[Federal Register Volume 70, Number 162 (Tuesday, August 23, 2005)]
[Proposed Rules]
[Pages 49223-49248]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-16661]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
[Docket No. NHTSA-2005-22143]
RIN 2127-AG51
Federal Motor Vehicle Safety Standards; Roof Crush Resistance
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: 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 document proposes to upgrade the agency's safety standard
on roof crush resistance in several ways. First, we are proposing to
extend the application of
[[Page 49224]]
the standard to vehicles with a Gross Vehicle Weight Rating (GVWR) of
4,536 kilograms (10,000 pounds) or less. Second, we are proposing to
increase the applied force to 2.5 times each vehicle's unloaded weight,
and to eliminate an existing limit on the force applied to passenger
cars. Third, we are proposing to replace the current limit on the
amount of roof crush with a new requirement for maintenance of enough
headroom to accommodate a mid-size adult male occupant.
Because the impacts of this rulemaking would affect and be affected
by other aspects of the comprehensive effort to reduce rollover-related
injuries and fatalities, we are also seeking comments on some of those
other aspects.
DATES: You should submit your comments early enough to ensure that
Docket Management receives them not later than November 21, 2005.
ADDRESSES: You may submit comments [identified by DOT Docket Number
NHTSA-2005-22143] by any of the following methods:
Web site: http://dms.dot.gov. Follow the instructions for
submitting comments on the DOT electronic docket site.
Fax: 1-202-493-2251.
Mail: Docket Management Facility; U.S. Department of
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401,
Washington, DC 20590-001.
Hand Delivery: Room PL-401 on the plaza level of the
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 am
and 5 pm, Monday through Friday, except Federal holidays.
Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the online instructions for submitting
comments.
Instructions: All submissions must include the agency name and
docket number or Regulatory Identification Number (RIN) for this
rulemaking. Note that all comments received will be posted without
change to http://dms.dot.gov including any personal information
provided. Please see the Privacy Act heading under Regulatory Notices.
Docket: For access to the docket to read background documents or
comments received, go to http://dms.dot.gov at any time or to Room PL-
401 on the plaza level of the Nassif Building, 400 Seventh Street, SW.,
Washington, DC, between 9 am and 5 pm, Monday through Friday, except
Federal holidays.
FOR FURTHER INFORMATION CONTACT: For technical issues: Ms. Amanda
Prescott, Office of Vehicle Safety Compliance, NVS-224, National
Highway Traffic Safety Administration, 400 7th Street, SW., Washington,
DC 20590. Telephone: (202) 366-5359. Fax: (202) 366-3081. e-mail:
[email protected].
For legal issues: Mr. George Feygin, Attorney Advisor, Office of
the Chief Counsel, NCC-112, National Highway Traffic Safety
Administration, 400 7th Street, SW., Washington, DC 20590. Telephone:
(202) 366-5834. Fax: (202) 366-3820. E-mail:
[email protected].
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Executive Summary and Overview
II. Background
A. Current Performance Requirements
B. Previous Rulemaking, Petitions, and October 2001 Request for
Comments Concerning Performance Requirements
1. Extension of Roof Crush Standard to Light Trucks
2. Plate Positioning Procedure
3. Upgrade of Performance Requirements
C. Consumer Information on Rollover Resistance
D. Development of Comprehensive Plan
III. Overall Rollover Problem and the Agency's Comprehensive
Response
A. Overall Rollover Problem
B. Agency's Comprehensive Response
IV. The Role of Roof Intrusion in the Rollover Problem
A. Rollover Induced Vertical Roof Intrusion
B. Occupant Injuries in Rollover Crashes Resulting in Roof
Intrusion
V. Previous Rollover and Roof Crush Mitigation Research
A. Vehicle Testing
B. Analytical Research
C. Latest Agency Testing and Analysis
1. Vehicle Testing
2. Revised Tie-Down Testing
VI. Summary of Comments in Response to the October 2001 Request for
Comments
VII. Agency Proposal
A. Proposed Application
1. MPVs, Trucks and Buses with a GVWR of 4,536 Kilograms (10,000
pounds) or Less
2. Vehicles Manufactured in Two or More Stages
3. Convertibles
B. Proposed Amendments to the Roof Strength Requirements
1. Increased Force Requirement
2. Headroom Requirement
C. Proposed Amendments to the Test Procedures
1. Retaining the Current Test Procedure
2. Dynamic Testing
3. Revised Tie-Down Procedure
4. Plate Positioning Procedure
VIII. Other Issues
A. Agency Response to Hogan Petition
B. Agency Response to Ford and RVIA Petition
C. Request for Comments on Advanced Restraints
IX. Benefits
X. Costs
XI. Lead Time
XII. Request for Comments
XIII. Rulemaking Analyses and Notices
A. Executive Order 12866 and DOT Regulatory Policies and
Procedures
B. Regulatory Flexibility Act
C. National Environmental Policy Act
D. Executive Order 13132 (Federalism)
E. Unfunded Mandates Act
F. Civil Justice Reform
G. National Technology Transfer and Advancement Act
H. Paperwork Reduction Act
I. Plain Language
J. Privacy Act
XIV. Vehicle Safety Act
XV. Proposed Regulatory Text
I. Executive Summary and Overview
As part of a comprehensive plan for reducing the risk of death and
serious injury from rollover crashes, this notice proposes to upgrade
Federal Motor Vehicle Safety Standard (FMVSS) No. 216, Roof Crush
Resistance. This standard, which seeks to reduce deaths and serious
injuries resulting from crushing of the roof into the occupant
compartment as a result of ground contact during rollover crashes,
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 is forced down onto the roof of a vehicle, simulating contact
with the ground in rollover crashes, the vehicle roof structure must
withstand a force equivalent to 1.5 times the unloaded weight of the
vehicle, without the test plate moving more than 127 mm (5 inches).
Under S5 of the standard, the application of force is limited to 22,240
Newtons (5,000 pounds) for passenger cars.
Recent agency data show that nearly 24,000 occupants are seriously
injured and 10,000 occupants are fatally injured in approximately
273,000 non-convertible light vehicle rollover crashes that occur each
year. In order to identify how many of these occupants might benefit
from this proposal, the agency analyzed real-world injury data in order
to determine the number of occupant injuries that could be attributed
to roof intrusion. The agency examined only front outboard occupants
who were belted, not fully ejected from their vehicles, whose most
severe injury was associated with roof contact, and whose seating
position was located below a roof component that experienced vertical
intrusion as a result of a rollover crash. NHTSA estimates that there
are about 807 seriously and approximately 596 fatally injured occupants
that fit these criteria. The agency believes that some of these
[[Page 49225]]
occupants would benefit from this proposal.
To better address fatalities and injuries occurring in roof-
involved rollover crashes, we are proposing 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 eliminating the 22,240
Newtons (5,000 pounds) force limit for passenger cars. Further, we are
proposing a new direct limit on headroom reduction, which would replace
the current limit of test plate movement. This new limit would prohibit
any roof component from contacting a seated 50th percentile male dummy
under the application of a force equivalent to 2.5 times the unloaded
vehicle weight. For vehicles built in two or more stages, the agency is
proposing an option of certifying to the roof crush requirements of
FMVSS No. 220, ``School bus rollover protection,'' instead of FMVSS No.
216. Finally, in response to several petitions, we reexamined the
current testing procedures and are proposing certain modifications to
the vehicle tie-down procedure and test plate positioning for raised or
altered roof vehicles.
Consistent with the agency's continuing effort to reduce rollover-
related injuries and fatalities, this document requests additional
comments on certain other countermeasures that could further this
initiative. Specifically, we ask for comments related to seat belt
pretensioners that could limit vertical head excursion in a rollover
event.
The agency used two alternative methods to estimate the benefits of
this proposal. Under the first alternative, we estimate that this
proposal would prevent 793 non-fatal injuries and 13 fatalities. Under
the second alternative, we estimate that this proposal would prevent
498 non-fatal injuries and 44 fatalities. The annual equivalent lives
saved are estimated at 39 and 55, respectively.
The estimated average cost in 2003 dollars, per vehicle, of meeting
the proposed requirements would be $10.67 per affected vehicle. Added
weight from design changes is estimated to increase lifetime fuel costs
by $5.33 to $6.69 per vehicle. The cost per year for the vehicle fleet
is estimated to be $88-$95 million. The cost per equivalent life saved
is estimated to range from $2.1 to $3.4 million.
II. Background
A. Current Performance Requirements
FMVSS No. 216 currently applies to passenger cars, multipurpose
passenger vehicles (MPVs), trucks, and buses \1\ with a GVWR of 2,722
kilograms (6,000 pounds) or less. The standard requires that the ``roof
over the front seat area'' \2\ must withstand a force equivalent to 1.5
times the unloaded weight of the vehicle. For passenger cars, this
force is limited to a maximum of 22,240 N (5,000 pounds). Specifically,
the vehicle's roof must prevent the test plate from moving more than
127 mm (5 inches) in the specified test.
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\1\ For simplicity, this notice will refer to MPVs, trucks, and
buses collectively as light trucks.
\2\ The roof over the front seat area means the portion of the
roof, including windshield trim, forward of a transverse plane
passing through a point 162 mm rearward of the seating reference
point of the rearmost front outboard seating position.
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To test compliance, a vehicle is secured on a rigid horizontal
surface, and a steel rectangular plate is angled and positioned on the
roof to simulate vehicle-to-ground contact over the front seat area.
This plate is used to apply the specified force to the roof structure.
Currently, no test device is used to simulate an occupant in the front
seat area.
In order to simulate vehicle-to-ground contact, the plate is tilted
forward at a 5-degree angle, along its longitudinal axis, and rotated
outward at a 25-degree angle, along its lateral axis, so that the
plate's outboard side is lower than its inboard side. The edges of the
test plate are positioned based on fixed points on the vehicle's roof.
For vehicles with conventional roofs, the forward edge of the plate
is positioned 254 mm (10 inches) forward of the forwardmost point on
the roof, including the windshield trim. This same position is required
for vehicles with raised \3\ or altered \4\ roofs, unless the initial
point of contact with the plate is rearward of the front seat area. In
those instances, the plate is moved forward until its rearward edge is
tangent to the rear of the front seat area.
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\3\ ``Raised roof'' means, with respect to a roof, which
includes an area that protrudes above the surrounding exterior roof
structure, that protruding area of the roof.
\4\ ``Altered roof'' means the replacement roof on a motor
vehicle whose original roof has been removed, in part or in total,
and replaced by a roof that is higher than the original roof. The
replacement roof on a motor vehicle whose original roof has been
replaced, in whole or in part, by a roof that consists of glazing
materials, such as those in T-tops and sunroofs, and is located at
the level of the original roof, is not considered to be an altered
roof.
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B. Previous Rulemaking, Petitions, and October 2001 Request for
Comments Concerning Performance Requirements
1. Extension of Roof Crush Standard to Light Trucks
In an effort to reduce deaths and injuries resulting from roof
crush into the passenger compartment area in rollover crashes, the
agency established FMVSS No. 216, ``Roof crush resistance.''
Specifically, the agency sought to address the strength of roof
structures located over the front seat area of passenger cars.
Compliance with the standard was first required on September 1, 1973.
On April 17, 1991, NHTSA published a final rule amending FMVSS No.
216 to extend its application to MPVs, trucks, and buses with a GVWR of
2,722 kilograms (6,000 pounds) or less.\5\ The final rule adopted the
same requirements and test procedures as those applicable to passenger
cars, except for the 22,240 Newton (5,000 pound) limit on the applied
force. Compliance with the final rule was required on September 1,
1994.
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\5\ See 56 FR 15510.
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2. Plate Positioning Procedure
Subsequently, NHTSA published a final rule (1999 final rule)
responding to several petitions for rulemaking seeking to revise the
test plate positioning procedure.\6\ Prior to the 1999 final rule, the
test plate was positioned based on initial point of contact with the
roof. After establishing the initial point of contact, the test plate
was moved forward until its forwardmost edge was positioned 254 mm (10
inches) in front of the initial point of contact. For certain vehicles
with aerodynamically sloped roofs, this procedure resulted in the test
plate being positioned rearward of the roof over the front seat
area.\7\ Consequently, the plate did not apply the force in the
location contemplated by the standard, i.e., over the front occupants.
In some instances, the test plate was positioned such that the edge of
the plate was in contact with the roof, which resulted in excessive and
unrealistic deformation during testing. Similar problems occurred in
testing vehicles with raised or altered roofs.
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\6\ See 64 FR 22567 (April 27, 1999).
\7\ Examples of these vehicles include model year 1999 Ford
Taurus and Dodge Neon.
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The 1999 final rule addressed the difficulty in testing
aerodynamically sloped roofs by specifying that the test plate be
positioned 254 mm (10 inches) forward of the forwardmost point of the
roof (including the windshield trim). This ensured that the leading
edge of
[[Page 49226]]
the plate did not contact the roof and that the test plate applied the
force over the front seat area.
Certain vehicles with raised or altered roofs experienced plate
positioning difficulties similar to those in vehicles with
aerodynamically sloped roofs because the initial contact point on the
roof occurred not over the front seat area, but on the raised rear
portion of the roof. Consequently, the 1999 final rule provided for a
secondary test procedure intended for vehicles with raised or altered
roofs. Under this new test procedure, the test plate is moved forward
until the rearward edge is tangent to the transverse vertical plane
located at the rear of the roof over the front seat area.
On June 11, 1999, the Recreational Vehicle Industry Association
(RVIA) and Ford Motor Company (Ford) submitted petitions for
reconsideration to amend the 1999 final rule.\8\ Petitioners argued
that the secondary plate positioning test procedure produced rear edge
plate loading onto the roof of some raised and altered roof vehicles
that caused excessive deformation uncharacteristic of real-world
rollover crashes. Specifically, petitioners argued that positioning the
test plate such that the rear edge of the plate is at the rearmost
point of the front occupant area resulted in stress concentration,
which produced excessive deformation and even roof penetration.
Petitioners argued that this type of loading is uncommon to real-world
rollovers. Consequently, petitioners asked the agency to reconsider
adopting the secondary plate positioning procedure for raised or
altered roof vehicles.\9\ The agency responds to these petitions for
reconsideration in Section VIII(B) of this document.
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\8\ See Docket Nos. NHTSA-99-5572-3 & NHTSA-99-5572-2,
respectively at: http://dms.dot.gov/search/searchFormSimple.cfm.
\9\ On January 31, 2000, the agency published a partial response
to petitions delaying application of the new secondary plate
positioning testing procedure until October 25, 2000. See 65 FR
4579.
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3. Upgrade of Performance Requirements
On May 6, 1996, the agency received a petition for rulemaking from
Hogan, Smith & Alspaugh, P.C. (Hogan).\10\ Hogan argued that the
current static requirements in FMVSS No. 216 bear no relationship to
real-world rollover crash conditions and therefore should be replaced
with a more realistic test such as the inverted vehicle drop test
defined in the Society of Automotive Engineers Recommended Practice
J996 (SAE J996), ``Inverted Vehicle Drop Test Procedure.'' The
petitioner also requested that NHTSA require ``roll cages'' to be
standard in all cars. NHTSA granted this petition on January 8, 1997,
believing that the inverted drop test had merit for further agency
consideration. The agency addresses the issues raised in this petition
in Section VIII(A) of this document.
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\10\ See Docket No. NHTSA-2005-22143.
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On October 22, 2001, NHTSA published a Request for Comments (RFC)
to assist in an upgrade of FMVSS No. 216 and in addressing issues
raised by the Hogan petition requesting that the agency adopt dynamic
testing.\11\ In the RFC, the agency posed questions related to (1)
current FMVSS No. 216 test requirements and procedures; (2) the
viability of introducing dynamic testing; and (3) ways to limit
headroom reduction. The agency received over 50 comments from the
public. The agency used the information gathered from these responses
in preparing this NPRM. A summary of comments is provided in Section VI
of this document.
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\11\ See 66 FR 53376.
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C. Consumer Information on Rollover Resistance
In 1991, Congress instructed NHTSA to assess rollover occupant
protection as a part of the Intermodal Surface Transportation
Efficiency Act (ISTEA). ISTEA required the agency to initiate
rulemaking to address the injuries and fatalities associated with
rollover crashes. In response to that mandate, NHTSA published an
advance notice of proposed rulemaking (ANPRM) that summarized
statistics and research in rollover crashes, sought answers to several
questions about vehicle stability and rollover crashes, and outlined
possible regulatory and other approaches to reduce rollover
fatalities.\12\ NHTSA also published a report to Congress that detailed
the agency's efforts on rollover occupant protection.\13\
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\12\ See 57 FR 242 (January 3, 1992).
\13\ See Docket Number NHTSA 1999-5572-35.
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In 1994, the agency proposed a new consumer information regulation
to require that passenger cars and light multipurpose passenger
vehicles and trucks be labeled with information about their resistance
to rollover.\14\ However, after issuing the notice of proposed
rulemaking, Congress directed NHTSA not to issue a final rule on
vehicle rollover labeling until the agency had reviewed a study by the
National Academy of Sciences (NAS) on how to most effectively
communicate motor vehicle safety information to consumers.\15\
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\14\ See 59 FR 33254 (June 28, 1994).
\15\ See 65 FR 34998 at 35001 (June 1, 2000).
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After the agency reviewed the NAS study, we issued a Request for
Comments proposing to use Static Stability Factor to indicate rollover
risk in single-vehicle crashes, as a part of NHTSA's New Car Assessment
Program (NCAP). That program provides consumers with vehicle safety
information, including crash test results, to aid consumers in their
vehicle purchase decisions.\16\ In 2001, the agency issued a final
decision to use the Static Stability Factor to indicate rollover risk
in single-vehicle crashes and to incorporate the new rating into
NCAP.\17\
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\16\ See 65 FR 34998 (June 1, 2000).
\17\ See 66 FR 3388 (January 12, 2001).
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Section 12 of the Transportation Recall, Enhancement,
Accountability and Documentation (TREAD) Act of November 2000 mandated
that NHTSA develop a dynamic rollover resistance test for the purposes
of aiding consumer information. On October 14, 2003, NHTSA modified the
New Car Assessment Program to include dynamic rollover tests.\18\
NHTSA's rollover resistance rating information is available at http://www.nhtsa.dot.gov/ncap/.
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\18\ See 68 FR 59250.
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D. Development of Comprehensive Plan
In 2002, the agency formed an Integrated Project Team (IPT) to
examine the rollover problem and make recommendations on how to reduce
rollovers and improve safety when rollovers nevertheless occur. In June
2003, based on the work of the team, the agency published a report
entitled, ``Initiatives to Address the Mitigation of Vehicle
Rollover.'' \19\ The report recommended improving vehicle stability,
ejection mitigation, roof crush resistance, as well as road improvement
and behavioral strategies aimed at consumer education.
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\19\ See Docket Number NHTSA 2003-14622-1.
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III. Overall Rollover Problem and the Agency's Comprehensive Response
This proposal to upgrade our safety standard on roof crush
resistance is one part of a comprehensive agency plan for reducing the
serious risk of rollover crashes and the risk of death and serious
injury when rollover crashes do occur.
A. Overall Rollover Problem
Rollovers are especially lethal crashes. While rollovers comprise
just 3% of all light passenger vehicle crashes, they account for almost
one-
[[Page 49227]]
third of all occupant fatalities in light vehicles, and more than 60
percent of occupant deaths in the SUV segment of the light vehicle
population.\20\
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\20\ See Automotive News World Congress, ``Meeting the Safety
Challenge'' Jeffrey W. Runge, M.D., Administrator, NHTSA, January
14, 2003, page 3, 4; (http://www.nhtsa.dot.gov/nhtsa/announce/speeches/030114Runge/AutomotiveNewsFinal.pdf); see also The
Honorable Jeffrey W. Runge, M.D., Administrator, NHTSA, before the
Committee on Commerce, Science, and Transportation. U.S. Senate,
February 26, 2003; (http://www.nhtsa.dot.gov/nhtsa/announce/testimony/SUVtestimony02-26-03.htm); see also IPT Rollover Report at
http://www-nrd.nhtsa.dot.gov/vrtc/ca/capubs/IPTRolloverMitigationReport/ (Page 7).
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Rollover fatalities are strongly associated with the following
factors: A single vehicle crash (83 percent), a rural crash location
(60 percent), a high-speed (55 mph or higher) road (72 percent),
nighttime (66 percent), off-road tripping/tipping mechanism (60
percent), young (under 30 years old) driver (46 percent), male driver
(73 percent), alcohol-related (40 percent), and/or speed-related (40
percent).\21\
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\21\ See id. at 8.
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The agency previously estimated that approximately 64 percent of
about 10,000 occupants fatally injured in rollovers each year are
injured when they are either partially or completely ejected during the
rollover. Approximately 53 percent of the fatally injured are
completely ejected, and 72 percent are unbelted.\22\ Most of the
fatally injured are ejected through side windows \23\ or side
doors.\24\ Those who are not ejected, including belted occupants, are
fatally injured as a result of impact with the vehicle interior.
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\22\ See IPT Rollover Report at http://www-nrd.nhtsa.dot.gov/vrtc/ca/capubs/IPTRolloverMitigationReport/ (Page 5).
\23\ Status of NHTSA's Ejection Mitigation Research, J. Stephen
Duffy, Transportation Research Center, Inc., SAE Government/Industry
Meeting, May 10, 2004, slide 2, http://www-nrd.nhtsa.dot.gov/pdf/nrd-01/SAE/SAE2004/EjectMitigate_Duffy.pdf.
\24\ See IPT Rollover Report at http://www-nrd.nhtsa.dot.gov/vrtc/ca/capubs/IPTRolloverMitigationReport/ (Page 12).
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Approximately 273,000 non-convertible light vehicles were towed
after a police-reported rollover crash each year. Of these 273,000
light vehicle rollover crashes, 223,000 were single-vehicle rollover
crashes. Previous agency data indicate that in ninety-five (95) percent
of single-vehicle rollover crashes, the vehicles were tripped, either
by on-road mechanisms such as potholes and wheel rims digging into the
pavement or by off-road mechanisms such as curbs, soft soil, and
guardrails.\25\ Eighty-three (83) percent of single-vehicle rollover
crashes occurred after the vehicle left the roadway.\26\ Five (5)
percent of single vehicle rollovers were untripped rollovers. They
occurred as a result of tire and/or road interface friction.
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\25\ See id. at 6. Tripped rollovers result from a vehicle's
sideways motion, as opposed to its forward motion. When sideways
motion is suddenly interrupted, for example, when a vehicle is
sliding sideways and its tires on one side encounter something that
stops them from sliding, the vehicle may roll over. Whether or not
the vehicle rolls over in that situation depends on its speed in a
sideways direction (lateral velocity). By measuring certain vehicle
dimensions, it is possible to calculate each make/model's
theoretical minimum lateral sliding velocity for this type of
rollover to occur.
\26\ See id.
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NHTSA estimates that 23,793 serious injuries \27\ and 9,942
fatalities occur in 272,925 non-convertible light duty vehicle \28\
rollover crashes each year. In evaluating the risks of fatalities and
serious injuries associated with rollover crashes, NHTSA has concluded
that rollover crashes involving light duty vehicles present a higher
risk of injury compared to frontal, side, and rear impacts.\29\
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\27\ Abbreviated Injury Scale (AIS) 3 to 5.
\28\ We refer to vehicles with GVWR less than or equal to 4,536
kilograms (10,000 pounds) as light duty vehicles.
\29\ Injury risk is measured by the ratio of fatal and serious
injuries to the number of occupants involved in towaway crashes.
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In arriving at our conclusions, NHTSA used (1) the Fatality
Analysis Reporting System (FARS) from 1997 through 2002 to determine
the annual average number of fatalities in non-convertible light duty
vehicles, and (2) the National Automotive Sampling System
Crashworthiness Data System (NASS-CDS) from 1997 through 2002 to
determine the annual average number of seriously injured survivors of
towaway crashes. These estimates were combined to produce the results
in Table 1.\30\
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\30\ NASS-CDS estimates have been adjusted to account for cases
with unknown or missing data.
Table 1.--Risk of Fatality and Serious Injury to Occupants of Non-Convertible Light Vehicles Involved in a
Towaway Crashes by Crash Type
[NASS-CDS & FARS 1997-2002]
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Percent of
Percent of Fatal and occupants
Crash type Total Fatalities occupants serious fatally or
occupants fatally injuries seriously
injured injured
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Rollover........................ 467,120 9,942 2.1 33,735 7.2
Frontal Impact.................. 2,786,378 12,480 0.4 58,031 2.1
Side Impact..................... 1,218,068 7,932 0.6 29,964 2.5
Rear Impact..................... 414,711 1,029 0.2 2,338 0.6
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The estimates in Table 1 show that compared to other crash events,
such as frontal, side, and rear impacts, rollover crashes present a
greater risk of fatal or serious injury. However, the higher injury
risks in rollover crashes may largely result from greater likelihood of
full ejection from the vehicle, compared to other crash modes. Further,
younger drivers, who may be more likely to become involved in
rollovers, might also be less likely to use a safety restraint.\31\
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\31\ For younger drivers and rollovers, see William Deutermann,
``Characteristics of Fatal Rollover Crashes,'' DOT HS 809 438, April
2002 (http://www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/Rpts/2002/809-438.pdf). For younger occupants and seat belt use, see Donna
Glassbrenner, ``Safety Belt Use in 2003,'' DOT HS 809 729, May 2004
(http://www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/Rpts/2004/809729.pdf).
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Accordingly, to refine further the injury risk estimates more
relevant to this proposal, we examined the rollover injury risks
experienced by belted vehicle occupants, and vehicle occupants that had
not been fully ejected. Although the injury risk estimates for belted
occupants are lower, they remain higher for rollover crashes than for
other crash modes.
[[Page 49228]]
Table 2.--Risks of Fatality and Serious Injury to Not Fully Ejected Occupants and Belted Occupants of Non-Convertible Light Vehicles Involved in a
Towaway Crash by Crash Type
[NASS-CDS and FARS 1997 to 2002]
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Percent of not fully Percent of belted
Percent of not fully ejected occupants Percent of belted occupants fatally or
Crash type ejected occupants fatally or seriously occupants fatally seriously injured
fatally injured injured (regardless of injured (regardless of (regardless of ejection
(regardless of belt use) belt use) ejection status) status)
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Rollover........................................ 1.1 4.3 0.7 3.5
Frontal Impact.................................. 0.4 2.0 0.3 1.4
Side Impact..................................... 0.6 2.3 0.5 1.9
Rear Impact..................................... 0.2 0.5 0.1 0.3
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B. Agency's Comprehensive Response
The agency has published a comprehensive plan to reduce rollover
related fatalities and injuries. It is clear that the most effective
way to reduce deaths and injuries in rollover crashes is to prevent the
rollover crash from occurring. Countermeasures to help reduce rollover
occurrence include:
Providing consumers with information to make informed
decisions when purchasing vehicles. The agency's New Car Assessment
Program provides information on rollover risk predictions for light
vehicles. Starting with the 2004 model year, NHTSA is making risk
predictions that are based both on the vehicle's static stability
factor and its performance in the agency's dynamic (fishhook) test.
Continued research and development of advanced vehicle
technologies, such as electronic control systems, road departure
warnings and rollover sensors. For example, preliminary data
indicates that electronic stability control systems appear
effectively to reduce the occurrence of single-vehicle crashes.\32\
Vehicle manufacturers continue to develop and deploy such
technologies.
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\32\ Dang, Jennifer, ``Preliminary Results Analyzing the
Effectiveness of Electronic Stability Control (ESC) Systems,'' DOT
HS 809 790, September 2004. Several recent studies in Japan and
Europe also indicate that ESC systems reduce single vehicle crashes.
However, the samples of vehicles equipped with these systems were
small. See also, C.M. Farmer ``Effect of electronic stability
control,'' Traffic Injury Prevention 5:4 (317-25).
---------------------------------------------------------------------------
Continued focus on the enforcement of laws discouraging
impaired driving and compliance with speed limits and other safe
driving behavior. As noted above, rollovers often involve speed
(40%) and/or alcohol (40%), and tend to be associated with younger
(46%), male (73%) drivers.
Countermeasures are also needed to mitigate injuries and fatalities
when rollovers do occur. Such countermeasures include:
Continued focus on ejection mitigation measures, such
as side curtain airbags and rollover sensors. Such technologies are
increasingly made available to the vehicle buying public. The agency
will continue collaborative research efforts and, if appropriate,
will establish regulations to ensure their continued deployment in
the vehicle fleet.
Enhancing other aspects of occupant protection, such as
door retention (FMVSS 206), occupant restraints (FMVSS 208) and roof
crush (FMVSS 216). For example, advanced safety belt systems
incorporating pretensioners may help keep occupants from impacting
the roof structure during a rollover.
The continued enactment of primary safety belt laws and
a continued focus on the enforcement of such laws. Safety belt use
is a critical feature of reducing rollover-related fatalities and
injuries. Approximately 75 percent of the people killed or injured
in single-vehicle rollovers are unbelted. Twenty-nine states have
yet to enact primary belt laws. Of those, twenty-one states report
safety belt use below the national average of 80 percent.\33\
\33\ See http://www.nhtsa.dot.gov/people/injury/airbags/809713.pdf.
---------------------------------------------------------------------------
All of these countermeasures must work together to help create a
driving environment in which rollovers can be avoided and rollover-
related fatalities and injuries minimized. States legislatures, the
enforcement community (including police officers, prosecutors and
judges), vehicle makers and their suppliers and the driving public all
play critical parts in eliminating the 10,000 rollover-related
fatalities suffered each year. Government also plays a role in ensuring
that safety requirements are mandated when the benefits of doing so are
established. This proposal to upgrade our roof crush standard is only
one such effort by the agency to address the rollover hazard.
IV. The Role of Roof Intrusion in the Rollover Problem
A. Rollover Induced Vertical Roof Intrusion
The agency has examined data on vehicle rollovers resulting in roof
damage.\34\ This information was derived from NASS-CDS (1997 to 2002).
Vertical roof intrusion is recorded in NASS-CDS when it exceeds 2 cm
(0.8 inches).
---------------------------------------------------------------------------
\34\ Roof damage is measured by the maximum degree of vertical
intrusion into the vehicle by a roof component (A-pillar, B-pillar,
roof, roof side rail, windshield header, and backlight header).
---------------------------------------------------------------------------
Using the NASS-CDS data from 1997 to 2002, we conclude that out of
the total of 272,925 light duty vehicle rollovers in towaway crashes,
220,452 rolled more than one-quarter turn.\35\ The 52,473 vehicles that
experienced only a one-quarter turn were excluded from the analysis
because one-quarter turn rollovers usually do not result in vertical
roof intrusion since they do not experience roof-to-ground contact. We
found that out of the 220,452 vehicles that rolled more than one-
quarter turn, 175,253 experienced vertical intrusion of some roof
component. We estimate that in 82 percent (142,954) of these cases, the
most severe roof intrusion occurred over the front seat positions.
Approximately 92 percent of the fatally or seriously injured belted
occupants who were not fully ejected were in front seats.
---------------------------------------------------------------------------
\35\ A quarter turn occurs when the vehicle tips over from the
upright position onto either of its sides.
---------------------------------------------------------------------------
In addition, NHTSA examined how vertical roof intrusion relates to
a vehicle's body type and GVWR. We compared passenger cars, light
trucks currently subject to the standard, and light trucks with a GVWR
greater than 2,722 kilograms (6,000 pounds) but less than or equal to
4,536 kilograms (10,000 pounds). The estimates in Table 3 show that
light trucks not subject to the current standard experienced patterns
of roof intrusion which were slightly greater than vehicles already
subject to the requirements of FMVSS No. 216. Further, the heavier
vehicles above 2,722 kilograms (6,000 pounds) experienced a greater
maximum vertical roof intrusion.
[[Page 49229]]
Table 3.--Percent of Vehicles Involved in Rollover Crashes (More Than One Quarter-Turn) by Degree of Vertical
Roof Intrusion
[1997-2002 NASS-CDS and 2002 Polk National Vehicle Population Profile (NVPP)]
----------------------------------------------------------------------------------------------------------------
Light trucks with GVWR
Maximum vertical roof intrusion Passenger cars Light trucks subject to > 2,722 and <= 4,536 Kg
(percent) FMVSS No. 216 (percent) (percent)
----------------------------------------------------------------------------------------------------------------
No Intrusion......................... 23,071 (23) 17,805 (19) 14,322 (17)
3 to 7 cm............................ 22,219 (22) 19,264 (20) 1,499 (6)
8 to 14 cm........................... 22,285 (22) 12,354 (13) 5,122 (21)
15 to 29 cm.......................... 25,260 (25) 31,184 (33) 10,487 (42)
30 to 45 cm.......................... 4,810 (5) 12,225 (13) 2,107 (8)
46 cm or more........................ 2,334 (2) 2,695 (3) 1,253 (5)
--------------------------
Total............................ 100,075 (100) 95,586 (100) 24,791 (100)
Average Amount of Intrusion...... 82.4 mm 111.3 mm 150.5 mm
==========================
Total Number of Vehicles......... 220,452
----------------------------------------------------------------------------------------------------------------
B. Occupant Injuries in Rollover Crashes Resulting in Roof Intrusion
In addition to examining the risk of injuries associated with
rollover events, and the prevalence of roof intrusions resulting from
rollover, the agency examined actual occupant injuries and fatalities
resulting from roof intrusions that occurred after the vehicle rolled
more than one-quarter turn or end-over-end. Some occupants sustaining
these injuries could potentially benefit from upgrading the roof crush
resistance requirements.
Again, the agency limited this injury analysis to belted occupants
who were not fully ejected from their vehicles. In order to determine
the number of occupant injuries that could be attributed to roof
intrusion, the injury data were further limited to only front outboard
occupants.\36\ Further, NHTSA excluded rollover crashes producing roof
intrusion as a result of a collision with a fixed object such as a tree
or a pole. Using NASS-CDS (1997--2002) data, NHTSA estimates that 4
percent of vehicles involved in rollovers collided with fixed objects
in a way that caused roof damage. The agency excluded these vehicles in
assessing potential benefits of this proposal because we found that
roof damage observed from fixed object collisions was often
catastrophic in nature and exhibited different deformation patterns
than roof-to-ground impacts due to the localization of the force. The
agency believes that this proposal is not likely to have appreciable
benefits for these types of collisions. Finally, the occupant MAIS
injury must have resulted from contact with a roof component.\37\
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\36\ We excluded rear outboard belted occupants because FMVSS
No. 216 requires that the roof over the front seat area withstand
the applied force. As previously stated, in 82 percent of relevant
crashes, the most severe roof intrusion occurred over the front seat
position. Further, we lacked the headroom data necessary to estimate
potential benefits to rear seat occupants.
\37\ MAIS injury is the most severe (maximum AIS) injury for the
occupant.
---------------------------------------------------------------------------
Our refined analysis shows that annually, there are an estimated
807 seriously and 596 fatally injured belted occupants (1,403 total)
involved in rollovers resulting in roof intrusion that suffered MAIS
injury from roof contact. The rollover injury distributions according
to belt use, MAIS source, and roof intrusion is illustrated in Figure
1. Thus, although the number of serious and fatal injuries resulting
from rollovers is very high, the number of occupants who could
potentially benefit from upgraded roof crush resistance requirements is
considerably more limited. However, despite the relatively small number
of rollover occupants who may directly benefit from this proposal, the
agency believes that roof crush resistance is an integral part of the
occupant protection system, necessary to ensure benefits can be
obtained from designing other rollover mitigation tools (such as
padding and the restraint system) to provide better protection against
injuries resulting from rollover. We note that seriously and fatally
injured occupants who had a non-MAIS roof contact injury may also
derive some benefit from decreased roof intrusion.
BILLING CODE 4910-59-U
[[Page 49230]]
[GRAPHIC] [TIFF OMITTED] TP23AU05.022
BILLING CODE 4910-59-C
V. Previous Rollover and Roof Crush Mitigation Research
Prior to issuing the October 2001 RFC, NHTSA conducted a research
program to examine potential methods for improving the roof crush
resistance performance requirements. This program included vehicle
testing and analytical research.
A. Vehicle Testing
The agency vehicle testing program has consisted of: (1) Full
vehicle dynamic rollover testing; (2) inverted vehicle drop testing;
and (3) comparing inverted drop testing to a modified FMVSS No. 216
test.
The agency conducted over 25 full-scale dynamic rollover tests to
evaluate roof integrity and failure modes in rollover crashes. These
tests were expected to produce severe roof intrusion in order to help
the agency investigate possible roof crush countermeasures and compare
roof strengths. NHTSA designed a rollover test cart that was similar to
the dolly rollover cart (as defined in FMVSS No. 208, ``Occupant crash
protection''), and vertically elevated it 1.2 meters.
[[Page 49231]]
Pneumatic cylinders were used to initiate the vehicle's angular
momentum. However, these test conditions proved so severe it was
difficult to identify which vehicles had better performing roof
structures and which had the worse performing roof structures.\38\ Due
to severity of roof crush and demonstrated lack of repeatability of
results, this test procedure did not provide a reliable performance
measure for roof crush resistance. Based on these tests, the agency
determined that the development of an improved roof crush standard
based on dynamic rollover testing was not feasible, so we proceeded to
investigate alternatives.
---------------------------------------------------------------------------
\38\ Several identical vehicles with different levels of roof
reinforcement were subjected to the test. Accordingly, we expected
to observe some variability in roof performance.
---------------------------------------------------------------------------
NHTSA then evaluated the inverted drop test procedure based on the
SAE J996 procedure. Previous research had suggested that the inverted
drop test produced deformation patterns similar to those observed in
real-world crashes.\39\ NHTSA conducted a series of inverted drop tests
and concluded that they were not necessarily better than quasi-static
tests in representing vehicle-to-ground interaction occurring during
rollover. Further, the inverted drop test procedure was significantly
more difficult to conduct because it required a cumbersome procedure
for suspending and inverting the vehicle. The agency concluded that the
quasi-static test procedure is simpler and produces more repeatable
results.
---------------------------------------------------------------------------
\39\ Michael J. Leigh and Donald T. Willke, ``Upgraded Rollover
Roof Crush Protection: Rollover Test and NASS Case Analysis,''
Docket NHTSA-1996-1742-18, June 1992; and Glen C. Rains and Mike Van
Voorhis, ``Quasi Static and Dynamic Roof Crush Testing,'' DOT HS
808-873, 1998.
---------------------------------------------------------------------------
Further, the agency found that both the inverted drop and quasi-
static tests produced loading and crush patterns comparable to those of
the dynamic rollover test.\40\ Although the roof crush loading sequence
in real-world crashes differs from that of the quasi-static procedure,
we determined that the roof crush patterns observed in quasi-static
tests provide a good representation of the real-world roof
deformations. This finding, coupled with the better consistency and
repeatability of the quasi-static procedure, led the agency to conclude
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.
---------------------------------------------------------------------------
\40\ ``Rollover Roof Crush Studies,'' Contract DTNH22-92-D-
07323, 1993.
---------------------------------------------------------------------------
B. Analytical Research
In 1994, NHTSA conducted an analytical study to explore the
relationship between roof intrusion and the severity of occupant
injury. To determine the extent of the correlation between roof
intrusion and occupant injury, the agency conducted a comparative study
using NASS-CDS.\41\
---------------------------------------------------------------------------
\41\ Kanianthra, Joseph and Rains, Glen, ``Determination of the
Significance of Roof Crush on Head and Neck Injury to Passenger
Vehicle Occupants in Rollover Crashes,'' SAE Paper 950655, Society
of Automotive Engineers, Warrendale, PA, 1994.
---------------------------------------------------------------------------
The study evaluated two sets of belted occupants involved in
rollover events to determine if headroom reduction was related to the
risk of head injury in rollover crashes. One set of occupants had
received head injuries from roof contact, the second set of occupants
had not.
We observed the following: (1) Headroom reduction (pre-crash versus
post-crash) of more than 70 percent substantially increased the risk of
head injury from roof contact; (2) as the severity of the injury
increased, the percentage of cases with no remaining headroom
increased; (3) when the intrusion exceeded the original headroom, the
percentage of injured occupants was 1.8 times the percentage of
uninjured occupants; and (4) the average percent of headroom reduction
for injured occupants was more than twice that of uninjured occupants.
In sum, the agency believes that there is a relationship between the
amount of roof intrusion and the risk of injury to belted occupants in
rollover events.
C. Latest Agency Testing and Analysis
1. Vehicle Testing
Recently, the agency conducted roof crush tests to ascertain roof
strength of more recent model year (MY) vehicles.
First, the agency conducted testing on ten vehicles equipped with
string potentiometers to measure the relationship between external
plate movement and available occupant headroom.\42\ All ten vehicles
withstood an applied force of 1.5 times the unloaded vehicle weight
before the occupant headroom was exhausted. Six out of ten vehicles
attained a peak force greater than 2.5 times the unloaded vehicle
weight before the occupant headroom was exhausted. The detailed summary
and analysis of testing and simulation research is contained in the
document entitled ``Roof Crush Research: Load Plate Angle Determination
and Initial Fleet Evaluation.'' \43\
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\42\ 1st group of vehicles: MY2002 Dodge Ram 1500, MY2002 Toyota
Camry, MY2002 Ford Mustang, MY2002 Honda CRV, MY2002 Ford Explorer,
MY2001 Ford Crown Victoria, MY2001 Chevy Tahoe, MY1999 Ford E-150,
MY1998 Chevy S10 Pickup, and MY1997 Dodge Grand Caravan.
\43\ See Docket Number NHTSA-2005-22143.
---------------------------------------------------------------------------
Subsequently, NHTSA conducted further testing on another set of ten
vehicles with a seated 50th percentile Hybrid III dummy.\44\ All ten
vehicles withstood an applied force of 1.5 times the unloaded vehicle
weight before the occupant headroom was exhausted.\45\ Seven out of ten
vehicles exceeded an applied force of 2.5 times the unloaded vehicle
weight before the occupant headroom was exhausted. One vehicle, a
Subaru Forester, withstood an applied force of 4.0 times the unloaded
vehicle weight before the occupant headroom was exhausted.
---------------------------------------------------------------------------
\44\ 2nd group of vehicles: MY2003 Ford Focus, MY2003 Chevy
Cavalier, MY2003 Subaru Forester, MY2002 Toyota Tacoma, MY2001 Ford
Taurus, MY2003 Chevy Impala, MY2002 Nissan Xterra, MY2003 Ford F-
150, MY2003 Ford Expedition, and MY2003 Chevy Express 15-passenger
van.
\45\ See Docket Number NHTSA-2005-22143.
---------------------------------------------------------------------------
The agency also tested 10 vehicles as a part of NHTSA's compliance
program.\46\ These vehicles were tested in a manner similar to the 20
vehicles described above. However, these vehicles were only crushed to
approximately 127 mm (5 inches) of plate displacement. The data
gathered from these tests were useful in evaluating the roof crush
performance of the fleet under the current requirements, which is
discussed in greater detail in other sections of this notice.\47\
---------------------------------------------------------------------------
\46\ Compliance group of vehicles: MY2003 Mini Cooper, MY2003
Mazda 6, MY2003 Kia Sorento, MY2003 Chevrolet Trailblazer, MY2003
Ford Windstar, MY2004 Honda Element, MY2004 Chrysler Pacifica,
MY2004 Land Rover Freelander, MY2004 Nissan Quest, and MY2004
Lincoln LS.
\47\ See Docket Number NHTSA-2005-22143.
---------------------------------------------------------------------------
2. Revised Tie-Down Testing
As previously discussed, in 1999, the agency issued a final rule
revising the test plate positioning procedures.\48\ In response to the
NPRM which preceded the 1999 final rule, Ford commented that different
laboratories employ various methods to secure the vehicle for FMVSS No.
216 testing. Ford stated that the initial point of contact of the test
plate varied between laboratories, which resulted in different roof
crush resistance. Ford attributed the variation in initial contact
point to the variation in tie-down methodologies.\49\ In response to
the Ford comment, the agency indicated it would address the variability
in tie-down procedures separately.\50\
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\48\ See 64 FR 22567 (April 27, 1999).
\49\ See Docket 94-097-N02-010.
\50\ See 64 FR 22567 at 22576 (April 27, 1999).
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[[Page 49232]]
The tie-down procedure was evaluated as part of the vehicle testing
discussed in Section V(C)(1). While some of the vehicles used for
testing were previously converted to sled bucks as a method to restrain
vehicle motion, the agency does not consider converting vehicles into
sled bucks to be a viable tie-down procedure. Two different methods of
securing vehicles were explored. The first method secured the vehicle
using rigidly attached vertical supports and chains. The second method
used only rigidly attached vertical supports.
Based on the test results, the agency believes that both methods
sufficiently restrain vehicle motion. The agency is proposing to adopt
the second tie-down method using only rigidly attached vertical
supports. Eliminating the use of chains prevents any pre-test stress
resulting from tightening of chains. The agency believes that this
method may result in a more consistent location of the initial contact
point of the test plate. The details on the tie-down procedure testing,
including photographs and relevant data, please see the docket.
VI. Summary of Comments in Response to the October 2001 Request for
Comments
NHTSA received over fifty comments in response to the October 2001
RFC. The comments were submitted by vehicle manufacturers, trade
associations, consumer advocacy groups, and individuals. Specific
comments are addressed in Section VII of this document. Below is a
summary of comments in response to the October 2001 RFC.
The agency received several comments in favor of retaining the
current FMVSS No. 216 requirements and rejecting a dynamic testing
alternative. First, the Alliance of Automobile Manufacturers
(Alliance), DaimlerChrysler (DC), General Motors (GM), and Biomech,
Inc. (Biomech), suggested that there are not any data to suggest that
stronger roofs would reduce severity of injuries in rollover crashes.
Second, Nissan North America, Inc. (Nissan) and Ford suggested that the
current test procedure is the most appropriate one from the standpoint
of repeatability of test conditions and results.
By contrast, NHTSA received several comments opposing the current
quasi-static test procedure. Advocates for Highway Safety (Advocates)
and Public Citizen stated that the current test procedure does not
accurately measure vehicle roof strength and impact response in real-
world rollover crashes. Therefore, the commenters suggested that the
agency adopt a fully dynamic rollover test procedure.
The Alliance, GM, DC and Biomech stated that there are not any data
to support extending application of FMVSS No. 216 to heavier vehicles,
which, they believe, have significantly different rollover
characteristics. By contrast, Consumers Union (CU), Public Citizen and
several individual commenters supported extending application of the
standard to vehicles with a GVWR of 4,536 kilograms (10,000 pounds)
because of the widespread use of heavier sport utility vehicles for
family transportation. These commenters also expressed their concerns
about the rollover propensity of passenger vans.
CU, Public Citizen, and Safety Analysis and Forensic Engineering
(SAFE) suggested that a modified load plate size and position would
better replicate the typical location and concentration of forces in a
rollover event. However, DC and Biomech stated that further changes to
the current load plate size and position would not appreciably reduce
injuries and might lead to unintended compliance and enforcement
problems.
Center for Injury Research recommended that NHTSA include a
sequential test of both sides of the vehicle roof at a roll angle of
50-degrees since the existing FMVSS No. 216 ensures reasonable strength
only on the near side of the roof.
With regard to the force application requirement, Ford and Nissan
stated that the current level of 1.5 times the unloaded vehicle weight
is a sufficient test requirement. However, Public Citizen, Carl Nash,
and Hans Hauschild recommended an increased load and application rate
to replicate the dynamic forces occurring in a rollover event.
Public Citizen, CU and several individual commenters suggested that
FMVSS No. 216 testing should be conducted without the windshield and/or
side glazing because glazing materials often break during the first
quarter turn and provide virtually no support to the roof structure in
subsequent turns.
With respect to a direct headroom reduction limit, Ford, Nissan,
GM, DC and Biomech stated that there is not any indication that
limiting headroom reduction can offer quantifiable benefits for either
belted or unbelted occupants. Specialty Equipment Marketers Association
(SEMA) expressed concern that any proposed headroom regulation would
create a substantial problem for aftermarket manufacturers of sunroofs,
moon roofs and other roof-mounted accessories. Public Citizen, Nash and
other individual commenters suggested that a minimum headroom clearance
requirement should be established because real-world data indicate that
roof crush is directly related to head and neck injuries.
Finally, NHTSA received several comments suggesting that the agency
adopt new requirements to minimize occupant excursion in rollover
crashes and require vehicles to have rollover sensors. Additionally, we
received comments from DC, Biomech, and Ford suggesting that the agency
develop a biofidelic rollover test dummy or at least modify the Hybrid
III.
VII. Agency Proposal
Based on available information, including long-term and more recent
agency research, the assessment of crash and injury statistics, and
evaluation of comments in response to the October 2001 RFC, the agency
has tentatively concluded that FMVSS No. 216 should be upgraded in
order to mitigate serious and fatal injuries resulting from rollover
crashes. Specifically, NHTSA is proposing to:
Extend the application of the standard to MPVs, trucks,
and buses with a GVWR greater than 2,722 kilograms (6,000 pounds), but
not greater than 4,536 kilograms (10,000 pounds).
Allow 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.
Clarify the definition and scope of exclusion for
convertibles.
Require that vehicles subject to the standard withstand
the force of 2.5 times their unloaded vehicle weight.
Eliminate the 22,240 Newton maximum force limit for
passenger cars.
Replace the current plate movement limit with a new direct
limit on headroom reduction, which would prohibit any roof component or
the test plate from contacting the 50th percentile male Hybrid III
dummy seated in either front outboard designated seating position.
Revise the vehicle tie-down procedure to minimize
variability in testing.
Revise the test device positioning to minimize variability
in testing.
A. Proposed Application
1. MPVs, Trucks and Buses with a GVWR of 4,536 Kilograms (10,000
pounds) or Less
Currently, FMVSS No. 216 applies to passenger cars and to MPVs,
trucks and buses with a GVWR of 2,722 kilograms (6,000 pounds) or less.
However, it does
[[Page 49233]]
not apply to school buses, convertibles, and vehicles that conform to
the rollover test requirements in S5.3 of FMVSS No. 208.
As discussed in Section II(B), the agency amended FMVSS No. 216 on
April 17, 1991 by extending application of the standard to include
MPVs, trucks, and buses with a GVWR of 2,722 kilograms (6,000 pounds)
or less. The agency sought to ensure that those vehicles offered a
level of roof crush protection comparable to that offered by passenger
cars.
Prior to the 1991 final rule, NHTSA proposed to extend the
application of the standard up to the GVWR of 4,536 kilograms (10,000
pounds) or less. However, because of concerns regarding the feasibility
of this proposal, the agency adopted a more limited extension and
indicated it would investigate this issue further before conducting
further rulemaking.\51\
---------------------------------------------------------------------------
\51\ See 56 FR 15510 (April 17, 1991).
---------------------------------------------------------------------------
As previously discussed in Section IV(A), recent data indicate that
a significant number of serious and fatal injuries occur during
rollovers of light trucks with a GVWR between 2,722 kilograms (6,000
pounds) and 4,536 kilograms (10,000 pounds). Based on these injury data
and the responses to the October 2001 RFC, the agency is once again
proposing to extend the application of the standard to include light
trucks with a GVWR up to 4,536 kilograms (10,000 pounds).
In comments on the October 2001 RFC, the Alliance, DC, GM, and
Biomech all stated that there are little or no data to support
extending the application of the standard to 4,536 kilograms (10,000
pounds). In contrast, CU, Public Citizen, and several individual
commenters stated that the weight limit should be raised up to 4,536
kilograms (10,000 pounds) GVWR due to widespread use of sports utility
vehicles for family transportation and their concerns regarding
rollover risks associated with 15-passenger vans.
A significant percentage of light trucks are not yet subject to the
requirements of FMVSS No. 216. Specifically, Polk New Vehicle
Registration data show that out of a total of 8,800,000 new light
trucks registered in 2003, more than 44 percent (3,900,000) had a GVWR
between 2,722 kilograms (6,000 pounds) and 4,536 kilograms (10,000
pounds), and therefore are not subject to current requirements of FMVSS
No. 216. Given that the data in Table 3 show a greater average roof
crush for heavier light trucks, the agency believes that this fleet
data suggest the need to regulate a greater percentage of light trucks
traveling on U.S. highways.
In addition, sales of new light trucks with a GVWR of 2,722
kilograms (6,000 pounds) to 4,536 kilograms (10,000 pounds) GVWR have
been increasing rapidly. According to Polk New Vehicle Registry, the
number of new registrations has increased from 2.3 million for model
year 1997 to 3.5 million for model year 2001.\52\ That number
represents 21 percent of the total number of light duty vehicles sold
in the United States in 2001. With the increasing sales volume of
``heavier'' light trucks, the number of passenger-carrying vehicles not
subject to the requirements of FMVSS No. 216 is increasing every year.
---------------------------------------------------------------------------
\52\ http://www.polk.com/products/new_vehicle_data.asp.
---------------------------------------------------------------------------
Also, we note that analysis of recent safety data shows that a
significant number of serious and fatal injuries occur during rollovers
in light trucks with a GVWR between 2,722 kilograms (6,000 pounds) and
4,536 kilograms (10,000 pounds). Specifically, 412 belted, not fully
ejected occupants are killed or seriously injured every year in light
trucks with a GVWR between 2,722 kilograms (6,000 pounds) and 4,536
kilograms (10,000 pounds) involved in rollover crashes resulting in
roof intrusion. Among these 412 fatally or seriously injured occupants,
we estimate that 129 could potentially benefit from upgraded roof crush
resistance requirements because they suffered their most severe (MAIS)
injury from roof contact.
Further, the number of light trucks with a GVWR between 2,722
kilograms (6,000 pounds) and 4,536 kilograms (10,000 pounds) involved
in a fatal rollover increased from 1,187 in 1997 to 1,589 in 2001.
DC and other commenters also argued that larger vehicles have a
higher ratio of height-to-width, which tends to produce less intrusion
in rollover crashes. However, no data were provided to support their
argument. In addition, Table 3 shows that 55 percent of light trucks
with a GVWR between 2,722 kilograms (6,000 pounds) and 4,536 kilograms
(10,000 pounds) that were involved in rollover crashes experienced at
least 15 cm (5.9 inches) of vertical roof intrusion. At the same time,
only 49 percent of light trucks with a GVWR of less than 2,722
kilograms (6,000 pounds) and 32 percent of passenger vehicles
experienced similar intrusion levels. Because the likelihood of roof
intrusion exceeding 15 cm (5.9 inches) is relatively similar among the
three groups of vehicles (and actually slightly higher for heavier
light trucks), these data do not suggest a lesser risk of roof contact
to occupants of light trucks with a GVWR between 2,722 kilograms (6,000
pounds) and 4,536 kilograms (10,000 pounds) in rollovers than to
occupants of lighter vehicles.
Our research indicates that many vehicles with a GVWR between 2,722
kilograms (6,000 pounds) and 4,536 kilograms (10,000 pounds) would
comply with current roof crush requirements of FMVSS No. 216. The
agency recently conducted roof crush testing on six vehicles with a
GVWR over 2,722 kilograms (6,000 pounds).\53\ All six vehicles met the
requirements of the current standard.\54\ We anticipate that the
compliance burdens associated with the proposed roof strength
requirements would be similar for vehicles with a GVWR between 2,722
kilograms (6,000 pounds) and 4,536 kilograms (10,000 pounds) as for
those lighter vehicles already subject to the requirements of FMVSS No.
216.
---------------------------------------------------------------------------
\53\ The six vehicles were: MY 1999 Ford E-150, MY 2001
Chevrolet Tahoe, MY 2002 Dodge Ram, MY 2003 Ford F-150, MY 2003 Ford
Expedition, and MY 2003 Chevy Express.
\54\ See Docket Number NHTSA-2005-22143.
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Finally, we are cognizant that increasing roof crush resistance
requirements could potentially add weight to the roof and pillars,
thereby increasing the vehicle center of gravity (CG) height and
rollover propensity.\55\ NHTSA examined the potential effects of a more
stringent roof crush requirement on vehicle rollover propensity. In
Appendix A to the Preliminary Regulatory Impact Analysis (PRIA), the
agency estimated the change in the CG height for two vehicles \56\ with
a finite element model that was used to evaluate possible design
changes and costs associated with this proposal. NHTSA then analyzed
six additional vehicles to provide a more representative estimate of
potential impacts. Our analysis indicates that the potential CG height
increases \57\ were very small; i.e., within the tolerance of what can
be physically measured.
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\55\ NHTSA estimates that about one third of all vehicles would
require changes to meet the proposed standard.
\56\ MY 1998 Dodge Neon and MY 1999 Ford E-150
\57\ Less than 1 mm for the Neon, and less than 2 mm for the F-
150.
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We also note that, in addition to structural integrity of the
vehicle, other new vehicle design considerations affecting the handling
and stability of the vehicle, such as vehicle track width, suspension
system, and placard tire pressure, have a commensurate or even greater
influence on rollover propensity.
[[Page 49234]]
An expanded discussion of the potential impacts is included in the
PRIA.
Further, previous NHTSA research evaluated four Nissan vehicles
modified for increased roof strength.\58\ The CG height for each
modified vehicle varied between 25 mm above and 25 mm below the
baseline vehicle. We also note that the CG height varied by more than 6
mm even between two similar baseline vehicles. This data further
supports the agency's findings that increases in the roof structural
strength will not have a physically measurable influence on the CG
height, and that influence on CG is commensurate with other vehicle
design characteristics and production variations.
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\58\ ``Design Modification for a 1989 Nissan Pick-up--Final
Report,'' DOT HS 807 925, NTIS, Springfield, Virginia, 1991.
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For the foregoing reasons, the agency proposes to extend the
application of FMVSS No. 216 to MPVs, trucks and buses with a GVWR of
4,536 kilograms (10,000 pounds) or less.
2. Vehicles Manufactured in Two or More Stages
For vehicles manufactured in two or more stages,\59\ other than
vehicles incorporating chassis-cabs,\60\ we are proposing giving their
manufacturers the option of certifying them to either the existing roof
crush requirements of FMVSS No. 220, School Bus Rollover Protection, or
the proposed new roof crush requirements of FMVSS No. 216. FMVSS No.
220 uses a horizontal plate, instead of the angled plate of Standard
No. 216.
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\59\ Vehicles manufactured in two or more stages are assembled
by several independent entities with the ``final stage''
manufacturer assuming the ultimate responsibility for certifying the
completed vehicle.
\60\ Under 49 CFR 567.3, chassis-cab means an incomplete
vehicle, with a completed occupant compartment, that requires only
the addition of cargo-carrying, work-performing, or load-bearing
components to perform its intended functions.
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Multi-stage vehicles are aimed at a variety of niche markets, most
of which are too small to be serviced economically by single stage
manufacturers. Some multi-stage vehicles are built from chassis-cabs
that have intact roof designs. Others are built from less complete
vehicles and are designed to service particular needs--often
necessitating the addition by the final stage manufacturer of its own
roof or occupant compartment. In considering requirements applicable to
this segment of the motor vehicle market, the agency must consider a
number of principles.
First, the mandate in the Vehicle Safety Act that the agency
consider whether a proposed standard is appropriate for the particular
type of motor vehicle for which it is prescribed is intended to ensure
that consumers are provided an array of purchasing choices and to
preclude standards that will effectively eliminate certain types of
vehicles from the market. See Chrysler Corporation v. Dept. of
Transportation, 472 F.2d 659,679 (6th Cir. 1972) (agency may not
establish a standard that effectively eliminates convertibles and
sports cars from the market). Second, the agency may not provide
exemptions for single manufacturers beyond those specified by statute.
See Nader v. Volpe, 320 F. Supp. 266 (D.D.C. 1970), motion to vacate
affirmance denied, 475 F.2d 916 (DC Cir. 1973). Finally, the agency
must provide adequate compliance provisions applicable to final stage
manufacturers. Failing to provide these manufacturers with a means of
establishing compliance would render a standard impracticable as to
them. See National Truck Equipment Association v. National Highway
Traffic Safety Administration, 919 F.2d 1148 (6th Cir. 1990)
(``NTEA'').
One of the traditional ways in which the agency has handled
compliance issues associated with multi-stage vehicles has been simply
to exclude from the scope of the standard all vehicles, single-stage as
well as multi-stage, within the upper GVWR range of light vehicles,
typically from 8,500 pounds GVWR to 10,000 pounds GVWR. Many of the
multi-stage vehicles manufactured for commercial use cluster in that
GVWR range.\61\
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\61\ As the Court noted in NTEA (at 1158): ``The Administration
could meet the needs of final-stage manufacturers in many ways. It
could exempt from the steering column displacement standard all
commercial vehicles or all vehicles finished by final-stage
manufacturers. It could exempt those vehicles for which a final-
stage manufacturer cannot pass through the certification from the
incomplete vehicle manufacturers. It could change the pass through
regulations. It could reexamine the issue and prove that final-stage
manufacturers can conduct engineering studies, and then provide in
the regulation that such studies exceed the capacities of final-
stage manufacturers.''
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The agency traditionally took this approach because the agency
historically was of the view that it could not subject vehicles built
in multiple-stages to any different requirements than those built in a
single-stage. That was because the agency had construed 49 U.S.C.
30111(b)(3), which instructs the agency to ``consider whether a
proposed standard is reasonable, practicable, and appropriate for the
particular type of motor vehicle . . . for which it is prescribed,'' as
precluding such an approach.
In reaching that conclusion, the agency had focused on a comment in
the Senate Report:
In determining whether any proposed standard is ``appropriate''
for the particular type of motor-vehicle * * * for which it is
prescribed, the committee intends that the Secretary will consider
the desirability of affording consumers continued wide range of
choices in the selection of motor vehicles. Thus it is not intended
that standards will be set which will eliminate or necessarily be
the same for small cars or such widely accepted models as
convertibles and sports cars, so long as all motor vehicles meet
basic minimum standards. Such differences, of course, would be based
on the type of vehicle rather than its place of origin or any
special circumstances of its manufacturer.
Focusing on the last sentence of that passage, the agency had
concluded that the number of stages in which a vehicle was built was a
``special circumstance[s] of its manufacturer,'' (see, e.g., 60 FR
38749, 38758, July 28, 1995), rather than considering a multi-stage
vehicle to be a ``type of vehicle.'' But see NTEA (at 1151) (Noting the
agency's regulation defining ``incomplete vehicle'' as ``as assemblage
consisting as a minimum, of frame and chassis structure, power train,
steering system, suspension system, and braking system, to the extent
that those systems are to be part of the completed vehicle that
requires further manufacturing operations * * * to become a completed
vehicle. 49 CFR 568.3 (1989).''
We have reconsidered our historical view in light of relevant case
law and our experience with the compliance difficulties imposed on
final stage manufacturers. We note that the language we had previously
considered to be a limitation does not appear in the statutory text.
Nothing in the statutory text implies that Congress intended that
incomplete vehicles not be deemed a vehicle type subject to special
consideration during the regulatory process. We believe the sentence
found in the Senate Report was intended to avoid regulatory
distinctions based on manufacturer-specific criteria (such as place of
production or manner of importation). This is consistent with the
Court's conclusion in Nader v. Volpe, supra, that the agency cannot
give exemptions to particular manufacturers beyond those provided by
the statute.
We also had overlooked the existence of relevant physical
attributes of multi-stage vehicles. Most multi-stage vehicles have
distinct physical features related to their end use. Especially in the
context of the difficulties of serving niche markets, the physical
limitations of incomplete vehicles can adversely affect the ability of
multi-stage manufacturers
[[Page 49235]]
to design safety performance into their completed vehicles.
Further, as previously applied, our interpretation limits our
ability to secure increases in safety. Excluding all vehicles within a
given GVWR range from a safety requirement because of the possible
compliance difficulties of some of those vehicles means not obtaining
the safety benefits of that requirement for any of those vehicles.
Likewise, applying less stringent requirement to all of those vehicles
because of multi-stage considerations would also entail a loss of
safety benefits.
It would be perverse to conclude that Vehicle Safety Act permits us
to exclude all vehicles within a certain GVWR range primarily based on
the compliance difficulties of multi-stage vehicles within that range,
but not to exclude only the multi-stage vehicles within that range,
thus enabling consumers to obtain the safety benefits of regulating the
other vehicles within that weight range.
In the context of this rulemaking, we believe it appropriate to
consider incomplete vehicles, other than those incorporating chassis-
cabs, as a vehicle type subject to different regulatory requirements.
We anticipate that final stage manufacturers using chassis cabs to
produce multi-stage vehicles would be in position to take advantage of
``pass-through certification'' of chassis cabs, and therefore do not
propose including such vehicles in the category of those for whom this
optional compliance method is available.
Thus, we are proposing to allow final stage manufacturers to
certify non-chassis-cab vehicles to the roof crush requirements of
FMVSS No. 220, as an alternative to the requirements of FMVSS No. 216.
We decided to propose this approach instead of excluding most multi-
stage vehicles by proposing to exclude all vehicles with a GVWR above
8,500 pounds. The latter approach would have excluded some vehicles,
e.g., 15-passenger vans and vehicles built from chassis-cabs, that we
tentatively conclude should be subject to the proposed upgraded
requirements of FMVSS No. 216.
The requirements in FMVSS No. 220 have been effective for school
buses, but we are concerned that they may not be as effective for other
vehicle types. As noted above, the FMVSS No. 216 test procedure results
in roof deformations that are consistent with the observed crush
patterns in the real world for light vehicles. Because of this, NHTSA's
preference would be to use the FMVSS No. 216 test procedure for light
vehicles. However, this approach would fail to consider the
practicability problems and special issues for multi-stage
manufacturers.
In these circumstances, NHTSA believes that the requirements of
FMVSS No. 220 appear 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. Several states already require
``para-transit'' vans and other buses, which are typically manufactured
in multiple stages, to comply with the roof crush requirements of FMVSS
No. 220. These states include Pennsylvania, Minnesota, Wisconsin,
Tennessee, Michigan, Utah, Alabama, and California. NHTSA tentatively
concludes that these state requirements show the burden on multi-stage
manufacturers for evaluating roof strength in accordance with FMVSS No.
220 is not unreasonable, and applying FMVSS No. 220 to these vehicles
would ensure that there are some requirements for roof crush protection
where none currently exist.
3. Convertibles
Currently, convertibles are excluded from the requirements of FMVSS
No. 216. FMVSS No. 216 does not define the term ``convertibles.''
However, S3 of 49 CFR 571.201 defines ``convertibles'' as vehicles
whose A-pillars are not joined with the B-pillars (or rearmost pillars)
by a fixed, rigid structural member. In a previous rulemaking, NHTSA
stated that ``open-body type vehicles'' \62\ are a subset of
convertibles and are therefore excluded from the requirements of FMVSS
No. 216.\63\
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\62\ An open-body type vehicle is a vehicle having no occupant
compartment top or an occupant compartment top that can be installed
or removed by the user at his convenience. See Part 49 CFR 571.3.
\63\ See 56 FR 15510 (April 17, 1991).
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However, NHTSA has reassessed its position with respect to ``open-
body type vehicles.'' Specifically, we believe that we were incorrect
in stating that ``open-body type vehicles'' were a subset of
convertibles because some open-body type vehicles do not fall under the
definition of convertibles in S3 of FMVSS No. 201. For example, a Jeep
Wrangler has a rigid structural member that connects the A-pillars to
the B-pillars. The Jeep Wrangler is an ``open-body type vehicle''
because it has a removable compartment top, but it does not fall under
the definition of convertibles because its A-pillars are connected with
the B-pillars through the structural member.
The agency believes that ``open-body type vehicles'' such as the
Jeep Wrangler are capable of offering roof crush protection over the
front seat area. Accordingly, the agency proposes to limit the
exclusion from the requirements of FMVSS No. 216 to only those vehicles
whose A-pillars are not joined with the B-pillars, thus providing
consistency with the definition of a convertible in S3 of FMVSS No.
201. To clarify the scope of the exemption for convertible vehicles, we
are proposing to add the definition of convertibles contained in S3 of
49 CFR 571.201 to the definition section in FMVSS No. 216.
The agency seeks comments on the following:
1. The number of vehicle lines that fall under the definition of
``open-body type vehicles,'' but do not fall under the definition of
convertibles.
2. The roof crush performance of open-body type vehicles that do
not fall under the definition of convertibles.
3. The feasibility of requiring that open-body type vehicles meet
FMVSS No. 216.
B. Proposed Amendments to the Roof Strength Requirements
1. Increased Force Requirement
Currently, FMVSS No. 216 requires that the lower surface of the
test plate not move more than 127 mm (5 inches), when it is used to
apply a force equal to 1.5 times the unloaded weight of the vehicle to
the roof over the front seat area. For passenger cars, the applied
force cannot exceed 22,240 Newtons (5,000 pounds). As a result,
passenger cars that have an unloaded weight above 1,512 kilograms
(3,333 pounds) are, in effect, tested to a less stringent requirement
than other passenger cars and light trucks under the current
standard.\64\ Based on the agency analysis of crash data, as well as
comments in response to the October 2001 RFC, NHTSA is proposing to
require that the roof over the front seat area withstand the 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.
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\64\ 5,000 pounds / 1.5 = 3,333 pounds.
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Increase Applied Force to 2.5 Times the Unloaded Vehicle Weight
NHTSA 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
[[Page 49236]]
requirements of FMVSS No. 216 experienced vertical roof intrusion
greater than the test plate movement limit of 127 mm (5 inches).
Specifically, from the 1997-2002 NASS-CDS data, we estimate that 32
percent of passenger cars and 49 percent of light trucks with a GVWR
under 2,722 kilograms (6,000 pounds) exceed 150 mm (5.9 inches) of
vertical roof intrusion. Further, 55 percent of light trucks with a
GVWR greater than 2,722 kilograms (6,000 pounds) and less than or equal
to 4,536 kilograms (10,000 pounds) exceed 150 mm (5.9 inches) of
vertical roof intrusion.\65\ Based on these data, we have tentatively
concluded that the test force should be increased.
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\65\ Table 3 shows the percent of roof-involved rollover
vehicles with particular degrees of vertical roof intrusion by
vehicle body type.
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Accordingly, NHTSA is proposing to increase the applied force
requirement to 2.5 times \66\ the unloaded vehicle weight in order to
better protect vehicle occupants by reducing the amount of roof
intrusion in rollover crashes. The agency believes that reduction in
roof intrusion would better protect vehicle occupants.
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\66\ NHTSA's rationale for selecting a factor of 2.5 is
discussed below in the response to public comments about the
appropriate level of the factor.
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Public Citizen and several individual commenters on the October
2001 RFC suggested that NHTSA require a vehicle to withstand an applied
force of 3.0 to 3.5 times the unloaded vehicle weight in order to
better replicate dynamic forces occurring in rollover crashes. Carl
Nash suggested that the agency propose a new requirement that the roof
must sustain 1.5 times vehicle's GVWR before 127 mm (5 inches) of plate
movement and sustain a force that does not drop more than 10 percent
during the test. After the force of 1.5 times the GVWR has been
achieved, the force should be increased to 2.5 times the vehicle's GVWR
without any further roof deformation.
In response to these comments, the agency notes that it previously
conducted a study (Rains study) \67\ that measured peak forces
generated during quasi-static testing under FMVSS No. 216 and under 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. 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 concluded that 2.5 was a good representation
of the observed range of peak force-to-weight ratio.
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\67\ Glen C. Rains and Mike Van Voorhis, ``Quasi Static and
Dynamic Roof Crush Testing,'' DOT HS 808-873, 1998.
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The agency believes that manufacturers will comply with this
standard by strengthening reinforcements in roof pillars, by increasing
the gauge of steel used in roofs or by using higher strength materials.
The agency estimates that 32 percent of all current passenger car and
light truck models will need changes to meet the 2.5 load factor
requirement.
The agency has tentatively concluded that 2.5 constitutes a load
factor appropriate to enhance roof crush performance. As described
above, roof crush performance is but one of several measures necessary
to reduce rollover related fatalities and injuries. Continued
improvements in driver behavior, combined with advanced technologies
such as electronic stability control systems and lane departure
warnings will further reduce those fatalities and injuries.
Further, NHTSA's New Car Assessment Program (NCAP) provides a
strong incentive for manufacturers to design vehicles that will attain
favorable Static Stability Factors (representing the relatively
numerous tripped rollovers) and that will perform well in the dynamic
maneuver (representing the relatively few untripped rollovers), as well
as meeting the minimum load factor of 2.5.
Safety Analysis and Forensic Engineering (SAFE) and Syson-Hille and
Associates argued that solely attaining the peak force is not a useful
indicator of roof crush resistance performance because the peak forces
often drop significantly due to breaking glass and other structural
failures. They recommend an energy absorption requirement in order to
prevent roof collapse after initial peak forces are attained. The
agency has not previously considered adding an energy absorption
requirement to FMVSS No. 216 and would have to conduct significant
additional analysis in order to evaluate the energy absorption
requirement and determine appropriate parameters for testing.
Accordingly, the agency is not proposing an energy absorption
requirement in this document. Nevertheless, the agency would welcome
comments on energy absorption test described by SAFE and Syson-Hille.
Eliminate 22,240 Newton Force Limit for Passenger Cars
At the inception of the standard, some passenger cars were not
subjected to the full requirements of the standard, which mandated the
roof over the front seat area to withstand the force of 1.5 times the
unloaded vehicle weight. For passenger cars, this force was limited to
22,240 Newtons (5,000 pounds). That meant that heavier passenger cars
were not tested at 1.5 times their unloaded vehicle weight. In fact,
every passenger car weighing more than 1,512 kg (3,333 pounds) was
subjected to less stringent requirements. The purpose of this 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.\68\ 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 explained below, the agency
tentatively concludes that occupants of passenger cars weighing more
than 1,512 kg (3,333 pounds) are sustaining rollover-related injuries
and therefore require the same level of roof crush protection as other
vehicles subject to the standard.
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\68\ See 54 FR 46276.
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While passenger car rollover propensity is lower than it is for
light trucks, these vehicles can and do experience rollover crashes.
Recent crash data indicate that this is just as true for passenger cars
with unloaded vehicle weight of over 1,512 kg (3,333 pounds), as it is
for cars with lower unloaded vehicle weights. Specifically, out of an
annually estimated 6,274 seriously or fatally injured belted and not
fully ejected occupants of passenger cars involved in rollovers
resulting in roof intrusion, an estimated 1,460 (23 percent) were in
passenger cars that had an unloaded vehicle weight of over 1,512 kg
(3,333 pounds). Further, corporate average fuel economy (CAFE) data
have shown that from 1991 to 2001, the average weight of passenger cars
has
[[Page 49237]]
increased more than 7 percent.\69\ This trend suggests that more
passenger cars are being subjected to less stringent roof crush
resistance requirements each year. Based on these data, the agency
believes that occupants of passenger vehicles with unloaded vehicle
weight of over 1,512 kg (3,333 pounds) should be afforded the same
level of roof crush protection that is being offered by lighter
passenger cars and light trucks.
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\69\ http://www.nhtsa.dot.gov/cars/rules/CAFE/NewPassengerCarFleet.htm.
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In addition, we note that the manufacturers already produce heavier
passenger cars that exceed the current requirements of the standard.
Recently, the agency tested several passenger cars with an unloaded
weight of near or over 1,512 kilograms (3,333 pounds). The roof of each
vehicle withstood the force of at least 1.5 times the unloaded vehicle
weight. For example, MY 2002 Ford Crown Victoria with an unloaded
vehicle weight of 1,788 kilograms (3,942 pounds) withstood an applied
force of almost 2 times the unloaded vehicle weight (3671 kilograms
(8,093 pounds)) before 127 mm (5 inches) of plate movement was
attained. A MY 2004 Lincoln LS with an unloaded vehicle weight of 1,663
kilograms (3,666 pounds) withstood an applied force of slightly greater
than 2.5 times (4,290 kilograms, (9,458 pounds)) the unloaded vehicle
weight before 127 mm (5 inches) of plate movement was attained.
2. Headroom Requirement
The current standard requires that the lower surface of the test
device not move more than 127 mm (5 inches) under the specified applied
force. The purpose of the requirement is to limit the amount of roof
intrusion into the occupant compartment. However, the agency now
believes that the 127 mm (5 inch) limit is not the most effective way
to ensure that front seat area occupants are protected from roof
intrusion into the occupant compartment. Specifically, we are concerned
that this requirement does not provide adequate protection to front
outboard occupants of vehicles with a small amount of occupant headroom
and may impose a needless burden on vehicles with a large amount of
occupant headroom. For example, in a full size van with a substantial
amount of pre-crush headroom, the 127 mm (5 inch) plate movement limit
ensures that the collapsed portion of the roof would not contact the
front seat occupants. However, in a low roofline sports vehicle, the
127 mm (5 inch) plate movement limit might allow the crushed portion of
the roof to contact the head of an average size front seat occupant.
Therefore, the agency is proposing a more direct limit on headroom
reduction that would prohibit any roof component from contacting a
seated 50th percentile male dummy under the application of a force
equivalent to 2.5 times the unloaded vehicle weight. 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.
In response to the October 2001 RFC, Ford, Nissan, GM, DC, and
Biomech commented that real-world data indicate that it is not possible
to estimate quantifiable benefits of headroom reduction limits.
However, Ford also suggested that reducing the roof/pillar deformation
might benefit belted occupants if it results in the occupant not
contacting the roof.
In contrast, Public Citizen and numerous individual commenters
asserted that a minimum headroom clearance requirement should be
established because they believe that roof crush is related to head and
neck injury. Nash stated that limiting the extent and character of roof
intrusions can virtually eliminate the risks of serious head and neck
injury to restrained occupants in rollover crashes. Nash suggested that
NHTSA define headroom reduction limits by using a 50th percentile dummy
seat in the front outboard seat. Public Citizen and several other
commenters suggested that the standard contain an occupant survival
space/non-encroachment zone, which would not be intruded upon during
the test, using a 95th percentile dummy.
The 95th percentile Hybrid III male dummy has not been incorporated
into 49 CFR Part 572, Anthropomorphic Test Devices, and is not yet
available for compliance purposes. When the dummy is available, the
agency will consider whether it is appropriate to propose using this
dummy for compliance testing.
To help evaluate the value of a minimum headroom requirement, NHTSA
performed statistical analysis and published its findings in a report
entitled, ``Determining the Statistical Significance of Post-Crash
Headroom for Predicting Roof Contact Injuries to the Head, Neck, or
Face during FMVSS No. 216 Relevant Rollovers.'' \70\ This report
examined the effect of post-crash headroom (defined as the vertical
distance from the top of the occupant's head to the top of the roof
liner over the occupant's head after rollover) on injuries to the head,
neck, or face from contact with a roof component. We examined light
duty vehicles that rolled more than one-quarter turn to the side or
end-over-end and did not collide with fixed objects. The vehicle
occupants were adults who were belted and seated in the front outboard
seats and who were not ejected. Based on this report, the agency
estimates that 14 percent of the non-ejected, belted occupants sitting
in the two front outboard seats suffered a roof contact injury to the
head, neck, or face, and 0.1 percent died as a result of such an
injury.
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\70\ See Docket Number NHTSA-2005-22143.
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The agency analyzed crash data using two sets of headroom
measurement parameters from NCAP/FMVSS No. 208 frontal testing and CU
testing. Using NCAP/FMVSS No. 208 headroom measurement parameters, we
estimate that 9 percent of occupants with post-crash headroom above the
top of their head experienced roof contact injuries to the head, neck,
or face, compared to 34 percent for occupants with post-crash headroom
below the top of their head. Using CU vehicle headroom measurement
parameters, we estimate that 10 percent of occupants with post-crash
headroom above the top of their head experienced roof contact injuries
to the head, neck, or face, compared to 32 percent for occupants with
post-crash headroom below their head. After conducting bivariate and
multivariate analyses, we conclude that positive post-crash headroom
(residual space over the occupant's head after the rollover) reduced
the likelihood of suffering a roof contact injury to the head, neck, or
face. This real world data shows quantifiable benefits of limiting
headroom reduction.
As previously stated, the agency is proposing to prohibit any roof
component or the test device from contacting a seated 50th percentile
male Hybrid III dummy under the specified applied force. However, the
agency is concerned that there may be some low roofline vehicles \71\
in which the 50th percentile Hybrid III dummy would have relatively
little available headroom when positioned properly in the seat. That
is, we are 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. Accordingly, NHTSA
requests comments on whether any additional or substitute requirements
would be
[[Page 49238]]
appropriate for low roofline vehicles in order to make the standard
practicable.
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\71\ Ford GT, Lamborghini Gallardo.
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The agency believes that many vehicles subject to the current
requirements of FMVSS No. 216 would meet the proposed limit on headroom
reduction. In the recent tests of 20 vehicles of various types and
sizes in which the roofs were crushed to 254 mm (10 inches) of
displacement, thirteen vehicles had remaining headroom under an applied
force of 2.5 times the unloaded vehicle weight. These thirteen vehicles
were randomly distributed through the various vehicle types. Based on
these tests, the agency believes that vehicle manufacturers are capable
of complying with the proposed headroom requirements. In response to
the concerns expressed by SEMA with respect to installation of sunroofs
and moon roofs, we note that one of the tested vehicles was a Nissan
Quest equipped with a Sky View\TM\ glass-paneled roof consisting of a
sunroof and two separate glass panels. This vehicle withstood the force
of up to 2.8 times the unloaded vehicle weight with 3 inches of
displacement.
Finally, in conjunction with the proposed headroom requirement,
NHTSA is proposing to create a definition for ``roof component,'' which
is similar to the definition found in the NASS-CDS. Specifically, a
``roof component'' would include the A-pillar, B-pillar, front header,
rear header, roof side rails, roof, and all the corresponding interior
trim. Due to vast variations in roof designs, the agency proposes a
``no-contact'' requirement for all roof components, as opposed to only
the actual roof structure. The agency requests comments on the proposed
definition.
C. Proposed Amendments to the Test Procedures
1. Retaining the Current Test Procedure
To test compliance, the vehicle is secured on a rigid horizontal
surface, and a steel rectangular plate is angled and positioned on the
roof to simulate vehicle-to-ground contact over the front seat area.
This plate is used to apply the specified force to the roof structure.
Plate position and angle. In response to the October 2001 RFC, the
agency received several suggestions regarding the current quasi-static
test procedure. Specifically, CU suggested establishing a new plate
position, for which the specific application points would be (1) the
top of the A-pillar; (2) the top of the rear most pillar, either the B-
pillar on a pickup, C-pillar on sedans or the D-pillar on station
wagons, SUVs or minivans; and (3) the horizontal and vertical axes at
the center of the roof side, usually about the top of the B-pillar. CU
and several individual commenters recommended that a more
representative plate angle should be 45-degrees for vehicles with a
taller, narrower body configuration. SAFE stated that the roll angle
should be increased in an attempt to simulate the translational effect
of the vehicle traveling across the ground.
In response, NHTSA reviewed NASS-CDS crash data to examine roof
deformation patterns and compare real-world roof damage to compliance
tests.\72\ The agency also compared its findings to the previous study
on roof deformation patterns.\73\ The agency evaluated the damage to
the A- and B-pillars, roof rails and roof plane of the vehicles. Based
on the NASS-CDS crash data, we believe that the current test procedure
is capable of applying loads resulting in crush patterns consistent
with those that occur in the real world.
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\72\ See Docket Number NHTSA-1999-5572-95.
\73\ Michael J. Leigh and Donald T. Willke, ``Upgraded Rollover
Roof Crush Protection: Rollover Test and NASS Case Analysis,''
Docket NHTSA-1996-1742-18, June 1992.
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To further validate the crush patterns of the current FMVSS No. 216
compliance test, the agency evaluated previous tests that compared
deformation patterns of multiple inverted drop tests to the quasi-
static test procedure at different levels of crush. The tests showed a
correlation in deformation patterns, and this correlation increased as
the crush levels became more severe.
The agency also evaluated a previous dynamic guardrail test to
compare deformation patterns of a dynamic test procedure to the current
quasi-static test. A guardrail initiated a dynamic rollover on a 1989
Nissan pickup truck. The resulting rollover produced one roof-to-ground
impact. The agency recorded the intrusion levels throughout the area of
the vehicle roof. The deformation pattern and intrusion magnitudes of
the dynamic rollover were compared to a static crush test of the same
vehicle model. The resulting comparison plot showed good linear
correlation between the two deformations.\74\
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\74\ See Docket No. NHTSA-2005-22143.
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NHTSA also conducted a finite element modeling study to examine the
effect of using alternative roll and pitch angles for the current FMVSS
No. 216 test procedure.\75\ A model of a 1998 Dodge Caravan was used to
simulate extended FMVSS No. 216 tests for approximately 127 mm (5
inches) of plate motion using a variety of roll and pitch angles. The
simulations predicted that the Caravan roof would attain similar
amounts of deformation at a lower force level using 10-degree pitch and
45-degree roll (10-45) application angles compared to the current 5-
degree pitch and 25-degree roll (5-25) application angles. In addition,
a 1998 Chevrolet S10 pickup model was analyzed in subsequent
simulations, but led to less conclusive results.
---------------------------------------------------------------------------
\75\ ``Roof Crush Research: Load Plate Angle Determination and
Initial Fleet Evaluation.'' Docket No. NHTSA-2005-22143.
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The results of the finite element modeling study were sufficiently
encouraging to conduct a series of modified FMVSS No. 216 tests. Two
tests were conducted on Dodge Caravan, Chevrolet S10, and 2002 Ford
Explorer vehicles using both the current 5-25 degree application angles
as well as using modified 10-45 degree application angles. Each test
was conducted until 254 mm (10 inches) of load plate movement was
achieved.
The roof damage produced by the two test configurations was
generally similar. The tests using 10-45 degree application angles had
some additional lateral damage. However, the damage was localized near
the roof side rail and did not extend laterally to the midline of the
vehicle. The force distribution applied to the front and back of the
load plate changed considerably between the two test configurations.
The test configuration using the 10-45 degree application angles
applied almost all of the force to the forward ram located near the
front of the load plate. Comparatively, the 5-25 configuration applied
only two-thirds of the force to the front ram. Based on the similarity
of the post-test damage patterns and general force levels, the agency
concluded that there was not sufficient reason to propose a change in
the load plate configuration at this time.
Testing without windshield and/or side windows in place. Public
Citizen, CU, and several individual commenters stated that the quasi-
static test should be conducted without the windshield and/or side
glass. The comments stated that the glass usually breaks after the
first quarter-turn, resulting in virtually no support to the roof on
subsequent rollovers, and that the roof crush severity substantially
increases after the integrity of the windshield is breached.
The agency believes that windshields provide some structural
support to the roof even after the windshield breaks because the force-
deflection plots in some of the recent test vehicles (e.g., Ford
Explorer, Ford Mustang, Toyota Camry, Honda CRV) show little or no drop
in force level after the windshield
[[Page 49239]]
integrity was compromised.\76\ Further, examination of real-world
rollover crashes indicates that the windshield rarely separates from
the vehicle, and therefore, does provide some crush resistance. Because
NHTSA believes that the vehicle should be tested with all structural
components that would be present in a real-world rollover crash, we
decline to propose testing without the windshield or other glazing.
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\76\ See id.
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Near and far side testing. NHTSA received comments from Public
Citizen and the Center for Injury Research regarding near and far side
testing.\77\ The comments 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. Therefore, the comments suggested that
NHTSA require that both sides of the same vehicle withstand the force
equal to 2.5 times the unloaded vehicle weight. That is, after the
force is applied to one side of the vehicle, the vehicle is then
repositioned and the force is applied on the opposite side of the roof
over the front seat area. Public Citizen cited a recent paper by
researchers at Delphi Automotive and Saab, which compared the injury
risk depending on the seating position of an occupant relative to the
direction of the rollover crash.\78\ From this study, Public Citizen
concluded that belted, non-ejected occupants on the far side suffer 12
times the risk of serious injuries compared to belted, non-ejected
occupants on the near side of the rolling vehicle.
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\77\ Near side is the side toward which the vehicle begins to
roll and far side is the trailing side of the roll.
\78\ Parenteau, Chantal, Madana Gopal, David Viano. ``Near and
Far-Side Adult Front Passenger Kinematics in a Vehicle Rollover.''
SAE Technical Paper 2001-01-0176, SAE 2001 World Congress, March
2001.
---------------------------------------------------------------------------
In response, NHTSA conducted six tests (2 Lincoln LS, Ford Crown
Victoria, Chrysler Pacifica, Nissan Quest, Land Rover Freelander), in
which both sides of the vehicle roof were crushed. Using the current
FMVSS No. 216 test plate angles, the first side was crushed up to
approximately 100 mm (4 inches) of plate movement. The test plate
motion compromised the windshield structure in each vehicle. The
similar procedure was performed on the opposite side of the vehicle.
However, the crush was extended up to 254 mm (10 inches) of plate
movement. Detailed reports for these tests are available in the NHTSA
docket.\79\
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\79\ See Docket Number NHTSA-2005-22143.
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In summary, the first and second side force deflection curves track
similarly for the Pacifica and Quest. For the Crown Victoria, the first
and second side force curves tracked similarly except between 50-90 mm
of crush. During that portion of the curve, the local peak was reduced
17 percent on the second side. However, after 90 mm, the second side
force curve tracked similarly to the previously tested Crown Victoria
\80\ that was crushed to 254 mm (10 inches) of plate movement. For the
Freelander, the second side force curve showed an increase in force
over the first side, starting at approximately 40 mm of plate movement.
As a result, the local peak force was increased by approximately 20
percent on the second side. In contrast, the second side force curve of
the Lincoln LS showed a decrease in force starting at approximately 40
mm of plate movement. As a result, the local peak force was decreased
by approximately 20 percent on the second side.
---------------------------------------------------------------------------
\80\ ``Roof Crush Research: Load Plate Angle Determination and
Initial Fleet Evaluation.'' Docket No. NHTSA-2005-22143.
---------------------------------------------------------------------------
To evaluate the repeatability of the tests, the agency performed
the identical test procedure on a second Lincoln LS. For the second LS
test, both the first and second side force curves tracked similarly to
the curves of the first LS test up to approximately 40 mm. However, the
local peak for the first side was slightly lower than the first test
and the local peak for the second side was slightly higher than the
first test on the second side. As a result, the difference in the local
peak force between the first and second side was approximately 10
percent.
In conclusion, the agency believes that some vehicles may have
weakened or strengthened far side roof structures as a result of a near
side impact. However, based on the few vehicles tested, NHTSA does not
have enough information to make a decision on the merits of testing
both sides of the roof over the front seat area. The agency plans to
conduct further research before it proposes rulemaking action in this
area.
On July 26, 2004, JP Research, Inc. submitted an evaluation of the
Delphi Automotive and Saab research paper (Delphi research paper) \81\
relied upon by Public Citizen.\82\ JP Research discussed the paper with
one of the principal authors and verified that the paper contained
errors. Previously, Public Citizen concluded that belted, non-ejected
occupants on the far side suffer 12 times the risk of serious injuries
compared to belted, non-ejected occupants on the near side of the
rolling vehicle. However, as a result of correcting the errors, the
ratio changes from 12 to 1, to between 2.4 and 1.
---------------------------------------------------------------------------
\81\ Parenteau, Chantal, Madana Gopal, David Viano. ``Near and
Far-Side Adult Front Passenger Kinematics in a Vehicle Rollover.''
SAE Technical Paper 2001-01-0176, SAE 2001 World Congress, March
2001.
\82\ See Docket Number NHTSA-1999-5572-93.
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In preparing this document, NHTSA analyzed NASS-CDS (1997 to 2002)
data to evaluate the Delphi research paper with respect to merits of
testing both sides of the roof over the front seat area. The analysis
included belted front outboard adults who were not fully ejected in a
manner similar to the Delphi research paper, but it further restricted
the analysis to vehicles that rolled only two to four quarter turns to
the side. We estimate the risk of a serious injury, defined as a
maximum AIS injury of 3 or greater, to be 29 seriously injured persons
per 1000 ``far side'' occupants and 30 seriously injured persons per
1000 ``near side'' occupants for a ratio of about 1 to 1. Based on this
analysis, the agency believes that there is no significant increase in
risk for far side belted, non-ejected occupants.
In summary, NHTSA continues to believe that the quasi-static test
procedure is repeatable and capable of simulating real-world rollover
deformation patterns. Based on the deformation patterns observed in
NASS-CDS cases, finite element modeling, and various controlled vehicle
testing, the agency believes that changing the test plate angle is not
necessary. Further, the agency believes that the vehicle should be
tested with all structural components that would be present in a real-
world rollover crash, and therefore we decline to propose testing
without the windshield or other glazing. Finally, the agency plans to
further evaluate the safety need for testing both sides of the roof
over the front seat area on the same vehicle, before proposing such a
requirement.
2. Dynamic Testing
In response to the October 2001 RFC, we received several comments
suggesting that the agency adopt some form of dynamic testing of roof
crush resistance. Specifically, CU and Stilson Consulting urged the
agency to adopt dynamic testing to replicate better the influence of
variable crush patterns and vehicle dynamic elements that occur in
real-world crashes. Further, Hans Hauschild, Hogan, Donald Slavik, and
Coben and Associates suggested that NHTSA adopt the SAE J996 inverted
drop test because it better replicates real-world rollover dynamics.
The Alliance argued that dynamic testing was unrepeatable. DC and
Biomech stated that they have not
[[Page 49240]]
evaluated dynamic rollover testing and do not know what injury criteria
might be appropriate for assessing dynamic performance. NTEA stated
that the benefits of adopting dynamic roof crush testing are unclear.
Further, NTEA stated that dynamic rollover testing was neither
economically nor technologically feasible.
GM, DC, and Biomech stated that inverted drop testing is not
repeatable and cannot accurately represent real-world rollovers.
Further, Ford stated that the drop test does not represent the multi-
axis, real-world condition with respect to time duration of impact, and
does not replicate centrifugal forces on the occupant because the
velocity of roof rail impact with the ground in a rollover is a
function of the vehicle's roll rate, translational velocity and
vertical velocity. Public Citizen asserted that the SAE J996 inverted
drop test does not accurately reproduce the lateral sliding forces
present in a rollover crash. Carl Nash stated that the inverted drop
test can be useful, but does not properly simulate the lateral friction
forces that are typical in rollovers on the road.
Based on research discussed in Section V(A) NHTSA believes that the
inverted drop test does not replicate real-world rollovers better than
the current quasi-static method of testing. Further, the inverted drop
test does not produce results as repeatable as the quasi-static method.
Specifically, NHTSA believes that the drop test would not apply a
consistent directional force among tested vehicles because of the
vehicle roll that is introduced after the initial roof impact.
Depending on the geometry of the roof and hood, vehicles may experience
different load paths as they roll onto its hood or front-end structure.
Advocates for Highway Safety (Advocates) suggested that the agency
consider adopting a series of tests for ensuring adequate roof
strength. Specifically, Advocates suggested adopting a test similar to
the FMVSS No. 208 dolly test. Donald Friedman stated that NHTSA should
consider using the FMVSS No. 208 dolly test for research. By contrast,
the Alliance, GM, Nissan, Ford, and DC stated that the FMVSS No. 208
dolly test is not repeatable and does not emulate the dynamics of real-
world rollover crashes. Further, the test was not developed to predict
roof crush performance. Hauschild suggested that the FMVSS No. 208
dolly test, while appropriate for evaluating occupant retention for
belted and unbelted occupants, would not be appropriate for evaluating
roof strength. Slavik and Syson-Hille asserted that the FMVSS No. 208
dolly test is useful for examining potential occupant kinematics in
rollovers, but may not be feasible for pass/fail regulatory purposes
due to resultant variability in roof impacts and intrusion.
The FMVSS No. 208 dolly test was originally developed only as an
occupant containment test. The test was not developed to evaluate the
loads on specific vehicle components. The agency believes this test
lacks sufficient repeatability to serve as a structural component
compliance requirement.
Biomech Inc. suggested that the agency consider using the
Controlled Rollover Impact System (CRIS) device \83\ because it
overcomes the shortcomings of drop testing (lack of roll and
translational velocity-limiting time exposure of roof-to-ground
contact) by incorporating important test parameters (roll angle,
vertical and horizontal velocities and pitch and yaw of the vehicle).
Ford believes that the CRIS is able to create repeatable dynamic
rollover impact simulations for the first roof-to-ground impact. By
contrast, SAFE and several other individual comments suggested that the
conclusions drawn from the CRIS tests \84\ mischaracterize the real-
world rollover dynamics because the tests were designed to support the
hypothesis that roof crush does not cause occupant injuries.
---------------------------------------------------------------------------
\83\ The CRIS consists of a towed semi-trailer, which suspends
and drops a rotating vehicle from a support frame cantilevered off
the rear of the trailer.
\84\ Moffatt, E.A., Cooper, E.R., Croteau, J.J., Orlowski, K.F.,
Marth, D.R., and Carter, J.W. ``Matched-Pair Impacts of Rollcaged
and Production Roof Cars Using the Controlled Rollover Impact System
(CRIS),'' Society of Automotive Engineers, 2003-01-0172, Detroit,
Michigan, 2003.
---------------------------------------------------------------------------
The agency believes the CRIS device is helpful in understanding
occupant kinematics during rollover crashes. However, NHTSA believes
that the device does not provide the level of repeatability needed,
because the CRIS test is repeatable only up to the initial contact with
ground. After initial roof impact, the CRIS test allows the vehicle to
continue rolling, resulting in an unrepeatable test condition.
Lastly, NHTSA received several comments regarding the Jordan
Rollover System (JRS) test device. The JRS device rotates a vehicle
body structure on a rotating apparatus (``spit'') while the road
surface moves along the track and contacts the roof structure. Public
Citizen and the Center for Injury Research believe that the JRS test
can be conducted with dummies that demonstrate whether vehicle roof
performance meets objective injury and ejection criteria for belted and
unbelted occupants.
Although the agency is open to further investigating the JRS test,
we have no data regarding the repeatability of dummy injury and roof
intrusion measurements. In addition to data on repeatability, NHTSA
would need further information on its performance measures,
practicability, and relevance to real-world injuries.
In summary, NHTSA is not proposing a dynamic test procedure at this
time. As previously stated, the agency believes that the current test
procedure is repeatable and capable of simulating real-world rollover
deformation patterns. Further, the agency is unaware of any dynamic
test procedures that provide a sufficiently repeatable test
environment.
3. Revised Tie-Down Procedures
Based on recent testing described in Section V(C), NHTSA is
proposing to revise the vehicle tie-down procedure in order to improve
test repeatability. Specifically, the agency is proposing to specify
that the vehicle be secured with 4 vertical supports welded or fixed to
both the vehicle and the test fixture. If the vehicle support locations
are not metallic, a suitable epoxy or an adhesive could be used in
place of welding. Under the proposal, the vertical supports would be
located at the manufacturers' designated jack points. If the jack
points are not sufficiently defined, the vertical supports would be
located between the front and rear axles on the vehicle body or frame
such that the distance between the fore and aft locations is maximized.
If the jack points are located on the axles or suspension members, the
vertical stands would be located between the front and rear axles on
the vehicle body or frame such that the distance between the fore and
aft locations is maximized. All non-rigid body mounts would be made
rigid to prevent motion of the vehicle body relative to the vehicle
frame.
The agency believes this method of securing the vehicle would
increase test repeatability. Welding the support stands to the vehicle
would reduce testing complexity and variability of results associated
with the use of chains and jackstands. In addition, the agency believes
that using the jacking point for vertical support attachment is
appropriate because the jacking points are designed to accommodate
attachments and withstand certain loads without damaging the vehicle.
In previous comments to the Docket, Ford suggested that vehicle
overhangs should be supported by jackstands in
[[Page 49241]]
order to minimize vehicle distortion.\85\ However, the agency does not
believe that it is necessary to support the vehicle overhangs. In fact,
supporting the vehicle overhangs with jackstands could distort the
shape of the vehicle prior to testing.
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\85\ See Docket Number 94-097-N02-010.
---------------------------------------------------------------------------
4. Plate Positioning Procedure
Currently, the standard contains two test plate positioning
procedures. The primary procedure applies to most vehicles. It places
the midpoint of the forward edge of the lower surface of the test
device within 10 mm (0.4 inches) of the transverse vertical plane 254
mm (10 inches) forward of the forwardmost point on the exterior surface
of the roof. The secondary procedure applies to multipurpose passenger
vehicles and buses with raised or altered roofs, at the option of the
manufacturer. It places the midpoint of the rearward edge of the lower
surface of the test device within 10 mm (0.4 inches) of the transverse
vertical plane located at the rear of the roof over the front seat
area.
The agency is proposing to specify the primary test procedure for
all vehicles. The agency believes that this test plate positioning
procedure produces repeatable and reliable means for testing roof
strength. The agency believes that the secondary plate positioning test
procedure produces rear edge plate loading onto the roof of some raised
and altered roof vehicles that cause excessive deformation
uncharacteristic of real-world rollover crashes. Because an optimum
plate position cannot be established for all roof shapes, the testing
of some raised and altered roof vehicles will result in loading the
roof rearward of the front seat area. However, NHTSA believes that this
is preferable to edge contact because edge contact produces localized
concentrated forces upon the roof typically resulting in excessive
shear deformation of a small region. In some circumstances, the plate
will essentially punch through the sheet metal instead of loading the
structure. The agency believes that removing the secondary plate
position would also make vehicle testing more objective and
practicable. Accordingly, the agency proposes to eliminate the
secondary positioning procedure.
VIII. Other Issues
A. Agency Response to Hogan Petition
As previously discussed, on May 6, 1996, the agency received a
petition for rulemaking from Hogan.\86\ The petitioner claimed that the
test requirements of FMVSS No. 216 bear no relationship to real-world
rollover crash conditions, and therefore, should be replaced with a
more realistic test such as inverted drop test. On January 8, 1997,
NHTSA granted this petition, believing that the inverted drop test had
merit for further agency consideration.
---------------------------------------------------------------------------
\86\ See Docket No. 2005-22143.
---------------------------------------------------------------------------
After careful evaluation of the issues presented by the Hogan
petition, the agency has decided against adopting the inverted drop
test or other dynamic test procedures because we believe that these
tests are not better than the current quasi-static test in replicating
real-world rollover crash conditions.
The agency fully discussed alternatives to the current quasi-static
test in Section VII(C)(1), (2). First, NHTSA conducted a series of
inverted drop tests and concluded that the tests were not better than
quasi-static tests in representing vehicle-to-ground interaction
occurring during rollover, and were more difficult to conduct because
they require suspending and inverting the vehicle.\87\ Second, NHTSA
conducted dynamic rollover tests and observed that dynamic testing
created test conditions so severe it was difficult to discriminate
between good and bad performing roof structures, and that the occupant
kinematics and roof crush during dynamic rollover were unrepeatable.
The agency is unaware of any dynamic test procedures that provide a
sufficiently repeatable test environment. Finally, we believe quasi-
static testing adequately represent real world dynamic deformation
patterns occurring in rollovers.
---------------------------------------------------------------------------
\87\ For more details on the inverted drop test evaluation
please see Section VII(C)(1), and Glen C. Rains and Mike Van
Voorhis, ``Quasi Static and Dynamic Roof Crush Testing,'' DOT HS
808-873, 1998.
---------------------------------------------------------------------------
For the reasons discussed above and in Section VI(C)(1), NHTSA is
withdrawing the open rulemaking on the Hogan petition. Instead, the
agency proposes to adopt the new roof strength requirements discussed
elsewhere in this document.
B. Agency Response to Ford and RVIA Petition
On June 11, 1999, Ford \88\ and RVIA \89\ submitted petitions for
reconsideration to the April 27, 1999, final rule (64 FR 22567), which
established the primary and secondary test plate positioning procedures
specified in S7.3 and S7.4, respectively. Petitioners argued that the
secondary plate positioning test procedure produced rear edge plate
loading onto the roof of some raised and altered roof vehicles that
caused excessive deformation uncharacteristic of real-world rollover
crashes. Specifically, petitioners argued that positioning the test
plate such that the rear edge of the plate is at the rearmost point of
the front occupant area resulted in stress concentration, which
produced excessive deformation and roof penetration. Petitioners
stressed that this type of loading is uncommon to real-world rollovers.
Consequently, petitioners asked the agency to reconsider adopting the
secondary plate positioning procedure for raised or altered roof
vehicles. Ford also provided computer analysis that showed non-
distributed loading near the edge plate contact when the secondary
plate position was used.
---------------------------------------------------------------------------
\88\ Docket No. NHTSA-99-5572-2 (http://dmses.dot.gov/docimages/pdf37/57806_web.pdf).
\89\ Docket No. NHTSA-99-5572-3 (http://dmses.dot.gov/docimages/pdf39/62547_web.pdf).
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As discussed in Section VII(C)(4), the agency is proposing to
eliminate the secondary test procedure (49 CFR Sec. 571.216, S7.4) and
to require that all vehicles subject to FMVSS No. 216 use the primary
test procedure in S7.3. Specifically, all vehicles would be tested such
that the midpoint of the forward edge of the lower surface of the test
plate is within 10 mm (0.4 inches) of the transverse vertical plane 254
mm (10 inches) forward of the forwardmost point on the exterior surface
of the roof.
C. Request for Comments on Advanced Restraints
In evaluating the effectiveness of seat belt restraints in
mitigating rollover-related injury, NHTSA developed a rollover test
device, the ``rollover restraints tester'' (RRT).\90\ RRT was used to
simulate rollover conditions and evaluate the effectiveness of: (1)
Typical 3-point lap and shoulder belt system; (2) D-ring \91\
adjustments, (3) belt pretensioners; (4) integrated seats; \92\ and (5)
inflatable tubular torso restraint (ITTR) in preventing occupant
excursion in a rollover event.\93\
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\90\ See http://www-nrd.nhtsa.dot.gov/pdf/nrd-01/Esv/esv16/98S8W34.PDF.
\91\ D-ring is the upper anchorage of the three-point seat belt
assembly.
\92\ An integrated seat is a seat that includes the seat belt
mechanism and assembly in the seat instead of on the B-pillar.
\93\ Rains, Glen C., et al., ``Evaluation of Restraints
Effectiveness in Simulated Rollover Conditions,'' 16th International
Technical Conference on the Enhanced Safety of Vehicles, 98-S8-W-34,
Windsor, Canada, 1998.
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Following testing, we arrived at the following conclusions: (1) The
maximum head excursion was much higher during the test (when dummy was
upside down in the restraint), compared to static pre- and post-test
head excursion measurements; (2) raising the D-ring decreased the dummy
head vertical and horizontal excursion
[[Page 49242]]
in both 3-point lap and shoulder belt system and ITTR; (3) compared to
conventional seats, the integrated seat significantly reduced occupant
excursion; (4) initiating belt pretensioners before testing the
integrated seat (thus simulating pre-rollover activation of the
pretensioners) provided additional benefit; and (5) compared to a
conventional lap and shoulder seat belt system, the ITTR more
effectively restrained the vertical and longitudinal excursion of the
dummy.
In addition to the agency testing, several other studies indicate
that pretensioned restraint systems can reduce the amount of vertical
head excursion compared to the typical 3-point lap and shoulder belt
system.\94\ By contrast, a Nissan study showed that the maximum
occupant injury values in rollovers did not decrease for occupants with
activated pretensioners, compared to occupants without
pretensioners.\95\
---------------------------------------------------------------------------
\94\ Pywell, James et al., ``Characterization of Belt Restraint
Systems in Quasi-Static Vehicle Rollover Tests,'' SAE Paper 973334,
Society of Automotive Engineers, Warrendale, PA, 1997; and Moffatt,
Edward et al., ``Head Excursion of Seat Belted Cadaver, Volunteers
and Hybrid III ATD in a Dynamic/Static Rollover Fixture,'' SAE Paper
973347, Society of Automotive Engineers, Warrendale, PA, 1997.
\95\ Hare, Barry et al., ``Analysis of Rollover Restraint
Performance with and without Seat Belt Pretensioner at Vehicle
Trip,'' SAE Paper 2002-01-0941, Society of Automotive Engineers,
Warrendale, PA, 2002.
---------------------------------------------------------------------------
In response to the October 2001 RFC, we received several
suggestions with respect to enhancing occupant protection in rollover
crashes by means of using better seat belts. Slavik suggested amending
FMVSS Nos. 208 and 209 to require the use of pretensioners that
activate in rollovers before the vehicle rolls 90-degrees, and
retractors that lock and remain locked for at least five seconds after
the pretensioner is fired. Syson-Hille and Associates stated that NHTSA
should continue its efforts to increase seat belt use rates, and
consider amending FMVSS Nos. 208, 209, and 210 to ensure that belts
provide enhanced occupant protection and remain fastened in rollover
crashes.
On August 7, 2003, NHTSA met with representatives of the Automotive
Occupant Restraints Council (AORC) to discuss seat belt technologies
that have the potential for improving occupant protection in rollover
crashes.\96\ AORC made a presentation entitled, ``Seat Belt
Technologies Improving Occupant Protection in Rollover.'' In the
presentation, AORC discussed several seat belt technologies including
pretensioning systems, electric retractors, inflatable seat belts, and
four-point harnesses.
---------------------------------------------------------------------------
\96\ See Docket Number NHTSA 2003-14622-10.
---------------------------------------------------------------------------
Since advanced restraints have the potential for contributing to
the comprehensive effort to reduce rollover-related injuries and
fatalities, the agency would like comments on the following issues:
1. Could requiring advanced restraints systems on vehicles
significantly reduce head excursion and decrease occupant injury values
in rollovers?
2. Which kinds of advanced restraints systems are the most
effective at minimizing vertical occupant excursion during rollovers?
3. What is the current state of technology with respect to
pretensioning systems that are capable of activating in a rollover
event as well as other crash modes? What are the associated costs?
4. What procedures would be appropriate for testing performance of
advanced seat belt systems? At what values should the pretension sensor
activate?
5. What would be an appropriate limit for the force exerted by a
pretensioning system on an occupant and how would it be measured?
IX. Benefits
The agency examined the relationship between injuries in rollover
crashes and the amount of post-crash headroom and found a statistically
significant relationship between injury rates and instances in which
the roof intruded below the occupant's normal seating height. The
injury patterns were less serious in cases in which roof intrusion did
not encroach on the pre-crash headroom of the occupant; i.e., when the
deformed roof structure did not intrude below the top of the seated
occupant's head.
Using two alternative analytical approaches, the agency prepared
two estimates of safety benefits resulting from the proposed roof crush
resistance upgrade. The second approach was developed to cure
shortcomings in the first approach.
Under the first approach, the agency analyzed specific cases of
actual injuries and fatalities involving belted occupants that were not
fully ejected during rollovers. Using FARS and NASS-CDS databases, we
analyzed only those cases in which the roof intrusion occurred over the
injured occupant's seat, and the MAIS was in fact caused by roof
contact with the occupant. We sought to estimate how an injured or
killed occupant in each specific case might have benefited from a
stronger roof structure. The agency believes that this estimate is
conservative since limiting roof crush might also benefit those
occupants who have roof crush related injuries that are not MAIS. That
is some occupants are injured as a result of roof crush, but their most
severe injury resulted from something other than roof crush.
Based on the first approach, the agency estimates that the proposed
requirements would prevent 13 fatalities and 793 non-fatal injuries. We
estimate 39 annual equivalent lives saved.
We note, however, that because we narrowed the case sample to
reflect specific crash characteristics, the agency has a very limited
sample of relevant cases at its disposal. Further, some of the relevant
cases within that sample lacked some data elements, resulting in data
gaps. At the same time, certain individual cases were assigned very
large sample weight by the NASS-CDS database. This distorted the
overall profile of relevant injuries (case weight spikes). As a result,
the agency believes that the characteristics of this limited sample may
not accurately represent the full benefits resulting from the proposed
roof crush resistance upgrade.
Under the second approach, the agency again examined the same
injury cases discussed in the first approach. However, in evaluating
actual crashes, the agency noted that post-crash negative headroom \97\
measurements available from FARS and NASS-CDS databases were related to
occupant's actual height. For example, the amount of post-crash
headroom in a vehicle occupied by a taller person would be different
from post-crash headroom of the same vehicle occupied by a shorter
person.
To better estimate how this proposal would benefit occupants of
varying heights, the agency assumed that the probability of occupant
height in each actual relevant rollover case would be equal to the
national distribution of occupant heights. That is, an occupant of any
size might have been involved in a crash that fits the agency's case
criteria. We calculated the odds of the occupant in each case being of
a height to benefit from the proposed requirements. This calculation
differed for each rollover case based on amount of actual roof
intrusion and vehicle design. As a result, the agency was able to use a
more refined case sample to estimate the benefits of the proposed
requirements. We were able to estimate how any occupant would benefit
from stronger roofs in each actual crash case.
[[Page 49243]]
This approach minimized case weight spikes inherent to the first
approach used to estimate potential benefits of this proposal.
Under the second approach, the agency estimates that the proposed
requirements would prevent 44 fatalities and 498 non-fatal injuries. We
estimate 55 equivalent lives saved annually.
---------------------------------------------------------------------------
\97\ Negative headroom means post-crash headroom that is below
the occupant's seated height.
---------------------------------------------------------------------------
We note however, that the second approach assumes a random
relationship between the height of drivers and the headroom in vehicles
that they purchase. The agency believes that the relationship between
vehicle headroom and occupant size is insignificant in most cases. It
is likely that taller drivers adjust the seat positions to prevent
uncomfortable proximity to the roof.
The agency requests comments on both approaches for estimating
benefits of this proposal. A more detailed discussion of the estimated
benefits associated with this proposal are in the PRIA.
X. Costs
The agency estimates that upgrading the roof crush resistance
standard would result in annual fleet costs of $88 to $95 million. The
total fleet cost is based on structural changes and impacts on fuel
economy. The average cost of strengthening the roof structure of
vehicles that do not meet the proposed requirements is estimated to be
$10.67 per vehicle, with an annual fleet cost of $58.6 million. We
estimate that approximately 32 percent of the current vehicle fleet
would need improvements to meet the proposed upgraded requirements. The
average fuel economy impact cost is estimated to be $5.33 to $6.69 per
vehicle, with an annual fleet cost of $29.4 to $36.9 million.
We estimated the structural costs using finite element vehicle
modeling in which various components of two vehicles that do not meet
the proposed requirements were upgraded until the two vehicles met the
proposed requirements, and roof crush tests of twenty recent model year
vehicles. The two vehicles were a 1998 Plymouth Neon passenger car, and
a 1999 Ford E-150 van. The initial baseline crush tests of the Neon and
Ford E-150 showed that each vehicle could withstand a roof crush force
of about 1.9 times its unloaded weight. Neither vehicle would comply
with the proposed requirements because the roof over the front seat
area cannot withstand a force of 2.5 times the unloaded vehicle weight.
Through an iterative process, improvements were reflected within
the finite element model until the Neon and E-150 could withstand a
roof crush force of about 20 percent greater than 2.5 times their
vehicle weight.\98\
---------------------------------------------------------------------------
\98\ The agency assumes that manufacturers would design their
vehicles so that they can meet a standard with a 20% compliance
margin in order to address production and performance variability
concerns. Vehicle manufacturers normally include compliance margins
in their vehicle designs to assure that each vehicle could pass the
applicable test requirements. In this case, a safety margin of 20
percent would require that vehicles withstand applied force of 3
times the unloaded vehicle weight (1.2 x 2.5).
---------------------------------------------------------------------------
We estimate the price increase for the purchaser (consumer cost) to
improve the Neon roof strength to 2.5 times the unloaded vehicle weight
with a 20 percent compliance margin to be $3.02, and the consumer cost
to improve the E-150 roof strength to 2.5 times the unloaded vehicle
weight with a 20 percent compliance margin to be $29.66.\99\ Further,
we estimated the average cost of strengthening the roof structure of
vehicles that do not meet the proposed requirements to be $10.67.\100\
---------------------------------------------------------------------------
\99\ These improvements include changes in the material strength
(steel gage, for example) of various vehicle components.
\100\ The consumer cost average estimate was weighted for
relative roof strength of different vehicles and corresponding sales
volumes.
---------------------------------------------------------------------------
In addition to finite element vehicle modeling, the agency tested a
representative sample of 20 recent model year vehicles to estimate what
percentage of the overall fleet already complies with the proposed
requirements. Based on the current sales data, these 20 vehicles
represent a current vehicle fleet population of approximately 5.9
million vehicles. Seven of the 20 vehicles tested by the agency failed
the proposed roof crush resistance requirements. The seven failing
vehicles represent a vehicle fleet population of approximately 1.9
million. The cost of upgrading these 1.9 million vehicles would be
$20.3 million.
We estimate that 17 million new vehicles would be subject to the
proposed requirements. Accordingly, before accounting for weight gain
implications, we estimate the total fleet cost to be $58.6 million (17
million / 5.9 million x $20.3 million).
Additionally, the changes made to increase roof strength may
require heavier materials and or reinforcements that could increase the
weight of the vehicle. This weight increase may adversely affect the
vehicle's fuel economy and thus increase the amount of fuel it consumes
over its lifetime. We estimate that the average weight gain necessary
to upgrade the roof crush resistance of the vehicle fleet of 17 million
vehicles is 0.6 lbs per vehicle. We estimate that this added weight
would result in additional fuel expenditures in the amount of $29.4 to
$36.9 million per year, resulting in the total annual fleet costs of
$88 to $95 million ($58.6 + $29.4) or ($58.6 + $36.9).\101\
---------------------------------------------------------------------------
\101\ For details on the fuel economy impacts, please see the
PRIA.
---------------------------------------------------------------------------
XI. Lead Time
NHTSA proposes that the manufacturers be required to comply with
the new requirements for FMVSS No. 216 on and after the first September
1 that occurs more than three years (36 months) after the issuance of
the final rule. Based on recent agency testing, the agency estimates
that 68 percent of the current fleet already complies with the proposed
roof strength requirements. Accordingly, the proposed roof strength
requirements would not necessitate fleet-wide roof structure changes.
NHTSA believes that vehicle manufacturers have engineering and
manufacturing resources that would enable vehicles to meet the new
requirements three years after the publication of the final rule. We
request comments on the lead time necessary to comply with the proposal
requirements.
XII. Request for Comments
How Do I Prepare and Submit Comments?
Your comments must be written and in English. To ensure that your
comments are correctly filed in the Docket, please include the docket
number of this document in your comments. Your comments must not be
more than 15 pages long.\102\ We established this limit to encourage
you to write your primary comments in a concise fashion. However, you
may attach necessary additional documents to your comments. There is no
limit on the length of the attachments. Please submit two copies of
your comments, including the attachments, to Docket Management at the
address given above under ADDRESSES. Comments may also be submitted to
the docket electronically by logging onto the Docket Management System
Web site at http://dms.dot.gov. Click on ``Help & Information'' or
``Help/Info'' to obtain instructions for filing the document
electronically. If you are submitting comments electronically as a PDF
(Adobe) file, we ask that the documents submitted be scanned using
Optical Character Recognition (OCR) process, thus allowing the agency
to search and
[[Page 49244]]
copy certain portions of your submissions.\103\
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\102\ See 49 CFR 553.21.
\103\ Optical character recognition (OCR) is the process of
converting an image of text, such as a scanned paper document or
electronic fax file, into computer-editable text.
---------------------------------------------------------------------------
Please note that pursuant to the Data Quality Act, in order for
substantive data to be relied upon and used by the agency, it must meet
the information quality standards set forth in the OMB and DOT Data
Quality Act guidelines. Accordingly, we encourage you to consult the
guidelines in preparing your comments. OMB's guidelines may be accessed
at http://www.whitehouse.gov/omb/fedreg/reproducible.html. DOT's
guidelines may be accessed at http://dmses.dot.gov/submit/DataQualityGuidelines.pdf.
How Can I Be Sure That My Comments Were Received?
If you wish Docket Management to notify you upon its receipt of
your comments, enclose a self-addressed, stamped postcard in the
envelope containing your comments. Upon receiving your comments, Docket
Management will return the postcard by mail.
How Do I Submit Confidential Business Information?
If you wish to submit any information under a claim of
confidentiality, you should submit three copies of your complete
submission, including the information you claim to be confidential
business information, to the Chief Counsel, NHTSA, at the address given
above under FOR FURTHER INFORMATION CONTACT. In addition, you should
submit two copies, from which you have deleted the claimed confidential
business information, to Docket Management at the address given above
under ADDRESSES. When you send a comment containing information claimed
to be confidential business information, you should include a cover
letter setting forth the information specified in our confidential
business information regulation.\104\
---------------------------------------------------------------------------
\104\ See 49 CFR Part 512.
---------------------------------------------------------------------------
Will the Agency Consider Late Comments?
We will consider all comments that Docket Management receives
before the close of business on the comment closing date indicated
above under DATES. To the extent possible, we will also consider
comments that Docket Management receives after that date. If Docket
Management receives a comment too late for us to consider in developing
a final rule (assuming that one is issued), we will consider that
comment as an informal suggestion for future rulemaking action.
How Can I Read the Comments Submitted By Other People?
You may read the materials placed in the docket for this document
(e.g., the comments submitted in response to this document by other
interested persons) by going to the street address given above under
ADDRESSES. The hours of the Docket Management System (DMS) are
indicated above in the same location.
You may also read the materials on the Internet. To do so, take the
following steps:
(1) Go to the Web page of the Department of Transportation DMS
(http://dms.dot.gov/search/searchFormSimple.cfm).
(2) On that page type in the five-digit docket number cited in the
heading of this document. After typing the docket number, click on
``search.''
(3) On the next page (``Docket Search Results''), which contains
docket summary information for the materials in the docket you
selected, scroll down and click on the desired materials. You may
download the materials.
XIII. Rulemaking Analyses and Notices
A. Executive Order 12866 and DOT Regulatory Policies and Procedures
NHTSA has considered the impact of this rulemaking action under
Executive Order 12866 and the Department of Transportation's regulatory
policies and procedures. The Office of Management and Budget reviewed
this rulemaking document under E.O. 12866, ``Regulatory Planning and
Review.'' This rulemaking action has been determined to be significant
under Executive Order 12866 and the DOT Policies and Procedures because
of Congressional and public interest. This rulemaking action is not
economically significant because the estimated yearly costs do not
exceed $100 million. The total estimated recurring fleet cost for all
changes proposed by this document is $88 to $95 million. NHTSA is
placing in the public docket a PRIA describing the costs and benefits
of this rulemaking action.\105\ The costs and benefits are also
summarized in Sections IX and X above. We estimate that, if adopted,
this proposal would result in 13-44 fewer fatalities and 498-793 fewer
non-fatal injuries each year.
---------------------------------------------------------------------------
\105\ See Docket No. NHTSA-2005-22143.
---------------------------------------------------------------------------
B. Regulatory Flexibility Act
The Regulatory Flexibility Act of 1980 (5 U.S.C. 601 et seq.)
requires agencies to evaluate the potential effects of their proposed
rules on small businesses, small organizations and small governmental
jurisdictions. I have considered the possible effects of this
rulemaking action under the Regulatory Flexibility Act and certify that
it would not have a significant economic impact on a substantial number
of small entities.
Under 13 CFR 121.201, the Small Business Administration (SBA)
defines small business (for the purposes of receiving SBA assistance)
as a business with less than 750 employees. Most of the manufacturers
of recreation vehicles, conversion vans, and specialized work trucks
are small businesses that manufacture vehicles in two or more stages.
Some of these manufacturers produce vehicles that would be subject to
the proposed requirements, as their GVWR is less than or equal to
10,000 pounds. While the number of these small businesses potentially
affected by this proposal is substantial, the economic impact upon
these entities will not be significant for the following reasons:
1. As indicated in Section VII(A)(2), we are proposing to allow
vehicles manufactured in two or more stages (other than chassis-cabs),
to certify to the roof crush requirements of FMVSS No. 220, instead of
FMVSS No. 216. This aspect of our proposal will afford significant
economic relief to small businesses because some of them are already
required by the States to certify to the requirements of FMVSS No. 220.
Thus, the proposal would not require additional expenditure by these
small businesses.
2. Small businesses using chassis cabs would be in position to take
advantage of ``pass-through certification,'' and therefore, are not
expected to incur any additional expenditures.
3. We believe that some of the vehicles manufactured by these small
businesses already comply with the proposed requirements.\106\
---------------------------------------------------------------------------
\106\ As discussed in Section X above, 68% of the current fleet
meets the proposed requirements.
---------------------------------------------------------------------------
In addition to small businesses that manufacture vehicles in two or
more stages, there are four manufacturers of passenger cars that are
small businesses.\107\ All of these manufacturers could be affected by
the proposed requirements. However, the economic impact upon these
entities will not be significant for the following reasons.
---------------------------------------------------------------------------
\107\ Avanti, Panoz, Saleen, Shelby.
---------------------------------------------------------------------------
1. While the average cost for roof crush resistance upgrades was
estimated at approximately $12 per vehicle, the cost of upgrading the
roof structures of
[[Page 49245]]
passenger cars is lower because we believe that this cost is a function
of weight of the vehicle. For example, the cost of upgrading the roof
structure of Dodge Neon, a passenger vehicle, was estimated at $3.
2. The agency believes that a cost increase of $3 to $12 would not
have a significant economic impact upon small businesses that
manufacture passenger cars because these costs can be passed onto the
consumer. This increase would represent, at most, less than one-half of
one tenth of a percent of the least expensive vehicle manufactured by
the four entities.\108\
---------------------------------------------------------------------------
\108\ Approximately $25,000.
---------------------------------------------------------------------------
3. We believe that some of the vehicles manufactured by these small
businesses already comply with the proposed requirements.\109\
---------------------------------------------------------------------------
\109\ As discussed in Section X above, 68% of the current fleet
meets the proposed requirements. We believe this may be especially
true for high performance vehicles typically manufactured by small
businesses.
---------------------------------------------------------------------------
4. Some of the vehicles manufactured by these small businesses are
convertibles not subject to this proposal.
C. National Environmental Policy Act
NHTSA has analyzed this proposal for the purposes of the National
Environmental Policy Act. The agency has determined that implementation
of this action would not have any significant impact on the quality of
the human environment. Upgrading the roof crush resistance standard may
impact the weight of the vehicles subject to that standard and
consequently result in the reduced fuel economy for these vehicles.
However, the agency believes that the resulting impact on environment
will be insignificant. A full discussion of fuel economy implications
is in the PRIA.
D. Executive Order 13132 (Federalism)
The agency has analyzed this rulemaking in accordance with the
principles and criteria contained in Executive Order 13132 and has
determined that it does not have sufficient federal implications to
warrant consultation with State and local officials or the preparation
of a federalism summary impact statement. The proposal would not have
any substantial impact on the States, or on the current Federal-State
relationship, or on the current distribution of power and
responsibilities among the various local officials.
E. Unfunded Mandates Act
The Unfunded Mandates Reform Act of 1995 requires agencies to
prepare a written assessment of the costs, benefits and other effects
of proposed or final rules that include a Federal mandate likely to
result in the expenditure by State, local or tribal governments, in the
aggregate, or by the private sector, of more than $100 million annually
($120.7 million as adjusted annually for inflation with base year of
1995). The assessment may be combined with other assessments, as it is
here.
This proposal is not likely to result in expenditures by State,
local or tribal governments or automobile manufacturers and/or their
suppliers of more than $120.7 million annually. The agency estimates
that upgrading the roof crush resistance standard would result in
annual fleet costs of $88 to $95 million. No expenditures by State,
local or tribal governments are expected. A full assessment of the
rule's costs and benefits is provided in the PRIA.
F. Civil Justice Reform
This NPRM would not have any retroactive effect. 49 U.S.C. 30161
sets forth a procedure for judicial review of final rules establishing,
amending, or revoking Federal motor vehicle safety standards. That
section does not require submission of a petition for reconsideration
or other administrative proceedings before parties may file suit in
court.
State action on safety issues within the purview of a Federal
agency may be limited or even foreclosed by express language in a
congressional enactment, by implication from the depth and breadth of a
congressional scheme that occupies the legislative field, or by
implication because of a conflict with a congressional enactment. In
this regard, we note that section 30103(b) of 49 U.S.C. provides,
``When a motor vehicle safety standard is in effect under this chapter,
a State or a political subdivision of a State may prescribe or continue
in effect a standard applicable to the same aspect of performance of a
motor vehicle or motor vehicle equipment only if the standard is
identical to the standard prescribed under this chapter.'' Thus, all
differing state statutes and regulations would be preempted.
Further, it is our tentative judgment that safety would best be
promoted by the careful balance we have struck in this proposal among a
variety of considerations and objectives regarding rollover safety. As
discussed above, this proposal is a part of a comprehensive plan for
reducing the serious risk of rollover crashes and the risk of death and
serious injury in those crashes. The objective of this proposal is to
increase the requirement for roof crush resistance only to the extent
that it can be done without negatively affecting vehicle dynamics and
rollover propensity. The agency has tentatively concluded that our
proposal would not adversely affect vehicle dynamics and cause vehicles
to become more prone to rollovers. In contrast, the agency believes
that either a broad State performance requirement for greater levels of
roof crush resistance or a narrower requirement mandating that
increased roof strength be achieved by a particular specified means,
would frustrate the agency's objectives by upsetting the balance
between efforts to increase roof strength and reduce rollover
propensity.
Increasing current roof crush resistance requirements too much
could potentially result in added weight to the roof and pillars,
thereby increasing the vehicle center of gravity (CG) height and
rollover propensity. In order to avoid this, we sought to strike a
careful balance between improving roof crush resistance and potentially
negative effects of too large an increase upon the vehicle's rollover
propensity.
We recognize that there is a variety of potential ways to increase
roof crush resistance beyond the proposed level. However, we believe
that any effort to impose either more stringent requirements or
specific methods of compliance would frustrate our balanced approach to
preventing rollovers from occurring as well as the deaths and injuries
that result when rollovers nevertheless occur.
First, we believe that requiring a more stringent level of roof
crush resistance for all vehicles could increase rollover propensity of
many vehicles and thereby create offsetting adverse safety
consequences. While the agency is aware of at least several current
vehicle models that provide greater roof crush resistance than would be
required under our proposal, requiring greater levels of roof crush
resistance for all vehicles could, depending on the methods of
construction and materials used, and on other factors, render other
vehicles more prone to rollovers, thus frustrating the agency's
objectives in this rulemaking.
Second, we believe that requiring vehicle manufacturers to improve
roof crush resistance by a specific method would also frustrate agency
goals. The optimum methods for addressing the risks of rollover crashes
vary considerably for different vehicles, and requiring specific
methods for improving roof crush resistance could interfere with the
efforts to develop optimal solutions. Moreover, some methods of
improving roof crush resistance are costlier than others. The resources
diverted to increasing roof strength using one of the costlier
[[Page 49246]]
methods could delay or even prevent vehicle manufacturers from
equipping their vehicles with advanced vehicle technologies for
reducing rollovers, such as Electronic Stability Control.
Based on the foregoing, if the proposal were adopted as a final
rule, it would preempt all conflicting State common law requirements,
including rules of tort law.
G. National Technology Transfer and Advancement Act
Under the National Technology Transfer and Advancement Act of 1995
(NTTAA) (Pub. L. 104-113), ``all Federal agencies and departments shall
use technical standards that are developed or adopted by voluntary
consensus standards bodies, using such technical standards as a means
to carry out policy objectives or activities determined by the agencies
and departments.'' As discussed in Section V, we evaluated the Society
of Automotive Engineers (SAE) inverted drop testing procedure, but
decided against proposing it. We were unable to identify any other
relevant technical standards. The agency requests comments on other
relevant technical standards.
H. Paperwork Reduction Act
Under the Paperwork Reduction Act of 1995 (PRA) (44 U.S.C. 3501, et
seq.), Federal agencies must obtain approval from the Office of
Management and Budget (OMB) for each collection of information they
conduct, sponsor, or require through regulations. NHTSA has reviewed
this proposal and determined that it does not contain collection of
information requirements.
I. Plain Language
Executive Order 12866 requires each agency to write all rules in
plain language. Application of the principles of plain language
includes consideration of the following questions:
Have we organized the material to suit the public's needs?
Are the requirements in the rule clearly stated?
Does the rule contain technical language or jargon that
isn't clear?
Would a different format (grouping and order of sections,
use of headings, paragraphing) make the rule easier to understand?
Would more (but shorter) sections be better?
Could we improve clarity by adding tables, lists, or
diagrams?
What else could we do to make the rule easier to
understand?
If you have any responses to these questions, please include them
in your comments on this proposal.
J. Privacy Act
Anyone is able to search the electronic form of all comments
received into any of our dockets by the name of the individual
submitting the comment (or signing the comment, 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://dms.dot.gov.
XVI. Vehicle Safety Act
Under 49 U.S.C. Chapter 301, Motor Vehicle Safety (49 U.S.C. 30101
et seq.), the Secretary of Transportation is responsible for
prescribing motor vehicle safety standards that are practicable, meet
the need for motor vehicle safety, and are stated in objective
terms.\110\ ``Motor vehicle safety standard'' means a minimum
performance standard for motor vehicles or motor vehicle equipment.
When prescribing such standards, the Secretary must consider all
relevant, available motor vehicle safety information.\111\ The
Secretary must also consider whether a proposed standard is reasonable,
practicable, and appropriate for the types of motor vehicles or motor
vehicle equipment for which it is prescribed and the extent to which
the standard will further the statutory purpose of reducing traffic
accidents and associated deaths.\112\ The responsibility for
promulgation of Federal motor vehicle safety standards is delegated to
NHTSA.
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\110\ 49 U.S.C. 30111(a).
\111\ 49 U.S.C. 30111(b).
\112\ Id.
---------------------------------------------------------------------------
In proposing to improve roof crush resistance, the agency carefully
considered these statutory requirements.
First, we believe that this proposal will meet the need for motor
vehicle safety because the proposed applied force requirement would
lead to stronger roofs and reduce the roof crush severity observed in
real world crashes, thus better protecting front seat occupants.
Second, we believe that the roof crush resistance standard subject
of this proposal is performance oriented because it requires only that
the vehicle roof be able to withstand a certain amount of applied
force. The standard does not specify the means by which the vehicle
must meet the standard.
Third, this proposal was preceded by a Request for Comments, which
facilitated the efforts of the agency to obtain and consider relevant
motor vehicle safety information. We anticipate receiving an even more
comprehensive array of relevant information in response to this
proposal. Further, in preparing this document, the agency carefully
evaluated previous agency research and vehicle testing that was
relevant to this proposal. We also conducted additional testing in
support of this document. Finally, the agency conducted a detailed
statistical analysis in order to estimate risks of death or injury
associated with roof crush, and to determine the relevant target
population and potential costs and benefits of our proposal. In sum,
this document reflects our consideration of all relevant, available
motor vehicle safety information.
Fourth, to ensure that requiring greater roof crush resistance is
practicable, the agency tested a number of vehicles and found that many
already comply with the proposed requirements, while others could
comply with relatively inexpensive modifications to their roof
structure. In response to the request for comments, the agency received
no indication that the proposed roof crush resistance requirements were
impracticable. However, based on the latest information from the
manufacturers and our own testing, we are proposing to amend the test
procedure for vehicles with raised or altered roofs to provide
additional assurance of practicability.\113\ To improve practicability
still further, the agency also proposes to revise the tie-down
procedure. Because we are especially concerned with practicability of
this proposal as it applies to vehicles manufactured in two or more
stages, we are proposing to allow the certification of these vehicles
to the roof crush requirements of FMVSS No. 220. In sum, we believe
that this proposal to improve roof crush resistance is practicable.
---------------------------------------------------------------------------
\113\ The agency previously adopted a ``secondary'' test
procedure for vehicles with raised or altered roofs which proved to
be an impracticable solution.
---------------------------------------------------------------------------
Fifth, the proposed regulatory text following this preamble is
stated in objective terms in order to specify precisely what
performance is required and how performance will be tested to ensure
compliance with the standard. Specifically, a large steel test plate
would be forced down onto the roof of a vehicle. If the displaced roof
structure does not contact the head or neck of the dummy seated inside
the vehicle, the vehicle passes the test. The agency believes that this
test procedure is sufficiently objective and would not result in any
uncertainty as to whether a given vehicle satisfies the proposed roof
crush resistance requirements.
[[Page 49247]]
Finally, we believe that this proposal is reasonable and
appropriate for motor vehicles subject to the proposed requirements. As
discussed elsewhere in this notice, the agency is concerned with the
amount of fatalities and serious injuries resulting from rollovers. Our
statistical data indicate that vehicles subject to the proposed
requirements are involved in rollovers that cause death and serious
injury. Accordingly, we believe that this proposal is appropriate for
vehicles that are or would become subject to FMVSS No. 216 because it
furthers the agency's objective of preventing deaths and serious
injuries associated with roof crush occurring in some of the rollovers.
XV. Proposed Regulatory Text
List of Subjects in 49 CFR Part 571
Motor vehicle safety, Reporting and recordkeeping requirements,
Tires.
In consideration of the foregoing, NHTSA proposes to amend 49 CFR
Part 571 as follows:
PART 571--[AMENDED]
1. The authority citation of Part 571 would continue to read as
follows:
Authority: 49 U.S.C. 322, 2011, 30115, 30166 and 30177;
delegation of authority at 49 CFR 1.50.
2. Section 571.216 would be amended by:
a. Revising S3 to read as set forth below;
b. Adding to S4, in alphabetical order, new definitions of
``Convertible'' and ``Roof component;''
c. Revising S5 to read as set forth below;
d. Removing S5.1;
e. Revising S7.1 through S7.6 to read as set forth below; and
f. Removing S8 through S8.4.
The revisions and additions read as follows:
Sec. 571.216 Standard No. 216; Roof crush resistance.
* * * * *
S3. Application. This standard applies to passenger cars, and to
multipurpose passenger vehicles, trucks and buses with a GVWR of 4,536
kilograms (10,000 pounds) or less. However, it does not apply to--
(a) School buses;
(b) Vehicles that conform to the rollover test requirements (S5.3)
of Standard No. 208 (Sec. 571.208) by means that require no action by
vehicle occupants;
(c) Convertibles, except for optional compliance with the standard
as an alternative to the rollover test requirement (S5.3) of Standard
No. 208; or
(d) Vehicles manufactured in two or more stages, other than chassis
cabs, that conform to the roof crush requirements (S4) of Standard No.
220 (Sec. 571.220).
S4. Definitions.
* * * * *
Convertible means a vehicle whose A-pillars are not joined with the
B-pillars (or rearmost pillars) by a fixed, rigid structural member.
* * * * *
Roof component means the A-pillar, B-pillar, roof side rail, front
header, rear header, roof, and all interior trim in contact with these
components.
* * * * *
S5. Requirements. When the test device described in S6 is used to
apply a force to either side of the forward edge of a vehicle's roof in
accordance with S7, no roof component or portion of the test device may
contact the head or the neck of the seated Hybrid III 50th percentile
male dummy specified in 49 CFR Part 572, Subpart E. The maximum applied
force in Newtons is at least 2.5 times the unloaded vehicle weight of
the vehicle, measured in kilograms and multiplied by 9.8. A particular
vehicle need not meet the requirements on the second side of the
vehicle, after being tested at one location.
* * * * *
S7.1 Secure the vehicle in accordance with S7.1(a) through (d).
(a) Support the vehicle off its suspension at a longitudinal
vehicle attitude of 0 degrees 0.5 degrees. Measure the
longitudinal vehicle attitude along both the driver and passenger sill.
Determine the lateral vehicle attitude by measuring the vertical
distance between a level surface and a standard reference point on the
bottom of the driver and passenger side sills. The difference between
the vertical distance measured on the driver side and the passenger
side sills shall not exceed 1 cm.
(b) Secure the vehicle with four stands. The locations for
supporting the vehicle are defined in S7.1(c) or (d). Welding is
permissible. The vehicle overhangs are not supported. Chains and wire
rope are not used to secure the vehicle. Fix all non-rigid body mounts
to prevent motion of the body relative to the frame. Close all windows,
close and lock all doors, and secure any moveable or removable roof
structure in place over the occupant compartment. Remove roof racks or
other non-structural components.
(c) For vehicles with manufacturer's designated jacking locations,
locate the stands at or near the specified location.
(d) For vehicles with undefined jacking locations, generalized
jacking areas, or jacking areas that are not part of the vehicle body
or frame, such as axles or suspension members, locate two stands in the
region forward of the rearmost axle and two stands rearward of the
forwardmost axle. All four stands shall be located between the axles on
either the vehicle body or vehicle frame.
S7.2(a) Adjust the seats and steering controls in accordance with
S8.1.2 and S.8.1.4 of 49 CFR 571.208.
(b) Place adjustable seat backs in the manufacturer's nominal
design riding position in the manner specified by the manufacturer.
Place any adjustable anchorages at the manufacturer's nominal design
position for a 50th percentile adult male occupant. Place each
adjustable head restraint in its lowest adjustment position. Adjustable
lumbar supports are positioned so that the lumbar support is in its
lowest adjustment position.
S7.3 Position the Hybrid III 50th percentile male dummy specified
in 49 CFR Part 572, Subpart E in accordance with S10.1 through
S10.6.2.2 of 49 CFR 571.208, in the front outboard designated seating
position on the side of the vehicle being tested.
S7.4 Orient the test device as shown in Figure 1 of this section,
so that--
(a) Its longitudinal axis is at a forward angle (in side view) of 5
degrees below the horizontal, and is parallel to the vertical plane
through the vehicle's longitudinal centerline;
(b) Its transverse axis is at an outboard angle, in the front view
projection, of 25 degrees below the horizontal.
S7.5 Maintaining the orientation specified in S7.4--
(a) Lower the test device until it initially makes contact with the
roof of the vehicle.
(b) Position the test device so that--
(1) The longitudinal centerline on its lower surface is within 10
mm of the initial point of contact, or on the center of the initial
contact area, with the roof; and
(2) The midpoint of the forward edge of the lower surface of the
test device is within 10 mm of the transverse vertical plane 254 mm
forward of the forwardmost point on the exterior surface of the roof,
including windshield trim, that lies in the longitudinal vertical plane
passing through the vehicle's longitudinal centerline.
S7.6 Apply force so that the test device moves in a downward
direction perpendicular to the lower surface of
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the test device at a rate of not more than 13 millimeters per second
until reaching the force level specified in S5. Guide the test device
so that throughout the test it moves, without rotation, in a straight
line with its lower surface oriented as specified in S7.4(a) and
S7.4(b). Complete the test within 120 seconds.
* * * * *
Issued: July 15, 2005.
Stephen R. Kratzke,
Associate Administrator for Rulemaking.
[FR Doc. 05-16661 Filed 8-19-05; 8:45 am]
BILLING CODE 4910-59-U