25484 Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 

1 Docket No. NHTSA–2004–19807. 

2The 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. 

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. 

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 oneyear 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: Louis.Molino@dot.gov). 

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. 

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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Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 25485 

3Non-contact Abbreviated Injury Scale (AIS) 1 

neck. 

4The 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. 

5 Jakobsson et al., Analysis of Head and Neck 

Responses in Rear End Impacts—A New HumanLike Model. Volvo Car Corporation Safety Report 

(1994). 

6Olsson et al., An In-depth Study of Neck Injuries 

in Rear-end Collisions. International IRCOBI 

Conference, pp 269–280 (1990). 

7Farmer, 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 WhiplashAssociated Disorders (1999), Vancouver, British 

Columbia. 

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. 

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. 

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

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

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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9The report was included in Docket No. 96–22, 

Notice 1. It is noted that this NHTSA docket predates the DOT DMS system. 

10The 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. 

11 254 mm (10 in) for restraints on bench-type 

seats, and 171 mm (6.75 in) for restraints on 

individual seats. 

12The 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. 

13Changes 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. 

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. 

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

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 Hpoint. 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. 

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. 

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-totorso 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. 

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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Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 25487 

14The 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). 

15The 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) threedimensional manikin (SAE J826 manikin), which 

simulates the actual pivot center of the human torso 

and thigh. 

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. 

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. 

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 


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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 carryforward 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 


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16 Docket No. NHTSA–2006–23848. 

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. 

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 


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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 


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17We 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. 

‘‘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. 

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. 


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18 GTR HR–7–5 (http://www.unece.org/trans/ 

main/wp29/wp29wgs/wp29grsp/head07.html). 

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. 

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 


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Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 25493 

19 ‘‘Technical Analysis Relevant to Petitions for 

Reconsideration to the December 14, 2004 FMVSS 

202a—Head Restraints Final Rule.’’ 

20The 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. 

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. 

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. 

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, 


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21SAE J1100—Motor Vehicle Dimensions. All 

1999–2000 make and model data submitted to 

NHTSA. The data ranged from 18 to 28 degrees. 

22 ‘‘Technical Analysis Relevant to Petitions for 

Reconsideration to the December 14, 2004 FMVSS 

202a—Head Restraints Final Rule.’’ 

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. 

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 vehiclespecific 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. 

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 


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23For 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. 

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. 

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. 

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

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 


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25496 Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 

26 ‘‘Technical Analysis Relevant to Petitions for 

Reconsideration to the December 14, 2004 FMVSS 

202a—Head Restraints Final Rule.’’ 

27The Alliance also made this recommendation 

for the GTR that is under development. 

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. 

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. 

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 


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28 DOT HS 809 957, ‘‘Rear Seat Stowable Head 

Restraint Non-Use Position Torso Angle Study,’’ 

November 2005. 

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 nonuse 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 nonuse 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 nonuse position.28

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. 


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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 

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 oneyear 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 shortstatured 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 × 55 mm HLE × 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 headto-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 


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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.) 

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. 

biomechanical basis for the 

development of the head-to-torso 

rotation limit. 

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: 

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. 

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 costbenefit 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 


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31Copies of the test reports will be placed in the 

docket. 

32See the docket for this document. 

33We 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. 

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. 

35 Insurance Special Report —Head Restraints and 

Personal Injury Protection Losses, (2005). Highway 

Loss Data Institute (HLDI). 36 Docket No. NHTSA–2004–19807–21. 

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 headto-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. 

TABLE I.—NHTSA TESTING OF

MY2006 ACTIVE HEAD RESTRAINTS

Vehicle 

Head-to-torso 

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. 

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. 

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, nonactive), 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. 

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. 

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 DV 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 DV. 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 


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Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 25501 

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. 

38 ‘‘Technical Analysis Relevant to Petitions for 

Reconsideration to the December 14, 2004 FMVSS 

202a—Head Restraints Final Rule.’’ 

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 DV 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 DV, 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. 

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 DV of 15 km/h. For this group, 

the average mean acceleration was 5.3 g 

and the average DV was 20 km/h. The 

FMVSS No. 202a crash pulse has a 5.6 

g average acceleration and 17.3 km/h 

DV. 

We are including in the Technical 

Analysis 38 noted earlier additional 

analysis concerning why we believe that 

the sled test pulse is appropriate. 

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 


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25502 Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 

39We 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.’’ 

40 Docket No. NHTSA–2004–19807–20. 

41 ‘‘Technical Analysis Relevant to Petitions for 

Reconsideration to the December 14, 2004 FMVSS 

202a—Head Restraints Final Rule.’’ 

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. 

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. 

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 Hpoint 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. 

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 


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Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 25503 

42Technical Analysis Relevant to Petitions for 

Reconsideration to the December 14, 2004 FMVSS 

202a—Head Restraints Final Rule.’’ 

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. 

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 


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25504 Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 

43This 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. 

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. 

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 


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Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 25505 

44 ‘‘Technical Analysis Relevant to Petitions for 

Reconsideration to the December 14, 2004 FMVSS 

202a—Head Restraints Final Rule.’’ 45 Docket No. NHTSA–2004–19807–13 

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

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 outboarddesignated 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. 

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. 


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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 twopassenger 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 


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46As 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). 

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. 

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 


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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. 


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Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 25509 

47 ‘‘Technical Analysis Relevant to Petitions for 

Reconsideration to the December 14, 2004 FMVSS 

202a—Head Restraints Final Rule.’’ 

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. 

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 


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25510 Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 

48 ‘‘Technical Analysis Relevant to Petitions for 

Reconsideration to the December 14, 2004 FMVSS 

202a—Head Restraints Final Rule.’’ 

49 ‘‘Technical Analysis Relevant to Petitions for 

Reconsideration to the December 14, 2004 FMVSS 

202a—Head Restraints Final Rule.’’ 

50 ‘‘Technical Analysis Relevant to Petitions for 

Reconsideration to the December 14, 2004 FMVSS 

202a—Head Restraints Final Rule.’’ 

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.’’ 

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. 

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. 

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 


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


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25512 Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 

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 


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51 62 FR 19885, April 23, 1997. 

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.’’ 

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. 

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. 

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 


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25514 Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 

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. 

■ In consideration of the foregoing, 49 

CFR parts 571 and 585 are amended as 

follows: 

PART 571—FEDERAL MOTOR 

VEHICLE SAFETY STANDARDS 

■ 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. 

■ 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 § 571.202, with the 

European regulations referenced in S4.3 

of this § 571.202, or with the standard 

in § 571.202a. For vehicles 

manufactured on or after September 1, 

2009 and before September 1, 2010, 

manufacturers may comply with the 

standard in this § 571.202 or with the 

European regulations referenced in S4.3 

of this § 571.202, instead of the standard 

in § 571.202a, only to the extent 

consistent with phase-in specified in 

§ 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. 

* * * * * 

■ 3. Section 571.202a is revised to read 

as follows: 

§ 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 

§ 571.202a, with the standard in 

§ 571.202, or with the European 

regulations referenced in S4.3(a) of 

§ 571.202. For vehicles manufactured on 

or after September 1, 2009 and before 

September 1, 2010, manufacturers may 

comply with the standard in § 571.202 

or with the European regulations 

referenced in S4.3(a) of § 571.202, 

instead of the standard in this 

§ 571.202a, only to the extent consistent 

with the phase-in specified in this 

§ 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 


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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/s2 (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 


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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: 

HIC

t t

a dt t t r

t

t

= ( ) −















 ( ) − ∫ 1

2 1

2 5

2 1

1

2

.

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 § 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 


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


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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 

μm, 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 Hpoint 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 μm, 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 § 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 


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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 § 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 § 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 § 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 § 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 § 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 

§ 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 

§ 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 

§ 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 


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specified in this § 571.202a without 

regard to any option to comply with the 

standard in § 571.202 or with the 

European regulations referenced in 

S4.3(a) of § 571.202. So long as this 

percentage requirement is met, a vehicle 

may comply with the standard in this 

§ 571.202a, with the standard in 

§ 571.202, or with the European 

regulations referenced in S4.3(a) of 

§ 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 

§ 571.202a, with the standard in 

§ 571.202, or with the European 

regulations referenced in S4.3(a) of 

§ 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 § 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 

§ 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. 

BILLING CODE 4910–59–P 


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BILLING CODE 4910–59–C 

PART 585—PHASE-IN REPORTING 

REQUIREMENTS 

■ 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. 

■ 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 

§ 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. 

§ 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. 

§ 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. 

§ 585.94 Definitions. 

Production year means the 12-month 

period between September 1 of one year 

and August 31 of the following year, 

inclusive. 

§ 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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25524 Federal Register / Vol. 72, No. 86 / Friday, May 4, 2007 / Rules and Regulations 

number) that have been certified as 

complying with § 571.202a without 

regard to any option to comply with the 

standard in § 571.202 or with the 

European regulations referenced in 

S4.3(a) of § 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 § 571.202a for rear head 

restraints. 

§ 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 § 571.202a, 

without regard to any option to comply 

with the standard in § 571.202 or with 

the European regulations referenced in 

S4.3(a) of § 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 § 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 § 571.202a, 

without regard to any option to comply 

with the standard in § 571.202 or with 

the European regulations referenced in 

S4.3(a) of § 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 § 571.202a. 

The report must provide the information 

specified in paragraph (2) of this section 

and in § 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 § 571.202a. 

§ 585.97 Records. 

Each manufacturer must maintain 

records of the Vehicle Identification 

Number for each vehicle for which 

information is reported under § 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] 

BILLING CODE 4910–59–P 


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