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



[[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  

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

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


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

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

ACTION: Notice of proposed rulemaking (NPRM).

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

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

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

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

SUPPLEMENTARY INFORMATION:

Table of Contents

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

I. Executive Summary

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

[[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 
(https://www.iihs.org/news/detail/three-more-automakers-fulfill-pledge-to-make-autobrake-nearly-universal). Other agency data 
indicate about 87% of production has PAEB. https://www.transportation.gov/NRSS/SaferVehicles. The voluntary commitment 
did not involve a pedestrian AEB component. NHTSA's NPRM would 
require an AEB system that detects and reacts to both lead vehicles 
and pedestrians and would increase the lead-vehicle performance 
required of AEB over that described in the voluntary commitment.
    \6\ Yanagisawa, M., Swanson, E., Azeredo, P., & Najm, W.G. 
(2017, April). Estimation of potential safety benefits for 
pedestrian crash avoidance/mitigation systems. (Report No. DOT HS 
812 400). Washington, DC: National Highway Traffic Safety 
Administration. https://www.nhtsa.gov/sites/nhtsa.gov/files/documents/812400_pcambenefitsreport.pdf.
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    This NPRM proposes FMVSS No. 228 and aligns with the goals of DOT's 
January 2022 National Roadway Safety Strategy, which describes the five 
key objectives of the Department's Safe System Approach: safer people, 
safer roads, safer vehicles, safer speeds, and post-crash care. FMVSS 
No. 228 would mandate requirements for safer vehicles and leverage 
advanced crash avoidance technology like PAEB in conjunction with the 
crashworthiness countermeasures based on GTR 9 to realize far-reaching 
improvements to pedestrian safety. NHTSA also notes that although 
research into vulnerable

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

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

[[Page 76925]]

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

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

[[Page 76926]]

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

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

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

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

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

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


[[Page 76927]]

II. Safety Need

    In 2020, 38,824 people died on U.S. roads. Of this number, 25,536 
were passenger vehicle occupant fatalities, a decrease from 32,225 in 
2000.\26\ This reduction is notable, particularly in light of the fact 
that the total number of vehicle miles traveled (VMT) in the U.S. has 
increased over time. However, during that same timeframe, pedestrian 
fatalities increased by 33 percent, from 4,739 in 2000 to 6,516 in 
2020.27 28
---------------------------------------------------------------------------

    \26\ Traffic Safety Facts 2020 ``A Compilation of Motor Vehicle 
Crash Data.'' U.S. Department of Transportation. National Highway 
Traffic Safety Administration.
    \27\ Traffic Safety Facts 2000 ``A Compilation of Motor Vehicle 
Crash Data from the Fatality Analysis Reporting System and the 
General Estimates System.'' U.S. Department of Transportation. 
National Highway Traffic Safety Administration.
    \28\ National Center for Statistics and Analysis. (2021, 
October), Early Estimate of Motor Vehicle Traffic Fatalities for the 
First Half (January-June) of 2021. (Traffic Safety Facts. Report No. 
DOT HS 813 199), Washington, DC: National Highway Traffic Safety 
Administration.
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    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.
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    \29\ NHTSA Fatality Analysis Reporting System (FARS).
    \30\ Swanson, E., Foderaro, F., Yanagisawa, M., Najm, W.G., & 
Azeredo, P. (2019, August). Statistics of light-vehicle pre-crash 
scenarios based on 2011-2015 national crash data (Report No. DOT HS 
812 745). Washington, DC: National Highway Traffic Safety 
Administration.
---------------------------------------------------------------------------

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

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

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

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

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

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

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

[[Page 76928]]



    Table II.1--Pedestrian Injuries and Fatalities in Single Vehicle Front End Crashes by Vehicle Type, 2020
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
Class of vehicle                                             Injuries
                                                            Fatalities
----------------------------------------------------------------------------------------------------------------
Passenger car...................................    23,158 (58%)    38,961 (98%)     1,972 (43%)     3,941 (85%)
Light Truck and MPV.............................    15,803 (40%)                     1,969 (42%)
                                                 ---------------------------------------------------------------
Large Truck.....................................
                                                             274 (6%)
Bus.............................................
                                                             21 (0.5%)
Unknown/other...................................             959 (2%)
                                                             386 (8%)
Totals (front end)..............................           39,921 (100%)
                                                           4,622 (100%)
Totals (all impact locations)...................              50,397
                                                               5,536
----------------------------------------------------------------------------------------------------------------
Sources: NHTSA's Fatal Accident Reporting System (FARS) and National Automotive Sampling System--General
  Estimates System (GES). NHTSA's Traffic Safety Facts Sheet.

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

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

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

III. Foundations for the Proposal

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

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

NHTSA's Efforts on a Pedestrian Head Protection Standard

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

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

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

[[Page 76929]]

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

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

IV. The Global Technical Regulation

A. Introduction

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

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

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

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

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

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

B. GTR 9

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

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

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

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

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

[[Page 76930]]

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

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

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

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

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

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

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

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

V. Approach of the Proposed Standard

A. Overview

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

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

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

[[Page 76931]]

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

    A WAD line can be objectively determined and is a good indicator of 
where head impacts are likely to occur on any particular hood.\61\ The 
WAD measurement accounts for both pedestrian height and vehicle front-
end configuration. That is, in a 40 km/h crash, a given pedestrian's 
head-to-hood contact point is approximated by the WAD that corresponds 
to the pedestrian's standing height.
---------------------------------------------------------------------------

    \61\ Paragraph 71 of the ``Safety Need'' section of GTR 9. 
https://unece.org/fileadmin/DAM/trans/main/wp29/wp29wgs/wp29gen/wp29registry/ECE-TRANS-180a9e.pdf.
[GRAPHIC] [TIFF OMITTED] TP19SE24.003

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

B. Relevance to the Involved Vehicles

    FMVSS No. 228 would apply to passenger cars, and to MPVs, trucks, 
and buses with a GVWR of 4,536 kg (10,000 lb) or less, except for 
vehicles with short front ends (a very short front hood area). Proposed 
FMVSS No. 228 would also apply to bidirectional vehicles, i.e., 
vehicles that can be operated in either direction. We discuss these 
issues below.
Vehicles With Short Front Ends
    Reflecting the text of GTR 9, the NPRM's proposed regulatory text 
(S3) excludes MPVs, trucks, and buses where the distance, measured 
longitudinally on a horizontal plane, between the transverse centerline 
of the front axle and the seating reference point (SgRP) of the 
driver's seat, is less than 1,000 mm.\62\ In the statement of technical 
rationale for GTR 9, the drafters argued that these vehicles have a 
very short hood and a front shape that is very close to vertical, so 
the pedestrian kinematics with these vehicles are believed to be very 
different than a collision with a vehicle with a longer hood. The 
drafters also concluded that there are difficulties in applying the 
tests to these vehicles, particularly regarding the determination of 
test zone reference lines.
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    \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.
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    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.
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    \64\ Some vehicles in this category would be the Chevrolet 
Express, Ford E-Series, Ford Transit, Ford Transit Connect, GMC 
Savana, Mercedes-Benz Metris, Mercedes-Benz Sprinter, Nissan NV, 
Nissan NV200, Ram ProMaster, Ram ProMaster City.
    \65\ https://www.goodcarbadcar.net/2021-us-commercial-van-sales-figures-by-model/.
    \66\ https://www.goodcarbadcar.net/2021-us-vehicle-sales-figures-by-model/.
---------------------------------------------------------------------------

    NHTSA has tested a vehicle with a short front end similar to 
vehicles in the excluded category and has successfully conducted 
headform testing. This testing demonstrated that the proposed WAD-based 
test procedure can be applied to short front end vehicles. NHTSA also 
believes it would be practicable for the vehicles to meet the proposed 
standard. NHTSA tested the 2004 GMC Savana van to a slightly modified 
version of the GTR 9 test protocol, with a 32 km/h head impact speed. 
Three of four hood impacts had a HIC below 600. The fourth test, near 
the edge of the hood had a HIC of less than 1000.\67\ These results 
suggest that FMVSS No. 228 would be practicable for similar vehicles.
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    \67\ Stammen J, et al, ``Pedestrian Head Safety Survey of U.S. 
Vehicles In Support of the Proposed Global Technical Regulation 
(GTR)'' (2006). https://unece.org/DAM/trans/doc/2008/wp29/WP29-144-03e.pdf.

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

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

[[Page 76933]]

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

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

C. Advantages of Headform Component Tests

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

D. Head Injury Criterion (HIC)

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

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

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

    Proposed FMVSS No. 228 would require vehicles to meet HIC limits 
when subjected to hood headform impactor testing. It defines the 
forward, rear and side areas of the hood, thus defining a primary 
area--the ``Hood Top.'' \71\ From there, a typically smaller ``Hood 
Area'' is defined using, among other things, the Wrap Around Distance 
lines described earlier. Of this Hood Area, the standard would define a 
Child Headform Test Area and an Adult Headform Test Area, excluding 
margins at the side and potentially at the front and rear, which would 
be tested with the child and adult headforms, respectively. The HIC 
must not exceed 1000 (HIC1000) over a certain portion of the Child and 
Adult Headform Test Areas, as a percentage of the overall Hood Area. 
Specifically, the portion of the Child Headform Test Area that must 
meet the HIC1000 provision must be at least one-half of the numerical 
value of the Hood Area with a Wrap Around Distance of less than 1,700 
mm (WAD1700).\72\ Secondly, the portion of the Combined Child and Adult 
Headform Test Areas that must not exceed the HIC1000 provision must be 
at least two-thirds of the numerical value of the Hood Area. For 
practicability reasons to accommodate a manufacturing need to reinforce 
and stiffen the hood edges, the remaining test area is permitted to 
have HIC higher than 1000, but nonetheless limited to 1700 for both 
headforms.\73\
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    \71\ The procedures for defining these areas are discussed below 
in this preamble.
    \72\ The drafters of the GTR determined that because the 
location of necessary under-hood components cannot be fundamentally 
changed, it is unavoidable that they are located in the child 
headform test area. Thus, the GTR provides that the relaxation zone 
for the child headform test area may be half of the zone (as opposed 
to \1/3\ of the zone, as in the adult test area).
    \73\ Such reasons include the need to minimize any fluttering of 
the hood at high speeds and the ability to slam the hood shut 
without deforming the seams at the junction of the hood and fender.
---------------------------------------------------------------------------

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

[[Page 76934]]

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

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

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

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

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

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

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

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

[GRAPHIC] [TIFF OMITTED] TP19SE24.005

BILLING CODE 4910-59-C
    Notwithstanding the proposed headform test speed of 35 km/h (22 
mph), NHTSA believes there would be benefits from the proposed standard 
for some crashes above a 40 km/h (25 mph) vehicle speed, as the 
countermeasures used to meet the proposed HIC thresholds could mitigate 
some of the harm resulting from head-to-hood strikes that can occur in 
the higher speed crashes. Also, vehicle designs that provide head 
protection in a 35 km/h (22 mph) headform impact may also have the 
effect of reducing the severity of injuries to body regions other than 
the head in collisions at vehicle speeds above 40 km/h (25 mph). For 
example, at vehicle to pedestrian collision speeds of 50 km/h (31 mph) 
and higher, bi-lateral rib fractures have been observed in thorax-to-
hood contacts.\78\ We request comment on whether some of these types of 
injuries could be mitigated by hood designs meeting FMVSS No. 228.
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    \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.
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    NHTSA anticipates PAEB would mitigate 238 fatalities and 2,672 
injuries of the current target population for this NPRM and has based 
our benefits estimate for this NPRM on that assumption. Automatic 
emergency braking helps prevent crashes or reduce their severity by 
applying a vehicle's brakes automatically. The systems use on-board 
sensors to detect an imminent crash, warn the driver, and apply the 
brakes if the driver does not take action quickly enough or increase 
the braking application in the case that the driver does not 
sufficiently brake to avoid contact. When new vehicles are equipped 
with PAEB that meets the requirements specified in FMVSS No. 127, fewer 
pedestrians will be struck, which would have the effect of reducing the 
target population for this rulemaking. On the other hand, for many 
impacts that occur at speeds too high for PAEB to completely mitigate, 
PAEB will lower the vehicle's speed so that impact speeds that would 
have been greater than 40 km/h (25 mph) could be reduced to close to or 
below 40 km/h (25 mph). This would theoretically add to the target 
population of this rulemaking because these are pedestrian crashes that 
this proposed pedestrian head protection standard could potentially 
address. And, as proposed FMVSS No. 228 would ensure the striking 
vehicles have protective features that protect against serious to fatal 
head injury in these impacts, those pedestrians that would be newly 
included in the target population of this NPRM due to PAEB could 
arguably be included among those saved from serious to fatal injury by 
this head protection rulemaking. However, we have not accounted for the 
extent to which the FMVSS No. 127 would add to the target population or 
to the population of persons benefiting from this head protection NPRM 
because of unknowns about how those benefits could be quantified. As a 
result, our analysis likely underestimates benefits. With this in mind, 
in the PRIA we estimate that PAEB would decrease the fatality target 
population addressed by FMVSS No. 228 by about 4 percent. Comments are 
requested on this issue.
     NHTSA requests comments on increasing the test velocity 
above 35 km/h (22 mph) to capture a greater percentage of pedestrian 
impacts presented in the field data and achieve additional safety 
benefits.
2. Headform Impact Angle
    Consistent with the GTR, NHTSA proposes that, at impact, the 
velocity vector of the child headform would form a 50-degree angle down 
from the horizontal (50[deg]  2[deg] at the time of 
impact). For the adult headform, the

[[Page 76936]]

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

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

[[Page 76937]]

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

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

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

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

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

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

VI. Defining the Relevant Areas Subject to the Standard

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

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

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

A. Determining the Hood Top

    The Hood Top is enclosed by the intersection of the following 
borders (these borders are depicted in figure VI.1 below):
     Front border: Leading Edge Reference Line.
     Side border: Side Reference Lines.
     Rear border: Rear Reference Line.
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[[Page 76938]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.007

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]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.008

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

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

[[Page 76941]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.011

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

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

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

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

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[[Page 76942]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.012

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

[[Page 76943]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.013

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

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

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

[[Page 76944]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.014

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

[[Page 76945]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.015

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

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

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[[Page 76946]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.016

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

B. Hood Area

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

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

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

[[Page 76947]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.017

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

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

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

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

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

[[Page 76948]]

WAD2100 or the RRL in determining the rear border of the Hood Area. For 
most passenger cars, WAD2100 falls rearward of the cowl so the rear 
border would be the RRL. However, WAD2100 could define the rear border 
on some larger vehicles. Figure VI.12, below, shows an example of the 
WAD2100 line defining the rear edge of the Hood Area, rather than the 
RRL. Again, the cross hatched area shows the difference between the 
Hood Top and Hood Area. As we discuss below, the rear border of the 
Hood Area may not necessarily be the rear border of the Adult Headform 
Test Area. In section VI.C.5, we discuss using WAD2500 rather than 
WAD2100 as the rear reference line for the Adult Headform Test Area. 
(Conforming changes would be reflected in the rear border of the Hood 
Area if such a change were made.)
BILLING CODE 4910-59-P
[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.
---------------------------------------------------------------------------

    \101\ As explained previously, the standard would provide for 
HIC Unlimited Areas as a practicability measure to accommodate a 
manufacturing need to reinforce and stiffen the hood edges.
---------------------------------------------------------------------------

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

     Side borders: HIC Unlimited Margins of the Side Reference 
Lines.
     Rear border: WAD1700 line or the HIC Unlimited Margin of 
the Rear Reference Line, whichever is most forward at the point of 
measurement.
    The Adult Headform Test Area (See figure VI.13) is enclosed by the 
intersection of the following borders:
     Front border: WAD1700 line.
     Side borders: HIC Unlimited Margins of the Side Reference 
Lines.
     Rear border: HIC Unlimited Margin of the Rear Reference 
Line.\103\
BILLING CODE 4910-59-P
[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).
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    \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.
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    \105\ 2021 Wards Automotive.

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[[Page 76952]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.022

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

[[Page 76953]]

means the impact would be 50 degrees from purely perpendicular. 
However, striking a grille in this manner would constitute a slightly 
less direct impact and presumably a less severe test. We believe that, 
in a real-world impact, the head of a child striking such a high front 
end vehicle would have a trajectory more in line with the velocity 
vector of the vehicle than the current launch angle of the child 
headform. The Euro NCAP procedure and NHTSA's NCAP RFC allow for test 
points on the front surface of the vehicle. Euro NCAP and the NCAP RFC 
make an adjustment to the impact direction to 20 degrees when forward 
of the LERL so as to produce a more perpendicular impact. Additionally, 
if the LERL is between WAD930 and WAD1000, Euro NCAP monitors this 
location with a 20-degree impact test performed at the LERL.\106\ NHTSA 
plans to conduct research on headform testing in the grille area of 
some pickup trucks using the proposed FMVSS No. 228 protocol to assess 
its practicality, as well as the merits of a more direct 
(perpendicular) impact. As discussed in the next section, depending on 
the results, the final rule may adjust the impact angle of the headform 
when the test is conducted in the grille area.
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    \106\ Monitors means the results could be called out but are not 
part of the Euro NCAP scoring. See, Technical Bulletin 019--Headform 
to Bonnet Leading Edge. https://www.euroncap.com/en/for-engineers/supporting-information/technical-bulletins/. This bulletin explains 
that the result of this test will be monitored against a HIC value 
of 650. Where a ``poor'' test result has been achieved, Euro NCAP 
may choose to comment on this alongside the normal pedestrian 
protection score. The results of these tests will not be reflected 
in the pedestrian protection score or any other part of the overall 
assessment.
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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.
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    \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
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[[Page 76954]]

vi. Testing Forward of WAD1000 for Small Vehicles
    Regarding smaller vehicles, the NPRM's regulatory text reflecting 
the GTR specifies that the forward border of the required test area 
would be the 82.5 mm offset line or WAD1000, whichever is most 
rearward. Under this proposed provision, requirements for head 
protection would start at WAD1000 for most small vehicles as the 
WAD1000 line is usually more rearward than the 82.5 mm offset line. 
However, for many smaller vehicles WAD1000 is far up the hood, which 
means much of the hood (the forward portion) would not be subject to 
any headform testing. It does not appear there are practicability 
barriers to headform testing of the hood on small vehicles, because 
comparable areas of the hood on larger vehicles would be regulated 
under the proposed standard and thus subject to headform testing. 
Testing forward of WAD1000 would potentially add to the protection of 
children with a standing height of less than 1,000 mm. As discussed 
below, to increase the safety benefits of the rule, we are considering 
an alternative provision that would test forward of WAD1000. NHTSA 
requests comment on this issue.
Request for Comment on Modifying the Forward Border
    Based on the above discussion, NHTSA requests comments on the 
questions below to help the agency decide whether a final rule should 
identify the forward border differently. Please comment on the 
potential gain in safety benefits as well as any potential 
practicability, cost, or technical issues.
     The NPRM's regulatory text reflects the GTR 9 provision 
that accounts for the situation where the tip of the 1,000 mm straight 
edge defines the LERL (rather than a point further down along the 
straight edge), such as when the tip of the straight edge could make 
first contact with the grille of a subject vehicle. In this situation, 
the WAD1000 line becomes the LERL. This means that the testable area 
could potentially include the grille area of the vehicle (i.e., 
headform impacts could be conducted on the grille area of the vehicle). 
We request comment on adjustments to the launch angle \109\ for such 
impacts, to potentially make them more perpendicular to the impacted 
surface to replicate a real-world impact more accurately. What impact 
point condition/location should trigger a change in impactor launch 
angle? Additionally, should the estimate of Hood Area be modified if 
some portion of the Hood Top is in the grille area, such as using a 
test area projection onto a vertical plane for the more vertical tests 
areas?
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    \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.
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     There may be large vehicles with a hood height slightly 
lower than those where the straight edge tip contacts the vehicle 
first, such that the provision to drop the LERL to WAD1000 is not 
triggered. Additionally, the NPRM's regulatory text (reflecting the 
GTR) specifies that, for large vehicles in general, the Child Headform 
Test Area begins well rearward of WAD1000--i.e., well rearward of where 
a child's head is likely to strike. However, NHTSA requests comments on 
changing the front border of the Child Headform Test Area to be either 
the Offset Line or WAD1000, whichever is forward-most, rather than 
rearmost. An outcome of this change would be that, in some cases, the 
test area would be forward of the Hood Top and conforming changes would 
need to be made to maintain the test area within the Hood Top. We note 
that the Euro NCAP and the NCAP RFC allow for testing at WAD1000, even 
if it is forward of the LERL. Euro NCAP monitors performance at the 
LERL as far forward as WAD930 if the LERL is forward of WAD1000, 
although this does not factor into the score.
     For many smaller vehicles the forward line where testing 
is required is at WAD1000, far behind the LERL, which means much of the 
hood (the forward portion) would not be subject to headform testing. We 
note that subjecting these forward areas of the hood to the standard 
may benefit children smaller than the average 6-year-old. A potential 
way to subject the forward areas to testing could be the same as that 
suggested above for larger vehicles, i.e., selection of the test area 
boundary based on the forward-most of the WAD1000 or of the Offset 
Line, rather than the rearward-most. We ask for comment on this issue 
in the context of smaller vehicles.
     As discussed above, another alternative on which we 
request comment involves how the GTR determines the HIC Unlimited 
Margin for the front and sides. (Impacts in the HIC Unlimited Margin 
are not subject to any HIC limit.) The NPRM's regulatory text reflects 
the GTR's specification that the margin would be determined using an 
82.5 (3.25 inch) mm taut wire, but NHTSA finds merit in using a 50 mm 
(1.97 inch) taut wire instead to increase the testable area, and reduce 
the allowable area of the HIC Unlimited Margin.
2. Transition Between Child and Adult Headform Test Areas at WAD1700
    Consistent with the GTR, proposed FMVSS No. 228 would separate the 
Child Headform Test Area from the Adult Headform Test Area at WAD1700. 
For many smaller vehicles, it is possible that there would be no Adult 
Headform Test Area at all when the transition between the child and 
adult test areas is drawn at WAD1700. Consistent with the GTR, proposed 
FMVSS No. 228 would require that, if there is only a Child Headform 
Test Area, the requirements that applied to the combined Child and 
Adult Headform Test Area are applied to the Child Headform Test Area 
alone. For example, at least two-thirds of the numerical value of the 
Hood Area, when placed within the boundary of the Child Headform Test 
Area (as opposed to the combined areas) must not exceed HIC of 1000 
using the child headform. For the remaining area the HIC shall not 
exceed 1700.

[[Page 76955]]

    This NPRM uses WAD1700 to transition between the Adult and Child 
Headform Test Areas because GTR data indicate that 6- to 15-year-old 
child head impacts start at about WAD1000 and end at WAD1700. A 5th 
percentile female has a standing height of an average 12-year-old child 
and would likely have a head impact within the Child Headform Test 
Area. Consistent with this, figure VI.17 below from the Pedestrian 
Crash Data Study (PCDS) shows that for all adults, impacts start at 
about WAD1400 and end at WAD2400. PCDS shows that about 70% of all 
adult pedestrian head impacts are between WAD1000 and WAD2100. 
Separating the genders, about half of adult female and one third of 
adult male head impacts are between WAD1000 and W1700 (not depicted in 
figure VI.17). As shown in figure VI.17, the WAD1700 represents the 
75th percentile for children under age 10 and the 25th percentile for 
all adults. Because stature distribution has remained stable over the 
past two decades \110\ and because WAD has been shown to depend 
primarily on the pedestrian's stature for a particular vehicle impact 
speed,111 112 113 this WAD distribution would still be 
representative today.
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    \110\ Fryar CD, Kruszon-Moran D, Gu Q, Ogden CL. Mean body 
weight, height, waist circumference, and body mass index among 
adults: United States, 1999-2000 through 2015-2016. National Health 
Statistics Reports; no 122. Hyattsville, MD: National Center for 
Health Statistics. 2018.
    \111\ Ivarsson J, et al. ``Pedestrian Head Impact--What 
Determines the Likelihood and Wrap Around Distance?'', 20th Enhanced 
Safety of Vehicles Conference (2007); paper no. 07-0373.
    \112\ Kiuchi T, et al. ``Comparative Study of VRU Head Impact 
Locations,'' Sixth Expert Symposium on Accident Research (ESAR). 
Hanover, Germany (2014).
    \113\ Otte, D. ``Wrap Around Distance WAD of Pedestrian and 
Bicyclists and Relevance as Influence Parameter for Head Injuries,'' 
SAE Technical Paper 2015-01-1461, 2015.
[GRAPHIC] [TIFF OMITTED] TP19SE24.023

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

[[Page 76956]]

likely to be engineered into the design of a hood, and that a step 
change approach reduces the need to conduct unnecessary headform tests. 
In practice, a sudden step change produces a hood design with an area 
around the transition line that is safe for both child and adult 
pedestrians. Therefore, it was decided that a hood designed for 
overlapping child-adult safety is effectively achieved without the need 
to specify the use of two headforms. Further, a defined boundary at 
1,700 mm provides a clearer approach. The GTR adopted the step change 
approach with a transition at WAD1700, which biases protection towards 
children. That is, the use of WAD1700 makes more of the hood tuned to 
protect a child's head than an adult head. Rather than having to design 
hoods for both head masses, the use of a non-overlapping transition at 
WAD1700 allows safety in the transition area to be optimized for the 
lighter headform.
Request for Comment on the Transition Zone
     NHTSA tentatively agrees with the above reasons and has 
drafted the regulatory text of proposed FMVSS No. 228 to specify a non-
overlapping transition from the Child Headform Test Area to the Adult 
Headform Test Area at WAD1700. However, we request comments on the 
merits of a transition zone. We would like to know more about the 
degree to which a step change approach addresses safety for both adults 
and children for vehicles that have sharp changes in structure, such as 
the joint between the rear of the hood and the cowl, which may occur 
along the transition line. This is indeed the case for many smaller 
vehicles which have no Adult Headform Test Area at all when the 
transition is drawn at WAD1700. While this helps with design 
feasibility for such vehicles (requirements apply for the lighter 
headform only), it may reduce the safety of such vehicles for shorter 
adult pedestrians because the hood may not provide sufficient 
penetration depth for the heavier adult headform. We therefore seek 
comment on other options for FMVSS No. 228. These options may include a 
revised procedure in which the adult/child border is drawn at a 
different WAD and use of a transition area that is tested with both 
headforms.
3. Rear Border of Adult Headform Test Area
    Consistent with GTR 9, the rear border of the Adult Headform Test 
Area is the HIC Unlimited Margin of the Rear Reference Line, which is 
the WAD2100 line or the 82.5mm offset line, whichever is more forward. 
WAD2100 is based on the average height of a 50th percentile adult male, 
which is about 1750 mm. This height is about the 97th percentile for 
adult females in the U.S.\114\
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    \114\ Based on 2007-2010 NHANES from https://tools.openlab.psu.edu/tools/explorer.php.
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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\
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    \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.
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    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\
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    \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.
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    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.
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    \117\ ECE/TRANS/WP.29/GRSP/2021/28.
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     Given the above, there appears to be merit to including 
the windshield in a test area for FMVSS No. 228. The regulatory text of 
this NPRM does not include the windshield, but NHTSA is considering 
language for a final rule that would include the windshield. The NCAP 
RFC and various international NCAP programs that assess pedestrian 
safety (Euro NCAP, Japan NCAP, Korea NCAP, and Australian NCAP) include 
a head-to-windshield impact test area. In addition, a UNECE Reg. No. 
127 proposal also includes the windshield for testing.
    2. The next subject for consideration is the limitation of testing 
beyond WAD2100. Consistent with GTR 9, this NPRM's regulatory text 
states that the rear border of the Adult Headform Test Area is either 
WAD2100 or the HIC Unlimited Margin of the Rear Reference Line, 
whichever is more forward. However, the ECE proposal mentioned above 
changes WAD2100 to WAD2500. That is, the rear border of the Adult 
Headform Test Area (``Adult Bonnet Top Headform Test Area'' in the ECE 
proposal) would be changed from the forwardmost of WAD2100 or the 82.5 
mm offset line, to the forwardmost of WAD2500 or the 82.5 mm offset 
line. The change to WAD2500 would increase the test area. We are also 
aware of similar changes to the Euro NCAP requirements being 
implemented in 2023, with the area between WAD2100 and WAD2500 being 
referred to as the Cyclist Zone.\118\ WAD2500 might extend past the 
windshield to the roof, and, under Euro NCAP procedures, the A-pillars 
are tested. Any impacts to the roof under Euro NCAP procedures involve 
a 45-degree angle rather than 65 degrees. We are considering similarly 
changing WAD2100 to WAD2500 for FMVSS No. 228.
---------------------------------------------------------------------------

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

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

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

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

[[Page 76958]]

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

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

VII. Proposed Requirements and Assessing Compliance

A. Amount of Hood Area That Must Conform to HIC1000

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

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

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

[[Page 76959]]

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

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

B. Manufacturer Designations of HIC1700 Areas

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

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

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

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

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

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

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

C. First Point of Contact

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

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

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

[[Page 76960]]

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

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

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

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

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

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

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

[[Page 76961]]

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

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

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

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

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

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

VIII. GTR 9 Terminology and Amendment 3

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

A. Comparison of Terminology

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

[[Page 76962]]



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

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

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

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

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


[[Page 76963]]

B. Amendment 3

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

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

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

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


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


[[Page 76964]]

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


    As explained above, in the 2D Method, the 2D measure point on the 
hood is established prior to a launch and the pre-test position of the 
headform is determined by aligning the mid-sagittal plane of the 
headform to that point. Although proponents of the 2D Method argued 
that this method of pre-determining the test point on the hood and 
assigning the test results to that point improves objectivity of the 
test, NHTSA disagrees. For the hood profile shown in figure VIII.1, the 
test results for a range of 2D measure points will be associated with 
the headform impacting the same hood location (the sharp transition). 
NHTSA believes this situation creates ambiguity rather than improves 
objectivity because in some instances, the HIC assignment for a point 
might not be related to the point being impacted. As illustrated in 
figure VIII.1, the HIC values were assigned to points on the slope, 
from an impact location further up the slope. In contrast, the 3D 
Method is more representative of real-world impacts as it assigns each 
test result to its corresponding location of impact (first contact 
point) (see figure VIII.2).
BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TP19SE24.026

BILLING CODE 4910-59-C
    Additionally, in the 3D Method both the lateral pre-test position 
of the headform as well as the first point of contact are known, which 
enables NHTSA to fully define each test in a compliance 
proceeding.\136\ This makes each test objective and highly repeatable. 
Thus, we see no reason to favor the 2D Method over the 3D Method based 
on claims of improved objectivity.
---------------------------------------------------------------------------

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

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

[[Page 76966]]

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

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

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

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

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[[Page 76967]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.027

BILLING CODE 4910-59-C

IX. Headform Characteristics

A. General

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

[[Page 76968]]

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

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

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

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

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

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

B. Qualification Limits

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

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

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

C. Repeatability and Reproducibility

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

[[Page 76969]]

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

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

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

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

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

[[Page 76970]]

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

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

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

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

[[Page 76971]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.028

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

[[Page 76972]]

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

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

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

    We analyzed HIC scores produced by child headforms fitted with 
Endevco model 7264G damped accelerometers. For the six pairs of tests 
considered, the variability was no greater than 7 percent in any of the 
paired tests. Also, there was no apparent trend in which one headform 
produced higher HIC scores than the other. For four of the test points, 
the lowest HIC score was produced by the FTSS unit. In the other two, 
the Cellbond scores were lowest. We did observe that the FTSS child 
unit had relatively high variability for HIC (Standard Deviation = 46), 
but not peak acceleration. Adult headforms had much lower variability 
for all conditions.
4. Instrumentation
Proposal for Damped Accelerometers
    This NPRM proposes a specification for damped accelerometers in the 
headforms. Although the GTR does not refer specifically to damped \150\ 
accelerometers, the preamble to the GTR recommends damped 
accelerometers based on findings from a 2002 research program using 
2001 headform data collected for the Japan New Car Assessment Program 
(J-NCAP). In headform tests with undamped accelerometers, abnormal 
signals that produced high HIC values were observed in windshield 
impacts \151\ and occasionally in hood impacts. The cause of the 
abnormality was attributed to vibrations that arose when the impulse of 
the impact was near the resonant frequency of the 
accelerometer.152 153
---------------------------------------------------------------------------

    \150\ In general, damped accelerometers are used when shock 
pulses of extremely short durations occur in a test environment that 
would otherwise induce resonance in the sensor.
    \151\ The windshield is no longer included within the test area 
prescribed by the GTR.
    \152\ Informal document no. GR/PS/96, Problem of undamped 
accelerometer in headform impact test. 7th meeting of the pedestrian 
safety informal working group, Paris, France, September 28, 2004.
    \153\ Informal document no. GR/PS/133, Miniature Damped 
Accelerometer Series, 8th meeting of the pedestrian safety informal 
working group, Brussels, July 11, 2005.
---------------------------------------------------------------------------

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

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

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

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

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

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

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

[[Page 76973]]

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

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

X. Other Issues

A. Active Hoods

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

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

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

[[Page 76974]]

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

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

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

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

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

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

XI. Effect on Other Standards

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

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

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

[[Page 76975]]

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

    \164\ The Motor Vehicle Information and Cost Savings Act, 49 
U.S.C. 325, provided for promulgation of bumper standards to reduce 
the economic loss resulting from damage to passenger motor vehicles 
involved in motor vehicle crashes.
---------------------------------------------------------------------------

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

[[Page 76976]]

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

XII. Proposed Lead Time

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

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

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

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

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

XIII. Benefits and Costs

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

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

[[Page 76977]]



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

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

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

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

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

XIV. Considered Alternatives

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

[[Page 76978]]

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

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

XV. Rulemaking Analyses and Notices

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

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

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

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

Regulatory Flexibility Act

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

[[Page 76979]]

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

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

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

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

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

[[Page 76980]]

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

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

[[Page 76981]]

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

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

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

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

National Environmental Policy Act

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

Executive Order 13132 (Federalism)

    NHTSA has examined this proposed rule pursuant to Executive Order 
13132 (64 FR 43255, August 10, 1999) and concluded that no additional 
consultation with States, local governments or their representatives is 
mandated beyond the rulemaking process. The agency has concluded that 
the rulemaking will not have sufficient federalism implications to 
warrant consultation with State and local officials or the preparation 
of a federalism summary impact statement. The proposed rule will not 
have ``substantial direct effects on the States, on the relationship 
between the national government and the States, or on the distribution 
of power and responsibilities among the various levels of government.''
    NHTSA rules can preempt in two ways. First, the National Traffic 
and Motor Vehicle Safety Act contains an express preemption provision: 
When a motor vehicle safety standard is in effect under this chapter, a 
State or a political subdivision of a State may prescribe or continue 
in effect a standard applicable to the same aspect of performance of a 
motor vehicle or motor vehicle equipment only if the standard is 
identical to the standard prescribed under this chapter. 49 U.S.C. 
30103(b)(1). It is this statutory command by Congress that preempts any 
non-identical State legislative and administrative law addressing the 
same aspect of performance.
    The express preemption provision described above is subject to a 
savings clause under which ``[c]ompliance with a motor vehicle safety 
standard prescribed under this chapter does not exempt a person from 
liability at common law.'' 49 U.S.C. 30103(e). Pursuant to this 
provision, State common law tort causes of action against motor vehicle 
manufacturers

[[Page 76982]]

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

Civil Justice Reform

    Section 3(b) of Executive Order 12988, ``Civil Justice Reform'' (61 
FR 4729, February 7, 1996) requires that, when promulgating a new 
regulation, Executive agencies make every reasonable effort to ensure 
that the regulation: (1) Clearly specifies any preemptive effect; (2) 
clearly specifies any effect on existing Federal law or regulation; (3) 
provides a clear legal standard for affected conduct, while promoting 
simplification and burden reduction; (4) clearly specifies the 
retroactive effect, if any; (5) adequately defines key terms, either 
explicitly or by reference to other regulations or statutes that 
explicitly define those items; and (6) addresses other important issues 
affecting clarity and general draftsmanship of regulations under any 
guidelines issued by the Attorney General. This document is consistent 
with that requirement.
    Pursuant to this Order, NHTSA notes as follows. The preemptive 
effect of this proposed rule is discussed above. NHTSA notes further 
that there is no requirement that individuals submit a petition for 
reconsideration or pursue other administrative proceeding before they 
may file suit in court.

Paperwork Reduction Act (PRA)

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

National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act (NTTAA) requires NHTSA to evaluate and use existing voluntary 
consensus standards in its regulatory activities unless doing so would 
be inconsistent with applicable law (e.g., the statutory provisions 
regarding NHTSA's vehicle safety authority) or otherwise impractical.
    Voluntary consensus standards are technical standards developed or 
adopted by voluntary consensus standards bodies. Technical standards 
are defined by the NTTAA as ``performance-based or design-specific 
technical specification and related management systems practices.'' 
They pertain to ``products and processes, such as size, strength, or 
technical performance of a product, process or material.'' Examples of 
organizations generally regarded as voluntary consensus standards 
bodies include the American Society for Testing and Materials (ASTM), 
the Society of Automotive Engineers (SAE), and the American National 
Standards Institute (ANSI). If NHTSA does not use available and 
potentially applicable voluntary consensus standards, we are required 
by the Act to provide Congress, through OMB, an explanation of the 
reasons for not using such standards.
    This proposal to adopt GTR 9 is consistent with the goals of the 
NTTAA. This NPRM proposes to adopt a global consensus standard. The GTR 
was developed by a global regulatory body and is designed to increase 
global harmonization of differing vehicle standards. The GTR leverages 
the expertise of governments in developing a vehicle standard to reduce 
the risk of pedestrian head injury in impacts. NHTSA's consideration of 
GTR 9 accords with the principles of NTTAA as NHTSA's consideration of 
an established, proven regulation has reduced the need for NHTSA to 
expend significant agency resources on the same safety need addressed 
by GTR 9. This NPRM explains the reasons the FMVSS under consideration 
differs in some respects from GTR 9, and why NHTSA is considering 
additional changes to GTR 9 for the final rule. NHTSA will consider the 
comments to the NPRM and other information in drafting a final rule. If 
differences remain between the final rule and the GTR, the agency will 
explain in the final rule NHTSA's reasons for deciding such differences 
are warranted, consistent with the NTTAA.

Unfunded Mandates Reform Act

    Section 202 of the Unfunded Mandates Reform Act of 1995 (UMRA), 
Public Law 104-4, requires Federal agencies to prepare a written 
assessment of the costs, benefits, and other effects of proposed or 
final rules that include a Federal mandate likely to result in the 
expenditure by State, local, or tribal governments, in the aggregate, 
or by the private sector, of more than $100 million (adjusted for 
inflation with base year of 1995) in any one year. Adjusting this 
amount by the implicit gross domestic product price deflator for the 
year 2021 results in $178 million (2021 index value of 270.97/1995 
index value of 152.40 = 1.78 \174\). This proposed rule would not 
result in a cost of $178 million or more in any one year to either 
State, local, or tribal governments, in the aggregate, or the private 
sector. Thus, this proposed rule is not subject to the requirements of 
sections 202 of the UMRA.
---------------------------------------------------------------------------

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

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

[[Page 76983]]

Incorporation by Reference

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

Severability

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

Regulation Identifier Number

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

Plain Language

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

XVI. Public Participation

How long do I have to submit comments?

    Please see DATES section at the beginning of this document.

How do I prepare and submit comments?

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

How can I be sure that my comments were received?

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

How do I submit confidential business information?

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

[[Page 76984]]

Will the Agency consider late comments?

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

How can I read the comments submitted by other people?

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

Potential Equity or Climate Change Impacts

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

Privacy Act

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

List of Subjects in 49 CFR Part 571

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

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

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

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

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

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


 Sec.  571.5  Matter incorporated by reference.

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


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

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

[[Page 76985]]

[GRAPHIC] [TIFF OMITTED] TP19SE24.030

Where:

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

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

[[Page 76986]]

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

[[Page 76987]]

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

[[Page 76988]]

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

[[Page 76989]]

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