[Federal Register Volume 70, Number 162 (Tuesday, August 23, 2005)]
[Proposed Rules]
[Pages 49223-49248]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-16661]


=======================================================================
-----------------------------------------------------------------------

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: http://dms.dot.gov. Follow the instructions for 
submitting comments on the DOT electronic docket site.
     Fax: 1-202-493-2251.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-001.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 am 
and 5 pm, Monday through Friday, except Federal holidays.
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the online instructions for submitting 
comments.
    Instructions: All submissions must include the agency name and 
docket number or Regulatory Identification Number (RIN) for this 
rulemaking. Note that all comments received will be posted without 
change to http://dms.dot.gov including any personal information 
provided. Please see the Privacy Act heading under Regulatory Notices.
    Docket: For access to the docket to read background documents or 
comments received, go to http://dms.dot.gov at any time or to Room PL-
401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., 
Washington, DC, between 9 am and 5 pm, Monday through Friday, except 
Federal holidays.

FOR FURTHER INFORMATION CONTACT: For technical issues: Ms. Amanda 
Prescott, Office of Vehicle Safety Compliance, NVS-224, National 
Highway Traffic Safety Administration, 400 7th Street, SW., Washington, 
DC 20590. Telephone: (202) 366-5359. Fax: (202) 366-3081. e-mail: 
[email protected].
    For legal issues: Mr. George Feygin, Attorney Advisor, Office of 
the Chief Counsel, NCC-112, National Highway Traffic Safety 
Administration, 400 7th Street, SW., Washington, DC 20590. Telephone: 
(202) 366-5834. Fax: (202) 366-3820. E-mail: 
[email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary and Overview
II. Background
    A. Current Performance Requirements
    B. Previous Rulemaking, Petitions, and October 2001 Request for 
Comments Concerning Performance Requirements
    1. Extension of Roof Crush Standard to Light Trucks
    2. Plate Positioning Procedure
    3. Upgrade of Performance Requirements
    C. Consumer Information on Rollover Resistance
    D. Development of Comprehensive Plan
III. Overall Rollover Problem and the Agency's Comprehensive 
Response
    A. Overall Rollover Problem
    B. Agency's Comprehensive Response
IV. The Role of Roof Intrusion in the Rollover Problem
    A. Rollover Induced Vertical Roof Intrusion
    B. Occupant Injuries in Rollover Crashes Resulting in Roof 
Intrusion
V. Previous Rollover and Roof Crush Mitigation Research
    A. Vehicle Testing
    B. Analytical Research
    C. Latest Agency Testing and Analysis
    1. Vehicle Testing
    2. Revised Tie-Down Testing
VI. Summary of Comments in Response to the October 2001 Request for 
Comments
VII. Agency Proposal
    A. Proposed Application
    1. MPVs, Trucks and Buses with a GVWR of 4,536 Kilograms (10,000 
pounds) or Less
    2. Vehicles Manufactured in Two or More Stages
    3. Convertibles
    B. Proposed Amendments to the Roof Strength Requirements
    1. Increased Force Requirement
    2. Headroom Requirement
    C. Proposed Amendments to the Test Procedures
    1. Retaining the Current Test Procedure
    2. Dynamic Testing
    3. Revised Tie-Down Procedure
    4. Plate Positioning Procedure
VIII. Other Issues
    A. Agency Response to Hogan Petition
    B. Agency Response to Ford and RVIA Petition
    C. Request for Comments on Advanced Restraints
IX. Benefits
X. Costs
XI. Lead Time
XII. Request for Comments
XIII. Rulemaking Analyses and Notices
    A. Executive Order 12866 and DOT Regulatory Policies and 
Procedures
    B. Regulatory Flexibility Act
    C. National Environmental Policy Act
    D. Executive Order 13132 (Federalism)
    E. Unfunded Mandates Act
    F. Civil Justice Reform
    G. National Technology Transfer and Advancement Act
    H. Paperwork Reduction Act
    I. Plain Language
    J. Privacy Act
XIV. Vehicle Safety Act
XV. Proposed Regulatory Text

I. Executive Summary and Overview

    As part of a comprehensive plan for reducing the risk of death and 
serious injury from rollover crashes, this notice proposes to upgrade 
Federal Motor Vehicle Safety Standard (FMVSS) No. 216, Roof Crush 
Resistance. This standard, which seeks to reduce deaths and serious 
injuries resulting from crushing of the roof into the occupant 
compartment as a result of ground contact during rollover crashes, 
currently applies to passenger cars, and to multipurpose passenger 
vehicles, trucks and buses with a GVWR of 2,722 kilograms (6,000 
pounds) or less. The standard requires that when a large steel test 
plate is forced down onto the roof of a vehicle, simulating contact 
with the ground in rollover crashes, the vehicle roof structure must 
withstand a force equivalent to 1.5 times the unloaded weight of the 
vehicle, without the test plate moving more than 127 mm (5 inches). 
Under S5 of the standard, the application of force is limited to 22,240 
Newtons (5,000 pounds) for passenger cars.
    Recent agency data show that nearly 24,000 occupants are seriously 
injured and 10,000 occupants are fatally injured in approximately 
273,000 non-convertible light vehicle rollover crashes that occur each 
year. In order to identify how many of these occupants might benefit 
from this proposal, the agency analyzed real-world injury data in order 
to determine the number of occupant injuries that could be attributed 
to roof intrusion. The agency examined only front outboard occupants 
who were belted, not fully ejected from their vehicles, whose most 
severe injury was associated with roof contact, and whose seating 
position was located below a roof component that experienced vertical 
intrusion as a result of a rollover crash. NHTSA estimates that there 
are about 807 seriously and approximately 596 fatally injured occupants 
that fit these criteria. The agency believes that some of these

[[Page 49225]]

occupants would benefit from this proposal.
    To better address fatalities and injuries occurring in roof-
involved rollover crashes, we are proposing to extend the application 
of the standard to vehicles with a GVWR of up to 4,536 kilograms 
(10,000 pounds), and to strengthen the requirements of FMVSS No. 216 by 
mandating that the vehicle roof structures withstand a force equivalent 
to 2.5 times the unloaded vehicle weight, and eliminating the 22,240 
Newtons (5,000 pounds) force limit for passenger cars. Further, we are 
proposing a new direct limit on headroom reduction, which would replace 
the current limit of test plate movement. This new limit would prohibit 
any roof component from contacting a seated 50th percentile male dummy 
under the application of a force equivalent to 2.5 times the unloaded 
vehicle weight. For vehicles built in two or more stages, the agency is 
proposing an option of certifying to the roof crush requirements of 
FMVSS No. 220, ``School bus rollover protection,'' instead of FMVSS No. 
216. Finally, in response to several petitions, we reexamined the 
current testing procedures and are proposing certain modifications to 
the vehicle tie-down procedure and test plate positioning for raised or 
altered roof vehicles.
    Consistent with the agency's continuing effort to reduce rollover-
related injuries and fatalities, this document requests additional 
comments on certain other countermeasures that could further this 
initiative. Specifically, we ask for comments related to seat belt 
pretensioners that could limit vertical head excursion in a rollover 
event.
    The agency used two alternative methods to estimate the benefits of 
this proposal. Under the first alternative, we estimate that this 
proposal would prevent 793 non-fatal injuries and 13 fatalities. Under 
the second alternative, we estimate that this proposal would prevent 
498 non-fatal injuries and 44 fatalities. The annual equivalent lives 
saved are estimated at 39 and 55, respectively.
    The estimated average cost in 2003 dollars, per vehicle, of meeting 
the proposed requirements would be $10.67 per affected vehicle. Added 
weight from design changes is estimated to increase lifetime fuel costs 
by $5.33 to $6.69 per vehicle. The cost per year for the vehicle fleet 
is estimated to be $88-$95 million. The cost per equivalent life saved 
is estimated to range from $2.1 to $3.4 million.

II. Background

A. Current Performance Requirements

    FMVSS No. 216 currently applies to passenger cars, multipurpose 
passenger vehicles (MPVs), trucks, and buses \1\ with a GVWR of 2,722 
kilograms (6,000 pounds) or less. The standard requires that the ``roof 
over the front seat area'' \2\ must withstand a force equivalent to 1.5 
times the unloaded weight of the vehicle. For passenger cars, this 
force is limited to a maximum of 22,240 N (5,000 pounds). Specifically, 
the vehicle's roof must prevent the test plate from moving more than 
127 mm (5 inches) in the specified test.
---------------------------------------------------------------------------

    \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: http://dms.dot.gov/search/searchFormSimple.cfm.
    \9\ On January 31, 2000, the agency published a partial response 
to petitions delaying application of the new secondary plate 
positioning testing procedure until October 25, 2000. See 65 FR 
4579.
---------------------------------------------------------------------------

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 http://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; (http://www.nhtsa.dot.gov/nhtsa/announce/speeches/030114Runge/AutomotiveNewsFinal.pdf); see also The 
Honorable Jeffrey W. Runge, M.D., Administrator, NHTSA, before the 
Committee on Commerce, Science, and Transportation. U.S. Senate, 
February 26, 2003; (http://www.nhtsa.dot.gov/nhtsa/announce/testimony/SUVtestimony02-26-03.htm); see also IPT Rollover Report at 
http://www-nrd.nhtsa.dot.gov/vrtc/ca/capubs/IPTRolloverMitigationReport/ (Page 7).
---------------------------------------------------------------------------

    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 http://www-nrd.nhtsa.dot.gov/vrtc/ca/capubs/IPTRolloverMitigationReport/ (Page 5).
    \23\ Status of NHTSA's Ejection Mitigation Research, J. Stephen 
Duffy, Transportation Research Center, Inc., SAE Government/Industry 
Meeting, May 10, 2004, slide 2, http://www-nrd.nhtsa.dot.gov/pdf/nrd-01/SAE/SAE2004/EjectMitigate_Duffy.pdf.
    \24\ See IPT Rollover Report at http://www-nrd.nhtsa.dot.gov/vrtc/ca/capubs/IPTRolloverMitigationReport/ (Page 12).
---------------------------------------------------------------------------

    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 (http://www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/Rpts/2002/809-438.pdf). For younger occupants and seat belt use, see Donna 
Glassbrenner, ``Safety Belt Use in 2003,'' DOT HS 809 729, May 2004 
(http://www-nrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/Rpts/2004/809729.pdf).
---------------------------------------------------------------------------

    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 http://www.nhtsa.dot.gov/people/injury/airbags/809713.pdf.
---------------------------------------------------------------------------

    All of these countermeasures must work together to help create a 
driving environment in which rollovers can be avoided and rollover-
related fatalities and injuries minimized. States legislatures, the 
enforcement community (including police officers, prosecutors and 
judges), vehicle makers and their suppliers and the driving public all 
play critical parts in eliminating the 10,000 rollover-related 
fatalities suffered each year. Government also plays a role in ensuring 
that safety requirements are mandated when the benefits of doing so are 
established. This proposal to upgrade our roof crush standard is only 
one such effort by the agency to address the rollover hazard.

IV. The Role of Roof Intrusion in the Rollover Problem

A. Rollover Induced Vertical Roof Intrusion

    The agency has examined data on vehicle rollovers resulting in roof 
damage.\34\ This information was derived from NASS-CDS (1997 to 2002). 
Vertical roof intrusion is recorded in NASS-CDS when it exceeds 2 cm 
(0.8 inches).
---------------------------------------------------------------------------

    \34\ Roof damage is measured by the maximum degree of vertical 
intrusion into the vehicle by a roof component (A-pillar, B-pillar, 
roof, roof side rail, windshield header, and backlight header).
---------------------------------------------------------------------------

    Using the NASS-CDS data from 1997 to 2002, we conclude that out of 
the total of 272,925 light duty vehicle rollovers in towaway crashes, 
220,452 rolled more than one-quarter turn.\35\ The 52,473 vehicles that 
experienced only a one-quarter turn were excluded from the analysis 
because one-quarter turn rollovers usually do not result in vertical 
roof intrusion since they do not experience roof-to-ground contact. We 
found that out of the 220,452 vehicles that rolled more than one-
quarter turn, 175,253 experienced vertical intrusion of some roof 
component. We estimate that in 82 percent (142,954) of these cases, the 
most severe roof intrusion occurred over the front seat positions. 
Approximately 92 percent of the fatally or seriously injured belted 
occupants who were not fully ejected were in front seats.
---------------------------------------------------------------------------

    \35\ A quarter turn occurs when the vehicle tips over from the 
upright position onto either of its sides.
---------------------------------------------------------------------------

    In addition, NHTSA examined how vertical roof intrusion relates to 
a vehicle's body type and GVWR. We compared passenger cars, light 
trucks currently subject to the standard, and light trucks with a GVWR 
greater than 2,722 kilograms (6,000 pounds) but less than or equal to 
4,536 kilograms (10,000 pounds). The estimates in Table 3 show that 
light trucks not subject to the current standard experienced patterns 
of roof intrusion which were slightly greater than vehicles already 
subject to the requirements of FMVSS No. 216. Further, the heavier 
vehicles above 2,722 kilograms (6,000 pounds) experienced a greater 
maximum vertical roof intrusion.

[[Page 49229]]



  Table 3.--Percent of Vehicles Involved in Rollover Crashes (More Than One Quarter-Turn) by Degree of Vertical
                                                 Roof Intrusion
                  [1997-2002 NASS-CDS and 2002 Polk National Vehicle Population Profile (NVPP)]
----------------------------------------------------------------------------------------------------------------
                                                                                          Light trucks with GVWR
   Maximum vertical roof  intrusion         Passenger cars      Light trucks subject to  > 2,722 and <= 4,536 Kg
                                              (percent)         FMVSS No. 216 (percent)          (percent)
----------------------------------------------------------------------------------------------------------------
No Intrusion.........................              23,071 (23)              17,805 (19)              14,322 (17)
3 to 7 cm............................              22,219 (22)              19,264 (20)                1,499 (6)
8 to 14 cm...........................              22,285 (22)              12,354 (13)               5,122 (21)
15 to 29 cm..........................              25,260 (25)              31,184 (33)              10,487 (42)
30 to 45 cm..........................                4,810 (5)              12,225 (13)                2,107 (8)
46 cm or more........................                2,334 (2)                2,695 (3)                1,253 (5)
                                      --------------------------
    Total............................            100,075 (100)             95,586 (100)             24,791 (100)
    Average Amount of Intrusion......                  82.4 mm                 111.3 mm                 150.5 mm
                                      ==========================
    Total Number of Vehicles.........                                   220,452
----------------------------------------------------------------------------------------------------------------

B. Occupant Injuries in Rollover Crashes Resulting in Roof Intrusion

    In addition to examining the risk of injuries associated with 
rollover events, and the prevalence of roof intrusions resulting from 
rollover, the agency examined actual occupant injuries and fatalities 
resulting from roof intrusions that occurred after the vehicle rolled 
more than one-quarter turn or end-over-end. Some occupants sustaining 
these injuries could potentially benefit from upgrading the roof crush 
resistance requirements.
    Again, the agency limited this injury analysis to belted occupants 
who were not fully ejected from their vehicles. In order to determine 
the number of occupant injuries that could be attributed to roof 
intrusion, the injury data were further limited to only front outboard 
occupants.\36\ Further, NHTSA excluded rollover crashes producing roof 
intrusion as a result of a collision with a fixed object such as a tree 
or a pole. Using NASS-CDS (1997--2002) data, NHTSA estimates that 4 
percent of vehicles involved in rollovers collided with fixed objects 
in a way that caused roof damage. The agency excluded these vehicles in 
assessing potential benefits of this proposal because we found that 
roof damage observed from fixed object collisions was often 
catastrophic in nature and exhibited different deformation patterns 
than roof-to-ground impacts due to the localization of the force. The 
agency believes that this proposal is not likely to have appreciable 
benefits for these types of collisions. Finally, the occupant MAIS 
injury must have resulted from contact with a roof component.\37\
---------------------------------------------------------------------------

    \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 rollover 
crashes. Specifically, NHTSA is proposing to:
     Extend the application of the standard to MPVs, trucks, 
and buses with a GVWR greater than 2,722 kilograms (6,000 pounds), but 
not greater than 4,536 kilograms (10,000 pounds).
     Allow vehicles manufactured in two or more stages, other 
than chassis-cabs, to be certified to the roof crush requirements of 
FMVSS No. 220, instead of FMVSS No. 216.
     Clarify the definition and scope of exclusion for 
convertibles.
     Require that vehicles subject to the standard withstand 
the force of 2.5 times their unloaded vehicle weight.
     Eliminate the 22,240 Newton maximum force limit for 
passenger cars.
     Replace the current plate movement limit with a new direct 
limit on headroom reduction, which would prohibit any roof component or 
the test plate from contacting the 50th percentile male Hybrid III 
dummy seated in either front outboard designated seating position.
     Revise the vehicle tie-down procedure to minimize 
variability in testing.
     Revise the test device positioning to minimize variability 
in testing.

A. Proposed Application

1. MPVs, Trucks and Buses with a GVWR of 4,536 Kilograms (10,000 
pounds) or Less
    Currently, FMVSS No. 216 applies to passenger cars and to MPVs, 
trucks and buses with a GVWR of 2,722 kilograms (6,000 pounds) or less. 
However, it does

[[Page 49233]]

not apply to school buses, convertibles, and vehicles that conform to 
the rollover test requirements in S5.3 of FMVSS No. 208.
    As discussed in Section II(B), the agency amended FMVSS No. 216 on 
April 17, 1991 by extending application of the standard to include 
MPVs, trucks, and buses with a GVWR of 2,722 kilograms (6,000 pounds) 
or less. The agency sought to ensure that those vehicles offered a 
level of roof crush protection comparable to that offered by passenger 
cars.
    Prior to the 1991 final rule, NHTSA proposed to extend the 
application of the standard up to the GVWR of 4,536 kilograms (10,000 
pounds) or less. However, because of concerns regarding the feasibility 
of this proposal, the agency adopted a more limited extension and 
indicated it would investigate this issue further before conducting 
further rulemaking.\51\
---------------------------------------------------------------------------

    \51\ See 56 FR 15510 (April 17, 1991).
---------------------------------------------------------------------------

    As previously discussed in Section IV(A), recent data indicate that 
a significant number of serious and fatal injuries occur during 
rollovers of light trucks with a GVWR between 2,722 kilograms (6,000 
pounds) and 4,536 kilograms (10,000 pounds). Based on these injury data 
and the responses to the October 2001 RFC, the agency is once again 
proposing to extend the application of the standard to include light 
trucks with a GVWR up to 4,536 kilograms (10,000 pounds).
    In comments on the October 2001 RFC, the Alliance, DC, GM, and 
Biomech all stated that there are little or no data to support 
extending the application of the standard to 4,536 kilograms (10,000 
pounds). In contrast, CU, Public Citizen, and several individual 
commenters stated that the weight limit should be raised up to 4,536 
kilograms (10,000 pounds) GVWR due to widespread use of sports utility 
vehicles for family transportation and their concerns regarding 
rollover risks associated with 15-passenger vans.
    A significant percentage of light trucks are not yet subject to the 
requirements of FMVSS No. 216. Specifically, Polk New Vehicle 
Registration data show that out of a total of 8,800,000 new light 
trucks registered in 2003, more than 44 percent (3,900,000) had a GVWR 
between 2,722 kilograms (6,000 pounds) and 4,536 kilograms (10,000 
pounds), and therefore are not subject to current requirements of FMVSS 
No. 216. Given that the data in Table 3 show a greater average roof 
crush for heavier light trucks, the agency believes that this fleet 
data suggest the need to regulate a greater percentage of light trucks 
traveling on U.S. highways.
    In addition, sales of new light trucks with a GVWR of 2,722 
kilograms (6,000 pounds) to 4,536 kilograms (10,000 pounds) GVWR have 
been increasing rapidly. According to Polk New Vehicle Registry, the 
number of new registrations has increased from 2.3 million for model 
year 1997 to 3.5 million for model year 2001.\52\ That number 
represents 21 percent of the total number of light duty vehicles sold 
in the United States in 2001. With the increasing sales volume of 
``heavier'' light trucks, the number of passenger-carrying vehicles not 
subject to the requirements of FMVSS No. 216 is increasing every year.
---------------------------------------------------------------------------

    \52\ http://www.polk.com/products/new_vehicle_data.asp.
---------------------------------------------------------------------------

    Also, we note that analysis of recent safety data shows that a 
significant number of serious and fatal injuries occur during rollovers 
in light trucks with a GVWR between 2,722 kilograms (6,000 pounds) and 
4,536 kilograms (10,000 pounds). Specifically, 412 belted, not fully 
ejected occupants are killed or seriously injured every year in light 
trucks with a GVWR between 2,722 kilograms (6,000 pounds) and 4,536 
kilograms (10,000 pounds) involved in rollover crashes resulting in 
roof intrusion. Among these 412 fatally or seriously injured occupants, 
we estimate that 129 could potentially benefit from upgraded roof crush 
resistance requirements because they suffered their most severe (MAIS) 
injury from roof contact.
    Further, the number of light trucks with a GVWR between 2,722 
kilograms (6,000 pounds) and 4,536 kilograms (10,000 pounds) involved 
in a fatal rollover increased from 1,187 in 1997 to 1,589 in 2001.
    DC and other commenters also argued that larger vehicles have a 
higher ratio of height-to-width, which tends to produce less intrusion 
in rollover crashes. However, no data were provided to support their 
argument. In addition, Table 3 shows that 55 percent of light trucks 
with a GVWR between 2,722 kilograms (6,000 pounds) and 4,536 kilograms 
(10,000 pounds) that were involved in rollover crashes experienced at 
least 15 cm (5.9 inches) of vertical roof intrusion. At the same time, 
only 49 percent of light trucks with a GVWR of less than 2,722 
kilograms (6,000 pounds) and 32 percent of passenger vehicles 
experienced similar intrusion levels. Because the likelihood of roof 
intrusion exceeding 15 cm (5.9 inches) is relatively similar among the 
three groups of vehicles (and actually slightly higher for heavier 
light trucks), these data do not suggest a lesser risk of roof contact 
to occupants of light trucks with a GVWR between 2,722 kilograms (6,000 
pounds) and 4,536 kilograms (10,000 pounds) in rollovers than to 
occupants of lighter vehicles.
    Our research indicates that many vehicles with a GVWR between 2,722 
kilograms (6,000 pounds) and 4,536 kilograms (10,000 pounds) would 
comply with current roof crush requirements of FMVSS No. 216. The 
agency recently conducted roof crush testing on six vehicles with a 
GVWR over 2,722 kilograms (6,000 pounds).\53\ All six vehicles met the 
requirements of the current standard.\54\ We anticipate that the 
compliance burdens associated with the proposed roof strength 
requirements would be similar for vehicles with a GVWR between 2,722 
kilograms (6,000 pounds) and 4,536 kilograms (10,000 pounds) as for 
those lighter vehicles already subject to the requirements of FMVSS No. 
216.
---------------------------------------------------------------------------

    \53\ The six vehicles were: MY 1999 Ford E-150, MY 2001 
Chevrolet Tahoe, MY 2002 Dodge Ram, MY 2003 Ford F-150, MY 2003 Ford 
Expedition, and MY 2003 Chevy Express.
    \54\ See Docket Number NHTSA-2005-22143.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    We also note that, in addition to structural integrity of the 
vehicle, other new vehicle design considerations affecting the handling 
and stability of the vehicle, such as vehicle track width, suspension 
system, and placard tire pressure, have a commensurate or even greater 
influence on rollover propensity.

[[Page 49234]]

An expanded discussion of the potential impacts is included in the 
PRIA.
    Further, previous NHTSA research evaluated four Nissan vehicles 
modified for increased roof strength.\58\ The CG height for each 
modified vehicle varied between 25 mm above and 25 mm below the 
baseline vehicle. We also note that the CG height varied by more than 6 
mm even between two similar baseline vehicles. This data further 
supports the agency's findings that increases in the roof structural 
strength will not have a physically measurable influence on the CG 
height, and that influence on CG is commensurate with other vehicle 
design characteristics and production variations.
---------------------------------------------------------------------------

    \58\ ``Design Modification for a 1989 Nissan Pick-up--Final 
Report,'' DOT HS 807 925, NTIS, Springfield, Virginia, 1991.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    Multi-stage vehicles are aimed at a variety of niche markets, most 
of which are too small to be serviced economically by single stage 
manufacturers. Some multi-stage vehicles are built from chassis-cabs 
that have intact roof designs. Others are built from less complete 
vehicles and are designed to service particular needs--often 
necessitating the addition by the final stage manufacturer of its own 
roof or occupant compartment. In considering requirements applicable to 
this segment of the motor vehicle market, the agency must consider a 
number of principles.
    First, the mandate in the Vehicle Safety Act that the agency 
consider whether a proposed standard is appropriate for the particular 
type of motor vehicle for which it is prescribed is intended to ensure 
that consumers are provided an array of purchasing choices and to 
preclude standards that will effectively eliminate certain types of 
vehicles from the market. See Chrysler Corporation v. Dept. of 
Transportation, 472 F.2d 659,679 (6th Cir. 1972) (agency may not 
establish a standard that effectively eliminates convertibles and 
sports cars from the market). Second, the agency may not provide 
exemptions for single manufacturers beyond those specified by statute. 
See Nader v. Volpe, 320 F. Supp. 266 (D.D.C. 1970), motion to vacate 
affirmance denied, 475 F.2d 916 (DC Cir. 1973). Finally, the agency 
must provide adequate compliance provisions applicable to final stage 
manufacturers. Failing to provide these manufacturers with a means of 
establishing compliance would render a standard impracticable as to 
them. See National Truck Equipment Association v. National Highway 
Traffic Safety Administration, 919 F.2d 1148 (6th Cir. 1990) 
(``NTEA'').
    One of the traditional ways in which the agency has handled 
compliance issues associated with multi-stage vehicles has been simply 
to exclude from the scope of the standard all vehicles, single-stage as 
well as multi-stage, within the upper GVWR range of light vehicles, 
typically from 8,500 pounds GVWR to 10,000 pounds GVWR. Many of the 
multi-stage vehicles manufactured for commercial use cluster in that 
GVWR range.\61\
---------------------------------------------------------------------------

    \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.''
---------------------------------------------------------------------------

    The agency traditionally took this approach because the agency 
historically was of the view that it could not subject vehicles built 
in multiple-stages to any different requirements than those built in a 
single-stage. That was because the agency had construed 49 U.S.C. 
30111(b)(3), which instructs the agency to ``consider whether a 
proposed standard is reasonable, practicable, and appropriate for the 
particular type of motor vehicle . . . for which it is prescribed,'' as 
precluding such an approach.
    In reaching that conclusion, the agency had focused on a comment in 
the Senate Report:

    In determining whether any proposed standard is ``appropriate'' 
for the particular type of motor-vehicle * * * for which it is 
prescribed, the committee intends that the Secretary will consider 
the desirability of affording consumers continued wide range of 
choices in the selection of motor vehicles. Thus it is not intended 
that standards will be set which will eliminate or necessarily be 
the same for small cars or such widely accepted models as 
convertibles and sports cars, so long as all motor vehicles meet 
basic minimum standards. Such differences, of course, would be based 
on the type of vehicle rather than its place of origin or any 
special circumstances of its manufacturer.

    Focusing on the last sentence of that passage, the agency had 
concluded that the number of stages in which a vehicle was built was a 
``special circumstance[s] of its manufacturer,'' (see, e.g., 60 FR 
38749, 38758, July 28, 1995), rather than considering a multi-stage 
vehicle to be a ``type of vehicle.'' But see NTEA (at 1151) (Noting the 
agency's regulation defining ``incomplete vehicle'' as ``as assemblage 
consisting as a minimum, of frame and chassis structure, power train, 
steering system, suspension system, and braking system, to the extent 
that those systems are to be part of the completed vehicle that 
requires further manufacturing operations * * * to become a completed 
vehicle. 49 CFR 568.3 (1989).''
    We have reconsidered our historical view in light of relevant case 
law and our experience with the compliance difficulties imposed on 
final stage manufacturers. We note that the language we had previously 
considered to be a limitation does not appear in the statutory text. 
Nothing in the statutory text implies that Congress intended that 
incomplete vehicles not be deemed a vehicle type subject to special 
consideration during the regulatory process. We believe the sentence 
found in the Senate Report was intended to avoid regulatory 
distinctions based on manufacturer-specific criteria (such as place of 
production or manner of importation). This is consistent with the 
Court's conclusion in Nader v. Volpe, supra, that the agency cannot 
give exemptions to particular manufacturers beyond those provided by 
the statute.
    We also had overlooked the existence of relevant physical 
attributes of multi-stage vehicles. Most multi-stage vehicles have 
distinct physical features related to their end use. Especially in the 
context of the difficulties of serving niche markets, the physical 
limitations of incomplete vehicles can adversely affect the ability of 
multi-stage manufacturers

[[Page 49235]]

to design safety performance into their completed vehicles.
    Further, as previously applied, our interpretation limits our 
ability to secure increases in safety. Excluding all vehicles within a 
given GVWR range from a safety requirement because of the possible 
compliance difficulties of some of those vehicles means not obtaining 
the safety benefits of that requirement for any of those vehicles. 
Likewise, applying less stringent requirement to all of those vehicles 
because of multi-stage considerations would also entail a loss of 
safety benefits.
    It would be perverse to conclude that Vehicle Safety Act permits us 
to exclude all vehicles within a certain GVWR range primarily based on 
the compliance difficulties of multi-stage vehicles within that range, 
but not to exclude only the multi-stage vehicles within that range, 
thus enabling consumers to obtain the safety benefits of regulating the 
other vehicles within that weight range.
    In the context of this rulemaking, we believe it appropriate to 
consider incomplete vehicles, other than those incorporating chassis-
cabs, as a vehicle type subject to different regulatory requirements. 
We anticipate that final stage manufacturers using chassis cabs to 
produce multi-stage vehicles would be in position to take advantage of 
``pass-through certification'' of chassis cabs, and therefore do not 
propose including such vehicles in the category of those for whom this 
optional compliance method is available.
    Thus, we are proposing to allow final stage manufacturers to 
certify non-chassis-cab vehicles to the roof crush requirements of 
FMVSS No. 220, as an alternative to the requirements of FMVSS No. 216. 
We decided to propose this approach instead of excluding most multi-
stage vehicles by proposing to exclude all vehicles with a GVWR above 
8,500 pounds. The latter approach would have excluded some vehicles, 
e.g., 15-passenger vans and vehicles built from chassis-cabs, that we 
tentatively conclude should be subject to the proposed upgraded 
requirements of FMVSS No. 216.
    The requirements in FMVSS No. 220 have been effective for school 
buses, but we are concerned that they may not be as effective for other 
vehicle types. As noted above, the FMVSS No. 216 test procedure results 
in roof deformations that are consistent with the observed crush 
patterns in the real world for light vehicles. Because of this, NHTSA's 
preference would be to use the FMVSS No. 216 test procedure for light 
vehicles. However, this approach would fail to consider the 
practicability problems and special issues for multi-stage 
manufacturers.
    In these circumstances, NHTSA believes that the requirements of 
FMVSS No. 220 appear to offer a reasonable avenue to balance the desire 
to respond to the needs of multi-stage manufacturers and the need to 
increase safety in rollover crashes. Several states already require 
``para-transit'' vans and other buses, which are typically manufactured 
in multiple stages, to comply with the roof crush requirements of FMVSS 
No. 220. These states include Pennsylvania, Minnesota, Wisconsin, 
Tennessee, Michigan, Utah, Alabama, and California. NHTSA tentatively 
concludes that these state requirements show the burden on multi-stage 
manufacturers for evaluating roof strength in accordance with FMVSS No. 
220 is not unreasonable, and applying FMVSS No. 220 to these vehicles 
would ensure that there are some requirements for roof crush protection 
where none currently exist.
3. Convertibles
    Currently, convertibles are excluded from the requirements of FMVSS 
No. 216. FMVSS No. 216 does not define the term ``convertibles.'' 
However, S3 of 49 CFR 571.201 defines ``convertibles'' as vehicles 
whose A-pillars are not joined with the B-pillars (or rearmost pillars) 
by a fixed, rigid structural member. In a previous rulemaking, NHTSA 
stated that ``open-body type vehicles'' \62\ are a subset of 
convertibles and are therefore excluded from the requirements of FMVSS 
No. 216.\63\
---------------------------------------------------------------------------

    \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).
---------------------------------------------------------------------------

    However, NHTSA has reassessed its position with respect to ``open-
body type vehicles.'' Specifically, we believe that we were incorrect 
in stating that ``open-body type vehicles'' were a subset of 
convertibles because some open-body type vehicles do not fall under the 
definition of convertibles in S3 of FMVSS No. 201. For example, a Jeep 
Wrangler has a rigid structural member that connects the A-pillars to 
the B-pillars. The Jeep Wrangler is an ``open-body type vehicle'' 
because it has a removable compartment top, but it does not fall under 
the definition of convertibles because its A-pillars are connected with 
the B-pillars through the structural member.
    The agency believes that ``open-body type vehicles'' such as the 
Jeep Wrangler are capable of offering roof crush protection over the 
front seat area. Accordingly, the agency proposes to limit the 
exclusion from the requirements of FMVSS No. 216 to only those vehicles 
whose A-pillars are not joined with the B-pillars, thus providing 
consistency with the definition of a convertible in S3 of FMVSS No. 
201. To clarify the scope of the exemption for convertible vehicles, we 
are proposing to add the definition of convertibles contained in S3 of 
49 CFR 571.201 to the definition section in FMVSS No. 216.
    The agency seeks comments on the following:
    1. The number of vehicle lines that fall under the definition of 
``open-body type vehicles,'' but do not fall under the definition of 
convertibles.
    2. The roof crush performance of open-body type vehicles that do 
not fall under the definition of convertibles.
    3. The feasibility of requiring that open-body type vehicles meet 
FMVSS No. 216.

B. Proposed Amendments to the Roof Strength Requirements

1. Increased Force Requirement
    Currently, FMVSS No. 216 requires that the lower surface of the 
test plate not move more than 127 mm (5 inches), when it is used to 
apply a force equal to 1.5 times the unloaded weight of the vehicle to 
the roof over the front seat area. For passenger cars, the applied 
force cannot exceed 22,240 Newtons (5,000 pounds). As a result, 
passenger cars that have an unloaded weight above 1,512 kilograms 
(3,333 pounds) are, in effect, tested to a less stringent requirement 
than other passenger cars and light trucks under the current 
standard.\64\ Based on the agency analysis of crash data, as well as 
comments in response to the October 2001 RFC, NHTSA is proposing to 
require that the roof over the front seat area withstand the force 
increase equal to 2.5 times the unloaded weight of the vehicle, and to 
eliminate the 22,240 Newton (5,000 pound) force limit for passenger 
cars.
---------------------------------------------------------------------------

    \64\ 5,000 pounds / 1.5 = 3,333 pounds.
---------------------------------------------------------------------------

Increase Applied Force to 2.5 Times the Unloaded Vehicle Weight
    NHTSA believes that FMVSS No. 216 could protect front seat 
occupants better if the applied force requirement reduced the extent of 
roof crush occurring in real world crashes. That is, the increased 
applied force requirement would lead to stronger roofs and reduce the 
roof crush severity observed in real world crashes. We observed that in 
many real-world rollovers, vehicles subject to the

[[Page 49236]]

requirements of FMVSS No. 216 experienced vertical roof intrusion 
greater than the test plate movement limit of 127 mm (5 inches). 
Specifically, from the 1997-2002 NASS-CDS data, we estimate that 32 
percent of passenger cars and 49 percent of light trucks with a GVWR 
under 2,722 kilograms (6,000 pounds) exceed 150 mm (5.9 inches) of 
vertical roof intrusion. Further, 55 percent of light trucks with a 
GVWR greater than 2,722 kilograms (6,000 pounds) and less than or equal 
to 4,536 kilograms (10,000 pounds) exceed 150 mm (5.9 inches) of 
vertical roof intrusion.\65\ Based on these data, we have tentatively 
concluded that the test force should be increased.
---------------------------------------------------------------------------

    \65\ Table 3 shows the percent of roof-involved rollover 
vehicles with particular degrees of vertical roof intrusion by 
vehicle body type.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    Public Citizen and several individual commenters on the October 
2001 RFC suggested that NHTSA require a vehicle to withstand an applied 
force of 3.0 to 3.5 times the unloaded vehicle weight in order to 
better replicate dynamic forces occurring in rollover crashes. Carl 
Nash suggested that the agency propose a new requirement that the roof 
must sustain 1.5 times vehicle's GVWR before 127 mm (5 inches) of plate 
movement and sustain a force that does not drop more than 10 percent 
during the test. After the force of 1.5 times the GVWR has been 
achieved, the force should be increased to 2.5 times the vehicle's GVWR 
without any further roof deformation.
    In response to these comments, the agency notes that it previously 
conducted a study (Rains study) \67\ that measured peak forces 
generated during quasi-static testing under FMVSS No. 216 and under SAE 
J996 inverted drop testing. In the Rains study, nine quasi-static tests 
were first conducted. The energy absorption was measured and used to 
determine the appropriate corresponding height for the inverted drop 
conditions. Six of the vehicles were then dropped onto a load plate. 
The roof displacement was measured using a string potentiometer 
connected between the A-pillar and roof attachment and the vehicle 
floor. The peak force from the drop tests was limited to only the first 
74 mm (3 inches) of roof crush because some of the vehicles rolled and 
contacted the ground with the front of the hood. Similarly, the peak 
quasi-static force was limited during the first 127 mm (5 inches) of 
plate movement. This report showed that for the nine quasi-static 
tests, the peak force-to-weight ratio ranged from 1.8 to 2.5. Six of 
these vehicle models were dropped at a height calculated to set the 
potential energy of the suspended vehicle equal to the static tests. 
For these dynamic tests, the peak force-to-weight ratio ranged from 2.1 
to 3.1. In sum, the agency concluded that 2.5 was a good representation 
of the observed range of peak force-to-weight ratio.
---------------------------------------------------------------------------

    \67\ Glen C. Rains and Mike Van Voorhis, ``Quasi Static and 
Dynamic Roof Crush Testing,'' DOT HS 808-873, 1998.
---------------------------------------------------------------------------

    The agency believes that manufacturers will comply with this 
standard by strengthening reinforcements in roof pillars, by increasing 
the gauge of steel used in roofs or by using higher strength materials. 
The agency estimates that 32 percent of all current passenger car and 
light truck models will need changes to meet the 2.5 load factor 
requirement.
    The agency has tentatively concluded that 2.5 constitutes a load 
factor appropriate to enhance roof crush performance. As described 
above, roof crush performance is but one of several measures necessary 
to reduce rollover related fatalities and injuries. Continued 
improvements in driver behavior, combined with advanced technologies 
such as electronic stability control systems and lane departure 
warnings will further reduce those fatalities and injuries.
    Further, NHTSA's New Car Assessment Program (NCAP) provides a 
strong incentive for manufacturers to design vehicles that will attain 
favorable Static Stability Factors (representing the relatively 
numerous tripped rollovers) and that will perform well in the dynamic 
maneuver (representing the relatively few untripped rollovers), as well 
as meeting the minimum load factor of 2.5.
    Safety Analysis and Forensic Engineering (SAFE) and Syson-Hille and 
Associates argued that solely attaining the peak force is not a useful 
indicator of roof crush resistance performance because the peak forces 
often drop significantly due to breaking glass and other structural 
failures. They recommend an energy absorption requirement in order to 
prevent roof collapse after initial peak forces are attained. The 
agency has not previously considered adding an energy absorption 
requirement to FMVSS No. 216 and would have to conduct significant 
additional analysis in order to evaluate the energy absorption 
requirement and determine appropriate parameters for testing. 
Accordingly, the agency is not proposing an energy absorption 
requirement in this document. Nevertheless, the agency would welcome 
comments on energy absorption test described by SAFE and Syson-Hille.
Eliminate 22,240 Newton Force Limit for Passenger Cars
    At the inception of the standard, some passenger cars were not 
subjected to the full requirements of the standard, which mandated the 
roof over the front seat area to withstand the force of 1.5 times the 
unloaded vehicle weight. For passenger cars, this force was limited to 
22,240 Newtons (5,000 pounds). That meant that heavier passenger cars 
were not tested at 1.5 times their unloaded vehicle weight. In fact, 
every passenger car weighing more than 1,512 kg (3,333 pounds) was 
subjected to less stringent requirements. The purpose of this limit was 
to avoid making it necessary for manufacturers to redesign large cars 
that could not meet the full roof strength requirements of the 
standard.\68\ At the time, the agency believed that requiring larger 
passenger cars to comply with the full (1.5 times the unloaded vehicle 
weight) requirement would be unnecessary because heavy passenger cars 
had lower rollover propensity. However, as explained below, the agency 
tentatively concludes that occupants of passenger cars weighing more 
than 1,512 kg (3,333 pounds) are sustaining rollover-related injuries 
and therefore require the same level of roof crush protection as other 
vehicles subject to the standard.
---------------------------------------------------------------------------

    \68\ See 54 FR 46276.
---------------------------------------------------------------------------

    While passenger car rollover propensity is lower than it is for 
light trucks, these vehicles can and do experience rollover crashes. 
Recent crash data indicate that this is just as true for passenger cars 
with unloaded vehicle weight of over 1,512 kg (3,333 pounds), as it is 
for cars with lower unloaded vehicle weights. Specifically, out of an 
annually estimated 6,274 seriously or fatally injured belted and not 
fully ejected occupants of passenger cars involved in rollovers 
resulting in roof intrusion, an estimated 1,460 (23 percent) were in 
passenger cars that had an unloaded vehicle weight of over 1,512 kg 
(3,333 pounds). Further, corporate average fuel economy (CAFE) data 
have shown that from 1991 to 2001, the average weight of passenger cars 
has

[[Page 49237]]

increased more than 7 percent.\69\ This trend suggests that more 
passenger cars are being subjected to less stringent roof crush 
resistance requirements each year. Based on these data, the agency 
believes that occupants of passenger vehicles with unloaded vehicle 
weight of over 1,512 kg (3,333 pounds) should be afforded the same 
level of roof crush protection that is being offered by lighter 
passenger cars and light trucks.
---------------------------------------------------------------------------

    \69\ http://www.nhtsa.dot.gov/cars/rules/CAFE/NewPassengerCarFleet.htm.
---------------------------------------------------------------------------

    In addition, we note that the manufacturers already produce heavier 
passenger cars that exceed the current requirements of the standard. 
Recently, the agency tested several passenger cars with an unloaded 
weight of near or over 1,512 kilograms (3,333 pounds). The roof of each 
vehicle withstood the force of at least 1.5 times the unloaded vehicle 
weight. For example, MY 2002 Ford Crown Victoria with an unloaded 
vehicle weight of 1,788 kilograms (3,942 pounds) withstood an applied 
force of almost 2 times the unloaded vehicle weight (3671 kilograms 
(8,093 pounds)) before 127 mm (5 inches) of plate movement was 
attained. A MY 2004 Lincoln LS with an unloaded vehicle weight of 1,663 
kilograms (3,666 pounds) withstood an applied force of slightly greater 
than 2.5 times (4,290 kilograms, (9,458 pounds)) the unloaded vehicle 
weight before 127 mm (5 inches) of plate movement was attained.
2. Headroom Requirement
    The current standard requires that the lower surface of the test 
device not move more than 127 mm (5 inches) under the specified applied 
force. The purpose of the requirement is to limit the amount of roof 
intrusion into the occupant compartment. However, the agency now 
believes that the 127 mm (5 inch) limit is not the most effective way 
to ensure that front seat area occupants are protected from roof 
intrusion into the occupant compartment. Specifically, we are concerned 
that this requirement does not provide adequate protection to front 
outboard occupants of vehicles with a small amount of occupant headroom 
and may impose a needless burden on vehicles with a large amount of 
occupant headroom. For example, in a full size van with a substantial 
amount of pre-crush headroom, the 127 mm (5 inch) plate movement limit 
ensures that the collapsed portion of the roof would not contact the 
front seat occupants. However, in a low roofline sports vehicle, the 
127 mm (5 inch) plate movement limit might allow the crushed portion of 
the roof to contact the head of an average size front seat occupant.
    Therefore, the agency is proposing a more direct limit on headroom 
reduction that would prohibit any roof component from contacting a 
seated 50th percentile male dummy under the application of a force 
equivalent to 2.5 times the unloaded vehicle weight. This direct 
headroom reduction limit would ensure that motorists receive an 
adequate level of roof crush protection regardless of the type of 
vehicle in which they ride.
    In response to the October 2001 RFC, Ford, Nissan, GM, DC, and 
Biomech commented that real-world data indicate that it is not possible 
to estimate quantifiable benefits of headroom reduction limits. 
However, Ford also suggested that reducing the roof/pillar deformation 
might benefit belted occupants if it results in the occupant not 
contacting the roof.
    In contrast, Public Citizen and numerous individual commenters 
asserted that a minimum headroom clearance requirement should be 
established because they believe that roof crush is related to head and 
neck injury. Nash stated that limiting the extent and character of roof 
intrusions can virtually eliminate the risks of serious head and neck 
injury to restrained occupants in rollover crashes. Nash suggested that 
NHTSA define headroom reduction limits by using a 50th percentile dummy 
seat in the front outboard seat. Public Citizen and several other 
commenters suggested that the standard contain an occupant survival 
space/non-encroachment zone, which would not be intruded upon during 
the test, using a 95th percentile dummy.
    The 95th percentile Hybrid III male dummy has not been incorporated 
into 49 CFR Part 572, Anthropomorphic Test Devices, and is not yet 
available for compliance purposes. When the dummy is available, the 
agency will consider whether it is appropriate to propose using this 
dummy for compliance testing.
    To help evaluate the value of a minimum headroom requirement, NHTSA 
performed statistical analysis and published its findings in a report 
entitled, ``Determining the Statistical Significance of Post-Crash 
Headroom for Predicting Roof Contact Injuries to the Head, Neck, or 
Face during FMVSS No. 216 Relevant Rollovers.'' \70\ This report 
examined the effect of post-crash headroom (defined as the vertical 
distance from the top of the occupant's head to the top of the roof 
liner over the occupant's head after rollover) on injuries to the head, 
neck, or face from contact with a roof component. We examined light 
duty vehicles that rolled more than one-quarter turn to the side or 
end-over-end and did not collide with fixed objects. The vehicle 
occupants were adults who were belted and seated in the front outboard 
seats and who were not ejected. Based on this report, the agency 
estimates that 14 percent of the non-ejected, belted occupants sitting 
in the two front outboard seats suffered a roof contact injury to the 
head, neck, or face, and 0.1 percent died as a result of such an 
injury.
---------------------------------------------------------------------------

    \70\ See Docket Number NHTSA-2005-22143.
---------------------------------------------------------------------------

    The agency analyzed crash data using two sets of headroom 
measurement parameters from NCAP/FMVSS No. 208 frontal testing and CU 
testing. Using NCAP/FMVSS No. 208 headroom measurement parameters, we 
estimate that 9 percent of occupants with post-crash headroom above the 
top of their head experienced roof contact injuries to the head, neck, 
or face, compared to 34 percent for occupants with post-crash headroom 
below the top of their head. Using CU vehicle headroom measurement 
parameters, we estimate that 10 percent of occupants with post-crash 
headroom above the top of their head experienced roof contact injuries 
to the head, neck, or face, compared to 32 percent for occupants with 
post-crash headroom below their head. After conducting bivariate and 
multivariate analyses, we conclude that positive post-crash headroom 
(residual space over the occupant's head after the rollover) reduced 
the likelihood of suffering a roof contact injury to the head, neck, or 
face. This real world data shows quantifiable benefits of limiting 
headroom reduction.
    As previously stated, the agency is proposing to prohibit any roof 
component or the test device from contacting a seated 50th percentile 
male Hybrid III dummy under the specified applied force. However, the 
agency is concerned that there may be some low roofline vehicles \71\ 
in which the 50th percentile Hybrid III dummy would have relatively 
little available headroom when positioned properly in the seat. That 
is, we are concerned that, in some limited circumstances, the headroom 
between the head of a 50th percentile male dummy and the roof liner is 
so small that even minimal deformation resulting from the application 
of the required force would lead to test failure. Accordingly, NHTSA 
requests comments on whether any additional or substitute requirements 
would be

[[Page 49238]]

appropriate for low roofline vehicles in order to make the standard 
practicable.
---------------------------------------------------------------------------

    \71\ Ford GT, Lamborghini Gallardo.
---------------------------------------------------------------------------

    The agency believes that many vehicles subject to the current 
requirements of FMVSS No. 216 would meet the proposed limit on headroom 
reduction. In the recent tests of 20 vehicles of various types and 
sizes in which the roofs were crushed to 254 mm (10 inches) of 
displacement, thirteen vehicles had remaining headroom under an applied 
force of 2.5 times the unloaded vehicle weight. These thirteen vehicles 
were randomly distributed through the various vehicle types. Based on 
these tests, the agency believes that vehicle manufacturers are capable 
of complying with the proposed headroom requirements. In response to 
the concerns expressed by SEMA with respect to installation of sunroofs 
and moon roofs, we note that one of the tested vehicles was a Nissan 
Quest equipped with a Sky View\TM\ glass-paneled roof consisting of a 
sunroof and two separate glass panels. This vehicle withstood the force 
of up to 2.8 times the unloaded vehicle weight with 3 inches of 
displacement.
    Finally, in conjunction with the proposed headroom requirement, 
NHTSA is proposing to create a definition for ``roof component,'' which 
is similar to the definition found in the NASS-CDS. Specifically, a 
``roof component'' would include the A-pillar, B-pillar, front header, 
rear header, roof side rails, roof, and all the corresponding interior 
trim. Due to vast variations in roof designs, the agency proposes a 
``no-contact'' requirement for all roof components, as opposed to only 
the actual roof structure. The agency requests comments on the proposed 
definition.

C. Proposed Amendments to the Test Procedures

1. Retaining the Current Test Procedure
    To test compliance, the vehicle is secured on a rigid horizontal 
surface, and a steel rectangular plate is angled and positioned on the 
roof to simulate vehicle-to-ground contact over the front seat area. 
This plate is used to apply the specified force to the roof structure.
    Plate position and angle. In response to the October 2001 RFC, the 
agency received several suggestions regarding the current quasi-static 
test procedure. Specifically, CU suggested establishing a new plate 
position, for which the specific application points would be (1) the 
top of the A-pillar; (2) the top of the rear most pillar, either the B-
pillar on a pickup, C-pillar on sedans or the D-pillar on station 
wagons, SUVs or minivans; and (3) the horizontal and vertical axes at 
the center of the roof side, usually about the top of the B-pillar. CU 
and several individual commenters recommended that a more 
representative plate angle should be 45-degrees for vehicles with a 
taller, narrower body configuration. SAFE stated that the roll angle 
should be increased in an attempt to simulate the translational effect 
of the vehicle traveling across the ground.
    In response, NHTSA reviewed NASS-CDS crash data to examine roof 
deformation patterns and compare real-world roof damage to compliance 
tests.\72\ The agency also compared its findings to the previous study 
on roof deformation patterns.\73\ The agency evaluated the damage to 
the A- and B-pillars, roof rails and roof plane of the vehicles. Based 
on the NASS-CDS crash data, we believe that the current test procedure 
is capable of applying loads resulting in crush patterns consistent 
with those that occur in the real world.
---------------------------------------------------------------------------

    \72\ See Docket Number NHTSA-1999-5572-95.
    \73\ Michael J. Leigh and Donald T. Willke, ``Upgraded Rollover 
Roof Crush Protection: Rollover Test and NASS Case Analysis,'' 
Docket NHTSA-1996-1742-18, June 1992.
---------------------------------------------------------------------------

    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\
---------------------------------------------------------------------------

    \74\ See Docket No. NHTSA-2005-22143.
---------------------------------------------------------------------------

    NHTSA also conducted a finite element modeling study to examine the 
effect of using alternative roll and pitch angles for the current FMVSS 
No. 216 test procedure.\75\ A model of a 1998 Dodge Caravan was used to 
simulate extended FMVSS No. 216 tests for approximately 127 mm (5 
inches) of plate motion using a variety of roll and pitch angles. The 
simulations predicted that the Caravan roof would attain similar 
amounts of deformation at a lower force level using 10-degree pitch and 
45-degree roll (10-45) application angles compared to the current 5-
degree pitch and 25-degree roll (5-25) application angles. In addition, 
a 1998 Chevrolet S10 pickup model was analyzed in subsequent 
simulations, but led to less conclusive results.
---------------------------------------------------------------------------

    \75\ ``Roof Crush Research: Load Plate Angle Determination and 
Initial Fleet Evaluation.'' Docket No. NHTSA-2005-22143.
---------------------------------------------------------------------------

    The results of the finite element modeling study were sufficiently 
encouraging to conduct a series of modified FMVSS No. 216 tests. Two 
tests were conducted on Dodge Caravan, Chevrolet S10, and 2002 Ford 
Explorer vehicles using both the current 5-25 degree application angles 
as well as using modified 10-45 degree application angles. Each test 
was conducted until 254 mm (10 inches) of load plate movement was 
achieved.
    The roof damage produced by the two test configurations was 
generally similar. The tests using 10-45 degree application angles had 
some additional lateral damage. However, the damage was localized near 
the roof side rail and did not extend laterally to the midline of the 
vehicle. The force distribution applied to the front and back of the 
load plate changed considerably between the two test configurations. 
The test configuration using the 10-45 degree application angles 
applied almost all of the force to the forward ram located near the 
front of the load plate. Comparatively, the 5-25 configuration applied 
only two-thirds of the force to the front ram. Based on the similarity 
of the post-test damage patterns and general force levels, the agency 
concluded that there was not sufficient reason to propose a change in 
the load plate configuration at this time.
    Testing without windshield and/or side windows in place. Public 
Citizen, CU, and several individual commenters stated that the quasi-
static test should be conducted without the windshield and/or side 
glass. The comments stated that the glass usually breaks after the 
first quarter-turn, resulting in virtually no support to the roof on 
subsequent rollovers, and that the roof crush severity substantially 
increases after the integrity of the windshield is breached.
    The agency believes that windshields provide some structural 
support to the roof even after the windshield breaks because the force-
deflection plots in some of the recent test vehicles (e.g., Ford 
Explorer, Ford Mustang, Toyota Camry, Honda CRV) show little or no drop 
in force level after the windshield

[[Page 49239]]

integrity was compromised.\76\ Further, examination of real-world 
rollover crashes indicates that the windshield rarely separates from 
the vehicle, and therefore, does provide some crush resistance. Because 
NHTSA believes that the vehicle should be tested with all structural 
components that would be present in a real-world rollover crash, we 
decline to propose testing without the windshield or other glazing.
---------------------------------------------------------------------------

    \76\ See id.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \77\ Near side is the side toward which the vehicle begins to 
roll and far side is the trailing side of the roll.
    \78\ Parenteau, Chantal, Madana Gopal, David Viano. ``Near and 
Far-Side Adult Front Passenger Kinematics in a Vehicle Rollover.'' 
SAE Technical Paper 2001-01-0176, SAE 2001 World Congress, March 
2001.
---------------------------------------------------------------------------

    In response, NHTSA conducted six tests (2 Lincoln LS, Ford Crown 
Victoria, Chrysler Pacifica, Nissan Quest, Land Rover Freelander), in 
which both sides of the vehicle roof were crushed. Using the current 
FMVSS No. 216 test plate angles, the first side was crushed up to 
approximately 100 mm (4 inches) of plate movement. The test plate 
motion compromised the windshield structure in each vehicle. The 
similar procedure was performed on the opposite side of the vehicle. 
However, the crush was extended up to 254 mm (10 inches) of plate 
movement. Detailed reports for these tests are available in the NHTSA 
docket.\79\
---------------------------------------------------------------------------

    \79\ See Docket Number NHTSA-2005-22143.
---------------------------------------------------------------------------

    In summary, the first and second side force deflection curves track 
similarly for the Pacifica and Quest. For the Crown Victoria, the first 
and second side force curves tracked similarly except between 50-90 mm 
of crush. During that portion of the curve, the local peak was reduced 
17 percent on the second side. However, after 90 mm, the second side 
force curve tracked similarly to the previously tested Crown Victoria 
\80\ that was crushed to 254 mm (10 inches) of plate movement. For the 
Freelander, the second side force curve showed an increase in force 
over the first side, starting at approximately 40 mm of plate movement. 
As a result, the local peak force was increased by approximately 20 
percent on the second side. In contrast, the second side force curve of 
the Lincoln LS showed a decrease in force starting at approximately 40 
mm of plate movement. As a result, the local peak force was decreased 
by approximately 20 percent on the second side.
---------------------------------------------------------------------------

    \80\ ``Roof Crush Research: Load Plate Angle Determination and 
Initial Fleet Evaluation.'' Docket No. NHTSA-2005-22143.
---------------------------------------------------------------------------

    To evaluate the repeatability of the tests, the agency performed 
the identical test procedure on a second Lincoln LS. For the second LS 
test, both the first and second side force curves tracked similarly to 
the curves of the first LS test up to approximately 40 mm. However, the 
local peak for the first side was slightly lower than the first test 
and the local peak for the second side was slightly higher than the 
first test on the second side. As a result, the difference in the local 
peak force between the first and second side was approximately 10 
percent.
    In conclusion, the agency believes that some vehicles may have 
weakened or strengthened far side roof structures as a result of a near 
side impact. However, based on the few vehicles tested, NHTSA does not 
have enough information to make a decision on the merits of testing 
both sides of the roof over the front seat area. The agency plans to 
conduct further research before it proposes rulemaking action in this 
area.
    On July 26, 2004, JP Research, Inc. submitted an evaluation of the 
Delphi Automotive and Saab research paper (Delphi research paper) \81\ 
relied upon by Public Citizen.\82\ JP Research discussed the paper with 
one of the principal authors and verified that the paper contained 
errors. Previously, Public Citizen concluded that belted, non-ejected 
occupants on the far side suffer 12 times the risk of serious injuries 
compared to belted, non-ejected occupants on the near side of the 
rolling vehicle. However, as a result of correcting the errors, the 
ratio changes from 12 to 1, to between 2.4 and 1.
---------------------------------------------------------------------------

    \81\ Parenteau, Chantal, Madana Gopal, David Viano. ``Near and 
Far-Side Adult Front Passenger Kinematics in a Vehicle Rollover.'' 
SAE Technical Paper 2001-01-0176, SAE 2001 World Congress, March 
2001.
    \82\ See Docket Number NHTSA-1999-5572-93.
---------------------------------------------------------------------------

    In preparing this document, NHTSA analyzed NASS-CDS (1997 to 2002) 
data to evaluate the Delphi research paper with respect to merits of 
testing both sides of the roof over the front seat area. The analysis 
included belted front outboard adults who were not fully ejected in a 
manner similar to the Delphi research paper, but it further restricted 
the analysis to vehicles that rolled only two to four quarter turns to 
the side. We estimate the risk of a serious injury, defined as a 
maximum AIS injury of 3 or greater, to be 29 seriously injured persons 
per 1000 ``far side'' occupants and 30 seriously injured persons per 
1000 ``near side'' occupants for a ratio of about 1 to 1. Based on this 
analysis, the agency believes that there is no significant increase in 
risk for far side belted, non-ejected occupants.
    In summary, NHTSA continues to believe that the quasi-static test 
procedure is repeatable and capable of simulating real-world rollover 
deformation patterns. Based on the deformation patterns observed in 
NASS-CDS cases, finite element modeling, and various controlled vehicle 
testing, the agency believes that changing the test plate angle is not 
necessary. Further, the agency believes that the vehicle should be 
tested with all structural components that would be present in a real-
world rollover crash, and therefore we decline to propose testing 
without the windshield or other glazing. Finally, the agency plans to 
further evaluate the safety need for testing both sides of the roof 
over the front seat area on the same vehicle, before proposing such a 
requirement.
2. Dynamic Testing
    In response to the October 2001 RFC, we received several comments 
suggesting that the agency adopt some form of dynamic testing of roof 
crush resistance. Specifically, CU and Stilson Consulting urged the 
agency to adopt dynamic testing to replicate better the influence of 
variable crush patterns and vehicle dynamic elements that occur in 
real-world crashes. Further, Hans Hauschild, Hogan, Donald Slavik, and 
Coben and Associates suggested that NHTSA adopt the SAE J996 inverted 
drop test because it better replicates real-world rollover dynamics.
    The Alliance argued that dynamic testing was unrepeatable. DC and 
Biomech stated that they have not

[[Page 49240]]

evaluated dynamic rollover testing and do not know what injury criteria 
might be appropriate for assessing dynamic performance. NTEA stated 
that the benefits of adopting dynamic roof crush testing are unclear. 
Further, NTEA stated that dynamic rollover testing was neither 
economically nor technologically feasible.
    GM, DC, and Biomech stated that inverted drop testing is not 
repeatable and cannot accurately represent real-world rollovers. 
Further, Ford stated that the drop test does not represent the multi-
axis, real-world condition with respect to time duration of impact, and 
does not replicate centrifugal forces on the occupant because the 
velocity of roof rail impact with the ground in a rollover is a 
function of the vehicle's roll rate, translational velocity and 
vertical velocity. Public Citizen asserted that the SAE J996 inverted 
drop test does not accurately reproduce the lateral sliding forces 
present in a rollover crash. Carl Nash stated that the inverted drop 
test can be useful, but does not properly simulate the lateral friction 
forces that are typical in rollovers on the road.
    Based on research discussed in Section V(A) NHTSA believes that the 
inverted drop test does not replicate real-world rollovers better than 
the current quasi-static method of testing. Further, the inverted drop 
test does not produce results as repeatable as the quasi-static method. 
Specifically, NHTSA believes that the drop test would not apply a 
consistent directional force among tested vehicles because of the 
vehicle roll that is introduced after the initial roof impact. 
Depending on the geometry of the roof and hood, vehicles may experience 
different load paths as they roll onto its hood or front-end structure.
    Advocates for Highway Safety (Advocates) suggested that the agency 
consider adopting a series of tests for ensuring adequate roof 
strength. Specifically, Advocates suggested adopting a test similar to 
the FMVSS No. 208 dolly test. Donald Friedman stated that NHTSA should 
consider using the FMVSS No. 208 dolly test for research. By contrast, 
the Alliance, GM, Nissan, Ford, and DC stated that the FMVSS No. 208 
dolly test is not repeatable and does not emulate the dynamics of real-
world rollover crashes. Further, the test was not developed to predict 
roof crush performance. Hauschild suggested that the FMVSS No. 208 
dolly test, while appropriate for evaluating occupant retention for 
belted and unbelted occupants, would not be appropriate for evaluating 
roof strength. Slavik and Syson-Hille asserted that the FMVSS No. 208 
dolly test is useful for examining potential occupant kinematics in 
rollovers, but may not be feasible for pass/fail regulatory purposes 
due to resultant variability in roof impacts and intrusion.
    The FMVSS No. 208 dolly test was originally developed only as an 
occupant containment test. The test was not developed to evaluate the 
loads on specific vehicle components. The agency believes this test 
lacks sufficient repeatability to serve as a structural component 
compliance requirement.
    Biomech Inc. suggested that the agency consider using the 
Controlled Rollover Impact System (CRIS) device \83\ because it 
overcomes the shortcomings of drop testing (lack of roll and 
translational velocity-limiting time exposure of roof-to-ground 
contact) by incorporating important test parameters (roll angle, 
vertical and horizontal velocities and pitch and yaw of the vehicle). 
Ford believes that the CRIS is able to create repeatable dynamic 
rollover impact simulations for the first roof-to-ground impact. By 
contrast, SAFE and several other individual comments suggested that the 
conclusions drawn from the CRIS tests \84\ mischaracterize the real-
world rollover dynamics because the tests were designed to support the 
hypothesis that roof crush does not cause occupant injuries.
---------------------------------------------------------------------------

    \83\ The CRIS consists of a towed semi-trailer, which suspends 
and drops a rotating vehicle from a support frame cantilevered off 
the rear of the trailer.
    \84\ Moffatt, E.A., Cooper, E.R., Croteau, J.J., Orlowski, K.F., 
Marth, D.R., and Carter, J.W. ``Matched-Pair Impacts of Rollcaged 
and Production Roof Cars Using the Controlled Rollover Impact System 
(CRIS),'' Society of Automotive Engineers, 2003-01-0172, Detroit, 
Michigan, 2003.
---------------------------------------------------------------------------

    The agency believes the CRIS device is helpful in understanding 
occupant kinematics during rollover crashes. However, NHTSA believes 
that the device does not provide the level of repeatability needed, 
because the CRIS test is repeatable only up to the initial contact with 
ground. After initial roof impact, the CRIS test allows the vehicle to 
continue rolling, resulting in an unrepeatable test condition.
    Lastly, NHTSA received several comments regarding the Jordan 
Rollover System (JRS) test device. The JRS device rotates a vehicle 
body structure on a rotating apparatus (``spit'') while the road 
surface moves along the track and contacts the roof structure. Public 
Citizen and the Center for Injury Research believe that the JRS test 
can be conducted with dummies that demonstrate whether vehicle roof 
performance meets objective injury and ejection criteria for belted and 
unbelted occupants.
    Although the agency is open to further investigating the JRS test, 
we have no data regarding the repeatability of dummy injury and roof 
intrusion measurements. In addition to data on repeatability, NHTSA 
would need further information on its performance measures, 
practicability, and relevance to real-world injuries.
    In summary, NHTSA is not proposing a dynamic test procedure at this 
time. As previously stated, the agency believes that the current test 
procedure is repeatable and capable of simulating real-world rollover 
deformation patterns. Further, the agency is unaware of any dynamic 
test procedures that provide a sufficiently repeatable test 
environment.
3. Revised Tie-Down Procedures
    Based on recent testing described in Section V(C), NHTSA is 
proposing to revise the vehicle tie-down procedure in order to improve 
test repeatability. Specifically, the agency is proposing to specify 
that the vehicle be secured with 4 vertical supports welded or fixed to 
both the vehicle and the test fixture. If the vehicle support locations 
are not metallic, a suitable epoxy or an adhesive could be used in 
place of welding. Under the proposal, the vertical supports would be 
located at the manufacturers' designated jack points. If the jack 
points are not sufficiently defined, the vertical supports would be 
located between the front and rear axles on the vehicle body or frame 
such that the distance between the fore and aft locations is maximized. 
If the jack points are located on the axles or suspension members, the 
vertical stands would be located between the front and rear axles on 
the vehicle body or frame such that the distance between the fore and 
aft locations is maximized. All non-rigid body mounts would be made 
rigid to prevent motion of the vehicle body relative to the vehicle 
frame.
    The agency believes this method of securing the vehicle would 
increase test repeatability. Welding the support stands to the vehicle 
would reduce testing complexity and variability of results associated 
with the use of chains and jackstands. In addition, the agency believes 
that using the jacking point for vertical support attachment is 
appropriate because the jacking points are designed to accommodate 
attachments and withstand certain loads without damaging the vehicle.
    In previous comments to the Docket, Ford suggested that vehicle 
overhangs should be supported by jackstands in

[[Page 49241]]

order to minimize vehicle distortion.\85\ However, the agency does not 
believe that it is necessary to support the vehicle overhangs. In fact, 
supporting the vehicle overhangs with jackstands could distort the 
shape of the vehicle prior to testing.
---------------------------------------------------------------------------

    \85\ See Docket Number 94-097-N02-010.
---------------------------------------------------------------------------

4. Plate Positioning Procedure
    Currently, the standard contains two test plate positioning 
procedures. The primary procedure applies to most vehicles. It places 
the midpoint of the forward edge of the lower surface of the test 
device within 10 mm (0.4 inches) of the transverse vertical plane 254 
mm (10 inches) forward of the forwardmost point on the exterior surface 
of the roof. The secondary procedure applies to multipurpose passenger 
vehicles and buses with raised or altered roofs, at the option of the 
manufacturer. It places the midpoint of the rearward edge of the lower 
surface of the test device within 10 mm (0.4 inches) of the transverse 
vertical plane located at the rear of the roof over the front seat 
area.
    The agency is proposing to specify the primary test procedure for 
all vehicles. The agency believes that this test plate positioning 
procedure produces repeatable and reliable means for testing roof 
strength. The agency believes that the secondary plate positioning test 
procedure produces rear edge plate loading onto the roof of some raised 
and altered roof vehicles that cause excessive deformation 
uncharacteristic of real-world rollover crashes. Because an optimum 
plate position cannot be established for all roof shapes, the testing 
of some raised and altered roof vehicles will result in loading the 
roof rearward of the front seat area. However, NHTSA believes that this 
is preferable to edge contact because edge contact produces localized 
concentrated forces upon the roof typically resulting in excessive 
shear deformation of a small region. In some circumstances, the plate 
will essentially punch through the sheet metal instead of loading the 
structure. The agency believes that removing the secondary plate 
position would also make vehicle testing more objective and 
practicable. Accordingly, the agency proposes to eliminate the 
secondary positioning procedure.

VIII. Other Issues

A. Agency Response to Hogan Petition

    As previously discussed, on May 6, 1996, the agency received a 
petition for rulemaking from Hogan.\86\ The petitioner claimed that the 
test requirements of FMVSS No. 216 bear no relationship to real-world 
rollover crash conditions, and therefore, should be replaced with a 
more realistic test such as inverted drop test. On January 8, 1997, 
NHTSA granted this petition, believing that the inverted drop test had 
merit for further agency consideration.
---------------------------------------------------------------------------

    \86\ See Docket No. 2005-22143.
---------------------------------------------------------------------------

    After careful evaluation of the issues presented by the Hogan 
petition, the agency has decided against adopting the inverted drop 
test or other dynamic test procedures because we believe that these 
tests are not better than the current quasi-static test in replicating 
real-world rollover crash conditions.
    The agency fully discussed alternatives to the current quasi-static 
test in Section VII(C)(1), (2). First, NHTSA conducted a series of 
inverted drop tests and concluded that the tests were not better than 
quasi-static tests in representing vehicle-to-ground interaction 
occurring during rollover, and were more difficult to conduct because 
they require suspending and inverting the vehicle.\87\ Second, NHTSA 
conducted dynamic rollover tests and observed that dynamic testing 
created test conditions so severe it was difficult to discriminate 
between good and bad performing roof structures, and that the occupant 
kinematics and roof crush during dynamic rollover were unrepeatable. 
The agency is unaware of any dynamic test procedures that provide a 
sufficiently repeatable test environment. Finally, we believe quasi-
static testing adequately represent real world dynamic deformation 
patterns occurring in rollovers.
---------------------------------------------------------------------------

    \87\ For more details on the inverted drop test evaluation 
please see Section VII(C)(1), and Glen C. Rains and Mike Van 
Voorhis, ``Quasi Static and Dynamic Roof Crush Testing,'' DOT HS 
808-873, 1998.
---------------------------------------------------------------------------

    For the reasons discussed above and in Section VI(C)(1), NHTSA is 
withdrawing the open rulemaking on the Hogan petition. Instead, the 
agency proposes to adopt the new roof strength requirements discussed 
elsewhere in this document.

B. Agency Response to Ford and RVIA Petition

    On June 11, 1999, Ford \88\ and RVIA \89\ submitted petitions for 
reconsideration to the April 27, 1999, final rule (64 FR 22567), which 
established the primary and secondary test plate positioning procedures 
specified in S7.3 and S7.4, respectively. Petitioners argued that the 
secondary plate positioning test procedure produced rear edge plate 
loading onto the roof of some raised and altered roof vehicles that 
caused excessive deformation uncharacteristic of real-world rollover 
crashes. Specifically, petitioners argued that positioning the test 
plate such that the rear edge of the plate is at the rearmost point of 
the front occupant area resulted in stress concentration, which 
produced excessive deformation and roof penetration. Petitioners 
stressed that this type of loading is uncommon to real-world rollovers. 
Consequently, petitioners asked the agency to reconsider adopting the 
secondary plate positioning procedure for raised or altered roof 
vehicles. Ford also provided computer analysis that showed non-
distributed loading near the edge plate contact when the secondary 
plate position was used.
---------------------------------------------------------------------------

    \88\ Docket No. NHTSA-99-5572-2 (http://dmses.dot.gov/docimages/pdf37/57806_web.pdf).
    \89\ Docket No. NHTSA-99-5572-3 (http://dmses.dot.gov/docimages/pdf39/62547_web.pdf).
---------------------------------------------------------------------------

    As discussed in Section VII(C)(4), the agency is proposing to 
eliminate the secondary test procedure (49 CFR Sec.  571.216, S7.4) and 
to require that all vehicles subject to FMVSS No. 216 use the primary 
test procedure in S7.3. Specifically, all vehicles would be tested such 
that the midpoint of the forward edge of the lower surface of the test 
plate is within 10 mm (0.4 inches) of the transverse vertical plane 254 
mm (10 inches) forward of the forwardmost point on the exterior surface 
of the roof.

C. Request for Comments on Advanced Restraints

    In evaluating the effectiveness of seat belt restraints in 
mitigating rollover-related injury, NHTSA developed a rollover test 
device, the ``rollover restraints tester'' (RRT).\90\ RRT was used to 
simulate rollover conditions and evaluate the effectiveness of: (1) 
Typical 3-point lap and shoulder belt system; (2) D-ring \91\ 
adjustments, (3) belt pretensioners; (4) integrated seats; \92\ and (5) 
inflatable tubular torso restraint (ITTR) in preventing occupant 
excursion in a rollover event.\93\
---------------------------------------------------------------------------

    \90\ See http://www-nrd.nhtsa.dot.gov/pdf/nrd-01/Esv/esv16/98S8W34.PDF.
    \91\ D-ring is the upper anchorage of the three-point seat belt 
assembly.
    \92\ An integrated seat is a seat that includes the seat belt 
mechanism and assembly in the seat instead of on the B-pillar.
    \93\ Rains, Glen C., et al., ``Evaluation of Restraints 
Effectiveness in Simulated Rollover Conditions,'' 16th International 
Technical Conference on the Enhanced Safety of Vehicles, 98-S8-W-34, 
Windsor, Canada, 1998.
---------------------------------------------------------------------------

    Following testing, we arrived at the following conclusions: (1) The 
maximum head excursion was much higher during the test (when dummy was 
upside down in the restraint), compared to static pre- and post-test 
head excursion measurements; (2) raising the D-ring decreased the dummy 
head vertical and horizontal excursion

[[Page 49242]]

in both 3-point lap and shoulder belt system and ITTR; (3) compared to 
conventional seats, the integrated seat significantly reduced occupant 
excursion; (4) initiating belt pretensioners before testing the 
integrated seat (thus simulating pre-rollover activation of the 
pretensioners) provided additional benefit; and (5) compared to a 
conventional lap and shoulder seat belt system, the ITTR more 
effectively restrained the vertical and longitudinal excursion of the 
dummy.
    In addition to the agency testing, several other studies indicate 
that pretensioned restraint systems can reduce the amount of vertical 
head excursion compared to the typical 3-point lap and shoulder belt 
system.\94\ By contrast, a Nissan study showed that the maximum 
occupant injury values in rollovers did not decrease for occupants with 
activated pretensioners, compared to occupants without 
pretensioners.\95\
---------------------------------------------------------------------------

    \94\ Pywell, James et al., ``Characterization of Belt Restraint 
Systems in Quasi-Static Vehicle Rollover Tests,'' SAE Paper 973334, 
Society of Automotive Engineers, Warrendale, PA, 1997; and Moffatt, 
Edward et al., ``Head Excursion of Seat Belted Cadaver, Volunteers 
and Hybrid III ATD in a Dynamic/Static Rollover Fixture,'' SAE Paper 
973347, Society of Automotive Engineers, Warrendale, PA, 1997.
    \95\ Hare, Barry et al., ``Analysis of Rollover Restraint 
Performance with and without Seat Belt Pretensioner at Vehicle 
Trip,'' SAE Paper 2002-01-0941, Society of Automotive Engineers, 
Warrendale, PA, 2002.
---------------------------------------------------------------------------

    In response to the October 2001 RFC, we received several 
suggestions with respect to enhancing occupant protection in rollover 
crashes by means of using better seat belts. Slavik suggested amending 
FMVSS Nos. 208 and 209 to require the use of pretensioners that 
activate in rollovers before the vehicle rolls 90-degrees, and 
retractors that lock and remain locked for at least five seconds after 
the pretensioner is fired. Syson-Hille and Associates stated that NHTSA 
should continue its efforts to increase seat belt use rates, and 
consider amending FMVSS Nos. 208, 209, and 210 to ensure that belts 
provide enhanced occupant protection and remain fastened in rollover 
crashes.
    On August 7, 2003, NHTSA met with representatives of the Automotive 
Occupant Restraints Council (AORC) to discuss seat belt technologies 
that have the potential for improving occupant protection in rollover 
crashes.\96\ AORC made a presentation entitled, ``Seat Belt 
Technologies Improving Occupant Protection in Rollover.'' In the 
presentation, AORC discussed several seat belt technologies including 
pretensioning systems, electric retractors, inflatable seat belts, and 
four-point harnesses.
---------------------------------------------------------------------------

    \96\ See Docket Number NHTSA 2003-14622-10.
---------------------------------------------------------------------------

    Since advanced restraints have the potential for contributing to 
the comprehensive effort to reduce rollover-related injuries and 
fatalities, the agency would like comments on the following issues:
    1. Could requiring advanced restraints systems on vehicles 
significantly reduce head excursion and decrease occupant injury values 
in rollovers?
    2. Which kinds of advanced restraints systems are the most 
effective at minimizing vertical occupant excursion during rollovers?
    3. What is the current state of technology with respect to 
pretensioning systems that are capable of activating in a rollover 
event as well as other crash modes? What are the associated costs?
    4. What procedures would be appropriate for testing performance of 
advanced seat belt systems? At what values should the pretension sensor 
activate?
    5. What would be an appropriate limit for the force exerted by a 
pretensioning system on an occupant and how would it be measured?

IX. Benefits

    The agency examined the relationship between injuries in rollover 
crashes and the amount of post-crash headroom and found a statistically 
significant relationship between injury rates and instances in which 
the roof intruded below the occupant's normal seating height. The 
injury patterns were less serious in cases in which roof intrusion did 
not encroach on the pre-crash headroom of the occupant; i.e., when the 
deformed roof structure did not intrude below the top of the seated 
occupant's head.
    Using two alternative analytical approaches, the agency prepared 
two estimates of safety benefits resulting from the proposed roof crush 
resistance upgrade. The second approach was developed to cure 
shortcomings in the first approach.
    Under the first approach, the agency analyzed specific cases of 
actual injuries and fatalities involving belted occupants that were not 
fully ejected during rollovers. Using FARS and NASS-CDS databases, we 
analyzed only those cases in which the roof intrusion occurred over the 
injured occupant's seat, and the MAIS was in fact caused by roof 
contact with the occupant. We sought to estimate how an injured or 
killed occupant in each specific case might have benefited from a 
stronger roof structure. The agency believes that this estimate is 
conservative since limiting roof crush might also benefit those 
occupants who have roof crush related injuries that are not MAIS. That 
is some occupants are injured as a result of roof crush, but their most 
severe injury resulted from something other than roof crush.
    Based on the first approach, the agency estimates that the proposed 
requirements would prevent 13 fatalities and 793 non-fatal injuries. We 
estimate 39 annual equivalent lives saved.
    We note, however, that because we narrowed the case sample to 
reflect specific crash characteristics, the agency has a very limited 
sample of relevant cases at its disposal. Further, some of the relevant 
cases within that sample lacked some data elements, resulting in data 
gaps. At the same time, certain individual cases were assigned very 
large sample weight by the NASS-CDS database. This distorted the 
overall profile of relevant injuries (case weight spikes). As a result, 
the agency believes that the characteristics of this limited sample may 
not accurately represent the full benefits resulting from the proposed 
roof crush resistance upgrade.
    Under the second approach, the agency again examined the same 
injury cases discussed in the first approach. However, in evaluating 
actual crashes, the agency noted that post-crash negative headroom \97\ 
measurements available from FARS and NASS-CDS databases were related to 
occupant's actual height. For example, the amount of post-crash 
headroom in a vehicle occupied by a taller person would be different 
from post-crash headroom of the same vehicle occupied by a shorter 
person.
    To better estimate how this proposal would benefit occupants of 
varying heights, the agency assumed that the probability of occupant 
height in each actual relevant rollover case would be equal to the 
national distribution of occupant heights. That is, an occupant of any 
size might have been involved in a crash that fits the agency's case 
criteria. We calculated the odds of the occupant in each case being of 
a height to benefit from the proposed requirements. This calculation 
differed for each rollover case based on amount of actual roof 
intrusion and vehicle design. As a result, the agency was able to use a 
more refined case sample to estimate the benefits of the proposed 
requirements. We were able to estimate how any occupant would benefit 
from stronger roofs in each actual crash case.

[[Page 49243]]

This approach minimized case weight spikes inherent to the first 
approach used to estimate potential benefits of this proposal.
    Under the second approach, the agency estimates that the proposed 
requirements would prevent 44 fatalities and 498 non-fatal injuries. We 
estimate 55 equivalent lives saved annually.
---------------------------------------------------------------------------

    \97\ Negative headroom means post-crash headroom that is below 
the occupant's seated height.
---------------------------------------------------------------------------

    We note however, that the second approach assumes a random 
relationship between the height of drivers and the headroom in vehicles 
that they purchase. The agency believes that the relationship between 
vehicle headroom and occupant size is insignificant in most cases. It 
is likely that taller drivers adjust the seat positions to prevent 
uncomfortable proximity to the roof.
    The agency requests comments on both approaches for estimating 
benefits of this proposal. A more detailed discussion of the estimated 
benefits associated with this proposal are in the PRIA.

X. Costs

    The agency estimates that upgrading the roof crush resistance 
standard would result in annual fleet costs of $88 to $95 million. The 
total fleet cost is based on structural changes and impacts on fuel 
economy. The average cost of strengthening the roof structure of 
vehicles that do not meet the proposed requirements is estimated to be 
$10.67 per vehicle, with an annual fleet cost of $58.6 million. We 
estimate that approximately 32 percent of the current vehicle fleet 
would need improvements to meet the proposed upgraded requirements. The 
average fuel economy impact cost is estimated to be $5.33 to $6.69 per 
vehicle, with an annual fleet cost of $29.4 to $36.9 million.
    We estimated the structural costs using finite element vehicle 
modeling in which various components of two vehicles that do not meet 
the proposed requirements were upgraded until the two vehicles met the 
proposed requirements, and roof crush tests of twenty recent model year 
vehicles. The two vehicles were a 1998 Plymouth Neon passenger car, and 
a 1999 Ford E-150 van. The initial baseline crush tests of the Neon and 
Ford E-150 showed that each vehicle could withstand a roof crush force 
of about 1.9 times its unloaded weight. Neither vehicle would comply 
with the proposed requirements because the roof over the front seat 
area cannot withstand a force of 2.5 times the unloaded vehicle weight.
    Through an iterative process, improvements were reflected within 
the finite element model until the Neon and E-150 could withstand a 
roof crush force of about 20 percent greater than 2.5 times their 
vehicle weight.\98\
---------------------------------------------------------------------------

    \98\ The agency assumes that manufacturers would design their 
vehicles so that they can meet a standard with a 20% compliance 
margin in order to address production and performance variability 
concerns. Vehicle manufacturers normally include compliance margins 
in their vehicle designs to assure that each vehicle could pass the 
applicable test requirements. In this case, a safety margin of 20 
percent would require that vehicles withstand applied force of 3 
times the unloaded vehicle weight (1.2 x 2.5).
---------------------------------------------------------------------------

    We estimate the price increase for the purchaser (consumer cost) to 
improve the Neon roof strength to 2.5 times the unloaded vehicle weight 
with a 20 percent compliance margin to be $3.02, and the consumer cost 
to improve the E-150 roof strength to 2.5 times the unloaded vehicle 
weight with a 20 percent compliance margin to be $29.66.\99\ Further, 
we estimated the average cost of strengthening the roof structure of 
vehicles that do not meet the proposed requirements to be $10.67.\100\
---------------------------------------------------------------------------

    \99\ These improvements include changes in the material strength 
(steel gage, for example) of various vehicle components.
    \100\ The consumer cost average estimate was weighted for 
relative roof strength of different vehicles and corresponding sales 
volumes.
---------------------------------------------------------------------------

    In addition to finite element vehicle modeling, the agency tested a 
representative sample of 20 recent model year vehicles to estimate what 
percentage of the overall fleet already complies with the proposed 
requirements. Based on the current sales data, these 20 vehicles 
represent a current vehicle fleet population of approximately 5.9 
million vehicles. Seven of the 20 vehicles tested by the agency failed 
the proposed roof crush resistance requirements. The seven failing 
vehicles represent a vehicle fleet population of approximately 1.9 
million. The cost of upgrading these 1.9 million vehicles would be 
$20.3 million.
    We estimate that 17 million new vehicles would be subject to the 
proposed requirements. Accordingly, before accounting for weight gain 
implications, we estimate the total fleet cost to be $58.6 million (17 
million / 5.9 million x $20.3 million).
    Additionally, the changes made to increase roof strength may 
require heavier materials and or reinforcements that could increase the 
weight of the vehicle. This weight increase may adversely affect the 
vehicle's fuel economy and thus increase the amount of fuel it consumes 
over its lifetime. We estimate that the average weight gain necessary 
to upgrade the roof crush resistance of the vehicle fleet of 17 million 
vehicles is 0.6 lbs per vehicle. We estimate that this added weight 
would result in additional fuel expenditures in the amount of $29.4 to 
$36.9 million per year, resulting in the total annual fleet costs of 
$88 to $95 million ($58.6 + $29.4) or ($58.6 + $36.9).\101\
---------------------------------------------------------------------------

    \101\ For details on the fuel economy impacts, please see the 
PRIA.
---------------------------------------------------------------------------

XI. Lead Time

    NHTSA proposes that the manufacturers be required to comply with 
the new requirements for FMVSS No. 216 on and after the first September 
1 that occurs more than three years (36 months) after the issuance of 
the final rule. Based on recent agency testing, the agency estimates 
that 68 percent of the current fleet already complies with the proposed 
roof strength requirements. Accordingly, the proposed roof strength 
requirements would not necessitate fleet-wide roof structure changes. 
NHTSA believes that vehicle manufacturers have engineering and 
manufacturing resources that would enable vehicles to meet the new 
requirements three years after the publication of the final rule. We 
request comments on the lead time necessary to comply with the proposal 
requirements.

XII. Request for Comments

How Do I Prepare and Submit Comments?

    Your comments must be written and in English. To ensure that your 
comments are correctly filed in the Docket, please include the docket 
number of this document in your comments. Your comments must not be 
more than 15 pages long.\102\ We established this limit to encourage 
you to write your primary comments in a concise fashion. However, you 
may attach necessary additional documents to your comments. There is no 
limit on the length of the attachments. Please submit two copies of 
your comments, including the attachments, to Docket Management at the 
address given above under ADDRESSES. Comments may also be submitted to 
the docket electronically by logging onto the Docket Management System 
Web site at http://dms.dot.gov. Click on ``Help & Information'' or 
``Help/Info'' to obtain instructions for filing the document 
electronically. If you are submitting comments electronically as a PDF 
(Adobe) file, we ask that the documents submitted be scanned using 
Optical Character Recognition (OCR) process, thus allowing the agency 
to search and

[[Page 49244]]

copy certain portions of your submissions.\103\
---------------------------------------------------------------------------

    \102\ See 49 CFR 553.21.
    \103\ Optical character recognition (OCR) is the process of 
converting an image of text, such as a scanned paper document or 
electronic fax file, into computer-editable text.
---------------------------------------------------------------------------

    Please note that pursuant to the Data Quality Act, in order for 
substantive data to be relied upon and used by the agency, it must meet 
the information quality standards set forth in the OMB and DOT Data 
Quality Act guidelines. Accordingly, we encourage you to consult the 
guidelines in preparing your comments. OMB's guidelines may be accessed 
at http://www.whitehouse.gov/omb/fedreg/reproducible.html. DOT's 
guidelines may be accessed at http://dmses.dot.gov/submit/DataQualityGuidelines.pdf.

How Can I Be Sure That My Comments Were Received?

    If you wish Docket Management to notify you upon its receipt of 
your comments, enclose a self-addressed, stamped postcard in the 
envelope containing your comments. Upon receiving your comments, Docket 
Management will return the postcard by mail.

How Do I Submit Confidential Business Information?

    If you wish to submit any information under a claim of 
confidentiality, you should submit three copies of your complete 
submission, including the information you claim to be confidential 
business information, to the Chief Counsel, NHTSA, at the address given 
above under FOR FURTHER INFORMATION CONTACT. In addition, you should 
submit two copies, from which you have deleted the claimed confidential 
business information, to Docket Management at the address given above 
under ADDRESSES. When you send a comment containing information claimed 
to be confidential business information, you should include a cover 
letter setting forth the information specified in our confidential 
business information regulation.\104\
---------------------------------------------------------------------------

    \104\ See 49 CFR Part 512.
---------------------------------------------------------------------------

Will the Agency Consider Late Comments?

    We will consider all comments that Docket Management receives 
before the close of business on the comment closing date indicated 
above under DATES. To the extent possible, we will also consider 
comments that Docket Management receives after that date. If Docket 
Management receives a comment too late for us to consider in developing 
a final rule (assuming that one is issued), we will consider that 
comment as an informal suggestion for future rulemaking action.

How Can I Read the Comments Submitted By Other People?

    You may read the materials placed in the docket for this document 
(e.g., the comments submitted in response to this document by other 
interested persons) by going to the street address given above under 
ADDRESSES. The hours of the Docket Management System (DMS) are 
indicated above in the same location.
    You may also read the materials on the Internet. To do so, take the 
following steps:
    (1) Go to the Web page of the Department of Transportation DMS 
(http://dms.dot.gov/search/searchFormSimple.cfm).
    (2) On that page type in the five-digit docket number cited in the 
heading of this document. After typing the docket number, click on 
``search.''
    (3) On the next page (``Docket Search Results''), which contains 
docket summary information for the materials in the docket you 
selected, scroll down and click on the desired materials. You may 
download the materials.

XIII. Rulemaking Analyses and Notices

A. Executive Order 12866 and DOT Regulatory Policies and Procedures

    NHTSA has considered the impact of this rulemaking action under 
Executive Order 12866 and the Department of Transportation's regulatory 
policies and procedures. The Office of Management and Budget reviewed 
this rulemaking document under E.O. 12866, ``Regulatory Planning and 
Review.'' This rulemaking action has been determined to be significant 
under Executive Order 12866 and the DOT Policies and Procedures because 
of Congressional and public interest. This rulemaking action is not 
economically significant because the estimated yearly costs do not 
exceed $100 million. The total estimated recurring fleet cost for all 
changes proposed by this document is $88 to $95 million. NHTSA is 
placing in the public docket a PRIA describing the costs and benefits 
of this rulemaking action.\105\ The costs and benefits are also 
summarized in Sections IX and X above. We estimate that, if adopted, 
this proposal would result in 13-44 fewer fatalities and 498-793 fewer 
non-fatal injuries each year.
---------------------------------------------------------------------------

    \105\ See Docket No. NHTSA-2005-22143.
---------------------------------------------------------------------------

B. Regulatory Flexibility Act

    The Regulatory Flexibility Act of 1980 (5 U.S.C. 601 et seq.) 
requires agencies to evaluate the potential effects of their proposed 
rules on small businesses, small organizations and small governmental 
jurisdictions. I have considered the possible effects of this 
rulemaking action under the Regulatory Flexibility Act and certify that 
it would not have a significant economic impact on a substantial number 
of small entities.
    Under 13 CFR 121.201, the Small Business Administration (SBA) 
defines small business (for the purposes of receiving SBA assistance) 
as a business with less than 750 employees. Most of the manufacturers 
of recreation vehicles, conversion vans, and specialized work trucks 
are small businesses that manufacture vehicles in two or more stages. 
Some of these manufacturers produce vehicles that would be subject to 
the proposed requirements, as their GVWR is less than or equal to 
10,000 pounds. While the number of these small businesses potentially 
affected by this proposal is substantial, the economic impact upon 
these entities will not be significant for the following reasons:
    1. As indicated in Section VII(A)(2), we are proposing to allow 
vehicles manufactured in two or more stages (other than chassis-cabs), 
to certify to the roof crush requirements of FMVSS No. 220, instead of 
FMVSS No. 216. This aspect of our proposal will afford significant 
economic relief to small businesses because some of them are already 
required by the States to certify to the requirements of FMVSS No. 220. 
Thus, the proposal would not require additional expenditure by these 
small businesses.
    2. Small businesses using chassis cabs would be in position to take 
advantage of ``pass-through certification,'' and therefore, are not 
expected to incur any additional expenditures.
    3. We believe that some of the vehicles manufactured by these small 
businesses already comply with the proposed requirements.\106\
---------------------------------------------------------------------------

    \106\ As discussed in Section X above, 68% of the current fleet 
meets the proposed requirements.
---------------------------------------------------------------------------

    In addition to small businesses that manufacture vehicles in two or 
more stages, there are four manufacturers of passenger cars that are 
small businesses.\107\ All of these manufacturers could be affected by 
the proposed requirements. However, the economic impact upon these 
entities will not be significant for the following reasons.
---------------------------------------------------------------------------

    \107\ Avanti, Panoz, Saleen, Shelby.
---------------------------------------------------------------------------

    1. While the average cost for roof crush resistance upgrades was 
estimated at approximately $12 per vehicle, the cost of upgrading the 
roof structures of

[[Page 49245]]

passenger cars is lower because we believe that this cost is a function 
of weight of the vehicle. For example, the cost of upgrading the roof 
structure of Dodge Neon, a passenger vehicle, was estimated at $3.
    2. The agency believes that a cost increase of $3 to $12 would not 
have a significant economic impact upon small businesses that 
manufacture passenger cars because these costs can be passed onto the 
consumer. This increase would represent, at most, less than one-half of 
one tenth of a percent of the least expensive vehicle manufactured by 
the four entities.\108\
---------------------------------------------------------------------------

    \108\ Approximately $25,000.
---------------------------------------------------------------------------

    3. We believe that some of the vehicles manufactured by these small 
businesses already comply with the proposed requirements.\109\
---------------------------------------------------------------------------

    \109\ As discussed in Section X above, 68% of the current fleet 
meets the proposed requirements. We believe this may be especially 
true for high performance vehicles typically manufactured by small 
businesses.
---------------------------------------------------------------------------

    4. Some of the vehicles manufactured by these small businesses are 
convertibles not subject to this proposal.

C. National Environmental Policy Act

    NHTSA has analyzed this proposal for the purposes of the National 
Environmental Policy Act. The agency has determined that implementation 
of this action would not have any significant impact on the quality of 
the human environment. Upgrading the roof crush resistance standard may 
impact the weight of the vehicles subject to that standard and 
consequently result in the reduced fuel economy for these vehicles. 
However, the agency believes that the resulting impact on environment 
will be insignificant. A full discussion of fuel economy implications 
is in the PRIA.

D. Executive Order 13132 (Federalism)

    The agency has analyzed this rulemaking in accordance with the 
principles and criteria contained in Executive Order 13132 and has 
determined that it does not have sufficient federal implications to 
warrant consultation with State and local officials or the preparation 
of a federalism summary impact statement. The proposal would not have 
any substantial impact on the States, or on the current Federal-State 
relationship, or on the current distribution of power and 
responsibilities among the various local officials.

E. Unfunded Mandates Act

    The Unfunded Mandates Reform Act of 1995 requires agencies to 
prepare a written assessment of the costs, benefits and other effects 
of proposed or final rules that include a Federal mandate likely to 
result in the expenditure by State, local or tribal governments, in the 
aggregate, or by the private sector, of more than $100 million annually 
($120.7 million as adjusted annually for inflation with base year of 
1995). The assessment may be combined with other assessments, as it is 
here.
    This proposal is not likely to result in expenditures by State, 
local or tribal governments or automobile manufacturers and/or their 
suppliers of more than $120.7 million annually. The agency estimates 
that upgrading the roof crush resistance standard would result in 
annual fleet costs of $88 to $95 million. No expenditures by State, 
local or tribal governments are expected. A full assessment of the 
rule's costs and benefits is provided in the PRIA.

F. Civil Justice Reform

    This NPRM would not have any retroactive effect. 49 U.S.C. 30161 
sets forth a procedure for judicial review of final rules establishing, 
amending, or revoking Federal motor vehicle safety standards. That 
section does not require submission of a petition for reconsideration 
or other administrative proceedings before parties may file suit in 
court.
    State action on safety issues within the purview of a Federal 
agency may be limited or even foreclosed by express language in a 
congressional enactment, by implication from the depth and breadth of a 
congressional scheme that occupies the legislative field, or by 
implication because of a conflict with a congressional enactment. In 
this regard, we note that section 30103(b) of 49 U.S.C. provides, 
``When a motor vehicle safety standard is in effect under this chapter, 
a State or a political subdivision of a State may prescribe or continue 
in effect a standard applicable to the same aspect of performance of a 
motor vehicle or motor vehicle equipment only if the standard is 
identical to the standard prescribed under this chapter.'' Thus, all 
differing state statutes and regulations would be preempted.
    Further, it is our tentative judgment that safety would best be 
promoted by the careful balance we have struck in this proposal among a 
variety of considerations and objectives regarding rollover safety. As 
discussed above, this proposal is a part of a comprehensive plan for 
reducing the serious risk of rollover crashes and the risk of death and 
serious injury in those crashes. The objective of this proposal is to 
increase the requirement for roof crush resistance only to the extent 
that it can be done without negatively affecting vehicle dynamics and 
rollover propensity. The agency has tentatively concluded that our 
proposal would not adversely affect vehicle dynamics and cause vehicles 
to become more prone to rollovers. In contrast, the agency believes 
that either a broad State performance requirement for greater levels of 
roof crush resistance or a narrower requirement mandating that 
increased roof strength be achieved by a particular specified means, 
would frustrate the agency's objectives by upsetting the balance 
between efforts to increase roof strength and reduce rollover 
propensity.
    Increasing current roof crush resistance requirements too much 
could potentially result in added weight to the roof and pillars, 
thereby increasing the vehicle center of gravity (CG) height and 
rollover propensity. In order to avoid this, we sought to strike a 
careful balance between improving roof crush resistance and potentially 
negative effects of too large an increase upon the vehicle's rollover 
propensity.
    We recognize that there is a variety of potential ways to increase 
roof crush resistance beyond the proposed level. However, we believe 
that any effort to impose either more stringent requirements or 
specific methods of compliance would frustrate our balanced approach to 
preventing rollovers from occurring as well as the deaths and injuries 
that result when rollovers nevertheless occur.
    First, we believe that requiring a more stringent level of roof 
crush resistance for all vehicles could increase rollover propensity of 
many vehicles and thereby create offsetting adverse safety 
consequences. While the agency is aware of at least several current 
vehicle models that provide greater roof crush resistance than would be 
required under our proposal, requiring greater levels of roof crush 
resistance for all vehicles could, depending on the methods of 
construction and materials used, and on other factors, render other 
vehicles more prone to rollovers, thus frustrating the agency's 
objectives in this rulemaking.
    Second, we believe that requiring vehicle manufacturers to improve 
roof crush resistance by a specific method would also frustrate agency 
goals. The optimum methods for addressing the risks of rollover crashes 
vary considerably for different vehicles, and requiring specific 
methods for improving roof crush resistance could interfere with the 
efforts to develop optimal solutions. Moreover, some methods of 
improving roof crush resistance are costlier than others. The resources 
diverted to increasing roof strength using one of the costlier

[[Page 49246]]

methods could delay or even prevent vehicle manufacturers from 
equipping their vehicles with advanced vehicle technologies for 
reducing rollovers, such as Electronic Stability Control.
    Based on the foregoing, if the proposal were adopted as a final 
rule, it would preempt all conflicting State common law requirements, 
including rules of tort law.

G. National Technology Transfer and Advancement Act

    Under the National Technology Transfer and Advancement Act of 1995 
(NTTAA) (Pub. L. 104-113), ``all Federal agencies and departments shall 
use technical standards that are developed or adopted by voluntary 
consensus standards bodies, using such technical standards as a means 
to carry out policy objectives or activities determined by the agencies 
and departments.'' As discussed in Section V, we evaluated the Society 
of Automotive Engineers (SAE) inverted drop testing procedure, but 
decided against proposing it. We were unable to identify any other 
relevant technical standards. The agency requests comments on other 
relevant technical standards.

H. Paperwork Reduction Act

    Under the Paperwork Reduction Act of 1995 (PRA) (44 U.S.C. 3501, et 
seq.), Federal agencies must obtain approval from the Office of 
Management and Budget (OMB) for each collection of information they 
conduct, sponsor, or require through regulations. NHTSA has reviewed 
this proposal and determined that it does not contain collection of 
information requirements.

I. Plain Language

    Executive Order 12866 requires each agency to write all rules in 
plain language. Application of the principles of plain language 
includes consideration of the following questions:
     Have we organized the material to suit the public's needs?
     Are the requirements in the rule clearly stated?
     Does the rule contain technical language or jargon that 
isn't clear?
     Would a different format (grouping and order of sections, 
use of headings, paragraphing) make the rule easier to understand?
     Would more (but shorter) sections be better?
     Could we improve clarity by adding tables, lists, or 
diagrams?
     What else could we do to make the rule easier to 
understand?
    If you have any responses to these questions, please include them 
in your comments on this proposal.

J. Privacy Act

    Anyone is able to search the electronic form of all comments 
received into any of our dockets by the name of the individual 
submitting the comment (or signing the comment, if submitted on behalf 
of an association, business, labor union, etc.). You may review DOT's 
complete Privacy Act Statement in the Federal Register published on 
April 11, 2000 (Volume 65, Number 70; Pages 19477-78) or you may visit 
http://dms.dot.gov.

XVI. Vehicle Safety Act

    Under 49 U.S.C. Chapter 301, Motor Vehicle Safety (49 U.S.C. 30101 
et seq.), the Secretary of Transportation is responsible for 
prescribing motor vehicle safety standards that are practicable, meet 
the need for motor vehicle safety, and are stated in objective 
terms.\110\ ``Motor vehicle safety standard'' means a minimum 
performance standard for motor vehicles or motor vehicle equipment. 
When prescribing such standards, the Secretary must consider all 
relevant, available motor vehicle safety information.\111\ The 
Secretary must also consider whether a proposed standard is reasonable, 
practicable, and appropriate for the types of motor vehicles or motor 
vehicle equipment for which it is prescribed and the extent to which 
the standard will further the statutory purpose of reducing traffic 
accidents and associated deaths.\112\ The responsibility for 
promulgation of Federal motor vehicle safety standards is delegated to 
NHTSA.
---------------------------------------------------------------------------

    \110\ 49 U.S.C. 30111(a).
    \111\ 49 U.S.C. 30111(b).
    \112\ Id.
---------------------------------------------------------------------------

    In proposing to improve roof crush resistance, the agency carefully 
considered these statutory requirements.
    First, we believe that this proposal will meet the need for motor 
vehicle safety because the proposed applied force requirement would 
lead to stronger roofs and reduce the roof crush severity observed in 
real world crashes, thus better protecting front seat occupants.
    Second, we believe that the roof crush resistance standard subject 
of this proposal is performance oriented because it requires only that 
the vehicle roof be able to withstand a certain amount of applied 
force. The standard does not specify the means by which the vehicle 
must meet the standard.
    Third, this proposal was preceded by a Request for Comments, which 
facilitated the efforts of the agency to obtain and consider relevant 
motor vehicle safety information. We anticipate receiving an even more 
comprehensive array of relevant information in response to this 
proposal. Further, in preparing this document, the agency carefully 
evaluated previous agency research and vehicle testing that was 
relevant to this proposal. We also conducted additional testing in 
support of this document. Finally, the agency conducted a detailed 
statistical analysis in order to estimate risks of death or injury 
associated with roof crush, and to determine the relevant target 
population and potential costs and benefits of our proposal. In sum, 
this document reflects our consideration of all relevant, available 
motor vehicle safety information.
    Fourth, to ensure that requiring greater roof crush resistance is 
practicable, the agency tested a number of vehicles and found that many 
already comply with the proposed requirements, while others could 
comply with relatively inexpensive modifications to their roof 
structure. In response to the request for comments, the agency received 
no indication that the proposed roof crush resistance requirements were 
impracticable. However, based on the latest information from the 
manufacturers and our own testing, we are proposing to amend the test 
procedure for vehicles with raised or altered roofs to provide 
additional assurance of practicability.\113\ To improve practicability 
still further, the agency also proposes to revise the tie-down 
procedure. Because we are especially concerned with practicability of 
this proposal as it applies to vehicles manufactured in two or more 
stages, we are proposing to allow the certification of these vehicles 
to the roof crush requirements of FMVSS No. 220. In sum, we believe 
that this proposal to improve roof crush resistance is practicable.
---------------------------------------------------------------------------

    \113\ The agency previously adopted a ``secondary'' test 
procedure for vehicles with raised or altered roofs which proved to 
be an impracticable solution.
---------------------------------------------------------------------------

    Fifth, the proposed regulatory text following this preamble is 
stated in objective terms in order to specify precisely what 
performance is required and how performance will be tested to ensure 
compliance with the standard. Specifically, a large steel test plate 
would be forced down onto the roof of a vehicle. If the displaced roof 
structure does not contact the head or neck of the dummy seated inside 
the vehicle, the vehicle passes the test. The agency believes that this 
test procedure is sufficiently objective and would not result in any 
uncertainty as to whether a given vehicle satisfies the proposed roof 
crush resistance requirements.

[[Page 49247]]

    Finally, we believe that this proposal is reasonable and 
appropriate for motor vehicles subject to the proposed requirements. As 
discussed elsewhere in this notice, the agency is concerned with the 
amount of fatalities and serious injuries resulting from rollovers. Our 
statistical data indicate that vehicles subject to the proposed 
requirements are involved in rollovers that cause death and serious 
injury. Accordingly, we believe that this proposal is appropriate for 
vehicles that are or would become subject to FMVSS No. 216 because it 
furthers the agency's objective of preventing deaths and serious 
injuries associated with roof crush occurring in some of the rollovers.

XV. Proposed Regulatory Text

List of Subjects in 49 CFR Part 571

    Motor vehicle safety, Reporting and recordkeeping requirements, 
Tires.

    In consideration of the foregoing, NHTSA proposes to amend 49 CFR 
Part 571 as follows:

PART 571--[AMENDED]

    1. The authority citation of Part 571 would continue to read as 
follows:

    Authority: 49 U.S.C. 322, 2011, 30115, 30166 and 30177; 
delegation of authority at 49 CFR 1.50.

    2. Section 571.216 would be amended by:
    a. Revising S3 to read as set forth below;
    b. Adding to S4, in alphabetical order, new definitions of 
``Convertible'' and ``Roof component;''
    c. Revising S5 to read as set forth below;
    d. Removing S5.1;
    e. Revising S7.1 through S7.6 to read as set forth below; and
    f. Removing S8 through S8.4.
    The revisions and additions read as follows:


Sec.  571.216  Standard No. 216; Roof crush resistance.

* * * * *
    S3. Application. This standard applies to passenger cars, and to 
multipurpose passenger vehicles, trucks and buses with a GVWR of 4,536 
kilograms (10,000 pounds) or less. However, it does not apply to--
    (a) School buses;
    (b) Vehicles that conform to the rollover test requirements (S5.3) 
of Standard No. 208 (Sec.  571.208) by means that require no action by 
vehicle occupants;
    (c) Convertibles, except for optional compliance with the standard 
as an alternative to the rollover test requirement (S5.3) of Standard 
No. 208; or
    (d) Vehicles manufactured in two or more stages, other than chassis 
cabs, that conform to the roof crush requirements (S4) of Standard No. 
220 (Sec.  571.220).
    S4. Definitions.
* * * * *
    Convertible means a vehicle whose A-pillars are not joined with the 
B-pillars (or rearmost pillars) by a fixed, rigid structural member.
* * * * *
    Roof component means the A-pillar, B-pillar, roof side rail, front 
header, rear header, roof, and all interior trim in contact with these 
components.
* * * * *
    S5. Requirements. When the test device described in S6 is used to 
apply a force to either side of the forward edge of a vehicle's roof in 
accordance with S7, no roof component or portion of the test device may 
contact the head or the neck of the seated Hybrid III 50th percentile 
male dummy specified in 49 CFR Part 572, Subpart E. The maximum applied 
force in Newtons is at least 2.5 times the unloaded vehicle weight of 
the vehicle, measured in kilograms and multiplied by 9.8. A particular 
vehicle need not meet the requirements on the second side of the 
vehicle, after being tested at one location.
* * * * *
    S7.1 Secure the vehicle in accordance with S7.1(a) through (d).
    (a) Support the vehicle off its suspension at a longitudinal 
vehicle attitude of 0 degrees  0.5 degrees. Measure the 
longitudinal vehicle attitude along both the driver and passenger sill. 
Determine the lateral vehicle attitude by measuring the vertical 
distance between a level surface and a standard reference point on the 
bottom of the driver and passenger side sills. The difference between 
the vertical distance measured on the driver side and the passenger 
side sills shall not exceed  1 cm.
    (b) Secure the vehicle with four stands. The locations for 
supporting the vehicle are defined in S7.1(c) or (d). Welding is 
permissible. The vehicle overhangs are not supported. Chains and wire 
rope are not used to secure the vehicle. Fix all non-rigid body mounts 
to prevent motion of the body relative to the frame. Close all windows, 
close and lock all doors, and secure any moveable or removable roof 
structure in place over the occupant compartment. Remove roof racks or 
other non-structural components.
    (c) For vehicles with manufacturer's designated jacking locations, 
locate the stands at or near the specified location.
    (d) For vehicles with undefined jacking locations, generalized 
jacking areas, or jacking areas that are not part of the vehicle body 
or frame, such as axles or suspension members, locate two stands in the 
region forward of the rearmost axle and two stands rearward of the 
forwardmost axle. All four stands shall be located between the axles on 
either the vehicle body or vehicle frame.
    S7.2(a) Adjust the seats and steering controls in accordance with 
S8.1.2 and S.8.1.4 of 49 CFR 571.208.
    (b) Place adjustable seat backs in the manufacturer's nominal 
design riding position in the manner specified by the manufacturer. 
Place any adjustable anchorages at the manufacturer's nominal design 
position for a 50th percentile adult male occupant. Place each 
adjustable head restraint in its lowest adjustment position. Adjustable 
lumbar supports are positioned so that the lumbar support is in its 
lowest adjustment position.
    S7.3 Position the Hybrid III 50th percentile male dummy specified 
in 49 CFR Part 572, Subpart E in accordance with S10.1 through 
S10.6.2.2 of 49 CFR 571.208, in the front outboard designated seating 
position on the side of the vehicle being tested.
    S7.4 Orient the test device as shown in Figure 1 of this section, 
so that--
    (a) Its longitudinal axis is at a forward angle (in side view) of 5 
degrees below the horizontal, and is parallel to the vertical plane 
through the vehicle's longitudinal centerline;
    (b) Its transverse axis is at an outboard angle, in the front view 
projection, of 25 degrees below the horizontal.
    S7.5 Maintaining the orientation specified in S7.4--
    (a) Lower the test device until it initially makes contact with the 
roof of the vehicle.
    (b) Position the test device so that--
    (1) The longitudinal centerline on its lower surface is within 10 
mm of the initial point of contact, or on the center of the initial 
contact area, with the roof; and
    (2) The midpoint of the forward edge of the lower surface of the 
test device is within 10 mm of the transverse vertical plane 254 mm 
forward of the forwardmost point on the exterior surface of the roof, 
including windshield trim, that lies in the longitudinal vertical plane 
passing through the vehicle's longitudinal centerline.
    S7.6 Apply force so that the test device moves in a downward 
direction perpendicular to the lower surface of

[[Page 49248]]

the test device at a rate of not more than 13 millimeters per second 
until reaching the force level specified in S5. Guide the test device 
so that throughout the test it moves, without rotation, in a straight 
line with its lower surface oriented as specified in S7.4(a) and 
S7.4(b). Complete the test within 120 seconds.
* * * * *

    Issued: July 15, 2005.
Stephen R. Kratzke,
Associate Administrator for Rulemaking.
[FR Doc. 05-16661 Filed 8-19-05; 8:45 am]
BILLING CODE 4910-59-U