[Federal Register Volume 72, Number 86 (Friday, May 4, 2007)]
[Rules and Regulations]
[Pages 25484-25524]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 07-2011]



[[Page 25483]]

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Part III





Department of Transportation





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National Highway Traffic Safety Administration



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49 CFR Parts 571 and 585



 Federal Motor Vehicle Safety Standards; Head Restraints; Final Rule

  Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and 
Regulations  

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 571 and 585

[Docket No. NHTSA-2007-27986]
RIN 2127-AJ96


Federal Motor Vehicle Safety Standards; Head Restraints

AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT.

ACTION: Final rule; response to petitions for reconsideration.

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SUMMARY: This document completes the agency's response to petitions for 
reconsideration of the December 2004 final rule upgrading our head 
restraints standard. We are partially granting and partially denying 
the petitions.
    We are making two changes related to the backset requirement. 
First, to address concerns about variability in measurements, we are 
specifying that backset is determined by taking the arithmetic average 
of three measurements, rather than using a single measurement. Second, 
we are slightly relaxing the backset requirement by specifying that the 
55 mm backset limit applies with the seat back at the vehicle 
manufacturer's specified design angle rather than at 25 degrees. This 
decision reflects consideration of interrelated issues and data 
concerning the 55 mm backset limit, consumer comfort, and seat back 
angle.
    In addition, we are making a number of other amendments. We are 
making changes related to non-use positions of rear seat head 
restraints, requirements for gaps between the head restraint and seat 
back, and the backset and height retention (lock) tests, as well as a 
number of changes in other areas. For the front seat requirements, we 
are providing one additional year of leadtime and also establishing a 
one-year phase-in with an 80 percent requirement. The agency previously 
delayed the compliance date for voluntarily installed rear outboard 
head restraints by two years. In this document, we are also 
establishing a one-year 80 percent phase-in for those requirements. 
Finally, we respond to a petition for rulemaking concerning 
requirements included in the upgraded head restraints rule.
    Today's amendments will not affect the costs of the December 2004 
final rule. However, the agency estimates that the change in seat back 
angle to provide greater flexibility with respect to backset will 
result in a 20 percent reduction in the number of whiplash injuries 
prevented by upgraded front seat head restraints, compared to the 
benefits estimated in the December 2004 final rule. Whiplash injuries 
are Abbreviated Injury Scale (AIS) 1 injuries.
    The agency has separately been leading efforts to develop a Global 
Technical Regulation (GTR) on head restraints, under the United Nations 
Economic Commission for Europe 1998 Global Agreement. Some issues 
raised by petitioners for reconsideration, including ones related to 
backset and testing of dynamic systems, are also being discussed in the 
context of the GTR. While it is necessary for us to issue today's 
decision in order to respond to the outstanding petitions for 
reconsideration, we note that if agreement is achieved on the GTR, we 
will consider making changes in these and other areas.

DATES: Effective Date: This rule is effective July 3, 2007.
    Petitions: Petitions for reconsideration must be received by June 
18, 2007.

ADDRESSES: Petitions for reconsideration should refer to the docket 
number and be submitted to: Administrator, Room 5220, National Highway 
Traffic Safety Administration, 400 Seventh Street, SW., Washington, DC 
20590. Please see the Privacy Act heading under Regulatory Notices.

FOR FURTHER INFORMATION CONTACT: For non-legal issues, you may contact 
Louis Molino of the Office of Rulemaking, Office of Crashworthiness 
Standards, Light Duty Vehicle Division, NVS-112, (Phone: 202-366-2264; 
Fax: 202-366-4329; E-mail: [email protected]).
    For legal issues, you may contact Edward Glancy of the Office of 
Chief Counsel, NCC-112, (Phone: 202-366-2992; Fax 202-366-3820).
    You may send mail to both of these officials at the National 
Highway Traffic Safety Administration, 400 7th Street, SW., Washington, 
DC 20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Background
    A. Current Head Restraints
    B. The Safety Concern--Whiplash Injuries
    C. Understanding Whiplash
    D. Previous Regulatory Approach
    E. Current Knowledge
    F. January 2001 Notice of Proposed Rulemaking
    G. December 2004 Final Rule
II. Petitions for Reconsideration
III. Development of Global Technical Regulation on Head Restraints
IV. March 2006 Partial Response to Petitions
V. Overview of Decision
VI. Response to Petitions
    A. Backset Requirement
    B. Rear Seat Non-Use Positions
    C. Dynamic Option
    D. Clarification of Removability Requirement
    E. Height Requirement
    F Gaps Between Head Restraint and Seat Back
    G. Backset and Height Retention (Lock) Tests
    H. Energy Absorption Test and Seat Back Bracing
    I. Head Restraint Clearance
    J. Width of Head Restraints for Certain Seats
    K. Option To Comply With ECE 17
    L. Temperature and Humidity Specifications
    M. Owner's Manual Requirements
    N. Nature of Standard
    O. Leadtime
    P. Technical Amendments and Typographical Corrections
VII. Kongsberg Petition for Rulemaking
    A. Summary of Petition
    B. Effective Backset
    C. Backset Retention and Displacement
    D. Height Retention
    E. Non-Use Position
    F. Definition of Rear Head Restraint
    G. Gaps
    H. Removability of Head Restraints
VIII. Rulemaking Analyses and Notices

I. Background

    On December 14, 2004, NHTSA published in the Federal Register (69 
FR 74848) a final rule \1\ upgrading NHTSA's head restraint standard in 
order to reduce whiplash injuries in rear collisions. For front seat 
head restraints, the final rule provided that the upgraded standard 
becomes mandatory for all vehicles manufactured on or after September 
1, 2008. For head restraints voluntarily installed in rear outboard 
designated seating positions, the requirements become mandatory on 
September 1, 2010.\2\ In this section, we discuss the highlights of the 
December 2004 rule, and the safety concerns and other considerations 
that led the agency to adopt it.
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    \1\ Docket No. NHTSA-2004-19807.
    \2\ The September 1, 2010 date was established in a final rule; 
partial response to petitions for reconsideration published in the 
Federal Register (46 FR 12145) on March 9, 2006.
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A. Current Head Restraints

    Vehicle manufacturers currently use three types of head restraints 
to meet the requirements of FMVSS No. 202. The first type is the 
``integral head restraint,'' which is non-adjustable and is built into 
the seat. It typically consists of a seat back that extends high enough 
to meet the height requirement of the standard. The second type is the 
``adjustable'' head restraint, which consists of a separate cushion 
that is attached to the seat back, typically by two sliding metal 
shafts. Adjustable head restraints

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typically adjust vertically to accommodate different occupant seating 
heights. Some also provide adjustments to allow the head restraint to 
be moved closer to the occupant's head. The third type is the active 
head restraint system, which deploys in the event of a collision to 
minimize the potential for whiplash. During the normal vehicle 
operation, the active head restraint system is retracted.

B. The Safety Concern--Whiplash Injuries

    Whiplash injuries are a set of common symptoms that occur in motor 
vehicle crashes and involve the soft tissues of the head, neck and 
spine. Symptoms of pain in the head, neck, shoulders, and arms may be 
present along with damage to muscles, ligaments and vertebrae, but in 
many cases lesions are not evident. The onset of symptoms may be 
delayed and may only last a few hours; however, in some cases, effects 
of the injury may last for years or even be permanent. The relatively 
short-term symptoms are associated with muscle and ligament trauma, 
while the long-term ones are associated with nerve damage.
    Based on National Automotive Sampling System (NASS) data, we 
estimate that between 1988 and 1996, 805,581 whiplash injuries \3\ 
occurred annually in crashes involving passenger cars and LTVs (light 
trucks, multipurpose passenger vehicles, and vans). Of these whiplash 
injuries, 272,464 occurred as a result of rear impacts. For rear impact 
crashes, the average cost of whiplash injuries in 2002 dollars is 
$9,994 (which includes $6,843 in economic costs and $3,151 in quality 
of life impacts, but not property damage), resulting in a total annual 
cost of approximately $2.7 billion.
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    \3\ Non-contact Abbreviated Injury Scale (AIS) 1 neck.
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C. Understanding Whiplash

    Although whiplash injuries can occur in any kind of crash, an 
occupant's chances of sustaining this type of injury are greatest in 
rear-end collisions. When a vehicle is struck from behind, typically 
several things occur in quick succession to an occupant of that 
vehicle. First, from the occupant's frame of reference, the back of the 
seat moves forward into his or her torso, straightening the spine and 
forcing the head to rise vertically. Second, as the seat pushes the 
occupant's body forward, the unrestrained head tends to lag behind. 
This causes the neck to change shape, first taking on an S-shape and 
then bending backward. Third, the forces on the neck accelerate the 
head, which catches up with--and, depending on the seat back stiffness 
and if the occupant is using a shoulder belt, passes--the restrained 
torso. This motion of the head and neck, which is like the lash of a 
whip, gives the resulting neck injuries their popular name.

D. Previous Regulatory Approach

    As discussed in the NPRM preceding the December 2004 final rule, a 
historical examination of head restraint standards in this country 
indicates that the focus has been the prevention of neck hyperextension 
(the rearward movement of the head and neck over a large range of 
motion relative to the torso), as opposed to controlling lesser amounts 
of head and neck movement in a crash.
    The predecessor to FMVSS No. 202 was General Services 
Administration (GSA) Standard 515/22, which applied to vehicles 
purchased by the U.S. Government and went into effect on October 1, 
1967. GSA 515/22 required that the top of the head restraint achieve a 
height 700 mm (27.5 inches (in)) above the H-point.\4\ Also in 1967, 
research using staged 48 kilometer per hour (kph) (30 mile per hour, 
mph) crashes concluded that a head restraint 711 mm (28 in) above the 
H-point was adequate to prevent neck hyperextension of a 95th 
percentile male. FVMSS No. 202, which became effective on January 1, 
1969, required that head restraints be at least 700 mm (27.5 in) above 
the seating reference point or limit the relative angle between the 
head and the torso to 45 degrees or less during a dynamic test.
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    \4\ The H-point is defined by a test machine placed in the 
vehicle seat (Society of Automotive Engineers (SAE) J826, July 
1995). From the side, the H-point represents the pivot point between 
the torso and upper leg portions of the test machine. It can be 
thought of, roughly, as the hip joint of a 50th percentile male 
occupant viewed laterally.
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E. Current Knowledge

    There are many hypotheses as to the mechanisms of whiplash 
injuries. Despite a lack of consensus with respect to whiplash injury 
biomechanics, there is research indicating that reduced backset, i.e., 
the horizontal distance between the rear of the occupant's head and the 
head restraint, will result in reduced risk of whiplash injury. For 
example, one study of Volvo vehicles reported that, when vehicle 
occupants involved in rear crashes had their heads against the head 
restraint (an equivalent to 0 mm backset) during impact, no whiplash 
injury occurred.\5\ By contrast, another study showed significant 
increase in injury and duration of symptoms when an occupant's head was 
more than 100 mm away from the head restraint at the time of the rear 
impact.\6\
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    \5\ Jakobsson et al., Analysis of Head and Neck Responses in 
Rear End Impacts--A New Human-Like Model. Volvo Car Corporation 
Safety Report (1994).
    \6\ Olsson et al., An In-depth Study of Neck Injuries in Rear-
end Collisions. International IRCOBI Conference, pp 269-280 (1990).
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    In addition, the persistence of whiplash injuries in the current 
fleet of vehicles indicates that the existing height requirement is not 
sufficient to prevent excessive movement of the head and neck relative 
to the torso for some people. Specifically, the head restraints do not 
effectively limit rearward movement of the head of a person at least as 
tall as the average occupant. Research indicates that taller head 
restraints would better prevent whiplash injuries because at heights of 
750 to 800 mm, the head restraint can more effectively limit the 
movement of the head and neck.
    In a recent report from the Insurance Institute for Highway Safety 
(IIHS), Farmer, Wells, and Lund examined automobile insurance claims to 
determine the rates of neck injuries in rear end crashes for vehicles 
with the improved geometric fit of head restraints (reduced backset and 
increased head restraint height).\7\ Their data indicate that these 
improved head restraints are reducing the risk of whiplash injury. 
Specifically, there was an 18 percent reduction in injury claims. 
Similarly, NHTSA computer generated models have shown that the 
reduction of the backset and an increase in the height of the head 
restraint reduces the level of neck loading and relative head-to-torso 
motion that may be related to the incidence of whiplash injuries.\8\
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    \7\ Farmer, Charles, Wells, JoAnn, Lund, Adrian, ``Effects of 
Head Restraint and Seat Redesign on Neck Injury Risk in Rear-End 
Crashes,'' Insurance Institute For Highway Safety, October 2002.
    \8\ ``Effect of Head Restraint Position on Neck Injury in Rear 
Impact,'' World Congress of Whiplash-Associated Disorders (1999), 
Vancouver, British Columbia.
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    With respect to impact speeds, research and injury rate data 
indicate that whiplash may occur as a result of head and neck movements 
insufficient to cause hyperextension. Staged low speed impacts indicate 
that mild whiplash symptoms can occur without a person's head exceeding 
the normal range of motion. This means that our previous focus on 
preventing neck hyperextension is insufficient to adequately protect 
all rear impact victims from risks of whiplash injuries. Instead, to 
effectively prevent whiplash, the head restraint must control smaller

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amounts of rapid head and neck movement relative to the torso.
    In sum, in light of recent evidence that whiplash may be caused by 
smaller amounts of head and neck movements relative to the torso, and 
that reduced backset and increased height of head restraints help to 
better control these head and neck movements, we concluded that head 
restraints should be higher and positioned closer to the occupant's 
head in order to be more effective in preventing whiplash.
    Further, information about consumer practices regarding the 
positioning of adjustable head restraints indicates that there is a 
need to improve consumer awareness and knowledge of the importance of 
properly adjusted head restraints. Specifically, in 1995, NHTSA 
surveyed 282 vehicles to examine how well head restraints were adjusted 
and if the restraints should have been adjusted higher. Approximately 
50 percent of adjustable head restraints were left in the lowest 
adjustable position. Three quarters of these could have been raised to 
decrease whiplash potential by bringing the head restraint higher in 
relation to the center of gravity of the occupant's head. The 
information was included in a report \9\ for which the agency requested 
public comment. 61 FR 66992; December 19, 1996.
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    \9\ The report was included in Docket No. 96-22, Notice 1. It is 
noted that this NHTSA docket pre-dates the DOT DMS system.
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F. January 2001 Notice of Proposed Rulemaking

    Using the new information gained about the effectiveness of head 
restraints, on January 4, 2001, NHTSA published in the Federal Register 
(66 FR 968) a notice of proposed rulemaking (NPRM) to improve the 
effectiveness of head restraints. The agency proposed new height and 
backset requirements, and other requirements, described below. NHTSA 
also proposed that head restraints be required in the rear outboard 
seating positions.
    In the proposed FMVSS No. 202a, manufacturers were given the option 
of meeting either of two sets of requirements. The first set was a 
comprehensive group of dimension and strength requirements, compliance 
with which is measured statically. The second set was made of 
requirements that would have to be met in a dynamic test.\10\
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    \10\ The previous version of FMVSS No. 202 also features two 
sets of requirements; one applies to statically tested head 
restraints and the other to dynamically tested head restraints.
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1. Proposed Requirements for Head Restraints Tested Statically
    To ensure that head restraints would be properly used in a position 
high enough to limit hyperextension, the NPRM proposed the following 
height requirements. The top of the front integral head restraint would 
have to reach the height of at least 800 mm above the H-point. The top 
of the front adjustable head restraint would have to reach the height 
of at least 800 mm above the H-point, and could not be adjusted below 
750 mm. The top of the rear mandatory head restraint could be adjusted 
below 750 mm above the H-point. The NPRM also proposed that adjustable 
head restraints must lock in their adjustment positions. NHTSA proposed 
to retain existing requirements for head restraint width.\11\ To 
control even smaller amounts of rapid head and neck movement relative 
to the torso than the amount of relative motion resulting in neck 
hyperextension, the NPRM proposed also to limit the amount of backset 
to 50 mm (2 in) for both front and rear outboard head restraints. In 
addition, the NPRM also proposed maximum gap requirements for head 
restraint openings within the perimeter of the restraint, and for 
height adjustable head restraints, between the seat and head restraint.
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    \11\ 254 mm (10 in) for restraints on bench-type seats, and 171 
mm (6.75 in) for restraints on individual seats.
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    The agency also proposed to prohibit head restraints in the front 
seats from being removable solely by hand, i.e., without use of tools. 
Comments were requested on applying such a requirement to rear seat 
head restraints. Rear seat head restraints could be folded or retracted 
to ``non-use'' positions if they give the occupant an ``unambiguous 
physical cue'' that the restraint is not properly positioned by 
altering the normal torso angle of the seat occupant or automatically 
returning to a ``use'' position when the seat is occupied.
    In addition, the NPRM proposed that these statically-tested head 
restraints would have to meet a new energy absorption requirement, 
compliance with which would be measured using a free-motion impactor. 
Additionally, the agency proposed placing a minimum on the radius of 
curvature for the front surface of the vehicle seat and head restraint. 
The NPRM proposed modifications to the existing strength versus 
displacement test procedure to require simultaneous loading of the back 
pan \12\ and the head restraint, and to remove the allowance for seat 
back failure.
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    \12\ The back pan is the portion of the SAE J826 manikin (July 
1995) that comes in contact with the seat back. Its shape is 
intended to simulate the shape of an occupant's back and thus allow 
for a realistic load distribution.
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2. Proposed Requirements for Head Restraints Tested Dynamically
    The NPRM proposed a dynamic test alternative and said that the 
purpose was to ensure that the final rule does not discourage or 
preclude continuing development and implementation of active head 
restraints and other advanced seat back/head restraint systems designed 
to minimize rear impact injuries. Specifically, the NPRM proposed that 
head restraints tested dynamically would have to meet a Head Injury 
Criterion (HIC) limit of 150 with a 15 millisecond (ms) window. In 
addition, NHTSA proposed a head-to-torso rotation limit of 20 degrees 
when testing with a 95th percentile male dummy in front outboard seats, 
and of 12 degrees when testing with a 50th percentile male dummy in all 
outboard seats.\13\ Further, the NPRM proposed that the head restraints 
must have the same lateral width specified for statically tested 
restraints.
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    \13\ Changes to the dynamic test procedures were also proposed, 
including a new sled pulse corridor. Also, the entire vehicle would 
be mounted on the test sled, not merely the seat.
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G. December 2004 Final Rule

    On December 14, 2004, after considering the public comments and 
other available information, NHTSA published in the Federal Register 
(69 FR 74848) a final rule upgrading Federal Motor Vehicle Safety 
Standard No. 202, Head Restraints (FMVSS No. 202). The new upgraded 
version of the standard was designated as FMVSS No. 202a.
1. In General
    To provide better whiplash protection for a wider range of 
occupants, the rule required that front outboard head restraints meet 
more stringent height requirements. Fixed front head restraints must be 
not less than 800 mm. In their lowest adjustment position, adjustable 
head restraints must not be lower than 750 mm, and in their highest 
position, they must be at least 800 mm. To reduce the distance that a 
vehicle occupant's head can be whipped backward in a rear end crash, 
this rule established new requirements limiting backset in front seats 
and limiting the size of gaps and openings in the restraints. The rule 
also established new strength and position retention requirements. 
Finally, it significantly amended the dynamic compliance test option 
currently in the standard to

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encourage continued development and use of ``active'' head restraint 
systems because the test is designed to allow a manufacturer the 
flexibility necessary to offer innovative active head restraint designs 
while still ensuring a minimal level of head restraint performance.
    In developing the final rule, the agency decided not to require 
head restraints for rear seating positions. However, in order to ensure 
that head restraints voluntarily installed in rear outboard seating 
positions do not pose a risk of exacerbating whiplash injuries, the 
final rule required that, if provided, those head restraints meet 
certain height, strength, position retention, and energy absorption 
requirements, but no backset limit. The head restraint regulation of 
the United Nations/Economic Commission for Europe (UN/ECE) also does 
not mandate rear seat head restraints, but manufacturers can 
voluntarily choose to have rear head restraints type approved per the 
regulation.
    The agency explained that in the future stages of its efforts to 
improve occupant protection in rear impacts, it intends to evaluate the 
performance of head restraints and seat backs as a single system to 
protect occupants, just as they work in the real world, instead of 
evaluating their performance separately as individual components. 
Accordingly, in making our decisions about the upgraded requirements 
for head restraints, we sought, e.g., through upgrading our dynamic 
test procedure option, to make those requirements consistent with the 
ultimate goal of adopting a method of comprehensively evaluating the 
seating system.
    NHTSA also sought to harmonize the FMVSS requirements for head 
restraints with the head restraint regulation of the UN/ECE, except to 
the extent needed to provide increased safety for vehicle occupants or 
to facilitate enforcement.\14\ In some instances, a desire to achieve 
increased safety in a cost effective manner made it necessary for us to 
go beyond or take an approach different from that in the ECE 
regulation.
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    \14\ The regulation, adopted by the UN/ECE's Working Party 29, 
World Forum for Harmonization of Vehicle Regulations, is ECE 17, 
Uniform Provisions concerning the Approval of Vehicles with regard 
to the Seats, their Anchorages, and any Head Restraints (http://www.unece.org/trans/main/wp29/wp29regs/r017r4e.pdf).
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    The agency estimated that approximately 272,464 whiplash injuries 
occur annually, and that the final rule would result in approximately 
16,831 fewer whiplash injuries, 15,272 involving front seat occupants 
and 1,559 involving rear seat occupants. The estimated average cost in 
2002 dollars, per vehicle, of meeting the rule was estimated to be 
$4.51 for front seats, and $1.13 for rear seats currently equipped with 
head restraints, for a combined cost of $5.42. The cost per year was 
estimated to be $70.1 million for front head restraints and $14.1 
million for optional rear head restraints, for a combined annual cost 
of $84.2 million. The final rule was considered to be economically 
significant because the agency estimated that it would result in 
economic benefits in excess of $100 million.
2. Details of the December 2004 Final Rule
    Under the final rule, the top of the front outboard integral head 
restraint must reach the height of at least 800 mm above the H-point, 
instead of the 700 mm above the seating reference point (SgRP) \15\ 
previously required. The top of the front outboard adjustable head 
restraint must be adjustable to at least 800 mm above the H-point, and 
cannot be adjusted below 750 mm.
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    \15\ The term ``seating reference point'' is fully defined in 49 
CFR 571.3. It represents a unique design H-point. The H-point is the 
mechanically hinged hip point of an SAE J826 (July 1995) three-
dimensional manikin (SAE J826 manikin), which simulates the actual 
pivot center of the human torso and thigh.
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    If a manufacturer chooses to install head restraints in rear 
outboard seating positions, these head restraints must meet certain 
height, strength, position retention, and energy absorption 
requirements. The rear outboard head restraint is defined as a rear 
seat back, or any independently adjustable seat component attached to 
or adjacent to the rear seat back, that has a height equal to or 
greater than 700 mm, in any position of backset and height adjustment, 
as measured with the J826 manikin. Accordingly, any rear outboard seat 
back or any independently adjustable component attached or adjacent to 
that seat back that exceeds 700 mm above the H-point, must meet the 
above requirements.
    In recognition of the manufacturing and measurement variability 
concerns highlighted by the industry commenters, the agency increased 
the maximum allowable backset for front head restraints from the 
proposed 50 mm to 55 mm. Backset adjustment to less than 55 mm was 
permitted. However, the backset may not be adjustable to greater than 
55 mm when the top of the front head restraint is positioned between 
750 and 800 mm, inclusive, above the H-point. There is no backset limit 
for optional rear head restraints. The agency specified use of a Head 
Restraint Measurement Device (HRMD), consisting of a head form 
developed by the Insurance Corporation of British Columbia (ICBC) 
attached to the Society of Automotive Engineers (SAE) J826 manikin 
(rev. Jul 95), for measuring backset compliance.
    The minimum width requirement for front outboard head restraints in 
vehicles without a front center seating position, and for optional rear 
head restraints is 170 mm. The minimum width requirement for front 
outboard head restraints in vehicles with a center seating position 
between the outboard positions is 254 mm. For integral head restraints, 
there is a limit of 60 mm on the maximum gap between the head restraint 
and the top of the seat. The gap limit for adjustable head restraints 
in their lowest position of adjustment and any position of backset 
adjustment is similarly 60 mm. For all head restraints, gaps within the 
restraint are also limited to not more than 60 mm.
    Under the final rule, an adjustment retention mechanism that locks 
into place is mandatory for all adjustable head restraints. Retention 
of the head restraint in its vertical position is tested using a 
loading cylinder measuring 165 mm in diameter and 152 mm in length. The 
rearward (with respect to the seat direction) position retention 
testing is conducted using a loading sphere, with the seat back braced. 
Under both tests, the head restraint must return to within 13 mm of the 
initial reference point, an increase from the proposed 10 mm return 
requirement.
    The energy absorption test procedure is conducted using a linear 
impactor, rather than the proposed free-motion impactor or the pendulum 
impactor used in ECE 17.
    The dynamic compliance option utilizes a Hybrid III 50th percentile 
adult male test dummy only, as the 95th percentile Hybrid III dummy is 
not yet available for compliance purposes. The head-to-torso rotation 
is limited to 12 degrees, and the maximum HIC15 was limited 
to 500 instead of 150 in the NPRM. These performance limits must be met 
with the head restraint midway between the lowest and the highest 
position of adjustment rather than at the lowest position as proposed.
    Between the effective date of the final rule and September 1, 2008, 
manufacturers were permitted to comply with FMVSS No. 202 by meeting: 
(1) All the requirements of the current FMVSS No. 202, (2) the 
specified requirements of ECE 17, or (3) all the requirements of FMVSS 
No. 202a. NHTSA has found that ECE 17 is functionally equivalent to the 
existing FMVSS No. 202, so it permitted

[[Page 25488]]

compliance with ECE 17 during the interim.

II. Petitions for Reconsideration

    We received seven petitions for reconsideration. Four were from 
auto manufacturers or an auto manufacturer trade association: the 
Alliance of Automobile Manufacturers (Alliance), Ford, DaimlerChrysler, 
and BMW. Two were from seat manufacturers: Johnson Controls and Keiper. 
The seventh petition was submitted by Syson-Hill and Associates, an 
engineering services firm. We note that we also received a petition 
from Kongsberg Automotive. However, since this was not submitted within 
the required timeframe for petitions for reconsideration, our 
regulations provide that it is treated as a petition submitted under 49 
CFR part 552, rather than a petition for reconsideration. We address 
this petition for rulemaking in a separate section at the end of this 
notice.
    In this section, we provide a brief summary of the issues raised by 
the petitions. The summary is representative and does not necessarily 
identify each petitioner which raised a particular issue.

A. Backset Requirement

    Several petitioners asked the agency to reconsider the 55 mm 
backset requirement. The Alliance stated that it believes there are 
potential safety disbenefits from the requirement. It argued that the 
55 mm backset requirement measured at 25 degree torso angle is too 
aggressive and will create significant dissatisfaction. The Alliance 
stated that while it agrees less backset is better, a better balance 
between customer comfort and safety benefits must be achieved. It 
requested a maximum 70 mm requirement with ``a 10 mm audit allowance to 
80 mm.''
    DaimlerChrysler stated that it firmly believes that the backset 
requirement for front seats is overly restrictive and should be 
relaxed. That company stated that its experience suggests that designs 
meeting this requirement will encounter very strong consumer 
resistance. DaimlerChrysler stated that it designed the head restraints 
for a new vehicle to meet the backset requirements included in the 
NPRM, i.e., 50 mm at a torso angle of 25 degrees. It stated that 
consumer reaction from some customers, especially short-statured 
drivers, was very negative, and that some have removed or reversed the 
head restraint.
    Daimler Chrysler asked the agency to reconsider the 25 degree torso 
angle as well as the 55 mm limit. That company stated that there are 
several vehicle concepts, including light trucks, in which an angle of 
25 degrees is much greater than the design and not realistic, thus 
leading to a much larger backset measured in the specified procedure as 
compared to a real world situation. DaimlerChrysler recommended that 
the agency specify the ``design torso angle'' rather than 25 degrees.
    Johnson Controls stated that it believes a 90 mm backset 
requirement would best accomplish the goals of safety and passenger 
comfort while recognizing the practical effects of design and 
measurement variation inherent in the backset measurement technology.

B. Backset Measurement Method

    Ford argued that the backset measurement method and device 
specified in the final rule have not been sufficiently evaluated to 
adequately account for total process variability. It stated that test 
data analysis shows that the actual variability far exceeds the amount 
specified in the final rule, and that the rule is therefore not 
reasonable or practicable.

C. Dynamic Option

    The Alliance stated that it believes the dynamic test alternative 
included in the final rule is premature and not adequately supported 
and developed for use at this time. It requested that the agency 
investigate other alternatives and, in the meantime, retain the 
existing dynamic test in FMVSS No. 202.

D. Rear Seat Non-Use Positions

    Petitioners for reconsideration asked the agency to make several 
changes in the requirements for rear seat non-use positions. The 
Alliance and Ford petitioned the agency to allow head restraint designs 
that manually retract (without having to rotate) to non-use positions 
and that must be manually repositioned to in-use positions. The 
Alliance, BMW and DaimlerChrysler requested that the manually stowed 
non-use position compliance option originally in the NPRM be reinstated 
except that the required torso angle change should be no more than 5 
degrees. GM recommended several options for visual cues to indicate 
that a rear seat head restraint is in a non-use position.

E. Effective Date

    The Alliance stated that while the date set forth in the final rule 
appears to provide more than three years leadtime, it was concerned 
that that leadtime will be subsumed during the period petitions for 
reconsideration are before the agency. It argued that additional 
leadtime could be needed depending on when the agency resolved issues 
raised in the petitions. The Alliance also requested that in order to 
permit manufacturers to implement the required changes with the start 
of a new model cycle rather than at the end of the current model 
design, NHTSA should modify the compliance date to require 80 percent 
compliance with FMVSS No. 202a for the first year and 100 percent 
beginning the second year, with carry-forward credits.

F. Other Issues

    The petitioners for reconsideration raised a number of other 
issues, including ones related to the height requirement, gaps between 
the head restraint and the seat back, the backset and height retention 
(lock) tests, the energy absorption test and seat back bracing, head 
restraint clearance, the width of head restraints for certain seats, 
the option to comply with ECE 17, temperature and humidty, and owner's 
manual requirements.

III. Development of Global Technical Regulation on Head Restraints

    For the past couple years, NHTSA has been leading efforts to 
develop a Global Technical Regulation (GTR) on head restraints. During 
the November 2004 meeting of WP.29 and the Executive Committee of the 
1998 Global Agreement, NHTSA formalized its sponsorship of the 
regulation on Head Restraints as identified in the Program of Work of 
the 1998 Global Agreement. In a notice published in the Federal 
Register (69 FR 60460) on October 8, 2004, NHTSA sought comments on a 
proposal that formalizes the U.S. sponsorship of a GTR on head 
restraints. The agency did not receive any comments.
    The proposal was formally presented by the U.S. and adopted by the 
Executive Committee and referred to the Working Party of Experts (GRSP) 
at the March 2005 Session of WP.29. In February 2005, the GRSP formed 
an informal working group, chaired by the US, to develop a GTR. The 
working group has met eight times with the following contracting 
parties and representatives participating: Netherlands, France, Canada, 
Japan, Germany, Spain, Korea, the UK, USA, the EC, the European 
Association of Automotive Suppliers (CLEPA) and the International 
Organization of Motor Vehicle Manufacturers (OICA).
    In developing and drafting the new GTR, the working group is 
combining elements from UNECE Regulations Nos. 17, 25, and newly 
upgraded FMVSS No. 202, as well as considering proposals for

[[Page 25489]]

requirements not contained in the previously mentioned regulations. The 
working group is exchanging data and has started drafting the 
regulatory text.
    The major outstanding issues are:
     Applicability: Applying the GTR to vehicles up to 4,500 kg 
or limiting it to 3,500 kg.
     Backset: There is general consensus that it should be 
regulated, but the maximum backset limit is still being discussed.
     Measuring procedures for height and backset: There is 
continued discussion on using the H-point or R point as the point of 
reference.
     Dynamic Test: The issue of how to evaluate dynamic systems 
continues to be under discussion.
    The working group has submitted four Progress Reports on the status 
of this GTR. They can be found in Docket No. NHTSA-2004-14395.
    We note that the work on the GTR has been proceeding at the same 
time that NHTSA has been evaluating the petitions for reconsideration. 
Some of the issues that are the subject of the petitions for 
reconsideration have also been raised in the context of the GTR. In 
this document, we are addressing those issues in the context of the 
petitions for reconsideration of the recently upgraded FMVSS No. 202. 
If the development of the GTR continues to proceed successfully and it 
is ultimately adopted, and if the U.S. has voted for its adoption, 
NHTSA would issue an NPRM based on the GTR for a new FMVSS.

IV. March 2006 Partial Response to Petitions

    On March 9, 2006, NHTSA published in the Federal Register (71 FR 
12145) a final rule; partial response to the petitions for 
reconsideration.\16\ In that document, the agency delayed the date on 
which manufacturers must comply with the requirements applicable to 
head restraints voluntarily installed in rear outboard designated 
seating positions from September 1, 2008 until September 1, 2010. The 
agency stated that the remaining issues raised by petitioners for 
reconsideration would be addressed in a separate document.
---------------------------------------------------------------------------

    \16\ Docket No. NHTSA-2006-23848.
---------------------------------------------------------------------------

V. Overview of Decision

    This document addresses the remaining issues raised by petitioners 
for reconsideration of the December 2004 final rule upgrading the 
agency's head restraint standard. We are partially granting and 
partially denying the petitions. The more significant changes that we 
are making in response to the petitions include:
     Leadtime: For the front seat requirements, we have decided 
to provide one additional year of leadtime and also establish a one-
year phase-in with an 80 percent requirement. The agency previously 
extended the compliance date for the rear seat requirements by two 
years. We are also establishing a one-year phase-in with an 80 percent 
requirement for the rear seat requirements.
     Backset: We are making two changes related to the backset 
requirement. First, we are specifying in FMVSS No. 202a that backset is 
determined by taking the arithmetic average of three measurements, 
rather than using a single measurement. Two studies, one by NHTSA and 
one by Transport Canada, have indicated that taking an average of 
several measurements reduces variability. Second, we are slightly 
relaxing the backset requirement by specifying that the 55 mm backset 
limit applies with the seat back at the vehicle manufacturer's 
specified design angle rather than at 25 degrees. This decision 
reflects consideration of interrelated issues and data concerning the 
55 mm backset limit, comfort, and seat back angle.
     Rear Seat Non-Use Positions: To provide greater 
flexibility in this area, we are adding (as included in the NPRM) an 
option for a 10-degree change in the torso reference angle criteria.
     Gaps Between Head Restraint and Seat Back: We are adding a 
manufacturer option under which the gap requirement may be met by 
either the existing FMVSS No. 202a procedure using a sphere or one 
based on the ECE 17 measurement methodology.
     Backset and Height Retention (Lock) Tests: We are 
specifying that instead of returning to the reference loads of 37 Nm 
and 50 N after application of the peak load during these tests, that 
the load be reduce to zero and then increased to the reference loads.
    As discussed in the sections which follow, we are making a number 
of other changes as well.
    Finally, as indicated above, the agency has separately been leading 
efforts to develop a GTR on head restraints. Some issues raised by 
petitioners for reconsideration, including ones related to backset and 
the dynamic test, are also being discussed in the context of the GTR. 
While it is necessary for us to issue today's decision in order to 
respond to the outstanding petitions for reconsideration, we note that 
if agreement is achieved on the GTR, we will consider making changes in 
these and other areas.

VI. Response to Petitions

A. Backset Requirement

1. Petitions
    Several petitioners, including automobile manufacturers and seat 
manufacturers, requested reconsideration of the 55 mm backset 
requirement.
    Under the final rule, backset is measured using an HRMD consisting 
of a head form developed by ICBC attached to the SAE J826 manikin (rev. 
Jul 95). The head form includes a probe that slides rearward until 
contact is made with the head restraint. The resulting measurement 
reflects the horizontal distance between the back of the head of a 
seated 50th percentile adult male occupant and the front of the head 
restraint.
    Under the final rule, backset must not exceed 55 mm for front 
seats, with the seat back positioned at an angle that gives the J826 
manikin a torso reference line angle of 25 degrees. We will refer to 
the torso reference line angle and seat back angle interchangeably.
    In addressing the petitioners' requests concerning the backset 
requirement, we will consider together issues related to the 55 mm 
value, test procedure variability, specification of the HRMD, and seat 
back angle, as they are closely interrelated.
    The Alliance stated that it believes that the 55 mm backset 
requirement measured at 25 degree torso angle is too aggressive and 
will create significant customer dissatisfaction. It stated that while 
it agrees that reducing backset is desirable, a better balance between 
customer comfort and safety benefits should be achieved. That 
organization stated that 5th percentile female stature occupants do not 
sit at 25 degree torso angles, but prefer about 18 degrees and some as 
little as 14 to improve their ability to see the road ahead.
    The Alliance stated that this is corroborated by the 2001 UMTRI 
response to the NPRM, which indicates a mean seat back (torso angle) of 
22 degrees with a 3.2 degree standard deviation. The petitioner argued 
that this more upright back angle greatly reduces the backset to the 
point it interferes with the head of some of these occupants, if not 
just their hair.
    (NHTSA notes that backset is reduced with more upright seat back 
angles because the angle of an occupant's head relative to the 
occupant's torso changes as the occupant's seat back angle is changed. 
As an occupant's seat back

[[Page 25490]]

angle is reduced, making the seat back more vertical, the occupant's 
head is tilted increasingly further back with respect to their torso. 
Conversely, as the back angle is increased, the occupant's head is 
tilted further forward.)
    The Alliance stated that negative consumer reactions to a recent 
new vehicle introduction with a 50 mm backset head restraint at 25 
degree torso angle included removal and reversal of the head restraint. 
That organization indicated that increasing the torso angle a couple 
degrees did not satisfy customers. The Alliance also stated that 
drivers' increasing the seat back angle to relieve the close proximity 
of the head restraint to their heads may result in positioning the seat 
back at an angle greater than the one that provides optimal vision of 
the vehicle controls and displays, headroom, and lumbar comfort.
    The Alliance stated that while the 50 mm backset requirement was 
relaxed to 55 mm in the final rule by NHTSA to account for a 5 mm 
measurement variability range of the HRMD, it does not account for a 2 
degree design tolerance for seat back torso angle or an H-point 
tolerance of 12 mm. The Alliance stated that it believes a maximum of 
70 mm should be adopted with a 10 mm audit allowance, making the limit 
effectively 80 mm. According to the Alliance, this would still make it 
necessary for manufacturers to design front head restraints within the 
IIHS Acceptable or Good rating for geometry.
    DaimlerChrysler stated that it firmly believes the backset 
requirement for front seats is overly restrictive and should be 
relaxed. That company stated that its experience suggests that designs 
meeting this requirement will encounter very strong consumer 
resistance. It made a number of the same arguments as the Alliance, in 
some cases in more detail.
    DaimlerChrysler indicated that it recently introduced a new vehicle 
in the U.S. market that was designed just after the issuance of the 
NPRM for the head restraint rule. That company stated that it 
ambitiously designed the head restraints for this new vehicle to meet 
the backset requirements of the NPRM, i.e., 50 mm at a torso angle of 
25 degrees. DaimlerChrysler stated that the reaction from some 
customers has been very negative, with more than two percent of 
customers rating them unacceptable in a recent survey of owners. That 
company stated that given this response, it embarked on a high priority 
redesign effort to change the backset to 65 mm at a 25 degree torso 
angle.
    According to DaimlerChrysler, it appears that a high percentage of 
5th percentile female drivers object to the head restraints. It stated 
that some of these drivers are removing the head restraint and others 
are reversing the head restraint. DaimlerChrysler also stated that 
merely reclining the seat further has not been an acceptable solution 
for some drivers (especially those of short stature), and could also 
degrade visibility of controls, displays and rearward visibility.
    DaimlerChrysler also stated that studies by the IIHS conclude that 
women are at greater risk of neck injury than men. That company argued 
that a new head restraint standard should protect those at the greatest 
risk, where the benefits are greatest, and where discomfort issues have 
the greatest consequences. DaimlerChrysler argued that referencing the 
backset requirement from a 25 degree torso angle, an angle more 
consistent with the angles typically used by larger stature (i.e., 
taller) occupants than those used by smaller stature occupants biases 
the requirement in favor of the larger stature occupants at the expense 
or discomfort of smaller stature occupants.
    DaimlerChrysler stated that the UMTRI submission in response to the 
NPRM showed mean seat back angles to be 22.5 degrees with a standard 
deviation of 3.5 degrees. According to DaimlerChrysler, the mean angle 
minus 2 standard deviations approximates the 5% female occupant and the 
mean angle plus 2 standard deviations approximates the 95% male 
occupant. It stated that this shows, on average, a 14 degree range in 
seat back angle between these upper and lower size occupants for 
automotive design. DaimlerChrysler stated that with NHTSA's assumed 3 
mm change in backset per degree change in seat back angle, most of the 
55 mm backset is lost for the 5% female without any accommodation for 
hair clearance. DaimlerChrysler suggested that the regulation specify 
the backset at the seat back design angle.
    DaimlerChrysler provided other arguments in support of specifying 
backset at the seat back design angle. It argued that there are several 
vehicle concepts (e.g., light trucks, minivans, SUV's and full size 
vans) in which an angle of 25 degrees is not realistic, thus leading to 
a much larger backset in NHTSA's procedure as compared to the real 
world situation. That company stated that SAE J-1100 July 2002 
recommends a 22 degree nominal torso design angle. It urged the agency 
to use the ``design torso angle.''
    In a later submission, DaimlerChrysler indicated that nominal seat 
back angles for high vehicles, e.g., light trucks, are approximately 20 
degrees, whereas for other vehicles, e.g., sedans they are 
approximately 23 to 25 degrees. It indicated that a 1 degree increase 
of seat back angle yields 3 to 4 mm increase of backset.
    On the issue of the 55 mm backset limit and variability, 
DaimlerChrysler stated that while the final rule made some 
accommodation for measurement variance for the HRMD, the net effect of 
the 55 mm backset limit is less than a 50 mm backset design. It argued 
that the 5 mm increase that NHTSA included in the final rule does not 
account for seat back (torso angle) tolerances that are 2 
degrees, and H-point tolerances of 12 mm. In a later 
submission, DaimlerChrysler argued that a ``worst case'' sum of backset 
tolerances is 29 mm. This includes 5 mm for seat upholstery, 10 mm for 
torso angle of the manikin, 10 mm for head rest rod to seat back angle, 
and 4 mm for seat reference point. DaimlerChrysler indicated that it 
would be necessary to design to a 26 mm backset limit to allow for 
these worst case tolerances.
    DaimlerChrysler stated that all of its arguments point to the need 
for greater backset, and an audit allowance of at least a 10 mm beyond 
the intended nominal requirement. It requested a nominal backset 
requirement of 70 mm, with an additional 10 mm allowance for 
compliance.
    DaimlerChrysler characterized NHTSA's philosophy in the head 
restraint rulemaking as being ``if a little backset is good, less is 
better,'' and argued such an approach cannot be justified below 70 mm 
of backset. That company stated that it agreed that, all things being 
equal, ``the less the backset, the better,'' but a balance between 
``customer acceptance'' and ``a better theoretical design'' should be 
achieved. DaimlerChrysler argued that until the mechanism and threshold 
for whiplash is completely understood, overly ambitious targets should 
be avoided until they can be backed by better fundamental knowledge of 
the causation and prevention of rear impact induced neck injuries and 
customer acceptance.
    Ford stated that it believes the backset measurement method and 
device have not been sufficiently evaluated to account adequately for 
total process variability. It stated that its test data analysis found 
significantly greater operator/gauge variability than that suggested by 
the agency in its rule.
    Ford argued that the capability of the HRMD and related measurement 
process has not been sufficiently established. That company stated that 
the final rule preamble stated that

[[Page 25491]]

``maximum allowable backset requirement is based on the 5 
mm tolerance of the measuring device'' and that the tolerance 
``represents the variability associated with measuring backset with the 
ICBC measuring device.'' Ford argued that this statement does not 
define in acceptable statistical terms the accuracy of the measuring 
device and that sufficient data are not provided to permit an 
assessment of the accuracy of the measuring device.
    Ford argued that, as a threshold matter, the accuracy of the 
measuring device must be determined. It asserted that accuracy 
characterizes the level of deviation of the measurement device output 
from known ``accurate'' values, and that accuracy evaluation is 
performed utilizing calibration procedures using established certified 
specimens that are traceable to nationally recognized standards 
typically maintained by the National Institute of Standards & 
Technology. Ford claimed that without such traceability it is 
impossible to evaluate ICBC's claim that ``that the HRMD yields a level 
of accuracy of 5 mm when used by competent, well-trained 
operators.''
    Ford stated that RONA Kinetics, the developer and manufacturer of 
the HRMD,\17\ calibrates all new HRMDs, but there are no studies to 
indicate how well that calibration is maintained over time in various 
test labs. According to Ford, there is no calibration procedure that 
test labs can use to check calibration retention. It argued that 
because the true accuracy of HRMDs is not known, seat manufacturers and 
agency contractors cannot reliably verify compliance with the backset 
requirement of 55 mm. Ford argued that the agency should develop the 
accuracy requirements for the HRMD, verify that the proposed HRMDs 
satisfy these minimum requirements, and develop calibration standards 
and the necessary equipment to permit periodic calibration of the test 
device at the point of use.
---------------------------------------------------------------------------

    \17\ We note that some commenters refer to the ICBC device as 
HRMD, whereas the agency refers to the combined ICBC device and J826 
manikin as the HRMD.
---------------------------------------------------------------------------

    Ford stated that once accuracy and calibration are established, 
repeatability and reproducibility as well as other major variability 
factors should be assessed with a study. According to that company, a 
comprehensive study should be conducted to assess the statistical 
distribution of the backset measurement on a sufficient sample of seat 
designs representative of the United States light vehicle fleet and 
these measurements should be compared to the actual backset. Ford 
stated that these variables include, but are not limited to, different 
HRMD machines, different J826 manikins, different operators, different 
laboratories, differing temperatures and humidity, as well as the 
variability of the parameters set forth in the agency's compliance test 
procedure.
    Ford stated that in the absence of these data, it undertook a 
preliminary study to assess the accuracy of the HRMD. According to 
Ford, this study did not attempt to evaluate all major sources of 
potential variability. The preliminary study evaluated three different 
seats designed to meet the IIHS good rating, and used three trained 
operators using their own HRMD and associated J826 manikins.
    Ford stated that of five combinations it evaluated, only one 
combination across three paired operators/gauges had a range of 10mm. 
The remaining combination ranges were between 19 mm and 21 mm. Ford 
stated that if it assumed that the 5 mm ``tolerance'' 
represents a range of 10 mm, these results double what the agency 
stated manufacturers should expect when measurements are taken by 
trained HRMD operators.
    Ford also stated that this study excluded certain significant 
potential variables, including the impact of various laboratories, 
temperature and humidity variances, and manufacturing variability. Ford 
argued that its study identifies the need for the agency to perform the 
necessary work to determine the actual capability of the HRMD, and that 
the agency needs to consider and address other potential sources of 
variability and develop a reasonable and practicable backset 
requirement.
    Ford also submitted data which it argued indicated that multiple 
variabilities mean that head restraint designs must use a backset less 
than 30 mm to assure statistical significance.
    Ford later submitted the results of two studies addressing comfort 
and backset. That company stated that the studies show that it is not 
possible to design a seat that is both statistically compliant with the 
55 mm requirement and comfortable for a vast majority of drivers. That 
company argued that the data show that the design target must be less 
than 19 mm to be compliant statistically with the 55 mm requirement. It 
also stated that the minimum backset required to satisfy 85 percent of 
drivers is 69 to 87 mm, depending on the vehicle model. Ford argued 
that for head restraints that do not adjust in the fore/aft direction, 
the FMVSS 202a backset requirement would have to be at least 98 mm in 
order to satisfy about 85 percent of drivers. Ford stated that fore/aft 
adjustable head restraints could be a solution to the comfort problem 
if FMVSS 202a permitted the 55 mm backset requirement at the most 
forward position of the head restraint.
    Johnson Controls stated that it believes a 90 mm backset 
requirement would best accomplish the goals of safety and passenger 
comfort while recognizing the practical effects of design and 
measurement variation inherent in the backset measurement methodology. 
It stated that an UMTRI study concluded that backset below 70 mm would 
not accommodate a substantial number of occupants. Johnson Controls 
also argued that the potential for variation in measurement technique 
and the variation inherent in the design tolerances associated with the 
determination of backset require a substantially lower nominal backset 
than the 55 mm limit in the standard. That petitioner noted that the 
agency added 5 mm in light of variability associated with the measuring 
device, but argued that while this is one facet of variation, sources 
of variation include repeatability, reproducibility, trim, foam and 
structure tolerances that are inherent in the designs used.
2. Agency Response
    In responding to the petitions concerning the backset requirement, 
we begin by noting that the agency addressed issues related to backset 
at considerable length in the final rule preamble. As discussed in that 
document, in selecting the 55 mm limit, we attempted to balance 
comfort, safety and measurement variability concerns.
    While all of these concerns are important, we note that in order to 
address the problem of whiplash, it is necessary to reduce the backset 
of many current head restraints. As discussed in the final rule, the 
available scientific data show that whiplash may be caused by 
relatively small amounts of head and neck movements relative to the 
torso.
    Based on the available scientific data, NHTSA estimated that the 
final rule, once fully implemented, would prevent 15,272 front seat 
whiplash injuries annually. By contrast, we estimate that if the 55 mm 
backset limit were relaxed to 70 mm, the number of prevented injuries 
would be reduced by almost half, to 7,743. In the final rule preamble, 
we noted that no commenter disputed scientific data indicating that the 
closer the head restraint is to the occupant's head at the time of 
impact, the better the protection the head restraint offers.

[[Page 25492]]

    On reconsideration, for reasons discussed below, we have decided to 
make two changes related to the backset requirement. First, we are 
specifying in FMVSS No. 202a that backset is determined by taking the 
arithmetic average of three measurements, rather than using a single 
measurement. Two studies, one by NHTSA and one by Transport Canada, 
have indicated that taking an average of several measurements reduces 
variability. Second, we are slightly relaxing the backset requirement 
by specifying that the 55 mm backset limit applies with the seat back 
at the vehicle manufacturer's specified design angle rather than at 25 
degrees. This decision reflects consideration of interrelated issues 
and data concerning the 55 mm backset limit, comfort, and seat back 
angle.
    In explaining our decision in this area, we will begin with a 
discussion of issues related to suitability of the HRMD. We will then 
address issues related to comfort, seat back angle, and the 55 mm 
backset limit.
a. Suitability of the HRMD and Measurement Variability
    In the final rule preamble, we addressed issues related to 
specifying use of the HRMD for measuring backset and test variability. 
As discussed earlier, the agency relaxed the backset requirement from 
the proposed 50 mm by 5 mm, to 55 mm, to account for the variability 
associated with measuring backset with the HRMD.
    The HRMD consists of a SAE J826 three-dimensional manikin with a 
head form designed by ICBC attached. The SAE J826 manikin is sometimes 
referred to as an ``OSCAR'' device. The ICBC head form includes a probe 
that slides rearward until contact is made with the head restraint, 
thereby measuring backset.
    In commenting on the NPRM, most vehicle manufacturers and seat 
suppliers had opposed the use of the HRMD. Generally, they questioned 
the accuracy and repeatability of head restraint geometry measurements 
made using that device. Further, the HRMD was deemed too sensitive to 
foam, trim, actual H-point, temperature, and humidity variations. 
Several commenters argued that the HRMD was not appropriate for 
compliance testing because repeated testing on the same seat assembly 
yielded different results. For example, Ford noted that the 2000 Ford 
Taurus and 2000 Mercury Sable received different ratings despite the 
fact that they are manufactured on the same platform and have identical 
front seats.
    On the other hand, Transport Canada had reported that a study 
commissioned by several Canadian insurance companies, conducted by RONA 
Kinetics and Associates, Ltd., entitled ``Head Restraint Field Study,'' 
concluded that the HRMD is repeatable and an effective predictor of 
head restraint position. Transport Canada has used the HRMD for years 
and finds it to be a convenient and accurate tool.
    In addressing accuracy concerns, ICBC said that the HRMD yields a 
level of accuracy of 5 mm when used by competent, well-
trained operators. ICBC stated further that manufacturers have 
historically had to accommodate similar tolerance levels with other 
compliance testing based on the H-point machine.
    In addressing Ford's comments on different measurement results for 
virtually identical vehicles, ICBC stated that the two seats, while 
identical in theory, had different upholstery materials (leather and 
cloth) and also had different stitching patterns. As a result, the 
deviation between two seat measurements was 5 mm, which ICBC noted was 
enough to warrant awarding two different vehicle head restraint 
ratings.
    ICBC commented that it developed the HRMD because there were no 
similar tools available to produce accurate and repeatable 
measurements. It claimed the HRMD is more biofidelic than other similar 
or proposed devices, because it has an articulating neck joint that 
approximates the C7-T1 joint (i.e., the location on the spine between 
the most inferior cervical vertebra and the most superior thoracic 
vertebra). This allows the operator to approximate human posture at any 
seat back angle. The ICBC noted that there are 35 HRMD devices now in 
use, arguing this makes it a well-accepted compliance tool, and that 
the device is readily available from ICBC. Further, the HRMD represents 
a small cost for demonstrating compliance.
    In adopting the HRMD for the final rule, the agency stated ICBC 
claimed the device has an accuracy of 5 mm. The agency 
stated that because ICBC has a significant amount of experience in 
using the HRMD, its assertion that the overall level of repeatability 
of its device is within a 5 mm, when used correctly, was 
persuasive.
    The agency also concluded that ICBC adequately explained the 
discrepancy between the measurement results for Ford Taurus and Mercury 
Sable. Different upholstery and stitching patterns can result in 
different measurements. If these differences are significant, the 
difference in both height and backset may be significant.
    We also stated we had found that while measuring head restraint 
geometries with the HRMD for use in a cost study, the backset 
measurements varied by a total of 10 mm when NHTSA's Vehicle Research 
and Test Center (VRTC) repeated the measurement of a single vehicle 
seat three times. This was consistent with the ICBC statements showing 
5 mm accuracy.
    In petitioning for reconsideration, petitioners raised many of the 
same issues concerning the HRMD and variability as had been raised in 
the comments. However, additional data was submitted, including the 
results of the preliminary study conducted by Ford. In addition, many 
of these same issues have been raised in the context of the 
negotiations for a GTR, and new data have been presented in that 
context. While this document considers the issues for purposes of the 
FMVSS No. 202 final rule, we have taken into account the GTR data since 
it is available relevant information.
    After carefully considering the petitions and other available 
information, we continue to believe that the HRMD is a suitable test 
device.
    First, in response to Ford's argument that the HRMD has not been 
shown to be an ``accurate'' measuring device, we disagree. As indicated 
earlier, the HRMD consists of an SAE J826 manikin with a head form 
designed by ICBC attached.
    The SAE J826 manikin has long been incorporated in NHTSA's safety 
standards for purposes of determining H-point location. See S10.4.2.1 
and S10.4.2.2 of FMVSS No. 208 and S7.2.1 of FMVSS No. 214. Moreover, 
the definitions section of 49 CFR Part 571 defines H-point by 
referencing SAE J826.
    As to the head form designed by ICBC, we note that, in conjunction 
with the ongoing development of a head restraint GTR, Transport Canada 
recently conducted a study \18\ to verify whether the HRMD is an 
adequate tool to measure backset. Among other things, the study sought 
to verify specifications and dimensional tolerances of the HRMD 
headform and measuring probes.
---------------------------------------------------------------------------

    \18\ GTR HR-7-5 (http://www.unece.org/trans/main/wp29/wp29wgs/wp29grsp/head07.html).
---------------------------------------------------------------------------

    Transport Canada reported that the head form is manufactured to 
have a mass of 3150  50 grams, and all linear dimensions of 
the head form are within 0.25 mm of the drawing 
specifications for the head form size ``J'' provided in ISO DIS 6220--
Headforms for use in the testing of protective helmets. It also 
reported that both height and backset

[[Page 25493]]

probes are within 2 mm of the RONA Kinetics drawing 
specifications, and that conformity with the drawing specifications is 
accomplished with a specially designed jig.
    Transport Canada noted that the ICBC HRMD is not patented and 
imitations exist. It indicated, however, that the ICBC HRMD bears the 
ICBC/RONA Kinetics nameplate guaranteeing its authenticity and 
construction accuracy. FMVSS 202a specifies use of the ICBC head form.
    The HRMD is a purely mechanical device. Also, unlike a crash test 
dummy, it is not subjected to crash test forces. Given these 
considerations, we believe that calibration should rarely be needed. We 
note, however, that the International Insurance Whiplash Prevention 
Group (IIWPG), of which ICBC is a member, has identified that 
variability between OSCAR units can be an issue when using the ICBC 
HRMD. To address this issue, IIWPG has developed a ``Gloria jig'' to 
calibrate the combination together as one single unit. We note that 
proper use of test equipment is an issue that NHTSA considers in all of 
its compliance testing. We believe that the issue of calibration of 
HRMD's is an issue for the agency to consider in the context of 
possible inclusion in the Laboratory Test Procedures or Compliance Test 
Procedure (CTP) for FMVSS No. 202a.
    As to specifications for temperature and humidity, we do not 
believe these factors would have any significant effect on the HRMD 
since it is purely mechanical measuring tool. The issue of temperature 
and humidity related to seats is addressed later in this document.
    As part of evaluating the petitions for reconsideration, NHTSA 
conducted an additional study of height and backset measurement 
variability. Transport Canada has also conducted such a study, a 
portion of which was discussed earlier. Studies have also been 
conducted by Ford, the European Automobile Manufacturers Association, 
and Japan.
    To accompany this response to petitions, NHTSA has prepared a 
Technical Analysis Relevant to Petitions for Reconsideration of FMVSS 
202a which, among other things, presents the results of the NHTSA 
study, and also provides analysis of the other studies.\19\ A copy of 
this Technical Analysis will be placed in the docket.
---------------------------------------------------------------------------

    \19\ ``Technical Analysis Relevant to Petitions for 
Reconsideration to the December 14, 2004 FMVSS 202a--Head Restraints 
Final Rule.''
---------------------------------------------------------------------------

    The goal of the NHTSA study was to understand the expected 
variation in backset measurement when using multiple laboratories. The 
NHTSA study concluded, among other things, that taking the average of 
three backset measurements at each of three labs reduced the average 
measurement range between labs by about half (from 8.5 mm to 4.5 mm). 
The backset measurement variability across labs fit between the 
estimates made from the Japanese and Ford data. Using an average of 
three measurements in each backset position of adjustment, at a 2 
standard deviation (s.d.) (97.7 percent) level of certainty, the 
expected variability was 5.64 mm; at a 3 s.d. (99.9 percent) level of 
certainty, the expected variability was 8.47 mm.
    The Transport Canada study, which used eight vehicles, sought to 
verify whether the ICBC HRMD is an adequate tool to measure backset. It 
concluded that the HRMD provides repeatable and reproducible results. 
It also found that increasing the number of measurements always reduced 
the backset measurement variability. Using an average of three 
measurements in each backset position of adjustment, at a 2 s.d. (97.7 
percent) level of certainty, the expected variability was 2.6 mm; at a 
3 s.d. (99.9 percent) level of certainty, the expected variability was 
3.9 mm. We reassessed the Canadian data using the same statistical 
techniques used in our own study and found the 2 s.d. and 3 s.d. values 
to be 2.84 mm and 4.26 mm, respectively.\20\ This was slightly higher 
than Transport Canada reported, but still about half the variability 
the agency study found.
---------------------------------------------------------------------------

    \20\ The difference between the Transport Canada analysis and 
the NHTSA analysis is that Transport Canada reported the average of 
the s.d. of operator measurements from the 8 seats measured, while 
NHTSA reported the square root of the pooled variance of operator 
measurements from the 8 seats.
---------------------------------------------------------------------------

    Given that both the NHTSA and Transport Canada studies indicated 
that increasing the number of measurements reduce backset measurement 
variability, we have decided to specify in FMVSS No. 202a that backset 
is determined by taking the arithmetic average of three measurements, 
rather than using a single measurement. This will help address some of 
the concerns about variability cited by petitioners. We also believe 
that these studies, as well as the information discussed in the final 
rule preamble, confirm that the HRMD is an adequate and appropriate 
tool to measure backset, providing repeatable and reproducible results.
b. Comfort, the 55 mm Backset Limit, and Seat Back Angle
    As indicated above, petitioners for reconsideration argued that the 
55 mm backset requirement measured at 25 degree torso angle is too 
aggressive and will create significant customer dissatisfaction. We 
will address together issues related to the 55 mm limit and the 25 
degree torso angle given the interrelationship between them, e.g., 
reducing the torso degree at which backset is measured by one degree, 
from 25 degrees to 24 degrees, while maintaining the same backset 
limit, would result in head restraint designs with approximately 3 to 4 
mm of additional backset.
    Numerous commenters on the NPRM stated that occupants may be 
intolerant of head restraints very close to the back of their head. 
Further, because of differences in the occupant size, posture and seat 
angle preference, the same head restraint can yield different amounts 
of backset clearance and thus comfort for different individuals.
    In addressing the comments in the final rule preamble, we stated 
that since ICBC reported that 49 of 164 vehicles from model year 2001 
met the proposed 50 mm backset limit, it appears that occupant 
discomfort in front seats is not an insurmountable obstacle. We 
concluded that the available information does not substantiate the 
industry concerns associated with discomfort from front seat back 
adjustment to a more upright position.
    UMTRI had commented that a 50 mm backset causes interference with 
the ``preferred'' head position of 13 percent of drivers. Generally, 
these tend to be smaller occupants, who prefer a more upright seat back 
angle. We stated that the ``preferred'' backset position, as 
articulated by UMTRI, may merely refer to a position that the drivers 
are most accustomed to. We noted that the term does not necessarily 
mean that the position is the only acceptable one or even the safest 
one for a given occupant. We also noted that the driving population as 
a whole is accustomed to a backset position that is, while comfortable, 
not optimal to prevent whiplash injuries.
    We stated that we believed that no significant deviation from the 
proposed backset limit of 50 mm was necessary to provide an 
overwhelming majority of front seat occupants with an acceptable 
backset position. We also stated that any potential discomfort can be 
reduced by a slight increase in seat back angle. We stated that we 
believe that most front seat occupants can increase the seat back angle 
slightly without compromising their ability to reach the steering wheel 
comfortably or see the road ahead. We stated that for every additional 
degree of inclination,

[[Page 25494]]

approximately 3 mm of additional backset clearance would be obtained.
    We also noted that our own measurements of 14 vehicles showed that 
the front seat head restraints in the MY 1999 Toyota Camry, Chevy 
C1500, Chevy S10, Saab 9-5, and Chevy Malibu had backsets within 50 mm. 
This supported comments by ICBC and IIHS that many vehicles already 
have a 50 mm backset. We also stated that we believe the seat 
manufacturers can provide a front seating system design, such as a 
different head restraint shape, that would allow for better comfort.
    As to seat back angle, NHTSA explained in the final rule preamble 
that the seat back angle of 25 degrees was chosen because it is on the 
edge of the range of normally selected seat back angles and would most 
likely be selected by larger occupants. ICBC, which developed the HRMD, 
designed it to be used at 25 degrees. The 25-degree angle is also 
consistent with the methods used by IIHS and the Research Council for 
Automobile Repairs (RCAR) for measurement of height and backset.
    We noted that the 25-degree seat back angle in comparison to 
steeper angles represents a more stringent requirement for backset 
measurements because it maximizes the distance between the head and 
head restraint. However, a 25-degree angle is less stringent for 
measuring head restraint height. We stated that if we decided to adopt 
the manufacturer's design seat back angle, typically around 23 
degrees,\21\ we would be requiring taller head restraints. We also 
stated that we were adopting a single measurement angle for both height 
and backset in order to reduce unnecessary complexity in measurements 
and increase accuracy of testing results. Finally, we noted that using 
the same angle for the measurement of backset and height for every 
seat, rather than the manufacturer's design seat back angle, will allow 
comparison of height and backset measurement from seat to seat.
---------------------------------------------------------------------------

    \21\ SAE J1100--Motor Vehicle Dimensions. All 1999-2000 make and 
model data submitted to NHTSA. The data ranged from 18 to 28 
degrees.
---------------------------------------------------------------------------

    As indicated above, in petitioning for reconsideration, 
DaimlerChrysler argued that there are several vehicle concepts (e.g., 
light trucks, minivans, SUV's and full size vans) in which a seat back 
angle of 25 degrees is not realistic, thus leading to a much larger 
backset using NHTSA's procedure as compared to the real world 
situation. That company stated that SAE J-1100 July 2002 recommends a 
22 degree nominal torso design angle. It urged the agency to use the 
``design torso angle.''
    Also, the Alliance stated that 5th percentile female stature 
occupants do not sit at 25 degree torso angles, but prefer about 18 
degrees and some as little as 14. It argued that this more upright back 
angle greatly reduces the backset to the point it interferes with the 
head of some of these occupants, not just the hair.
    i. Seat Back Angle. After considering the petitions for 
reconsideration, we believe a small amount of additional flexibility is 
appropriate. While we believe the available information shows that no 
major change is needed, we are persuaded that additional flexibility is 
needed to account for vehicles with very upright design angles. As 
indicated above, in petitioning for reconsideration, DaimlerChrysler 
argued that there are several vehicle concepts (e.g., light trucks, 
minivans, SUV's and full size vans) in which a seat back angle of 25 
degrees is not realistic.
    Additional flexibility in this area could be provided either by 
adjusting the backset limit or the specified seat back angle. This is 
because the angle at which the seat back is set for backset measurement 
affects the amount of measured backset.
    To the extent the agency reduces the seat back angle that is used 
for backset measurement, the backset limit is easier to meet. In the 
preamble to the final rule, we assumed a 3 mm reduction per degree of 
backset. Based on subsequent information provided by Ford and 
DaimlerChrysler, we believe a range of 3 mm to 4 mm may be more 
accurate. However, the exact value is vehicle-specific and influenced 
by such factors as the shape of the head restraint.
    While we considered either adjusting the backset limit or the 
specified seat back angle, or a combination of the two approaches, we 
decided that the best way to provide appropriate additional flexibility 
is to specify design seat back angle instead of the 25 degree angle. 
This approach maximizes flexibility for vehicles with very upright 
design angles while minimizing the potential lost benefits.
    As discussed in Supplement to the Final Regulatory Impact Analysis, 
the impact on benefits of changing the backset limit to 60 mm or 
changing seat back angle to design angle is similar (about a 20 percent 
loss in benefits). However, for vehicles with seat back angles 
significantly steeper than 25 degrees, e.g., 20 degrees, specifying 
seat back angle provides significantly greater flexibility.
    As a practical matter, this approach provides some additional 
backset flexibility for most seats, since NHTSA estimates that the 
sales weighted average front seat design seat back angle is 23.5 
degrees.\22\ Specifying that such a seat be tested at the design seat 
back angle instead of 25 degrees is roughly equivalent to increasing 
the backset limit by 4.5 to 6 mm. Therefore, this will also help 
address possible concerns related to comfort.
---------------------------------------------------------------------------

    \22\ ``Technical Analysis Relevant to Petitions for 
Reconsideration to the December 14, 2004 FMVSS 202a--Head Restraints 
Final Rule.''
---------------------------------------------------------------------------

    We note, in considering specifying design angle instead of 25 
degrees, that our analysis of UMTRI data does not show a good 
correlation between design seat back angle and selected angle. However, 
the UMTRI data was limited to 17 vehicles with design angles ranging 
from 22 to 26 degrees, with a majority of vehicles having design angles 
of 24 and 25 degrees. Because the data represent such a limited number 
of different design angles, it has limited value in assessing the 
correlation between average selected seat back angle and design angle 
for a spectrum of design angles. We have not seen data to contradict 
our belief that a reasonable way of identifying the seats that are most 
likely to be used at very steep angles is to rely on the manufacturer 
design seat back angle.
    We also note that while the HRMD was designed to be used at 25 
degrees, the device has an articulation to allow for adjustment of the 
head for varying torso angles. The device can therefore be used at 
different seat back angles. It is relatively rare that a seat can be 
adjusted to have a seat back angle of exactly 25 degrees. Thus, even 
prior to the change to specify seat back angle, the standard specified 
testing in the adjustment position closest to 25 degrees. For these 
reasons, we believe there is no problem in testing vehicles at the 
design seat back angle. We also note that specifying testing at design 
seat back angle will slightly affect the height requirement.
    ii. 55 mm Backset Limit and Comfort. As we respond to issues 
concerning the backset limit and comfort, we will take account of the 
additional flexibility provided by specifying design seat back angle. 
As indicated above, the sales weighted average design seat back angle 
is 23.5 degrees. Specifying that such a seat be tested at the design 
seat back angle instead of 25 degrees is approximately equivalent to 
increasing the backset limit by 6 mm.
    In petitioning for reconsideration, DaimlerChrysler cited consumer 
complaints about the head restraints of a vehicle it said were designed 
to meet the 50 mm backset requirement proposed in the NPRM. The 
petition submitted by the Alliance also cited this

[[Page 25495]]

experience. We note that DaimlerChrysler had also cited this experience 
in commenting on the NPRM, but provided additional information in the 
context of its petition for reconsideration. We also note that some of 
the information submitted by DaimlerChrysler about this issue is 
subject to a claim of confidentiality.
    In discussions with DaimlerChrysler, we were advised that the 
design backset target for the vehicle in question was 47 mm. This was 
intended to provide a margin of compliance, although not one sufficient 
for purposes of certification. In light of DaimlerChrysler's petition, 
NHTSA measured the backset on two versions of this vehicle. Since the 
measurements on one of these vehicles was made with the seat backs a 
few degrees steeper than the 25 degrees specified in the standard, the 
measurements were normalized by adding 4 mm \23\ to the backset for 
each degree less than 25 degrees. The average backset was 28 mm in the 
lowest position of adjustment and 18 mm in the highest position of 
adjustment.
---------------------------------------------------------------------------

    \23\ For every degree the seat back was more upright than 25 
degrees, the measured backset was increased by 4 mm to approximate 
the backset measurement with the seat back set to 25 degrees.
---------------------------------------------------------------------------

    We subsequently learned from DaimlerChrysler that the 47 mm target 
was based on SgRP instead of H-point. However, under the final rule, 
backset measurement is based on H-point. This change is significant. As 
discussed in the final rule preamble, the SgRP is a theoretical design 
point in the vehicle, usually representing the most rearward normal 
riding or driving H-point. It does not necessarily represent the actual 
vehicle build, e.g., it may be 15 or 20 mm forward, rearward, above or 
below the actual vehicle H-point. The HRMD defines the H-point of the 
specific seat being measured and thus is representative of the actual 
backset experienced by an occupant of that seat. Since 
DaimlerChrysler's 47 mm target was based on SgRP instead of H-point, it 
is not surprising that the backset measured according to the final rule 
is very different.
    Given that the as-built backset, measured using the HRMD in 
accordance with the final rule, is on the order of half of the value 
cited in the petition, we believe the complaints about this vehicle are 
not germane to the 55 mm requirement included in the final rule.
    As part of evaluating the petitions for reconsideration concerning 
the backset, we looked at more recent data from IIHS concerning the 
backset of model year 2004 vehicles. That organization measured the 
backset of vehicles representing approximately 100 make/models, or 
about half of the vehicle fleet, using the same procedure as that of 
the final rule. Some make/models were measured multiple times using 
different available seat trim levels. Nearly half of the vehicles (47.1 
percent) had a backset of 55 mm or less. Moreover, more than 30 percent 
had a backset of 45 mm or less, and 25 percent had a backset of 40 mm 
or less.
    We also reviewed our Office of Defect Investigation database for 
consumer complaints about head restraints. The search was restricted to 
2000 and later model year vehicles. Two hundred and five complaints 
were found. These were categorized as various types of complaints. The 
vast majority of the complaints (59%) pertained to the lack of head 
restraint in the rear seating positions of vehicles. Most of these were 
for pickups with two seat rows. Only two complaints (1%) specifically 
mention a lack of sufficient backset. The vehicles with these 
complaints were a 2003 Toyota Camry and a 2004 Honda Pilot.
    Extrapolating the IIHS data to the entire vehicle fleet, we find 
that nearly half of current head restraints have a backset of 55 mm or 
less (tested at a seat back angle of 25 degrees). Yet there is an 
absence of any significant number of consumer complaints. Therefore, we 
do not accept Ford's study claiming that the minimum backset required 
to satisfy 85 percent of drivers is 69 to 89 mm (with an even higher 
value needed for a regulatory requirement due to issues related to 
variability). Ford did not submit many details of how its comfort study 
was performed. However, it is evident that the study was not a blind 
study in that the participants were aware of what was being evaluated. 
This could have had a strong influence on the results as well as the 
wording of the questions asked of each participant. In any event, no 
evidence has been presented that a substantial number of drivers are 
dissatisfied with the backset of the head restraints in half of all 
vehicles.
    We have also considered petitioners' arguments related to the 
``design target'' needed to ensure compliance with a 55 mm backset 
limit. We recognize that manufacturers routinely design their vehicles 
with a compliance margin to meet regulatory requirements. Such margins 
are intended to address both measurement variability (the factor which 
led NHTSA to increase the backset limit by 5 mm in the final rule as 
compared to the NPRM) and build variability. However, we do not accept 
DaimlerChrysler's claim that companies must design to 26 mm in order to 
ensure compliance with a 55 mm limit, or Ford's claims that companies 
must design to 19 mm.
    DaimlerChrysler estimated the design tolerance by providing 
theoretical ranges for various aspects of the seat design and 
estimating their effect on overall backset. These estimates were then 
summed to provide an overall estimate. One problem with this estimate 
is that it is based on theoretical design tolerances as opposed to 
measurements of actual seats. Thus, there is no way to know what 
confidence level of variance they represent.
    Another problem with this estimate is the adding or stacking of 
these tolerances. Stacking of tolerances tends to provide an 
overestimate of the overall tolerance rather than a statistically valid 
estimate. A more appropriate technique would be to use a pooled 
variance technique such as the agency used in its estimates of backset 
measurement variability.\24\ Finally, DaimlerChrysler provided no 
information or arguments about the extent to which it is possible for 
manufacturers to improve these tolerances.\25\
---------------------------------------------------------------------------

    \24\ ``Technical Analysis Relevant to Petitions for 
Reconsideration to the December 14, 2004 FMVSS 202a--Head Restraints 
Final Rule.''
    \25\ DaimlerChrysler did submit confidential information to 
indicate the cost associated with reducing the seat design 
tolerance. However, there was insufficient information provided to 
evaluate the cost estimates.
---------------------------------------------------------------------------

    We also believe there are several problems with Ford's estimate of 
a target backset value. Ford estimated the mean shift to be in the 
range of -3.2 mm to -27.9 mm and from these estimates stated that with 
additional process controls a shift of  15 mm was possible. 
However, the mean shift estimates how close the as-built seat is to 
design. It is not an estimate of random build variance.
    We believe that one of the causes for this difference is the 
reliance of designing seats around the theoretical SgRP, which can 
deviate substantially from the actual H-point. We saw this in the 
results of the backset measured for the DaimlerChrysler vehicle which 
had a design backset of 47 mm based on the SgRP location, but when 
measured as built had a backset of about half of that value. However, 
manufacturers can deal with this issue by designing their vehicles and 
seats in light of the actual H-point for purposes of FMVSS No. 202a. 
Thus, we do not accept a mean shift estimate of 15 mm as 
being necessary for purposes of meeting the backset requirement. 
Supporting this conclusion is data submitted by Ford

[[Page 25496]]

reporting capability of achieving a shift of as little as 3.2 mm.
    In addition to the estimate of mean shift in backset, Ford provided 
estimates of variability around the mean for three vehicles. It also 
submitted data it described as seat-to-seat variability for a Lincoln 
Town Car.
    The s.d. for build variability ranged from 5.4 mm to 7.2 mm. Using 
a pooled variance method, the Ford data gives an s.d. of 6.6 mm. 
However, the Ford data also included measurement variability.
    Using data submitted by Japan, NHTSA has made an estimate of seat 
build variability separate from measurement variability. (This analysis 
is included in the Technical Analysis \26\ noted earlier.) The 
technique used in the agency's analysis separates the effects of the 
variability associated with the technician, technician repeated 
measures, the seat build, and any interaction between these covariates. 
The s.d. for build variability of the three seats ranged from 2.7 mm to 
7.3 mm, with a combined s.d. of 3.75 mm.
---------------------------------------------------------------------------

    \26\ ``Technical Analysis Relevant to Petitions for 
Reconsideration to the December 14, 2004 FMVSS 202a--Head Restraints 
Final Rule.''
---------------------------------------------------------------------------

    The s.d. of lab-to-lab measurement variability in NHTSA's study was 
estimated to be 2.82 mm. Transport Canada's study and NHTSA's analysis 
of data submitted by Japan show much smaller measurement variability.
    We can estimate the combined build and measurement variability by 
summing the squares of the s.d. values and taking the square root. 
Thus, the combined s.d. is about 4.7 mm = [(2.82)\2\ + 
(3.75)\2\]0.5. The 2 s.d. estimate of the combined 
measurement and build variability is 9.4 mm. Subtracting this value 
from the 55 mm backset limit, we arrive at a value of 45.6 mm. This is 
far larger than the estimates of 26 mm and 19 mm suggested by 
DaimlerChrysler and Ford as ``design targets.''
    We note that NHTSA does not make estimates of the ``design 
targets'' that manufacturers may need to adopt in order to ensure that 
all of their vehicles comply with a particular requirement. It is up to 
each manufacturer to determine what is necessary to certify using due 
care that each of its vehicles comply with all applicable safety 
standards.
    The above analysis is provided to help show why we do not believe 
the estimates provided by DaimlerChrysler and Ford are necessarily 
representative of what is achievable. Apart from accounting for 
measurement variability, the design target a manufacturer may need to 
adopt in order to ensure that all of its vehicles will comply with a 
particular requirement is primarily dependent on the manufacturer's 
choices concerning design and manufacturing tolerances, and its quality 
control measures.
    We also note, in the context of addressing variability, that some 
manufacturers have argued that the agency should adjust the backset 
limit in light of an additional type of variability, that is associated 
with using the same seat structure for multiple designs related to 
options or trim levels. An example of this is the differences in 
measured backset for the 2000 Ford Taurus and 2000 Mercury Sable, noted 
earlier. We believe this is an issue that manufacturers can address in 
the design process of each seating option or trim level, i.e., ensuring 
that each such design will enable the vehicle to meet the backset 
limit.
    As indicated above, the agency stated in the preamble to the final 
rule that one method a driver could use to achieve additional head 
restraint clearance would be to increase seat back angle slightly. 
Although DaimlerChrysler and the Alliance stated in their petitions 
that this solution had been unacceptable for some, no supporting 
information was provided. Moreover, as indicated above, that experience 
was in the context of a seat with a backset far under the specified 
amount of the final rule. Based on seat geometry, movement of a seat 
back one recliner click would have a minimal effect on the vertical eye 
location of a driver, and a particularly small effect for a seat in a 
more upright position.
    On the issue of whether the backset limit should be increased 
because women are at greater risk of neck injury than men, we note that 
the data indicate that reduced backset reduces the risk of neck injury. 
This suggests that reduced backset is even more important for women 
than men.
    We recognize the importance of acceptable comfort for all 
occupants, including those of short stature. However, we believe that 
the available data do not support the view that the 55 mm requirement 
will create any significant problems for a well designed and well built 
seat. As indicated above, nearly half of the current vehicles measured 
by IIHS had a backset of 55 mm or less, more than 30 percent had a 
backset of 45 mm or less, and 25 percent had a backset of 40 mm or 
less. Moreover, these calculations were made using a seat back angle of 
25 degrees, and the change to design seat back angle will provide 
additional flexibility to typical vehicles. Thus, a large number of 
vehicles in the current fleet show that the new requirement can be met 
without causing significant comfort issues. Finally, as discussed 
further in the Supplemental Final Regulatory Evaluation (SFRE), 
increasing the backset limit along the lines suggested by the 
petitioners would substantially reduce the benefits of the final rule.
    For these reasons, as well as the ones discussed in the final rule 
preamble, we decline to increase the 55 mm backset limit.
    iii. 55 mm Backset Limit, H point and SgRP. In December 2006, the 
Alliance recommended for FMVSS No. 202a \27\ that the backset limit be 
kept ``at no less than 55 mm at the design torso angle using a 
measurement procedure about the ``R'' point (SgRP) derived from ECE R17 
in place of a backset requirement of 80 mm at the design torso angle 
using the ``H'' point (HRMD) measurement method.'' This recommended 
alternative would thus replace the one it presented in its petition for 
reconsideration. The Alliance stated that this would preserve the 
benefits the agency estimated in the FRIA.
---------------------------------------------------------------------------

    \27\ The Alliance also made this recommendation for the GTR that 
is under development.
---------------------------------------------------------------------------

    We note that while the Alliance's recommendation is an alternative 
method of addressing concerns it raised in its petition for 
reconsideration about the backset limit, it represents a very different 
approach. In order to ensure that the agency can fully consider 
particular requests, petitioners for reconsideration should be specific 
in their petition about the relief they desire. We also note that while 
petitioners for reconsideration did not request that the agency use 
SgRP for measuring backset, the issue was raised in connection with 
measuring head restraint height.
    As to the issue of using H-point or SgRP, the agency addressed this 
subject in the preambles to the NPRM and final rule. Use of H-point 
measures the actual vehicle as manufactured and hence the actual 
protection provided to vehicle occupants. By contrast, the SgRP is a 
theoretical design point in the vehicle and does not necessarily 
represent the actual vehicle build. Therefore, we continue to believe 
that use of H-point is a better approach and decline to change to SgRP.

B. Rear Seat Non-Use Positions

1. Petitions
    In the head restraint final rule, NHTSA permitted rear head 
restraints to have non-use positions in limited circumstances. The 
agency decided to permit such positions to address concerns about rear 
visibility. However, the agency also wanted to reduce the

[[Page 25497]]

risk of injuries stemming from misused head restraints.
    In light of these considerations, the agency adopted the following 
requirement: (1) A head restraint in a non-use position must 
automatically return to a normal ``use position'' when the seat is 
occupied by a 5th percentile female dummy whose midsagittal plane is 
aligned within 15 mm of the head restraint centerline; or (2) the head 
restraint must be capable of manually rotating at least 60 degrees 
forward or rearward in a vehicle vertical longitudinal plane between 
the ``use position'' and the non-use position. In explaining its 
decision to allow the latter of these two options, the agency stated 
that if the head restraint is capable of rotating forward or rearward 
by at least 60 degrees to achieve a non-use position, it would clearly 
be in a non-use position, thereby informing the occupant that the head 
restraint is available, but out of place.
    The agency did not adopt a proposed provision that would have 
required that the non-use positions cause a 10-degree change of the 
torso angle of the J826 manikin. This proposed requirement was based on 
the premise that the non-use position should give the occupant an 
obvious physical cue when the head restraint is not properly 
positioned. Given its decisions not to mandate rear head restraints and 
to allow head restraints to be removable without the use of tools, the 
agency concluded that it would be incongruous to mandate a possibly 
complex seat mechanism to ensure that non-use positions provide a 
physical cue to the occupant in the form of a 10-degree change to the 
torso reference angle.
    Petitioners for reconsideration asked the agency to make several 
changes in the requirements for rear seat non-use positions. The 
Alliance and Ford petitioned the agency to allow head restraint designs 
that manually retract (without having to rotate) to non-use positions 
and that must be manually repositioned to in-use positions.
    The Alliance stated that since publication of the NPRM, many new 
vehicles have been designed such that the rear seats retract into the 
floor. The head restraints on these seats can be lowered to a position 
nearly flush with the top of the seat back, allowing the seat to be 
stowed without head restraint removal. It argued that the folding head 
restraints permitted by the final rule would take up too much space 
below the floor. It also argued that removable head restraints allowed 
by the final rule are not preferred by customers and are less likely to 
be available when needed. Ford stated that strong customer demand for 
vehicle functionality requires rear seats with folding or otherwise 
stowable seats.
    The Alliance argued that disallowing retractable head restraints 
may overly restrict otherwise acceptable head restraints and is 
contrary to the interests of occupant safety. Ford stated that the 
restriction is not reasonable, necessary or practicable. The Alliance 
requested that the agency allow non-use positions of less than 700 mm, 
and in-use adjustment positions between 700 mm and 750 mm.
    GM recommended several options for visual cues to indicate that a 
rear seat head restraint is in a non-use position. These included a 
permanent label similar to that already present in some Volvo models, 
and indicators that deploy only when the head restraint is in the 
lowest position.
    The Alliance, BMW and DaimlerChrysler requested that the manually 
stowed non-use position compliance option originally in the NPRM be 
reinstated except that the required torso angle change should be no 
more than 5 degrees. DaimlerChrysler stated that the agency's efforts 
to minimize adjustability misuse may have the unintended consequence of 
threatening the very installation of rear seat head restraints. It 
argued that a 5 degree torso angle change would be clearly 
uncomfortable for an adult and would satisfy the agency's concern about 
misuse.
    BMW stated that it believed that NHTSA did not intend to 
inadvertently prohibit designs that meet the agency's proposed 10-
degree change in the torso reference angle criteria, and it believes 
this added option can provide occupants with an obvious physical cue 
that the head restraint is not properly positioned. That company stated 
that, based on the NPRM, it had designed seats to meet the 10-degree 
change in torso reference angle option. However, BMW recommended that 
the agency adopt a 5-degree change in torso reference angle option.
2. Agency Response
    After considering the petitions, we have decided to add an option 
for a 10-degree change in the torso reference angle criteria. Head 
restraints that meet this option will give the occupant an obvious 
physical cue when the head restraint is not properly positioned. We are 
not adopting a 5-degree change in the torso reference angle criteria 
since, for reasons discussed below, we believe this option would not 
provide an obvious physical cue. We are also not adopting the other 
changes requested by petitioners for reasons discussed below.
    In the December 2004 final rule, the agency did not adopt the 
proposed 10-degree torso angle change option for rear seat non-use 
positions in light of concerns raised by commenters that it was overly 
burdensome. We adopted instead the option for head restraints that fold 
forward or rearward by 60 degrees. We concluded that although such 
designs would not necessarily provide a physical cue, they would 
provide a clear visual cue that the head restraint is not in a proper 
use position.
    However, based on our review of the petitions for reconsideration, 
we believe that it would be useful to include the 10-degree torso angle 
change option as well. As indicated above, BMW stated that it has 
designed head restraints to meet this option.
    Given the requests of petitioners, we carefully considered whether 
a 5-degree torso angle change option would provide an appropriate 
physical cue. To explore this question, the agency developed a human 
factors study to determine if an occupant would be likely to reposition 
their head restraint as a function of the torso angle change the head 
restraint produced in the non-use position.\28\
---------------------------------------------------------------------------

    \28\ DOT HS 809 957, ``Rear Seat Stowable Head Restraint Non-Use 
Position Torso Angle Study,'' November 2005.
---------------------------------------------------------------------------

    The baseline seat for this study was the second row captain's chair 
of a 2005 MY Dodge Grand Caravan. In its OEM configuration, the seat 
created a nominal 5 degree torso angle change between its non-use and 
in-use positions. The head restraint was then modified by introducing 
two forward offsets that generated either a 10 or 15 degree torso angle 
change. One other condition that was used was a label attached to the 
head restraint in the 5-degree condition. The label was modified from a 
label used by Volvo.
    Of the participants who adjusted the head restraint, 88% adjusted 
it immediately after sitting down. The 5-degree condition and label 
condition were unsuccessful in motivating participants to adjust the 
head restraint. For the 5-degree condition, only 3 out of 20 
participants (15 percent) adjusted the head restraint. None of the 
participants (0 out of 20) adjusted the head restraint as a result of 
the label. The 10-degree condition had a nearly 80% success rate, 19 
out of 24. Only four participants were run in the 15-degree condition 
since the percentage of participants who adjusted the head restraint in 
the 10-degree condition was high. The 15-degree condition had a 100% 
rate of adjustment.

[[Page 25498]]

    In light of the results of this human factors study, which 
demonstrated the effectiveness of a 10 degree torso angle change and 
the ineffectiveness of a 5 degree torso angle change, we decline to 
adopt petitioners' request for a 5-degree torso angle change option.
    We also decline to adopt the other changes recommended in this area 
by petitioners. As to the issue of permitting manually retractable head 
restraints, we continue to believe that head restraints should not have 
non-use positions unless either there is an automatic return to a 
normal use position feature or there is a clear physical or visual 
signal to occupants that the head restraint is not in a position 
intended for use. This is necessary to help prevent unintentional 
misuse. A head restraint that simply retracts to a lower position 
intended to be a non-use position looks the same to an occupant as a 
head restraint that has a position of adjustment below the required 750 
mm height. There would be no physical or visual cue leading the user to 
adjust the head restraint to the in use position.
    While we appreciate concerns that current designs for rear seats 
that retract into the floor may not come within one of the available 
options, petitioners have not shown that these options could not be met 
by other designs, including ones with more novel packaging. We note 
that the agency extended the compliance date for the rear seat 
requirements to September 1, 2010. This provides additional leadtime 
for design changes. As discussed elsewhere in this document, we are 
also providing a one-year 80 percent phase-in for the rear seat 
requirements.
    As to the Alliance's request that the agency allow in-use 
adjustment positions between 700 mm and 750 mm, we note that the final 
rule specified that the lowest in-use position must be at least 750 mm. 
The rationale for this minimum height requirement was provided in the 
NPRM and final rule. Of particular note, the 750 mm requirement ensures 
that the head restraint will provide benefits to a higher percentage of 
rear seat occupants.
    No new information was provided to support a change in this 
requirement. Issues related to visibility and folding seat storage are 
addressed by allowing for removal and non-use positions. The gap 
requirements assure that short-statured occupants will have head 
restraint protection even when the head restraint is at the 750 mm 
position. We therefore decline to make this requested change.
    As to the request for other options for visual cues to indicate 
that a rear seat head restraint is in a non-use position, including 
labels, no information has been provided to show that such cues would 
be effective. As noted above, in our human factors study, none of the 
participants (0 out of 20) adjusted their head restraints as a result 
of a label. Accordingly, we are not adopting such additional options.
    Finally, we note that in December 2006, the Alliance asked the 
agency to include all of the non-use alternatives within the current 
GTR draft text, including a 450 mm x 55 mm HLE x S 
``Discomfort metric.'' The request concerning ``discomfort metric'' was 
not included in the Alliance's petition. It is, however, relevant to 
the concerns the Alliance raised about rear non-use positions and has 
similarities to the change in torso reference angle approach. The 
specific values for the ``discomfort metric'' are still under 
discussion in the context of developing the draft GTR. Before adopting 
such an approach, we would want to more carefully analyze it. 
Accordingly, we are not adopting a ``discomfort metric'' at this time.

C. Dynamic Option

    The agency included an upgraded optional dynamic test requirement 
in the head restraint final rule which, if chosen, allows a 
manufacturer to forgo certification to the majority of static test 
requirements (S4.3 and S5.3). While the dynamic option is intended to 
facilitate the continued development and use of ``active'' head 
restraint systems, it is available for any head restraint system.
    Under the dynamic option, the entire vehicle is exposed to a half-
sine deceleration pulse with a target of 8.8 g peak and 88 ms duration. 
The 50th percentile male Hybrid III dummy in each seat must have a 
maximum head-to-torso rotation of less than 12 degrees and a HIC15 of 
less than 500.
    While the head restraint standard previously included an optional 
dynamic test alternative, the agency adopted the upgraded alternative 
for several reasons. First, the agency wanted the dynamic test 
alternative to be consistent with the standard's upgraded static test 
requirements, including the height requirement. The existing 
performance limit (45 degree head rotation) was such that very short 
head restraints could comply with the regulation.
    Also, the previous dynamic alternative specified use of a 95th 
percentile adult male dummy. However, the agency had not adopted a 
specific 95th percentile adult male dummy for regulatory purposes. The 
agency specified use of the 50th percentile adult Hybrid III dummy to 
improve objectivity and enforceability.
1. Basic Test Requirement
    In petitioning for reconsideration, the Alliance and 
DaimlerChrysler argued that the test was premature and not adequately 
supported. They stated that the 12 degree rotation limit has no 
biomechanical derivation. They questioned the basis for the injury risk 
curve provided in the preamble of the final rule, which shows whiplash 
risk associated with head translation rather than rotation. The 
Alliance and DaimlerChrysler asked the agency to retain the previous 
dynamic option that specifies a 95th percentile test dummy and a 45 
degree head-to-torso rotation.
    DaimlerChrysler argued that the agency had not provided any 
biomechanical data correlating risk of neck injury with head rotation. 
It claimed that head rotation has been found to be not a good estimator 
for neck injury. It also argued that the agency did not present a cost-
benefit analysis to relate the benefit of reducing head rotation to 12 
degrees. That company argued that there has been no quantifiable 
justification for changing the existing dynamic alternative.
    DaimlerChrysler also stated that studies conducted by IIHS for its 
dynamic head restraint test has eliminated head rotation from 
consideration as an assessment parameter for whiplash injury. It stated 
that IIHS has elected to instead use neck tension and neck shear.
    Ford argued that the head-to-torso rotation may not be functionally 
equivalent to the static requirements, and may be design/technology 
restrictive. It argued that the Volvo WHIPS seat has good field 
performance yet does not pass the 12 degree requirement. That company 
asked that the head-to-torso rotation limit be increased to 20 degrees. 
It argued that this would represent a 10 percent risk of whiplash 
injury. As an alternative, Ford suggested that the agency use neck 
moment as the injury criterion.
    After considering the petitions for reconsideration, NHTSA has 
decided to retain the basic dynamic test alternative included in the 
final rule. We note that the agency previously addressed the general 
criticisms of this option in both the NPRM and final rule preambles. In 
the preamble of the December 14, 2004 final rule and in an associated 
technical report,\29\ the agency showed the

[[Page 25499]]

biomechanical basis for the development of the head-to-torso rotation 
limit.
---------------------------------------------------------------------------

    \29\ Docket No. 2004-19807-05, NHTSA Technical Report, ``Injury 
Criteria and Anthropomorphic Test Devices for Whiplash Injury 
Assessment. NHTSA has also published this study in the 2005 ESV 
conference. Kuppa, S., Saunders, J., Stammen, J., Mallory, A., 
``Kinematically Based Whiplash Injury Criterion,'' 19th ESV 
Conference, Paper No. 0211, 2005. (http://www-nrd.nhtsa.dot.gov/pdf/nrd-01/esv/esv19/05-0211-O.pdf.)
---------------------------------------------------------------------------

    Unfortunately, the agency incorrectly presented in the final rule 
preamble a graph of head displacement rather than head rotation (69 FR 
at 74874). The graph should have been the following:
[GRAPHIC] [TIFF OMITTED] TR04MY07.158

This correct graph addresses some of the questions raised by the 
petitioners.
    DaimlerChrysler cited a technical paper \30\ for its claim that 
head rotation has been found to be not a good estimator for neck 
injury. Using statistical and optimization techniques on published 
biomechanical data, the authors of the paper concluded that neck 
tensile force alone was the best predictor of AIS 3+ neck injury. All 
the biomechanical data used for analysis were those where the subject 
was either uninjured (AIS=0) or the subject sustained AIS 3+ neck 
injuries. Thus, the resulting injury criterion, neck tension or Nij, 
are meant for developing AIS 3+ neck injury criterion. There is no way 
of assessing the risk of AIS=1 neck injuries with these data, which is 
the AIS level for whiplash injuries. Therefore, we do not accept that 
company's argument concerning this paper.
---------------------------------------------------------------------------

    \30\ DaimlerChrysler cited: Nusholtz, G.S., Di Domenico, L., 
Shi, Y., Eagle, P., ``Studies of Neck Injury Criteria Based on 
Existing Biomechanical Test Data,'' Accident Analysis and 
Prevention, May 2002. We note that the correct citation for this 
paper is to Accident Analysis and Prevention, Vol. 35, pp. 777-786, 
2003.
---------------------------------------------------------------------------

    As to Ford's request concerning neck moment, we note that lower 
neck moment was one of the criteria considered by the agency when 
developing the dynamic option proposal. However, we decided in favor of 
head-to-torso rotation for the following reasons.

    We have decided in favor of head-to-torso rotation because, in 
the absence of generally accepted injury criteria specifically 
applicable to whiplash injuries, we believe that a head restraint's 
ability to prevent whiplash is primarily due to its ability to 
prevent the rearward translation and rotation of the occupant's head 
with respect to the torso. The sled tests showed that rearward head 
rotation seemed to correlate with head restraint position. Other 
biomechanics researchers have found a similar correlation and used 
head-to-torso rotations for the evaluation of whiplash injury. The 
agency is willing to reconsider the dynamic performance criteria if 
and when more advanced whiplash injury criteria become available. 69 
FR 74875 (footnote omitted).

    In adopting the upgraded dynamic test, it was our goal to provide a 
level of safety similar to that of the static requirements. However, 
given the differences in the basic nature of the test requirements, we 
do not believe it is possible to provide one-to-one correspondence 
between the two sets of tests. Thus, a particular vehicle may be able 
to pass one test but not the other.
    For reasons discussed above and in the NPRM and final rule 
preambles, we do not believe it would be appropriate to simply retain 
the existing dynamic alternative test requirement. Among other things, 
that requirement is not consistent with the upgraded static test 
requirements with respect to the need for higher and closer head 
restraints. Also, we believe there was a need to specify a specific 
test dummy to improve objectivity and enforceability.
    As to DaimlerChrysler's argument that the agency has not presented 
cost-benefit analysis related to reducing head rotation to 12 degrees, 
the agency addressed, in connection with the December 2004 final rule, 
the costs and benefits of upgraded head restraints. This analysis was 
presented in the context of head restraints designed to meet the static 
requirements, the option which is relevant to nearly all current head 
restraints.
    The dynamic alternative simply provides a means to facilitate the 
development and use of active head restraints, while ensuring the same 
level of protection as ones meeting the static requirements. For 
reasons discussed above, it was necessary to reduce the head rotation 
limit in order to accomplish this, and there were a variety of other 
reasons why it was necessary to upgrade the dynamic alternative. The 
agency is not requiring active head restraints, and we do not

[[Page 25500]]

believe additional analysis concerning costs and benefits of the 
dynamic alternative is necessary.
    As indicated in the discussion in the final rule preamble, data 
indicate that active head restraints can be designed to comply with the 
12 degree head-to-torso rotation limit. Since the publication of the 
final rule, we have conducted dynamic tests using four different 
manufacturers' active head restraints. The results are shown in Table 
I. Three of the four seats had head-to-torso rotations of less than 7.7 
degrees.\31\ One seat exceeded the 12 degree limit (17.9 degrees). This 
data shows that, in general, active head restraints can perform very 
well in the dynamic option. However, this is a seating systems test 
that assesses the performance of multiple seat characteristics such as 
the seat back compliance and seat back recliner mechanism, in addition 
to the head restraint. So the mere presence of an active head restraint 
does not assure compliance. Also after publication of the final rule, 
it has been reported to the agency that a production Toyota Whiplash 
Injury Lessening (WIL) seat, optimized for rear impacts, but not an 
active head restraint, achieved a head-to-torso rotation of 6 degrees 
when tested to the dynamic compliance option.\32\ The Toyota WIL seat 
shows non-active systems can be designed to pass the test.
---------------------------------------------------------------------------

    \31\ Copies of the test reports will be placed in the docket.
    \32\ See the docket for this document.

        Table I.--NHTSA Testing of MY2006 Active Head Restraints
------------------------------------------------------------------------
                                                           Head-to-torso
                         Vehicle                             rotation
                                                              (deg.)
------------------------------------------------------------------------
Honda Civic.............................................             7.7
Nissan Altima...........................................            17.9
Saab 9-3................................................             4.1
Subaru Outback..........................................             4.1
------------------------------------------------------------------------

    We note that the Alliance requested that if the agency does not 
otherwise change the 12 degree limit, a 10 percent tolerance should be 
added for purposes of compliance.\33\ This would, in effect, change the 
limit to 13.2 degrees. However, the Alliance did not present evidence 
that the 12 degree limit cannot be met by vehicles with active 
restraints. We therefore decline to make this change.
---------------------------------------------------------------------------

    \33\ We note that when NHTSA includes tolerances in the safety 
standards, vehicles or equipment must meet the specified 
requirements at all points within the specified tolerances. Thus, 
tolerances within the safety standards do not provide compliance 
margins.
---------------------------------------------------------------------------

    We do not believe that the fact that the Volvo WHIPS seat does not 
pass the 12 degree limit is a reason to change the requirement. The 
primary reason for including the dynamic test option is to facilitate 
use of active restraint systems that require a certain range of motion 
to work effectively and which, when undeployed, might not meet the 
static test requirements.
    The Volvo WHIPS seat does not present this type of active system. 
It incorporates features in the seat recliner mechanism to help 
optimize rear impact protection, but it does not ``deploy'' as such. We 
have been advised that the Volvo WHIPS seat meets the static test 
requirements.\34\ Therefore, the dynamic test option is not needed to 
permit this type of system.
---------------------------------------------------------------------------

    \34\ In supplemental information submitted to the agency, Ford 
reported a 13 mm backset for the Volvo S80 (Docket No. NHTSA-2004-
19807-25). This is consistent with agency backset measurements of 
the S40, which were well below the backset limit.
---------------------------------------------------------------------------

    We also observe that Ford indicated that IIHS rated all of the 2005 
Volvo models using the WHIPS seat as ``Good.'' However, IIHS published 
a study in April of 2005, through the Highway Loss Data Institute 
(HLDI), which examined the rate of personal injury protection (PIP) 
claims in passenger cars struck in the rear for different vehicle 
classes (by vehicle weight), different types of head restraints 
(active, non-active), and different types of seats (WHIPS, and no 
WHIPS).\35\ The results of the study indicate that for each vehicle 
class, active head restraints outperform non-active head restraints. In 
addition, within each vehicle class, the PIP rates of seats with active 
head restraints rated as ``marginal'' or ``poor'' by IIHS was lower 
than the PIP rates of seats without active head restraints rated as 
``good'' by IIHS. The study indicated that Volvos equipped with WHIPS 
seats did not reduce relative PIP rates when compared to vehicles with 
similar size and weight.
---------------------------------------------------------------------------

    \35\ Insurance Special Report --Head Restraints and Personal 
Injury Protection Losses, (2005). Highway Loss Data Institute 
(HLDI).
---------------------------------------------------------------------------

2. Trigger Point
    The Alliance stated in its petition that there is no provision in 
the dynamic option for a trigger point for a sensor driven deployable 
head restraint and that such a provision should be included. It stated 
that such a specification would be similar to one included in FMVSS No. 
208 for the sled test option, and argued that such a provision should 
be included in the head restraint standard to ensure objective testing.
    In a meeting with NHTSA, BMW argued that for its dynamic head 
restraint design to be adequately tested, a trigger or deployment time 
needs to be part of the test procedure.\36\ The BMW active head 
restraint uses a pyrotechnic design. Once the threshold acceleration is 
sensed, the pyrotechnic element fires and the head restraint moves 
about 40 mm to 60 mm forward, depending on the height adjustment, and 
rotates 9 degrees towards the occupants head.
---------------------------------------------------------------------------

    \36\ Docket No. NHTSA-2004-19807-21.
---------------------------------------------------------------------------

    BMW argued that the half-sine deceleration pulse is not 
representative of the pulse that its vehicle would sense in a rear 
impact. However, it believes the total [Delta]V is acceptable. BMW 
provided a data plot of a rigid barrier striking one of its vehicles at 
35 km/h in comparison to a sled pulse within the FMVSS 202a corridor. 
The slope of the acceleration was much higher for the barrier impact, 
although at approximately 80 ms they both have a 17 km/h [Delta]V. BMW 
stated that its system would deploy in the rigid barrier impact, but 
might not in the sled test. It stated that if it were to adjust its 
algorithm to deploy in the test, it could get deployments in the field 
when it is unnecessary to protect the occupant.
    After considering these requests, we decline to make the requested 
change. As discussed below, we believe that the specified sled pulse is 
representative of one experienced in a crash when the head restraint is 
needed to provide protection. Therefore, we believe the sensors should 
be designed to activate the head restraint in such a situation. We are 
concerned that if the agency specified a trigger point, i.e., specified 
that the head restraint be activated at a specific point in time as 
part of the test procedure, there would be no test of the sensors and 
no assurance that the head restraint would activate during the type of 
crash simulated by the sled pulse.
    We do not consider the provisions of FMVSS No. 208 with respect to 
its sled test as indicative that a trigger point is needed for the head 
restraint sled test. The FMVSS No. 208 sled test was adopted as a 
special measure to help address the problem of aggressive air bags. The 
sled test was adopted to enable vehicle manufacturers to quickly 
depower all of their air bags.
    There are no similar time issues related to active head restraints, 
and manufacturers have time to develop algorithms to ensure that such 
head restraints activate in a timely manner during the sled test, 
without activating

[[Page 25501]]

in situations where deployment is unnecessary. We note that BMW has not 
presented evidence to the agency that this cannot be done with its 
system.
    As to the issue of the representativeness of the crash pulse, we 
believe that the appropriateness of the [Delta]V and average 
acceleration of the FMVSS No. 202a pulse is supported by a 2002 Swedish 
study by Krafft and others. This study examined rear impact crashes 
with crash recorders where crash pulse was a known (66 such 
crashes).\37\ It examined the relationship between whiplash injury risk 
and parameters such as [Delta]V, peak acceleration, average 
acceleration, and average windowed acceleration for 18 ms, 36 ms, and 
80 ms. It found that average acceleration best correlated with whiplash 
injury risk.
---------------------------------------------------------------------------

    \37\ Krafft, M., Kullgren, A., Ydenius, A., and Tingvall, C. 
(2002) Influence of Crash Pulse Characteristics on Whiplash 
Associated Disorders in Rear Impacts--Crash Recording in Real-Life 
Impacts, Traffic Injury Prevention, Vol. 3 (2), pp 141-149.
---------------------------------------------------------------------------

    For most occupants who had whiplash symptoms for longer than a 
month, the mean acceleration of the crash pulse was greater than 4.5g 
and above a [Delta]V of 15 km/h. For this group, the average mean 
acceleration was 5.3 g and the average [Delta]V was 20 km/h. The FMVSS 
No. 202a crash pulse has a 5.6 g average acceleration and 17.3 km/h 
[Delta]V.
    We are including in the Technical Analysis \38\ noted earlier 
additional analysis concerning why we believe that the sled test pulse 
is appropriate.
---------------------------------------------------------------------------

    \38\ ``Technical Analysis Relevant to Petitions for 
Reconsideration to the December 14, 2004 FMVSS 202a--Head Restraints 
Final Rule.''
---------------------------------------------------------------------------

3. Dynamic Angular Measurement
    The Alliance, in reference to the procedure specified in S5.3.9 for 
calculating angular displacement, stated that Part 572 does not specify 
instrumentation for determining the angular position of either the head 
or the torso of the Subpart E dummy. It stated its understanding that 
agency tests have used magnetohydrodynamic (MHD) angular rate sensors 
mounted in the head and torso. The Alliance stated that if the agency 
plans to use these sensors for the FMVSS No. 202a dynamic tests, this 
instrumentation and its mounting (and any related changes to the dummy 
to offset the added mass of the MHD sensors) should be specified in 
Part 572 or in the FMVSS 202a test procedure, along with any algorithms 
that will be used to process the data.
    We note that S5.3.9 does not specify specific instrumentation, but 
does specify that the instrumentation and algorithm to be used is 
capable of determining the relative angular displacement to within one 
degree. While we have considered the Alliance's request, we have 
decided not to specify the specific instrumentation. A variety of types 
of instrumentation can be used to make the specified measurements, and 
we believe that there is no reason to be more specific.
    We have made clarifying changes in the regulatory text to make it 
clear that the Hybrid III dummy is fitted with sensors to measure 
rotation between the head and torso, and that the dummy with the 
sensors is to still meet the specifications in 49 CFR Part 572 Subpart 
E.
4. Seat Back Angle
    We note that the agency was not asked to change the 25 degree seat 
back angle specified for the dynamic test alternative, and are not 
making such a change. Concerns related to the static backset limit and 
comfort are not relevant to the dynamic test. Absent this 
consideration, we believe it is preferable to test seats in a 
consistent way with respect to seat back angle.
5. Technical Amendments
    The Alliance pointed out an incorrect reference in S5.3.7.4. We are 
correcting that reference, from S5.3.7.4 to S5.3.7.5.
    We note that maintaining the 25 degree seat back angle for the 
dynamic test and specifying design seat back angle for all other 
testing requires rearranging the regulatory text. S5.1 previously 
specified the seat back angle for all tests was 25 degrees. We have 
moved this specification to S5.3.4, which deals with the test setup for 
the dynamic test. S5.1 contains a specification that all tests, except 
the dynamic test (S5.3) and the backset for a specific type of head 
restraint not attached to the seat (S5.2.3), be performed at design 
position.
    We are also making two technical clarifications related to seat 
setup. S5.3.4 previously contained specification for the seat cushion 
adjustment for the dynamic test. This has been brought forward to S5 
because it is relevant to the static testing as well. Finally, S5.3.4 
specified that seat cushion and seat back adjustment be made ``without 
using any controls that move the entire seat.'' This prohibition is 
unnecessary and inconsistent with S5, which does not make this 
limitation.

D. Clarification of Removability Requirement

    The final rule provided that head restraints ``must not be 
removable without a deliberate action distinct from any act necessary 
for adjustment'' (S4.5). Several petitioners requested clarification of 
this provision.
    The Alliance stated that the rule is ambiguous for two adjustment/
removal control scenarios. First, it stated that it believes that a 
button that would be pushed to an initial adjustment position to adjust 
head restraint height and which then must be pushed further to a more 
depressed position to permit removal of the head restraint would comply 
with the requirement of providing a ``deliberate action distinct from 
any act necessary for adjustment.'' The Alliance requested confirmation 
that a single actuating device for adjustment and also for head 
restraint removal would comply with the standard when there are two 
distinctive positions for setting of the actuating device to perform 
the different operations of head restraint adjustment and head 
restraint removal.
    Second, the Alliance stated that, in addition, its members are 
unsure whether the new limits on actions to remove head restraints 
would apply to current head restraints that have a control button that 
must be pushed to lower the head restraint, but not to raise it to a 
higher adjusted position. It stated that to adjust the head restraint 
higher, the head restraint is simply pulled upward. The Alliance stated 
that it believes that the combined action of pushing the same button 
used to adjust the head restraint down while pulling the head restraint 
up would constitute a ``deliberate'' action distinct from any act 
necessary for adjustment. It noted that the agency's CTP includes a 
statement that pushing the same button to adjust height and to remove 
the restraint is not permitted. The Alliance stated that it disagrees 
with this interpretation and stated that it is not consistent with ECE 
17.
    DaimlerChrysler and Johnson Controls also raised the same concern 
as the latter one made by the Alliance. DaimlerChrysler suggested that 
the language be reformulated to read: ``The head restraint must not be 
removable without a deliberate action distinct from any act necessary 
for upward adjustment.''
    After considering the petitions for reconsideration, we have 
decided to adopt the language suggested by DaimlerChrylsler. The 
purpose of this provision was to prevent head restraints from 
accidental removal when being adjusted. This is a potential problem 
when the head restraint is being adjusted in an upward direction but 
not a downward direction.
    As to the Alliance's question concerning whether a head restraint

[[Page 25502]]

design with a push button that would be pushed to an initial adjustment 
position to adjust head restraint height and which would be pushed 
further to a more depressed position to permit removal of the head 
restraint would comply with the requirement regarding providing a 
deliberate action distinct from any act necessary for adjustment, the 
answer is no. This assumes, consistent with the language we are 
adopting that was suggested by DaimlerChrysler, that the button would 
permit adjustment in the upward position.
    As we understand the design at issue, the action required for 
adjustment and the action required for removal would be pushing the 
same button. The fact that the button would need to be pushed further 
for one scenario than the other would not be sufficient to make it a 
distinct deliberate action. However, pulling or twisting that same 
button would constitute a distinct action.
    Further, we are aware of designs where the head restraint locks for 
both upward and downward movement and a single button is used to 
release the head restraint for adjustment in either direction. Under 
the new language that same button, activated in the same way, could not 
be used to release the head restraint for complete removal.

E. Height Requirement

    Under the final rule, front seat head restraints must be able to 
achieve a height of at least 800 mm, and front seat and optionally 
provided rear seat head restraints must not be adjustable to positions 
lower than 750 mm. Height is defined as the distance from the H-point 
measured parallel to the torso reference line defined by the SAE J826 
manikin.
    As discussed earlier, the agency's decision to change seat back 
angle from 25 degrees to manufacturer design angle, as part of its 
response to petitions concerning the backset requirement, has a small 
impact on the height requirement. Under the final rule, the same 
specified seat back angle is used for measuring backset and height. In 
order to maintain this, we are specifying manufacturer design angle 
instead of 25 degrees for both requirements. This enables both 
measurements to be taken from the same manikin installation. In 
addition, we are not aware of any reason why different seat back angles 
would be used for the two requirements.
    In the final rule preamble, we stated that there is a decrease in 
measured height of 2 to 3 mm for each degree the seat back is more 
upright. Because the fleet-weighted front seat seat back design angle 
is 23.5 degrees, the decrease in measured height will typically be 
about 3 to 4.5 mm. This means that, on average, head restraints will 
need to be 3 to 4.5 mm taller for front seats as a result of this 
change. Most rear seat backs are not adjustable, so there is 
effectively no change in the averaged required height.
    DaimlerChrysler petitioned the agency to add what it referred to as 
a ``13 mm acceptance tolerance for audit purposes'' to the height 
limit. This would mean reducing the height limit for front seat head 
restraints to 787 mm and rear seat head restraint to 737 mm.\39\ That 
company indicated that such a provision would make the FMVSS No. 202a 
requirement more similar to ECE 17.
---------------------------------------------------------------------------

    \39\ We note that when NHTSA includes tolerances in the safety 
standards, vehicles or equipment must meet the specified 
requirements at all points within the specified tolerances. Thus, 
tolerances within the safety standards are not ``acceptance 
tolerances for audit purposes.''
---------------------------------------------------------------------------

    Johnson Controls requested that the current procedure for 
measurement of head restraint height, using SgRP, be retained. It 
stated that it believes it is inappropriate to utilize an H-point 
reference, which introduces more variation into the determination of 
head restraint height than exists today using SgRP.
    Johnson Controls also addressed the issue of seat cushion 
adjustment. That petitioner stated that there is no reference in the 
final rule for seat cushion adjustment, but that this is covered in the 
CTP, i.e., highest adjustment position of the seat cushion. Johnson 
Controls stated that using the highest position of the cushion to 
determine compliance with head restraint height requirements utilizes a 
position occupied by smaller occupants to establish conformance with a 
height requirement intended to address larger occupants.
    In a July 20, 2005, meeting with NHTSA, Ford requested that the 
agency use SgRP instead of H-point in measuring height.\40\ The 
previous version of FMVSS No. 202 used SgRP, as does ECE 17.
---------------------------------------------------------------------------

    \40\ Docket No. NHTSA-2004-19807-20.
---------------------------------------------------------------------------

    The Alliance noted that the regulatory text in S5.2.1 states that 
the height should be measured using the scale incorporated in the SAE 
J826 manikin. It stated its belief that the agency's intent was to 
specify the headroom probe.
    The Alliance also stated that it believes there is inconsistency 
between the seat back positions specified in S5.1 and those indicated 
in S5.2.1 and S5.2.3. S5.1 refers to an exception to the seat back 
angle specification that is then specified in S5.2.3.9 (backset 
measurement). However, S5.2.1 (height measurement) also has an 
exception to the seat back angle.
    As to the issue of measuring height from H-point or SgRP, the 
agency addressed this subject in the preambles to the NPRM and final 
rule. Use of H-point measures the actual vehicle as manufactured and 
hence the actual protection provided to vehicle occupants. By contrast, 
the SgRP is a theoretical design point in the vehicle and does not 
necessarily represent the actual vehicle build. Therefore, we continue 
to believe that use of H-point is a better approach and decline to 
change to SgRP.
    As to seat cushion adjustment, it is the agency's goal to ensure 
that the specified height requirement is met with the cushion in the 
worst case position, i.e., regardless of how the cushion is adjusted, 
the height limit must be met. As to Johnson Controls' argument that 
this results in a requirement that utilizes a position occupied by 
smaller occupants to establish conformance with a height requirement 
intended to address larger occupants, we agree that it is not 
unreasonable to think that shorter occupants might be biased toward 
adjusting the entire seat with respect to the vehicle interior. 
However, we do not have any data showing that different size occupants 
routinely adjust seat cushion orientation in light of their own height 
or to believe that only small statured occupants would ride with seat 
cushions adjusted to yield a higher height with respect to the seat 
back.
    We note that when the agency performed its study of backset 
measurement variability, discussed earlier, we also assessed height 
measurement variability. In general, the height variability is similar 
to that of backset, but we do not see a reduction in variance by taking 
the average of three measurements. We are including the results of that 
study in the Technical Analysis \41\ discussed earlier.
---------------------------------------------------------------------------

    \41\ ``Technical Analysis Relevant to Petitions for 
Reconsideration to the December 14, 2004 FMVSS 202a--Head Restraints 
Final Rule.''
---------------------------------------------------------------------------

    While we have considered DaimlerChrysler's request that we reduce 
the specified height requirements by 13 mm, we decline to make that 
change. That company did not submit data demonstrating difficulties in 
the meeting the 800 mm height requirement for front seats or the 750 mm 
requirement for rear seats. As discussed earlier, manufacturers 
routinely design their vehicles with a compliance margin to meet 
regulatory requirements. Such margins are intended to address both 
measurement

[[Page 25503]]

variability and build variability. We are not aware of any issues 
concerning undue measurement variability with respect to the height 
requirement. We also note that, unlike the backset limit, small 
differences in height do not raise comfort issues. We therefore decline 
to change the requirement.
    The Alliance is correct that the scale referred to in S5.2.1 is 
more specifically the headroom probe. This is a more appropriate 
designation, and we are revising the language accordingly. We also note 
that the probe by itself cannot be used to directly measure height, but 
must be used in conjunction with, for example, a carpenter's square.
    We also agree with the Alliance that there is inconsistency in 
S5.1, since it refers to an exception to the seat back angle used for 
measurement in S5.2.3 but not the exception stated in S5.2.1. We are 
therefore adding to S5.1 a reference to S5.2.1 indicating that this 
section also has an exception to the general seat back angle provision.

F. Gaps Between Head Restraint and Seat Back

    DaimlerChrysler stated that it is concerned that the test method 
specified for the gap requirement could disallow the ``shingled'' or 
``saddle'' design for head restraints. That company stated that it 
knows of no way to meet the 60 mm gap requirement in S4.2.4 for 
shingled or saddle type retractable head restraints, when using the 
spherical gap measurement procedure in S5.2.4 for gaps between the head 
restraint and seat. DaimlerChrysler stated that these designs currently 
are approved to ECE R17 where a linear gap measurement procedure is 
used. It petitioned that FMVSS No. 202a be harmonized with the ECE R17 
procedure for this specific issue. The Alliance stated that further 
clarification is necessary for the gap measurement.
    After considering the DaimlerChrysler and Alliance petitions, we 
have decided to specify that the gap requirement must be met when the 
gap is measured either by the existing current FMVSS No. 202a procedure 
using a sphere or one based on the ECE 17 measurement methodology. We 
are not aware of any data showing benefits to one methodology over the 
other.
    Also, we are adding a new Figure 4 that we believe will help 
clarify the requirement when using the sphere.

G. Backset and Height Retention (Lock) Tests

    FMVSS No. 202a includes test requirements to help ensure that a 
head restraint that locks in position will maintain this position when 
loaded downward (S4.2.6 and S5.2.6) and rearward (S4.2.7 and S5.2.7).
    For the height retention test, the seat back is initially braced to 
prevent it from moving. A 50 N downward force is applied with the round 
surface of a 165 mm diameter cylinder to establish an initial reference 
position. During the application of this load, the head restraint is 
required to not move more than 25 mm. This is necessary to prevent head 
restraints with very weak locks from displacing to their down position 
and passing the remainder of the test. The downward load is then 
increased to 500 N and is held for 5 seconds. The load is then reduced 
back to 50 N, and the position of the head form is checked to assure 
that it did not have a change from its reference position of more than 
13 mm.
    The backset retention test is somewhat more complicated than the 
height retention test because it is performed in the midst of the 
displacement test. First, the displaced torso reference angle is 
achieved by a 373 Nm moment applied through the back pan. This 
establishes the displaced torso reference line used to test for head 
restraint displacement beyond 102 mm. Then a 37 Nm moment is applied 
with the 165 mm spherical head form to establish an initial reference 
position for the locking test. During the establishment of this initial 
reference position the loading device is not permitted to move more 
than 25 mm. This is necessary to prevent head restraints with very weak 
locks from displacing to a physical stop and passing the remainder of 
the test in that position.
    The moment is then increased to 373 Nm and maintained at that level 
for 5 seconds. It is during the application of this 373 Nm moment that 
the head form must not displace more than 102 mm beyond the displaced 
torso reference line. The moment is then reduced to the 37 Nm 
reference. The head form must return to within 13 mm of the initial 
reference position to verify that the locking mechanism is meeting the 
performance requirement.
    We note that in the test procedure outlined above, the bracing of 
the seat back was introduced in the December 2004 final rule. We stated 
in the final rule preamble that if seat characteristics were not 
accounted for by bracing the seat ``the horizontal displacement may be 
larger because of those characteristics.'' 69 FR at 74867. The return 
to position limit was also increased, relative to the NPRM, from 10 mm 
to 13 mm for the same reason.
    Petitioners raised several issues concerning the backset and height 
retention tests. In the sections which follow, we will address each 
issue and provide our response.
1. Zero-Out Load
    Several petitioners, including the Alliance, DaimlerChrysler, 
Keiper, and Johnson Controls, asked that the agency make a slight 
modification to the test procedures described above. The modification 
involves the loading sequence. They recommended that instead of 
returning to the reference loads of 50 N or 37 Nm after application of 
the peak load, that the load be reduce to zero and then increased to 
the reference loads. They believe this will alleviate much of the 
permanent set associated with upholstery and foam in the head restraint 
that is not a true measure of structural displacement.
    Keiper submitted test data from testing of a Mercedes Benz C-Class 
seat. Under the current procedure the backset retention displacement 
range was 15 to 18 mm, which is outside the 13 mm limit. However, after 
unloading the head restraint and reloading to the reference load, the 
displacement was 2 to 4 mm. Keiper did not indicate whether the seat 
back was braced. DaimlerChrysler submitted data that is subject to a 
claim of confidentiality.
    In order to evaluate this issue, the agency conducted a series of 
tests on eight different make/models of vehicles. The agency performed 
height retention and backset retention tests according to the modified 
procedure suggested by the petitioners. In addition, as part of 
evaluating the appropriate procedure for these tests, the study 
included tests with the seat back braced and not braced. The details of 
the testing are included the Technical Analysis \42\ noted earlier.
---------------------------------------------------------------------------

    \42\ Technical Analysis Relevant to Petitions for 
Reconsideration to the December 14, 2004 FMVSS 202a--Head Restraints 
Final Rule.''
---------------------------------------------------------------------------

    After considering the arguments and data submitted by manufacturers 
and the results of our testing, we have decided to grant the 
petitioners' requests in this area. Based on the testing performed to 
the modified test procedure, we conclude that completely removing the 
load on the head restraint before returning to the reference load 
improves the test results in a statistically significant way.
2. Five Second Hold Time
    The Alliance petitioned the agency to specify a peak load hold time 
of 5 to 6 seconds and have the measurement taken during the hold 
period. The regulation currently states the hold time will be at least 
5 seconds. The Alliance argued that the hold times for this and

[[Page 25504]]

other aspects of the loading procedure may affect the results.
    After considering this issue, we believe that the request to modify 
the hold time for the maximum load values (S5.2.6(c), S5.2.7(a)(6) and 
S5.2.7(b)) from a minimum of 5 seconds to 5.5  0.5 seconds 
has merit. We also believe that there should be a tolerance on the hold 
times for the initial application of the reference loads (S5.2.6.(b)(2) 
and S5.2.7(a)(5)) and on the times after which the displacement 
measurement should be made (S5.2.6(e) and S5.2.7(a)(8)). We are 
therefore making changes in the regulatory text to reflect these 
decisions.
3. Request for Elimination of Vertical Height Retention Test
    Johnson Controls argued that the vertical height retention test is 
not justified and should be eliminated. It believes that the agency's 
justification for the 500 N load was derived from the force component 
of lateral (rearward) displacement. Johnson Controls stated that 
although its customers prescribe loads that a head restraint must 
resist vertically, these are to account for the loading a person might 
put on the head restraint as they enter or exit the vehicle and these 
loads are much less than 500 N.
    In explaining the height retention force of 500 N in the preambles 
to the NPRM and final rule, we stated that it is representative of the 
peak loads likely to be encountered in moderate to severe rear impacts. 
We noted that the average upper neck shear forces in a Hybrid III 50th 
percentile male dummy in FMVSS No. 301 rear impacts was about 350 N. We 
surmised that this shear load was representative of the loading on the 
head restraint although we did not do an analysis to determine the 
direction of the loading.
    Since the final rule was published, we have made a more thorough 
examination of head restraint loading based on the dummy neck loads 
measured in rear impact crash and sled tests. We have presented this 
analysis in a technical report.\43\ The test type and dummy size that 
we have the most data for is the 50th percentile male dummy in a FMVSS 
No. 301 impact. For 23 cases, the average downward force was 539 N. We 
believe these and the other data presented in the technical report show 
the need for and appropriateness of the 500 N vertical load. We 
therefore decline to adopt the request of Johnson Controls.
---------------------------------------------------------------------------

    \43\ This analysis has been presented to the Informal Working 
Group on Head Restraints in connection with the ongoing development 
of a GTR and can be found at http://www.unece.org/trans/doc/2005/wp29grsp/HR-02-08e.pdf.
---------------------------------------------------------------------------

4. Pre-Load Displacement Limit
    The Alliance stated there are some mechanical active head restraint 
designs that cannot meet the 25 mm pre-load displacement limit during 
the backset retention test (S4.2.7 and S5.2.7). It petitioned the 
agency to increase this limit to 35 mm or remove it completely. It 
argued that this requirement places a limitation on manufacturers' 
ability to provide active head restraints.
    DaimlerChrysler stated that it has a rear seat head restraint 
design that rotates without locking, for occupant comfort. It called 
these ``inclinable designs'' and said that they displace during the 
preload and cannot meet the 25 mm limit on displacement during the 
preload of the height retention test (S4.2.6 and S5.2.6). It petitioned 
the agency to increase the preload limit for these types of head 
restraints to 50 mm.
    As discussed below, we have decided to deny the requests of both 
petitioners. However, to help accommodate active head restraint 
systems, we are making a change in the test procedure to permit active 
systems to be fixed in their undeployed position during the position 
retention testing.
    The Alliance stated that there are advanced active head restraints 
that, due to their mechanical nature, displace more than 25 mm during 
the preload of the backset retention test. Therefore, it requested a 35 
mm limit.
    We note that the agency anticipated that there may be advanced 
designs which, by their active nature, are unable to pass the static 
test requirements in their undeployed positions. This is why the 
dynamic compliance option was provided.
    However, while the dynamic compliance option is specifically in 
place for active systems, it has never been our intention to exclude 
active systems from certifying through the static option. However, the 
agency has emphasized that such static compliance must be in the 
undeployed condition. See 69 FR 74854.
    Based on our desire to not exclude the possibility of active 
systems being certified to the static option, we have decided to permit 
active systems to be fixed in their undeployed position during the 
retention tests. We are including a specific manufacturer option to 
this effect in FMVSS No. 202a.
    We believe that the concern raised by the Alliance is brought about 
by the way active systems function and that the option to fix them in 
their undeployed position during the retention tests will resolve that 
concern. Therefore, we are not changing the 25 mm limit to 35 mm as 
requested by that petitioner.
    DaimlerChrysler requested an increase of the preload displacement 
limit in the height retention test from 25 mm to 50 mm because of a 
design that rotates for comfort. However, head restraint users will not 
know whether adjustment positions are for comfort or for improved 
whiplash protection. Moreover, regardless of whether a manufacturer 
intends a head restraint position to be for comfort or to provide 
improved whiplash protection, there are safety benefits for having the 
adjustment position selected by the user lock in place. The head 
restraint design, as described, appears to have non-locking positions. 
The agency included the preload displacement limit to address such 
systems. We are therefore not adopting the change recommended by 
DaimlerChrysler.
5. Seat Back Bracing
    As discussed above, as part of the agency's additional testing and 
evaluation concerning the appropriate procedure for the height 
retention and backset retention tests, it included tests with the seat 
back braced and not braced.
    The agency indicated in the preamble to the final rule that it 
intended to alter the position retention tests to allow the seat back 
frame to be braced. 69 FR at 74867. However, a provision to this effect 
was not included in the regulatory text.
    We note that some concerns were expressed in the context of the 
development of a GTR that bracing the seat back during these tests does 
not provide a load path that would be seen in real world use.
    As part of our additional testing, we studied the bracing of the 
seat back. The discussion below refers to testing that incorporates a 
zero load in the loading sequence. The testing showed that although 
there was a small reduction in the average displacement value for the 
braced condition when the loading was returned to the reference value, 
this difference was not statistically significant. However, we did find 
that bracing the seat back reduced the peak displacement by an average 
of about 18.5 mm and that this was significant at a 90% level of 
confidence. It was not our intention to reduce the stringency of this 
requirement by bracing the seat back.
    As part of reevaluating the test procedure for these tests in 
response to petitions for reconsideration, we have decided that the 
seat backs should not be braced for these tests. We are also making 
this change as part of

[[Page 25505]]

maintaining consistency with changes we are making in the test 
procedure for the energy absorption test, which are discussed below. 
There is no need to change the regulatory text, given that the agency 
omitted adding a specification for bracing in the final rule.

H. Energy Absorption Test and Seat Back Bracing

    Under the energy absorption test requirement (S4.2.5 and S5.2.5), a 
6.8 kg mass strikes the head restraint at 24.1 km/h, and the 
deceleration of the impactor must not be more than 80g.
    The Alliance stated that it was concerned that S5.2.5 of the 
regulatory text specifies that this test is to be performed with the 
seat back ``rigidly fixed'' without any further clarification of how it 
is fixed. It stated that the methodology as to how the seat back is 
fixed may affect the test results. It requested there be no seat back 
bracing.
    The Alliance also stated that S4.2.5 and S5.2.5 do not specify a 
seat back angle for the test. It stated that it believes that it is the 
agency's intent to perform the tests consistent with ECE 17, i.e., with 
the seat back at design position. It requested that this be explicitly 
stated in the regulation.
    The agency has performed an evaluation of various energy absorption 
test methods. This evaluation is included in the Technical Analysis 
previously cited.\44\
---------------------------------------------------------------------------

    \44\ ``Technical Analysis Relevant to Petitions for 
Reconsideration to the December 14, 2004 FMVSS 202a--Head Restraints 
Final Rule.''
---------------------------------------------------------------------------

    In testing performed by the agency using a linear impactor, bracing 
the seat back resulted in a slightly more severe (about 10%) outcome. 
However, this difference was not statistically significant. Also, 
removal of the seat back bracing will simplify the test procedure. We 
have therefore decided to make the change requested by the Alliance.
    We do not agree with the Alliance that FMVSS No. 202a was unclear 
about the seat back angle to be used in this test. Under the final 
rule, S5.1 stated that, except in S5.2.3, the seat back angle must be 
the position closest to 25 degrees.
    However, given that we are changing from 25 degree seat back angle 
to design seat back angle for the backset and height requirements, we 
believe it is appropriate for purposes of consistency to also use 
design seat back angle for this test. Accordingly, we are granting the 
Alliance's request to that effect.

I. Head Restraint Clearance

    In order to accommodate vehicles with low rooflines, FMVSS No. 202a 
permits a lower minimum height for head restraints for front outboard-
designated seating positions to allow a maximum of 25 mm of vertical 
clear space between the top of the front head restraint and the 
roofline. It similarly permits a lower minimum height for rear outboard 
seating positions equipped with optional head restraints to allow a 
maximum of 25 mm of vertical clear space between the top of the rear 
head restraint and the roofline or the backlight.
    In petitioning for reconsideration, the Alliance expressed concern 
that the agency had not defined the term ``roofline.'' It stated its 
belief that the agency intended to measure clearance to the inside of 
the headliner, consistent with ECE 17 practice. The Alliance argued 
that without clearance to the inside of the headliner, the head 
restraints would damage the energy absorbing capability of the 
headliner. The Alliance requested that the agency replace the term 
``roofline'' with ``interior surface of the roof'' to clarify that the 
intent is the same as ECE 17, or to define the term ``roofline'' as the 
interior surface of the roof of the vehicle.
    The Alliance argued that for convertibles, the clearance to rear 
seat head restraint clearance needs to be 50 mm to allow for 
articulation of the folding top mechanism.
    DaimlerChrysler made similar requests in its petition for 
reconsideration. However, in a June 8, 2005 with NHTSA, DaimlerChrysler 
requested that the rear seat clearance for convertibles be 10 mm during 
the folding phase of a convertible roof motion.\45\ It showed a diagram 
of a vehicle design that had a 13 mm clearance during folding of the 
roof. This same design had 80 mm of clearance when the roof was in 
place.
---------------------------------------------------------------------------

    \45\ Docket No. NHTSA-2004-19807-13
---------------------------------------------------------------------------

    After considering the petitions for reconsideration, we have 
decided to adopt changes along the lines suggested by the Alliance. As 
to the definition of roofline, it was always the agency's intention to 
measure the roofline/backlight clearance from the interior surface of 
the vehicle rather than from the exterior surface. The latter would be 
unnecessarily complex and have no relevance to the head restraint 
dimensions. Accordingly, in the relevant portions of regulatory text we 
are replacing the term ``roofline'' with ``interior surface of the 
vehicle at the roofline,'' and ``backlight'' with ``interior surface of 
the backlight.''
    On the issue of clearance for convertibles, we note that there are 
differences in the relief requested by the Alliance and the relief 
requested by DaimlerChrysler in its later request. The Alliance 
requested the agency to increase the allowed gap with the roof in place 
from 25 to 50 mm, and DaimlerChrysler requested that the agency provide 
10 mm of clearance as the roof folds.
    DaimlerChrysler presented a design with about 10 mm clearance when 
folding and 80 mm when in place. One might then conclude that, at a 
minimum, if the head restraint had essentially no clearance when the 
roof was folding, the in-place clearance would need to be 70 mm for 
this design.
    The agency does not have independent data on convertible geometry. 
However, we believe that the argument that relief is needed appears 
reasonable. We have decided to grant the relief requested by the 
Alliance. We are not granting the later request made by 
DaimlerChrysler. That request would result in a greater reduction in 
stringency. We do not believe that a single design is sufficient to 
demonstrate a need for greater relief.

J. Width of Head Restraints for Certain Seats

    Johnson Controls petitioned for reconsideration of the retention 
(from the earlier version of FMVSS No. 202) of the 254 mm width 
requirement for outboard designated seating positions for front rows 
with three designated seating positions. That company stated that it 
believes that the head restraint width requirement for these designated 
seating positions should be 170 mm, the same width as required by ECE 
17 standard.
    Johnson Controls argued that the distinction between bench and 
bucket seats that drove the difference in width requirements no longer 
exists. It also stated that the added width is not subject to any 
performance requirements.
    The petitioner stated that, in support of retaining the 
requirement, the agency said that front outboard non-bench seats have a 
defined contour that better prescribe occupant seating position 
relative to the head restraint than bench seats, occupants seated on 
bench seats are freer than occupants of single seats to position 
themselves so that they are not directly in front of head restraint, 
and a bench head restraint needs to be wider to assure that the head 
restraint will be behind the occupant in event of a crash.

[[Page 25506]]

    Johnson Controls argued that, based on a survey it conducted, less 
than 1.4 percent of front seats offered on the market today are bench 
seats where front outboard seating positions have no contour. It also 
argued that extra width is typically trim and foam which has no 
demonstrated ability to achieve goals of prevent neck hyperextension as 
well as smaller rotations of the neck.
    After considering the request of Johnson Controls, we have decided 
to not make the change requested. We note that the agency addressed 
this issue in both the NPRM and final rule preambles.
    As we discussed in the final rule preamble, the 254 mm width 
requirement at issue has been effect since January 1, 1969. We stated 
that we were not aware of any evidence showing that the present level 
of protection should be reduced. We stated that we decided to maintain 
wider head restraints for front bench-type seats because wider head 
restraints tend to better reduce relative head-to-torso motion in off-
axis impacts.
    After considering Johnson Controls' petition, our view remains the 
same. Johnson Controls did not provide evidence that wider head 
restraints do not provide benefits or that they do not better reduce 
relative head-to-torso motion in off-axis impacts.
    DaimlerChrysler requested clarification concerning how this 
requirement applies to a three-passenger first row option with a 
walkway between the driver and the two-passenger seat to the driver's 
side. That company stated that it interprets the two-passenger seat to 
have two outboard seating positions by definition so that the width 
requirements for the head restraints is 170 mm and not the 254 mm 
requirement.
    DaimlerChrysler's suggested interpretation is incorrect. S4.2.2 
specifies that the lateral width of the head restraint for front 
outboard designated seating positions in a vehicle with a front center 
designated seating position must be not less than 254 mm. The term 
``outboard designated seating position'' is defined at 49 CFR Part 571, 
and the inboard seating position on the two-passenger seat is not 
within that definition. Since the vehicle has a front center designated 
seating position, the two front outboard designated seating positions 
must have a width of not less than 254 mm.

K. Option To Comply With ECE 17

    The Alliance stated that it appreciates the option in FMVSS No. 202 
that permits compliance with ECE R17 until September 1, 2008 as an 
option. The Alliance stated, however, that the agency has ``no test 
procedures for its contractors to use in auditing compliance to an ECE 
regulation.''
    The Alliance recommended that NHTSA publish a policy statement 
that, for purposes of this option, the Technical Service organization 
type approval granted for the applicable system to the vehicle 
manufacturer who selects this option can be used for demonstrating 
compliance to FMVSS 202. It stated that, as an alternative, the agency 
would have to develop and publish an official and detailed Test 
Procedure for the ECE R17 requirements itemized in FMVSS No. 202.
    We note that, given the relatively short duration of this option, 
NHTSA does not plan to develop a Laboratory Test Procedure for this 
option. We also decline to adopt the policy statement suggested by the 
Alliance.
    Under the Safety Act, vehicle manufacturers are required to certify 
that their vehicles comply with all applicable Federal motor vehicle 
safety standards. They do not certify compliance with Laboratory Test 
Procedures.
    NHTSA's Office of Vehicle Safety Compliance provides a CTP for the 
use of its contractor laboratories. The agency includes the following 
note at the beginning of these procedures:

    The OVSC Test Procedures are prepared for the limited purpose of 
use by independent laboratories under contract to conduct compliance 
tests for the OVSC. The TPs are not rules, regulations or NHTSA 
interpretations regarding the FMVSS. The TPs are not intended to 
limit the requirements of the applicable FMVSS(s). In addition the 
TPs may be modified by the OVSC at any time without notice, and the 
COTR may direct or authorize contractors to deviate from these 
procedures, as long as the tests are performed in a manner 
consistent with the FMVSS itself and within the scope of the 
contract. TPs may not be relied upon to create any right or benefit 
in any person. Therefore, compliance of a vehicle or item of motor 
vehicle equipment is not guaranteed if the manufacturer limits its 
certification tests to those described in the TP.

    A CTP does not need to be in place in order for a manufacturer to 
certify compliance with a particular standard or option within a 
standard. Also, a CTP does not need to be in place in order for the 
agency to enforce a particular standard or selected option within a 
standard. It is therefore unnecessary for the agency to adopt either of 
the alternatives suggested by the Alliance.

L. Temperature and Humidity Specifications

    The Alliance stated that FMVSS No. 202a should have temperature and 
humidity specifications in order to provide an objective test 
procedure. That organization stated that it could not find any humidity 
specifications, even though these environmental limits are included in 
most FMVSS test procedures.
    The Alliance stated that the OVSC Laboratory Test Procedure 
specifies a temperature range of 19 to 26 degrees C, which the Alliance 
said is a much broader range than vehicle and seat manufacturer's test 
facilities experience. The Alliance stated that because the flexibility 
of seating foam and trim varies with temperature, it recommends 
adopting the same limits that have been used for many years for FMVSS 
No. 208 tests using the Hybrid III dummy. It argued that these 
temperature and humidity limits should be applied to dynamic tests, 
quasi-static force tests, and static measurements. The Alliance did not 
provide data concerning the extent to which seating foam may vary 
temperature or humidity.
    In responding to the Alliance's request, we note that we do not 
believe that the quasi-static force tests and static measurements 
included in FMVSS No. 202a are comparable to the FMVSS No. 208 tests 
using the Hybrid III dummy. The agency includes certain environmental 
limits in FMVSS No. 208 related to the Hybrid III dummy because the 
test dummy itself is sensitive to environmental conditions. However, 
there is no reason to believe that the HRMD is sensitive to 
environmental conditions because it is a purely mechanical measuring 
tool. Moreover, we believe that head restraints should provide 
protection in the wide range of conditions experienced in the real 
world.
    At the same time, we recognize that the inclusion of a temperature 
range improves the objectivity of the standard, particularly given the 
Alliance's argument that the flexibility of seating foam may vary with 
temperature. Without a specification, for example, it is not clear 
whether the agency might conduct tests at very low winter temperatures 
or very hot summer temperatures.
    After considering this issue, we have decided to specify a 
temperature range of 18 to 28 degrees C (64.4 to 82.4 degrees F). This 
is representative of the interior temperatures at which vehicles are 
routinely operated. We note that the range is slightly wider than that 
included in the current version of the Laboratory Test Procedure. The 
Laboratory Test Procedure is not the same as the standard, and it is 
not uncommon for the agency to include narrower conditions in the 
Laboratory

[[Page 25507]]

Test Procedure than those specified in the standard.
    We are not specifying conditions related to humidity. No 
information has been provided showing a need for such specifications, 
and vehicles are routinely operated at wide ranges of humidity.
    Finally we are adding a test condition to the dynamic test which 
provides that the stability test temperature of the test dummy is at 
any temperature level between 69 degrees F and 72 degrees F, inclusive. 
This is the same condition as specified for FMVSS No. 208.

M. Owner's Manual Requirements

    The Alliance petitioned the agency to modify requirements for the 
owner's manual. First, that organization raised concerns about a 
requirement in S4.7.1 that the owner's manual for each vehicle must 
emphasize that all occupants, including the driver, should not operate 
a vehicle or sit in a vehicle's seat until the head restraints are 
placed in their proper positions in order to minimize the risk of 
severe injury in the event of a crash. The Alliance argued that this 
requirement overstates the importance of head restraint adjustment.
    The Alliance stated that while proper adjustment of head restraints 
is desirable to improve their effectiveness in reducing whiplash 
injuries--Abbreviate Injury Scale (AIS) 1 injuries--the agency has not 
presented data indicating that proper positioning minimizes the risk of 
severe injuries. That organization stated that severe injuries are 
generally considered to be injuries of AIS 3 or greater. It requested 
that the agency revise S4.7.1 to state that the owner's manual for each 
vehicle must emphasize the importance of properly adjusting head 
restraints to reduce the risk of injury.
    In considering the Alliance's request in this area, we note that 
while the agency's benefits analysis only accounts for whiplash (AIS 1 
neck) injury, we believe that there is a protective effect against 
high-order neck injuries in higher speed rear impacts. However, we 
agree that based on the frequency of injury the primary benefits of 
proper positioning head restraints are in AIS 1 injuries. We also 
believe that most consumers are not aware of the differences between 
different levels of AIS injuries or the terminology used to describe 
such injuries.
    In light of the most frequent injuries addressed by proper 
positioning of head restraints--AIS 1 injuries--and the terminology 
ordinarily used to describe such injuries, we are removing the term 
``severe'' from S4.7.1 and replacing it with the word ``neck.'' We 
believe that the addition of the word ``neck'' will help draw 
occupants' attention to the importance of proper adjustment of head 
restraints in much the same way as the word ``severe,'' while avoiding 
inconsistent use of a term. We are not otherwise shortening the 
language, since we believe that it is important for all occupants, 
including the driver, to not operate a vehicle or sit in a vehicle's 
seat until the head restraints are placed in their proper positions in 
order to minimize the risk of neck injury.
    The Alliance also expressed concerns about requirements related to 
instructions for head restraint adjustment. S4.7.2(d) requires each 
owner's manual to describe in an easily understandable format the 
adjustment of the head restraints and/or seat back to achieve 
appropriate head restraint position relative to the occupant's head. 
This discussion must include, at a minimum, accurate information on the 
following topics:
    (1) A presentation and explanation of the main components of the 
vehicle's head restraints.
    (2) The basic requirements for proper head restraint operation, 
including an explanation of the actions that may affect the proper 
functioning of the head restraints.
    (3) The basic requirements for proper positioning of a head 
restraint in relation to an occupant's head position, including 
information regarding the proper positioning of the center of gravity 
of an occupant's head in relation to the head restraint.
    The Alliance argued that the intent of item (2) is unclear. It 
stated that except for adjustment, and possibly removal and 
reinstallation, customers do not expect any ``basic requirements'' to 
``operate'' head restraints. That organization also stated that 
adjustment, removal and reinstallation are covered elsewhere. The 
Alliance asked whether this provision is intended to address head 
restraints that fold or retract either automatically or manually.
    In response, we note that although the issues of adjustment, 
removal and reinstallation are covered by other provisions, a head 
restraint may have other modes of operation. Folding and retracting are 
examples of these modes. This provision is intended to ensure that 
users have clear information on all the necessary requirements for 
proper operation.
    The Alliance also argued that item (3) appears to be inconsistent 
with S4.7.2(d) because most customers do not understand the center of 
gravity of an occupant's head. That organization stated that it is not 
practicable to describe in an easily understandable format the 
adjustment of the head restraint in relation to the center of gravity 
of the occupant's head. It suggested that (3) simply state the basic 
requirements for proper positioning of a head restraint.
    We disagree with the Alliance that reference to the head restraint 
adjustment with respect to the head CG is inconsistent with easily 
understandably instructions. However, we believe it is appropriate to 
permit manufacturers the flexibility to provide instructions which 
reference other anatomical landmarks such as the tops of the ears, 
eyebrow, etc. We are therefore revising this provision to that effect.

N. Nature of Standard

    Syson-Hille stated that while it seems reasonable to upgrade FMVSS 
202, it believes that the agency is failing to appropriately address 
the whiplash issue. It argued that as long as seats continue to 
collapse in rear impacts, head restraints will continue to be 
ineffective. Syson-Hille stated that until the seat ``systems'' problem 
is addressed, neither the whiplash problem, nor the failure of seats to 
appropriately manage rear collision energy will be resolved. It stated 
that NHTSA should combine FMVSS No. 202 and No. 207 to form a seat 
``systems'' test.
    In response to this request, we note that we stated the following 
in the final rule preamble:

    In the future stages of our efforts to improve occupant 
protection in rear impacts,\46\ NHTSA intends to evaluate the 
performance of head restraints and seat backs as a single system to 
protect occupants, just as they work in the real world, instead of 
evaluating their performance separately as individual components. 
Accordingly, in making our decisions about the upgraded requirements 
for head restraints in this final rule, we sought, e.g., through 
upgrading our dynamic test procedure option, to make those 
requirements consistent with the ultimate goal of adopting a method 
of comprehensively evaluating the seating system.
---------------------------------------------------------------------------

    \46\ As part of this effort, NHTSA issued a final rule upgrading 
the performance of vehicle fuel systems in rear impacts. (68 FR 
67068, December 1, 2003).

    Syson-Hille's request that we develop a seat systems test that 
considers the spectrum of rear impact severity is not within the scope 
of this rulemaking. We therefore decline to adopt its request. We note 
that the dynamic compliance option does provide a system test at an 
impact speed where whiplash injury is likely. In addition, as indicated 
in the paragraph from the final rule preamble cited above, the agency 
plans to

[[Page 25508]]

continue its efforts to improve occupant protection in rear impacts, 
including considering methods of comprehensively evaluating the seating 
system. For now, for reasons discussed in this document, the NPRM and 
final rule preambles, and the agency's regulatory impact analyses, we 
believe the upgraded head restraint standard will make a significant 
contribution toward reducing whiplash injuries.

O. Leadtime

    Under the final rule, the upgraded standard becomes mandatory for 
all vehicles manufactured on or after September 1, 2008. However, as 
indicated above, the agency previously extended the compliance date for 
the rear seat requirements to September 1, 2010.
    The petitioners' request for additional leadtime was not limited to 
the rear seat. The Alliance stated that while the date set forth in the 
final rule appears to provide more than three years leadtime, it is 
concerned that that leadtime will be subsumed during the period 
petitions for reconsideration are before the agency.
    The Alliance also stated that while it considered the final rule 
and potential issues for reconsideration, the agency published a test 
procedure previously unavailable. (This was apparently referring to the 
OVSC Laboratory Test Procedure or CTP.) The Alliance also claimed that 
other test procedures necessary to complete the final rule have not 
been made public, significantly limiting manufacturers' ability to 
assess the final rule and its impact on their respective vehicle 
fleets. The Alliance argued that test procedures are an integral part 
of the rulemaking process and must be available to the public during 
the entire rulemaking process beginning with the NPRM.
    The Alliance stated that if the issues resolved in its petition 
were not resolved by September 2005, its members would no longer have 
adequate leadtime for some required changes. It stated that minor 
adjustments to backset can be made relatively quickly, but other 
changes are much more time-consuming. We note that one item the 
Alliance cited, development of mechanisms that allow conversion of 
passenger compartments to cargo areas, relates to rear seats. The 
Alliance also stated that developing and incorporating new active head 
restraint mechanisms requires a long leadtime.
    The Alliance also stated that certain vehicle models that are past 
final design release will continue in production beyond September 1, 
2008, but would require extensive changes to comply with FMVSS No. 
202a. It requested that in order to permit manufacturers to implement 
the required changes with the start of a new model cycle rather than at 
the end of the current model design, NHTSA should modify the compliance 
date to require 80 percent compliance with FMVSS No. 202a for the first 
year and 100 percent beginning the second year, with carry-forward 
credits.
    Ford also expressed concern about the amount of time that it 
anticipated would be taken to address issues raised in the petitions 
for reconsideration. It stated that it cannot begin to make vehicle 
design changes necessary to comply with the rule, especially those 
involving retractable head restraints that raise significant safety 
issues, until these issues have all been resolved. Ford stated that it 
believes that the three year leadtime should not begin to run until all 
petitions have been resolved and all test requirements have been 
finalized. Like the Alliance, DaimlerChrysler requested an 80 percent/
100 percent phase-in, with carry-forward credits.
    In responding to the petitions for reconsideration concerning 
leadtime, we begin by noting two things. First, under 49 CFR 553.35, 
the filing of a petition for reconsideration does not stay the 
effectiveness of the rule unless the Administrator so provides. 
Accordingly, once a final rule is published in the Federal Register, 
manufacturers have the responsibility to take steps to comply with that 
rule as it is issued, including its compliance date, unless and until 
the agency changes the rule. The agency will not change the compliance 
date of a rule to account for situations where a manufacturer either 
simply assumes that its petition for reconsideration will be granted or 
decides not to take actions to comply with a standard until such time 
as the agency responds to its petition.
    Second, we disagree with the Alliance's apparent argument that CTPs 
are an integral part of the rulemaking process. They are not. As 
discussed earlier, vehicle manufacturers are required to certify that 
their vehicles comply with all applicable Federal motor vehicle safety 
standards. All necessary test procedures for certification are included 
in the standards themselves (sometimes by incorporation by reference or 
citation to other portions of the CFR).
    In considering the petitioners' requests for additional leadtime, 
we note that the agency provided about three and one-half years 
leadtime in the final rule. Moreover, as a result of our earlier 
partial response to the petitions, we provided five and one-half years 
leadtime for the rear seat requirements. We believe that these 
requirements, particularly the ones related to non-use positions, 
represent the most difficult technical challenges.
    After considering the petitions, we have decided to provide some 
additional leadtime for the front seat requirements, primarily in light 
of the changes made in this final rule. The change in seat back angle, 
while generally providing greater flexibility with respect to the 
backset limit, has an impact on the height requirement. This could, in 
some cases, necessitate design changes. Also, while the various changes 
made in this document are relatively minor, manufacturers may need to 
re-test seats in order to ensure that their vehicles comply with the 
standards.
    For the front seat requirements, we have decided to provide one 
additional year of leadtime and also establish a one-year phase-in with 
an 80 percent requirement. We are not providing for carry-forward 
credits. In addition to providing flexibility with respect to any minor 
design changes that may be needed as a result of the changes made by 
this final rule, the additional leadtime we are providing also 
accommodates the concerns identified by manufacturers concerning 
implementing changes with the start of a new model cycle rather than at 
the end of the current model design.
    As indicated earlier, we previously delayed the compliance date for 
head restraints voluntarily installed in rear outboard designated 
seating positions from September 1, 2008 until September 1, 2010. As 
part of completing our response to the petitions, we have decided to 
also establish a one-year phase-in with an 80 percent requirement for 
these vehicles.
    As indicated above, we believe that the rear seat requirements, 
particularly the ones related to non-use positions, represent the most 
difficult technical challenges. The one-year phase-in will provide 
additional flexibility in meeting these challenges. This 80 percent 
requirement applies to the production year beginning on September 1, 
2010 and ending August 31, 2011. We note that since the rear seat 
requirements apply only to vehicles with voluntarily installed rear 
head restraints, the 80 percent figure is calculated solely with regard 
to vehicles with rear head restraints.
    As with other phase-ins, we are establishing the usual reporting 
requirements.

[[Page 25509]]

P. Technical Amendments and Typographical Corrections

    In the section above on the dynamic optional test, specific 
technical amendments were described. We are also making several 
technical amendments as a result of our own review of the entire 
regulatory text. In Part 571.202 we are making the following revisions. 
We are adding the term GVWR to S2 and S4.1. In S4.1 we are changing the 
reference to S4.3 and S4.4 to S4.4 and S4.5. For Part 571.202a, in 
S5.2.7(a)(5) we are changing the reference to S5.2.7(4) to 
S5.2.7(a)(4).
    Also, in a submission dated February 1, 2007, the Alliance 
requested a technical correction related to the agency's March 2006 
rule delaying the date on which manufacturers must comply with the 
requirements applicable to head restraints voluntarily installed in 
rear outboard designated seating positions. While the Alliance believed 
the preamble was clear as to the agency's intent, it expressed concern 
that the changes made in the regulatory had the effect of delaying some 
but not all of the requirements for rear head restraints. To ensure 
clarity, we are making technical amendments to S2.1 and S4.1 to 
eliminate any doubt that all of the requirements for rear head 
restraints are delayed.
    In addition, typographical errors have been corrected in Part 
571.202a. These include elimination of extra spaces, adding an 
underline and punctuation correction. The following sections are 
affected: S2.2(a), S2.2(b), S4, S4.2.1(a)(2), S4.3.1, S5.2.5(a), 
S5.3.5, S5.3.7.1, S5.3.7.2, S5.3.7.3, S5.3.7.5, S5.4(a)(1), S5.4(a)(4).

VII. Kongsberg Petition for Rulemaking

A. Summary of Petition

    On November 10, 2005, Kongsberg Automotive submitted a document to 
NHTSA that it characterized as a petition for reconsideration of the 
head restraint final rule. However, since this was not submitted within 
the required timeframe for petitions for reconsideration, our 
regulations provide that it is treated as a petition submitted under 49 
CFR Part 552, rather than a petition for reconsideration.
    The majority of arguments from Kongsberg concerning the final rule 
pertain to issues discussed extensively in our response to the timely 
petitions for reconsideration. However, in some cases, the relief 
sought is unique and not requested by others in petitions for 
reconsideration. After considering these requests carefully, the agency 
has decided to deny the Kongsberg rulemaking petition. Below we discuss 
each of the issues raised by Kongsberg and the agency response.

B. Effective Backset

1. Petition
    The petitioner described the term ``effective backset'' as the 
combination of the backset measurement made in FMVSS No. 202a and the 
head restraint displacement measured during application of the initial 
reference moment on the head restraint during the backset retention 
test. The final rule limits on these two requirements are 55 mm for 
backset and 25 mm for the reference moment displacement. The petitioner 
requested that the agency replace the backset criterion of 55 mm with 
an ``effective backset'' limit of 80 mm. It stated that having separate 
requirements for backset and initial displacement in the retention test 
does not drive design changes towards optimization.
2. Agency Response
    The agency has discussed in detail in this document and in the NPRM 
and final rule preambles and accompanying agency analyses the 
scientific basis for the backset limit and the expected benefits. We 
have also discussed the rationale for the backset retention test. 
Specifically, we have explained that the limit on displacement during 
the initial application of the reference moment of 37 Nm is necessary 
to prevent head restraints with very weak locks from displacing to a 
physical stop and passing the remainder of the test in that position.
    In its request concerning an ``effective backset'' requirement, the 
petitioner recommends adding 25 mm to the backset value to account for 
this initial displacement under the reference load. Thus, depending on 
the initial displacement value, a head restraint could have a range of 
acceptable backset values between 55 mm (if the displacement was 25 mm) 
and 80 mm (if the displacement was 0 mm). The petitioner did not 
provide any data as to the expected benefits that might accrue from a 
change to an ``effective backset'' requirement or any alternative 
methodology for estimating these benefits. The petitioner implies this 
change would result in optimized designs, but does not support this 
contention.
    In testing of seven different vehicle model seats to the backset 
retention test, the agency found the average initial displacement was 
approximately 15 mm when a head restraint was exposed to the 37 Nm 
reference moment.\47\ Assuming an average displacement of 15 mm for the 
entire vehicle fleet, the requested effective backset approach would 
result in a 10 mm increase in backset limit or an equivalent backset of 
65 mm. The agency's methodology for calculating benefits related to 
improved backset does not consider the initial displacement of the head 
restraint. Using the agency's methodology for estimating benefits, the 
recommended ``effective backset'' approach would result in a 36 percent 
loss of expected benefits estimated in the 2004 final rule. Moreover, 
it is possible that manufacturers might redesign head restraints to 
reduce the initial displacement in order to achieve more leeway for 
backset. This would reduce benefits even more.
---------------------------------------------------------------------------

    \47\ ``Technical Analysis Relevant to Petitions for 
Reconsideration to the December 14, 2004 FMVSS 202a--Head Restraints 
Final Rule.''
---------------------------------------------------------------------------

    Given the potential loss in benefits, the agency denies this 
request.

C. Backset Retention and Displacement

1. Petition
    Kongsberg expressed its agreement with the petitions for 
reconsideration that recommended that the moment be returned to zero 
before reapplication of the reference load in the backset retention 
test. However, it questioned the correlation between the 102 mm limit 
on displacement of the head restraint beyond the displaced torso 
reference line during application of the 373 Nm moment. It petitioned 
the agency to set a lower value for displacement that would ``be 
correlated with a safety benefit.'' In addition, it disagreed with the 
13 mm displacement allowance after the moment returns to the reference 
load. It referred to this displacement as the ``permanent deformation'' 
of the head restraint. It recommended that the ``permanent 
deformation'' be measured from the initial position of the head 
restraint rather than the position achieved at the reference load. It 
referred to this measurement as ``effective backset retention'' and 
recommended a limit of 25 mm.
2. Agency Response
    We will begin by addressing the request to zero-out the applied 
moment during the testing. As discussed earlier in this document, the 
agency has agreed to make this change in response to petitions for 
reconsideration. Thus, the Kongsberg petition is moot on this point.
    In reference to the Kongsberg request to set a lesser value for the 
current 102

[[Page 25510]]

mm displacement limit beyond the displaced torso reference line, we 
make the following observations. This requirement was part of the 
standard when it originated in the late 1960s. In recent head restraint 
testing, even when the seat back was not braced, the average head 
restraint displacement was well below the required limit or close to 
actually being a negative displacement when using the displaced torso 
reference line as the zero displacement point.\48\ Thus, we acknowledge 
that, in this relatively small sample, the 102 mm limit is not driving 
head restraint design. However, the agency has no research to indicate 
how reducing the limit would affect head restraint performance. Nor has 
the petitioner suggested a value that would ``be correlated with a 
safety benefit.''
---------------------------------------------------------------------------

    \48\ ``Technical Analysis Relevant to Petitions for 
Reconsideration to the December 14, 2004 FMVSS 202a--Head Restraints 
Final Rule.''
---------------------------------------------------------------------------

    Finally, regarding the petitioner's disagreement with the 13 mm 
allowance in the backset retention test as well as its recommendation 
that the ``permanent deformation'' be measured from the unloaded head 
restraint position and that the limit be 25 mm, the petitioner appears 
to place great emphasis on the compliance of the head restraint, i.e., 
how flexible it is under initial load, in addition to how well it 
maintains its position after the load is removed. The focus of the 
backset retention test in the final rule is restricted to an assessment 
of the head restraint ability to remained locked in its position of 
adjustment. This is addressed with the 13 mm limit on the change in 
reference positions. This was not intended as a restriction on 
``permanent deformation.'' In addition, we did not intend to regulate 
the initial flexibility of the head restraint beyond the establishment 
of a 25 mm limit to assure there is no loophole for particularly weak 
locks.
    Based on agency testing, we believe that a head restraint whose 
lock maintains its integrity will pass the 25 mm initial reference load 
displacement and 13 mm reference position change limits separately.\49\ 
These same test data indicate that the average and standard deviation 
for backset retention displacement under the methodology recommended by 
Kongsberg is 26.1 mm 8.3 mm, when the seat back is not 
braced and the applied load is returned to zero. Thus, the average 
value is over the 25 mm limit recommended by the petitioner, and many 
head restraints would need to be redesigned if the recommendation was 
adopted.
---------------------------------------------------------------------------

    \49\ ``Technical Analysis Relevant to Petitions for 
Reconsideration to the December 14, 2004 FMVSS 202a--Head Restraints 
Final Rule.''
---------------------------------------------------------------------------

    Kongsberg has not provided any data as to the expected benefits 
that would accrue by measuring the backset retention from the initial 
head restraint position rather than from the reference load position. 
Absent this analysis, the agency denies this part of the petition.

D. Height Retention

1. Petition
    Kongsberg recommended that the agency adopt several changes to the 
height retention requirement. It expressed its agreement with petitions 
for reconsideration that recommended that the moment be returned to 
zero before reapplication of the reference load in the backset 
retention test. The height retention test is very similar to the 
backset retention test except that there is no limit on the head 
restraint displacement at peak load. The petitioner requested that the 
agency reevaluate the lack of a peak load limit and set a limit that 
provides safety benefit to taller occupants. The petitioner contends 
that the height retention requirement is not applied to non-adjustable 
head restraints and requested that it be expanded to all head 
restraints. Finally, it requested that the height retention limit be 
measured from the initial position rather than the reference position 
and that the limit be 25 mm instead of 13 mm. It called this an 
``effective height retention'' limit.
2. Agency Response
    First we will address the request to zero-out the applied moment 
during the testing. As discussed earlier in this document, the agency 
has agreed to make this change in response to petitions for 
reconsideration. Thus, the Kongsberg petition is moot on this issue.
    In reference to the Kongsberg request for setting a peak load 
displacement limit, we make the following observations. The agency has 
no research data nor are we aware of any data that would enable us to 
determine if a limit on head restraint displacement under the peak 
downward load of 500 N is appropriate or what the limit should be. In 
the absence of such data being provided by the petitioner, we decline 
to act in this area.
    In reference to the petitioner's recommendation concerning 
application of the height retention test to all head restraints, we 
wish to clarify that the current regulatory text does not exclude any 
head restraint design from the provisions of the height retention test.
    Finally, we address the request for an ``effective height 
retention'' limit. Based on agency testing, we believe that a head 
restraint whose lock maintains its integrity will pass the 25 mm 
initial reference load displacement and 13 mm reference position change 
limits separately.\50\ These same test data indicate that the average 
and standard deviation for height retention displacement under the 
methodology recommended by Kongsberg is 14.0 mm 3.2 mm, 
when the seat back is not braced and the applied load is returned to 
zero. Thus, we would expect most head restraints to meet the 25 mm 
limit recommended by the petitioner. Given these results, it is unclear 
what advantage would be achieved by changing the current requirement. 
Therefore the agency denies this part of the petition.
---------------------------------------------------------------------------

    \50\ ``Technical Analysis Relevant to Petitions for 
Reconsideration to the December 14, 2004 FMVSS 202a--Head Restraints 
Final Rule.''
---------------------------------------------------------------------------

E. Non-Use Position

1. Petition
    Kongsberg asked if the agency accepts the petitions for 
reconsideration of a 5 degree torso angle change option for non-use 
positions, that a warning label be required on the head restraint 
identifying the potential for neck injury and the need for a detailed 
explanation of the hazard in the owner's manual.
2. Agency Response
    As discussed earlier in this document, in response to petitions for 
reconsideration, the agency has reinstated (from the NPRM) a 10 degree 
torso angle change option for non-use positions. Our human factors 
study supported the need for the 10 degree torso angle change as 
opposed to the 5 degree change. In addition, the agency studied the 
effectiveness of warning labels on occupant behavior when paired with a 
5 degree torso angle change. The results showed that the label was 
highly ineffective. Thus, we rejected the idea of adding a label as 
part of the non-use position requirement. Therefore we are denying the 
Kongsberg rulemaking petition asking for a label on the head restraint 
in addition to a torso change requirement. For these reasons, we are 
denying the portion of the Kongsberg rulemaking petition asking for a 
label on the head restraint in addition to a torso change requirement.
    With respect to providing detailed explanations of neck injury 
hazards in the owner's manual; Kongsberg has not suggested what might 
be added to the December 2004 final rule requirements. We believe the 
current requirement is sufficient and have made minor changes

[[Page 25511]]

in response to petitions for reconsideration, explained in this 
document.

F. Definition of Rear Head Restraint

1. Petition
    FMVSS No. 202a defines a rear seat head restraint in the following 
way:
    ``[A]t any rear outboard designated seating position, a rear seat 
back, or any independently adjustable seat component attached to or 
adjacent to a seat back, that has a height equal to or greater than 700 
mm, in any position of backset and height adjustment, as measured in 
accordance with S5.1.1.''
    Kongsberg recommended that the agency modify the definition of a 
rear seat head restraint from one using a 700 mm height threshold to 
any head restraint that is an ``independently adjustable seat 
component.'' Kongsberg stated that ECE requires a minimum height of 750 
mm for any head restraint that is an ``independently adjustable seat 
component.'' It argued that the FMVSS No. 202a requirement should match 
that of the ECE since it has not seen any justification for why the 
public expectation in Europe should differ from that in North America.
2. Agency Response
    First, we will address Kongsberg's claim that the ECE requires a 
minimum height for an ``independently adjustable seat component.'' We 
are not aware of such a provision in ECE 17 relative to optionally 
provided rear seat head restraints.
    Second, the agency provided an extensive justification for our 
definition for rear seat head restraints in the preamble of the 2004 
final rule. Part of that justification was that the definition includes 
seats with cushion components on the top of the seat back, i.e., what 
the general public would consider a seat back. We also stated our 
belief that the definition had the required objectivity for an FMVSS.
    The petitioner has not provided any new information that would 
persuade the agency to change its position on this issue. Therefore, 
this part of the petition for rulemaking is denied.

G. Gaps

1. Petition
    Kongsberg requested that the agency modify the requirement for a 
maximum 60 mm gap between the fully down head restraint and seat back 
measured with a 165 mm sphere pressed against the seat back to a 25 mm 
gap measured by a 25 mm diameter sphere passed through the space 
between the seat back and head restraint. In addition, it requested 
that the agency limit the gap between the head restraint and seat back 
with the head restraint in the full up position.
2. Agency Response
    The agency received petitions for reconsideration on the issue of 
the maximum gap between the seat back and the fully down head 
restraint. Petitioners for reconsideration requested that this 
requirement be harmonized with the 25 mm gap in ECE 17. The petitioners 
indicated that the gap is to be measured perpendicular to the seat back 
angle. Our response to this petition for reconsideration is relevant 
here. Specifically, we modified the final rule to allow the use of 
either a 165 mm sphere pressed against the seat back with a 60 mm limit 
between the points of contact or a 25 mm diameter cylinder with its 
long axis perpendicular to the seat back angle and pushed into the gap 
between the head restraint and seat back.
    Kongsberg has requested the use of a 25 mm sphere rather than a 25 
mm cylinder. The agency has specified that a cylinder be used to be 
consistent with measuring the gap perpendicular to the seat back angle. 
Use of a sphere would be a less rigorous requirement since the gap 
could be oriented in any direction. Therefore, we are denying the 
rulemaking petition to use a 25 mm sphere to measure the gap.
    On the issue of restricting the gap between the head restraint in 
the fully up position and the seat back, the agency addressed this 
issue in the 2004 final rule preamble. The agency concluded at that 
time that such a requirement was unnecessary because most misadjusted 
head restraints are adjusted too low and that such a restriction might 
limit the maximum height of head restraints above the 800 mm 
requirement and reduce protection for taller occupants. The petitioner 
has not provided any new information that would persuade the agency to 
change its position on this issue. Therefore, this part of the petition 
for rulemaking is denied.

H. Removability of Head Restraints

1. Petition
    Kongsberg recommended that if the agency allowed a single input to 
adjust and remove the head restraint, the input effort must be mutually 
exclusive. For example, if a button is pressed to adjust down, that 
button must be pulled to remove the head restraint. Thus, Kongsberg 
would define ``distinct'' as ``mutually exclusive'' and under no 
circumstances could the same push-button be used for adjustment and 
removal. Referring to a petition for reconsideration the agency 
received on use of a single mechanism for downward adjustment and 
removal, Kongsberg stated that it does not believe the act to be 
distinct. It further stated that the agency must give consideration to 
the risk of injury when a head restraint is adjusted even slightly 
above the highest locking position.
2. Agency Response
    The agency received petitions for reconsideration on this issue. 
Our response to those petitions is relevant to Kongsberg petition for 
rulemaking. In response to petitions for reconsideration we decided to 
add the word ``upward'' to the restriction on removability such that it 
now states:
    ``The head restraint must not be removable without a deliberate 
action distinct from any act necessary for upward adjustment.''
    As discussed in this document, the revised requirement allows a 
push-button to release a head restraint for both downward adjustment 
and removal. This is a common design in many vehicles today. Although 
the push button action is the same for downward adjustment and removal, 
the actions are distinct because the head restraint is pushed down in 
one instance and pulled up in another. As indicated earlier in this 
document, the purpose of this provision is to prevent accidental 
removal of head restraints when being adjusted. This is a potential 
problem when the head restraint is being adjusted in an upward 
direction but not a downward direction.
    The petitioner's recommendation for the removability requirement 
would be more restrictive than the revised regulatory text. It would 
justify this more stringent requirement based on concerns about 
misadjustment above the highest locking position and potential 
resulting injuries. However, it is not clear to the agency how much 
more likely this type of misadjustment is under the Kongsberg's 
recommendation as opposed to the current definition. Absent any further 
information documenting the relative risks of the two approaches, the 
agency has decided to deny this part of the petition for rulemaking.

VIII. Rulemaking Analyses and Notices

A. Executive Order 12866 and DOT Regulatory Policies and Procedures

    NHTSA has considered the impacts of this rulemaking action under 
Executive Order 12866 and the Department of Transportation's regulatory 
policies and

[[Page 25512]]

procedures. This rulemaking document was not reviewed under E.O. 12866.
    This rule amends the agency's December 2004 final rule upgrading 
the agency's head restraint standard, which was considered significant 
because of public interest and economically significant because the 
agency estimated yearly economic cost savings of approximately $127 
million. However, as explained below, today's amendments are not 
significant.
    NHTSA is placing in the public docket a Supplemental Final 
Regulatory Evaluation describing the costs and benefits of this 
rulemaking action. Today's amendments will not affect the costs of the 
December 2004 final rule. However, as discussed in the SFRE and for the 
reasons discussed earlier in this document, the agency estimates that 
the change in seat back angle to provide greater flexibility with 
respect to backset will reduce front seat benefits by about 20 percent. 
We note that our estimate for rear seat benefits remains the same. This 
is because backset is not regulated for rear seat head restraints. In 
addition, our estimate of rear seat benefits is based on head restraint 
height. Although head restraint height is affected by seat back angle, 
since a large portion of rear seats are fixed or not adjustable, we are 
estimating no change in rear seat benefits.
    Table II shows the SFRE benefits estimates with respect to the 
benefits of the December 2004 final rule and how those benefits are 
changed by today's rule:

   Table II.--Benefits Comparison Between the Final Regulatory Impact
          Analysis and Supplemental Final Regulatory Evaluation
------------------------------------------------------------------------
           Whiplash injuries reduced                FRIA         SFRE
------------------------------------------------------------------------
Front Seat....................................       15,272       12,231
Rear Seat.....................................        1,559        1,559
                                               -------------------------
    Total.....................................       16,831       13,790
------------------------------------------------------------------------

B. Regulatory Flexibility Act

    NHTSA has considered the effects of this rulemaking action under 
the Regulatory Flexibility Act (5 U.S.C. 601 et seq.) The final rule 
will affect motor vehicle manufacturers, alterers, and seating 
manufacturers. NHTSA has determined that this action will not have a 
significant economic impact on a substantial number of small entities.
    In the preamble to the December 2004 final rule upgrading the head 
restraint standard, NHTSA made a determination that that rule will not 
have a significant economic impact on a substantial number of small 
entities. Today's amendments make relatively minor changes in that 
rule, generally for the purpose of providing greater flexibility. Since 
none of the amendments being made to the December 2004 final rule will 
significantly affect small entities, this rule will not have a 
significant economic impact on a substantial number of small entities.

C. National Environmental Policy Act

    NHTSA has analyzed the final rule for the purposes of the National 
Environmental Policy Act. The agency has determined that implementation 
of this action will not have any significant impact on the quality of 
the human environment.

D. Executive Order 13132 (Federalism)

    NHTSA has examined today's final rule pursuant to Executive Order 
13132 (64 FR 43255, August 10, 1999) and concluded that no additional 
consultation with States, local governments or their representatives is 
mandated beyond the rulemaking process. The agency has concluded that 
the rule does not have federalism implications because the rule does 
not have ``substantial direct effects on the States, on the 
relationship between the national government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government.''
    Further, no consultation is needed to discuss the preemptive effect 
of today's rule. NHTSA rules can have preemptive effect in at least two 
ways. First, the National Traffic and Motor Vehicle Safety Act contains 
an express preemptive provision: ``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.'' 49 U.S.C. 30103(b)(1). It is this statutory 
command that preempts State law, not today's rulemaking, so 
consultation would be inappropriate.
    In addition to the express preemption noted above, the Supreme 
Court has also recognized that State requirements imposed on motor 
vehicle manufacturers, including sanctions imposed by State tort law, 
can stand as an obstacle to the accomplishment and execution of a NHTSA 
safety standard. When such a conflict is discerned, the Supremacy 
Clause of the Constitution makes there State requirements 
unenforceable. See Geier v. American Honda Motor Co., 529 U.S. 861 
(2000). NHTSA has not outlined such potential State requirements in 
today's rulemaking, however, in part because such conflicts can arise 
in varied contexts, but it is conceivable that such a conflict may 
become clear through subsequent experience with today's standard and 
test regime. NHTSA may opine on such conflicts in the future, if 
warranted. See id. at 883-86.

E. Unfunded Mandates Reform Act

    Section 202 of the Unfunded Mandates Reform Act of 1995 (UMRA) 
requires Federal 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 in any one year ($120,700,000 as adjusted for 
inflation with base year of 1995).
    Because this final rule will not have a $100 million effect, no 
Unfunded Mandates assessment has been prepared. A full assessment of 
the rule's costs and benefits is provided in the SFRE.

F. Executive Order 12988 (Civil Justice Reform)

    With respect to the review of the promulgation of a new regulation, 
section 3(b) of Executive Order 12988, ``Civil Justice Reform'' (61 FR 
4729, February 7, 1996) requires that Executive agencies make every 
reasonable effort to ensure that the regulation: (1) Clearly specifies 
the preemptive effect; (2) clearly specifies the effect on existing 
Federal law or regulation; (3) provides a clear legal standard for 
affected conduct, while promoting simplification and burden reduction; 
(4) clearly specifies the retroactive effect, if any; (5) adequately 
defines key terms; and (7) addresses other important issues affecting 
clarity and general draftsmanship under any guidelines issued by the 
Attorney General. This document is consistent with that requirement.
    Pursuant to this Order, NHTSA notes as follows. The preemptive 
effect of this rule is discussed above. NHTSA notes further that there 
is no requirement that individuals submit a petition for 
reconsideration or pursue other administrative proceeding before they 
may file suit in court.

G. Paperwork Reduction Act

    The December 2004 final rule included the following ``collections 
of information,'' as that term is defined in 5 CFR Part 1320 
Controlling Paperwork

[[Page 25513]]

Burdens on the Public: the final rule required that vehicle 
manufacturers include in owners' manuals information about appropriate 
head restraint adjustment. Today's rule makes minor revisions to the 
owner's manual requirements. The revisions do not affect the nature of 
the information that must be provided or affect the burden hours. OMB 
has approved NHTSA's collection of owner's manual requirements under 
OMB clearance No. 2127-0541 Consolidated Justification of Owner's 
Manual Requirements for Motor Vehicles and Motor Vehicle Equipment. 
This clearance will expire on February 28, 2009. Given that the 
revisions will not affect the nature of the information that must be 
provided or the burden hours, the collection of information comes 
within that clearance.
    Two Years of Phase-in Reporting Requirements Beginning in 2010--
This final rule includes a phase-in period and reporting requirements 
for manufacturers of passenger cars, multipurpose passenger vehicles, 
trucks and buses with a GVWR of 4,536 kg or less, concerning the number 
of vehicles that meet requirements of Standard No. 202a. Two reports, 
one report for each of two consecutive years, will be required from 
each affected manufacturer. The reports will be due within 60 days 
after the end of the production year ending August 31, 2010, and within 
60 days after the end of the production year ending August 31, 2011. 
Although OMB approval for these collections of information will not be 
sought until late 2008 (as part of the request for renewal of OMB 
clearance No. 2127-0541), NHTSA describes the anticipated collection of 
information as follows:
    Type of Request--Revision of a Currently Approved Collection of 
Information.
    OMB Clearance No.--2127-0541.
    Form Number--This collection of information will not use any 
standard forms.
    Requested Expiration Date of Clearance--At present, Clearance No. 
2127-0541 is scheduled to expire on February 28, 2009. As a result of 
this final rule, NHTSA anticipates asking for another extension of this 
collection, though February 28, 2012.
    Summary of the Collection of Information--NHTSA will ask for an 
extension of approval to collect the information already approved under 
OMB Clearance No. 2127-0541. In addition, NHTSA will ask for approval 
to adopt phase-in reporting requirements similar to those used in other 
phase-ins. For each year of the phase-in period, manufacturers are 
required to provide to NHTSA, within 60 days after the August 31 end 
date of each ``production year,'' information identifying the vehicles 
(by make, model, and vehicle identification number (VIN)) that have 
been certified as complying with certain head restraint requirements.
    As discussed earlier, the implementation schedule for the new 
requirements is as follows:

--for the front seat requirements, 80 percent of each manufacturer's 
vehicles with a GVWR of 4,536 kg or less manufactured during the 
production year ending on August 31, 2010 (with the phase-in report due 
to NHTSA on October 31, 2010); and
--for the requirements for voluntarily installed rear head restraints, 
80 percent of each manufacturer's vehicles with rear head restraints, 
manufactured during the production year ending on August 31, 2011 (with 
the phase-in report due to NHTSA on October 31, 2011).

Description of the Need for the Information

    NHTSA needs this information to ensure that vehicle manufacturers 
are complying with the upgraded head restraint standard. NHTSA will use 
this information to determine whether a manufacturer has complied with 
the amended requirements of FMVSS No. 202a during the phase-in period.

Description of the Likely Respondents (Including Estimated Number, and 
Proposed Frequency of Response to the Collection of Information)

    NHTSA estimates that 26 vehicle manufacturers will submit the 
required information.

Estimate of the Total Annual Reporting and Recordkeeping Burden 
Resulting From this Collection of Information

    Anticipated Request for Clearance for February 28, 2009 through 
February 28, 2012--For each of 2010 and 2011, NHTSA anticipates 
requesting approval to collect an additional 26 hours per year to cover 
the phase-in reports from each of 26 manufacturers. Because NHTSA 
anticipates that the information will be collected and reported 100 
percent through electronic means, it does not anticipate each 
manufacturer taking more than an hour to compile the information.
    There would be 0 hours of recordkeeping burdens resulting from the 
collection of information.
    NHTSA estimates that there are no additional cost burdens resulting 
from this additional collection of information. There are no capital or 
start-up costs as a result of this collection.

H. Executive Order 13045

    Executive Order 13045 \51\ applies to any rule that: (1) Is 
determined to be ``economically significant'' as defined under E.O. 
12866, and (2) concerns an environmental, health or safety risk that 
NHTSA has reason to believe may have a disproportionate effect on 
children. If the regulatory action meets both criteria, we must 
evaluate the environmental health or safety effects of the planned rule 
on children, and explain why the planned regulation is preferable to 
other potentially effective and reasonably feasible alternatives 
considered by us. This rule is not economically significant, and it 
will not have a disproportionate effect on children.
---------------------------------------------------------------------------

    \51\ 62 FR 19885, April 23, 1997.
---------------------------------------------------------------------------

I. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act (NTTAA) requires NHTSA to evaluate and use existing voluntary 
consensus standards \52\ in its regulatory activities unless doing so 
would be inconsistent with applicable law (e.g., the statutory 
provisions regarding NHTSA's vehicle safety authority) or otherwise 
impractical. In meeting that requirement, we are required to consult 
with voluntary, private sector, consensus standards bodies. Examples of 
organizations generally regarded as voluntary consensus standards 
bodies include the American Society for Testing and Materials (ASTM), 
the Society of Automotive Engineers (SAE), and the American National 
Standards Institute (ANSI). If NHTSA does not use available and 
potentially applicable voluntary consensus standards, we are required 
by the Act to provide Congress, through OMB, an explanation of the 
reasons for not using such standards.
---------------------------------------------------------------------------

    \52\ Voluntary consensus standards are technical standards 
developed or adopted by voluntary consensus standards bodies. 
Technical standards are defined by the NHTSA as ``a performance-
based or design specific technical specifications and related 
management systems practices. They pertain to products and 
processes, such as size, strength, or technical performance of a 
product, process or material.''
---------------------------------------------------------------------------

    The agency is not aware of any new voluntary consensus standards 
addressing the changes made to the December 2004 final rule as a result 
of this final rule.

J. Privacy Act

    Anyone is able to search the electronic form of all comments 
received into any of our dockets by the

[[Page 25514]]

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 (65 FR 19477 at 19478).

List of Subjects in 49 CFR Parts 571 and 585

    Imports, Incorporation by Reference, Motor Vehicle Safety, Motor 
Vehicles, Reporting and recordkeeping requirements, and Tires.


0
In consideration of the foregoing, 49 CFR parts 571 and 585 are amended 
as follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

0
1. The authority citation for part 571 of title 49 continues to read as 
follows:

    Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166; 
delegation of authority at 49 CFR 1.50.


0
2. Section 571.202 is amended by revising the section heading, S2, S4, 
and S4.1 to read as follows:


571.202  Standard No. 202; Head restraints; Applicable at the 
manufacturers option until September 1, 2009.

* * * * *
    S2. Application. This standard applies to passenger cars, and to 
multipurpose passenger vehicles, trucks and buses with a GVWR of 4,536 
kg or less, manufactured before September 1, 2009. Until September 1, 
2009, manufacturers may comply with the standard in this Sec.  571.202, 
with the European regulations referenced in S4.3 of this Sec.  571.202, 
or with the standard in Sec.  571.202a. For vehicles manufactured on or 
after September 1, 2009 and before September 1, 2010, manufacturers may 
comply with the standard in this Sec.  571.202 or with the European 
regulations referenced in S4.3 of this Sec.  571.202, instead of the 
standard in Sec.  571.202a, only to the extent consistent with phase-in 
specified in Sec.  571.202a.
* * * * *
    S4. Requirements.
    S4.1 Each passenger car, and multipurpose passenger vehicle, truck 
and bus with a GVWR of 4,536 kg or less, must comply with, at the 
manufacturer's option, S4.2, S4.4 or S4.5 of this section.
* * * * *

0
3. Section 571.202a is revised to read as follows:


Sec.  571.202a  Standard No. 202a; Head restraints; Mandatory 
applicability begins on September 1, 2009.

    S1. Purpose and scope. This standard specifies requirements for 
head restraints to reduce the frequency and severity of neck injury in 
rear-end and other collisions.
    S2. Application & incorporation by reference.
    S2.1 Application. This standard applies to passenger cars, and to 
multipurpose passenger vehicles, trucks and buses with a GVWR of 4,536 
kg or less, manufactured on or after September 1, 2009. However, the 
standard's requirements for rear head restraints do not apply to 
vehicles manufactured before September 1, 2010, and, for vehicles 
manufactured between September 1, 2010 and August 31, 2011, the 
requirements for rear head restraints apply only to the extent provided 
in S7. Until September 1, 2009, manufacturers may comply with the 
standard in this Sec.  571.202a, with the standard in Sec.  571.202, or 
with the European regulations referenced in S4.3(a) of Sec.  571.202. 
For vehicles manufactured on or after September 1, 2009 and before 
September 1, 2010, manufacturers may comply with the standard in Sec.  
571.202 or with the European regulations referenced in S4.3(a) of Sec.  
571.202, instead of the standard in this Sec.  571.202a, only to the 
extent consistent with the phase-in specified in this Sec.  571.202a.
    S2.2 Incorporation by reference.
    (a) Society of Automotive Engineers (SAE) Recommended Practice 
J211/1 rev. Mar 95, ``Instrumentation for Impact Test--Part 1--
Electronic Instrumentation,'' SAE J211/1 (rev. Mar 95) is incorporated 
by reference in S5.2.5(b), S5.3.8, S5.3.9, and 5.3.10 of this section. 
The Director of the Federal Register has approved the incorporation by 
reference of this material in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. A copy of SAE J211/1 (rev. Mar 95) may be obtained from SAE at 
the Society of Automotive Engineers, Inc., 400 Commonwealth Drive, 
Warrendale, PA 15096. A copy of SAE J211/1 (rev. Mar 95) may be 
inspected at NHTSA's Technical Information Services, 400 Seventh 
Street, SW., Plaza Level, Room 403, Washington, DC, or at the National 
Archives and Records Administration (NARA). For information on the 
availability of this material at NARA, call 202-741-6030, or go to: 
http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
    (b) Society of Automotive Engineers (SAE) Standard J826 ``Devices 
for Use in Defining and Measuring Vehicle Seating Accommodation,'' SAE 
J826 (rev. Jul 95) is incorporated by reference in S3, S5, S5.1, 
S5.1.1, S5.2, S5.2.1, S5.2.2, and S5.2.7 of this section. The Director 
of the Federal Register has approved the incorporation by reference of 
this material in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. A 
copy of SAE J826 (rev. Jul 95) may be obtained from SAE at the Society 
of Automotive Engineers, Inc., 400 Commonwealth Drive, Warrendale, PA 
15096. A copy of SAE J826 (rev. Jul 95) may be inspected at NHTSA's 
Technical Information Services, 400 Seventh Street, SW., Plaza Level, 
Room 403, Washington, DC or at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
    S3. Definitions.
    Backset means the minimum horizontal distance between the rear of a 
representation of the head of a seated 50th percentile male occupant 
and the head restraint, as measured by the head restraint measurement 
device.
    Head restraint means a device that limits rearward displacement of 
a seated occupant's head relative to the occupant's torso.
    Head restraint measurement device (HRMD) means the Society of 
Automotive Engineers (SAE) (July 1995) J826 three-dimensional manikin 
with a head form attached, representing the head position of a seated 
50th percentile male, with sliding scale at the back of the head for 
the purpose of measuring backset. The head form is designed by and 
available from the ICBC, 151 West Esplanade, North Vancouver, BC V7M 
3H9, Canada (www.icbc.com).
    Height means, when used in reference to a head restraint, the 
distance from the H-point, measured parallel to the torso reference 
line defined by the three dimensional SAE J826 (July 1995) manikin, to 
a plane normal to the torso reference line.
    Intended for occupant use means, when used in reference to the 
adjustment of a seat, positions other than that intended solely for the 
purpose of allowing ease of ingress and egress of occupants and access 
to cargo storage areas of a vehicle.
    Rear head restraint means, at any rear outboard designated seating 
position, a rear seat back, or any independently adjustable seat 
component attached to or adjacent to a seat back, that has a height 
equal to or greater than 700 mm, in any position of backset and height

[[Page 25515]]

adjustment, as measured in accordance with S5.1.1.
    Top of the head restraint means the point on the head restraint 
with the greatest height.
    S4. Requirements. Except as provided in S4.4, S4.2.1(a)(2) and 
S4.2.1(b)(2) of this section, each vehicle must comply with S4.1 of 
this section with the seat adjusted as intended for occupant use. 
Whenever a range of measurements is specified, the head restraint must 
meet the requirement at any position of adjustment within the specified 
range.
    S4.1 Performance levels. In each vehicle other than a school bus, a 
head restraint that conforms to either S4.2 or S4.3 of this section 
must be provided at each front outboard designated seating position. In 
each equipped with rear outboard head restraints, the rear head 
restraint must conform to either S4.2 or S4.3 of this section. In each 
school bus, a head restraint that conforms to either S4.2 or S4.3 of 
this section must be provided for the driver's seating position. At 
each designated seating position incapable of seating a 50th percentile 
male Hybrid III test dummy specified in 49 CFR Part 572, Subpart E, the 
applicable head restraint must conform to S4.2 of this section.
    S4.2 Dimensional and static performance. Each head restraint 
located in the front outboard designated seating position and each head 
restraint located in the rear outboard designated seating position must 
conform to paragraphs S4.2.1 through S4.2.7 of this section. Compliance 
is determined for the height requirements of S4.2.1 and the backset 
requirements of S4.2.3 of this section by taking the arithmetic average 
of three measurements.
    S4.2.1 Minimum height.
    (a) Front outboard designated seating positions. (1) Except as 
provided in S4.2.1(a)(2) of this section, when measured in accordance 
with S5.2.1(a)(1) of this section, the top of a head restraint located 
in a front outboard designated seating position must have a height not 
less than 800 mm in at least one position of adjustment.
    (2) Exception. The requirements of S4.2.1(a)(1) do not apply if the 
interior surface of the vehicle at the roofline physically prevents a 
head restraint, located in the front outboard designated seating 
position, from attaining the required height. In those instances in 
which this head restraint cannot attain the required height, when 
measured in accordance with S5.2.1(a)(2), the maximum vertical distance 
between the top of the head restraint and the interior surface of the 
vehicle at the roofline must not exceed 50 mm for convertibles and 25 
mm for all other vehicles. Notwithstanding this exception, when 
measured in accordance with S5.2.1(a)(2), the top of a head restraint 
located in a front outboard designated seating position must have a 
height not less than 700 mm in the lowest position of adjustment.
    (b) All outboard designated seating positions equipped with head 
restraints.
    (1) Except as provided in S4.2.1(b)(2) of this section, when 
measured in accordance with S5.2.1(b)(1) of this section, the top of a 
head restraint located in an outboard designated seating position must 
have a height not less than 750 mm in any position of adjustment.
    (2) Exception. The requirements of S4.2.1(b)(1) do not apply if the 
interior surface of the vehicle at the roofline or the interior surface 
of the backlight physically prevent a head restraint, located in the 
rear outboard designated seating position, from attaining the required 
height. In those instances in which this head restraint cannot attain 
the required height, when measured in accordance with S5.2.1(b)(2), the 
maximum vertical distance between the top of the head restraint and the 
interior surface of the vehicle at the roofline or the interior surface 
of the backlight must not exceed 50 mm for convertibles and 25 mm for 
all other vehicles.
    S4.2.2 Width. When measured in accordance with S5.2.2 of this 
section, 65  3 mm below the top of the head restraint, the 
lateral width of a head restraint must be not less than 170 mm, except 
the lateral width of the head restraint for front outboard designated 
seating positions in a vehicle with a front center designated seating 
position, must be not less than 254 mm.
    S4.2.3 Front Outboard Designated Seating Position Backset. When 
measured in accordance with S5.2.3 of this section, the backset must 
not be more than 55 mm, when the seat is adjusted in accordance with 
S5.1. For adjustable restraints, the requirements of this section must 
be met with the top of the head restraint in any height position of 
adjustment between 750 mm and 800 mm, inclusive. If the top of the head 
restraint, in its lowest position of adjustment, is above 800 mm, the 
requirements of this section must be met at that position. If the head 
restraint position is independent of the seat back inclination 
position, the head restraint must not be adjusted such that backset is 
more than 55 mm when the seat back inclination is positioned closer to 
vertical than the position specified in S5.1.
    S4.2.4 Gaps.
    All head restraints must meet limits for gaps in the head restraint 
specified in S4.2.4.1. For gaps between the seat and head restraint, 
adjustable head restraints must meet either the limits specified in 
S4.2.4.1 or S4.2.4.2.
    S4.2.4.1 Gaps within the head restraint and between the head 
restraint and seat using a 165 mm sphere. When measured in accordance 
with S5.2.4.1 of this section using the head form specified in that 
paragraph, there must not be any gap greater than 60 mm within or 
between the anterior surface of the head restraint and anterior surface 
of the seat, with the head restraint adjusted to its lowest height 
position and any backset position, except as allowed by S4.4.
    S4.2.4.2 Gaps between the adjustable head restraint and seat using 
a 25 mm cylinder. When measured in accordance with S5.2.4.2 of this 
section using the 25 mm cylinder specified in that paragraph, there 
must not be any gap greater than 25 mm between the anterior surface of 
the head restraint and anterior surface of the seat, with the head 
restraint adjusted to its lowest height position and any backset 
position, except as allowed by S4.4.
    S4.2.5 Energy absorption. When the anterior surface of the head 
restraint is impacted in accordance with S5.2.5 of this section by the 
head form specified in that paragraph at any velocity up to and 
including 24.1 km/h, the deceleration of the head form must not exceed 
785 m/s\2\ (80 g) continuously for more than 3 milliseconds.
    S4.2.6 Height retention. When tested in accordance with S5.2.6 of 
this section, the cylindrical test device specified in S5.2.6(b) must 
return to within 13 mm of its initial reference position after 
application of at least a 500 N load and subsequent reduction of the 
load to 50 N  1 N. During application of the initial 50 N 
reference load, as specified in S5.2.6(b)(2) of this section, the 
cylindrical test device must not move downward more than 25 mm.
    S4.2.7 Backset retention, displacement, and strength.
    (a) Backset retention and displacement. When tested in accordance 
with S5.2.7 of this section, the described head form must:
    (1) Not be displaced more than 25 mm during the application of the 
initial reference moment of 37  0.7 Nm;
    (2) Not be displaced more than 102 mm perpendicularly and posterior 
of the displaced extended torso reference line during the application 
of a 373  7.5 Nm moment about the H-point; and
    (3) Return to within 13 mm of its initial reference position after 
the application of a 373  7.5 Nm moment

[[Page 25516]]

about the H-point and reduction of the moment to 37  0.7 
Nm.
    (b) Strength. When the head restraint is tested in accordance with 
S5.2.7(b) of this section with the test device specified in that 
paragraph, the load applied to the head restraint must reach 890 N and 
remain at 890 N for a period of 5 seconds.
    S4.3 Dynamic performance and width. At each forward-facing outboard 
designated seating position equipped with a head restraint, the head 
restraint adjusted midway between the lowest and the highest position 
of adjustment must conform to the following:
    S4.3.1 Injury criteria. When tested in accordance with S5.3 of this 
section, during a forward acceleration of the dynamic test platform 
described in S5.3.1, the head restraint must:
    (a) Angular rotation. Limit posterior angular rotation between the 
head and torso of the 50th percentile male Hybrid III test dummy 
specified in 49 CFR part 572, subpart E, fitted with sensors to measure 
rotation between the head and torso, to 12 degrees for the dummy in all 
outboard designated seating positions;
    (b) Head injury criteria. Limit the maximum HIC15 value 
to 500. HIC15 is calculated as follows--
    For any two points in time, t1 and t2, during 
the event which are separated by not more than a 15 millisecond time 
interval and where t1 is less than t2, the head 
injury criterion (HIC15) is determined using the resultant 
head acceleration at the center of gravity of the dummy head, a 
r, expressed as a multiple of g (the acceleration of 
gravity) and is calculated using the expression:
[GRAPHIC] [TIFF OMITTED] TR04MY07.164

    4.3.2 Width. The head restraint must have the lateral width 
specified in S4.2.2 of this section.
    S4.4 Folding or retracting rear head restraints non-use positions. 
A rear head restraint may be adjusted to a position at which its height 
does not comply with the requirements of S4.2.1 of this section. 
However, in any such position, the head restraint must meet either 
S4.4(a), (b) or (c) of this section.
    (a) The head restraint must automatically return to a position in 
which its minimum height is not less than that specified in S4.2.1(b) 
of this section when a test dummy representing a 5th percentile female 
Hybrid III test dummy specified in 49 CFR part 572, subpart O is 
positioned according to S5.4(a); or
    (b) The head restraint must, when tested in accordance with S5.4(b) 
of this section, be capable of manually rotating forward or rearward by 
not less than 60 degrees from any position of adjustment in which its 
minimum height is not less than that specified in S4.2.1(b) of this 
section.
    (c) The head restraint must, when tested in accordance with S5.4(b) 
of this section, cause the torso reference line angle to be at least 10 
degrees closer to vertical than when the head restraint is in any 
position of adjustment in which its height is not less than that 
specified in S4.2.1(b)(1) of this section.
    S4.5 Removability of head restraints. The head restraint must not 
be removable without a deliberate action distinct from any act 
necessary for upward adjustment.
    S4.6 Compliance option selection. Where manufacturer options are 
specified in this section, the manufacturer must select an option by 
the time it certifies the vehicle and may not thereafter select a 
different option for that vehicle. The manufacturer may select 
different compliance options for different designated seating positions 
to which the requirements of this section are applicable. Each 
manufacturer must, upon request from the National Highway Traffic 
Safety Administration, provide information regarding which of the 
compliance options it has selected for a particular vehicle or make/
model.
    S4.7 Information in owner's manual.
    S4.7.1 The owner's manual for each vehicle must emphasize that all 
occupants, including the driver, should not operate a vehicle or sit in 
a vehicle's seat until the head restraints are placed in their proper 
positions in order to minimize the risk of neck injury in the event of 
a crash.
    S4.7.2 The owner's manual for each vehicle must--
    (a) Include an accurate description of the vehicle's head restraint 
system in an easily understandable format. The owner's manual must 
clearly identify which seats are equipped with head restraints;
    (b) If the head restraints are removable, the owner's manual must 
provide instructions on how to remove the head restraint by a 
deliberate action distinct from any act necessary for upward 
adjustment, and how to reinstall head restraints;
    (c) Warn that all head restraints must be reinstalled to properly 
protect vehicle occupants.
    (d) Describe in an easily understandable format the adjustment of 
the head restraints and/or seat back to achieve appropriate head 
restraint position relative to the occupant's head. This discussion 
must include, at a minimum, accurate information on the following 
topics:
    (1) A presentation and explanation of the main components of the 
vehicle's head restraints.
    (2) The basic requirements for proper head restraint operation, 
including an explanation of the actions that may affect the proper 
functioning of the head restraints.
    (3) The basic requirements for proper positioning of a head 
restraint in relation to an occupant's head position, including 
information regarding the proper positioning of the center of gravity 
of an occupant's head or some other anatomical landmark in relation to 
the head restraint.
    S5. Procedures. Demonstrate compliance with S4.2 through S4.4 of 
this section with any adjustable lumbar support adjusted to its most 
posterior nominal design position. If the seat cushion adjusts 
independently of the seat back, position the seat cushion such that the 
highest H-point position is achieved with respect to the seat back, as 
measured by SAE J826 (July 1995) manikin, with leg length specified in 
S10.4.2.1 of Sec.  571.208 of this Part. If the specified position of 
the H-point can be achieved with a range of seat cushion inclination 
angles, adjust the seat inclination such that the most forward part of 
the seat cushion is at its lowest position with respect to the most 
rearward part. All tests specified by this standard are conducted with 
the ambient temperature between 18 degrees C. and 28 degrees C.
    S5.1 Except as specified in S5.2.3 and S5.3 of this section, if the 
seat back is adjustable, it is set at an initial inclination position 
closest to the manufacturer's design seat back angle, as measured by 
SAE J826 manikin. If there is more than one inclination position 
closest to the design angle, set the seat back inclination to the 
position closest to and rearward of the design angle.
    S5.1.1 Procedure for determining presence of head restraints in 
rear outboard seats. Measure the height of the top of a rear seat back 
or the top of any independently adjustable seat component attached to 
or adjacent to the rear seat back in its highest position of adjustment 
using the scale incorporated into the SAE J826 (July 1995) manikin or 
an equivalent scale, which is positioned laterally within 15 mm of the 
centerline of the rear seat back or any independently adjustable seat 
component attached to or adjacent to the rear seat back.
    S5.2 Dimensional and static performance procedures. Demonstrate

[[Page 25517]]

compliance with S4.2 of this section in accordance with S5.2.1 through 
S5.2.7 of this section. Position the SAE J826 (July 1995) manikin 
according to the seating procedure found in SAE J826 (July 1995).
    S5.2.1 Procedure for height measurement. Demonstrate compliance 
with S4.2.1 of this section in accordance with S5.2.1 (a) and (b) of 
this section, using the headroom probe scale incorporated into the SAE 
J826 (July 1995) manikin with the appropriate offset for the H-point 
position or an equivalent scale, which is positioned laterally within 
15 mm of the head restraint centerline. If the head restraint position 
is independent of the seat back inclination position, compliance is 
determined at a seat back inclination position closest to the design 
seat back angle, and each seat back inclination position less than the 
design seat back angle.
    (a)(1) For head restraints in front outboard designated seating 
positions, adjust the top of the head restraint to the highest position 
and measure the height.
    (2) For head restraints located in the front outboard designated 
seating positions that are prevented by the interior surface of the 
vehicle at the roofline from meeting the required height as specified 
in S4.2.1(a)(1), measure the clearance between the top of the head 
restraint and the interior surface of the vehicle at the roofline, with 
the seat adjusted to its lowest vertical position intended for occupant 
use, by attempting to pass a 25 mm sphere between them. Adjust the top 
of the head restraint to the lowest position and measure the height.
    (b)(1) For head restraints in all outboard designated seating 
positions equipped with head restraints, adjust the top of the head 
restraint to the lowest position other than allowed by S4.4 and measure 
the height.
    (2) For head restraints located in rear outboard designated seating 
positions that are prevented by the interior surface of the vehicle at 
the roofline or the interior surface of the rear backlight from meeting 
the required height as specified in S4.2.1(b)(1), measure the clearance 
between the top of the head restraint or the seat back and the interior 
surface of the vehicle at the roofline or the interior surface of the 
rear backlight, with the seat adjusted to its lowest vertical position 
intended for occupant use, by attempting to pass a 25 mm sphere between 
them.
    S5.2.2 Procedure for width measurement. Demonstrate compliance with 
S4.2.2 of this section using calipers to measure the maximum dimension 
perpendicular to the vehicle vertical longitudinal plane of the 
intersection of the head restraint with a plane that is normal to the 
torso reference line of SAE J826 (July 1995) manikin and 65  3 mm below the top of the head restraint.
    S5.2.3 Procedure for backset measurement. Demonstrate compliance 
with S4.2.3 of this section using the HRMD positioned laterally within 
15 mm of the head restraint centerline. Adjust the front head restraint 
so that its top is at any height between and inclusive of 750 mm and 
800 mm and its backset is in the maximum position other than allowed by 
S4.4. If the lowest position of adjustment is above 800 mm, adjust the 
head restraint to that position. If the head restraint position is 
independent of the seat back inclination position, compliance is 
determined at each seat back inclination position closest to and less 
than the design seat back angle.
    S5.2.4 Procedures for gap measurement.
    S5.2.4.1 Procedure using a 165 mm sphere.
    Demonstrate compliance with S4.2.4.1 of this section in accordance 
with the procedures of S5.2.4.1 (a) through (c) of this section, with 
the head restraint adjusted to its lowest height position and any 
backset position, except as allowed by S4.4.
    (a) The area of measurement is anywhere on the anterior surface of 
the head restraint or seat with a height greater than 540 mm and within 
the following distances from the centerline of the seat--
    (1) 127 mm for seats required to have 254 mm minimum head restraint 
width; and
    (2) 85 mm for seats required to have a 170 mm head restraint width.
    (b) Applying a load of no more than 5 N against the area of 
measurement specified in subparagraph (a), place a 165  2 
mm diameter spherical head form against any gap such that at least two 
points of contact are made within the area. The surface roughness of 
the head form is less than 1.6 [mu]m, root mean square.
    (c) Determine the gap dimension by measuring the vertical straight 
line distance between the inner edges of the two furthest contact 
points, as shown in Figures 2, 3 and 4.
    S5.2.4.2 Procedure using a 25 mm cylinder.
    Demonstrate compliance with S4.2.4.2 of this section in accordance 
with the procedures of S5.2.4.2 (a) through (c) of this section, with 
the head restraint adjusted to its lowest height position and any 
backset position, except as allowed by S4.4.
    (a) The area of measurement is between the anterior surface of the 
head restraint and seat with a height greater than 540 mm and within 
the following distances from the centerline of the seat--
    (1) 127 mm for seats required to have 254 mm minimum head restraint 
width; and
    (2) 85 mm for seats required to have a 170 mm head restraint width.
    (b) Orient a 25  1 mm diameter cylinder such that its 
long axis is perpendicular to the seat back angle and in a vertical 
longitudinal vehicle plane. Applying a load of no more than 5 N along 
the axis of the cylinder, place the cylinder against any gap within the 
area of measurement specified in subparagraph (a). The surface 
roughness of the cylinder is less than 1.6 [mu]m, root mean square.
    (c) Determine if at least 125 mm of the cylinder can completely 
pass through the gap.
    S5.2.5 Procedures for energy absorption. Demonstrate compliance 
with S4.2.5 of this section in accordance with S5.2.5 (a) through (e) 
of this section, with adjustable head restraints in any height and 
backset position of adjustment.
    (a) Use an impactor with a semispherical head form with a 165 
 2 mm diameter and a surface roughness of less than 1.6 
[mu]m, root mean square. The head form and associated base have a 
combined mass of 6.8  0.05 kg.
    (b) Instrument the impactor with an acceleration sensing device 
whose output is recorded in a data channel that conforms to the 
requirements for a 600 Hz channel class as specified in SAE Recommended 
Practice J211/1 (March 1995). The axis of the acceleration-sensing 
device coincides with the geometric center of the head form and the 
direction of impact.
    (c) Propel the impactor toward the head restraint. At the time of 
launch, the longitudinal axis of the impactor is within 2 degrees of 
being horizontal and parallel to the vehicle longitudinal axis. The 
direction of travel is posteriorly.
    (d) Constrain the movement of the head form so that it travels 
linearly along the path described in S5.2.5(c) of this section for not 
less than 25 mm before making contact with the head restraint.
    (e) Impact the anterior surface of the seat or head restraint at 
any point with a height greater than 635 mm and within a distance of 
the head restraint vertical centerline of 70 mm.
    S5.2.6 Procedures for height retention. Demonstrate compliance with 
S4.2.6 of this section in accordance with S5.2.6(a) through (e) of this 
section. For

[[Page 25518]]

head restraints that move with respect to the seat when occupant 
loading is applied to the seat back, S5.2.6(a) through (e) may be 
performed with the head restraint fixed in a position corresponding to 
the position when the seat is unoccupied.
    (a) Adjust the adjustable head restraint so that its top is at any 
of the following height positions at any backset position--
    (1) For front outboard designated seating positions--
    (i) The highest position; and
    (ii) Not less than, but closest to 800 mm; and
    (2) For rear outboard designated seating positions equipped with 
head restraints--
    (i) The highest position; and
    (ii) Not less than, but closest to 750 mm.
    (b)(1) Orient a cylindrical test device having a 165  2 
mm diameter in plan view (perpendicular to the axis of revolution), and 
a 152 mm length in profile (through the axis of revolution) with a 
surface roughness of less than 1.6 [mu]m, root mean square, such that 
the axis of the revolution is horizontal and in the longitudinal 
vertical plane through the longitudinal centerline of the head 
restraint. Position the midpoint of the bottom surface of the cylinder 
in contact with the head restraint.
    (2) Establish initial reference position by applying a vertical 
downward load of 50  1 N at the rate of 250  50 
N/minute. Determine the reference position after 5.5  0.5 
seconds at this load.
    (c) Increase the load at the rate of 250  50 N/minute 
to at least 500 N and maintain this load for 5.5  0.5 
seconds.
    (d) Reduce the load at the rate of 250  50 N/minute 
until the load is completely removed. Maintain this condition for not 
more than two minutes.
    (e) Increase the load at the rate of 250  50 N/minute 
to 50  1 N and, after 5.5  0.5 seconds at this 
load, determine the position of the cylindrical device with respect to 
its initial reference position.
    S5.2.7 Procedures for backset retention, displacement, and 
strength. Demonstrate compliance with S4.2.7 of this section in 
accordance with S5.2.7(a) and (b) of this section. The load vectors 
that generate moment on the head restraint are initially contained in a 
vertical plane parallel to the vehicle longitudinal centerline.
    (a) Backset retention and displacement. For head restraints that 
move with respect to the seat when occupant loading is applied to the 
seat back, S5.2.7(a)(1) through (8) may be performed with the head 
restraint fixed in a position corresponding to the position when the 
seat is unoccupied.
    (1) Adjust the head restraint so that its top is at a height 
closest to and not less than:
    (i) 800 mm for front outboard designated seating positions (or the 
highest position of adjustment for head restraints subject to 
S4.2.1(a)(2)); and
    (ii) 750 mm for rear outboard designated seating positions equipped 
with head restraints (or the highest position of adjustment for rear 
head restraints subject to S4.2.1(b)(2)).
    (2) Adjust the head restraint to any backset position.
    (3) In the seat, place a test device having the back pan dimensions 
and torso reference line (vertical center line), when viewed laterally, 
with the head room probe in the full back position, of the three 
dimensional SAE J826 (July 1995) manikin;
    (4) Establish the displaced torso reference line by creating a 
posterior moment of 373  7.5 Nm about the H-point by 
applying a force to the seat back through the back pan at the rate of 
187  37 Nm/minute. The initial location on the back pan of 
the moment generating force vector has a height of 290 mm  
13 mm. Apply the force vector normal to the torso reference line and 
maintain it within 2 degrees of a vertical plane parallel to the 
vehicle longitudinal centerline. Constrain the back pan to rotate about 
the H-point. Rotate the force vector direction with the back pan.
    (5) Maintain the position of the back pan as established in 
S5.2.7(a)(4) of this section. Using a 165  2 mm diameter 
spherical head form with a surface roughness of less than 1.6 [mu]m, 
root mean square, establish the head form initial reference position by 
applying, perpendicular to the displaced torso reference line, a 
posterior initial load at the seat centerline at a height 65  3 mm below the top of the head restraint that will produce a 37 
 0.7 Nm moment about the H-point. After maintaining this 
moment for 5.5  0.5 seconds, measure the posterior 
displacement of the head form during the application of the load.
    (6) Increase the initial load at the rate of 187  37 
Nm/minute until a 373  7.5 Nm moment about the H-point is 
produced. Maintain the load level producing that moment for 5.5  0.5 seconds and then measure the posterior displacement of the 
head form relative to the displaced torso reference line.
    (7) Reduce the load at the rate of 187  37 Nm/minute 
until it is completely removed. Maintain this condition for not more 
than two minutes.
    (8) Increase the load at the rate of 187  37 Nm/minute 
until a 37  0.7 Nm moment about the H-point is produced. 
After maintaining the load level producing that moment for 5.5  0.5 seconds, measure the posterior displacement of the head form 
position with respect to its initial reference position; and
    (b) Strength. Increase the load specified in S5.2.7(a)(7) of this 
section at the rate of 250  50 N/minute to at least 890 N 
and maintain this load level for 5.5  0.5 seconds.
    S5.3 Procedures for dynamic performance. Demonstrate compliance 
with S4.3 of this section in accordance with S5.3.1 though S5.3.9 of 
this section with a 50th percentile male Hybrid III test dummy 
specified in 49 CFR Part 572 Subpart E, fitted with sensors to measure 
head to torso rotation. The dummy with all sensors is to continue to 
meet all specifications in 49 CFR Part 572 Subpart E. The restraint is 
positioned midway between the lowest and the highest position of 
adjustment.
    S5.3.1 Mount the vehicle on a dynamic test platform at the vehicle 
altitude set forth in S13.3 of Sec.  571.208 of this part, so that the 
longitudinal centerline of the vehicle is parallel to the direction of 
the test platform travel and so that movement between the base of the 
vehicle and the test platform is prevented. Instrument the platform 
with an accelerometer and data processing system. Position the 
accelerometer sensitive axis parallel to the direction of test platform 
travel.
    S5.3.2 Remove the tires, wheels, fluids, and all unsecured 
components. Remove or rigidly secure the engine, transmission, axles, 
exhaust, vehicle frame and any other vehicle component necessary to 
assure that all points on the acceleration vs. time plot measured by an 
accelerometer on the dynamic test platform fall within the corridor 
described in Figure 1 and Table 1.
    S5.3.3 Place any moveable windows in the fully open position.
    S5.3.4 Seat Adjustment. At each outboard designated seating 
position, if the seat back is adjustable, it is set at an initial 
inclination position closest to 25 degrees from the vertical, as 
measured by SAE J826 (July 1995) manikin. If there is more than one 
inclination position closest to 25 degrees from the vertical, set the 
seat back inclination to the position closest to and rearward of 25 
degrees. Using any control that primarily moves the entire seat 
vertically, place the seat in the lowest position. Using any control 
that primarily moves the entire seat in the fore and aft directions, 
place the seat midway between the forwardmost and

[[Page 25519]]

rearmost position. If an adjustment position does not exist midway 
between the forwardmost and rearmost positions, the closest adjustment 
position to the rear of the midpoint is used. Adjust the seat cushion 
and seat back as required by S5 and S5.1 of this section. If the head 
restraint is adjustable, adjust the top of the head restraint to a 
position midway between the lowest position of adjustment and the 
highest position of adjustment. If an adjustment position midway 
between the lowest and the highest position does not exist, adjust the 
head restraint to a position below and nearest to midway between the 
lowest position of adjustment and the highest position of adjustment.
    S5.3.5 Seat Belt Adjustment. Prior to placing the Type 2 seat belt 
around the test dummy, fully extend the webbing from the seat belt 
retractor(s) and release it three times to remove slack. If an 
adjustable seat belt D-ring anchorage exists, place it in the 
adjustment position closest to the mid-position. If an adjustment 
position does not exist midway between the highest and lowest position, 
the closest adjustment position above the midpoint is used.
    S5.3.6 Dress and adjust each test dummy as specified in S8.1.8.2 
through S8.1.8.3 of Sec.  571.208 of this Part. The stabilized test 
temperature of the test dummy is at any temperature level between 69 
degrees F and 72 degrees F, inclusive.
    S5.3.7 Test dummy positioning procedure. Place a test dummy at each 
outboard designated seating position equipped with a head restraint.
    S5.3.7.1 Head. The transverse instrumentation platform of the head 
is level within \1/2\ degree. To level the head of the test dummy, the 
following sequence is followed. First, adjust the position of the H-
point within the limits set forth in S10.4.2.1 of Sec.  571.208 to 
level the transverse instrumentation platform of the head of the test 
dummy. If the transverse instrumentation platform of the head is still 
not level, then adjust the pelvic angle of the test dummy. If the 
transverse instrumentation platform of the head is still not level, 
then adjust the neck bracket of the dummy the minimum amount necessary 
from the non-adjusted ``0'' setting to ensure that the transverse 
instrumentation platform of the head is horizontal within \1/2\ degree. 
The test dummy remains within the limits specified in S10.4.2.1 of 
Sec.  571.208 after any adjustment of the neck bracket.
    S5.3.7.2 Upper arms and hands. Position each test dummy as 
specified in S10.2 and S10.3 of Sec.  571.208 of this Part.
    S5.3.7.3 Torso. Position each test dummy as specified in S10.4.1.1, 
S10.4.1.2, and S10.4.2.1 of Sec.  571.208 of this Part, except that the 
midsagittal plane of the dummy is aligned within 15 mm of the head 
restraint centerline. If the midsagittal plane of the dummy cannot be 
aligned within 15 mm of the head restraint centerline then align the 
midsagittal plane of the dummy as close as possible to the head 
restraint centerline.
    S5.3.7.4 Legs. Position each test dummy as specified in S10.5 of 
Sec.  571.208 of this Part, except that final adjustment to accommodate 
placement of the feet in accordance with S5.3.7.5 of this section is 
permitted.
    S5.3.7.5 Feet. Position each test dummy as specified in S10.6 of 
Sec.  571.208 of this Part, except that for rear outboard designated 
seating positions the feet of the test dummy are placed flat on the 
floorpan and beneath the front seat as far forward as possible without 
front seat interference. For rear outboard designated seating 
positions, if necessary, the distance between the knees can be changed 
in order to place the feet beneath the seat.
    S5.3.8 Accelerate the dynamic test platform to 17.3  
0.6 km/h. All of the points on the acceleration vs. time curve fall 
within the corridor described in Figure 1 and Table 1 when filtered to 
channel class 60, as specified in the SAE Recommended Practice J211/1 
(March 1995). Measure the maximum posterior angular displacement.
    S5.3.9 Calculate the angular displacement from the output of 
instrumentation placed in the torso and head of the test dummy and an 
algorithm capable of determining the relative angular displacement to 
within one degree and conforming to the requirements of a 600 Hz 
channel class, as specified in SAE Recommended Practice J211/1, March 
1995. No data generated after 200 ms from the beginning of the forward 
acceleration are used in determining angular displacement of the head 
with respect to the torso.
    S5.3.10 Calculate the HIC15 from the output of 
instrumentation placed in the head of the test dummy, using the 
equation in S4.3.1(b) of this section and conforming to the 
requirements for a 1000 Hz channel class as specified in SAE 
Recommended Practice J211/1 (March 1995). No data generated after 200 
ms from the beginning of the forward acceleration are used in 
determining HIC.
    S5.4 Procedures for folding or retracting head restraints for 
unoccupied rear outboard designated seating positions.
    (a) Demonstrate compliance with S4.4 (a) of this section, using a 
5th percentile female Hybrid III test dummy specified in 49 CFR Part 
572, Subpart O, in accordance with the following procedure--
    (1) Position the test dummy in the seat such that the dummy's 
midsaggital plane is aligned within the 15 mm of the head restraint 
centerline and is parallel to a vertical plane parallel to the vehicle 
longitudinal centerline.
    (2) Hold the dummy's thighs down and push rearward on the upper 
torso to maximize the dummy's pelvic angle.
    (3) Place the legs as close as possible to 90 degrees to the 
thighs. Push rearward on the dummy's knees to force the pelvis into the 
seat so there is no gap between the pelvis and the seat back or until 
contact occurs between the back of the dummy's calves and the front of 
the seat cushion such that the angle between the dummy's thighs and 
legs begins to change.
    (4) Note the position of the head restraint. Remove the dummy from 
the seat. If the head restraint returns to a retracted position upon 
removal of the dummy, manually place it in the noted position. 
Determine compliance with the height requirements of S4.2.1 of this 
section by using the test procedures of S5.2.1 of this section.
    (b) Demonstrate compliance with S4.4 (b) of this section in 
accordance with the following procedure:
    (1) Place the rear head restraint in any position meeting the 
requirements of S4.2 of this section;
    (2) Strike a line on the head restraint. Measure the angle or range 
of angles of the head restraint reference line as projected onto a 
vertical longitudinal vehicle plane. Alternatively, measure the torso 
reference line angle with the SAE J826 (July 1995) manikin;
    (3) Fold or retract the head restraint to a position in which its 
minimum height is less than that specified in S4.2.1 (b) of this 
section;
    (4) Determine the minimum change in the head restraint reference 
line angle as projected onto a vertical longitudinal vehicle plane from 
the angle or range of angles measured in 5.4(b)(2). Alternatively, 
determine the change in the torso reference line angle with the SAE 
J826 (July 1995) manikin.
    S6 Vehicles manufactured on or after September 1, 2009, and before 
September 1, 2010 (Phase-in of Sec.  571.202a).
    (a) For vehicles manufactured for sale in the United States on or 
after September 1, 2009, and before September 1, 2010, a percentage of 
the manufacturer's production, as specified in S6.1, shall meet the 
requirements

[[Page 25520]]

specified in this Sec.  571.202a without regard to any option to comply 
with the standard in Sec.  571.202 or with the European regulations 
referenced in S4.3(a) of Sec.  571.202. So long as this percentage 
requirement is met, a vehicle may comply with the standard in this 
Sec.  571.202a, with the standard in Sec.  571.202, or with the 
European regulations referenced in S4.3(a) of Sec.  571.202.
    (b) Notwithstanding S6(a), vehicles that are manufactured in two or 
more stages or that are altered (within the meaning of 49 CFR 567.7) 
after having previously been certified in accordance with Part 567 of 
this chapter may comply with the standard in this Sec.  571.202a, with 
the standard in Sec.  571.202, or with the European regulations 
referenced in S4.3(a) of Sec.  571.202.
    S6.1 Phase-in percentage. For vehicles manufactured by a 
manufacturer on or after September 1, 2009, and before September 1, 
2010, the amount of vehicles complying with S6(a) shall be not less 
than 80 percent of:
    (a) If the manufacturer has manufactured vehicles for sale in the 
United States during both of the two production years prior to 
September 1, 2009, the manufacturer's average annual production of 
vehicles manufactured on or after September 1, 2007, and before 
September 1, 2010, or
    (b) The manufacturer's production on or after September 1, 2009, 
and before September 1, 2010.
    S6.2 Vehicles produced by more than one manufacturer.
    S6.2.1 For the purpose of calculating average annual production of 
vehicles for each manufacturer and the number of vehicles manufactured 
by each manufacturer under S6.1, a vehicle produced by more than one 
manufacturer shall be attributed to a single manufacturer as follows, 
subject to S6.2.2.
    (a) A vehicle that is imported shall be attributed to the importer.
    (b) A vehicle manufactured in the United States by more than one 
manufacturer, one of which also markets the vehicle, shall be 
attributed to the manufacturer that markets the vehicle.
    S6.2.2 A vehicle produced by more than one manufacturer shall be 
attributed to any one of the vehicle's manufacturers specified by an 
express written contract, reported to the National Highway Traffic 
Safety Administration under 49 CFR Part 585, between the manufacturer 
so specified and the manufacturer to which the vehicle would otherwise 
be attributed under S6.2.1.
    S7. Vehicles manufactured on or after September 1, 2010, and before 
September 1, 2011 (Phase-in of rear seat requirements of Sec.  
571.202a).
    (a) For vehicles manufactured for sale in the United States on or 
after September 1, 2010, and before September 1, 2011 a percentage of 
the manufacturer's production of vehicles equipped with rear outboard 
head restraints, as specified in S7.1, shall meet the requirements 
specified in this Sec.  571.202a for rear head restraints.
    (b) Vehicles that are manufactured in two or more stages or that 
are altered (within the meaning of 49 CFR 567.7) after having 
previously been certified in accordance with Part 567 of this chapter 
are not subject to the requirement specified in S7(a).
    S7.1 Phase-in percentage. For vehicles manufactured by a 
manufacturer on or after September 1, 2010, and before September 1, 
2011, the amount of vehicles equipped with rear outboard head 
restraints complying with S7(a) shall be not less than 80 percent of:
    (a) If the manufacturer has manufactured vehicles for sale in the 
United States during both of the two production years prior to 
September 1, 2010, the manufacturer's average annual production of 
vehicles equipped with rear outboard head restraints manufactured on or 
after September 1, 2008, and before September 1, 2011, or
    (b) The manufacturer's production of vehicles equipped with rear 
outboard head restraints on or after September 1, 2010, and before 
September 1, 2011.
    S7.2 Vehicles produced by more than one manufacturer.
    S7.2.1 For the purpose of calculating average annual production of 
vehicles for each manufacturer and the number of vehicles manufactured 
by each manufacturer under S6.1, a vehicle produced by more than one 
manufacturer shall be attributed to a single manufacturer as follows, 
subject to S7.2.2.
    (a) A vehicle that is imported shall be attributed to the importer.
    (b) A vehicle manufactured in the United States by more than one 
manufacturer, one of which also markets the vehicle, shall be 
attributed to the manufacturer that markets the vehicle.
    S7.2.2 A vehicle produced by more than one manufacturer shall be 
attributed to any one of the vehicle's manufacturers specified by an 
express written contract, reported to the National Highway Traffic 
Safety Administration under 49 CFR Part 585, between the manufacturer 
so specified and the manufacturer to which the vehicle would otherwise 
be attributed under S7.2.1.
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PART 585--PHASE-IN REPORTING REQUIREMENTS

0
4. The authority citation for Part 585 of Title 49 continues to read as 
follows:

     Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166; 
delegation of authority at 49 CFR 1.50.


0
5. Amend Part 585 by adding Subpart J to read as follows:

Subpart J--Head Restraints Phase-in Reporting Requirements

Sec.
585.91 Scope.
585.92 Purpose.
585.93 Applicability.
585.94 Definitions.
585.95 Response to inquiries.
585.96 Reporting requirements.
585.97 Records.

Subpart J--Head Restraints Phase-in Reporting Requirements


Sec.  585.91  Scope.

    This subpart establishes requirements for manufacturers of 
passenger cars, multipurpose passenger vehicles, trucks and buses with 
a GVWR of 4,536 kg or less to submit a report, and maintain records 
related to the report, concerning the number of vehicles that meet the 
requirements of Standard No. 202a.


Sec.  585.92  Purpose.

    The purpose of these reporting requirements is to assist the 
National Highway Traffic Safety Administration in determining whether a 
manufacturer has complied with Standard No. 202a.


Sec.  585.93  Applicability.

    This subpart applies to manufacturers of passenger cars, 
multipurpose passenger vehicles, trucks and buses with a GVWR of 4,536 
kg or less. However, it does not apply to manufacturers whose 
production consists exclusively of vehicles that are manufactured in 
two or more stages or that are altered (within the meaning of 49 CFR 
567.7) after having previously been certified in accordance with Part 
567 of this chapter.


Sec.  585.94  Definitions.

    Production year means the 12-month period between September 1 of 
one year and August 31 of the following year, inclusive.


Sec.  585.95  Response to inquiries.

    (a) Production year ending August 31, 2010. At any time during the 
production year, each manufacturer must, upon request from the Office 
of Vehicle Safety Compliance, provide information identifying the 
vehicles (by make, model and vehicle identification

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number) that have been certified as complying with Sec.  571.202a 
without regard to any option to comply with the standard in Sec.  
571.202 or with the European regulations referenced in S4.3(a) of Sec.  
571.202.
    (b) Production year ending August 31, 2011. At any time during the 
production year, each manufacturer must, upon request from the Office 
of Vehicle Safety Compliance, provide information identifying the 
vehicles (by make, model and vehicle identification number) that have 
been certified as complying with the requirements specified in Sec.  
571.202a for rear head restraints.


Sec.  585.96  Reporting Requirements.

    (a) Production year ending August 31, 2010.
    (1) General reporting requirements. Within 60 days after the end of 
the production year ending August 31, 2010, each manufacturer must 
submit a report to the National Highway Traffic Safety Administration 
concerning its compliance with the head restraint requirements 
specified in Sec.  571.202a, without regard to any option to comply 
with the standard in Sec.  571.202 or with the European regulations 
referenced in S4.3(a) of Sec.  571.202, for its passenger cars, trucks, 
buses and multipurpose passenger vehicles produced in that year. The 
report must provide the information specified in paragraph (2) of this 
section and in Sec.  585.2 of this part.
    (2) Report content.
    (i) Basis for phase-in production goals. Each manufacturer must 
provide the number of passenger cars and multipurpose passenger 
vehicles, trucks and buses with a GVWR of 4,536 kg or less manufactured 
for sale in the United States. The number must be either the 
manufacturer's average annual production of vehicles manufactured on or 
after September 1, 2007 and before September 1, 2010, or, at the 
manufacturer's option, the manufacturer's production on or after 
September 1, 2009 and before September 1, 2010. A new manufacturer that 
has not previously manufactured these vehicles for sale in the United 
States must report the number of such vehicles manufactured during the 
production period beginning on or after September 1, 2009 and before 
September 1, 2010.
    (ii) Production. Each manufacturer must report for the production 
year ending August 31, 2010: The total number of passenger cars, 
multipurpose passenger vehicles, trucks, and buses with a gross vehicle 
weight rating of 4,536 kg or less that meet Sec.  571.202a, without 
regard to any option to comply with the standard in Sec.  571.202 or 
with the European regulations referenced in S4.3(a) of Sec.  571.202.
    (b) Production year ending August 31, 2011.
    (1) General reporting requirements. Within 60 days after the end of 
the production year ending August 31, 2011, each manufacturer must 
submit a report to the National Highway Traffic Safety Administration 
concerning its compliance with the rear head restraint requirements 
specified in Sec.  571.202a. The report must provide the information 
specified in paragraph (2) of this section and in Sec.  585.2 of this 
part.
    (2) Report content.
    (i) Basis for phase-in production goals. Each manufacturer must 
provide the number of passenger cars and multipurpose passenger 
vehicles, trucks and buses with a GVWR of 4,536 kg or less manufactured 
for sale in the United States with rear head restraints. The number 
must be either the manufacturer's average annual production of vehicles 
with rear head restraints manufactured on or after September 1, 2008 
and before September 1, 2011, or, at the manufacturer's option, the 
manufacturer's production on or after September 1, 2010 and before 
September 1, 2011. A new manufacturer that has not previously 
manufactured these vehicles for sale in the United States must report 
the number of such vehicles manufactured during the production period 
on or after September 1, 2010 and before September 1, 2011.
    (ii) Production. Each manufacturer must report for the production 
year ending August 31, 2011: The total number of passenger cars, 
multipurpose passenger vehicles, trucks, and buses with a gross vehicle 
weight rating of 4,536 kg or less that meet the rear head restraint 
requirements of Sec.  571.202a.


Sec.  585.97  Records.

    Each manufacturer must maintain records of the Vehicle 
Identification Number for each vehicle for which information is 
reported under Sec.  585.96 until December 31, 2007.

    Issued on: April 16, 2007.
Nicole R. Nason,
Administrator.
[FR Doc. 07-2011 Filed 5-3-07; 8:45 am]
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