Federal Register, Volume 89 Issue 182 (Thursday, September 19, 2024)

[Federal Register Volume 89, Number 182 (Thursday, September 19, 2024)]
[Proposed Rules]
[Pages 76922-77010]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-20653]

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Vol. 89

Thursday,

No. 182

September 19, 2024

Part II

Department of Transportation

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National Highway Traffic Safety Administration

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49 CFR Part 571

Federal Motor Vehicle Safety Standards; Pedestrian Head Protection,
Global Technical Regulation No. 9; Incorporation by Reference; Proposed
Rule

Federal Register / Vol. 89 , No. 182 / Thursday, September 19, 2024 /
Proposed Rules

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. NHTSA-NHTSA-2024-0057]
RIN 2127-AK98

Federal Motor Vehicle Safety Standards; Pedestrian Head
Protection, Global Technical Regulation No. 9; Incorporation by
Reference

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

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: NHTSA proposes a new Federal Motor Vehicle Safety Standard
(FMVSS) that would ensure passenger vehicles with a gross vehicle
weight rating (GVWR) of 4,536 kilograms (kg) (10,000 pounds (lb)) or
less are designed to mitigate the risk of serious to fatal injury in
child and adult pedestrian crashes. The proposed standard would
establish test procedures simulating a head-to-hood impact and
performance requirements to minimize the risk of head injury. This NPRM
is based on a Global Technical Regulation (GTR) on pedestrian
protection, with focused enhancements to address safety problems and a
regulatory framework unique to the United States.

DATES: Comments must be received on or before November 18, 2024.
Proposed compliance date: The first September 1, two (2) years
following the date of publication of any final rule in the Federal
Register, with optional early compliance permitted. Final-stage
manufacturers and alterers would be provided an additional year to
comply.

ADDRESSES: You may submit comments to the docket number identified in
the heading of this document by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the online instructions for submitting
comments.
Mail: Docket Management Facility, M-30, U.S. Department of
Transportation, West Building, Ground Floor, Rm. W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.
Hand Delivery or Courier: West Building, Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE, between 9 a.m. and 5 p.m.
Eastern Time, Monday through Friday, except Federal holidays. To be
sure someone is there to help you, please call (202) 366-9332 before
coming.
Regardless of how you submit your comments, please mention the
docket number of this document.
Instructions: For detailed instructions on submitting comments and
additional information on the rulemaking process, see the Public
Participation heading of the Supplementary Information section of this
document. Note that all comments received will be posted without change
to https://www.regulations.gov, including any personal information
provided.
Docket: For access to the docket to read background documents or
comments received, go to www.regulations.gov, or the street address
listed above. To be sure someone is there to help you, please call
(202) 366-9322 before coming. Follow the online instructions for
accessing the dockets.

FOR FURTHER INFORMATION CONTACT: For non-legal issues: Vincent Wu,
Office of Crashworthiness Standards (telephone: (202) 366-1740, fax
(202) 493-2990). For legal issues: Matthew Filpi, Office of the Chief
Counsel (telephone: 202-366-3179). The mailing address for these
officials is: National Highway Traffic Safety Administration, 1200 New
Jersey Avenue SE, Washington, DC 20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary
A. This Proposed Standard
B. Potential Impacts of the Rulemaking
II. Safety Need
III. Foundations of the Proposal
IV. The Global Technical Regulation
A. Introduction
B. GTR 9
C. Further Observations About the Differences Between This NPRM
and the GTR
V. Approach of the Proposed Standard
A. Overview
B. Relevance to the Involved Vehicles
C. Advantages of Headform Component Tests
D. Head Injury Criterion (HIC)
E. Speed and Angle at Which the Headforms Would Impact the Hood
VI. Defining the Relevant Areas Subject to the Standard
A. Determining the Hood Top
B. Hood Area
C. Defining the Child Headform Test Area and the Adult Headform
Test Area
VII. Proposed Requirements and Assessing Compliance
A. Amount of Hood Area That Must Conform to HIC 1000
B. Manufacturer Designations of HIC1700 Areas
C. First Point of Contact
D. Consideration Related to the Amount of Test Area That Must
Meet the HIC100 and HIC1700 Limits
E. Considerations for Expansion of Test Area When It Is Less
Than Two Thirds of the Numerical Value of the Hood Area
VIII. GTR 9 Terminology and Amendment 3
A. Comparison of Terminology
B. Amendment 3
IX. Headform Characteristics
A. General
B. Qualification Limits
C. Repeatability and Reproducibility
X. Other Issues
A. Active Hoods
XI. Effect on Other Standards
XII. Proposed Lead Time
XIII. Benefits and Costs
XIV. Considered Alternatives
XV. Rulemaking Analyses and Notices
XVI. Public Participation

I. Executive Summary

Improving pedestrian safety is a high priority of the Department of
Transportation. Data show pedestrian fatalities increasing
substantially in recent years. NHTSA issues this NPRM in an effort to
address this safety problem. This NPRM proposes a new Federal Motor
Vehicle Safety Standard (FMVSS) that would ensure that passenger
vehicles are designed to reduce the risk of serious to fatal child and
adult head injury in pedestrian crashes. This rulemaking initiates the
process of adopting a Global Technical Regulation (GTR) on pedestrian
protection as an FMVSS, with focused enhancements to the GTR to address
safety problems and a regulatory framework unique to the U.S. In
addition, this NPRM furthers the goals and policies of DOT's January
2022 National Roadway Safety Strategy, which describes the five key
objectives of the Department's Safe System Approach: safer people,
safer roads, safer vehicles, safer speeds, and post-crash care.
New Federal Motor Vehicle Safety Standard No. 228, Pedestrian head
protection, would apply to passenger cars, light trucks (including
pickups), multipurpose passenger vehicles (MPVs) (MPVs include sport
utility vehicles (SUVs), crossover vehicles and vans) and buses with a
GVWR of 4,536 kg (10,000 lb) or less. The standard would require
vehicles to meet a head injury criterion (HIC) when subjected to
testing simulating a head-to-hood impact. The vehicles would have to
reduce the risk of serious to fatal head injury to child and adult
pedestrians in impacts at vehicle speeds up to 40 km/h (25 mph), which
encompass about 70 percent of pedestrian injuries from vehicle impacts.
Moreover, it is expected the standard would be beneficial even at
higher speeds.\1\ This

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NPRM advances NHTSA's objective of adopting a motor vehicle
crashworthiness safety standard to ensure that passenger vehicles are
designed to mitigate the risk of serious to fatal child and adult
pedestrian head injury.
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\1\ Hu, J., Lin, Y.-S., Boyle, K., Bonifas, A., Reed, M.P.,
Gupta, V., & Lin, C.H. (2023, November). Pedestrian safety:
assessment of crashworthiness test procedures (Report No. DOT HS 813
518). National Highway Traffic Safety Administration.
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This NPRM is part of a multi-step approach to enhance vehicle
performance against pedestrian injury. First, it initiates the process
of adopting Global Technical Regulation No. 9 (GTR 9), ``Pedestrian
safety,'' into the Federal safety standards. NHTSA has collaborated
with governments internationally to develop GTR 9, and numerous
countries have adopted the GTR into their regulations. FMVSS No. 228
would establish a pedestrian standard domestically, to ensure that all
vehicles with a GVWR of 4,536 kg (10,000 lb.) or less manufactured in
or imported into the United States--including a sub-group of light
trucks (large pickups and large SUVs) more common in the U.S. than in
other parts of the world--mitigate the risk of serious head injury to
pedestrians.
Second, the standard would provide a regulatory counterpart to
NHTSA's planned crashworthiness pedestrian protection testing program
in the New Car Assessment Program (NCAP) in the near term.\2\ On May
26, 2023, NHTSA published an NCAP Request for Comment (NCAP RFC)
proposing to adopt a crashworthiness pedestrian protection program into
NHTSA's NCAP.\3\ NCAP would build on proposed FMVSS No. 228 and
incorporate enhanced crashworthiness tests into NCAP that go beyond the
specifications of proposed FMVSS No. 228. NCAP remains a consumer
information program that provides consumers with vehicle safety
information for their purchasing decisions. Providing this information
encourages manufacturers to voluntarily make changes to vehicles that
reflect positively in the NCAP safety information and thereby improves
safety through the marketplace. FMVSSs, on the other hand, are
mandatory and mandate at least a minimum level of safety that all new
vehicles must provide to every purchaser. NHTSA has observed that, in
the case of both electronic stability control and rear visibility
cameras, only approximately 70 percent of vehicles had these
technologies during the time they were part of NCAP. Thus, while NCAP
serves a vital safety purpose, NHTSA also recognizes its limitations in
ensuring that every vehicle provides the performance necessary to
provide the requisite level of safety to all purchasers. Because only
an FMVSS can ensure that all vehicles are equipped with technologies
and vehicle designs that meet the specified performance requirements,
NCAP can supplement but not substitute for the FMVSS. The FMVSS remains
NHTSA's core way of ensuring that all motor vehicles provide the
requisite level of safety performance, and provide it within a
practicable timeframe. Although the NCAP program provides valuable
safety-related information to consumers in a simple and easy-to-
understand manner, the agency believes that the proposed rule is
necessary to achieve the highest level of pedestrian safety feasible
and at the fastest achievable timeframe based on the performance
requirements and lead time specified in the proposed rule. Additional
discussion on the NCAP RFC is provided later in this preamble.
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\2\ NHTSA has proposed a roadmap for the agency's plans to
upgrade NCAP in phases over the next several years. 87 FR 13452,
March 9, 2022, extension of comment period, 87 FR 27200.
\3\ 88 FR 34366, May 26, 2023. The proposed NCAP pedestrian
protection program would incorporate crashworthiness tests similar
to those used by the European New Car Assessment Programme (Euro
NCAP). Euro NCAP's tests are closely aligned with those in GTR 9.
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Third, this rulemaking proposing FMVSS No. 228 is intended to work
hand-in-hand with the growth and expansion of automatic emergency
braking (AEB) technologies. An AEB system uses various sensor
technologies and sub-systems that work together to detect when the
vehicle is in a crash imminent situation, to automatically apply the
vehicle brakes if the driver has not done so, or to apply more braking
force to supplement the driver's braking. AEB systems were originally
developed to detect a crash imminent situation with a lead vehicle, but
AEB is in a state of rapid advancement and some of the systems on the
market now also warn about, and respond to, an imminent collision with
a pedestrian. Pedestrian AEB (PAEB) systems are designed to stop the
vehicle automatically before striking a pedestrian or reduce the speed
at which an impact occurs if the vehicle's initial speed is too high to
avoid impact. On May 9, 2024, NHTSA published a final rule requiring
AEB and PAEB systems on light vehicles which adopts FMVSS No. 127.\4\
FMVSS No. 127 builds on a voluntary commitment, announced by NHTSA in
March 2016, by 20 vehicle manufacturers to make lead-vehicle AEB a
standard feature on light vehicles, though that commitment did not
include PAEB.\5\ When new vehicles are equipped with PAEB, we
anticipate that fewer pedestrians will be struck. For some impacts that
cannot be avoided due to the closing speed of the vehicle (the relative
speed between the vehicle and what it is approaching, in this case, the
pedestrian), PAEB will lower the vehicle's speed so more impacts will
be at speeds of 40 km/h (25 mph) or less, which is the velocity range
FMVSS No. 228 is designed to replicate. FMVSS No. 228 would address
those crashes and ensure the vehicles mitigate the risk of serious to
fatal head injury in these impacts.\6\ PAEB will eliminate many
pedestrian impacts and reduce the impact of those crashes that do
occur. This NPRM, if adopted, would further reduce the risk of serious
injury or death from head injuries if a pedestrian strikes the hood of
a vehicle. NHTSA has accounted for the effect of FMVSS No. 127 in
estimating the economic impacts of this rulemaking.
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\4\ 88 FR 38632, Docket NHTSA-2023-0021. The NPRM applies to
passenger vehicles with a GVWR of 4,536 kg (10,000 lb) or less. The
action can also be found in the Unified Agenda of Regulatory and
Deregulatory Actions, RIN 2127-AM37.
\5\ The 20 vehicle manufacturers represent more than 99 percent
of the U.S. market. The commitment was to have AEB on virtually all
(at least 95 percent) new passenger cars, light trucks, and MPVs
with a GVWR of 8,500 pounds or less no later than September 1, 2022,
and a standard feature on virtually all light trucks and MPVs with a
GVWR between 8,501 pounds and 10,000 pounds no later than Sept. 1,
2025. Most manufacturers met the 2022 mark, but some did not
(https://www.iihs.org/news/detail/three-more-automakers-fulfill-pledge-to-make-autobrake-nearly-universal). Other agency data
indicate about 87% of production has PAEB. https://www.transportation.gov/NRSS/SaferVehicles. The voluntary commitment
did not involve a pedestrian AEB component. NHTSA's NPRM would
require an AEB system that detects and reacts to both lead vehicles
and pedestrians and would increase the lead-vehicle performance
required of AEB over that described in the voluntary commitment.
\6\ Yanagisawa, M., Swanson, E., Azeredo, P., & Najm, W.G.
(2017, April). Estimation of potential safety benefits for
pedestrian crash avoidance/mitigation systems. (Report No. DOT HS
812 400). Washington, DC: National Highway Traffic Safety
Administration. https://www.nhtsa.gov/sites/nhtsa.gov/files/documents/812400_pcambenefitsreport.pdf.
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This NPRM proposes FMVSS No. 228 and aligns with the goals of DOT's
January 2022 National Roadway Safety Strategy, which describes the five
key objectives of the Department's Safe System Approach: safer people,
safer roads, safer vehicles, safer speeds, and post-crash care. FMVSS
No. 228 would mandate requirements for safer vehicles and leverage
advanced crash avoidance technology like PAEB in conjunction with the
crashworthiness countermeasures based on GTR 9 to realize far-reaching
improvements to pedestrian safety. NHTSA also notes that although
research into vulnerable

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road users and vehicle safety measures has focused predominantly on
improving the protection of pedestrians, several effectiveness studies
have concluded that pedestrian safety measures like this NPRM's head
protection requirements would also be beneficial for cyclists.\7\
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\7\ Simms CK and Wood DO (2009), Pedestrian and cyclist impact--
a biomechanical perspective, Springer Science and Business Media,
Dordrecht Heidelberg London New York; see Chapter 10: The influence
of vehicle design on pedestrian and cyclist injuries.
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Issuance of this NPRM is also consistent with the goals of the
November 15, 2021, Infrastructure Investment and Jobs Act (IIJA).\8\
Section 24211 of IIJA, ``Global Harmonization,'' states that the
Secretary shall cooperate, to the maximum extent practicable, with
foreign governments, nongovernmental stakeholder groups, the motor
vehicle industry, and consumer groups with respect to global
harmonization of vehicle regulations as a means for improving motor
vehicle safety. This NPRM proposes to adopt an FMVSS for pedestrian
head protection founded on Global Technical Regulation No. 9,
``Pedestrian Safety'' (GTR 9). NHTSA collaborated with experts from
around the world to develop GTR 9. Establishing an FMVSS based on a
Global Technical Regulation aligns with the goals of IIJA Section
24211.
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\8\ Public Law 117-58.
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Although GTR 9 was established in 2008 when light trucks and vans
(LTVs), which includes large light trucks, MPVs (including SUVs) and
vans, were not as common as they are now in the U.S., LTVs did exist
then, and the GTR test procedure included in proposed FMVSS No. 228 was
developed to be relevant and applicable to these LTV vehicles. The test
procedure proposed for use in FMVSS No. 228 is relevant for use with
all light vehicles in the U.S. fleet because it is based on a Wrap
Around Distance (WAD) measurement appropriate for use with passenger
cars and LTVs. The defined ``Hood Area'' (subject to proposed FMVSS No.
228 coverage) is based on WAD, so any differences in head impact
locations for a given crash scenario between LTVs and passenger cars
are accounted for in the WAD-based test. As described in sections V.-
VII., in the proposed test, NHTSA would use impactor testing to
simulate a head-to-hood or head-to-fender top impact. It would specify
the use of two different impactors: one representative of the head of a
struck 6-year-old child (child headform) and another representative of
the head of a struck 50th percentile adult male pedestrian (adult
headform). The WAD measurement assures that the areas of the hood
subject to impactor testing are the areas likely to be struck by a
pedestrian's head. NHTSA has performed the WAD-based test of GTR 9 on a
wide variety of vehicles, including LTVs of various shapes and sizes.
These data have been used to generate the benefit-cost analysis for
this NPRM, which NHTSA discusses in the Preliminary Regulatory Impact
Analysis (PRIA) accompanying this NPRM. The PRIA, discussed in detail
in sections below, calculates benefits and costs separately for
passenger cars and LTVs.
Because the WAD-based test procedure of the GTR is technically
suitable for small and large vehicles, this NPRM's regulatory text
reflects the wording of GTR 9 to show the GTR's provisions implemented
in a Federal motor vehicle safety standard. Throughout this preamble,
however, NHTSA requests comments on the pros and cons of various
aspects of the NPRM's regulatory text, particularly with respect to the
areas of the vehicle that would be subject to headform testing strictly
using the GTR procedure. Throughout this preamble, NHTSA focuses
readers on ways NHTSA believes the proposed regulatory text could be
enhanced in a final rule to achieve more safety benefits in the U.S.
For example, we discuss an approach of potentially extending the test
area to the grille area on all large vehicles where the head of a child
or shorter adult pedestrian may be struck. With pedestrian injury and
fatality rates climbing, and with lessons learned from NHTSA's NCAP and
other NCAP programs engaged in headform testing of vehicle front ends,
NHTSA seeks to design FMVSS No. 228 to be as effective as possible to
address pedestrian safety needs in the U.S.
Accordingly, this NPRM discusses specific approaches that NHTSA is
considering to possibly tailor the GTR text for a final rule. While the
NPRM's regulatory text reflects the GTR's approaches and provides a
framework for an FMVSS based on those provisions, NHTSA may determine
to make changes in any final rule. Ultimately, NHTSA seeks to issue a
final rule that would ``fully meet the need in the U.S. for vehicle
safety.'' \9\
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\9\ Section I.B.1, 49 CFR part 553, appendix C, ``Statement of
Policy: Implementation of the United Nations/Economic Commission for
Europe (UN/ECE) 1998 Agreement of Global Technical Regulations--
Agency Policy Goals and Public Participation.''
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A. This Proposed Standard

In collisions between vehicles and pedestrians, the pedestrian is
typically struck from the side while walking across the vehicle's path.
When a pedestrian is struck in this manner, the first point of contact
typically occurs between the front-end of the vehicle and the lateral
aspect of the pedestrian's leg near the knee region. As the lower leg
becomes fully engaged with the vehicle's front-end, the leading edge of
the hood strikes the lateral aspect of the pedestrian's pelvis or upper
leg. Then, as the lower leg is kicked forward and away from the front-
end of the vehicle, the pedestrian's upper body swings abruptly
downward towards the hood until the head strikes the vehicle. Research
indicates that the linear head impact velocity ranges between 60 and
110 percent of the initial contact velocity.\10\
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\10\ Mizuno K et al. (2001), Summary Of IHRA Pedestrian Safety
WG Activities--Proposed Test Methods To Evaluate Pedestrian
Protection Afforded By Passenger Cars.
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Proposed FMVSS No. 228 is designed to mitigate injuries to
pedestrians hit from the side as described above. Most pedestrian
injuries (79%) and fatalities (83%) are caused by the frontal
structures of vehicles.\11\ Roughly two-thirds of these occur when
vehicle travel speeds are less than 40 km/h (25 mph).^{12 13}
Crash data show that pedestrian head injuries occur due to contacts to
all areas of vehicle front ends, including the hood.^{14 15}
The location the pedestrian's head strikes is dependent on the
pedestrian's size, the front configuration of the vehicle, and the
speed of impact. In a 40 km/h (25 mph) impact, roughly 15% of
pedestrian fatalities involve the pedestrian's head contacting the Hood
Top. This NPRM focuses on mitigating head injuries sustained from
contacting the hood and adjacent areas around the hood on the vehicle
front end.
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\11\ See table II.1.
\12\ Rosen E, Sander U (2009) Pedestrian fatality risk as a
function of car impact speed. Accident Analysis and Prevention,
2009;41:536-542.
\13\ Stammen JA et al (2002), A Demographic Analysis and
Reconstruction of Selected Cases from the Pedestrian Crash Data
Study, Paper No. 2002-01-0560, SAE International, Warrendale PA.
\14\ Yutaka Okamoto, Tomiji Sugimoto, Koji Enomoto & Junichi
Kikuchi (2003), Pedestrian Head Impact Conditions Depending on the
Vehicle Front Shape and Its Construction--Full Model Simulation,
Traffic Injury Prevention, 4:1, 74-82, DOI: 10.1080/15389580309856.
\15\ Bahman S. Roudsari, Charles N. Mock & Robert Kaufman (2005)
An Evaluation of the Association Between Vehicle Type and the Source
and Severity of Pedestrian Injuries, Traffic Injury Prevention, 6:2,
185-192, DOI: 10.1080/15389580590931680.
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Proposed FMVSS No. 228 would use impactor testing simulating a
head-to-

[[Page 76925]]

hood or head-to-fender top impact.\16\ It would specify the use of two
different impactors: one with a mass of 3.5 kg that is representative
of the head of a struck 6-year-old child (child headform) and another
with a mass of 4.5 kg representative of the head of a struck 50th
percentile adult male pedestrian (adult headform). The standard would
define various areas of a test vehicle \17\ hood (such as the Hood Top
and Hood Area) subject to testing in an objective and repeatable
manner. The Hood Area would be partially composed of the Child Headform
Test Area and the Adult Headform Test Area. The area likely to be
struck by a child pedestrian's head (the Child Headform Test Area)
would be tested with the child headform and the area likely to be
struck by an adult's head (the Adult Headform Test Area) would be
tested with the adult headform.\18\ The headforms would hit areas of
the vehicle hood at specific speeds and impact angles replicating a
real-world vehicle traveling at 40 km/h (25 mph) and impacting the
adult or child pedestrian.
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\16\ We note that the ``hood'' as defined in proposed FMVSS No.
228 would typically encompass portions of the fender top.
\17\ ``Test vehicle'' refers to the vehicle whose compliance
with proposed FMVSS No. 228 is being assessed.
\18\ This preamble occasionally refers to these two test areas
together as the ``Child and Adult Headform Test Areas.''
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The following figure generally depicts the areas of a vehicle that
would be subject to FMVSS No. 228 testing, particularly the Hood Top
and Hood Area (which share a boundary in this example and are contained
within the dashed lines), and the Child and Adult Headform Test Areas
(darkly shaded areas). The figure illustrates other terms and concepts
used in the proposed standard. All of the terms used in the figure are
fully explained in this preamble.
BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TP19SE24.002

BILLING CODE 4910-59-C
Proposed FMVSS No. 228 would specify performance requirements
limiting the accelerations measured by the headforms. The HIC must be
less than 1000 (HIC1000) over a certain portion of the Child and Adult
Headform Test Areas.\19\ The requisite portions would be derived as a
percentage of the overall Hood Area. Generally speaking, the portion of
the Child Headform Test Area that must

[[Page 76926]]

meet the HIC1000 requirement must be at least one-half of the numerical
value (numerical value of the area is calculated from a projection onto
a horizontal plane) of the Hood Area below what is called the ``WAD1700
line.'' \20\ Based on data showing the locations of child and adult
head impacts, this NPRM proposes that WAD1700 would be the boundary
between the Child Headform Test Area and the Adult Headform Test Area.
Secondly, the portion of the Combined Child and Adult Headform Test
Areas that must comply with the HIC1000 limit must be at least two-
thirds of the numerical value of the Hood Area. Because hard areas
under the hood are challenging to mitigate, for practicability reasons
the HIC limit for the remaining test areas is higher, but nonetheless
limited to HIC1700.\21\
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\19\ Injuries can be categorized according to the Abbreviated
Injury Scale (AIS). AIS ranks individual injuries on a scale of 1 to
6: 1=minor, 2=moderate, 3=serious, 4=severe, 5=critical, and
6=maximum (untreatable). In previous rulemakings (notably with
respect to those involving FMVSS No. 208 and FMVSS No. 214), NHTSA
associated HIC1000 with an 11% risk of AIS 4+ brain injuries.
\20\ FMVSS No. 228 would have detailed procedures that define
the areas on the hood, including a Wrap Around Distance (WAD)
procedure that identifies various reference lines on the hood. As
explained in a later section, in any particular vehicle vertical
longitudinal plane, the Wrap Around Distance is the distance from a
point on the ground directly below the vehicle's most forward edge
in that plane, to a designated point on the hood, as measured with a
flexible measuring device, such as a flexible wire. WADs of various
lengths correlate to where pedestrians of different heights would
hit their head on the hood when struck from the side. We can create
a WAD line using wires of different lengths, e.g., a wire of 1700 +/
- 1 mm can be used to draw a line at 1,700 mm from the ground
reference plane (such a line is referred to as WAD1700).
\21\ HIC1700 is associated with a 36% risk of AIS 4+ brain
injuries.
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To meet the HIC limits, hoods would be required to have protective
countermeasures that attenuate the energy of the impact during initial
contact of the headform, and/or that provide sufficient clearance (open
areas) to prevent the headform from bottoming out on objects beneath
the hood. The countermeasures would have to ensure that the hood is not
too stiff (such a hood would fail the HIC requirement) and not too soft
(a too soft hood could also fail because the headform could penetrate
down to the level of a hard, immovable structure beneath the hood).
Among other objectives, an effective design balances hood stiffness
with depth of penetration.\22\
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\22\ Examples of elements of designs that are beneficial to
pedestrian head protection are: introducing additional clearance
between the inner and outer skins of the hood, using energy-
absorbing materials to improve shock absorption, redesigning stiff
structures under the hood, such as hinges and headlight frames, to
crush, collapse, or shear off, and redesigning the side edges of the
hood where it meets up with the fenders to use a more deformable
support structure or moving the stiff hood-to-fender junction out of
the head impact zone. ``Active hoods'' have also emerged that have a
front-end sensor and lever arms to automatically lift (pop up) the
hood upon detecting that a pedestrian has been struck. An actuator
near the hinge pops the hood slightly to provide more space between
the hood and rigid components in the engine bay.
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B. Potential Impacts of the Rulemaking

FMVSS No. 228 would apply to passenger cars and to MPVs, trucks,
and buses with a GVWR of 4,536 kg (10,000 lb) or less.\23\ Due to the
widespread adoption and use of GTR 9 by other countries, most passenger
vehicles sold in the U.S. that use international platforms already
incorporate the head protection designs of the GTR. Regardless of
current voluntary conformance, we propose to adopt GTR 9 into an FMVSS
to ensure future vehicles provide at least the pedestrian head
protections voluntarily provided today. We also seek to address the
many U.S. variants and other models built upon uniquely American
platforms that may or may not be designed to the GTR requirements. This
includes essentially the entire pickup truck and large SUV segments
(about 22% of the U.S. passenger vehicle 2020 sales, according to data
provided by Wards Automotive). Our testing indicates that it is
possible for some pickup trucks to pass the headform HIC
requirements,\24\ which implies domestic implementation is feasible.
This proposal would ensure that uniquely American platforms, such as
pickups, would provide the proposed level of pedestrian head
protection. In this NPRM, NHTSA also considers modifying some aspects
of GTR 9 to clarify the wording of the regulation, improve objectivity,
and potentially increase safety benefits resulting from the GTR's
application to the U.S. fleet. NHTSA proposes a domestic FMVSS No. 228
to achieve those enhancements.
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\23\ Consistent with the GTR, the proposed regulatory text
includes a provision that excludes from the standard MPVs, trucks,
and buses where the distance, measured longitudinally on a
horizontal plane, between the transverse centerline of the front
axle and the seating reference point of the driver's seat, is less
than 1000 mm. However, we are considering applying FMVSS No. 228 to
these vehicles and are requesting comment on this issue later in the
preamble.
\24\ In headform testing of mid-2000 model year vehicles, large
SUVs and pickups performed about the same as minivans, smaller SUVs,
and passenger cars. For more details, see Mallory et al., (2007),
Pedestrian GTR testing of current vehicles, ESV Paper No. Paper No.
07-0313. Among the vehicles tested were two pickups--a 2003 Dodge
Ram and a 2005 Chevy Silverado--and neither had a head impact that
exceeded the HIC limit in this NPRM.
---------------------------------------------------------------------------

This NPRM is economically significant under Executive Order 12866
due to the benefits estimated to result from the proposed standard.
NHTSA's PRIA analyzes the potential impacts of proposed FMVSS No. 228.
NHTSA has placed a copy of the PRIA in the docket for this NPRM.\25\
---------------------------------------------------------------------------

\25\ The PRIA may be obtained by downloading it or by contacting
Docket Management at the address or telephone number provided at the
beginning of this document.
---------------------------------------------------------------------------

NHTSA estimates that the proposal would mitigate approximately 67.4
fatalities annually, even after accounting for the effect of PAEB.
(However, as explained in detail in sections below, the count of
injuries will increase as averted fatalities are replaced by injuries.)
For passenger cars, the cost per vehicle is estimated to be in the
range of $2.86-$3.50 when discounted at 3% and 7%. Similarly, LTVs have
a per vehicle cost of $3.29-$4.08. When discounted at 3% and 7%, the
total annual cost ranges from $48.94 to $60.43 million. The overall
discounted equivalent lives saved (ELS) range from approximately 44.46
to 54.87. Taking into account both discount rates, the cost per ELS is
$1.10 million and net benefits range from approximately $480.79 to
$593.33 million. Table I.1 summarizes the cost and benefits for both
discount rates. Additional details of the benefits and costs analysis
can be found in section X.III of this preamble.

Table I.1--Summary of Cost and Benefits
[Millions]
----------------------------------------------------------------------------------------------------------------
Cost per
Discount rate Cost Equivalent equivalent Monetized Net benefits
lives saved live saved benefits
----------------------------------------------------------------------------------------------------------------
3%.............................. $60.43 54.87 $1.10 $653.76 $593.33
7%.............................. 48.94 44.46 1.10 529.74 480.79
----------------------------------------------------------------------------------------------------------------

[[Page 76927]]

II. Safety Need

In 2020, 38,824 people died on U.S. roads. Of this number, 25,536
were passenger vehicle occupant fatalities, a decrease from 32,225 in
2000.\26\ This reduction is notable, particularly in light of the fact
that the total number of vehicle miles traveled (VMT) in the U.S. has
increased over time. However, during that same timeframe, pedestrian
fatalities increased by 33 percent, from 4,739 in 2000 to 6,516 in
2020.^{27 28}
---------------------------------------------------------------------------

\26\ Traffic Safety Facts 2020 ``A Compilation of Motor Vehicle
Crash Data.'' U.S. Department of Transportation. National Highway
Traffic Safety Administration.
\27\ Traffic Safety Facts 2000 ``A Compilation of Motor Vehicle
Crash Data from the Fatality Analysis Reporting System and the
General Estimates System.'' U.S. Department of Transportation.
National Highway Traffic Safety Administration.
\28\ National Center for Statistics and Analysis. (2021,
October), Early Estimate of Motor Vehicle Traffic Fatalities for the
First Half (January-June) of 2021. (Traffic Safety Facts. Report No.
DOT HS 813 199), Washington, DC: National Highway Traffic Safety
Administration.
---------------------------------------------------------------------------

The vast majority of pedestrian fatalities (98% or 6,132) are due
to a single striking vehicle.\29\ A 2019 NHTSA report analyzed the
critical events or actions related to crashes (e.g., control loss, road
departure), including the critical event of striking a pedestrian.\30\
The report found that an average of 3,731 fatal crashes and a total of
70,461 crashes each year included the critical event of a vehicle
striking a pedestrian (years 2011-2015). This represents 53 fatal
crashes per thousand crashes, the highest among any critical events
tabulated.
---------------------------------------------------------------------------

\29\ NHTSA Fatality Analysis Reporting System (FARS).
\30\ Swanson, E., Foderaro, F., Yanagisawa, M., Najm, W.G., &
Azeredo, P. (2019, August). Statistics of light-vehicle pre-crash
scenarios based on 2011-2015 national crash data (Report No. DOT HS
812 745). Washington, DC: National Highway Traffic Safety
Administration.
---------------------------------------------------------------------------

Most injuries resulting from collisions between vehicles and
pedestrians are inflicted by the frontal structures of vehicles, the
majority of which occur when vehicle travel speeds are lower than 40
km/h (25 mph) (see figure V.2). Pedestrians sustaining life-threatening
injuries typically have head and thorax injuries caused by contact with
the vehicle. A NHTSA study using both U.S. and German crash data found
that the head and lower extremities are the most common injury
locations on a struck pedestrian.\31\ The head, legs, and thorax are
the most common locations for serious injury, and the head, legs, and
pelvis/hip are the most common locations for disabling injuries. A
NHTSA study analyzing the potential effect of the head, upper leg and
lower leg component test procedures estimated that among serious to
fatal injury cases (MAIS \32\ 3+), 37.8 percent of the total expected
potential effects of the test procedures was associated with the
headform test, 24.6 percent was associated with the upper legform test
and 37.6 percent was associated with the lower legform test. When the
analysis was limited to more severe injuries (MAIS 4+ or fatal cases),
the influence of the headform test was substantially higher, while the
relative influence of the upper legform and lower legform tests was
reduced.\33\
---------------------------------------------------------------------------

\31\ Mallory, A., Fredriksson, R., Rosen, E., Donnelly, B.
(2012, October). Pedestrian Injuries By Source: Serious and
Disabling Injuries in US and European Cases. 56th AAAM Annual
Conference.
\32\ MAIS stands for Maximum Abbreviated Injury Scale.
\33\ Mallory, A., Yarnell, B., Kender, A., & Stammen, J. (2019,
May). Relative frequency of U.S. pedestrian injuries associated with
risk measured in component-level pedestrian tests (Re-port No. DOT
HS 812 658). Washington, DC: National Highway Traffic Safety
Administration.
---------------------------------------------------------------------------

Studies have found a high prevalence of five crash types in
collisions between vehicles and pedestrians.\34\ These crash types are:
---------------------------------------------------------------------------

\34\ Snyder and Knoblauch (1971); Hunter WW et al. (1995),
Pedestrian and Bicycle Crash Types; DaSilva MP et al., (2003),
Analysis of Pedestrian Crashes, Report No. DOT HS 809 585, April
2003, Washington DC, NHTSA; Thomas L et al. (2014), North Carolina
pedestrian crash types, 2008-2012, University of North Carolina
Highway Safety Research Center, March 2014.
---------------------------------------------------------------------------

Dart-out (first half)--where the pedestrian appears
suddenly midblock, often from between parked cars, presents a limited
exposure time to the driver and is struck less than halfway across the
roadway.
Dart-out (second half)--similar to the Dart-out (first
half) except the pedestrian is struck after crossing half or more of
the roadway.
Intersection dash--where the pedestrian presents a short
time exposure to the driver at an intersection either because the
pedestrian runs across the intersection, is blocked from view, or
crosses unexpectedly.
Multiple threat--where a vehicle stops for a crossing
pedestrian and, in so doing, blocks the pedestrian from the view of the
driver in a second car that is overtaking the first car (includes
intersection and midblock situations).
Vehicle turn/merge--where the driver is concentrating on
turning into or merging with traffic and does not see the pedestrian.
New Federal Motor Vehicle Safety Standard No. 228, Pedestrian head
protection, (FMVSS No. 228) has proposed test procedures designed to
replicate head-to-hood contact in the crash sequences described above.
The procedures replicate a child or adult pedestrian crossing a street
and being struck from the side by a vehicle travelling at a speed
approaching 40 km/h (25 mph).
FMVSS No. 228 would affect vehicles involved in the majority of
fatal pedestrian crashes: passenger cars, light trucks (pickups), and
MPVs (vans, crossover vehicles and SUVs) (see table II.1). Sales are
trending toward more non-passenger cars. Light trucks and MPVs as a
percentage of light vehicle sales have steadily increased from 52% in
2011 to 77% in 2020.\35\
---------------------------------------------------------------------------

\35\ Wards Automotive.
---------------------------------------------------------------------------

In a pedestrian crash, the vehicle striking the pedestrian is
usually the only vehicle involved; the vast majority are single vehicle
collisions in which the vehicle-to-pedestrian collision is the only
harmful event. For fatalities, of front end striking vehicle types,
there is about an even split between passenger cars (43 percent) and
light trucks and MPVs (42 percent). Large trucks (GVWR greater than
4,536 kg (10,000 lb)), which are not covered by this proposal, are
responsible for 6 percent of fatal front end to pedestrian strikes.
Buses (covered by this NPRM only if they have a GVWR of 4,536 kg
(10,000 pounds) or less) are responsible for 0.5 percent of fatal
strikes and the remaining fatal strikes (8 percent) are caused by
unknown vehicle types. The percentages for non-fatal injuries show a
different distribution, with passenger cars representing 58 percent of
front end striking vehicles and light trucks representing 40 percent.

[[Page 76928]]

Table II.1--Pedestrian Injuries and Fatalities in Single Vehicle Front End Crashes by Vehicle Type, 2020
----------------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------------
Class of vehicle Injuries
Fatalities
----------------------------------------------------------------------------------------------------------------
Passenger car................................... 23,158 (58%) 38,961 (98%) 1,972 (43%) 3,941 (85%)
Light Truck and MPV............................. 15,803 (40%) 1,969 (42%)
---------------------------------------------------------------
Large Truck.....................................
274 (6%)
Bus.............................................
21 (0.5%)
Unknown/other................................... 959 (2%)
386 (8%)
Totals (front end).............................. 39,921 (100%)
4,622 (100%)
Totals (all impact locations)................... 50,397
5,536
----------------------------------------------------------------------------------------------------------------
Sources: NHTSA's Fatal Accident Reporting System (FARS) and National Automotive Sampling System--General
Estimates System (GES). NHTSA's Traffic Safety Facts Sheet.

In 2020, of all motor-vehicle related fatalities and injuries
(including drivers, passengers, pedestrians, etc.) pedestrians
accounted for 16 percent of all fatalities and 4 percent of injuries in
the under 16 age group; pedestrians accounted for 12 percent of all
motor vehicle-related fatalities and 2 percent of injuries in the age
group 16-34; and pedestrians accounted for 19 percent of fatalities and
3 percent of injuries in the age group 35-44. For the age groups of 45-
64 and 65 and older, the fatality figures were 21 percent and 18
percent, respectively. Injuries for these two groups were both 3
percent.

Table II.2--Pedestrians as a Percentage of All Traffic Fatalities and
Injuries in 2020 by Age Group
------------------------------------------------------------------------
Percent of traffic Percent of traffic
Years old fatalities injuries
------------------------------------------------------------------------
15 and Under.................. 16 4
16-34......................... 12 2
35-44......................... 19 3
45-64......................... 21 3
65 and Over................... 18 3
------------------------------------------------------------------------
Sources: FARS and GES.

This proposal addresses the injuries and fatalities resulting from
head impacts to the front of the vehicle. The derivation of the target
population is described in detail in the PRIA accompanying this
proposal. A summary of the PRIA is contained in section XIII of this
proposal.

III. Foundations for the Proposal

NHTSA protects pedestrians through rulemaking, consumer information
provided by the agency's New Car Assessment Program, safety research,
and public education programs to improve safe driving and walking
practices.\36\ With respect to rulemaking, a number of vehicle
standards have been issued for pedestrian safety, such as FMVSS No. 111
(49 CFR 571.111), which has rear visibility requirements that
manufacturers must meet through backup cameras, and which requires
outside rearview mirrors and their mountings to be free of sharp points
or edges that could injure pedestrians. FMVSS No. 131 (49 CFR 571.131)
applies to school bus stop arms that control traffic around children
boarding or unloading from school buses. NHTSA recently amended FMVSS
No. 108 (49 CFR 571.108) to permit the installation of adaptive driving
beam requirements that help to improve roadway illumination so drivers
can more easily detect pedestrians and motorcyclists.\37\ NHTSA
additionally expects that FMVSS No. 127, recently published final rule
requiring PAEB, would have substantial benefits in preventing
collisions with pedestrians and reducing the speed of impacts.
---------------------------------------------------------------------------

\36\ https://www.nhtsa.gov/road-safety/pedestrian-safety.
\37\ 87 FR 9916; February 22, 2022.
---------------------------------------------------------------------------

NHTSA's Efforts on a Pedestrian Head Protection Standard

Over many years, NHTSA has studied the feasibility of additional
countermeasures to reduce the severity of pedestrian leg, upper body,
and head injuries. In 1981, NHTSA issued an NPRM \38\ to limit the
amount of force that may be exerted by a striking vehicle's bumper area
on an adult pedestrian's lower leg in a 32.2 km/h (20 mph) crash. The
rulemaking was later terminated when the potential countermeasure (a
softer bumper) did not prove practicable.\39\ A decade later, NHTSA had
plans for an NPRM for head impact protection but discontinued
regulatory work in that area at that time.\40\
---------------------------------------------------------------------------

\38\ 46 FR 7015; January 22, 1981.
\39\ 69 FR 14496, April 10, 1991.
\40\ NHTSA held a public meeting on August 20, 1991, to seek
public input on the agency's plans for a pedestrian protection
regulation. Only the hood requirements were discussed at this
meeting. In response to NHTSA's pedestrian safety plan presented at
the meeting, all motor vehicle manufacturers indicated at least some
major redesign would be required to meet the headform requirements.
Based on such comments, unknowns about the benefits projected, the
high costs of major vehicle redesign, and several other factors
(such as international harmonization, pedestrian behavior
enforcement, better infrastructure, and other crash avoidance
measures), the agency did not proceed with the head impact
protection rulemaking.
---------------------------------------------------------------------------

NHTSA, however, continued its research into child and adult
pedestrian protection. The agency collaborated closely with other
countries to harmonize international procedures and requirements,\41\
and carried out key pedestrian research and data collection with
international stakeholders such as the International Organization for
Standards (ISO),\42\ the International Harmonization of Research
Activities (IHRA),\43\ the European Commission

[[Page 76929]]

(E.C.), and the European Enhanced Vehicle Safety Committee (EEVC).\44\
NHTSA was a key contributor to the development of Global Technical
Regulation No. 9 (GTR 9) for pedestrian protection. This NPRM proposes
to incorporate GTR 9 into a new FMVSS No. 228, to include pedestrian
crashworthiness head protection requirements in the FMVSS for the first
time.
---------------------------------------------------------------------------

\41\ 61 FR 58362, November 14, 1996.
\42\ ISO is a worldwide standards-setting organization to
facilitate the international exchange of goods and services.
\43\ IHRA was an inter-governmental steering committee formed to
facilitate multi-national collaboration in research in major problem
areas of road safety, including pedestrian safety. The IHRA expert
group on pedestrian safety developed test procedures to assess the
vehicle-to-pedestrian collision.
\44\ The EEVC does not set standards or enforce regulations and
is not a part of the European Commission (E.C.). The EEVC can only
recommend safety standards to the E.C. and other legislative states,
which may or may not develop them into regulations. The EEVC carries
out auto safety research in a number of specialized areas called
``Working Groups.'' Research within a Working Group, overseen by a
steering committee of representatives from Europe's national
governments, is carried out by nominated technical experts who may
also work for the automotive industry. Funding for EEVC research is
typically provided as ``in-kind'' contributions from the groups
represented by the steering committee members and technical experts.
---------------------------------------------------------------------------

IV. The Global Technical Regulation

A. Introduction

On June 25, 1998, the U.S. became the first signatory to the
``Agreement Concerning the Establishing of Global Technical Regulations
for Wheeled Vehicles, Equipment and Parts which can be Fitted and/or be
Used on Wheeled Vehicles,'' commonly referred to as the 1998
Agreement.\45\ The 1998 Agreement was negotiated under the auspices of
the United Nations Economic Commission for Europe (UNECE) under the
leadership of the U.S., the European Community (EC) and Japan. The 1998
Agreement provides for the establishment of global technical
regulations (GTRs) regarding the safety, emissions, energy conservation
and theft prevention of wheeled vehicles, equipment and parts.
---------------------------------------------------------------------------

\45\ The 1998 Agreement is administered by the UN Economic
Commission for Europe's World Forum for the Harmonization of Vehicle
Regulations (WP.29). https://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29glob/globale.pdf. The 1998 Agreement
entered into force on August 25, 2000.
---------------------------------------------------------------------------

By establishing GTRs under the 1998 Agreement, governmental
organizations (Contracting Parties) seek to harmonize motor vehicle
regulations at the regional and national levels.\46\ Under the 1998
Agreement, Contracting Parties voting in favor of establishing a GTR
are obligated to ``submit the technical Regulation to the process''
used in the country to adopt the requirement into the agency's law or
regulation.\47\ In the United States, that process usually commences
with an NPRM, Advance NPRM (ANPRM), or Request for Comment. Under the
terms of the 1998 Agreement, contracting parties are not obligated to
adopt the GTR after initiating this process.\48\ The 1998 Agreement
recognizes that governments should have the authority to determine
whether the GTR meets their safety needs.
---------------------------------------------------------------------------

\46\ Non-governmental organizations may also participate in a
consultative capacity in groups developing GTRs. Manufacturers may
participate through non-governmental organizations representing
industry. Individual manufacturers may also provide input to the
process.
\47\ Article 7, 1998 Agreement.
\48\ Id.
---------------------------------------------------------------------------

In deciding whether to adopt a GTR as an FMVSS, NHTSA follows the
applicable procedural and substantive requirements for rulemaking,
including the Administrative Procedure Act, the National Traffic and
Motor Vehicle Safety Act (Safety Act) (49 U.S.C. 301), Presidential
executive orders, and DOT and NHTSA policies, procedures and
regulations.\49\ Under Sec. 30111(a) of the Safety Act, Federal Motor
Vehicle Safety Standards must be practicable, meet the need for motor
vehicle safety, and be stated in objective terms.\50\ Section 30111(b)
states that, when prescribing such standards, NHTSA (by delegation at
49 CFR 1.95) must, among other things, consider all relevant, available
motor vehicle safety information, consider whether a standard is
reasonable, practicable, and appropriate for the types of motor
vehicles or motor vehicle equipment for which it is prescribed, and
consider the extent to which the standard will further the statutory
purpose of reducing traffic crashes and associated deaths and injuries.
---------------------------------------------------------------------------

\49\ NHTSA's policies in implementing the 1998 Agreement are
published in 49 CFR part 553, appendix C, ``Statement of Policy:
Implementation of the United Nations/Economic Commission for Europe
(UNECE) 1998 Agreement on Global Technical Regulations--Agency
Policy Goals and Public Participation.'' NHTSA's paramount policy
goal under the 1998 Agreement is to ``[c]ontinuously improve safety
and seek high levels of safety, particularly by developing and
adopting new global technical regulations reflecting consideration
of current and anticipated technology and safety problems.'' Id.
\50\ ``Motor vehicle safety'' is defined in the Safety Act as
``the performance of a motor vehicle or motor vehicle equipment in a
way that protects the public against unreasonable risk of accidents
occurring because of the design, construction, or performance of a
motor vehicle, and against unreasonable risk of death or injury in
an accident, and includes nonoperational safety of a motor
vehicle.'' 49 U.S.C. 30102(a)(9).
---------------------------------------------------------------------------

B. GTR 9

In developing GTR 9, NHTSA collaborated with experts from
contracting parties to the 1998 Agreement,\51\ particularly the
European Union (technical sponsor of the GTR \52\) and Japan. This NPRM
begins the process of adopting the GTR as a NHTSA standard through
rulemaking.
---------------------------------------------------------------------------

\51\ The 1998 Agreement entered into force in 2000 and is
administered by the UN Economic Commission for Europe's World Forum
for the Harmonization of Vehicle Regulations (WP.29). https://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29glob/globale.pdf.
\52\ https://unece.org/fileadmin/DAM/trans/doc/2004/wp29/TRANS-WP29-AC3-07e.pdf.
---------------------------------------------------------------------------

A number of countries have implemented GTR 9.\53\ Even before GTR 9
was established, Europe and Japan had similar pedestrian protection
regulations in place. After GTR 9 was established, WP.29 adopted it as
a full UNECE regulation for all nations under the 1958 Agreement
(Regulation No. 127--Pedestrian Safety Performance).\54\ In recent
years, U.S. variants share similar global designs as vehicles currently
sold in the E.U. that attain the levels of head protection described in
GTR 9. However, as discussed later, interpretation of certain GTR 9
provisions have varied when implemented into national regulations.
---------------------------------------------------------------------------

\53\ GTR 9 has been amended several times, but the U.S. has not
been a signatory to any of the amendments or corrigenda. Thus, in
general, this NPRM focuses on the original GTR and not later
amendments. The first amendment was related to the applicability of
vehicles with short hood areas and increased the number of vehicles
excluded from the requirements of GTR 9. We discuss this provision
and exclusion in section V.B. of this NPRM. At the same time, a
corrigendum was accepted that clarified that the HIC areas may be
broken up into pieces and need not be continuous. This is a concept
that NHTSA had assumed was part of the GTR; this NPRM explicitly
incorporates this concept in the proposed regulatory text (see also
section VII.B of this NPRM). Finally, the GTR was amended to replace
the leg impactor with a more advanced tool. This amendment relates
to provisions that are outside of the scope of this NPRM. https://unece.org/transport/standards/transport/vehicle-regulations-wp29/global-technical-regulations-gtrs.
\54\ The U.S. is not a party to the 1958 Agreement. A
contracting party to the 1958 Agreement can choose which
regulation(s) it wants to adopt, but the regulations in the 1958
Agreement must be adopted ``as is.'' They do not contain different
stringency levels. Also, the 1958 Agreement provides for reciprocal
recognition of type approvals among Contracting Parties. This means
that a vehicle type that has been type approved by one Contracting
Party must be accepted by other 1958 Agreement Contracting Parties.
---------------------------------------------------------------------------

GTR 9 has two sets of performance requirements: (a) for the hood
top and fenders tested by a headform impact; and (b) for the vehicle
front-end area (encompassing the bumper and grille) tested by a legform
impact. Vehicle hoods conforming to the GTR's specifications mitigate
child and adult pedestrian head injury, and bumpers and grilles
conforming to the GTR reduce the risk of adult leg injury. This NPRM
proposes to implement the GTR's provisions for the hood top and
fenders. The May 6, 2023, NCAP RFC proposed to amend NHTSA's NCAP
program to

[[Page 76930]]

include Euro NCAP-based provisions for the hood, bumper, and grille.
Those head, bumper, and grille Euro NCAP provisions correspond closely
to GTR 9.\55\ NHTSA is considering comments to the NCAP RFC in deciding
whether and how to proceed with GTR 9's leg protection requirements in
an FMVSS.
---------------------------------------------------------------------------

\55\ Test procedures very similar to GTR 9 have been
incorporated into many countries' consumer information programs. In
addition to Euro NCAP, Japan's J-NCAP program rates vehicles on
pedestrian safety, using a headform test, as do the Korean KNCAP and
Australasian ANCAP programs.
---------------------------------------------------------------------------

This rulemaking initiates the process of adopting GTR 9 into the
Federal safety standards. This NPRM proposes to implement the head
protection requirements of GTR 9 as FMVSS No. 228. The proposed
standard modifies some of the GTR's provisions to address the
regulatory framework and needs unique to the United States. From years
of researching pedestrian head protection using the procedures
described in the GTR and applying the procedures to the front-end
designs of today, NHTSA has seen instances where the GTR is silent or
unclear about its application to some aspects of hood design. Because
clarity is needed for the FMVSS, NHTSA has addressed these areas with
detailed procedures and criteria in this NPRM that, by design, are
consistent with the GTR and with NHTSA's Safety Act provisions. NHTSA
has incorporated these clarifications into proposed FMVSS No. 228 so
that the standard's procedures are objective and repeatable and meet
the need for safety, in accordance with Safety Act requirements. As
discussed throughout this document, this NPRM also focuses readers on
other ways NHTSA is considering modifying the GTR test procedures for
clarity or to push more safety benefits from the U.S. fleet. An example
of the latter is NHTSA's consideration of narrowing the border
surrounding a test area so that more of the vehicle's hood and fender
area would have to meet the HIC requirements.

C. Further Observations About the Differences Between This NPRM and the
GTR

In drafting FMVSS No. 228, NHTSA's goal has been to produce a
proposal that is true to the agency's understanding of GTR 9 and to the
technical best practices provided by the GTR, so as to ``fully meet the
need in the U.S. for vehicle safety.'' \56\ We believe we have achieved
this with this NPRM, but at times we have found challenges in relating
the original GTR 9 language to the specificity necessary for the self-
certification framework of the Safety Act. The Safety Act requires the
FMVSS to be practicable, meet the need for motor vehicle safety, and be
stated in objective terms. Additionally, the Safety Act requires that
NHTSA consider specific factors in prescribing an FMVSS.\57\ Given
these requirements and considerations, in some instances we have found
the need to define terms and describe test procedures in a more precise
way than GTR 9, but in a way that would add to the objectivity and
clarity of the safety standard.
---------------------------------------------------------------------------

\56\ Section I.B.1, 49 CFR part 553, appendix C, ``Statement of
Policy: Implementation of the United Nations/Economic Commission for
Europe (UN/ECE) 1998 Agreement of Global Technical Regulations--
Agency Policy Goals and Public Participation,'' supra.
\57\ 49 U.S.C. 30111(a) and (b).
---------------------------------------------------------------------------

NHTSA has also shaped this proposal to provide the minimum level of
safety required to address the needs we face in this country. NHTSA is
aware that other countries have implemented the regulation in some ways
that differ from our reading of the regulation in ways that reduce the
safety minimum even further. For example, this NPRM adds clarification
regarding how the agency will determine the amount of testable hood
area that must meet a head injury criterion (HIC) of 1000 or less,
compared to a HIC of 1700 or less. This is described more fully in
section VI.A of this preamble. UNECE Reg. No. 127 has implemented the
GTR 9 in a way that produces a smaller area that must comply with
HIC1000 than that which results from the GTR as NHTSA understands it,
or as NHTSA proposes in this NPRM to address the growing pedestrian
safety needs in this country. In section VIII of this preamble, we
provide a detailed discussion of a proposed amendment to GTR 9 that
NHTSA has not supported because of its potential to reduce the area
subject to headform testing. NHTSA discusses throughout this preamble
the differences between this proposed FMVSS No. 228 and the current GTR
9, and the reasons for those differences.\58\ Finally, NHTSA seeks to
design FMVSS No. 228 to address pedestrian safety needs particular to
the U.S. The regulatory text in this NPRM reflects the wording of the
GTR. At the end of various sections, however (see, e.g., section
VI.C.1), the preamble describes and requests comment on specific ways
NHTSA may change the regulatory text in this rulemaking to better
address this country's pedestrian safety needs.
---------------------------------------------------------------------------

\58\ In advance of the publication of this NPRM, NHTSA received
a July 7, 2022 letter from the Alliance for Automotive Innovation
restating support of the interpretation of the GTR 9 that aligns
with the proposed GTR amendment. On December 9, 2022, NHTSA met with
the Alliance of Automotive Innovation at their request, to discuss
the contents of their letter to NHTSA. The letter can be found in
the docket, along with a list of other contacts since April 2022.
The agency's position and rationale are fully explained in this
preamble, particularly in section VIII.B.
---------------------------------------------------------------------------

V. Approach of the Proposed Standard

A. Overview

FMVSS No. 228 would prohibit vehicles from exceeding a certain HIC
level when subjected to testing simulating a head-to-hood impact. The
standard is designed to provide head protection to a walking child and
a walking adult when side-struck. This posture was chosen because it
represents one of the most common interactions between vehicles and
pedestrians. The side-struck posture is also regarded as ``worst
case.'' \59\ Hoods would have to safely absorb and manage the energy of
the striking pedestrian's head.
---------------------------------------------------------------------------

\59\ Soni A, Rober T, Beillas P (2013), Effects of Pedestrian
Pre[hyphen]Crash Reactions on Crash Outcomes during Multi-body
Simulations, 2013 IRCOBI Conference, Paper No. IRC-13-92.
---------------------------------------------------------------------------

The proposed standard defines each hood as having two distinct
areas: one where a struck child pedestrian's head would impact (Child
Headform Test Area) and one where an adult pedestrian's head would
impact (Adult Headform Test Area), both in a 40 km/h (25 mph) vehicle
impact. The proposed performance requirements are based on HIC as
computed from the acceleration of the headform upon impact. FMVSS No.
228 would limit HIC when tested with the headforms.
The location of a pedestrian's head impact on the hood is dependent
on several variables, including the speed of the vehicle impact, the
vehicle front-end shape, and the height of the pedestrian. Proposed
FMVSS No. 228 is designed so that vehicle countermeasures to meet the
HIC limits would benefit pedestrians of all sizes. In section VI of
this preamble, we explain in detail the specific areas of the hood that
would be regulated under the proposal, as well as considerations for
expanding this area.
Proposed FMVSS No. 228 includes detailed procedures that define
reference lines on the vehicle from which NHTSA would calculate the
area of the vehicle that must provide pedestrian head protection.
Proposed FMVSS No. 228's wrap around distance (WAD) procedure is a
simple procedure used in several sections of GTR 9 to identify various
reference lines on the hood. Reference lines that run laterally across
the hood are drawn relative to a specified WAD. Those lines are
referred to herein as WAD lines. NHTSA helped develop the WAD procedure
for

[[Page 76931]]

pedestrian protection test programs internationally.
The WAD is the distance from a point on the ground directly below
the bumper's most forward edge, at a specific lateral location, to a
designated point on the hood, as measured with a flexible measuring
device, such as a non-stretch flexible wire. During measurement of the
WAD, the device (the non-stretch flexible wire) is held taut, to
measure distances while being held in a vertical longitudinal (x-z)
vehicle plane. A WAD of a specified distance can identify a point on
the vehicle's hood. A WAD line can be drawn on a vehicle by connecting
the end points of the wire as it traverses across the front of the
vehicle. We can create a WAD line using wires of different lengths,
e.g., a wire of 1000 1 mm can be used to draw a line at
1,000 mm from the ground reference plane (such line is referred to as
``WAD1000'' in this NPRM), 1700 1 mm (``WAD1700'') and
2100 1 mm (``WAD2100'').\60\ See figure V.1, below,
illustrating how WAD is measured.
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\60\ The naming convention is to follow ``WAD'' with the length
of the wire used for the measurement, and to refer to WAD [wire
length] to refer to the line drawn by using the wire and the WAD
procedure.
---------------------------------------------------------------------------

A WAD line can be objectively determined and is a good indicator of
where head impacts are likely to occur on any particular hood.\61\ The
WAD measurement accounts for both pedestrian height and vehicle front-
end configuration. That is, in a 40 km/h crash, a given pedestrian's
head-to-hood contact point is approximated by the WAD that corresponds
to the pedestrian's standing height.
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\61\ Paragraph 71 of the ``Safety Need'' section of GTR 9.
https://unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29registry/ECE-TRANS-180a9e.pdf.
[GRAPHIC] [TIFF OMITTED] TP19SE24.003

Key Elements of the Proposal
The proposed standard has certain key elements to replicate the
real-world 40 km/h (25 mph) impact in an objective and enforceable
manner. The key elements are:
Relevance to the vehicles involved in pedestrian crashes
at 40 km/h (25 mph);
A methodology incorporating component testing of the hood
using headforms representing child and adult pedestrians;
Performance requirements based on HIC as measured by the
headforms;
A hood mark-off procedure to denote test areas; and
Flexibility in performance requirements to address
practicality challenges.
These key elements and others are discussed in detail below.

B. Relevance to the Involved Vehicles

FMVSS No. 228 would apply to passenger cars, and to MPVs, trucks,
and buses with a GVWR of 4,536 kg (10,000 lb) or less, except for
vehicles with short front ends (a very short front hood area). Proposed
FMVSS No. 228 would also apply to bidirectional vehicles, i.e.,
vehicles that can be operated in either direction. We discuss these
issues below.
Vehicles With Short Front Ends
Reflecting the text of GTR 9, the NPRM's proposed regulatory text
(S3) excludes MPVs, trucks, and buses where the distance, measured
longitudinally on a horizontal plane, between the transverse centerline
of the front axle and the seating reference point (SgRP) of the
driver's seat, is less than 1,000 mm.\62\ In the statement of technical
rationale for GTR 9, the drafters argued that these vehicles have a
very short hood and a front shape that is very close to vertical, so
the pedestrian kinematics with these vehicles are believed to be very
different than a collision with a vehicle with a longer hood. The
drafters also concluded that there are difficulties in applying the
tests to these vehicles, particularly regarding the determination of
test zone reference lines.
---------------------------------------------------------------------------

\62\ This is dimension L114 in SAE J1100 ``Motor Vehicle
Dimension.'' A later amendment to GTR published in 2011, which was
not signed by the U.S., extended this dimension to 1,100 mm. (ECE/
TRANS/180/Add.9/Amend.1/appendix 1).
---------------------------------------------------------------------------

NHTSA drafted the regulatory text with this exclusion, but NHTSA
requests comments on whether the subject vehicles should be included in
FMVSS No. 228. Notwithstanding the drafters' reasons for excluding the
vehicles from GTR 9, NHTSA believes applying proposed FMVSS No. 228 to
these vehicles may be appropriate given developments since the GTR.
With the advent of new designs in electric vehicles, including designs
of automated vehicles on the road today with very short front ends,
front end designs appear to be evolving to less

[[Page 76932]]

conventional hood designs. The agency is aware of prototype ride-share
automated vehicle platforms, such as the Cruise Origin and Zoox, and of
electric vehicles (EVs) being marketed by Canoo, that have a very short
front hood area or a flat front face.\63\ We are concerned that future
automated and/or electric vehicles may become more prevalent in the
fleet and that they could be excluded from the standard simply because
of this GTR provision.
---------------------------------------------------------------------------

\63\ NHTSA understands that the Cruise Origin and Zoox vehicles
do not have a traditional driver's seating position.
---------------------------------------------------------------------------

In addition, we base our concerns about this exclusion on present
day vehicles and their presence in the U.S. vehicle fleet. The agency
took an available selection of vehicles and measured the horizontal
distance from the front axle to the seat bight (the area close to and
including the intersection of the surfaces of the vehicle seat cushion
and the seat back), with the seat adjusted to the full forward and full
rearward position. The vehicles and resulting dimensions are provided
in table V.1, below. The position of the SgRP for these vehicles was
not readily available, but the distance between the axle and the SgRP
would likely lie somewhere between the range of distances measured to
the seat bight. As stated above, the GTR 9 exclusion would be triggered
if the distance from the front axle to the SgRP is less than 1,000 mm.
The agency found that at least one type of full-size cargo van
(Ford Transit) could possibly qualify for the exclusion. Looking at
both small and full-size cargo and passenger vans, it is clear that
many of them share similar design attributes of a short hood and a
relatively forward seating position with respect to the front
wheels.\64\ This suggests to the agency that the most likely types of
vehicles in the current fleet that would be excluded are small and
large vans. For 2021, this van segment had a sales volume of
approximately 400,000 vehicles, constituting about 2.7% of the 15
million total 2021 sales.^{65 66} Thus, the 2.7% value provides
an upper bound on the number of vehicles likely to meet the exclusion
criteria. It also seems clear to the agency that relatively minor
changes in design could place a vehicle in the excluded category. We
are concerned about the effects of the exclusion in reducing the
benefits of this proposal.
---------------------------------------------------------------------------

\64\ Some vehicles in this category would be the Chevrolet
Express, Ford E-Series, Ford Transit, Ford Transit Connect, GMC
Savana, Mercedes-Benz Metris, Mercedes-Benz Sprinter, Nissan NV,
Nissan NV200, Ram ProMaster, Ram ProMaster City.
\65\ https://www.goodcarbadcar.net/2021-us-commercial-van-sales-figures-by-model/.
\66\ https://www.goodcarbadcar.net/2021-us-vehicle-sales-figures-by-model/.
---------------------------------------------------------------------------

NHTSA has tested a vehicle with a short front end similar to
vehicles in the excluded category and has successfully conducted
headform testing. This testing demonstrated that the proposed WAD-based
test procedure can be applied to short front end vehicles. NHTSA also
believes it would be practicable for the vehicles to meet the proposed
standard. NHTSA tested the 2004 GMC Savana van to a slightly modified
version of the GTR 9 test protocol, with a 32 km/h head impact speed.
Three of four hood impacts had a HIC below 600. The fourth test, near
the edge of the hood had a HIC of less than 1000.\67\ These results
suggest that FMVSS No. 228 would be practicable for similar vehicles.
---------------------------------------------------------------------------

\67\ Stammen J, et al, ``Pedestrian Head Safety Survey of U.S.
Vehicles In Support of the Proposed Global Technical Regulation
(GTR)'' (2006). https://unece.org/DAM/trans/doc/2008/wp29/WP29-144-03e.pdf.

Table V.1--Sample of Vehicle's Horizontal Distance From the Front Axle to Seat Bight
----------------------------------------------------------------------------------------------------------------
Approximate distance to seat
bight (mm)
Year Make/model --------------------------------
Full forward Full rearward
----------------------------------------------------------------------------------------------------------------
2015......................................... Ford Transit.................... 930 1180
2016......................................... Honda Fit....................... 1200 1480
2003......................................... Honda Pilot LX.................. 1250 1500
2016......................................... Nissan Rogue.................... 1270 1480
2011......................................... Chevrolet Cruze................. 1300 1550
2012......................................... Ford Focus...................... 1320 1570
2001......................................... Honda Civic..................... 1330 1530
2012......................................... Ford Fusion..................... 1380 1760
2006......................................... Infinity M35.................... 1400 1650
2002......................................... Jeep Wrangler................... 1680 1880
----------------------------------------------------------------------------------------------------------------

We request comments on the practicability concerns related to these
vehicles, specific challenges such vehicles present related to the
proposed test procedure, and what adjustments, if any, would be
available to apply proposed FMVSS No. 228 to such vehicles. We also
request comments on the safety need and outcomes of including all light
vehicles under the proposed standard to maximize potential safety
benefits to pedestrians and other vulnerable road users.
Rear Engine Vehicles and Bidirectional Vehicles
It is the agency's intent to apply FMVSS No. 228 to rear engine
vehicles, as long as they meet the other applicability requirements.
This is because the location of the tested area is not dependent on
where the engine is located, but rather is keyed to the front of the
vehicle. We believe GTR 9 is intended to apply to such vehicles.
A similar assumption cannot be made about whether GTR 9 is intended
to cover bidirectional vehicles. Certainly, there is no explicit
mention of these vehicles. Nonetheless, it is NHTSA's intent to apply
FMVSS No. 228 to bidirectional vehicles. NHTSA believes that such
vehicles may become more common, particularly with the advent of more
automated vehicle platforms, and that there is a safety need to apply
proposed FMVSS No. 228 to the vehicles because they could strike
pedestrians. Therefore, we have explicitly made the definitions and
regulatory text of proposed FMVSS No. 228 neutral concerning the
direction of vehicle operation, i.e., the regulatory text is intended
to work for bidirectional vehicles. First, we have explicitly included
bidirectional vehicles in the

[[Page 76933]]

Applicability section of the proposed regulatory text. Next, we have
defined ``bidirectional'' vehicle to mean a vehicle that is intended to
operate at similar speeds and with similar maneuverability in both
directions of the vehicle longitudinal axis.\68\ Similarly, we have
defined ``front'' to mean the leading portion of the vehicle during
full speed operation. We seek comment on whether the terms accomplish
the agency's objective of including bidirectional vehicles in FMVSS No.
228.
---------------------------------------------------------------------------

\68\ The terms of this definition are intended to distinguish
these vehicles from conventional vehicle that can also operate in
two directions. However, for conventional vehicles the rearward or
backing direction is not intended for full speed operation, but
rather low speed and typically in a single gear.
---------------------------------------------------------------------------

C. Advantages of Headform Component Tests

The NPRM proposes using headform component tests rather than full
vehicle dynamic tests in which a vehicle would strike a pedestrian
dummy. The agency believes that headform component tests have
advantages over full vehicle dynamic tests. The area of the vehicle
hood that could contact a pedestrian's head is large. A set of headform
component tests enables NHTSA to target hood areas that the agency
believes represent danger points, and test with a high degree of
accuracy and repeatability. Like all crashes, every real-world
pedestrian crash is unique in some way. When the range of statures and
other crash variables are taken into account, the area of the vehicle
that could contact the head is so large that currently the only
feasible test method is one that is based on a sub-system test
approach. Proposed FMVSS No. 228 uses such an approach by focusing on
the hood and by making use of a set of headform component tests that
can target the hood area efficiently. The headform mass, impact angle,
and impact speed can all be controlled in a way that will assure that
the standard will provide safety in real world impacts and can be
enforced. The characteristics of the headforms are discussed in detail
later in this preamble.
Pedestrian test dummies have been developed for crashworthiness
research. In general, the repeatability of tests using a pedestrian
dummy is relatively poor because small variations in initial
positioning influence the head-to-hood contact as the dummy passes
through its sequence of movements after being struck by the vehicle.
Moreover, head impact locations are highly dependent on stature and
gait, so use of a single pedestrian dummy for crashworthiness purposes
would make it very difficult to assess hood areas that are likely to be
struck by persons not represented by the dummy.

D. Head Injury Criterion (HIC)

Consistent with GTR 9, NHTSA has determined that HIC is an
appropriate injury criterion for the proposed standard. The proposed
standard would require HIC to be less than 1000 for most hood impacts.
HIC is calculated using the expression below, where the resultant
acceleration, ar, at the headform center of gravity and
specified as a multiple of g (the acceleration of gravity), is
integrated over 15 millisecond ranges covering the entire impact.
[GRAPHIC] [TIFF OMITTED] TP19SE24.004

HIC, which is a function of the tri-axial linear acceleration in
the headform, is well established and used in numerous occupant
protection FMVSS. A HIC value of 1000 represents an 11 percent risk of
a brain injury of severity level AIS 4 or greater and a HIC value of
1700 represents a 36 percent risk.\69\ Many of NHTSA's impact
protection standards use HIC to measure the potential for head injury
and limit HIC to a value of 1000; these include FMVSS No. 201, Occupant
protection in interior impact, FMVSS No. 214, Side impact protection,
and FMVSS No. 222, School bus passenger seating and crash protection.
NHTSA considered other brain injury metrics, such as angular velocity,
but determined that HIC is the best available criterion at this
time.\70\
---------------------------------------------------------------------------

\69\ AIS (Abbreviated Injury Scale) ranks individual injuries by
body region on a scale of 1 to 6: 1=minor, 2=moderate, 3=serious,
4=severe, 5=critical, and 6=maximum (untreatable).
\70\ In an actual vehicle-pedestrian collision, head rotation
that occurs before, during, or after the head impact with the hood
could result in concussive brain injuries. However, the biofidelity
of a headform--unattached to the body--could be compromised in its
ability to generate angular velocity representative of an actual
pedestrian head impact. The agency would like to understand more
about the biofidelity of a headform when used to measure angular
velocity.
---------------------------------------------------------------------------

Proposed FMVSS No. 228 would require vehicles to meet HIC limits
when subjected to hood headform impactor testing. It defines the
forward, rear and side areas of the hood, thus defining a primary
area--the ``Hood Top.'' \71\ From there, a typically smaller ``Hood
Area'' is defined using, among other things, the Wrap Around Distance
lines described earlier. Of this Hood Area, the standard would define a
Child Headform Test Area and an Adult Headform Test Area, excluding
margins at the side and potentially at the front and rear, which would
be tested with the child and adult headforms, respectively. The HIC
must not exceed 1000 (HIC1000) over a certain portion of the Child and
Adult Headform Test Areas, as a percentage of the overall Hood Area.
Specifically, the portion of the Child Headform Test Area that must
meet the HIC1000 provision must be at least one-half of the numerical
value of the Hood Area with a Wrap Around Distance of less than 1,700
mm (WAD1700).\72\ Secondly, the portion of the Combined Child and Adult
Headform Test Areas that must not exceed the HIC1000 provision must be
at least two-thirds of the numerical value of the Hood Area. For
practicability reasons to accommodate a manufacturing need to reinforce
and stiffen the hood edges, the remaining test area is permitted to
have HIC higher than 1000, but nonetheless limited to 1700 for both
headforms.\73\
---------------------------------------------------------------------------

\71\ The procedures for defining these areas are discussed below
in this preamble.
\72\ The drafters of the GTR determined that because the
location of necessary under-hood components cannot be fundamentally
changed, it is unavoidable that they are located in the child
headform test area. Thus, the GTR provides that the relaxation zone
for the child headform test area may be half of the zone (as opposed
to \1/3\ of the zone, as in the adult test area).
\73\ Such reasons include the need to minimize any fluttering of
the hood at high speeds and the ability to slam the hood shut
without deforming the seams at the junction of the hood and fender.
---------------------------------------------------------------------------

HIC time window, 15 ms. Proposed FMVSS No. 228 would reference a 15
millisecond (ms) time window when applying the HIC criterion. For any
15 ms time window, HIC must be below the HIC criterion (e.g., HIC1000).
A 15 ms time window is used in proposed FMVSS No. 208 verses a longer
window

[[Page 76934]]

(e.g., using a 36 ms timeframe) because the FMVSS No. 228 impact is
hard and of short duration. Longer duration impacts may have a greater
HIC when using a 36 ms window (a longer duration impact can occur in
air bag tests when the test dummy's head maintains contact with the air
bag through a crash event). For hard, short duration impacts such as
the headform testing used in proposed FMVSS No. 228, HIC derived from a
15 ms timeframe produces the same numerical value as HIC derived from a
longer window (36 ms). Since the FMVSS No. 228 impact is hard and of
short duration, a 15 ms window is appropriate.
Further, GTR 9 uses a 15 ms window instead of 36 ms to improve the
objectivity of the test. The 15 ms window was viewed as a common-sense
safeguard against signal corruption due to a secondary impact. With
hood impacts, there is a risk that the headform may undergo a secondary
impact in rapid succession (in less than 36 ms), as the head could
strike the hood target then bounce away and land on a structure such as
the windshield, which is outside of the test area. To safeguard against
the effects of a secondary impact, the 15 ms criterion was implemented
as a convenient means to help assure that the HIC value reflects only
that portion of the headform acceleration caused by a hood impact
within the test area. The procedures developed by IHRA, ISO, and the
EEVC all use a 15 ms window to calculate HIC. This criterion and
threshold have been carried over to all subsequent international
standards.
Request for Comment on HIC
We generally agree with the approach and have proposed it
in this NPRM. However, we would like to know more about the following
issues. We have not seen a need to use a 15 ms window, as opposed to a
36 ms window, because head impacts to external car structures are very
short, occurring within a few milliseconds of contact. In practice, 15
ms and 36 ms windows generally have produced the same value in
pedestrian protection tests. Further, in our own testing, we have not
observed an instance where the use of a 36 ms window would have led to
signal corruption due to a secondary impact. We request comment on the
need for a 15 ms timeframe related to testing issues.
We also seek comment on whether a 15 versus 36 ms window
could affect HIC measurements when testing active hoods or cowl air
bags,\74\ features that have appeared in recent years, particularly in
non-U.S. vehicles. We request comments on whether HIC computed in a 36
ms timeframe would be more appropriate and protective against head
injury for vehicles with active hoods or air bag technologies than HIC
computed in a 15 ms window. Should FMVSS No. 228 adopt a HIC 36 ms
timeframe to account for these technologies?
---------------------------------------------------------------------------

\74\ The cowl is the lower edge of the windshield opening.
Active hoods move when a pedestrian impact is sensed, increasing the
distance between the hood and the hard engine components below. A
cowl air bag covers the cowl during a pedestrian impact.
---------------------------------------------------------------------------

E. Speed and Angle at Which the Headforms Would Impact the Hood

The headforms would impact the vehicle hood at specific speeds and
impact angles replicating a real-world 40 km/h (25 mph) impact.
1. Headform Impact Speed
Proposed FMVSS No. 228 would require the launch direction to be
entirely within the plane parallel to the vehicle x-z plane (vertical
longitudinal plane) and the impact speed for both headforms would be 35
km/h (22 mph).\75\ This speed is based on observations of postmortem
human subjects (PMHS) and pedestrian surrogate testing, computer
modeling, and reconstructions of real-world pedestrian collisions. The
proposed velocity of 35 km/h (22 mph) replicates the actual head-to-
hood impact speed of a pedestrian struck by a vehicle traveling at 40
km/h (25 mph).\76\
---------------------------------------------------------------------------

\75\ The vehicle coordinate system used in this NPRM is
consistent with SAE J1100 ``Motor Vehicle Dimension.'' The
coordinate system is as follows: +x direction is the longitudinal
vehicle axis (rearward direction of travel); +y direction is the
lateral vehicle axis (pointing away from the right side of the
vehicle); +z direction is pointing vertically upward.
\76\ Researchers have historically used the ratio of head impact
speed to vehicle speed to characterize the head-to-hood interaction.
A head impact speed of 35 km/h (22 mph) in a 40 km/h (25 mph)
collision yields a ratio of 0.875. Depending on conditions, such as
the shape of the vehicle front-end, the height of the leading edge
of the hood, and the height of the pedestrian, the ratio for an
adult may be as high as 1.4 or as low as 0.7.
---------------------------------------------------------------------------

The proposed test speed encompasses the majority of pedestrian
collisions. About 70 percent of injurious pedestrian collisions occur
at vehicle speeds of 40 km/h (25 mph) or less (see figure V.2, which
averages data from 2011 to 2020).\77\ In addition, the 35 km/h (22 mph)
test speed is a critical part of the real-world event replicated by the
headform impact test. The dynamics of a pedestrian-vehicle interaction
change at a target speed substantially greater than 40 km/h (25 mph).
Above 40 km/h (25 mph), an initial hood-to-torso interaction takes
place where the pedestrian tends to slide along the hood, with the head
overshooting the hood. The head-to-hood interaction that the proposed
test procedure replicates would lose its real-world relevance if a
substantially higher test speed were used.
---------------------------------------------------------------------------

\77\ Mizuno Y, Ishikawa H (2001), Summary of IHRA pedestrian
safety WG activities--proposed test methods to evaluate pedestrian
protection afforded by passenger cars, Paper No. 280, The 17th
International Technical Conference on the Enhanced Safety of
Vehicles, Amsterdam, The Netherlands, June 4-7, 2001.
---------------------------------------------------------------------------

The proposed test speed addresses a safety need within the bounds
of practicability. Although pedestrian fatalities, on average (50%
cumulative value in figure V.2), occur at a collision speed of 70 km/h
(44 mph), the practicability of designing a hood to conform to HIC1000,
based on energy dissipation, appears to become less feasible at a
headform impact speed of 61 km/h (38 mph) (assuming the same ratio of
head speed to vehicle speed used from the proposal, the 61 km/h would
have about 3 times the energy). Moreover, the proposed rule would
reduce the severity of many head injuries that occur at speeds covered
by the test.
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[[Page 76935]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.005

BILLING CODE 4910-59-C
Notwithstanding the proposed headform test speed of 35 km/h (22
mph), NHTSA believes there would be benefits from the proposed standard
for some crashes above a 40 km/h (25 mph) vehicle speed, as the
countermeasures used to meet the proposed HIC thresholds could mitigate
some of the harm resulting from head-to-hood strikes that can occur in
the higher speed crashes. Also, vehicle designs that provide head
protection in a 35 km/h (22 mph) headform impact may also have the
effect of reducing the severity of injuries to body regions other than
the head in collisions at vehicle speeds above 40 km/h (25 mph). For
example, at vehicle to pedestrian collision speeds of 50 km/h (31 mph)
and higher, bi-lateral rib fractures have been observed in thorax-to-
hood contacts.\78\ We request comment on whether some of these types of
injuries could be mitigated by hood designs meeting FMVSS No. 228.
---------------------------------------------------------------------------

\78\ Watanabe A et al (2011), Research of collision speed
dependency of pedestrian head and chest injuries using human FE
model (THUMS version 4), 22nd International Technical Conference on
the Enhanced Safety of Vehicles (ESV), Paper No. 11-0043, Washington
DC, June 2011.
---------------------------------------------------------------------------

NHTSA anticipates PAEB would mitigate 238 fatalities and 2,672
injuries of the current target population for this NPRM and has based
our benefits estimate for this NPRM on that assumption. Automatic
emergency braking helps prevent crashes or reduce their severity by
applying a vehicle's brakes automatically. The systems use on-board
sensors to detect an imminent crash, warn the driver, and apply the
brakes if the driver does not take action quickly enough or increase
the braking application in the case that the driver does not
sufficiently brake to avoid contact. When new vehicles are equipped
with PAEB that meets the requirements specified in FMVSS No. 127, fewer
pedestrians will be struck, which would have the effect of reducing the
target population for this rulemaking. On the other hand, for many
impacts that occur at speeds too high for PAEB to completely mitigate,
PAEB will lower the vehicle's speed so that impact speeds that would
have been greater than 40 km/h (25 mph) could be reduced to close to or
below 40 km/h (25 mph). This would theoretically add to the target
population of this rulemaking because these are pedestrian crashes that
this proposed pedestrian head protection standard could potentially
address. And, as proposed FMVSS No. 228 would ensure the striking
vehicles have protective features that protect against serious to fatal
head injury in these impacts, those pedestrians that would be newly
included in the target population of this NPRM due to PAEB could
arguably be included among those saved from serious to fatal injury by
this head protection rulemaking. However, we have not accounted for the
extent to which the FMVSS No. 127 would add to the target population or
to the population of persons benefiting from this head protection NPRM
because of unknowns about how those benefits could be quantified. As a
result, our analysis likely underestimates benefits. With this in mind,
in the PRIA we estimate that PAEB would decrease the fatality target
population addressed by FMVSS No. 228 by about 4 percent. Comments are
requested on this issue.
NHTSA requests comments on increasing the test velocity
above 35 km/h (22 mph) to capture a greater percentage of pedestrian
impacts presented in the field data and achieve additional safety
benefits.
2. Headform Impact Angle
Consistent with the GTR, NHTSA proposes that, at impact, the
velocity vector of the child headform would form a 50-degree angle down
from the horizontal (50[deg] 2[deg] at the time of
impact). For the adult headform, the

[[Page 76936]]

angle would be 65 degrees (65[deg] 2[deg] at the time of
impact). (See figure V.3, showing the child headform impact and figure
V.4, showing the adult headform impact).
BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TP19SE24.006

BILLING CODE 4910-59-C
The head impact angles were developed based on observations of PMHS
and pedestrian dummy tests, computer modeling, and reconstructions of
real-world pedestrian collisions. The impact angle in a real-world
impact is greater for taller pedestrians than for shorter pedestrians,
and this is reflected in the test procedure. The impact angle in real-
world impacts also varies depending on the shape of the vehicle front-
end, particularly the height of the leading edge of the hood. Passenger
cars (with low leading edges) generally produce head-hood angles that
are closer to 90 degrees than SUVs.
The proposed 65-degree impact angle for the adult headform test is
the same as the IHRA specification. The bulk of research data showed
head impact angles in the range of 50 to 80 degrees; IHRA selected a
nominal headform

[[Page 76937]]

angle of 65 degrees.\79\ Component tests conducted by NHTSA \80\ showed
that HIC sensitivity to impact angle varied with hood stiffness and
proximity to hard understructures. Where there were no hard
understructures, HIC values exhibited very little sensitivity to impact
angle. In general, HIC variation of less than 10 percent was shown
between 50 and 80 degrees.
---------------------------------------------------------------------------

\79\ Because the typical hood is angled forward at about 15
degrees, it causes the 65 degree adult headform impact to create an
80 degree angle of incidence with the hood, i.e., a slightly angled
(non-normal) headform impact.
\80\ Stammen JA, Saul RA, Ko B (2001), Pedestrian head impact
testing and PCDS reconstructions, Paper No. 326, 16th International
Technical Conference on the Enhanced Safety of Vehicles (ESV)
Proceedings, Amsterdam, The Netherlands, June 4-7, 2001.
---------------------------------------------------------------------------

The selection of a 50-degree impact angle for the child headform
test was partly based on computational simulations using a 5th
percentile adult female (which is about the same size as an average 12-
year-old child) \81\ and a 6-year-old child. The simulation results for
the 5th percentile female gave similar average values to those found
for the 50th percentile adult male. For the 6-year-old, however,
simulations showed that the head impact angle was more sensitive to car
shape, particularly to the height of the hood leading edge. An average
value of 45 degrees was found for the 6-year-old. The 50-degree impact
angle is representative of the simulation results with a bias towards
the 6-year-old child.
---------------------------------------------------------------------------

\81\ Janssen and Nieboer, Sub-system tests for assessing
pedestrian protection based on computer simulations, Proceedings of
the IRCOBI Conference, Berlin, September 1991.
---------------------------------------------------------------------------

Request for Comment on the Proposed Impact Angle
We believe that the headform impact test would be the most
stringent when the impact is normal to the hood surface (a 90-degree
angle of incidence to the surface).\82\ If the impact is normal (90
degrees) and there is no glance-off, all of the headform's energy would
have to be absorbed by the hood to stop its downward movement. However,
a 90-degree angle of incidence to the surface may not be consistent
with real world impacts at speeds up to 40 km/h (25 mph) and would
require the impactor launch angle to vary by test location. We request
comment on whether the standard should increase the impact angles to
increase stringency notwithstanding a possible reduction in the
representativeness of real-world crashes.
---------------------------------------------------------------------------

\82\ Assuming that a 15 degree hood angle is typical, a 90
degree head-hood angle would correspond to a 75 degree headform
impact angle from the horizontal.
---------------------------------------------------------------------------

VI. Defining the Relevant Areas Subject to the Standard

Overview: Proposed FMVSS No. 228 would have detailed procedures
that define reference lines on the vehicle from which NHTSA would
calculate the area of the vehicle that must provide pedestrian head
protection. The proposed procedures (including the WAD procedure) are
needed to enable the agency to objectively define the areas on the
vehicle that are subject to the standard, the total HIC1000 area that
must be provided, and the locations of the Child and Adult Headform
Test Areas. The procedures are necessary for NHTSA to assess a test
vehicle's compliance with the standard. NHTSA would use the procedures
to define these relevant areas and would not use manufacturer input to
define them.
As relevant areas are defined in the following section of this
NPRM, any necessary clarification to GTR 9 will be identified and
described. Although the various hood reference lines should be
essentially identical to those in GTR 9, the terminology used to
describe the areas and reference lines are not identical. A more
complete comparison of the terminology used in GTR versus this NPRM can
be found in section VIII.
The areas subject to the standard are the areas likely to be
impacted by the head of a pedestrian and for which countermeasures are
or could reasonably be available. The most severe head injuries can be
due to contact anywhere on the hood surface.\83\ Consistent with GTR 9,
the first step in establishing these areas would be to identify the
``Hood Top.'' \84\ The Hood Top forms the basis upon which all other
areas are determined. We discuss the method for determining the Hood
Top in section VI.A below. The next step would be to establish the
``Hood Area'' using the procedures discussed in section VI.B below.\85\
The final step in the process would be to determine the test areas,
i.e., the Child and Adult Headform Test Areas. As part of this process,
consistent with GTR 9's 82.5 mm margins, the standard would identify
``HIC Unlimited Areas'' \86\ and exclude them from meeting HIC limits.
While the agency is unaware of data that indicates there is a lower
likelihood of pedestrian head contact in this area compared to other
areas of the hood, the GTR and proposed standard provide for HIC
Unlimited Areas as a practicability measure to accommodate a
manufacturing need to reinforce and stiffen the hood edges.\87\ The HIC
Unlimited Area bounds the Child and Adult Headform Test Areas at the
hood edge.
---------------------------------------------------------------------------

\83\ Koetje B and Grabowski J. A Methodology for the Geometric
Standardization of Vehicle Hoods to Compare Real-World Pedestrian
Crash; Annuals of Advances in Automotive Medicine. 2008; 52: 193-
198.
\84\ The Hood Top is identical to the ``Bonnet Top'' of GTR 9.
\85\ As we will describe below, in some instances the Hood Area
may be equivalent to the Hood Top.
\86\ NHTSA would use the procedures in the standard to identify
the HIC Unlimited areas and would not use manufacturer data to
define them. We note that GTR 9 does not use the ``HIC Unlimited''
terminology, but makes the same reduction to the testable area.
\87\ As noted earlier, such reasons include the need to minimize
any fluttering of the hood at high speeds and the ability to slam
the hood shut without deforming the seams at the junction of the
hood and fender.
---------------------------------------------------------------------------

Portions of the Child and Adult Headform Test Areas are either
subject to HIC1000 or HIC1700 limits. The requisite HIC1000 area that
is calculated based on the total Hood Area must be located within the
Child and Adult Headform Test Areas and are not part of the HIC
Unlimited Area. Proposed FMVSS No. 228 would provide manufacturers
considerable leeway in determining where to place the HIC1700 area to
afford them as much flexibility as reasonably possible in configuring
the structures comprising their under-hood designs. The vehicle
manufacturer would inform NHTSA of the locations of the HIC1700 areas.
NHTSA would use that information to confirm that sufficient HIC1000
area has been provided, delineate the HIC1700 areas, and confirm
through headform test results that the appropriate HIC limits are met.

A. Determining the Hood Top

The Hood Top is enclosed by the intersection of the following
borders (these borders are depicted in figure VI.1 below):
Front border: Leading Edge Reference Line.
Side border: Side Reference Lines.
Rear border: Rear Reference Line.
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1. Front Border of the Hood Top
The front border of the Hood Top would consist of the vehicle's
``Leading Edge Reference Line'' (LERL). The LERL is determined for most
vehicles by running a 1,000 mm straight edge angled at 40[deg] (down
from the horizontal) along the front edge of the vehicle. The lower end
of the straight edge is specified to be 600 mm off the ground. The
specified height of 600 mm was chosen to avoid the bumper when marking
off the hood leading edge. (See figure VI.2 below, illustrating the
procedure.) The length and angle of the straight edge result in the
upper end being placed at 1,243 mm from ground level. The use of a
40[deg] angle provides an objective means to delineate the grille/
bumper from the hood. Moving along the width of the front-end and while
holding the straight edge parallel to the vehicle x-z plane, the
contact points between the straight edge and the vehicle define the
line. The reference to a 1,000 mm long straight edge is in the GTR. Our
understanding is the 1,000 mm length of the straight edge was chosen
for convenience, and may be a result of previous pedestrian test
protocols.\88\
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\88\ We will discuss later below how, for a subset of vehicles,
the straight edge length affects the front hood border.

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[[Page 76939]]

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2. Side Borders of the Hood Top
The side borders of the Hood Top would be determined by identifying
the Side Reference Lines (SRLs). An SRL would be drawn by running a
straight edge angled at 45[deg] along the side of the vehicle. Unlike
in the procedure establishing the LERL, the straight edge is not held a
fixed distance from the ground when determining the SRL. The 45[deg]
angle provides an objective means to delineate the fender from the
hood. Moving along the length of the vehicle, the contact points
between the straight edge and the vehicle define the SRL. The side
border has been defined this way in all previous test protocols
preceding the GTR, including those of the EEVC, IHRA, ISO, and NHTSA's
earlier work on a pedestrian protection standard. It is also used in
Euro NCAP. (See figure VI.3, provided for illustration purposes.)
[GRAPHIC] [TIFF OMITTED] TP19SE24.009

[[Page 76940]]

3. Rear Border of the Hood Top
The rear border of the Hood Top would be determined by identifying
the Rear Reference Line (RRL). The RRL would be determined by inserting
a 165 mm sphere into the cowl \89\ and against the windshield such that
the sphere is in contact with the windshield and a point on the surface
of the hood (usually its rear edge). The RRL is formed by moving the
sphere along the width of the windshield while always keeping the
sphere in contact with the windshield and the hood. The contact points
between the sphere and the hood define the RRL. (See figure VI.4,
provided for illustration purposes.)
---------------------------------------------------------------------------

\89\ The cowl is the lower edge of the windshield opening. The
wiper blades, linkages, and arms are removed during this process
defining the RRL.
[GRAPHIC] [TIFF OMITTED] TP19SE24.010

BILLING CODE 4910-59-C
4. Provisions for Front Corners
The GTR is at times ambiguous regarding where to pinpoint the
intersection of the Leading Edge Reference Line (LERL) and the Side
Reference Line (SRL) defining the Hood Top. The front border of the
Hood Top is defined by the LERL. On vehicles that were on the road
fifteen or more years ago, the hood front border did not have a high
degree of curvature, and the point of intersection with the side border
was easy to discern. However, on newer models, the LERL is usually
curved and often not smooth--such that it may be possible for the side
border to intersect in more than one place (although we expect such
occurrences to be rare). This is depicted in the figure below (figure
VI.5).

[[Page 76941]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.011

To identify the boundaries for the Hood Top, it is important for
NHTSA to know where the LERL intersects the SRL. In European test
protocols used today (e.g., Euro NCAP V7.0 and later versions, UNECE
Reg. No. 127), a ``Corner Reference Point'' for the Hood Top is defined
to clarify this situation (shown graphically in figure VI.5). In those
test protocols, the Corner Reference Point is the intersection of the
LERL and the SRL. Additionally, Euro NCAP clarifies that if there are
multiple intersections, the most outboard intersection comprises the
Corner Reference Point.\90\ We have included a definition of ``Corner
Reference Point'' in our proposal for the same purpose, which would
make clear that the Corner Reference Point of the Hood Top is the most
outboard intersection when the LERL and the SRL intersect at multiple
points.
---------------------------------------------------------------------------

\90\ GTR 9 does not define a Corner Reference Point and makes no
provision of multiple intersections between the LERL and SRL.
---------------------------------------------------------------------------

As we discuss below, there are other areas defined on the vehicle
hood that may also have multiple intersections at the front corners. To
be clear in the proposed standard as to how the areas are determined,
we are also similarly defining the ``Corner Reference Point of the
Child Headform Test Area'' and the ``Corner Reference Point of the Hood
Area.''
Finally, as mentioned previously, there is a proposed provision for
determining the LERL of a high front vehicle when the tip of the
straight edge makes first contact with the vehicle as opposed to
elsewhere on the straight edge (see figure VI.16 later in the
document). In such an instance, consistent with GTR 9, the WAD1000 line
becomes the LERL. However, when this procedure is followed, it is
likely that the WAD1000 line and SRL would not intersect due to their
height difference, and thus, using procedures that would apply to
vehicles of lower front ends, the Corner Reference Point of the Hood
Top cannot be determined. To correct this deficiency, proposed FMVSS
No. 228 would provide a procedure to connect the SRL to the WAD1000
line and thus establish the Corner Reference Point of the Hood Top.
This procedure involves establishing the Corner Reference Point of the
Hood Top as if the LERL were determined by contact with the straight
edge. The SRL and the WAD1000 line are then connected by a line
spanning the distance from the Corner Reference Point of the Hood Top
and the WAD1000 line.
5. Provisions for Rear Corners
When the sphere and cowl procedure is conducted, often the RRL does
not intersect the SRL, i.e., the edges of the lines do not meet at the
corners. Because it is important to defining the test area that the
hood borderline be continuous, proposed FMVSS No. 228 provides an
objective way to connect these two lines using a procedure in GTR
9.\91\ FMVSS No. 228 would specify that the RRL is extended using a
semi-circular template of radius 100 1 mm, marked with
four reference marks ``A'' through ``D,'' as shown in figure VI.6.
---------------------------------------------------------------------------

\91\ GTR 9, section 3.6, p. 38.

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[[Page 76942]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.012

The template would be placed on the vehicle with corners ``A'' and
``B'' coincident with the side reference line. With these two corners
remaining coincident with the side reference line, the template would
be slid gradually rearwards until the outer edge of the template makes
first contact with the RRL. If the first point of contact between the
template and RRL lies outside the arc identified by points ``C'' and
``D,'' the RRL is extended and/or modified to follow the
circumferential arc of the template to meet the SRL, as shown in figure
VI.7 (provided for illustration purposes).

[[Page 76943]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.013

If the outer edge of the template shown in figure VI.6 cannot
contact the rear reference line while simultaneously contacting the
side reference line at points ``A'' and ``B,'' or the point at which
the rear reference line and template make first contact lies within the
arc identified by points ``C'' and ``D,'' then the standard prescribes
that larger templates must be used where the radii are increased
progressively in increments of 20 mm, until all the criteria above are
met.
6. Clarifying the Borders
Through years of researching pedestrian head protection using the
procedures described in the GTR, NHTSA has seen instances where the GTR
is silent or ambiguous about its application to some aspects of hood
design. NHTSA has developed ways to address these challenges consistent
with the GTR and NHTSA's Safety Act requirements such that the FMVSS
set forth objective and repeatable criteria. We propose to incorporate
these lessons learned into FMVSS No. 228's test procedures and
criteria, some of which are highlighted below.
a. Addressing Discontinuities and Abrupt Direction Changes When
Scribing the Side Reference Lines
In marking off the SRL using the straight edge, a contour on the
hood or fender could create a continuous line with sudden changes in
direction, or zigzagging in what was previously a relatively smooth
line. NHTSA considers this marked-off side border a valid SRL and would
not smooth out the line in a compliance test as may be customary in the
European approval process.\92\
---------------------------------------------------------------------------

\92\ Pedestrian Protection--ACEA Interpretations to the
Respective Legislation of the UNECE and the European Union, revised
November 30, 2010, Brussels. This document provides supplemental
definitions to several test procedures of GTR 9 that ACEA considered
to be ambiguous. ACEA is the European Automobile Manufacturers
Association, a group representing European-based automobile
manufacturers. https://www.acea.auto/acea-members/.
---------------------------------------------------------------------------

Yet, some vehicle contours may result in a discontinuous line (a
line with a break in it). In other words, a ``jump'' could occur such
that the border is no longer continuous because the points contacted by
the straight edge alternated between portions of the vehicle surface
separated by some distance. See figure VI.8 below, which depicts a
hypothetical vehicle with a discontinuous SRL (discontinuity is not to
scale). As shown in the figure, in this situation, NHTSA would ``fill
in'' the gap and make the broken line whole again using a procedure
that involves holding a non-stretch wire taut across the gap in the
line. The break is filled by scribing a line created by the projection
of the wire vertically downward on the vehicle surface. This procedure
also results in a zigzagging final line, which is an acceptable
outcome.

[[Page 76944]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.014

b. Multiple Contact Points
NHTSA has also encountered situations using the straight edge where
the vehicle may be contoured such that the straight edge contacts two
points at once (see figure VI.9). Such a situation could occur when
scribing any of the hood borders. To address this, where multiple or
continuous contacts occur NHTSA would use the contact that provides the
largest Hood Top (i.e., the most outboard contact point for the side
boundary, forward-most for the front boundary, and rearward-most for
the rear boundary). This convention is also specified in Euro NCAP and
the NCAP RFC for side borders. (We note that, as discussed in the next
section, the procedure for scribing the Leading Edge Reference Line
(LERL) uses a different strategy as a first step to avoid multiple
contact points when scribing the line. The convention described above
would be used if multiple contact points occur even after using that
initial step.) We note that GTR 9 specified the ``highest points of
contact'' with the 700 mm straight edge when tracing the side reference
line. In the example in figure VI.9, this would actually result in a
more inboard point defining the SRL. However, in practice this is
unlikely to result in any meaningful difference in the defined Hood
Top.

[[Page 76945]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.015

7. Special Provisions for the Leading Edge of the Hood
As explained earlier, NHTSA uses a straight edge to define the LERL
of the hood. Similar to the side border, this front border of the hood
may have multiple points of contact when using the straight edge held
at 40[deg] from the horizontal. If continuous or multiple points of
contact result, this NPRM (consistent with the GTR) specifies adjusting
the angle of the straight edge from 40[deg] to 50[deg] from the
horizontal to try to achieve a single point of contact.^{93 94}
See figure VI.10 below, provided for illustration purposes. (This also
has the effect of extending the LERL forward and thus increasing the
headform test area, which NHTSA believes is desirable and consistent
with safety.) We note that NHTSA is also proposing objective ways to
determine whether there is ``continuous contact'' or ``multiple contact
points'' for assessing if the straight edge angle must change. Such a
provision is not specified in GTR 9. A continuous contact would be
established when the vehicle surface is within 0.5 mm of the straight
edge for at least 50 mm of the straight edge. Contacts would have to be
separated by at least 50 mm on the straight edge to be considered
multiple contacts.
---------------------------------------------------------------------------

\93\ Paragraph 3.5. ``Bonnet leading edge reference line.''
\94\ If this happens, the whole leading edge mark-off process is
restarted using the 50[deg] incline for the entire leading edge,
even though the discrepancy may have occurred at only one spot.

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[[Page 76946]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.016

As is the case with the Side Reference Lines, a zigzagging final
front border is an acceptable result. If there are gaps in the line,
NHTSA would fill in the gaps using a non-stretch wire held taut across
the gap in the line. The break is filled by scribing a line created by
the projection of the wire vertically downward on the vehicle surface.
Any protruding hood ornaments would be removed when drawing the LERL if
they have the effect of pushing the border rearward (and reducing the
test area).
One additional special provision of the LERL relates to vehicles
where the only contact of the straight edge is at its upper tip.
Consistent with the GTR, as the straight edge is moved laterally across
the front of the vehicle, if the upper tip is the only contact point,
the WAD1000 line is the LERL at this location. Additional discussion on
this topic is presented later in this document.

B. Hood Area

After identifying the Hood Top, the next step is to establish the
``Hood Area.'' \95\ The Hood Area (see light grey area in figure VI.11)
is enclosed by the intersection of the following borders:
---------------------------------------------------------------------------

\95\ For some vehicles, the Hood Area may be equivalent to the
Hood Top. Also, we note that GTR 9 does not define a Hood Area. In
GTR 9, the equivalent area would be what GTR 9 refers to the
``combined child and adult headform test areas.'' We have defined
Hood Area for increased clarity.
---------------------------------------------------------------------------

Front border: the Leading Edge Reference Line (LERL) or
the WAD1000 line, whichever is most rearward at the point of
measurement;
Side border: Side Reference Lines (SRL).
Rear border: Rear Reference Line (RRL), or the WAD2100
line, whichever is most forward at the point of measurement.
BILLING CODE 4910-59-P

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BILLING CODE 4910-59-C
1. Front Border of the Hood Area
Consistent with GTR 9, this NPRM proposes to use the most rearward
of either the WAD1000 line or the LERL in determining the front border
of what proposed FMVSS No. 228 would call the Hood Area. In the example
shown in figure VI.11 the Hood Area (light grey) does not completely
cover the Hood Top because the WAD1000 line is rearward of the LERL.
The cross hatched area shows the difference between the Hood Top and
Hood Area. WAD1000 is just under the average height of a 6-year-old
child (a target demographic of the standard), which is 1,150 mm. The
drafters of the GTR explained that a WAD of 1,000 mm was selected as
the forward boundary because real-world crash data show that over 80
percent of child pedestrian head contacts are above a WAD of 1,000
mm.\96\ Figure VI.11, above, shows an example of the WAD1000 line
defining the front edge of the Hood Area, rather than the LERL. As we
discuss in section VI.C.1, the front border of the Hood Area could be
the front border of the Child Headform Test Area on some vehicles. We
also discuss how we are considering shifting the front border of the
Child Headform Test Area to increase the area subject to the proposed
standard. (Conforming changes would be reflected in the front border of
the Hood Area if such a change were made.)
---------------------------------------------------------------------------

\96\ Paragraph 72 of the ``Safety Need'' section of GTR 9.
https://unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29registry/ECE-TRANS-180a9e.pdf.
---------------------------------------------------------------------------

2. Side Border of the Hood Area
The side borders for the Hood Area are the SRLs, which are also the
side borders for the Hood Top. The length of side borders may differ
from the Hood Top on some vehicles since the Hood Area may have
different rear and front borders than those of the Hood Top.
3. Rear Border of the Hood Area
Similar to the process for the front border, the first step in
establishing the rear border of the Hood Area is to locate the WAD2100
line (WAD2100). This NPRM's regulatory text proposes to use the most
forward of either WAD2100 or the Rear Reference Line (RRL) \97\ in
determining the rear border of the Hood Area. Strictly speaking, this
is different from GTR 9, which defines the rear boundary of the
equivalent area (rear reference line for the adult headform) as always
being WAD2100. We believe this is an error in GTR 9, because under this
reading of the GTR, even if the RRL were forward of the WAD2100 and
WAD2100 is in the windshield area (essentially off of the Hood Top),
WAD2100 still would be used as the rear border of the area in question.
This would affect the calculation of the amount of area that must
conform to a HIC1000 level, potentially including part of the
windshield or cowl. This outcome is not consistent with our
understanding of GTR 9.
---------------------------------------------------------------------------

\97\ As a reminder, the RRL is determined by inserting a 165 mm
sphere into the cowl and against the windshield such that the sphere
is in contact with the windshield and a point on the surface of the
hood (usually the cowl's rear edge).
---------------------------------------------------------------------------

This NPRM's regulatory text describes using the most forward of
either

[[Page 76948]]

WAD2100 or the RRL in determining the rear border of the Hood Area. For
most passenger cars, WAD2100 falls rearward of the cowl so the rear
border would be the RRL. However, WAD2100 could define the rear border
on some larger vehicles. Figure VI.12, below, shows an example of the
WAD2100 line defining the rear edge of the Hood Area, rather than the
RRL. Again, the cross hatched area shows the difference between the
Hood Top and Hood Area. As we discuss below, the rear border of the
Hood Area may not necessarily be the rear border of the Adult Headform
Test Area. In section VI.C.5, we discuss using WAD2500 rather than
WAD2100 as the rear reference line for the Adult Headform Test Area.
(Conforming changes would be reflected in the rear border of the Hood
Area if such a change were made.)
BILLING CODE 4910-59-P
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BILLING CODE 4910-59-C
4. Corner Reference Point of the Hood Area
As was the case with the Hood Top, we believe it is also necessary
to define a Corner Reference Point for the Hood Area to avoid any
ambiguity in pinpointing the intersection of the front and side borders
of the Hood Area. Obviously, when the Hood Top and Hood Area share the
same front border (LERL), the corner point is the same. However, when
the front border of the Hood Area is the WAD1000 line, the corner
points will be different, with the Corner Reference Point of the Hood
Area being at the intersection of the WAD1000 line and the side border,
and the Corner Reference Point of the Hood Top being at the
intersection of the LERL and the side border.

C. Defining the Child Headform Test Area and the Adult Headform Test
Area

Overview. Proposed FMVSS No. 228 defines a Child Headform Test Area
and an Adult Headform Test Area, which are contained within the Hood
Area.\98\ Consistent with GTR 9, under this NPRM the test areas have
been separated into child and adult regions because head strikes on the
hood in real-world collisions are dependent primarily on the collision
speed, the height of the pedestrian, and the shape of the vehicle
front-end.\99\ WAD is used for demarcation of the Child and Adult
Headform Test Areas because it is an excellent indicator of where a
pedestrian's head will strike a hood under a given set of
conditions.\100\
---------------------------------------------------------------------------

\98\ As noted earlier, this preamble occasionally refers to
these two test areas together as the ``Child and Adult Headform Test
Areas'' or ``the combined Child and Adult Headform Test Areas.''
\99\ Ivarsson BJ, Crandall JR et al (2007), Pedestrian head
impact- what determines the likelihood and wrap around distance?
Paper No. 07-0373, 20th International Technical Conference on the
Enhanced Safety of Vehicles Conference (ESV) in Lyon, France, June
18-21, 2007.
\100\ The crash scenario represented by the test is a non-
braking, 40 km/h impact. The suspension is set up for normal ride
attitude, not braking.

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[[Page 76949]]

Headform HIC Unlimited Areas
The Child and Adult Headform Test Areas are smaller than the Hood
Area to account for specified regions that are not subject to HIC
limits under the GTR, which we call ``HIC Unlimited Area.'' \101\ The
HIC Unlimited Area shares an outer boundary with the Hood Top. Its
inner boundary is called the HIC Unlimited Margin. The HIC Unlimited
Margin forms the outer boundary of the Child and Adult Headform Test
Areas.
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\101\ As explained previously, the standard would provide for
HIC Unlimited Areas as a practicability measure to accommodate a
manufacturing need to reinforce and stiffen the hood edges.
---------------------------------------------------------------------------

The Child Headform Test Area (See figure VI.13) is enclosed by the
intersection of the following borders:
Front border: HIC Unlimited Margin of the Leading Edge
Reference Line.\102\
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\102\ As explained later in this section, this is either the
82.5 mm offset line or the WAD1000 line, whichever is more rearward.
---------------------------------------------------------------------------

Side borders: HIC Unlimited Margins of the Side Reference
Lines.
Rear border: WAD1700 line or the HIC Unlimited Margin of
the Rear Reference Line, whichever is most forward at the point of
measurement.
The Adult Headform Test Area (See figure VI.13) is enclosed by the
intersection of the following borders:
Front border: WAD1700 line.
Side borders: HIC Unlimited Margins of the Side Reference
Lines.
Rear border: HIC Unlimited Margin of the Rear Reference
Line.\103\
BILLING CODE 4910-59-P
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BILLING CODE 4910-59-C
The first step in determining the HIC Unlimited Margin would be to
establish a reference line by measuring an 82.5 mm (3.25 inches)
distance from each point along the four borders of the Hood Top. For
convenience, in this preamble we refer to this as ``the 82.5 mm offset
line.'' (See figure VI.14.) For example, the HIC Unlimited Margin of
the Side Reference Line is established by following the SRL along the
contour of the body in the y-z plane using the equivalent of a taut,
82.5 mm (3.25 inch) graduated wire. The regulatory text describes using
the wire to measure the 82.5 mm (3.25 inches) distance over any surface
bumps that may be present, such as ornamental trim. Since the wire is
taut, it would span any depressions (such as a seam between the hood
and fender) between the points on the SRL to the measured points. The
wire must not deviate from the y-z plane when establishing the HIC
Unlimited Margin of the Side Reference Line. Similarly, an 82.5 mm
offset line for the LERL and RRL would be drawn by measuring the
prescribed distance from each point along the LERL and RRL along the
contour of the body in the x-z plane using a taut, graduated wire.
---------------------------------------------------------------------------

\103\ As explained later in this section, this is either the
82.5 mm offset line or the WAD2100 line, whichever is more forward.

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[GRAPHIC] [TIFF OMITTED] TP19SE24.020

1. Front Border of Child Headform Test Area
The front border of the Child Headform Test Area is the HIC
Unlimited Margin of the Leading Edge Reference Line, which is the
WAD1000 line or the 82.5mm offset line, whichever is most
rearward.\104\ Figure VI.15 shows an example where the front border of
the Child Headform Test Area (right image) is formed by the 82.5 mm
offset line and the front border of the Hood Area is the WAD1000 line
(left image). As in figure VI.12, the left image shows the Hood Area
overlaid on the Hood Top (cross hatch showing the difference), with the
Hood Area being smaller because WAD1000 is rearward of the LERL. In the
right image we see that the test area begins rearward of the Hood Area
front border. The left image shows the borders of the Hood Area (light
grey area) and the right image the border of the Child and Adult
Headform Test Areas (dark grey). Note that in the right image any area
that is not part of the Child and Adult Headform Test Areas is part of
the HIC Unlimited area (this includes the light grey and the cross
hatched areas).
---------------------------------------------------------------------------

\104\ Note that the front border of the Child Headform Test Area
is the most forward border of the combined test area.

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[[Page 76951]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.021

c. Considerations for the Child Headform Test Area Front Border
The agency believes there are several provisions where it would be
worthwhile for FMVSS No. 228 to differ from GTR 9 with respect to the
front border of the testable area, particularly for vehicles that are
larger or smaller than typical size. NHTSA requests comment on these
approaches for possible inclusion in the final rule.
First, with respect to large vehicles, this NPRM's regulatory text
for FMVSS No. 228 reflects the provisions of GTR 9 regarding the
procedures for testing vehicles with higher front ends, like larger
light trucks, but the agency discusses in this section aspects that
NHTSA believes may be more appropriate for the U.S. fleet. To begin,
the GTR procedure is as follows: When establishing the front border of
the relevant Hood Top, Hood Area, and ultimately the Child Headform
Test Area, the first step is to use the 1,000 mm straight edge to
determine the LERL. As shown in figure VI.16, for passenger car
designs, the straight edge is held high enough to engage the vehicle's
front end. However, the upper leading edge of the hood for some full-
sized pickup trucks exceeds 1,243 mm, which is the highest point of the
straight edge from the ground. For these vehicles, the upper tip of the
straight edge would be the only point of contact with the vehicle. If
this occurs, consistent with S3.5 in GTR 9, by definition, the WAD1000
line becomes the LERL. (This provision may also come into play for flat
front EVs.) Thus, the front border of the Child Headform Test Area
would be established by the 82.5 mm offset line from the WAD1000 line.
In some vehicles this may be in the front grille area.
Large pickups and large SUV comprise about 18 percent of new
vehicle sales, and some vehicles are large enough that they will engage
the tip of the straight edge in this way, such as the MY 2022 Ford
F250.\105\ Given the prevalence of large vehicles in the U.S. fleet, we
believe there are several points worthy of discussion related to this
issue, and related to high or flat front vehicles in general. These are
discussed below.
---------------------------------------------------------------------------

\105\ 2021 Wards Automotive.

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[[Page 76952]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.022

i. Extending the Straight Edge
First, it would clearly be possible as a practical matter to extend
the straight edge to whatever length necessary to contact the vehicle
at the more typical front hood location. However, this may result in
loss of a significant amount of testable area in the grille and
associated safety benefits. Child and small adult pedestrian heads are
more apt to strike the grille than the hood top on these vehicles, so
extending the straight edge would reduce the real-world relevance of
the test as regards those pedestrian impacts. Therefore, the agency is
not inclined to make such an accommodation without a demonstration that
subjecting the grille to testing is infeasible, meeting the standard is
impracticable, or other such reason. In a section below, we request
comment on the practicability of meeting proposed FMVSS No. 228 in the
grille area.
ii. NHTSA Seeks a More Consistent Approach
The provision establishing the WAD1000 line as the LERL if the tip
contacts the vehicle sets up a provision in the standard that would
test vehicles with just slight hood height differences differently. In
vehicles such as that shown in the bottom part of figure VI.16, the
LERL would be WAD1000 because the tip of the straight edge contacts the
vehicle--and, as a result, because WAD1000 is in the grille, the grille
would be tested. However, for a vehicle with a slightly lower hood
height that just allows the straight edge to make contact with the hood
along the straight edge length and not at its tip, the LERL would not
drop to the WAD1000 line in the grille area--and so the grille area
would not be tested. NHTSA believes a more consistent and reasonable
approach could be one that determines the test area using data tied to
where head impacts are likely to occur, as opposed to an approach that
determines test area by the length of a straight edge. Thus, NHTSA
requests comments on an approach that establishes the WAD1000 line as
the front border of the test area for all vehicle testing. NHTSA
believes this approach is merited as it determines the test area based
on where head impacts would occur in the real world, rather than where
a straight edge makes contact. The agency poses specific questions at
the end of this section and requests comments on using this approach in
the final rule.
iii. Impact Angle Considerations
We request comment on the specifics of testing a grille area. As
described in the test procedure of the GTR, the child headform is
launched at 50 degrees down from the horizontal and would impact a
horizontal surface at 40 degrees from a purely perpendicular impact.
(The child headform impact angle is illustrated in figure V.3 of this
preamble.) Assuming, for simplicity, a vertical front face of a
vehicle, this

[[Page 76953]]

means the impact would be 50 degrees from purely perpendicular.
However, striking a grille in this manner would constitute a slightly
less direct impact and presumably a less severe test. We believe that,
in a real-world impact, the head of a child striking such a high front
end vehicle would have a trajectory more in line with the velocity
vector of the vehicle than the current launch angle of the child
headform. The Euro NCAP procedure and NHTSA's NCAP RFC allow for test
points on the front surface of the vehicle. Euro NCAP and the NCAP RFC
make an adjustment to the impact direction to 20 degrees when forward
of the LERL so as to produce a more perpendicular impact. Additionally,
if the LERL is between WAD930 and WAD1000, Euro NCAP monitors this
location with a 20-degree impact test performed at the LERL.\106\ NHTSA
plans to conduct research on headform testing in the grille area of
some pickup trucks using the proposed FMVSS No. 228 protocol to assess
its practicality, as well as the merits of a more direct
(perpendicular) impact. As discussed in the next section, depending on
the results, the final rule may adjust the impact angle of the headform
when the test is conducted in the grille area.
---------------------------------------------------------------------------

\106\ Monitors means the results could be called out but are not
part of the Euro NCAP scoring. See, Technical Bulletin 019--Headform
to Bonnet Leading Edge. https://www.euroncap.com/en/for-engineers/supporting-information/technical-bulletins/. This bulletin explains
that the result of this test will be monitored against a HIC value
of 650. Where a ``poor'' test result has been achieved, Euro NCAP
may choose to comment on this alongside the normal pedestrian
protection score. The results of these tests will not be reflected
in the pedestrian protection score or any other part of the overall
assessment.
---------------------------------------------------------------------------

iv. Apportioning of Test Area to HIC Levels
For these high front and flat front vehicles, the apportioning of
the amount of the test areas that must have a HIC1000 or less merits
discussion. As previously mentioned and discussed in more detail in
section VII of this preamble, the portion of the Combined Child and
Adult Headform Test Areas that must meet the HIC1000 provision must be
at least the numerical value of two-thirds of the Hood Area placed
inside of the Child and Adult Headform Test Areas. Because this two-
thirds calculation is made on the basis of a two-dimensional projection
on to a horizontal plane, if some of the Child Headform Test Area could
be on a front surface of a vehicle that is more vertical than
horizontal, this area would not be added to the Hood Area calculation
simply due to the method of calculation using the two-dimensional
projection onto a horizontal plane. The concern here is that this
vertical test area, even if considered part of the headform test area,
would not be considered in calculating the amount of required HIC1000
area. Stated another way, the vertical test area, or an equivalent
amount, would not have to meet HIC1000; it could be assigned only
HIC1700, which would result in the vehicle providing a lowered level of
head protection. (Comments are requested on this issue in the next
section.)
v. Shifting the Test Border Forward
This point relates to large vehicles in general where the upper
portion of the straight edge, but not the tip, makes contact with the
vehicle. For these vehicles, WAD1000 could be in the grille area,\107\
but under the GTR, the Child Headform Test Area begins well beyond
WAD1000, because the test area would begin at the 82.5 mm offset line
as it is more rearward than WAD1000. NHTSA is concerned that, for such
vehicles, under the GTR provisions the agency would not be testing the
areas of the hood that could be struck by children of the stature of a
6-year-old. As mentioned above, the NCAP RFC procedure allows for
testing to WAD1000, even when WAD1000 is forward of the LERL. In 2014,
NHTSA investigated how the different interpretations of the impact
point targeting methods could change the actual testable area of a
hood.\108\ Headform tests were performed along the forward-most border
of the test zone and, depending on which targeting method was used, the
actual point of first contact of the headform with the hood was either
on the border or slightly in front of the border (see table VI.1).
Although HIC was found to increase at first contact locations in front
of the border, the increase did not appear to have affected
conformance, i.e., impact points conforming to either HIC1000 or HIC
1700 remained below the required HIC limit. Based on these results,
NHTSA believes a requirement that vehicles meet FMVSS No. 228 with a 30
mm shift of the forward-most border seems practicable. We request
comments on this issue. We note that in section VII and XI of this
preamble, we also discuss the issue of whether proposed FMVSS No. 228
should reduce or eliminate the areas in which, under the GTR, HIC is
not assessed (the HIC Unlimited Area). Reducing or eliminating the HIC
Unlimited Area would also shift the forward-most border forward.
---------------------------------------------------------------------------

\107\ GTR data indicate that 6-year-old child head impacts start
at about WAD1000.
\108\ Details of these tests can be found in: Suntay B and
Stammen, JA (August 2018), Vehicle hood testing to estimate
pedestrian headform reproducibility, GTR 9 test procedural issues,
and U.S. fleet performance. Docket NHTSA-2008-0145-0014.

Table VI.1--HIC at Points Tested on the Forward-Most Border and at a Point Shifted Slightly Ahead of the Border
----------------------------------------------------------------------------------------------------------------
HIC comparison
----------------------------------
At point shifted HIC %
Vehicle At forward- about 30 mm increase
most border forward of
per GTR 9 border
----------------------------------------------------------------------------------------------------------------
2010 Buick Lacrosse........................................... 1026 1041 1.5
2010 Kia Forte................................................ 626 703 12.3
2010 Acura MDX................................................ 1283 1326 3.4
2010 Hyundai Tucson........................................... 638 670 5.0
2011 Jeep Grand Cherokee...................................... 651 874 34.3
2011 Honda Odyssey............................................ 1302 1379 5.9
----------------------------------------------------------------------------------------------------------------

[[Page 76954]]

vi. Testing Forward of WAD1000 for Small Vehicles
Regarding smaller vehicles, the NPRM's regulatory text reflecting
the GTR specifies that the forward border of the required test area
would be the 82.5 mm offset line or WAD1000, whichever is most
rearward. Under this proposed provision, requirements for head
protection would start at WAD1000 for most small vehicles as the
WAD1000 line is usually more rearward than the 82.5 mm offset line.
However, for many smaller vehicles WAD1000 is far up the hood, which
means much of the hood (the forward portion) would not be subject to
any headform testing. It does not appear there are practicability
barriers to headform testing of the hood on small vehicles, because
comparable areas of the hood on larger vehicles would be regulated
under the proposed standard and thus subject to headform testing.
Testing forward of WAD1000 would potentially add to the protection of
children with a standing height of less than 1,000 mm. As discussed
below, to increase the safety benefits of the rule, we are considering
an alternative provision that would test forward of WAD1000. NHTSA
requests comment on this issue.
Request for Comment on Modifying the Forward Border
Based on the above discussion, NHTSA requests comments on the
questions below to help the agency decide whether a final rule should
identify the forward border differently. Please comment on the
potential gain in safety benefits as well as any potential
practicability, cost, or technical issues.
The NPRM's regulatory text reflects the GTR 9 provision
that accounts for the situation where the tip of the 1,000 mm straight
edge defines the LERL (rather than a point further down along the
straight edge), such as when the tip of the straight edge could make
first contact with the grille of a subject vehicle. In this situation,
the WAD1000 line becomes the LERL. This means that the testable area
could potentially include the grille area of the vehicle (i.e.,
headform impacts could be conducted on the grille area of the vehicle).
We request comment on adjustments to the launch angle \109\ for such
impacts, to potentially make them more perpendicular to the impacted
surface to replicate a real-world impact more accurately. What impact
point condition/location should trigger a change in impactor launch
angle? Additionally, should the estimate of Hood Area be modified if
some portion of the Hood Top is in the grille area, such as using a
test area projection onto a vertical plane for the more vertical tests
areas?
---------------------------------------------------------------------------

\109\ The Child Headform is launched at 50 degrees down from the
horizontal and would impact a vertical surface at 50 degrees from a
purely perpendicular impact.
---------------------------------------------------------------------------

There may be large vehicles with a hood height slightly
lower than those where the straight edge tip contacts the vehicle
first, such that the provision to drop the LERL to WAD1000 is not
triggered. Additionally, the NPRM's regulatory text (reflecting the
GTR) specifies that, for large vehicles in general, the Child Headform
Test Area begins well rearward of WAD1000--i.e., well rearward of where
a child's head is likely to strike. However, NHTSA requests comments on
changing the front border of the Child Headform Test Area to be either
the Offset Line or WAD1000, whichever is forward-most, rather than
rearmost. An outcome of this change would be that, in some cases, the
test area would be forward of the Hood Top and conforming changes would
need to be made to maintain the test area within the Hood Top. We note
that the Euro NCAP and the NCAP RFC allow for testing at WAD1000, even
if it is forward of the LERL. Euro NCAP monitors performance at the
LERL as far forward as WAD930 if the LERL is forward of WAD1000,
although this does not factor into the score.
For many smaller vehicles the forward line where testing
is required is at WAD1000, far behind the LERL, which means much of the
hood (the forward portion) would not be subject to headform testing. We
note that subjecting these forward areas of the hood to the standard
may benefit children smaller than the average 6-year-old. A potential
way to subject the forward areas to testing could be the same as that
suggested above for larger vehicles, i.e., selection of the test area
boundary based on the forward-most of the WAD1000 or of the Offset
Line, rather than the rearward-most. We ask for comment on this issue
in the context of smaller vehicles.
As discussed above, another alternative on which we
request comment involves how the GTR determines the HIC Unlimited
Margin for the front and sides. (Impacts in the HIC Unlimited Margin
are not subject to any HIC limit.) The NPRM's regulatory text reflects
the GTR's specification that the margin would be determined using an
82.5 (3.25 inch) mm taut wire, but NHTSA finds merit in using a 50 mm
(1.97 inch) taut wire instead to increase the testable area, and reduce
the allowable area of the HIC Unlimited Margin.
2. Transition Between Child and Adult Headform Test Areas at WAD1700
Consistent with the GTR, proposed FMVSS No. 228 would separate the
Child Headform Test Area from the Adult Headform Test Area at WAD1700.
For many smaller vehicles, it is possible that there would be no Adult
Headform Test Area at all when the transition between the child and
adult test areas is drawn at WAD1700. Consistent with the GTR, proposed
FMVSS No. 228 would require that, if there is only a Child Headform
Test Area, the requirements that applied to the combined Child and
Adult Headform Test Area are applied to the Child Headform Test Area
alone. For example, at least two-thirds of the numerical value of the
Hood Area, when placed within the boundary of the Child Headform Test
Area (as opposed to the combined areas) must not exceed HIC of 1000
using the child headform. For the remaining area the HIC shall not
exceed 1700.

[[Page 76955]]

This NPRM uses WAD1700 to transition between the Adult and Child
Headform Test Areas because GTR data indicate that 6- to 15-year-old
child head impacts start at about WAD1000 and end at WAD1700. A 5th
percentile female has a standing height of an average 12-year-old child
and would likely have a head impact within the Child Headform Test
Area. Consistent with this, figure VI.17 below from the Pedestrian
Crash Data Study (PCDS) shows that for all adults, impacts start at
about WAD1400 and end at WAD2400. PCDS shows that about 70% of all
adult pedestrian head impacts are between WAD1000 and WAD2100.
Separating the genders, about half of adult female and one third of
adult male head impacts are between WAD1000 and W1700 (not depicted in
figure VI.17). As shown in figure VI.17, the WAD1700 represents the
75th percentile for children under age 10 and the 25th percentile for
all adults. Because stature distribution has remained stable over the
past two decades \110\ and because WAD has been shown to depend
primarily on the pedestrian's stature for a particular vehicle impact
speed,^{111 112 113} this WAD distribution would still be
representative today.
---------------------------------------------------------------------------

\110\ Fryar CD, Kruszon-Moran D, Gu Q, Ogden CL. Mean body
weight, height, waist circumference, and body mass index among
adults: United States, 1999-2000 through 2015-2016. National Health
Statistics Reports; no 122. Hyattsville, MD: National Center for
Health Statistics. 2018.
\111\ Ivarsson J, et al. ``Pedestrian Head Impact--What
Determines the Likelihood and Wrap Around Distance?'', 20th Enhanced
Safety of Vehicles Conference (2007); paper no. 07-0373.
\112\ Kiuchi T, et al. ``Comparative Study of VRU Head Impact
Locations,'' Sixth Expert Symposium on Accident Research (ESAR).
Hanover, Germany (2014).
\113\ Otte, D. ``Wrap Around Distance WAD of Pedestrian and
Bicyclists and Relevance as Influence Parameter for Head Injuries,''
SAE Technical Paper 2015-01-1461, 2015.
[GRAPHIC] [TIFF OMITTED] TP19SE24.023

Data show that child-adult overlapping of impacts occurs between
1400 and 1700 mm. The drafters of the GTR considered whether to use a
test method where the child and adult test areas overlap or whether a
step change should be used, and where it should be drawn. The goal was
to ensure that the transition area would provide protection against
both child and adult head impacts. The drafters considered an approach
to specify a test area (transition zone) in which both a child headform
and an adult headform would be used to assess compliance, because both
children and adults strike this area. Such a transition zone could, for
example, be WAD 1400--WAD1700 or WAD1500--WAD1700. They also
considered, and ultimately adopted, a sudden transition (step change)
approach. However, the NCAP RFC and Euro NCAP test procedures have
adopted a transition zone between WAD1500--WAD1700, where both
impactors must be used if the RRL is between WAD1500 and WAD1700.
The rationale supporting a step change approach is that a sudden
step change in hood performance is not

[[Page 76956]]

likely to be engineered into the design of a hood, and that a step
change approach reduces the need to conduct unnecessary headform tests.
In practice, a sudden step change produces a hood design with an area
around the transition line that is safe for both child and adult
pedestrians. Therefore, it was decided that a hood designed for
overlapping child-adult safety is effectively achieved without the need
to specify the use of two headforms. Further, a defined boundary at
1,700 mm provides a clearer approach. The GTR adopted the step change
approach with a transition at WAD1700, which biases protection towards
children. That is, the use of WAD1700 makes more of the hood tuned to
protect a child's head than an adult head. Rather than having to design
hoods for both head masses, the use of a non-overlapping transition at
WAD1700 allows safety in the transition area to be optimized for the
lighter headform.
Request for Comment on the Transition Zone
NHTSA tentatively agrees with the above reasons and has
drafted the regulatory text of proposed FMVSS No. 228 to specify a non-
overlapping transition from the Child Headform Test Area to the Adult
Headform Test Area at WAD1700. However, we request comments on the
merits of a transition zone. We would like to know more about the
degree to which a step change approach addresses safety for both adults
and children for vehicles that have sharp changes in structure, such as
the joint between the rear of the hood and the cowl, which may occur
along the transition line. This is indeed the case for many smaller
vehicles which have no Adult Headform Test Area at all when the
transition is drawn at WAD1700. While this helps with design
feasibility for such vehicles (requirements apply for the lighter
headform only), it may reduce the safety of such vehicles for shorter
adult pedestrians because the hood may not provide sufficient
penetration depth for the heavier adult headform. We therefore seek
comment on other options for FMVSS No. 228. These options may include a
revised procedure in which the adult/child border is drawn at a
different WAD and use of a transition area that is tested with both
headforms.
3. Rear Border of Adult Headform Test Area
Consistent with GTR 9, the rear border of the Adult Headform Test
Area is the HIC Unlimited Margin of the Rear Reference Line, which is
the WAD2100 line or the 82.5mm offset line, whichever is more forward.
WAD2100 is based on the average height of a 50th percentile adult male,
which is about 1750 mm. This height is about the 97th percentile for
adult females in the U.S.\114\
---------------------------------------------------------------------------

\114\ Based on 2007-2010 NHANES from https://tools.openlab.psu.edu/tools/explorer.php.
---------------------------------------------------------------------------

d. Considerations for the Adult Headform Test Area Rear Border; Request
for Comment
NHTSA is considering several changes to the GTR approach related to
the rear border of the Adult Headform Test Area to increase the test
area. These considerations offer the potential of providing increasing
pedestrian protection to individuals taller than the average male, and
to individuals involved in higher speed impacts.
1. First, we are considering including headform testing of the
windshield. This NPRM's regulatory text does not include testing of the
windshield, A-pillars or top edge of the windshield, which is
reflective of GTR 9's text. The GTR excludes the A-pillars and top edge
of the windshield from the test area because of practicability reasons,
and NHTSA generally agrees with excluding those areas. It is difficult
to reduce the stiffness of the windshield frame because it serves as a
support structure and helps to ensure the integrity of the occupant
compartment. Furthermore, in the lower windshield area the requisite
deformation space to meet HIC is restricted by the dashboard and
instrument panel. Some components must be positioned in the dashboard
and instrument panel to provide occupant protection (e.g., air bags)
and crash avoidance safety, e.g., defrosting requirements, forward-view
sensors for automatic emergency braking, and rearview cameras. In
addition, the structural components of the dashboard comprise important
load paths in front and side crashes that contribute to occupant crash
protection.
The GTR drafters excluded the windshield for different reasons,
finding that the windshield itself does not cause severe injuries and
therefore the number of casualties averted would be very low. The
center of the windshield--away from the edges--generally produces good
safety scores, although impacts near the A-pillars universally produce
poor results. This is consistent with real-world data which show that
fatal injuries are more common when the head strikes the windshield
frame rather than the center area.\115\
---------------------------------------------------------------------------

\115\ Fredriksson R (2011), Priorities and potential of
pedestrian protection--accident data, experimental tests, and
numerical simulations of car-to-car pedestrian impacts. Doctoral
Thesis, Department of Public Health, Karolinska Institutet,
Stockholm, Sweden, 2011.
---------------------------------------------------------------------------

Nonetheless, NHTSA is concerned that head-to-windshield impacts are
associated with a high incidence of pedestrian injuries. One reason is
that a head-to-windshield impact may have a higher velocity than a
head-to-hood impact.\116\
---------------------------------------------------------------------------

\116\ Kerrigan J, Arregui C, Crandall JC (2009), Pedestrian head
impact dynamics: comparison of dummy and PMHS in small sedan and
large SUV impacts, Paper No. 09-0127, 21st International Technical
Conference on the Enhanced Safety of Vehicles Conference (ESV)--
International Congress Center Stuttgart, Germany, June 15-18, 2009.
---------------------------------------------------------------------------

NHTSA has also observed that vehicle designs have changed in recent
years in that windshields are more forward on the hood, where the cowl
may begin at WAD1700. WAD1700 separates the Child Headform Test Area
from the Adult Headform Test Area. Because the area rearward of the
cowl is excluded from the headform test area, these vehicles have hoods
that would only have a Child Headform Test Area and would be tested
only with a child headform. NHTSA is concerned that these designs may
be particularly detrimental to shorter adult pedestrians who are more
apt to strike the hood near the cowl than in the case of designs of
predecessor vehicles whose cowls began at a higher WAD measurement.
Extending the test area into the windshield may serve to disincentivize
such designs by eliminating the compliance advantage that may come with
limiting the hood size to WAD1700. Further, the windshield itself on
these vehicles tends to be more horizontal than vertical, and so a
larger portion of the windshield lies directly above and near the
dashboard panel where there is less penetration depth to protect the
head. The extended windshield (i.e., a windshield placed immediately
beyond WAD1700) may also be stiffer than the portion of the hood that
would otherwise have covered the same area. Extending the test area
into the windshield may serve to protect pedestrians who may strike
this stiffer portion of the windshield.
NHTSA has also observed the development of automated rideshare
vehicles and other modern EVs with very flat fronts, with the base of
the windshield or windshield-like areas at very small WAD locations
compared to traditional vehicles. For such vehicles, exclusion of the
windshield-like areas would essentially permit the vehicle to not
provide any form of pedestrian head protection.
Finally, as we noted above, some of these automated vehicles appear
to have

[[Page 76957]]

a windshield-like area, but it is not a windshield in the traditional
sense since it is not transparent. For such vehicles, the RRL would not
exist since it is determined by inserting a 165 mm sphere into the cowl
and against the windshield such that the sphere is in contact with the
windshield and a point on the surface of the hood (usually its rear
edge). For such vehicles, the rear boundary of the Hood Area and Adult
Headform Test Area would be defined by the WAD2100 line. Comments are
requested on how the test area should be determined for vehicles with
no traditional windshield and on the merits of determining the rear
boundary of the Hood Area and Adult Headform Test Area by WAD2100 for
such vehicles, as would be the case for the proposed regulatory text.
As for practicability, NHTSA has performed eleven tests into the
windshield as part of the testing documented in table VII.1, below. Of
those eleven tests, nine had HIC below 1000 and the other two tests
were HIC below 1700, which support a finding that testing of at least
some portion of the windshield may be reasonable and practicable.
It is the agency's understanding that UNECE Reg. No. 127 has a
proposal to specifically add the windshield as a new test area.\117\
This area is bound, in the front, by a line 100 mm rearward of the
blacked-out (non-transparent) portion of the windshield base and in the
rear by WAD2500 or a line 130 mm forward of the rear edge of the
windshield, whichever is more forward at a given lateral position. The
side border is 100 mm inside of the blacked-out area. Adding the
windshield to UNECE Reg. No. 127 would indicate the provisions of GTR 9
are appropriate for the windshield.
---------------------------------------------------------------------------

\117\ ECE/TRANS/WP.29/GRSP/2021/28.
---------------------------------------------------------------------------

Given the above, there appears to be merit to including
the windshield in a test area for FMVSS No. 228. The regulatory text of
this NPRM does not include the windshield, but NHTSA is considering
language for a final rule that would include the windshield. The NCAP
RFC and various international NCAP programs that assess pedestrian
safety (Euro NCAP, Japan NCAP, Korea NCAP, and Australian NCAP) include
a head-to-windshield impact test area. In addition, a UNECE Reg. No.
127 proposal also includes the windshield for testing.
2. The next subject for consideration is the limitation of testing
beyond WAD2100. Consistent with GTR 9, this NPRM's regulatory text
states that the rear border of the Adult Headform Test Area is either
WAD2100 or the HIC Unlimited Margin of the Rear Reference Line,
whichever is more forward. However, the ECE proposal mentioned above
changes WAD2100 to WAD2500. That is, the rear border of the Adult
Headform Test Area (``Adult Bonnet Top Headform Test Area'' in the ECE
proposal) would be changed from the forwardmost of WAD2100 or the 82.5
mm offset line, to the forwardmost of WAD2500 or the 82.5 mm offset
line. The change to WAD2500 would increase the test area. We are also
aware of similar changes to the Euro NCAP requirements being
implemented in 2023, with the area between WAD2100 and WAD2500 being
referred to as the Cyclist Zone.\118\ WAD2500 might extend past the
windshield to the roof, and, under Euro NCAP procedures, the A-pillars
are tested. Any impacts to the roof under Euro NCAP procedures involve
a 45-degree angle rather than 65 degrees. We are considering similarly
changing WAD2100 to WAD2500 for FMVSS No. 228.
---------------------------------------------------------------------------

\118\ Euro NCAP Vulnerable Road User Testing Protocol https://cdn.euroncap.com/media/70319/euro-ncap-vru-testing-protocol-v901.pdf.
---------------------------------------------------------------------------

The specification of WAD2100 recognizes that the point of head
contact--relative to the height of the pedestrian--moves further
rearward as pedestrian stature increases. WAD2100 corresponds to the
typical head impact location of a pedestrian with a height of 1,750 mm
for a vehicle speed of 40 km/h. A height of 1,750 mm is approximately
the height of a 50th percentile male. For most passenger cars and
minivans, WAD2100 lies rearward of the Rear Reference Line (RRL) (which
is at the cowl) so WAD2100 would not be consequential as it would not
be used to define the rear border of the hood area. However, for some
larger vehicles in the U.S., the WAD2100 line can be forward of the
RRL, which means that WAD2100 would be the rear border of the testable
area of the hood even though there could be parts of the hood rearward
of that WAD2100 line.\119\
---------------------------------------------------------------------------

\119\ NHTSA recognizes that moving the WAD line rearward to
account for head impacts rearward of WAD2100 could bear on other
aspects of the test procedure, such as the velocity of the headform
impact in the test, because actual pedestrian head impact velocities
are generally higher at WADs greater than 2100 mm. This means that,
if the WAD line were moved rearward of WAD2100, the agency would
carefully consider whether adjustments would be appropriate to the
test procedure to ensure the continued relevance of the procedure
relative to a real-world impact at WADs greater than 2100 mm.
---------------------------------------------------------------------------

We seek comment on moving the rear boundary of the test
area consistent with using WAD2500 as the reference, rather than
WAD2100. Such a change has been proposed for UNECE Reg. No. 127 and
Euro NCAP. We also seek comment on the need for a modified impact angle
for the roof, if moving to a WAD2100 boundary results in headform
testing in the A-pillar or roof areas.
3. Another issue that arises in defining the Adult Headform Test
Area rear boundary is that the GTR uses the most forward of either
WAD2100 or the 82.5 mm offset line. Figure VI.18 shows an example where
the WAD2100 is the rear boundary of the Adult Headform Test Area. For
the final rule, NHTSA is considering enlarging the test area rearward
by considering the most rearward of these borders.
Regardless of any change to the WAD reference, we request
comment on using the most rearward of the WAD line or offset line to
define the rear boundary of the Adult Headform Test Area, rather than
using the line that is most forward.
4. We are also considering reducing the HIC Unlimited Area by using
a 50 mm (1.97 inch) offset line rather than an 82.5 mm (3.25 inch)
offset line at the rear of the Hood Top. This HIC Unlimited Margin at
the rear of the Hood Top was originally written into the GTR to prevent
a test anomaly where the headform could hit the windshield and the hood
simultaneously. However, NHTSA believes that the use of the 165 mm
sphere to define the RRL works adequately to prevent situations where
the headform could contact the windshield and hood simultaneously. We
also note that the NCAP RFC and Euro NCAP do not consider impact points
on the hood that are a distance less than 50 mm from the Side Reference
Line (SRL) measured in the lateral direction; i.e., they use what
amounts to a 50 mm offset line rather than an 82.5 mm offset.
Accordingly, while the regulatory text of this NPRM uses
an 82.5 mm Offset Line, NHTSA is considering using a 50 mm Offset Line
rather that an 82.5 mm Offset Line to define the rear HIC Unlimited
Margin. The reduced Offset Line would make more of the hood on larger
vehicles subject to headform testing. NHTSA requests comments on the
merits of the agency's adopting a 50 mm Offset Line in the final rule.
5. Finally, we are considering and request comments on the merits
of including the entire Hood Top as the testable area. This would mean
the elimination of the HIC Unlimited Area completely, of both the Child
and Adult Headform Test Areas, and expansion of the front test border
to the LERL and the rear border to the RRL. We discuss this

[[Page 76958]]

in more detail in section XI, Considered Alternatives.
[GRAPHIC] [TIFF OMITTED] TP19SE24.024

4. Corner Reference Point of the Child Headform Test Area
Finally, we believe it is also necessary to define a corner
reference point for the test areas (specifically the Child Headform
Test Area), just as it is for the Hood Area. The rationale is the same
as for the Hood Area, i.e., we need to clearly define the extent of the
test area. There may be multiple intersections between the front border
of the Child Headform Test Area (HIC Unlimited Margin of the LERL) and
the side border of the Child Headform Test Area (HIC Unlimited Margin
of the SRL). The definition would make clear that we would be using the
most outboard intersection when there are multiple intersections of the
front and side borders. This term would be called the ``Corner
Reference Point of the Child Headform Test Area.''

VII. Proposed Requirements and Assessing Compliance

A. Amount of Hood Area That Must Conform to HIC1000

Consistent with GTR 9, the regulatory text of this NPRM prescribes
the amount of the Child and Adult Headform Test Areas that must conform
to a HIC1000 limit (HIC1000 Area). The remainder of the Child and Adult
Headform Test Areas must be able to conform to a HIC1700 limit (HIC1700
Area).
The basis for the minimum HIC1000 Area is the size of the Hood
Area. After the Hood Area is determined, the performance requirements
would be applied as follows:
(1) The numerical value of two thirds of the Hood Area is
calculated. At least this amount of area, when placed within the
boundary of the Combined Child and Adult Headform Test Area, must not
exceed HIC1000.\120\ As we explained in section VI.C, the Child
Headform Test Area and the Adult Headform Test Area are defined in a
manner that excludes ``HIC Unlimited'' margins in the Hood Area. Thus,
the requisite HIC1000 areas described in this paragraph (1) and in
paragraph (2) (below) must fit into the respective headform test areas
contained inside of the HIC Unlimited margins.
---------------------------------------------------------------------------

\120\ If the numerical value of two thirds of the Hood Area
exceeds the combined Child and Adult Headform Test Area, the entire
combined Child and Adult Headform Test Area must be HIC1000 Area.
---------------------------------------------------------------------------

(2) The numerical value of one-half of the Hood Area under WAD1700
is calculated. At least this amount of area, when placed within the
boundary of the Child Headform Test Area, must not exceed HIC1000.
(3) For all other tests, HIC must not exceed HIC1700.

[[Page 76959]]

In sum, under the provisions described above:
One-half of the numerical value of the Hood Area that lies
below WAD1700, when placed in the Child Headform Test Area, must meet
HIC1000.
At least two-thirds of the numerical value of the entire
Hood Area, when placed within the Combined Child and Adult Headform
Test Area, must meet the HIC1000 requirement.
In the event the numerical value of two-thirds of the Hood
Area exceeds the Combined Child and Adult Headform Test Area, the
entire Combined Child and Adult Headform Test Area must meet HIC1000.
There would be no HIC1700 area.
There may be cases where there is no Adult Headform Test
Area; in such cases, by definition, the Child Headform Test Area
represents the entire test area. In that case, the one-half requirement
in the Child Headform Test Area does not apply. Instead, the HIC
recorded shall not exceed 1000 over two-thirds of the Hood Area when
placed within the Child Headform Test Area, since it represents the
entirety of the test area. For the remaining Child Headform Test Area,
the HIC shall not exceed 1700. All tests in the Child Headform Test
Area would be with the child headform.
Proposed FMVSS No. 228 would provide manufacturers considerable
flexibility in designing their hoods to provide the protective HIC1000
area. They have the flexibility to account for hard points under the
hood that prevent the hood from meeting HIC1000. As explained below,
upon request, under NHTSA's enforcement authority, they must report
their design choices to NHTSA, so that the agency will know the
locations of the HIC1700 areas and can assess the compliance of the
vehicle based on that information.\121\
---------------------------------------------------------------------------

\121\ As discussed in section VIII.B below, there are pending
proposed GTR 9 amendments that would substantially reduce the amount
of required HIC1000 area.
---------------------------------------------------------------------------

B. Manufacturer Designations of HIC1700 Areas

Upon request and under the authority provided in 49 U.S.C. 30166,
manufacturers would be required to identify to NHTSA the HIC1700
portions of the test areas.\122\ The HIC1700 areas need not be
continuous and are not limited in number. They may consist of an
unlimited number of portions as long as the requisite HIC1000 area is
met by the vehicle. However, a manufacturer must attest to the
information by the time it certifies the vehicle, and the declaration
would be irrevocable. Thus, in a compliance test, manufacturers would
not be permitted to change the attestation and claim that an impact
that was previously designated as being in the HIC1000 area is now in a
HIC1700 area after the impact results in an HIC value above HIC1000.
---------------------------------------------------------------------------

\122\ In drafting this NPRM, NHTSA decided it would not matter
substantively if manufacturers had to identify the HIC1000 or the
HIC1700 portions, but identifying the HIC1700 portions seems more
straightforward since that area would be smaller than the HIC1000
areas.
---------------------------------------------------------------------------

FMVSS No. 228 would place some conditions on manufacturers'
designations of HIC1700 areas. When the HIC1700 area is contiguous with
reference lines, HIC Unlimited margins or WAD lines set forth in FMVSS
No. 228, the lines determined according to the standard would supersede
any conflicting coordinates provided by the manufacturer. In other
words, the borders as set forth in the standard are definitive and
NHTSA will use the procedures to determine the relevant areas on the
hood without manufacturer input.\123\ Upon request, manufacturers must
tell NHTSA where the HIC1700 areas are by providing coordinates or
decals. If these coordinates or decals conflict with the provisions of
FMVSS No. 228, NHTSA would conduct compliance tests using the reference
lines of the test area borders as determined by the standard, and not
the manufacturer's description of the location of test area borders.
---------------------------------------------------------------------------

\123\ When marking off the vehicle as described in this NPRM,
only the HIC1700 areas are derived from information supplied by the
manufacturer. All other borders will be drawn up on each individual
vehicle in accordance with the standard's regulatory text and
NHTSA's compliance test procedure (TP); they need not be determined
based on manufacturer information.
---------------------------------------------------------------------------

To enable more efficient compliance testing, this NPRM specifies
ways in which the HIC1700 areas would be disclosed to NHTSA. This NPRM
proposes to require manufacturers to identify HIC1700 areas by
providing the (x,y) coordinates of their borders referenced from the
intersection of WAD1000 and the longitudinal centerline of the
vehicle.\124\ The number of coordinates and the spacing of the
coordinates would be provided at the discretion of the manufacturer,
but the points would have to be joined by straight lines in the x-y
plane when marking off the test areas of an actual vehicle. In lieu of
(x,y) coordinates, we propose that the manufacturer could provide
decals or templates with registration marks (marks used for alignment)
referenced from the intersection of WAD1000 and the vehicle
longitudinal centerline.
---------------------------------------------------------------------------

\124\ If no HIC1700 area is provided by the manufacturer, the
child or adult test areas would be tested as HIC1000 area.
---------------------------------------------------------------------------

Request for Comment on Allocating HIC1700 Area
Under the GTR, when the Adult Headform Test Area is
relatively small compared to the Hood Area, it is possible in some
instances for a manufacturer to define all of the adult area as HIC1700
Area and still meet the requirement that the numerical value of two-
thirds of the Hood Area be HIC1000 Area. In such an instance there
would be no HIC1000 requirement for the adult headform. This raises a
concern to us because then, real-world adult pedestrian head strikes
would likely only be in HIC1700 area (and not in the more protective
HIC1000 area). We request comment on whether the final rule should
require that HIC1700 areas be allocated such that at least some HIC1000
area must be provided in the Adult Headform Test Area.

C. First Point of Contact

Under the proposed FMVSS No. 228 test procedures, with the agency
knowing the manufacturer's information identifying the HIC1700 areas,
NHTSA would launch a headform at the hood. The standard would take a
simple approach to determine the HIC requirement that applies to a
particular impact. For any given headform launch, NHTSA would identify
the first point of contact between the headform and the hood. NHTSA's
proposed method of targeting areas on the hood and assigning HIC values
through the first point of contact is consistent with NHTSA's
interpretation of GTR 9, and we refer to it as the ``3D Method.'' If
the impact is in a HIC1000 area, the headform must measure a HIC equal
to or less than 1000 for the vehicle to pass the test. If the impact is
in a HIC1700 area, the headform must measure a HIC equal to or less
than 1700. We will test as many points on the hood as we deem necessary
to assure the vehicle complies with the standard.\125\ If a test finds
that the HIC is greater than the limit prescribed by the standard, we
will investigate the finding as a potential noncompliance in accordance
with NHTSA's Office of Vehicle Safety Compliance protocol.
---------------------------------------------------------------------------

\125\ We recognize the potential that dents caused by headform
impacts on one part of the hood may affect the performance of the
hood in subsequent tests, depending on location of the impacts.
NHTSA's Office of Vehicle Safety Compliance (OVSC) will issue a test
procedure guidance document that would describe the agency's
protocol for conducting a compliance test. The test procedure would
explain NHTSA's protocol for changing out hoods between impactor
tests.

---------------------------------------------------------------------------

[[Page 76960]]

We recognize the possibility that the first contact of the headform
could occur at multiple points on the hood simultaneously due to the
curvature of the hood and the headform, and that these points could lie
in different test areas. For example, one point could lie in the
HIC1000 portion of the Child Headform Test Area and another could lie
in the HIC1700 of the Adult Headform Test Area. To address this
problem, we propose to use a simple and common-sense approach to cover
instances where the first contact occurs in more than one area: when
such a situation arises, the more stringent requirement applies.\126\
For example, if first contact occurs in a child HIC1000 area and a
child HIC1700 area simultaneously, the HIC1000 requirement applies for
that particular launch location. If the first contact occurs in both
the Child Headform Test Area and the Adult Headform Test Area (e.g.,
multiple simultaneous contact points), requirements for both headforms
would need to be met. That is, NHTSA could perform more than one test
of the same point with the different headforms.
---------------------------------------------------------------------------

\126\ With Contracting Parties like Japan and the E.U.,
situations like this are worked out between the manufacturer and the
type approval authority. In contrast, the Safety Act provides for a
self-certification framework--so NHTSA does not approve vehicles
before sale--and requires the FMVSS to be objective. This means that
the FMVSS must be capable of producing identical results when tests
are conducted in identical conditions and compliance must be based
on scientific measurements, not on opinions that could vary from
individual to individual and be subjective.
---------------------------------------------------------------------------

Proposed FMVSS No. 228 would not specify how many tests NHTSA would
conduct on a particular hood or where precisely the headforms would be
aimed (such as minimum spacing between the test points on the hood).
NHTSA agrees with the drafters of the GTR that the specification of
such points is not necessary because, for Contracting Parties such as
the United States that use a self-certification regulatory framework,
specifying the number of tests required for testing or the spacing of
test points is unnecessary. Under NHTSA's statutory framework and
proposed FMVSS No. 228, it would be incumbent on vehicle manufacturers
to ensure that their vehicles comply with all the impact zone
requirements defined within the standard when tested by NHTSA.
Accordingly, proposed FMVSS No. 228 does not specify these provisions.

D. Consideration Related to the Amount of Test Area That Must Meet the
HIC1000 and HIC1700 Limits

In section VII.A, we explained the requirement for the amount of
test area within the Child and Adult Headform Test Areas that must be
capable of achieving HIC not greater than 1000. The basis for this
amount of area is two-thirds of the Hood Area, and the Hood Area by
definition is always larger than the test area. Thus, more than two-
thirds of the test area must be HIC1000 Area, and the remainder (less
than two-thirds) must be HIC1700 Area. More than a decade and a half of
agency testing with the pedestrian headform to the specifications of
the GTR show that this level of performance is practicable.
NHTSA's pedestrian headform testing provides the data needed to
understand the distribution of HIC outcomes on U.S. vehicle hood areas.
Test data have been collected in numerous research studies \127\ that
have included 2001-2021 model year vehicles. These data, which also
include 6 data points for 1994 Honda Civic and 8 data points for 1999
Dodge Dakota, provide the basis for the estimates in the PRIA. Over the
years, this testing has kept NHTSA well-informed about the evolving
status of pedestrian protection for the U.S. vehicle fleet. A total of
344 headform impact tests were analyzed to understand the feasibility
of meeting both HIC1000 and HIC1700 performance requirements in both
central (within the Child and Adult Headform Test Areas) and peripheral
(near/outside the HIC Unlimited Margin \128\) areas of vehicle front
ends. Out of the 272 tests, only 28 (10.3%) of the impacts, regardless
of impact location, failed to meet HIC1700 (table VII.1). For tests
within the Child and Adult Headform Test Areas, 75 of 87 impacts
(86.2%) met the HIC1000 limit and another 10 impacts (11.5%) were
between HIC1000 and HIC1700. Only 2 impacts (2.3%) within the Child and
Adult Headform Test Area exceeded HIC1700. For tests near/outside the
HIC Unlimited Margin, 79 of 185 impacts (42.7%) met HIC 1000. Further,
when only model year 2010 or later vehicles are considered, there were
only 8 instances out of 155 tests (5.2%) that were above HIC1700,
including impacts in the HIC Unlimited Area. Again, restricting this to
tests in the proposed test area, 34 of 40 impacts (85%) were below
HIC1000, 5 of 40 (12.5%) were between HIC1000 and HIC1700 and 1 of 40
(2.5%) was above HIC1700.
---------------------------------------------------------------------------

\127\ Reference 1--NHTSA ``VRTC Pedestrian Research Activities''
GTR No. 9 Informal Working Group Document #WP29-144-03 (2006);
Reference 2--Mallory A, et al. ``Pedestrian GTR Testing of Current
Vehicles'' ESV (2007); Reference 3--Suntay B, et al. ``Vehicle Hood
Testing to Evaluate Pedestrian Headform Reproducibility, GTR No. 9
Test Procedural Issues, and U.S. Fleet Performance,'' NHTSA Docket
NHTSA-2008-0145-0014 (2018); Reference 4--Suntay B, et al.
``Pedestrian Protection: U.S. Vehicle Fleet Assessment,'' DOT HS 812
723 (2019); Reference 5--Suntay B, et al. ``Assessment of Hood
Designs for Pedestrian Head Protection: Active Hood Systems,'' DOT
HS 812 762 (2020); Reference 6--Suntay B, et al. ``Vehicle
Assessment using Integrated Crash Avoidance and Crashworthiness
Pedestrian Safety Test Procedures.'' DOT HS 813 521.
\128\ As explained earlier in this preamble, the ``HIC Unlimited
Margin'' is the inner boundary of the HIC Unlimited Area.
---------------------------------------------------------------------------

This analysis is considered a conservative approximation of
practicability (it underestimates the degree to which vehicles could
meet the proposed limits) for four reasons.
First, 109 of these 272 tests were conducted at the NCAP RFC and
Euro NCAP test velocity of 40 km/h, which is higher than the 35 km/h
speed proposed here. The HIC outcomes in those tests would be expected
to be lower if the proposed 35 km/h impact speed were employed at those
same impact locations. On the other hand, the 33 tests included in the
Ref. 1 study were conducted at 32 km/h since, at the time that research
was performed, the draft GTR procedure specified that lower impact
speed. Those same tests would be expected to have slightly higher HIC
at a speed of 35 km/hr. All of those test outcomes were included in the
analysis; however, it should be noted that there were over three times
as many tests at 40 km/hr as there were at 32 km/h in the sample.
Second, as noted earlier, vehicle designs have gotten more protective
over the years as evidenced by the lower HIC outcomes in more recent
vehicles.
Third, we note that certain tests have not been included in our
analysis of practicability, but note them here for completeness. Eleven
NHTSA tests into the windshield were not included since the windshield
is not covered by the GTR. However, of those eleven tests, nine had HIC
below 1000 and the other two tests had HIC below 1700, which supports a
finding that the HIC 1000 and 1700 limits are reasonable and
practicable. Finally, six tests on fully deployed pop-up hood systems
from two vehicles (see Ref. 5) were not included in this analysis,
since those tests included European-market-only hood actuator
components installed on a U.S. vehicle and it is unclear how such
vehicles would have been configured if FMVSS No. 228 were in place.
Nonetheless, all six of those tests had HIC below 1000. Taken together,
inclusion of these additional data would

[[Page 76961]]

indicate 17 tests with HIC below 1700 and 15 of 17 with HIC below 1000.

Table VII.1--Distribution of HIC Outcomes in NHTSA Testing
[MY 2001-2021 vehicles]
----------------------------------------------------------------------------------------------------------------
Child/adult test area Near/outside HIC unlimited margin
Source of data (vehicle model years) -------------------------------------------------------------------------
# Tests HIC <1000 HIC <1700 # Tests HIC <1000 HIC <1700
----------------------------------------------------------------------------------------------------------------
Ref. 1 (2001-2004).................... 11 11 11 22 12 19
Ref. 2 (1999-2006).................... 36 30 35 48 9 32
Ref. 3 (2010-2011).................... ......... ........... ........... 46 26 46
Ref. 4 (2015-2017).................... 31 26 31 51 21 46
Ref. 5 (2014)......................... 1 0 0 2 0 0
Ref. 6 (2016-2021).................... 8 8 8 16 11 16
-------------------------------------------------------------------------
Total............................. 87 75 85 185 79 159
Pct within HIC req.................... ......... 86.2% 97.7% ......... 42.7% 85.9%
----------------------------------------------------------------------------------------------------------------
* Note that impact locations with respect to the HIC Unlimited Margin needed to be estimated in some cases where
the margin was unknown. Also note that tests in this analysis included impact speeds from 32-40 km/h.
Therefore, these numbers should only be considered approximate with respect to the proposed 35 km/h test speed
and HIC Unlimited Margin locations on future vehicle front ends.

NHTSA understands that these data represent discrete points on the
hood surface tested in the program and do not describe the performance
of any particular vehicle hood in its totality. Nonetheless, taken
together, the analysis of existing NHTSA-performed pedestrian head
impact testing indicates that the proposed compliance limits and
requirements for proposed FMVSS No. 228 are practicable for U.S.
vehicles.

E. Considerations for Expansion of Test Area When It Is Less Than Two
Thirds of the Numerical Value of the Hood Area

Although very rare, based on the vehicles tested by NHTSA, it
appears possible for the numerical value of two thirds of the Hood Area
to exceed the Combined Child and Adult Headform Test Area.\129\ While
this can only occur when the test area is very small, NHTSA would like
to make clear that, in this situation, the proposal requires that the
entire Combined Child and Adult Headform Test Area be HIC1000 Area.
Stated differently, for such a vehicle, if there is no ``remaining
area,'' there would be no HIC1700 Area. We believe this view of the
proposed standard is consistent with GTR 9, but GTR 9 does not appear
to set forth any explicit contingencies for this occurrence. NHTSA
takes the view that the entire Combined Child and Adult Headform Test
Area must meet HIC1000 out of a concern that permitting a HIC1700 area
for such a vehicle would result in less than two thirds of the Hood
Area being tested to the HIC1000 threshold. This means that such a
vehicle would provide less protection to pedestrians than all other
vehicles (with larger hoods). Moreover, to address and improve upon
this situation, NHTSA is considering expanding the test area to
encompass at least two thirds of the Hood Area on these vehicles when
the test area, as currently defined, is smaller than two thirds of the
Hood Area. The entirety of the test area would remain HIC1000 Area to
remain consistent with the provision that the numerical value of two
thirds of the Hood Area be HIC1000 Area. NHTSA requests comment on
whether the test area increase should simply be a proportional
expansion of the entire test area.
---------------------------------------------------------------------------

\129\ The only vehicle tested by NHTSA where this occurred was
on the 2004 GM Savana. For this vehicle the numerical value of the
two thirds of the Hood Area was essentially the same as the Test
Area.
---------------------------------------------------------------------------

VIII. GTR 9 Terminology and Amendment 3

In drafting the regulatory text of this NPRM, one of NHTSA's goals
has been to produce a proposal that has a high degree of fidelity to
GTR 9. However, we have found the need to define some terms in a
slightly different way than the GTR to produce an objective standard
that meets the requirements of the Safety Act and the needs of the
self-certification environment in the United States. In this section,
we highlight some of the differences in terminology between GTR 9 and
FMVSS No. 228, after which we provide details related to, and request
comments on, an ``Amendment 3'' proposal that has since 2021 reemerged
as the source of potential revisions to GTR 9.

A. Comparison of Terminology

As we explained in section VI of this preamble, the major
components that constitute the hood are the Hood Top, Hood Area, Child
Headform Test Area, Adult Headform Test Area and HIC Unlimited Area. In
some cases, GTR 9 uses identical or very similar terminology; however,
the terminology sometimes does not have the same meaning. In other
cases, the terminology is different or the terms do not exist. Table
VIII.3 references the terms defined in FMVSS No. 228 (first column) and
the related terms in GTR 9 (second column). The focus here is on the
terms used to define the hood surface and tested area.
The term Hood Top and its related borders, shown in rows 1-4 of
table VIII.3, has equivalents in GTR 9, i.e., Bonnet Top, Side
Reference Line, etc. The term Hood Area in FMVSS No. 228 is represented
in GTR 9 by the combined child headform test area and adult headform
test area. We note that the GTR 9 child headform test area and adult
headform test area are larger than the similarly named areas in FMVSS
No. 228, because GTR 9 does not subtract the HIC Unlimited Area from
the GTR child and adult headform test areas. Just as the Hood Area
forms the basis of the amount of area needing to have a HIC of 1000 or
less in this NPRM, GTR 9 states at S5.2.3 that ``two thirds of the
combined child and adult headform test areas'' must meet this
requirement. Hood Area and the analogous GTR terms are shown in rows 5-
8 of table VIII.3.
The area described in the ``Child Headform Test Area'' term in
FMVSS No. 228 is not described by a specific term in GTR 9. However, an
equivalent set of borders for defining the area is provided in S7.3.2
of GTR No. 9 (see table VIII.1).

[[Page 76962]]

Table VIII.1
------------------------------------------------------------------------
S7.3.2 of GTR 9
-------------------------------------------------------------------------
Selected impact points on the bonnet for the child headform impactor
shall be, at the time of first contact:
(a) a minimum of 82.5 mm inside the defined side reference lines,
and;
(b) forward of the WAD1700 line, or,
a minimum of 82.5 mm forwards of the bonnet rear reference line,
--whichever is most forward at the point of measurement, and;
(c) be rearward of the WAD1000 line, or,
a minimum of 82.5 mm rearwards of the bonnet leading edge reference
line,
--whichever is most rearward at the point of measurement.
------------------------------------------------------------------------

Rows 9-12 in table VIII.3 show the corresponding regulatory text
sections related to Child Headform Test Area.
Similarly, ``Adult Headform Test Area'' in FMVSS No. 228 does not
have an equivalent term in GTR 9. However, an equivalent set of borders
for restricting the testing is provided in S7.4.2 (see table VIII.2)

Table VIII.2
------------------------------------------------------------------------
S7.4.2 of GTR 9
-------------------------------------------------------------------------
Selected impact points on the bonnet for the adult headform impactor
shall be, at the time of first contact:
(a) a minimum of 82.5 mm inside the defined side reference lines,
and;
(b) forward of the WAD2100 line, or,
a minimum of 82.5 mm forward of the bonnet rear reference line,
whichever is most forward at the point of measurement, and;
(c) rearward of the WAD1700 line.
------------------------------------------------------------------------

Rows 13-16 in table VIII.3 show the corresponding regulatory text
sections related to Adult Headform Test Area.
Although there are terminology differences between FMVSS No. 228
and GTR 9, the regulatory text of this NPRM is essentially aligned with
GTR 9. To the extent there are differences, the differences would
enable the proposed standard to meet Safety Act requirements. As
discussed throughout this preamble, however, the NPRM's regulatory text
reflects the wording of the GTR to benchmark the GTR's concepts and
methods implemented as an FMVSS. NHTSA has requested comments on the
pros and cons of various aspects of the NPRM's regulatory text,
particularly with respect to the areas of the vehicle that would be
subject to headform testing under the GTR's wording, and has focused
readers on ways NHTSA believes the regulatory text could possibly be
enhanced to achieve more safety benefits in the U.S.

Table VIII.3--Comparison of Terms Used to Hood Surface and Test Area in
FMVSS No. 228 and GTR 9
------------------------------------------------------------------------
Row No. FMVSS No. 228 GTR 9
------------------------------------------------------------------------
1............... Leading Edge Reference Line Bonnet leading edge
(S6.3.2). reference line (S3.5).
2............... Side Reference Line (S6.3.3). Side reference line
(S3.24).
3............... Rear Reference Line (S6.3.4). Bonnet rear reference
line (S3.6).
4............... Hood Top (S6.5.1)............ Bonnet Top (S3.7).
5............... Hood Area (S6.5.2)........... Combined child and
adult headform test
areas (S3.12 and
S3.1).
6............... Hood Area front border Front reference line of
(S6.5.2(a)). the child headform
test area (S3.15).
7............... Hood Area side border Side reference line of
(S6.5.2(b)). the child and adult
headform test areas
(S3.12 and S3.1).
8............... Hood Area rear border Rear reference line for
(S6.5.2(c)). adult headform
(S3.23).
9............... Child Headform Test Area No equivalent term
(S6.5.3). defined, but
essentially dictated
by S7.3.2.
10.............. Child Headform Test Area No equivalent term
front border (S6.5.3(a)) = defined, but
HIC Unlimited Margin of the essentially dictated
Leading Edge Reference Line by S7.3.2(c).
(S6.4.2).
11.............. Child Headform Test Area side No equivalent term
border (S6.5.3(b)) = HIC defined, but
Unlimited Margin of the Side essentially dictated
Edge Reference Line (S6.4.3). by S7.3.2(a).
12.............. Child Headform Test Area rear No equivalent term
border (S6.5.3(c)). defined, but
essentially dictated
by S7.3.2(b).
13.............. Adult Headform Test Area No equivalent term
(S6.5.4). defined, but
essentially dictated
by S7.4.2.
14.............. Adult Headform Test Area No equivalent term
front border (S6.5.4(a)). defined, but
essentially dictated
by S7.4.2(c).
15.............. Adult Headform Test Area side No equivalent term
border (S6.5.4(b)) = HIC defined, but
Unlimited Margin of the Side essentially dictated
Edge Reference Line (S6.4.3). by S7.4.2(a).
16.............. Adult Headform Test Area rear No equivalent term
border (S6.5.4(c)) = HIC defined, but
Unlimited Margin of the Rear essentially dictated
Reference Line (S6.4.1). by S7.4.2(b).
------------------------------------------------------------------------

[[Page 76963]]

B. Amendment 3

As early as 2011, in discussions at WP.29, the International
Organization of Motor Vehicle Manufacturers (OICA) \130\ suggested an
amendment to the GTR that would have changed the existing GTR protocol
as well as the method of determining the allotment of HIC1000 and
HIC1700 Area (discussed above in section VII of this preamble).\131\
This suggested proposal was then officially taken up by the Netherlands
in November 2011.\132\ The proposal was revised and listed at the 55th
GRSP meeting (May 2014) as Amendment to Phase 1.\133\ Action on this
document was deferred for many years, until a 2021 version (Amendment
3) submitted by the Economic Commission for Europe was brought back up
for discussion for a possible introduction into GTR 9.\134\ NHTSA had
concerns about the suggested amendment and did not support it in either
the 2011 or 2021 form and the suggestion, to date, has not been
adopted. Below we discuss the two main aspects of the proposal. The
first significantly reduces the amount of test area that must conform
to a test value with a HIC1000 limit. The second changes the way test
target points are determined, which has the potential to shrink the
amount of test area at the HIC Unlimited Margin of the Side Reference
Line. We discuss these changes here and seek comment because domestic
auto manufacturers have recently contacted NHTSA to express support for
Amendment 3.\135\
---------------------------------------------------------------------------

\130\ OICA was actively involved in the working group meetings
developing GTR 9. OICA's website states that its members represent
the global auto industry. It is known as the ``Organisation
Internationale des Constructeurs d'Automobiles (OICA).''
www.oica.net.
\131\ Proposal of Amendments to GTR 9 (Pedestrian safety), WP.29
Informal document GRSP-49-09, 49th GRSP Meeting, 16-20 May 2011.
https://unece.org/DAM/trans/doc/2011/wp29grsp/GRSP-49-09e.pdf.
\132\ ECE/TRANS/WP.29/2011/148, https://unece.org/DAM/trans/doc/2011/wp29/ECE-TRANS-WP29-2011-148e.pdf.
\133\ ECE/TRANS/WP.29/GRSP/2014/5, https://unece.org/DAM/trans/doc/2014/wp29grsp/ECE-TRANS-WP29-GRSP-2014-05e.pdf.
\134\ TWSG-01-04--ECE-TRANS-WP29-2021-053e, https://unece.org/sites/default/files/2021-02/ECE-TRANS-WP29-2021-053e.pdf.
\135\ In advance of the publication of this NPRM, NHTSA received
a letter from the Alliance for Automotive Innovation (Innovators)
restating support of the interpretation of the GTR 9 that aligns
with the proposed GTR amendment. (The letter can be found in the
docket for this NPRM.) Additionally, in December 2022, NHTSA and the
Innovators met at the latter's request to discuss the same topic. An
ex parte memo documenting this meeting can also be found in the
docket.
---------------------------------------------------------------------------

1. Change to the Amount of Area That Must Comply With HIC1000
One of the main changes proposed by Amendment 3 relates to how the
child headform test area and adult headform test area are defined in
GTR 9. Currently, the GTR 9 combined adult headform test area and child
headform test area are equivalent to the FMVSS No. 228 Hood Area.
Essentially, the new Amendment 3 definitions of adult headform test
area and child headform test area would bring the areas described in
the definitions into alignment with how the Child Headform Test Area
and Adult Headform Test Area are defined in proposed FMVSS No. 228, as
explained in section VI.C of this preamble, i.e., these areas are
defined as being within the 82.5 mm offset lines. However, GTR 9 at
S5.2.3 maintains the requirement that two-thirds of the combined adult
headform test area and child headform test area is required to have a
HIC of 1000 or less. This test area is renamed the bonnet top test
area. Thus, as a result of the Amendment 3 definitional changes, the
amount of HIC1000 area would now be based on a smaller amount of area.
NHTSA has not supported this change because it would reduce the
stringency of the GTR 9 by decreasing the amount of HIC1000 area and
increasing the amount of HIC1700 area.
The agency analyzed a regulatory approach incorporating the aspect
of Amendment 3 related to a reduction of the HIC1000 area. The PRIA
discusses this approach as Alternative 1. This analysis includes a cost
teardown study and assumes the costs associated with meeting the
requirements are similar for a regulatory alternative incorporating
Amendment 3 and the proposed rule. The details of this analysis can be
found in the PRIA for this NPRM. The equivalent life saved (ELS)
estimate and cost per ELS of Amendment 3 compared to the proposed rule
are shown in table VIII.4 below. The monetized benefits and net
benefits of Amendment 3 compared to the proposed rule are shown in
table VIII.5. In comparison to the proposed rule, the equivalent lives
saved under a regulatory alternative incorporating Amendment 3 are
approximately 59% of that under the proposed rule. Under the assumption
that the costs are the same for both the regulatory alternative and
proposed rule, the cost per ELS under Amendment 3 is nearly double that
of the proposed rule. Lastly, net benefits under Amendment 3 are
approximately 55% of the benefits of the proposed rule.

Table VIII.4--Comparison of Cost per Equivalent Life Saved (ELS)
[Millions]
----------------------------------------------------------------------------------------------------------------
Cost Equivalent lives saved Cost per equivalent life saved
Regulatory approach -----------------------------------------------------------------------------------
3% 7% 3% 7% 3% 7%
----------------------------------------------------------------------------------------------------------------
GTR 9 Amendment 3 (PRIA $60.43 48.94 32.28 26.20 $1.87 $1.87
Alternative #1)............
Proposed Rule............... 60.43 48.94 54.87 44.46 1.1.0 1.10
----------------------------------------------------------------------------------------------------------------

Table VIII.5--Comparison of Monetized and Net Benefits for Proposed Rule and Amendment 3
[Millions]
----------------------------------------------------------------------------------------------------------------
Monetized benefits Net benefits
Regulatory option ---------------------------------------------------
3% 7% 3% 7%
----------------------------------------------------------------------------------------------------------------
GTR 9 Amendment 3 (PRIA Alternative #1)..................... $384.51 $312.09 $324.08 $263.15
Proposed Rule............................................... 653.76 529.74 593.33 480.79
----------------------------------------------------------------------------------------------------------------

[[Page 76964]]

2. Change From 3D Method to 2D Targeting Method
The second significant change proposed by Amendment 3 is related to
the targeting method to determine the point on the test surface that is
assigned the HIC value from the impact test. As we stated previously,
NHTSA's proposed method of targeting areas on the hood and assigning
HIC values through the first point of contact is consistent with GTR 9,
and we refer to it as the ``3D Method.'' NHTSA believes GTR 9 is
sufficiently objective using the 3D Method and that Amendment 3 would
not improve the objectivity of the regulation.
We refer to the Amendment 3 suggested method as the ``2D Measuring
Point Method'' or, for simplicity, the ``2D Method'' in the discussion
below. Under the 2D Method, the contact point between the mid-sagittal
plane of the headform and the hood, referred to as the ``measure
point'' in the GTR amendment, serves to define whether HIC1000 or
HIC1700 applies to the particular impact. The ``2D measure point'' is
established prior to a launch and the HIC limit is assigned to that
point. Proponents of the amendment argued that the 2D Method improved
objectivity over the 3D Method because, with the 3D Method, the first
point of contact may be related to multiple lateral headform launch
positions.
To illustrate, figure VIII.1 is a top down and rearward-looking
view of a hood with a sharp bend in the lateral plane. Because of this
sharp transition in the hood profile, it is possible for the headform
impactor to contact the same or nearly the same point (first point of
contact, which in this case is the sharp transition point) for
different launch positions of the headform. However, both the 2D and 3D
Methods will have the same range of headform launch positions that
would result in the first point of contact at the sharp transition.
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[[Page 76965]]

As explained above, in the 2D Method, the 2D measure point on the
hood is established prior to a launch and the pre-test position of the
headform is determined by aligning the mid-sagittal plane of the
headform to that point. Although proponents of the 2D Method argued
that this method of pre-determining the test point on the hood and
assigning the test results to that point improves objectivity of the
test, NHTSA disagrees. For the hood profile shown in figure VIII.1, the
test results for a range of 2D measure points will be associated with
the headform impacting the same hood location (the sharp transition).
NHTSA believes this situation creates ambiguity rather than improves
objectivity because in some instances, the HIC assignment for a point
might not be related to the point being impacted. As illustrated in
figure VIII.1, the HIC values were assigned to points on the slope,
from an impact location further up the slope. In contrast, the 3D
Method is more representative of real-world impacts as it assigns each
test result to its corresponding location of impact (first contact
point) (see figure VIII.2).
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Additionally, in the 3D Method both the lateral pre-test position
of the headform as well as the first point of contact are known, which
enables NHTSA to fully define each test in a compliance
proceeding.\136\ This makes each test objective and highly repeatable.
Thus, we see no reason to favor the 2D Method over the 3D Method based
on claims of improved objectivity.
---------------------------------------------------------------------------

\136\ Manufacturers must certify compliance with any first point
of contact to the require HIC limit for that location, irrespective
of the launch position(s) of the of the headform.
---------------------------------------------------------------------------

NHTSA is also concerned about the safety implications of the 2D
Method.

[[Page 76966]]

The 2D Method can result in a smaller test area, particularly on hoods
that have a downward slope at the sides of the vehicle (See figure
VIII.5). In this figure, the more outboard headform indicates valid
positions that would be tested by the 3D Method. Conversely, the valid
positions tested by the 2D Method are shown by the more inboard
position, where the mid-sagittal plane of the headform aligns with the
HIC Unlimited Margin. As can be seen, the methods used result in
different test area, with the 2D Method decreasing the size of the area
tested. In our own testing of six vehicles of model year 2011 or later,
we observed that the 2D Method moved the impact point further inboard
for five of the six vehicles we tested (and by as much as 46 mm for one
vehicle). As expected, because hood edges are reinforced, HIC scores
were lower when the headform was further inboard. Those data are
consistent with NHTSA testing that has shown that these perimeter
locations may produce higher HIC levels compared to the rest of the
hood.\137\
---------------------------------------------------------------------------

\137\ Details of these tests can be found in: Suntay B and
Stammen, JA (2014), Vehicle hood testing to estimate pedestrian
headform reproducibility, GTR No. 9 test procedural issues, and U.S.
fleet performance
---------------------------------------------------------------------------

Previous real-world studies have shown that many pedestrian head
impacts take place along the hood-fender junction. One study found the
most severe head injuries concentrated towards the outer third of the
hood.\138\ As far back as our 1990 era standards development effort, we
observed an incidence rate of about 20% along the sides.\139\ NHTSA is
not aware of research indicating that this rate has gotten or will get
lower. Thus, NHTSA believes the reduction in safety using the 2D Method
could be significant and has decided not to include the method in this
NPRM.
---------------------------------------------------------------------------

\138\ Koetje B and Grabowski J. A Methodology for the Geometric
Standardization of Vehicle Hoods to Compare Real-World Pedestrian
Crash; Annuals of Advances in Automotive Medicine. 2008; 52: 193-
198.
\139\ An analysis of the potential costs and benefits of
pedestrian head-to-hood impact protection, NHTSA Office of
Regulatory Analysis, NHTSA Docket 91-43, Notice 1, document No. 3,
January 1990. A copy of this document is in the docket for this
NPRM.
---------------------------------------------------------------------------

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[[Page 76967]]

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IX. Headform Characteristics

A. General

The proposed headform impactors are hemispherical and completely
featureless. The mass of the child headform is 3.5 kg and that of the
adult headform is 4.5 kg. During the development of the GTR,
researchers attempted to determine the appropriate ``effective mass''
of the headforms to account for the influence of the neck/torso mass on
the force the head would impart to the hood. The researchers determined
that, averaged over a variety of vehicle shapes, the ``effective mass''
was comparable to the head mass itself.\140\ Thus the masses selected
represent both the ``effective masses'' and actual masses of an average
6-year-old child and a 50th percentile adult male. The mass for a 5th
percentile female head is 3.7 kg.\141\ Using anthropometric data of
adult female head circumference, we can estimate the female head mass
percentile for both the child and adult headform.\142\ The 3.5 kg mass
of the child headform represents a 1st percentile female head mass and
the 4.5 kg mass of the adult headform represents a 64th percentile
female head mass. Thus, these headform masses represent a range of
pedestrian sizes from small children, 64 percent of all female adults,
and up to the average adult male. The effective mass is the

[[Page 76968]]

estimated head mass that is applied to the hood by a struck pedestrian
and includes an allowance for the body force acting through the neck
during the head impact. Effective head mass has been estimated via
laboratory tests with pedestrian dummies and postmortem human subjects
(PMHS), and through mathematical modelling of pedestrian collisions.
---------------------------------------------------------------------------

\140\ Mizuno, Y, Summary of IHRA Pedestrian Safety WG Activities
(2005)--Proposed Test Methods to Evaluate Pedestrian Protection
Afforded by Passenger Cars. ESV 05-0138.
\141\ Schneider, L.W., Robbins, D.H., Pfl[uuml]g, M.A., and
Snyder, R.G. (1983). Anthropometry of Motor Vehicle Occupants:
Development of anthropometrically based design specifications for an
advanced adult anthropomorphic dummy family, Volume 1. Final report
DOT-HS-806-715. U.S. Department of Transportation, National Highway
Traffic Safety Administration, Washington, DC.
\142\ Based on 2007-2010 NHANES from http://tools.openlab.psu.edu/tools/explorer.php. Head mass is assumed to be
proportional to the volume of a sphere with a circumference equal to
the measured head circumference.
---------------------------------------------------------------------------

The diameter of the proposed headforms is 165 mm for both the child
and adult headforms. The average cross-sectional axis of a 6-year-old
child head in the transverse plane at its forehead is about 165 mm
(circumference is 523 mm according to Irwin, 1997).\143\ For an adult,
the head is more elliptical at the forehead cross-section and 165 mm
falls between the breadth (154 mm) and depth (197 mm) of a 50th
percentile male.
---------------------------------------------------------------------------

\143\ Irwin A and Mertz HJ (1997), Biomechanical basis for the
CRABI and Hybrid III child dummies, 41st Stapp Car Crash Conference,
1997.
---------------------------------------------------------------------------

Each headform would have three parts: an aluminum hemisphere, a
synthetic covering, and an end plate. The main hemisphere of each
headform is hollowed out to eliminate internal corners and mitigate
low-frequency resonance. The lighter hemisphere has a deeper cavity to
achieve the same 165 mm diameter as the heavier, adult headform. Both
the proposed child and adult headforms have vinyl coverings and the
headforms and coverings together are designed to achieve a specific
system response.
The proposed headform end plates are bolted onto the hemisphere and
hold the synthetic coverings in place. This NPRM specifies the material
and dimensions of the end plates. A triaxial arrangement of
accelerometers is mounted on the inner surface of each end plate such
that they are located at the centroid of the headforms.
Each combination of hemisphere, synthetic covering, and end plate
(including accelerometers and their mount blocks) would assure that the
center of gravity of the complete headform is coincident with the
geometric center of the spheroid (i.e., the centroid) while attaining a
moment of inertia that is representative of a 6-year-old child (for the
child headform) and a 50th percentile adult male (for the adult
headform).
A complete set of drawings for each headform is provided as part of
the regulatory text of proposed FMVSS No. 228 in figures 13-27. The
drawings are, to NHTSA's knowledge, consistent with the current
production of two known manufacturers of headforms that the agency has
used in testing and evaluation described in section IX.C .\144\ In some
cases, dimensions have been purposefully made ``reference'' dimensions
to facilitate flexibility in producing headforms such as those
evaluated headforms. GTR 9 does not provide this level of specificity
and only provides headform schematics such as are included in figures
11 and 12 in the proposed regulatory text. Contrary to that approach,
the agency believes there is benefit to providing more detailed drawing
dimensions, as we have done in figures 13-27. These detailed drawings
should allow any entity wishing to produce a headform that can be used
in FMVSS No. 228 to simply meet the provided dimensions. However,
consistent with GTR 9, the notes provided on the headform drawings
specify that headform dimensions may be modified as long as a set of
specifications of the drawings is met. These specifications pertain to
the impactor mass, diameter, skin material and thickness, center of
gravity, moment of inertia, accelerometer mounting, accelerometer
damping, qualification limits and natural frequency. The agency
requests comment on the approach taken with the headform drawings.
Should the agency take an even more prescriptive approach than has been
proposed or should it take a less prescriptive approach similar to GTR
9?
---------------------------------------------------------------------------

\144\ Humanetics Corp., Farmington Hills MI, formally FTSS, and
Cellbond, Huntingdon, United Kingdom.
---------------------------------------------------------------------------

B. Qualification Limits

This NPRM proposes a set of pre-test qualification limits to ensure
the headforms are functioning properly.\145\ The qualification tests
are also intended to assure that the impact responses of the headforms
are uniform. NHTSA's regulation for anthropomorphic test devices (49
CFR part 572) specifies qualification tests and limits for all
anthropomorphic test devices (ATDs) used in the FMVSSs.
---------------------------------------------------------------------------

\145\ ``Qualification limits'' set parameters to ensure test
devices are functioning properly. Test devices (e.g., headforms) are
subjected to a prescribed test protocol and are deemed acceptable if
they provide measurements within the qualification limit. If the
qualification limits are not met, the agency will adjust the device
(headform) until the qualification limits are met or discard the
device (headform), deeming it insufficiently reliable for use in a
compliance test. A ``narrowing'' of the qualification limit means
that less variation in the performance of the test devices at issue
would be acceptable to NHTSA compared to a qualification limit that
had a wider tolerance as to acceptable performance.
---------------------------------------------------------------------------

The proposed qualification tests are headform drop tests. The
proposed qualification requirements are based on the peak resultant
acceleration measured within the headform in the qualification test.
The test apparatus is shown in figure 12 of proposed FMVSS No. 228,
infra.
The proposed apparatus and procedure have been adapted from those
used to qualify the headforms of ATDs specified in 49 CFR part 572. The
proposed test for the child headform was adapted from the test used for
the Hybrid III 6-year-old child dummy (part 572, subpart N), while the
proposed test for the adult headform was adapted from the test for the
Hybrid III 50th percentile adult male (part 572, subpart E). In the
proposed tests, the headform is suspended at a height of 376 mm and a
drop angle of 50 degrees and 65 degrees, with respect to the vertical,
for the child and adult headforms, respectively.
For each pedestrian headform, there would be qualification tests
consisting of three head drops with the headform rotated 120[deg]
around its symmetrical axis after each drop. We propose that the
resultant acceleration of the child headform must fall between 245-300
g's for drops at each rotation. For the adult headform, the proposed
limits are 225-275 g's. The limits are the same as those currently in
part 572 for headform qualification of the Hybrid III 6-year-old child
and Hybrid III 50th percentile adult male test dummies. These G-limits
represent 10 percent of the midpoint of data obtained from
headform drops in tests conducted for the Hybrid III 6-year-old and
50th percentile adult male dummies. In addition, we propose
requirements for off-axis sensitivity and a unimodal response, as well
as a protocol to clean the headform prior to qualification testing to
improve repeatability. These factors are in addition to GTR 9
specifications and are based on NHTSA's years of testing and qualifying
headforms. They would be consistent with other part 572 headform
requirements.

C. Repeatability and Reproducibility

The headforms have been shown to produce repeatable and
reproducible results. Repeatability is defined as the similarity of
responses from a single headform when subjected to multiple repeats of
a given test condition. Reproducibility is defined as the similarity of
test responses from multiple headforms when subjected to multiple
repeats of a given test condition. NHTSA assessed the repeatability and
reproducibility (R&R) of the headforms in qualification drop tests and
actual hood tests.
1. Headform Drop Tests
In headform drop tests, we assessed the R&R of child and adult
headforms

[[Page 76969]]

manufactured by two different manufacturers, Cellbond and FTSS.\146\ As
part of this assessment, we also varied the type of accelerometer
installed within the headform. We ran two sets of qualification tests
with the Cellbond headforms: one with damped accelerometers and one
with undamped accelerometers. One set of tests was run with the FTSS
headforms, fitted with undamped accelerometers. All acceleration
responses were filtered at Channel Filter Class (CFC) 1000. The
responses are summarized in table IX.1, including averages, standard
deviations, and percent coefficients of variation (%CV). The %CV is
computed by dividing the standard deviation by the average (and
multiplying the result by 100 percent). The results are similar for
both headform manufacturers and for both accelerometer types.
Typically, NHTSA strives for a %CV of less than 5 percent, so the low
%CV observed in our tests indicates a high degree of repeatability and
reproducibility by our measure and is well within an acceptable
interval.
---------------------------------------------------------------------------

\146\ Suntay B and Stammen, JA (August 2018), Vehicle hood
testing to estimate pedestrian headform reproducibility, GTR 9 test
procedural issues, and U.S. fleet performance. Docket NHTSA-2008-
0145-0014.

Table IX.1--Qualification Drop Tests: Peak Resultant Acceleration (and HIC Scores) of Headforms
----------------------------------------------------------------------------------------------------------------
Peak acceleration, g (HIC score in parentheses)
Headform (compliance interval, Statistical ---------------------------------------------------------------
g) measure Cellbond Cellbond FTSS
(damped) (undamped) (undamped) Combined
----------------------------------------------------------------------------------------------------------------
Child (245-300)............... Average......... 257 (871) 258 (851) 262 (904) 259 (876)
StdDev.......... 4.36 (3.00) 1.00 (19.35) 9.07 (46.32) 5.62 (34.21)
%CV............. 1.7% (0.3%) 0.4% (2.3%) 3.5% (5.1%) 2.2% (3.9%)
Adult (225-275)............... Average......... 238 (779) 237 (758) 235 (766) 237 (768)
StdDev.......... 5.57 (16.82) 3.06 (17.58) 1.15 (11.36) 3.57 (16.26)
%CV............. 2.3% (2.2%) 1.3% (2.3%) 0.5% (1.5%) 1.5% (2.1%)
----------------------------------------------------------------------------------------------------------------

The headforms were dropped from a height of 376 mm, which is the
height specified in GTR 9 and the height used in other part 572
headform qualification tests. However, we are considering raising the
drop height. Typically, in NHTSA's practice an ATD qualification
procedure exercises the ATD near the pass/fail reference measure. In
this case, the HIC scores obtained from the 376 mm drop are slightly
below the HIC1000 limit proposed for the pedestrian headform
requirement, and well below the HIC1700 requirement. (Average HIC
produced by the 376 mm drop are 876 for the child headform, and 768 for
the adult headform). Therefore, we request comments on raising the drop
height to a height that would produce HIC scores somewhere between 1000
and 1700.
We also request comments on changing the qualification bounds of
245-300 g's for the child headform and 225-275 g's for the adult
headform. For other ATDs used in FMVSSs, we generally set qualification
bounds by examining data from multiple test labs, several ATDs, and
ATDs built by different manufacturers. In other words, the
qualification bounds are derived from the qualification data, not set a
priori, with a goal to set them at no greater than 10 percent of the
mean.
We understand that the qualification bounds of GTR 9 were set a
priori, by using the qualification limits of part 572 as a basis for
the bounds. While this would be acceptable given that the part 572
bounds have worked satisfactorily historically, our results suggest
that those pre-existing headform qualification limits could be narrowed
for both of the pedestrian headforms. The part 572 headform
qualification limits were developed for the Hybrid III head, but the
hemispherical headforms specified in this NPRM are much more
geometrically uniform. For the pedestrian headforms, the acceptance
bounds of 25 g's (for the adult headform) and 27.5 g's (for the child headform) are both derived using the 10
percent approach. In part 572, NHTSA has generally sought to set
qualification limits for a test device within 10% of a
nominal target, usually the mean response from all relevant data
available about a test device gathered from agency research,
commenters' submissions and other means. The 10% margin is
considered wide enough to account for normal variations in response and
laboratory differences, and narrow enough to ensure consistent and
repeatable measurements in standardized testing. However, both sets of
bounds represent well over three standard deviations from the mean
based on the test data shown in table IX.1. From a probabilistic
standpoint, three standard deviations constitute an unusually wide
bound.
Since the publication of the headform evaluation report, NHTSA
Vehicle Research and Test Center (VRTC) has continued to conduct many
more headform qualification tests to support vehicle impact testing.
This updated dataset provides a significantly greater number of samples
from a much larger number of headforms. These data can be used to
better determine whether the current GTR 9 qualification bounds are
appropriate and sufficient, rather than using only the data from table
IX.1. Table IX.2 summarizes this updated dataset.

Table IX.2--Updated NHTSA Data From Headform Qualification Tests
[Peak resultant acceleration]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Child headform (12 headforms subjected to 60 Adult headform (12 headforms subjected to 60
total tests) total tests)
Headform orientation ------------------------------------------------------------------------------------------------
Standard Standard
Average deviation %CV Average deviation %CV
--------------------------------------------------------------------------------------------------------------------------------------------------------
0 deg.................................................. 275 16.7 6.1 252 12.1 4.8
120 deg................................................ 272 14.7 5.4 251 13.0 5.2

[[Page 76970]]

240 deg................................................ 274 16.6 6.1 250 13.0 5.2
All.................................................... 273 15.8 5.8 252 12.1 4.8
--------------------------------------------------------------------------------------------------------------------------------------------------------

The average responses are almost exactly in the middle of the GTR
specification for a large number of headforms and tests, and the
current GTR 9 tolerance of 10% closely approximates two
standard deviations for both headforms (slightly less for the child
headform and slightly more for the adult headform). Based on this
information, the FMVSS No. 228 proposal retains the GTR specification
rather than providing an alternative specification unique to NHTSA.
While the data shown in table IX.2 constitute a substantial set of
120 data points from 24 different headforms, our tests were conducted
at a single laboratory (NHTSA's Vehicle Research and Test Center) with
headforms from three headform manufacturers.\147\ Our data may not
reflect normal variations that accrue when a large set of headforms are
tested across various laboratories. There may be unknown variability
associated with different labs, operators, headforms, and other typical
variances such as temperature and humidity, that may not be present in
our dataset.
---------------------------------------------------------------------------

\147\ Table IX.1 contains headform data from two manufacturers,
while table IX.2 contains headform data from three manufacturers.
---------------------------------------------------------------------------

Thus, although we have used the conservatively wide bounds from
part 572 in the proposed regulatory text for this NPRM, we seek
qualification data from commenters. We will examine all qualification
data provided and anticipate that, when new qualification data are
combined with our current set of data, the bounds could be tightened,
such as to one standard deviation or less. For a final rule, our intent
is to set bound widths as narrowly as is reasonable to control
variability to the extent possible.
We note that a comparison of qualification results for Cellbond vs.
FTSS headforms used in our research programs did show some differences.
In qualification tests, Cellbond and FTSS headforms were essentially
equivalent in terms of the peak acceleration they measured, but HIC
scores differed between the FTSS and Cellbond child headform by about
5%. Also, a phase difference in the signal response appears evident,
with the Cellbond units producing peaks in acceleration that occur
about 0.5 ms earlier in both the adult and child headforms. However, as
discussed below, the FTSS and Cellbond headforms are essentially
equivalent when considering the HIC scores produced by hood impacts.
2. Headform Performance in Hood Testing
We also assessed the performance of the headforms in tests on
actual hoods. The Cellbond and FTSS headforms were evaluated on three
vehicle models: the 2010 Kia Forte, the 2010 Buick LaCrosse, and the
2010 Acura MDX. We also used different types of accelerometers to
assess the effect of damped versus undamped models. (Although these
vehicle models are now more than a decade old, the results and
conclusions are still valid as they relate to how the headforms
performed relative to an actual hood. The assessment was done in the
2012-2014 timeframe on new hoods. The vehicles were selected to provide
a cross-section of vehicle manufacturers, vehicle classes and hood
contours.)
We selected three test points in areas on the hood where HIC was
expected to exceed HIC1000 and approach HIC1700. In other words, we
exercised the headforms near the proposed HIC performance thresholds.
The three points were: an inboard point along the WAD1000 border (near
the front edge of the hood); a point just inside the HIC Unlimited
Margin of the Side Reference Line (near the fender); and an inboard
point near the Rear Reference Line (near the rear edge of the hood).
We conducted tests at all three points with one headform brand/
accelerometer combination before switching to another. Each time a
headform switch was made, a new hood was installed. For each vehicle,
the impact points were tested in the same order. The order of headform
use was: (1) FTSS (undamped accelerometers); (2) Cellbond (damped
accelerometers); and, (3) FTSS (damped accelerometers). The hoods of
the Forte and the LaCrosse were sufficiently short that only child
headforms were used. Child and adult headforms were used on the Acura
MDX.
Qualification tests were performed on each headform before and
after the test series to ascertain the accuracy of their measurements.
The headforms met all of the qualification response requirements, both
before and after the tests.
We note that when comparing tests at the same test point on
different samples of the same hood, the data also represent differences
that may exist due to production variability of the hood itself.
Without extensive testing of many copies of a particular hood, it was
not possible for NHTSA to separate this production variability from
that of the headform and test procedure. HIC results are presented
table IX.3 for the three vehicles tested.
BILLING CODE 4910-59-P

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[GRAPHIC] [TIFF OMITTED] TP19SE24.028

BILLING CODE 4910-59-C
2010 Buick Lacrosse. For the Buick LaCrosse, the HIC variability
was less than 10 percent at all three points. Notably, tests at two of
the points produced HIC scores near the HIC1000 and HIC1700 thresholds,
and the third produced an average HIC score near 650. This demonstrates
a high level of repeatability when test results are near the pass-fail
compliance thresholds. It also demonstrates that the various headform
and accelerometer combinations performed in a functionally equivalent
manner.
2010 Kia Forte. For the Kia Forte, one test point, near the fender,
produced HIC scores near a compliance threshold. HIC scores were just
below the HIC1700 threshold, and the variability was very low--less
than 4 percent.
At the two other points (near the WAD1000 border and the rear HIC
Unlimited Margin), variability was over 10 percent. However, at both
points the HIC scores were well below HIC1000. In addition, we note
that for lower HIC values, a similar absolute difference in HIC value
represents a higher

[[Page 76972]]

percentage of the HIC level. In other words, the CV% is artificially
high because the denominator (average HIC) is low--not so much that the
variability in repeated impacts is excessive.
2010 Acura MDX. At each of the three test points, HIC variability
was 10 percent or higher. However, we believe that factors may have
increased the variability. During the tests at the WAD1700 border (and
near to the hood hinge), we observed fender deformation that took place
during the course of testing. (Use of the heavier adult headform may
have caused the deformation.) The damage occurred within the body
structure, not on the hood itself, and was not repaired or replaced
between tests. The deformation could have lowered the HIC of a
subsequent test and contributed to the variability in HIC scores.
Also, in the test with the FTSS-damped headform run near the HIC
Unlimited Margin of the Leading Edge Reference Line, there was a spot
weld separation within the hood structure where an inner layer of sheet
metal was mated to the bottom side of the outer layer. The test had a
HIC of 969. No separation was observed in the other two tests, which
had more comparable HIC scores (1283 and 1324).\148\
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\148\ We do not believe the 2010 Acura MDX was designed in
accordance with GTR 9 requirements. The 2010 Acura MDX was produced
in Canada, and to our knowledge, was not sold in Europe.
---------------------------------------------------------------------------

3. Reproducibility in Hood Testing
The results of the hood testing program also demonstrated good
reproducibility of the headforms' measurement of HIC.\149\ The results
in table IX.3 show that FTSS and Cellbond headforms are essentially
equivalent when considering the HIC scores produced by hood impacts in
which test conditions were otherwise identical.
---------------------------------------------------------------------------

\149\ This conclusion is based only on tests on the Kia and
Buick since variability was observed in the way the hood of the
Acura MDX deformed.
---------------------------------------------------------------------------

We analyzed HIC scores produced by child headforms fitted with
Endevco model 7264G damped accelerometers. For the six pairs of tests
considered, the variability was no greater than 7 percent in any of the
paired tests. Also, there was no apparent trend in which one headform
produced higher HIC scores than the other. For four of the test points,
the lowest HIC score was produced by the FTSS unit. In the other two,
the Cellbond scores were lowest. We did observe that the FTSS child
unit had relatively high variability for HIC (Standard Deviation = 46),
but not peak acceleration. Adult headforms had much lower variability
for all conditions.
4. Instrumentation
Proposal for Damped Accelerometers
This NPRM proposes a specification for damped accelerometers in the
headforms. Although the GTR does not refer specifically to damped \150\
accelerometers, the preamble to the GTR recommends damped
accelerometers based on findings from a 2002 research program using
2001 headform data collected for the Japan New Car Assessment Program
(J-NCAP). In headform tests with undamped accelerometers, abnormal
signals that produced high HIC values were observed in windshield
impacts \151\ and occasionally in hood impacts. The cause of the
abnormality was attributed to vibrations that arose when the impulse of
the impact was near the resonant frequency of the
accelerometer.^{152 153}
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\150\ In general, damped accelerometers are used when shock
pulses of extremely short durations occur in a test environment that
would otherwise induce resonance in the sensor.
\151\ The windshield is no longer included within the test area
prescribed by the GTR.
\152\ Informal document no. GR/PS/96, Problem of undamped
accelerometer in headform impact test. 7th meeting of the pedestrian
safety informal working group, Paris, France, September 28, 2004.
\153\ Informal document no. GR/PS/133, Miniature Damped
Accelerometer Series, 8th meeting of the pedestrian safety informal
working group, Brussels, July 11, 2005.
---------------------------------------------------------------------------

NHTSA's testing has been with undamped accelerometers. The testing
and findings are described in section IX.C.5.c, below. We did not
observe any signal irregularities of the sort observed in the J-NCAP
study. We did observe a difference in peak measurements depending on
the type of accelerometer (they were generally lower with damped
units). In vehicle tests, these sharp pulses occur when hard metal-to-
metal contacts or mechanical fractures take place. If an accelerometer
is attached directly to a vehicle structure (such as the frame rail),
the sharp pulse can often saturate the measurement system. However,
ATDs such as crash test dummies are designed to avoid internal
mechanical fractures or metal-to-metal contact that could produce sharp
pulses. Therefore, undamped accelerometers are typically specified for
ATDs used in FMVSSs.\154\
---------------------------------------------------------------------------

\154\ Also, pedestrian headforms, with their synthetic
coverings, when used on the hood do not engage in metal-to-metal
contact, nor do the hollowed aluminum hemispheres incur internal
mechanical fractures.
---------------------------------------------------------------------------

Nonetheless, although we saw no resonance issues in our tests with
ATD heads fitted with the undamped units, we propose damped
accelerometers for the pedestrian headforms. We envision using the same
headforms in NCAP where the test protocol includes potential testing of
the windshield, cowl, and A-pillar. When testing such areas, the
uncovered rear portion of the headform may come into contact with a
vehicle structure such that an undamped accelerometer may produce a
spurious signal and invalidate a test, similar to what was observed in
J-NCAP testing. We request comment on the proposed use of damped
accelerometers and whether it would be more appropriate to use an
undamped accelerometer in proposed FMVSS No. 228, as is used in part
572 ATD heads.
This NPRM also proposes to specify the performance of the
accelerometers in accordance with SAE J211/1_202208 (2022),
``Instrumentation for Impact Test Part 1--Electronic Instrumentation,''
in lieu of what GTR 9 references, which is ISO 6487 (2002),
``Measurement Techniques in Impact Tests.'' SAE J211 and ISO 6487 are
essentially equivalent. SAE J211 is the most current of the two, and
FMVSSs have historically referenced SAE J211, not the ISO standard. For
those reasons, we propose to reference the current version of SAE J211
in proposed FMVSS No. 228.\155\
---------------------------------------------------------------------------

\155\ This NPRM proposes to amend 49 CFR 571.5 to add SAE J211
(2022) to the list of material incorporated by reference in the
Federal motor vehicle safety standards.
---------------------------------------------------------------------------

5. Technical Assessment
a. Hood Impact Tests
In our test program assessing the performance of the Cellbond and
FTSS headforms on the 2010 Kia Forte, the 2010 Buick LaCrosse, and the
2010 Acura MDX (results above), we also used different types of
accelerometers to assess the effect of damped versus undamped models.
We examined our headform test signals for any indication of resonant
vibrations and examined any differences in responses depending on
whether damped or undamped accelerometers were used.\156\
---------------------------------------------------------------------------

\156\ In our examination of hood impact tests, we considered
tests run only on the Buick and Kia because we observed variability
in the way the hood of the Acura MDX deformed.
---------------------------------------------------------------------------

At each of the six test points (three on the Buick, three on the
Kia), one test was run with undamped units (in an FTSS headform) and
two were run with damped units (one each for the FTSS and Cellbond
headforms). The highest HIC score was recorded with the undamped (FTSS)
unit for five of the six test points, with a percent difference ranging
from 3 percent to 19 percent higher. For the other test point, all
three HIC scores were nearly the same (less than 3 percent difference).
We also checked the test signals (figure IX.1) in all tests with
undamped accelerometers and did not observe any

[[Page 76973]]

spurious signals to indicate that resonance frequencies had been
reached. The undamped Endevco units that we used (model 7264C) had a
resonant frequency rated at >26,000 Hz, which is extremely high
relative to the impulses typical of headform-to-hood impacts. We note
that the natural frequency of the headform itself is much lower,
specified as >5,000 Hz in the GTR. Thus, the root cause of resonance
observed by J-NCAP might have been ringing of the headform at a
relatively low frequency, rather than excitation of the accelerometer
at its rated (higher) frequency.
[GRAPHIC] [TIFF OMITTED] TP19SE24.029

b. Qualification Tests
We examined our qualification head drop signals for differences in
responses depending on whether damped or undamped accelerometers were
used. (This comparison was carried out for the Cellbond units only). We
did not observe any consistent difference between accelerometer types.
The magnitude in the peak acceleration was about the same for both.
Also, we did not observe any perceptible phase shift.

X. Other Issues

A. Active Hoods

An active hood uses actuators and lever arms to automatically lift
the hood when a sensor detects that a pedestrian has been struck by the
front-end of the vehicle. The system acts to pre-position the hood
before the secondary (head) impact takes place with an oncoming
pedestrian. In doing so, space is created between the hood and rigid
components in the engine bay, thus reducing the risk of injury to the
pedestrian. Compared to non-deploying hoods, active hoods offer the
potential to greatly increase the free penetration space underneath the
hood. They may be especially advantageous because they create extra
space in the cowl area where pedestrian head strikes to the hood are
most apt to take place. NHTSA testing indicates that, historically, the
rear of the hood near the cowl has included stiff structures, giving
HIC values close to or above 1700, especially in areas near the hinges
at the rear corners of the hood and around the wiper mounts. For
vehicles with non-deploying hoods, the cowl usually lies rearward of
the HIC Unlimited Margin of the Rear Reference Line. A HIC1700
relaxation area is typically allocated to the Adult Headform Test Area
adjacent to the margin.
FMVSS No. 228 would include provisions in the compliance test
procedure that provides for deployment of active hoods.\157\ Consistent
with GTR 9, this NPRM's regulatory text specifies that NHTSA will
deploy an active hood in accordance with manufacturer instructions
prior to launching the headform, including the irrevocable selection of
the minimum and maximum period of time between device deployment and
the impact of the headform to assure full deployment at impact. The
proposed regulatory text does not set the conditions under which the
active hood must activate, the timing of their activation and
deployment, or provide performance criteria testing that the sensor
works as intended. However, we have included a provision in the
standard that would require manufacturers to, upon request and under
the authority provided in 49 U.S.C. 30166 (NHTSA's enforcement
authority), provide information to NHTSA explaining the basic
operational characteristics of their active hood sensor system.\158\
---------------------------------------------------------------------------

\157\ GTR 9 does not directly address active hoods except to
note that active hoods and other active safety devices ``must not
create a higher risk of injuries for the pedestrians,'' (United
Nations (18 November 2004). Global technical regulation No. 9:
Pedestrian Safety [Addendum to GTR] Geneva, Switzerland. Page 28,
section A.8.b.122, and that ``[a]ll devices designed to protect
vulnerable road users when impacted by the vehicle shall be
correctly activated before and/or be active during the relevant
test. It shall be the responsibility of the manufacturer to show
that any devices will act as intended in a pedestrian impact.'' Id.,
page 50, section B.6.2.2.
\158\ This provision is similar to that in FMVSS No. 226,
``Ejection mitigation,'' regarding the sensor system and pertinent
inputs to the algorithm used to determine when a side curtain will
deploy in a real world rollover.
---------------------------------------------------------------------------

Under FMVSS No. 228, the point of first contact between the
headform and the hood would be determined while the hood is fully
deployed. However,

[[Page 76974]]

consistent with the GTR, the standard's test procedure would specify
that the borders and test areas are marked off when the hood is in its
normal, undeployed position as with a conventional hood. This is for
practical reasons. Obviously, the agency is not able to mark off the
hood when the hood is in a dynamic, moving state. We understand that
the hood could be fixed in some deployed position. However, the current
mark off method may not lend itself to the deployed surface and the
transitions between the deployed hood and the fixed hood/fender areas
without appropriated modification. Finally, the agency has not yet
researched the implications of marking off a hood fixed in a deployed
position.
NHTSA believes there are very few recent vehicles in the U.S.
vehicle fleet with active hood designs. Therefore, data on their
performance are limited. According to a 2014 survey of European sales
data, only about 8% of new light vehicles sold in Europe had active
hoods. North American variants of those models make up about 7% of
light vehicle sales in the U.S.\159\
---------------------------------------------------------------------------

\159\ Ames E., Martin P. ``Pop-up Hood Pedestrian Protection,''
24th Enhanced Safety of Vehicles, paper 15-0111 (2015).
---------------------------------------------------------------------------

In general, vehicles with active hoods performed better than
vehicles without active hoods in Euro NCAP tests. To date, NHTSA's
research program has tested four vehicles equipped with active hood
systems. Two of these vehicles (2014 Cadillac ATS, 2017 Audi A4) were
U.S. variants retrofitted with European active hood components.\160\
The reduction in HIC observed with the hood fully deployed was much
greater for the Cadillac than for the Audi. However, NHTSA believes
this difference reflected the vehicles' baseline performance when the
hood is undeployed. More recently, NHTSA identified two U.S. market
vehicles (2018 Buick Regal, 2021 Volkswagen Arteon) that have active
hood systems. The HIC reduction observed in testing those vehicles with
the hood fully deployed versus not deployed varied widely by vehicle
and impact location.\161\ At impact points already with low HIC without
hood deployment, HIC reduction was minimal when an active hood was
employed, while at stiffer impact points, hood deployment did improve
performance substantially in many instances.
---------------------------------------------------------------------------

\160\ Suntay B, Stammen J. ``Assessment of Hood Designs for
Pedestrian Head Protection: Active Hood Systems,'' DOT HS 812 762
(2020).
\161\ Suntay B, et al. ``Vehicle Assessment using Integrated
Crash Avoidance and Crashworthiness Pedestrian Safety Test
Procedures'' DOT HS 813 521.
---------------------------------------------------------------------------

Based on these test results, the safety benefit relative to the
cost of implementing an active hood system may not be significant for
some vehicles. However, there is still reason to believe that these
types of systems may become more common in the U.S. market because it
may be a viable design solution for some vehicles to meet the proposed
pedestrian protection requirements. Therefore, NHTSA is considering
developing a set of compliance test requirements to assure the proper
deployment and function of active hoods. For example, we would like to
consider the appropriateness of requirements for the lift mechanisms to
assure that they do not collapse inappropriately under the full body
weight of a pedestrian. We seek comment and data on the real-world
performance and proper function of active hood systems observed in the
E.U. and elsewhere. We request information to shed light on the
reliability of the systems, including information on the rate of false-
positive deployments. We are interested in learning more about the
consequences to pedestrians if a collision occurs below the hood
activation threshold. Would a pedestrian be placed in undue risk if the
undeployed hood is overly stiff? Should there be HIC limits in headform
impact tests on an undeployed hood to ensure HIC values are not too
high (e.g., HIC values must be less than 1350) \162\ when a test is
conducted at a designated deployment threshold speed?
---------------------------------------------------------------------------

\162\ A HIC1350 limit is used in Euro NCAP in tests of this
condition. We request comments on the merits of the HIC1350
threshold.
---------------------------------------------------------------------------

XI. Effect on Other Standards

NHTSA has examined the potential effect of this NPRM on other
Federal motor vehicle safety standards and programs. As discussed
below, the agency has determined that FMVSS No. 228 would not affect
the ability of a vehicle to meet all other FMVSS applying to the
vehicle. We request comment on our conclusions. Vehicles in the U.S.
already have hoods that meet GTR 9, which indicates the compatibility
of the GTR (and proposed FMVSS No. 228) with applicable FMVSSs.
Further, GTR 9 has been implemented by Contracting Parties worldwide
that have standards that are similar to many of those discussed below,
which also show how pedestrian protective hoods meeting FMVSS No. 228
could be integrated into vehicle designs.
Safety Standards
FMVSS No. 104, Windshield wiping and washing systems, specifies
requirements for windshield wiping and washing systems. FMVSS No. 228
would not affect the performance of the windshield wiping and washing
systems, as the ``hood area'' subject to FMVSS No. 228 would preclude
the area in which the systems are located.\163\ If manufacturers would
like to opt for designs where windshield wiper arms are hidden or made
softer or deformable to better protect pedestrians, FMVSS No. 228 would
not preclude such designs.
---------------------------------------------------------------------------

\163\ NHTSA has requested comment in this NPRM on extending the
testable area to the windshield. The NCAP RFC and Euro NCAP
procedures test the windshield and the wiper and washing system
area.
---------------------------------------------------------------------------

FMVSS No. 108, ``Lamps, reflective devices and associated
equipment,'' would not be affected by this proposed standard as the
relevant equipment covered by Standard No. 108 would generally be
outside of the hood area. Yet, if pop-up style headlights are in the
hood area and are subject to headform testing, FMVSS No. 228 would
require the vehicle to meet the tests when the lights are both deployed
and in their stowed position. This is to optimize pedestrian protection
in the real world, as an impact could occur when the movable lights are
deployed and when they are stowed.
FMVSS No. 208, ``Occupant crash protection,'' is intended to reduce
the number of deaths of vehicle occupants, and the severity of
injuries, by specifying vehicle crashworthiness requirements in terms
of forces and accelerations measured on anthropomorphic dummies in
frontal crashes, and by specifying equipment requirements for active
and passive restraint systems. FMVSS No. 228 would not interfere with a
manufacturer's ability to meet FMVSS No. 208, because the vehicle
structures related to occupant protection in general and frontal
crashes in particular, should be substantially unaffected by any
redesign needed for pedestrian head protection.
FMVSS No. 113, ``Hood latch system,'' requires that a front opening
hood must be provided with a second latch position on the hood latch
system. FMVSS No. 228 would not interfere with a vehicle's compliance
with FMVSS No. 113 because vehicles are already manufactured to meet
FMVSS No. 113 and the requirements of GTR 9 (and by implication, the
proposed requirements of FMVSS No. 228).
FMVSS No. 401, ``Interior trunk release,'' requires a trunk release

[[Page 76975]]

mechanism to enable a person trapped inside the trunk compartment of a
passenger car to escape from the compartment. If the trunk is located
in the front of the vehicle, the trunk lid would be subject to FMVSS
No. 228. The agency believes that there is no conflict between
providing a trunk (which is the hood, when located in front) release
and FMVSS No. 228. The release mechanism would be similar to existing
hood releases, except it would have a control inside the trunk.
FMVSS No. 219, ``Windshield zone intrusion,'' provides that a
vehicle's hood must not enter a defined zone in front of the vehicle's
windshield during a frontal barrier crash test at 48 km/h (30 mph). The
purpose of the standard is to reduce injuries and fatalities that
result from occupant contact with vehicle components, such as the hood,
that are displaced into the occupant compartment through the windshield
or into the zone immediately forward of the windshield aperture during
a frontal crash. NHTSA concludes that FMVSS No. 228 would not interfere
with a vehicle's compliance with FMVSS No. 219, as vehicles are already
manufactured that meet FMVSS No. 219 and the specifications of proposed
FMVSS No. 228.
FMVSS No. 127 Pedestrian Automatic Emergency Braking (PAEB)
NHTSA plans for proposed FMVSS No. 228 to work with FMVSS No. 127
which includes a requirement for pedestrian automatic emergency braking
(PAEB). PAEB safety systems are designed to stop the vehicle
automatically before striking a pedestrian up to a certain speed or
reduce the speed at which an impact occurs if the vehicle's initial
speed is too high to avoid impact. More specifically, the target
population for proposed FMVSS No. 228 was adjusted downward by
anticipating the potential benefits of FMVSS No. 127. We also note that
it is possible that there may be additional fatalities and non-fatal
injuries that would fall into the target population potentially
addressed by FMVSS No. 127 in cases that PAEB results in crash
mitigation rather than avoidance. That is, for many impacts that cannot
be avoided due to the closing speed of the vehicle, PAEB will lower the
vehicle's speed so that more impacts will be at speeds of 40 km/h (25
mph) or less, which are pedestrian impacts that this proposed FMVSS No.
228 pedestrian head protection standard addresses. For these impacts
FMVSS No. 228 would ensure the striking vehicles have features that
protect against serious to fatal head injury in these impacts. Due to
data limitations, however, we are unable to estimate the number of
additional fatalities and non-fatal injuries that may be potentially
addressed by proposed FMVSS No. 228 following the adoption of FMVSS No.
127.
49 CFR Part 581, ``Bumper Standard''
49 CFR part 581, issued under the Cost Savings Act,\164\ applies to
passenger cars. It specifies a set of vehicle bumper tests designed to
reduce physical damage to the front and rear ends of a passenger motor
vehicle from low speed (2.5 mph) collisions. NHTSA does not believe
there is an incompatibility between the bumper standard and this NPRM.
The proposed rule would not have a direct effect on the bumper area of
vehicles.
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\164\ The Motor Vehicle Information and Cost Savings Act, 49
U.S.C. 325, provided for promulgation of bumper standards to reduce
the economic loss resulting from damage to passenger motor vehicles
involved in motor vehicle crashes.
---------------------------------------------------------------------------

Fuel Economy Standards
As explained below in the Benefits and Costs section of this
notice, the costs associated with this proposal are assumed to be based
on increased weight and its effect on fuel economy. See table XIII.2
for a breakdown of the estimated costs.
New Car Assessment Program
FMVSS No. 228, if adopted, would lay the regulatory foundation for
NHTSA's adopting a crashworthiness pedestrian protection component into
NHTSA's New Car Assessment Program (NCAP), as laid out in the May 26,
2023 NCAP RFC, supra. NCAP would build on proposed FMVSS No. 228 and
incorporate enhanced crashworthiness tests into the consumer
information program. The NCAP RFC proposes adding the majority of Euro
NCAP's injury assessment scheme for head and leg test devices and the
method in which scores for each impact point are calculated. These Euro
NCAP tests correspond closely to those in GTR 9.
There are important differences, however, between FMVSS No. 228 and
the NCAP RFC. While both mark off the Hood Top in a similar way and the
impactors used for testing are the same, the final test areas differ,
as do the outcomes of the tests (FMVSS No. 228 would have pass/fail
criteria while NCAP would determine specific scores at each test
point). The NCAP RFC test area is larger than the FMVSS No. 228 test
area due to the HIC Unlimited Area on the sides of the Hood using a 50
mm offset (NCAP RFC) rather than the 82.5 mm Offset Line (FMVSS No.
228). In section VI.C of this preamble, we requested comment on
modifying the final rule offset to 50 mm.
Additionally, on the front boundary of the test area, the NCAP RFC
does not utilize an 82.5 mm Offset Line and does not limit the testing
to areas rearward of the LERL, if WAD1000 is forward of that line.
Thus, test points may be on the bumper or grille area. For the FMVSS
No. 228 procedure, there are no test points forward of the LERL,
regardless of the WAD1000 location. Again, in section VI.C of this
preamble we have requested comment on testing to WAD1000 regardless of
its location and the most forward of WAD1000 or the 82.5 mm Offset
line. Similarly, for the NCAP RFC there is no Offset Line of any size
on the rear boundary. Additionally, the windshield is a valid impact
location. In section VI.C of this preamble, we requested comment on
extending the testing to WAD2100 and onto the windshield.
The NCAP RFC also differs from FMVSS No. 228 on how impact points
are targeted. As explained, in section VII.C of this preamble, we
explain how FMVSS No. 228 uses a first point of contact/3D method to
target any point within the Child and Adult Headform Test Area that can
be touched by the impactor. Thus, there are an infinite number of test
locations. However, such a testing system does not lend itself to a
scoring scheme. The NCAP RFC limits the number of valid test points by
marking off a 100 mm by 100 mm grid within the test border. These grid
points are targeted via the ``Aiming Point,'' which is the intersection
of the line of flight of the headform centerline with the hood surface.
Due to the angle of the impact direction, the impact point on the hood
will always be slightly forward of the Aiming Point. Nonetheless, the
HIC score for the impact is assigned to the grid point that was aimed
at (HIC15 < 650 = Green, 650 <= HIC15 < 1000 = Yellow, 1000 <= HIC15 <
1350 = Orange, 1350 <= HIC15 < 1700 = Brown, HIC15 >= 1700 = Red). This
method has the benefit of being able to assign a HIC score to every
grid point regardless of the contour of the hood, which is essential
for a rating scheme. However, such a method is not necessary for FMVSS
No. 228, which incorporates a pass/fail requirement for any point that
can be contacted within the test area. In addition, the grid method is
limited in its ability to test a specific location on the hood that may
be particularly injurious to a pedestrian, which, again, is important
for a minimum performance requirement.
For the NCAP RFC, the impactor used (Child versus Adult Headform)
depends

[[Page 76976]]

on the WAD of the grid point. For grid points between WAD1000 and
WAD1500, the Child Headform Impactor is used. For grid points between
WAD1700 and WAD2100, the Adult Headform is used. The above is
consistent with the FMVSS No. 228 procedure. However, unlike FMVSS No.
228, the NCAP RFC procedure has a provision where both the Child and
Adult Headforms are used at grid locations between WAD1500 and WAD1700
if the RRL is within these WAD ranges. We noted this difference in
section VI.C of this preamble, and request comment on modifying the
final rule test procedure accordingly. As we stated earlier, we do not
think that actual hoods will have an abrupt transition engineered into
their design, and the FMVSS No. 228 procedure reduces the need to
conduct unnecessary headform tests. Further, as the limited nature of
the NCAP RFC grid points is more restrictive of testing than the
proposed FMVSS No. 228 procedure, the grid approach lends itself more
readily to the testing with both impactors in the transition zone.
Finally, the impact speed for the NCAP RFC is 40 km/h as opposed to
35 km/h in FMVSS No. 228. NHTSA sees no inherent conflict in this
difference. We continue to believe the 35 km/h impact is well supported
by field data as providing a regulatory minimum performance standard
for pedestrian head impact. Using a higher impact speed in the NCAP RFC
may mean that not all vehicles receive credit for NCAP pedestrian
protection, thus giving consumers additional information with which to
make their vehicle purchasing decision and incentivizing designs that
go beyond the minimum provided to meet the FMVSS.
As the above discussion shows, there are important differences
between the NCAP RFC and FMVSS No. 228. The fact that there will be a
pedestrian crashworthiness component of NCAP does not mean there should
not be a standard related to the same safety risk. For example, the
introduction of the frontal and side crashworthiness portions of NCAP
did not lead the agency to abandon standards in these areas. NCAP
remains a consumer information program that provides important
information for vehicle purchasing decisions, which encourages
manufacturers to voluntarily make changes to vehicles to attain
positive NCAP test results and thereby improve safety. FMVSSs, on the
other hand, are mandatory and specify a minimum level of safety that
all vehicles sold must provide. The two programs are complementary and
beneficial to safety.

XII. Proposed Lead Time

We propose that FMVSS No. 228 would become effective the first
September 1, two years after the date of publication of a final rule.
For example, if a final rule were published in October of 2025, the
effective date would be September 1, 2028. Most passenger cars,
minivans, cross-over vehicles, and other vehicles under 3500 kg (7716
lb) GVWR sold in the U.S. share similar global designs as models
currently sold in the E.U. Manufacturers probably would need
considerably less time than two years to meet the requirements
specified in the proposed rule due to their familiarity with similar
requirements already established in the EU. However, we propose to
allow manufacturers two years of lead time to assure that vehicles
unique to the U.S. market--such as large SUVs and pickup trucks--are in
full compliance with the standard.\165\ In addition, two years may be
needed even for the vehicles that have European variants.
---------------------------------------------------------------------------

\165\ Multistage manufacturers and alterers would be allowed an
additional year of lead time, in accordance with 49 CFR 571.8(b).
---------------------------------------------------------------------------

This NPRM initiates the process of implementing GTR 9 into the
FMVSS.\166\ Throughout this NPRM, however, particularly in sections
VI.C and XI, we have discussed our views on possibly adjusting the
GTR's test protocols and some performance requirements to maximize
safety benefits, address safety problems in the U.S., and develop a
standard meeting Safety Act criteria. Comments are requested on
whether, and the extent to which, such adjustments to implement or
expand the requirements of the proposal would affect the lead time
needed for manufacturers to implement the changes to their current
vehicle designs that meet GTR 9.
---------------------------------------------------------------------------

\166\ This NPRM uses different terminology than the GTR, but the
specifications for determining test borders and performance levels
is consistent with GTR 9.
---------------------------------------------------------------------------

From our observations of vehicle designs following the GTR in 2008,
it seems that vehicle front-ends, including hoods, have evolved in
design to meet European pedestrian protection requirements. The very
latest vehicle models--those that have been designed with the GTR in
mind from the platform level up--have contoured hoods, fenders, and
headlamps that dovetail closely with the borders and margins of the
GTR. An example of this is seen in one of the vehicles we tested: the
2011 Hyundai Tucson. The Tucson has curved headlamps that blend into
the fenders, and they are positioned just outside the Child Headform
Test Area and right up to the HIC Unlimited Margin. Without the margin,
about half of the headlamp would lie within the test area.
The GTR specifies that the rear border of the Child Headform Test
Area is either the WAD1700 line or a line 82.5 mm forward of the Rear
Reference Line, whichever is most forward. For the Tucson and the 2011
Buick Lacrosse, the two lines coincide (except for a very small area
near the hinges). Thus, there is no Adult Headform Test Area for either
of these vehicles. The design is such that the hood is exactly the size
necessary to avoid having an Adult Headform Test Area. We believe this
is unlikely to be a random occurrence. It appears that, for many years,
vehicle manufacturers have considered the GTR provisions when designing
their vehicles.
Notwithstanding how the current GTR border specifications seem to
affect hood designs, the agency's test data, summarized in section
VII.D, indicate that meeting the requirements discussed in this
preamble are practicable and that testing beyond the GTR borders into
the HIC Unlimited Area is also feasible. We request comments on the
lead time needed to achieve these outcomes.

XIII. Benefits and Costs

NHTSA has prepared a Preliminary Regulatory Impact Analysis (PRIA)
that assesses the benefits, costs and other impacts of this NPRM.\167\
Table XIII.1 provides a summary of the estimated annual incremental
benefits in terms of injuries and fatalities mitigated by the proposed
standard. The proposal is estimated to mitigate 67.4 fatalities. We
note that overall injuries, and all injury levels except MAIS 3, are
estimated to increase (represented by negative numbers in this table)
because fatalities averted become higher level injuries and higher
level injures averted become lower-level injuries. Although the net
total of non-fatal injuries from MAIS 1 to MAIS 5 increase under the
proposed rule due to change in those fatalities and non-fatal injuries,
overall there is a benefit at each MAIS level.
---------------------------------------------------------------------------

\167\ The PRIA is available in the docket for this NPRM and may
be obtained by downloading it or by contacting Docket Management at
the address or telephone number provided in the ADDRESSES section of
this document.

[[Page 76977]]

Table XIII.1--Summary of Annual Incremental Benefits
----------------------------------------------------------------------------------------------------------------
Benefits by vehicle type
Injury severity -------------------------------------- Total benefits
Passenger cars LTVs
----------------------------------------------------------------------------------------------------------------
MAIS 1................................................. -23.3 -47.2 -70.5
MAIS 2................................................. -3.7 1.2 -2.5
MAIS 3................................................. 7.0 16.8 23.9
MAIS 4................................................. -0.7 -0.3 -1.1
MAIS 5................................................. -2.5 -2.6 -5.1
Fatalities............................................. 27.8 39.7 67.4
----------------------------------------------------------------------------------------------------------------
Note: Values may not sum due to rounding. Negative values represent an increase in the number of injuries at
that specific severity.

Table XIII.2 provides the estimated annual cost of the proposal,
broken down by passenger car and LTV. Many manufacturers of vehicles
that would be subject to the proposed rule also manufacture vehicles in
the European Union (EU) market. Potentially, some of these vehicles
under production could be designed to a regulatory body's application
of GTR 9 that may differ from a NHTSA rule implementing GTR 9 in the
United States (see previous discussion of Amendment 3 in section
VIII.B). Therefore, for such vehicles, there could be a potential one-
time cost associated with redesigning vehicle hoods to comply with the
requirements adopted by NHTSA. The PRIA made use of a teardown study
conducted by the agency to compare the same or similar models of
vehicles with and without the countermeasures that would be used to
meet the proposed rule. The assemblies had no perceived differences in
design or assembly, but did indicate a slight difference in weight.
Therefore, the potential one-time cost associated with redesigning
vehicle hoods to meet the requirements specified in the proposed rule
are expected to be negligible, especially when considered on a per-
vehicle basis, across design cycles, and given the lead time specified
in the proposed rule. This analysis estimates the impact that the
incremental weight associated with meeting the requirements specified
in the proposed rule may have on fuel economy for passenger cars and
LTVs, respectively.
As the costs associated with fuel economy are incurred over the
course of a vehicle's lifespan, these costs are discounted. When
discounted at 3% and 7%, the incremental cost associated with the
impact to fuel economy is estimated to be in the range of $2.86-$3.50
for passenger cars. Similarly, LTVs have a per vehicle cost of $3.29-
$4.08. The overall combined fleet cost range is estimated to be from
$48.9 million to $60.4 million.

Table XIII.2--Total Annual Cost
----------------------------------------------------------------------------------------------------------------
Per vehicle cost Total fuel economy cost
Number of ---------------------------------------------------------------
Category vehicles Discounted at Discounted at Discounted at Discounted at
impacted 3% 7% 3% 7%
----------------------------------------------------------------------------------------------------------------
Passenger Car................... 6,257,000 $3.50 $2.86 $21,923,153 $17,887,026
LTV............................. 9,445,000 4.08 3.29 38,507,293 31,055,176
-------------------------------------------------------------------------------
Total Annual Cost........... .............. .............. .............. 60,430,447 48,942,202
----------------------------------------------------------------------------------------------------------------
Note: Values may not sum due to rounding.

Table XIII.3 provides a summary of the cost and benefits. To make a
comparison across alternatives, the primary outcome of the regulatory
action must be quantified on a single numerical index. Therefore,
safety benefits, measured in fatalities and non-fatal injuries
mitigated, are translated to Equivalent Lives Saved (ELS) and monetized
benefits. This table provides the cost, ELS, cost per ELS, monetized
benefits (assuming benefits of $11.9 million per ELS) and net benefits
at the 3% and 7% discount rates. The overall ELS ranges from 44.46 to
54.87. The cost per ELS is $1.10 million. The overall monetized
benefits range is $529.74 million-$653.76 million. After subtracting
the cost at each discount rate, the overall net benefits range is
$480.79 million-$593.3 million.

Table XIII.3--Summary of Costs and Benefits
[Millions]
----------------------------------------------------------------------------------------------------------------
Cost per
Discount rate Cost Equivalent equivalent Monetized Net benefits
lives saved live saved benefits
----------------------------------------------------------------------------------------------------------------
3%.............................. $60.43 54.87 $1.10 $653.76 $593.33
7%.............................. 48.94 44.46 1.10 529.74 480.79
----------------------------------------------------------------------------------------------------------------

XIV. Considered Alternatives

In several parts of this preamble, NHTSA explained how the agency
is considering alternatives to the GTR-based test procedure reflected
in this NPRM's regulatory text. The agency requested comments on the
alternatives that NHTSA would consider when developing the final rule.
In section VI.C, several options for expanding the
testable area were presented along with associated rationale. This also
included

[[Page 76978]]

consideration of including the windshield as an additional testing
area.
In section VIII.B, GTR 9 Amendment 3 is discussed.
Amendment 3 would, among other things, reduce the amount of HIC1000
test area compared to proposed FMVSS No. 228. In that section of the
preamble, we provide the costs and benefits of a regulatory approach
under Amendment 3. The details of this assessment can be found in the
PRIA for this NPRM as Alternative 1.
We now discuss a potential modification to the test
procedure that would require the entire Hood Top to be tested. Under
this version of the test procedure, the HIC Unlimited Area would no
longer exist. Any point within the boundary of the Hood Top, as
described in section VI.A, would be a valid impact point. The agency
sees this as consistent with the notion that the HIC Unlimited areas
were added due to practicability concerns, not based on the concept
that a pedestrian's head would not strike these parts of the Hood Top.
Therefore, a procedure including these areas would provide an outcome
more aligned with optimizing the safety benefits of this rulemaking.
The PRIA discusses this approach as Alternative 3.
We believe reduction of the area of the hood that can be tested by
subtracting areas at the perimeter of the Hood Top was based on the
premise that it was simply not practicable to design hoods with
perimeters that could meet HIC1000 or HIC1700 limits. The agency test
data summarized in section VII.D, however, indicates that it is
feasible for U.S. vehicles to achieve the HIC requirements in the ``HIC
Unlimited Area.'' Further, in order to achieve a significant safety
benefit to pedestrians, the areas designated as the HIC Unlimited Area
using the procedure in GTR 9 could, instead, be required to meet either
a HIC 1000 or 1700 limit, depending on the manufacturer's assignment of
those respective areas on the vehicle.
Under a procedure where the entire Hood Top is tested, the HIC1000
Area could be required to cover at least two-thirds of the Hood Top and
the HIC1700 Area could be required to cover the remainder.
Additionally, it is our expectation, due to previous agency testing,
that the 3D Method of impact point targeting would remain appropriate
even at the edges of the Hood Top.
Under a test scheme that includes the entire Hood Top as the
testable area, an issue discussed earlier in this preamble would remain
for large vehicles whose LERL is rearward of WAD1000. For such
vehicles, if the test area were limited only to the Hood Top, areas on
the front of the vehicle that could be contacted by a child's head
would not be regulated. We note that this is also the case with the
current proposed standard, as mentioned above in section VI.C.1.a.
Comments are requested on the merits of including a procedure for
testing the grille area on such vehicles, assuming FMVSS No. 228 were
to include the entire Hood Top as the testable area.
Table XIV.1 shows a comparison of the estimated benefits in terms
of ELS and monetized benefits for an FMVSS No. 228 that reflects the
wording of GTR 9 (presented in the NPRM's regulatory text) and a
requirement that would test the entire Hood Top. Additional details on
the benefits and cost of the proposal are presented in section XIII.
Under a requirement to test the entire Hood Top, both ELS and monetized
benefits would be approximately 159% of that under the proposed rule
(i.e., the NPRM's regulatory text).
NHTSA performed a break-even analysis for this alternative. This
break-even analysis considers the cost at which this regulatory
alternative would be net cost-effective and net beneficial. NHTSA
estimated that break-even is at $50.48-$62.28 per vehicle cost,
discounted at 7% and 3%. NHTSA requests information on the potential
costs of this alternative.
Although this alternative is estimated to be substantially more
beneficial than the rule presented in the NPRM's regulatory text, in
addition to a lack of information about cost, the agency believes there
are unknowns related to the practicability of testing the entire Hood
Top. The agency requests comment on the alternative of requiring
testing of the entire Hood Top.

Table XIV.1--Equivalent Lives Saved and Monetized Benefits
[Millions]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cost Equivalent lives Cost per Monetized benefits Net benefits
-------------------- saved equivalent life ---------------------------------------
Regulatory option -------------------- saved
3% 7% -------------------- 3% 7% 3% 7%
3% 7% 3% 7%
--------------------------------------------------------------------------------------------------------------------------------------------------------
#1: Requirements are the same as the E.U. $60.43 $48.94 32.28 26.20 $1.87 $1.87 $384.51 $312.09 $324.08 $263.15
interpretation of GTR 9 regarding test area (GTR 9
Amendment 3).......................................
#2: Proposed Rule (as presented in the NPRM's 60.43 48.94 54.87 44.46 1.10 1.10 653.76 529.74 593.33 480.79
regulatory text)...................................
#3: Requirements apply to the entire Hood Top (No ........ ........ 87.13 70.61 ........ ........ 1,038.3 841.51 ........ ........
HIC Unlimited Area)................................
--------------------------------------------------------------------------------------------------------------------------------------------------------

XV. Rulemaking Analyses and Notices

Executive Order (E.O.) 12866 (Regulatory Planning and Review), E.O.
13563, E.O. 14094, and DOT Rulemaking Procedures

NHTSA has considered the impact of this rulemaking action under
E.O. 12866, E.O. 13563, E.O. 14094, and the Department of
Transportation's regulatory procedures. This rulemaking is
``significant'' under E.O. 12866, ``Regulatory Planning and Review,''
and has been reviewed by the Office of Management and Budget. This NPRM
proposes to implement the provisions of GTR 9 into NHTSA's regulations
as a Federal Motor Vehicle Safety Standard, with possible adjustments
to address safety issues and a regulatory framework that are unique to
the U.S. The costs, benefits, and other economic impacts of this NPRM
have been discussed in sections above and are analyzed in detail in the
PRIA.

Rulemaking Summary, 5 U.S.C. 553(b)(4)

As required by 5 U.S.C. 553(b)(4), a summary of this rule can be
found in the Abstract section of the Department's Unified Agenda entry
for this rulemaking at https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202304&RIN=2127-AK98.

Regulatory Flexibility Act

Pursuant to the Regulatory Flexibility Act (5 U.S.C. 601 et seq.,
as amended by the Small Business Regulatory Enforcement Fairness Act
(SBREFA) of 1996) whenever an agency is required to publish a notice of
proposed rulemaking or final rule, it must prepare and make available
for public comment a

[[Page 76979]]

regulatory flexibility analysis that describes the effect of the rule
on small entities (i.e., small businesses, small organizations, and
small governmental jurisdictions), unless the head of an agency
certifies the rule will not have a significant economic impact on a
substantial number of small entities. Agencies must also provide a
statement of the factual basis for this certification. (5 U.S.C.
605(b))
I certify that this proposed rule would not have a significant
economic impact on a substantial number of small entities. Although
NHTSA is not required to issue an initial RFA, NHTSA sets forth the
initial RFA below to provide the factual basis for the certification,
and as a means of seeking comment on the certification and the economic
impact of the proposed rule.
An initial RFA must contain (5 U.S.C. 603):
1. A description of the reasons why action by the agency is being
considered;
2. A succinct statement of the objectives of, and legal basis for a
proposed or final rule;
3. A description of and, where feasible, an estimate of the number
of small entities to which the proposed or final rule will apply;
4. A description of the projected reporting, record keeping and
other compliance requirements of a proposed or final rule including an
estimate of the classes of small entities which will be subject to the
requirement and the type of professional skills necessary for
preparation of the report or record;
5. An identification, to the extent practicable, of all relevant
Federal rules which may duplicate, overlap, or conflict with the
proposed or final rule;
6. A description of any significant alternatives to the proposed or
final rule which accomplish the stated objectives of applicable status
and which minimize any significant economic impact of the rule on small
entities.
An RFA is not required if the head of the agency certifies that the
proposed rule will not have a significant impact on a substantial
number of small entities. The head of NHTSA has made such a
certification. The factual basis for the certification (5 U.S.C.
605(b)) is set forth below. Although NHTSA is not required to issue an
initial RFA, we discuss below many of the issues that an initial RFA
would address.
1. A Description of the Reasons Why Action by the Agency Is Being
Considered
NHTSA is considering this action to improve the safety of
pedestrians. In particular, this action aims to address the injury
severity in regard to head injuries incurred to pedestrians as the
result of being struck by a light vehicle. By setting the HIC
requirement, this action ensures that passenger vehicles are designed
to mitigate the risk of serious to fatal child and adult head injury in
pedestrian crashes. NHTSA is also initiating this rulemaking as part of
the agency's obligations under the 1998 Agreement. See section IV of
this preamble.
2. A Succinct Statement of the Objectives of, and Legal Basis for the
Rulemaking
NHTSA is proposing these changes under the authority of 49 U.S.C.
322, 30111, 30115, 30117, and 30666, as well as a delegation of
authority at 49 CFR 1.95. The agency is authorized to issue Federal
motor vehicle safety standards that meet the need for motor vehicle
safety.
3. A Description of and, Where Feasible, an Estimate of the Number of
Small Entities to Which the Final Rule Will Apply
The proposed rule would affect motor vehicle manufacturers and
second-stage or final stage manufacturers. We conducted an analysis to
identify if there are any such firms that exist that are small
businesses. Business entities are defined as small businesses using the
North American Industry Classification System (NAICS) code. One of the
criteria for determining size, as stated in 13 CFR 121.201, is the
number of employees in the firm. For establishments primarily engaged
in manufacturing or assembling automobiles, light- and heavy-duty
trucks, buses, motor homes, and new tires the firm must have fewer than
1,500 employees to be classified as a small business, and motor vehicle
body manufacturing which must have fewer than 1,000 employees.\168\ For
alterers and final-stage manufacturers, the firm must have fewer than
500 employees to be classified as a small business.\169\
---------------------------------------------------------------------------

\168\ See NAICS codes 336110 (Automobile and Light Duty Motor
Vehicle Manufacturing), 336120 (Heavy Duty Truck Manufacturing), and
336211 (Motor Vehicle Body Manufacturing) https://www.sba.gov/sites/sbagov/files/2023-06/Table%20of%20Size%20Standards_Effective%20March%2017%2C%202023%20%282%29.pdf.
\169\ See NAICS code 336211 (Motor Vehicle Body Manufacturing)
https://www.sba.gov/sites/sbagov/files/2023-06/Table%20of%20Size%20Standards_Effective%20March%2017%2C%202023%20%282%29.pdf.
---------------------------------------------------------------------------

Currently, there are at least 12 small light vehicle manufacturers
in the United States. \170\ Table XV.1 provides information about the
12 small volume domestic manufacturers in MY 2020. All are small
manufacturers, having fewer than 1,500 employees.
---------------------------------------------------------------------------

\170\ Classified in NAICS under Subsector 336--Transportation
Equipment Manufacturing for Automobile and Light Duty Motor Vehicle
Manufacturing (336110) and Heavy Duty Truck Manufacturing (336120).
Available at: https://www.sba.gov/document/support--table-size-standards.
\171\ Provided to illustrate the current population of small
vehicle manufacturers.

Table XV.1--Small Volume Vehicle Manufacturers
[MY 2020] \171\
----------------------------------------------------------------------------------------------------------------
Number of
Manufacturer Type of vehicles employees MSRP for vehicles (appx.)
(appx.)
----------------------------------------------------------------------------------------------------------------
Anteros Coachworks...................... Specialty Sports Cars..... 2 $110,000.
Callaway Cars........................... Specialty Sports Cars..... 50 ~$17,000 above base (GM)
vehicle price.
Carroll Shelby International............ Specialty Sports Cars..... 170 $86,085-$180,995+.
Equus Automotive........................ Specialty Sports Cars..... 25 $250,000+.
Falcon Motorsports...................... Specialty Sports Cars..... 2 $300,000-$400,000.
Faraday Future.......................... Electric.................. 350 $225,000.
Fisker Inc.............................. Electric.................. <200 $37,499+.
Karma Automotive........................ Electric.................. 750 $135,000.
Panoz................................... Specialty Sports Cars..... <50 $159,900+.
Rossion Automotive...................... Specialty Sports Cars..... 70 $80,000.
Saleen Automotive....................... Specialty Sports Cars..... 170 $48,000-$100,000+.

[[Page 76980]]

SSC North America....................... Specialty Sports Cars..... 9 $2,000,000.
----------------------------------------------------------------------------------------------------------------

4. A Description of the Projected Reporting, Recordkeeping and Other
Compliance Requirements of the Proposed Rule, Including an Estimate of
the Classes of Small Entities Which Will Be Subject to the Requirement
and the Type of Professional Skills Necessary for Preparation of the
Report or Record
The proposed rule does not create any new reporting or
recordkeeping requirements, nor does it affect any existing reporting
or recordkeeping requirements.
Manufacturers would have to self-certify the compliance of their
vehicles with the new FMVSS No. 228. Manufacturers currently self-
certify the compliance of their vehicles to a host of Federal motor
vehicle safety standards, many of which are much more complex than the
standard proposed by this NPRM. The burden and cost of certifying to
proposed FMVSS No. 228 is relatively small. The performance test is
done with an impactor without crash testing the vehicles, and multiple
impacts can be performed on a single hood to assess conformance. The
vehicle manufacturer is not required by the FMVSS to test every point
on the hood; instead, it only must ensure that the hood will meet FMVSS
No. 228 when tested by NHTSA in an agency compliance test. Thus, the
small manufacturer, knowing its vehicle, can identify the part of the
hood least likely to meet the standard and can focus its testing there.
If that part of the hood can be made to meet the standard, the small
manufacturer can determine through engineering analyses and other means
that other parts of the hood can meet the standard as well. This is to
say, a small entity is not directed by the standard to test in any way.
Small entities can easily base their certification on simple headform
testing, straightforward engineering analyses, modeling, a combination
of these, or other such means to certify to the proposed standard.
Although a small entity is not required by NHTSA to test to self-
certify compliance with proposed FMVSS No. 228, if they wish to perform
the physical tests described in the proposed standard, they could
readily contract with an outside testing laboratory to conduct the
headform impact tests in the proposal. (NHTSA itself has contracted
with labs for such testing in the past.) The number of tests to be
performed on a particular hood to certify compliance would be at the
discretion of the manufacturer. Because of the manufacturer's in-depth
knowledge of its vehicle design, the symmetry of hood design and
predictability of results, and the depth of engineering judgment and
knowledge in this area, however, NHTSA believes it is reasonable that
the number of necessary test points could be reduced to the locations
with the least compliance margin. To illustrate, NHTSA in the past has
assessed hood performance based on a test series of 10 impacts, at a
total cost of approximately $8,000 for the 10 impacts. Because these
impacts may involve more than a single hood, we would include an
additional cost for hood parts, which results in an overall estimated
testing cost of $10,000 for certification testing. This overall cost
can then be amortized over the entire number of vehicles produced
matching the test design. Thus, the amortized cost would not constitute
a significant percentage of the relative cost of the vehicle. Comments
are requested on these estimates.
As with large manufacturers, small manufacturers would self-certify
compliance to FMVSS No. 228 by the same certification label now
required for all applicable Federal motor vehicle safety standards. The
label is placed on the vehicle, usually in the door jamb on light
vehicles. Adding FMVSS No. 228 certification to the label is expected
to result in minimal impact on small entities.
NHTSA does not believe the small manufacturers listed in table XV.1
of this analysis are developing hood systems and/or related hardware
for installation on the vehicles they manufacture. In today's motor
vehicle market, small vehicle manufacturers, who are less able than
large manufacturers to take advantage of economies of scale to lower
production costs, typically produce specialized, expensive vehicles and
could obtain the hoods from a supplier (a large entity). Regardless of
whether small manufacturers turn to a supplier, the vehicle
manufacturer would be able to certify its vehicles to FMVSS No. 228
through the use of energy-absorbing structures and strategic layout of
hard engine components vis-a-vis the hood surface; designing and
manufacturing a compliant hood is relatively uncomplicated.
Furthermore, there are a significant number of final-stage
manufacturers and alterers (several hundred) that could be impacted by
the proposed rule. These manufacturers buy incomplete vehicles from the
first-stage vehicle manufacturers or complete vehicles that they alter
before first sale, respectively. Many of these vehicles are van
conversions, but there are a variety of vehicles affected. These final-
stage manufacturers would likely meet the standard by passing on the
costs of compliance by the first-stage vehicle manufacturer to the
consumer. Alterers would likely refrain from modifying the hood, which
allows them to pass on the compliance costs by the original
manufacturer of the vehicle to the consumer. Thus, while there are a
substantial number of final stage manufacturers and alterers
potentially impacted by the proposed rule, we do not believe the
proposed rule will have a significant economic impact on the entities.
Either a pass-through certification process will apply to these
manufacturers, or they will do the work themselves to certify the
vehicle.
NHTSA does not believe that the potential costs of any necessary
hood design would have significant impacts on a substantial number of
small entities. In considering potential costs associated with
redesigning hoods, we first note that this potential one-time cost
would be spread out on a per-vehicle basis, with costs shared across
model years of a given generation. Furthermore, as the majority of the
small entities identified also sell vehicles in the EU,\172\ much of
the burden and associated cost of redesigning hoods would already be

[[Page 76981]]

incurred to meet the standards already in place in the EU.
---------------------------------------------------------------------------

\172\ At least seven of the 12 small entities identified also
sold vehicles in the EU. For those who may not sell vehicles in the
EU, the average vehicle sales prices was approximately $587,000 and
would likely require a special order for purchase.
---------------------------------------------------------------------------

NHTSA considers in this paragraph how such costs may impact these
small entities. It is assumed that any incremental costs incurred to
meet the requirements specified in the proposed rule would be passed on
to consumers and, therefore, potentially impact demand. The vehicles
produced by manufacturers listed in the table can roughly be grouped
into three classes: (1) luxury/ultra-luxury vehicles; (2) alternative
electric vehicles; and (3) modified vehicles from other manufacturers.
Luxury/ultra-luxury vehicles are considered to be Veblen goods. Veblen
goods are those in which demand increases as price increases.
Therefore, any potential incremental costs would not have negative
impacts on the demand for these particular vehicles. Additionally, as
all three categories of the vehicles manufactured by these small
entities are specialty vehicles, demand for these vehicles would be
inelastic due to a lack of substitutes. That is, it is expected that
consumers who seek out these specific vehicles would not be impacted by
potential price changes as a result of manufacturers passing costs on
to consumers.
5. An Identification, to the Extent Practicable, of All Relevant
Federal Rules Which May Duplicate, Overlap, or Conflict With The
Proposed Rule
We know of no Federal rules which duplicate, overlap, or conflict
with this proposed rule.
6. Each RFA Shall Also Contain a Description of Any Significant
Alternatives to the Proposed Rule Which Accomplish the Stated
Objectives of Applicable Statutes and Which Minimize any Significant
Economic Impact of the Proposal on Small Entities
In addition to the requirements included in this NPRM, NHTSA
considered a less stringent regulatory alternative in which the
requirements specified in the proposed rule would match the E.U.
interpretation of GTR 9 and a more stringent alternative in which the
requirements specified in the proposed rule would be applicable to the
entire Hood Top, i.e., the Test Area would encompass the entire Hood
Top. When comparing the less stringent regulatory alternative to the
proposed rule, NHTSA determined that the costs would be very similar,
and due to data limitations, assumed the costs to be the same. The
proposed rule, however, provides more benefits relative to the less
stringent regulatory alternative. While the more stringent regulatory
alternative would offer greater overall benefits, we were unable to
estimate the cost for the more stringent regulatory alternative due to
data limitations. Overall, the less stringent regulatory alternative
and proposed rule are only associated with fuel economy costs incurred
over the life span of the vehicles impacted. Due to uncertainty about
the feasibility and costs associated with the more stringent regulatory
alternative, NHTSA was not able to assess the potential impacts of that
regulatory alternative on small entities. While costs could increase
with the more stringent regulatory alternative, it is not NHTSA's
preferred alternative. If the agency decides the alternative should be
further pursued, the agency will consider the impacts to small entities
when determining whether to finalize the more stringent regulatory
alternative.
We have identified no meaningful alternatives that both: (1) do not
rely on the establishment of a HIC requirement; and (2) are expected to
achieve improvements in pedestrian safety consistent with those
expected under the proposed rule. However, in recognition of
manufacturing differences between large manufacturers and these
specific types of small manufacturers, NHTSA is proposing to provide
final-stage manufacturers and alterers an additional year of lead time
for manufacturer certifications of compliance.\173\ NHTSA anticipates
that hood components and designs meeting FMVSS No. 228 may be developed
by vehicle designers and suppliers and integrated into the fleets of
larger vehicle manufacturers first, before these small manufacturers.
This NPRM recognizes this and proposes to provide final-stage
manufacturers and alterers more lead time. As designers and suppliers
may prioritize meeting the demands of larger manufacturers, this
additional lead time will allow small manufacturers to work with
designers and suppliers without any stoppage in production Although, as
discussed above, we do not project the proposed rule to have a
significant economic impact on a substantial number of small entities,
the additional lead time would provide flexibility to further minimize
any impacts. The NPRM does not provide additional lead time for other
small manufacturers such as listed in table XV.1 who manufacture
complete vehicles because the latter have the engineering resources to
certify compliance in the same time frame as large manufacturers. Such
small manufacturers perform or control much of the design and
development of the vehicles they produce unlike typical final-stage
manufacturers and alterers. With their engineering resources and
control over the manufacturing processes, those small manufacturers
have the ability to consider the proposed FMVSS No. 228 requirements
and modify the hood as needed, like other manufacturers.
---------------------------------------------------------------------------

\173\ This approach accords with 49 CFR 571.8(b).
---------------------------------------------------------------------------

National Environmental Policy Act

NHTSA has analyzed this rulemaking for the purposes of the National
Environmental Policy Act and determined that it will not have any
significant impact on the quality of the human environment.

Executive Order 13132 (Federalism)

NHTSA has examined this proposed 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 rulemaking will not have sufficient federalism implications to
warrant consultation with State and local officials or the preparation
of a federalism summary impact statement. The proposed rule will 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.''
NHTSA rules can preempt in two ways. First, the National Traffic
and Motor Vehicle Safety Act contains an express preemption 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 by Congress that preempts any
non-identical State legislative and administrative law addressing the
same aspect of performance.
The express preemption provision described above is subject to a
savings clause under which ``[c]ompliance with a motor vehicle safety
standard prescribed under this chapter does not exempt a person from
liability at common law.'' 49 U.S.C. 30103(e). Pursuant to this
provision, State common law tort causes of action against motor vehicle
manufacturers

[[Page 76982]]

that might otherwise be preempted by the express preemption provision
are generally preserved.
However, the Supreme Court has recognized the possibility, in some
instances, of implied preemption of such State common law tort causes
of action by virtue of NHTSA's rules, even if not expressly preempted.
This second way that NHTSA rules can preempt is dependent upon there
being an actual conflict between an FMVSS and the higher standard that
would effectively be imposed on motor vehicle manufacturers if someone
obtained a State common law tort judgment against the manufacturer,
notwithstanding the manufacturer's compliance with the NHTSA standard.
Because most NHTSA standards established by an FMVSS are minimum
standards, a State common law tort cause of action that seeks to impose
a higher standard on motor vehicle manufacturers will generally not be
preempted. However, if and when such a conflict does exist--for
example, when the standard at issue is both a minimum and a maximum
standard--the State common law tort cause of action is impliedly
preempted. See Geier v. American Honda Motor Co., 529 U.S. 861 (2000).
Pursuant to Executive Orders 13132 and 12988, NHTSA has considered
whether this rulemaking could or should preempt State common law causes
of action. The agency's ability to announce its conclusion regarding
the preemptive effect of one of its rules reduces the likelihood that
preemption will be an issue in any subsequent tort litigation. To this
end, the agency has examined the nature (e.g., the language and
structure of the regulatory text) and objectives of this proposed rule
and finds that it, like many NHTSA rules, would prescribe only a
minimum safety standard. As such, NHTSA does not intend this rulemaking
to preempt state tort law that would effectively impose a higher
standard on motor vehicle manufacturers than that established by the
rule. Establishment of a higher standard by means of State tort law
will not conflict with the minimum standard adopted here. Without any
conflict, there could not be any implied preemption of a State common
law tort cause of action.

Civil Justice Reform

Section 3(b) of Executive Order 12988, ``Civil Justice Reform'' (61
FR 4729, February 7, 1996) requires that, when promulgating a new
regulation, Executive agencies make every reasonable effort to ensure
that the regulation: (1) Clearly specifies any preemptive effect; (2)
clearly specifies any 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, either
explicitly or by reference to other regulations or statutes that
explicitly define those items; and (6) addresses other important issues
affecting clarity and general draftsmanship of regulations 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 proposed 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.

Paperwork Reduction Act (PRA)

Under the PRA of 1995, a person is not required to respond to a
collection of information by a Federal agency unless the collection
displays a valid OMB control number. The agency has analyzed the
proposed standard and determined that there are no reporting
requirements that require an OMB control number. The proposed
regulatory text would require that information must be made available
under the agency enforcement authority provided in 49 U.S.C. 30166.

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 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.
Voluntary consensus standards are technical standards developed or
adopted by voluntary consensus standards bodies. Technical standards
are defined by the NTTAA as ``performance-based or design-specific
technical specification and related management systems practices.''
They pertain to ``products and processes, such as size, strength, or
technical performance of a product, process or material.'' 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.
This proposal to adopt GTR 9 is consistent with the goals of the
NTTAA. This NPRM proposes to adopt a global consensus standard. The GTR
was developed by a global regulatory body and is designed to increase
global harmonization of differing vehicle standards. The GTR leverages
the expertise of governments in developing a vehicle standard to reduce
the risk of pedestrian head injury in impacts. NHTSA's consideration of
GTR 9 accords with the principles of NTTAA as NHTSA's consideration of
an established, proven regulation has reduced the need for NHTSA to
expend significant agency resources on the same safety need addressed
by GTR 9. This NPRM explains the reasons the FMVSS under consideration
differs in some respects from GTR 9, and why NHTSA is considering
additional changes to GTR 9 for the final rule. NHTSA will consider the
comments to the NPRM and other information in drafting a final rule. If
differences remain between the final rule and the GTR, the agency will
explain in the final rule NHTSA's reasons for deciding such differences
are warranted, consistent with the NTTAA.

Unfunded Mandates Reform Act

Section 202 of the Unfunded Mandates Reform Act of 1995 (UMRA),
Public Law 104-4, 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 (adjusted for
inflation with base year of 1995) in any one year. Adjusting this
amount by the implicit gross domestic product price deflator for the
year 2021 results in $178 million (2021 index value of 270.97/1995
index value of 152.40 = 1.78 \174\). This proposed rule would not
result in a cost of $178 million or more in any one year to either
State, local, or tribal governments, in the aggregate, or the private
sector. Thus, this proposed rule is not subject to the requirements of
sections 202 of the UMRA.
---------------------------------------------------------------------------

\174\ Consumer Price Index Data from 1913 to 2023
(usinflationcalculator.com)

---------------------------------------------------------------------------

[[Page 76983]]

Incorporation by Reference

Under regulations issued by the Office of the Federal Register (1
CFR 51.5(a)), an agency must summarize in the preamble of a proposed or
final rule the material it incorporates by reference and discuss the
ways the material is reasonably available to interested parties or how
the agency worked to make materials available to interested parties.
NHTSA proposes to incorporate by reference SAE Recommended Practice
J211-1, ``Instrumentation for Impact Test--Part 1--Electronic
Instrumentation,'' revised August 2022 (SAE J211/1). Previous versions
of this SAE standard are incorporated in 49 CFR 571.5(l)(2) through
(5). The SAE J211/1 standard provides guidelines and recommendations
for techniques of measurements used in impact tests to achieve
uniformity in instrumentation practice and in reporting results.
Signals from impact tests have to be filtered following the standard's
guidelines to eliminate noise from sensor signals. Following J211/1
guidelines provides a basis for meaningful comparisons of test results
from different sources. The SAE material is available for review at
NHTSA and is available from SAE International.

Severability

The issue of severability of FMVSSs is addressed in 49 CFR 571.9.
It provides that if any FMVSS or its application to any person or
circumstance is held invalid, the remainder of the part and the
application of that standard to other persons or circumstances is
unaffected. NHTSA seeks comment on the issue of severability.

Regulation Identifier Number

The DOT assigns a regulation identifier number (RIN) to each
regulatory action listed in the Unified Agenda of Federal Regulations.
The Regulatory Information Service Center publishes the Unified Agenda
in April and October of each year. You may use the RIN contained in the
heading at the beginning of this document to find this action in the
Unified Agenda.

Plain Language

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

XVI. Public Participation

How long do I have to submit comments?

Please see DATES section at the beginning of this document.

How do I prepare and submit comments?

Your comments must be submitted in writing.
To ensure that your comments are correctly filed in the
Docket, please include the Docket Number shown at the beginning of this
document in your comments.
Your comments must not be more than 15 pages long. (49 CFR
553.21). We established this limit to encourage you to write your
primary comments in a concise fashion. However, you may attach
necessary additional documents to your comments. There is no limit on
the length of the attachments.
If you are submitting comments electronically as a PDF
(Adobe) File, NHTSA asks that the documents be submitted using the
Optical Character Recognition (OCR) process, thus allowing NHTSA to
search and copy certain portions of your submissions. Comments may be
submitted to the docket electronically by logging onto the Docket
Management System website at http://www.regulations.gov. Follow the
online instructions for submitting comments.
Please note that pursuant to the Data Quality Act, in
order for substantive data to be relied upon and used by the agency, it
must meet the information quality standards set forth in the OMB and
DOT Data Quality Act guidelines. Accordingly, we encourage you to
consult the guidelines in preparing your comments. OMB's guidelines may
be accessed at https://www.govinfo.gov/content/pkg/FR-2002-02-22/pdf/R2-59.pdf. DOT's guidelines may be accessed at https://www.transportation.gov/dot-information-dissemination-quality-guidelines.
Tips for Preparing Your Comments
When submitting comments, please remember to:
Identify the rulemaking by docket number and other
identifying information (subject heading, Federal Register date, and
page number).
Explain why you agree or disagree, suggest alternatives,
and substitute language for your requested changes.
Describe any assumptions and provide any technical
information and/or data that you used.
If you estimate potential costs or burdens, explain how
you arrived at your estimate in sufficient detail to allow for it to be
reproduced.
Provide specific examples to illustrate your concerns and
suggest alternatives.
Explain your views as clearly as possible, avoiding the
use of profanity or personal threats.
Make sure to submit your comments by the comment period
deadline identified in the DATES section above.

How can I be sure that my comments were received?

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

How do I submit confidential business information?

If you wish to submit any information under a claim of
confidentiality, you should submit three copies of your complete
submission, including the information you claim to be confidential
business information, to the Chief Counsel, NHTSA, at the address given
above under FOR FURTHER INFORMATION CONTACT. In addition, you should
submit two copies, from which you have deleted the claimed confidential
business information, to Docket Management at the address given above
under ADDRESSES. When you send a comment containing information claimed
to be confidential business information, you should include a cover
letter setting forth the information specified in our confidential
business information regulation. (49 CFR part 512). To facilitate
social distancing during COVID-19, NHTSA is temporarily accepting
confidential business information electronically. Please see https://www.nhtsa.gov/coronavirus/submission-confidential-business-information
for details.

[[Page 76984]]

Will the Agency consider late comments?

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

How can I read the comments submitted by other people?

You may read the comments received by Docket Management at the
address given above under ADDRESSES. The hours of the Docket are
indicated above in the same location. You may also see the comments on
the internet. To read the comments on the internet, go to https://www.regulations.gov. Follow the online instructions for accessing the
dockets.
Please note that, even after the comment closing date, we will
continue to file relevant information in the Docket as it becomes
available. Further, some people may submit late comments. Accordingly,
we recommend that you periodically check the Docket for new material.

Potential Equity or Climate Change Impacts

The DOT recognizes that climate variability and change pose
potential threats to U.S. transportation systems. In addition, ensuring
equity and accessibility for every member of the traveling public is
one of the Department's highest priorities. NHTSA requests comment on
any potential climate change or equity impact of this proposed rule.

Privacy Act

In accordance with 5 U.S.C. 553(c), DOT solicits comments from the
public to better inform its decision-making process. DOT posts these
comments, without edit, including any personal information the
commenter provides, to www.regulations.gov, as described in the system
of records notice (DOT/ALL-14 FDMS), which can be reviewed at
www.transportation.gov/privacy and https://www.transportation.gov/individuals/privacy/privacy-act-system-records-notices. To facilitate
comment tracking and response, the agency encourages commenters to
provide their name, or the name of their organization; however,
submission of names is completely optional. Whether or not commenters
identify themselves, all timely comments will be fully considered.

List of Subjects in 49 CFR Part 571

Imports, Motor vehicle safety, Reporting and recordkeeping
requirements, Tires.

In consideration of the foregoing, NHTSA proposes to amend 49 CFR
part 571 as set forth below.

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

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

Authority: 49 U.S.C. 322, 30111, 30115, 30117 and 30166;
delegation of authority at 49 CFR 1.95.

0
2. Section 571.5 paragraph (l) is amended by redesignating paragraphs
(6) through (51) as paragraphs (7) through (52) and adding new
paragraph (6) to read as follows:

Sec. 571.5 Matter incorporated by reference.

* * * * *
(l) * * * * *
(6) SAE Recommended Practice J211-1 AUG2022, ``Instrumentation for
Impact Test--Part 1--Electronic Instrumentation,'' revised August 2022,
into Sec. 571.228.
* * * * *
0
3. Section 571.228 is added to read as follows:

Sec. 571.228 Standard No. 228; Pedestrian head protection.

S1. Scope. This standard establishes performance requirements for
vehicle hoods to protect pedestrians against head injury.
S2. Purpose. The purpose of this standard is to reduce the risk of
injury to pedestrians in the event of a collision.
S3. Application. This standard applies to passenger cars and to
multipurpose passenger vehicles, trucks, and buses with a GVWR of 4,536
kg or less, except for multipurpose passenger vehicles, trucks, and
buses where the distance, measured longitudinally on a horizontal
plane, between the transverse centerline of the front axle and the
seating reference point of the driver's seat is less than 1000 mm. This
standard also applies to any bidirectional vehicles within the subset
of vehicles described in this paragraph.
S4. Definitions. (All references below are to this Standard No.
228, 49 CFR 571.228, unless otherwise specified.)
Adult Headform Test Area means the area specified in S6.5.4.
Bidirectional vehicle means a vehicle that is intended to operate
at similar speeds and with similar maneuverability in both directions
of the vehicle longitudinal axis.
Child Headform Test Area means the area of the vehicle hood
specified in S6.5.3.
Combined Child and Adult Headform Test Area means the areas of the
Child Headform Test Area and Adult Headform Test Area together. If the
Adult Headform Test Area does not exist, the Child Headform Test Area
represents the Combined Child and Adult Headform Test Area.
Corner reference point of the Child Headform Test Area means the
intersection of the Child Headform Test Area (6.5.3) front border (HIC
Unlimited Margin of the Leading Edge Reference Line (S6.4.2) and the
side border (HIC Unlimited Margin of the Side Reference Line (S6.4.3).
Where multiple intersections occur, the most outboard intersection is
the corner reference point of the Child Headform Test Area and
constitutes the endpoint of the Child Headform Test Area front border
and side border.
Corner reference point of the Hood Area means the intersection of
the Hood Area (6.5.2) front border (Leading Edge Reference Line
(S6.3.2) or the WAD1000 line (S6.3.1)) and the side border (Side
Reference Line (S6.3.3)). Where multiple intersections occur, the most
outboard intersection defines the corner reference point of the Hood
Area and constitutes the endpoint of the Hood Area front border and the
side border.
Corner reference point of the Hood Top means the intersection of
the Hood Top (6.5.1) front border (Leading Edge Reference Line
(S6.3.2)) and the side border (Side Reference Line (S6.3.3)). Where
multiple intersections occur, the most outboard intersection defines
the corner reference point of the Hood Top and constitutes the endpoint
of the Hood Top front border and the side border.
Front means the leading portion of the vehicle during typical
operation, except for non-bidirectional vehicles that are operating in
a reverse gear intended for vehicles maneuvering in small areas.
Ground reference plane means a horizontal plane that passes through
the lowest points of contact for all tires of the vehicle.
Headform means a device specified in S8 and is the moving mass that
strikes the vehicle.
Head Injury Criterion (HIC) means an injury severity score that is
computed from accelerometer time histories using the following formula:

[[Page 76985]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.030

Where:

a is the resultant acceleration measured in units of gravity ``g''
(1 g = 9.81 m/s\2\);
t1 and t2 are the two time instants during the impact expressed in
seconds, defining an interval between the beginning and the end of
the recording period for which the value of HIC is a maximum (t2-t1
<= 15 ms)

HIC Unlimited Area means the area that shares an outer boundary
with the Hood Top and whose inner boundary is the HIC Unlimited Margin.
(See figure 7.)
HIC Unlimited Margin means the inner boundary of the HIC Unlimited
Area. It is the same as the outer boundary of the Combined Child and
Adult Headform Test Areas. (See figure 7.)
HIC1000 Area means the area within the Child Headform Test Area and
Adult Headform Test Area with a minimum area as specified in S5.2 and
where the HIC value must not exceed 1,000, as specified in S5.1(a).
HIC1700 Area means the area with borders as specified in S5.5 and
where the HIC value must not exceed 1,700, as specified in S5.1(b).
Hood Area means the area enclosed by the borders specified in
S6.5.2 that provides the basis for the amount of area in the Child
Headform Test Area and the Adult Headform Test Area, which must be
HIC1000 Area, as specified by S5.2.
Hood Top means the area enclosed by the borders specified in S6.5.1
and consisting of the HIC Unlimited Area, Child Headform Test Area and
Adult Headform Test Area.
Impact point(s) means the point(s) on the vehicle where the initial
contact with the headform occurs (point A in figure 1, provided for
illustration purposes). It is permissible to have multiple simultaneous
points of initial contact resulting from a headform launch. HIC value
requirements for multiple simultaneous points of initial contact are
specified in S5.3.
Non-contactable surfaces means areas within the Hood Top that
cannot be contacted by the headform due to the geometry of the hood,
such as a depression in the hood that the headform bridges across.
Wrap Around Distance (WAD) means a distance measured from the
ground reference plane to a point on the vehicle, by the use of a non-
stretch flexible tape or graduated wire, with one end held
perpendicular to the ground reference plane while the tape or wire is
maintained in the vehicle vertical longitudinal plane and wrapped
around the vehicle front end. As specified in S6.3.1, this procedure
results in identified WAD lines by using wires of different lengths,
e.g., a wire of 1,000 1 mm is used to identify a line at
1,000 mm from the ground reference plane. The naming conventions are to
follow ``WAD'' with the length of the wire used for the measurement,
and to refer to WAD [wire length] to refer to the line drawn by using
the wire and the WAD procedure.
S5 Performance and other requirements.
S5.1 Headform impact requirements.
(a) When tested in accordance with the procedures of S6 under the
conditions of S7, subject to the limits of S5.2, when any part of a
vehicle within the Child Headform Test Area or Adult Headform Test Area
is impacted by the headform described in S8, HIC shall not exceed 1,000
(HIC1000).
(b) The HIC in the remaining Child or Adult Headform Test Areas
shall not exceed 1,700 (HIC1700), provided that the manufacturer has
identified HIC1700 Area specified by S5.5(a).
S5.2 Minimum Amount of Child and Adult Headform Test Area that must
conform to HIC1000.
(a) HIC1000 Area in the Combined Child and Adult Headform Test
Areas. Calculate the numerical value of two thirds of the Hood Area
(see S4 for the definition of Hood Area and S6.5.2 for its
determination). At least this amount of area, if it can be placed
within the boundary of the combined Child Headform Test Area (S6.5.3)
and the Adult Headform Test Area (S6.5.4), must be HIC1000 Area. If the
numerical value of two thirds of the Hood Area exceeds the Combined
Child and Adult Headform Test Area, the entire Combined Child and Adult
Headform Test Area must be HIC1000 Area.
(b) HIC1000 Area in Child Headform Test Area. Calculate the
numerical value of one half of the Hood Area with less than WAD1700. At
least this amount of area, when placed within the boundary of the Child
Headform Test Area, must be HIC1000 Area.
S5.3 Multiple simultaneous impact points.
(a) If multiple simultaneous points of initial contact between the
headform and the vehicle occur in more than one area and the areas have
differing HIC requirements, the more stringent requirement applies. For
example, if the initial impact occurs simultaneously within a HIC1700
Area and a HIC1000 Area, the HIC1000 requirement applies. If first
contact occurs simultaneously in both an Adult Headform Test Area and a
Child Headform Test Area, tests with both headforms must be performed
at that location.
S5.5 Border of the HIC1700 Areas in the Hood Area. Under the
authority provided in 49 U.S.C. Chapter 301, 30166, vehicle
manufacturers must make available to NHTSA the following information
upon request.
(a) Manufacturers must identify HIC1700 Areas as described below,
subject to S5.5(b). The HIC1700 Areas will be irrevocably selected
prior to, or at the time of, certification of the vehicle. If no
HIC1700 Area is provided by the manufacturer, NHTSA will test the
Combined Child and Adult Headform Test Area as HIC1000 Area.
(1) Manufacturers must select HIC1700 Areas based on the (x,y)
coordinates of their borders referenced from the intersection of
WAD1000 and the longitudinal centerline of the vehicle. The number of
coordinates and the spacing of the coordinates are provided at the
discretion of the manufacturer, but the points must be joined by
straight lines in the x-y plane when marking off the test areas of an
actual vehicle.
(2) In lieu of (x,y) coordinates, the manufacturer may base the
HIC1700 Area on registration marks referenced from the intersection of
WAD1000 and the vehicle longitudinal centerline and may use decals or
templates for this purpose.
(b)(1) When a HIC1700 Area is contiguous with the HIC Unlimited
Margin as specified in S6.4, the lines identified by NHTSA in
accordance with this standard will supersede any conflicting
coordinates provided by the manufacturer, and will act as border lines
in defining the HIC1700 Area.
(2) Each HIC1700 Area border line must be contiguous. However, the
total HIC1700 Area may consist of an unlimited number of contiguous
areas, provided that the vehicle meets the requirement for HIC1000 Area
specified in S5.2.
S5.6 Active hoods.

[[Page 76986]]

(a) Under the authority provided in 49 U.S.C. 30166, upon NHTSA's
request, vehicle manufacturers must make available to NHTSA information
explaining the basic operational characteristics of their active hood
system.
(b) Vehicles with active hoods shall meet the requirements of this
standard when the hood is fully deployed. The devices to be deployed,
and the minimum and maximum period of time between device deployment
and impact of the headform to assure full deployment at time of impact,
must be irrevocably selected by the manufacturer prior to, or at the
time of, certification of the vehicle, and provided to NHTSA upon
request, under the authority provided in 49 U.S.C. 30166.
(c) All reference lines, HIC Unlimited Margins, and WAD lines
specified in S6.3 must be determined on the vehicle with the hood in
its undeployed state. HIC1700 areas will be identified on the vehicle
with the hood in its undeployed state.
(d) The impact point of the headform is determined with the hood in
an undeployed position.
S5.7 Other movable components.
(a) Other than active devices specified in S5.6, any vehicle
component (such as pop-up headlamps) that could change shape or
position, and that have more than one fixed shape or position, must be
stowed or retracted when determining the reference lines, margins, and
WAD lines specified in S6.3.
(b) The impact point of the headform is determined when the active
devices are in their stowed or retracted position.
S6 Test Procedures.
S6.1 Demonstrate compliance with S5.1 of this standard in
accordance with the test procedures specified in this standard, under
the conditions of S7, using the headforms described in S8. These
procedures are used to identify the Leading Edge Reference Line, Side
Reference Lines, Rear Reference Line, and the WAD lines (S6.3). These
lines are used to identify Hood Area and subsequently the minimum
requisite HIC1000 Area that must be provided. The lines are also used
to identify HIC Unlimited Margins (S6.4) and to identify the Child
Headform Test Area (S6.5.3) and the Adult Headform Test Area (S6.5.4).
NHTSA may request information from the manufacturer in order to
identify the HIC1700 areas (S5.5). The headform is launched at the hood
(S6.6). The child headform must impact within the Child Headform Test
Area and the adult headform must impact within the Adult Headform Test
Area. When a headform strikes a HIC1000 Area, the HIC measured by the
headform must not exceed 1000. When it strikes a HIC 1700 area, HIC
must not exceed 1700.
S6.2 [Reserved]
S6.3 Determining reference lines on the vehicle. Subject to S6.3.5,
the reference lines are determined on the vehicle as follows.
S6.3.1 WAD lines. Determine WAD lines by connecting the end points
of a non-stretch flexible wire as it is traversed across the front of
the vehicle. During this process, the wire must remain in a vertical
longitudinal vehicle plane and held taut. One end of the wire must be
held at the ground reference level, vertically 1 degree,
below the front end of the vehicle, and the other end held in contact
with the hood or fender (see figure 2, provided for illustration
purposes). Determine WAD lines using wires of 1000 1 mm
(the line is referred to as WAD1000), 1700 1 mm (WAD1700)
and of 2100 1 mm (WAD2100).
S6.3.2 Leading Edge Reference Line.
(a) Default procedure. Determine the Leading Edge Reference Line by
connecting the points of contact between a straight edge 1000 1 mm long and the front surface of the vehicle as the straight
edge is traversed laterally across and is in contact with the front end
of the vehicle (see figure 3, provided for illustration purposes).
During this process, the straight edge must be held in a vertical
longitudinal vehicle plane, inclined rearwards by 40 1
degree from the horizontal, and with the lower end 600 5
mm above the ground reference plane. If the straight edge makes a
continuous contact or makes multiple contacts on the vehicle when the
straight edge is at a single lateral location, rerun the procedure with
the straight edge inclined rearwards at an angle of 50 1
degree from the horizontal. For the purpose of determining whether the
straight edge should be held at 50 1 degree from the
horizontal, contacts with a straight edge will be considered continuous
if the total length of contact along the straight edge is greater than
50 mm and the deviation of the contact surface from the straight edge
is less than 0.5 mm. Additionally, contact points must be separated by
at least 50 mm in order to be considered multiple points of contact. If
this procedure results in multiple or continuous points of contact even
after inclining the straight edge rearwards at an angle of 50 1 degree from the horizontal, determine the Leading Edge
Reference Line using the most forward contact.
(b) Low front vehicles. If the vehicle exterior geometry is such
that the bottom end of the straight edge makes first contact with the
vehicle, that contact point is used to determine the Leading Edge
Reference Line at that lateral position. See figure 4, provided for
illustration purposes.
(c) High front vehicles. If the vehicle exterior geometry is such
that the top end of the straight edge makes first contact with the
vehicle, then the WAD1000 line will be used as the Leading Edge
Reference Line at that lateral position. If the WAD1000 line does not
intersect the Side Reference Line determined in S6.3.3 such that the
corner reference point of the Hood Top does not exist, connect the two
lines using the following procedure.
(1) Find the corner reference point of the Hood Top, as if the
Leading Edge Reference Line were determined by the top end of the
straight edge, rather than WAD1000. If this point does not exist, find
the corner reference point of the Hood Top, as if the Leading Edge
Reference Line were determined by the straight edge held at any height.
(2) Span the distance between the corner reference point of the
Hood Top and the WAD1000 line with a non-stretch flexible wire held
taut in the vertical longitudinal plane.
(3) Fill the discontinuity by establishing a line created by the
projection of the wire horizontally rearward onto the vehicle surface.
S6.3.3 Side Reference Lines. These lines are determined on the
vehicle by connecting the points of contact between a straight edge 700
1 mm long and the vehicle, as the straight edge is
traversed fore or aft, in contact with the sides of the vehicle (see
figure 5, provided for illustration purposes). During this process, the
straight edge must be held in a vertical transverse vehicle plane,
inclined inwards by 45 1 degrees from the horizontal. If
this procedure results in multiple or continuous points of contact on
the vehicle when the straight edge is at a single fore-aft location,
determine the Side Reference Line by using the most outboard contact.
S6.3.4 Rear Reference Line.
(a) Default procedure. This line is determined on the vehicle by
connecting the most rearward points on the hood that contact a 165
1 mm diameter hemisphere as it is traversed laterally
across the vehicle while maintaining contact with the windshield (see
figure 6, provided for illustration purposes). The wiper blades,
linkages, and arms are removed during this process. If this procedure
results in multiple or continuous points of contact

[[Page 76987]]

on the vehicle when the hemisphere is at a single lateral location,
determine the Rear Reference Line by using the most rearward contact.
This section is subject to S6.3.4(b).
(b) Revision of a Rear Reference Line when not intersecting with a
Side Reference Line.
(1) Where the rear reference line and the side reference line do
not intersect, the rear reference line must be extended and/or modified
using a semi-circular template of radius 100 1 mm. The
template must be made of a thin flexible sheet material that easily
bends to a single curvature in any direction. The template must resist
double or complex curvature where this could result in wrinkling. The
template is marked with four points ``A'' through ``D,'' as shown in
figure 8 (provided for illustration purpose), while the template is on
a flat surface.
(2) The template must be placed on the vehicle with Corners ``A''
and ``B'' coincident with the Side Reference Line. Ensuring these two
corners remain coincident with the Side Reference Line, the template
must be slid progressively rearwards until the outer edge of the
template makes first contact with the Rear Reference Line. Throughout
the process, the template must be curved to follow, as closely as
possible, the outer contour of the vehicle's hood and fender without
wrinkling or folding of the template. If the first point of contact
between the template and Rear Reference Line lies outside the arc
identified by points ``C'' and ``D,'' the Rear Reference Line is
extended and/or modified to follow the circumferential arc of the
template to meet the Side Reference Line, as shown in figure 9
(provided for illustration purposes).
(3) Larger template. If the outer edge of the template of
S6.34(b)(1) cannot make contact with the Rear Reference Line while
simultaneously the Side Reference Line contacts points ``A'' and ``B,''
or the point at which the Rear Reference Line and template make first
contact lies within the arc identified by points ``C'' and ``D,'' then
additional templates will be used where the radii are increased
progressively in increments of 20 mm, until all the criteria of
S6.3.4(b)(2) are met.
S6.3.5 Adjustments to the procedures determining the reference
lines.
(a) Line discontinuity. If the Leading Edge Reference Line, Side
Reference Line(s) or Rear Reference Line are discontinuous (i.e., the
procedure has resulted in a gap in a line), the discontinuity will be
spanned by the following method. Connect the two points separated by
the discontinuity with a non-stretch flexible wire held taut. Fill the
discontinuity by establishing a line created by the projection of the
wire vertically downward onto the hood surface.
(b) Hood ornaments. If the vehicle is fitted with a badge, emblem,
hood ornament, or other structure which would bend back or retract
under an applied load of maximum 100 5 N, apply this load
while the reference lines are defined on the hood. The load must be
released prior to testing with a headform.
S6.4 HIC Unlimited Margins.
S6.4.1 HIC Unlimited Margin of the Rear Reference Line. The HIC
Unlimited Margin of the Rear Reference Line is the line that is
forwardmost of the following two lines.
(a) The line on the vehicle determined by connecting the points of
contact between a non-stretch flexible wire measuring 82.5
0.5 mm long as it is traversed along the Rear Reference Line. During
this process, the wire remains in a vertical longitudinal vehicle plane
and held taut. One end of the wire is held in contact with the Rear
Reference Line and the other end is held in contact with the vehicle at
points forward of the Rear Reference Line.
(b) The WAD2100 Line.
S6.4.2 HIC Unlimited Margin of the Leading Edge Reference Line. The
HIC Unlimited Margin of the Leading Edge Reference Line is the line
that is rearmost of the following two lines.
(a) The line on the vehicle determined by connecting the points of
contact between a non-stretch flexible wire measuring 82.5
0.5 mm long as it is traversed along the Leading Edge Reference Line.
During this process, the wire remains in a vertical longitudinal
vehicle plane and held taut. One end of the wire is held in contact
with the Leading Edge Reference Line and the other end is held in
contact with the vehicle and points rearward of the Leading Edge
Reference Line.
(b) The WAD1000 Line.
S6.4.3 HIC Unlimited Margin of the Side Reference Lines. This HIC
Unlimited Margin is the line determined by connecting the points of
contact between a non-stretch flexible wire measuring 82.5
0.5 mm long as it is traversed along the Side Reference Line. During
this process, the wire remains in a vertical lateral plane and held
taut. One end of the wire is held in contact with the Side Reference
Line and the other end held is in contact with the vehicle and points
inward of the Side Reference Line.
S6.5 Hood Top, Hood Area, Child Headform Test Area and Adult
Headform Test Area border lines and computation method. The border
lines for the Hood Top, Hood Area, the Child Headform Test Area, and
the Adult Headform Test Area are identified as described in this
section. Computation of these areas is made on the basis of a two-
dimensional projection of these areas on to a horizontal vehicle plane.
These areas include those comprised of any ``non-contactable surfaces''
(as defined in S4) in their computation.
S6.5.1 Hood Top. This area is enclosed by the intersection of the
following borders:
(a) Front border: Leading Edge Reference Line;
(b) Side border: Side Reference Lines.
(c) Rear border: Rear Reference Line.
S6.5.2 Hood Area. This area is enclosed by the intersection of the
following borders:
(a) Front border: the Leading Edge Reference Line or the WAD1000
line, whichever is most rearward at the point of measurement;
(b) Side border: Side Reference Lines.
(c) Rear border: Rear Reference Line, or the WAD2100 line,
whichever is most forward at the point of measurement.
S6.5.3 Child Headform Test Area. This area is enclosed by the
intersection of the following borders:
(a) Front border: HIC Unlimited Margin of the Leading Edge
Reference Line.
(b) Side borders: HIC Unlimited Margins of the Side Reference
Lines.
(c) Rear border: WAD1700 line or the HIC Unlimited Margin of the
Rear Reference Line, whichever is most forward at the point of
measurement.
S6.5.4 Adult Headform Test Area. This area is enclosed by the
intersection of the following borders:
(a) Front border: WAD1700 line.
(b) Side borders: HIC Unlimited Margins of the Side Reference
Lines.
(c) Rear border: HIC Unlimited Margin of the Rear Reference Line.
S6.6 Headform launch procedures.
(a) Propulsion of the headform. The headform must be in free flight
at the moment of impact. The headform velocity at the time of impact
must be 9.7 0.2 meters per second (m/s) for both the child
and adult headforms.
(b) Child headform test procedure.
(1) At least one impact point against which the child headform
contacts must be in the Child Headform Test Area.
(2) The velocity vector of the headform center of mass at impact is
in a longitudinal vertical vehicle plane at an angle of 50
2[deg] to the horizontal directed downward and rearward.
(c) Adult headform test procedure.
(1) At least one impact point against which the adult headform
contacts must be in the Adult Headform Test Area.

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(2) The velocity vector of the headform center of mass at impact is
in a longitudinal vertical vehicle plane at an angle of 65
2[deg] to the horizontal directed downward and rearward.
S7 General test conditions.
S7.1 Humidity and temperature. At the time of testing, the ambient
air at the test site must have a relative humidity of 40 percent 30 percent and a temperature of 20 4 [deg]C.
S7.2 Test site. The test site is on a ground reference plane
consisting of a flat, smooth and hard surface with a grade not
exceeding 1 percent.
S7.3. Vehicle preparation.
(a) Normal ride attitude. The vehicle is positioned on the ground
reference plane, loaded to its unloaded vehicle weight, and tires
inflated to the pressures listed on the vehicle's FMVSS No. 110 (49 CFR
571.110) placard. The front wheels are aligned to be parallel to the
vehicle vertical longitudinal plane, the suspension set to the normal
running condition as specified by the manufacturer for a speed of 40
km/hr, and the parking brake applied.
(b) Additional mass. Place a 75 5 kg mass at each most
outboard front row seat. The fore-aft position of a loaded seat must be
set at the mid-track position. If there is no notch at the mid-track
position, the seat is set at the notch closest to and rearward of mid-
track, with respect to the direction the seat is facing. Set the seat
back angle to a position between the most upright position intended for
occupancy to 10 degrees rearward of that position, with respect to the
direction the seat is facing.
(c) Movable front-end vehicle components.
(1) Active hoods and devices. Active hoods, external air bags, and
other devices designed to protect pedestrians are deployed prior to
launching the headform.
(2) Other movable components. Other than active devices specified
in S6.3, any vehicle component (such as pop-up headlamps) that could
change shape or position, and that have more than one fixed shape or
position, are adjusted to any fixed shape or position prior to
launching the headform.
S8. Headform specifications
(a) Dynamic performance requirements.
(1) Qualification. The headforms must meet the dynamic
qualification requirements specified in S8.4.
(2) First natural frequency. The first natural frequency of the
headforms must be over 5000 Hz.
S8.1 Construction.
(a) The child and adult headforms are made of aluminum, are of
homogenous construction and are hemispherical in shape. The headforms
are schematically represented in figures 11 and 12 and detailed
mechanical drawings are provided in figures 13-26. The overall diameter
of the headforms are 165 1 mm.
(b) Mass properties of child headform (figure 13). The mass of the
child headform is 3.5 0.07 kg. The moment of inertia about
an axis through the center of gravity and perpendicular to the
direction of impact is within the range of 0.008 to 0.012 kgm\2\. The
center of gravity of the headform including instrumentation is located
in the geometric center of the sphere with a tolerance of 2
mm.
(c) Mass properties of adult headform (figure 20). The mass of the
adult headform is 4.5 0.1 kg. The moment of inertia about
an axis through the center of gravity and perpendicular to the
direction of impact is within the range of 0.010 to 0.013 kgm\2\. The
center of gravity of the headform including instrumentation is located
in the geometric center of the sphere with a tolerance of
5 mm.
(d) Cover (figures 15 and 22). The headforms are covered with a 14
0.5 mm thick synthetic skin, which must cover at least
half of the hemisphere.
(e) Back plate (figures 17 and 24). The headforms each have a rear
flat face perpendicular to the direction of travel and the axis of one
of the accelerometers. The flat face provides access to the
accelerometers and serves as an attachment point for the propulsion
system.
S8.2 Instrumentation mount. A recess within the headforms allows
for mounting three uniaxial accelerometers. For each accelerometer, the
seismic mass is located within 5 mm of the headform's
centroid as measured along its measurement axis, and within 0.5 mm as measured perpendicular to its measurement axis.
S8.3 Instrumentation.
(a) Three uniaxial accelerometers are installed within the
headforms. One of the accelerometers has its sensitive axis
perpendicular to mounting face A (see figures 11 and 12) and its
seismic mass is positioned within a cylindrical tolerance field of 1 mm
radius and 20 mm length. The centerline of the tolerance field runs
perpendicular to the mounting face and its mid-point coincides with the
spherioidal center of the headform.
(b) The remaining accelerometers have their sensitive axes
perpendicular to each other and parallel to mounting face A and their
seismic masses are positioned within a spherical tolerance field of 10
mm radius. The center of the tolerance field coincides with the
spheroidal center of the headform.
(c) The accelerometers have the dimensions, response
characteristics, and sensitive mass locations specified in drawing
SA572-S5 (figure 27). The instrumentation response value Channel
Frequency Class (CFC), as defined in SAE J211 (2022), ``Instrumentation
for Impact Test,'' (incorporated by reference, see Sec. 571.5), is CFC
1000.
S8.4 Qualification requirements
(a) Peak acceleration. For each of the three drop tests prescribed
in S8, the peak resultant acceleration in the headform must be:
(1) for the child headform, not less than 245 g and not more than
300 g;
(2) for the adult headform, not less than 225 g and not more than
275 g.
(b) Unimodal response. For each of the three drop tests, the
acceleration must be unimodal to the extent that oscillations occurring
after the main acceleration pulse are less than ten percent (zero to
peak) of the main pulse.
(c) Off-axis sensitivity. The lateral acceleration must not exceed
15 g (zero to peak).
S8.5 Qualification procedure
(a) Temperature and humidity. The headforms must have a temperature
of 20 2 [deg]C. The temperature tolerances apply at a
relative humidity of 40 30 percent after a soak period of
at least four hours prior to their application in a test.
(b) Drop test. (1) Drop rig. The headform is suspended from a drop
rig as shown in figure 12 (provided for illustration purposes) and
released by a means to ensure that it does not rotate during the fall.
The headform is set up to strike a rigidly supported flat horizontal
steel plate, over 50 mm thick and over 300 x 300 mm square with a
surface finish of between 0.2 and 2.0 micrometers. The plate is 0.5 degrees from horizontal. The headform skin outer surface and
the surface of the steel plate are cleaned with 1,1,1 trichloroethane
or equivalent and allowed to dry.
(2) Drop angle. The headform must be oriented as shown in figure 10
(provided for illustration purposes) with the rear face of the headform
at the following angles from the vertical:
(i) 50 2 degrees for the child headform;
(ii) 65 2 degrees for the adult headform.
(3) Drop height. The headform is dropped from a height of 376
1 mm.
(i) Initial drop. The drop is performed with the headform oriented
such that the plane formed by the travel direction vector and the
symmetric axis of the headform is perpendicular within 2

[[Page 76989]]

degrees to the sensitive axis of one of the accelerometers.
(ii) Repeat drops. The drop test is performed two additional times,
with the headform rotated 120[deg] around its symmetrical axis after
each test with a two-hour wait period between tests.
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Issued in Washington, DC, under authority delegated in 49 CFR
1.95 and 501.5.
Sophie Shulman,
Deputy Administrator.
[FR Doc. 2024-20653 Filed 9-18-24; 8:45 am]
BILLING CODE 4910-59-C