[Federal Register Volume 88, Number 113 (Tuesday, June 13, 2023)]
[Proposed Rules]
[Pages 38632-38736]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-11863]



[[Page 38631]]

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 202-366-9332 before 
coming.
     Fax: 202-493-2251.
    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: 202-366-1810). For 
legal issues: David Jasinski, Office of the Chief Counsel (telephone: 
202-366-2992, fax: 202-366-3820). 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

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    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

[[Page 38634]]

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

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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

[[Page 38636]]

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
------------------------------------------------------------------------
Lifetime Monetized..............              $6,802              $5,518
------------------------------------------------------------------------
                                  Costs
------------------------------------------------------------------------
Lifetime Monetized..............              282.16              282.16
------------------------------------------------------------------------
                              Net Benefits
------------------------------------------------------------------------
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

[[Page 38637]]

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.

[[Page 38638]]

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


[[Page 38639]]

    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

[[Page 38640]]

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


[[Page 38641]]

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

[[Page 38642]]

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

[[Page 38643]]

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,

[[Page 38644]]

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

[[Page 38645]]

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.

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

[[Page 38646]]

    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

[[Page 38647]]

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

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

[[Page 38648]]

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

    \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 
of the travel lane toward the right with a 50 percent overlap point of 
impact.
    The sixth and seventh crossing path scenarios (S1f and S1g) are 
false positive tests. In the sixth scenario, the subject vehicle 
approaches an adult test mannequin, which begins moving from the right-
hand side of the roadway but safely stops short of entering the subject 
vehicle's lane of travel. In the seventh scenario, the adult test 
mannequin also crosses from the right-hand side of the road toward the 
left-hand side, but safely crosses the lane of travel completely. The 
false positive scenarios are used to evaluate the propensity of a PAEB 
system to inappropriately activate in a non-critical driving scenario 
that does not present a safety risk to the subject vehicle occupants or 
pedestrian.
    NHTSA's research test procedures also consisted of three along path 
(S4) test scenarios in which a test mannequin is either standing or 
traveling along the vehicle's lane of travel (Table 18). The maximum 
subject vehicle traveling speed specified was 40 km/h (25 mph) for all 
procedures.
[GRAPHIC] [TIFF OMITTED] TP13JN23.010

    In the first scenario the stationary test mannequin is facing away 
from the vehicle (S4a) and in the second, it is facing toward the 
vehicle (S4b). In third scenario, a subject vehicle encounters an adult 
test mannequin walking in front of the vehicle on the nearside of the 
road away from the vehicle (S4c). In all three procedures, the 
stationary test mannequin is positioned with a 25 percent overlap from 
the passenger side of the vehicle.
    NHTSA used the test procedures to conduct performance evaluations 
of model year 2019 and 2020 vehicles, which were used to support a 
March 9, 2022, request for comments notice proposing to include PAEB 
tests in NCAP.\71\ In addition to PAEB, the RFC notice proposed 
including blind spot detection, blind spot intervention, and lane 
keeping support performance tests in NCAP. It further proposed 
strengthening the existing performance tests for FCW, AEB (CIB and 
DBS), and lane departure warning. It also proposed new rating criteria 
and provided a roadmap for future upgrades to the program.
---------------------------------------------------------------------------

    \71\ 87 FR 13452.
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C. 2016 Voluntary Commitment

    On March 17, 2016, NHTSA and the Insurance Institute for Highway 
Safety (IIHS) announced a commitment by 20 automakers representing more 
than 99 percent of the U.S. light vehicle market to make lower speed 
AEB a standard feature on virtually all new light duty cars and trucks 
with a gross vehicle weight rating (GVWR) of 3,855 kg (8,500 lbs.) or 
less no later than September 1, 2022.\72\ Participating manufacturers 
needed to ensure their vehicles had an FCW system that met NHTSA's FCW 
NCAP requirements for both the lead vehicle moving and lead vehicle 
decelerating performance tests. The

[[Page 38649]]

voluntary commitment does not include meeting NHTSA's FCW NCAP 
requirements for the stopped lead vehicle scenario. The voluntary 
commitment includes automatic braking system performance (CIB only) 
able to achieve a specified average speed reduction over five repeated 
trials when assessed in a stationary lead vehicle test conducted at 
either 19 or 40 km/h (12 or 25 mph). To satisfy the performance 
specifications in the voluntary commitment, the vehicle would need to 
achieve a speed reduction of at least 16 km/h (10 mph) in either lead 
vehicle stopped test, or a speed reduction of 8 km/h (5 mph) in both 
tests. Participating automakers also committed to making the technology 
standard on virtually all trucks with a GVWR between 3,856 kg (8,501 
lbs.) and 4,536 kg (10,000 lbs.) no later than September 1, 2025.
---------------------------------------------------------------------------

    \72\ Audi, BMW, FCA US LLC, Ford, General Motors, Honda, 
Hyundai, Jaguar Land Rover, Kia, Maserati, Mazda, Mercedes-Benz, 
Mitsubishi Motors, Nissan, Porsche, Subaru, Tesla Motors Inc., 
Toyota, Volkswagen, and Volvo Car USA--representing more than 99 
percent of the U.S. new light vehicle market.
---------------------------------------------------------------------------

D. Response To Petition for Rulemaking

    In 2017, NHTSA denied a petition for rulemaking from Consumer 
Watchdog, Center for Automotive Safety, and Public Citizen which 
requested that NHTSA initiate a rulemaking to require FCW, CIB, and DBS 
on all light vehicles.\73\ NHTSA denied the petition after deciding 
that NCAP, the voluntary commitment, and the consumer information 
programs of various organizations would produce benefits substantially 
similar to those that would eventually result from the petitioner's 
requested rulemaking. Accordingly, the agency did not find evidence of 
a market failure warranting initiation of the requested rulemaking.\74\ 
NHTSA further stated that the non-regulatory activities being 
undertaken at the time would make AEB standard on new light vehicles 
faster than could be achieved through a regulatory process and would 
thus make AEB standard equipment earlier, with its associated safety 
benefits. NHTSA stated that it would monitor vehicle performance in 
NCAP and the industry's voluntary commitment, and initiate rulemaking 
if the need arose.
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    \73\ 82 FR 8391 (January 25, 2017).
    \74\ Section 1(b) of E.O. 12866 requires agencies to assess the 
failures of private markets to address the problem identified by the 
agency.
---------------------------------------------------------------------------

V. NHTSA's Decision To Require AEB

A. This Proposed Rule Is Needed To Address Urgent Safety Problems

    NHTSA announced its intention to propose an FMVSS for AEB light 
vehicles in the Spring 2021 Unified Regulatory Agenda.\75\ In making 
the decision to initiate this rulemaking, NHTSA recognized that the 
non-regulatory measures leading up to this NPRM had been key to an 
increased and more rapid fleet penetration of AEB technology but 
decided that rulemaking would best address the rise in motor vehicle 
fatalities. In addition, NHTSA found that AEB could perform effectively 
at higher speeds than the systems included in the voluntary agreement 
and NCAP and that PAEB in darkness has become technologically possible.
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    \75\ https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202104&RIN=2127-AM37.
---------------------------------------------------------------------------

    NHTSA initiated this rulemaking to reduce the frequency of rear-end 
crashes, which is the most prevalent vehicle crash type, and to target 
one of the most concerning and urgent traffic safety problems facing 
the U.S. today--the rapidly increasing numbers of pedestrian fatalities 
and injuries. Rear-end crashes are very common, although most are not 
deadly. Nevertheless, approximately 2,000 people die in rear-end 
crashes each year, making up 5 to 7 percent of total crash fatalities. 
Pedestrian crashes are deadly and have been increasing in recent years. 
They tend to happen at night and at higher speeds. About half of fatal 
pedestrian crashes happen on roads with a speed limit of 40 mph or 
lower and half on roads with a speed limit of 45 mph and higher.
    The non-regulatory approaches of the past were instrumental in 
developing AEB and encouraging manufacturers to include and consumers 
to purchase AEB in most passenger vehicles sold today. With AEB sensors 
and other hardware installed in the fleet as a result of NCAP and the 
voluntary commitment, regulatory costs to equip new vehicles are 
reduced. However, an FMVSS is needed to compel technological 
improvement of AEB systems, and to ensure that every vehicle will be 
equipped with a proven countermeasure that can drastically reduce the 
frequency and severity of rear-end crashes and the safety risks posed 
to pedestrians. NHTSA is aware of data and other information indicating 
potential opportunities for AEB improvement. A recent IIHS study of 
2009-2016 crash data from 23 States suggested that the increasing 
effectiveness of AEB technology in certain crash situations is changing 
rear-end crash scenarios.\76\ IIHS's study identified rear-end crashes 
in which striking vehicles equipped with AEB were over-represented 
compared to those without AEB. For instance, IIHS found that striking 
vehicles involved in the following rear-end crashes were more likely to 
have AEB: (1) where the striking vehicle was turning relative to when 
it was moving straight; (2) when the struck vehicle was turning or 
changing lanes relative to when it was slowing or stopped; (3) when the 
struck vehicle was not a passenger vehicle or was a special use vehicle 
relative to a passenger car; (4) on snowy or icy roads; or (5) on roads 
with speed limits of 70 mph relative to those with 64 to 72.4 km/h (40 
to 45 mph) speed limits. Overall, the study found that 25.3 percent of 
crashes where the striking vehicle was equipped with AEB had at least 
one of these over-represented characteristics, compared with 15.9 
percent of impacts by vehicles that were not equipped with AEB. IIHS 
found that in 2016, nearly 300,000 (15 percent) of the police reported 
two-vehicle rear-end crashes involved one of the rear-end crashes 
mentioned above.
---------------------------------------------------------------------------

    \76\ Cicchino, J.B. & Zuby, D.S. (2019, August), Characteristics 
of rear-end crashes involving passenger vehicles with automatic 
emergency braking, Traffic Injury Prevention, 2019, VOL. 20, NO. S1, 
S112-S118 https://doi.org/10.1080/15389588.2019.1576172.
---------------------------------------------------------------------------

    These results suggest that the metrics used to evaluate the 
performance of AEB systems by NHTSA's NCAP, the voluntary industry 
commitment, and other consumer information programs have facilitated 
the development of AEB systems that reduce the crashes they were 
designed to address. However, the results also indicate that AEB 
systems have not yet provided their full crash reduction potential. 
While they are effective at addressing some of the lower speed rear-end 
crashes, they are less effective at fully addressing the safety need.
    These data also indicate the potential of AEB to reduce fatal 
crashes, especially if test speeds were increased. Accordingly, NHTSA 
has issued this NPRM to drive AEB performance to maximize safety 
benefits, assess practicability limits, and ensure that AEB technology 
is incorporated in all vehicles to the extent possible. This NPRM is 
issued to reach farther than NCAP to expand the availability of AEB 
technologies to all vehicles--not just to those whose manufacturers 
were incentivized to add such systems or whose purchasers were 
interested in purchasing them. By ensuring the universal implementation 
of AEB, this NPRM would best achieve equity in the safety provided 
across vehicles and the safety provided to the communities on whose 
roads they operate.
    This NPRM would improve the capability of AEB systems beyond that 
of the low-speed AEB systems contemplated by the voluntary commitment, 
increasing safety benefits. The NPRM also would require PAEB,

[[Page 38650]]

while the voluntary commitment does not address PAEB. Requiring AEB 
systems under an FMVSS would ensure that manufacturers design and 
produce vehicles that provide at least the minimum level of safety 
mandated by the standard or face consequences for not doing so, 
including recalling the vehicle and remedying the noncompliance free of 
charge. These positive outcomes could not be achieved by a voluntary 
commitment alone.
    Further, this NPRM responds to Congress's directive that AEB be 
required on all passenger vehicles. On November 15, 2021, President 
Biden signed the Bipartisan Infrastructure Law, codified as the 
Infrastructure Investment and Jobs Act.\77\ Section 24208(a) of BIL 
added 49 U.S.C. 30129, directing the Secretary of Transportation to 
promulgate a rule to establish minimum performance standards with 
respect to crash avoidance technology and to require that all passenger 
motor vehicles for sale in the United States be equipped with a forward 
collision warning system and an automatic emergency braking system.\78\ 
The FCW and AEB system is required to alert the driver if the vehicle 
is closing its distance too quickly to a vehicle ahead or to an object 
in the path of travel ahead and a collision is imminent, and to 
automatically apply the brakes if the driver fails to do so.
---------------------------------------------------------------------------

    \77\ Public Law 117-58, 24208 (Nov. 15, 2021).
    \78\ Section 24208 also directs DOT to require a lane departure 
warning and lane-keeping assist system that warns the driver to 
maintain the lane of travel; and corrects the course of travel if 
the driver fails to do so.
---------------------------------------------------------------------------

    BIL requires that ``all passenger motor vehicles'' be equipped with 
AEB and FCW. This NPRM would require AEB and FCW on all passenger cars 
and multipurpose passenger vehicles, trucks, and buses with a GVWR of 
10,000 lbs. or less. NHTSA believes that the scope of this NPRM 
includes all vehicles required be equipped with AEB by section 24208 of 
the IIJA.
    BIL further requires that an FCW system alert the driver if there 
is a ``vehicle ahead or an object in the path of travel'' if a 
collision is imminent. Accordingly, NHTSA has defined an AEB system as 
one that detects an imminent collision with a vehicle or with an 
object. NHTSA does not read this provision as mandating a particular 
level of performance regarding the detection of vehicles and objects. 
More specifically, NHTSA does not interpret this provision to require 
passenger vehicles to detect and respond to imminent collisions with 
all vehicles or all objects in all scenarios. Such a requirement would 
be unreasonable given the wide array of harmless objects that drivers 
could encounter on the roadway that do not present safety risks. NHTSA 
also does not interpret section 24208 to mandate AEB performance to 
avoid any specific objects or to mandate PAEB.
    Instead, NHTSA interprets section 24208 as broadly requiring AEB 
capable of detecting and responding to vehicles and objects while 
leaving to NHTSA the discretion to promulgate specific performance 
requirements. Following this interpretation, NHTSA's proposal, if 
implemented, would require light vehicles to be equipped with FCW and 
automatic emergency braking, and the proposal defines AEB as a system 
that detects an imminent collision with vehicles, objects, and road 
users in or near the path of a vehicle and automatically controls the 
vehicle's service brakes to avoid or mitigate the collision.
    NHTSA has authority and discretion to promulgate requirements that 
go beyond those contemplated under Section 24208. Pursuant to its 
authority at 49 U.S.C. 30111, NHTSA is proposing that all light 
passenger vehicles be required to have PAEB.

B. Stakeholder Interest in AEB

1. National Transportation Safety Board Recommendations
    This NPRM is responsive to several National Transportation Safety 
Board (NTSB) recommendations. In May 2015, the NTSB issued a special 
investigation report, ``The Use of Forward Collision Avoidance Systems 
to Prevent and Mitigate Rear-End Crashes.'' \79\ The report detailed 
nine crash investigations involving passenger or commercial vehicles 
striking the rear of another vehicle, and concluded that collision 
warning systems, particularly when paired with active braking, could 
significantly reduce the frequency and severity of rear-end crashes. As 
a result, the NTSB issued several safety recommendations to NHTSA, 
including the following:
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    \79\ https://www.ntsb.gov/safety/safety-studies/Documents/SIR1501.pdf.
---------------------------------------------------------------------------

     H-15-04: Develop and apply testing protocols to assess the 
performance of forward collision avoidance systems in passenger 
vehicles at various velocities, including high speed and high velocity-
differential.
    In September 2018, the NTSB issued another special investigation 
report, ``Pedestrian Safety.'' \80\ This report examined the past 10 
years of pedestrian crash data, described NTSB pedestrian safety 
investigations, and summarized issues raised in a public forum. As a 
result, the NTSB issued several safety recommendations to NHTSA, 
including the following:
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    \80\ https://www.ntsb.gov/safety/safety-studies/Documents/SIR1803.pdf.
---------------------------------------------------------------------------

     H-18-41: Develop performance test criteria for vehicle 
designs that reduce injuries to pedestrians.
     H-18-42: Develop performance test criteria for 
manufacturers to use in evaluating the extent to which automated 
pedestrian safety systems in light vehicles will prevent or mitigate 
pedestrian injury.
2. Consumer Information Programs in the United States
    In the United States, in addition to NHTSA's NCAP, the Insurance 
Institute for Highway Safety also tests AEB systems in vehicles for the 
purpose of informing consumers about their performance. Both programs 
test AEB systems in response to a stationary lead vehicle test device, 
but IIHS only performs tests to assess crash imminent braking system 
performance, while NCAP AEB evaluations also test DBS responses and 
assess system performance for both slower-moving and decelerating lead 
vehicle scenarios. NCAP also tests for false positive AEB activation by 
having subject vehicles drive over a steel trench plate. NCAP provides 
pass/fail results based on speed reduction and crash avoidance in DBS 
tests attributed to AEB, while IIHS awards points based only on speed 
reduction.\81\ Both programs are considering upgrades to their AEB 
performance tests. On March 9, 2022, NHTSA issued a request for 
comments notice proposing increased test speeds in its DBS and CIB test 
protocols. On May 5, 2022, IIHS announced its intention to test six 
vehicles equipped with AEB at higher speeds, up to 72.4 km/h (45 mph), 
to better align with reported crashes.\82\
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    \81\ The March 9, 2022, request for comments notice also asks 
for public comment on NHTSA's plan to develop a future rating system 
for new vehicles based on the availability and performance of all 
the NCAP-recommended crash avoidance technologies. 87 FR 13452.
    \82\ https://www.iihs.org/news/detail/iihs-eyes-higher-speed-test-for-automatic-emergency-braking.
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    IIHS further conducts PAEB tests in two scenarios like those 
proposed in the NPRM. In the first scenario, an articulated test 
mannequin crosses the subject vehicle's path; this condition is tested 
with both the articulated child surrogate (Perpendicular Child) and the 
articulated adult surrogate (Perpendicular Adult). In the second 
scenario, an adult test mannequin without articulation is standing in a

[[Page 38651]]

vehicle's path, offset 25 percent from center (Parallel Adult). Both 
test scenarios are conducted during daylight conditions. Points are 
awarded in the IIHS test based on vehicle speed reduction.
    Other consumer information groups have also invested effort into 
supplying customers with information regarding AEB. Since 2016, 
Consumer Reports has been awarding ``bonus'' points to its overall 
score for vehicles that come equipped with AEB and FCW as standard 
features across all trim levels of a model.\83\
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    \83\ https://www.consumerreports.org/car-safety/where-automakers-stand-on-automatic-emergency-braking-pledge/.
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3. Petition for Rulemaking on PAEB Performance in Dark Conditions
    On March 22, 2022, IIHS and the Highway Loss Data Institute 
petitioned NHTSA to require, through rulemaking, that passenger 
vehicles be equipped with AEB that responds to pedestrians in all light 
conditions. The petitioners stated that research from IIHS estimates 
that PAEB systems reduce pedestrian crash risk by an estimated 32 to 33 
percent in daylight or dark conditions with street lighting but does 
not reduce pedestrian crash risk in the dark without street lighting. 
The petitioners stated that over a third of pedestrian deaths occur in 
dark, unlit conditions, and that requiring PAEB systems that function 
in those conditions will lead to a greater reduction in fatalities than 
only requiring those systems that function in daylight.
    When NHTSA received the petition from IIHS, the agency had already 
announced in the Fall 2021 Unified Agenda of Regulatory and 
Deregulatory Actions \84\ that it had initiated rulemaking on PAEB. The 
agency announced that it would issue a proposal to require and/or 
standardize performance for light vehicle AEB, including PAEB. NHTSA's 
Agenda entry further announced that this rulemaking would set 
performance requirements for AEB systems and would specify a test 
procedure under which compliance with those requirements would be 
measured. Given this context, NHTSA denied the petition as moot because 
NHTSA had already commenced rulemaking on the requested action and was, 
and remains, deeply immersed in developing the rule. Although NHTSA has 
denied the petition, NHTSA has considered its points as suggestions for 
this rulemaking. A copy of the petition has been placed in the docket 
for this rulemaking.
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    \84\ https://www.reginfo.gov/public/do/eAgendaMain; See RIN 
2127-AM37, titled, ``Light Vehicle Automatic Emergency Braking (AEB) 
with Pedestrian AEB.''
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C. Key Findings Underlying This Proposal

1. Impact Speed Is Key To Improving AEB's Mitigation of Fatalities and 
Injuries
    As described in the section II of this NPRM, 79 percent of 
property-damage-only crashes, 73 percent of injuries, and 60 percent of 
fatalities in rear-end crashes involving light vehicles occur on roads 
where the posted speed limit is 60 mph (97 km/h) or less. However, the 
majority of those crashes are skewed towards the higher end of that 
range. Only 3 percent of fatalities, 9 percent of injuries, and 12 
percent of property-damage-only crashes occur at posted speeds below 30 
mph (48 km/h). NHTSA believes that most of the safety need exists at 
speeds greater than 30 mph (48 km/h). In light of these data, this NPRM 
seeks to address a safety need at a speed well above that found in the 
voluntary commitment, which has a maximum test speed of 40 km/h (25 
mph). The data show that speeds higher than those proposed in the 2022 
NCAP request for comments notice \85\ (with a maximum testing speed of 
80 km/h (50 mph)) are also required to address the safety need.\86\ In 
fact, the data demonstrate the safety need for AEB systems to activate 
at as high a speed as can practicably be achieved.
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    \85\ 87 FR 13452.
    \86\ In 2019, 67 percent of fatalities within the target 
population occur where the posted speeds are above 50 mph, and 29 
percent of the fatalities occur at posted speeds of 55 mph and 60 
mph.
---------------------------------------------------------------------------

2. Darkness Performance of PAEB Is Highly Important
    Out of the 4,069 pedestrian fatalities in 2019 resulting from being 
struck by the front of a light vehicle, about 77 percent occurred in 
dark conditions and about 50 percent of all pedestrian fatalities 
occurred at posted speeds of 40 mph (64 km/h) or less. Forty percent of 
all pedestrian injuries, regardless of how a pedestrian is struck, 
occur in dark conditions and 57 percent of them occur at posted speeds 
of 40 mph (64 km/h) or less. Based on these data, the agency 
tentatively concludes that performance testing under various lighting 
conditions and at higher speeds is necessary.
    During 2020 agency research testing using model year 2019 and 2020 
vehicles, observed AEB performance was not consistent for some of the 
proposed lighting conditions and speeds. During PAEB testing, 5 out of 
11 vehicles avoided collision in at least one test at speeds up to 60 
km/h (37.3 mph) in daylight when an adult pedestrian test mannequin 
crossed the path of the vehicle from the right; absent PAEB 
intervention, the front middle section of the vehicle would have hit 
the test mannequin. For the same scenario, 5 vehicles out of 11 avoided 
impact with the test mannequin in at least one test at speeds up to 40 
km/h (25 mph) when testing using the vehicle's lower beam headlamps in 
dark conditions. Only 1 of 11 vehicles could consistently avoid impact 
in every test trial in each of the daylight and dark lower beam 
headlamp conditions at these speeds.
    For tests involving a stationary pedestrian test mannequin situated 
toward the right side of the road, but within the path of the vehicle, 
3 vehicles out of 11 consistently avoided impact at speeds up to 50 km/
h (31.1 mph) in daylight conditions, and one avoided impact in five out 
of six tests at 60 km/h (37 mph). In dark conditions, using only the 
lower beam headlamps, one vehicle avoided collision at all speeds up to 
50 km/h (31.1 mph) and in four out of five tests at 55 km/h (34.2 mph). 
However, other tested vehicles contacted the test mannequin at all 
speeds above 16 km/h (10 mph) in the same darkness condition.
    NHTSA has tentatively concluded that the performance achieved by 
the better performing vehicles in dark lighting conditions can be 
achieved by all vehicles given an adequate phase-in period. This is 
consistent with recent testing performed by IIHS, which found that 
existing systems can perform in darkness conditions regardless of their 
IIHS headlamp ratings.\87\ The agency tentatively concludes that AEB 
system performance is improving, and the latest AEB systems are already 
able to perform much better than previous systems. Concurrent with the 
development of this proposed rule, NHTSA performed PAEB testing on 
model year 2021 and 2022 vehicles using the proposed performance 
requirements and test procedures. The results of this testing are 
detailed in the PAEB report docketed with this proposed rule.
---------------------------------------------------------------------------

    \87\ IIHS dark light press release: https://www.iihs.org/news/detail/pedestrian-crash-avoidance-systems-cut-crashes--but-not-in-the-dark.
---------------------------------------------------------------------------

3. NHTSA's 2020 Research on Lead Vehicle AEB and PAEB Performance Show 
the Practicability of Higher Speed Tests
    In 2020, NHTSA conducted lead vehicle AEB and PAEB performance 
tests on 11 model year 2019 and 2020 vehicles from 10 vehicle 
manufacturers.

[[Page 38652]]

This work was done to support the agency's March 9, 2022 request for 
comments notice proposing to upgrade NCAP, as well as to assist in the 
development of this NPRM.
a. Lead Vehicle AEB Performance Tests
    To evaluate lead vehicle AEB performance at higher speeds, the 
agency performed CIB tests in accordance with NCAP's CIB test 
procedures,\88\ but repeated the lead vehicle stopped and lead vehicle 
decelerating test scenarios using an expanded set of input conditions 
to assess how specific test procedures changes, such as increasing 
speed or deceleration magnitude, would affect the vehicle's CIB 
performance. NHTSA placed test reports detailing the results in the 
docket of the March 9, 2022, NCAP request for comments notice on the 
proposed updates.\89\
---------------------------------------------------------------------------

    \88\ www.regulations.gov. NHTSA Docket No. NHTSA-2015-0006-0025.
    \89\ www.regulations.gov. NHTSA Docket No. NHTSA-2021-0002-0002. 
``Final MY2019/MY2020 Research Reports for Pedestrian Automatic 
Emergency Braking, High-Speed Crash Imminent Braking, Blind Spot 
Warning, and Blind Spot Intervention Testing.'' There are 11 test 
reports w/the following title for each vehicle name: ``Crash 
Imminent Braking System Research Test.''
---------------------------------------------------------------------------

    For the NCAP CIB lead vehicle stopped test scenario, NHTSA 
conducted tests at incremental vehicle speeds from 40 to 72.4 km/h (25 
to 45 mph). The results showed that the tested vehicle CIB systems 
exceeded the performance established in consumer programs, such as 
model year 2022 NCAP and IIHS. Three vehicles were able to demonstrate 
no contact with the lead vehicle at speeds up to 72.4 km/h (45 mph), 
and the remaining eight vehicles had an average speed reduction of 37.7 
km/h (23.4 mph) when tested at this speed.\90\ One vehicle avoided 
contact in all tests and at speeds up to 72.4 km/h (45 mph), for a 
total of 27 out of 27 tests without contact.
---------------------------------------------------------------------------

    \90\ Two vehicles were able to avoid contact in five out of five 
tests conducted at 72.4 km/h (45 mph). The third vehicle avoided 
contact in one out of five tests conducted at 72.4 km/h (45 mph).
---------------------------------------------------------------------------

    NHTSA also conducted CIB lead vehicle decelerating tests as a part 
of NHTSA's 2020 research study. When the test conditions were modified 
such that the lead vehicle decelerated at 0.5g, rather than 0.3g as 
specified in NHTSA's CIB NCAP test procedure, eight vehicles 
demonstrated the ability to avoid contact with the lead vehicle in at 
least one test and three vehicles avoided contact in all tests despite 
having less time to avoid the crash. Similarly, when the speed of the 
subject vehicle and lead vehicle was increased to 72.4 km/h (45 mph), 
nine vehicles demonstrated the ability to avoid contact with the lead 
vehicle in at least one test while four vehicles avoided contact in all 
tests. One vehicle was able to avoid contact in all lead vehicle 
decelerating tests, including both increased speeds and increased lead 
vehicle deceleration.
    Although NHTSA did not perform higher speed evaluations for the 
slower-moving lead vehicle test scenario as part of its CIB study, 
NHTSA believes that it is reasonable and appropriate for this NPRM to 
propose raising the subject vehicle speed above that specified 
currently in NCAP's test to ensure improved AEB performance. NHTSA also 
did not conduct DBS testing in its characterization study to evaluate 
AEB system performance capabilities. However, the CIB and DBS test 
procedures proposed in this NPRM use the same test scenarios. 
Differences exist only with respect to the use of subject vehicle 
manual brake application and maximum test speeds. NHTSA constructed its 
2020 research program using CIB to demonstrate the practicability of 
testing at higher speeds with a no-contact requirement. In past 
testing, DBS performance has typically been as good as if not better 
than CIB.
    Concurrent with the development of this proposed rule, NHTSA 
performed lead vehicle AEB testing on model year 2021 and 2022 vehicles 
using the proposed performance requirements and test procedures. The 
results of that testing provide additional support to the tentative 
conclusion that the test conditions, parameters, and procedures are 
practical to conduct and that the proposed requirements are practical 
for manufacturers to achieve. The results of this testing are detailed 
in the lead vehicle AEB report docketed with this proposed rule. The 12 
model year 2021 and 2022 vehicles were selected to provide a balance of 
anticipated market penetration (using 2021 sales data) and a mix of 
vehicle types, including internal combustion engine vehicles and 
electric vehicles. Tests enabled the agency to refine the test 
procedures and validate test execution within the proposed tolerances.
b. PAEB Daytime Performance Tests
    NHTSA selected the same 11 model year 2019 and 2020 vehicles used 
in the CIB testing to assess the performance of current PAEB systems. 
NHTSA issued test reports detailing the results in support of the March 
9, 2022, NCAP request for comments notice.\91\
---------------------------------------------------------------------------

    \91\ See Docket No. NHTSA-2021-0002-0002. There are embedded 
reports titled, ``PEDESTRIAN AUTOMATIC EMERGENCY BRAKING SYSTEM 
RESEARCH TEST'' for each of the 11 vehicle make/models.
---------------------------------------------------------------------------

    As shown in Table 19, NHTSA used its 2019 draft PAEB research test 
procedures, but increased the subject vehicle speed for specific test 
conditions.\92\ Additionally, NHTSA used articulating test mannequins, 
as used in Euro NCAP, instead of the posable mannequins specified in 
the draft test procedure.\93\
---------------------------------------------------------------------------

    \92\ 84 FR 64405 (Nov. 21, 2019). www.regulations.gov, NHTSA 
Docket No. NHTSA-2019-0102-0005. Note, in this document, the PAEB 
test procedures were called ``Pedestrian Automatic Emergency Brake 
System Confirmation Tests.'' NHTSA increased test speeds for the 
S1b, S1d, S1e, S4a, and S4c from NHTSA's draft test procedure.
    \93\ https://cdn.euroncap.com/media/41769/euro-ncap-pedestrian-testing-protocol-v85.201811091256001913.pdf.

                                             Table 19--Matrix of the Daytime PAEB NHTSA 2020 Research Tests
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                          Crossing path
                                                     Along path
--------------------------------------------------------------------------------------------------------------------------------------------------------
Test Mann...............................               Adult                  Child       Adult            Adult
                                                       Adult
                                         ---------------------------------------------------------------------------------------------------------------
Motion..................................              Walking
                                                 Running
                                                 Walking
                                                  Fixed          Walking
                                         ---------------------------------------------------------------------------------------------------------------
Direction...............................               Right                  Right,       Left      Right      Right      Facing     Facing   Away from
                                                                            Obstructed                                      Away     Vehicle    Vehicle
                                         ---------------------------------------------------------------------------------------------------------------
Test Mann. Speed........................               5 km/h                 5 km/h      8 km/h     5 km/h     5 km/h     0 km/h     0 km/h     5 km/h


[[Page 38653]]


                                        Table 19--Matrix of the Daytime PAEB NHTSA 2020 Research Tests--Continued
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                          Crossing path
                                                     Along path
--------------------------------------------------------------------------------------------------------------------------------------------------------
Overlap.................................     25%        50%        75%         50%         50%       Stops     Crosses/     25%        25%        25%
                                                                                                     Before     Clears
                                                                                                    Vehicle    Vehicle
                                                                                                      Path       Path
--------------------------------------------------------------------------------------------------------------------------------------------------------
Scenario                                        S1a        S1b        S1c          S1d        S1e        S1f        S1g        S4a        S4b        S4c
--------------------------------------------------------------------------------------------------------------------------------------------------------
Subject Vehicle Speed (km/h)............         16         16         16           16         40         40         40         16         16         16
                                                 40         20         40           20         50  .........  .........         40         40         40
                                          .........         30  .........           30         60  .........  .........         50  .........         50
                                          .........         40  .........           40  .........  .........  .........         60  .........         60
                                          .........         50  .........           50  .........  .........  .........         70  .........         70
                                          .........         60  .........           60  .........  .........  .........         80  .........         80
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The maximum test speeds for the crossing path and along path 
scenarios were 60 km/h (37.5 mph) and 80 km/h (50 mph), respectively. 
These maximum speeds were consistent with Euro NCAP's AEB Vulnerable 
Road User Protection protocol published at the time of testing.\94\
---------------------------------------------------------------------------

    \94\ European New Car Assessment Programme (Euro NCAP). (2019, 
July). TEST PROTOCOL--AEB VRU systems 3.0.2.
---------------------------------------------------------------------------

    The results demonstrated that several vehicles avoided contact with 
the test mannequin in nearly all tests conducted, including at speeds 
up to 60 km/h (37.5 mph) in the 50 percent overlap test (S1b). The most 
challenging crossing path test condition was the running child from 
behind parked vehicle condition (S1d); however, one vehicle was able to 
detect and avoid contact with the test mannequin at all subject vehicle 
speeds up to 60 km/h (37.5 mph). Similarly, in the crossing adult 
pedestrian running from the left side test condition (S1e), the testing 
demonstrated that at least one vehicle did not collide with the test 
mannequin in all tests conducted at speeds up to 60 km/h (37.5 
mph).\95\ The walking test mannequin stopping prior to entering the 
travel lane test condition (S1f) was the most challenging for vehicles 
to predict and not unnecessarily activate PAEB. The other false 
positive test, where a crossing adult test mannequin walks from the 
nearside and clears the vehicle's path (S1g), resulted in fewer 
instances of automatic braking.
---------------------------------------------------------------------------

    \95\ At the 60 km/h (37.5 mph) test speed, the vehicle achieved 
no contact in four out of five tests conducted.
---------------------------------------------------------------------------

    In the test with the stationary pedestrian facing away from the 
subject vehicle (S4a), NHTSA's research testing showed that several 
vehicles were able to repeatedly avoid impacting the test mannequin at 
speeds of 50 km/h (31 mph) and 60 km/h (37.5 mph). However, vehicles 
were not able to avoid impact at the highest test speed of 80 km/h (50 
mph). In the scenario where the subject vehicle encounters an adult 
pedestrian walking away from the vehicle (S4c), two vehicles were able 
to avoid contact with the test mannequin in tests at speeds up to 65 
km/h (40.3 mph) during each test performed at that speed.
c. PAEB Darkness Performance Tests
    NHTSA conducted additional PAEB tests under dark lighting 
conditions using vehicle lower and upper beam headlamps. The tests used 
the same test scenarios and conditions as NHTSA's 2019 draft research 
test procedures and the same 11 vehicles tested for CIB and daylight 
PAEB performance. Tests were conducted first with the test mannequin 
illuminated only by the vehicle's lower beam headlamps and then by the 
upper beam headlamps. The area where the test mannequin was located was 
not provided any additional light source.

                     Table 20--Matrix of the Dark Lighting PAEB NHTSA 2020 Research Tests *
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
                                                   Crossing path
                                            Along path
----------------------------------------------------------------------------------------------------------------
Test Mann.......................       Adult           Child           Adult           Adult           Adult
                                 -------------------------------------------------------------------------------
Motion..........................      Walking                 Running                  Fixed          Walking
                                 -------------------------------------------------------------------------------
Direction.......................       Right          Right,           Left         Facing Away      Away from
                                                    Obstructed                                        Vehicle
                                 -------------------------------------------------------------------------------
Test Mann. Speed................      5 km/h          5 km/h          8 km/h          0 km/h          5 km/h
                                 -------------------------------------------------------------------------------
Overlap.........................        50%             50%             50%             25%             25%
----------------------------------------------------------------------------------------------------------------
Scenario                                     S1b             S1d             S1e             S4a             S4c
----------------------------------------------------------------------------------------------------------------
Subject Vehicle Speed (km/h)....              16              16              40              16              16
                                              20              20              50              40              40
                                              30              30              60              50              50
                                              40              40  ..............              60              60
                                              50              50  ..............              70              70
                                              60              60  ..............              80              80
----------------------------------------------------------------------------------------------------------------
* Tests were separately conducted with the vehicle lower and upper beam headlamps activated.


[[Page 38654]]

    NHTSA's testing showed that tests conducted with upper beam 
headlamps generally resulted in greater braking and less contact with 
the test mannequin than identical tests conducted with lower beam 
headlamps in the S1b test condition. The maximum speed at which at 
least one vehicle avoided contact in all trials with the test mannequin 
was 60 km/h (37.3 mph) for the upper beam condition, compared to 50 km/
h (31.1 mph) for the lower beam condition.
    NHTSA observed that many of the model year 2019 and 2020 vehicles 
experienced difficulties or inconsistent performance in the crossing 
child pedestrian running from behind parked vehicles scenario (S1d). 
Many vehicle contacts with the test mannequin did not include any AEB 
system activation. Additionally, many of the tests in the crossing 
adult pedestrian running from the left side test condition (S1e) were 
not conducted due to the lack of PAEB activation at lower speeds. For 
example, in the lower beam tests at 40 km/h (25 mph), 8 of the 11 
vehicles could not avoid test mannequin contact. Vehicle performance in 
the upper beam headlamp tests were only marginally better for this test 
condition.
    In the along path research tests (S4a), one vehicle was able to 
avoid test mannequin contact for all vehicle test speeds up to 60 km/h 
(37.5 mph) using the upper beam headlamps and at speeds up to 55 km/h 
(34.2 mph) using the lower beam headlamps. However, many other vehicles 
were not tested above 40 km/h (25 mph) due to contact with the test 
mannequin.
    Likewise, in the scenario in which the subject vehicle encounters 
an adult pedestrian standing facing away from the vehicle (S4c), many 
vehicles were not tested above 40 km/h (25 mph) due to repeated contact 
with the test mannequin. In the lower beam headlamp tests, two vehicles 
were able to avoid contact with the test mannequin in tests at speeds 
up to 60 km/h (37.5 mph), and one was able to do so during each test 
performed. In the upper beam headlamp tests, one vehicle was able to 
avoid contact with the test mannequin during each test performed at all 
tested speeds up to 50 km/h (31.1 mph).
d. PAEB Darkness Performance Tests With Overhead Lighting
    To study potential performance differences attributable to the use 
of overhead lights during dark conditions, NHTSA performed several of 
the PAEB test scenarios at two test speeds, 16 km/h (10 mph) and 40 km/
h (25 mph), using two model year 2020 vehicles.\96\ This study was 
performed using the vehicles' lower beams under dark conditions with 
overhead lights. In this testing, the agency observed only slightly 
better PAEB performance in dark lighting conditions with overhead 
lights than in dark lighting conditions without overhead lights.
---------------------------------------------------------------------------

    \96\ Specifically, NHTSA performed overhead lighting tests using 
scenarios S1b, S1d, and S1e and S4a and S4c.
---------------------------------------------------------------------------

4. This Proposed Standard Complements Other NHTSA Actions
    This NPRM is part of NHTSA's multi-pronged approach to enhance 
vehicle performance against pedestrian injury and counter the rising 
numbers of pedestrian fatalities and injuries. This proposal would 
require the installation of PAEB technologies that warn about and 
respond to an imminent collision with a pedestrian at higher speeds 
than PAEB systems on the market today.
    This proposal would complement a rulemaking proposal under 
development that would require that passenger vehicle hoods mitigate 
the risk of serious or fatal child and adult head injury in pedestrian 
crashes.\97\ When new vehicles are equipped with PAEB, fewer 
pedestrians will be struck. For impacts that cannot be avoided due to 
high closing speed of the vehicle, the automatic braking provided by 
PAEB will lower the vehicle's speed at impact. Lowering the speed of 
pedestrian impact and strengthening pedestrian protection provided by 
vehicle hoods would be complementary actions, resulting in 
complementary benefits of the two proposed rules. Furthermore, NHTSA 
has announced plans to propose a crashworthiness pedestrian protection 
testing program in NCAP. This pedestrian protection program would 
incorporate three crashworthiness tests (i.e., head-to-hood, upper leg-
to-hood leading edge, and lower leg-to-bumper).\98\
---------------------------------------------------------------------------

    \97\ Unified Agenda of Regulatory and Deregulatory Actions, 
Regulation Identifier Number (RIN) 2127-AK98, ``Pedestrian Safety 
Global Technical Regulation.''
    \98\ 87 FR 13452, March 9, 2022.
---------------------------------------------------------------------------

    On February 22, 2022, NHTSA published a final rule amending NHTSA's 
lighting standard to allow adaptive driving beam headlamps.\99\ These 
headlighting systems incorporate an advanced type of headlamp beam 
switching that can provide a variable upper beam sculpted so that it 
provides more light on the roadway ahead without creating glare for the 
drivers of oncoming or preceding vehicles. Adaptive driving beam 
headlighting systems also have the potential to provide safety benefits 
in preventing collisions with pedestrians.
---------------------------------------------------------------------------

    \99\ RIN 2127-AL83.
---------------------------------------------------------------------------

VI. Proposal To Require Automatic Emergency Braking

    This NPRM proposes a new FMVSS to require AEB systems on light 
vehicles that are capable of reducing the frequency and severity both 
rear-end and pedestrian crashes. Having considered the actions of 
industry, including those in response to nonregulatory incentives, 
NHTSA has concluded that this rulemaking is necessary to require that 
all new light vehicles are equipped with AEB systems and to set 
specific performance requirements for AEB systems. 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 
percent of new vehicles meeting the lead vehicle test procedures 
included in NCAP.\100\ Similarly, the voluntary commitment resulted in 
approximately 90 percent of new light vehicles having an AEB 
system.\101\
---------------------------------------------------------------------------

    \100\ 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.
    \101\ Id.
---------------------------------------------------------------------------

    However, NHTSA has tentatively concluded that these actions have 
insufficiently addressed the safety problem associated with rear-end 
and pedestrian crashes for three primary reasons. First, 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.
    Second, 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. 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

[[Page 38655]]

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.
    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 draft PAEB test procedures.
    This proposed rule includes three basic lead vehicle AEB test 
scenarios--stopped, slower-moving, and decelerating lead vehicle. Each 
lead vehicle AEB scenario has performance requirements at specific 
speeds or ranges of speeds. Each scenario also includes performance 
requirements with and without manual braking. NHTSA's general approach 
in developing performance requirements was to consider the state of AEB 
technology and its ability to address crashes. Key parameters were 
identified that are important in differentiating between AEB systems 
that are effective at preventing crashes, and AEB systems that only 
engage in narrow and very controlled conditions, with the latter being 
potentially less effective at reducing fatalities and injuries. For 
example, a system that only automatically applies the brakes where the 
posted speed limit is 25 mph or less would be effective at preventing 
property damage rear-end crashes, but would prevent very few fatalities 
and injuries. Likewise, PAEB systems that are unable to prevent crashes 
in low-light ambient conditions would fail to reduce a large portion of 
pedestrian fatalities. Considering the ability of current AEB 
technology to safely prevent crashes, and using information from 
vehicle testing, NHTSA is proposing requirements, including test 
scenarios and parameters, that are either within the capability of at 
least one recent production vehicle or for which there is a practical 
engineering basis for the prescribed capability in current AEB systems.
    The proposal requires a vehicle to provide a FCW and have an 
emergency braking system that automatically applies the brakes when a 
collision with the rear of another vehicle or a pedestrian is imminent 
at speeds above 10 km/h (6.2 mph). Furthermore, proposed AEB 
performance requirements will ensure that an AEB system is able to 
completely avoid collision with the rear of another vehicle or a 
pedestrian. Specifically, the proposal includes a set of performance 
requirements for vehicle-level track testing that will realistically 
evaluate vehicles at normal driving speeds and introduce test devices 
for which vehicles must automatically brake in a way that avoids any 
impact with the objects. The requirements include lead vehicle AEB test 
scenarios, where the test object that must be avoided is the lead 
vehicle test device, and PAEB test scenarios, where the object that 
must be avoided is a pedestrian test mannequin. In all tests that 
include a test device, the observable and objective criterion for 
passing is avoiding contact with the object. The agency is proposing 
additional system requirements for false activation and provisions for 
indicating AEB malfunction to the vehicle operator.

A. Lead Vehicle AEB System Requirement

    The agency is proposing that vehicles be required to have a forward 
collision warning system and an automatic emergency braking system that 
are able to function continuously to apply the service brakes 
automatically when a collision with a vehicle or object is imminent. 
The system must operate when the vehicle is traveling at any forward 
speed greater than 10 km/h (6.2 mph). This is a general system 
equipment requirement with no associated performance test. No specific 
speed reduction or crash avoidance would be required. However, this 
requirement is included to ensure that AEB systems are able to function 
at all times, including at speeds above those NHTSA is proposing as 
part of the performance test requirements.
    This requirement complements the performance requirements in 
several ways. While the track testing described below provides a 
representation of real-world crash events, no amount of track testing 
can fully duplicate the real world. This requirement ensures that the 
AEB's perception system identifies and automatically detects a vehicle, 
warns the driver, and applies braking when a collision is imminent. 
This requirement also ensures that AEB systems continue to function in 
environments that are not as controlled as the test track environment. 
For example, unlike during track testing, other vehicles, pedestrians, 
bicyclists, and buildings may be present within the view of the 
sensors. Finally, track test equipment limitations and safety 
considerations limit the ability to test at high speeds. However, 
crashes still occur at higher travel speeds. The automatic braking 
requirement ensures that AEB systems continue to provide safety 
benefits at speeds above those for which a track-testing requirement is 
currently not practicable, either because of performance capabilities 
or track test limitations. Where a performance standard is not 
practical or does not sufficiently meet the need for safety, NHTSA may 
specify an equipment requirement as part of an FMVSS.\102\
---------------------------------------------------------------------------

    \102\ See 72 FR 17235, 17299 (Apr. 6, 2007) (discussing the 
understeer requirement in FMVSS No. 126); Chrysler Corp. v. DOT, 515 
F.2d 1053 (6th Cir. 1975) (holding that NHTSA's specification of 
dimensional requirements for rectangular headlamps constitutes an 
objective performance standard under the Safety Act).
---------------------------------------------------------------------------

    Enforcement of such a performance requirement can be based on 
evidence obtained by engineering investigation that might include a 
post-crash investigation and/or system design investigation. For 
instance, if a crash occurs in which the vehicle under examination has 
collided with a lead vehicle, NHTSA could investigate the details 
surrounding the crash to determine if a warning was provided and the 
automatic emergency braking system applied the service brakes 
automatically. In appropriate cases in the context of an enforcement 
proceeding, NHTSA could also use its information-gathering authority to 
obtain information from a manufacturer describing the basis on which it 
certified that its FCW and AEB systems meet this proposed requirement.

B. Forward Collision Warning Requirement

    NHTSA is proposing that AEB-equipped vehicles must have forward 
collision warning functionality that provides a warning to the vehicle 
operator if a forward collision with a lead vehicle is imminent. The 
proposal defines FCW as an auditory and visual warning provided to the 
vehicle operator that is designed to elicit an immediate crash 
avoidance response by the vehicle operator. The system must operate 
when the vehicle is traveling at any forward speed greater than 10 km/h 
(6.2 mph).

[[Page 38656]]

    While some vehicles are equipped with alerts that precede the FCW 
and research has examined their use, NHTSA's proposal is not specifying 
an advisory or preliminary alert that would precede the FCW. Lerner, 
Kotwal, Lyons, and Gardner-Bonneau (1996) differentiated between an 
imminent alert, which ``requires an immediate corrective action,'' and 
a cautionary alert, which ``alerts the operator to a situation which 
requires immediate attention and may require a corrective action.'' 
\103\ A 2004 NHTSA report titled ``Safety Vehicles using adaptive 
Interface Technology (Task 9): A Literature Review of Safety Warning 
Countermeasures,'' examined the question of whether to include a 
cautionary alert level in an FCW system. Although the two FCW 
algorithms in the Automotive Collision Avoidance System Field 
Operational Test algorithms included a cautionary phase, the Collision 
Avoidance Metrics Partnership (1999) program recommended that only 
single (imminent) stage warnings be used.
---------------------------------------------------------------------------

    \103\ Lerner, Kotwal, Lyons, and Gardner-Bonneau (1996). 
Preliminary Human Factors Guidelines for Crash Avoidance Warning 
Devices. DOT HS 808 342. National Highway Traffic Safety 
Administration.
---------------------------------------------------------------------------

    Unlike the FCW required as part of the track testing, NHTSA is not 
specifically requiring that FCW presentation occur prior to the onset 
of braking in instances that are not tested on the track. This is to 
provide manufacturers with the flexibility to design systems that are 
most appropriate for the complexities of various crash situations, some 
of which may provide very little time for a driver to take action to 
avoid a crash. A requirement that FCW occur prior to automatic braking 
could suppress the automatic braking function in some actual driving 
scenarios, such as a lead vehicle cutting immediately in front of an 
AEB-equipped vehicle, where immediate automatic braking should not wait 
for a driver warning.
1. FCW Modalities
    Since approximately 1994, NHTSA has completed research and 
published related reports for more than 35 research efforts related to 
crash avoidance warnings or forward collision warnings. These research 
efforts, along with other published research and existing ISO standards 
(15623 and 22839) and SAE International (SAE) documents (J3029 and 
J2400), provide a basis for the proposed requirements.\104\
---------------------------------------------------------------------------

    \104\ ISO 15623--Forward vehicle collision warning systems--
Performance requirements and test procedures; ISO 22839--Forward 
vehicle collision mitigation systems--Operation, performance, and 
verification requirements (applies to light and heavy vehicles); SAE 
J3029: Forward Collision Warning and Mitigation Vehicle Test 
Procedure and Minimum Performance Requirements--Truck and Bus (2015-
10; WIP currently); SAE J2400 2003-08 (Information report). Human 
Factors in Forward Collision Warning Systems: Operating 
Characteristics and User Interface Requirements.
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    NHTSA NCAP and Euro NCAP information relating to FCW was also 
considered. Since model year 2011, the agency has included FCW as a 
recommended technology in NCAP and identifies to consumers which light 
vehicles have FCW systems that meet NCAP's performance tests. NHTSA's 
March 2022 request for comments notice on proposed changes to NCAP 
sought comment on which FCW modalities or modality combinations should 
be necessary to receive NHTSA's NCAP recommendation.\105\ Commenters 
generally supported the use of a multimodal FCW strategy. The Alliance 
for Automotive Innovation and Intel both advocated allowing credit for 
any effective FCW signal type. Multiple commenters supported allowing 
NCAP credit for FCW having either auditory or haptic signals. BMW, 
Stellantis, and General Motors supported use of FCW auditory or haptic 
signals in addition to a visual signal. NTSB and Advocates for Highway 
and Auto Safety recommended that NHTSA conduct research examining the 
human-machine interface and examine the effectiveness of haptic warning 
signals presented in different locations (e.g., seat belt, seat pan, 
brake pulse). Dynamic Research, Inc. advocated allowing NCAP credit for 
implementation of a FCW haptic brake pulse, while ZF supported use of a 
haptic signal presented via the seat belt. Bosch warned that use of a 
haptic signal presented via the steering wheel for lane keeping or 
blind spot warning and FCW should be avoided as it may confuse the 
driver. The Alliance for Automotive Innovation raised the potential 
benefits of standardizing the warning characteristics to improve 
effectiveness as individuals move from vehicle to vehicle.
---------------------------------------------------------------------------

    \105\ 87 FR 13452 (Mar. 9, 2022).
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    All current U.S. vehicle models appear to provide auditory and 
visual FCW signals, while only a few manufacturers also provide a 
haptic signal (e.g., seat pan vibration or a brake pulse). Visual FCW 
signals in current models consist of either a symbol or word (e.g., 
``BRAKE!''), presented on the instrument panel or head-up display, and 
most are red.
    For this NPRM, NHTSA proposes that the FCW be presented to the 
vehicle operator via at least two sensory modalities, auditory and 
visual. Use of a multimodal warning ensures that most drivers will 
perceive the warning as soon as its presented, allowing the most time 
for the driver to take evasive action to avoid a crash. As a vehicle 
operator who is not looking toward the location of a visual warning at 
the time it is presented may not see it, NHTSA's proposal views the 
auditory warning signal as the primary modality and the visual signal 
as a secondary, confirmatory indication that explains to the driver 
what the warning was intended to communicate (i.e., a forward crash-
imminent situation). However, because hearing-impaired drivers may not 
perceive an FCW auditory signal, a visual signal would be important for 
presenting the FCW to hearing-impaired individuals.
    A multimodal FCW strategy is consistent with the recommendations of 
multiple U.S. and international organizations including ISO, SAE 
International, and Euro NCAP. ISO recommends a multimodal approach in 
both ISO 15623, ``Forward vehicle collision warning systems--
Performance requirements and test procedures,'' and ISO 22839, 
``Forward vehicle collision mitigation systems--Operation, performance, 
and verification requirements'' (which applies to light and heavy 
vehicles). SAE addresses the topic of a multimodal FCW strategy in both 
information report J2400 2003-08, ``Human Factors in Forward Collision 
Warning Systems: Operating Characteristics and User Interface 
Requirements,'' and J3029, ``Forward Collision Warning and Mitigation 
Vehicle Test Procedure and Minimum Performance Requirements--Truck and 
Bus (2015-10; Work in Progress currently).'' Most of these 
recommendations specify an FCW consisting of auditory and visual 
signals, while ISO 15623 specifies that an FCW include a visual warning 
as well as an auditory or haptic signal.
2. FCW Auditory Signal Characteristics
    The proposed FCW auditory signal would be the primary means used to 
direct the vehicle operator's attention to the forward roadway and 
should be designed to be conspicuous to quickly capture the driver's 
attention, convey a high level of urgency, and be discriminable from 
other auditory signals presented within the vehicle.\106\ Some 
specifications from NHTSA's ``Human Factors Design Guidance For Driver-
Vehicle Interfaces'' are proposed

[[Page 38657]]

as forward collision warning specifications to meet these 
criteria.\107\ As the FCW auditory signal would be the primary warning 
mode, this signal would not be permitted to be disabled.
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    \106\ DOT HS 810 697, Crash Warning System Interfaces: Human 
Factors Insights and Lessons Learned--Final Report
    \107\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
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    To be conspicuous and quickly capture the driver's attention, the 
FCW auditory signal must ensure that the driver will readily detect the 
warning under typical driving conditions (e.g., ambient noise). The 
auditory signal must be clearly perceptible and quickly focus the 
driver's attention on the forward roadway. To ensure that the FCW 
auditory signal is conspicuous to the vehicle operator, any in-vehicle 
system or device that produces sound that may conflict with the FCW 
presentation would be required to be muted, or substantially reduced in 
volume, during the presentation of the FCW.\108\ In order for the 
warning to be detectable, a minimum intensity of 15-30 dB above the 
masked threshold (MT) should be used.109 110 111 112 Because 
sound levels inside a vehicle can vary based on any number of different 
factors, such as vehicle speed and pavement condition, NHTSA is not 
proposing a specific sound level at this time, but requests comments on 
suitable and reasonable approaches for ensuring that the FCW auditory 
signal can be detected by drivers under typical driving conditions.
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    \108\ DOT HS 810 697, Crash Warning System Interfaces: Human 
Factors Insights and Lessons Learned--Final Report.
    \109\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration. ``The amplitude of auditory signals is in the range 
of 10-30 dB above the masked threshold (MT), with a recommended 
minimum level of 15 dB above the MT (e.g., [1, 2, 3]). 
Alternatively, the signal is at least 15 dB above the ambient noise 
[3].''
    \110\ Campbell, J.L., Richman, J.B., Carney, C., and Lee, J.D. 
(2002). In-vehicle display icons and other information elements. 
Task F: Final in-vehicle symbol guidelines (FHWA-RD-03-065). 
Washington, DC: Federal Highway Administration.
    \111\ International Organization for Standardization (ISO). 
(2005). Road vehicles--Ergonomic aspects of in-vehicle presentation 
for transport information and control systems--Warning systems (ISO/
TR 16532). Geneva, Switzerland: International Organization of 
Standards.
    \112\ MIL-STD-1472F. (1998). Human engineering. Washington, DC: 
Department of Defense.
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    For communicating urgency and ensuring comprehension of auditory 
messages, fundamental frequency, the lowest frequency in a periodic 
signal, is a key design parameter.\113\ Research has shown that 
auditory warning signals with a high fundamental frequency of at least 
800 Hz more effectively communicate urgency.114 115 Greater 
perceived urgency of a warning is associated with faster reaction 
times, which would mean a quicker crash avoidance response by the 
driver.116 117 118 Therefore, NHTSA proposes that the FCW 
auditory signal's fundamental frequency must be at least 800 Hz.\119\ 
Additional proposed FCW auditory signal requirements that support 
communication of the urgency of the situation include a duty 
cycle,\120\ or percentage of time sound is present, of 0.25-0.95, and 
faster auditory signals with a tempo in the range of 6-12 pulses per 
second to be perceived as urgent and elicit rapid driver response.\121\
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    \113\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
    \114\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
    \115\ Guilluame, A., Drake, C., Rivenez, M., Pellieux, L., & 
Chastres, V. (2002). Perception of urgency and alarm design. 
Proceedings of the 8th International Conference on Auditory Display.
    \116\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
    \117\ Campbell, J.L., Richman, J.B., Carney, C., & Lee, J.D. 
(2004). In-vehicle display icons and other information elements, 
Volume I: Guidelines (Report No. FHWA-RD-03-065). Washington, DC: 
Federal Highway Administration. Available at www.fhwa.dot.gov/publications/research/safety/03065/index.cfm.
    \118\ Suied, C., Susini, P., & McAdams, S. (2008). Evaluating 
warning sound urgency with reaction times. Journal of Experimental 
Psychology: Applied, 14(3), 201-212.
    \119\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
    \120\ Duty cycle, or percentage of time sound is present, is 
equal to the total pulse duration divided by the sum of the total 
pulse duration and the sum of the inter-pulse intervals.
    \121\ Gonzalez, C., Lewis, B.A., Roberts, D.M., Pratt, S.M., & 
Baldwin, C.L. (2012). Perceived urgency and annoyance of auditory 
alerts in a driving context. Proceedings of the Human Factors and 
Ergonomics Society Annual Meeting, 56(1), 1684-1687.
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    The FCW auditory signal needs to be easily discriminable from other 
auditory signals in the vehicle. Therefore, vehicles equipped with more 
than one crash warning type should use FCW auditory signals that are 
distinguishable from other warnings.\122\ This proposed requirement is 
consistent with ISO 15623.\123\ Standardization of FCW auditory signals 
would likely be beneficial in ensuring driver comprehension of the 
warning condition across vehicle makes and models. NHTSA invites 
comments on the feasibility of specifying a common FCW auditory signal. 
While this proposal contains no specific requirements ensuring that the 
FCW auditory signal is distinguishable from other auditory warnings in 
the vehicles, NHTSA believes that industry is likely to consider this 
in their vehicle designs as part of their due diligence and safety 
assurance.
---------------------------------------------------------------------------

    \122\ DOT HS 810 697, Crash Warning System Interfaces: Human 
Factors Insights and Lessons Learned--Final Report
    \123\ ISO 15623--Forward vehicle collision warning systems--
Performance requirements and test procedures.
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3. FCW Visual Signal Characteristics
    Current FCWs in the U.S. vehicle fleet use a mix of symbols and 
words as a visual forward collision warning. Use of a common FCW symbol 
across makes and models would help to improve consumer understanding of 
the meaning of FCWs and encourage more appropriate driver responses in 
forward crash-imminent situations.
    ISO 7000, ``Graphical symbols for use on equipment--Registered 
symbols,'' \124\ and the SAE J2400 (2003-08) \125\ information report, 
``Human Factors in Forward Collision Warning Systems: Operating 
Characteristics and User Interface Requirements,'' contain recommended 
FCW symbols shown in Figure 1. These symbols are similar as they both 
communicate a forward impact, while the ISO symbol portrays the forward 
impact as being specifically with another vehicle.
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    \124\ ISO 7000--Graphical symbols for use on equipment--
Registered symbols.
    \125\ SAE J2400 (info. report, not RP or standard), 2003-08. 
Human Factors in Forward Collision Warning Systems: Operating 
Characteristics and User Interface Requirements.

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[[Page 38658]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.011

    Because the symbol in SAE J2400 relates the idea of a frontal crash 
without depicting a particular forward object, this symbol could 
visually represent and apply to both the lead vehicle and pedestrian 
scenarios. Therefore, NHTSA finds the SAE J2400 symbol to be most 
applicable to the FCW requirements in this proposal. NHTSA proposes 
that FCW visual signals using a symbol must use the SAE J2400 (2003-08) 
symbol.
    Some other vehicle models employ a word-based visual warning, such 
as ``STOP!'' or ``BRAKE!'' SAE J2400 also includes a word-based visual 
warning recommendation consisting of the word, ``WARNING.'' A well-
designed warning should instruct people about what to do or what not to 
do to avoid a hazard. The potential benefit of a word-based warning for 
FCW is that it can communicate to the driver an instruction about what 
to do to avoid or mitigate the crash, thereby expediting the driver's 
initiation of an appropriate crash avoidance response. However, 
Consumer Reports noted in its online ``Guide to forward collision 
warning'' that for some models, visual warning word use was found to be 
confusing to some drivers surveyed.\126\ Respondents reported a common 
complaint that ``their vehicle would issue a visual ``BRAKE'' alert on 
the dash, but it wouldn't bring the car to a stop . . .'' This 
confusion as to whether the word is meant to communicate what the 
driver should do or what the vehicle is doing may stem from drivers 
assuming that any information presented within the instrument panel 
area is communicating something relating to the vehicle's condition or 
state, as symbols presented in that location generally do. Presenting a 
word-based warning in a higher location away from the instrument panel, 
as recommended by SAE J2400, may be interpreted more accurately by 
drivers as well as increase the likelihood of FCW visual warning 
perception by drivers.\127\ NHTSA requests comments on this issue and 
any available objective research data that relates to the effectiveness 
of word-based FCW visual signals in instrument panel versus head-up 
display locations. NHTSA also requests comments regarding whether 
permitting word-based warnings that are customizable in terms of 
language settings is necessary to ensure warning comprehension by all 
drivers.
---------------------------------------------------------------------------

    \126\ ``Guide to forward collision warning: How FCW helps 
drivers avoid accidents.'' Consumer Reports. https://www.consumerreports.org/car-safety/forward-collision-warning-guide/. 
Accessed April 2022.
    \127\ SAE J2400 2003-08 (Information report). Human Factors in 
Forward Collision Warning Systems: Operating Characteristics and 
User Interface Requirements.
---------------------------------------------------------------------------

    One plausible benefit of a word-based visual warning is that some 
word choices that instruct the driver to initiate a particular action, 
such as ``STOP!,'' would be fully applicable to both lead vehicle and 
pedestrian scenarios, whereas a symbol containing an image of a lead 
vehicle would not be directly applicable to a forward pedestrian 
imminent crash scenario. As the response desired from the driver, to 
apply the brakes, is the same for both lead vehicle and forward 
pedestrian scenarios, the content of the visual warning need not be 
specific to the type of forward obstacle, but needs simply to 
communicate the idea of an impending forward crash. NHTSA requests 
comments and any available research data regarding the use and 
effectiveness of obstacle-specific symbols and word-based visual 
warnings and the relative effectiveness of word-based visual warnings 
compared to symbols.
    While many current vehicle models present a visual FCW signal 
within the instrument panel, drawing a driver's eyes downward away from 
the roadway to the instrument panel during a forward crash-imminent 
situation is likely to have a negative impact on the effectiveness of 
the driver's response to the FCW. Research indicates that a visual FCW 
signal presented in the instrument panel can slow driver response.\128\ 
The research findings support the SAE J2400 recommendation advising 
against the use of instrument panel based visual FCWs.\129\ SAE J2400 
(2003-08) states:
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    \128\ ``Evaluation of Forward Collision Warning System Visual 
Alert Candidates and SAE J2400,'' SAE Paper No. 2009-01-0547, 
https://trid.trb.org/view/1430473.
    \129\ SAE J2400 2003-08 (Information report). Human Factors in 
Forward Collision Warning Systems: Operating Characteristics and 
User Interface Requirements.

    Visual warnings shall be located within a 10-degree cone of the 
driver's line of sight. Qualitatively, this generally implies a top-of-
dashboard or head-up display location. A conventional dashboard 
location shall not be used for the visual warning. The rationale for 
this is based on the possibility that an instrument panel-based visual 
warning may distract the driver from the hazard ahead.
    This FCW visual signal location guidance is also consistent with 
ISO 15623, which states that the FCW visual signal shall be presented 
in the ``main glance direction.'' Current vehicles equipped with head-
up displays have the ability to present a FCW visual signal within the 
driver's forward field of view. Furthermore, some GM vehicles not 
equipped with head up displays currently have the ability to present a 
FCW visual signal reflected onto the windshield in the driver's forward 
line-of-sight. Despite the FCW visual signal being considered secondary 
to the auditory signal, NHTSA agrees that the effectiveness of a FCW 
visual signal would be maximized for both hearing and hearing-impaired 
drivers if the signal is presented at a location within the driver's 
forward field of view above the instrument panel. To ensure maximum 
conspicuity of the FCW visual signal (be it word-based or a symbol), 
NHTSA proposes that it be presented within a 10-degree cone of the 
driver's line of sight. The line of sight

[[Page 38659]]

would be based on the forward-looking eye midpoint (Mf) as 
described in FMVSS No. 111, ``Rear visibility,'' S14.1.5.
    The FCW visual signal would be required to be red, as is generally 
used to communicate a dangerous condition and as recommended by ISO 
15623 and SAE J2400 (2003-08). Because the FCW visual signal is 
intended to be confirmatory for the majority of drivers, the symbol 
would be required to be steady burning.
4. FCW Haptic Signal
    The agency considered also specifying a complementary haptic FCW 
signal as part of the proposed FCW specifications. Currently, only a 
portion of U.S. vehicles equipped with forward collision warning 
include a haptic warning component. For example, General Motors 
vehicles equipped with the haptic warning feature can present either a 
haptic seat pulse (vibration) or auditory warning based on a driver-
selectable setting. Some other vehicle manufacturers, such as 
Stellantis and Audi, use a brake pulse, or brief deceleration of the 
vehicle, as part of the FCW. Some Hyundai/Kia models incorporate a 
haptic steering wheel vibration into the FCW. As haptic steering wheel 
signals are used by many lane keeping features of current vehicles to 
encourage drivers to steer the vehicle back toward the center of the 
lane, providing a haptic FCW signal via the steering wheel may result 
in driver confusion and be less effective in eliciting a timely and 
beneficial driver response.
    ISO 15623 allows a haptic signal as an alternative to an auditory 
signal.\130\ It permits a haptic brake pulse warning with a duration of 
less than 1 second when the driver is not already applying the brakes. 
ISO 15623 also allows actuation of a seat belt pretensioner as a haptic 
FCW signal.
---------------------------------------------------------------------------

    \130\ ISO 15623--Forward vehicle collision warning systems--
Performance requirements and test procedures.
---------------------------------------------------------------------------

    Some research has shown that haptic FCW signals can improve crash 
avoidance response. NHTSA research on ``Driver-Vehicle Interfaces for 
Advanced Crash Warning Systems'' found that a haptic signal delivered 
via the seat belt pretensioner would be beneficial in eliciting an 
effective crash avoidance response from the vehicle operator. The 
research showed for FCWs issued at 2.1-s time-to-collision (TTC) that 
seat belt pretensioner-based FCW signals elicited the most effective 
crash avoidance performance.\131\ Haptic FCW signals led to faster 
driver response times than did auditory tonal signals. FCW modality had 
a significant effect on participant reaction times and on the speed 
reductions resulting from participants' avoidance maneuvers (regardless 
of whether a collision ultimately occurred). Brake pulsing or seat belt 
tensioning were found to be effective for returning distracted drivers' 
attention to the forward roadway and eliciting desirable vehicle 
control responses; seat vibration similar to a virtual rumble strip 
(vibrating the front of the seat) was not found to return driver 
attention rapidly and reliably to the forward roadway within the Crash 
Warning Interface Metrics research. Similarly, research by Aust (2014) 
found that ``combining sound with seat belt jerks or a brake pulse 
leads to significantly faster response times than combining the sound 
with a visual warning'' and stated, ``these results suggest that future 
FCWs should include a haptic modality to improve driver performance.'' 
\132\ Aust (2014) also found use of a haptic seat belt FCW signal to be 
slightly more effective (100 ms faster driver response) than a haptic 
brake pulse in one of two scenarios (response times were equal in a 
second scenario). Despite these promising research results associated 
with use of a seat belt based FCW haptic component, NHTSA was unable to 
identify any current U.S. vehicle models equipped with a haptic seat 
belt FCW component.
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    \131\ Lerner, N., Singer, J., Huey, R., Brown, T., Marshall, D., 
Chrysler, S., . . . & Chiang, D.P. (2015, November). Driver-vehicle 
interfaces for advanced crash warning systems: Research on 
evaluation methods and warning signals. (Report No. DOT HS 812 208). 
Washington, DC: National Highway Traffic Safety Administration.
    \132\ Aust, M. (2014) Effects of Haptic Versus Visual Modalities 
When Combined With Sound in Forward Collision Warnings. Driving 
Simulation Conference 2014, Paper number 36. Paris, France, 
September 4-5, 2014.
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    Other studies found FCW haptic brake pulses effective at getting a 
driver's attention and that drivers are more likely to detect a brake 
pulse if it produces a sensation of ``jerk'' or ``self-motion.'' 
133 134 Kolke reported reaction times shortened by one-third 
(approximately 0.3 s, non-signi[filig]cant) when a brake pulse was 
added to an audio-visual warning.\135\ One usability drawback is that 
drivers tend to report that vehicle brake pulses are too disruptive, 
which can lead to unfavorable annoyance.\136\
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    \133\ Lee, J.D., McGehee, D.V., Brown, T.L., & Nakamoto, J. 
(2012). Driver sensitivity to brake pulse duration and magnitude. 
Ergonomics, 50(6), 828-836.
    \134\ Brown, S.B., Lee, S.E., Perez, M.A., Doerzaph, Z.R., 
Neale, V.L., & Dingus, T.A. (2005). Effects of haptic brake pulse 
warnings on driver behavior during an intersection approach. 
Proceedings of the Human Factors and Ergonomics Society 49th Annual 
Meeting, 1892-1896.
    \135\ Kolke, Gauss, and Silvestro (2012). Accident reduction 
through emergency braking systems in passenger cars. Presentation at 
the 8th ADAC/BASt-Symposium ``Driving Safely in Europe.'' October 5, 
2012, Workshop B.
    \136\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
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    Presentation of a FCW haptic signal via the driver's seat pan has 
also been investigated. NHTSA's ``Human factors design guidance for 
driver-vehicle interfaces'' contains best practice information for 
implementation of haptic displays, including ``Generating a Detectable 
Signal in a Vibrotactile Seat.'' \137\ In a large-scale field test of 
FCW and LDW systems on model year 2013 Chevrolet and Cadillac vehicles, 
the University of Michigan Transportation Research Institute and GM 
found that GM's Safety Alert Seat, which provides haptic seat vibration 
pulses, increases driver acceptance of both FCW and LDW systems 
compared to auditory signals.\138\
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    \137\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
    \138\ Flannagan, C., LeBlanc, D., Bogard, S., Nobukawa, K., 
Narayanaswamy, P., Leslie, A., Kiefer, R., Marchione, M., Beck, C., 
and Lobes, K. (2016, February), Large-scale field test of forward 
collision alert and lane departure warning systems (Report No. DOT 
HS 812 247), Washington, DC: National Highway Traffic Safety 
Administration.
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    NHTSA's March 2022 request for comments notice on the NCAP sought 
comment on which FCW modalities or modality combinations should receive 
credit and asked specific questions regarding haptic signals and 
whether certain types should be excluded from consideration (e.g., 
because they may be such a nuisance to drivers that they are more 
likely to disable the FCW or AEB system). A preliminary review of 
comments on that notice found multiple comments highlighting a need for 
more research relating to FCW signals. The National Transportation 
Safety Board highlighted the need for additional information regarding 
haptic signals presented in different locations, stating ``[w]ithout 
examining the efficacy of different means of providing haptic alerts 
and defining appropriate, research-supported implementations, a prudent 
approach would give credit only for audible unimodal alerts or for bi-
modal alerts that include audible alerts.'' Rivian stated ``[t]he 
agency should award credit to systems that provide both audible and 
haptic alerts

[[Page 38660]]

and provide the option to turn either of them OFF based on driver 
preference. These audible or haptic alerts should be in sync with 
providing a visual alert of an impending collision. The agency should 
recommend the decibel level and the haptic feedback location and type 
as a baseline and based on research on reducing nuisance to the 
driver.'' As the agency is actively reviewing comments, NHTSA is not 
proposing to require a complementary FCW haptic signal component at 
this time.
    Given the lack of consensus within available research as to the 
best location for a FCW haptic signal (seat belt, seat pan, steering 
wheel, or brake pulse), NHTSA is not at this time proposing to require 
a haptic FCW component, but invites comment on whether requiring FCW to 
contain a haptic component presented via any location may increase FCW 
effectiveness or whether a FCW haptic signal presented in only one 
specific, standardized location should be allowed.
    While the FCW auditory signal is envisioned as being the primary 
means of warning the driver, providing a haptic FCW signal that would 
complement or supplant the auditory warning signal would likely improve 
FCW perception for hearing-impaired drivers. Some drivers also may 
prefer an alternative modality to auditory warnings (e.g., due to 
annoyance caused by the auditory warning). However, the degree of 
additional benefit that may be accrued by requiring a haptic FCW signal 
in addition to a well-designed auditory and visual FCW that meets the 
specifications proposed is not known.
    A haptic FCW signal, to be effective, would necessarily require the 
driver to be in physical contact with the vehicle component through 
which the haptic signal is presented in order to perceive the warning. 
For example, if the driver is not wearing a seat belt, a haptic FCW 
signal presented via the seat belt would not be effectively received. A 
seat pan based haptic FCW signal would be unlikely to have such a non-
contact issue. Providing a haptic FCW signal would increase the 
likelihood of FCW perception by hearing-impaired drivers and could also 
be used to provide an alternative modality to drivers who do not prefer 
auditory warnings. NHTSA is interested in research data documenting the 
comparison of a compliant auditory-visual FCW to that same FCW with an 
added haptic component. NHTSA also welcomes any objective data 
documenting the relative effectiveness of different haptic signal 
presentation locations for FCW use.

C. Lead Vehicle AEB--Performance Test Requirements

    In addition to the requirement that vehicles must provide a forward 
crash warning and automatically control the brakes to reduce the 
vehicle's speed, the agency is proposing performance test requirements 
that involve a no collision criterion under specific testing scenarios. 
NHTSA is proposing lead vehicle AEB performance tests requiring a 
vehicle to automatically brake or supplement insufficient manual 
braking as a means of avoiding contact with the lead vehicle under 
three specific test scenarios--stopped lead vehicle, slower-moving lead 
vehicle, and decelerating lead vehicle.
    The scenarios are implemented using track tests and are based on 
those used in NCAP and NHTSA's research testing to evaluate AEB 
systems.\139\ The proposed performance criterion for all AEB tests 
involving a lead vehicle is full collision avoidance, meaning the 
subject vehicle must not contact the lead vehicle. NHTSA chose the 
performance criterion of collision avoidance because it maximizes the 
safety benefits of the rule as compared to a metric that might permit a 
reduced speed collision. NHTSA has tentatively concluded that a no-
contact criterion for the performance test requirements is practicable 
to achieve, consistent with the need for safety, and may be necessary 
to ensure test repeatability.\140\
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    \139\ 87 FR 13452 (Mar. 9, 2022).
    \140\ Requiring vehicles to avoid contact during testing 
addresses practical considerations as well. These practical 
considerations are discussed in section VI.G of this NPRM, in which 
NHTSA seeks comment on alternatives to the no-contact requirement.
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    The lead vehicle AEB tests include parameters necessary to fully 
define the initial test conditions in each scenario. Key test 
parameters for the lead vehicle AEB tests include the travel speed of 
both the subject vehicle and lead vehicle, the initial headway between 
the subject vehicle and the lead vehicle, the deceleration of the lead 
vehicle, and any manual brake application made to the subject vehicle. 
Some of these key parameters are chosen from a range of values.\141\ 
The use of a range of potential values allows the agency to ensure that 
AEB system performance remains consistent, as test parameters vary 
within the bounds of the range. During testing, some AEB systems 
performed better at high speeds and did not perform well at lower 
speeds.\142\ The key proposed test parameters and the combinations in 
which they will be used are summarized in Table 21. The sections that 
follow provide more detail about the selection of these test 
parameters.
---------------------------------------------------------------------------

    \141\ In instances where an FMVSS includes a range of values for 
testing and/or performance requirements, 49 CFR 571.4 states, ``The 
word any, used in connection with a range of values or set of items 
in the requirements, conditions, and procedures of the standards or 
regulations in this chapter, means generally the totality of the 
items or values, any one of which may be selected by the 
Administration for testing, except where clearly specified 
otherwise.''
    \142\ https://www.regulations.gov/document/NHTSA-2021-0002-0002.

                       Table 21--Lead Vehicle AEB Collision Avoidance--Key Test Parameters
----------------------------------------------------------------------------------------------------------------
                                        Speed (km/h)                              Lead Vehicle
                             ---------------------------------   Headway \1\      Deceleration     Manual brake
                              Subject vehicle   Lead vehicle         (m)              (g)          application
----------------------------------------------------------------------------------------------------------------
Stopped Lead Vehicle........  Any 10-80......               0  ...............  ...............  No.
                              Any 70-100.....               0  ...............  ...............  Yes.
Slower-Moving Lead Vehicle..  Any 40-80......              20  ...............  ...............  No.
                              Any 70-100.....              20  ...............  ...............  Yes.
Decelerating Lead Vehicle...  50.............              50  Any 12-40......  Any 0.3-0.5....  No.
                              50.............              50  Any 12-40......  Any 0.3-0.5....  Yes.
                              80.............              80  Any 12-40......  Any 0.3-0.5....  No.
                              80.............              80  Any 12-40......  Any 0.3-0.5....  Yes.
----------------------------------------------------------------------------------------------------------------
\1\ Where headway is not noted, headway is not a key parameter. The initial headway for these scenarios is based
  on the travel speeds and is defined within the detailed test conditions.


[[Page 38661]]

    The stopped lead vehicle scenario consists of the vehicle traveling 
straight ahead, at a constant speed, approaching a stopped lead vehicle 
in its path. The vehicle must be able to avoid contact with the stopped 
lead vehicle. The slower-moving lead vehicle scenario involves the 
subject vehicle traveling straight ahead at constant speed, approaching 
a lead vehicle traveling at a slower speed in the subject vehicle path. 
The decelerating lead vehicle scenario is meant to assess the AEB 
performance when the subject vehicle and lead vehicle initially are 
travelling at the same constant speed in a straight path and the lead 
vehicle begins to decelerate.
    The agency proposes testing under two conditions. In one condition, 
NHTSA would test without any manual brake application. This would 
simulate a scenario where a driver does not intervene at all in 
response to the FCW or impending collision. In the other condition, 
NHTSA would test with manual brake application that would not be 
sufficient to avoid the crash. Not only does the second condition 
ensure that the AEB will supplement the manual braking when needed, it 
also provides a way by which to ensure that an application of 
insufficient manual braking does not suppress automatic braking in 
circumstances where it is initiated before the manual brake application 
is used.
    The proposed speed ranges were selected based on the speeds at 
which rear-end crashes tend to happen, while considering two primary 
factors. The first factor is the practical ability of AEB technology to 
consistently operate and avoid contact with a lead vehicle. NHTSA's 
2020 research testing at 72.4 km/h suggested that the selected speed 
ranges for the various scenarios are within the capabilities of at 
least some MY 2020 AEB-equipped production vehicles. Where a speed 
range is proposed, it is meant to ensure AEB system robustness. As an 
example, during the agency's AEB research testing, two vehicles 
performed better at higher speeds (48 km/h or 30 mph) than at lower 
speeds (40 km/h or 25 mph) in the lead vehicle stopped tests, which 
suggests that the performance degradation at lower speeds was not due 
to the vehicles' brake capabilities.\143\
---------------------------------------------------------------------------

    \143\ https://www.regulations.gov/document/NHTSA-2021-0002-0002.
---------------------------------------------------------------------------

    The second factor is the practical limits of safely conducting 
track tests of AEB systems. Based on the available data, a majority of 
fatalities and injuries from rear-end crashes occur at posted speeds up 
to 60 mph (97 km/h). Due to the tendency of fatalities and injuries to 
increase as the vehicle travel speed increases, this proposal would 
allow for AEB system testing at the highest speeds at which NHTSA can 
safely and repeatably conduct tests. If the system does not intervene 
as required and the subject vehicle collides with the lead vehicle test 
device, it should do so in a manner that will not injure any vehicle 
occupants while also limiting damage to the subject vehicle and test 
equipment.
    The proposed speed ranges were informed based on the results from 
the 2020 NHTSA research. When discussing the research as it relates to 
this notice, the tested vehicles were assigned an identifier as shown 
in Table 22. Additional detail can be found in the Preliminary 
Regulatory Impact Assessment for this rulemaking.\144\
---------------------------------------------------------------------------

    \144\ The Preliminary Regulatory Impact Analysis can be found in 
the docket of this notice.

     Table 22--NHTSA R&D AEB Tested Vehicles and Assigned Identifier
------------------------------------------------------------------------
            Identifier                             Vehicle
------------------------------------------------------------------------
V1................................  2020 Nissan Altima.
V2................................  2020 Volvo S60 T6 AWD Momentum.
V3................................  2020 Honda Odyssey EX-L.
V4................................  2020 Toyota Corolla LE.
V5................................  2020 Ford F-150 4X4 SuperCrew.
V6................................  2020 Subaru Outback Premium/LDD.
V7................................  2020 Audi Q5 45 TFSI quattro.
V8................................  2020 Hyundai Palisade SEL FWD.
V9................................  2019 Audi A6 3.0 T quattro.
V10...............................  2020 Land Rover Range Rover Sport
                                     HSE.
V11...............................  2020 Mercedes-Benz GLC 300 4Matic
                                     SUV.
------------------------------------------------------------------------

    Agency CIB testing in the stopped lead vehicle scenario at 72.4 km/
h (45 mph)--8 km/h (5 mph) lower than the proposed speeds--of 11 MY 
2019/2020 vehicles found two vehicles avoided contact with a stopped 
lead vehicle in five consecutive tests (See Figure 2).\145\ NHTSA's 
evaluation of model year 2021 and 2022 includes tests performed at the 
proposed speeds. The results of this testing are detailed in the lead 
vehicle AEB report docketed with this proposed rule.
---------------------------------------------------------------------------

    \145\ National Highway Traffic Safety Administration (2022, 
March), ``Final MY2019/MY2020 Research Reports for Pedestrian 
Automatic Emergency Braking, High-Speed Crash Imminent Braking, 
Blind Spot Warning, and Blind Spot Intervention Testing,'' https://www.regulations.gov, Docket No. NHTSA-2021-0002-0002.
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BILLING CODE 4910-59-P

[[Page 38662]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.012

    At this time, the agency has tentatively concluded that the maximum 
practicable test speed is 100 km/h (62 mph) and the maximum speed 
differential between the subject vehicle and the lead vehicle is 80 km/
h (50 mph). The proposed test speed ranges reflect this conclusion.
1. Stopped Lead Vehicle Scenario Test Speeds
    The two different speed ranges proposed for the AEB stopped lead 
vehicle tests are dependent on whether the brakes were applied manually 
in the subject vehicle during the test. For tests with no manual brake 
application, the test speed is chosen from any speed between 10 km/h (6 
mph) and 80 km/h (50 mph). For tests with manual brake application, the 
test speed is chosen from any speed between 70 km/h (44 mph) and 100 
km/h (62 mph).
    For the stopped lead vehicle scenario, the proposed lower bound of 
the speed range is 70 km/h (44 mph) when testing with manual brake 
application and the lower bound of the speed range for the condition of 
no manual brake application is specified is 10 km/h (6 mph). This 
presents an overlap in test speeds where manual braking and automatic 
braking might occur. The overlap of the speed ranges is intended 
evaluate AEB system robustness by ensuring that automatic braking still 
occurs if manual braking is insufficient to avoid the crash scenario. 
NHTSA believes that by testing at the higher end of the proposed speed 
range manufacturers will extend this functionality to the entire speed 
range and the testing burden can be reduced.
    To assure that AEB system functionality with and without manual 
brake application exists, the speed ranges when testing with and 
without manual brake application overlap between 70 km/h (44 mph) and 
80 km/h (50 mph). Because AEB systems must activate with or without 
manual brake application at all speeds above 10 km/h (6 mph), 
evaluating the subject vehicle braking performance with and without 
manual brake application from 70 km/h (44 mph) to 80 km/h (50 mph) 
provides a basis for comparison and a way to ensure that performance of 
the AEB system with manual brake application does not affect the 
ability of the subject vehicle to avoid colliding with the lead 
vehicle. These are the same criteria as proposed for AEB system 
performance without manual brake application.
    The upper bound when testing with no manual brake application is 80 
km/h (50 mph) since this is the highest practicable test speed 
differential.\146\ Similarly, the 100 km/h (62 mph) upper bound for the 
manual brake application scenario is the highest practicable test speed 
and testing speed differential.\147\ Testing with the subject vehicle 
speed of 80 km/h (50 mph) is consistent with NHTSA's NCAP request for 
comments notice and Euro NCAP test speeds.\148\
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    \146\ See Travel Speed introduction section for further details.
    \147\ Under the proposed scenario the subject vehicle traveling 
at 100 km/h (62 mph) under constant average deceleration of 0.4 g 
would impact the lead vehicle in similar manner to the vehicle 
traveling at 80 km/h (50 mph) with no manual brake application.
    \148\ See NHTSA's NCAP Request for Comments notice (87 FR 13452 
(Mar. 9, 2022) at 13485, 13487) and Euro NCAP test speeds (Euro NCAP 
TEST PROTOCOL--AEB VRU systems 3.0.2, July 2019).
---------------------------------------------------------------------------

2. Slower-Moving Lead Vehicle Scenario Test Speeds
    In the slower-moving lead vehicle scenario, the proposed subject 
vehicle test speed is any speed between 40 km/h (24.9 mph) and 80 km/h 
(50.0 mph). Given that the lead vehicle speed is always 20 km/h (12.4 
mph) during the proposed lead vehicle moving test, this translates to a 
relative speed range of 20 km/h (12.4 mph) to 60 km/h (37.3 mph). 
Because the stopped lead vehicle test is almost always more stringent 
than the slower-moving lead vehicle test (both in

[[Page 38663]]

terms of the AEB sensing/recognition and braking timing) NHTSA 
tentatively concludes that AEB performance at relative speeds below 20 
km/h (12.4 mph) is adequately evaluated by the proposed stopped lead 
vehicle performance requirement, and it would be duplicative to test 
both scenarios at low speeds.
    The second proposed subject vehicle speed range for tests performed 
with manual brake application is any speed between 70 km/h (43.5 mph) 
and 100 km/h (62.1 mph) (the same as for the stopped lead vehicle 
scenario).\149\ Given that the lead vehicle speed is always 20 km/h 
(12.4 mph) during the proposed lead vehicle moving test, this 
translates to a relative speed range of 50 km/h (31.1 mph) to 80 km/h 
(49.7 mph).
---------------------------------------------------------------------------

    \149\ See previous sections from Travel Speed for speed range 
reasoning not mentioned here.
---------------------------------------------------------------------------

    NHTSA's 2020 CIB research testing showed that all 11 tested 
vehicles did not collide with the lead vehicle when the vehicle speed 
was 40 km/h (24.9 mph), and lead vehicle speed was 16 km/h (9.9 mph). 
Furthermore, 10 of the 11 tested vehicles did not collide with the lead 
vehicle when the subject vehicle speed was 72.4 km/h (45.0 mph) and the 
lead vehicle speed was 32.2 km/h (20.0 mph) on all test runs (See 
Figures 3 and 4).\150\ Based on these data, NHTSA proposes one 
consistent 20 km/h (12.4 mph) speed for the slower-moving lead vehicle 
in this test scenario. These speed combinations also align with those 
specified in the March 9, 2022, NCAP RFC for the lead vehicle moving 
scenario, which have been shown to be practicable.\151\
---------------------------------------------------------------------------

    \150\ 87 FR 13452 (Mar. 9, 2022) and National Highway Traffic 
Safety Administration (2022, March), Final MY2019/MY2020 Research 
Reports for Pedestrian Automatic Emergency Braking, High-Speed Crash 
Imminent Braking, Blind Spot Warning, and Blind Spot Intervention 
Testing, https://www.regulations.gov, Docket No. NHTSA-2021-0002-
0002.
    \151\ 87 FR 13452 (Mar. 9, 2022).
    [GRAPHIC] [TIFF OMITTED] TP13JN23.013
    

[[Page 38664]]


[GRAPHIC] [TIFF OMITTED] TP13JN23.014

3. Decelerating Lead Vehicle Scenario Test Speeds
    The initial speed conditions for the decelerating lead vehicle 
scenario are not as critical to the outcome of the test as other 
parameters. Because the subject and lead vehicle speeds are initially 
the same, the main parameters for a successful test outcome are the 
headway and lead vehicle deceleration. Thus, NHTSA proposes to use two 
discrete test speeds rather than a speed chosen from a range for both 
the subject and lead vehicles in the decelerating lead vehicle test 
scenario, and to use ranges for the headway and deceleration 
parameters. This NPRM proposes that both the subject vehicle and lead 
vehicle travel at the same speed of either 50 km/h (31.1 mph) or 80 km/
h (49.7 mph) in tests both with and without manual brake 
application.\152\
---------------------------------------------------------------------------

    \152\ The agency is proposing two discrete speeds, instead of 
one, for the Decelerating Lead Vehicles scenarios to ensure system 
robustness.
---------------------------------------------------------------------------

    NHTSA's 2020 CIB research testing was performed with the subject 
vehicle and lead vehicle traveling at 56.3 km/h (35.0 mph) with a lead 
vehicle deceleration of 0.3g and 0.5g and a headway of 13.8 m (45.0 ft) 
(See Figure 5) as well as with the subject vehicle and lead vehicle 
traveling at 72.4 km/h (45.0 mph) and a deceleration of 0.3g. When 
testing at 56.3 km/h (35.0 mph) with 0.3 g deceleration of the lead 
vehicle, 7 out of 11 vehicles avoided contact with the lead vehicle in 
all tests. Using the same test speeds but 0.5 g deceleration of the 
lead vehicle, 3 out of 11 vehicles avoided contact in all test runs. 
For the testing performed with the vehicle and lead vehicle travelling 
at 72.4 km/h (45.0 mph) and a deceleration of 0.3 g with the same 
headway of 13.8 m (45.0 ft), 4 out of 11 vehicles avoided contact with 
the lead vehicle.

[[Page 38665]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.015

[GRAPHIC] [TIFF OMITTED] TP13JN23.016


[[Page 38666]]


BILLING CODE 4910-59-C
    Headway and lead vehicle deceleration are the main parameters for 
the dynamics of the decelerating lead vehicle test because both subject 
and lead vehicles start the test at the same speed. At the start of the 
test, the proposed headway specifications include any distance between 
12 m (39.4 ft) and 40 m (131.2 ft).\153\ Based on the initial headway 
and lead vehicle deceleration, the most stringent headway and 
deceleration combination is the shortest headway (12 m (39.4 ft)) and 
the greatest deceleration (0.5g). Based on the 2020 research test 
results, which used a 13.8 m (45.3 ft.) headway for the decelerating 
lead vehicle test scenario, NHTSA has tentatively concluded based on 
the 2020 research test results that the proposed 12 m (39.4 ft) headway 
is practicable and is currently performing additional testing at this 
headway.\154\
---------------------------------------------------------------------------

    \153\ The bounds of the headway range are consistent with the 
headways in the April 2021 European New Car Assessment Programme 
(Euro NCAP), Test Protocol--AEB Car-to-Car systems, Version 3.0.3 
for the same scenario.
    \154\ 87 FR 13452 (Mar. 9, 2022).
---------------------------------------------------------------------------

    NHTSA proposes testing at any deceleration of the lead vehicle from 
0.3g to 0.5g during the conduct of the decelerating lead vehicle tests. 
Based on previous agency research, when drivers need to apply the 
brakes in a non-emergency situation, they do so by decelerating up to 
approximately 0.306g, while drivers encountering an unexpected obstacle 
apply the brakes at 0.48g.\155\ NHTSA's past research analysis of event 
data recorder data also showed that drivers applied the brakes at 0.383 
g in rear-end crash scenarios.\156\ Based upon this research, NHTSA has 
tentatively concluded that deceleration between 0.3g and 0.5g is 
representative of manual, on-the-road, service brake application.
---------------------------------------------------------------------------

    \155\ Gregory M. Fitch, Myra Blanco, Justin F. Morgan, Jeanne C. 
Rice, Amy Wharton, Walter W. Wierwille, and Richard J. Hanowski 
(2010, April) Human Performance Evaluation of Light Vehicle Brake 
Assist Systems: Final Report (Report No. DOT HS 811 251) Washington, 
DC: National Highway Traffic Safety Administration, p. 13 and p. 
101.
    \156\ Automatic Emergency Braking System (AEB) Research Report, 
NHTSA, August 2014, pg. 47. https://www.regulations.gov/document/NHTSA-2012-0057-0037.
---------------------------------------------------------------------------

    From NHTSA's 2020 research testing, of the 11 vehicles tested with 
subject vehicle and lead vehicle speeds of 56.3 km/h (35.0 mph), a 
headway of 13.8 m (45 ft) and a lead vehicle deceleration of 0.5g, 3 
vehicles avoided contact on every test run and 2 vehicles avoided 
contact on four out of five tests. When tested with a subject vehicle 
and lead vehicle speed of 56.3 km/h (35.0 mph) and a 0.3g lead vehicle 
deceleration, 7 out of 11 vehicles avoided contact with the lead 
vehicle in every test, and 3 of the other 4 vehicles avoided contact 
with the lead vehicle in five or six out of seven tests. The fourth 
vehicle could not avoid contact with the lead vehicle in the tests, but 
the AEB system provided an average speed reduction of 31 km/h (19.3 
mph) over seven tests. When tested with a subject vehicle and lead 
vehicle speed of 72.4 km/h (45.0 mph) and a 0.3 g deceleration of the 
lead vehicle, 4 out of 11 vehicles avoided contact in every test and 2 
other vehicles avoided contact in all but one test. Three of the 
remaining vehicles avoided contact in one or two tests, while the two 
others could not avoid contact but both demonstrated an average 21 km/h 
(13 mph) speed reduction.
    From these results NHTSA has tentatively concluded that current AEB 
systems will be able to avoid a collision using a 12.0 m (39.3 ft) 
headway, 0.5g lead vehicle deceleration, and 50.0 km/h (31.1 mph) and 
80.0 km/h (49.7 mph) subject vehicle speeds. Further, the agency 
believes that some of the other tested AEB systems have hardware 
capable of full crash avoidance, but the perception software is not 
tuned for the higher lead vehicle deceleration (0.5g).
4. Subject Vehicle Brake Application
    The manual brake application tests two potential functions within 
the AEB system. The first function is directly linked to driver 
engagement. Normally, in a potential rear-end collision event, an FCW 
will be provided before the onset of automatic braking. In situations 
where it is practical for the vehicle to warn prior to automatic 
activation of the brakes, an inattentive driver may re-engage in the 
driving task and apply the brakes. However, in these circumstances, 
research suggests that a driver's brake application typically does not 
take advantage of the full capacity of the foundation braking system, 
and a crash may still occur. The AEB system, on the other hand, can use 
forward-looking sensor input, coupled with brake pressure information, 
to determine that additional braking is needed to avoid a crash. The 
proposed test conditions replicate this situation so that the AEB 
system must provide the additional braking needed to avoid contact with 
the lead vehicle.
    The second function of the tests is to ensure that the brake 
application by the driver in a crash imminent situation does not 
suppress the vehicle's automatic brake application. In other words, the 
brake pedal cannot be used as a means of overriding the AEB system. 
NHTSA recognizes that in some on-road scenarios, high-level emergency 
braking may not be the appropriate vehicle response. If deemed 
necessary to override an emergency braking event, a means to do so can 
be provided.
    All lead vehicle scenarios include a test condition for which a 
manual brake application is used. This is functionally similar to 
NHTSA's NCAP DBS test. When manual brake application is part of the 
test parameters, the service brake on the subject vehicle is applied in 
such a manner that the subject vehicle decelerates with an average 
magnitude of 0.4g (absent automatic braking) starting at 1.0 second 
after onset of the FCW.
    A deceleration of up to 0.5g is expected from a driver during an 
emergency crash imminent brake application. However, research has shown 
that female and older drivers tend not to apply the same force to the 
brake pedal as young male drivers, thus resulting in lower 
deceleration.\157\ Based on this information, for the manual brake 
application tests, the brake pedal will be applied with a displacement, 
force, or some combination thereof, to sufficiently decelerate the 
subject vehicle an average of 0.4g. This is consistent with the manual 
brake applications defined in NHTSA's NCAP test procedures for DBS 
performance assessment and NHTSA's past research analysis of event data 
recorder data from rear-end crashes.158 159
---------------------------------------------------------------------------

    \157\ Gregory M. Fitch, Myra Blanco, Justin F. Morgan, Jeanne C. 
Rice, Amy Wharton, Walter W. Wierwille, and Richard J. Hanowski 
(2010, April) Human Performance Evaluation of Light Vehicle Brake 
Assist Systems: Final Report (Report No. DOT HS 811 251) Washington, 
DC: National Highway Traffic Safety Administration, pp. 104-108.
    \158\ Automatic Emergency Braking System (AEB) Research Report, 
NHTSA, August 2014, pg. 47. https://www.regulations.gov/document/NHTSA-2012-0057-0037.
    \159\ National Highway Traffic Safety Administration (2014, 
August), Dynamic Brake Support Performance Evaluation (working 
draft). Available at: https://www.regulations.gov/document/NHTSA-2012-0057-0038.
---------------------------------------------------------------------------

    The brake will be applied 1.0 second after the vehicle has provided 
an FCW. This 1.0 second delay is based on the time it takes a driver to 
react when presented with an obstacle. Previous NHTSA research has 
shown that on average, it takes drivers 1.04 seconds to begin applying 
the brake when presented with an unexpected obstacle and 0.8 seconds 
when presented with an anticipated obstacle.\160\
---------------------------------------------------------------------------

    \160\ Gregory M. Fitch, Myra Blanco, Justin F. Morgan, Jeanne C. 
Rice, Amy Wharton, Walter W. Wierwille, and Richard J. Hanowski 
(2010, April) Human Performance Evaluation of Light Vehicle Brake 
Assist Systems: Final Report (Report No. DOT HS 811 251) Washington, 
DC: National Highway Traffic Safety Administration, p. 101.

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[[Page 38667]]

D. PAEB System Requirement

    NHTSA is proposing that AEB systems also be able to provide a 
warning to the driver and automatically intervene to avoid or mitigate 
collisions with pedestrians in the vehicle's forward path. Similar to 
the lead vehicle AEB proposal, the performance requirements for PAEB 
are to provide an FCW and automatically apply the service brakes at all 
forward speeds attainable by the vehicle above 10 km/h (6 mph) in 
response to an imminent collision with a pedestrian.\161\ The proposal 
would require that the vehicle completely avoid a collision with a 
pedestrian test mannequin during specific test track scenarios. NHTSA 
is not proposing FCW and AEB systems to be active below 10 km/h (6 
mph), because it has tentatively concluded that AEB systems do not 
offer consistent performance at such low speeds.\162\ A lower bound of 
10 km/h (6 mph), which is 6 km/h (3.7 mph) less than that stipulated in 
NHTSA's 2019 draft PAEB research test procedure, is also consistent 
with the lower bound for testing under the Euro NCAP rating program and 
the proposed lower bound for PAEB testing under the agency's NCAP.\163\ 
Not requiring PAEB to be active below 10 km/h (6 mph) should not be 
construed to preclude making the AEB system active, if possible, at 
speeds below 10 km/h (6 mph). In fact, the agency anticipates that 
manufacturers will make the system available at the lowest practicable 
speed (the manual for 6 of the 11 tested vehicles shows PAEB available 
at speeds below 10 km/h).
---------------------------------------------------------------------------

    \161\ The FCW and brake application need not be sequential.
    \162\ A review of 11 model year 2019/2020 vehicle owner's 
manuals found that PAEB activation ranged from 4.8 km/h (3 mph) to 
11.3 km/h (7 mph) with the average being 7.7 km/h (4.8 mph).
    \163\ European New Car Assessment Program (Euro NCAP) (2019, 
July), Test Protocol--AEB Car- to-Car systems, Version 3.0.2; 87 FR 
13452 (Mar. 9, 2022); and www.regulations.gov, NHTSA Docket No. 
NHTSA-2019-0102-0005.
---------------------------------------------------------------------------

    Automatic braking must be able to decelerate the vehicle when a 
collision with a pedestrian is imminent in the absence of any driver 
brake input. Unlike for lead vehicle AEB, the proposed requirements for 
PAEB do not require that the AEB system supplement the driver's brake 
input. The reason is that the agency has tentatively concluded that, 
due to the sudden succession of events in a potential collision between 
a vehicle and a pedestrian, particularly for the pedestrian crossing 
path scenarios, a driver is unlikely to have enough time to react to 
the crash imminent event, and the vehicle will brake automatically 
without driver input. While this proposal would not specifically 
require PAEB to supplement driver brake input, it anticipates that AEB 
system designs will include this feature.

E. PAEB--FCW Requirement

    NHTSA is proposing that the same FCW specifications outlined for 
the lead vehicle AEB condition be applied to the PAEB condition. The 
FCW system must operate at any forward speed greater than 10 km/h (6.2 
mph). The proposed FCW modalities and related characteristics of 
auditory and visual components are the same for lead vehicle AEB and 
PAEB conditions. NHTSA is proposing that the auditory mode have a high 
fundamental frequency of at least 800 Hz, a duty cycle of 0.25-0.95, 
and tempo in the range of 6-12 pulses per second; the visual mode would 
be located according to SAE 2400 AUG2003 paragraph 4.1.14 and must 
include the crash icon in the bottom right of paragraph 4.1.16.\164\ 
Line of sight as referenced in 4.1.14 would be determined based on the 
forward-looking eye midpoint (Mf) as described in FMVSS No. 
111 S14.1.5.
---------------------------------------------------------------------------

    \164\ SAE 2400 AUG2003, Human Factors in Forward Collision 
Warning Systems: Operating Characteristics and User Interface 
Requirements.
---------------------------------------------------------------------------

    Some current vehicle models display a pedestrian symbol during 
activation of the FCW for PAEB scenarios. However, NHTSA is now aware 
of research or data indicating that displaying a visual symbol that 
corresponds to the type of forward obstacle (i.e., vehicle or 
pedestrian) affects the driver's response. Providing consistency across 
FCWs provided for lead vehicle AEB and PAEB imminent crash scenarios 
should maximize the likelihood that drivers will associate the FCW with 
a forward crash of any sort. As such, the agency is not proposing 
different symbols for the visual FCW modality based on the type of 
forward obstacle to which the AEB is responding.
    When evaluating existing PAEB systems through NHTSA's 2020 research 
testing, the agency found that during certain test scenarios, FCW did 
not occur prior to the onset of automatic braking.\165\ NHTSA 
tentatively concludes that, due to the dynamics of some pedestrian 
crashes that result in a quick succession of events, it is impractical 
to require that the warning and automatic braking be sequential, as it 
could potentially hinder the reaction time of AEB systems. The agency 
anticipates that FCW may occur at any time during the automatic braking 
event. When it occurs after onset of automatic braking, the FCW would 
serve to inform the driver that automatic braking is ongoing, rather 
than solicit a driver response.
---------------------------------------------------------------------------

    \165\ As an example, when testing the Obstructed Running Child, 
Crossing Path from the Right Scenario (see following paragraphs for 
scenario description) with a MY 2020 Subaru Outback traveling at 16 
km/h the onset of the alert was 0.92s (FCW on time history plot) and 
service brake application was at 0.91 s (PAEB on time history plot) 
essentially at the same time. ``Final Report of Pedestrian Automatic 
Emergency Braking System Research Testing of a 2020 Subaru Outback 
Premium/LDD,'' https://www.regulations.gov/document/NHTSA-2021-0002-0002, See: Figure D66. Time History for PAEB Run 180, S1d, Daytime, 
16 km/h.
---------------------------------------------------------------------------

F. PAEB--Performance Test Requirements

    NHTSA is proposing that AEB-equipped vehicles avoid a collision by 
applying the brakes automatically and alerting the vehicle operator 
when a collision with a pedestrian is imminent under specified test-
track scenarios. Similar to the lead vehicle AEB performance test 
requirements, NHTSA has tentatively concluded that a no-contact 
requirement is necessary for PAEB testing in order to maximize safety. 
Even low-speed vehicle impacts with pedestrians can result in 
fatalities and serious injuries. NHTSA has tentatively concluded that a 
no-contact criterion for the performance test requirements is 
practicable to achieve, consistent with the need for safety, and may be 
necessary to ensure test repeatability.\166\
---------------------------------------------------------------------------

    \166\ Requiring vehicles to avoid contact during testing 
addresses practical considerations as well. These practical 
considerations are discussed in section VI.G of this NPRM, in which 
NHTSA seeks comment on alternatives to the no-contact requirement.
---------------------------------------------------------------------------

    The test scenarios proposed for PAEB evaluation involve track tests 
and are based on previous research completed by the agency to evaluate 
existing PAEB systems and on knowledge and experience from developing 
the related NCAP test procedures.\167\ The proposed speed ranges and 
other key parameters detailed in the following sections are based on 
the observed capabilities of PAEB systems, limitations of the 
pedestrian test mannequins, and the safety problem.\168\
---------------------------------------------------------------------------

    \167\ See Research section of this notice, 87 FR 13452 (Mar. 9, 
2022) at 13472 and 13473, and https://www.regulations.gov/document/NHTSA-2021-0002-0002.
    \168\ See Safety Problem section of this notice.
---------------------------------------------------------------------------

    Manual brake application by the driver is not a parameter of the 
proposed test scenarios for PAEB. However, NHTSA anticipates that, 
because AEB systems will be tested under the proposed requirements with 
manual brake activation for lead vehicle, that functionality will exist 
for

[[Page 38668]]

PAEB.\169\ The absence of manual brake application in NHTSA's proposed 
test parameters should not be construed to mean that AEB systems should 
not function when a manually applied brake input is present.
---------------------------------------------------------------------------

    \169\ Since supplementing brake application is a functionality 
that must already exist for the lead vehicle AEB based on this NPRM, 
NHTSA anticipates the same capability will be provided when the 
subject vehicle encounters an emergency braking situation involving 
a pedestrian and manual braking is applied.
---------------------------------------------------------------------------

    The proposed series of on-track tests fall into three groups of 
scenarios based on the pedestrian test mannequin actions. The first 
group of scenarios involves the test mannequin crossing the path of the 
vehicle. In each of the first group of scenarios, the test mannequin 
travels perpendicular to the vehicle's path. In the second group, the 
test mannequin is stationary within the path of the vehicle. In the 
third group, the test mannequin is moving along the travel path of the 
vehicle. In all scenarios, the test is set up such that the subject 
vehicle would collide with the test mannequin if it did not 
automatically brake. The key test parameters for the PAEB test 
scenarios include the type of test mannequin, the initial location of 
the test mannequin, the direction of travel of the test mannequin, the 
point on the subject vehicle that would impact the test mannequin (the 
overlap), the vehicle speed, the speed of the test mannequin, the 
ambient light condition, and the headlamp beam used during darkness
    These key test parameters and the combinations in which they will 
be used are summarized in Table 23. The sections that follow provide 
more detail about how and why these key test parameters where selected.

                                                 Table 23--PAEB Collision Avoidance Key Test Parameters
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                       Speed (km/h)
                                          Pedestrian surrogate reference       Overlap  -----------------------------------------   Lighting condition
                                                     location                    (%)           Subject vehicle        Pedestrian
--------------------------------------------------------------------------------------------------------------------------------------------------------
Crossing Path.......................  Right.................................         25  Any 10-60.................            5  Daylight.
                                      Right.................................         50  Any 10-60                                Daylight.
                                      Right.................................         50  Any 10-60 \1\                            Lower Beams.
                                      Right.................................         50  Any 10-60                                Upper Beams.
                                      Right \2\.............................         50  Any 10-50.................        \3\ 5  Daylight.
                                      Left..................................         50  Any 10-60.................        \4\ 8  Daylight.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stationary Along Path...............  Right.................................         25  Any 10-55.................            0  Daylight.
                                                                                         Any 10-55 \1\.............               Lower Beams.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         Any 10-55                                Upper Beams.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Moving Along Path...................  Right.................................         25  Any 10-65.................            5  Daylight.
                                                                                         Any 10-65 \1\.............               Lower Beams.
                                                                                         Any 10-65 \1\                            Upper Beams.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Final speed range requirements after an additional one-year phase-in.
\2\ Obstructed, running child.
\3\ Running child.
\4\ Running adult.

    There are certain test conditions in Table 23 where the test speed 
would be implemented one additional year after the initial proposed 
phase-in. Based on the performance of existing PAEB systems during the 
agency's dark lower-beam and dark upper-beam pedestrian tests, NHTSA 
proposes a reduced speed range for the first three years after the 
proposed requirements are to take effect. As discussed further in this 
notice, NHTSA has tentatively concluded that this approach would afford 
adequate lead time for vehicle manufacturers and suppliers to adjust 
their PAEB system designs for higher speed ranges in these scenarios. 
Table 24 summarizes the scenarios to which these changes apply. The 
agency proposes that four years after the date of publication of the 
final rule, the performance testing requirements follow all the key 
parameters in Table 23. A more detailed discussion on the phase-in 
appears further below in this section. Concurrent with the development 
of this proposal, NHTSA conducted testing of model year 2021 and model 
year 2022 vehicles using the proposed performance test requirements. 
The details of these tests and results are docketed with this proposed 
rule.

                                      Table 24--PAEB Collision Avoidance Key Test Parameters, Reduced Speed Ranges
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                     Speed (km/h)
                                          Pedestrian surrogate reference      Overlap  ----------------------------------------
                                                     location                   (%)                                    Test        Lighting condition
                                                                                                 Vehicle            mannequin
--------------------------------------------------------------------------------------------------------------------------------------------------------
Crossing Path.......................  Right................................         50  Any 10-40................            5  Lower Beams.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stationary Along Path...............  Right................................         25  Any 10-50................            0  Lower Beams.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Moving Along Path...................  Right................................         25  Any 10-60................            5  Lower Beams.
                                                                                        Any 10-60................               Upper Beams.
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 38669]]

In all PAEB collision avoidance scenarios (see Table 23 and Table 24) 
the vehicle must avoid a collision with the pedestrian through use of 
the vehicle's AEB system without manual brake input.
    NHTSA evaluated various scenarios when developing the draft NCAP 
test procedures for PAEB.\170\ During this evaluation, four scenarios 
were found to account for 98 percent of functional years lost (i.e., 
the years of life lost due to fatal injury and the years of functional 
capacity lost due to nonfatal injury) and the direct economic cost of 
all vehicle-pedestrian crashes, but they only accounted for 46 percent 
of all national pedestrian cases from NHTSA's General Estimate Systems 
database.\171\ These scenarios were subject vehicle traveling straight 
ahead and pedestrian crossing the road, subject vehicle traveling 
straight ahead and pedestrian walking along/against traffic, subject 
vehicle turning right and pedestrian crossing the road, and subject 
vehicle turning left and pedestrian crossing the road.
---------------------------------------------------------------------------

    \170\ Mikio Yanagisawa, Elizabeth Swanson, and Wassim G. Najm 
(2014, April) Target Crashes and Safety Benefits Estimation 
Methodology for Pedestrian Crash Avoidance/Mitigation Systems 
(Report No. DOT HS 811 998) Washington, DC: National Highway Traffic 
Safety Administration, p. xi.
    \171\ T. Miller, J. Viner, S. Rossman, N. Pindus, W. Gellert, J. 
Douglass, A. Dillingham, and G. Blomquist, ``The Costs of Highway 
Crashes''. FHWA-RD-91-055, October 1991.
---------------------------------------------------------------------------

    Further NHTSA research found that, on average, the subject vehicle 
traveling straight ahead and pedestrian crossing the road and subject 
vehicle traveling straight ahead and pedestrian walking along/against 
traffic accounted for approximately 52 percent of vehicle-pedestrian 
crashes and 90 percent of fatal vehicle-pedestrian crashes with a light 
vehicle striking a pedestrian as the first event.\172\ Based on this 
research, the following scenarios are proposed because they would have 
the highest impact on the safety problem.
---------------------------------------------------------------------------

    \172\ Mikio Yanagisawa, Elizabeth D. Swanson, Philip Azeredo, 
and Wassim Najm (2017, April) Estimation of potential safety 
benefits for pedestrian crash avoidance/mitigation systems (Report 
No. DOT HS 812 400) Washington, DC: National Highway Traffic Safety 
Administration, p xiii.
---------------------------------------------------------------------------

1. PAEB Scenario Descriptions
Pedestrian Crossing Path From the Right
    The crossing path from the right scenarios consist of the subject 
vehicle traveling straight ahead at a constant speed towards the adult 
pedestrian test mannequin, which enters its travel path from the right 
side of the vehicle.\173\ The subject vehicle must be able to avoid 
contact with the pedestrian test mannequin crossing its path.
---------------------------------------------------------------------------

    \173\ Travel Path is the path projected onto the road surface by 
a point located at the intersection of the subject vehicle's 
frontmost vertical plane and longitudinal vertical center plane as 
the subject vehicle travels.
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    A basic setup for the pedestrian crossing the path of the vehicle 
from the right scenarios with 25 percent and 50 percent overlap is 
shown in Figure 7.
BILLING CODE 4910-59-P

[[Page 38670]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.017

    In this scenario, an obstructed child pedestrian moves in the 
vehicle's travel path. The child pedestrian is simulated by a child 
pedestrian surrogate that appears from the right of the travel path. 
The pedestrian surrogate crosses the subject vehicle's travel path from 
in front of two stopped vehicle test devices. The VTDs are parked to 
the right of the subject vehicle's travel path, in the adjacent lane, 
at 1.0 m (3 ft) from the side of the subject vehicle. The VTDs are 
parked one after the other and are facing in the same direction as the 
subject vehicle.\174\ The basic setup for the obstructed running child 
pedestrian scenario is shown in Figure 8. The subject vehicle must 
avoid collision with the child pedestrian surrogate without manual 
brake input.
---------------------------------------------------------------------------

    \174\ See the Proposed Test Procedure section of this NPRM for 
further details.

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

[[Page 38671]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.018

    In this scenario, a simulated running adult pedestrian (the 
pedestrian surrogate) crosses into the path of the vehicle traveling 
straight ahead at a constant speed. The pedestrian surrogate enters the 
path from the left side of the vehicle. No contact between the subject 
vehicle and pedestrian surrogate is allowed. For testing, the subject 
vehicle travels at a constant speed when it encounters the pedestrian 
surrogate crossing from the left side. Figure 9 shows the basic setup 
for this scenario.

[[Page 38672]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.019

    In this scenario the pedestrian surrogate, with its back to the 
subject vehicle, is stationary in the travel path of the subject 
vehicle at a 25 percent overlap. The subject vehicle travels at a 
constant speed and encounters the stationary pedestrian surrogate 
positioned in the subject vehicle's path. The subject vehicle must 
completely avoid a collision with the pedestrian surrogate. Figure 10 
shows the basic setup for the pedestrian stationary in the path of the 
subject vehicle.

[[Page 38673]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.020

    In this scenario, a moving pedestrian is traveling along the 
vehicle's path. The vehicle must avoid collision with the pedestrian 
surrogate. Figure 11 shows the basic setup for this scenario.

[[Page 38674]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.021

2. Overlap
    The overlap is the location on the subject vehicle where the 
vehicle would collide with the pedestrian surrogate. Overlap is defined 
as the percent of the vehicle's width that the pedestrian would 
traverse prior to impact if the vehicle's speed and pedestrian's speed 
remain constant. Overlap is based on overall vehicle width, as shown in 
Figure 12, and is the intended point of impact with the pedestrian 
mannequin in the absence of vehicle braking. Two overlaps are proposed 
for testing, a 25 percent overlap and a 50 percent overlap. The minimum 
overlap is 25 percent to allow for the test mannequin to be fully in 
the path of the vehicle. The overlap determines the available time for 
the AEB system to detect and react when a collision with the test 
mannequin is imminent--a 50 percent overlap allows for more time than a 
25 percent overlap.\175\
---------------------------------------------------------------------------

    \175\ As an example, for the timing, for a road width of 3 m (10 
ft), a subject vehicle width of 2 m (7 ft) and the constant 
pedestrian speed of 5 km/h (3 mph), the time it takes the pedestrian 
to travel from the edge of the road to the 25% overlap is 0.72 s and 
the time it takes the pedestrian to travel to the 50% overlap is 
1.08 s.

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

[[Page 38675]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.022

BILLING CODE 4910-59-C
    For the scenarios involving a pedestrian crossing from the right, 
two overlap conditions are proposed: A more challenging test condition 
of 25 percent overlap and a 50 percent overlap to ensure system 
robustness. The 25 percent overlap tests are performed only under 
daylight conditions, while the 50 percent overlap tests are performed 
in all lighting conditions. For the crossing path scenarios, as 
described in the testing section of this notice, the pedestrian 
surrogate continues to travel along its path either until collision 
occurs or it clears the subject vehicle's path. NHTSA also considered a 
75 percent overlap, and this condition was included in the testing 
performed in 2020. As expected, due to the increase in time range 
afforded by a larger overlap, the AEB performance observed when testing 
at 75 percent overlap was substantially similar to the AEB performance 
achieved when testing at 50 percent overlap.\176\ NHTSA believes that a 
75 percent overlap need not be included in the proposed requirements 
because the minimum performance is sufficiently addressed by testing at 
the 25 percent and 50 percent overlap.
---------------------------------------------------------------------------

    \176\ For the 75% overlap condition the agency only performed 
daylight testing. In general, when testing in the daylight 
condition, AEB performance was similar, or better, when testing at 
the 75% overlap versus testing at 50% and 25% overlaps.
---------------------------------------------------------------------------

    Based on the no contact criterion and braking performance observed 
during its 2020 research testing of 11 vehicles, NHTSA is proposing to 
test PAEB performance with the dark upper beam and dark lower beam 
conditions at 50 percent overlap only. NHTSA has tentatively concluded 
that, due to the reduced timing and AEB system reaction time observed 
during the 25 percent overlap tests, testing at 25 percent overlap for 
the dark upper beam and lower beam is not currently practicable. NHTSA 
is also proposing to use only 50 percent overlap in the obstructed 
child running from the right and the running adult from the left 
scenarios due to the same reduced reaction time.
    NHTSA considered requiring testing at 25 percent overlap for all 
crossing path scenarios. However, this would have required reducing the 
subject vehicle speed to allow more reaction time for the AEB system to 
avoid the pedestrian surrogate at the proposed speeds. NHTSA lacks 
information as to practicable maximum test speed for this condition. 
The proposal to test only at 50 percent overlap for certain scenarios 
allows for testing at higher speeds, which is more representative of 
the safety problem, while effectively encompassing tests at 25 percent 
overlap and lower speeds.\177\ Further, if an AEB system is able to 
avoid collision in daylight at 25 percent overlap, poor performance for 
other crossing path scenarios would not be linked to the vehicle's 
braking performance, but rather would likely be linked to the detection 
and processing part of the AEB system.
---------------------------------------------------------------------------

    \177\ For the pedestrian test mannequin to reach the 50 percent 
overlap, it must pass through the 25 percent overlap location. As an 
example, for a road width of 3 m (10 ft), a vehicle width of 2 m (7 
ft), a pedestrian speed of 5 km/h (3 mph), a 0.7 g average 
deceleration and a AEB system which reacts when the pedestrian test 
mannequin reaches the edge of the road, testing with the subject 
vehicle speed of 27 km/h (17 mph) for the crossing path from the 
right scenario at 50 percent overlap is equivalent to testing at 18 
km/h (11 mph) at 25 percent overlap.
---------------------------------------------------------------------------

    The 25 percent overlap for the stationary and along path scenarios 
emulate a pedestrian standing stationary or walking on the roadway in 
the path of the subject vehicle. In along path scenarios in the real 
world, the pedestrian is positioned towards the edge of the roadway in 
the path of the subject vehicle. Positioning the pedestrian surrogate 
at 25 percent overlap assures that the surrogate test target is fully 
in the path of the vehicle. NHTSA has tentatively concluded that a 25 
percent overlap for the along path scenarios also represents a more 
stringent condition than 50 percent overlap for the AEB system, as it 
ensures that the system has an adequate operational field of view and 
is able to identify pedestrians that are not at the center of the 
travel path.
3. Vehicle and Pedestrian Surrogate Travel Speeds
    The proposed subject vehicle and pedestrian surrogate travel speed 
ranges for the PAEB test scenarios were informed by results from 
NHTSA's 2020 research study and results from a NHTSA research program 
examining four vehicles under dark lighting conditions for PAEB 
performance.178 179

[[Page 38676]]

As in the case for lead vehicle AEB, the proposed speed ranges for PAEB 
testing consider two primary factors--the ability of AEB systems to 
consistently operate and avoid contact with the surrogate pedestrian 
and the practical limits for testing safely.\180\
---------------------------------------------------------------------------

    \178\ 87 FR 13452 (Mar. 9, 2022).
    \179\ See 87 FR 13452 (Mar. 9, 2022) Tables 4, 5 and 6 for the 
complete test matrix. The other 4 vehicles tested for PAEB 
functionality under dark lighting conditions were only tested at 16 
km/h and 40 km/h.
    \180\ Where possible and practicable, the proposed speed ranges 
align with the latest NCAP proposed upgrade (87 FR 13452 (Mar. 9, 
2022)). In instances where system performance for existing PAEB was 
lower, or a safety need exists, the top speeds of the ranges were 
adjusted accordingly.
---------------------------------------------------------------------------

    All proposed speed ranges for the PAEB tests have a lower bound of 
10 km/h (6 mph). The upper bound is set at the highest speed NHTSA has 
tentatively determined is practicable. The 10 km/h (6 mph) lower bound 
for the speed range was based on the agency's tentative conclusion that 
PAEB systems may not offer consistent performance at speeds below 16 
km/h (10 mph) and corroborated by NHTSA's 2020 testing. The lower bound 
of 10 km/h (6 mph) is 6 km/h (4 mph) less than that specified in the 
2019 NHTSA draft PAEB research test procedure and is consistent with 
the lower bound established for testing under Euro NCAP's rating 
program and the lower bound proposed for NCAP testing.\181\ The agency 
has tentatively concluded that testing at speeds below 10 km/h is not 
practicable at this time and testing at speeds above 10 km/h 
sufficiently addresses performance of AEB systems at low speeds. 
Concurrent with the development of this proposed rule, NHTSA performed 
PAEB testing on model year 2021 and 2022 vehicles using the proposed 
performance requirements and test procedures. The results of that 
testing provide additional support to the tentative conclusion that the 
test conditions, parameters, and procedures are practical to conduct 
and that the proposed requirements are practical for manufacturers to 
achieve. The results of this testing are detailed in the PAEB report 
docketed with the proposed rule.
---------------------------------------------------------------------------

    \181\ https://www.euroncap.com/en/for-engineers/protocols/vulnerable-road-user-vru-protection/, 87 FR 13452 (Mar. 9, 2022) and 
https://www.regulations.gov/document/NHTSA-2019-0102-0005.

                       Table 25--User Manual PAEB Range of Functionality by Tested Vehicle
----------------------------------------------------------------------------------------------------------------
                                                                               Speed
                     Vehicle                     ---------------------------------------------------------------
                                                    Low (km/h)       Low (mph)      High (km/h)     High (mph)
----------------------------------------------------------------------------------------------------------------
V1..............................................             9.6               6            59.2              37
V2..............................................             4.8               3              80              50
V3..............................................             4.8               3            99.2              62
V4..............................................            11.2               7              80              50
V5..............................................             4.8               3             120              75
V6..............................................            11.2               7             160             100
V7..............................................             9.6               6              80              50
V8..............................................               8               5              72              45
V9..............................................             9.6               6              80              50
V10.............................................             4.8               3            59.2              37
V11.............................................             6.4               4            68.8              43
----------------------------------------------------------------------------------------------------------------

    About half of all pedestrian fatalities and injuries occur in areas 
where the posted speed limit is 40 mph or lower.\182\ In order to 
mitigate as much of the safety problem as possible, the agency is 
proposing the highest practicable speeds for the upper bound of the 
subject vehicle speed ranges. However, the testing speed may also be 
limited by the ability to test safely and repeatably. The pedestrian 
surrogates NHTSA plans to use for testing have a maximum impact speed 
of 60 km/h (37.5 mph). Therefore, similar to the lead vehicle, the 
highest subject vehicle test speed is determined by the speed 
differential, which is equivalent to the maximum impact speed. The 
maximum test speeds for crossing pedestrian and stationary adult 
scenarios are 60 km/h (37.5 mph), and 65 km/h (40.4 mph) for the 
pedestrian surrogate moving away from vehicle at 5 km/h (3.1 mph) 
scenario, which corresponds to a 60 km/h (37.5 mph) speed 
differential). The 65 km/h (37.5 mph) proposed subject vehicle speed is 
consistent with NCAP's request for comments notice but is 5 km/h (3.1 
mph) greater than the Euro NCAP test speed.\183\
---------------------------------------------------------------------------

    \182\ See Safety Problem section of this notice.
    \183\ Euro NCAP test speeds, https://www.euroncap.com/en/for-engineers/protocols/vulnerable-road-user-vru-protection/, 87 FR 
13470 (Mar. 9, 2022).
---------------------------------------------------------------------------

    When testing at higher speeds and dark lower and dark upper beam 
lighting conditions, PAEB performance was not consistent across the 
tested fleet. The test results, however, showed that for the majority 
of test conditions, at least one of the AEB systems for the MY 2019 and 
2020 test vehicles could perform at the proposed speed ranges. NHTSA 
believes that this aggregate performance of available production AEB 
systems is not indicative of shortcomings in the overall capability of 
AEB technology, but is due to differences in how manufacturers have 
developed perception and decision-making algorithms for specific 
scenarios absent an FMVSS. To afford time to manufacturers to adjust 
the performance of their AEB systems to the proposed requirements, we 
are proposing an extended phase-in period for some test conditions.
    NHTSA observed a similar trend with the deployment of AEB 
technology approximately four years ago, when performance was 
inconsistent in NHTSA's NCAP program for the lead vehicle AEB 
scenarios. AEB systems failed to meet all of the NCAP performance 
levels at that time, but AEB performance quickly improved as 
manufacturers updated and improved software.
    The proposed walking and running speeds of the pedestrian 
surrogates are based on the action of the pedestrian in the test 
scenario. For walking adult scenarios and the running child scenario, 
the pedestrian surrogate speed is 5 km/h (3 mph), and for the running 
adult condition, the pedestrian surrogate speed is 8 km/h (5 mph). 
Research performed by Directorate-General for Research and Innovation 
and published in 2014 identified these speeds as most appropriate for 
PAEB

[[Page 38677]]

testing.\184\ The proposed pedestrian surrogate speeds and the 
stationary pedestrian surrogate condition are also consistent with 
previous NHTSA research, 2019 draft NHTSA PAEB test procedures, and 
Euro NCAP.\185\
---------------------------------------------------------------------------

    \184\ https://cordis.europa.eu/docs/results/285/285106/final1-aspecss-publishable-final-report-2014-10-14-final.pdf at pg. 19.
    \185\ 87 FR 13452 (Mar. 9, 2022), Euro NCAP test speeds, https://www.euroncap.com/en/for-engineers/protocols/vulnerable-road-user-vru-protection/.
---------------------------------------------------------------------------

4. Crossing Path Scenario Testing Speeds
    Two speed ranges are proposed for the crossing path test 
conditions--a range of 10 km/h (6 mph) to 60 km/h (37 mph) for all 
adult pedestrian scenarios in the walking and running conditions 
(pedestrian surrogate moving at 5 km/h (3 mph) and 8 km/h (5 mph), 
respectively), and a range of 10 km/h (6 mph) to 50 km/h (31 mph) for 
the running child (pedestrian surrogate moving at 5 km/h (3 mph)) 
obstructed view scenario.
    The proposed speed ranges for PAEB are based on the results from 
the 2020 NHTSA research. When discussing the research as it relates to 
this notice, the tested vehicles were assigned an identifier as shown 
in Table 22. From the vehicles tested, V3 did not have PAEB 
capabilities in most tests and is not further discussed. Testing 
performed for the 25 percent overlap daylight condition at 16 km/h (10 
mph) and 40 km/h (25 mph) (pedestrian surrogate speed 5 km/h (3 mph)) 
showed that four of the tested vehicles avoided a collision with the 
pedestrian surrogate in all tests conducted and six vehicles avoided 
collision with the pedestrian surrogate in all tests when tested at 40 
km/h (25 mph) (See Table 26).
[GRAPHIC] [TIFF OMITTED] TP13JN23.023

    Figure 13 shows the automatic speed reduction from the testing 
performed at the 25 percent overlap. As an example, if the subject 
vehicle traveling at 40 km/h (25 mph) would approach a stopped object, 
it would need to reduce its speed by 40 km/h (25 mph) to avoid 
collision with the object. However, since the pedestrian surrogate 
continues its movement even after reaching the overlap, the subject 
vehicle does not need to come to a stop to avoid contact with the 
pedestrian surrogate (for an example, see V9 at 40 km/h (25 mph) in 
Figure 13). Different marker shapes are used based on the tested speed 
and shading of the markers to differentiate between the trials where 
the subject vehicle collided with the pedestrian surrogate and the 
successful trials with no contact. As shown in the figures, a 
successful no contact trial is represented by a shaded (filled) shape, 
while the trials with contact are shown as shapes with no shade (no 
fill). The only exception are the trials at 16 km/h (10 mph), where the 
``x'' represents the no contact trials and the ``-'' represents the 
trials with contact.
---------------------------------------------------------------------------

    \186\ https://www.regulations.gov/document/NHTSA-2021-0002-0002.

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

[[Page 38678]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.024

    Even though testing was not performed at 60 km/h (37 mph) for the 
crossing path from the right and 25 percent overlap condition, based on 
the safety need and the consistency of the results observed at 40 km/h 
(25 mph) for the 25 percent overlap, NHTSA has tentatively concluded 
that the proposed performance testing requirements are practicable. The 
agency is currently performing testing at the proposed speed ranges, 
including the 60 km/h (37 mph) speed, to corroborate this conclusion. 
NHTSA is proposing a range for the tested speeds from a low 10 km/h (6 
mph) starting point to ensure system performance at all speeds, as 
opposed to only testing at the highest practicable speeds. As an 
example, the owner's manual of V5 shows the PAEB system working from 5 
km/h (3 mph) up to 120 km/h (75 mph), but when tested, V5 failed to 
avoid collision on all trials at 16 km/h (10 mph). These proposed 
subject vehicle speed ranges are also consistent with Euro NCAP vehicle 
speed ranges and the pedestrian surrogate speeds are consistent with 
both NCAP's latest request for comments notice and Euro NCAP pedestrian 
testing speeds.\188\
---------------------------------------------------------------------------

    \187\ Id.
    \188\ EuroNCAP test speeds, https://www.euroncap.com/en/for-engineers/protocols/vulnerable-road-user-vru-protection/, 87 FR 
13470 (Mar. 9, 2022).
---------------------------------------------------------------------------

    The crossing path from the right at 50 percent overlap test 
scenarios with an adult pedestrian surrogate in the daylight condition 
was performed at a range of speeds from 16 km/h (10 mph) up to 60 km/h 
(37 mph) in NHTSA's 2020 research study. From the 10 relevant vehicles, 
3 avoided collision in all tests up to 50 km/h (31 mph) and one avoided 
collision in all but one test up to 60 km/h (37 mph) (See Table 27).

[[Page 38679]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.025

    Figure 14 shows the speed reduction at various tested speeds. For 
clarity, not all tested speeds are shown. The testing speeds shown 
represent the current PAEB research test procedures test speeds (16 km/
h (10 mph) and 40 km/h (25 mph)) and three other speeds relevant to the 
proposed testing requirements. The three vehicles that avoided impact 
on all tests up to 50 km/h (31 mph) were also able to significantly 
reduce their speeds when tested at 60 km/h (37 mph). This suggests that 
a slight tuning of the AEB systems would allow those systems to avoid 
collision at 60 km/h (37 mph).
[GRAPHIC] [TIFF OMITTED] TP13JN23.026

    In the agency's crossing path from the right with 50 percent 
overlap during dark lighting condition using the vehicle's upper beam 
headlamps, one vehicle avoided collision in all but one test when 
tested at speeds up to 60 km/h (37 mph), and another vehicle avoided 
collision on all tests at speeds above 20 km/h (12 mph) and on most 
tests at 16 km/h (10 mph). A total of four vehicles avoided collision 
either on all or some of the tests at 60 km/h (37 mph) and on

[[Page 38680]]

all tests at 50 km/h (31 mph). Table 28 shows a summary of the tests 
with no contact versus the total number of tests conducted at each test 
speed.
[GRAPHIC] [TIFF OMITTED] TP13JN23.027

    The four vehicles that avoided contact with the test mannequin on 
all or some of the tests at 60 km/h (37 mph) also achieved a speed 
reduction of 30 km/h (19 mph) or more before collision in the tests 
where contact was observed (See Figure 15), which suggests that the 
systems can be adjusted with minimal hardware to the achieve consistent 
collision avoidance at 60 km/h (37 mph).

[[Page 38681]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.028

    When testing the crossing path scenario from the right with 50 
percent overlap at night using the lower beam headlamps, performance 
was generally worse than when testing with the upper beam headlamps or 
during the daylight condition. Only two vehicles were tested at 50 km/h 
(31 mph), one of which avoided contact in two out of four tests and the 
other made contact in every test.\189\ V4 had no contact in four out of 
five tests at 40 km/h (25 mph) and V6 avoided collision in all tests at 
the same speed. From the 10 vehicles tested, 5 had at least one test 
that resulted in collision avoidance at 40 km/h (25 mph). A summary of 
the no contact tests and the total number of tests per vehicle at each 
speed is presented in Table 29.
---------------------------------------------------------------------------

    \189\ In general, based on the testing matrix a vehicle was 
tested at a higher speed only after it had a majority of no contact 
tests at the previous tested speed. Conversely, testing at a 5 km/h 
lower speed was performed only if the vehicle had a least one no 
contact test at the higher speed.
[GRAPHIC] [TIFF OMITTED] TP13JN23.029


[[Page 38682]]


    Of the two vehicles tested at 50 km/h (31 mph), V6 only had tests 
that resulted in contact but was able to achieve a speed reduction of 
33 km/h (21 mph) in two tests and 23 km/h (14 mph) in the other. While 
V4 was able to avoid contact in two tests, it only showed a speed 
reduction of 13 km/h (8 mph) in the tests with contact. The five 
vehicles that had at least one no contact run at 40 km/h (25 mph) also 
achieved a speed reduction of 25 km/h (16 mph) or more (except for one 
test for V9) on the tests which resulted in contact with the test 
mannequin. Speed reduction by vehicle and tested speed for this 
scenario is presented in Figure 16. The observed performance of AEB 
systems when tested under the dark lower beam condition led the agency 
to tentatively conclude that requiring PAEB at speeds up to 60 km/h (37 
mph) is not practicable at this time, but achievable with an adequate 
phase-in. Therefore, for this scenario, as well as other dark testing 
scenarios (see Table 25), in order to afford manufacturers sufficient 
time to adjust the performance of the AEB systems to the proposed test 
requirements, the higher testing speeds are proposed to be implemented 
four years (instead of three years) after the date of publication of 
the final rule. Based on the results of NHTSA's testing, a 10 to 40 km/
h (6 to 25 mph) range is currently practicable (See Figure 16). Tests 
conducted on model year 2021 and 2022 vehicles (available in the docket 
of this proposed rule) and based on current data from NHTSA's 2020 
research testing, NHTSA expects improved performance across all speeds.
[GRAPHIC] [TIFF OMITTED] TP13JN23.030

    Testing for the obstructed running child (child pedestrian 
surrogate travelling at a speed of 5 km/h (3 mph)) scenario with a 50 
percent overlap for the daylight condition found one vehicle that 
avoided collision in all tests up to 50 km/h (31 mph) and in four out 
of five tests from 60 km/h (37 mph). Another vehicle avoided collision 
in all but one test up to 40 km/h (25 mph) and had two tests without 
contact at 50 km/h (31 mph). Table 30 shows the ratio of no contact 
tests to total test by vehicle and tested speed.

[[Page 38683]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.031

    Only V4 was tested at 60 km/h (37 mph), and V4 avoided contact with 
the child mannequin in four out of five tests and achieved a speed 
reduction of more than 50 km/h (31 mph) in the test with contact. Of 
the two vehicles tested at 50 km/h (31 mph), V4 avoided collision in 
all cases. V2 avoided collision in two tests and achieved more than a 
25 km/h (15.5 mph) speed reduction in two tests and a 19 km/h (12 mph) 
speed reduction in a third. Figure 17 shows the speed reduction at the 
test speed for all vehicles tested. Based on the observed performance 
during testing, the agency has tentatively concluded that requiring 
performance at speeds up to 50 km/h (31 mph) is practicable in daylight 
conditions with an adequate phase-in. Concurrent with the development 
of this proposed rule, NHTSA performed PAEB testing on model year 2021 
and 2022 vehicles using the proposed performance requirements and test 
procedures. The results of that testing provide additional support to 
the tentative conclusion that the test conditions, parameters, and 
procedures are practical to conduct and that the proposed requirements 
are practical for manufacturers to achieve. The results of this testing 
are detailed in the PAEB report docketed with this proposed rule.

[[Page 38684]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.032

    NHTSA's testing of the running adult pedestrian scenario 
(pedestrian surrogate travelling at 8 km/h (5 mph)) from the left was 
performed at speeds from 40 km/h (25 mph) to 60 km/h (37 mph) with a 50 
percent overlap during daylight.\190\ The results showed that five 
vehicles made no contact with the pedestrian surrogate in at least one 
test conducted at 60 km/h (37 mph) and all had no contact tests at 50 
km/h (31 mph). One of the five vehicles, V2, avoided contact with the 
test mannequin in all tests at 60 km/h (37 mph). A summary of the tests 
is shown in Table 31.
---------------------------------------------------------------------------

    \190\ Only V5 and V11 were tested at 35 km/h (22 mph) due to 
poor performance at 40 km/h per the test matrix.
[GRAPHIC] [TIFF OMITTED] TP13JN23.033


[[Page 38685]]


    For the 60 km/h (37 mph) tests, the vehicles that did not avoid 
contact still exhibited significant speed reduction. In the one 
instance where V1 collided with the test mannequin, it still achieved a 
speed reduction of 42 km/h (26 mph). V4, V6 and V7 all achieved a speed 
reduction of more than 35 km/h (22 mph) in all instances with contact 
when tested at 60 km/h (37.5 mph). In general, except for V5 and two 
tests (V9 at 40 km/h (25 mph) and V7 at 55 km/h (34 mph)) all vehicles 
achieved significant speed reduction over all tested speeds. Figure 18 
shows the speed reduction at the test speed for all vehicles tested. 
The observed performance of five vehicles avoiding contact with an 
adult surrogate running from the left in tests conducted at 60 km/h (37 
mph) leads the agency to tentatively conclude that requiring 
performance at speeds up to 60 km/h (37 mph) is practicable in daylight 
conditions three years after the publication of a final rule.
[GRAPHIC] [TIFF OMITTED] TP13JN23.034

5. Stationary Scenario Testing Speeds
    NHTSA is proposing a range of subject vehicle travel speeds from 10 
km/h (6 mph) to 55 km/h (34 mph) for the stationary pedestrian along 
path scenario.
    NHTSA's 2020 research testing of this scenario during daylight 
conditions found one vehicle, V1, that avoided collision with the test 
mannequin on all tests but one at 60 km/h (37.5 mph), and two other 
vehicles, V4 and V6, that avoided collision with the test mannequin 
when tested at speeds up to 55 km/h (34 mph). For all the tests up to 
55 km/h (34 mph), V4 avoided collision in all tests and V6 had only one 
collision at 55 km/h (34 mph). Four other vehicles had some no contact 
runs at 40 km/h (25 mph) and 9 of the 10 vehicles had no contact on all 
tests at 16 km/h (10 mph). Table 32 shows a brief overview of test 
results.

[[Page 38686]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.035

    The three vehicles tested at 60 km/h (37 mph), vehicles V1, V4, and 
V6, had considerable speed reduction on the tests where they collided 
with the test mannequin. Where V1 collided with the test mannequin, it 
achieved a speed reduction of 37 km/h (23 mph). Where V6 collided with 
the test mannequin, it showed very consistent results and had a speed 
reduction between 52 km/h (32 mph) and 55 km/h (34 mph) on all three 
tests at 60 km/h (37.5 mph). Similarly, V4 had a speed reduction when 
tested at 60 km/h (37.5 mph) of between 40 km/h (25 mph) and 45 km/h 
(28 mph). The consistent speed reduction results at 60 km/h (37.5 mph) 
reinforce the agency's opinion that minimal tunning is required for 
existing systems to perform at the proposed requirements. Figure 19 
shows the speed reduction at the test speed for all vehicles tested.

[[Page 38687]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.036

    NHTSA upper beam testing using the stationary pedestrian along path 
scenario under dark lighting conditions resulted in one vehicle, V4, 
being able to avoid collision in all tests at speeds up to and 
including 55 km/h (34 mph). The vehicle achieved an average speed 
reduction of 48 km/h (30 mph) in three other tests conducted at 60 km/h 
(37 mph). Two other vehicles avoided collision in all tests at 40 km/h 
(25 mph) (See Table 33).
[GRAPHIC] [TIFF OMITTED] TP13JN23.037

    When tested at 60 km/h, V4 and V11 collided with the test 
mannequin, but were still able to achieve significant speed reduction. 
V4 had very consistent speed reductions ranging from 46 km/h (28.6 mph) 
to 52 km/h (32.3 mph), and V11 achieved a speed reduction of 29 km/h 
(18 mph) and 32 km/h (19.9 mph). When tested at 55 km/h (34 mph), V11 
achieved a speed reduction of 25 km/h (15.5 mph) or more in two tests 
and did not have a large speed reduction on the other test. At 50 km/h 
(31.1 mph), V11 achieved speed reductions of more than 30 km/h (18.6 
mph) when it contacted

[[Page 38688]]

the test mannequin. The other vehicles, where they did not avoid 
contact at 40 km/h (25 mph), had a significant number of tests without 
large speed reductions when they contacted the test mannequin. However, 
V9 at 40 km/h (25 mph) showed an average speed reduction of 23.5 km/h 
(14.6 mph) in the tests where it contacted the test mannequin. Figure 
20 shows the speed reduction at the test speed for all vehicles tested.
[GRAPHIC] [TIFF OMITTED] TP13JN23.038

    Based on the results of the testing, NHTSA has tentatively 
concluded that requiring testing up to 55 km/h (34.2 mph) is feasible 
give the three-year phase-in period after the publication of the final 
rule. At the speeds where some of the tested vehicles made contact, V4, 
with similar hardware, was able to avoid collision. The agency 
anticipates that the other vehicles will be able to avoid contact at 
the proposed testing speed ranges through tunning of their systems to 
the requirements. Concurrent with the development of this proposed 
rule, NHTSA performed PAEB testing on model year 2021 and 2022 vehicles 
using the proposed performance requirements and test procedures. The 
results of that testing provide additional support to the tentative 
conclusion that the test conditions, parameters, and procedures are 
practical to conduct and that the proposed requirements are practical 
for manufacturers to achieve. The results of this testing are detailed 
in the PAEB report docketed with this proposed rule.
    The same vehicle that avoided collision in all tests up to 55 km/h 
(34 mph) under dark conditions with upper beams (V4) also avoided 
collision during all lower beam testing under dark conditions in tests 
up to and including those performed at 50 km/h (31 mph) and during four 
out of five tests at 55 km/h (34 mph). The other tested vehicles 
contacted the test mannequin at speeds on all or most tests when tested 
at speeds above 16 km/h (10 mph). A brief overview of the results for 
the dark lower beam testing for the stationary along path scenario is 
presented in Figure 21 and Table 34.

[[Page 38689]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.039

    V4 had significant and consistent speed reduction of between 45 km/
h (28 mph) and 52 km/h (32 mph) when tested at 60 km/h (37 mph). V4 
also reduced its speed by more than 30 km/h (19 mph) in the one 
instance it contacted the test mannequin when tested at 55 km/h (34 
mph). All other vehicles showed poor results at speeds above 16 km/h 
(10 mph). Three vehicles had no meaningful AEB activation on all tests, 
including 16 km/h (10 mph). V9 was the only vehicle that was able to 
avoid collision on two tests at 40 km/h (25 mph) and had significant 
speed reduction on the other tests at this speed. Figure 21 shows the 
speed reduction at the test speed for all vehicles tested.
[GRAPHIC] [TIFF OMITTED] TP13JN23.040

    Given that V4, using commonly found hardware in AEB systems, was 
able to avoid contact on every test up to 50 km/h (31.1 mph), avoided 
contact on most tests at 55 km/h (34 mph), and achieved significantly 
reduced speed on all other

[[Page 38690]]

higher speed tests (including 65 km/h (60 mph)), the agency has 
tentatively concluded that a no contact requirement for speed ranges up 
to 55 km/h (34 mph) is feasible. The proposed 50 km/h (31 mph) upper 
bound of the range 3 years after final rule publication and 55 km/h (34 
mph) 4 years after publication of the final rule is necessary due to 
pedestrian crashes and fatalities predominantly happening at night and 
at higher speeds (see safety section and PRIA). Concurrent with the 
development of this proposed rule, NHTSA performed PAEB testing on 
model year 2021 and 2022 vehicles using the proposed performance 
requirements and test procedures. The results of that testing provide 
additional support to this tentative conclusion. The results of this 
testing are detailed in the PAEB report docketed with this proposed 
rule.
6. Along Path Scenario Testing Speeds
    The proposed travel speed range for the pedestrian test mannequin 
moving (walking at 5 km/h (3 mph)) along the vehicle's path is from 10 
km/h (6 mph) to 65 km/h (40 mph). NHTSA's 2020 PAEB research testing 
identified three vehicles that avoided contact with the test mannequin 
during all tests performed at 65 km/h (40 mph) (V1 was only tested once 
at 65 km/h (40 mph) where it avoided collision with the test 
mannequin). Of these three vehicles, V6 avoided collision on all tests 
and tested speeds up to 65 km/h (40 mph), V1 avoided collision on all 
but one test up to 65 km/h (40 mph), and V9 avoided collision on all or 
most of the tests up to 65 km/h (40 mph) and avoided collision on 2 out 
of 5 tests at 70 km/h (44 mph). Another vehicle that performed well, 
V4, avoided collision on all tests up to 60 km/h (37.5 mph). Table 35 
provides a breakdown of tests based on the collision avoidance outcome.
[GRAPHIC] [TIFF OMITTED] TP13JN23.041

    V4 had a significant speed reduction of more than 40 km/h on all 
tests when tested at 65 km/h (40 mph). On the test at 50 km/h (31.1 
mph), where V1 collided with the target, it still achieved a speed 
reduction of more than 30 km/h (18.6 mph). Speed reduction for this 
scenario by relevant tested speeds is shown in Figure 22. Based on the 
results from the 2020 testing, NHTSA has tentatively concluded that an 
upper speed bound of 65 km/h (40 mph) is practicable three years after 
the publication of the final rule.

[[Page 38691]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.042

    Testing for the dark upper beam along path pedestrian test 
mannequin moving scenario produced better performance than when testing 
for the dark upper beam stationary scenario. In the along path moving 
scenario, the test mannequin moves away from the subject vehicle at a 
constant speed and continues moving even as the subject vehicle 
decelerates during the AEB event. This has the potential to allow for 
more time and distance to avoid collision. In the agency's research 
testing, one vehicle, V11, avoided collision on all tests at speeds up 
to 50 km/h (31.1 mph), had four out of five test runs at 55 km/h (34 
mph) with no contact, and avoided collision once at 60 km/h (37 mph). 
V4 avoided collision on all tests up to 40 km/h (25 mph), collided once 
out of five tests at 50 km/h (31.1 mph), once out of five tests at 60 
km/h (37 mph), and had one out of four no collision tests at 65 km/h 
(40 mph). Another vehicle, V9, avoided collision on all tests at 50 km/
h (31.1 mph) and avoided collision on a majority of tests at the other 
tested speeds except at 65 km/h (40 mph). A total of five vehicles 
avoided collision on at least some of the tests at speeds up to 50 km/h 
(31.1 mph). Table 36 presents a summary of the test results.

[[Page 38692]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.043

    Figure 23 shows the speed reduction achieved by each vehicle by 
tested speed. For example, when V11 contacted the test mannequin, it 
achieved significant speed reduction. Another vehicle achieving 
significant speed reduction in the tests where it contacted the test 
mannequin across all tested speeds was V4. This vehicle was the only 
one to avoid collision at 65 km/h (40 mph), and even though it only 
avoided collision in one test, it achieved a speed reduction of more 
than 50 km/h (31.1 mph) in all others. The other vehicles did not 
provide consistent results during testing, with a wide range of speed 
reduction values. Because no vehicle was able to avoid collision on all 
tests at the higher speeds, the agency is proposing that the upper 
bound for the speed range for this scenario be 60 km/h (37 mph) three 
years after publication of the final rule and 65 km/h (40 mph) four 
years after publication of the final rule. Concurrent with the 
development of this proposed rule, NHTSA performed PAEB testing on 
model year 2021 and 2022 vehicles using the proposed performance 
requirements and test procedures. The results of that testing provide 
additional support to this tentative conclusion. The results of this 
testing are detailed in the PAEB report docketed with this proposed 
rule.

[[Page 38693]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.044

    Similar to the stationary scenarios, the results from lower beam 
testing in dark lighting conditions for the along path moving test 
condition were less consistent than for the other lighting conditions. 
The tested vehicles were able to avoid contact with the test mannequin 
at higher speeds than in the stationary along path scenario. Two 
vehicles were able to avoid contact with the test mannequin in at least 
one test during tests performed at 60 km/h (37 mph). One vehicle, V4, 
avoided contact with the test mannequin in all tests at 60 km/h (37 
mph) and had two out of five no contact tests at 50 km/h (31.1 mph). 
The other vehicle, V9, had one no contact test out of four at 60 km/h 
(37.5 mph) and a majority of no contact tests at all lower tested 
speeds. The results of the tests are presented in Table 37.
[GRAPHIC] [TIFF OMITTED] TP13JN23.045


[[Page 38694]]


    For the along path moving scenario dark lower beam testing, V4 had 
significant speed reduction when tested at 65 km/h (40 mph) in two test 
runs but failed to activate in a meaningful manner in one test. When 
tested at 60 km/h (37 mph), V9 had two tests with a speed reduction of 
at least 30 km/h (18.6 mph) and one test with no meaningful speed 
reduction. The results from the other tested speeds for V4 and V9 show 
that their AEB systems performed in a similar manner to their 
performance for the upper speeds already discussed. In general, the 
other tested vehicles performed poorly at all speeds except 16 km/h (10 
mph) and did not show consistent speed reduction. Figure 24 shows the 
speed reduction at the test speed for all vehicles tested.
[GRAPHIC] [TIFF OMITTED] TP13JN23.046

    Two vehicles avoided contacting the surrogate in at least one test 
at 60 km/h (37 mph). NHTSA has tentatively concluded that this can be 
achieved across the fleet three years after the publication of a final 
rule. While no vehicle was able to avoid collision at a test speed of 
65 km/h (40 mph), based on the fact that V4 and V9 (equipped with AEB 
systems with hardware in common) were able to avoid collision in at 
least one test at 60 km/h (37 mph), the agency tentatively concludes 
that four years after the publication of the final rule, vehicles will 
be able to achieve no contact at 65 km/h (40 mph). The need for testing 
at higher speeds in dark lighting conditions is dictated by the safety 
need, since as previously discussed, pedestrian fatalities 
predominantly occur during dark conditions and at higher speeds. 
Concurrent with the development of this proposed rule, NHTSA performed 
PAEB testing on model year 2021 and 2022 vehicles using the proposed 
performance requirements and test procedures. The results of that 
testing provide additional support to this tentative conclusion. The 
results of this testing are detailed in the PAEB report docketed with 
this proposed rule.
7. PAEB Darkness Testing
    During agency testing, PAEB system performance was not consistent 
for some of the proposed lighting conditions and speeds. However, the 
agency has tentatively concluded that testing in dark lighting 
conditions is necessary, and vehicles can be designed and produced to 
avoid collisions in all dark lighting test conditions given an adequate 
phase-in period. This is consistent with recent IIHS tests finding that 
existing systems can perform in the dark-lighted conditions regardless 
of their IIHS headlamp ratings.191 192 NHTSA tentatively 
concludes that PAEB system performance is improving, and the latest 
PAEB systems are already able to perform much better under the proposed 
lighting conditions than previous iterations of the systems.\193\ 
Concurrent with the development of this proposed rule, NHTSA performed 
PAEB testing on model year 2021 and 2022 vehicles using the proposed

[[Page 38695]]

performance requirements and test procedures. The results of that 
testing provide additional support to the tentative conclusion that the 
test conditions, parameters, and procedures are practical to conduct 
and that the proposed requirements are practical for manufacturers to 
achieve. The results of this testing are detailed in the PAEB report 
docketed with this proposed rule.
---------------------------------------------------------------------------

    \191\ IIHS dark light press release: https://www.iihs.org/news/detail/pedestrian-crash-avoidance-systems-cut-crashes--but-not-in-the-dark.
    \192\ Id.
    \193\ ``The better-performing systems are too new to be included 
in our study of real-world crashes . . . This may indicate that some 
manufacturers are already improving the darkness performance of 
their pedestrian AEB systems.'' Id.
---------------------------------------------------------------------------

    When tested, the observed crash avoidance performance of the tested 
PAEB systems was best for the daylight and upper beam conditions. Table 
38 shows the maximum speeds at which the test vehicles did not collide 
with the test mannequin either on all trials or at least one trial. 
Based on the previously detailed results of the 2020 testing, the 
agency tentatively concludes that three years after final rule 
publication, consistent performance is possible for the darkness 
testing conditions through further tuning of existing AEB systems 
without major hardware upgrades. The additional year of phase-in for 
higher speed darkness performance requirements would allow time for 
systems that currently do not perform consistently to be adjusted or 
tuned to the proposed requirements. NHTSA has also concluded that the 
crossing path running child from the right scenario and the running 
adult from the left scenario with dark lower beam or upper beam are not 
a practicable requirement at this time.

                                            Table 38--PAEB: Highest Speed at Which a Vehicle Avoided Contact on at Least One Trial Versus All Trials
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                         Crossing path--right,  50 percent overlap                            Stationary                                          Along-path
        Lighting condition        --------------------------------------------------------------------------------------------------------------------------------------------------------------
                                       At least one trial             All trials             At least one trial            All trials            At least one trial            All trials
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Daylight.........................  60 km/h..................  60 km/h..................  60 km/h..................  55 km/h.................  70 km/h.................  65 km/h.
Dark, Upper Beam.................  60 km/h..................  60 km/h..................  55 km/h..................  55 km/h.................  65 km/h.................  50 km/h.
Dark, Lower Beam.................  50 km/h..................  40 km/h..................  55 km/h..................  50 km/h.................  60 km/h.................  60 km/h.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

G. Alternatives to No-Contact Performance Test Requirement

    NHTSA is considering two alternatives to a no-contact requirement 
for both the lead vehicle and pedestrian performance test requirements.
    The first alternative would be to permit low speed contact in 
NHTSA's on-track testing. Under this alternative, the subject vehicle 
would meet the requirements of the standard if it applied the brakes 
automatically in a way that reduced the impact speed either by a 
defined amount or to a maximum collision speed. The speed at which the 
collision would be allowed to occur would be low enough that the crash 
would be highly unlikely to be fatal or to result in serious injury.
    NHTSA seeks comment on the appropriateness of such a requirement, 
any factors to consider surrounding such a performance level, and what 
the appropriate reduction in speed or maximum impact speed should be. 
NHTSA has considered this alternative separately for the lead vehicle 
requirement and the pedestrian requirement and came to the same 
tentative conclusion to propose a no contact performance requirement 
for on-track testing in each case. However, NHTSA seeks comment on this 
level of performance separately for the lead vehicle and pedestrian 
requirements because the safety implications of low-speed impacts are 
different for each of these two crash types.
    NHTSA also seeks comment on the potential consequences on testing 
if vehicle contact were allowed. NHTSA has extensive experience with 
performing AEB evaluations and has observed that it is possible for 
even relatively low-speed collisions with the lead vehicle test device 
or pedestrian test mannequin to potentially damage the subject vehicle. 
For instance, if a test vehicle were to strike the lead vehicle test 
device, even at a low speed, sensors on the vehicle could become 
misaligned, and subsequent tests might not be representative of the 
vehicle condition at time of first sale. For instance, cameras or radar 
devices could become misaligned. Additionally, striking the vehicle 
test device or pedestrian test mannequin might prematurely degrade the 
appearance of the device and modify its specifications, including in 
ways that are not immediately observable. For example, damage to the 
test device might affect the radar cross section that requires a long 
verification procedure to discover. NHTSA is concerned that any 
performance test requirement that allows for vehicle contact could 
result in expensive or time-consuming interruptions to repair the 
subject vehicle or test device to ensure repeatable testing. NHTSA 
seeks comment on this concern.
    The second alternative the agency is considering is a no contact 
requirement that permits the vehicle to use multiple runs to achieve 
the performance test requirements. For example, NHTSA's CIB and DBS 
NCAP test performance criteria currently specify that the speed 
reduction requirements for each test scenario must be met in at least 5 
out of 7 tests runs. This approach would provide a vehicle more 
opportunities to achieve the required performance and the agency more 
statistical power in characterizing the performance of the vehicle. The 
agency seeks comment on the number of repeated tests for a given test 
condition and on potential procedures for repeated tests. The agency 
also seeks comment on the merits of permitting a vehicle that fails to 
activate its AEB system in a test to be permitted additional repeat 
tests, including a repeat test process similar to that in the recent 
revisions to UN ECE Regulation No. 151.\194\ Finally, the agency seeks 
comment on whether there should be additional tests performed in the 
event no failure occurs on an initial test for each series.
---------------------------------------------------------------------------

    \194\ Section 6.10.1 of UN ECE Regulation No. 151 provides 
robustness criteria that specifies that each test condition is 
performed two times. If vehicle does not meet the required 
performance criteria in one of the two test runs, a third test may 
be conducted. A test scenario is considered passed if the required 
performance is met in two test runs. However, the total number of 
failed test runs cannot exceed 10 percent for the lead vehicle and 
pedestrian tests.
---------------------------------------------------------------------------

    In the request for comments on upgrades to NCAP, NHTSA sought 
comment on an approach that permitted repeated trials for collision 
avoidance requirements if an impact occurred with a minimum speed 
reduction of at least 50 percent.\195\ This approach would not permit 
repeated trials if an impact occurred above certain speeds during the 
test series conducted for a given test scenario/condition. NHTSA seeks 
comment on the implications if NHTSA were to require a partial speed 
reduction, such as 50 percent, in

[[Page 38696]]

combination with an alternate approach for multiple trials. For 
example, if a collision occurs and the relative impact speed is less 
than 50 percent of the initial speed, the test is repeated. If a 
collision occurs again, the subject vehicle would be noncompliant. 
Alternatively, even if the subject vehicle avoids a collision, NHTSA 
could test again. The number of repeated tests needed to meet the 
performance test requirement would be established by NHTSA. If the 
agency were to consider such an approach, what should be the required 
speed reduction (e.g., 50 percent, 75 percent, etc.) and how many tests 
must follow without a collision?
---------------------------------------------------------------------------

    \195\ 87 FR 13452 March 9, 2022.
---------------------------------------------------------------------------

H. False Activation Requirement

    NHTSA is also proposing to include two scenarios in which braking 
is not warranted. These tests are sometimes referred to as ``false-
positive'' tests. AEB systems need to be able to differentiate between 
a real threat and a non-threat to avoid false activations. NHTSA is 
concerned that false activation events may introduce hard braking 
situations when such actions are not warranted, potentially causing 
rear-end crashes. The proposed false activation tests establish only a 
baseline for system functionality. They are by no means comprehensive, 
nor sufficient to eliminate susceptibility to false activations. 
Rather, the proposed tests are a means to establish minimum 
performance. NHTSA expects that vehicle manufacturers will design AEB 
systems to thoroughly address the potential for false activations.\196\ 
Vehicles that have excessive false positive activations may pose an 
unreasonable risk to safety and may be considered to have a safety-
related defect. Previous implementations of other technologies have 
shown that manufacturers have a strong incentive to mitigate false 
positives and are successful even in the absence of specific 
requirements.
---------------------------------------------------------------------------

    \196\ From the NCAP request for comments notice ``Specifically, 
the Alliance stated that vehicle manufacturers will optimize their 
systems to minimize false positive activations for consumer 
acceptance purposes, and thus such tests will not be necessary. 
Similarly, Honda stated that vehicle manufacturers must already 
account for false positives when considering marketability and 
HMI.'' 87 FR 13452 (Mar. 9, 2022) at 13460.
---------------------------------------------------------------------------

    The two proposed false activation scenarios are the steel trench 
plate and the vehicle pass-through test scenarios. Both of these tests 
will include acceleration pedal release and testing both with and 
without manual braking, similar to testing with a stopped lead vehicle. 
NHTSA is proposing that, during each test trial, the subject vehicle 
accelerator pedal will be released either when a forward collision 
warning is given or at a headway that corresponds to a time-to-
collision of 2.1 seconds, whichever occurs earlier. For tests where 
manual braking occurs, the brake is applied at a headway that 
corresponds to a time-to-collision of 1.1 seconds.
1. Steel Trench Plate False Activation Scenario
    The steel trench plate test was introduced in the NHTSA NCAP test 
procedures to assess whether a false positive condition could be 
identified and consistently utilized.\197\ In the steel trench plate 
test, a steel plate commonly used in road construction is placed on the 
surface of a test track. The steel plate presents no imminent danger, 
and the subject vehicle can safely travel over the plate without harm.
---------------------------------------------------------------------------

    \197\ CIB Non-Threatening Driving Scenarios (DOT HS 811 795); 
NHTSA CIB--Crash Imminent Braking test procedure- https://www.regulations.gov/document/NHTSA-2015-0006-0025, https://www.regulations.gov/document/NHTSA-2015-0006-0176.
---------------------------------------------------------------------------

    In the steel trench plate false activation scenario, a subject 
vehicle traveling at 80 km/h (50 mph) encounters a secured 2.4 m (7.9 
ft) wide by 3.7 m (12.1 ft) long steel by 25 mm (1 in) thick ASTM A36 
steel plate placed flat in the subject vehicle's lane of travel, and 
centered in the travel path, with its short side toward the vehicle 
(long side transverse to the path of the vehicle). The AEB system must 
not engage the brakes to create a peak deceleration of more than 0.25g 
additional deceleration than any manual brake application generates (if 
used). The basic setup for the steel trench plate false positive test 
is shown in Figure 25.
[GRAPHIC] [TIFF OMITTED] TP13JN23.048

2. Pass-Through False Activation Scenario
    The pass-through test, as the name suggests, simulates the subject 
vehicle encountering two vehicles outside of the subject vehicle's path 
that do not present a threat to the subject vehicle. The test is 
similar to the UNECE R131 and UNECE R152 false reaction tests.\198\ In 
the pass-through scenario, two VTDs are positioned in the adjacent 
lanes to the left and right of the subject vehicle's travel path, while 
the lane in which the subject vehicle is traveling is free of 
obstacles.
---------------------------------------------------------------------------

    \198\ U.N. Regulation No. 131 (Feb. 27, 2020), available at 
https://unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2015/R131r1e.pdf; U.N. Regulation No. 152, E/ECE/TRANS/505/Rev.3/Add.151/
Amend.1 (Nov. 4, 2020), available at https://unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2020/R152am1e.pdf.
---------------------------------------------------------------------------

    The two stopped VTDs are positioned parallel to each other and 4.5 
m (14.8 ft) apart in the two adjacent lanes to that of the subject 
vehicle (one to the left and one to the right with a 4.5 m (14.8 ft) 
gap between them). The 4.5 m (14.8 ft) gap represents a typical travel 
lane of about 3.6 m (11.8 ft) plus a reasonable distance at which a 
vehicle would be stationary within the adjacent travel lanes.\199\ 
Similar to the steel trench plate false activation scenario, the AEB 
must not engage the brakes to create a peak deceleration of more than 
0.25g beyond any manual braking. In Figure 26, a basic setup for the 
test is shown.
---------------------------------------------------------------------------

    \199\ Federal Highway Administration (Oct. 15, 2014), Range of 
lane widths for travel lanes and ramps, https://safety.fhwa.dot.gov/geometric/pubs/mitigationstrategies/chapter3/3_lanewidth.cfm.

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[[Page 38697]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.049

3. Potential Alternatives to False Activation Requirements
    As alternatives to these two false activation tests, NHTSA is 
considering removing the false activation tests completely, requiring a 
robust documentation process or specifying a data storage requirement. 
First, NHTSA seeks comment on the anticipated impacts on safety and the 
certification burden if the agency were to finalize a rule that did not 
contain one or both of the proposed false positive tests. 
Alternatively, NHTSA is considering requiring that manufacturers 
maintain documentation demonstrating that robust process standards are 
followed specific to the consideration and suppression of false 
application of AEB in the real world. Other industries where safety-
critical software-controlled equipment failures may be life-threatening 
(e.g., aviation \200\ and medical devices) \201\ are regulated via 
process controls ensuring that good software development engineering 
practices are followed. This approach recognizes that system tests are 
limited in their ability to evaluate complex and constantly changing 
software-driven control systems. Software development lifecycle 
practices that include risk management, configuration management, and 
quality assurance processes are used in various safety-critical 
industries. ISO 26262, ``Road vehicles--Functional safety,'' ISO 21448, 
``Safety of the Intended Functionality (SOTIF),'' and related 
standards, are examples of an approach for overseeing software 
development practices. Process standards could be a robust approach to 
the regulation of false positives because false activation of braking 
is a complex engineering problem with multiple factors and conditions 
that must be considered in the real world. The agency seeks public 
comment on all aspects of requiring manufacturers to document that they 
have followed process standards in the consideration of the real-world 
false activation performance of the AEB system.
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    \200\ 14 CFR 33.201 (a) The engine must be designed using a 
design quality process acceptable to the FAA, that ensures the 
design features of the engine minimize the occurrence of failures, 
malfunctions, defects, and maintenance errors that could result in 
an IFSD, loss of thrust control, or other power loss.
    \201\ 21 CFR 820.30(a)(1) Each manufacturer of any class III or 
class II device, and the class I devices listed in paragraph (a)(2) 
of this section, shall establish and maintain procedures to control 
the design of the device in order to ensure that specified design 
requirements are met.
---------------------------------------------------------------------------

    Finally, NHTSA is considering requiring targeted data recording and 
storage of significant AEB activations. These data could then be used 
by manufacturers to improve system performance, or by the agency to 
review if a particular alleged false activation was part of a safety 
defect investigation. NHTSA is considering a requirement that an AEB 
event that results in a speed reduction of greater than 20 km/h (12 
mph) activate the recording and storage of the following key 
information: date, time, engine hours (i.e., the time as measured in 
hours and minutes during which an engine is operated), AEB activation 
speed, AEB exit speed (i.e., vehicle speed at which the AEB is 
completely released), AEB exit reason (e.g., driver override with 
throttle or brake, or system decision), location, and camera image 
data. This information could be used by investigators to analyze the 
source of the activation and determine if there was a false activation. 
Such data would need to be accessible by the agency and potentially by 
the vehicle operator for a full and transparent analysis. The agency 
seeks comment on all aspects of this data collection approach as an 
alternative to false activation testing, including whether this list of 
potential elements is incomplete, overinclusive, or impractical.

I. Malfunction Detection Requirement

    NHTSA is proposing that AEB systems must continuously detect system 
malfunctions. If an AEB system detects a malfunction that prevents it 
from performing its required safety function, the vehicle would provide 
the vehicle operator with a warning. The warning would be required to 
remain active as long as the malfunction exists while the vehicle's 
starting system is on. NHTSA would consider a malfunction to include 
any condition in which the AEB system fails to meet the proposed 
performance requirements. NHTSA is proposing that the driver must be 
warned in all instances of component or system failures, sensor 
obstructions, environmental limitations (like heavy precipitation), or 
other situations that would prevent a vehicle from meeting the proposed 
AEB performance requirements. While NHTSA is not proposing the 
specifics of the telltale, NHTSA anticipates that the characteristics 
of the alert will be documented in the vehicle owner's manual and 
provide sufficient information to the vehicle operator to identify it 
as an AEB malfunction.
    NHTSA is considering requirements pertaining to specific failures 
and including an accompanying test procedure. For instance, NHTSA could 
develop or use available tests that specify examples of how an AEB 
system might be placed in a malfunctioning state, such as disconnecting 
sensor wires, removing fuses, misaligning or covering sensors.
    NHTSA is considering minimum requirements for the malfunction 
indication to standardize the means by which the malfunction is 
communicated to the vehicle operator. Malfunctions of

[[Page 38698]]

an AEB system are somewhat different than other malfunctions NHTSA has 
considered in the past. While some malfunctions may be similar to other 
malfunctions NHTSA has considered in FMVSSs because they require repair 
(loose wires, broken sensors, etc.), others are likely to resolve 
without any intervention, such as low visibility due to environmental 
conditions or blockages due to build-up of snow, ice, or loose debris.
    NHTSA is considering requiring that the malfunction indicator 
convey the actions that a driver should take when an AEB malfunction is 
detected. NHTSA seeks comment on the potential advantages of specifying 
test procedures that would describe how the agency would test a 
malfunction indicator and on the level of detail that this regulation 
should require for a malfunction indicator. Additionally, NHTSA is 
considering requiring more details for the indicator itself, such as a 
standardized appearance (e.g., color, size, shape, illuminance). NHTSA 
seeks comment on the need and potential safety benefits of requiring a 
standardized appearance for the malfunction indicator and what 
standardized characteristics would achieve the best safety outcomes. 
NHTSA seeks comment on the use of an amber FCW warning indicator visual 
icon as the malfunction indicator.
    NHTSA anticipates driving situations in which AEB activation may 
not increase safety and in some rare cases may increase risk. For 
instance, an AEB system in which sensors have been compromised because 
of misalignment, frayed wiring, or other partial failure, could provide 
the perception system with incomplete information that is then 
misinterpreted and causes a dangerous vehicle maneuver to result. In 
other instances, such as when a light vehicle is towing a trailer with 
no independent brakes, or brakes that do not include stability control 
functions, emergency braking may cause jack-knifing, or other dangerous 
outcomes. NHTSA is considering restricting the automatic deactivation 
of the AEB system generally and providing a list of situations in which 
the vehicle is permitted to automatically deactivate the AEB or 
otherwise restrict braking authority granted to the AEB system.
    In addition to these, NHTSA is considering allowing the AEB system 
to be placed in a nonfunctioning mode whenever the vehicle is placed in 
4-wheel drive low or when ESC is turned off, and whenever equipment 
such as a snowplow is attached to the vehicle that might interfere with 
the AEB system's sensors or perception system. The malfunction 
indication requirements would apply in any such instance. NHTSA seeks 
comment on the permissibility of automatic deactivation of the AEB 
system and under which situations the regulation should explicitly 
permit automatic deactivation of the AEB system.

J. AEB System Disablement

    This proposed rule would not permit manual AEB system disablement 
at any speed above the proposed 10 km/h (6 mph) minimum speed threshold 
above which the AEB system must operate. NHTSA seeks comment on whether 
manual deactivation for an AEB system should be allowed at speeds above 
10 km/h (6 mph), similar to what is allowed for ESC systems in FMVSS 
No. 126.\202\ NHTSA seeks comment on the appropriate performance 
requirements if the standard were to permit the installation of a 
manually operated deactivation switch. Such requirements might include 
limitations such that the default position of the switch be ``AEB ON'' 
with each cycle of the starting system, or the deactivation 
functionality could be limited to specific speeds.
---------------------------------------------------------------------------

    \202\ 49 CFR 571.126 S5.4.
---------------------------------------------------------------------------

K. AEB System Performance Information

    This proposed rule has no requirements that the vehicle 
manufacturer provide information to vehicle operators about how the AEB 
system works. NHTSA is considering a requirement that manufacturers 
provide information describing the conditions under which the AEB 
system can avoid collisions, warning drivers that the AEB system is an 
emergency system and not designed for typical braking situations, and 
specifying the conditions under which the AEB system is not likely to 
prevent a collision. NHTSA seeks comment on the potential safety 
impacts of requiring such information be provided to vehicle operators 
and any costs associated with such an information requirement.

VII. AEB Test Procedures

    To determine compliance with the proposed requirements, NHTSA 
proposes to test AEB systems on a test track using specified procedures 
and conditions. To establish the appropriate test procedures and 
conditions, the agency considered several factors, including the 
expected real-world conditions under which AEB systems need to operate 
to effectively reduce crash risk, the procedures and conditions that 
provide a high degree of test repeatability and reproducibility, the 
procedures and conditions needed for safe testing, procedures and 
conditions that are within the practical operating range of AEB 
systems, the consistency between FMVSS and NCAP test procedures and 
conditions, and harmonization with test procedures and conditions in 
international AEB regulations and other test programs such as NCAP.
    NHTSA's 2014 draft CIB and DBS research test procedures are the 
original basis for the proposed AEB-Lead Vehicle test procedures 
included in this NPRM.203 204 Similarly, NHTSA's 2019 draft 
research test procedure for PAEB systems is the original basis for the 
PAEB test procedures in this NPRM.\205\ Those documents reflect the 
agency's experience researching automatic braking systems at the NHTSA 
Vehicle Research and Test Center. They also are the main source of 
NHTSA's current NCAP test procedures for AEB-equipped vehicles.
---------------------------------------------------------------------------

    \203\ National Highway Traffic Safety Administration (2014, 
August), Crash imminent brake system performance evaluation (working 
draft). Available at: https://www.regulations.gov/document/NHTSA-2012-0057-0038.
    \204\ National Highway Traffic Safety Administration (2014, 
August), Dynamic Brake Support Performance Evaluation (working 
draft). Available at: https://www.regulations.gov/document/NHTSA-2012-0057-0038.
    \205\ 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.
---------------------------------------------------------------------------

    To the extent possible, the proposed test conditions (such as 
environmental conditions, vehicle set-up, etc.) are the same in all 
tests unless otherwise specified. This provides for simplified, 
consistent test procedures and conditions.

A. AEB System Initialization

    NHTSA is proposing that AEB systems will be initialized before each 
series of performance tests to ensure the AEB system is in a ready 
state for each test trial. The electronic components of an AEB system, 
including sensors and processing modules, may require a brief interval 
following each starting system cycle to reset to their default 
operating state. It also may be necessary for an AEB-equipped vehicle 
to be driven at a minimum speed for a period of time prior to testing 
so that the electronic systems can self-calibrate to a default or 
baseline condition, and/or for the AEB system to become active. The 
proposed initialization procedure specifies that, once the test vehicle 
starting system is cycled on, it will remain on for at least one minute 
and the vehicle is driven at a forward speed of at least 10 km/h (6 
mph) before any performance trials

[[Page 38699]]

commence. This procedure also ensures that no additional driver actions 
are needed for the AEB system to be in a fully active state.

B. Travel Path

    To maximize test repeatability, the travel path in each of the 
proposed test scenarios is straight rather than curved. A straight path 
simplifies vehicle motion and eliminates the more complex vehicle 
control needed for curve-following and which is likely to be less 
repeatable. NHTSA's draft research test procedures also specify 
straight-line vehicle tests, and other AEB test programs including 
NHTSA's NCAP employ a straight travel path.
    The intended travel path is the target path for a given test 
scenario. For the proposed AEB tests as conducted by NHTSA for NCAP, 
the travel path has been programmed into a robotic steering controller, 
and a global positioning system (GPS) has been used to follow the 
intended path. The proposed text does not limit the method for steering 
the subject vehicle and as such any method including a human driver 
could be used by the agency during compliance testing. Regardless of 
the steering method, the positional tolerance would be maintained for a 
valid test. The travel path is identified by the projection onto the 
road surface of the frontmost point of the subject vehicle that is 
located on its longitudinal, vertical center plane. The subject 
vehicle's actual travel path is recorded and compared to the intended 
path. For test repeatability, the subject vehicle's actual travel path 
is measured during each test run and will not deviate more than a 
specified distance from the intended path.
    NHTSA is proposing that the intended subject vehicle travel path be 
coincident with the center of a test lane whenever there are two edge 
lines marking a lane on the test track surface. If there is only one 
lane line (either a single or double line) marked on the test track, 
the vehicle path will be parallel to it and offset by 1.8 m (6 ft) to 
one side (measured from the inside edge of the line). Modern vehicles 
equipped with AEB often are equipped with other advanced driver 
assistance systems, such as lane-centering technology, which detects 
lane lines and which might be triggered if the travel path diverges 
substantially from the center of a marked test lane, potentially 
leading to unrepeatable results. These specifications reflect the 
agency's NCAP tests for AEB.206 207 
208
---------------------------------------------------------------------------

    \206\ National Highway Traffic Safety Administration (2014, 
August), Crash imminent brake system performance evaluation (working 
draft). Available at: https://www.regulations.gov/document/NHTSA-2012-0057-0038.
    \207\ National Highway Traffic Safety Administration (2014, 
August), Dynamic Brake Support Performance Evaluation (working 
draft). Available at: https://www.regulations.gov/document/NHTSA-2012-0057-0038.
    \208\ National Highway Traffic Safety Administration (2013, 
February), Lane departure warning system confirmation test and lane 
keeping support performance documentation. See https://www.regulations.gov, Docket No. NHTSA-2006-26555-0135.
---------------------------------------------------------------------------

C. Subject Vehicle Preparation

    NHTSA is proposing that there be no specific limitations on how a 
subject vehicle may be driven prior to the start of a test trial. As 
long as the specified initialization procedure is executed, a subject 
vehicle may be driven under any conditions including any speed and 
direction, and on any road surface, for any elapsed time prior to 
reaching the point where a test trial begins. This is because the 
manner in which a subject vehicle is operated prior to a crash imminent 
situation should not compromise or otherwise affect the functionality 
of the AEB system. Also, ancillary subject vehicle operation on and 
around a test track will vary depending on exigencies of testing such 
as test lane location. For example, a subject vehicle may need to be 
driven across an unmarked section of pavement, be maneuvered using 
unspecified steering, braking, and accelerator inputs, and/or be driven 
in reverse in order to reach the start position for a test trial.

D. Subject Vehicle Tolerance Specifications

    NHTSA is proposing that the subject vehicle speed would be 
maintained within a tolerance range of 1.6 km/h (1.0 mph) of the chosen test speed between the beginning of a test 
and the onset of the forward collision warning. For test repeatability, 
subject vehicle speed would be as consistent as possible from run to 
run. Subject vehicle speed determines the time-to-collision, which is a 
critical variable in AEB tests. In NHTSA's experience, subject vehicle 
speed can be reliably controlled within the 1.6 km/h 
(1.0 mph) tolerance range, and speed variation within that 
range yields consistent test results. A smaller speed tolerance is 
unnecessary for repeatability and burdensome as it may result in a 
higher test rejection rate without any greater assurance of accuracy of 
the AEB system's test track performance. This speed tolerance also is 
the same as that specified in the agency's NCAP tests for AEB systems.
    NHTSA is proposing that, during each test trial, the subject 
vehicle accelerator pedal will be released when a forward collision 
warning is given or when the AEB system first engages, whichever is 
sooner. Input to the accelerator pedal after AEB has engaged will 
potentially interfere with the system and may override the automatic 
braking. Therefore, it is necessary to fully release the subject 
vehicle's accelerator pedal. The proposed procedure states that the 
accelerator pedal is released at any rate and is fully released within 
500 milliseconds. This ensures consistent release of the accelerator to 
eliminate any interference with AEB engagement and improve test 
repeatability. This procedure also better reflects real-world 
conditions because a driver's first reaction to a forward collision 
warning is likely to be accelerator release.\209\ This manner of 
accelerator pedal control is the same as specified in the agency's NCAP 
test procedures for AEB systems.
---------------------------------------------------------------------------

    \209\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
---------------------------------------------------------------------------

    The accelerator pedal release can be omitted from tests of vehicles 
with cruise control actively engaged because there is no driver input 
to the accelerator pedal in that case. The AEB performance requirements 
in this proposal are the same for vehicles with and without cruise 
control engaged, and AEB systems must provide an equivalent level of 
crash avoidance or mitigation whether or not cruise control is active.
    NHTSA is proposing that the subject vehicle yaw rate does not 
exceed 1.0 deg/s prior to onset of when the subject vehicle 
forward collision warning is given or the subject vehicle AEB system 
first engages, whichever is sooner. The agency proposes to adopt this 
tolerance for test repeatability. A 1.0 deg/s yaw rate 
tolerance, which is the most stringent value among the yaw rate limits 
specified in the agency's NCAP test procedures for AEB.
    NHTSA is proposing that the travel path of the subject vehicle does 
not deviate more than 0.3 m (1.0 ft) laterally from the centerline of 
the lead vehicle. For consistent test conduct, it is necessary to 
maintain close alignment between the subject vehicle path and the lead 
vehicle path. Significant misalignment of the travel paths may change 
detection characteristics such as range and relative direction, 
potentially resulting in test-to-test inconsistency. Therefore, the 
agency proposes to use the tolerance requirement of 0.3 m (1.0 ft) for 
the subject vehicle's lateral position, which is more stringent than

[[Page 38700]]

the lateral tolerance used in NHTSA's NCAP test procedures for AEB, but 
less stringent than the lateral tolerance specified in NHTSA's NCAP 
test procedures for PAEB. This tolerance is consistent with the SAE 
International recommended practice for AEB. In this proposal, the same 
lateral tolerance 0.3 m (1.0 ft) would be used for both lead vehicle 
AEB and PAEB.

E. Lead Vehicle Test Set Up and Tolerance

    NHTSA is proposing that the speed of the lead vehicle would be 
maintained within a tolerance of 1.6 km/h (1.0 
mph) during slower-moving tests and during decelerating lead vehicle 
tests until the lead vehicle initiates its deceleration. Like the 
subject vehicle speed, the speed of the lead vehicle (i.e., the target 
vehicle) is a key parameter that directly influences TTC and other test 
outcomes. Results from a series of tests with run-to-run speed 
variations outside this tolerance range may be inconsistent. Therefore, 
for lead vehicle speed, the agency is proposing to use the same 
tolerance of 1.6 km/h (1.0 mph) specified for 
the subject vehicle speed, which also reflects the tolerance value used 
for NHTSA's NCAP AEB tests.
    NHTSA is proposing that the lead vehicle would not diverge 
laterally more than 0.3 m (1.0 ft) from the intended travel path. This 
tolerance applies to both the slower-moving and decelerating lead 
vehicle test scenarios (for the stopped lead vehicle scenario, the lead 
vehicle is stationary and is centered on the projected subject vehicle 
travel path). If the lead vehicle's lateral position deviates 
significantly from the intended travel path, its alignment within the 
field of view of the forward sensors of the subject vehicle will be 
off-center, which can contribute to test series variability. The 0.3 m (1.0 ft.) tolerance for the lead vehicle's 
lateral position is the same tolerance specified for the subject 
vehicle's lateral position, which is consistent with the tolerance used 
in the SAE recommended practice for AEB testing.\210\
---------------------------------------------------------------------------

    \210\ SAE International (2017), Automatic Emergency Braking 
(AEB) System Performance Testing (SAE J3087).
---------------------------------------------------------------------------

    Controlled lead vehicle deceleration is essential for repeatable 
decelerating lead vehicle AEB testing because the reaction of the 
subject vehicle depends largely on the position and motion of the lead 
vehicle. NHTSA is proposing that the lead vehicle will achieve the 
specified deceleration within 1.5 seconds of the onset of lead vehicle 
braking. Over this time period, the overall deceleration will be lower 
than the target, but will rise over time, allowing for easier test 
completion. This lead-in time also makes it easier for the test to be 
performed while not making the test harder to pass. The lead vehicle 
will maintain this deceleration until 250 milliseconds prior to the 
vehicle coming to rest. Over these 250 milliseconds the vehicle 
dynamics do not reflect the overall dynamics of the test, and any 
acceleration data recorded is dismissed. This deceleration profile is 
consistent with NHTSA's NCAP test procedures and SAE's industry 
recommended practice for AEB systems.\211\
---------------------------------------------------------------------------

    \211\ SAE International (2017), Automatic Emergency Braking 
(AEB) System Performance Testing (SAE J3087).
---------------------------------------------------------------------------

F. Test Completion Criteria for Lead Vehicle AEB Tests

    For lead vehicle tests, NHTSA is proposing test-completion criteria 
to clearly establish the point at which a test trial has concluded. For 
all lead vehicle scenarios, each test run is considered complete 
immediately when the subject vehicle makes contact with the lead 
vehicle. In the case of stopped or decelerating lead vehicle tests, 
each test run also would be considered complete when the subject 
vehicle comes to a complete stop without impact. For slower-moving lead 
vehicle tests, the test is complete when the subject vehicle's speed is 
less than the lead vehicle speed. These test completion criteria are 
important in identifying a pass-fail outcome for AEB-equipped light 
vehicles. These criteria also are needed to limit consideration of 
vehicle motion or behavior after there is no longer a foreseeable 
collision with the lead vehicle.

G. PAEB Test Procedures and Tolerance

    For PAEB testing, NHTSA proposes using the same general procedures 
described above, as applicable, including procedures for subject 
vehicle speed, yaw rate, travel path, lateral tolerance, subject 
vehicle accelerator pedal release.
    Overlap refers to the test mannequin's potential impact point 
measured horizontally across the front end of the subject vehicle. It 
identifies the point on the subject vehicle that would contact a test 
mannequin that is within the subject vehicle travel path if the subject 
vehicle were to maintain its speed without braking. NHTSA proposes 
using an overlap value of either 50 percent, the midpoint of the 
subject vehicle's frontal surface, or 25 percent indicating the point 
that is one-quarter of the subject vehicle width from the right side of 
the subject vehicle. NHTSA is proposing a 0.15 m (0.5 ft) overlap 
tolerance, which provides a high degree of test repeatability while 
also allowing a spacing tolerance for the pedestrian test mannequin 
position.
    NHTSA is proposing different test scenarios in which the pedestrian 
test mannequin enters the path of the subject vehicle, including 
entering from the right side and left side of the subject vehicle's 
lane. For a pedestrian test mannequin initially positioned on the right 
side, NHTSA proposes an origination point that is 4.0 0.1 m 
(13.1 0.3 ft) from the subject vehicle's intended travel 
path. For a pedestrian test mannequin initially positioned on the left 
side, NHTSA proposes an origination point that is 6.0 0.1 m 
(19.7 0.3 ft) from the intended travel path. These initial 
pedestrian test mannequin positions are somewhat longer than those 
specified in NHTSA's 2019 draft test procedures for PAEB, which specify 
a right-side test mannequin offset of 3.5 m (11.5 ft) and left-side 
test mannequin offset of 5.5 m (18.0 ft).\212\ NHTSA is proposing the 
larger test mannequin offsets because the agency has found that the 
test mannequin sways and oscillates in an inconsistent manner when it 
is just starting to move, and the extra distance will provide time for 
it to stabilize before entering the subject vehicle's travel path. 
This, in turn, will enhance repeatability and accuracy of the test.
---------------------------------------------------------------------------

    \212\ 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.
---------------------------------------------------------------------------

    For test scenarios with a moving pedestrian test mannequin, NHTSA 
proposes to specify the maximum distance for the pedestrian test 
mannequin to reach its intended speed. NHTSA is proposing 1.5 m (4.9 
ft) as the maximum distance which will be used for both crossing path 
test scenarios and along path test scenarios. Although it is generally 
desirable for the test mannequin to attain its final speed as quickly 
as possible to efficiently execute tests, the agency has found that 
acceleration that is too sudden often results in inconsistent, jerky 
test mannequin motions that may compromise repeatability. NHTSA 
therefore is proposing distances that are similar to the requirements 
in NHTSA's 2019 draft research test procedures for a PAEB system.
    NHTSA is proposing that the simulated walking speed of the 
pedestrian test mannequin be maintained within 0.4 km/h (0.2 mph)

[[Page 38701]]

during PAEB tests. In NHTSA's 2020 PAEB research experience in 
conducting hundreds of tests, this amount of test mannequin speed 
tolerance is consistently achievable and provides a high level of run-
to-run repeatability and consistent test results.
    NHTSA is proposing clear test completion criteria to establish a 
point when a PAEB test may be considered fully concluded. In all PAEB 
test scenarios, a test is immediately complete if the subject vehicle 
makes contact with the pedestrian test mannequin. In test scenarios 
with the pedestrian test mannequin either crossing or stationary within 
the subject vehicle path, a test is complete when the subject vehicle 
comes to a complete stop without contacting the pedestrian test 
mannequin. In scenarios where the pedestrian mannequin moves along the 
forward path of the subject vehicle, the test is complete when the 
subject vehicle slows to below the pedestrian test mannequin speed. 
These test completion criteria are important for identifying a pass-
fail outcome for PAEB-equipped light vehicles. These criteria also are 
needed to limit consideration of vehicle motion or behavior after there 
is no longer a risk of collision with a pedestrian test mannequin.
    NHTSA is proposing that, when conducting PAEB tests with two VTDs, 
their left sides are aligned on the same plane, and they are positioned 
1.0 0.1 m (3.3 0.3 ft) from the subject 
vehicle's right side when coincident with the intended travel path. The 
VTD positioning is consistent with NHTSA's 2019 draft research test 
procedures for PAEB systems for the scenario where an obscured child 
test mannequin runs into traffic from behind two parked vehicles. These 
test specifications are repeatable and provide for consistent test 
results.

H. False Positive AEB Test Procedures

    For the steel trench plate test, the starting point, L0, 
is measured between the subject vehicle's front plane and the leading 
edge (closest to the subject vehicle) of the steel trench plate. For 
the pass-through scenario, the starting point is measured between the 
front plane of the subject vehicle and the vertical plane that contains 
the rearmost point of the vehicle test devices.
    NHTSA is proposing criteria to clearly establish when a false-
activation test trial may be considered fully concluded. For steel 
trench plate tests, a test trial is complete when the subject vehicle 
either comes to a stop or passes the leading edge of the steel trench 
plate. For the pass-through test, a test trial is complete when the 
subject vehicle either comes to a stop or passes between the vehicle 
test devices. These criteria provide a definitive, observable pass-fail 
basis for false-activation test outcomes in each of the two scenarios.

I. Environmental Test Conditions

    NHTSA proposes testing AEB systems in daylight and in darkness to 
ensure performance in a wide range of ambient light conditions.
    For daylight testing, the proposed ambient illumination at the test 
site is not less than 2,000 lux.\213\ This minimum level approximates a 
typical roadway light level on an overcast day.\214\ The acceptable 
range also includes any higher illumination level including levels 
associated with bright sunlight on a clear day.
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    \213\ This illumination threshold is the same as that adopted in 
SAE J3087 ``Automatic Emergency Braking (AEB) System Performance 
Testing.''
    \214\ During an overcast day (no sun), when the solar altitude 
is around 6 degrees, the light intensity on a horizontal surface is 
around 2,000 lux. Illuminating Engineering Society of North America. 
1979. ``Recommended Practice of Daylighting.''
---------------------------------------------------------------------------

    To ensure test repeatability, the agency further proposes that 
testing is not performed while the intended travel path is such that 
the heading angle of the vehicle is less than 25 degrees with respect 
to the sun \215\ and while the solar elevation angle is less than 15 
degrees. The intensity of low-angle sunlight aligned directly into the 
sensing element of a camera or other optical AEB sensor can saturate or 
``wash out'' the sensor and lead to unrepeatable test results. Also, 
low-angle sunlight may create long shadows around a test vehicle, which 
could potentially compromise test repeatability.
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    \215\ The horizontal angle between the sun and a vertical plane 
containing the centerline of the subject vehicle would be not less 
than 25 degrees for a valid test.
---------------------------------------------------------------------------

    For the proposed PAEB testing in darkness, the ambient illumination 
at the test site must be no greater than 0.2 lux. This value 
approximates roadway lighting in dark conditions without direct 
overhead lighting with moonlight and low levels of indirect light from 
other sources, such as reflected light from buildings and signage. An 
illumination level of 0.2 lux also is the same level specified in the 
test procedures for the recently issued final rule for adaptive driving 
beams.\216\ This darkness level accounts for the effect ambient light 
has on AEB performance, particularly for camera-based systems. This 
ensures robust performance of all AEB systems, regardless of what types 
of sensors they may use.
---------------------------------------------------------------------------

    \216\ 87 FR 9916.
---------------------------------------------------------------------------

    NHTSA proposes that the ambient temperature in the test area be 
between 0 Celsius (32 [deg]F) and 40 Celsius (104 [deg]F) during AEB 
testing. This ambient temperature range matches the range specified in 
NHTSA's safety standard for brake system performance.\217\ These 
temperatures represent a wide range of conditions that AEB-equipped 
vehicles will encounter. While AEB controls and sensors can operate at 
lower temperatures, the limiting factor in this case is the braking 
performance. The reduced surface friction possible in below-freezing 
temperatures may result in unrepeatable test conditions and may 
adversely affect subject vehicle braking performance.
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    \217\ FMVSS No. 135--Light vehicle brake systems.
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    NHTSA is proposing that the maximum wind speed during AEB 
compliance testing be no greater than 10 m/s (22 mph) for lead vehicle 
avoidance tests and 6.7 m/s (15 mph) for pedestrian avoidance tests. 
These are the same maximum wind speeds specified for AEB tests in the 
agency's AEB NCAP procedures and PAEB draft research test 
procedure.218 219 Excessive wind during testing could 
disturb the test devices in various ways. For example, high wind speeds 
could affect the ability of the VTD to maintain consistent speed and/or 
lateral position. The pedestrian mannequin could bend or sway 
unpredictably in excessively windy conditions. Test equipment that 
needs to remain stable also could be affected by wind. To ensure test 
repeatability, the agency has tentatively decided to adopt these wind 
speed specifications to minimize wind effects during testing.
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    \218\ National Highway Traffic Safety Administration (2014, 
August), Crash imminent brake system performance evaluation (working 
draft). Available at: https://www.regulations.gov/document/NHTSA-2012-0057-0038.
    \219\ 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.
---------------------------------------------------------------------------

    NHTSA is proposing that AEB compliance tests not be conducted 
during periods of precipitation, including rain, snow, sleet, or hail. 
The presence of precipitation could influence the outcome of the tests. 
Wet, icy, or snow-covered pavement has lower friction, which may affect 
the outcome of the test. More importantly, in those conditions compared 
to dry conditions, it is more difficult to reproduce a friction level 
with good precision. Therefore, the agency is proposing to adopt the 
precipitation specification specified in the agency's NCAP test 
procedures for AEB systems.
    NHTSA is proposing that AEB performance tests be conducted when 
visibility at the test site is unaffected by

[[Page 38702]]

fog, smoke, ash, or airborne particulate matter. AEB systems may use 
cameras to detect other vehicles and pedestrians. Reduced visibility 
due to the presence of fog or other substances is difficult to 
reproduce in a manner that produces repeatable test results. A current 
industry standard specifies that the horizontal visibility at ground 
level must be greater than 1 km (0.62 miles), and AEB test procedures 
in the European NCAP use that requirement.220 221 NHTSA 
believes a minimum visibility range is unnecessary to ensure test 
repeatability. Therefore, the agency is proposing a limitation on the 
presence of conditions that would obstruct visibility, including fog or 
smoke during AEB testing, but is not proposing a minimum visibility 
range. NHTSA seeks comment on whether to adopt a minimum level of 
visibility.
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    \220\ SAE International (2017), Automatic Emergency Braking 
(AEB) System Performance Testing (SAE J3087).
    \221\ European New Car Assessment Program (Euro NCAP) (2019, 
July), Test Protocol--AEB Car-to-Car systems, Version 3.0.2.
---------------------------------------------------------------------------

J. Test Track Conditions

    NHTSA is proposing that the test track surface have a peak friction 
coefficient of 1.02 when measured using an ASTM F2493 standard 
reference test tire, in accordance with ASTM E1337-19 at a speed of 
64.4 km/h (40 mph), without water delivery.\222\ Surface friction is a 
critical factor in brake system performance testing, including AEB. The 
presence of moisture will significantly change the measured performance 
of a braking system. A dry surface is more consistent and provides for 
greater test repeatability. The proposed peak friction coefficient is 
the same value that NHTSA selected for an update of a NHTSA FMVSS 
related to surface friction for brake performance testing.\223\
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    \222\ ASTM E1337-19, Standard Test Method for Determining 
Longitudinal Peak Braking Coefficient (PBC) of Paved Surfaces Using 
Standard Reference Test Tire.
    \223\ 87 FR 34800 (June 8, 2022), Final rule, Standard Reference 
Test Tire.
---------------------------------------------------------------------------

    NHTSA is proposing that the test surface have a consistent slope 
between 0 and 1 percent. The slope of a road surface can affect the 
performance of an AEB-equipped vehicle.\224\ It also influences the 
dynamics and layout involved in the proposed AEB test scenarios for 
both lead vehicle AEB and PAEB. Therefore, NHTSA proposes to limit the 
slope of the test surface by adopting the slope requirement specified 
for AEB tests in the agency's lead vehicle AEB NCAP procedures and PAEB 
draft research test procedure.225 226
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    \224\ Kim, H. et al., Autonomous Emergency Braking Considering 
Road Slope and Friction Coefficient, International Journal of 
Automotive Technology, 19, 1013-1022 (2018).
    \225\ National Highway Traffic Safety Administration (2014, 
August), Crash imminent brake system performance evaluation (working 
draft). Available at: https://www.regulations.gov/document/NHTSA-2012-0057-0038.
    \226\ 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.
---------------------------------------------------------------------------

    NHTSA proposes that the lead vehicle and pedestrian test mannequin 
be unobstructed from the subject vehicle's view during compliance tests 
except where specified. Furthermore, each compliance test would be 
conducted without any vehicles, obstructions, or stationary objects 
within one lane width of either side of the subject vehicle's path 
unless specified as part of the test procedure. This test condition is 
the same as that specified in the agency's research test procedures for 
AEB systems. The presence of unnecessary objects near the path of the 
subject vehicle could interfere with detection of a lead vehicle or 
test mannequin and have an unintentional effect on the field of view of 
the AEB system, which may compromise test repeatability.

K. Subject Vehicle Conditions

    NHTSA is proposing that the subject vehicle be loaded with not more 
than 277 kg (611 lb.), which includes the sum of any vehicle occupants 
and any test equipment and instrumentation. The agency proposes this 
lightly loaded vehicle specification because the primary goal of the 
AEB testing is to measure the sensing and perception capability of a 
vehicle, which is relatively insensitive to the level of the vehicle 
load. In addition, braking tests with fully loaded vehicles are already 
required and conducted under exiting FMVSS, such as FMVSS No. 135, 
Light Vehicle Brake Systems, to measure the maximum brake capacity of a 
vehicle.
    To maximize test repeatability, NHTSA is proposing that subject 
vehicle brakes be burnished prior to AEB performance testing according 
to the specifications of either S7.1 of FMVSS No. 135, which applies to 
passenger vehicles with GVWR of 3,500 kilograms or less, or according 
to the specifications of S7.4 of FMVSS No. 105, which applies to 
passenger vehicles with GVWR greater than 3,500 kilograms. AEB 
capability relies upon the function of the service brakes on a vehicle. 
Thus, it is reasonable and logical that the same pre-test conditioning 
procedures that apply to service brake performance evaluations should 
also apply to AEB system performance evaluations.
    To maximize test repeatability, NHTSA is proposing that the subject 
vehicle service brakes be maintained at an average temperature between 
65 [deg]C (149 [deg]F) and 100 [deg]C (212 [deg]F). The brake 
temperature is evaluated using either the front or rear brakes, 
depending on which has a higher temperature. This temperature range is 
the same as the range specified in NHTSA's safety standard for light 
vehicle brake systems \227\ and is important for consistent brake 
performance and test repeatability. Foundation brakes that are too cool 
or too hot may perform with less consistency, such that stopping 
distance may be unrepeatable. Hot or cold brakes also may fade or 
experience stiction or other effects that exacerbate inconsistent brake 
performance.
---------------------------------------------------------------------------

    \227\ FMVSS No. 135--Light vehicle brake systems.
---------------------------------------------------------------------------

    User adjustable settings, such as regenerative braking settings and 
FCW settings, would be tested in any setting state. Furthermore, 
adaptive and traditional cruise control may be used in any selectable 
setting during testing. The agency would test vehicles with any cruise 
control or adaptive cruise control setting to make sure that these 
systems do not disrupt the ability for the AEB system to stop the 
vehicle in crash imminent situations. However, for vehicles that have 
an ESC off switch, NHTSA will keep ESC engaged for the duration of the 
test.

VIII. Test Devices

A. Pedestrian Test Mannequins

    NHTSA is proposing specifications for two pedestrian test devices 
to be used for compliance testing for the new PAEB requirements. These 
specifications would be referenced within the PAEB test procedures and 
NHTSA would use test devices meeting these specifications when it 
performs compliance testing. The two pedestrian test devices would each 
consist of a test mannequin and a motion apparatus (carrier system) 
that positions the test mannequin during a test. NHTSA is proposing 
specifications for a pedestrian test mannequin representing a 50th 
percentile adult male and a pedestrian test mannequin representing a 6- 
to 7-year-old child. NHTSA would use these pedestrian test mannequins 
to ensure that light vehicles are equipped with PAEB systems that 
detect pedestrians and automatically provide emergency braking to avoid 
pedestrian test mannequin contact in the tests specified in this 
proposal. NHTSA is proposing to

[[Page 38703]]

incorporate by reference specifications from three ISO standards.
1. Background
    Since the introduction of PAEB, vehicle manufacturers and other 
entities have been engaged in testing and evaluating the technology. 
Because testing cannot be performed with live pedestrians, test 
mannequins have been developed to facilitate a safe and practical way 
to perform these evaluations objectively. However, to ensure the PAEB 
systems operate as intended, the test mannequins must be representative 
of pedestrians from the perspective of the vehicle sensors. That is, 
sensors used to detect the test mannequins must operate as if they were 
detecting actual pedestrians in the real world, which in turn allows 
the PAEB system to interpret and respond to the sensor data in a 
realistic manner. This representativeness ensures that PAEB system test 
results translate to real-world safety benefits.
    There have been several efforts by different organizations to 
develop common specifications for PAEB testing, including an ISO 
Standard, ISO 19206-2:2018, ``Road vehicles--Test devices for target 
vehicles, vulnerable road users and other objects, for assessment of 
active safety functions--Part 2: Requirements for pedestrian targets,'' 
and an SAE Recommended Practice, SAE International Standard J3116, 
``Active Safety Pedestrian Test Mannequin Recommendation.'' ISO 19206-
4:2020, ``Road vehicles--test devices for target vehicles, vulnerable 
road users and other objects, for assessment of active safety 
functions--Part 4: Requirements for bicyclists targets,'' has color and 
infrared reflectivity specifications. Additionally, Euro NCAP specifies 
use of test mannequins that conform to the specifications in its 
``Articulated Pedestrian Target Specification Document,'' \228\ which 
sets specifications for size, color, motion patterns, and detectability 
by vehicle sensors.
---------------------------------------------------------------------------

    \228\ European Automobile Manufacturers' Association (ACEA), 
February 2016, ``Articulated Pedestrian Target Specification 
Document,'' Version 1.0, available at https://www.acea.auto/publication/articulated-pedestrian-target-acea-specifications/.
---------------------------------------------------------------------------

    In November 2019, NHTSA published a Federal Register notice that 
sought comment on NHTSA's draft research test procedure for PAEB 
testing (84 FR 64405). The draft test procedures provided methods and 
specifications for performing PAEB systems performance 
evaluations.\229\ During the development of these test procedures, 
NHTSA used the 4activePS pedestrian static mannequin that was developed 
by 4Active Systems.\230\ The 4activePS pedestrian static mannequin was 
developed specifically for testing PAEB systems and conforms to the 
specifications in ISO 19206-2:2018. NHTSA continues to test with test 
mannequins developed by 4Active Systems. However, NHTSA has 
transitioned to performing tests using the 4activePA, which has 
articulated legs.
---------------------------------------------------------------------------

    \229\ 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.
    \230\ Id. at 8, citing 4activeSystems GmbH. (n.a.). 4activePS 
pedestrian static (web page). Traboch, Austria: Author. Available at 
www.4activesystems.at/en/products/dummies/4activeps.html.
---------------------------------------------------------------------------

    The change from using static mannequins to mannequins equipped with 
articulated, moving legs is in response to information that 
demonstrates that articulated mannequins may be more representative of 
actual pedestrians. In response to NHTSA's 2015 NCAP request for 
comments notice, the agency received comments asking that NHTSA use 
articulated mannequins to test PAEB systems. The commenters reasoned 
that the articulated mannequins better represent actual pedestrians. In 
response to these comments, NHTSA proposed, in its 2022 NCAP RFC, the 
use of articulated mannequins.\231\ In adopting this approach, NHTSA 
noted that using articulating mannequins would harmonize with other 
major consumer information-focused entities that use articulating 
mannequins, such as Euro NCAP and IIHS.\232\
---------------------------------------------------------------------------

    \231\ 87 FR 13452, March 9, 2022, supra.
    \232\ Id.
---------------------------------------------------------------------------

    For the test scenarios involving a moving pedestrian, NHTSA is 
proposing that the legs of the pedestrian test mannequin would 
articulate to emulate a walking motion.\233\ A test mannequin that has 
leg articulation when in motion more realistically represents an actual 
walking or running pedestrian. For test scenarios involving a 
stationary pedestrian, NHTSA is proposing that the legs of the 
pedestrian test mannequin remain at rest (i.e., emulate a standing 
posture).
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    \233\ The velocity of the articulated legs could be detected by 
an AEB system because some sensing technologies, such as radar, 
``may be able to measure and detect the relative velocities of 
moving legs.'' Since the articulated legs of the current test 
mannequin move at a constant pace during a test, identifying proper 
leg velocities for a range of speeds would be needed in developing 
the next generation test mannequin. European Automobile 
Manufacturers' Association (ACEA), February 2016, ``Articulated 
Pedestrian Target Specification Document,'' Version 1.0. https://www.acea.auto/publication/articulated-pedestrian-target-acea-specifications/.
---------------------------------------------------------------------------

    In developing the specifications for the pedestrian test mannequins 
that will be used in NHTSA compliance testing, NHTSA first considered 
what characteristics these devices need to have. Not only does a test 
mannequin need to be able to facilitate accurate, repeatable, and 
reproducible tests when used for compliance testing, but it must also 
ensure that performance during the PAEB tests will be representative of 
performance in the real world. This means that a PAEB system should 
detect and classify the test mannequin similarly to real pedestrians.
    It is NHTSA's understanding that PAEB systems currently on the 
market may use a combination of camera and radar-based systems, and 
that Automated Driving Systems may also use lidar systems. NHTSA is 
proposing specifications for the pedestrian test mannequin based on 
these technologies. These specifications include those for visual 
characteristics, such as the color and physical dimensions. They also 
include specifications for infrared reflectivity, radar cross section, 
and articulation (the latter two affect how radar-based systems will 
perceive the pedestrian test mannequin radar signature).
    Additionally, NHTSA has considered the need for the test mannequins 
to allow for safe and non-destructive testing. In the course of testing 
PAEB systems, the subject vehicle may impact the test mannequin. In the 
event contact is made, it is important that the test mannequin has 
characteristics that do not pose safety risks to those conducting the 
tests. From a practical standpoint, it is also important for test 
mannequins to be durable so they can be used repeatedly, yet strikable 
in a way that minimizes the risk of damage to the subject vehicle 
should contact be made with the test mannequin, even at a high relative 
velocity.
    NHTSA's proposed specifications incorporate by reference existing 
industry standards that represent the culmination of many years of 
coordination and research. NHTSA not only believes these specifications 
are sufficient to ensure that test results are objective and translate 
to real-world safety benefits, but also that there are currently 
available test mannequins that meet these specifications and possess 
characteristics that allow for safe and non-destructive testing.
2. Mannequin Appearance
    The pedestrian test mannequin specification includes basic body 
proportions that, from any angle,

[[Page 38704]]

represent either a 50th percentile adult male or a 6 to 7-year-old 
child. The pedestrian test mannequins' specifications include a head, 
torso, two arms, and two articulating legs. The pedestrian test 
mannequin appears clothed in a black long-sleeved shirt and blue long 
pants. The black shirt and blue pants are selected to challenge a 
camera system, as the minimal contrast between the shirt and pants is 
challenging for a camera system to detect.
    The physical dimensions of the pedestrian test mannequins are 
intended to be consistent with live pedestrians. NHTSA is proposing 
that the pedestrian test mannequins have the dimensions specified in 
ISO 19206-2:2018, which would be incorporated by reference into 
proposed 49 CFR part 561.
    Evaluation of crash data indicates that the pedestrian injury and 
fatality safety problem is one that predominately affects adults, with 
adults aged 21 or older comprising 93 percent of all pedestrian 
fatalities.\234\ However, to address child pedestrian safety, NHTSA is 
proposing requirements for a scenario representing a child running into 
the street from an obstructed location, such as from behind a parked 
car. Children are among the most vulnerable road users, especially in 
the absence of adult supervision. Due to the small size of children, 
they can be obstructed from view until they are already in the travel 
path of a vehicle. This situation can be challenging for drivers and 
represents an area in which PAEB can also offer safety benefits.
---------------------------------------------------------------------------

    \234\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813079 Pedestrian Traffic Facts 2019 Data, May 2021.
---------------------------------------------------------------------------

    Both the ISO Standard and SAE Recommended Practice J3116 set forth 
specifications for an adult and child test mannequin. The ISO Standard 
specifies a 50th percentile adult male test mannequin and a 6 to 7-
year-old child test mannequin. The SAE recommendation specifies an 
adult test mannequin based on the average adult pedestrian involved in 
fatal pedestrian crashes, and a 6-year-old child test mannequin. The 
specific dimensions for the test mannequins differ slightly between the 
two recommended practices, but NHTSA has tentatively concluded that 
this difference is immaterial as it relates to this NPRM. As an 
example, one of the biggest differences in dimensions is the height of 
the adult test mannequin, where the ISO document specifies a height for 
the adult test mannequin of 1800 mm (70.9 in) with shoes and the SAE 
specifies a height of 1715 mm (67.5 in) without shoes (the SAE 
recommended practice provides no recommendation for shoe height, or for 
a test mannequin with shoes).\235\ In considering the appropriate 
dimensions for the test mannequins used for AEB testing, NHTSA found 
most persuasive ISO 19206-2:2018, particularly due to the wide adoption 
of the specification and commercial availability of test mannequins 
based on the specification.\236\ Furthermore, NHTSA uses the test 
mannequins recommended in the ISO standard for all PAEB tests. NHTSA 
has no information on how a different recommendation for the test 
mannequin, such as the SAE recommended practice, would affect 
correlation between results and test repeatability. However, NHTSA 
requests comments on whether it would be more appropriate to use the 
SAE Recommended Practice specifications because they are more 
representative of the average pedestrian fatality.
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    \235\ A mannequin wearing shoes is representative of a person 
crossing the road. If considering a 30 mm (1.2 in) height for shoes 
the differences in height between the two recommended practices is 
55 mm (2.2 in).
    \236\ NHTSA is not aware of any commercially available test 
mannequins conforming to SAE J3116.
---------------------------------------------------------------------------

    For the remaining proposed PAEB scenarios, NHTSA is proposing to 
use only the adult test mannequin. For these scenarios, NHTSA is 
proposing specifications that are largely from ISO 19206-2:2018. 
However, for color and infrared reflectivity, including skin color, 
NHTSA is proposing specifications from ISO 19206-4:2020, ``Road 
vehicles--test devices for target vehicles, vulnerable road users and 
other objects, for assessment of active safety functions--Part 4: 
Requirements for bicyclists targets.''
    NHTSA believes that it is important for PAEB performance 
requirements to ensure real world safety benefits across a broad 
spectrum of real-world pedestrian crash scenarios. While NHTSA 
understands that, for practical reasons the performance requirements 
cannot address every pedestrian crash scenario, NHTSA also seeks to 
understand better whether the specifications for the adult test 
mannequin in the ISO standards are reasonably sufficient to address the 
crash risks for pedestrians of other sizes, such as small adult women. 
NHTSA seeks comment on whether use of the 50th percentile adult male 
test mannequin ensures PAEB systems would react to small adult females 
and other pedestrians other than mid-size adult males.
    NHTSA has considered whether a small adult female mannequin is 
necessary. However, NHTSA is unaware of any standards providing 
specifications for a 5th percentile adult female test mannequin, or of 
any consumer information programs testing with such a device. Instead, 
NHTSA seeks comment on whether the child test mannequin also should be 
specified for use in all PAEB scenarios. Such an approach could better 
ensure that PAEB systems are able to perceive and respond to a larger 
range of pedestrians in the real world than if only the 50th percentile 
adult male test mannequin was prescribed. However, as NHTSA has not 
performed testing with the child test mannequin in all of the test 
scenarios, the agency requests comment on whether such a requirement is 
feasible or appropriate.
    In summary, NHTSA is proposing to incorporate by reference the 
dimensions and posture specifications found in ISO 19206-2:2018 for a 
test mannequin representing a 50th percentile adult male and a 6- to 7-
year-old child. NHTSA considers these specifications to be an 
appropriate representation for the test mannequins. Specifically, NHTSA 
is proposing to incorporate by reference the complete set of dimensions 
for the adult and child test mannequins found in Annex A, Table A.1 of 
ISO 19206-2:2018. NHTSA is also proposing to incorporate by reference 
Figures A.1 and A.2, which illustrate reference dimensions for the 
adult and child test mannequins.
3. Color and Reflectivity
    Specifications for test mannequin skin color are not found in ISO 
19206-2:2018. Further, while the standard provides specifications for 
reflectivity, it does not include procedures for measuring it. For 
these reasons, NHTSA is proposing to incorporate by reference the 
bicyclist mannequin specifications for color and reflectivity found in 
ISO 19206-4:2018, ``Road vehicles--test devices for target vehicles, 
vulnerable road users and other objects, for assessment of active 
safety functions--Part 4: Requirements for bicyclists targets.'' 
Although this standard provides requirements for bicyclist test 
devices, NHTSA proposes to reference these specifications for color and 
reflectivity for the prescribed adult and child test mannequins because 
the specifications appear workable for use with the ISO Standard for 
pedestrian test devices. NHTSA is specifying that the test mannequins 
be of a color that matches a specified range of skin colors 
representative of very dark to very light complexions, with features 
that

[[Page 38705]]

represent hair, facial skin, hands, a long-sleeve black shirt, blue 
long pants, and black shoes.
    NHTSA believes that the specifications in ISO 19206-4:2020 for 
color and infrared reflectivity for a bicyclist mannequin can be used 
for PAEB testing and should be incorporated by reference to fill in 
gaps in ISO 19206-2:2018 for those specifications. Not only would these 
specifications provide needed specifications for these features, but 
they also allow NHTSA to harmonize with specifications for test 
mannequins in use by Euro NCAP.
4. Radar Cross Section
    Some PAEB systems use radar sensors to detect the presence of 
pedestrians. Accordingly, NHTSA is proposing that the pedestrian test 
mannequins have radar reflectivity characteristics that are 
representative of real pedestrians. Specifically, NHTSA is proposing 
that the radar cross section of the pedestrian test mannequin, when 
measured in accordance with procedures specified in ISO 19206-2:2018, 
Annex C, fall within the upper and lower boundaries shown in Annex B, 
Section B.3, Figure B.6.
5. Other Considerations
    In addition to the characteristics specified in this proposal, 
NHTSA considered whether the test mannequins should have thermal 
characteristics. NHTSA believes there is a potential that thermal 
sensing technologies may be used in active safety systems in the 
future. While NHTSA does not want to dissuade manufacturers from 
developing or implementing such technology, the agency is not aware of 
any vehicle manufacturers currently using such technology for the 
detection of pedestrians as part of a PAEB system. NHTSA has also not 
conducted research on what specifications would be needed to ensure 
that a test mannequin has thermal characteristics that are 
representative of real-world pedestrians. Accordingly, NHTSA has not 
included thermal specifications for the pedestrian test mannequins in 
the draft regulatory text.
    NHTSA also considered whether it was necessary to propose 
specifications for the motion of the pedestrian test mannequin carrier 
system. The carrier system is needed to control the speed (where 
applicable) and position of the pedestrian test device. Specifically, 
this equipment is needed to achieve the necessary closed-loop test 
scenario choreography between the subject vehicle and pedestrian test 
mannequin (e.g., lateral overlap relative to the front of the subject 
vehicle and desired baseline contact points). ISO 19206-2:2018 provides 
recommended specifications in section 7. These specifications are 
designed to ensure that the carrier system is capable of positioning 
the pedestrian test mannequin relative to the target within the 
specific tolerances required by the different test procedures. Careful 
positioning is necessary because the relative position and speed of the 
subject vehicle and pedestrian test mannequin need to be consistent in 
order to achieve repeatable and reproducible test results.
    However, ISO 19206-2:2018 also includes specifications intended to 
ensure that the carrier system minimally affects how the pedestrian 
test mannequin is perceived by the subject vehicle. Tentatively, NHTSA 
has concluded that including specifications for the pedestrian test 
mannequin carrier system itself is not necessary. This is primarily 
because no specific reflective or radar characteristics of the carrier 
system are needed to ensure objective and representative PAEB testing. 
Moreover, the characteristics of the carrier system should be 
irrelevant for conducting the test, as the carrier system ought not 
bear on the results of the test. To the extent that the carrier system 
is detected by a PAEB-equipped vehicle during compliance testing, NHTSA 
believes that such detection would not adversely affect the test 
result. Accordingly, NHTSA intends to use a carrier system for 
compliance testing that has minimal radar cross-section and minimal 
optical features based on test environment.

B. Vehicle Test Device

1. Description and Development
    To ensure repeatable and reproducible testing that reflects how a 
subject vehicle would be expected to respond to an actual vehicle in 
the real world, this proposal includes broad specifications for a 
vehicle test device to be used as a lead vehicle, pass through vehicle, 
or obstructing vehicle during testing. NHTSA is proposing that the 
vehicle test device be based on certain specifications defined in ISO 
19206-3:2021, ``Road vehicles--Test devices for target vehicles, 
vulnerable road users and other objects, for assessment of active 
safety functions--Part 3: Requirements for passenger vehicle 3D 
targets.'' \237\ The vehicle test device is a tool that NHTSA proposes 
to use to facilitate the agency's compliance tests to measure the 
performance of AEB systems required by the proposed FMVSS. This NPRM 
describes the vehicle test device that NHTSA would use.
---------------------------------------------------------------------------

    \237\ https://www.iso.org/standard/70133.html. May 2021.
---------------------------------------------------------------------------

    The surrogate vehicle NHTSA currently uses in its research testing 
is the Global Vehicle Target (GVT). The GVT is a full-sized harmonized 
surrogate vehicle developed to test crash avoidance systems while 
addressing the limitations of earlier generation surrogate vehicles. To 
obtain input from the public and from industry stakeholders, NHTSA 
participated in a series of five public workshops and three radar 
tuning meetings between August 2015 and December 2016. These workshops 
and meetings provided representatives from the automotive industry with 
an opportunity to inspect, measure, and assess the realism of prototype 
surrogates during the various stages of development. Workshop and 
meeting participants were permitted to take measurements and collect 
data with their own test equipment, which they could then use to 
provide specific recommendations about how the surrogate vehicle's 
appearance, to any sensor, could be improved to increase realism.
    After feedback from automotive vehicle manufacturers and suppliers 
was incorporated into an earlier design of the GVT, a series of high-
resolution radar scans were performed by the Michigan Tech Research 
Institute (MTRI) under NHTSA contract. These measurements provided an 
independent assessment of how the radar characteristics of the GVT 
compared to those from four real passenger cars.\238\ This study found 
that the GVT has generally less radar scatter than the real vehicles to 
which it was compared. However, MTRI found that ``even though the [GVT] 
may more often reflect a greater amount of energy than the [real] 
vehicles, it is not exceeding the maximum energy of the returns from 
the vehicles. Thus, a sensor intended for the purpose of detecting 
vehicles should perform well with the [GVT].'' \239\
---------------------------------------------------------------------------

    \238\ The comparison passenger cars used were a 2008 Hyundai 
Accent, a 2004 Toyota Camry, a 2016 Ford Fiesta hatchback, and a 
2013 Subaru Impreza.
    \239\ Buller, W., Hart, B., Aden, S., and Wilson, B. (2017, May) 
``Comparison of RADAR Returns from Vehicles and Guided Soft Target 
(GST),'' Michigan Technological University, Michigan Tech Research 
Institute. Docket NHTSA-2015-0002-0007 (www.regulations.gov).
---------------------------------------------------------------------------

    NHTSA also performed tests to determine the practicality of using 
the GVT for test-track performance evaluations by examining how 
difficult it was to reassemble the GVT after it was struck in a test. 
Using a randomized matrix designed to minimize the effect

[[Page 38706]]

of learning, these tests were performed with teams of three or five 
members familiar with the GVT reassembly process.\240\ NHTSA found that 
reassembly of the GVT on the robotic platform takes approximately 10 
minutes to complete; however, additional time is often required to re-
initialize the robotic platform GPS afterwards.\241\
---------------------------------------------------------------------------

    \240\ Snyder, Andrew C. et al., ``A Test Track Comparison of the 
Global Vehicle Target (GVT) and NHTSA's Strikeable Surrogate Vehicle 
(SSV),'' July 2019 https://rosap.ntl.bts.gov/view/dot/41936.
    \241\ Id.
---------------------------------------------------------------------------

    Finally, NHTSA conducted its own crash imminent braking tests to 
compare the speed reduction achieved by three passenger cars as they 
approached the GVT, compared to the Strikable Surrogate Vehicle (SSV), 
the surrogate vehicle NHTSA currently uses for its NCAP AEB tests. 
These tests found that any difference that might exist between the GVT 
and the SSV were small enough to not appreciably influence the outcome 
of vehicle testing.\242\
---------------------------------------------------------------------------

    \242\ Id.
---------------------------------------------------------------------------

    When used during lead vehicle AEB testing, the GVT is secured to 
the top of a low-profile robotic platform. The robotic platform is 
essentially flat and is movable and programmable. The vehicle test 
device's movement can be accurately and repeatably defined and 
choreographed with the subject vehicle and testing lane through the use 
of data from the robotic platform's on-board inertial measurement unit, 
GPS, and closed-loop control facilitated by communication with the 
subject vehicle's instrumentation. The shallow design of the robotic 
platform allows the tested vehicle to drive over it. The GVT is secured 
to the top of the robotic platform using hook-and-loop fastener 
attachment points, which allow the pieces of the GVT to easily and 
safely break away without significant harm to the vehicle being tested 
if struck.
    The internal frame of the GVT is constructed primarily of vinyl-
covered foam segments held together with hook-and-loop fasteners. The 
GVT's exterior is comprised of multiple vinyl ``skin'' sections 
designed to provide the dimensional, optical, and radar characteristics 
of a real vehicle that can be recognized as such by camera and radar 
sensors.\243\ If the subject vehicle impacts the GVT at low speed, the 
GVT is typically pushed off and away from the robotic platform without 
breaking apart. At higher impact speeds, the GVT breaks apart as the 
subject vehicle essentially drives through it.
---------------------------------------------------------------------------

    \243\ Id.
---------------------------------------------------------------------------

2. Specifications
    The most recent widely accepted iteration of vehicle test device 
specifications is contained in ISO 19206-3:2021. Using data collected 
by measuring the fixed-angle/variable-range radar cross section for 
several real vehicles, ISO developed generic ``acceptability 
corridors,'' which are essentially boundaries that the vehicle test 
device's radar cross section must fit within to be deemed 
representative of a real vehicle.\244\ All vehicles that ISO tested 
have radar cross section measurements that fit within the boundaries 
set forth in the ISO standard.
---------------------------------------------------------------------------

    \244\ The vehicles tested to develop the ISO standard are: 2016 
BMW M235i, 2006 Acura RL, 2019 Tesla Model 3, 2017 Nissan Versa, 
2018 Toyota Corolla, and 2019 Ford Fiesta.
---------------------------------------------------------------------------

    This proposal would incorporate by reference ISO 19206-3:2021 into 
NHTSA's regulations and specify that the vehicle test device meets 
several specifications in ISO 19206-3:2021, in addition to other 
specifications identified by NHTSA. Because the GVT was considered 
during the development of ISO 19206-3:2021, the GVT would meet the 
standard's specifications. However, should the design of the GVT change 
or a new vehicle test device be developed, reference to the more 
general specifications of ISO 19206-3:2021 should ensure that NHTSA is 
able to test with such other vehicle test devices, and should also 
ensure that such vehicle test devices have properties needed by an AEB 
system to identify it as a motor vehicle.
    The vehicle test device's physical dimensions are proposed to be 
consistent with those of the subcompact and compact car vehicle class. 
The specific range of dimensions in this proposal for individual 
surfaces of the vehicle test device are incorporated from ISO 19206-
3:2021, Annex A, Table A.4. These include specifications for the test 
device's width and the placement of the license plate, lights, and 
reflectors relevant to the rear-end of the vehicle test device.
    The vehicle test device is proposed to have features printed on its 
surface to represent features that are identifiable on the rear of a 
typical passenger vehicle, such as tail lamps, reflex reflectors, 
windows, and the rear license plate. The proposed color ranges for the 
various surface features, including tires, windows, and reflex 
reflectors, are incorporated from ISO 19206-3:2021, Annex B, Tables B.2 
and B.3. Table B.2 specifies the colors of the tires, windows, and 
reflectors, which reflect the colors observed the in the real world. 
The color of the exterior of the vehicle is specified to be a range 
representing the color white, which provides a high color contrast to 
the other identifiable features. White is also a common color for motor 
vehicles.\245\ The proposed reflectivity ranges for the various 
features on the vehicle test device are incorporated from ISO 19206-
3:2021, Annex B, Table B.1. Table B.3 specifies the recommended 
minimum, mean, and maximum color range for the white body, specifically 
the outer cover.
---------------------------------------------------------------------------

    \245\ Globally, white was the most popular color for light 
vehicles in 2021. https://gmauthority.com/blog/2022/02/white-was-
the-most-popular-car-color-again-in-2021/
#:~:text=According%20to%20PPG%2C%2035%20percent,by%20silver%20at%2011
%20percent.
---------------------------------------------------------------------------

    Because many AEB systems rely on radar sensors in some capacity to 
identify the presence of other vehicles, the vehicle test device must 
have a radar cross section that would be recognized as a real vehicle 
by an AEB system. In particular, the vehicle test device must have a 
radar cross section consistent with a real vehicle when approached from 
the rear over a range of distances.
    NHTSA is proposing that the radar cross section of the vehicle test 
device fall within an ``acceptability corridor'' when measured using an 
automotive-grade radar sensor. This acceptability corridor would be 
defined by the upper and lower boundaries specified by ISO 19206-
3:2021, Annex C, Equations C.1 and C.2, using the radar cross section 
boundary parameters defined in ISO 19206-3:2021, Annex C, Table C.3 for 
a fixed viewing angle of 180 degrees. NHTSA is aware that, unlike some 
predecessor specification documents, such as Euro NCAP Technical 
Bulletin 025 from May 2018, the ISO standard does not specify that the 
radar cross section measurements be verified using a specific model of 
radar. Rather, the ISO standard specifies that the radar sensor used 
have certain specifications and operational characteristics. NHTSA's 
proposal similarly does not specify that the vehicle test device's 
initial radar cross section be measured with a specific model or brand 
of radar. NHTSA only proposes that the radar sensor used to validate 
the radar cross section operate within the 76-81 GHz bandwidth, have a 
horizontal field of view of at least 10 degrees, a vertical field of 
view of at least 5 degrees, and a range greater than 100 m (328 ft). 
Additionally, NHTSA's proposal does not specify that the VTD's radar 
cross section during in-the-field verifications be performed to 
objectively assess whether the radar cross section still falls within 
the acceptability corridor. NHTSA seeks comment about whether

[[Page 38707]]

use of the optional field verification procedure provided in ISO 19206-
3:2021, Annex E, section E.3 should be used.
    Because the test procedures proposed in this rule only involve 
rear-end approaches by the subject vehicle, NHTSA is at this time only 
proposing to establish specifications applicable for the rear-end of 
the vehicle test device. NHTSA seeks comment on whether the 
specifications for the vehicle test device should include sides of the 
vehicle, as well as the rear-end. If NHTSA were to include, in a final 
rule, specifications for sides of a vehicle test device, NHTSA 
anticipates that those specifications would also be incorporated from 
ISO 19206-3:2021.
3. Alternatives Considered
    One alternative test device that NHTSA considered for use in its 
lead vehicle AEB evaluations was the agency's self-developed Strikable 
Surrogate Vehicle device, which NHTSA currently uses in its NCAP 
testing of AEB performance. NHTSA adopted the use of the SSV as part of 
its 2015 NCAP upgrade, under which the agency began testing AEB 
performance.\246\ The SSV resembles the rear section of a 2011 Ford 
Fiesta hatchback. The SSV is constructed primarily from a rigid carbon 
fiber mesh, which allows it to maintain a consistent shape over time 
(unless damaged during testing). To maximize visual realism, the SSV 
shell is wrapped with a vinyl material that simulates paint on the body 
panels and rear bumper, and a tinted glass rear window. The SSV is also 
equipped with a simulated United States specification rear license 
plate. The taillights, rear bumper reflectors, and third brake light 
installed on the SSV are actual original equipment from a production 
vehicle. NHTSA testing shows that AEB systems will recognize the SSV 
and will respond in a way that is comparable to how they would to an 
actual vehicle.\247\
---------------------------------------------------------------------------

    \246\ 80 FR 68604.
    \247\ www.regulations.gov. NHTSA Docket Nos. NHTSA-2012-0057-
0032, NHTSA-2012-0057-0034, and NHTSA-2012-0057-0039.
---------------------------------------------------------------------------

    While the SSV and GVT are both recognized as real vehicles by AEB 
systems from the rear approach aspect, the SSV has several 
disadvantages compared to the GVT. The foremost disadvantage of the SSV 
is how easily it can be irreparably damaged when struck by a subject 
vehicle during testing, particularly at high relative velocities. While 
NHTSA has tried to address this issue by attaching a foam bumper to the 
rear of the SSV to reduce the peak forces resulting from an impact by 
the subject vehicle, the SSV can still easily be damaged to a point 
where it can no longer be used if the relative impact speed is 
sufficiently high (i.e., >40 km/h (25 mph), which is much lower than 
the maximum relative impact speed of 80 km/h (50 mph) potentially 
encountered during the AEB tests performed at the maximum relative 
speeds proposed in this notice). Also, unlike the GVT, which has its 
movement controlled by precise programming and closed loop control, the 
SSV moves along a visible monorail secured to the test surface, which 
may be visible to a camera-based AEB system.
    In addition to the vehicle test device specifications, NHTSA seeks 
comment on specifying a set of real vehicles to be used as vehicle test 
devices in AEB testing. UN ECE Regulation No. 152 specifies that the 
lead vehicle be either a regular high-volume passenger sedan or a 
``soft target'' meeting the specifications of ISO 19206-1:2018.\248\ UN 
ECE regulation does not require the use of real vehicles as targets, 
but rather offers them as an alternative to manufacturers to homologate 
their systems, at their choice. Although NHTSA has tentatively 
concluded that the specification in UN ECE Regulation No. 152 of any 
high-volume passenger sedan is not sufficiently specific for an FMVSS, 
NHTSA seeks comment on whether it should create a list of vehicles from 
which NHTSA could choose a lead vehicle for testing. Unlike the UN ECE 
regulation, which provides flexibility to manufacturers, inclusion of a 
list of vehicles would provide flexibility to the agency in the 
assessment of the performance of AEB systems. Such a list would be in 
addition to the vehicle test device proposed in this document, to 
provide assurance of vehicle performance with a wider array of lead 
vehicles. For example, the list could include the highest selling 
vehicle models in 2020.
---------------------------------------------------------------------------

    \248\ U.N. Regulation No. 152, E/ECE/TRANS/505/Rev.3/Add.151/
Amend.1 (Nov. 4, 2020), available at https://unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2020/R152am1e.pdf.
---------------------------------------------------------------------------

    Using actual vehicles has various challenges, including the 
potential for risk to individuals conducting the tests and damage to 
the vehicles involved, and assuring a safe testing environment that 
could encounter high energy collisions between real vehicles in cases 
of poor AEB system performance or AEB or test equipment malfunctions. 
NHTSA seeks comment on the utility and feasibility of test laboratories 
safely conducting AEB tests with real vehicles, such as through 
removing humans from test vehicles and automating scenario execution, 
and how laboratories would adjust testing costs to factor in the risk 
of damaged vehicles.
    Beyond the practical safety limits and cost of testing described 
above, managing a list of relevant lead vehicles would require the 
standard to be updated periodically to keep pace with the vehicle fleet 
and to ensure that lead vehicles are available years after a final 
rule. NHTSA seeks comments on the merits and potential need for testing 
using real vehicles, in addition to using a vehicle test device, as 
well as challenges, limitations, and incremental costs of such.

IX. Proposed Effective Date Schedule

    NHTSA is proposing that, within four years after publication of a 
final rule, all requirements for AEB would be applicable. Most 
requirements would have to be met within three years of the date of 
publication of the final rule. 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.
    NHTSA anticipates that nearly all vehicles subject to this proposal 
would already have the hardware capable of meeting the proposed 
requirements by the effective date of a final rule. An AEB system 
requires sensing, perception, warning hardware, and electronically 
modulated braking subsystems. The perception subsystem is comprised of 
computer software that analyzes information provided by the sensors and 
computational hardware to process the code. NHTSA anticipates that 
manufacturers will need time to build code that analyses the frontal 
view of the vehicle in a way that achieves the requirements of this 
proposed rule.
    NHTSA has found that some manufacturers have already built systems 
that are capable of meeting some of the scenarios that are proposed. 
Therefore, for all lead vehicle AEB, PAEB daylight, PAEB darkness with 
upper beam headlamps, and most PAEB darkness with lower beam headlamps 
activated, NHTSA proposes a three-year lead time for manufacturers to 
build the needed software capabilities. NHTSA proposes a four-year lead 
time for the remaining higher speed PAEB scenarios. NHTSA expects 
manufacturers to create any new code needed to meet the second stage 
lead time requirements as well as to modify existing vehicle equipment 
such as headlamps to support the functionality of PAEB in darkness.

[[Page 38708]]

    NHTSA is concerned about the potential costs and practicability 
burdens imposed on manufacturers. Given that darkness pedestrian 
avoidance technology is new, the agency believes that more time should 
be afforded to manufacturers to refine PAEB systems to meet the crash 
avoidance requirements for the higher end of the speed range in 
darkness conditions, compared to lead vehicle avoidance or lower speed 
pedestrian avoidance. The agency is also aware that implementing new 
technology outside of the normal vehicle redesign cycle can increase 
costs of implementation.
    With these considerations, NHTSA is proposing a split compliance 
schedule. For requirements other than those proposed for the darkness 
pedestrian avoidance requirements at higher speeds, NHTSA proposes an 
effective date of the first September 1st that is at least three years 
from the date of publication of a final rule. The proposed schedule 
then requires full compliance for all vehicles manufactured on or after 
the first September 1st four years after publication of a final rule.

X. Summary of Estimated Effectiveness, Cost, and Benefits

    NHTSA's assessment of available safety data indicates that between 
2016 and 2019, light vehicles averaged 1.12 million rear-impact crashes 
annually. These crashes resulted in an annual average of 394 
fatalities, 142,611 non-fatal injuries, and an additional 1.69 million 
damaged vehicles. Additionally, between 2016 and 2019, an average of 
approximately 23 thousand crashes annually could potentially have been 
addressed by PAEB. These crashes resulted in an annual average of 2,642 
pedestrian fatalities and 17,689 non-fatal injuries.

A. Target Population

    The target population for the lead vehicle AEB analysis includes 
two-vehicle, rear-end light vehicle crashes and their resulting 
occupant fatalities and non-fatal injuries. FARS is used to obtain the 
target population for fatalities and CRSS is used to obtain the target 
population for property damage only crashes and occupant injuries. The 
target population includes two-vehicle light-vehicle to light-vehicle 
crashes in which the manner of collision is a rear-end crash and the 
first harmful event was a collision with a motor vehicle in transport. 
Further refinement includes limiting the analysis to crashes where the 
striking vehicle was traveling straight ahead prior to the collision at 
a speed less than 90 mph (145 km/h) and the struck vehicle was either 
stopped, moving, or decelerating.

                                               Table 39--Light Vehicle to Light Vehicle Target Population
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                       Injuries
     Light vehicle to light vehicle target        Crashes        PDOs    -------------------------------------------------------------------  Fatalities
                  population                                                MAIS1      MAIS2      MAIS3      MAIS4      MAIS5     MAIS 1-5
--------------------------------------------------------------------------------------------------------------------------------------------------------
All Conditions................................   1,119,470    1,692,678    130,736      9,364      1,942        256         57     142,611          394
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The target population for the PAEB analysis considered only light 
vehicle crashes that included a single vehicle and pedestrian in which 
the first injury-causing event was contact with a pedestrian. The area 
of initial impact was limited to the front of the vehicle, specified as 
clock points 11, 12, and 1, and the vehicle's pre-event movement was 
traveling in a straight line. These crashes were then categorized as 
either the pedestrian crossing the vehicle path or along the vehicle 
path. The crashes are inclusive of all light, road surface, and weather 
conditions to capture potential crashes, fatalities, and injuries in 
real world conditions. Data elements listed as ``unknown'' were 
proportionally allocated, as needed.

                                       Table 40--Target Population of Pedestrian Fatalities and Non-Fatal Injuries
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                 Injuries
        Light vehicle to pedestrian target  population        ------------------------------------------------------------------------------  Fatalities
                                                                  MAIS 1       MAIS 2       MAIS 3       MAIS 4       MAIS 5      MAIS 1-5
--------------------------------------------------------------------------------------------------------------------------------------------------------
All Scenarios................................................       13,894        3,335        1,541          300           75       19,511        2,508
Crossing Path................................................       12,637        3,087        1,442          284           71       17,522        2,083
Along Path...................................................        1,257          248           98           16            4        1,622          425
--------------------------------------------------------------------------------------------------------------------------------------------------------

B. Lead Vehicle AEB System Effectiveness

    Lead vehicle AEB system effectiveness was determined based on the 
expected injury risk reduction applied to current crashes resulting in 
injuries or fatalities. The target population was split into three 
groups corresponding to the three lead vehicle test scenarios (lead 
vehicles stopped, moving, and decelerating). The crashes in these 
scenarios were further categorized into two sub-groups: Those in which 
the striking vehicle driver did not apply the brakes prior to impact 
and those where the striking vehicle driver applied the brakes as an 
avoidance maneuver. The baseline for the system effectiveness analysis 
assumed that the striking vehicle in the control group is not equipped 
with FCW or any AEB functionality. For the treatment group, NHTSA 
predicted the crash outcomes if the striking vehicle were equipped with 
an AEB system meeting the proposed performance requirements.
    For crashes where the striking vehicle's operator did not apply the 
brakes, the initial event treatment section has two stages. The first 
stage covers when FCW activates, and the second stage covers how the 
driver reacts to the FCW warning. Depending on whether the striking 
vehicle driver is predicted to react to the warning or not, the second 
stage models how the vehicle intervenes. If the striking vehicle driver 
reacts to the FCW and applies the brakes, the vehicle was modeled to 
provide supplemental braking. If the striking vehicle driver was 
predicted to not apply the brakes, the vehicle was modeled to apply the 
brakes automatically.
    Similarly, for cases where the striking vehicle driver applied the 
brakes according to the crash database, the initial treatment section 
has two stages. The first stage models the driver's reaction to FCW and 
the second stage

[[Page 38709]]

models supplemental braking (there are no conditions for which the 
driver is modeled not to apply the brakes in this situation because 
NHTSA does not anticipate that an FCW will decrease the probability of 
a driver applying the brakes). For cases where the driver applied the 
brakes, it was assumed that, in response to a forward collision 
warning, the driver would apply the brakes sooner compared to the crash 
database and that the resulting deceleration would be greater as a 
result of supplemental braking.
    Although NHTSA evaluated the crash data assuming the striking 
vehicles were not equipped with any AEB functionality, NHTSA does 
anticipate that lead vehicle AEB systems will have substantial 
voluntary market penetration, though at lower performance level than 
the proposed requirements in this NPRM. Therefore, the baseline (what 
the world would look like in the absence of the proposed regulation) 
takes into account voluntary installation of AEB. The baseline is 
incorporated by evaluating injury risk based on the expected difference 
in vehicle performance between a baseline vehicle and a vehicle meeting 
the proposed requirements. System effectiveness is estimated based on 
the calculated difference of the vehicle striking speed between the 
baseline and proposed rule and the difference in injury risk for each 
group and sub-group described above.

C. PAEB System Effectiveness

    To estimate PAEB system effectiveness, the target populations for 
along path and crossing path were further grouped by vehicle travel 
speed.
    NHTSA assumes that a PAEB system meeting the proposed requirements 
would recognize a pedestrian standing or moving along the same 
longitudinal path as the vehicle and be able to identify the speed 
differential between the two. NHTSA also estimates that the PAEB 
system's capabilities include reaching a stop 55 centimeters in front 
of the pedestrian. Thus, in the absence of external mitigating factors 
(the impacts of these factors are included later in the analyses), 
NHTSA estimates that PAEB would prevent all fatalities along path 
scenarios when activated within the operational speed range up to 45 
mph (73 km/h).
    For pedestrian crossing path crashes, NHTSA first estimated the 
distribution of collision by the location along the front of the 
vehicle at which the pedestrians were struck. This step establishes the 
time in which the pedestrian is within the path of the vehicle for a 
crossing path situation. This timing is important for NHTSA to model 
the PAEB system's ability to avoid or mitigate the crash (very short 
times do not provide much time for the PAEB system to react and thus 
the reduction in speed before the impact is low). After this, the 
effectiveness of a PAEB system that meets the proposed requirements is 
established for each travel speed.
    To account for external physical factors impeding PAEB-braking 
system effectiveness, NHTSA adjusted the estimated fatalities prevented 
and non-fatal injuries that would be mitigated by PAEB downward by 10 
percent. This assumption represents limitations associated with factors 
such as tire traction and pedestrian visibility due to inclement 
weather, contaminants on the roadway, changes in vehicle balance 
affecting traction, and poor tire and road maintenance.

D. Fatalities Avoided and Injuries Mitigated

    Table 41 presents the safety benefits associated with the proposed 
rule. As a result of the proposed rule, NHTSA estimates that a total of 
362 fatalities would be prevented, and 24,321 non-fatal (MAIS 1-5) 
injuries would be mitigated over the course of one vehicle model year's 
lifetime.

           Table 41--Summary of Safety Benefits: Fatalities Prevented and Non-Fatal Injuries Mitigated
----------------------------------------------------------------------------------------------------------------
                          Category                             Lead vehicle AEB        PAEB            Total
----------------------------------------------------------------------------------------------------------------
Non-fatal Injuries (MAIS 1-5)...............................              21,649           2,672          24,321
Fatalities..................................................                 124             238             362
----------------------------------------------------------------------------------------------------------------

    The agency considers these estimates to be conservative because 
some benefits of the proposed rule may not be quantified. The target 
population does not include multiple-vehicle rear-end crashes. AEB is 
also likely to be effective at reducing some rear-end crashes where the 
struck vehicle is something other than a light vehicle, such as a heavy 
vehicle or motorcycle. Additionally, these estimates are influenced by 
voluntary adoption of AEB. If voluntary performance levels are lower 
than the agency estimates, the benefits of the rule will be higher than 
estimated.

E. Costs

    The analysis makes use of annual sales data between calendar year 
2011-2020 to estimate the number of vehicles subject to the proposed 
rule. Table 42 presents the annual sales of new light vehicles for 2011 
through 2020. Over the ten-year period, an average of 15.7 million 
light vehicles were sold annually, of which approximately 40 percent 
were cars and 60 percent were light trucks.

                                  Table 42--Annual Sales of New Light Vehicles
                                                   [Thousands]
----------------------------------------------------------------------------------------------------------------
                                                                                                    Total light
                            Year                                     Cars          Light trucks    vehicle sales
----------------------------------------------------------------------------------------------------------------
2011........................................................               6,093           6,449          12,542
2012........................................................               7,245           6,975          14,220
2013........................................................               7,586           7,693          15,279
2014........................................................               7,708           8,484          16,192
2015........................................................               7,529           9,578          17,107
2016........................................................               6,883          10,296          17,179
2017........................................................               6,089          10,738          16,827
2018........................................................               5,310          11,609          16,919
2019........................................................               4,720          11,911          16,630

[[Page 38710]]

 
2020........................................................               3,402          10,712          14,114
                                                             ---------------------------------------------------
    Annual Average..........................................               6,257           9,445          15,701
    (% of total LV sales)...................................              (39.8)          (60.2)           (100)
----------------------------------------------------------------------------------------------------------------

    Because common hardware is used across lead vehicle AEB and PAEB 
systems, specific system functionality can be achieved through upgraded 
software. Therefore, the incremental cost associated with this proposed 
rule reflects the cost of a software upgrade that would allow current 
systems to achieve lead vehicle AEB and PAEB functionality that meets 
the requirements specified in the proposed rule. The incremental cost 
per vehicle is estimated at $82.15 for each design cycle change of the 
model. When accounting for design cycles and annual sales of new light 
vehicles, the total annual cost associated with the proposed rule is 
approximately $282.16 million in 2020 dollars.

                                           Table 43--Total Annual Cost
----------------------------------------------------------------------------------------------------------------
                                                  Number of           Per vehicle cost
                   Category                       vehicles    -------------------------------- Total annual cost
                                                 (thousands)    Design cycle       Annual          (millions)
----------------------------------------------------------------------------------------------------------------
Cars.........................................           6,257          $82.15          $27.38            $171.32
Light Trucks.................................           9,445                           11.74             110.84
                                              ------------------------------------------------------------------
    Total....................................          15,701  ..............  ..............             282.16
----------------------------------------------------------------------------------------------------------------
Note: Values may not sum due to rounding.

F. Cost-Effectiveness

    This proposed rule is highly cost effective. Based on cost-
effectiveness and benefit-cost analyses, it is expected that society 
would be better off as a result of this proposed rule. When discounted 
at three and seven percent, the cost per equivalent life saved under 
the proposed rule ranges from $0.50 to $0.62 million. Because the cost 
per equivalent life saved is less than the comprehensive economic cost 
of a fatality, the proposed rule is considered to be cost-
effective.\249\ Furthermore, when discounted at three and seven 
percent, the net benefits associated with the proposed rule are 
estimated at approximately $6.52 and $5.24 billion, respectively. 
Positive net benefits indicate that the proposed rule generates a net 
benefit to society.
---------------------------------------------------------------------------

    \249\ The PRIA presents the Value of a Statistical Life as $11.6 
million based on the ``Revised Departmental Guidance, Treatment of 
Value of Preventing Fatalities and Injuries in Preparing Economic 
Analyses'', March 2021.

                                                         Table 44--Summary of Costs and Benefits
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                     Benefits                                                      Cost per equivalent life     Net benefits (millions)
-----------------------------------------------------------------------------------                    saved (millions)      ---------------------------
                                                            Monetized benefits       Total cost  ----------------------------
                                                                (millions)           (millions)
                 Equivalent fatalities                 ----------------------------                    3%            7%            3%            7%
                                                             3%            7%
--------------------------------------------------------------------------------------------------------------------------------------------------------
675...................................................       $6,802        $5,518       $282.16         $0.50         $0.62        $6,520        $5,235
--------------------------------------------------------------------------------------------------------------------------------------------------------

G. Comparison of Regulatory Alternatives

    To explore fully other possible rulemaking options, the agency 
examined a variety of combinations of performance requirements, with 
greater and lesser stringency than the preferred alternative. NHTSA 
evaluated regulatory alternatives for this rulemaking. These regulatory 
options were: (1) Requiring light vehicles to meet the proposed lead 
vehicle AEB requirements only (no requirements for PAEB), (2) PAEB 
systems requirements only during daylight conditions (no change to the 
lead vehicle AEB requirements in the proposed rule), and (3) adding 
PAEB requirements in turning scenarios in addition to the requirements 
proposed in this NPRM (no change to the lead vehicle AEB requirements 
in the proposed rule). The last option, adding PAEB requirements in 
turning scenarios, is the only option that is expected to require new 
hardware in addition to software to cover a wider field of view when 
the vehicle is turning. The added sensors contributed to the higher 
projected cost per vehicle and the low anticipated benefits from adding 
these scenarios contributed to the higher estimated cost per equivalent 
life saved shown in Table 45. When comparing cost-effectiveness and 
benefit-cost measures across regulatory options, the proposed rule is 
the most cost-effective option and also offers the highest net 
benefits.

[[Page 38711]]



                                  Table 45--Summary of Regulatory Alternatives
----------------------------------------------------------------------------------------------------------------
                                                              Cost per equivalent life   Net benefits (millions)
                                                                  saved (millions)     -------------------------
      Regulatory options        Relative to preferred option --------------------------
                                                                   3%           7%           3%           7%
----------------------------------------------------------------------------------------------------------------
Option #1: Lead Vehicle AEB     Less Stringent..............        $0.88        $1.09       $3,650       $2,910
 Requirements.
Option #2: Daylight only PAEB.  Less Stringent..............         0.71         0.87        4,594        3,674
Option #3: Proposed Rule......  Preferred Option............         0.50         0.62        6,520        5,235
Option #4: Add turning          More Stringent..............         3.13         3.86        5,447        4,062
 scenarios for PAEB.
----------------------------------------------------------------------------------------------------------------

XI. Regulatory Notices and Analyses

Executive Orders 12866, 13563, and 14094 and DOT Regulatory Policies 
and Procedures

    The agency has considered the impact of this rulemaking action 
under Executive Order (E.O.) 12866, E.O. 13563, E.O. 14094, and the 
Department of Transportation's regulatory procedures. This rulemaking 
is considered ``(3)(f)(1) significant'' and was reviewed by the Office 
of Management and Budget under E.O. 12866, ``Regulatory Planning and 
Review,'' as amended by E.O. 14094, ``Modernizing Regulatory Review.'' 
It is expected to have an annual effect on the economy of $200 million 
or more. NHTSA has prepared a preliminary regulatory impact analysis 
that assesses the cost and benefits of this proposed rule, which has 
been included in the docket listed at the beginning of this NPRM. The 
benefits, costs, and other impacts of this NPRM are summarized in the 
prior section of this NPRM.

Regulatory Flexibility Act

    The Regulatory Flexibility Act of 1980, as amended, requires 
agencies to evaluate the potential effects of their proposed and final 
rules on small businesses, small organizations, and small governmental 
jurisdictions. I certify that this NPRM would not have a significant 
economic impact on a substantial number of small entities.
    The PRIA discusses the economic impact of the proposed rule on 
small vehicle manufacturers, of which NHTSA is aware of 12. NHTSA 
believes that this proposed rule would not have a significant economic 
impact on these manufacturers. Much of the work developing and 
manufacturing AEB system components would be conducted by suppliers. 
Although the final certification would be made by the manufacturer, 
this proposal would allow one additional year for small-volume 
manufacturers to comply with any requirement. This approach is similar 
to the approach we have taken in other rulemakings in recognition of 
manufacturing differences between larger and smaller manufacturers. 
This NPRM proposes a phased compliance schedule to attain lead vehicle 
AEB and PAEB safety benefits as soon as practicable, while providing 
more time to develop technology improvements, such as those needed to 
meet darkness PAEB requirements. As the countermeasures are developed, 
AEB suppliers would likely supply larger vehicle manufacturers first, 
before small manufacturers. This NPRM recognizes this and proposes to 
provide smaller manufacturers flexibility, so they have time to obtain 
the equipment and work with the suppliers after the demands of the 
larger manufacturers are met.
    This proposal may also affect final stage manufacturers, many of 
whom would be small businesses. However, it is NHTSA's understanding 
that final stage manufacturers rarely make modifications to a vehicle's 
braking system and instead rely upon the pass-through certification 
provided by a first-stage manufacturers. As with small-volume 
manufacturers, final stage manufacturers would be provided with one 
additional year to comply with any requirement.
    Additional information concerning the potential impacts of this 
proposal on small business is presented in the PRIA accompanying this 
proposal.

National Environmental Policy Act

    The National Environmental Policy Act of 1969 (NEPA) \250\ requires 
Federal agencies to analyze the environmental impacts of proposed major 
Federal actions significantly affecting the quality of the human 
environment, as well as the impacts of alternatives to the proposed 
action.\251\ The Council on Environmental Quality (CEQ) directs federal 
agencies to prepare an environmental assessment for a proposed action 
``that is not likely to have significant effects or when the 
significance of the effects is unknown.'' \252\ When a Federal agency 
prepares an environmental assessment, CEQ's NEPA implementing 
regulations require it to (1) ``[b]riefly provide sufficient evidence 
and analysis for determining whether to prepare an environmental impact 
statement or a finding of no significant impact;'' and (2) ``[b]riefly 
discuss the purpose and need for the proposed action, alternatives . . 
., and the environmental impacts of the proposed action and 
alternatives, and include a listing of agencies and persons 
consulted.'' \253\
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    \250\ 42 U.S.C. 4321-4347.
    \251\ 42 U.S.C. 4332(2)(C).
    \252\ 40 CFR 1501.5(a).
    \253\ 40 CFR 1501.5(c).
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    This section serves as NHTSA's Draft Environmental Assessment (EA). 
In this Draft EA, NHTSA outlines the purpose and need for the proposed 
rulemaking, a reasonable range of alternative actions the agency could 
adopt through rulemaking, and the projected environmental impacts of 
these alternatives.

Purpose and Need

    This NPRM sets forth the purpose of and need for this action. In 
this NPRM, NHTSA 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 rear-end (lead vehicle AEB) and 
pedestrian crashes (PAEB). As explained earlier in this preamble, the 
AEB system improves safety by using 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, thereby detecting and reacting to an imminent 
crash with a lead vehicle or pedestrian. This NPRM promotes NHTSA's 
goal to reduce the frequency and severity of crashes described in the 
summary of the crash problem discussed earlier in the NPRM, 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 
(BIL)

[[Page 38712]]

directing the Department to promulgate such a rule.

Alternatives

    NHTSA has considered four regulatory alternatives for the proposed 
action and a ``no action alternative.'' Under the no action 
alternative, NHTSA would not issue a final rule requiring that vehicles 
be equipped with systems that meet minimum specified performance 
requirements, and manufacturers would continue to add AEB systems 
voluntarily. However, since the BIL directs NHTSA to promulgate a rule 
that would require that all passenger vehicles be equipped with an AEB 
system, the no action alternative is not a permissible option. 
Alternative 1 considers requirements specific to lead vehicle AEB only. 
Alternative 2 includes the lead vehicle AEB requirements in Alternative 
1 and a requirement in which PAEB is only required to function in 
daylight conditions. Alternative 3, the preferred alternative, 
considers requirements for lead vehicle AEBs and PAEB requirements in 
both daylight and darkness conditions. Alternative 4 considers a more-
stringent requirement in which PAEB would be required to provide 
pedestrian protections in turning scenarios (no change to the lead 
vehicle AEB requirements in the proposed rule).
    NHTSA has also considered the International Organization for 
Standardization (ISO) standards, SAE International standards, the 
Economic Commission for Europe (ECE) standards, test procedures used by 
NHTSA's New Car Assessment Program (NCAP) and Euro NCAP, and more which 
are described above in this preamble and accompanying appendixes. In 
the proposed rule, NHTSA incorporates aspects of the test procedures 
and standards mentioned here, but departs from them in numerous and 
significant ways.

Environmental Impacts of the Proposed Action and Alternatives

    This proposed rule is anticipated to result in the employment of 
sensor technologies and sub-systems on light vehicles that work 
together to sense when a 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. 
This proposed rule is also anticipated to improve safety by mitigating 
the amount of fatalities, non-fatal injuries, and property damage that 
would result from crashes that could potentially be prevented or 
mitigated because of AEB. As a result, the primary environmental 
impacts \254\ that could potentially result from this rulemaking are 
associated with: greenhouse gas emissions and air quality, 
socioeconomics, public health and safety, solid waste/property damage/
congestion, and hazardous materials. Consistent with CEQ regulations 
and guidance, this EA discusses impacts in proportion to their 
potential significance. The effects of the proposed rulemaking that 
were analyzed further are summarized below.
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    \254\ NHTSA anticipates that the proposed action and 
alternatives would have negligible or no impact on the following 
resources and impact categories, and therefore has not analyzed them 
further: topography, geology, soils, water resources (including 
wetlands and floodplains), biological resources, resources protected 
under the Endangered Species Act, historical and archeological 
resources, farmland resources, environmental justice, and Section 
4(f) properties.
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Greenhouse Gas Emissions and Air Quality
    NHTSA has previously recognized that additional weight required by 
FMVSS could potentially negatively impact the amount of fuel consumed 
by a vehicle, and accordingly result in greenhouse gas emissions or air 
quality impacts from criteria pollutant emissions. Atmospheric 
greenhouse gases (GHGs) affect Earth's surface temperature by absorbing 
solar radiation that would otherwise be reflected back into space. 
Carbon dioxide (CO2) is the most significant greenhouse gas 
resulting from human activity. Motor vehicles emit CO2 as 
well as other GHGs, including methane and nitrous oxides, in addition 
to criteria pollutant emissions that negatively affect public health 
and welfare.
    Additional weight added to a vehicle, like added hardware from 
safety systems, can cause an increase in vehicle fuel consumption and 
emissions. An AEB system requires the following hardware: sensing, 
perception, warning hardware, and electronically modulated braking 
subsystems. As discussed in the preamble and the PRIA, NHTSA 
anticipates that under the no-action alternative and Alternatives 1-3, 
nearly all vehicles subject to the proposal would already have all of 
the hardware capable of meeting the proposed requirements by the 
effective date of a final rule. For all alternatives, NHTSA assumes 
that manufacturers will need time to build code that analyses the 
frontal view of the vehicle (i.e., manufacturers would need to upgrade 
the software for the perception subsystem) in a way that achieves the 
requirements of this proposed rule, but no additional hardware would 
need to be added. Alternative 4 does include an assumption that two 
cameras will be added; however, based on weight assumptions included in 
studies cited in the PRIA, that weight impact would be minimal, at 
approximately 1570 grams, or 3.46 pounds. NHTSA has previously 
estimated that a 3-4-pound increase in vehicle weight is projected to 
reduce fuel economy by 0.01 mpg.\255\ Accordingly, while Alternatives 
1-3 would not have any fuel economy penalty because no hardware would 
be added, Alternative 4 would potentially have a negligible fuel 
economy penalty.
---------------------------------------------------------------------------

    \255\ Final Regulatory Impact Analysis, Corporate Average Fuel 
Economy for MYs 2012-2016 Passenger Cars and Light Trucks, Table IV-
5 (March 2010).
---------------------------------------------------------------------------

    Pursuant to the Clean Air Act (CAA), the U.S. Environmental 
Protection Agency (EPA) has established a set of National Ambient Air 
Quality Standards (NAAQS) for the following ``criteria'' pollutants: 
carbon monoxide (CO), nitrogen dioxide (NO2), ozone, particulate matter 
(PM) less than 10 micrometers in diameter (PM10), PM less 
than 2.5 micrometers in diameter (PM2.5), sulfur dioxide 
(SO2), and lead (Pb). The NAAQS include ``primary'' 
standards and ``secondary'' standards. Primary standards are intended 
to protect public health with an adequate margin of safety. Secondary 
standards are set at levels designed to protect public welfare by 
accounting for the effects of air pollution on vegetation, soil, 
materials, visibility, and other aspects of the general welfare. Under 
the General Conformity Rule of the CAA,\256\ EPA requires a conformity 
determination when a Federal action would result in total direct and 
indirect emissions of a criteria pollutant or precursor originating in 
nonattainment or maintenance areas equaling or exceeding the emissions 
thresholds specified in 40 CFR 93.153(b)(1) and (2). However, the 
General Conformity Rule does not require a conformity determination for 
Federal actions that are ``rulemaking and policy development and 
issuance,'' such as this action.\257\ Therefore, NHTSA has determined 
it is not required to perform a conformity analysis for this action.
---------------------------------------------------------------------------

    \256\ Section 176(c) of the CAA, codified at 42 U.S.C. 7506(c); 
To implement CAA Section 176(c), EPA issued the General Conformity 
Rule (40 CFR part 51, subpart W and part 93, subpart B).
    \257\ 40 CFR 93.153(c)(2)(iii).
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Socioeconomics
    The socioeconomic impacts of the proposed rulemaking would be 
primarily felt by vehicle manufacturers, light vehicle drivers, 
passengers, and pedestrians on the road that would

[[Page 38713]]

otherwise be killed or injured in light vehicle crashes. NHTSA 
conducted a detailed assessment of the economic costs and benefits of 
establishing the new rule in its PRIA. The main economic benefits come 
primarily from the reduction in fatalities and non-fatal injuries 
(safety benefits). Reductions in the severity of motor vehicle crashes 
would be anticipated to have corresponding reductions in costs for 
medical care, emergency services, insurance administrative costs, 
workplace costs, and legal costs due to the fatalities and injuries 
avoided. Other socioeconomic factors discussed in the PRIA that would 
affect these parties include software costs and property damage 
savings. Overall, Alternative 1 is anticipated to have societal net 
benefits of $2.91 to $3.65 billion, Alternative 2 is anticipated to 
have societal net benefits of $3.67 to $4.59 billion, Alternative 3 
(the preferred alternative) is anticipated to have societal net 
benefits of $5.24 to $6.52 billion, and Alternative 4 is anticipated to 
have societal net benefits of $4.06 to $5.45 billion. The PRIA 
discusses this information in further detail.
Public Health and Safety
    The affected environment for public health and safety includes 
roads, highways and other driving locations used by all light vehicle 
drivers, other drivers, passengers in light vehicles and other motor 
vehicles, and pedestrians or other individuals who could be injured or 
killed in crashes involving the vehicles regulated by the proposed 
action. In the PRIA, the agency determined the impacts on public health 
and safety by estimating the reduction in fatalities and injuries 
resulting from the decreased crash severity due to the use of AEB 
systems under the four action alternatives. Under Alternative 1, it is 
expected that the addition of a less stringent requirement that only 
specifies requirements for lead vehicle AEB would result each year in 
260 to 320 equivalent lives saved. Under Alternative 2, it is expected 
that the less-stringent requirement, in which PAEB is only required to 
function in daylight conditions, would result each year in 323 to 398 
equivalent lives saved. Under Alternative 3 (the preferred 
alternative), it is expected that the regulatory option would result 
each year in 454 to 559 equivalent lives saved. Finally, under 
Alternative 4, it is expected that the addition of more stringent 
requirements in which PAEB would be required to provide pedestrian 
protections in turning scenarios would result each year in 490 to 604 
equivalent lives saved. The PRIA discusses this information in further 
detail.
Solid Waste/Property Damage/Congestion
    Vehicle crashes can generate solid wastes and release hazardous 
materials into the environment. The chassis and engines, as well as 
associated fluids and components of automobiles and the contents of the 
vehicles, can all be deemed waste and/or hazardous materials. Solid 
waste can also include damage to the roadway infrastructure, including 
road surface, barriers, bridges, and signage. Hazardous materials are 
substances that may pose a threat to public safety or the environment 
because of their physical, chemical, or radioactive properties when 
they are released into the environment, in this case as a result of a 
crash.
    NHTSA's proposed rulemaking is projected to reduce the amount and 
severity of light vehicle crashes, and therefore may reduce the 
quantity of solid waste, hazardous materials, and other property damage 
generated by light vehicle crashes in the United States. The addition 
of an AEB system may also result in reduced damage to the vehicles and 
property, as well as reduced travel delay costs due to congestion. This 
is especially the case in ``property damage only'' crashes, where no 
individuals are injured or killed in the crash, but there may be damage 
to the vehicle or whatever is impacted by it. NHTSA estimates that 
based off data from 2016-2019 alone, an average of 1.12 million rear-
impact crashes involving light vehicles occurred annually. These 
crashes resulted in an annual average of 394 fatalities, 142,611 non-
fatal injuries, and approximately 1.69 million property damage only 
vehicles (PDOV).
    Less solid waste translates into cost and environmental savings 
from reductions in the following areas: (1) transport of waste 
material, (2) energy required for recycling efforts, and (3) landfill 
or incinerator fees. Less waste will result in beneficial environmental 
effects through less GHG emissions used in the transport of it to a 
landfill, less energy used to recycle the waste, less emissions through 
the incineration of waste, and less point source pollution at the scene 
of the crash that would result in increased emissions levels or 
increased toxins leaking from the crashed vehicles into the surrounding 
environment.
    The addition of an AEB system may also result in reduced post-crash 
environmental effects from congestion. As discussed in the PRIA, 
NHTSA's monetized benefits are calculated by multiplying the number of 
non-fatal injuries and fatalities mitigated by their corresponding 
``comprehensive costs.'' The comprehensive costs include economic costs 
that are external to the value of a statistical life (VSL) costs, such 
as emergency management services or legal costs, and congestion costs. 
NHTSA has recognized that motor vehicle crashes result in congestion 
that has both socioeconomic and environmental effects. These 
environmental effects include ``wasted fuel, increased greenhouse gas 
production, and increased pollution as engines idle while drivers are 
caught in traffic jams and slowdowns.'' \258\ NHTSA's monetized 
benefits therefore do include a quantified measure of congestion 
avoidance. NHTSA did not calculate congestion effects specifically for 
each regulatory alternative, however, because comprehensive costs are a 
discrete cost applied to non-fatal injuries and fatalities at the same 
rate, we can conclude that there are increasing benefits associated 
with fewer crashes, and specifically decreased congestion, as the 
monetized benefits increase across regulatory alternatives. To the 
extent that any regulatory option for AEB results in fewer crashes and 
accordingly higher monetized benefits, there would be fewer congestion-
related environmental effects.
---------------------------------------------------------------------------

    \258\ Blincoe, L.J., Miller, T.R., Zaloshnja, E., & Lawrence, 
B.A. (2015, May). The economic and societal impact of motor vehicle 
crashes, 2010. (Revised) (Report No. DOT HS 812 013). Washington, 
DC: National Highway Traffic Safety Administration.
---------------------------------------------------------------------------

    NHTSA has tentatively concluded that under the agency's proposal, 
the economic benefits resulting from improved safety outcomes, property 
damage savings, fuel savings, and GHG reductions would not only limit 
the negative environmental impacts caused by additional solid waste/
property damage due to crashes but also would limit such effects. 
Similarly, while the potential degree of hazardous materials spills 
prevented due to the reduction of crash severity and crash avoidance 
expected from the rulemaking has not specifically been analyzed in the 
PRIA or NPRM, the addition of the AEB system is projected to reduce the 
amount and severity of light vehicle crashes and may improve the 
environmental effects with respect to hazardous material spills. While 
the PRIA does not specifically quantify these impact categories, in 
general NHTSA believes the benefits would increase relative to the 
crashes avoided and would be relative across the different 
alternatives. The PRIA

[[Page 38714]]

discusses information related to quantified costs and benefits of 
crashes, and in particular property damage due to crashes, for each 
regulatory alternative in further detail.
Cumulative Impacts
    In addition to direct and indirect effects, CEQ regulations require 
agencies to consider cumulative impacts of major Federal actions. CEQ 
regulations define cumulative impacts as the impact ``on the 
environment that result from the incremental [impact] of the action 
when added to . . . other past, present, and reasonably foreseeable 
future actions regardless of what agency (Federal or non-Federal) or 
person undertakes such other actions.'' \259\ NHTSA notes that the 
public health and safety, solid waste/property damage/congestion, air 
quality and greenhouse gas emissions, socioeconomic, and hazardous 
material benefits identified in this EA were based on calculations 
described in the PRIA, in addition to other NHTSA actions and studies 
on motor vehicle safety. That methodology required the agency to adjust 
historical figures to reflect vehicle safety rulemakings that have 
recently become effective. As a result, many of the calculations in 
this EA already reflect the incremental impact of this action when 
added to other past actions.
---------------------------------------------------------------------------

    \259\ 40 CFR 1508.1(g)(3).
---------------------------------------------------------------------------

    NHTSA's and other parties' past actions that improve the safety of 
light vehicles, as well as future actions taken by the agency or other 
parties that improve the safety of light vehicles, could further reduce 
the severity or number of crashes involving light vehicles. Any such 
cumulative improvement in the safety of light vehicles would have an 
additional effect in reducing injuries and fatalities and could reduce 
the quantity of solid and hazardous materials generated by crashes. 
With regard to vehicle fuel use that leads to criteria air pollutant 
and GHG emissions, Federal or State actions, like NHTSA's Corporate 
Average Fuel Economy standards for light duty vehicles or EPA's 
greenhouse gas and criteria pollutant emissions standards for light 
duty vehicles, may result in additional emissions reductions by light 
vehicles in the future.
Agencies and Persons Consulted
    This preamble describes the various materials, persons, and 
agencies consulted in the development of the proposal.
Finding of No Significant Impact
    Although this rule is anticipated to result in increased FMVSS 
requirements for light vehicle manufacturers, AEB systems have already 
largely been introduced by manufacturers voluntarily. The addition of 
regulatory requirements (depending on the regulatory alternative) to 
standardize the AEB systems in all vehicle models is anticipated to 
result in no or negligible fuel economy and emissions penalties (i.e., 
only Alternative 4 would potentially require additional hardware, but 
the added weight is negligible), increasing socioeconomic and public 
safety benefits as the alternatives get more stringent, and an increase 
in benefits from the reduction in solid waste, property damage, and 
congestion (including associated traffic level impacts like reduction 
in energy consumption and tailpipe pollutant emissions) from fewer 
vehicle crashes across the regulatory alternatives.
    Based on the information in this Draft EA and assuming no 
additional information or changed circumstances, NHTSA expects to issue 
a Finding of No Significant Impact (FONSI).\260\ NHTSA has tentatively 
concluded that none of the impacts anticipated to result from the 
proposed action and alternatives under consideration will have a 
significant effect on the human environment. Such a finding will be 
made only after careful review of all public comments received. A Final 
EA and a FONSI, if appropriate, will be issued as part of the final 
rule.
---------------------------------------------------------------------------

    \260\ 40 CFR 1501.6(a).
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Executive Order 13132 (Federalism)
    NHTSA has examined this NPRM pursuant to Executive Order 13132 (64 
FR 43255, August 10, 1999) and concludes that no additional 
consultation with States, local governments, or their representatives 
is mandated beyond the rulemaking process. The agency has concluded 
that the rulemaking will not have sufficient federalism implications to 
warrant consultation with State and local officials or the preparation 
of a federalism summary impact statement. The NPRM will not have 
``substantial direct effects on the States, on the relationship between 
the national government and the States, or on the distribution of power 
and responsibilities among the various levels of government.''
    NHTSA rules can preempt in two ways. First, the National Traffic 
and Motor Vehicle Safety Act contains an express preemption provision: 
When a motor vehicle safety standard is in effect under this chapter, a 
State or a political subdivision of a State may prescribe or continue 
in effect a standard applicable to the same aspect of performance of a 
motor vehicle or motor vehicle equipment only if the standard is 
identical to the standard prescribed under this chapter. 49 U.S.C. 
30103(b)(1). It is this statutory command by Congress that preempts any 
non-identical State legislative and administrative law addressing the 
same aspect of performance.
    The express preemption provision described above is subject to a 
savings clause under which compliance with a motor vehicle safety 
standard prescribed under this chapter does not exempt a person from 
liability at common law. 49 U.S.C. 30103(e). Pursuant to this 
provision, State common law tort causes of action against motor vehicle 
manufacturers that might otherwise be preempted by the express 
preemption provision are generally preserved.
    However, the Supreme Court has recognized the possibility, in some 
instances, of implied preemption of such State common law tort causes 
of action by virtue of NHTSA's rules, even if not expressly preempted. 
This second way that NHTSA rules can preempt is dependent upon there 
being an actual conflict between an FMVSS and the higher standard that 
would effectively be imposed on motor vehicle manufacturers if someone 
obtained a State common law tort judgment against the manufacturer, 
notwithstanding the manufacturer's compliance with the NHTSA standard. 
Because most NHTSA standards established by an FMVSS are minimum 
standards, a State common law tort cause of action that seeks to impose 
a higher standard on motor vehicle manufacturers will generally not be 
preempted. However, if and when such a conflict does exist--for 
example, when the standard at issue is both a minimum and a maximum 
standard--the State common law tort cause of action is impliedly 
preempted. See Geier v. American Honda Motor Co., 529 U.S. 861 (2000).
    Pursuant to Executive Order 13132 and 12988, NHTSA has considered 
whether this proposed rule could or should preempt State common law 
causes of action. The agency's ability to announce its conclusion 
regarding the preemptive effect of one of its rules reduces the 
likelihood that preemption will be an issue in any subsequent tort 
litigation. To this end, the agency has examined the nature (i.e., the 
language and structure of the regulatory text) and objectives of this 
proposed rule and finds that this rule, like many NHTSA

[[Page 38715]]

rules, would prescribe only a minimum safety standard. As such, NHTSA 
does not intend this NPRM to preempt state tort law that would 
effectively impose a higher standard on motor vehicle manufacturers 
rule. Establishment of a higher standard by means of State tort law 
will not conflict with the minimum standard adopted here. Without any 
conflict, there could not be any implied preemption of a State common 
law tort cause of action.
Civil Justice Reform
    With respect to the review of the promulgation of a new regulation, 
section 3(b) of Executive Order 12988, ``Civil Justice Reform'' (61 FR 
4729, February 7, 1996) requires that Executive agencies make every 
reasonable effort to ensure that the regulation: (1) Clearly specifies 
the preemptive effect; (2) clearly specifies the effect on existing 
Federal law or regulation; (3) provides a clear legal standard for 
affected conduct, while promoting simplification and burden reduction; 
(4) clearly specifies the retroactive effect, if any; (5) adequately 
defines key terms; and (6) addresses other important issues affecting 
clarity and general draftsmanship under any guidelines issued by the 
Attorney General. This document is consistent with that requirement.
    Pursuant to this Order, NHTSA notes as follows. The preemptive 
effect of this rulemaking is discussed above. NHTSA notes further that 
there is no requirement that individuals submit a petition for 
reconsideration or pursue other administrative proceeding before they 
may file suit in court.
Paperwork Reduction Act (PRA)
    Under the PRA of 1995, a person is not required to respond to a 
collection of information by a Federal agency unless the collection 
displays a valid OMB control number. There are no ``collections of 
information'' (as defined at 5 CFR 1320.3(c)) in this NPRM.
National Technology Transfer and Advancement Act
    Under the National Technology Transfer and Advancement Act of 1995 
(NTTAA) (Pub. L. 104-113), all Federal agencies and departments shall 
use technical standards that are developed or adopted by voluntary 
consensus standards bodies, using such technical standards as a means 
to carry out policy objectives or activities determined by the agencies 
and departments. Voluntary consensus standards are technical standards 
(e.g., materials specifications, test methods, sampling procedures, and 
business practices) that are developed or adopted by voluntary 
consensus standards bodies, such as the International Organization for 
Standardization and SAE International. The NTTAA directs us to provide 
Congress, through OMB, explanations when we decide not to use available 
and applicable voluntary consensus standards.
    NHTSA is proposing to incorporate by reference ISO and ASTM 
standards into this proposed rule. NHTSA considered several ISO 
standards and has proposed to use ISO 19206-3:2021 to specify the 
vehicle test device and a combination of ISO 19206-2:2018 and ISO 
19206-4:2020 to specify the test mannequins. NHTSA is incorporating by 
reference ASTM E1337-19, which is already incorporated by reference 
into many FMVSSs, to measure the peak braking coefficient of the 
testing surface.
    NHTSA considered SAE International Recommended Practice J3087, 
``Automatic emergency braking (AEB) system performance testing,'' which 
define the conditions for testing AEB and FCW systems. This standard 
defines test conditions, test targets, test scenarios, and measurement 
methods, but does not provide performance criteria. There is 
considerable overlap in the test setup and conditions between this 
proposed rule and the SAE standard including the basic scenarios of 
lead vehicle stopped, slower moving, and decelerating. This SAE 
recommended practice is substantially similar to the existing NCAP test 
procedures and this proposal.
    NHTSA also considered SAE International Standard J3116, ``Active 
Safety Pedestrian Test Mannequin Recommendation,'' which provides 
recommendations for the characteristics of a surrogate that could be 
used in testing of active pedestrian safety systems. NHTSA proposed to 
incorporate the ISO standard because the ISO Standard specifications 
are more widely adopted than the SAE Recommended Practice. However, 
NHTSA requests comments on whether it would be more appropriate to use 
the SAE Recommended Practice specifications because they are more 
representative of the average pedestrian fatality.
    In Appendix B of this preamble, NHTSA describes several 
international test procedures and regulations the agency considered for 
use in this NPRM. This proposed rule has substantial technical overlap 
with UNECE Regulation No. 131 and UNECE Regulation No. 152. This 
proposal and the UNECE regulations both specify a forward collision 
warning and automatic emergency braking. Several lead vehicle AEB 
scenarios are nearly identical, including the lead vehicle stopped and 
lead vehicle moving scenarios. The pedestrian crossing path scenario 
specified in UNECE Regulation No. 152 is substantially similar to this 
NPRM. As discussed in the preamble, this proposed rule differs from the 
UNECE standards in the areas of maximum test speed and the minimum 
level of required performance. This proposed rule uses higher test 
speeds and a requirement that the test vehicle avoid contact. This 
approach would increase the repeatability of the test and maximize the 
realized safety benefits of the rule.
Incorporation by Reference
    Under regulations issued by the Office of the Federal Register (1 
CFR 51.5(a)), an agency, as part of a proposed rule that includes 
material incorporated by reference, must summarize material that is 
proposed to be incorporated by reference and discuss the ways the 
material is reasonably available to interested parties or how the 
agency worked to make materials available to interested parties.
    In this NPRM, NHTSA proposes to incorporate by reference six 
documents into the Code of Federal Regulations, one of which is already 
incorporated by reference. The document already incorporated by 
reference into 49 CFR part 571 is ASTM E1337, ``Standard Test Method 
for Determining Longitudinal Peak Braking Coefficient (PBC) of Paved 
Surfaces Using Standard Reference Test Tire.'' ASTM E1337 is a standard 
test method for evaluating peak braking coefficient of a test surface 
using a standard reference test tire using a trailer towed by a 
vehicle. NHTSA uses this method in all of its braking and electronic 
stability control standards to evaluate the test surfaces for 
conducting compliance test procedures.
    NHTSA is also proposing to incorporate by reference into part 571 
SAE J2400 ``Human Factors in Forward Collision Warning System: 
Operating Characteristics and User Interface Requirements.'' SAE J2400 
is an information report that is intended as a starting point of 
reference for designers of forward collision warning systems. NHTSA 
would incorporate this document by reference solely to specify the 
location specification and symbol for a visual forward collision 
warning.
    NHTSA is proposing to incorporate by reference four ISO standards 
into 49 CFR part 596. The first of these standards is ISO 3668:2017, 
``Paints and varnishes--Visual comparison of colour of paints.'' This 
document specifies a

[[Page 38716]]

method for the visual comparison of the color of paints against a 
standard. This method would be used to verify the color of certain 
elements of the pedestrian test mannequin NHTSA is proposing to use in 
PAEB testing. Specifically, NHTSA is using these procedures in order to 
determine that the color of the hair, torso, arms, and feet of the 
pedestrian test mannequin is black and that the color of the legs are 
blue.
    NHTSA is also proposing to incorporate by reference ISO 19206-
2:2018(E), ``Road vehicles--Test devices for target vehicles, 
vulnerable road users and other objects, for assessment of active 
safety functions--Part 2: Requirements for pedestrian targets.'' This 
document addresses the specification for a test mannequin. It is 
designed to resemble the characteristics of a human, while ensuring the 
safety of the test operators and preventing damage to subject vehicles 
in the event of a collision during testing. NHTSA is referencing many, 
but not all, of the specifications of ISO 19206-2:2018(E), as discussed 
in section VIII.A of this NPRM.
    NHTSA is also proposing to incorporate by reference ISO 19206-
3:2021(E), ``Test devices for target vehicles, vulnerable road users 
and other objects, for assessment of active safety functions--Part 3: 
Requirements for passenger vehicle 3D targets.'' This document provides 
specification of three-dimensional test devices that resemble real 
vehicles. Like the test mannequin described in the prior paragraph, it 
is designed to ensure the safety of the test operators and to prevent 
damage to subject vehicles in the event of a collision during testing. 
NHTSA is referencing many, but not all, of the specifications of ISO 
19206-3:2021(e), as discussed in section VIII.B of this NPRM.
    Finally, NHTSA is proposing to incorporate by reference ISO 19206-
4:2020, ``Road vehicles--test devices for target vehicles, vulnerable 
road users and other objects, for assessment of active safety 
functions--Part 4: Requirements for bicyclists targets.'' This standard 
describes specifications for bicycle test devices, which are 
representative of adult and child sizes. However, NHTSA is not 
proposing to use a bicycle test device during testing. Rather, this 
standard is incorporated by reference solely because it contains 
specifications for color and reflectivity, including skin color, that 
NHTSA is applying to its pedestrian test mannequin.
    All standards proposed to be incorporated by reference in this NPRM 
are available for review at NHTSA's headquarters in Washington, DC, and 
for purchase from the organizations promulgating the standards. The 
ASTM standard presently incorporated by reference into other NHTSA 
regulations is also available for review at ASTM's online reading 
room.\261\
---------------------------------------------------------------------------

    \261\ https://www.astm/org/READINGLIBRARY/.
---------------------------------------------------------------------------

Unfunded Mandates Reform Act
    The Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4) requires 
agencies to prepare a written assessment of the costs, benefits, and 
other effects of proposed or final rules that include a Federal mandate 
likely to result in the expenditures by States, local or tribal 
governments, in the aggregate, or by the private sector, of more than 
$100 million annually (adjusted annually for inflation with base year 
of 1995). Adjusting this amount by the implicit gross domestic product 
price deflator for 2021 results in an estimated current value of $165 
million (2021 index value of 113.07/1995 index value of 68.60 = 1.65). 
The assessment may be included in conjunction with other assessments, 
as it is here.
    A proposed rule on lead vehicle AEB and PAEB is not likely to 
result in expenditures by State, local or tribal governments of more 
than $100 million annually. However, it is estimated to result in the 
estimated expenditure by automobile manufacturers and/or their 
suppliers of $282 million annually (estimated to be $27.38 per 
passenger car and $11.74 per light truck annually). This range in 
estimated cost impacts reflects that the estimated incremental costs 
depend on a variety of lead vehicle AEB hardware and software that 
manufacturers plan to install (in vehicles used as ``baseline'' for the 
cost estimate). The final cost will greatly depend on choices made by 
the automobile manufacturers to meet the lead vehicle AEB and PAEB test 
requirements. These effects have been discussed in this Preliminary 
Regulatory Impact Analysis in Chapter 5.3.
    The Unfunded Mandates Reform Act requires the agency to select the 
``least costly, most cost-effective or least burdensome alternative 
that achieves the objectives of the rule.'' As an alternative, the 
agency considered a full-vehicle dynamic test to evaluate the 
capability of lead vehicle AEB and PAEB systems to prevent crashes or 
mitigate the severity of crashes. Based on our experience on conducting 
vehicle tests for vehicles equipped with lead vehicle AEB and PAEB 
where we utilize a reusable surrogate target crash vehicle and test 
mannequins instead of conducting the test with an actual vehicle as the 
target, we determined that full vehicle-to-vehicle crash tests can have 
an undesired amount of variability in vehicle kinematics. Unlike 
vehicle-to-vehicle tests, the lead vehicle AEB and PAEB tests with a 
surrogate target vehicle is conducted in a well-controlled test 
environment, which results in an acceptable amount of variability. In 
addition, the agency's lead vehicle AEB and PAEB tests with surrogate 
target vehicle and pedestrian were able to reveal deficiencies in the 
system that resulted in inadequate system capability in detecting and 
activating the brakes. Therefore, we concluded that a full vehicle-to-
vehicle test would not achieve the objectives of the rule.
    In addition, the agency evaluated data across a broad range of test 
scenarios in an effort to identify the maximum range of test speeds at 
which it is feasible for test vehicles to achieve a no-contact result. 
The range of feasible speeds identified in the review was specified as 
the mandated range in the proposed rule. Thus, there are no alternative 
test procedures available that would improve the ability of 
manufacturers to achieve no-contact results. In turn, the agency 
concluded that lead vehicle AEB and PAEB systems designed to meet the 
no-contact requirement at speeds outside the ranges specified in the 
proposed rule would not achieve the objectives of the rule.
Executive Order 13609 (Promoting International Regulatory Cooperation)
    The policy statement in section 1 of E.O. 13609 states, in part, 
that the regulatory approaches taken by foreign governments may differ 
from those taken by U.S. regulatory agencies to address similar issues 
and that, in some cases, the differences between the regulatory 
approaches of U.S. agencies and those of their foreign counterparts 
might not be necessary and might impair the ability of American 
businesses to export and compete internationally. The E.O. states that, 
in meeting shared challenges involving health, safety, labor, security, 
environmental, and other issues, international regulatory cooperation 
can identify approaches that are at least as protective as those that 
are or would be adopted in the absence of such cooperation, and that 
international regulatory cooperation can also reduce, eliminate, or 
prevent unnecessary differences in regulatory requirements. NHTSA 
requests public comment on the ``regulatory approaches taken by foreign 
governments'' concerning the subject matter of this rulemaking.

[[Page 38717]]

Regulation Identifier Number
    The Department of Transportation assigns a regulation identifier 
number (RIN) to each regulatory action listed in the Unified Agenda of 
Federal Regulations. The Regulatory Information Service Center 
publishes the Unified Agenda in April and October of each year. You may 
use the RIN contained in the heading at the beginning of this document 
to find this action in the Unified Agenda.
Plain Language
    Executive Order 12866 requires each agency to write all rules in 
plain language. Application of the principles of plain language 
includes consideration of the following questions:
     Have we organized the material to suit the public's needs?
     Are the requirements in the rule clearly stated?
     Does the rule contain technical language or jargon that 
isn't clear?
     Would a different format (grouping and order of sections, 
use of headings, paragraphing) make the rule easier to understand?
     Would more (but shorter) sections be better?
     Could we improve clarity by adding tables, lists, or 
diagrams?
     What else could we do to make the rule easier to 
understand?
    If you have any responses to these questions, please write to us 
with your views.

XII. Public Participation

How long do I have to submit comments?

    Please see the DATES section at the beginning of this document.

How do I prepare and submit comments?

     Your comments must be written in English.
     To ensure that your comments are correctly filed in the 
Docket, please include the Docket Number shown at the beginning of this 
document in your comments.
     Your comments must not be more than 15 pages long. (49 CFR 
553.21). We established this limit to encourage you to write your 
primary comments in a concise fashion. However, you may attach 
necessary additional documents to your comments. There is no limit on 
the length of the attachments.
     If you are submitting comments electronically as a PDF 
(Adobe) File, NHTSA asks that the documents be submitted using the 
Optical Character Recognition (OCR) process, thus allowing NHTSA to 
search and copy certain portions of your submissions. Comments may be 
submitted to the docket electronically by logging onto the Docket 
Management System website at http://www.regulations.gov. Follow the 
online instructions for submitting comments.
     You may also submit two copies of your comments, including 
the attachments, to Docket Management at the address given above under 
ADDRESSES.
    Please note that pursuant to the Data Quality Act, in order for 
substantive data to be relied upon and used by the agency, it must meet 
the information quality standards set forth in the OMB and DOT Data 
Quality Act guidelines. Accordingly, we encourage you to consult the 
guidelines in preparing your comments. OMB's guidelines may be accessed 
at http://www.whitehouse.gov/omb/information-regulatory-affairs/information-policy/. DOT's guidelines may be accessed at http://www.transportation.gov/dot-information-dissemination-quality-guidelines.

How can I be sure that my comments were received?

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

How do I submit confidential business information?

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

Will the agency consider late comments?

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

How can I read the comments submitted by other people?

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

XIII. Appendices to the Preamble

Appendix A: Description of Technologies

    For the convenience of readers, this section describes various 
technologies of an AEB system. An AEB system employs multiple sensor 
technologies and sub-systems that work together to sense a crash 
imminent scenario and, where applicable, automatically apply the 
vehicle brakes to avoid or mitigate a crash. Current systems utilize 
radar- and camera-based sensors, and the agency is aware of emerging 
technologies such as lidar and infrared sensors. AEB builds upon 
electronic stability control (ESC) technology joined with a perception 
system, and ESC itself is an extension of antilock braking system (ABS) 
technologies. It also builds upon older forward collision warning-only 
(FCW-only) systems.

Radar-Based Sensors

    At its simplest form, radar is a time-of-flight sensor that 
measures the time between when a radio wave is transmitted, and its 
reflection is recorded. This time-of-flight is then used to calculate 
the distance to the object that caused the reflection. More information 
about the reflecting object,

[[Page 38718]]

such as speed, can be determined by comparing the output signal to the 
input signal. Typical automotive applications use a type of radar 
called Frequency Modulated Continuous Wave radar. This radar system 
sends out a radio pulse where the pulse frequency rises through the 
duration of the pulse. This pulse is reflected off the object and the 
radar sensor compares the reflected signal to the original pulse to 
determine the range and relative speed.
    Radar sensors are widely used in AEB applications, for many 
reasons. These sensors can have a wide range of applicability, with 
automotive grade radar sensing ranges on the order of 1 meter (3 ft) up 
to over 200 meters (656 ft). Radar sensors are also relatively 
unaffected by time of day, precipitation, fog, and many other adverse 
weather conditions. Automotive radar systems typically operate on 
millimeter wave lengths, easily reflecting off even the smallest 
metallic surfaces found on vehicles. Radio waves tend to penetrate soft 
materials, such as rubber and plastic, allowing these sensors to be 
mounted in the front ends of vehicles behind protective and visually 
appealing grilles and bumper fascia.
    Radar-based sensors have limitations that impact their 
effectiveness. Radar is a line-of-sight sensor, in that it only 
operates in the direction the receiving antenna is pointed and 
therefore has a limited angular view. Also, while radar is excellent at 
identifying radar-reflective objects, the nature of the radar 
reflection makes classification of those objects difficult. In 
addition, objects that do not reflect radio waves easily, such as 
rubber, plastic, humans, and other soft objects, are difficult for 
radar-based sensors to detect. Lastly, because forward facing radar 
sensors are usually mounted inside the front end of equipped vehicles, 
damage caused from front-end collisions can lead to alignment issues 
and reduced effectiveness.

Camera Sensors

    Cameras are passive sensors that record optical data using digital 
imaging chips, which are then processed to allow for object detection 
and classification. They are an important part of most automotive AEB 
systems, and one or more cameras are typically mounted behind the front 
windshield, often high up near the rearview mirror. This provides a 
good view of the road, and the windshield wipers can provide a way to 
clear debris, dirt, and other contaminates from the windshield in front 
of the sensor.
    Camera-based imaging systems are one of the few sensor types that 
can determine both color and contrast information. This makes them able 
to recognize and classify objects such as road signs, other vehicles, 
and pedestrians, much in the same way the human eye does. In addition, 
systems that utilize two or more cameras can see stereoscopically, 
allowing the processing system to determine range information along 
with detection and classification.
    Like all sensor systems, camera-based sensors have their benefits 
and limitations. Monocular camera systems lack depth perception and are 
poor at determining range, and even stereoscopic camera systems are not 
ideal for determining speed. Because cameras rely on the visible 
spectrum of light, conditions that make it difficult to see, such as 
rain, snow, sleet, fog, and even dark unlit areas, decrease the 
effectiveness of perception checks of these systems. It is also 
possible for the imaging sensor to saturate when exposed to excessive 
light, such as driving towards the sun. For these reasons, camera 
sensors are often used in conjunction with other sensors like radar.

Thermal Imaging Systems

    While rare in the current generation of AEB systems, suppliers of 
AEB technologies are looking at advanced sensor technologies to augment 
the limitations of camera/radar systems. Thermal imaging systems are 
one such advanced sensor. Very similar to cameras, thermal imaging 
systems are optical sensors that record visual information. The 
difference is that, where cameras rely on the visible spectrum of 
light, thermal imaging systems rely on infrared radiation, also known 
as thermal radiation.
    Infrared radiation is the part of the electromagnetic spectrum 
between visible light and microwave radiation. Typically, the 
wavelengths range from 750 nm up to 1 mm. This spectrum also 
corresponds to the energy output by warm bodies, making these sensors 
ideal for use in dark areas where traditional cameras may have 
difficulties. Thermal imaging systems can be particularly useful for 
darkness detection of pedestrians. They can also have an active 
component, either a blanket infrared flood light or an infrared laser 
system, to augment the passive collection of a camera.
    These systems, however, also have limitations. They may not be able 
to differentiate between multiple hot bodies, and in the presence of 
thermal insulation, such as a jacket or cold weather clothing, warm 
bodies can appear cold and difficult to differentiate from the 
background. Reflectivity of the detected object as well as the ambient 
environment can affect the performance of these systems.

Lidar

    Lidar, or Light Detection and Ranging is a laser-based time-of-
flight sensor that uses pulses of visual light to determine distances 
between the sensor and an object. Much like radar, by calculating the 
amount of time between the transmission and reception of a pulse of 
light, a lidar system can determine the distance to the object. These 
sensors are one of the primary sensors in prototype automated driving 
systems under development for future AEB systems.\262\
---------------------------------------------------------------------------

    \262\ SAE J3016, ``Taxonomy and Definitions for Terms Related to 
Driving Automation Systems for On-Road Motor Vehicles,'' APR2021, 
defines an automated driving system as the hardware and software 
that are collectively capable of performing the entire dynamic 
driving task on a sustained basis, regardless of whether it is 
limited to a specific operational design domain.
---------------------------------------------------------------------------

    Because a lidar system uses lasers for range-finding, it can infer 
exact measurements of most objects surrounding a vehicle, including 
other vehicles and pedestrians. Because of how accurately lidar can 
measure distances and speeds, it is very good at determining the 
differences between cars, pedestrians, cyclists, light posts, road 
signs, and many other obstacles in the path of a vehicle. With proper 
control software, a lidar sensor can detect things like lane 
boundaries.
    Limitations of lidar tend to be similar to those of both camera 
systems and radar systems. lidar is an active system, so it is 
unaffected by dark lighting conditions, but it can be severely degraded 
by rain, sleet, fog, or snow. It is a line-of-sight sensor and cannot 
see through certain objects in the way that radar can. Its maximum 
effective range is often limited by surface reflectivity, illumination 
saturation (driving towards the sun or other bright light), and 
environmental attenuation, such as hazy conditions or heat shimmer. 
Other limiting factors are the large computational processing needs to 
adequately utilize the lidar sensor, and its currently high costs.

Electronically Modulated Braking Systems

    Automatic actuation of the vehicle brakes requires more than just 
systems to sense when a collision is imminent. Regardless of how good a 
sensing system is, hardware is needed to physically apply the brakes 
without relying on the driver to modulate the brake pedal. The 
automatic braking system relies on two foundational

[[Page 38719]]

braking technologies, antilock braking systems and electronic stability 
control.
    Antilock brakes are a foundational braking technology that 
automatically controls the degree of wheel slip during braking to 
prevent wheel lock and minimize skidding, by sensing the rate of 
angular rotation of the wheels and modulating the braking force at the 
wheels to keep the wheels from slipping. Modern ABS systems have wheel 
speed sensors and independent brake modulation at each wheel and can 
increase and decrease braking pressures as needed.
    ESC builds upon the antilock brakes with the addition of at least 
two sensors, a steering wheel angle sensor and an inertial measurement 
unit. These sensors allow the ESC controller to determine the intended 
steering direction (from the steering wheel angle sensor), compare it 
to the actual vehicle direction, and then modulate braking forces at 
each wheel, without the driver applying input to the brake pedal, to 
induce a counter yaw when the vehicle starts to lose lateral stability.
    AEB uses the hardware needed for ESC and automatically applies the 
brakes to avoid certain scenarios where a crash with a vehicle or 
pedestrian is imminent.

Forward Collision Warning

    Using the sensors described above, coupled with an alert mechanism 
and perception calculations, a FCW system is able to monitor a 
vehicle's speed, the speed of the vehicle in front of it, and the 
distance between the two vehicles. If the FCW system determines that 
the distance from the driver's vehicle to the vehicle in front of it is 
too short and the closing velocity between the two vehicles is too 
high, the system warns the driver of an impending rear-end collision.
    Typically, FCW systems are comprised of two components: a sensing 
system, which can detect a vehicle in front of the driver's vehicle, 
and a warning system, which alerts the driver to a potential crash 
threat. The sensing portion of the system may consist of forward-
looking radar, camera systems, lidar, or a combination of these. 
Warning systems in use today provide drivers with a visual display, 
such as an illuminated telltale on the instrument panel, an auditory 
signal (e.g., beeping tone or chime), and/or a haptic signal that 
provides tactile feedback to the driver (e.g., rapid vibrations of the 
seat pan or steering wheel or a momentary brake pulse) to alert the 
driver to an impending crash so that the driver may manually intervene 
(e.g., apply the vehicle's brakes or make an evasive steering maneuver) 
to avoid or mitigate the crash.
    FCW systems alone are designed to warn the driver, but do not 
provide automatic braking of the vehicle (some FCW systems use haptic 
brake pulses to alert the driver of a crash-imminent driving situation, 
but they are not intended to effectively slow the vehicle). Since the 
first introduction of FCW systems, the technology has advanced so that 
it is now possible to couple those sensors, software, and alerts with 
the vehicle's service brake system to provide additional functionality 
covering a broader portion of the safety problem.
    From a functional perspective, research suggests that active 
braking systems, such as AEB, provide greater safety benefits than 
warning systems, such as FCW systems. However, 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 and high consumer acceptance. FCW can now be 
considered a component of lead vehicle AEB. As such, this NPRM 
integrates FCW directly into the performance requirements for AEB--Lead 
Vehicle. This integration would also enable the agency to assess 
vehicles' compliance with the proposed FCW and AEB requirements at the 
same time in a single test.

Automatic Emergency Braking--Lead Vehicle

    Unlike systems that only alert, AEB systems (systems that 
automatically apply the brakes), are designed to actively help drivers 
avoid or mitigate the severity of rear-end crashes. AEB--Lead Vehicle 
has been previously broken down into two primary functions, crash 
imminent braking and dynamic brake support. CIB systems provide 
automatic braking when forward-looking sensors indicate that a crash is 
imminent and the driver has not applied the brakes, whereas DBS systems 
use the same forward-looking sensors, but provide supplemental braking 
after the driver applies the brakes when sensors determine that driver-
applied braking is insufficient to avoid an imminent rear-end crash. 
This NPRM does not split the terminology of these functionalities and 
instead discusses them together as ``AEB.'' In some crash situations, 
AEB functions independently of the driver's use of the brake pedal 
(CIB), while in other situations, the vehicle uses the driver's pedal 
input to better evaluate the situation and avoid the crash (DBS). This 
proposal considers each function necessary to address the safety need 
and presents a performance-based regulatory approach that can permit 
the detailed application of each function to be based on the specific 
vehicle application and the manufacturer's approach to meeting the 
standard.
    In response to an FCW or a driver noticing an imminent crash 
scenario, a driver may initiate braking to avoid a rear-end crash. In 
situations where the driver's braking is insufficient to prevent a 
collision, the AEB system can automatically supplement the driver's 
braking action to prevent or mitigate the crash. Similar to FCW 
systems, AEB systems employ forward-looking sensors such as radar, 
cameras, infrared, and/or lidar sensors to detect vehicles in the path 
directly ahead and monitor the subject vehicle's operating conditions 
such as speed or brake application. However, AEB systems can also 
actively supplement braking to assist the driver, whereas FCW systems 
serve only to warn the driver of a potential crash threat.
    If a driver does not take action to apply the brakes when a rear-
end crash is imminent, AEB systems utilize the same types of forward-
looking sensors to apply the vehicle's brakes automatically to slow or 
stop the vehicle. The amount of braking applied varies by manufacturer, 
and several systems are designed to achieve maximum vehicle 
deceleration just prior to impact. In reviewing model year 2017-2019 
NCAP crash imminent braking test data, NHTSA observed a deceleration 
range of 0.31 to 1.27 g. This NPRM does not directly require a 
particular deceleration capability but specifies situations in which 
crash avoidance must be achieved. Avoidance may be produced by the 
automatic application of the subject vehicle brakes or by automatically 
supplementing the deceleration achieved by driver's braking action in 
the case where the subject vehicle brakes are manually applied.

Pedestrian Automatic Emergency Braking

    PAEB systems function like lead vehicle AEB systems, but detect 
pedestrians instead of leading vehicles. PAEB uses information from 
forward-looking sensors to actively and automatically apply the 
vehicle's brakes when a pedestrian is in front of the vehicle and the 
driver has not acted to avoid the impending impact. Similar to lead 
vehicle AEB, PAEB systems typically use cameras to determine whether a 
pedestrian is in imminent danger of being struck by the vehicle, but 
some systems may use a

[[Page 38720]]

combination of cameras, radar, lidar, and infrared sensors.
    A camera's field of view plays a key role in the type of pedestrian 
crashes that a PAEB system can assist in avoiding. Cameras used for 
PAEB can provide the information required by the system to provide 
crash protection in situations where the pedestrian is either directly 
in the path of a vehicle or is entering the path of the vehicle while 
the vehicle is moving straight ahead.
    Sensor performance may be limited by the availability of 
environmental lighting. The cameras used in PAEB systems rely on 
reflected light in the same way as a human eye. As such, the vehicle's 
integration of headlighting systems along with the tuning of camera 
exposure rates and sensor light sensitivities are important 
considerations in producing an PAEB system that assists in avoiding 
pedestrian crashes that happen at night. The permeance limits proposed 
in this NPRM can be achieved with radar and camera system technologies.

Appendix B: International Activities

International AEB Testing Standards

    NHTSA has considered other vehicle testing organizations' AEB test 
procedures as part of the development of this proposal. The ISO has 
published Standard 22733-1, ``Road vehicles--Test method to evaluate 
the performance of autonomous emergency braking systems.'' This ISO 
standard does not set minimum performance requirements for lead vehicle 
AEB systems or any pass/fail conditions. Instead, the standard sets 
forth a test procedure using progressively increasing speeds at which a 
vehicle equipped with lead vehicle AEB approaches a stationary or 
moving surrogate vehicle until it makes contact.
    The surrogate vehicle specified is the vehicle target defined in 
ISO 19206- 3:2021, ``Road vehicles--Test devices for target vehicles, 
vulnerable road users and other objects, for assessment of active 
safety functions--Part 3: requirements for passenger vehicle 3D 
targets.''
    ISO is developing but has not published Standard 22733-2 describing 
tests for PAEB systems. SAE International has published recommended 
practice J3087, ``Automatic emergency braking (AEB) system performance 
testing,'' defining the conditions for testing AEB and FCW systems. 
This standard defines test conditions, test targets, test scenarios, 
and measurement methods, but, like ISO 22733-1, does not provide 
performance criteria. Unlike ISO 22733-1, SAE J3087 does not require 
specific speed ranges for test execution. Test scenarios are employed 
where the lead surrogate vehicle is stopped, moving at a constant 
slower speed, or decelerating, broadly similar to that proposed in this 
NPRM. SAE International Standard J3116, ``Active Safety Pedestrian Test 
Mannequin Recommendation,'' provides recommendations for the 
characteristics of a surrogate that could be used in testing of active 
pedestrian safety systems, but there is no SAE International standard 
defining test procedures for PAEB systems.

International AEB Regulation

    The United Nations (UN) Economic Commission for Europe (ECE) 
Regulation No. 152 ``Uniform provisions concerning the approval of 
motor vehicles with regard to the Advanced Emergency Braking System 
(AEBS) for M1 and N1 vehicles,'' \263\ provides definitions and 
standards for AEB Systems for signatory nations to the ``1958 
Agreement.'' \264\ Some signatories mandate the regulation and others 
accept it as ``if-fitted.'' ECE Regulation No. 152 describes the timing 
of warnings, mode of warnings, required minimum deceleration, and 
allowable impact speeds for AEB tests for both stationary lead 
surrogate vehicles and lead surrogate vehicles moving at 20 km/h. Each 
test run is conducted ``in absence of driver's input,'' (i.e., testing 
CIB but not DBS). A ``false reaction test'' is also specified, where a 
vehicle must pass between two parked vehicles without issuing a warning 
or applying the brakes. AEB systems are required to operate between 10 
km/h and 60 km/h, and cannot be deactivated at speeds above 10 km/h.
---------------------------------------------------------------------------

    \263\ As defined in the Addenda to the 1958 Agreement, inclusive 
of Amendments published Dec 21, 2021. https://unece.org/transport/vehicle-regulations-wp29/standards/addenda-1958-agreement-regulations-141-160.
    \264\ United Nations Economic Commission for Europe. Agreement 
concerning the Adoption of Harmonized Technical United Nations 
Regulations for Wheeled Vehicles, Equipment and Parts which can be 
Fitted and/or be Used on Wheeled Vehicles and the Conditions for 
Reciprocal Recognition of Approvals Granted on the Basis of these 
United Nations Regulations (Revision 3). (Original: 1958; Current, 
as amended: 20 Oct. 2017). https://unece.org/trans/main/wp29/wp29regs. The U.S. is not a signatory to the 1958 Agreement.
---------------------------------------------------------------------------

    ECE Regulation No. 152 also describes requirements and test 
procedures for PAEB systems, including specification of minimum 
daylight lighting conditions (which match this NPRM) and surrogates. 
Test scenarios for PAEB systems include a test for a crossing test 
mannequin, and a false positive test where a test mannequin is parallel 
with and outside of the subject vehicle's path, and the vehicle must 
not issue a warning or provide braking. Further specifications test for 
electrical failure and compliance with deactivation requirements (if 
equipped). A ``car to bicycle'' test and required standards are also 
specified, which our proposed regulation does not include.
    For both the ``car to car'' and ``car to pedestrian'' tests, 
performance requirements are differentiated for M1 passenger vehicles 
and N1 goods carrying vehicles at different loaded masses and at 
different speeds; for some speed and weight combinations, collision 
avoidance is required. Starting at 38 km/h (24 mph), the standard 
specifies a maximum allowable impact speed; in contrast, our proposed 
regulation requires collision avoidance at up to 80 km/h (50 mph) 
without driver intervention. Up to 10 percent of test runs in any 
category can be failed and the system would still be given 
certification.

International AEB Consumer Testing

    Internationally, several organizations also test vehicles' lead 
vehicle AEB systems to provide safety information to consumers. Euro 
NCAP, Australasian NCAP, and Korean NCAP each test lead vehicle AEB 
systems using scenarios similar to NHTSA's NCAP, where the lead vehicle 
test device is stationary, moving more slowly, or decelerating. ASEAN 
NCAP, China NCAP, and Japan NCAP each test vehicle lead vehicle AEB 
systems using stationary or slower-moving lead vehicle scenarios. Latin 
NCAP tests lead vehicle AEB systems using slower moving or decelerating 
lead vehicle scenarios. As discussed further in this notice, NHTSA will 
require collision avoidance over a range of subject vehicle test 
speeds; in contrast, Euro NCAP, Australasian NCAP, Korean NCAP, Chinese 
NCAP, and Japan NCAP each test AEB starting at 10 km/h and increase the 
speed during progressive test runs until the vehicle strikes the 
surrogate. There are no false positive tests, and points are awarded 
based on the speed at which the vehicle surrogate was struck.
    Euro NCAP, China NCAP, Japan NCAP, and Korean NCAP each test PAEB 
systems in crossing path scenarios with a test mannequin. Euro NCAP and 
China NCAP further test PAEB systems for pedestrians walking parallel 
along the subject vehicle's forward path. Euro NCAP also tests PAEB 
systems for vehicles turning into a crossing test mannequin's path at 
an intersection. A variety of lighting conditions are used depending 
upon the scenario tested, with each organization conducting PAEB tests 
using daylight

[[Page 38721]]

conditions, darkness conditions with streetlights, or darkness 
conditions without streetlights for at least one of their tests. There 
are no false positive tests, and for each test, the testing programs 
award points or provide a rating based on each vehicle's AEB 
performance.
    Euro NCAP specifies the test mannequin in its ``Articulated 
Pedestrian Target Specification Document,'' \265\ which sets 
specifications for size, color, motion patterns, and detectability by 
vehicle sensors. China NCAP, Japan NCAP, and Korean NCAP use the same 
specifications, either by reference or substantially similar 
translation. These specifications are used by the test mannequin 
supplier to IIHS and NHTSA research.
---------------------------------------------------------------------------

    \265\ European Automobile Manufacturers' Association (ACEA), 
February 2016, ``Articulated Pedestrian Target Specification 
Document,'' Version 1.0. https://www.acea.auto/publication/articulated-pedestrian-target-acea-specifications/.
---------------------------------------------------------------------------

List of Subjects

49 CFR Part 571

    Imports, Incorporation by Reference, Motor vehicle safety, Motor 
vehicles, and Tires.

49 CFR Part 596

    Automatic emergency braking, Incorporation by Reference, Motor 
vehicle safety, Test devices.

    In consideration of the foregoing, NHTSA proposes to amend 49 CFR 
chapter V as follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

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

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

0
2. Amend Sec.  571.5 by:
0
a. Revising paragraph (d)(34);
0
b. Redesignating paragraphs (l)(49) and (50) as paragraphs (l)(50) and 
(51), respectively; and
0
c. Adding new paragraph (l)(49).
    The revisions and additions read as follows:


Sec.  571.5  Matter incorporated by reference.

* * * * *
    (d) * * *
    (34) ASTM E1337-19, ``Standard Test Method for Determining 
Longitudinal Peak Braking Coefficient (PBC) of Paved Surfaces Using 
Standard Reference Test Tire,'' approved December 1, 2019, into 
Sec. Sec.  571.105; 571.121; 571.122; 571.126; 571.127; 571.135; 
571.136; 571.500.
* * * * *
    (l) * * *
    (49) SAE J2400, ``Human Factors in Forward Collision Warning 
System: Operating Characteristics and User Interface Requirements,'' 
August 2003 into Sec.  571.127.
* * * * *
0
3. Add Sec.  571.127 to read as follows:


Sec.  571.127  Standard No. 127; Automatic emergency braking systems 
for light vehicles.

    S1. Scope. This standard establishes performance requirements for 
automatic emergency braking (AEB) systems for light vehicles.
    S2. Purpose. The purpose of this standard is to reduce the number 
of deaths and injuries that result from crashes in which drivers do not 
apply the brakes or fail to apply sufficient braking power to avoid or 
mitigate a crash.
    S3. Application. This standard applies to passenger cars and to 
multipurpose passenger vehicles, trucks, and buses with a gross vehicle 
weight rating of 4,536 kilograms (10,000 pounds) or less.
    S4. Definitions.
    Adaptive cruise control system is an automatic speed control system 
that allows the equipped vehicle to follow a lead vehicle at a pre-
selected gap by controlling the engine, power train, and service 
brakes.
    Ambient illumination is the illumination as measured at the test 
surface, not including any illumination provided by the subject 
vehicle.
    Automatic emergency braking (AEB) system is a system that detects 
an imminent collision with vehicles, objects, and road users in or near 
the path of a vehicle and automatically controls the vehicle's service 
brakes to avoid or mitigate the collision.
    Brake pedal application onset is when 11 N of force has been 
applied to the brake pedal.
    Forward collision warning is an auditory and visual warning 
provided to the vehicle operator by the AEB system that is designed to 
induce immediate forward crash avoidance response by the vehicle 
operator.
    Forward collision warning onset is the first moment in time when a 
forward collision warning is provided.
    Headway is the distance between the lead vehicle's rearmost plane 
normal to its centerline and the subject vehicle's frontmost plane 
normal to its centerline.
    Lead vehicle is a vehicle test device facing the same direction and 
preceding a subject vehicle within the same travel lane.
    Lead vehicle braking onset is the point at which the lead vehicle 
achieves a deceleration of 0.05 g due to brake application.
    Pedestrian test mannequin is a device used during AEB testing, when 
approaching pedestrians, meeting the specifications of subpart B of 49 
CFR part 596.
    Small-volume manufacturer means an original vehicle manufacturer 
that produces or assembles fewer than 5,000 vehicles annually for sale 
in the United States.
    Steel trench plate is a rectangular steel plate often used in road 
construction to temporarily cover sections of pavement unsafe to drive 
over directly.
    Subject vehicle is the vehicle under examination for compliance 
with this standard.
    Travel path is the path projected onto the road surface of a point 
located at the intersection of the subject vehicle's frontmost vertical 
plane and longitudinal vertical center plane, as the subject vehicle 
travels forward.
    Vehicle Test Device is a device meeting the specifications set 
forth in subpart C of 49 CFR part 596.
    S5. Requirements.
    (a) Except as provided in paragraphs (b) and (c) of this section 
S5, vehicles manufactured on or after [the first September 1 that is 
three years after publication of a final rule] must meet the 
requirements of this standard.
    (b) The following lower-speed performance test requirements apply 
to vehicles manufactured on or after [the first September 1 that is 
three years after date of publication of a final rule] and before [the 
first September 1 that is four years after the date of publication of a 
final rule].
    (1) For testing in the darkness condition using lower beam 
headlamps with an intended overlap of 50 percent, the subject vehicle 
test speed in S8.3.1(g) is any speed between 10 km/h and 40 km/h.
    (2) For testing in the darkness condition using lower beam 
headlamps, the subject vehicle test speed in S8.4.1(e) is any speed 
between 10 km/h and 50 km/h.
    (3) For testing in the darkness condition, the subject vehicle test 
speed in S8.5.1(f) is any speed between 10 km/h and 60 km/h.
    (c) The requirements of paragraphs (a) and (b) of this section S5 
do not apply to small-volume manufacturers, final-stage manufacturers 
and alterers until one year after the dates specified in those 
paragraphs.
    S5.1. Requirements when approaching a lead vehicle.
    S5.1.1. Forward Collision Warning. A vehicle is required to have a 
forward

[[Page 38722]]

collision warning system, as defined in S4 of this section, that 
provides an auditory and visual signal to the driver of an impending 
collision with a lead vehicle when traveling at any forward speed 
greater than 10 km/h (6.2 mph). The auditory signal must have a high 
fundamental frequency of at least 800 Hz, a duty cycle of 0.25-0.95, 
and tempo in the range of 6-12 pulses per second. The visual signal 
must be located according to SAE J2400 (incorporated by reference see 
Sec.  571.5), paragraph 4.1.14 and must include the symbol in the 
bottom right of paragraph 4.1.16. Line of sight is based on the 
forward-looking eye midpoint (Mf) as described in S14.1.5. 
of Sec.  571.111 of this part. The symbol must be red in color and 
steady-burning.
    S5.1.2. Automatic Emergency Braking. A vehicle is required to have 
an automatic emergency braking system, as defined in S4 of this 
section, that applies the service brakes automatically when a collision 
with a lead vehicle is imminent. The system must operate when the 
vehicle is traveling at any forward speed greater than 10 km/h (6.2 
mph).
    S5.1.3. Performance Test Requirements. The vehicle must provide a 
forward collision warning and subsequently apply the service brakes 
automatically when a collision with a lead vehicle is imminent such 
that the subject vehicle does not collide with the lead vehicle when 
tested using the procedures in S7 under the conditions specified in S6. 
The forward collision warning is not required if adaptive cruise 
control is engaged.
    S5.2. Requirements when approaching pedestrians.
    S5.2.1. Forward Collision Warning. A vehicle is required to have a 
forward collision warning system, as defined in S4 of this section, 
that provides an auditory and visual signal to the driver of an 
impending collision with a pedestrian. The auditory signal must have a 
high fundamental frequency of at least 800 Hz, a duty cycle of 0.25-
0.95, and tempo in the range of 6-12 pulses per second. The visual 
signal must be located according to SAE J2400, (incorporated by 
reference see Sec.  571.5), paragraph 4.1.14 and must include the crash 
icon in the bottom right of paragraph 4.1.16. Line of sight is based on 
the forward-looking eye midpoint (Mf) as described in 
S14.1.5. of Sec.  571.111. The symbol must be red in color and steading 
burning. The system must operate at any forward speed greater than 10 
km/h (6.2 mph).
    S5.2.2. Automatic Emergency Braking. A vehicle is required to have 
an automatic emergency braking system, as defined in S4 of this 
section, that applies the service brakes automatically when a collision 
with a pedestrian is imminent when the vehicle is traveling at any 
forward speed greater than 10 km/h (6.2 mph).
    S5.2.3. Performance Test Requirements. The vehicle must 
automatically apply the brakes and alert the vehicle operator such that 
the subject vehicle does not collide with the pedestrian test mannequin 
when tested using the procedures in S8 under the conditions specified 
in S6.
    S5.3. False Activation. The vehicle must not automatically apply 
braking that results in peak additional deceleration that exceeds what 
manual braking would produce by 0.25g or greater, when tested using the 
procedures in S9 under the conditions specified in S6.
    S5.4. Malfunction Detection. The system must continuously detect 
system malfunctions, including malfunctions caused solely by sensor 
obstructions. If the system detects a malfunction that prevents the 
system from meeting the requirements specified in S5.1, S5.2, or S5.3, 
the system must provide the vehicle operator with a telltale 
notification that the malfunction exists.
    S6. Test Conditions.
    S6.1. Environmental conditions.
    S6.1.1. Temperature. The ambient temperature is any temperature 
between 0 [deg]C and 40 [deg]C.
    S6.1.2. Wind. The maximum wind speed is no greater than 10 m/s (22 
mph) during lead vehicle avoidance tests and 6.7 m/s (15 mph) during 
pedestrian avoidance tests.
    S6.1.3. Ambient Lighting.
    (a) Daylight testing.
    (1) The ambient illumination on the test surface is any level at or 
above 2,000 lux.
    (2) Testing is not performed while driving toward or away from the 
sun such that the horizontal angle between the sun and a vertical plane 
containing the centerline of the subject vehicle is less than 25 
degrees and the solar elevation angle is less than 15 degrees.
    (b) Dark testing.
    (1) The ambient illumination on the test surface is any level at or 
below 0.2 lux.
    (2) Testing is performed under any lunar phase.
    (3) Testing is not performed while driving toward the moon such 
that the horizontal angle between the moon and a vertical plane 
containing the centerline of the subject vehicle is less than 25 
degrees and the lunar elevation angle is less than 15 degrees.
    S6.1.4. Precipitation. Testing is not conducted during periods of 
precipitation or when visibility is affected by fog, smoke, ash, or 
other particulate.
    S6.2. Road conditions.
    S6.2.1. Test Track Surface and Construction. The tests are 
conducted on a dry, uniform, solid-paved surface. Surfaces with debris, 
irregularities, or undulations, such as loose pavement, large cracks, 
or dips are not used.
    S6.2.2. Surface Friction. The road test surface produces a peak 
friction coefficient (PFC) of 1.02 when measured using an American 
Society for Testing and Materials (ASTM) F2493 standard reference test 
tire, in accordance with ASTM E1337-19 (incorporated by reference, see 
Sec.  571.5), at a speed of 64 km/h (40 mph), without water delivery.
    S6.2.3. Slope. The test surface has any consistent slope between 0 
percent and 1 percent.
    S6.2.4. Markings. The road surface within 2 m of the intended 
travel path is marked with zero, one, or two lines of any configuration 
or color. If one line is used, it is straight. If two lines are used, 
they are straight, parallel to each other, and at any distance from 2.7 
m to 4.5 m apart.
    S6.2.5. Obstructions. Testing is conducted such that the vehicle 
does not travel beneath any overhead structures, including but not 
limited to overhead signs, bridges, or gantries. No vehicles, 
obstructions, or stationary objects are within 7.4 m of either side of 
the intended travel path except as specified.
    S6.3. Subject vehicle conditions.
    S6.3.1. Malfunction notification. Testing is not conducted while 
the AEB malfunction telltale specified in S5.4 is illuminated.
    S6.3.2. Sensor obstruction. All sensors used by the system and any 
part of the vehicle immediately ahead of the sensors, such as plastic 
trim, the windshield, etc., are free of debris or obstructions.
    S6.3.3. Tires. The vehicle is equipped with the original tires 
present at the time of initial sale. The tires are inflated to the 
vehicle manufacturer's recommended cold tire inflation pressure(s) 
specified on the vehicle's placard or the tire inflation pressure 
label.
    S6.3.4. Brake burnish.
    (a) Vehicles subject to Sec.  571.105 are burnished in accordance 
with S7.4 of that section.
    (b) Vehicles subject to Sec.  571.135 are burnished in accordance 
with S7.1 of that section.
    S6.3.5. Brake temperature. The average temperature of the service 
brakes on the hottest axle of the vehicle during testing, measured 
according to

[[Page 38723]]

S6.4.1 of Sec.  571.135, is between 65 [deg]C and 100.[deg]C prior to 
braking.
    S6.3.6. Fluids. All non-consumable fluids for the vehicle are at 
100 percent capacity. All consumable fluids are at any level from 5 to 
100 percent capacity.
    S6.3.7. Propulsion battery charge. The propulsion batteries are 
charged at any level from 5 to 100 percent capacity.
    S6.3.8. Cruise control. Cruise control, including adaptive cruise 
control, is configured under any available setting.
    S6.3.9. Adjustable forward collision warning. Forward collision 
warning is configured in any operator-configurable setting.
    S6.3.10. Engine braking. A vehicle equipped with an engine braking 
system that is engaged and disengaged by the operator is tested with 
the system in any selectable configuration.
    S6.3.11. Regenerative braking. Regenerative braking is configured 
under any available setting.
    S6.3.12. Headlamps.
    (a) Daylight testing is conducted with the headlamp control in any 
selectable position.
    (b) Darkness testing is conducted with the vehicle's lower beams or 
upper beams active.
    (c) Prior to performing darkness testing, headlamps are aimed 
according to the vehicle manufacturer's instructions. The weight of the 
loaded vehicle at the time of headlamp aiming is within 10 kg of the 
weight of the loaded vehicle during testing.
    S6.3.13. Subject vehicle loading. The vehicle load, which is the 
sum of any vehicle occupants and any test equipment and 
instrumentation, does not exceed 277 kg. The load does not cause the 
vehicle to exceed its GVWR or any axle to exceed its GAWR.
    S6.3.14. AEB system initialization. The vehicle is driven at a 
speed of 10 km/h or higher for at least one minute prior to testing, 
and subsequently the starting system is not cycled off prior to 
testing.
    S6.4. Equipment and Test Devices.
    S6.4.1. The vehicle test device is specified in 49 CFR part 596 
subpart C. Local fluttering of the lead vehicle's external surfaces 
does not exceed 10 mm perpendicularly from the reference surface, and 
distortion of the lead vehicle's overall shape does not exceed 25 mm in 
any direction.
    S6.4.2. Adult Pedestrian Test Mannequin is specified in 49 CFR part 
596 subpart B.
    S6.4.3. Child Pedestrian Test Mannequin is specified in 49 CFR part 
596 subpart B.
    S6.4.4. The steel trench plate used for the false activation test 
has the dimensions 2.4 m x 3.7 m x 25 mm and is made of ASTM A36 steel. 
Any metallic fasteners used to secure the steel trench plate are flush 
with the top surface of the steel trench plate.
    S7. Testing when approaching a lead vehicle.
    S7.1. Setup.
    (a) The testing area is set up in accordance with Figure 2.
    (b) Testing is conducted during daylight.
    (c) For reference, Table 1 to S7.1 specifies the subject vehicle 
speed (VSV), lead vehicle speed (VLV), headway, 
and lead vehicle deceleration for each test that may be conducted.
    (d) The intended travel path of the vehicle is a straight line 
toward the lead vehicle from the location corresponding to a headway of 
L0.
    (e) If the road surface is marked with a single or double lane 
line, the intended travel path is parallel to and 1.8 m from the inside 
of the closest line. If the road surface is marked with two lane lines 
bordering the lane, the intended travel path is centered between the 
two lines.
    (f) For each test run conducted, the subject vehicle speed 
(VSV), lead vehicle speed (VLV), headway, and 
lead vehicle deceleration will be selected from the ranges specified.

                                            Table 1 to S7.1--Test Parameters When Approaching a Lead Vehicle
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                   Speed (km/hr)
                                     -----------------------------------------       Headway (m)       Lead vehicle decel (g)   Manual brake application
                                                VSV                  VLV
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stopped Lead Vehicle................  Any 10-80..............               0  ......................  ......................  No.
                                      Any 70-100.............               0  ......................  ......................  Yes.
Slower Lead Vehicle.................  Any 40-80..............              20  ......................  ......................  No.
                                      Any 70-100.............              20  ......................  ......................  Yes.
Decelerating Lead Vehicle...........  50.....................              50  Any 12-40.............  Any 0.3-0.5...........  No.
                                      50.....................              50  Any 12-40.............  Any 0.3-0.5...........  Yes.
                                      80.....................              80  Any 12-40.............  Any 0.3-0.5...........  No.
                                      80.....................              80  Any 12-40.............  Any 0.3-0.5...........  Yes.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    S7.2. Headway calculation. For each test run conducted under S7.3 
and S7.4, the headway (L0), in meters, providing 5 seconds 
time to collision (TTC) is calculated. L0 is determined with 
the following equation where VSV is the speed of the subject vehicle in 
m/s and VLV is the speed of the lead vehicle in m/s:

L0 = TTC0 x (VSV-VLV)
TTC0 = 5

    S7.3. Stopped lead vehicle.
    S7.3.1. Test parameters.
    (a) For testing with no subject vehicle manual brake application, 
the subject vehicle test speed is any speed between 10 km/h and 80 km/
h, and the lead vehicle speed is 0 km/h.
    (b) For testing with manual brake application of the subject 
vehicle, the subject vehicle test speed is any speed between 70 km/h 
and 100 km/h, and the lead vehicle speed is 0 km/h.
    S7.3.2. Test conduct prior to forward collision warning onset.
    (a) The lead vehicle is placed stationary with its longitudinal 
centerline coincident to the intended travel path.
    (b) Before the headway corresponds to L0, the subject 
vehicle is driven at any speed, in any direction, on any road surface, 
for any amount of time.
    (c) The subject vehicle approaches the rear of the lead vehicle.
    (d) Beginning when the headway corresponds to L0, the 
subject vehicle speed is maintained within 1.6 km/h of the test speed 
with minimal and smooth accelerator pedal inputs.
    (e) Beginning when the headway corresponds to L0, the 
subject vehicle heading is maintained with minimal steering input such 
that the travel path does not deviate more than 0.3 m laterally from 
the intended travel path and the subject vehicle's yaw rate does not 
exceed 1.0 deg/s.
    S7.3.3. Test conduct after forward collision warning onset.
    (a) The accelerator pedal is released at any rate such that it is 
fully released within 500 ms. This action is omitted for vehicles 
tested with cruise control active.

[[Page 38724]]

    (b) For testing conducted with manual brake application, the 
service brakes are applied as specified in S10. The onset of brake 
pedal application occurs 1.0 0.1 second after forward 
collision warning onset.
    (c) For testing conducted without manual brake application, no 
manual brake application is made until the test completion criteria of 
S7.3.4 are satisfied.
    S7.3.4. Test completion criteria. The test run is complete when the 
subject vehicle comes to a complete stop without making contact with 
the lead vehicle or when the subject vehicle makes contact with the 
lead vehicle.
    S7.4. Slower-moving lead vehicle.
    S7.4.1. Test parameters.
    (a) For testing with no subject vehicle manual brake application, 
the subject vehicle test speed is any speed between 40 km/h and 80 km/
h, and the lead vehicle speed is 20 km/h.
    (b) For testing with manual brake application of the subject 
vehicle, the subject vehicle test speed is any speed between 70 km/h 
and 100 km/h, and the lead vehicle speed is 20 km/h.
    S7.4.2. Test conduct prior to forward collision warning onset.
    (a) The lead vehicle is propelled forward in a manner such that the 
longitudinal center plane of the lead vehicle does not deviate 
laterally more than 0.3m from the intended travel path.
    (b) The subject vehicle approaches the lead vehicle.
    (c) Beginning when the headway corresponds to L0, the 
subject vehicle and lead vehicle speed is maintained within 1.6 km/h of 
the test speed with minimal and smooth accelerator pedal inputs.
    (d) Beginning when the headway corresponds to L0, the 
subject vehicle and lead vehicle headings are be maintained with 
minimal steering input such that the subject vehicle's travel path does 
not deviate more than 0.3 m laterally from the centerline of the lead 
vehicle, and the yaw rate of the subject vehicle does not exceed 1.0 deg/s prior to the forward collision warning onset.
    S7.4.3. Test conduct after forward collision warning onset.
    (a) The subject vehicle's accelerator pedal is released at any rate 
such that it is fully released within 500 ms. This action is omitted 
for vehicles tested with cruise control active.
    (b) For testing conducted with manual braking application, the 
service brakes are applied as specified in S10. The onset of brake 
pedal application is 1.0 0.1 second after the forward 
collision warning onset.
    (c) For testing conducted without manual braking application, no 
manual brake application is made until the test completion criteria of 
S7.4.4 are satisfied.
    S7.4.4. Test completion criteria. The test run is complete when the 
subject vehicle speed is less than or equal to the lead vehicle speed 
without making contact with the lead vehicle or when the subject 
vehicle makes contact with the lead vehicle.
    S7.5. Decelerating lead vehicle.
    S7.5.1. Test parameters.
    (a) The subject vehicle test speed is 50 km/h or 80 km/h, and the 
lead vehicle speed is identical to the subject vehicle test speed.
    (b) [Reserved]
    S7.5.2. Test conduct prior to lead vehicle braking onset.
    (a) Before the 3 seconds prior to lead vehicle braking onset, the 
subject vehicle is be driven at any speed, in any direction, on any 
road surface, for any amount of time.
    (b) Between 3 seconds prior to lead vehicle braking onset and lead 
vehicle braking onset:
    (1) The lead vehicle is propelled forward in a manner such that the 
longitudinal center plane of the vehicle does not deviate laterally 
more than 0.3 m from the intended travel path.
    (2) The subject vehicle follows the lead vehicle at a headway of 
any distance between 12 m and 40 m.
    (3) The subject vehicle's speed is maintained within 1.6 km/h of 
the test speed with minimal and smooth accelerator pedal inputs prior 
to forward collision warning onset.
    (4) The lead vehicle's speed is maintained within 1.6 km/h.
    (5) The subject vehicle and lead vehicle headings are maintained 
with minimal steering input such that their travel paths do not deviate 
more than 0.3 m laterally from the centerline of the lead vehicle, and 
the yaw rate of the subject vehicle does not exceed 1.0 
deg/s until onset of forward collision warning.
    S7.5.3. Test conduct following lead vehicle braking onset.
    (a) The lead vehicle is decelerated to a stop with a targeted 
average deceleration of any value between 0.3g and 0.5g. The targeted 
deceleration magnitude is achieved within 1.5 seconds of lead vehicle 
braking onset and is maintained until 250 ms prior to coming to a stop.
    (b) After forward collision warning onset, the subject vehicle's 
accelerator pedal is released at any rate such that it is fully 
released within 500 ms. This action is omitted for vehicles with cruise 
control active.
    (c) For testing conducted with manual braking application, the 
service brakes are applied as specified in S10. The brake pedal 
application onset occurs 1.0 0.1 second after the forward 
collision warning onset.
    (d) For testing conducted without manual braking application, no 
manual brake application is made until the test completion criteria of 
S7.5.4 are satisfied.
    S7.5.4. Test completion criteria. The test run is complete when the 
subject vehicle comes to a complete stop without making contact with 
the lead vehicle or when the subject vehicle makes contact with the 
lead vehicle.
    S8. Testing when approaching a pedestrian.
    S8.1. Setup.
    S8.1.1. General.
    (a) For reference, Table 2 to S8.1.1 specifies the subject vehicle 
speed (VSV), the pedestrian test mannequin speed 
(VP), the overlap of the pedestrian test mannequin, and the 
lighting condition for each test that may be conducted.
    (b) The intended travel path of the vehicle is a straight line 
originating at the location corresponding to a headway of 
L0.
    (c) If the road surface is marked with a single or double lane 
line, the intended travel path is parallel to and 1.8 m from the inside 
of the closest line. If the road surface is marked with two lane lines 
bordering the lane, the intended travel path is centered between the 
two lines.
    (d) For each test run conducted, the subject vehicle speed 
(VSV) will be selected from the range specified.

                                            Table 2 to S8.1.1--Test Parameters When Approaching a Pedestrian
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                             Speed (km/h)
                                         Direction          Overlap (%)         Obstructed       ------------------------------------ Lighting condition
                                                                                                          VSV               VP
--------------------------------------------------------------------------------------------------------------------------------------------------------
Crossing Path...................  Right.................              25  No....................  Any 10-60.........               5  Daylight.
                                  Right.................              50  No....................  Any 10-60.........                  Daylight.

[[Page 38725]]

 
                                  Right.................              50  No....................  Any 10-60 *.......                  Lower Beams.
                                  Right.................              50  No....................  Any 10-60.........                  Upper Beams.
                                  Right.................              50  Yes...................  Any 10-50.........                  Daylight.
                                  Left..................              50  No....................  Any 10-60.........               8  Daylight.
Stationary......................  Right.................              25  No....................  Any 10-55.........               0  Daylight.
                                                                                                  Any 10-55 *.......                  Lower Beams.
                                                                                                  Any 10-55.........                  Upper Beams.
Along-Path......................  Right.................              25  No....................  Any 10-65.........               5  Daylight.
                                                                                                  Any 10-65 *.......                  Lower Beams.
                                                                                                  Any 10-65 *.......                  Upper Beams.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Lower speed performance test requirements apply prior to [the first September 1 that is four years after publication of a final rule]. See S5(b).

    S8.1.2. Overlap. As depicted in Figure 1 to this section, overlap 
describes the location of the point on the front of the subject vehicle 
that would make contact with a pedestrian if no braking occurred. 
Overlap is the percentage of the subject vehicle's overall width that 
the pedestrian test mannequin traverses. It is measured from the right 
or the left, depending on the side of the subject vehicle where the 
pedestrian test mannequin originates. For each test run, the actual 
overlap will be within 0.15 m of the specified overlap.
    S8.1.3. Pedestrian Test Mannequin.
    (a) For testing where the pedestrian test mannequin is secured to a 
moving apparatus, the pedestrian test mannequin is secured so that it 
faces the direction of motion. The pedestrian test mannequin leg 
articulation starts on apparatus movement and stops when the apparatus 
stops.
    (b) For testing where the pedestrian test mannequin is stationary, 
the pedestrian test mannequin faces away from the subject vehicle, and 
the pedestrian test mannequin legs remain still.
    S8.2. Headway calculation. For each test run conducted under S8.3, 
S8.4, and S8.5, the headway (L0), in meters, between the 
front plane of the subject vehicle and a parallel contact plane on the 
pedestrian test mannequin providing 4.0 seconds time to collision (TTC) 
is calculated. L0 is determined with the following equation 
where VSV is the speed of the subject vehicle in m/s and 
VP-y is the component of speed of the pedestrian test 
mannequin in m/s in the direction of the intended travel path:

L0 = TTC0 x (VSV - VP-y)
TTC0 = 4.0

    S8.3. Pedestrian crossing road.
    S8.3.1. Test parameters and setup (unobstructed from right).
    (a) The testing area is set up in accordance with Figure 3 to this 
section.
    (b) Testing is conducted in the daylight or darkness conditions, 
except that testing with the pedestrian at the 25 percent overlap is 
only conducted in daylight conditions.
    (c) Testing is conducted using the adult pedestrian test mannequin.
    (d) The movement of the pedestrian test mannequin is perpendicular 
to the subject vehicle's intended travel path.
    (e) The pedestrian test mannequin is set up 4.0 0.1 m 
to the right of the intended travel path.
    (f) The intended overlap is 25 percent from the right or 50 
percent.
    (g) The subject vehicle test speed is any speed between 10 km/h and 
60 km/h.
    (h) The pedestrian test mannequin speed is 5 km/h.
    S8.3.2 Test parameters and setup (unobstructed from left).
    (a) The testing area is set up in accordance with Figure 4 to this 
section.
    (b) Testing is conducted in the daylight condition.
    (c) Testing is conducted using the adult pedestrian mannequin.
    (d) The movement of the pedestrian test mannequin is perpendicular 
to the intended travel path.
    (e) The pedestrian test mannequin is set up 6.0 0.1 m 
to the left of the intended travel path.
    (f) The intended overlap is 50 percent.
    (g) The subject vehicle test speed is any speed between 10 km/h and 
60 km/h.
    (h) The pedestrian test mannequin speed is 8 km/h.
    S8.3.3. Test parameters and setup (obstructed).
    (a) The testing area is set up in accordance with Figure 5 to this 
section.
    (b) Testing is conducted in the daylight condition.
    (c) Testing is conducted using the child pedestrian test mannequin.
    (d) The movement of the pedestrian test mannequin is perpendicular 
to the intended travel path.
    (e) The pedestrian test mannequin is set up 4.0 0.1 m 
to the right of the intended travel path.
    (f) The intended overlap is 50 percent.
    (g) Two vehicle test devices are secured in stationary positions 
parallel to the intended travel path. The two vehicle test devices face 
the same direction as the intended travel path. One vehicle test device 
is directly behind the other separated by 1.0 0.1 m. The 
left side of each vehicle test device is 1.0 0.1 m to the 
right of the vertical plane parallel to the intended travel path and 
tangent with the right outermost point of the subject vehicle when the 
subject vehicle is in the intended travel path.
    (h) The subject vehicle test speed is any speed between 10 km/h and 
50 km/h.
    (i) The pedestrian test mannequin speed is 5 km/h.
    S8.3.4. Test conduct prior to forward collision warning or vehicle 
braking onset.
    (a) The subject vehicle approaches the crossing path of the 
pedestrian test mannequin.
    (b) Beginning when the headway corresponds to L0, the 
subject vehicle speed is maintained within 1.6 km/h of the test speed 
with minimal and smooth accelerator pedal inputs.
    (c) Beginning when the headway corresponds to L0, the 
subject vehicle heading is maintained with minimal steering inputs such 
that the subject vehicle's travel path does not deviate more than 0.3 m 
laterally from the intended travel path, and the yaw rate of the 
subject vehicle does not exceed 1.0 deg/s prior to any 
automated braking onset.
    (d) The pedestrian test mannequin apparatus is triggered at a time 
such that the pedestrian test mannequin meets the intended overlap, 
subject to the criteria in S8.1.2. The pedestrian test mannequin 
achieves its intended speed within 1.5 m after the apparatus begins to 
move and maintains its intended speed within 0.4 km/h until the test

[[Page 38726]]

completion criteria of S8.3.6 are satisfied.
    S8.3.5. Test conduct after either forward collision warning or 
vehicle braking onset.
    (a) After forward collision warning or vehicle braking onset, the 
subject vehicle's accelerator pedal is released at any rate such that 
it is fully released within 500 ms. This action is omitted for vehicles 
with cruise control active.
    (b) No manual brake application is made until the test completion 
criteria of S8.3.6 are satisfied.
    (c) The pedestrian mannequin continues to move until the completion 
criteria of S8.3.6 are satisfied.
    S8.3.6. Test completion criteria. The test run is complete when the 
subject vehicle comes to a complete stop without making contact with 
the pedestrian test mannequin, when the pedestrian test mannequin is no 
longer in the path of the subject vehicle, or when the subject vehicle 
makes contact with the pedestrian test mannequin.
    S8.4. Stationary pedestrian.
    S8.4.1. Test parameters and setup.
    (a) The testing area is set up in accordance with Figure 6 to this 
section.
    (b) Testing is conducted in the daylight or darkness conditions.
    (c) Testing is conducted using the adult pedestrian test mannequin.
    (d) The pedestrian mannequin is set up at the 25 percent right 
overlap position facing away from the approaching vehicle.
    (e) The subject vehicle test speed is any speed between 10 km/h and 
55 km/h.
    (f) The pedestrian mannequin is stationary.
    S8.4.2. Test conduct prior to forward collision warning or vehicle 
braking onset.
    (a) The subject vehicle approaches the pedestrian test mannequin.
    (b) Beginning when the headway corresponds to L0, the 
subject vehicle speed is maintained within 1.6 km/h of the test speed 
with minimal and smooth accelerator pedal inputs.
    (c) Beginning when the headway corresponds to L0, the 
subject vehicle heading is maintained with minimal steering inputs such 
that the subject vehicle's travel path does not deviate more than 0.3 m 
laterally from the intended travel path, and the yaw rate of the 
subject vehicle does not exceed 1.0 deg/s prior to any 
automated braking onset.
    S8.4.3. Test conduct after either forward collision warning or 
vehicle braking onset.
    (a) After forward collision warning or vehicle braking onset, the 
subject vehicle's accelerator pedal is released at any rate such that 
it is fully released within 500 ms. This action is omitted with 
vehicles with cruise control active.
    (b) No manual brake application is made until the test completion 
criteria of S8.4.4 are satisfied.
    S8.4.4. Test completion criteria. The test run is complete when the 
subject vehicle comes to a complete stop without making contact with 
the pedestrian test mannequin, or when the subject vehicle makes 
contact with the pedestrian test mannequin.
    S8.5. Pedestrian moving along the path
    S8.5.1. Test parameters and setup.
    (a) The testing area is set up in accordance with Figure 7 to this 
section.
    (b) Testing is conducted in the daylight or darkness conditions.
    (c) Testing is conducted using the adult pedestrian test mannequin.
    (d) The movement of the pedestrian test mannequin is parallel to 
and in the same direction as the subject vehicle.
    (e) The pedestrian test mannequin is set up in the 25 percent right 
offset position.
    (f) The subject vehicle test speed is any speed between 10 km/h and 
65 km/h.
    (g) The pedestrian test mannequin speed is 5 km/h.
    S8.5.2. Test conduct prior to forward collision warning or vehicle 
braking onset.
    (a) The subject vehicle approaches the pedestrian test mannequin.
    (b) Beginning when the headway corresponds to L0, the 
subject vehicle speed is maintained within 1.6 km/h of the test speed 
with minimal and smooth accelerator pedal inputs.
    (c) Beginning when the headway corresponds to L0, the 
subject vehicle heading is maintained with minimal steering inputs such 
that the travel path does not deviate more than 0.3 m laterally from 
the intended travel path, and the yaw rate of the subject vehicle does 
not exceed 1.0 deg/s prior to any automated braking onset.
    (d) The pedestrian test mannequin apparatus is triggered any time 
after the distance between the front plane of the subject vehicle and a 
parallel contact plane on the pedestrian test mannequin corresponds to 
L0. The pedestrian test mannequin achieves its intended 
speed within 1.5 m after the apparatus begins to move and maintains its 
intended speed within 0.4 km/h until the test completion criteria of 
S8.5.4 are satisfied.
    S8.5.3. Test conduct after either forward collision warning or 
vehicle braking onset.
    (a) After forward collision warning or vehicle braking onset, the 
subject vehicle's accelerator pedal is released at any rate such that 
it is fully released within 500 ms. This action is omitted for vehicles 
with cruise control active.
    (b) No manual brake application is made until the test completion 
criteria of S8.5.4 are satisfied.
    S8.5.4. Test completion criteria. The test run is complete when the 
subject vehicle slows to speed below the pedestrian test mannequin 
travel speed without making contact with the pedestrian test mannequin 
or when the subject vehicle makes contact with the pedestrian test 
mannequin.
    S9. False AEB activation.
    S9.1. Headway calculation. For each test run to be conducted under 
S9.2 and S9.3, the headway (L0, L2.1, L1.1), in meters, between the 
front plane of the subject vehicle and either the steel trench plate's 
leading edge or the rearmost plane normal to the centerline of the 
vehicle test devices providing 5.0 seconds, 2.1 seconds, and 1.1 
seconds time to collision (TTC) is calculated. L0, L2.1, and L1.1 are 
determined with the following equation where VSV is the speed of the 
subject vehicle in m/s:

Lx = TTCx x (VSV)
TTC0 = 5.0
TTC2.1 = 2.1
TTC1.1 = 1.1

    S9.2. Steel trench plate.
    S9.2.1. Test parameters and setup.
    (a) The testing area is set up in accordance with Figure 8.
    (b) The steel trench plate is secured flat on the test surface so 
that its longest side is parallel to the vehicle's intended travel path 
and horizontally centered on the vehicle's intended travel path.
    (c) The subject vehicle test speed is 80 km/h.
    (d) Testing may be conducted with manual brake application.
    S9.2.2. Test conduct.
    (a) The subject vehicle approaches the steel trench plate.
    (b) Beginning when the headway corresponds to L0, the 
subject vehicle speed is maintained within 1.6 km/h of the test speed 
with minimal and smooth accelerator pedal inputs.
    (c) Beginning when the headway corresponds to L0, the 
subject vehicle heading is maintained with minimal steering input such 
that the travel path does not deviate more than 0.3 m laterally from 
the intended travel path, and the yaw rate of the subject vehicle does 
not exceed 1.0 deg/s.
    (d) If forward collision warning occurs, the subject vehicle's 
accelerator pedal is released at any rate such that it is fully 
released within 500 ms. This action is omitted for vehicles with cruise 
control active.

[[Page 38727]]

    (e) For tests where no manual brake application occurs, manual 
braking is not applied until the test completion criteria of S9.2.3 are 
satisfied.
    (f) For tests where manual brake application occurs, the subject 
vehicle's accelerator pedal, if not already released, is released when 
the headway corresponds to L2.1 at any rate such that it is 
fully released within 500 ms.
    (g) For tests where manual brake application occurs, the service 
brakes are applied as specified in S10. The brake application pedal 
onset occurs at headway L1.1.
    S9.2.3. Test completion criteria. The test run is complete when the 
subject vehicle comes to a stop prior to crossing over the leading edge 
of the steel trench plate or when the subject vehicle crosses over the 
leading edge of the steel trench plate.
    S9.3. Pass-through.
    S9.3.1. Test parameters and setup.
    (a) The testing area is set up in accordance with Figure 9.
    (b) Two vehicle test devices are secured in a stationary position 
parallel to one another with a lateral distance of 4.5 m 0.1 m between the vehicles' closest front wheels. The centerline 
between the two vehicles is parallel to the intended travel path.
    (c) The subject vehicle test speed is 80 km/h.
    (d) Testing may be conducted with manual subject vehicle pedal 
application.
    S9.3.2. Test conduct.
    (a) The subject vehicle approaches the gap between the two vehicle 
test devices.
    (b) Beginning when the headway corresponds to L0, the 
subject vehicle speed is maintained within 1.6km/h with minimal and 
smooth accelerator pedal inputs.
    (c) Beginning when the headway corresponds to L0, the 
subject vehicle heading is maintained with minimal steering input such 
that the travel path does not deviate more than 0.3 m laterally from 
the intended travel path, and the yaw rate of the subject vehicle does 
not exceed 1.0 deg/s.
    (d) If forward collision warning occurs, the subject vehicle's 
accelerator pedal is released at any rate such that it is fully 
released within 500 ms.
    (e) For tests where no manual brake application occurs, manual 
braking is not applied until the test completion criteria of S9.3.3 are 
satisfied.
    (f) For tests where manual brake application occurs, the subject 
vehicle's accelerator pedal, if not already released, is released when 
the headway corresponds to L2.1 at any rate such that it is 
fully released within 500 ms.
    (g) For tests where manual brake application occurs, the service 
brakes are applied as specified in S10. The brake application onset 
occurs when the headway corresponds to L1.1.
    S9.3.3. Test completion criteria. The test run is complete when the 
subject vehicle comes to a stop prior to its rearmost point passing the 
vertical plane connecting the forwardmost point of the vehicle test 
devices or when the rearmost point of the subject vehicle passes the 
vertical plane connecting the forwardmost point of the vehicle test 
devices.
    S10. Subject Vehicle Brake Application Procedure.
    S10.1. The procedure begins with the subject vehicle brake pedal in 
its natural resting position with no preload or position offset.
    S10.2. At the option of the manufacturer, either displacement 
feedback or hybrid feedback control is used.
    S10.3. Displacement feedback procedure. For displacement feedback, 
the commanded brake pedal position is the brake pedal position that 
results in a mean deceleration of 0.4g in the absence of AEB system 
activation.
    (a) The mean deceleration is the deceleration over the time from 
the pedal achieving the commanded position to 250 ms before the vehicle 
comes to a stop.
    (b) The pedal displacement controller depresses the pedal at a rate 
of 254 mm/s 25.4 mm/s to the commanded brake pedal 
position.
    (c) The pedal displacement controller may overshoot the commanded 
position by any amount up to 20 percent. If such an overshoot occurs, 
it is corrected within 100 ms.
    (d) The achieved brake pedal position is any position within 10 
percent of the commanded position from 100 ms after pedal displacement 
occurs and any overshoot is corrected.
    S10.4. Hybrid brake pedal feedback procedure. For hybrid brake 
pedal feedback, the commanded brake pedal application is the brake 
pedal position and a subsequent commanded brake pedal force that 
results in a mean deceleration of 0.4g in the absence of AEB system 
activation.
    (a) The mean deceleration is the deceleration over the time from 
the pedal achieving the commanded position to 250 ms before the vehicle 
comes to a stop.
    (b) The hybrid controller displaces the pedal at a rate of 254 mm/s 
25.4 mm/s to the commanded pedal position.
    (c) The hybrid controller may overshoot the commanded position by 
any amount up to 20 percent. If such an overshoot occurs, it is 
corrected within 100 ms.
    (d) The hybrid controller begins to control the force applied to 
the pedal and stops controlling pedal displacement 100 ms after pedal 
displacement occurs and any overshoot is corrected.
    (e) The hybrid controller applies a pedal force of at least 11.1 N.
    (f) The applied pedal force is maintained within 10 percent of the 
commanded brake pedal force from 350 ms after commended pedal 
displacement occurs and any overshoot is corrected until test 
completion.

Figure 1 to Sec.  571.127--Percentage Overlap Nomenclature

[[Page 38728]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.050

Figure 2 to Sec.  571.127--Setup for Lead Vehicle Automatic Emergency 
Braking
[GRAPHIC] [TIFF OMITTED] TP13JN23.051

Figure 3 to Sec.  571.127--Setup for Pedestrian, Crossing Path, Right

[[Page 38729]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.052

Figure 4 to Sec.  571.127--Setup for Pedestrian, Crossing Path, Left

[[Page 38730]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.053

Figure 5 to Sec.  571.127--Setup for Pedestrian, Obstructed

[[Page 38731]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.054

Figure 6 to Sec.  571.127--Setup for Pedestrian Along-Path Stationary

[[Page 38732]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.055

Figure 7 to Sec.  571.127--Setup for Pedestrian Along-Path Moving

[[Page 38733]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.056

Figure 8 to Sec.  571.127--Steel Trench Plate
[GRAPHIC] [TIFF OMITTED] TP13JN23.057

Figure 9 to Sec.  571.127--Pass-Through

[[Page 38734]]

[GRAPHIC] [TIFF OMITTED] TP13JN23.058

0
4. Add part 596 to read as follows.

PART 596--AUTOMATIC EMERGENCY BRAKING TEST DEVICES

0
1. The authority citation for part 596 reads as follows:

    Authority:  49 U.S.C. 322, 30111, 30115, 30117 and 30166; 
delegation of authority at 49 CFR 1.95.
Sec.
Subpart A--General
596.1 Scope.
596.2 Purpose.
596.3 Application
596.4 Definitions.
596.5 Matter incorporated by reference.
Subpart B--Pedestrian Test Devices
596.7 Specifications for pedestrian test devices.
596.8 [Reserved]
Subpart C--Vehicle Test Device
596.9 General Description
596.10 Specifications for the Vehicle Test Device

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

Subpart A--General


Sec.  596.1  Scope.

    This part describes the test devices that are to be used for 
compliance testing of motor vehicles with motor vehicle safety 
standards for automatic emergency braking.


Sec.  596.2  Purpose.

    The design and performance criteria specified in this part are 
intended to describe devices with sufficient precision such that 
testing performed with these test devices will produce repetitive and 
correlative results under similar test conditions to reflect adequately 
the automatic emergency braking performance of a motor vehicle.


Sec.  596.3  Application.

    This part does not in itself impose duties or liabilities on any 
person. It is a description of tools that are used in compliance tests 
to measure the performance of automatic emergency braking systems 
required by the safety standards that refer to these tools. This part 
is designed to be referenced by, and become part of, the test 
procedures specified in motor vehicle safety standards, such as 49 CFR 
571.127 (Standard No. 127, Automatic emergency braking systems for 
light vehicles).


Sec.  596.4  Definitions.

    All terms defined in section 30102 of the National Traffic and 
Motor Vehicle Safety Act (49 U.S.C. chapter 301, et seq.) are used in 
their statutory meaning.
    Adult Pedestrian Test Mannequin (APTM) means a test device with the 
appearance and radar cross section that simulates an adult pedestrian 
for the purpose of testing automatic emergency brake system 
performance.
    Child Pedestrian Test Mannequin (CPTM) means a test device with the 
appearance and radar cross section that stimulates a child pedestrian 
for the purpose of testing automatic emergency brake system 
performance.
    Vehicle Test Device means a test device that simulates a passenger 
vehicle for the purpose of testing automatic emergency brake system 
performance.
    Vehicle Test Device Carrier means a movable platform on which a 
Lead Vehicle Test Device may be attached during compliance testing.
    Pedestrian Test Device(s) means an Adult Pedestrian Test Mannequin 
and/or a Child Pedestrian Test Mannequin.
    Pedestrian Test Mannequin Carrier means a movable platform on which 
an Adult Pedestrian Test Mannequin or Child Pedestrian Test Mannequin 
may be attached during compliance testing.


Sec.  596.5  Matter incorporated by reference.

    (a) Certain material is incorporated by reference into this part 
with the approval of the Director of the Federal Register under 5 
U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other than that 
specified in this section, the National Highway Traffic Safety 
Administration (NHTSA) must publish notice of change in the Federal 
Register and the material must be available to the public. All approved 
material is available for inspection at NHTSA at the National Archives 
and Records Administration (NARA). Contact NHTSA at: NHTSA Office of 
Technical Information Services, 1200 New Jersey Avenue SE, Washington, 
DC 20590; (202) 366-2588 and For information on the availability of 
this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations.htmlor email [email protected]. The material may be 
obtained from the source(s) in the following paragraph of this section.
    (b) International Organization for Standardization (ISO), 1, ch. de 
la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland; phone: + 41 22 
749 01 11 fax: + 41 22 733 34 30; website: www.iso.org/.
    (1) ISO 3668:2017, ``Paints and varnishes--Visual comparison of 
colour of paints,'' Third edition, 2017-05; into Sec.  596.7.
    (2) ISO 19206-2:2018(E), ``Road vehicles--Test devices for target 
vehicles, vulnerable road users and other objects, for assessment of 
active safety functions--Part 2: Requirements for pedestrian targets,'' 
First edition, 2018-12; into Sec.  596.7.
    (3) ISO 19206-3:2021(E), ``Test devices for target vehicles, 
vulnerable road users and other objects, for assessment of active 
safety functions--Part 3: Requirements for passenger vehicle 3D 
targets,'' First edition, 2021-05; into Sec.  596.10.
    (4) ISO I9206-4:2020(E), ``Test devices for target vehicles, 
vulnerable road users and other objects, for assessment of active 
safety functions--Part 4: Requirements for bicyclist targets,'' First 
edition, 2020-11; into Sec.  596.7.

Subpart B--Pedestrian Test Devices


Sec.  596.7  Specifications for Pedestrian Test Devices.

    (a) The words ``recommended,'' ``should,'' ``can be,'' or ``should 
be'' appearing in sections of ISO 19206-2:2018(E) (incorporated by 
reference, see Sec.  596.5), referenced in this section, are read as 
setting forth specifications that are used.
    (b) The words ``may be,'' or ``either'' used in connection with a 
set of items

[[Page 38735]]

appearing in sections of ISO 19206-2:2018(E) (incorporated by 
reference, see Sec.  596.5), referenced in this section, are read as 
setting forth the totality of items, any one of which may be selected 
by NHTSA for testing.
    (c) Specifications for the Pedestrian Test Devices--(1) General 
description. The Adult Pedestrian Test Mannequin (APTM) provides a 
sensor representation of a 50th percentile adult male and consist of a 
head, torso, two arms and hands, and two legs and feet. The Child 
Pedestrian Test Mannequin (CPTM) provides a sensor representation of a 
6-7-year-old child and consists of a head, torso, two arms and hands, 
and two legs and feet. The arms of the APTM and CPTM are posable, but 
do not move during testing. The legs of the APTM and CPTM articulate 
and are synchronized to the forward motion of the mannequin.
    (2) Dimensions and posture. The APTM has basic body dimensions and 
proportions specified in Annex A, table A.1 in ISO 19206-2:2018 
(incorporated by reference, see Sec.  596.5). The CPTM has basic body 
dimensions and proportions specified in Annex A, table A.1 in ISO 
19206-2:2018 (incorporated by reference, see Sec.  596.5).
    (3) Visual Properties--(i) Head. The head has a visible hairline 
silhouette by printed graphic. The hair is black as defined in Annex B 
table B.2 of ISO 19206-4:2020, as tested in accordance with ISO 
3668:2017 (both incorporated by reference, see Sec.  596.5).
    (ii) Face. The head does not have any facial features (i.e., eyes, 
nose, mouth, and ears).
    (iii) Skin. The face, neck and hands have a skin colored as defined 
Annex B, table B.2 of ISO 19206-4: 2020 (incorporated by reference, see 
Sec.  596.5).
    (iv) Torso and Arms. The torso and arms are black as defined in 
Annex B table B.2 of ISO 19206-4:2020, as tested in accordance with ISO 
3668:2017 (both incorporated by reference, see Sec.  596.5).
    (v) Legs. The legs are blue as defined in Annex B table B.2 of ISO 
19206-4:2020, as tested in accordance with ISO 3668:2017 (both 
incorporated by reference, see Sec.  596.5).
    (vi) Feet. The feet are black as defined in Annex B table B.2 of 
ISO 19206-4:2020, as tested in accordance with ISO 3668:2017 (both 
incorporated by reference, see Sec.  596.5).
    (4) Infrared properties. The surface of the entire APTM or CPTM are 
within the reflectivity ranges specified in Annex B section B.2.2 of 
ISO 19206-2:2018, as illustrated in Annex B, figure B.2 (incorporated 
by reference, see Sec.  596.5).
    (5) Radar properties. The radar reflectivity characteristics of the 
pedestrian test device approximates that of a pedestrian of the same 
size when approached from the side or from behind.
    (6) Radar cross section measurements. The radar cross section 
measurements of the APTM and the CPTM is within the upper and lower 
boundaries shown in Annex B, section B.3, figure B.6 of ISO 19206-
2:2018 when tested in accordance with the measure procedure in Annex C, 
section C.3 of ISO 19206-2:2018 (incorporated by reference, see Sec.  
596.5).
    (7) Posture. The pedestrian test device has arms that are posable 
and remain posed during testing. The pedestrian test device is equipped 
with moving legs consistent with standard gait phases specified in 
Section 5.6 of ISO 19206-2:2018 (incorporated by reference, see Sec.  
596.5).
    (8) Articulation Properties. The legs of the pedestrian test device 
are in accordance with, and as described in, Annex D, section D.2 and 
illustrated in Figures D.1, D.2, and D.3 of ISO 19206-2:2018 
(incorporated by reference, see Sec.  596.6).


Sec.  596.8  [Reserved]

Subpart C--Vehicle Test Device


Sec.  596.9  General Description

    (a) The Vehicle Test Device provides a sensor representation of a 
passenger motor vehicle.
    (b) The rear view of the Vehicle Test Device contains 
representations of the vehicle silhouette, a rear window, a high-
mounted stop lamp, two taillamps, a rear license plate, two rear reflex 
reflectors, and two tires.


Sec.  596.10  Specifications for the Vehicle Test Device.

    (a) The words ``recommended,'' ``should,'' ``can be,'' or ``should 
be'' appearing in sections of ISO 19206-3:2021(E) (incorporated by 
reference, see Sec.  596.5), referenced in this section, are read as 
setting forth specifications that are used.
    (b) The words ``may be,'' or ``either,'' used in connection with a 
set of items appearing in sections of ISO 19206-3:2021(E) (incorporated 
by reference, see Sec.  596.5), referenced in this section, are read as 
setting forth the totality of items, any one of which may be selected 
by NHTSA for testing.
    (c) Dimensional specifications. (1) The rear silhouette and the 
rear window are symmetrical about a shared vertical centerline.
    (2) Representations of the taillamps, rear reflex reflectors, and 
tires are symmetrical about the surrogate's centerline.
    (3) The license plate representation has a width of 300 15 mm and a height of 150 15 mm and mounted with a 
license plate holder angle within the range described in 49 CFR 571.108 
S6.6.3.1.
    (4) The Vehicle Test Device representations are located within the 
minimum and maximum measurement values specified in columns 3 and 4 of 
Tables A.4 of ISO 19206-3:2021(E) Annex A (incorporated by reference, 
see Sec.  596.5). The tire representations are located within the 
minimum and maximum measurement values specified in columns 3 and 4 of 
Tables A.3 of ISO 19206-3:2021(E) Annex A (incorporated by reference, 
see Sec.  596.5). The terms ``rear light'' means ``taillamp,'' 
``retroreflector'' means ``reflex reflector,'' and ``high centre 
taillight'' means ``high-mounted stop lamp.''
    (d) Visual and near infrared specification. (1) The Vehicle Test 
Device rear representation colors are within the ranges specified in 
Tables B.2 and B.3 of ISO 19206-3:2021(E) Annex B (incorporated by 
reference, see Sec.  596.5).
    (2) The rear representation infrared properties of the Vehicle Test 
Device are within the ranges specified in Table B.1 of ISO 19206-
3:2021(E) Annex B (incorporated by reference, see Sec.  596.5) for 
wavelengths of 850 to 950 nm when measured according to the calibration 
and measurement setup specified in paragraph B.3 of ISO 19206-3:2021(E) 
Annex B (incorporated by reference, see Sec.  596.5).
    (3) The Vehicle Test Device rear reflex reflectors, and at least 50 
cm\2\ of the taillamp representations are grade DOT-C2 reflective 
sheeting as specified in 49 CFR 571.108 S8.2.
    (e) Radar reflectivity specifications. (1) The radar cross section 
of the Vehicle Test Device is measured with it attached to the carrier 
(robotic platform). The radar reflectivity of the carrier platform is 
less than 0 dBm\2\ for a viewing angle of 180 degrees and over a range 
of 5 to 100 m when measured according to the radar measurement 
procedure specified in C.3 of ISO 19206-3:2021(E) Annex C (incorporated 
by reference, see Sec.  596.5) for fixed-angle scans.
    (2) The rear bumper area as shown in Table C.1 of ISO 19206-
3:2021(E) Annex C (incorporated by reference, see Sec.  596.5) 
contributes to the target radar cross section.
    (3) The radar cross section is assessed using radar sensor that 
operates at 76 to 81 GHz and has a range of at least 5 to

[[Page 38736]]

100 m, a range gate length smaller than 0.6m, a horizontal field of 
view of 10 degrees or more (-3dB amplitude limit), and an elevation 
field of view of 5 degrees or more (-3dB amplitude).
    (4) At least 92 percent of the filtered data points of the 
surrogate radar cross section for the fixed vehicle angle, variable 
range measurements are within the radar cross section boundaries 
defined in Sections C.2.2.4 of ISO 19206-3:2021(E) Annex C 
(incorporated by reference, see Sec.  596.5) for a viewing angle of 180 
degrees when measured according to the radar measurement procedure 
specified in C.3 of ISO 19206-3:2021(E) Annex C (incorporated by 
reference, see Sec.  596.5) for fixed-angle scans.
    (5) Between 86 to 95 percent of the Vehicle Test Device spatial 
radar cross section reflective power is with the primary reflection 
region defined in Section C.2.2.5 of ISO 19206-3:2021(E) Annex C 
(incorporated by reference, see Sec.  596.5) when measured according to 
the radar measurement procedure specified in C.3 of ISO 19206-3:2021(E) 
Annex C (incorporated by reference, see Sec.  596.5) using the angle-
penetration method.

    Issued under authority delegated in 49 CFR part 1.95 and 49 CFR 
501.8.
Raymond R. Posten,
Associate Administrator for Rulemaking.
[FR Doc. 2023-11863 Filed 6-12-23; 8:45 am]
BILLING CODE 4910-59-P