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Proposed Rule2024-20653

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

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Published

September 19, 2024

Issuing agencies

Transportation DepartmentNational Highway Traffic Safety Administration

Abstract

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.

Full Text

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[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 [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-20653]

[[Page 76921]]

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

[[Page 76922]]

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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:
<bullet> Federal eRulemaking Portal: Go to <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the online instructions for submitting
comments.
<bullet> 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.
<bullet> 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 <a href="https://www.regulations.gov">https://www.regulations.gov</a>, including any personal information
provided.
Docket: For access to the docket to read background documents or
comments received, go to <a href="http://www.regulations.gov">www.regulations.gov</a>, 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

[[Page 76923]]

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
(<a href="https://www.iihs.org/news/detail/three-more-automakers-fulfill-pledge-to-make-autobrake-nearly-universal">https://www.iihs.org/news/detail/three-more-automakers-fulfill-pledge-to-make-autobrake-nearly-universal</a>). Other agency data
indicate about 87% of production has PAEB. <a href="https://www.transportation.gov/NRSS/SaferVehicles">https://www.transportation.gov/NRSS/SaferVehicles</a>. 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. <a href="https://www.nhtsa.gov/sites/nhtsa.gov/files/documents/812400_pcambenefitsreport.pdf">https://www.nhtsa.gov/sites/nhtsa.gov/files/documents/812400_pcambenefitsreport.pdf</a>.
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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

[[Page 76924]]

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

<bullet> 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.
<bullet> Dart-out (second half)--similar to the Dart-out (first
half) except the pedestrian is struck after crossing half or more of
the roadway.
<bullet> 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.
<bullet> 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).
<bullet> 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\ <a href="https://www.nhtsa.gov/road-safety/pedestrian-safety">https://www.nhtsa.gov/road-safety/pedestrian-safety</a>.
\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). <a href="https://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29glob/globale.pdf">https://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29glob/globale.pdf</a>. 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). <a href="https://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29glob/globale.pdf">https://www.unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29glob/globale.pdf</a>.
\52\ <a href="https://unece.org/fileadmin/DAM/trans/doc/2004/wp29/TRANS-WP29-AC3-07e.pdf">https://unece.org/fileadmin/DAM/trans/doc/2004/wp29/TRANS-WP29-AC3-07e.pdf</a>.
---------------------------------------------------------------------------

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. <a href="https://unece.org/transport/standards/transport/vehicle-regulations-wp29/global-technical-regulations-gtrs">https://unece.org/transport/standards/transport/vehicle-regulations-wp29/global-technical-regulations-gtrs</a>.
\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 <plus-minus> 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 <plus-minus> 1 mm (``WAD1700'') and
2100 <plus-minus> 1 mm (``WAD2100'').\60\ See figure V.1, below,
illustrating how WAD is measured.
---------------------------------------------------------------------------

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

\61\ Paragraph 71 of the ``Safety Need'' section of GTR 9.
<a href="https://unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29registry/ECE-TRANS-180a9e.pdf">https://unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29registry/ECE-TRANS-180a9e.pdf</a>.
[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:
<bullet> Relevance to the vehicles involved in pedestrian crashes
at 40 km/h (25 mph);
<bullet> A methodology incorporating component testing of the hood
using headforms representing child and adult pedestrians;
<bullet> Performance requirements based on HIC as measured by the
headforms;
<bullet> A hood mark-off procedure to denote test areas; and
<bullet> 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\ <a href="https://www.goodcarbadcar.net/2021-us-commercial-van-sales-figures-by-model/">https://www.goodcarbadcar.net/2021-us-commercial-van-sales-figures-by-model/</a>.
\66\ <a href="https://www.goodcarbadcar.net/2021-us-vehicle-sales-figures-by-model/">https://www.goodcarbadcar.net/2021-us-vehicle-sales-figures-by-model/</a>.
---------------------------------------------------------------------------

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). <a href="https://unece.org/DAM/trans/doc/2008/wp29/WP29-144-03e.pdf">https://unece.org/DAM/trans/doc/2008/wp29/WP29-144-03e.pdf</a>.

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, a<INF>r</INF>, 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
<bullet> 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.
<bullet> 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.
BILLING CODE 4910-59-P

[[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.
<bullet> 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] <plus-minus> 2[deg] at the time of
impact). For the adult headform, the

[[Page 76936]]

angle would be 65 degrees (65[deg] <plus-minus> 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
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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.
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\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
<bullet> 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):
<bullet> Front border: Leading Edge Reference Line.
<bullet> Side border: Side Reference Lines.
<bullet> 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 <plus-minus> 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. <a href="https://www.acea.auto/acea-members/">https://www.acea.auto/acea-members/</a>.
---------------------------------------------------------------------------

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

<bullet> Front border: the Leading Edge Reference Line (LERL) or
the WAD1000 line, whichever is most rearward at the point of
measurement;
<bullet> Side border: Side Reference Lines (SRL).
<bullet> Rear border: Rear Reference Line (RRL), or the WAD2100
line, whichever is most forward at the point of measurement.
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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.
<a href="https://unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29registry/ECE-TRANS-180a9e.pdf">https://unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29registry/ECE-TRANS-180a9e.pdf</a>.
---------------------------------------------------------------------------

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
[GRAPHIC] [TIFF OMITTED] TP19SE24.018

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:
<bullet> 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.
---------------------------------------------------------------------------

<bullet> Side borders: HIC Unlimited Margins of the Side Reference
Lines.
<bullet> 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:
<bullet> Front border: WAD1700 line.
<bullet> Side borders: HIC Unlimited Margins of the Side Reference
Lines.
<bullet> Rear border: HIC Unlimited Margin of the Rear Reference
Line.\103\
BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TP19SE24.019

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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[[Page 76950]]

[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.

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

[[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. <a href="https://www.euroncap.com/en/for-engineers/supporting-information/technical-bulletins/">https://www.euroncap.com/en/for-engineers/supporting-information/technical-bulletins/</a>. 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.
<bullet> 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.
---------------------------------------------------------------------------

<bullet> 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.
<bullet> 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.
<bullet> 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
<bullet> 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 <a href="https://tools.openlab.psu.edu/tools/explorer.php">https://tools.openlab.psu.edu/tools/explorer.php</a>.
---------------------------------------------------------------------------

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

<bullet> 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.
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\118\ Euro NCAP Vulnerable Road User Testing Protocol <a href="https://cdn.euroncap.com/media/70319/euro-ncap-vru-testing-protocol-v901.pdf">https://cdn.euroncap.com/media/70319/euro-ncap-vru-testing-protocol-v901.pdf</a>.
---------------------------------------------------------------------------

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

<bullet> 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.
<bullet> 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.
<bullet> 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:
<bullet> 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.
<bullet> 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.
<bullet> 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.
<bullet> 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
<bullet> 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

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