[Federal Register Volume 88, Number 113 (Tuesday, June 13, 2023)]
[Proposed Rules]
[Pages 38632-38736]
[FR Doc No: 2023-11863]

Vol. 88

Tuesday,

No. 113

June 13, 2023

Part III

Department of Transportation

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National Highway Traffic Safety Administration

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49 CFR Parts 571 and 596

Federal Motor Vehicle Safety Standards: Automatic Emergency Braking
Systems for Light Vehicles; Proposed Rule

Federal Register / Vol. 88 , No. 113 / Tuesday, June 13, 2023 /
Proposed Rules

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 571 and 596

[Docket No. NHTSA-2023-0021]
RIN 2127-AM37

Federal Motor Vehicle Safety Standards: Automatic Emergency
Braking Systems for Light Vehicles

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

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This NPRM proposes to adopt a new Federal Motor Vehicle Safety
Standard to require automatic emergency braking (AEB), including
pedestrian AEB (PAEB), systems on light vehicles. 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. The
AEB system proposed in this NPRM would detect and react to an imminent
crash with a lead vehicle or pedestrian. This NPRM promotes NHTSA's
goal to equip vehicles with AEB and PAEB, and advances DOT's January
2022 National Roadway Safety Strategy that identified requiring AEB,
including PAEB technologies, on new passenger vehicles as a key
Departmental action to enable safer vehicles. This NPRM also responds
to a mandate under the Bipartisan Infrastructure Law directing the
Department to promulgate a rule to require that all passenger vehicles
be equipped with an AEB system.

DATES: Comments must be received on or before August 14, 2023.
    Proposed compliance date: Vehicles manufactured on or after
September 1, four years after the publication date of a final rule,
would be required to meet all requirements. Vehicles manufactured on or
after September 1, three years after the publication date of a final
rule, but before September 1, four years after the publication date of
a final rule, would be required to meet all requirements except that
lower speed PAEB performance test requirements specified in S5(b) would
apply. Small-volume manufacturers, final-stage manufacturers, and
alterers would be provided an additional year (added to those above) to
meet the requirements of the final rule. Early compliance is permitted
but optional.

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<PHONE_NUMBER> before
coming.
     Fax:<PHONE_NUMBER>.
    Regardless of how you submit your comments, please provide 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.
    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. In order 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.
    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-
366-9332 before coming. Follow the online instructions for accessing
the dockets.

FOR FURTHER INFORMATION CONTACT: For non-legal issues: Markus Price,
Office of Crash Avoidance Standards (telephone:<PHONE_NUMBER>). For
legal issues: David Jasinski, Office of the Chief Counsel (telephone:
202-366-2992, fax:<PHONE_NUMBER>). 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
II. Safety Problem
    A. Overall Rear-End Crash Problem
    B. Rear-End Crashes by Vehicle Type
    C. Rear-End Crashes by Posted Speed Limit
    D. Rear-End Crashes by Light Condition
    E. Rear-End Crashes by Atmospheric Conditions
    F. Pedestrian Fatalities and Injuries
    G. Pedestrian Fatalities and Injuries by Initial Point of Impact
and Vehicle Type
    H. Pedestrian Fatalities and Injuries by Posted Speed Limit
Involving Light Vehicles
    I. Pedestrian Fatalities and Injuries by Lighting Condition
Involving Light Vehicles
    J. Pedestrian Fatalities and Injuries by Age Involving Light
Vehicles
    K. AEB Target Population
III. Data on Effectiveness of AEB in Mitigating Harm
IV. NHTSA's Earlier Efforts Related to AEB
    A. NHTSA's Foundational AEB Research
    1. Forward Collision Warning Research
    2. AEB Research To Prevent Rear-End Impacts With a Lead Vehicle
    3. AEB Research To Prevent Vehicle Impacts With Pedestrians
    4. Bicycle and Motorcycle AEB
    B. NHTSA's New Car Assessment Program
    1. FCW Tests
    2. Lead Vehicle AEB Tests
    3. PAEB Test Proposal
    C. 2016 Voluntary Commitment
    D. Response To Petition for Rulemaking
V. NHTSA's Decision to Require AEB
    A. This Proposed Rule Is Needed To Address Urgent Safety
Problems
    B. Stakeholder Interest in AEB
    1. National Transportation Safety Board Recommendations
    2. Consumer Information Programs in the United States
    3. Petition for Rulemaking on PAEB Performance in Dark
Conditions
    C. Key Findings Underlying This Proposal
    1. Impact Speed Is Key to Improving AEB's Mitigation of
Fatalities and Injuries
    2. Darkness Performance of PAEB Is Highly Important
    3. NHTSA's 2020 Research on Lead Vehicle AEB and PAEB
Performance Show the Practicability of Higher Speed Tests
    a. Lead Vehicle AEB Performance Tests
    b. PAEB Daytime Performance Tests
    c. PAEB Darkness Performance Tests
    d. PAEB Darkness Performance Tests With Overhead Lighting
    4. This Proposed Standard Complements Other NHTSA Actions
VI. Proposal To Require Automatic Emergency Braking

    A. Lead Vehicle AEB System Requirement
    B. Forward Collision Warning Requirement
    1. FCW Modalities
    2. FCW Auditory Signal Characteristics
    3. FCW Visual Signal Characteristics
    4. FCW Haptic Signal
    C. Lead Vehicle AEB--Performance Test Requirements
    1. Stopped Lead Vehicle Scenario Test Speeds
    2. Slower-Moving Lead Vehicle Scenario Test Speeds
    3. Decelerating Lead Vehicle Scenario Test Speeds
    4. Subject Vehicle Brake Application
    D. PAEB System Requirement
    E. PAEB--FCW Requirement
    F. PAEB--Performance Test Requirements
    1. PAEB Scenario Descriptions
    2. Overlap
    3. Vehicle and Pedestrian Surrogate Travel Speeds
    4. Crossing Path Scenario Testing Speeds
    5. Stationary Scenario Testing Speeds
    6. Along Path Scenario Testing Speeds
    7. PAEB Darkness Testing
    G. Alternatives to No-Contact Performance Test Requirement
    H. False Activation Requirement
    1. Steel Trench Plate False Activation Scenario
    2. Pass-Through False Activation Scenario
    3. Potential Alternatives to False Activation Requirements
    I. Malfunction Detection Requirement
    J. AEB System Disablement
    K. AEB System Performance Information
VII. AEB Test Procedures
    A. AEB System Initialization
    B. Travel Path
    C. Subject Vehicle Preparation
    D. Subject Vehicle Tolerance Specifications
    E. Lead Vehicle Test Set Up and Tolerance
    F. Test Completion Criteria for Lead Vehicle AEB Tests
    G. PAEB Test Procedures and Tolerance
    H. False Positive AEB Test Procedures
    I. Environmental Test Conditions
    J. Test Track Conditions
    K. Subject Vehicle Conditions
VIII. Test Devices
    A. Pedestrian Test Mannequins
    1. Background
    2. Mannequin Appearance
    3. Color and Reflectivity
    4. Radar Cross Section
    5. Other Considerations
    B. Vehicle Test Device
    1. Description and Development
    2. Specifications
    3. Alternatives Considered
IX. Proposed Effective Date Schedule
X. Summary of Estimated Effectiveness, Cost, and Benefits
    A. Target Population
    B. Lead Vehicle AEB System Effectiveness
    C. PAEB System Effectiveness
    D. Fatalities Avoided and Injuries Mitigated
    E. Costs
    F. Cost-Effectiveness
    G. Comparison of Regulatory Alternatives
XI. Regulatory Notices and Analyses
XII. Public Participation
XIII. Appendices to the Preamble

I. Executive Summary

    In 2019, there were 6,272 pedestrian fatalities in motor vehicle
crashes, representing 17 percent of all motor vehicle fatalities.\1\
This represents the continuation of the recent trend of increased
pedestrian deaths on our nation's roadways.\2\ A further 76,000
pedestrians were injured in motor vehicle crashes. In addition, there
were nearly 2.2 million rear-end police-reported crashes involving
light vehicles, which led to 1,798 deaths and 574,000 injuries. Deaths
and injuries in more recent years are even greater. However, the
agency's analysis of the safety problem focuses on the calendar year
2019 because it is the most recent year without the prominent effect of
the COVID-19 pandemic.
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    \1\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813079 Pedestrian Traffic Facts 2019 Data, May 2021.
    \2\ Id., Table 1 Pedestrian fatalities 2010--4,302, 2019--6,272.
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    This NPRM proposes to address this significant safety problem by
proposing a new Federal Motor Vehicle Safety Standard (FMVSS) to
require automatic emergency braking (AEB) systems on light vehicles
that are capable of reducing the frequency and severity of both rear-
end and pedestrian crashes. This proposed action represents a crucial
step forward in implementing DOT's January 2022 National Roadway Safety
Strategy (NRSS) to address the rising numbers of transportation deaths
and serious injuries occurring on this country's streets, roads, and
highways, including actions to protect vulnerable road users, including
pedestrians.\3\
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    \3\ https://www.transportation.gov/sites/dot.gov/files/2022-01/USDOT_National_Roadway_Safety_Strategy_0.pdf.
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    The Department's Safe System Approach emphasizes that multiple,
complementary safety interventions to prevent crashes are critical to
improving safety and protecting people. Through the NRSS, the
Department is focusing on advancing initiatives that will significantly
enhance roadway safety. These initiatives include infrastructure design
and interventions along with proposed vehicle regulations such as this
one. The Department is advancing support for the implementation of
Complete Streets policies to help transportation agencies across the
United States plan, develop, and operate roads, streets, and networks.
Complete Streets policies prioritize safety, comfort, and connectivity
to destinations for all users, including pedestrians, bicyclists, those
who use wheelchairs and mobility devices, transit riders, micro-
mobility users, shared ride services, motorists, and freight delivery
services. NHTSA is providing technical assistance to States to
encourage the adoption of a safe system approach with emphasis on
partnering with State Departments of Transportation and Emergency
Medical Service agencies to comprehensively address various roadway
issues including those affecting those who walk, bike and roll. NHTSA
awards annual formula grants to the States to conduct lifesaving
highway safety programs and is also assisting States as they conduct
meaningful public engagement to ensure that affected communities are
involved in program planning and implementation.
    The crash problem that can be addressed by AEB is substantial.\4\
For example, 60 percent of fatal rear-end crashes and 73 percent of
injury crashes were on roads with posted speed limits of 60 mph or
below. Similarly, most of these crashes occurred in clear, no adverse
atmospheric conditions--72 percent of fatal crashes and 74 percent of
injury crashes. Also, about 51 percent of fatal and 74 percent of rear-
end crashes involving light vehicles resulting in injuries occurred in
daylight conditions. In addition, 65 percent of pedestrian fatalities
and 67 percent of pedestrian injuries were the result of a strike by
the front of a light vehicle. Of those, 77 percent, and about half of
the pedestrian injuries, occur in dark lighting conditions. This NPRM
proposes to adopt a new FMVSS to require AEB systems on light vehicles
that are capable of reducing the frequency and severity of both lead
vehicle and pedestrian collisions.\5\ AEB systems employ sensor
technologies and sub-systems that work together to sense when the
vehicle is in a crash imminent situation, to automatically apply the
vehicle brakes if the driver has not done so, and to apply more braking
force to supplement the driver's braking. Current systems primarily use
radar- and camera-based sensors, while there are also emerging systems
that use lidar and thermal sensors. These systems can reduce both lead
vehicle rear-end (lead vehicle AEB) and pedestrian crashes (PAEB).
Importantly, this proposal would require that systems are able to avoid
pedestrian crashes in darkness testing conditions. AEB systems have

reached a level of maturity such that they will be able to reduce the
frequency and severity of crashes and are thus ready to be mandated on
all new light vehicles.
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    \4\ The Insurance Institute for Highway Safety (IIHS) estimates
a 50 percent reduction in front-to-rear crashes of vehicles with AEB
(IIHS, 2020) and a 25 to 27 percent reduction in pedestrian crashes
for PAEB (IIHS, 2022).
    \5\ For the purpose of this NPRM, ``light vehicles'' means
passenger cars, multipurpose passenger vehicles (MPVs), trucks, and
buses with a gross vehicle weight rating of 4,536 kilograms (10,000
pounds) or less.
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    This proposal is issued under the authority of the National Traffic
and Motor Vehicle Safety Act of 1966. Under 49 U.S.C. Chapter 301, the
Secretary of Transportation is responsible for prescribing motor
vehicle safety standards that are practicable, meet the need for motor
vehicle safety, and are stated in objective terms. The responsibility
for promulgation of FMVSSs is delegated to NHTSA. This rulemaking
addresses a statutory mandate under the Bipartisan Infrastructure Law
(BIL), codified as the Infrastructure Investment and Jobs Act
(IIJA),\6\ which added 49 U.S.C. 30129, directing the Secretary of
Transportation to promulgate a rule requiring that all passenger motor
vehicles for sale in the United States be equipped with a FCW system
and an AEB system.
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    \6\ Public Law 117-58, 24208 (Nov. 15, 2021).
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    The decision to mandate AEB builds on decades of research and
development, which began in the 1990s, with initial research programs
to support development of AEB technologies and methods by which system
performance could be assessed. NHTSA began testing AEB systems as part
of New Car Assessment Program (NCAP) in 2010 and reporting on the
respective research and progress surrounding the technologies shortly
thereafter.\7\ These research efforts led to the incorporation of AEB
into incentive programs designed to raise consumer awareness of AEB,
such as NCAP. NHTSA included FCW systems as a ``recommended advanced
technology'' in NCAP in model year 2011, and in November 2015, added
crash imminent braking (CIB) and dynamic brake support (DBS)
technologies to the program with assessments of these technologies to
begin in model year 2018.\8\ Most recently, NHTSA proposed upgrades to
the lead vehicle AEB test in its March 2022 request for comment on
NCAP.\9\ Separate from NCAP, in March 2016, NHTSA and Insurance
Institute for Highway Safety (IIHS) announced a commitment by 20
manufacturers representing more than 99 percent of the U.S. light
vehicle market to equip low-speed AEB as a standard feature on nearly
all new light vehicles not later than September 1, 2022. As part of
this voluntary commitment, manufacturers would include both FCW and a
CIB system that would reduce a vehicle's speed in certain rear-end
crash-imminent test conditions.
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    \7\ 77 FR 39561 (Jul. 2, 2012).
    \8\ 80 FR 68604 (Nov. 5, 2015).
    \9\ 87 FR 13452 (Mar. 9, 2022). See www.regulatinos.gov, docket
number NHTSA-2021-0002.
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    NHTSA also conducted research to understand the capabilities of
PAEB systems beginning in 2011. This work began with an assessment of
the most common pedestrian crash scenarios to determine how test
procedures could be designed to address them. As part of this
development, NHTSA also looked closely at a potential pedestrian
mannequin to be used during testing and explored several aspects of the
mannequin, including size and articulation of the arms and legs. This
work resulted in a November 2019 draft research test procedure
providing the methods and specifications for collecting performance
data on PAEB systems for light vehicles.\10\ This procedure was
expanded to cover updated vehicle speed ranges and different ambient
conditions and included in a March 2022 request for comments notice
proposing to include PAEB, higher speed AEB, blind spot warning and
blind spot intervention into NCAP.\11\
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    \10\ 84 FR 64405 (Nov. 21, 2019).
    \11\ 87 FR 13452 (Mar. 9, 2022).
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    While these actions have increased market penetration of AEB
systems, reduced injuries, and saved lives, NHTSA believes that
mandating AEB systems that can address both lead vehicle and pedestrian
crashes is necessary to better address the safety need. NHTSA
incorporated FCW into NCAP beginning in model year 2011 and AEB into
NCAP beginning in model year 2018. This has achieved success, with
approximately 65% of new vehicles meeting the lead vehicle test
procedures included in NCAP.\12\ Similarly, the voluntary commitment
resulted in approximately 90 percent of new light vehicles having an
AEB system.
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    \12\ Percentage based on the vehicle manufacturer's model year
2022 projected sales volume reported through the New Car Assessment
Program's annual vehicle information request.
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    However, the test speeds and performance specifications in NCAP and
the voluntary commitment would not ensure that the systems perform in a
way that will prevent or mitigate crashes resulting in serious injuries
and fatalities. The vast majority of fatalities, injuries, and property
damage crashes occur at speeds above 40 km/h (25 mph), which are above
those covered by the voluntary commitment.
    NCAP and, even more so, other voluntary measures are intended to
supplement rather than substitute for the FMVSS, which remain NHTSA's
core way of ensuring that all motor vehicles are able to achieve an
adequate level of safety performance. Thus, though the NCAP program
provides valuable safety-related information to consumers in a simple
to understand way, the agency believes that gaps in market penetration
will continue to exist for the most highly effective AEB systems. NHTSA
has also observed that, in the case of both electronic stability
control and rear visibility, 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 and concludes that only regulation can ensure that all
vehicles are equipped with AEB that meet the proposed performance
requirements.
    These considerations are of even greater weight when considering
whether to require a system that can reduce pedestrian crashes.
Pedestrian fatalities are increasing, and NHTSA's testing has
established that PAEB systems will be able to significantly reduce
these deaths.\13\ Manufacturers' responses to adding lead vehicle AEB
and other technologies into NCAP suggests that it would take several
years after PAEB is introduced into NCAP before the market began to see
significant numbers of new vehicles that would be able to meet a
finalized NCAP test. Moreover, as pedestrian safety addresses the
safety of someone other than the vehicle occupant, it is not clear if
past experiences with NCAP are necessarily indicative of how quickly
PAEB systems would reach the levels of lead vehicle AEB, if pedestrian
functionality that would meet NCAP performance levels was offered as a
separate cost to consumers. NHTSA believes that there can be a
significant safety benefit in NCAP providing consumers with information
about new safety technologies before it is prepared to mandate them,
but this is not a requirement.
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    \13\ The accompanying PRIA estimates the impacts of the rule.
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    A final factor weighing in favor of requiring AEB is that the
technology is a significantly more mature level than what it was at the
time of the voluntary commitment or when it was introduced into NCAP.
NHTSA's most recent testing has shown that higher performance levels
than those in the voluntary commitment or the existing NCAP
requirements are now practicable. Many model year 2019 and 2020
vehicles were able to repeatedly avoid impacting the lead vehicle in
CIB

tests and the pedestrian test mannequin in PAEB tests, even at higher
test speeds than those prescribed currently in the agency's CIB and
PAEB test procedures.
    These results show that AEB systems are capable of reducing the
frequency and severity of both lead vehicle and pedestrian crashes.
Mandating AEB systems would address a clear and, in the case of
pedestrian deaths, growing safety problem. To wait for market-driven
adoption, even to the extent spurred on by NCAP, would lead to deaths
and injuries that could be avoided if the technology were required, and
would be unlikely to result in all vehicles having improved AEB. Thus,
in consideration of the safety problem and NHTSA's recent test results,
and consistent with the Safety Act and BIL, NHTSA has tentatively
concluded that a new Federal motor vehicle safety standard requiring
AEB systems that can address both lead vehicle and pedestrian
collisions on all new light vehicles is necessary to address the
problem of rear-end crashes resulting in property damage, injuries, and
fatalities. The proposed lead vehicle AEB test procedures build on the
existing FCW, CIB, and DBS NCAP procedures, but include higher speed
performance requirements. Collision avoidance is required at speeds up
to 100 km/h (62 mph) when manual braking is applied and up to 80 km/h
(50 mph) when no manual braking is applied during the test. Based on
data from the 2019 and 2020 research programs, NHTSA believes that it
is practicable to require this higher level of system performance.
Performance at these speeds would address the injuries and fatalities
resulting from rear-end crashes. As part of this proposal, NHTSA is
including testing under both daylight and darkness lighting conditions.
In the darkness testing condition, NHTSA is proposing testing with both
lower beam and upper beam headlamps activated. NHTSA believes darkness
testing of PAEB is necessary because more than three-fourths of all
pedestrian fatalities occur in conditions other than daylight.
    The proposed standard includes four requirements for AEB systems
for both lead vehicles and pedestrians. First, vehicles would be
required to have an AEB system that provides the driver with a FCW at
any forward speed greater than 10 km/h (6.2 mph). NHTSA is proposing
that the FCW be presented via auditory and visual modalities when a
collision with a lead vehicle or a pedestrian is imminent. Based on
NHTSA's research, this proposal includes specifications for the
auditory and visual warning components. Additional warning modes, such
as haptic, would be allowed.
    Second, vehicles would be required to have an AEB system that
applies the brakes automatically at any forward speed greater than 10
km/h (6.2 mph) when a collision with a lead vehicle or a pedestrian is
imminent. This requirement would serve to ensure that AEB systems
operate at all speeds above 10 km/h (6.2 mph), even if these speeds are
above the speeds tested by NHTSA and provide at least some level of AEB
system performance in those rear-end crashes. An AEB system active at
any speed above 10 km/h (6.2 mph) will be able to mitigate collisions
at high speeds through, at a minimum, speed reduction.
    Third, the AEB system would be required to prevent the vehicle from
colliding with the lead vehicle or pedestrian test mannequin when
tested according to the proposed standard's test procedures. These
track test procedures have defined parameters that will ensure that AEB
systems prevent crashes in a controlled testing environment. There are
three general test scenarios each for testing vehicles with a lead
vehicle and four scenarios for testing vehicles with a pedestrian test
mannequin. These test scenarios are designed to ensure that AEB systems
are able to perform appropriately in common crash scenarios. In
particular, the agency has proposed that pedestrian tests be done in
both daylight and darkness. The proposed requirements also include two
false positive tests (driving over a steel trench plate and driving
between two parked vehicles) in which the vehicle would not be
permitted to brake in excess of 0.25g in addition to any manual brake
application.
    The final proposed requirement is that a vehicle must detect AEB
system malfunctions and notify the driver of any malfunction that
causes the AEB system not to meet the minimum proposed performance
requirements. Malfunctions would include those attributable to sensor
obstruction or saturation, such as accumulated snow or debris, dense
fog, or sunlight glare. The proposal only includes a specification that
the notification be visual.
    To ensure test repeatability that reflects how a subject vehicle--
that is the vehicle under test, would respond in the real world, this
proposal includes specifications for the test devices that NHTSA would
use in both the lead vehicle and pedestrian compliance tests, relying
in large part on relevant International Organization for
Standardization standards.
    This proposal would require that all of the AEB requirements be
phased in within four years of publication of a final rule. All
vehicles would be required to meet all requirements associated with
lead vehicle AEB and all daylight test requirements for PAEB within
three years. With respect to darkness testing, there are lower maximum
test speed thresholds that would have to be met within three years for
some specified test procedures. All vehicles would have to meet the
minimum performance requirements with higher darkness test speeds four
years after the publication of a final rule. Small-volume
manufacturers, final-stage manufacturers, and alterers would be
provided an additional year of lead time for all requirements.
    NHTSA has issued a Preliminary Regulatory Impact Analysis (PRIA)
that analyzes the potential impacts of this proposed rule. The PRIA is
available in the docket for this NPRM. The proposed rule is expected to
substantially decrease the safety problems associated with rear-end and
pedestrian crashes.
    NHTSA's assessment of available safety data indicates that between
2016 and 2019, there were an average of 1.12 million rear-impact
crashes involving light vehicles annually. These crashes resulted in an
approximate annual average of 394 fatalities, 142,611 non-fatal
injuries, and an additional 1.69 million damaged vehicles.
Additionally, between 2016 and 2019, there were an average of
approximately 23,000 crashes that could potentially be addressed by
PAEB annually. These crashes resulted in an annual average of 2,642
fatalities and 17,689 non-fatal injuries.
    AEB systems meeting the requirements of this proposed rule would
have a dramatic impact on risks associated with rear-end and pedestrian
crashes, even beyond the benefits assumed to occur due to NCAP and
other voluntary industry adoption. In order to determine the benefits
and costs of this rulemaking, NHTSA developed a baseline, which
reflects how the world would look in the absence of regulation. This
baseline includes an assumption that all new light vehicles will have
some AEB system and that approximately 65 percent of these vehicles
will have systems meeting the NCAP test procedures. Thus, the impacts
of this rule are less than the impacts of AEB as a technology, as it
only accounts for marginal improvements over the baseline. Accordingly,
NHTSA projects that this proposed rule would reduce fatalities by 362
(124 rear-end and 238 pedestrian) annually and reduce injuries by
24,321 (21,649 rear-end and 2,672

pedestrian) annually.\14\ In addition, lead vehicle AEB systems would
likely yield substantial benefits over the lifetime of the vehicle in
property damage avoided. Further, when calculating benefits, the agency
excluded many scenarios where AEB systems are still likely to lead to
safety benefits but where the agency has not conducted sufficient
research to quantify those benefits, including crashes involving
impacts into the rear of heavy vehicles. Further, the agency excluded
calendar years 2020 and 2021 from its analysis of the safety problem,
as those years may be atypical, but did include a sensitivity case in
the RIA, which shows greater benefits.
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    \14\ A breakdown of the severity of the injuries that would be
reduced by this proposed rule can be found in Section 4.3 of the
accompanying PRIA.
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    With regard to costs NHTSA anticipates that systems can achieve the
proposed requirements through upgraded software, as all vehicles are
assumed to have the necessary hardware. Therefore, the incremental cost
associated with this proposed rule reflects the cost of a software
upgrade that will allow current systems to achieve lead vehicle AEB and
PAEB functionality that meets the requirements specified in this
proposed rule. The incremental cost per vehicle is estimated at $82.15
for each design cycle change of the model.\15\ When accounting for
design cycles and annual sales of new light vehicles, the total annual
cost associated with this proposed rule is approximately $282.16
million in 2020 dollars.
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    \15\ The agency includes a higher potential cost value in the
RIA for ``disruptive'' software changes, which could also serve as a
proxy for potential additional costs, including hardware costs.
However, as discussed in the RIA, that value represents a less-
likely higher end assumption, while the value used here represents
the agency's main assumption. Importantly, though, even under the
higher assumption, benefits still greatly exceed costs.
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    Table 1 summarizes the finding of the benefit-cost analysis. The
projected benefits of this proposed rule greatly exceed the projected
costs. The lifetime monetized net benefit of this proposed rule is
projected to be between $5.24 and $6.52 billion with a cost per
equivalent life saved of between $500,000 and $620,000, which is far
below the Department's existing value of a statistical life saved,
which is currently calculated as $11.8 million.

 Table 1--Lifetime Summary of Benefits and Costs for Passenger Cars and
              Light Trucks (Millions 2020$), Discount Rate
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                                   3% Discount rate    7% Discount rate
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                                Benefits
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Lifetime Monetized..............              $6,802              $5,518
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                                  Costs
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Lifetime Monetized..............              282.16              282.16
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                              Net Benefits
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Lifetime Monetized..............               6,520               5,235
------------------------------------------------------------------------

                Table 2--Estimated Quantifiable Benefits
------------------------------------------------------------------------

------------------------------------------------------------------------
                                Benefits
------------------------------------------------------------------------
Fatalities Reduced.........................................          362
Injuries Reduced...........................................       24,321
------------------------------------------------------------------------

                  Table 3--Estimated Installation Costs
------------------------------------------------------------------------

------------------------------------------------------------------------
                              Costs (2020$)
------------------------------------------------------------------------
System installation per vehicle per       $82.15
 design cycle.
Total Fleet per year....................  282.16 M
------------------------------------------------------------------------

                  Table 4--Estimated Cost Effectiveness
------------------------------------------------------------------------

------------------------------------------------------------------------
                     Cost per Equivalent Life Saved
------------------------------------------------------------------------
AEB Systems......................  $0.50 to $0.62 million *
------------------------------------------------------------------------
* The range presented is from a 3% to 7% discount rate.

    NHTSA seeks comments and suggestions on all aspects of this
proposal and any alternative requirements that would address this
safety problem. NHTSA also requests comments on the proposed lead time
for meeting these requirements, and how the lead time can be structured
to maximize the benefits that can be realized most quickly while
ensuring that the standard is practicable.

Summary of Technical Terms

    The following is a brief explanation of terms and technologies used
to describe AEB systems. More detailed information can be found in
Appendix A to this preamble.
Radar-Based Sensors
    Many AEB systems employ radar sensors. At its simplest, radar is a
time-of-flight sensor technology that measures the time between when a
radio wave is transmitted and when its reflection is received back at
the radar sensor. This time-of-flight sensor input is used to calculate
the distance between the sensor and the object that caused the
reflection. Multiple or continuous sampling can also provide
information about the reflecting object, such as the speed at which it
is travelling.
Camera Sensors
    Cameras are passive sensors in which optical data are recorded and
then processed to allow for object detection and classification.
Cameras are an important part of many automotive AEB systems and are
typically mounted behind the front windshield near the rearview mirror,
sometimes in groups of two or more. Cameras at this location provide a
good view of the road and are protected by the windshield from debris,
grease, dirt, and other contaminants that could obstruct the sensor.
Some systems that use two or more cameras can see stereoscopically,
allowing the processing system to better determine range information
along with detection and classification.
Forward Collision Warning
    A forward collision warning (FCW) system uses sensors that detect
objects in front of vehicles and provides an alert to the driver. An
FCW system is able to use the sensors' input to determine the speed of
an object in front of it and the

distance between the vehicle and the object. If the FCW system
determines that the closing distance and velocity between the vehicle
and the object is such that a collision may be imminent, the system is
designed to induce an immediate forward crash avoidance response by the
vehicle operator. FCW systems may detect impending collisions with any
number of roadway obstacles, including vehicles and pedestrians.
Warning systems in use today provide drivers with a visual display,
such as an illuminated telltale on or near the instrument panel, an
auditory signal, or a haptic signal that provides tactile feedback to
the driver to warn the driver of an impending collision so the driver
may intervene. FCW systems alone do not brake the vehicle.
Electronically Modulated Braking Systems
    Automatic actuation of a vehicle's brakes requires more than just
technology to sense when a collision is imminent. In addition to the
sensing system, hardware is needed to apply the brakes without relying
on the driver to depress the brake pedal. The automatic braking system
relies on two foundational braking technologies--electronic stability
control to automatically activate the vehicle brakes and an antilock
braking system to mitigate wheel lockup. Not only do electronic
stability control and antilock braking systems enable AEB operation,
these systems also modulate the braking force so that the vehicle
remains stable while braking during critical driving situations where a
crash with a vehicle or pedestrian is imminent.
AEB Perception and Decision System
    The performance of each AEB system depends on the ability of the
system to use sensor data to appropriately detect and classify forward
objects. The AEB system uses this detection and classification to
decide if a collision is imminent and then avoid or mitigate the
potential crash. Manufacturers and suppliers of AEB systems have worked
to address unnecessary AEB activations through techniques such as
sensor fusion, which combines and filters information from multiple
sensors, and advanced predictive models.
Lead Vehicle Automatic Emergency Braking
    A lead vehicle AEB system automatically applies the brakes to help
drivers avoid or mitigate the severity of rear-end crashes. Lead
vehicle AEB has two similar functions that NHTSA has referred to as
crash imminent braking and dynamic brake support. Crash imminent
braking (CIB) systems apply automatic braking when forward-looking
sensors indicate a crash is imminent and the driver has not applied the
brakes. Dynamic brake support (DBS) systems use the same sensors to
supplement the driver's application of the brake pedal with additional
braking when sensors determine the driver has applied the brakes, but
the brake application is insufficient to avoid an imminent crash.
    This NPRM does not split the terminology of these CIB and DBS
functionalities, but instead considers them both as parts of AEB. When
NHTSA first tested implementation of these systems, NHTSA found that
DBS systems operated with greater automatic braking application than
CIB systems. However, more recent testing has shown that vehicle
manufacturers' CIB systems provide the same level of braking as DBS
systems. Nevertheless, the proposed standard includes performance tests
that would require an AEB system that has both CIB and DBS
functionalities.
Pedestrian Automatic Emergency Braking
    PAEB systems function like lead vehicle AEB systems but detect
pedestrians in front of the vehicle. PAEB systems intervene in crash
imminent situations in which the pedestrian is either directly in the
path of a vehicle or entering the path of the vehicle. Current PAEB
systems operate primarily when the vehicle is moving in a straight
line. Sensor performance is defined by sensing depth, field of view,
and resolution. However, performance may be degraded during low light
conditions. This NPRM proposes requiring PAEB system performance in
darkness conditions using the vehicle's headlamps for illumination.
``AEB'' as Used in This NPRM
    When this NPRM refers to ``AEB'' generally, unless the context
clearly indicates otherwise, it refers to a system that has: (a) an FCW
component to alert the driver to an impending collision with a forward
obstacle; (b) a CIB component that automatically applies the vehicle's
brakes if the driver does not respond to the FCW; and (c) a DBS
component that automatically supplements the driver's brake application
if the driver applies insufficient manual braking to avoid a crash.
Furthermore, unless the context indicates otherwise, reference to AEB
includes both lead vehicle AEB and PAEB.
Abbreviations Frequently Used in This Document
    The following table is provided for the convenience of readers for
illustration purposes only.

                                             Table 5--Abbreviations
----------------------------------------------------------------------------------------------------------------
              Abbreviation                         Full term                             Notes
----------------------------------------------------------------------------------------------------------------
AEB.....................................  Automatic Emergency Braking  Applies a vehicle's brakes automatically
                                                                        to avoid or mitigate an impending
                                                                        forward crash.
ADAS....................................  Advanced driver assistance
                                           system.
CIB.....................................  Crash Imminent Braking.....  Applies automatic braking when forward-
                                                                        looking sensors indicate a crash is
                                                                        imminent and the driver has not applied
                                                                        the brakes.
CRSS....................................  Crash Report Sampling        A sample of police-reported crashes
                                           System.                      involving all types of motor vehicles,
                                                                        pedestrians, and cyclists, ranging from
                                                                        property-damage-only crashes to those
                                                                        that result in fatalities.
DBS.....................................  Dynamic Brake Support......  Supplements the driver's application of
                                                                        the brake pedal with additional braking
                                                                        when sensors determine the driver-
                                                                        applied braking is insufficient to avoid
                                                                        an imminent crash.
FARS....................................  Fatality Analysis Reporting  A nationwide census providing annual data
                                           System.                      regarding fatal injuries suffered in
                                                                        motor vehicle crashes.
FCW.....................................  Forward Collision Warning..  An auditory and visual warning provided
                                                                        to the vehicle operator that is designed
                                                                        to induce an immediate forward crash
                                                                        avoidance response by the vehicle
                                                                        operator.
FMVSS...................................  Federal Motor Vehicle
                                           Safety Standard.

IIHS....................................  Insurance Institute for
                                           Highway Safety.
IIJA....................................  Infrastructure Investment    Public Law 117-58 (Nov. 15, 2021).
                                           and Jobs Act.
ISO.....................................  International Organization
                                           for Standardization.
Lead Vehicle AEB........................  Lead Vehicle Automatic       An AEB system that is capable of avoiding
                                           Emergency Braking.           or mitigating collisions with a lead
                                                                        vehicle.
MAIS....................................  Maximum Abbreviated Injury   A means of describing injury severity
                                           Scale.                       based on an ordinal scale. An MAIS 1
                                                                        injury is a minor injury and an MAIS 5
                                                                        injury is a critical injury.
NCAP....................................  New Car Assessment Program.
PAEB....................................  Pedestrian AEB.............  Activates when a crash imminent situation
                                                                        occurs between the equipped vehicle and
                                                                        a pedestrian in the forward path.
RFC.....................................  Request for Comments.......
VTD.....................................  Vehicle Test Device........  A test device used to test AEB system
                                                                        performance.
----------------------------------------------------------------------------------------------------------------

II. Safety Problem

    There were 38,824 fatalities in motor vehicle crashes on U.S.
roadways in 2020 and early estimates put the number of fatalities at
42,915 for 2021.\16\ This is the highest number of fatalities since
2005. While the upward trend in fatalities may be related to increases
in risky driving behaviors during the COVID-19 pandemic,\17\ agency
data show an increase of 3,356 fatalities between 2010 and 2019.\18\
Motor vehicle crashes have also trended upwards since 2010, which
corresponds to an increase in fatalities, injuries, and property
damage.
---------------------------------------------------------------------------

    \16\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813266, https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813283.
    \17\ These behaviors relate to increases in impaired driving,
the non-use of seat belts, and speeding. NHTSA also cited external
studies from telematics providers that suggested increased rates of
cell phone manipulation during driving in the early part of the
pandemic.
    \18\ NHTSA's Traffic Safety Facts Annual Report, Table 2,
https://cdan.nhtsa.gov/tsftables/tsfar.htm#. Accessed March 28,
2023.
---------------------------------------------------------------------------

A. Overall Rear-End Crash Problem

    This NPRM proposes a new FMVSS to reduce the frequency and severity
of vehicle-to-vehicle rear-end crashes and to reduce the frequency and
severity of vehicle crashes into pedestrians. NHTSA uses data from its
Fatality Analysis Reporting System (FARS) and the Crash Report Sampling
System (CRSS) to account for and understand motor vehicle crashes. As
defined in a NHTSA technical manual relating to data entry for FARS and
CRSS, rear-end crashes are incidents where the first event is defined
as the frontal area of one vehicle striking a vehicle ahead in the same
travel lane. In a rear-end crash, as instructed by the 2020 FARS/CRSS
Coding and Validation Manual, the vehicle ahead is categorized as
intending to head either straight, left or right, and is either
stopped, travelling at a lower speed, or decelerating.\19\
---------------------------------------------------------------------------

    \19\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813251 Category II Configuration D. Rear-End.
---------------------------------------------------------------------------

    In 2019, rear-end crashes accounted for 32.5 percent of all
crashes, making them the most prevalent type of crash.\20\ Fatal rear-
end crashes increased from 1,692 in 2010 to 2,363 in 2019 and accounted
for 7.1 percent of all fatal crashes in 2019, up from 5.6 percent in
2010. Because data from 2020 and 2021 may not be representative of the
general safety problem due to the COVID-19 pandemic, the following
discussion refers to data from 2010 to 2020 when discussing rear-end
crash safety problem trends, and 2019 data when discussing specific
characteristics of the rear-end crash safety problem. While injury and
property damage-only rear-end crashes from 2010 (476,000 and 1,267,000,
respectively) and 2019 (595,000 and 1,597,000, respectively) are not
directly comparable due to the difference in database structure and
sampling, the data indicate that these numbers have not significantly
changed from 2010-2015 (NASS-GES sampling) and 2016-2019 (CRSS
sampling).
---------------------------------------------------------------------------

    \20\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141 Traffic Safety Facts 2019, Table 29.
    \21\ Compiled from NHTSA's Traffic Safety Facts Annual Report,
Table 29 from 2010 to 2020, https://cdan.nhtsa.gov/tsftables/tsfar.htm#. Accessed March 28, 2023.

                   Table 6--2010-2020 Rear-End Crashes All Vehicle Types by Crash Severity 21
----------------------------------------------------------------------------------------------------------------
                                                                      Rear-end crash severity
                                                 ---------------------------------------------------------------
                                                       Fatal          Injury         Property-    Total rear-end
               First harmful event               --------------------------------   damage-only  ---------------
                                                                                ----------------
                                                      Number          Number          Number          Number
----------------------------------------------------------------------------------------------------------------
2010............................................           1,692         476,000       1,267,000       1,745,000
2011............................................           1,808         475,000       1,245,000       1,721,000
2012............................................           1,836         518,000       1,327,000       1,847,000
2013............................................           1,815         503,000       1,326,000       1,831,000
2014............................................           1,971         522,000       1,442,000       1,966,000
2015............................................           2,225         556,000       1,543,000       2,101,000
2016............................................           2,372         661,000       1,523,000       2,187,000
2017............................................           2,473         615,000       1,514,000       2,132,000
2018............................................           2,459         594,000       1,579,000       2,175,000
2019............................................           2,363         595,000       1,597,000       2,194,000
2020............................................           2,428         417,000       1,038,000       1,457,000
----------------------------------------------------------------------------------------------------------------

    Table 7 presents a breakdown of all the crashes in 2019 by the
first harmful event where rear-end crashes represent 7.1 percent of the
fatal crashes, 31.1 percent of injury crashes and 33.2 percent (or the
largest percent) of property damage only crashes.

            Table 7--2019 Crashes, by First Harmful Event, Manner of Collision, and Crash Severity 22
----------------------------------------------------------------------------------------------------------------
                                                                   Crash severity
                                   -----------------------------------------------------------------------------
        First harmful event                   Fatal                    Injury             Property damage only
                                   -----------------------------------------------------------------------------
                                       Number      Percent       Number      Percent       Number      Percent
----------------------------------------------------------------------------------------------------------------
Collision with Motor Vehicle in
 Transport
    Angle.........................        6,087         18.2      531,000         27.7      956,000         19.9
    Rear-end......................        2,363          7.1      595,000         31.1    1,597,000         33.2
    Sideswipe.....................          917          2.7      138,000          7.2      739,000         15.4
    Head On.......................        3,639         10.9       91,000          4.7       86,000          1.8
    Other/Unknown.................          150          0.4        8,000          0.4       69,000          1.4
Collision with a Fixed Object
 Collision with Object Not Fixed
                                          9,579         28.6      281,000         14.7      657,000         13.7
                                          7,826         23.4      214,000         11.2      648,000         13.5
Non-collision.....................        2,870          8.6       58,000          3.0       54,000          1.1
----------------------------------------------------------------------------------------------------------------

    The following paragraphs provide a breakdown of rear-end crashes by
vehicle type, posted speed limit, light conditions and atmospheric
conditions for the year 2019 based on NHTSA's FARS, CRSS and the 2019
Traffic Safety Facts sheets.
---------------------------------------------------------------------------

    \22\ NHTSA's Traffic Safety Facts Annual Report, Table 29 for
2019, https://cdan.nhtsa.gov/tsftables/tsfar.htm#. Accessed March
28, 2023.
---------------------------------------------------------------------------

B. Rear-End Crashes by Vehicle Type

    In 2019, passenger cars and light trucks were involved in the vast
majority of rear-end crashes. NHTSA's ``Manual on Classification of
Motor Vehicle Traffic Accidents'' provides a standardized method for
crash reporting. It defines passenger cars as ``motor vehicles used
primarily for carrying passengers, including convertibles, sedans, and
station wagons,'' and light trucks as ``trucks of 10,000 pounds gross
vehicle weight rating or less, including pickups, vans, truck-based
station wagons, and utility vehicles.'' \23\ The 2019 data show that
crashes where a passenger car or light truck is a striking vehicle
represent at least 70 percent of fatal rear-end crashes, 95 percent of
crashes resulting in injury, and 96 percent of damage only crashes (See
Table 8).\24\
---------------------------------------------------------------------------

    \23\ https://www-fars.nhtsa.dot.gov/help/terms.aspx.
    \24\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141 Traffic Safety Facts 2019.

               Table 8--Rear-End Crashes With Impact Location--Front, by Vehicle Type, in 2019 25
----------------------------------------------------------------------------------------------------------------
                                                                                Property
             Vehicle body type, initial impact-front                   Fatal          Injury        damage only
----------------------------------------------------------------------------------------------------------------
Passenger Car...................................................             888         329,000         906,000
Light Truck.....................................................             910         245,000         642,000
All Other.......................................................             762          31,000          57,000
----------------------------------------------------------------------------------------------------------------

C. Rear-End Crashes by Posted Speed Limit

    When looking at posted speed limit and rear-end crashes, data show
that the majority of the crashes happened in areas where the posted
speed limit was 60 mph (97 km/h) or less. Table 9 shows the rear-end
crash data by posted speed limit and vehicle type from 2019. About 60
percent of fatal crashes were on roads with a speed limit of 60 mph (97
km/h) or lower. That number is 73 percent for injury crashes and 78
percent for property damage-only crashes.
---------------------------------------------------------------------------

    \25\ Generated from FARS and CRSS databases (https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/,
https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/,
accessed October 17, 2022).

  Table 9--2019 Rear-End Crashes Involving Passenger Cars, MPVs, and Light Trucks With Frontal Impact by Posted
                                                Speed Limit 26 27
----------------------------------------------------------------------------------------------------------------
                                                   Passenger cars, light trucks, by crash severity
                                   -----------------------------------------------------------------------------
  Vehicles by posted speed limit              Fatal                    Injury             Property-damage-only
                                   -----------------------------------------------------------------------------
                                       Number      Percent       Number      Percent       Number      Percent
----------------------------------------------------------------------------------------------------------------
25 mph or less....................           16            1       28,000            5      103,000            7
30................................           30            2       24,000            4       78,000            5
35................................           95            5       91,000           16      267,000           17
40................................           87            5       66,000           11      175,000           11
45................................          223           12      129,000           22      373,000           24

50................................           99            6       19,000            3       58,000            4
55................................          401           22       55,000           10      122,000            8
60................................          133            7       12,000            2       31,000            2
65 and above......................          684           38       75,000           13      153,000           10
All other.........................           30            2       75,000           13      187,000           12
                                   -----------------------------------------------------------------------------
    Total.........................        1,798          100      574,000          100    1,547,000          100
----------------------------------------------------------------------------------------------------------------

D. Rear-End Crashes by Light Condition

    Slightly more fatal rear-end crashes (51 percent) occurred during
daylight than during dark-lighted and dark-not-lighted conditions
combined (43 percent) in 2019. However, injury and property damage-only
rear-end crashes were reported to have happened overwhelmingly during
daylight, at 76 percent for injury rear-end crashes and 80 percent for
property-damage-only rear-end crashes. Table 10 presents a summary of
all 2019 rear-end crashes of light vehicles by light conditions, where
the impact location is the front of a light vehicle.
---------------------------------------------------------------------------

    \26\ Generated from FARS and CRSS databases (https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/,
https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/,
accessed October 17, 2022).
    \27\ Total percentages may not equal the sum of individual
components due to independent rounding throughout the Safety Problem
section.
    \28\ Generated from FARS and CRSS databases (https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/,
https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/,
accessed October 17, 2022).

             Table 10--2019 Rear-End Crashes With Light Vehicle Front Impact, by Light Condition 28
----------------------------------------------------------------------------------------------------------------
                                                                Crash severity
                             -----------------------------------------------------------------------------------
       Light condition                  Fatal                      Injury                Property Damage-only
                             -----------------------------------------------------------------------------------
                                Percent       Number      Percent        Number          Percent        Number
----------------------------------------------------------------------------------------------------------------
Daylight....................          925           51      436,000              76       1,232,000           80
Dark--Not Lighted...........          438           24       28,000               5    59,00060,767            4
Dark--Lighted...............          349           19       86,000              15         192,000           12
All Other...................           86            5       24,000               4          65,000            4
                             -----------------------------------------------------------------------------------
    Total...................        1,798          100      574,000             100       1,547,000          100
----------------------------------------------------------------------------------------------------------------

E. Rear-End Crashes by Atmospheric Conditions

    In 2019, the majority of rear-end crashes of light vehicles were
reported to occur during clear skies with no adverse atmospheric
conditions. These conditions were present for 72 percent of all fatal
rear-end crashes, while 14 percent of fatal rear-end crashes were
reported to occur during cloudy conditions. Similar trends are reported
for injury and property damage only crashes. A brief summary of 2019
rear-end crashes of light vehicle with frontal impact by atmospheric
conditions is presented in Table 11.
---------------------------------------------------------------------------

    \29\ Generated from FARS and CRSS databases (https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/,
https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/,
accessed October 17, 2022).

   Table 11--2019 Rear-End Crashes Involving Light Vehicles With Frontal Impact, by Atmospheric Conditions 29
----------------------------------------------------------------------------------------------------------------
                                                                   Crash severity
                                   -----------------------------------------------------------------------------
  Crashes atmospheric conditions              Fatal                    Injury             Property damage-only
                                   -----------------------------------------------------------------------------
                                      Percent       Number      Percent       Number      Percent       Number
----------------------------------------------------------------------------------------------------------------
Clear, No Adverse.................        1,295           72      426,000           74    1,113,000           72
Cloudy............................          247           14       87,000           15      245,000           16
All Other.........................          256           14       61,000           11      189,000           12
                                   -----------------------------------------------------------------------------
    Total.........................        1,798          100      574,000          100    1,547,000          100
----------------------------------------------------------------------------------------------------------------

F. Pedestrian Fatalities and Injuries

    While the number of fatalities from motor vehicle traffic crashes
is increasing, pedestrian fatalities are increasing at a greater rate
than the general trend and becoming a larger percentage of total
fatalities. In 2010, there were 4,302 pedestrian fatalities (13 percent
of all fatalities), which has increased to 6,272 (17 percent of all
fatalities) in 2019. The latest agency estimation data indicate that
there were 7,342 pedestrian fatalities in 2021.\30\ Since data from
2020 and 2021 may not be representative of the general safety problem
due to the COVID-19 pandemic, the following sections refer to data from
2010 to 2020 when discussing pedestrian safety problem trends, and 2019
data when discussing specific characteristics of the pedestrian safety
problem. While the number of pedestrian fatalities is increasing, the
number of pedestrians injured in crashes from 2010 to 2020 has not
changed significantly, with exception of the 2020 pandemic year. In
Table 12, the number and percentage of pedestrian fatalities and
injuries for the 2010 to 2020 period is presented in relationship to
the total number of fatalities and total number of people injured in
all crashes.
---------------------------------------------------------------------------

    \30\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813298 Early Estimates of Motor Vehicle Traffic
Fatalities And Fatality Rate by Sub-Categories in 2021, May 2022.
    \31\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813079 Pedestrian Traffic Facts 2019 Data, May 2021,
https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813310
Pedestrian Traffic Facts 2020, Data May 2022.

   Table 12--2010-2020 Traffic Crash Fatalities and Pedestrian Fatalities, and Injured People and Pedestrians
                                                   Injured 31
----------------------------------------------------------------------------------------------------------------
                                                  Pedestrian fatalities 1                 Pedestrian injured 2
                                                                              Total    -------------------------
                                       Total    --------------------------    people
               Year                fatalities 1                Percent of   injured 2                 Percent of
                                                    Number       total                     Number       total
                                                               fatalities                              injured
----------------------------------------------------------------------------------------------------------------
2010.............................        32,999        4,302           13    2,248,000       70,000            3
2011.............................        32,479        4,457           14    2,227,000       69,000            3
2012.............................        33,782        4,818           14    2,369,000       76,000            3
2013.............................        32,893        4,779           15    2,319,000       66,000            3
2014.............................        32,744        4,910           15    2,343,000       65,000            3
2015.............................        35,484        5,494           15    2,455,000       70,000            3
2016.............................        37,806        6,080           16    3,062,000       86,000            3
2017.............................        37,473        6,075           16    2,745,000       71,000            3
2018.............................        36,835        6,374           17    2,710,000       75,000            3
2019.............................        36,355        6,272           17    2,740,000       76,000            3
2020.............................        38,824        6,516           17    2,282,015       55,000            2
----------------------------------------------------------------------------------------------------------------
1 Data source: FARS 2010-2019, 2020 Annual Report (ARF).
2 Data source: NASS GES 2010-2015, CRSS 2016-2019.

    The following sections present a breakdown of pedestrian fatalities
and injuries by initial impact point, vehicle type, posted speed limit,
lighting condition, pedestrian age, and light conditions for the year
2019.

G. Pedestrian Fatalities and Injuries by Initial Point of Impact and
Vehicle Type

    In 2019, the majority of pedestrian fatalities, 4,638 (74 percent
of all pedestrian fatalities), and injuries, 52,886 (70 percent of all
pedestrian injuries), were in crashes where the initial point of impact
on the vehicle was the front. When the crashes are broken down by
vehicle body type, the majority of pedestrian fatalities and injuries
occur where the initial point of impact was the front of a light
vehicle (4,069 pedestrian fatalities and 50,831 pedestrian injuries)
(see Table 13).32
---------------------------------------------------------------------------

    \32\ As described previously, passenger cars and light trucks
are the representative population for vehicles with a GVWR of 4,536
kg (10,000 lbs.) or less.
    \33\ NHTSA's Traffic Safety Facts Annual Report, Table 99 for
2019, https://cdan.nhtsa.gov/tsftables/tsfar.htm#Accessed March 28,
2023.

  Table 13--2019 Pedestrian Fatalities and Injuries, by Initial Point of Impact Front and Vehicle Body Type 33
----------------------------------------------------------------------------------------------------------------
                                                                          Crash severity
                                                 ---------------------------------------------------------------
    Vehicle body type, initial impact--front           Pedestrian fatalities            Pedestrian injuries
                                                 ---------------------------------------------------------------
                                                      Number          Percent         Number          Percent
----------------------------------------------------------------------------------------------------------------
Passenger Car...................................           1,976              43          30,968              59
Light Truck.....................................           2,093              45          19,863              38
All Other.......................................             569              12           2,055               4
                                                 ---------------------------------------------------------------
    Total.......................................           4,638             100          52,886             100
----------------------------------------------------------------------------------------------------------------

H. Pedestrian Fatalities and Injuries by Posted Speed Limit Involving
Light Vehicles

    In 2019, the majority of pedestrian fatalities from crashes
involving light vehicles with the initial point of impact as the front
occurred on roads where the posted speed limit was 45 mph or less,
(about 70 percent). There is a near even split between the number of
pedestrian fatalities in 40 mph and lower speed zones and in 45 mph and
above speed zones (50 percent and 47 percent respectively with the
remaining unknown, not reported or lacking). As

for pedestrian injuries, in a large number of cases, the posted speed
limit is either not reported or unknown (i.e., about 34 percent of the
sampled data). In situations where the posted speed limit is known, 57
percent of the pedestrians were injured when the posted speed limit was
40 mph or below, and 9 percent when the posted speed limit was above 40
mph. Table 14 shows the number of pedestrian fatalities and injuries
for each posted speed limit.
---------------------------------------------------------------------------

    \34\ The accompanying PRIA estimates the impacts of the rule
based on the estimated travel speed of the striking vehicle. This
table presents the speed limit of the roads on which pedestrian
crashes occur.

      Table 14--2019 Pedestrian Fatalities and Injuries Involving Light Vehicles, by Posted Speed Limit 34
----------------------------------------------------------------------------------------------------------------
                                                                          Crash severity
                                                 ---------------------------------------------------------------
               Posted speed limit                     Pedestrians fatalities            Pedestrian injuries
                                                 ---------------------------------------------------------------
                                                      Number          Percent         Number          Percent
----------------------------------------------------------------------------------------------------------------
5 mph...........................................               3            0.07             185            0.36
10 mph..........................................               7            0.17             287            0.56
15 mph..........................................              10            0.25             865            1.70
20 mph..........................................              14            0.34             479            0.94
25 mph..........................................             346            8.50           9,425           18.54
30 mph..........................................             325            7.99           4,254            8.37
35 mph..........................................             765           18.80           9,802           19.28
40 mph..........................................             551           13.54           3,703            7.28
45 mph..........................................             821           20.18           3,094            6.09
50 mph..........................................             177            4.35             302            0.59
55 mph..........................................             463           11.38             546            1.07
60 mph..........................................             105            2.58             130            0.26
65 mph..........................................             199            4.89             241            0.47
70 mph..........................................             103            2.53             105            0.21
75 mph..........................................              19            0.47               4            0.01
80 mph..........................................               2            0.05              25            0.05
Not Reported....................................             118            2.90          15,017           29.54
Unknown.........................................              16            0.39             176            0.35
No Statutory Limit/Non-Trafficway Area..........              25            0.61           2,191            4.31
                                                 ---------------------------------------------------------------
    Total.......................................           4,069             100          50,831             100
----------------------------------------------------------------------------------------------------------------

I. Pedestrian Fatalities and Injuries by Lighting Condition Involving
Light Vehicles

    The majority of pedestrian fatalities where a light vehicle strikes
a pedestrian with the front of the vehicle occurred in dark lighting
conditions, 3,131 (75 percent). There were 20,645 pedestrian injuries
(40 percent) in dark lighting conditions and 27,603 pedestrian injuries
(54 percent) in daylight conditions.
---------------------------------------------------------------------------

    \35\ Generated from FARS and CRSS databases (https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/,
https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/,
accessed October 17, 2022).

      Table 15--2019 Pedestrian Fatalities and Injuries Involving Light Vehicles, by Lighting Condition 35
----------------------------------------------------------------------------------------------------------------
                                                                          Crash severity
                                                 ---------------------------------------------------------------
                 Light condition                       Pedestrian fatalities            Pedestrian injuries
                                                 ---------------------------------------------------------------
                                                      Number          Percent         Number          Percent
----------------------------------------------------------------------------------------------------------------
Daylight........................................             767              19          27,603              54
Dark-Not Lighted................................           1,464              36           4,551               9
Dark-Lighted....................................           1,621              40          15,996              31
Dark-Unknown Light..............................              46               1              98               0
All Other.......................................             171               4           2,583               5
                                                 ---------------------------------------------------------------
    Total.......................................           4,069             100          50,831             100
----------------------------------------------------------------------------------------------------------------

J. Pedestrian Fatalities and Injuries by Age Involving Light Vehicles

    In 2019, 646 fatalities and approximately 106,600 injuries involved
children aged 9 and below. Of these, 68 fatalities and approximately
2,700 injuries involved pedestrians aged 9 and below in crashes with
the front of a light vehicle. As shown in Table 16, the first two age
groups (less than age 5 and 5 to 9) each represent less than 1 percent
of the total pedestrian fatalities in crashes with the front of a light
vehicle. These age groups also represent about 1.5 and 3.8 percent of
the total pedestrian injuries in crashes with the front of a light
vehicle, respectively. In contrast, age groups between age 25 and 69
each represent approximately 7 percent of the total pedestrian
fatalities in crashes with the front of a light vehicle, with the 55 to
59 age group having the highest percentage at 10.9 percent. Pedestrian
injury percentages

were less consistent, but distributed similarly, to pedestrian
fatalities, with lower percentages reflected in children aged 9 and
below and adults over age 70.
---------------------------------------------------------------------------

    \36\ Generated from FARS and CRSS databases (https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/,
https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/,
accessed October 17, 2022).
    \37\ https://www.census.gov/data/tables/2019/demo/age-and-sex/2019-age-sex-composition.html, Table 12.

   Table 16--2019 Pedestrians Fatalities and Injuries in Traffic Crashes Involving Light Vehicles by Initial Point of Impact Front 36 and Age Group 37
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Pedestrian fatalities          Pedestrians injuries
                                                                                ------------------------------------------------------------
                                                                                Percent of                      Percent of
                                                                United States                   Light          total                           total
                          Age group                               population     Percent of    vehicle      pedestrian     Light vehicle    pedestrian
                                                                  (thousand)     population     front-     fatalities in   front-impact     injuries in
                                                                                impact ped.   light vehicle   ped. injuries   light vehicle
                                                                                fatalities   front-impact                    front-impact
                                                                                crashes                         crashes
--------------------------------------------------------------------------------------------------------------------------------------------------------
<5...........................................................           19,736          6.1           37             0.9             770             1.5
5-9..........................................................           20,212          6.2           31             0.8           1,907             3.8
10-14........................................................           20,827          6.4           58             1.4           2,830             5.6
15-20........................................................           20,849          6.4          159             3.9           5,673            11.2
21-24........................................................           21,254          6.6          173             4.3           3,190             6.3
25-29........................................................           23,277          7.2          287             7.1           4,394             8.6
30-34........................................................           21,932          6.8          315             7.7           3,735             7.3
35-39........................................................           21,443          6.6          316             7.8           3,636             7.2
40-44........................................................           19,584          6.0          277             6.8           2,812             5.5
45-49........................................................           20,345          6.3          294             7.2           2,745             5.4
50-54........................................................           20,355          6.3          350             8.6           3,311             6.5
55-59........................................................           21,163          6.5          442            10.9           3,678             7.2
60-64........................................................           20,592          6.3          379             9.3           3,469             6.8
65-69........................................................           17,356          5.4          303             7.4           2,594             5.1
70-74........................................................           14,131          4.4          207             5.1           1,724             3.4
75-79........................................................            9,357          2.9          172             4.2           1,136             2.2
80+..........................................................           11,943          3.7          252             6.2           1,127             2.2
Unknown......................................................  ...............  ...........           17             0.4           2,103             4.1
                                                              ------------------------------------------------------------------------------------------
    Total....................................................  ...............  ...........        4,069             100          50,831             100
--------------------------------------------------------------------------------------------------------------------------------------------------------

K. AEB Target Population

    AEB technology is not expected to prevent all rear-end crashes or
pedestrian fatalities. In order to determine the portion of the rear-
end and pedestrian fatality population that could be affected by AEB,
NHTSA used the FARS and CRSS databases to derive a target population.
    Fatality data were derived from FARS and data on property damage
vehicle crashes and injuries were derived from CRSS. The agency
computed annualized averages for years 2016 to 2019 from fatalities and
injuries.
    For lead vehicle AEB, NHTSA first applied filters to ensure the
target population included only rear-end crashes, excluding crashes
other than those resulting from a motor vehicle in transport and only
including crashes where the striking vehicle had frontal damage and the
struck vehicle had rear-end damage. NHTSA conservatively excluded
crashes with more than two vehicles because two-vehicle crashes most
closely mirror the test track testing which includes a single lead
vehicle. NHTSA only included crashes where a light vehicle struck
another light vehicle. The striking vehicle was limited to light
vehicles because this proposal would only apply to light vehicles. The
struck vehicle was limited to light vehicles because the specifications
for the lead vehicle in testing were derived exclusively from light
vehicles. The crash population was further limited to cases where the
subject vehicle was traveling in a straight line and either braked or
did not brake to avoid the crash (excluding instances where the vehicle
attempted to avoid the crash in some other manner). These exclusions
were applied because AEB systems may suppress automatic braking when
the driver attempts to avoid a collision by some other action, such as
turning. Finally, the crash scenarios were limited to those where the
lead vehicle was either stopped, moving, or decelerating along the same
path as the subject vehicle. Other maneuvers, such as crashes in which
the vehicle turned prior to the crash, were excluded because current
sensor systems have a narrow field of view that does not provide
sufficient information to the perception system regarding objects in
the vehicle's turning path.
    For PAEB, the target population was also identified based on
reported fatalities (in FARS data) and injuries (in GES and CRSS data).
Each of the estimated target population values were based on a six-year
average (2014 through 2019). NHTSA applied filters such that only
crashes involving a single light vehicle and pedestrians where the
first harmful event was contact with the pedestrian are considered in
the analysis. Further, the impact area was restricted to the front of
the vehicle because the performance proposed in this rule is limited to
forward vehicle movement. Additionally, the vehicle's pre-event
movement (i.e., the vehicle's activity prior to the driver's
realization of the impending crash) was traveling in a straight line
and the pedestrian movement was determined to be either crossing the
vehicle's path or along the vehicle's path to match the track testing
being proposed.
    After applying these filters, NHTSA has tentatively concluded that
AEB technology could potentially address up to 3,036 fatalities (394
lead vehicle and 2,642 pedestrian), 160,309 injuries (142,611 lead
vehicle and 17,698 pedestrian), and 1,119,470 property damage only
crashes (only lead vehicle). These crashes represent 15 percent and 14
percent of fatalities and injuries resulting from rear end crashes,

respectively and 43 percent and 28 percent of fatalities and injuries
from pedestrian crashes. These crashes also represent 8.4 percent of
total roadway fatalities, 5.9 percent of total roadway injuries, and 23
percent of property damage only crashes.
    NHTSA has restricted the target population to two-vehicle crashes
although FCW and AEB would likely provide safety benefits in multi-
vehicle crashes even when the first impact would be completely avoided
with FCW and AEB.\38\ NHTSA also limited the target population to light
vehicle to light vehicle crashes because NHTSA does not have data on
how AEB systems would respond to other vehicle types such as heavy
vehicles or motorcycles. NHTSA is currently researching light vehicle
AEB performance in these situations.
---------------------------------------------------------------------------

    \38\ As discussed in the PRIA for this NPRM, NHTSA decided not
to include multi-vehicle crashes in the target population because it
would be difficult to estimate safety benefits for occupants in the
second and or third vehicles due to limited data.
---------------------------------------------------------------------------

III. Data on Effectiveness of AEB in Mitigating Harm

    Forward collision warning systems were among the first generation
of advanced driver assistance system technologies designed to help
drivers avoid an impending crash.\39\ In 2008, when NHTSA decided to
include ADAS technologies in the NCAP program, FCW was selected because
the agency believed (1) this technology addressed a major crash
problem; (2) system designs existed that could mitigate this safety
problem; (3) safety benefit projections were assessed; and (4)
performance tests and procedures were available to ensure an acceptable
performance level. At the time, the agency estimated that FCW systems
were 15 percent effective in preventing rear-end crashes. More
recently, in a 2017 study, the Insurance Institute for Highway Safety
(IIHS) found that FCW systems may be more effective than NHTSA's
initial estimates indicated.\40\ IIHS found that FCW systems reduced
rear-end crashes by 27 percent.
---------------------------------------------------------------------------

    \39\ ADAS technologies use advanced technologies to assist
drivers in avoiding a crash. NCAP currently recommends four kinds of
ADAS technologies to prospective vehicle purchasers--forward
collision warning, lane departure warning, crash imminent braking,
and dynamic brake support (the latter two are considered AEB).
https://www.nhtsa.gov/equipment/driver-assistance-technologies. In a
March 2, 2022 request for comments notice, infra, NHTSA proposed to
add four more ADAS technologies to NCAP.
    \40\ Cicchino, J.B. (2017, February), Effectiveness of forward
collision warning and autonomous emergency braking systems in
reducing front-to-rear crash rates, Accident Analysis and
Prevention, 2017 Feb;99(Pt A):142-152. https://doi.org/10.1016/j.aap.2016.11.009.
---------------------------------------------------------------------------

    When FCW is coupled with AEB, the system becomes more effective at
reducing rear-end crashes. A limitation of FCW systems is that they are
designed only to warn the driver, but they do not provide automatic
braking of the vehicle. From a functional perspective, research
suggests that active braking systems, such as AEB, provide greater
safety benefits than corresponding warning systems, such as FCW. In a
recent study sponsored by General Motors (GM) to evaluate the real-
world effectiveness of ADAS technologies (including FCW and AEB) on 3.8
million model year 2013-2017 GM vehicles, the University of Michigan's
Transportation Research Institute (UMTRI) found that, for frontal
collisions, camera-based FCW systems produced an estimated 21 percent
reduction in rear-end striking crashes, while the AEB systems studied
(which included a combination of camera-only, radar-only, and fused
camera-radar systems) produced an estimated 46 percent reduction in the
same crash type.\41\ Similarly, in a 2017 study, IIHS found that
vehicles equipped with FCW and AEB showed a 50 percent reduction for
the same crash type.\42\
---------------------------------------------------------------------------

    \41\ The Agency notes that the FCW effectiveness rate (21%)
observed by UMTRI is similar to that observed by IIHS in its 2019
study (27%). Differences in data samples and vehicle selection may
contribute to the specific numerical differences. Regardless, the
AEB effectiveness rate observed by UMTRI (46%) was significantly
higher than the corresponding FCW effectiveness rate observed in
either the IIHS or UMTRI study.
    \42\ Cicchino, J.B. (2017, February), Effectiveness of forward
collision warning and autonomous emergency braking systems in
reducing front-to-rear crash rates, Accident Analysis and
Prevention, 2017 Feb;99(Pt A):142-152, https://doi.org/10.1016/j.aap.2016.11.009.
---------------------------------------------------------------------------

    NHTSA has found that current AEB systems often integrate the
functionalities of FCW and AEB into one frontal crash prevention system
to deliver improved real-world safety performance. Consequently, NHTSA
believes that FCW should now be considered a component of lead vehicle
AEB and PAEB, and has, in fact, developed a test in NCAP that assesses
FCW in the same test that evaluates a vehicle's AEB and PAEB
performance.\43\
---------------------------------------------------------------------------

    \43\ 87 FR 13486 March 9, 2022, proposed update to NCAP's FCW
testing.
---------------------------------------------------------------------------

    Not only are AEB systems proving effective, data indicate there is
high consumer acceptance of the current systems. In a 2019 subscriber
survey by Consumer Reports, 81 percent of vehicle owners reported that
they were satisfied with AEB technology, 54 percent said that it had
helped them avoid a crash, and 61 percent stated that they trusted the
system to work every time.\44\
---------------------------------------------------------------------------

    \44\ Consumer Reports, (2019, August 5), Guide to automatic
emergency braking: How AEB can put the brakes on car collisions,
https://www.consumerreports.org/car-safety/automatic-emergency-braking-guide/.
---------------------------------------------------------------------------

    However, NHTSA is aware of data and other information indicating
potential opportunities for AEB improvement. The data indicate the
potential of AEB to reduce fatal crashes, especially if AEB systems
performed at higher speeds. While AEB systems on currently available
vehicles are highly effective at lower speed testing, some such systems
do not perform well in tests done at higher speeds.

IV. NHTSA's Earlier Efforts Related to AEB

    NHTSA sought to provide the public with valuable vehicle safety
information by actively supporting development and implementation of
AEB technologies through research and development and through NHTSA's
NCAP. NHTSA also sought to incentivize installation of AEB and PAEB on
vehicles by encouraging the voluntary installation of AEB systems by
automakers through a voluntary industry commitment, resulting in
participating automakers committing to installing an AEB system that
met certain performance thresholds on most light duty cars and trucks
by September 1, 2022, and on nearly all light vehicles by September 1,
2025.

A. NHTSA's Foundational AEB Research

    NHTSA conducted extensive research on AEB systems to support
development of the technology and eventual deployment in vehicles.
There were three main components to this work. The agency conducted
early research on FCW systems that warn drivers of potential rear-end
crashes with other vehicles. This was followed by research into AEB
systems designed to prevent or mitigate rear-end collisions through
automatic braking. Later, NHTSA evaluated AEB systems designed to
prevent or mitigate collisions with pedestrians in a vehicle's forward
path.
1. Forward Collision Warning Research
    NHTSA's earliest research on FCW systems began in the 1990s, at a
time when the systems were under development and evaluation had been
conducted primarily by suppliers and vehicle manufacturers. NHTSA
collaborated with industry stakeholders to identify the specific crash
types that an FCW system could be designed to address, the resulting
minimum functional requirements, and potential

objective test procedures for evaluation.\45\ In the late 1990s, NHTSA
worked with industry to conduct a field study, the Automotive Collision
Avoidance System Program. NHTSA later contracted with the Volpe
National Transportation Systems Center (Volpe) to conduct analyses of
data recorded during that field study.\46\ From this work, NHTSA
learned about the detection and alert timing and information about
warning signal modality (auditory, visual, etc.) of FCW systems, and
predominant vehicle crash avoidance scenarios where FCW systems could
most effectively play a role in alerting a driver to brake and avoid a
crash. In 2009, NHTSA synthesized this research in the development and
conduct of controlled track test assessments on three vehicles equipped
with FCW.\47\
---------------------------------------------------------------------------

    \45\ This research was documented in a report, ``Development and
Validation of Functional Definitions and Evaluation Procedures for
Collision Warning/Avoidance Systems,'' Kiefer, R., et al., DOT HS
808 964, August 1999. Additional NHTSA FCW research is described in
Zador, Pub. L., et al., ``Final Report--Automotive Collision
Avoidance System (ACAS) Program,'' DOT HS 809 080, August 2000; and
Ference, J.J., et al., ``Objective Test Scenarios for Integrated
Vehicle-Based Safety Systems,'' Paper No. 07-0183, Proceedings of
the 20th International Conference for the Enhanced Safety of
Vehicles, 2007.
    \46\ Najm, W.G., Stearns, M.D., Howarth, H., Koopmann, J., and
Hitz, J., ``Evaluation of an Automotive Rear-End Collision Avoidance
System,'' DOT HS 810 569, April 2006 and Najm, W.G., Stearns, M.D.,
and Yanagisawa, M., ``Pre-Crash Scenario Typology for Crash
Avoidance Research,'' DOT HS 810 767, April 2007.
    \47\ Forkenbrock, G., O'Harra, B., ``A Forward Collision Warning
(FCW) Program Evaluation, Paper No. 09-0561, Proceedings of the 21st
International Technical Conference for the Enhanced Safety of
Vehicles, 2009.
---------------------------------------------------------------------------

    Because FCW systems are designed only to warn the driver and not to
provide automatic braking for meaningful speed reduction of the
vehicle, NHTSA continued to research AEB systems.\48\
---------------------------------------------------------------------------

    \48\ Some FCW systems use haptic brake pulses to alert the
driver of a crash-imminent driving situation, but the pulses are not
intended to slow the vehicle.
---------------------------------------------------------------------------

2. AEB Research To Prevent Rear-End Impacts With a Lead Vehicle
    NHTSA's research and test track performance evaluations of AEB
began around 2010. The agency began a thorough examination of the state
of forward-looking advanced braking technologies, analyzing their
performance and identifying areas of concern or uncertainty, to better
understand their safety potential. NHTSA issued a report \49\ and a
request for comments notice seeking feedback on its CIB and DBS
research in July 2012.\50\ Specifically, NHTSA wanted to enhance its
knowledge further and help guide its continued efforts pertaining to
AEB effectiveness, test operation (including how to ensure
repeatability using a target or surrogate vehicle), refinement of
performance criteria, and exploring the need for an approach and
criteria for ``false positive'' tests to minimize the unintended
negative consequences of automatic braking in non-critical driving
situations.
---------------------------------------------------------------------------

    \49\ The agency's initial research and analysis of CIB and DBS
systems were documented in a report, ``Forward-Looking Advanced
Braking Technologies: An analysis of current system performance,
effectiveness, and test protocols'' (June 2012). https://www.regulations.gov, NHTSA 2012-0057-0001.
    \50\ 77 FR 39561.
---------------------------------------------------------------------------

    NHTSA considered feedback it received on the RFC and conducted
additional testing to support further development of the test
procedures. The agency documented its work in two additional reports,
``Automatic Emergency Braking System Research Report'' (August 2014)
\51\ and ``NHTSA's 2014 Automatic Emergency Braking (AEB) Test Track
Evaluations'' (May 2015),\52\ and in accompanying draft CIB and DBS
test procedures.\53\
---------------------------------------------------------------------------

    \51\ https://www.regulations.gov, NHTSA 2012-0057-0037.
    \52\ DOT HS 812 166.
    \53\ https://www.regulations.gov, NHTSA 2012-0057-0038.
---------------------------------------------------------------------------

    In the follow-on tests, NHTSA found that CIB and DBS systems
commercially available on several different production vehicles could
be tested successfully to the agency's defined performance measures.
NHTSA developed performance measures to define the performance CIB and
DBS systems should attain to help drivers avoid or at least mitigate
injury risk in rear-end crashes. The agency found that systems meeting
the performance measures have the potential to reduce the number of
rear-end crashes as well as deaths and injuries that result from these
crashes. NHTSA used the research findings to develop NCAP's procedures
for assessing the performance of vehicles with AEB and other crash-
avoidance technologies \54\ and for testing vehicles at higher speeds.
The findings also provided the foundation to upgrade NCAP's current AEB
tests, as discussed in NHTSA's March 9, 2022, request for comments
notice,\55\ and the development of this NPRM.
---------------------------------------------------------------------------

    \54\ NCAP recommends forward collision warning, lane departure
warning, crash imminent braking and dynamic brake support (AEB) to
prospective vehicle purchasers and identifies vehicles that meet
NCAP performance test criteria for these technologies.
    \55\ 87 FR 13452, March 2, 2022.
---------------------------------------------------------------------------

3. AEB Research To Prevent Vehicle Impacts With Pedestrians
    NHTSA began research on PAEB systems in 2011.\56\ The agency worked
on a project with Volpe and the Crash Avoidance Metrics Partnership
(CAMP) \57\ to develop preliminary PAEB test methods. The goal of the
project was to develop and validate minimum performance requirements
and objective test procedures for forward-looking PAEB systems intended
to address in-traffic, pedestrian crash scenarios.
---------------------------------------------------------------------------

    \56\ At that time, the agency used the term ``pedestrian crash
avoidance and mitigation (PCAM)'' research.
    \57\ The participating companies that worked on this project
included representatives from Continental, Delphi Corporation, Ford
Motor Company, General Motors, and Mercedes-Benz.
---------------------------------------------------------------------------

    As part of this work, Volpe conducted an analysis of available
crash data and found four common pedestrian pre-crash scenarios. These
are when the vehicle is: 1. Heading in a straight line and a pedestrian
is crossing the road; 2. turning right and a pedestrian is crossing the
road; 3. turning left and a pedestrian is crossing the road; and 4.
heading in a straight line and a pedestrian is walking along or against
traffic. Understanding the pre-crash factors associated with pedestrian
crashes led to the development of the draft research test methods, a
set of test equipment requirements, a preliminary evaluation plan, and
development of a 50th percentile adult male mannequin made from closed-
cell foam. The culmination of this work was documented in a research
report, ``Objective Tests for Forward Looking Pedestrian Crash
Avoidance/Mitigation Systems: Final Report'' (June 2014).\58\
---------------------------------------------------------------------------

    \58\ Carpenter, M.G., Moury, M.T., Skvarce, J.R., Struck, M.
Zwicky, T.D., & Kiger, S.M. (2014, June), Objective Tests for
Forward Looking Pedestrian Crash Avoidance/Mitigation Systems: Final
report (Report No. DOT HS 812 040), Washington, DC: National Highway
Traffic Safety Administration.

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

    NHTSA continued to refine the CAMP test procedures in pursuit of
objective and repeatable test procedures using production vehicles
equipped with PAEB systems. In doing so, NHTSA evaluated adult, child,
non-articulating and articulating mannequins, walking and running speed
capabilities, mannequin radar cross section characteristics, and
mannequin position accuracy and control.\59\ The evaluated mannequins
and their characteristics represented the largest portion of the crash
problem. NHTSA also updated its real-world pedestrian crash data
analysis in 2017.\60\
---------------------------------------------------------------------------

    \59\ Albrecht, H., ``Objective Test Procedures for Pedestrian
Automatic Emergency Braking Systems,'' SAE Government/Industry
Meeting, January 25-27, 2017.
    \60\ Yanagisawa, M., Swanson, E., Azeredo, P., Najm, W.,
``Estimation of Potential Safety Benefits for Pedestrian Crash
Avoidance/Mitigation Systems, DOT HS 812 400, April 2017.
---------------------------------------------------------------------------

    In November 2019, NHTSA published a draft research test procedure
that provided the methods and specifications for collecting performance
data on PAEB systems for light vehicles.\61\ The test procedures were
developed to evaluate the PAEB performance in the two most frequent
pre-crash scenarios involving pedestrians: where the pedestrian crosses
the road in front of the vehicle and where the pedestrian walks
alongside the road in the path of the vehicle. NHTSA focused its 2019
draft research test procedures on these two scenarios because a 2017
crash data study suggested they collectively represented 90 percent of
pedestrian fatalities (64 percent and 28 percent, respectively). In
contrast, the study found that the turning right and turning left
scenarios were found to only account for 1 percent and 4 percent of
pedestrian fatalities, respectively. NHTSA further focused the 2019
test procedures on PAEB-addressable crashes. PAEB systems offered at
the time were not offering a wider field of view necessary for
detection and braking in the turning scenarios. These two scenarios
present different challenges due to the relative angles and distances
between subject vehicle and pedestrian and could require additional
hardware resulting in added cost. NHTSA's consideration of including
the turning scenarios is further discussed in the PRIA accompanying
this NPRM. The draft test procedures described in this document rely on
the use of pedestrian mannequins for testing purposes.
---------------------------------------------------------------------------

    \61\ https://regulations.dot.gov, Docket No. NHTSA-2019-0102.
---------------------------------------------------------------------------

4. Bicycle and Motorcycle AEB
    NHTSA is actively conducting research to characterize the
performance of AEB systems in response to bicycle and motorcycles in
the same scenarios as NHTSA's lead vehicle AEB testing, in both
daylight and darkness conditions. NHTSA tested five vehicles with
bicycle and motorcycle AEB and also tested with a vehicle surrogate as
a control for AEB system performance. In addition to characterizing the
performance of the five vehicles, this testing also allows NHTSA to
refine its test procedures to determine whether any changes would be
needed to test bicycle or motorcycle AEB.
    Preliminary results suggest that the lane position of the test
device, the lighting conditions, the positioning of a lead vehicle, and
speed all have a significant effect on the performance of AEB systems
relative to bicycles and motorcycles. However, there is no discernable
pattern across vehicles tested, suggesting that performance is
dependent upon specific test scenario definition. Further, preliminary
testing has raised issues with the design of the bicycle and motorcycle
surrogates and their impact on the vehicles under test. This report is
expected to be completed by the end of 2023. The results from this
research, and other future research, may lead to efforts to define test
procedures, refine the bicycle and motorcycle surrogate devices, and
characterize AEB system performance in response to additional test
devices (scooters, mopeds, wheelchairs, or other assisted walking
devices).

B. NHTSA's New Car Assessment Program

1. FCW Tests
    In 2007, based on the research discussed above, NHTSA issued a
notice requesting public comment on including rear-end crash warning/
avoidance systems in NCAP.\62\ The technology under consideration at
the time included forward vehicle sensing with warning or braking. In
2008, based upon feedback and further agency analysis, NHTSA published
a final decision notice announcing its intent to include FCW in NCAP as
a recommended technology and identify for consumers which vehicles have
the technology.
---------------------------------------------------------------------------

    \62\ 72 FR 3473 (January 25, 2007). NHTSA published a report in
conjunction with this notice titled, ``The New Car Assessment
Program (NCAP); Suggested Approaches for Future Enhancements.''
---------------------------------------------------------------------------

    To ensure that NCAP identified only vehicles that had FCW systems
that satisfied a minimum level of performance, NHTSA adopted specific
performance tests and thresholds and time-to-collision-based alert
criteria that a system had to satisfy to be distinguished in NCAP as a
vehicle equipped with the recommended technology. NCAP informs
consumers that a particular vehicle has a recommended technology when
NHTSA has data verifying that the vehicle's system meets the minimum
performance threshold set by NHTSA for acceptable performance. If a
vehicle's system meets the performance threshold using the test method
NHTSA specifies, NHTSA uses a checkmark to indicate on the NCAP website
that the vehicle is equipped with the technology.\63\
---------------------------------------------------------------------------

    \63\ The March 2022 request for comments notice discusses, among
other things, NHTSA's plan to develop a future rating system for new
vehicles based on the availability and performance of all of the
NCAP-recommended crash avoidance technologies. That is, instead of a
simple checkmark showing the vehicle has a technology (and it meets
the applicable performance test criteria), vehicles would receive a
rating for each technology based on the systems' performance test
criteria in NHTSA's tests. 87 FR 13452 (March 9, 2022).
---------------------------------------------------------------------------

    The performance tests chosen for NCAP consisted of three scenarios
that simulated the most frequent types of light vehicle rear-end
crashes: crashes where a vehicle ahead is either stopped, suddenly
starts braking, or is traveling at a much lower speed in the subject
vehicle travel lane. The scenarios were named ``lead vehicle stopped,''
``lead vehicle decelerating,'' and ``lead vehicle moving,''
respectively.\64\ In each scenario, the time needed for a driver to
perceive an impending rear-end crash, decide the corrective action, and
respond with the appropriate mitigating action is prescribed. If the
FCW system fails to provide an alert within the required time during
testing, the professional test driver applies the brakes or steers away
to avoid a collision.
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    \64\ 73 FR 40016 (July 11, 2008). https://regulations.gov.
Docket No. NHTSA-2006-26555-0118.
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2. Lead Vehicle AEB Tests
    NHTSA incorporated AEB technologies (CIB and DBS) in NCAP as
recommended crash avoidance technologies in 2015,\65\ starting with
model year 2018 vehicles. NHTSA adopted performance tests and
thresholds that a system must meet for the vehicle to be distinguished
in NCAP as a vehicle with the recommended technology. The AEB
performance tests consisted of test scenarios and test speeds that were
derived from crash statistics, field operational tests, and NHTSA
testing experience, including

experience gained from development of the FCW performance tests already
in NCAP.\66\ In the NCAP recommended crash avoidance technologies
program, vehicles receive credit for meeting the agency's performance
tests for CIB and DBS separately.
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    \65\ 80 FR 68604.
    \66\ Id. at 68608.
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    For AEB assessment, NCAP uses four test scenarios: lead vehicle
stopped, lead vehicle decelerating, lead vehicle moving, and the steel
trench plate test.\67\ Each test scenario is evaluated separately for
CIB and DBS. The only difference is that, in the DBS tests, manual
braking is applied to the subject vehicle. For the first three test
scenarios, the subject vehicle must demonstrate a specific speed
reduction attributable to AEB intervention. The fourth scenario, the
steel trench plate test, is a false positive test, used to evaluate the
propensity of a vehicle's AEB system to activate inappropriately in a
scenario that would not present a safety risk to the vehicle's
occupants. For each of the scenarios, to receive NHTSA's technology
recommendation through NCAP, the vehicle must meet the minimum
specified performance in at least five out of seven valid test trials.
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    \67\ NHTSA. (2015, October). Crash imminent brake system
performance evaluation for the New Car Assessment Program. https://www.regulations.gov. Docket No. NHTSA-2015-0006-0025.
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Lead Vehicle Stopped Tests
    In the NCAP lead vehicle stopped test scenario, the subject vehicle
encounters a stopped lead vehicle on a straight road. The subject
vehicle travels in a straight line, at a constant speed of 40 km/h (25
mph), approaching a stopped lead vehicle in its path. The subject
vehicle's throttle is released within 500 milliseconds (ms) after the
subject vehicle issues an FCW. In the DBS test, the subject vehicle's
brakes are manually applied at a time-to-collision of 1.1 seconds (at a
nominal headway of 12.2 m (40 ft)). To receive credit for CIB, the
subject vehicle speed reduction attributable to CIB intervention must
be >=15.8 km/h (9.8 mph) before the end of the test. To receive credit
for DBS, the subject vehicle must not contact the lead vehicle.
Lead Vehicle Decelerating Tests
    In the lead vehicle decelerating test scenario, the subject vehicle
encounters a lead vehicle slowing with constant deceleration directly
in front of it on a straight road. For this test scenario, the subject
vehicle and lead vehicle are initially both driven at 56.3 km/h (35
mph) with an initial headway of 13.8 m (45.3 ft). The lead vehicle then
decelerates, braking at a constant deceleration of 0.3g in front of the
subject vehicle, after which the subject vehicle throttle is released
within 500 ms after the subject vehicle issues an FCW. In the DBS
testing, the subject vehicle's brakes are applied at a time-to-
collision of 1.4 seconds (at a nominal headway of 9.6 m or 31.5 ft). To
receive credit for passing this test scenario for CIB, the subject
vehicle speed reduction attributable to CIB intervention must be >=16.9
km/h (10.5 mph) before the end of the test. To receive credit for
passing this test for DBS, the subject vehicle must not contact the
lead vehicle.
Lead Vehicle Moving Tests
    In the lead vehicle moving test scenario, the subject vehicle
encounters a slower-moving lead vehicle directly in front of it on a
straight road. For this test scenario, two test conditions are
assessed. For the first test condition, the subject vehicle and lead
vehicle are driven at a constant speed of 40 km/h (25 mph) and 16 km/h
(10 mph), respectively. For the second test condition, the subject and
lead vehicle are driven at a constant speed of 72.4 km/h (45 mph) and
32.2 km/h (20 mph), respectively. In both tests, the subject vehicle
throttle is released within 500 ms after the subject vehicle issues an
FCW. In the DBS tests, the subject vehicle's brakes are applied at a
time-to-collision of 1 second (at a nominal headway of 6.7 meters (22
ft)). To receive credit for passing the first CIB test, the subject
vehicle must not contact the lead vehicle during the test. To receive
credit for passing the second CIB test, the subject vehicle speed
reduction attributable to crash imminent braking intervention must be
>=15.8 km/h (9.8 mph) by the end of the test. To receive credit for
either DBS test, the subject vehicle must not contact the lead vehicle.
Steel Trench Plate Tests
    In the steel trench plate test scenario, the subject vehicle is
driven towards a steel trench plate (2.4 m x 3.7 m x 25.3 mm or 7.9 ft
x 12.1 ft x 1 in) on a straight road at two different speeds: 40 km/h
(25 mph) in one test and 72.4 km/h (45 mph) in the other. The subject
vehicle throttle is released within 500 ms of the warning. For CIB
tests, if no FCW is issued, the throttle is not released until the test
is completed. For DBS tests, the throttle is released such that it is
completely released within 500 ms of 2.1 seconds time-to-collision (at
a nominal distance of 12.3 m (40.4 ft) or 22.3 m (73.2 ft) from the
trench plate, depending on the test speed). The brake pedal is then
applied at 1.1 s time-to-collision. To pass these tests for CIB, the
subject vehicle must not achieve a peak deceleration equal to or
greater than 0.5 g at any time during its approach to the steel trench
plate. To pass the DBS test, the subject vehicle must not experience a
peak deceleration that exceeds 150 percent of the braking experienced
through manual braking alone for the baseline condition at the same
speed.
3. PAEB Test Proposal
    NHTSA conducted research and published several NCAP RFC notices on
the inclusion of PAEB systems. In the 2013 NCAP request for comments
notice, NHTSA noted that PAEB systems capable of addressing both low-
speed front and rear pedestrian impact prevention were already in
production for some vehicle models.\68\ The agency acknowledged that
different technologies were being implemented at the time and different
test procedures were being developed worldwide, although some test
procedure complexities still existed. An additional complexity was the
need for a crash avoidance test dummy that would provide a radar and/or
camera recognition signature that would approximate that of a human and
would be durable enough to withstand any testing impacts. NHTSA
requested comments on methods of addressing and resolving these
complexities.
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    \68\ 78 FR 20597 at 20600.
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    In 2015, the agency announced its plan for several major NCAP
program enhancements, including NHTSA's intention to implement a new 5-
star rating system to convey vehicle safety information in three major
areas--crashworthiness, crash avoidance, and pedestrian protection.\69\
The agency proposed that PAEB be included in the pedestrian protection
rating, along with rear automatic braking and pedestrian
crashworthiness. At the time, NHTSA noted that the agency was still
refining the pedestrian test scenarios for PAEB systems. Specifically,
three different types of apparatus concepts were identified for
transporting a test mannequin in a test run. These included two
overhead gantry-style designs and one moving sled arrangement.
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    \69\ 80 FR 78522 at 78526.
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    In November 2019, NHTSA published a Federal Register notice that
sought comment on draft confirmation test procedures for PAEB, among
other technologies (84 FR 64405).\70\ It included the two most fatal
scenario types: Pedestrian crossing path and

pedestrian along or standing in path. For the crossing path scenario
(S1), the draft included seven specific test procedures (Table 17). The
maximum subject vehicle traveling speed specified was 40 km/h (25 mph)
in all cases.
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    \70\ National Highway Traffic Safety Administration (2019,
April), Pedestrian automatic emergency brake system confirmation
test (working draft). Available at: https://www.regulations.gov/document/NHTSA-2019-0102-0005.
[GRAPHIC] [TIFF OMITTED] TP13JN23.009

    In the first three scenarios (S1a-b-c), a subject vehicle
approaches an adult test mannequin starting on the right-hand side of
the lane of travel and moving toward the left-hand side. The point on
the vehicle at which the subject vehicle will strike the test mannequin
without automatic braking, or overlap, is 25, 50, and 75 percent from
the passenger side of the subject vehicle, respectively. In the fourth
scenario (S1d), the subject vehicle approaches a crossing child test
mannequin running from behind parked vehicles from the right-hand side
of the travel lane toward the left-hand side with the point of impact
at a 50 percent overlap. In the fifth scenario (S1e), the subject
vehicle approaches an adult test mannequin running from the left side