Federal Motor Vehicle Safety Standards; Roof Crush Resistance, 49223-49248 [05-16661]
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Federal Register / Vol. 70, No. 162 / Tuesday, August 23, 2005 / Proposed Rules
20590–0001. You must identify the FAA
Docket No. FAA–2005–22047 and
Airspace Docket No. 05–ANM–10 at the
beginning of your comments. You may
also submit comments through the
Internet at https://dms.dot.gov.
FOR FURTHER INFORMATION CONTACT: Ken
McElroy, Airspace and Rules, Office of
System Operations Airspace and AIM,
Federal Aviation Administration, 800
Independence Avenue, SW.,
Washington, DC 20591; telephone: (202)
267–8783.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested parties are invited to
participate in this proposed rulemaking
by submitting such written data, views,
or arguments, as they may desire.
Comments that provide the factual basis
supporting the views and suggestions
presented are particularly helpful in
developing reasoned regulatory
decisions on the proposal. Comments
are specifically invited on the overall
regulatory, aeronautical, economic,
environmental, and energy-related
aspects of the proposal.
Communications should identify both
docket numbers (FAA Docket No. FAA–
2005–22047 and Airspace Docket No.
05–ANM–10) and be submitted in
triplicate to the Docket Management
System (see ADDRESSES section for
address and phone number). You may
also submit comments through the
Internet at https://dms.dot.gov.
Commenters wishing the FAA to
acknowledge receipt of their comments
on this action must submit with those
comments a self-addressed, stamped
postcard on which the following
statement is made: ‘‘Comments to
Docket No. FAA–2005–22047 and
Airspace Docket No. 05–ANM–10.’’ The
postcard will be date/time stamped and
returned to the commenter.
All communications received on or
before the specified closing date for
comments will be considered before
taking action on the proposed rule. The
proposal contained in this action may
be changed in light of comments
received. All comments submitted will
be available for examination in the
public docket both before and after the
closing date for comments. A report
summarizing each substantive public
contact with FAA personnel concerned
with this rulemaking will be filed in the
docket.
Availability of NPRM’s
An electronic copy of this document
may be downloaded through the
Internet at https://dms.dot.gov. Recently
published rulemaking documents can
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16:15 Aug 22, 2005
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also be accessed through the FAA’s Web
page at https://www.faa.gov or the
Federal Register’s Web page at https://
www.gpoaccess.gov/fr/.
You may review the public docket
containing the proposal, any comments
received, and any final disposition in
person in the Dockets Office (see
ADDRESSES section for address and
phone number) between 9 a.m. and 5
p.m., Monday through Friday, except
Federal holidays. An informal docket
may also be examined during normal
business hours at the office of the
Regional Air Traffic Division, Federal
Aviation Administration, 1601 Lind
Avenue SW., Renton, Washington,
98055–4056.
Persons interested in being placed on
a mailing list for future NPRM’s should
contact the FAA’s Office of Rulemaking,
(202) 267–9677, for a copy of Advisory
Circular No. 11–2A, Notice of Proposed
Rulemaking Distribution System, which
describes the application procedure.
History
On June 29, 2005, the Salt Lake City
Air Route Traffic Control Center
(ARTCC) requested Federal Airway V–
343 be extended to accommodate
arriving instrument air traffic at BTM.
This action responds to this request.
Proposal
The FAA is proposing an amendment
to Title 14 Code of Federal Regulations
(14 CFR) part 71 to modify Federal
Airway V–343 by extending the airway
from the Bozeman, MT, VORTAC to the
initial approach fix for the RNAV
runway 15 approach to the BTM, MT.
The FAA has determined that this
proposed regulation only involves an
established body of technical
regulations for which frequent and
routine amendments are necessary to
keep them operationally current.
Therefore, this proposed regulation: (1)
Is not a ‘‘significant regulatory action’’
under Executive Order 12866; (2) is not
a ‘‘significant rule’’ under Department of
Transportation (DOT) Regulatory
Policies and Procedures (44 FR 11034;
February 26, 1979); and (3) does not
warrant preparation of a regulatory
evaluation as the anticipated impact is
so minimal. Since this is a routine
matter that will only affect air traffic
procedures and air navigation, it is
certified that this proposed rule, when
promulgated, will not have a significant
economic impact on a substantial
number of small entities under the
criteria of the Regulatory Flexibility Act.
List of Subjects in 14 CFR Part 71
Airspace, Incorporation by reference,
Navigation (air).
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The Proposed Amendment
In consideration of the foregoing, the
Federal Aviation Administration
proposes to amend 14 CFR part 71 as
follows:
PART 71—DESIGNATION OF CLASS A,
B, C, D, AND E AIRSPACE AREAS; AIR
TRAFFIC SERVICE ROUTES; AND
REPORTING POINTS
1. The authority citation for part 71
continues to read as follows:
Authority: 49 U.S.C. 106(g), 40103, 40113,
40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959–
1963 Comp., p. 389.
§ 71.1
[Amended]
2. The incorporation by reference in
14 CFR 71.1 of the FAA Order 7400.9M,
Airspace Designations and Reporting
Points, dated August 30, 2004, and
effective September 16, 2004, is
amended as follows:
Paragraph 6010(a)
Airways
*
*
*
Domestic VOR Federal
*
*
V–343 (Revised)
From Dubios, ID; Bozeman, MT, INT
Bozeman, MT, 302°T/284°M and Whitehall,
MT, 342°T/324°M Radials.
*
*
*
*
*
Issued in Washington, DC, on August 16,
2005.
Edith V. Parish,
Acting Manager, Airspace and Rules.
[FR Doc. 05–16748 Filed 8–22–05; 8:45 am]
BILLING CODE 4910–13–P
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
National Highway Traffic
Safety Administration (NHTSA),
Department of Transportation.
ACTION: Notice of proposed rulemaking
(NPRM).
AGENCY:
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
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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: https://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
https://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 https://
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 https://
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,
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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. email: Amanda.Prescott@nhtsa.dot.gov.
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:
George.Feygin@nhtsa.dot.gov.
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 nonconvertible 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
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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 rolloverrelated 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.
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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.
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.
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.
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.
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.
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
5 See
56 FR 15510.
64 FR 22567 (April 27, 1999).
7 Examples of these vehicles include model year
1999 Ford Taurus and Dodge Neon.
6 See
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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 realworld 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 realworld 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.
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),
8 See Docket Nos. NHTSA–99–5572–3 & NHTSA–
99–5572–2, respectively at: https://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.
10 See Docket No. NHTSA–2005–22143.
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‘‘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.
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.
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
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
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motor vehicle safety information to
consumers.15
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
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 https://www.nhtsa.dot.gov/
ncap/.
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.
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 one15 See
11 See
66 FR 53376.
12 See 57 FR 242 (January 3, 1992).
13 See Docket Number NHTSA 1999–5572–35.
14 See 59 FR 33254 (June 28, 1994).
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65 FR 34998 at 35001 (June 1, 2000).
65 FR 34998 (June 1, 2000).
17 See 66 FR 3388 (January 12, 2001).
18 See 68 FR 59250.
19 See Docket Number NHTSA 2003–14622–1.
16 See
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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
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
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.
Approximately 273,000 nonconvertible light vehicles were towed
after a police-reported rollover crash
each year. Of these 273,000 light vehicle
rollover crashes, 223,000 were singlevehicle 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.
49227
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
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 nonconvertible 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
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]
Total
occupants
Crash type
Rollover ................................................................................
Frontal Impact ......................................................................
Side Impact ..........................................................................
Rear Impact .........................................................................
467,120
2,786,378
1,218,068
414,711
Fatalities
9,942
12,480
7,932
1,029
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
Accordingly, to refine further the
injury risk estimates more relevant to
this proposal, we examined the rollover
20 See Automotive News World Congress,
‘‘Meeting the Safety Challenge’’ Jeffrey W. Runge,
M.D., Administrator, NHTSA, January 14, 2003,
page 3, 4; (https://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;
(https://www.nhtsa.dot.gov/nhtsa/announce/
testimony/SUVtestimony02–26–03.htm); see also
IPT Rollover Report at https://wwwnrd.nhtsa.dot.gov/vrtc/ca/capubs/
IPTRolloverMitigationReport/ (Page 7).
21 See id. at 8.
22 See IPT Rollover Report at https://wwwnrd.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, https://wwwnrd.nhtsa.dot.gov/pdf/nrd-01/SAE/SAE2004/
EjectMitigate_Duffy.pdf.
24 See IPT Rollover Report at https://wwwnrd.nhtsa.dot.gov/vrtc/ca/capubs/
IPTRolloverMitigationReport/ (Page 12).
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.
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Percent of
occupants
fatally injured
2.1
0.4
0.6
0.2
Fatal and
serious
injuries
Percent of occupants fatally
or seriously
injured
33,735
58,031
29,964
2,338
7.2
2.1
2.5
0.6
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.
26 See
id.
27 Abbreviated
Injury Scale (AIS) 3 to 5.
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.
30 NASS–CDS estimates have been adjusted to
account for cases with unknown or missing data.
31 For younger drivers and rollovers, see William
Deutermann, ‘‘Characteristics of Fatal Rollover
Crashes,’’ DOT HS 809 438, April 2002 (https://
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 (https://wwwnrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/Rpts/2004/
809729.pdf).
28 We
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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]
Crash type
Percent of not fully
ejected occupants fatally
injured (regardless of
belt use)
Percent of not fully
ejected occupants fatally
or seriously injured (regardless of belt use)
Percent of belted occupants fatally injured
(regardless of
ejection status)
Percent of belted occupants fatally or seriously
injured (regardless of
ejection status)
Rollover ............................................
Frontal Impact ..................................
Side Impact ......................................
Rear Impact .....................................
1.1
0.4
0.6
0.2
4.3
2.0
2.3
0.5
0.7
0.3
0.5
0.1
3.5
1.4
1.9
0.3
B. Agency’s Comprehensive Response
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
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.
• 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
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.
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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
Farmer ‘‘Effect of electronic stability control,’’
Traffic Injury Prevention 5:4 (317–25).
33 See https://www.nhtsa.dot.gov/people/injury/
airbags/809713.pdf.
34 Roof damage is measured by the maximum
degree of vertical intrusion into the vehicle by a
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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).
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.
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.
roof component (A-pillar, B-pillar, roof, roof side
rail, windshield header, and backlight header).
35 A quarter turn occurs when the vehicle tips
over from the upright position onto either of its
sides.
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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)]
Maximum vertical roof
intrusion
Passenger cars
(percent)
Light trucks subject to
FMVSS No. 216
(percent)
Light trucks with GVWR
> 2,722 and ≤ 4,536 Kg
(percent)
No Intrusion .................................................................................
3 to 7 cm ......................................................................................
8 to 14 cm ....................................................................................
15 to 29 cm ..................................................................................
30 to 45 cm ..................................................................................
46 cm or more .............................................................................
23,071 (23)
22,219 (22)
22,285 (22)
25,260 (25)
4,810 (5)
2,334 (2)
17,805 (19)
19,264 (20)
12,354 (13)
31,184 (33)
12,225 (13)
2,695 (3)
14,322 (17)
1,499 (6)
5,122 (21)
10,487 (42)
2,107 (8)
1,253 (5)
Total ......................................................................................
Average Amount of Intrusion ................................................
100,075 (100)
82.4 mm
95,586 (100)
111.3 mm
24,791 (100)
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-overend. 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-toground 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
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
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.
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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
37 MAIS injury is the most severe (maximum AIS)
injury for the occupant.
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BILLING CODE 4910–59–C
A. Vehicle Testing
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.
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 fullscale dynamic rollover tests to evaluate
roof integrity and failure modes in
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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.
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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.
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 quasistatic test procedure is simpler and
produces more repeatable results.
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.
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.
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.
40 ‘‘Rollover Roof Crush Studies,’’ Contract
DTNH22–92–D–07323, 1993.
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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
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
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.
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.
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49231
document entitled ‘‘Roof Crush
Research: Load Plate Angle
Determination and Initial Fleet
Evaluation.’’ 43
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.
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
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
43 See
Docket Number NHTSA–2005–22143.
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.
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.
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).
44 2nd
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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 quasistatic 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
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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
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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 chassiscabs, 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
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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
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
51 See
56 FR 15510 (April 17, 1991).
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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 passengercarrying vehicles not subject to the
requirements of FMVSS No. 216 is
increasing every year.
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
52 https://www.polk.com/products/
new_vehicle_data.asp.
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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.
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.
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.
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.
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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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.
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.
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
58 ‘‘Design
Modification for a 1989 Nissan Pickup—Final Report,’’ DOT HS 807 925, NTIS,
Springfield, Virginia, 1991.
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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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 multistage, 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
The agency traditionally took this
approach because the agency
historically was of the view that it could
not subject vehicles built in multiplestages 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.
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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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 multistage 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
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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 multistage 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 nonchassis-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
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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 multistage 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
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.
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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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.
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
64 5,000
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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.
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.
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 quasistatic 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
65 Table 3 shows the percent of roof-involved
rollover vehicles with particular degrees of vertical
roof intrusion by vehicle body type.
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.
67 Glen C. Rains and Mike Van Voorhis, ‘‘Quasi
Static and Dynamic Roof Crush Testing,’’ DOT HS
808–873, 1998.
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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.
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
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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.
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
68 See
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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.
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
69 https://www.nhtsa.dot.gov/cars/rules/CAFE/
NewPassengerCarFleet.htm.
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Docket Number NHTSA–2005–22143.
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49237
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.
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 postcrash headroom above the top of their
head experienced roof contact injuries
to the head, neck, or face, compared to
34 percent for occupants with postcrash headroom below the top of their
head. Using CU vehicle headroom
measurement parameters, we estimate
that 10 percent of occupants with postcrash headroom above the top of their
head experienced roof contact injuries
to the head, neck, or face, compared to
32 percent for occupants with postcrash 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
71 Ford
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appropriate for low roofline vehicles in
order to make the standard practicable.
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 ViewTM glasspaneled 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 Dpillar on station wagons, SUVs or
minivans; and (3) the horizontal and
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vertical axes at the center of the roof
side, usually about the top of the Bpillar. CU and several individual
commenters recommended that a more
representative plate angle should be 45degrees 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 realworld 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 Bpillars, 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.
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
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
Docket Number NHTSA–1999–5572–95.
J. Leigh and Donald T. Willke,
‘‘Upgraded Rollover Roof Crush Protection:
Rollover Test and NASS Case Analysis,’’ Docket
NHTSA–1996–1742–18, June 1992.
74 See Docket No. NHTSA–2005–22143.
75 ‘‘Roof Crush Research: Load Plate Angle
Determination and Initial Fleet Evaluation.’’ Docket
No. NHTSA–2005–22143.
PO 00000
72 See
73 Michael
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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.
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
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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.
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.
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
In summary, the first and second side
force deflection curves track similarly
for the Pacifica and Quest. For the
id.
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.
79 See Docket Number NHTSA–2005–22143.
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.
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
76 See
77 Near
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80 ‘‘Roof Crush Research: Load Plate Angle
Determination and Initial Fleet Evaluation.’’ Docket
No. NHTSA–2005–22143.
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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49239
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.
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, nonejected 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
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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 realworld 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 frontend 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
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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.
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
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.
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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 nonrigid 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
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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.
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
85 See
86 See
Docket Number 94–097–N02–010.
Docket No. 2005–22143.
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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.
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 quasistatic testing adequately represent real
world dynamic deformation patterns
occurring in rollovers.
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
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.
88 Docket No. NHTSA–99–5572–2 (https://
dmses.dot.gov/docimages/pdf37/57806_web.pdf).
89 Docket No. NHTSA–99–5572–3 (https://
dmses.dot.gov/docimages/pdf39/62547_web.pdf).
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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 nondistributed loading near the edge plate
contact when the secondary plate
position was used.
As discussed in Section VII(C)(4), the
agency is proposing to eliminate the
secondary test procedure (49 CFR
§ 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 rolloverrelated 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
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
90 See https://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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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 prerollover 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 3point 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
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
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.
96 See Docket Number NHTSA 2003–14622–10.
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pretensioning systems, electric
retractors, inflatable seat belts, and fourpoint harnesses.
Since advanced restraints have the
potential for contributing to the
comprehensive effort to reduce rolloverrelated 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
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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.
97 Negative headroom means post-crash
headroom that is below the occupant’s seated
height.
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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.
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
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force of about 20 percent greater than
2.5 times their vehicle weight.98
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
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 × $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
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 × 2.5).
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.
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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
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
https://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
101 For details on the fuel economy impacts,
please see the PRIA.
102 See 49 CFR 553.21.
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copy certain portions of your
submissions.103
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 https://www.whitehouse.gov/
omb/fedreg/reproducible.html. DOT’s
guidelines may be accessed at https://
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
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
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.
104 See 49 CFR Part 512.
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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
(https://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.
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
PO 00000
105 See
Docket No. NHTSA–2005–22143.
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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
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.
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
106 As discussed in Section X above, 68% of the
current fleet meets the proposed requirements.
107 Avanti, Panoz, Saleen, Shelby.
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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
3. We believe that some of the
vehicles manufactured by these small
businesses already comply with the
proposed requirements.109
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
108 Approximately
$25,000.
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.
109 As
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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
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49245
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
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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.
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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
XVI. Vehicle Safety Act
costs and benefits of our proposal. In
sum, this document reflects our
Under 49 U.S.C. Chapter 301, Motor
Vehicle Safety (49 U.S.C. 30101 et seq.), consideration of all relevant, available
motor vehicle safety information.
the Secretary of Transportation is
Fourth, to ensure that requiring
responsible for prescribing motor
greater roof crush resistance is
vehicle safety standards that are
practicable, the agency tested a number
practicable, meet the need for motor
of vehicles and found that many already
vehicle safety, and are stated in
objective terms.110 ‘‘Motor vehicle safety comply with the proposed
requirements, while others could
standard’’ means a minimum
performance standard for motor vehicles comply with relatively inexpensive
modifications to their roof structure. In
or motor vehicle equipment. When
response to the request for comments,
prescribing such standards, the
the agency received no indication that
Secretary must consider all relevant,
the proposed roof crush resistance
available motor vehicle safety
information.111 The Secretary must also requirements were impracticable.
consider whether a proposed standard is However, based on the latest
reasonable, practicable, and appropriate information from the manufacturers and
our own testing, we are proposing to
for the types of motor vehicles or motor
amend the test procedure for vehicles
vehicle equipment for which it is
with raised or altered roofs to provide
prescribed and the extent to which the
additional assurance of practicability.113
standard will further the statutory
To improve practicability still further,
purpose of reducing traffic accidents
the agency also proposes to revise the
and associated deaths.112 The
tie-down procedure. Because we are
responsibility for promulgation of
especially concerned with practicability
Federal motor vehicle safety standards
of this proposal as it applies to vehicles
is delegated to NHTSA.
In proposing to improve roof crush
manufactured in two or more stages, we
resistance, the agency carefully
are proposing to allow the certification
considered these statutory requirements. of these vehicles to the roof crush
First, we believe that this proposal
requirements of FMVSS No. 220. In
will meet the need for motor vehicle
sum, we believe that this proposal to
safety because the proposed applied
improve roof crush resistance is
force requirement would lead to
practicable.
stronger roofs and reduce the roof crush
Fifth, the proposed regulatory text
severity observed in real world crashes,
following this preamble is stated in
thus better protecting front seat
objective terms in order to specify
occupants.
precisely what performance is required
Second, we believe that the roof crush and how performance will be tested to
resistance standard subject of this
ensure compliance with the standard.
proposal is performance oriented
Specifically, a large steel test plate
because it requires only that the vehicle would be forced down onto the roof of
roof be able to withstand a certain
a vehicle. If the displaced roof structure
amount of applied force. The standard
does not contact the head or neck of the
does not specify the means by which the dummy seated inside the vehicle, the
vehicle must meet the standard.
vehicle passes the test. The agency
Third, this proposal was preceded by
believes that this test procedure is
a Request for Comments, which
sufficiently objective and would not
facilitated the efforts of the agency to
result in any uncertainty as to whether
obtain and consider relevant motor
a given vehicle satisfies the proposed
vehicle safety information. We
roof crush resistance requirements.
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 https://dms.dot.gov.
PO 00000
110 49
111 49
U.S.C. 30111(a).
U.S.C. 30111(b).
113 The agency previously adopted a ‘‘secondary’’
test procedure for vehicles with raised or altered
roofs which proved to be an impracticable solution.
112 Id.
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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:
§ 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 (§ 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
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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
(§ 571.220).
S4. Definitions.
*
*
*
*
*
Convertible means a vehicle whose Apillars 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 nonstructural components.
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(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.
*
*
*
*
*
For legal issues: Dorothy Nakama,
Office of the Chief Counsel, NCC–112,
National Highway Traffic Safety
Administration, 400 Seventh Street,
SW., Washington, DC 20590. Telephone:
(202) 366–2992. Fax: (202) 366–3820.
SUPPLEMENTARY INFORMATION:
Issued: July 15, 2005.
Stephen R. Kratzke,
Associate Administrator for Rulemaking.
[FR Doc. 05–16661 Filed 8–19–05; 8:45 am]
Table of Contents
I. Background
II. Summary of Request for Comments
III. Analysis of Comments
IV. Rationale for Withdrawal
V. Conclusion
BILLING CODE 4910–59–U
I. Background
DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety
Administration
49 CFR Parts 571 and 572
[Docket No. NHTSA–2005–21698]
RIN 2127–AH73 and 2127–AI39
Federal Motor Vehicle Safety
Standards; Occupant Crash
Protection; Anthropomorphic Test
Devices; Instrumented Lower Legs for
50th Percentile Male and 5th Percentile
Female Hybrid III Dummies
National Highway Traffic
Safety Administration (NHTSA), DOT.
ACTION: Withdrawal of rulemakings.
AGENCY:
SUMMARY: On February 3, 2004, NHTSA
published a notice in the Federal
Register requesting comments on
whether to propose adding a high speed
frontal offset crash test to Federal Motor
Vehicle Safety Standard (FMVSS) No.
208, ‘‘Occupant crash protection.’’ The
notice informed the public about recent
testing the agency conducted to assess
the benefits and/or disbenefits of such
an approach. Based on our analysis of
those comments, and other information
gathered by the agency, we have
decided to withdraw the rulemaking
proceeding to amend FMVSS No. 208 to
include a high speed frontal offset crash
test requirement. Additional research
and data analyses are needed to make an
informed decision on rulemaking in this
area. Additionally, we have decided to
withdraw the related rulemaking
proceeding to amend part 572 to include
lower leg instrumentation until further
testing necessary for federalization is
completed.
FOR FURTHER INFORMATION CONTACT: For
non-legal issues: Lori Summers, Office
of Crashworthiness Standards, NVS–
112, National Highway Traffic Safety
Administration, 400 Seventh Street,
SW., Washington, DC 20590. Telephone
(202) 366–1740. Fax: (202) 366–7002.
VerDate jul<14>2003
16:15 Aug 22, 2005
Jkt 205001
Improving occupant protection in
frontal crashes is a major goal of the
National Highway Traffic Safety
Administration (NHTSA). Frontal
crashes are the most frequent cause of
motor vehicle fatalities. In 1972,
NHTSA promulgated FMVSS No. 208 to
improve the frontal crash protection
provided to motor vehicle occupants.
The dynamic performance requirements
of the standard include frontal rigid
barrier crash tests, at angles between
perpendicular and ±30 degrees with
belted and unbelted dummies.1
Occupant protection is evaluated based
on data acquired from anthropomorphic
test dummies positioned in the driver
and right front passenger seats. Data
collection instrumentation is mounted
in the head, neck, chest, and femurs of
the test dummies.
NHTSA initiated research in the early
1990s to develop performance tests not
currently included in FMVSS No. 208,
such as high severity frontal offset
crashes that involve only partial
engagement of a vehicle’s front
structure. Such performance tests result
in large amounts of occupant
compartment intrusion and increased
potential for intrusion-related injury.
The agency also instrumented the
dummies in these tests with advanced
lower leg instrumentation, not currently
required in FMVSS No. 208, to assess
the potential for lower extremity injury,
specifically, to the knee, tibia, and
ankle.
During the same time period,
considerable international research
focused on the development of a fixed
offset deformable barrier crash test
procedure. In December 1996, the
European Union (EU) adopted the EU
Directive 96/79 EC for frontal crash
protection. This directive required
vehicle compliance with a 56 km/h, 40
March of 1997, NHTSA temporarily amended
FMVSS No. 208 so that passenger cars and light
trucks had the option of using a sled test for
meeting the unrestrained dummy requirements.
This option will be phased out in accordance with
the advanced air bag rulemaking schedule.
PO 00000
1 In
Frm 00049
Fmt 4702
Sfmt 4702
percent offset, fixed deformable barrier
crash test. In 1998, Australia introduced
a similar regulation for new passenger
car model approvals. In addition to
these regulations, several consumer
information programs also began to
utilize the EU Directive 96/79 EC crash
test procedure, but raised the impact
speed to 64 km/h. These programs
included the European New Car
Assessment Program (EuroNCAP),
Australia NCAP (ANCAP), Japan NCAP
and the Insurance Institute for Highway
Safety (IIHS) Crashworthiness
Evaluation program in the U.S.
Given the world-wide focus on the
fixed offset deformable barrier crash test
procedure, the conferees on the
appropriations legislation for the
Department of Transportation for FY
1997 directed NHTSA to work ‘‘toward
establishing a Federal motor vehicle
safety standard for frontal offset crash
testing’’ in fiscal year 1997.2 NHTSA
was further directed to consider the
harmonization potential with other
countries and to work with interested
parties, including the automotive
industry, under standard rulemaking
procedures. In 1997, NHTSA submitted
a Report to Congress 3 on the status of
the agency’s efforts toward establishing
a high speed frontal offset crash test
requirement. The agency made a
preliminary assessment that the
adoption of the EU 96/79 EC frontal
offset test procedure, in addition to the
current requirements of FMVSS No.
208, could result in substantial benefits,
since lower leg injuries were typically
associated with long-term recovery and
significant economic cost. However, the
Report to Congress also made note of
NHTSA’s concerns relative to the
potential for exacerbating small and
large car incompatibility, as a result of
adopting a frontal offset crash test
procedure.
During 1998–2002, NHTSA
completed over 25 frontal offset crash
tests in an attempt to answer a number
of research questions. Specifically, what
are the merits of a fixed offset
deformable barrier crash test procedure
and what is the most appropriate
dummy size, lower leg instrumentation
and impact speed? Dummy injury
measures from the fixed offset
deformable barrier crash tests
demonstrated the potential for injury
reductions over and above the full
frontal rigid barrier test configuration.4
2 Conference Report 104–785, September 16,
1996. This report accompanied H.R. 3675.
3 Report to Congress, ‘‘Status Report on
Establishing a Federal Motor Vehicle Safety
Standard for Frontal Offset Crash Testing,’’ April
1997.
4 Docket No. NHTSA–1998–3332.
E:\FR\FM\23AUP1.SGM
23AUP1
Agencies
[Federal Register Volume 70, Number 162 (Tuesday, August 23, 2005)]
[Proposed Rules]
[Pages 49223-49248]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-16661]
=======================================================================
-----------------------------------------------------------------------
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).
-----------------------------------------------------------------------
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: https://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 https://
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 https://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 https://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:
Amanda.Prescott@nhtsa.dot.gov.
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:
George.Feygin@nhtsa.dot.gov.
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.
---------------------------------------------------------------------------
\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.
---------------------------------------------------------------------------
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.
---------------------------------------------------------------------------
\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.
---------------------------------------------------------------------------
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.
---------------------------------------------------------------------------
\5\ See 56 FR 15510.
---------------------------------------------------------------------------
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.
---------------------------------------------------------------------------
\6\ See 64 FR 22567 (April 27, 1999).
\7\ Examples of these vehicles include model year 1999 Ford
Taurus and Dodge Neon.
---------------------------------------------------------------------------
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.
---------------------------------------------------------------------------
\8\ See Docket Nos. NHTSA-99-5572-3 & NHTSA-99-5572-2,
respectively at: https://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.
---------------------------------------------------------------------------
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.
---------------------------------------------------------------------------
\10\ See Docket No. NHTSA-2005-22143.
---------------------------------------------------------------------------
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.
---------------------------------------------------------------------------
\11\ See 66 FR 53376.
---------------------------------------------------------------------------
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\
---------------------------------------------------------------------------
\12\ See 57 FR 242 (January 3, 1992).
\13\ See Docket Number NHTSA 1999-5572-35.
---------------------------------------------------------------------------
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\
---------------------------------------------------------------------------
\14\ See 59 FR 33254 (June 28, 1994).
\15\ See 65 FR 34998 at 35001 (June 1, 2000).
---------------------------------------------------------------------------
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\
---------------------------------------------------------------------------
\16\ See 65 FR 34998 (June 1, 2000).
\17\ See 66 FR 3388 (January 12, 2001).
---------------------------------------------------------------------------
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 https://
www.nhtsa.dot.gov/ncap/.
---------------------------------------------------------------------------
\18\ See 68 FR 59250.
---------------------------------------------------------------------------
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.
---------------------------------------------------------------------------
\19\ See Docket Number NHTSA 2003-14622-1.
---------------------------------------------------------------------------
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\
---------------------------------------------------------------------------
\20\ See Automotive News World Congress, ``Meeting the Safety
Challenge'' Jeffrey W. Runge, M.D., Administrator, NHTSA, January
14, 2003, page 3, 4; (https://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; (https://www.nhtsa.dot.gov/nhtsa/announce/
testimony/SUVtestimony02-26-03.htm); see also IPT Rollover Report at
https://www-nrd.nhtsa.dot.gov/vrtc/ca/capubs/
IPTRolloverMitigationReport/ (Page 7).
---------------------------------------------------------------------------
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\
---------------------------------------------------------------------------
\21\ See id. at 8.
---------------------------------------------------------------------------
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.
---------------------------------------------------------------------------
\22\ See IPT Rollover Report at https://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, https://www-nrd.nhtsa.dot.gov/pdf/
nrd-01/SAE/SAE2004/EjectMitigate_Duffy.pdf.
\24\ See IPT Rollover Report at https://www-nrd.nhtsa.dot.gov/
vrtc/ca/capubs/IPTRolloverMitigationReport/ (Page 12).
---------------------------------------------------------------------------
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.
---------------------------------------------------------------------------
\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.
---------------------------------------------------------------------------
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\
---------------------------------------------------------------------------
\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.
---------------------------------------------------------------------------
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\
---------------------------------------------------------------------------
\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]
----------------------------------------------------------------------------------------------------------------
Percent of
Percent of Fatal and occupants
Crash type Total Fatalities occupants serious fatally or
occupants fatally injuries seriously
injured injured
----------------------------------------------------------------------------------------------------------------
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
----------------------------------------------------------------------------------------------------------------
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\
---------------------------------------------------------------------------
\31\ For younger drivers and rollovers, see William Deutermann,
``Characteristics of Fatal Rollover Crashes,'' DOT HS 809 438, April
2002 (https://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
(https://www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/Rpts/2004/809729.pdf).
---------------------------------------------------------------------------
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]
--------------------------------------------------------------------------------------------------------------------------------------------------------
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)
--------------------------------------------------------------------------------------------------------------------------------------------------------
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
--------------------------------------------------------------------------------------------------------------------------------------------------------
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.
---------------------------------------------------------------------------
\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 https://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\
---------------------------------------------------------------------------
\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\
---------------------------------------------------------------------------
\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\
---------------------------------------------------------------------------
\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).
---------------------------------------------------------------------------
[[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 ro