehicles rolled and contacted the ground with the
front of the hood. Similarly, the peak quasi-static force was limited
during the first 127 mm (5 inches) of plate movement.
---------------------------------------------------------------------------

    \16\ Glen C. Rains and Mike Van Voorhis, ``Quasi Static and
Dynamic Roof Crush Testing,'' DOT HS 808-873, 1998.
---------------------------------------------------------------------------

    This report showed that for the nine quasi-static tests, the peak
force-to-weight ratio ranged from 1.8 to 2.5. Six of these vehicle
models were dropped at a height calculated to set the potential energy
of the suspended vehicle equal to the static tests. For these dynamic
tests, the peak force-to-weight ratio ranged from 2.1 to 3.1. In sum,
the agency tentatively concluded that 2.5 was a good representation of
the observed range of peak force-to-weight ratio.
    As to eliminating the 22,240 Newton force limit for passenger cars,
the agency noted that the limit was included when the standard was
first issued. The effect of the limit was that passenger cars weighing
more than 1,512 kilograms (3,333 pounds) were subjected to less
stringent requirements. The purpose of the limit was to avoid making it
necessary for manufacturers to redesign large cars that could not meet
the full roof strength requirements of the standard.\17\ At the time,
the agency believed that requiring larger passenger cars to comply with
the full (1.5 times the unloaded vehicle weight) requirement would be
unnecessary because heavy passenger cars had lower rollover propensity.
However, as discussed in the NPRM, the agency tentatively concluded
that occupants of passenger cars weighing more than 1,512 kilograms
(3,333 pounds) are sustaining rollover-related injuries and that those
cars should be able to comply with the proposed requirements.
---------------------------------------------------------------------------

    \17\ See 54 FR 46276.

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

    The agency stated in the NPRM that it believed that manufacturers
would comply with the upgraded standard by strengthening reinforcements
in roof pillars, by increasing the gauge of steel used in roofs or by
using higher strength materials.
    In the SNPRM, we noted that we had been carefully analyzing the
numerous comments received in response to the proposal, and the various
additional vehicle tests conducted after publication of the NPRM. We
invited comments on how the agency should factor in this new
information into its decision. We stated that while the NPRM focused on
a specified force equivalent to 2.5 times the unloaded vehicle weight,
the agency could adopt a higher or lower value for the final rule.
    In the SNPRM, we observed from the recent vehicle testing (focusing
on the single-sided test results) that the range of SWRs for vehicles
with a GVWR of 2,722 kilograms (6,000 pounds) or less tended to be
higher than the range of SWRs for vehicles with a GVWR greater than
2,722 kilograms (6,000 pounds). The SWR of many late model vehicles
with a GVWR of 2,722 kilograms (6,000 pounds) or less was substantially
higher than the 2.5 value the agency focused on in the NPRM.
Conversely, only two vehicles we tested with a GVWR greater than 2,722
kilograms (6,000 pounds) exceeded the 2.5 value.
    We noted in the SNPRM that the PRIA had examined the proposed SWR
of 2.5 and the alternative SWR of 3.0 times the unloaded vehicle
weight. The agency included in the SNPRM discussion and analysis
concerning a number of factors expected to change the estimated
impacts, and sought comments concerning impacts of SWR levels of 2.5,
3.0 and 3.5.
Comments on the NPRM
    In general, vehicle manufacturers supported an SWR of 2.5, while
safety advocacy groups recommended a more stringent standard with the
majority supporting a 3.5 SWR requirement.
    Vehicle manufacturers, including General Motors Corporation (GM),
Ford Motor Company (Ford), DaimlerChrysler Corporation,\18\ Porsche
Cars North America (Porsche), Toyota Motor North America (Toyota), and
Nissan North America (Nissan), and the Alliance supported the proposed
2.5 SWR level, with caveats about sufficient leadtime and other
requested changes to the test procedure, but expressed concern about
raising the SWR further. The Alliance cautioned against increasing the
SWR beyond 2.5 due to the potential adverse effects of increased mass.
It stated that recommendations in the docket for higher levels did not
attempt to account for the potential effect on the static stability
factor (SSF) of adding structure necessary to comply with higher
standards.
---------------------------------------------------------------------------

    \18\ In August 2007, Daimler and Chrysler separated. All
comments submitted to the agency prior to that date will be noted in
this document as DaimlerChrysler. Mercedes-Benz USA and Chrysler LLC
submitted comments separately afterwards and will be referenced
accordingly.
---------------------------------------------------------------------------

    Commenters supporting a 3.5 SWR included Lipsig, Shapey, Manus &
Moverman (LSMM), Consumers Union, Center for the Study of Responsive
Law (CSRL), Mr. Sances, Perrone Forensic Consulting (Perrone), Ms.
Lawlor, Mr. Clough, Xprts, Mr. Nash, Mr. Friedman, and Forensic
Engineering (FEI). Consumers Union, LSMM, Ms. Lawlor, Mr. Clough, and
Mr. Sances supported a 3.5 SWR based on, among other things, the
performance of the Volvo XC90. Commenters stated that the Volvo XC90
has heightened roof strength resistance through light-weight materials
making it possible to avoid any unnecessary increases in vehicle weight
which could adversely affect rollover propensity. In supporting more
stringent roof crush resistance requirements, the CSRL stated that
NHTSA should consider using its technology-forcing authority.
    Several commenters supported an SWR of 4.0 or higher. These
commenters included Mr. Slavik, ARCCA, Technical Services, and FEI. The
commenters suggested that higher strength steel alloy, changes to the
cross sectional thickness of roof components, and other design changes
would make increasing the SWR feasible and cost effective.
    In connection with arguments that the agency should base the level
of the standard on the performance of the Volvo XC90, Ford commented
that in considering the stringency of an SWR requirement, roof SWR does
not discriminate vehicles by roof strength. It noted that the roof
strength required to achieve a specific SWR depends on the vehicle's
unloaded vehicle weight (UVW). Ford stated that two vehicles with the
same SWR, but different UVWs, may have roof strength levels that are
actually several thousand pounds apart. That company argued that the
agency's 2.5 SWR proposal is very stringent. Ford stated that vehicle
roof designs are essentially the same for all passenger carrying
vehicles, and that A pillars are A pillars and B pillars are B pillars,
regardless of vehicle type, i.e., the constraints on a roof system
design are applicable to all affected vehicles. That company argued
that because a particular vehicle can achieve a roof SWR of 3.5,
because it has a lower UVW as compared to a full size pickup, does not
mean that 3.5 should be the regulatory requirement.
Comments on the SNPRM
    In commenting on the SNPRM, vehicle manufacturers continued to
support an SWR of 2.5, with safety advocacy groups recommending a more
stringent requirement.
    The Alliance recommended that all vehicles should be held to the
same requirements and that a separate requirement should not be
afforded for heavy vehicles. Mercedes-Benz suggested that, for a two-
sided test requirement, the SWR on the second side should be lower than
what would be required for the first side. This would reflect the lower
force levels in a rollover that it said the second side would
experience.
    IIHS supported raising the SWR to 3.0 or higher in a one-sided
test. IIHS stated that its new analysis justifies such a requirement.
Agency Decision and Response
    After carefully considering the comments and available information,
and for the reasons discussed below, we have decided to adopt an SWR
requirement of 3.0 for vehicles with a GVWR of 2,722 kilograms (6,000
pounds) or less, and 1.5 for vehicles with a GVWR greater than 2,722
kilograms (6,000 pounds).
    While this rulemaking involves a number of key decisions, the
selection of an SWR requirement is the most important one for both
costs and benefits. Our analysis, presented in detail in the FRIA,
shows that for the alternatives we evaluated, benefits in terms of
reduced fatalities continue to rise with higher SWR levels due to
reduced intrusion. The benefits continue to rise because, for vehicles
designed to have higher SWR levels, the vehicle roofs experience less
intrusion in higher severity crashes. However, costs also increase
substantially with higher SWR levels, so NHTSA must select the
appropriate balance of safety benefits to added costs.
    Under the Safety Act, NHTSA must issue safety standards that are
both practicable and meet the need for motor vehicle safety. 49 U.S.C.
30111(a). The agency considers economic factors, including costs, as
part of ensuring that standards are reasonable, practicable, and
appropriate.
    In Motor Vehicle Manufacturers Association v. State Farm, 463 U.S.
29, 54-55 (1983), the Supreme Court indicated that the agency must, in
making decisions about safety

standards, consider reasonableness of monetary and other costs
associated with the standard. It stated, however, that ``(i)n reaching
its judgment, NHTSA should bear in mind that Congress intended safety
to be the preeminent factor under the Motor Vehicle Safety Act:''

    The Committee intends that safety shall be the overriding
consideration in the issuance of standards under this bill. The
Committee recognizes * * * that the Secretary will necessarily
consider reasonableness of cost, feasibility and adequate leadtime.
S. Rep. No. 1301, at 6, U.S. Code Cong. & Admin. News 1966, p. 2714.
    In establishing standards the Secretary must conform to the
requirement that the standard be practicable. This would require
consideration of all relevant factors, including technological
ability to achieve the goal of a particular standard as well as
consideration of economic factors. Motor vehicle safety is the
paramount purpose of this bill and each standard must be related
thereto. H.Rep. No. 1776, at 16.

    Thus, in making our decision concerning SWR, we are guided by the
statutory language, legislative history, and the Supreme Court's
construction of the Safety Act, as well as by the specific requirement
in SAFETEA-LU for us to upgrade FMVSS No. 216 relating to roof strength
for driver and passenger sides for motor vehicles with a GVWR of not
more than 4,536 kilograms (10,000 pounds). We consider both costs and
benefits, bearing in mind that Congress intended safety to be the
preeminent factor under the Safety Act.
    As indicated above, while benefits continue to rise with higher SWR
levels, costs also increase substantially. The challenge is to push to
a level where the safety benefits are still reasonable in relation to
the associated costs. As part of this, we consider issues related to
cost effectiveness. The agency's analysis of cost effectiveness is
presented in the FRIA and summarized in this document.
    Another important factor in the selection of the SWR requirements
is that there are much higher costs relative to benefits associated
with any level SWR requirement for vehicles with a GVWR greater than
2,722 kilograms (6,000 pounds) as compared to the lighter vehicles
currently subject to the standard.
    There are a number of reasons for this differential between heaver
and lighter vehicles. The absolute strength needed to meet a specific
SWR is a function of the vehicle's weight. By way of example, to meet a
2.0 SWR, a vehicle that weighs 1,360 kilograms (3,000 pounds) must have
a roof structure capable of withstanding 26,690 N (6,000 pounds) of
force, while a vehicle that weighs 2,268 kilograms (5,000 pounds) must
have a roof structure capable of withstanding 44,482 N (10,000 pounds)
of force. This means more structure or reinforcement are needed for the
heavier vehicle, which means more cost and weight. Moreover, vehicles
in the heavier category have not previously been subject to FMVSS No.
216, so they have not been required to meet the existing 1.5 SWR
single-sided requirement.
    At the same time, these heavier vehicles account for only a very
small part of the target population of occupants who might benefit from
improved roof strength. Only 5 percent of the fatalities in the overall
target population (33 in terms of a specific number) occur in vehicles
over 2,722 kilograms (6,000 pounds) GVWR. Ninety-five percent of the
fatalities (635 in terms of a specific number) occur in vehicles under
2,722 kilograms (6,000 pounds) GVWR. These differences reflect the fact
that there are far fewer vehicles in this category in the on-road
fleet, and may also reflect the vehicles' size and weight as well as
their frequency of use as working vehicles. Heavier vehicles generally
are less likely to roll over than lighter vehicles.
    We recognize the argument that all light vehicles should meet the
same SWR requirements, to ensure the same minimum level of protection
in a rollover crash. However, in selecting particular requirements for
a final rule, we believe that our focus must be on saving lives while
also considering costs and relative risk. What is necessary to meet the
need for safety and is practicable for one type or size of vehicle may
not be necessary or reasonable, practicable and appropriate for another
type or size of vehicle. Thus, to the extent the goal of establishing
the same SWR requirements for all light vehicles would have the effect
of either unnecessarily reducing the number of lives saved in lighter
vehicles or imposing substantially higher, unreasonable costs on
heavier vehicles despite their lesser relative risk, we believe it is
appropriate to adopt different requirements for different vehicles. We
also observe that because the same SWR requirement is significantly
more stringent for heavier vehicles than lighter vehicles (due to SWR
being a multiple of unloaded vehicle weight), establishing the same SWR
requirement for heavier vehicles is not simply a matter of expecting
manufacturers to provide the same countermeasures as they do for light
vehicles.
    Vehicles with a GVWR of 2,722 kilograms (6,000 pounds) or less.
    Our decision to adopt a 3.0 SWR requirement for vehicles with a
GVWR of 2,722 kilograms (6,000 pounds) or less, i.e., the vehicles
currently subject to the standard, reflects the higher life-saving
benefits associated with that requirement. It also reflects our
consideration of the test results of current vehicles. We believe the
high SWR levels that are currently being achieved for a range of light
vehicles demonstrate that manufacturers can achieve this SWR level for
these vehicles.
    An SWR requirement of 3.0 prevents about 66 percent more fatalities
than one at 2.5, 133 instead of 80. However, costs increase by a
considerably higher percentage, resulting in a less favorable cost per
equivalent life saved, $5.7 million to $8.5 million for 3.0 SWR as
compared to $3.8 million to $7.2 million for 2.5 SWR.
    In these particular circumstances, we believe that a 3.0 SWR
requirement is appropriate and the costs reasonable given the increased
benefits. While the cost per equivalent life saved is relatively high
compared to other NHTSA rulemakings, we conclude that the higher safety
benefits, the legislative mandate for an upgrade, the technical
feasibility of making roofs this strong, and the fact that these costs
are generally within the range of accepted values justify moving
NHTSA's roof crush standards to a 3.0 SWR for vehicles that have been
subject to the 1.5 SWR requirements.
    We decline, however, to adopt an even higher SWR requirement. In
considering higher SWR requirements at this level, costs continue to
increase at a considerably higher rate than benefits. The FRIA
estimates that while a 3.5 SWR requirement for these vehicles would
result in higher benefits, preventing 175 instead of 133 fatalities,
total costs would increase to $1.6 billion to $2.3 billion (about $800
million to $1.1 billion above the total costs for the 3.0 SWR
requirement) and the overall cost per equivalent life saved for these
vehicles would increase to $8.8 to $12.3 million. A 3.5 SWR requirement
would thus result in an approximate doubling of the costs beyond those
of a 3.0 SWR requirement, and deliver about \1/3\ more benefits.
    Vehicles with a GVWR greater than 2,722 kilograms (6,000 pounds)
and less than or equal to 4,536 kilograms (10,000 pounds).
    Vehicles with a GVWR greater than 2,722 kilograms (6,000 pounds)
are not currently subject to FMVSS No. 216 and, because of their
greater unloaded vehicle weight, these vehicles pose greater design
challenges. Moreover,

given the relatively small target population for these vehicles, the
benefits will necessarily be small regardless of the SWR selected.
    After considering our original proposal of a SWR of 2.5 and the
available information, we have concluded that a SWR of 1.5 is
appropriate for these heavier vehicles. The requirement we are adopting
is more stringent than the longstanding requirement that has applied to
lighter vehicles until this rulemaking because it is a two-sided
requirement. The FRIA estimates that two fatalities and 46 nonfatal
injuries will be prevented annually by this requirement. Because of the
high cost relative to the benefits for all of the alternatives for
these heavier vehicles, from the 1.5 SWR alternative and above, any
alternative we select would adversely affect the overall cost
effectiveness of this rulemaking (covering all light vehicles).
    We believe that a SWR of 1.5 is appropriate for these heavier
vehicles. Given the requirements of SAFETEA-LU, we need to ensure that
the standard results in improved real world roof crush resistance for
these vehicles. We decline, however, to adopt a SWR higher than 1.5 for
vehicles with a GVWR greater than 2,722 kilograms (6,000 pounds), given
the small additional benefits (4 additional lives saved) and
substantially higher costs. Adopting a SWR of 2.0 for these vehicles
would more than double the costs of this rule for these vehicles to
prevent 4 additional fatalities and 137 nonfatal injuries.
    Other issues related to strength requirements and SWR.
    As indicated above, the Alliance cautioned against increasing the
SWR beyond 2.5 for lighter vehicles due to the potential adverse
effects of increased mass. It stated that recommendations in the docket
for higher levels did not attempt to account for the potential effect
on the SSF of adding structure necessary to comply with higher
standards.
    We do not believe that it is necessary to account for that effect.
We note that the agency has considered a number of issues related to
added weight as part of the FRIA, including possible adverse effects to
safety. Based on our analysis, we believe that today's rule will not
result in adverse effects to safety as a result of added weight.
    For a number of reasons, including ones related to CAFE standards,
fuel prices, and rollover propensity, we believe manufacturers will
strive to minimize the weight impacts of added roof strength. While
there is a great deal of uncertainty regarding the actual changes that
manufacturers will initiate in response to this rule, there are
numerous ways to address both roof strength and rollover propensity
simultaneously. This final rule provides substantial leadtime within
which to choose among those ways and make design changes that avoid
adversely affecting that propensity. There is evidence from current
NCAP ratings that manufacturers are routinely doing so. Manufacturers
generally strive to maintain or improve their NCAP ratings to help
market their vehicles. The agency believes that this concern over NCAP
ratings would preclude a design strategy that unnecessarily increases
CG and degrades SSF. Further, agency testing of 10 redesigned vehicles
with higher roof strengths found that manufacturers had maintained SSF
levels while increasing roof strength in newly redesigned models.
    A detailed discussion of issues related to added weight and SSF is
included in the FRIA, and there is also additional discussion later in
this document.
    Mercedes-Benz suggested that, for a two-sided test requirement, the
SWR on the second side should be lower than what would be required for
the first side. According to Mercedes, this would reflect the lower
force levels in a rollover that it said the second side would
experience. However, as discussed above in the section on single-sided
or two-sided tests, the agency's analysis of NASS data indicates that
vehicles experience more intrusion on the far side (second side) of the
vehicle than the near side. Therefore, we decline to adopt a lower SWR
requirement for the second side. We note that the agency took into
account the costs and benefits of a two-sided test requirement with the
SWR at the same level for both sides.
    As to the issue raised by CSRL about safety standards that are
technology-forcing, that commenter did not provide specific information
concerning what it contemplated in this area. As part of the agency's
analysis of costs and benefits, we considered the use of advanced
higher strength and lighter weight materials. Our analysis assumes
significantly greater implementation and use of these advanced
materials.
    Finally, we note that several commenters suggested that the agency
use alternative approaches other than unloaded vehicle weight for
purposes of calculating SWR. Recommendations included using weight of
the vehicle plus two occupants, or GVWR plus two occupants. We decline
to change FMVSS No. 216's existing approach of using a multiple of
unloaded vehicle weight for calculating the force requirement that
applies to each vehicle. Using a weight higher than unloaded vehicle
weight would simply represent another means of increasing stringency
and would be equivalent to a requirement for a higher SWR. However, the
agency has already considered alternative higher SWR levels, as well as
a two-sided test requirement, which also represent an increase in
stringency. Thus, the other issues we have considered ensure an
appropriate level of stringency.
5. Performance Criteria--Headroom, Platen Travel, or Both
    In the NPRM, we proposed to replace the current limit on platen
travel (test plate movement) during the specified quasi-static test
with a requirement that the crush not exceed the available headroom. We
were concerned that the platen travel limit does not provide adequate
protection to front outboard occupants of vehicles with a small amount
of occupant headroom. We also stated that the current requirement may
impose a needless burden on vehicles with a large amount of occupant
headroom.
    Under our proposal, no roof component or portion of the test device
could contact the head or neck of a seated Hybrid III 50th percentile
adult male dummy during the specified test. We believed that this
direct headroom reduction limit would ensure that motorists receive an
adequate level of roof crush protection regardless of the type of
vehicle in which they ride. We included a definition of the term ``roof
component'' as part of the proposal.
    We noted a concern that there may be some low roofline vehicles in
which the 50th percentile Hybrid III dummy would have relatively little
available headroom when positioned properly in the seat. That is, we
were concerned that, in some limited circumstances, the headroom
between the head of a 50th percentile male dummy and the roof liner is
so small that even minimal deformation resulting from the application
of the required force would lead to test failure. We requested comments
on whether any additional or substitute requirements would be
appropriate for low roofline vehicles.
    In the NPRM, the agency estimated benefits based on post-crash
headroom, the only basis for which a statistical relationship with
injury reduction had been established. In our January 2008 SNPRM, we
explained that with additional years of available data, a statistically
significant relationship between intrusion and injury for belted
occupants had been established. A

study regarding this relationship was placed in the docket.\19\
---------------------------------------------------------------------------

    \19\ Strashny, Alexander, ``The Role of Vertical Roof Intrusion
and Post-Crash Headroom in Predicting Roof Contact Injuries to the
Head, Neck, or Face during FMVSS 216 Rollovers.''
---------------------------------------------------------------------------

    We also noted in the January 2008 SNPRM that in the most recent
agency testing, headroom reduction had been assessed using a head
positioning fixture (HPF) in lieu of a 50th percentile adult male
dummy. We stated that reports on these tests explain the procedure and
type of fixture used to assess headroom reduction, and that the test
reports were being made available to the public. We noted further that
the agency was considering whether this fixture should be specified in
the final rule.
Comments
    The agency received a variety of comments on the proposed headroom
reduction criterion.
    One group of commenters, including safety advocacy organizations,
generally supported adding a headroom reduction criterion but, in some
cases, argued that a platen travel criterion is also needed. Some of
these commenters also argued that these criteria should be made more
stringent to protect taller occupants.
    Another group of commenters, including vehicle manufacturers, urged
the agency to retain the current platen travel criterion instead of
adopting a headroom reduction criterion. They argued, among other
things, that using the headroom reduction criterion would add
unnecessary complexity to the test procedure and result in problems
related to repeatability and practicability.
    Specific issues raised by commenters include:
    Repeatability and practicability issues. Several commenters,
including the Alliance, DaimlerChrysler, GM, Ford, and Porsche, cited
concerns related to reliability and practicability of using a test
dummy for purposes of the FMVSS No. 216 quasi-static test.
DaimlerChrysler, Ford and GM stated that variations in test dummy
placement cause variability in the distance between the dummy head and
the roof side rails. In test results cited by GM, horizontal and
vertical variations of an inch or more occurred in the dummy's seating
position. GM stated that this variability is further complicated when
vehicles with different trim and seating options (cloth or leather,
manual or power adjusters) are provided using the same vehicle
architecture structure. It suggested that such options add to the
variability and make the proposed requirement of measuring roof crush
resistance with a seated Hybrid III dummy non-repeatable and
impracticable.
    Porsche also expressed concern with controlling unwanted movement
of the dummy with its roof crush test set-up. The Porsche roof crush
test procedure rotates the vehicle by 90 degrees because their platen
press applies a load parallel to the ground. The dummy is not fixed
into position and, as a result, would rotate and not be properly
positioned.
    Complexity. IIHS stated that relating the allowable amount of roof
crush in the quasi-static test to the headroom in specific vehicles is
a good concept but that, in practice, the agency's research tests have
not shown that replacing the 127 mm (5 inch) platen travel criterion
with the headroom requirement would be a meaningful change to the
standard and may not justify the added complications to the test
procedure.
    Possible conflicts with FMVSS No. 201 ``Occupant protection in
interior impact.'' A number of commenters, including DaimlerChrysler,
Ford, GM, Ferrari and Toyota commented that the proposed headroom
requirement conflicts with the intent of the upper interior
requirements of FMVSS No. 201, Occupant Protection in Interior Impact.
DaimlerChrysler and GM stated that FMVSS No. 201U \20\ countermeasures
have been specifically developed to manage head impact energy and
mitigate injury potential by the dissipation of the impact energy
through deformation of the trim and FMVSS No. 201U countermeasures
themselves. Ford stated that head impact mitigation technologies often
result in the upper interior trim, particularly the roof side rail
trim, being closer to the head of occupants, thereby reducing the
available distance for achieving the SWR requirement prior to headform
contact. It stated that these technologies are designed to reduce the
likelihood of head impact injuries, and that the proposed no-contact
requirement does not account for the potential benefits of these
technologies in a roof deformation situation. GM further stated that
NHTSA's headroom analysis does not establish a correlation between
injuries and head contact with trim components.
---------------------------------------------------------------------------

    \20\ FMVSS 201U, refers to those aspects of FMVSS No. 201
pertaining to the upper interior trim head protection requirements.
---------------------------------------------------------------------------

    Effects on vehicle manufacturing process GM stated that since the
vehicle roof structure is designed very early in the vehicle
development process, it is not possible to reliably predict the
performance or movement of interior trim in a roof crush test. It
stated that structural designs must be completed early in the vehicle
development process to facilitate tooling lead time. According to GM,
the interior trim components (included in the proposed definition of
roof component) are not designed in final form until much later in the
vehicle development process. Therefore, according to that commenter,
the roof structure force deflection characteristics are defined (and
roof crush properties established) before manufacturers can take into
account the package space and deformation requirements of the interior
trim.
    Reduced stringency of the standard Several commenters, including
Public Citizen, IIHS, and LSMM expressed concern that the proposed head
contact criteria could reduce the residual occupant headroom required
after testing, be less stringent for vehicles with existing headroom
greater than 127 mm (5 inches), and thereby allow more than 127 mm (5
inches) of crush. As a result, according to these commenters, the
stringency would be reduced for vehicles with greater than 127 mm (5
inches) of headroom, such as many trucks and Sport Utility Vehicles
(SUVs). We note that Ford commented that most of its light trucks,
multipurpose passenger vehicles and vans (LTVs) have more than 127 mm
(5 inches) of platen travel prior to head contact, while passenger cars
generally have less.
    Alternative headroom requirement approaches A number of commenters
recommended alternative approaches to the proposed headroom
requirement. Biomech Incorporated (Biomech) suggested using a one
gravity static inversion test (using the FMVSS No. 301 fixture) to
learn where the inverted dummy head position would be. It suggested
that deformation in the roof crush test should not be permitted to
reach the measured position of the inverted dummy's head.
    GM, DaimlerChrysler, Toyota, Ferrari and Porsche recommended that
if the agency establishes a headroom reduction criterion, it consider
using a headform position procedure (HPF) that essentially represents a
headform secured to an adjustable vertical support that is rigidly
attached to the floor pan of the tested vehicle at the seat anchorages.
    A number of these commenters also suggested that the agency
consider removing any roof trim components (i.e., all headliner, trim,
deployable countermeasures and grab handles) prior to testing. Further,
these commenters also recommended that

head contact with the roof structure itself be the only assessment
criteria for compliance certification. GM recommended that
manufacturers provide the headform location to NHTSA prior to a
compliance test based upon the nominal design seating positions.
Toyota, by contrast, recommended the agency determine the location for
the 50th percentile male head position with the Head Restraint
Measuring Device (HRMD) \21\ after first determining the H-point using
the SAE J826 procedure, and then position the headform in the vehicle.
---------------------------------------------------------------------------

    \21\ HRMD means the SAE J826 three-dimensional manikin with a
headform attached, representing the head position of a seated 50th
percentile male, with sliding scale at the back of the head for the
purpose of measuring head restraint backset.
---------------------------------------------------------------------------

    DaimlerChrysler recommended verifying compliance by a 200 N (44
pounds) resultant contact force in the upper neck load cell of a 50th
percentile adult male Hybrid III head fixture at the location specified
in the NPRM. DaimlerChrysler recommended that in the event the platen
does not stop quickly enough after the resultant neck force reaches 200
N (44 pounds); the head fixture should be designed to either withdraw
or become compliant by using a force limiting device in order to
prevent any damage to the load cell in the dummy's head. GM also
recommended a similar approach and suggested the agency consider a
range of loads on the headform of 100 N (22 pounds) to 400 N (88
pounds).
    Advocates recommended a maximum intrusion limit of no more than
76.2 mm (3 inches) in order to protect occupants taller than the 50th
percentile male. Public Citizen recommended that NHTSA require that
vehicle roof structures resist more than 76.2 mm (3 inches) of roof
crush, and maintain the minimum amount of headroom proposed in the NPRM
in order to reduce side window breakage and prevent B-pillar
deformation, which it believes can alter seat belt geometry.
    ARCCA, Mr. Slavik and the Advocates also recommended the agency use
a 95th percentile adult male dummy instead of the smaller 50th
percentile male to increase the stringency of the standard and further
limit intrusion.
    Testing with HPF: As noted above, the agency indicated in the SNPRM
that it was considering whether to specify a test using a HPF in the
final rule. We received a number of comments concerning this issue.
    The Alliance reiterated its recommendation that NHTSA maintain the
use of the 127 mm (5 inch) platen travel criterion. That organization
stated that it does not support a ``no head contact'' criterion,
whether it is determined by use of a test dummy or via the use of an
HPF with an associated contact force. The Alliance stated that the
platen travel requirement would yield essentially the same roof
strength and avoid unnecessary test-to-test variability and testing
complexity. That organization stated that if the agency adopts a head
contact criterion in the final rule, it is essential that the head
contact device be a headform on a stand located at a position specified
by the manufacturer and not a crash test dummy or a headform located
based on what it claimed would be very unreliable and unrepeatable
location data estimated from a test dummy or SAE J826 manikin (OSCAR)
location. The Alliance stated that possible use of a 222 N (50 pound)
contact criterion has not been supported by any scientific data.
    In commenting on the SNPRM, GM stated that use of the 127 mm (5
inch) platen travel criterion rather than either a dummy or head
contact fixture is required to prevent unnecessary test variation and
complication while maintaining a comparable level of stringency.
    AIAM did not endorse the HPF approach but suggested that the
fixture might be equipped to measure neck load, to exclude incidental
contact with trim items.
    Public Citizen stated that defining head contact with the HPF by
using force-deflection criteria would result in a significant number of
front seat occupants suffering head and neck injuries.
Agency Response
    After carefully considering the comments, the agency has decided to
adopt the proposed headroom requirement, but with a different test
procedure. Instead of specifying a procedure using a seated Hybrid III
adult male dummy, we are specifying use of a HPF that positions the
headform at the location of a 50th percentile adult male. To help
ensure objectivity and in light of concerns about incidental contact
with trim, head contact is defined as occurring when a 222 N (50 pound)
resultant load is measured by a load cell on the HPF. Finally, to
better ensure safety, we are retaining the current 127 mm (5 inch)
platen travel requirement as well as adopting a headroom requirement.
    Primary Rationale: At the time of the NPRM, the agency estimated
benefits based on post-crash headroom, the only basis for which a
statistical relationship with injury reduction had been established.
After the NPRM, with additional years of data available, a
statistically significant relationship between intrusion and injury for
belted occupants was established.
    NHTSA cited its new headroom and roof intrusion analysis \22\ in
the SNPRM. The agency added two years of NASS-CDS data to each analysis
and found a new, stronger negative correlation between post-crash
headroom and maximum injury severity of head, neck or face from roof
contact. Also, for the first time, the agency was able to find a
statistically significant correlation between vertical roof intrusion
and head, neck, or face injury from roof contact. Based upon this new
analysis, we believe that maintaining headroom, as well as restricting
the amount of intrusion (retaining the platen travel requirement) will
yield benefits in rollover crashes. Therefore, we believe both criteria
should be included in the final rule.
---------------------------------------------------------------------------

    \22\ ibid
---------------------------------------------------------------------------

    Commenters opposing adoption of a headroom requirement raised a
number of concerns, including ones related to the test procedure,
practicability concerns, and whether a headroom requirement would
result in benefits beyond those of the platen travel requirement. The
issues related to the test procedure and practicability concerns are
addressed below.
    As to the issue of additional benefits associated with the headroom
criterion, we note that, based on our testing, in the vast majority of
vehicles it is likely that the limit on platen travel will be
encountered before the one on headroom reduction. For these vehicles,
the new requirement will not pose any significant challenges for
manufacturers, particularly in light of the changes we are making in
the test procedure. However, as we also consider vehicles with less
headroom and potential future vehicles, we believe there is a need to
adopt a headroom reduction requirement to help ensure post-crash
survival space.
    In the NPRM, we raised a concern that for vehicles with greater
than 127 mm (5 inches) of headroom, limiting platen travel to 127 mm (5
inches) may impose a needless burden on these vehicles. However,
manufacturers generally supported retaining the platen travel limit,
suggesting that the requirement is not burdensome. Moreover, as
indicated above, we now have a new analysis showing a statistically
significant relationship between intrusion and injury for belted
occupants.
    Basic Test Procedure for Measuring Head Contact: To help analyze
comments raising repeatability concerns

with the Hybrid III dummy and identifying when head contact occurred,
the agency conducted a series of tests using alternative approaches. In
the first series of tests conducted at NHTSA's Vehicle Research and
Test Center (VRTC), the agency used a head positioning fixture
developed by GM (GM-HPF).\23\ The GM-HPF is a headform secured to an
adjustable vertical support that is rigidly attached to the floor pan
at the seat anchorages. The GM-HPF rigidly holds a headform in the
location of a normally-seated 50th percentile male head and measures
the load on the headform from contact with the interior roof as it is
crushed.
---------------------------------------------------------------------------

    \23\ See Docket Number NHTSA-2005-22143-195
---------------------------------------------------------------------------

    The headform consists of a skull, headskin, and 6-axis upper neck
load cell from a 50th percentile male Hybrid-III dummy (Part 572,
subpart E). This assembly is mounted to the end of a channeled square
tube (upper post). A second, similar tube (lower post) is
perpendicularly mounted to a rectangular aluminum mounting plate. The
upper and lower posts attach to each other and are parallel. The upper
post can slide along the lower post. This provides vertical adjustment
of the headform once the fixture is mounted in the vehicle. The GM-HPF
also includes four metal support straps that attach between the upper/
lower post and the mounting plate, in a pyramid configuration. These
straps provide rigidity to the fixture and are attached after final
positioning of the headform.
    In the testing conducted at VRTC,\24\ the head position of a
normally seated 50th percentile male Hybrid-III dummy was determined by
placing the seat at the mid-track position and using the SAE J826
(OSCAR) device to locate the H-point. A 50th percentile male Hybrid-III
dummy was then positioned per the FMVSS No. 208 seating procedure and
the head location was documented using a 3-dimensional measurement
device. The dummy and seat were then removed. The GM-HPF mounting plate
was attached to the vehicle floor and the headform was then raised
until its vertical position matched that determined from dummy
placement.
---------------------------------------------------------------------------

    \24\ See docket entry NHTSA 2008-0015-003 for the vehicles
tested with the GM-HPF.
---------------------------------------------------------------------------

    After gaining experience with the GM-HPF, the agency developed its
own, simpler HPF approach for evaluating post crash headroom. In doing
so, the agency determined that it is not necessary to use a test device
with the complexity of a headform based on the Hybrid III dummy head,
given the nature of the performance criterion being measured. Earlier
testing had shown that the skin on the Hybrid III dummy's head added a
level of testing complexity that was unnecessary to the goal of
identifying when roof contact occurs at a point in space. Therefore,
the agency developed a simpler HPF using an FMVSS No. 201 headform that
is currently used for testing instrument panels and seat backs. (This
headform is effectively a 16.5 cm (6.5 inch) diameter metallic
hemisphere).
    During roof crush test series conducted at General Testing
Laboratories,\25\ the HPF was developed by mounting the FMVSS No. 201
headform to a cantilevered levering arm which was then attached to a
tri-pod. The levering arm was maintained in position by air pressure
and designed to collapse after a 222 N (50 pound) load was applied. The
purpose of the cantilever design was to allow some downward movement so
as not to damage the device after head contact is reached. The HPF was
positioned in the vehicle at the 50th percentile male head position
using the FMVSS No. 214 seating procedure recently adopted (72 FR
51908) and modified to use the OSCAR with a Head Restraint Measuring
Device attached for repeatable placement. The HPF tri-pod apparatus was
then rigidly secured to the floor of the vehicle. The FMVSS No. 201
headform was mounted on a 3-axis dummy neck load cell, and all loads
and moments were recorded. The roof was then crushed until the
unmodified interior roof made contact with the HPF and the resultant
load, as measured by the load cell, exceeded 222 N (50 pounds). During
our evaluation we defined ``head contact'' as occurring when a 222 N
(50 pound) load is applied to the sphere, in the belief that this load