Rule2024-09054
Federal Motor Vehicle Safety Standards; Automatic Emergency Braking Systems for Light Vehicles
Primary source
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Published
May 9, 2024
Effective
July 8, 2024
Issuing agencies
Transportation DepartmentNational Highway Traffic Safety Administration
Abstract
This final rule adopts 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. This final rule specifies that an AEB system must detect and react to an imminent crash with both a lead vehicle or a pedestrian. This final rule fulfills a mandate under the Bipartisan Infrastructure Law (BIL) directing the Department to promulgate a rule to require that all passenger vehicles be equipped with an AEB system. The purpose of this final rule 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, and to reduce the consequences of such crashes.
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[Federal Register Volume 89, Number 91 (Thursday, May 9, 2024)]
[Rules and Regulations]
[Pages 39686-39795]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-09054]
[[Page 39685]]
Vol. 89
Thursday,
No. 91
May 9, 2024
Part II
Department of Transportation
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National Highway Traffic Safety Administration
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49 CFR Parts 571, 595, and 596
Federal Motor Vehicle Safety Standards; Automatic Emergency Braking
Systems for Light Vehicles; Final Rule
Federal Register / Vol. 89 , No. 91 / Thursday, May 9, 2024 / Rules
and Regulations
[[Page 39686]]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Parts 571, 595, 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: Final rule.
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SUMMARY: This final rule adopts 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. This
final rule specifies that an AEB system must detect and react to an
imminent crash with both a lead vehicle or a pedestrian. This final
rule fulfills a mandate under the Bipartisan Infrastructure Law (BIL)
directing the Department to promulgate a rule to require that all
passenger vehicles be equipped with an AEB system. The purpose of this
final rule 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, and to reduce
the consequences of such crashes.
DATES:
Effective Date: This rule is effective July 8, 2024.
IBR date: The incorporation by reference of certain material listed
in the rule is approved by the Director of the Federal Register
beginning July 8, 2024. The incorporation by reference of certain other
material listed in the rule was approved by the Director of the Federal
Register as of July 8, 2022.
Compliance Date: September 1, 2029. However, vehicles produced by
small-volume manufacturers, final-stage manufacturers, and alterers
must be equipped with a compliant AEB system by September 1, 2030.
Petitions for reconsideration: Petitions for reconsideration of
this final rule must be received not later than June 24, 2024.
ADDRESSES: Petitions for reconsideration of this final rule must refer
to the docket number set forth above (NHTSA-2023-0021) and be submitted
to the Administrator, National Highway Traffic Safety Administration,
1200 New Jersey Avenue SE, Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: For technical issues: Mr. Markus
Price, Office of Crash Avoidance Rulemaking, Telephone: 202-366-1810,
Facsimile: 202-366-7002. For legal issues: Ms. Sara R. Bennett, Office
of the Chief Counsel, Telephone: 202-366-2992, Facsimile: 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: This final rule adopts a new Federal Motor
Vehicle Safety Standard (FMVSS) No. 127 to require automatic emergency
braking (AEB), including pedestrian AEB (PAEB), systems on light
vehicles. FMVSS No. 127 applies to all passenger cars and to all
multipurpose passenger vehicles (MPVs), trucks, and buses with a gross
vehicle weight rating (GVWR) of 4,536 kilograms (kg) (10,000 pounds
(lbs.)) or less (``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.
This final rule specifies that an AEB system must detect and react
to an imminent crash with both a lead vehicle and a pedestrian. This
final rule advances DOT's January 2022 National Roadway Safety
Strategy, which identified a requirement for AEB, including PAEB
technologies, on new passenger vehicles as a key Departmental action to
improve vehicle and pedestrian safety. Finally, this final rule
fulfills section 24208(a) of BIL, which directs the Secretary of
Transportation to promulgate a rule to require that all passenger
vehicles be equipped with an AEB system.
NHTSA published the notice of proposed rulemaking preceding this
final rule on June 13, 2023 (88 FR 38632).
Table of Contents
I. Executive Summary
II. Background
A. The Safety Problem
B. Bipartisan Infrastructure Law (BIL)
C. High-level Summary of Comments on the NPRM
D. Summary of the Notice of Proposed Rulemaking
E. Additional Research Conducted in 2023
III. Final Rule and Response to Comments
A. Summary of the Final Rule (and Modifications to the NPRM)
B. Application
C. Definitions
D. FCW and AEB Equipment Requirements
1. Minimum Activation Speed
2. Maximum Activation Speed
3. Environmental Conditions
E. AEB System Requirements (Applies to Lead Vehicle and
Pedestrian)
1. Forward Collision Warning Requirements
a. FCW Signal Modality
b. FCW Auditory Signal Requirements
c. FCW Auditory Signal Presentation with Simultaneous Muting of
Other In-Vehicle Audio
d. FCW Visual Symbol Requirements
e. FCW Visual Signal Location Requirements
2. AEB Requirement
a. AEB Deactivation
b. Aftermarket Modifications
c. No-Contact Requirement for Lead Vehicle AEB
d. No-Contact Requirement for Pedestrians
e. Permissibility of Failure
F. False Activation Requirement
1. Need for Requirement
2. Peak Additional Deceleration
3. Process Standard Documentation as Alternative to False
Activation Requirements
4. Data Storage Requirement as Alternative to False Activation
Requirements
G. Malfunction Detection Requirement
1. Need for Requirement
2. Malfunction Telltale
3. Sensor Obstructions and Testing
H. Procedure for Testing Lead Vehicle AEB
1. Scenarios
2. Subject Vehicle Speed Ranges
3. Headway
4. Lead Vehicle Deceleration
5. Manual Brake Application
6. Testing Setup and Completion
7. Miscellaneous Comments
I. Procedures for Testing PAEB
1. Scenarios
2. Subject Vehicle Speed Ranges
3. Pedestrian Test Device Speed
4. Overlap
5. Light Conditions
6. Testing Setup
J. Procedures for Testing False Activation
K. Track Testing Conditions
1. Environmental Test Conditions
2. Road/Test Track Conditions
L. Vehicle Test Device
1. General Description
2. Definitions
3. Sideview Specification
4. Field Verification Procedure
5. Dimensional Specification
6. Visual and Near Infrared Specification
7. Radar Reflectivity
8. List of Actual Vehicles
M. Pedestrian Test Devices
1. General Description
2. Dimensions and Posture
3. Visual Properties
4. Radar Properties
[[Page 39687]]
5. Articulation Properties
6. Comments on Thermal Characteristics
N. Miscellaneous Topics
O. Effective Date and Phase-In Schedule
IV. Summary of Estimated Effectiveness, Cost, and Benefits
A. Benefits
B. Costs
C. Net Impact
V. Regulatory Notices and Analyses
VI. Appendices to the Preamble
A. Appendix A: Description of the Lead Vehicle AEB Test
Procedures
B. Appendix B: Description of the PAEB Test Procedures
C. Appendix C: Description of the False Activation Test
Procedures
I. Executive Summary
In 2019, prior to the COVID-19 pandemic, there were nearly 2.2
million rear-end police-reported crashes involving light vehicles,
which led to 1,798 deaths and 574,000 injuries. In addition, 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. Deaths and injuries in more recent years are
even greater.
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\1\ <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813079">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813079</a> Pedestrian Traffic Facts 2019 Data, May 2021.
\2\ Id., Table 1 Pedestrian fatalities 2010--4,302, 2019--6,272.
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NHTSA is issuing this final rule to address these significant
safety problems through a new Federal Motor Vehicle Safety Standard
that requires all light vehicles be equipped with forward collision
warning (FCW),\3\ automatic emergency braking (AEB), and pedestrian
automatic emergency braking (PAEB) technology.\4\ AEB systems reduce
the frequency and severity of lead vehicle and pedestrian collisions.
They 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.
These systems can reduce both lead vehicle rear-end (lead vehicle AEB)
and pedestrian (PAEB) crashes. AEB systems have reached a level of
maturity to make a significant contribution to reducing the frequency
and severity of crashes and are thus ready to be mandated through
adoption of a new FMVSS on all new light vehicles.
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\3\ A forward collision warning (FCW) system uses sensors that
detect objects in front of vehicles and provides an alert to the
driver. An FCW system is able to use the sensors' input to determine
the speed of an object in front of it and the distance between the
vehicle and the object. If the FCW system determines that the
closing distance and velocity between the vehicle and the object is
such that a collision may be imminent, the system is designed to
induce an immediate forward crash avoidance response by the vehicle
operator. FCW systems may detect impending collisions with any
number of roadway obstacles, including vehicles and pedestrians.
Warning systems in use today provide drivers with a visual warning
signal, 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.
\4\ Hereafter, when this final rule 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.
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This rule is estimated to save at least 362 lives and mitigate
24,321 non-fatal injuries a year. It 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 roadways, including those
involving pedestrians.\5\
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\5\ <a href="https://www.transportation.gov/sites/dot.gov/files/2022-01/USDOT_National_Roadway_Safety_Strategy_0.pdf">https://www.transportation.gov/sites/dot.gov/files/2022-01/USDOT_National_Roadway_Safety_Strategy_0.pdf</a>.
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The crash problem that the agency seeks to address with the AEB
requirements in this final rule is substantial.\6\ For example, 60
percent of fatal rear-end crashes and 73 percent of crashes resulting
in injuries 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
crashes resulting in injuries. Also, about 51 percent of fatal rear-end
crashes and 74 percent of rear-end crashes resulting in injuries, all
involving light vehicles, 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.
Finally, 77 percent of pedestrian fatalities, and about half of the
pedestrian injuries, occur in dark lighting conditions. Importantly,
this final rule requires that PAEB systems be able to avoid pedestrian
crashes in dark testing conditions.
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\6\ 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).
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This final rule 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),\7\ which added 49 U.S.C. 30129, directing the
Secretary of Transportation to promulgate a rule requiring that all
passenger motor vehicles manufactured for sale in the United States be
equipped with an FCW system and an AEB system.
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\7\ Public Law 117-58, 24208 (Nov. 15, 2021).
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The Focus on AEB
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 the New Car Assessment Program (NCAP) in 2010 and reporting on the
research and progress surrounding the technologies shortly
thereafter.\8\ These research efforts led to NHTSA listing FCW systems
as a ``recommended advanced technology'' in NCAP in model year 2011,
and in November 2015, added crash imminent braking (CIB) \9\ and
dynamic brake support (DBS) technologies to the program.\10\ Most
recently, NHTSA proposed upgrades to the lead vehicle AEB test in its
March 2022 request for comment on NCAP.\11\
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\8\ 77 FR 39561 (Jul. 2, 2012).
\9\ This final rule does not split the terminology of these CIB
and DBS functionalities outside of certain contexts, like
discussions of NCAP, but instead considers them both as parts of
AEB. The final rule includes performance tests that would require an
AEB system that has both CIB and DBS functionalities.
\10\ 80 FR 68604 (Nov. 5, 2015).
\11\ 87 FR 13452 (Mar. 9, 2022). See <a href="https://www.regulations.gov">https://www.regulations.gov</a>, docket number NHTSA-2021-0002.
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In March 2016, NHTSA and the 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 include low-speed
AEB as a standard feature on nearly all new light vehicles not later
than September 1,
[[Page 39688]]
2022. As part of this voluntary commitment, manufacturers are including
both FCW and a CIB system that reduces a vehicle's speed in certain
rear-end crash-imminent test conditions.
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 research,
the agency 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.\12\ 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 in NCAP.\13\
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\12\ 84 FR 64405 (Nov. 21, 2019).
\13\ 87 FR 13452 (Mar. 9, 2022).
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Need for Regulation
While the above 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 appropriate and 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.\14\ Similarly, the voluntary commitment
resulted in approximately 90 percent of new light vehicles manufactured
in 2022 having an AEB system.
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\14\ 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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That said, the test speeds and performance specifications in NCAP
and the voluntary commitment do 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.
Voluntary measures are intended to supplement rather than
substitute for the FMVSSs, which remain NHTSA's core method of ensuring
that all motor vehicles can achieve an adequate level of safety
performance. The NCAP program is designed to provide valuable safety-
related information to consumers in a simple to understand way, but 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, only regulation can ensure that all
vehicles are equipped with AEB that meet minimum performance
requirements.
These considerations are of even greater weight when deciding
whether to require a system that can reduce pedestrian crashes, and the
agency has concluded that PAEB is both achievable and necessary.
Pedestrian fatalities are increasing, and NHTSA's testing reveals that
PAEB systems will be able to significantly reduce these deaths.\15\
Manufacturers' responses to adding lead vehicle AEB and other
technologies to NCAP suggest that it will take several years after PAEB
is introduced to NCAP before the market begins to see significant
numbers of new vehicles that are able to meet a finalized NCAP test.
Even so, since PAEB addresses the safety of someone other than a
vehicle occupant, it is not clear if past experience with NCAP is
necessarily indicative of how quickly PAEB systems will reach the
market penetration levels of lead vehicle AEB.
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\15\ NHTSA's accompanying Final Regulatory Impact Analysis
(FRIA) estimates the impacts of this final rule. The FRIA can be
found in the docket for this final rule. The docket number is listed
in the heading of this document.
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A final factor weighing in favor of requiring AEB is that the
technology is significantly more mature now than it was at the time of
the voluntary commitment and when it was introduced into NCAP. NHTSA's
most recent testing has shown that higher performance levels than those
in the voluntary commitment or the existing NCAP requirements are now
practicable. Many model year 2019 and 2020 vehicles were able to
repeatedly avoid impacting the lead vehicle in CIB tests and the
pedestrian test mannequin in PAEB tests, even at higher test speeds
than those prescribed currently in the agency's CIB and PAEB test
procedures.
These results show that AEB systems can reduce 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.
Summary of the NPRM
In view of the significant safety problem and NHTSA's recent test
results, and consistent with the Safety Act and BIL, on June 13, 2023
(88 FR 38632) NHTSA published an NPRM proposing a new FMVSS requiring
AEB systems that can address both lead vehicle and pedestrian
collisions on all new light vehicles. The proposed lead vehicle AEB
test procedures built on the existing FCW, CIB, and DBS NCAP
procedures, but proposed higher speed performance requirements. Crash
avoidance was proposed 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. NHTSA proposed testing under both daylight and
darkness lighting conditions, noting the importance of darkness testing
of PAEB because more than three-fourths of all pedestrian fatalities
occur in conditions other than daylight.
The proposal included four requirements for the AEB system for both
lead vehicles and pedestrians. The AEB system would be required to: (1)
provide an FCW at any forward speed greater than 10 km/h (6.2 mph),
presented via auditory and visual modalities, with permissible
additional warning modes, such as haptic; (2) apply 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, including
at speeds above those tested by NHTSA; (3) prevent the vehicle from
colliding with the lead vehicle or pedestrian test mannequin when
tested according to the proposed test procedures, which would include
pedestrian tests in both daylight and darkness and two false positive
tests; and (4) provide visual notification to the driver of any
malfunction that causes the AEB system not to meet the minimum proposed
performance requirements.
To ensure test repeatability, NHTSA proposed specifications for the
test devices that would be used in both the lead vehicle and pedestrian
compliance tests, relying in large part on relevant International
Organization for Standardization standards.
[[Page 39689]]
NHTSA proposed that all vehicles manufactured four years after the
publication date of a final rule would be required to meet all
requirements. NHTSA also proposed that all vehicles manufactured on or
after three years after the publication date of a final rule would be
required to meet all requirements except that lower speed PAEB
performance test requirements would not 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.
NHTSA sought comments on all aspects of the NPRM and any
alternative requirements that would address the safety problem. In
response, over 1,000 comments were received from a wide variety of
stakeholders and interested persons. These comments are available in
the docket for the NPRM.\16\
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\16\ <a href="https://www.regulations.gov/docket/NHTSA-2023-0021/comments">https://www.regulations.gov/docket/NHTSA-2023-0021/comments</a>.
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This Final Rule
After careful consideration of all comments, this final rule adopts
most of the proposed NPRM requirements, with a few of the changes
relevant to significant matters. The differences between the NPRM and
the final rule are noted at the end of this Executive Summary and
discussed in the relevant sections of this preamble.
With this final rule, NHTSA has issued a Final Regulatory Impact
Analysis (FRIA), available in the docket for this final rule (NHTSA-
2023-0021).
NHTSA estimates that systems can achieve the requirements of this
final rule primarily through upgraded software, with a limited number
of vehicles needing additional hardware. Therefore, the incremental
cost associated with this 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 rule and
the cost to equip a second sensor (radar) on five percent of the
estimated fleet that is not projected to have the needed hardware.
Taking into account both software and hardware costs, the total annual
cost associated with this final rule is approximately $354 million in
2020 dollars.
Table 1 below summarizes the finding of the benefit-cost analysis.
The projected benefits of this rule greatly exceed the projected costs.
The lifetime monetized net benefit of this rule is projected to be
between $5.82 and $7.26 billion with a cost per equivalent life saved
of between $550,000 and $680,000, which is far below the Department's
recommended value of a statistical life saved, of as $11.6 million in
2020 dollars.
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Differences Between This Final Rule and the NPRM
NHTSA has made a number of changes to the NPRM based on information
from the comments. The changes are discussed below. NHTSA discusses
each of these changes in the relevant sections of this preamble.
<bullet> In the NPRM, NHTSA estimated that systems can achieve the
proposed requirements through upgraded software alone. Commenters
suggested that in some instances additional hardware will also be
needed, so the incremental cost associated with this rule now includes
the cost of a software upgrade and the cost to equip a second sensor
(radar) on the five percent of the estimated fleet that does not now
have the needed hardware.
<bullet> NHTSA has made changes to lead time and compliance date
requirements. The NPRM proposed that all vehicles comply with the
requirements within 3 years, except for some higher speed PAEB
performance requirements in darkness (which had 1 year more to comply
than other requirements). This final rule requires that manufacturers
comply with all provisions of the rule at the end of a 5-year period
starting the first September 1 following publication of this rule,
which would be September 1, 2029.\17\ The requirements of this final
rule compel robust AEB systems that are practicable, but the agency has
determined that more time is needed for the technology to mature and be
deployed into all vehicles.\18\ We expect that many vehicles will be
equipped with AEB systems that meet the new rule earlier than September
1, 2029, because of redesign schedules, but that manufacturers will be
able to meet the requirement for all new vehicles by the new start
date.
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\17\ As proposed in the NPRM, this final rule provides small-
volume manufacturers, final stage manufacturers, and alterers an
additional year of lead time. As a result of the changes to the
proposed lead time and compliance date requirements, small-volume
manufactures, final stage manufactures, and alterers would be
required to comply with all provisions of the rule starting
September 1, 2030.
\18\ As part of this extension of the lead time, the agency has
removed the graduated approach to the PAEB performance requirements.
The NPRM proposed that most PAEB requirements be met 3 years after a
final rule, with an additional year for the dark lighting condition
requirement. With the 5-year lead time for all requirements, there
is no need for the phasing-in of requirements, so the agency is not
adopting it.
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<bullet> This final rule modifies the range of forward speeds at
which the AEB must operate. The NPRM required FCW and AEB systems to
operate at any forward speed greater than 10 km/h. This final rule
places an upper bound on the requirement that an AEB system operate of
145 km/h (90.1 mph) for FCW and lead vehicle AEB and 73 km/h (45.4 mph)
for pedestrian AEB. This final rule also clarifies the environmental
conditions under which the AEB system must perform to be the same
environmental conditions specified in the track testing.
<bullet> This final rule includes an explicit prohibition against
manufacturers installing a control designed for the sole purpose of
deactivation of the AEB system, except where provided below as it
relates to law enforcement. This final rule also allows for controls
that have the ancillary effect of deactivating the AEB system. For
instance, a manufacturer may choose to deactivate AEB if the driver has
activated ``tow mode'' and the manufacturer has determined that AEB
cannot perform safely while towing a trailer.
<bullet> This final rule modifies the FCW visual signal location
requirement to increase the specified maximum visual angle from 10
degrees to 18 degrees in the vertical direction. This change from the
NPRM provides manufacturers with the flexibility to locate the visual
warning signal within the typical area of the upper half of the
instrument panel and closer to the central field of view of the driver.
While the agency continues to believe that an FCW visual warning signal
presented near the central forward-looking region is ideal, it does not
consider a head-up display to be necessary for the presentation of the
FCW visual signal that is part of a complete AEB system.
<bullet> The rule contains several additional minor changes as
well. These include the following:
--In the obstructed pedestrian scenario in PAEB performance tests, the
NPRM did not specify the distance between the pedestrian test dummy and
the farthest obstructing vehicle. This final rule corrects this
oversight.
--In the false activation tests, this final rule adjusts the regulatory
text to clarify that testing for false activation is done with and
without manual brake application.
--Some minor parameters and definitions were modified, and various
definitions were added, to clarify details of the lead vehicle and PAEB
test procedures.
--To increase practicability of running the tests, a third manual brake
application controller option, a force only feedback controller, was
added. The force feedback controller is substantially similar to the
hybrid controller with the commanded brake pedal position omitted,
leaving only the commanded brake pedal force application.
--The procedure in Annex C, section C.3 of ISO 19206-2:2018 is specific
for pedestrian targets, but recent testing performed by the agency
indicates that the three-position measurement specified in Annex C,
section C.3 of ISO 19206-3:2021 provides more reduction in multi-path
reflections and offers more accurate radar cross section values. The
agency is incorporating by reference ISO 19206-3:2021.
II. Background
A. The 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
42,795 for 2022.\19\ 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,\20\ agency
data show an increase of 3,356 fatalities between 2010 and 2019.\21\
Motor vehicle crashes have also trended upwards since 2010, which
corresponds to an increase in fatalities, injuries, and property
damage.
---------------------------------------------------------------------------
\19\ <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813266">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813266</a>, <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813428">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813428</a>.
\20\ 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.
\21\ NHTSA's Traffic Safety Facts Annual Report, Table 2,
<a href="https://cdan.nhtsa.gov/tsftables/tsfar.htm#Accessed">https://cdan.nhtsa.gov/tsftables/tsfar.htm#Accessed</a> March 28, 2023.
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[[Page 39691]]
Overall Rear-End Crash Problem
NHTSA uses data from the 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.\22\
---------------------------------------------------------------------------
\22\ <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813251">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813251</a> Category II Configuration D. Rear-End.
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In 2019, rear-end crashes accounted for 32.5 percent of all
crashes, making them the most prevalent type of crash.\23\ 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, and data from 2022
are not yet available, 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 differences 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).
---------------------------------------------------------------------------
\23\ <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141</a> Traffic Safety Facts 2019, Table 29.
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BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TR09MY24.004
The table below 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.
---------------------------------------------------------------------------
\24\ Compiled from NHTSA's Traffic Safety Facts Annual Report,
Table 29 from 2010 to 2020, <a href="https://cdan.nhtsa.gov/tsftables/tsfar.htm#Accessed">https://cdan.nhtsa.gov/tsftables/tsfar.htm#Accessed</a> March 28, 2023.
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[[Page 39692]]
[GRAPHIC] [TIFF OMITTED] TR09MY24.005
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.
---------------------------------------------------------------------------
\25\ NHTSA's Traffic Safety Facts Annual Report, Table 29 for
2019, <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141</a> Accessed March 29, 2024.
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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.'' \26\ 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.\27\
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\26\ <a href="https://www-fars.nhtsa.dot.gov/help/terms.aspx">https://www-fars.nhtsa.dot.gov/help/terms.aspx</a>.
\27\ NHTSA's Traffic Safety Facts Annual Report, 2019, <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141</a>.
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[[Page 39693]]
[GRAPHIC] [TIFF OMITTED] TR09MY24.006
Rear-End Crashes by Posted Speed Limit
---------------------------------------------------------------------------
\28\ Generated from FARS and CRSS databases (<a href="https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/">https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/</a>,
<a href="https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/">https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/</a>,
accessed October 17, 2022).
---------------------------------------------------------------------------
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. The table below 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.
[GRAPHIC] [TIFF OMITTED] TR09MY24.007
Rear-End Crashes by Light Condition
---------------------------------------------------------------------------
\29\ Generated from FARS and CRSS databases (<a href="https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/">https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/</a>,
<a href="https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/">https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/</a>,
accessed October 17, 2022).
\30\ Total percentages may not equal the sum of individual
components due to independent rounding throughout the Safety Problem
section.
---------------------------------------------------------------------------
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. 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. The table below 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.
[[Page 39694]]
[GRAPHIC] [TIFF OMITTED] TR09MY24.008
Rear-End Crashes by Atmospheric Conditions
---------------------------------------------------------------------------
\31\ Generated from FARS and CRSS databases (<a href="https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/">https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/</a>,
<a href="https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/">https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/</a>,
accessed October 17, 2022).
---------------------------------------------------------------------------
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 summary of 2019 rear-end
crashes of light vehicle with frontal impact by atmospheric conditions
is presented in the table below.
---------------------------------------------------------------------------
\32\ Generated from FARS and CRSS databases (<a href="https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/">https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/</a>,
<a href="https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/">https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/</a>,
accessed October 17, 2022).
[GRAPHIC] [TIFF OMITTED] TR09MY24.009
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 increased to 6,272 (17 percent of all
fatalities) in 2019. The latest agency estimation data indicate that
there were 7,345 pedestrian fatalities in 2022.\33\ Since data from
2020 and 2021 may not be representative of the general safety problem
due to the COVID-19 pandemic and data for 2022 are early estimates, 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. As shown in
the table below, 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.
---------------------------------------------------------------------------
\33\ <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813448">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813448</a>.
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[[Page 39695]]
[GRAPHIC] [TIFF OMITTED] TR09MY24.010
The following sections present a breakdown of pedestrian fatalities
and injuries by initial impact point, vehicle type, posted speed limit,
lighting condition, and pedestrian age for the year 2019.
---------------------------------------------------------------------------
\34\ <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813079">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813079</a> Pedestrian Traffic Facts 2019 Data, May 2021,
<a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813310">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813310</a>
Pedestrian Traffic Facts 2020, Data May 2022.
---------------------------------------------------------------------------
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 the table below).\35\
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\35\ As described previously, passenger cars and light trucks
are the representative population for vehicles with a gross vehicle
weight rating (GVWR) of 4,536 kg (10,000 lbs.) or less.
[GRAPHIC] [TIFF OMITTED] TR09MY24.011
Pedestrian Fatalities and Injuries by Posted Speed Limit Involving
Light Vehicles
---------------------------------------------------------------------------
\36\ NHTSA's Traffic Safety Facts Annual Report, Table 99 for
2019, <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141</a> Accessed March 29, 2024.
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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 or not reported). As for pedestrian injuries, in 34
percent of the sampled data, the posted speed limit is either not
reported or unknown. In
[[Page 39696]]
2019, 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 with the remaining not reported, reported as unknown,
or reported as no speed limit. The table below shows the number of
pedestrian fatalities and injuries for each posted speed limit.
[GRAPHIC] [TIFF OMITTED] TR09MY24.012
Pedestrian Fatalities and Injuries by Lighting Condition Involving
Light Vehicles
---------------------------------------------------------------------------
\37\ The accompanying FRIA 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.
---------------------------------------------------------------------------
The majority of pedestrian fatalities where the front of a light
vehicle strikes a pedestrian 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.
[[Page 39697]]
[GRAPHIC] [TIFF OMITTED] TR09MY24.013
Pedestrian Fatalities and Injuries by Age Involving Light Vehicles
---------------------------------------------------------------------------
\38\ Generated from FARS and CRSS databases (<a href="https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/">https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/</a>,
<a href="https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/">https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/</a>,
accessed October 17, 2022).
---------------------------------------------------------------------------
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 the table below, the first
two age groups (under age 5 and ages 5 to 9) each represent less than 1
percent of the total pedestrian fatalities in crashes with the front of
a light vehicle. These age groups also represent about 1.5 and 3.8
percent of the total pedestrian injuries in crashes with the front of a
light vehicle, respectively. In contrast, age groups between age 25 and
69 each represent approximately 7 percent of the total pedestrian
fatalities in crashes with the front of a light vehicle, with the 55 to
59 age group having the highest percentage at 10.9 percent. Pedestrian
injury percentages were less consistent, but distributed similarly, to
pedestrian fatalities, with lower percentages reflected in children
aged 9 and below and adults over age 70.
[[Page 39698]]
[GRAPHIC] [TIFF OMITTED] TR09MY24.014
BILLING CODE 4910-59-C
B. Bipartisan Infrastructure Law (BIL)
---------------------------------------------------------------------------
\39\ Generated from FARS and CRSS databases (<a href="https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/">https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/FARS/2019/National/</a>,
<a href="https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/">https://www.nhtsa.gov/file-downloads?p=nhtsa/downloads/CRSS/2019/</a>,
accessed October 17, 2022).
\40\ <a href="https://www.census.gov/data/tables/2019/demo/age-and-sex/2019-age-sex-composition.html">https://www.census.gov/data/tables/2019/demo/age-and-sex/2019-age-sex-composition.html</a>, Table 12.
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This final rule responds to Congress's directive that NHTSA require
AEB on all passenger vehicles. On November 15, 2021, the President
signed the Bipartisan Infrastructure Law, codified as the
Infrastructure Investment and Jobs Act (Pub. L. 117-58). 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 manufactured for sale in the United
States be equipped with a forward collision warning (FCW) system and an
automatic emergency braking system. 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
[[Page 39699]]
the brakes if the driver fails to do so. This final rule responds to
this mandate and is estimated 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.
BIL requires that ``all passenger motor vehicles'' manufactured for
sale in the United States be equipped with AEB and FCW. The BIL term
``passenger motor vehicle'' encompasses more vehicle categories than
the term ``passenger car'' that NHTSA defines in 49 CFR 571.3. Thus,
including multipurpose passenger vehicles, trucks, and buses aligns
with Congress's mandate. Additionally, NHTSA considers passenger cars,
truck, buses, and multipurpose passenger vehicles as light vehicles and
generally uses the 10,000 GVWR cut-off for FMVSS that apply to light
vehicles.\41\ As a result, in this final rule, NHTSA requires AEB and
FCW on all passenger cars and multipurpose passenger vehicles, trucks,
and buses with a gross vehicle weight rating (GVWR) of 10,000 lbs. or
less.
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\41\ See, for example, 49 CFR 571.138, 571.208, and 571.111.
---------------------------------------------------------------------------
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.
NHTSA interprets BIL as requiring AEB capable of detecting and
responding to vehicles and objects and authorizing NHTSA to promulgate
specific performance requirements. NHTSA's rule requires light vehicles
to be equipped with FCW and automatic emergency braking (AEB), and the
proposal defines AEB as a system that detects an imminent collision
with vehicles, objects, and road users,\42\ in or near the path of a
vehicle and automatically controls the vehicle's service brakes to
avoid or mitigate the collision.
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\42\ While AEB is defined as a system that detects imminent
collision with vehicles, objects, and road users, the performance
requirements focus on protecting pedestrians until NHTSA can develop
additional research to support a proposal to expand the performance
requirements.
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As discussed in the NPRM, section 24208 of BIL does not limit
NHTSA's broad authority to issue motor vehicle safety regulations under
the Safety Act. NHTSA interprets BIL as a mandate to act on a
particular vehicle safety issue and as complementary to NHTSA's
authority under the Safety Act. Thus, pursuant to its authority under
49 U.S.C 30111, NHTSA is requiring all light passenger vehicles to be
equipped with PAEB in addition to AEB. NHTSA is ensuring that PAEB is
available on all light passenger vehicles to address a significant
safety problem, and in so doing, recognizes the availability of
technology capable of preventing needless injuries and lost lives.
C. High-level Summary of Comments on the NPRM
NHTSA received more than a thousand comments on the proposed rule.
The agency received comments from a wide variety of commenters
including advocacy groups, manufacturers, trade associations,
suppliers, and individuals. The advocacy groups submitting comments
included AAA Inc. (AAA), AARP, Advocates for Highway and Auto Safety
(Advocates), America Walks, American Foundation for the Blind (AFB),
Association of Pedestrian and Bicycle Professionals (APBP), Center for
Auto Safety (CAS), Consumer Reports, DRIVE SMART Virginia, Insurance
Institute for Highway Safety (IIHS), International Association of Fire
Chiefs, Intelligent Transportation Society of America (ITS America),
League of American Bicyclists (League), McHenry County Bicycle
Advocates, National Safety Council (NSC), Paralyzed Veterans of America
(PVA), United Spinal Association, Utah Public Lands Alliance, and
Vulnerable Road Users Safety Consortium (VRUSC). Trade associations
submitting comments included Alliance for Automotive Innovation
(Alliance), American Chemistry Council, American Motorcyclist
Association (AMA), Automotive Safety Council (ASC), Autonomous Vehicle
Industry Association (AVIA), the Governors Highway Safety Association
(GHSA), Lidar Coalition, the Motor and Equipment Manufacturers
Association (MEMA), National Automotive Dealers Association (NADA),
National Association of City Transportation Officials (NACTO),
Association for the Work Truck Industry (NTEA), SAE International
(SAE), and Specialty Equipment Market Association (SEMA). We also
received comments from individual vehicle manufacturers such as FCA US
LLC (FCA), Ford Motor Company (Ford), General Motors LLC (GM), American
Honda Motor, Co., Inc. (Honda), Hyundai Motor Company (Hyundai),
Mitsubishi Motors R & D of America, Inc. (Mitsubishi), Nissan North
America, Inc. (Nissan), Porsche Cars North America (Porsche), Rivian
Automotive, LLC (Rivian), Toyota Motor North America, Inc. (Toyota),
and Volkswagen Group of America (Volkswagen). Suppliers and developers
commenting on the NPRM included Adasky North America (Adasky), Applied
Intuition (Applied), Aptiv, Automotive Electronics Products COMPAL
Electronics, Inc. (COMPAL), Autotalks, Forensic Rock, LLC (Forensic
Rock), Humanetics Safety (Humanetics), Hyundai America Technical
Center, Inc. (HATCI), Hyundai MOBIS, imagery Inc. (Imagery), LHP Inc.
(LHP), Luminar Technologies, Inc. (Luminar), Mobileye Vision
Technologies LTD (Mobileye), Owl Autonomous Imaging, Inc. (Owl AI),
Radian Labs LLC (Radian), Robert Bosch LLC (Bosch), Teledyne FLIR
(Teledyne), ZF North America (ZF), and Zoox, Inc. (Zoox). Government
agencies that commented included the National Transportation Safety
Board (NTSB), the City of Houston (Houston), City of Philadelphia
(Philadelphia), Humboldt County Association of Governments, Maryland
Department of Transportation Motor Vehicle Administration (MDOT),
Multnomah County, and Nashville Department of Transportation and
Multimodal Infrastructure (Nashville). Healthcare and insurance
companies submitting comments included American Property Casualty
Insurance Association (APCIA), National Association of Mutual Insurance
Companies, and Richmond Ambulance Authority. The agency also received
approximately 970 comments from individual commenters. In general, the
commenters expressed support for the goals of this rulemaking, and many
commenters offered recommendations on the most appropriate way to
achieve those goals.
Many commenters shared their general support for requiring AEB as
standard equipment on passenger vehicles, while others opposed
finalizing the proposed rule for various technical and policy reasons.
In general, safety advocates supported finalizing the rule, while
vehicle manufacturers opposed various aspects of the proposal, even if
they expressed general support for AEB technology. The agency received
comments on many aspects of the rule, including comments on the
application, the performance requirements, the test procedure
conditions and parameters, and the proposed lead time and phase-in
schedule.
Consumer advocacy groups primarily supported the rule, with
concerns regarding manual deactivation and the proposed requirements
regarding PAEB. They urged that any conditions for AEB deactivation be
restricted and have data supporting deactivation and asserted that any
manual deactivation would need to have multiple steps and require the
vehicle to be stationary. Many suggested that the testing speeds be
increased to cover a larger portion of the safety problem. Another
concern raised
[[Page 39700]]
by advocacy groups was the lack of test procedures covering bicyclists
and users of mobility devices and wheelchairs. They recommended that
the agency add more PAEB testing scenarios, noting that there is a
significant safety risk for pedestrians and all vulnerable road users.
In general, advocacy groups supported the full collision avoidance, no-
contact requirement for all proposed AEB tests as a necessity to uphold
the strength of the rule.
While vehicle manufacturers supported the installation of AEB, the
most significant concerns focused on the stringency of the
requirements. The NPRM proposed the AEB system be operational at any
forward speed above 10 km/h (6.2 mph). Several vehicle manufacturers
and the Alliance opposed the open-ended upper bound, stating it was
impracticable or that it would lead to false activations. These
commenters stated that the lack of a defined maximum operational speed
could create implementation ambiguity and difficulty complying with the
rule due to significant development costs. The NPRM further proposed
full collision avoidance with the lead vehicle during AEB testing (a
no-contact performance requirement). The Alliance, and multiple
manufacturers expressing support for the Alliance' comments, stated
that a no-contact performance requirement is not practicable and
increases the potential for unintended consequences such as inducing
unstable vehicle dynamics, removing the driver's authority, increasing
false activations, and creating conditions that limit bringing new
products to market. These commenters asserted that a lack of rigorous
testing by the agency leaves questions as to actual vehicle performance
in the field.
The vehicle manufacturers also commented on the feasibility of
specific performance requirements under the proposed phase-in schedule,
arguing that the agency was mistaken to assume in the NPRM that most
vehicles have the necessary hardware to implement this rule. They
commented that the proposed phase-in schedule may require redesigns to
their systems outside of the normal product development cycle and
contended that such a scenario would significantly increase the costs
and burdens of compliance. The manufacturers requested that the agency
delay the rule by as much as eight years to afford them time to
redesign their systems in conjunction with the normal vehicle redesign
schedule.
Manufacturers and suppliers generally opposed the agency's proposal
to prohibit manual deactivation of the AEB system above 10km/h.
Commenters stated the need for deactivation during various scenarios,
including four-wheel drive operation, towing, off-road use, car washes
and low traction driving. There were multiple suggestions to adopt the
deactivation criteria of the United Nations Economic Commission for
Europe (UNECE) Regulation No. 152, in place of the NPRM proposed
criteria, and to align with UNECE Regulation No. 152 more generally.
Among suppliers and developers, there was not a consensus on the
no-contact requirement. Commenters such as Adasky and Luminar expressed
support for the no-contact requirement, stating that current technology
is capable of this performance. ZF, Aptiv, and Hyundai MOBIS believed
the proposed no-contact requirement was not practicable and suggested
harmonization with UNECE Regulation No. 152. Generally, those opposed
to the no-contact requirement supported hybrid or speed reduction
approaches.\43\
---------------------------------------------------------------------------
\43\ A kind of hybrid approach would maintain no-contact
requirements for lower-mid-range speeds while permitting contact at
higher speed if acceptable speed reductions that reduce the risk of
serious injury can be achieved in the higher-speed scenarios.
---------------------------------------------------------------------------
ZF, HATCI, and Aptiv supported the ability to manually deactivate
the AEB system and recommended harmonization with UNECE Regulation No.
152 deactivation criteria. Imagry opposed the entirety of the NPRM as
drawing resources and development away from fully autonomous driving,
while Autotalks supported the regulation as ``urgently needed.''
Finally, most individual commenters expressed general support to
the goals of this rule, citing the vulnerability of pedestrians on or
near roadways. A significant portion of these commenters also noted
that children, people with dark skin tones, and those using a
wheelchair or mobility device are particularly vulnerable. Individual
commenters opposed to this rule cited concerns about off-road operation
and false activation.
D. Summary of the Notice of Proposed Rulemaking
NHTSA published the NPRM for this final rule on June 2, 2023 (88 FR
38632). Because this final rule adopts almost all of the requirements
proposed in the NPRM, this summary is brief and mirrors the description
of the final rule provided in the Executive Summary, supra.
1. The NPRM proposed creating a new FMVSS to require AEB systems on
light vehicles that can reduce the frequency and severity of both rear-
end and pedestrian crashes. The proposed AEB performance requirements
were intended to ensure that an AEB system is able to automatically and
completely avoid collision with the rear of another vehicle or a
pedestrian in specific combinations of scenarios and speeds, while
continuing to alert and apply the brakes at speeds beyond those in the
test procedure.
2. The NPRM proposed four requirements for the AEB systems. The
proposed AEB system must: (a) provide the driver with a forward
collision warning (FCW) at any forward speed greater than 10 km/h (6.2
mph); (b) automatically apply the brakes at any forward speed greater
than 10 km/h (6.2 mph) when a collision with a lead vehicle or a
pedestrian is imminent; (c) prevent the vehicle from contacting the
lead vehicle (i.e., vehicle test device) or pedestrian test device when
tested according to the proposed test procedures; and (d) detect AEB
system malfunctions and notify the driver of any malfunction that
causes the AEB system not to meet the proposed minimum performance
requirements of the safety standard.
3. The NPRM's test procedures evaluate the lead vehicle AEB
performance, PAEB performance, and two scenarios that evaluate
situations where braking is not warranted (i.e., false positives).
Under this proposed requirement, crash avoidance braking is considered
to have occurred when the automatic portion of the brake activation
(excluding any manual braking) exceeds 0.25g.
4. For the lead vehicle AEB performance, the agency proposed three
test scenarios: lead vehicle stopped, lead vehicle decelerating, and
lead vehicle slower-moving. Each lead vehicle scenario is tested at
specific speeds or within specified ranges of speeds to evaluate the
AEB performance with and without applying manual braking to the subject
vehicle.
For the lead vehicle stopped scenario, the agency proposed that the
subject vehicle must perform when no manual braking is used at speeds
ranging from 10 km/h to 80 km/h, and from 70 km/h to 100 km/h when
manual braking is used. The subject (and lead vehicle) speeds proposed
for the decelerating lead vehicle scenario were 50 km/h and 80 km/h
while the proposed range of lead vehicle deceleration was 0.3 g to 0.5
g. Additionally, for the decelerating lead vehicle scenario, the agency
proposed a headway range of 12 m to 40 m for each of the two subject
vehicle speeds. For the slower-moving lead vehicle scenario, a subject
vehicle must perform at speeds ranging from 40 km/h to 80 km/h when no
manual braking
[[Page 39701]]
is used, while a subject vehicle must perform at speeds ranging from 70
km/h to 100 km/h when manual braking is used.
5. For the assessment of PAEB performance, the proposed test
procedures evaluate the subject vehicle in three pre-crash scenarios
involving pedestrians: (a) where the pedestrian crosses the road in
front of the subject vehicle, (b) where the pedestrian walks alongside
the road in the path of the subject vehicle, and (c) where the
pedestrian stands in the roadway in front of the subject vehicle. The
NPRM proposed a specified range of speeds in both daylight and darkness
lighting conditions with lower and upper beam headlamps activated.
6. NHTSA proposed that AEB systems 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 considers a malfunction to include any
condition in which the AEB system fails to meet the proposed
performance requirements. NHTSA proposed that the driver 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.
7. With respect to compliance dates, the NPRM proposed that
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. Vehicles manufactured four years after the publication
date of a final rule would be required to meet all requirements
specified in the final rule. NHTSA proposed that small-volume
manufacturers, final-stage manufacturers, and alterers would be
provided an additional year of lead time for all requirements.
E. Additional Research Conducted in 2023
While past testing conducted in support of the NPRM provided ample
support for the proposed performance requirements, NHTSA conducted
additional research in 2023, which included an evaluation of the newest
vehicles available on the market.\44\ The new research confirmed that
AEB and PAEB performance maintained good performance when compared with
previous testing. This research used three test scenarios to evaluate
the AEB performance of six light vehicles. The vehicles tested included
the 2023 BMW iX, 2023 Ford F-150 Lightning, 2023 Hyundai Ioniq 5
Limited, 2024 Mazda CX-90 Turbo S, 2023 Nissan Pathfinder SL, and the
2023 Toyota Corolla Hybrid XLE. The lead vehicle testing evaluated the
effects of regenerative braking settings for electric (and some hybrid)
vehicles, adaptive cruise control settings, and ambient lighting
conditions on the AEB performance of these vehicles.
---------------------------------------------------------------------------
\44\ NHTSA's 2023 Light Vehicle Automatic Emergency Braking
Research Test Summary and NHTSA's 2023 Light Vehicle Pedestrian
Automatic Emergency Braking Research Test Summary, available in the
docket for this final rule (NHTSA-2023-0021).
---------------------------------------------------------------------------
The lead vehicle scenarios used in this research included the
proposed conditions of lead vehicle stopped, moving, and decelerating.
All conditions and parameters for this research were consistent with
those described in the proposed rule. For nominal testing (tests not
designed to investigate a particular condition or parameter) the Toyota
used in this research avoided contacting the vehicle test device at all
speeds tested from 10 km/h to 80 km/h (50 mph) in the lead vehicle
stopped condition. The Mazda avoided contacting the lead vehicle test
device in all lead vehicle stopped conditions up to 60 km/h (37.5 mph).
BILLING CODE 4910-59-P
[[Page 39702]]
[GRAPHIC] [TIFF OMITTED] TR09MY24.015
[[Page 39703]]
The Toyota, BMW, and Hyundai avoided contacting the lead vehicle
test device in the lead vehicle moving scenarios for all speeds tested.
The Mazda contacted the test device in a single trial at 80 km/h (50
mph) while avoiding contact in all other tested conditions including 4
other trials conducted at 80 km/h.
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\45\ SV is short for ``subject vehicle.''
\46\ POV is short for ``principal other vehicle.''
[GRAPHIC] [TIFF OMITTED] TR09MY24.016
For the lead vehicle decelerating scenario, the BMW did not contact
the lead vehicle test device in any tested condition while the Toyota
contacted the test device during three of the five trials performed at
80 km/h. Other vehicles contacted the test device as shown in the table
below.
[[Page 39704]]
[GRAPHIC] [TIFF OMITTED] TR09MY24.017
The agency also studied lead vehicle AEB performance in darkness.
Results from the dark ambient lighting tests are shown in the table
below. The lead vehicle stopped scenario was used for all day/darkness
comparative tests. The results observed during the dark ambient tests
were largely consistent with those produced during the daylight tests.
The dark versus day contact results observed for a given test speed
were identical or nearly identical for the Hyundai, Mazda, Nissan, and
Toyota. Where impacts occurred, the impact speeds were very close.
[[Page 39705]]
[GRAPHIC] [TIFF OMITTED] TR09MY24.018
The agency also studied the effects of regenerative braking
settings for electric and hybrid electric vehicles on the performance
of lead vehicle AEB. Again, the lead vehicle stopped test scenario was
used for this comparison. The
[[Page 39706]]
regenerative braking settings did not have a negative effect on the
performance of the tested AEB systems. As expected, performance under
the highest regenerative braking settings was slightly better that the
lower, or off, settings. However, the effect of regenerative brake
setting on the vehicle's ability to avoid contact with the lead vehicle
test device was dependent on the vehicle tested.
[GRAPHIC] [TIFF OMITTED] TR09MY24.019
[[Page 39707]]
[GRAPHIC] [TIFF OMITTED] TR09MY24.020
The agency also conducted additional PAEB testing. The same
vehicles used for the lead vehicle testing presented above were used to
evaluate their PAEB performance consistent with the proposed rule. The
results of this testing
[[Page 39708]]
are summarized in the table below. The table provides the maximum speed
tested at which the vehicle avoided contacting the pedestrian test
device. Of specific note, one vehicle avoided contacting the pedestrian
test device at all speeds tested. Some vehicles contacted the test
device at 10 km/h but under further testing, demonstrated the ability
to avoid contacting the pedestrian test device at much higher speeds.
Further details of this testing and additional results are available in
the report contained in the docket provided at the beginning of this
final rule.
[GRAPHIC] [TIFF OMITTED] TR09MY24.021
BILLING CODE 4910-59-C
III. Final Rule and Response to Comments
A. Summary of the Final Rule (and Modifications to the NPRM)
With a few notable exceptions, this final rule adopts the
performance requirements from the proposed rule. This rule requires
manufacturers to install AEB systems that meet specific performance
requirements. These performance requirements include the installation
of an AEB system, track testing requirements for avoiding both lead
vehicles and pedestrians, false activations test requirements, and
malfunction indication requirements.
This final rule includes four requirements for AEB systems for both
lead vehicles and pedestrians. First, there is an equipment requirement
that vehicles have an AEB system that provides the driver with an FCW
at any forward speed greater than 10 km/h (6.2 mph) and less than 145
km/h (90.1 mph). The FCW must be presented via auditory and visual
modalities when a collision with a lead vehicle or a pedestrian is
imminent. This final rule includes specifications for the auditory and
visual warning components consistent with those of the proposed rule,
with some modifications to keep the effectiveness of the FCW while
reducing the potential costs associated with this rule for some vehicle
designs. Similarly, this final rule includes an equipment requirement
that light vehicles have an AEB system that applies the brakes
automatically at any forward speed that is greater than 10 km/h (6.2
mph) and less than 145 km/h (90.1 mph) when a collision with a lead
vehicle is imminent, and at any forward speed greater than 10 km/h (6.2
mph) and less than 73 km/h (45.4 mph) when a collision with a
pedestrian is
[[Page 39709]]
imminent. The maximum speed of lead vehicle AEB is modified from the
NPRM, which did not include upper limits on speeds. NHTSA also
clarified that this requirement applies only when environmental
conditions permit.
Second, the AEB system is required to prevent the vehicle from
colliding with the lead vehicle or pedestrian test devices when tested
according to the standard's test procedures. These track test
procedures have defined parameters, including travel speeds up to 100
km/h (62.2 mph), that ensure that AEB systems prevent crashes in a
controlled testing environment. The three scenarios for testing
vehicles with a lead vehicle and four scenarios for testing vehicles
with a pedestrian test device are finalized as proposed. The agency has
finalized pedestrian tests in both daylight and darkness, while testing
using the lead vehicle test device is conducted in daylight only as
proposed.
Third, this final rule includes the two false activation tests,
driving over a steel trench plate and driving between two parked
vehicles, in which the vehicle is not permitted to brake in excess of
specified amounts proposed in the NPRM.
Finally, 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. The system must
continuously detect system malfunctions, including performance
degradation caused solely by sensor obstructions. If the system detects
a malfunction, or if the system adjusts its performance such that it
will not meet the requirements of the finalized standard, the system
must provide the vehicle operator with a telltale notification. This
final rule has also clarified that the purpose of the malfunction
telltale is to provide information about the operational state of the
vehicle. Some commenters understood the NPRM to have required that the
malfunction telltale activate based on information about the vehicle's
surroundings such as low friction road surfaces.
This final rule includes several changes to the NPRM based on the
comments received:
First, NHTSA includes in this final rule an explicit prohibition
against manufacturers installing a control designed for the sole
purpose of deactivating the AEB system but allows for controls that
have the ancillary effect of deactivating the AEB system (such as
deactivating AEB if the driver has activated ``tow mode'' and the
manufacturer has determined that AEB cannot perform safely while
towing).
NHTSA also modifies the FCW visual signal location requirement in
this final rule to increase the specified visual angle from 10 degrees
to 18 degrees in the vertical direction. This change from the NPRM
provides manufacturers with the flexibility to locate the visual
warning signal within the typical area of the upper half of the
instrument panel and closer to the central field of view of the driver.
While the agency continues to believe that an FCW visual warning signal
presented near the central forward-looking region is ideal, it does not
consider a head-up display to be necessary for the presentation of the
FCW visual signal.
In addition, NHTSA modifies in this final rule the range of forward
speeds at which the AEB must operate. The NPRM required FCW and AEB
systems to operate at any forward speed greater than 10 km/h. This
final rule places an upper bound on the requirement that an AEB system
operate of 145 km/h (90.1 mph) for FCW and lead vehicle AEB and 73 km/h
(45.4 mph) for pedestrian AEB. This final rule also clarifies the
environmental conditions under which the AEB system must perform to be
the same environmental conditions specified in the track testing.
NHTSA also makes a minor adjustment in this final rule to the
measurement method used to characterize the radar cross-section for the
pedestrian test devices. It maintains the cross-section boundaries
contained within the proposed rule as incorporated from ISO 19206-
2:2018 but uses parts of the updated measurement method incorporated
from ISO 10206-3:2021. This newer method was proposed for use in
measuring the vehicle test device, while the older measurement method
was proposed for the pedestrian test devices. The newer method provides
for better filtration of noise by using average measurements taken at
three radar heights as opposed to the single measurement height
specified in the older method. This final rule modifies the measurement
methods for the pedestrian test device to match the method used when
characterizing the vehicle test device.
Finally, this final rule makes a few significant changes to the
lead-time and phase-in requirements. Instead of the deadline proposed
under the NPRM, this final rule requires that manufacturers comply with
all provisions of the rule at the end of the 5-year period starting the
first September 1 after this publication. This will provide
manufacturers with more time to meet the requirements of this final
rule, as most vehicles do not currently meet all of the performance
requirements set forth in this final rule and in light of manufacturer
redesign schedules. The added lead time avoids significantly increasing
the costs of the rule by compelling equipment redesigns outside of the
normal production cycle.
As part of this extension of the lead time, the agency has removed
the phase-in approach to the PAEB performance requirements. While the
NPRM proposed the most stringent PAEB requirements be met 4 years after
a final rule (1 year more than all the other requirements), the agency
is finalizing a 5-year lead time for all requirements (eliminating the
phasing in of requirements during the lead time).
B. Application
NHTSA proposed that the new FMVSS No. 127 apply to all passenger
cars and to all multipurpose passenger vehicles, trucks, and buses with
a GVWR of 4,536 kilograms (10,000 pounds) or less. The agency did not
propose that the new FMVSS apply to vehicles with a GVWR over 4,536
kilograms (10,000 pounds) or to include motorcycles or low-speed
vehicles.
Vehicle Body Types
Several commenters requested that NHTSA consider various vehicle
types in the application of the new FMVSS. The Alliance noted that the
agency's analysis focused only on performance for sedan, SUV and
crossover, and pickup vehicles, and did not consider the constraints
associated with the installation of sensors on vehicles with certain
vehicle designs such as sports cars, which may affect system
capabilities based on unique design characteristics and low profile.
FCA noted that the NPRM did not include the low-speed vehicle (LSV)
class and supported their inclusion in this rule, in part based on the
inclusion of LSVs in the most recent modifications to FMVSS No. 111 and
FMVSS No. 141.
While NHTSA acknowledges the Alliance's concerns that mounting
forward-looking sensors on certain vehicle body types, such as sports
cars, may present some challenges, we believe that technology already
present on some existing production vehicles can be adapted to address
the concern. We also believe that 5 years provides adequate lead time
for manufacturers to consider the changes necessary to their models to
implement AEB. We further note that manufacturers are not restricted as
to sensor placement. Existing production vehicles have sensors located
in a variety of places. NHTSA is aware of several vehicles
[[Page 39710]]
equipped with radar and camera sensors mounted in the cabin near the
rearview mirror. Such a sensor configuration would avoid the
installation constraints imposed by small bumpers, avoid placement
behind carbon fiber material, and accommodate placement further above
the ground.
Regarding FCA's comment, LSVs were excluded from the scope of the
final rule for several reasons. First, there are no LSVs on the market
that NHTSA is aware of that are currently equipped with AEB or PAEB.
This means that NHTSA was not able to procure a vehicle for testing or
otherwise evaluate how a LSV would perform if equipped with AEB/PAEB.
Second, there is a lack of specific safety data to support an argument
that LSVs should be equipped with AEB/PAEB. NHTSA does not want to
preclude such vehicles from being equipped with these safety systems,
but the current safety data does not provide justification for
including them in this rule. Finally, and as discussed in the FRIA,
LSVs were not included due to uncertainty about the feasibility and
practicability of AEB for those vehicles. Although LSVs were included
in the two most recent standard of significance (FMVSS 111 Backup
Camera and FMVSS 141 Sound for Electric Vehicles) without
practicability concerns, we note that those standards include
requirements that provide aids to assist the driver or alerts the
driver. In such cases, those features do not require the vehicle to
react but instead elicit a driver reaction. As these vehicles were not
included in the testing conducted by the agency, our analysis is unable
to characterize the performance of AEB on these vehicles. Therefore, in
the absence of any data to characterize how these systems may perform
on LSVs, they were not included in the final rule.
Heavier Vehicles
The Alliance and FCA commented about the interaction between the
proposed standard and FMVSS Nos. 105 and 135, which regulate braking.
The Alliance recommended a comprehensive review of the impact of the
proposed rule with appropriate accommodations to exclude or include a
cap on the applicability of the proposal based on vehicle weight. The
Alliance stated that typical electronic stability control (ESC) systems
may not provide the fluid flow rates needed to produce the braking
performance necessary to meet the proposed rule. FCA noted that the
proposed standard applies to vehicles between 7,716 pounds GVWR (the
upper limit for FMVSS No. 135 application) and 10,000 pounds GVWR,
opining that this proposed standard is not intended to force changes in
the underlying braking performance of vehicles in that range and noting
that testing has not been conducted on vehicles over 7,000 pounds GVWR.
FCA suggested limiting application of proposed FMVSS No. 127 to
vehicles under 7,716 pounds GVWR.
NHTSA evaluated compliance test results for FMVSS No. 135 conducted
over the last several years. There were 30 vehicles included in this
testing, including small sedans, large pickup trucks, minivans, SUVs
and other vehicle types to which this new FMVSS would apply. The
results indicate that the braking performance of nearly all vehicles
was much better than what FMVSS No. 135 requires and the average
deceleration for the larger pickup trucks also outperformed some of the
smaller sedans, SUVs, and minivans. These test results indicate that
braking performance is more than sufficient to permit compliance with
this final rule without a need for braking changes or supplements.
While this rule is not intended to force changes in the underlying
braking performance of vehicles, the commenters stopped short of
asserting that braking improvements would be necessary, stating only
that improvements may be necessary. Moreover, even if underlying
braking performance improvements were necessary, nothing in the
comments suggests that there are any technical barriers or any other
impediments that would make such improvements infeasible.
Automated Driving Systems
Several commenters suggested exempting vehicles with automated
driving systems from the application of some or all of the proposed
FMVSS No. 127. Volkswagen recommended exempting autonomous vehicles
(AVs) from the parts of the regulation that involve displaying warnings
and the parts for which manipulation of manual controls is part of the
test procedure. Similarly, AVIA requested that the forward collision
warning requirements not apply to AVs.
Zoox requested that the proposed FMVSS not apply to AVs. Zoox
viewed the proposed rule as directed toward human drivers, and that
applying it to AVs may result in unintended consequences, such as
establishing emergency collision avoidance standards for AVs without
considering other avoidance tools available to AVs, thereby
constraining their safety capabilities.
AVIA also provided suggested changes to the proposed application
language that would exclude vehicles equipped with ADS from the
requirement to have an AEB system if the ADS meets the performance
requirements of the proposed standard. The Alliance commented that ADS-
equipped vehicles without manual controls should be exempt from the
driver warning and DBS requirements, which it viewed as relevant only
when there is a human driver and similarly that the DBS requirements
should be applicable only if a brake pedal is installed or required to
be installed in the vehicle.
NHTSA expects that ADS-equipped vehicles are capable of meeting the
performance requirements of this rule, especially those related to
identifying crash imminent situations with vehicles and pedestrians and
applying the brakes to avoid contact. Volkswagen is correct that NHTSA
is considering how to address telltales, alerts, and warnings, like
FCW, in the context of vehicles driven by ADS.\47\ While NHTSA
continues to engage in research to support the related rulemakings
evaluating the application of existing FMVSS to ADS-equipped vehicles,
NHTSA is finalizing this rule for all light vehicles and will consider
future modifications regarding telltales, alerts, and warnings, as well
as crash avoidance standards, generally, for ADS-equipped vehicles as
needed under separate rulemaking efforts.\48\
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\47\ See <a href="https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202304&RIN=2127-AM07">https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202304&RIN=2127-AM07</a>.
\48\ See <a href="https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202304&RIN=2127-AM00">https://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202304&RIN=2127-AM00</a>.
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C. Definitions
The proposed rule contained key definitions to facilitate the
understanding of the rule. While there were 15 proposed definitions
included in section S4 of the proposed new FMVSS, this section focuses
on those raised in comments.
AEB System
The NPRM defined an automatic emergency braking system 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. Several
commenters recommended changes to the definition of AEB system:
Bosch asked NHTSA to consider adopting the definition of ``Advanced
Emergency Braking System (AEBS)'' used in United Nations Regulation No.
152 (UNECE R152) to promote global harmonization and enhance clarity in
[[Page 39711]]
the terminology used across various jurisdictions.
Porsche and Volkswagen stated that the AEB system requirements
throughout the NPRM require performance metrics specific to mitigating
collisions with lead vehicles and pedestrians, generally not mitigating
collisions with objects, but the proposed definition for AEB includes
reference to ``objects'' and ``road users.'' Specifically, Porsche
referred to the requirements that the vehicle is required not to apply
braking when encountering a steel trench plate. Porsche expressed
concern that, by including ``object,'' the AEB definition could
introduce confusion in whether braking could be applied in false
activation tests. Volkswagen noted that the trench plate could be
categorized as an ``object.'' Bosch commented that the broad definition
poses challenges in requiring that there is no collision with any
``object.''
In reference to the term ``road users,'' Porsche and Volkswagen
commented that the NPRM referenced pedestrians and was not more broadly
inclusive of other road-users such as bicyclists. Both recommended
replacing the term ``road user'' with ``pedestrian'' to align with the
proposed requirements. Bosch did not specifically address the term
``road users,'' but recommended that NHTSA replace ``object'' with
``pedestrian'' in the proposal for more clarity and consistency in the
context of the FCW and AEB system.
An anonymous commenter stated that the AEB system definition does
not specify what constitutes a ``crash imminent situation'' or how the
system determines if the driver has not applied the brakes, or how much
braking force is applied to the system. This commenter noted that these
are important details that may affect the performance and effectiveness
of the AEB system.
BIL 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. Consistent with this definition, NHTSA defines an AEB system
as one that detects an imminent collision with a vehicle or with an
object. However, nothing in the definition of AEB system requires
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.
The agency has reviewed the various definitions used in the NPRM to
assess whether meaningful harmonization could be achieved with UNECE
regulations. In UNECE Regulation No. 152, ``Advanced Emergency Braking
System (AEBS)'' means a system which can automatically detect an
imminent forward collision and activates the vehicle braking system to
decelerate the vehicle with the purpose of avoiding or mitigating a
collision. The definition proposed in the NPRM is functionally very
similar, but uses language from BIL. Unlike UNECE Regulation No. 152,
NHTSA's definition also provides a level of clarity as to where the
detection of vehicles, objects, and road users must occur, that is ``in
or near the path of a vehicle.''
The commenters' concern that this definition requires detection of
and reaction to ``all objects'' is unfounded. NHTSA has also considered
the use of the term ``road users'' in the AEB definition. NHTSA is
aware of manufacturers that have designed AEB systems to detect
pedestrians. However, the performance requirements make clear that this
final rule requires detection and reaction to pedestrians and lead
vehicles. The use of ``objects'' and ``road users'' merely identify
potential hazards on a road that may require emergency braking, but are
not intended to impose requirements beyond the requirements set forth
in the standard.
The agency considered comments seeking inclusion of various
performance requirements in the definitions section. Those comments did
not explain why such a change is necessary. As a general matter of
regulatory structure, NHTSA limits the definition section to defining
terms; the operative regulatory text is the appropriate location for
performance requirements and other directives of substantive effect.
Therefore, NHTSA adopts the proposed definition of AEB, which is
defined 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.
Forward Collision Warning
The NPRM defined forward collision warning as 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.
Consistent with its comment about alignment of the definition of
AEB with UNECE R152, Bosch recommended that NHTSA adopt UNECE R152's
Collision Warning definition for the FCW definition: ``a warning
emitted by the [Advanced Emergency Brake System] AEBS to the driver
when the AEBS has detected a potential forward collision.''
NHTSA has finalized the definition of FCW as an auditory and visual
warning provided to the vehicle operator by the AEB system that is
designed to induce immediate forward crash avoidance. This definition
provides clarity that both an auditory and visual warning are necessary
for a complete warning that is most likely to reengage a distracted
driver. For purposes of the test procedure established in this final
rule, if only the visual or only the auditory component of the FCW is
provided, then the FCW onset has not happened, and the test procedure
steps will not take place until both the auditor and visual components
are both in place. As such, the UNECE R152 definition suggested by the
commenters does not provide this needed clarity.
Zoox also recommended changes to the FCW definition to clarify
applicability to conventional vehicles with human drivers only. As
noted above, NHTSA is finalizing this rule for all light vehicles and
will consider future modifications regarding telltales, alerts, and
warnings, as well as crash avoidance standards, generally, for ADS-
equipped vehicles as needed under separate rulemaking efforts. Because
NHTSA is not adjusting requirements to accommodate ADS, no definition
changes are required to address this issue.
Onset
Commenters requested clarification or addition to the definitions
to further clarify the proposed requirements and test procedures. The
NPRM defined ``forward collision warning onset'' as the first moment in
time when a forward collision warning is provided. Automotive Safety
Council sought clarification whether this would be measured in terms of
a signal output on the Controller Area Network (CAN) bus, or measured
by sound physically emitted from the speaker. NHTSA clarifies that FCW
onset would be determined via measurement of the FCW auditory signal
sound output within the vehicle cabin and the illumination of the FCW
visual signal. CAN bus information would not be used to assess FCW
onset.
The NPRM did not provide a definition of braking onset. Humanetics
stated that the term ``vehicle braking onset'' needed further
clarification in all test protocols. Humanetics suggested a target
value of speed change or deceleration value should be used as an
indicator of the time of braking onset.
[[Page 39712]]
NHTSA has decided to clarify the term ``vehicle braking onset'' in
the regulation text as Humanetics suggested, by defining the ``subject
vehicle braking onset'' as the point at which the subject vehicle
achieves a deceleration of 0.15g due to the automatic control of the
service brakes. To ensure clarity in the PAEB test procedure, NHTSA has
used the term ``subject vehicle braking onset'' to clarify that NHTSA
is referring to the vehicle braking onset of the subject vehicle. The
0.15g deceleration was adopted based on the agency's experience
conducting AEB testing as this value has proven a reliable marker for
PAEB onset during track testing.\49\
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\49\ <a href="https://www.regulations.gov/document/NHTSA-2021-0002-0002">https://www.regulations.gov/document/NHTSA-2021-0002-0002</a>.
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Other Definitions
NHTSA does not believe that any further additional definitions are
necessary for manufacturers to understand the performance requirements
of the standard or their obligations. NHTSA believes that terms
appearing within the proposed definitions are sufficiently clear from
the context of the regulation. For example, we believe the meaning of
``crash imminent situation'' is discernable from close review of the
performance requirements, including the test procedures; from these,
the commenter can determine what the agency would consider crash
imminent for the set of testable ranges included in this rule.
Finally, NHTSA acknowledges Consumer Reports' and AAA's requests to
limit the use of the terms CIB and DBS. NHTSA has already done this by
excluding those terms from the regulatory text. While NHTSA used CIB
and DBS throughout the preamble to the NPRM and in this final rule, it
is doing so because these terms are frequently used by industry, and
their use in the preamble helps readers understand what NHTSA is
saying, particularly in the context of prior research and NCAP, which
use those terms.
D. FCW and AEB Equipment Requirements
NHTSA proposed that an FCW must provide the driver warning of an
impending collision when the vehicle is traveling at a forward speed
greater than 10 km/h (6.2 mph). Similarly, the NPRM require a vehicle
to have an AEB system that applies the service brakes automatically
when a collision with a lead vehicle or pedestrian is imminent at any
forward speed greater than 10 km/h (6.2 mph). NHTSA stated in the NPRM
that this minimum speed should not be construed to prevent a
manufacturer from designing an AEB system that activates at speeds
below 10 km/h (6.2 mph).
This proposed requirement was described as an equipment requirement
with no associated performance test. No specific speed reduction or
crash avoidance would be required. However, this requirement was
included to ensure that AEB systems are able to function at all times,
including at speeds above those NHTSA proposed as part of the
performance test requirements where on-track testing is currently not
practicable. NHTSA received comments regarding both the minimum
required activation speed and the lack of maximum activation speed.
1. Minimum Activation Speed
Comments
MEMA supported not having FCW and AEB performance requirements at a
speed below 10 km/h (6 mph), opining that AEB systems do not offer
consistent performance at such low speeds.
Bosch and Volkswagen suggested changing the FCW minimum activation
speed to 30 km/h. Bosch believed that FCW may not be beneficial at
lower speeds because the AEB system proves to be a sufficient solution.
Bosch stated that at lower velocities no driver reaction is required
because the AEB intervention can fully avoid the collision after the
``last time to steer'' has already occurred. According to Bosch, as the
vehicle speed increases, from 30 km/h upwards, the last point to steer
gradually moves to a point after the last point to brake. In effect, a
driver warning then becomes beneficial, and FCW can help the driver
take appropriate action to avoid or mitigate a collision.
Volkswagen stated that setting a requirement for FCW at low speeds
can lead to high false positive rates. Volkswagen also noted that
meeting the proposed performance requirements depended on the FCW being
issued before the activation of AEB, and could lead to very sensitive
system behavior, especially for PAEB. Volkswagen suggested increasing
the minimum FCW activation speed to 30 km/h, but suggested it would
still be acceptable to display the FCW symbol simultaneously with AEB
activation at speeds below 30 km/h to make the driver aware of the
event that just occurred.
The Center for Auto Safety disagreed with the 10 km/h minimum speed
threshold saying that it was not clear why it was selected. The Center
for Auto Safety commented that PAEB should be activated as soon as the
vehicle is shifted into gear to avoid injurious or fatal rollovers of
children and other hazards. Consumer Reports commented that it
understood the technical reasons for the proposed minimum speed of 10
km/h (6.2 mph), but expressed concern that such a lower speed bound
would fail to address the issue of what it described as ``frontover''
incidents.\50\ Consumer Reports said there had been an increase in
``frontover'' incidents since 2016, and that it believed that the
increasing market share of larger vehicles with increased blind zones
was correlated with this increase.
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\50\ There is not yet a finalized definition of ``frontover''
that is used within NHTSA or outside of NHTSA, and NHTSA is
currently researching how this crash type should be defined. As
NHTSA previously indicated, until more data is gathered via the Non-
Traffic Surveillance (NTS) system, actual frontover crash counts are
difficult to confirm due to the challenges law enforcement faces in
distinguishing these crashes from other forward moving vehicle
impacts with non-motorists and to the locations where these crashes
often occur. For example, a forward moving vehicle crash involving a
driver turning into a driveway and striking a child playing in the
driveway would typically not be considered a frontover; but if that
driver struck the child while pulling out of a garage (having backed
into the garage), it would be considered a frontover. These nuances
pose difficulties for law enforcement to accurately capture
frontover incidents which, in turn, complicates our data collection.
Additionally, frontover crashes frequently occur in driveways and
parking lots that are not located on the public trafficway; thus,
law enforcement may not report these occurrences using a crash
report.
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Agency Response
NHTSA is finalizing a minimum activation speed of 10 km/h as
proposed. The agency considered increasing this minimum to 30 km/h, as
suggested by some commenters, to avoid unwanted and unnecessary alert
at low speeds. However, after considering the potential impacts of such
a modification, particularly the safety of pedestrians, the agency is
finalizing the minimum activation speed as proposed for the forward
collision warning. This 10 km/h minimum threshold is also harmonized
with UNECE Regulation No. 152. Furthermore, as stated in the NPRM, 6 of
11 manufacturers whose owner's manuals NHTSA reviewed indicated that
their AEB system have a minimum speed below 10 km/h. NHTSA is
encouraged that manufacturers are choosing to have lower speed
thresholds for AEB functionality.
As for frontover crashes, NHTSA agrees with Consumer Reports about
the importance of understanding driver visibility and about the need to
reduce such crashes. Additional research is needed to develop accurate
and rigorous methods of evaluating direct visibility
[[Page 39713]]
from the driver's seat. Research is also needed to better understand
the safety problem and the scenarios associated with forward blind
zones and frontover crashes. Beginning in January 2023, two new non-
traffic crash data elements related to backovers \51\ and frontovers
were added to the agency's Non-Traffic Surveillance System, which will
enhance evaluation of the scope and factors associated with frontover
crashes.
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\51\ NHTSA has previously defined backover crashes as crashes
where non-occupants of vehicles (such as pedestrians or cyclists)
are struck by vehicles moving in reverse. See <a href="https://www.federalregister.gov/documents/2014/04/07/2014-07469/federal-motor-vehicle-safety-standards-rear-visibility">https://www.federalregister.gov/documents/2014/04/07/2014-07469/federal-motor-vehicle-safety-standards-rear-visibility</a>.
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2. Maximum Activation Speed
Comments
The National Transportation Safety Board (NTSB) supported the
proposed requirements for FCW, specifically pertaining to the necessity
of the warning at all speeds above 10 km/h, but the NTSB stated that
FCW activation must never delay AEB engagement. NTSB stated that its
support was rooted in several NTSB investigations of vehicles operating
in partial automation mode at the time of the crash.
In contrast, many commenters raised substantial concerns about the
proposed NPRM requirement that FCW and AEB function, at least at some
level, at all speeds and under all environmental conditions. Among
these concerns was that the requirement would not meet various aspects
of the Safety Act.
The Alliance disagreed with the agency setting undefined
performance requirements that are not stated in objective terms
consistent with 49 U.S.C. 30111 and urged NHTSA to provide
clarification when issuing a final rule that compliance verification
will be measured only by defined test procedures that meet established
criteria for rulemaking. It objected to what it viewed as undefined
performance requirements without a clearly demonstrated safety need
that create significant challenges from a product development
perspective, making it unclear whether or how NHTSA might seek to
verify compliance. Without defined and objective criteria, the Alliance
thought that policy uncertainty would create ambiguity about potential
enforcement actions as there would be no clear parameters to reliably
measure performance.
The Alliance suggested that a defined upper bound or maximum
operational speed for the AEB/PAEB system was needed due to the
possible unstable vehicle dynamics that could result from hard braking
at very high speeds. Furthermore, the Alliance opposed open-ended
performance requirements through regulation without objective test
procedures, noting that it becomes increasingly more challenging to
provide significant levels of speed reductions at higher speeds, and it
viewed the expectation that manufacturers are capable of providing
undefined levels of avoidance at all speeds as neither practicable nor
reasonable. According to the Alliance, requirements that exceed the
current speed ranges must be supported by relevant data to support
practicability and must include defined and objective test procedures.
The Alliance noted that the complexity of designing systems capable of
going beyond what the agency proposes to test would likely result in
significant development costs that are not accounted for in the
agency's cost-benefit analysis and that would add unnecessary costs for
consumers, while diverting research and development efforts from other
priority areas that may yield greater improvements in vehicle safety.
Multiple automakers expressed similar concerns, some recommending
that NHTSA limit AEB activation to maximum speeds and several
specifying suggested upper bounds. For example, Honda suggested that
NHTSA limit AEB activation to when the vehicle is traveling at maximum
135 km/h (84 mph) when approaching a lead vehicle traveling at maximum
75 km/h (47 mph) and limit pedestrian AEB activation to when the
vehicle is traveling at maximum 88 km/h (55 mph). Porsche suggested
that for the lead vehicle, DBS apply to speeds above 100 km/h (62 mph)
and for pedestrians to speeds above 65 km/h (40 mph), and that crash
imminent braking (CIB) be required to operate between 10 km/h (6 mph)
and 100 km/h (62 mph) for lead vehicle and between 10 km/h (6 mph) and
65 km/h (40 mph) for pedestrian. Porsche also provided suggested
regulatory text.\52\
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\52\ <a href="https://www.regulations.gov/comment/NHTSA-2023-0021-0868">https://www.regulations.gov/comment/NHTSA-2023-0021-0868</a>.
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NTSB expressed similar concerns about the need for testing, stating
that without a dedicated test protocol or an explicit statement about
the extent of operational functionality, broader capabilities (above
the testing requirements) remain only presumed and not necessarily
expected. NTSB encouraged NHTSA to clarify its intent and expectations
for system performance in scenarios and conditions outside the proposed
test-track compliance testing by considering additional testing or
other compliance tools to examine the performance of AEB systems under
other real-world conditions, and particularly whether the operational
functionality would extend to non-tested hazards such as traffic safety
hardware, bicyclists and motorcyclists, and vehicles with untested
profiles or at varying angles and offsets.
Commenters raised potential technical challenges to effective
implementation of the proposed requirement. For example, Honda was
concerned about AEB and radar sensor limitations when operating at high
speeds--mainly the complex interdependency between speed and the
distance and accuracy at which objects must be detected to be avoided
(or even to mitigate a crash). Honda noted that higher speeds mean that
objects will need to be detected at greater distances, and at greater
distances there is less image resolution, greater positional error, and
greater impact from things like roadway geometry. Honda and Porsche
stated that requiring braking to occur at unrestricted high speeds
leads to misidentification of objects and increases false positive
activations.
Honda further asserted that camera resolution is limited by the
pixel count on the image capture chip and that at longer distances, the
number of pixels for an object will be reduced, resulting in blur that
makes it difficult to detect objects (the blur can be further
exacerbated by the designed focal length of the lens). Further, Honda
stated that a higher resolution can be achieved only through new sensor
hardware that would require further developmental work as well as more
processing power, including a change of imaging processing electronic
control unit (ECU). Honda stated that for camera-radar fusion systems,
small errors in the fusion algorithm are amplified at higher speeds
(due to the longer distances) and could compromise the system's
performance. Additionally, according to Honda, these reductions in
sensor accuracy significantly increase the risk of misidentification of
potential objects and may lead to excessive false positive activations,
potentially creating negative safety consequences. This could include
situations where the system mistakenly recognizes the same lane as the
adjacent lane or roadway objects as other vehicles.
Other commenters also raised concerns about the potential for false
activations caused by the need for AEB to operate at very high speeds.
For example, Volkswagen commented that false activation becomes more of
a risk as speeds increase, and that these risks
[[Page 39714]]
are not controllable, as defined in ISO 26262.
Commenters raised concerns about whether braking was the most
appropriate avoidance maneuver in high-speed scenarios. Honda was
concerned that AEB activation might interfere with other technologies
such as the Automatic Emergency Steering. Mitsubishi, and Toyota echoed
the Alliance's concern that in some situations AEB activation while
traveling at high speed may induce unstable vehicle dynamics.
Mitsubishi stated that these situations may occur due to unfavorable
interactions with road surface conditions, road curvature, or for other
unpredictable reasons. Mitsubishi thought that such activation could
also lead to unexpected outcomes for a vehicle following the subject
vehicle.
Rivian stated that if post-crash review is used to assess
compliance, it may introduce a number of uncontrollable or subjective
variables into the compliance evaluation. Rivian opined that post-crash
review would necessarily involve evaluation of a motor vehicle that is
no longer a new motor vehicle and that may have been modified or
altered in a manner to affect the AEB performance. It further noted
that varying environment or roadway conditions could also impact the
AEB performance and, without a proper comparison using reference test
equipment, it would be difficult to identify discrepancies between the
expected AEB results and the actual results, limiting the technical
effectiveness of a post-crash review.
Commenters suggested a number of different solutions to resolve
their concerns. Most requested that the all-speeds requirement be
removed. Alternatively, Honda and others (as noted earlier) asked that
NHTSA establish a maximum speed at which AEB detection performance is
assessed according to an established test procedure. Volkswagen asked
that NHTSA exclude activation against vulnerable road users at high
speeds, believing it would decrease false positive rates significantly.
Volkswagen thought this could be justified as pedestrians would not be
expected on the roads with these higher speeds.
Agency Response
Authority Under the Safety Act
Various commenters asserted that performance requirements without
objective test criteria were inconsistent with the Safety Act's
requirements for objectivity and practicability. NHTSA believes that
these assertions reflect a misunderstanding of the proposal.
Essentially, NHTSA proposed specific performance requirements for AEB
within a defined range of speeds (accompanied by specific testing
procedures) and, separately, an equipment requirement--i.e., a
requirement for a functioning vehicle AEB system. The proposed
requirement for a functioning AEB system at all speeds was an equipment
requirement, not a performance requirement. Case law supports that
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.\53\ Testing at high speeds is not practical due to
the dynamics of such testing and testing equipment limitations. As
detailed in the NPRM, the testing requirement upper speeds are based on
the capability to safely and repeatably conduct testing. The testing
devices can only be driven, and can only tolerate impacts, up to
certain speeds. These edge speeds are the main limiting factor for the
upper bound of the testing speeds, as testing above those speeds would
be impractical. NHTSA has previously specified an equipment requirement
without an accompanying test procedure. For example, under FMVSS No.
126, NHTSA issued an equipment requirement for understeer and explained
why a performance test for understeer was too cumbersome for the agency
and the regulated community.\54\ In the final rule for FMVSS No. 126,
NHTSA stated that historically, ``the agency has striven to set motor
vehicle safety standards that are as performance-based as possible, but
we have interpreted our mandate as permitting the adoption of more
specific regulatory requirements when such action is in the interest of
safety.'' \55\
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\53\ Chrysler Corp. v. Dep't of Transp., OT, 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).
\54\ 72 FR 17236 (Apr. 6, 2007).
\55\ Id. at 17299.
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There are other FMVSS that contain equipment requirements,
sometimes in addition to performance requirements. FMVSS No. 111 has
several requirements that are equipment requirements. S5.1 of FMVSS No.
111 requires that each passenger car be equipped with an inside
rearview mirror of unit magnification, which is the equipment
requirement without an associated test procedure. S5.3 requires that
any vehicle that has an inside rearview mirror that does not meet the
performance requirements for field of view included in S5.1.1 must also
have an outside rearview mirror meeting certain performance
requirements. FMVSS No. 135 requires that the service brakes shall be
activated by means of foot control. This is an equipment requirement in
an FMVSS that also has performance requirements. S5.1 of FMVSS No. 224,
``Rear impact protection,'' requires trailers and semitrailers with a
GVWR of 4,536 kg or more to be equipped with a rear impact guard
certified as meeting FMVSS No. 223, ``Rear impact guards.''
Technical Concerns
Various commenters raised concerns about technical limitations that
might create challenges for AEB systems at high speeds, such as sensor
limitations, false activations, and whether hard braking was an
appropriate response at higher speeds.
NHTSA is aware, from a review of owner's manuals, that many
manufacturers have equipped their vehicles with AEB systems that
activate at speeds higher than the testable ranges NHTSA proposed. As
an example, the 2022 Toyota Prius Prime owner's manual informs vehicle
owners that the maximum AEB activation speed for its system is 180 km/h
(112 mph). Other examples include: the 2023 Hyundai Palisade lists the
maximum AEB activation speed as 200 km/h (124.27 mph), the 2018 Tesla
Model 3 Dual Motor lists the maximum AEB activation speed as 150 km/h
(93.2 mph), the 2021 Volvo S60 lists the maximum AEB activation speeds
as 115 km/h (71.4 mph), the 2021 Ford Bronco lists the maximum AEB
activation speed as 120 km/h (74.5 mph), and the 2022 Lexus NX 250
lists a maximum AEB activation speed of 180 km/h (111.8 mph). This
demonstrates that it is common practice for AEB systems to function
above the testable range of speeds.
The agency considered comments asserting that higher travel speeds
require longer sensing ranges. However, the equipment requirement does
not specify a particular speed reduction or level of avoidance. The
agency considered the kinematics for an AEB system installed on a
vehicle that meets the track test requirements at 80 km/h without
manual braking. For a vehicle with automatic initiated deceleration
capabilities of 0.7g, in a lead vehicle stopped situation, the brakes
must be applied at a distance of approximately 37 m (equates to a time-
to-collision of 1.66 s). In such a situation, the vehicle's sensor
range would need to demonstrate capabilities at a distance of at least
37 m. In a similar rear end collision situation with the vehicle
traveling at 145 km/h and an identical detection
[[Page 39715]]
range of 37 m, the time-to-collision would be only 0.91 s. If the
vehicle applied the same 0.7g deceleration at the same 37 m distance, a
collision would not be avoided. A theoretical collision would occur
with the vehicle impacting the stopped vehicle at 119 km/h (74 mph).
However, the vehicle would have an AEB system that applied the brakes
when a crash is imminent, as the proposal would require.
Requiring that the AEB system function at higher speeds has
significant safety benefits. According to the injury risk curve used in
the FRIA available in this docket, the probability of a fatality
occurring in a rear-end collision where the striking vehicle is
impacting at 90 mph is almost 20 percent. That probability is reduced
to 6.8 percent for a travel speed of 74 mph. That reduction in fatality
risk is afforded with little to no additional sensing system
capabilities beyond what is required to satisfy the track tested
requirements. In other words, if the AEB system activates at 90 mph and
slows the vehicle down by just 16 mph, the risk of a fatality declines
significantly. If the system were deactivated at speeds above the test
procedure limit of 62 mph, many more fatalities would occur than if the
system is activated and functioning with the capabilities required to
satisfy the track tested requirements. Beyond 145 km/h (90.1 mph),
however, the expected safety benefits are greatly diminished, primarily
because very high travel speeds are relatively uncommon and currently
above legal operating speeds in the U.S.
NHTSA does recognize that pedestrian crash interactions are much
less straightforward kinematically than a lead vehicle rear-end crash
interaction. This is because the pedestrian may be moving in any number
of directions in front of the vehicle, including suddenly darting in
front of a vehicle, making detection and mitigation more challenging as
speed increases. In such situations, the agency agrees with commenters
that it is not practical to require an alert and braking at speeds
greatly above those for which the track test applies. For this reason,
this final rule reduces the speed range for pedestrian detection
functionality to any speed greater than 10 km/h (6.2 mph) and less than
73 km/h (45.4 mph). Similarly, for pedestrian AEB functionality, this
final rule reduces the upper end speed for which alerts and braking are
required to 73 km/h (45.4 mph). This speed range balances
practicability and safety.
Post-Crash Review
As for Rivian's comment on post-crash review, NHTSA can determine
compliance with this equipment requirement through visual observation
and other information, if requested from the manufacturer. Post-crash
review is an important tool to the agency. NHTSA acknowledges Rivian's
discomfort with post-crash review being considered as a primary tool
for compliance purposes, but NHTSA does not believe post-crash review
will be necessary to enforce this requirement. Instead, NHTSA believes
it can rely on visual observation, manufacturer test results used as a
basis for certification, and other information to determine whether a
vehicle meets this equipment requirement.
Conclusion
After careful consideration and in response to commenters stating
that there was not a safety need justifying the lack of a maximum speed
cap on this equipment requirement, NHTSA has decided to modify the
proposed requirement. The agency recognizes that while vehicles are
capable of very high speeds, the current maximum speed limit in the
United States is 85 mph. With this in mind and in response to comments
urging a speed cap for AEB operation, NHTSA decided to require that AEB
systems operate (i.e., warn the driver and apply the brakes) at speeds
up to 145 km/h (90.1 mph) for lead vehicle detection and 73 km/h (45.4
mph--based on the overall complexity of detecting and differentiating
between an imminent pedestrian crash and a pedestrian encounter that is
unlikely to result in a crash, such as when a pedestrian is located on
the sidewalk) for pedestrian detection. NHTSA also believes that
adopting this speed cap is consistent with the agency's analysis of the
safety problem and with NHTSA's goals of resolving as much of the
safety problems as possible.
NHTSA believes this requirement is feasible, particularly in light
of the absence of any performance requirements (for example, that a
vehicle brake automatically to avoid contact) other than at the speeds
tested in the performance requirements specified in this standard. This
final rule simply requires that an AEB system function to warn and
apply the brakes at speeds up to 145 km/h (90.1 mph) for FCW and lead
vehicle AEB. The agency is not preventing manufacturers from having FCW
activate at speeds above 145 km/h (90.1 mph). NHTSA is aware from
recent research into owner's manuals that many AEB systems operate at
speeds above the testable range, and NHTSA wants to ensure that
manufacturers have the flexibility to provide FCW (and AEB) at speeds
above those included in this final rule. This maximum required
activation speed addresses the concerns raised by commenters about a
requirement without an upper bound.
3. Environmental Conditions
In the NPRM, NHTSA explained that this equipment requirement was
intended to complement the performance requirements by, among other
things, ensuring that AEB systems continue to function in all
environments, not just the test track environment. Unlike track
testing, real world traffic scenarios may involve additional vehicles,
pedestrians, bicyclists, buildings, and other objects within the view
of the sensors and should not negatively affect their operation.
NHTSA received several comments expressing concern about the
unspecified environmental conditions included in the NPRM.
NHTSA is committed to establishing performance requirements that
are as reflective of the real world as possible, and that encourage
manufacturers to develop robust AEB systems with sufficient resiliency
to handle the widely variable scenarios they are intended to handle. In
general, NHTSA is concerned that high system brittleness will not
provide the maximum safety benefits and could be confusing to the
public because of expectations about how AEB systems should work. The
language of the NPRM sought to provide safety under environmental
conditions outside of those specified in a track testing environment.
That said, NHTSA agrees with commenters that the expectation that
the AEB system work in unspecified environments should be clarified for
manufacturers to certify that their vehicles will meet the equipment
requirement established by this final rule. There are environmental
conditions that may preclude the safe application of automatic braking,
and to a lesser extent warnings. However, the complexity of conditions
and combination of conditional factors make it difficult to clearly
enumerate those conditions. Therefore, this final rule now clearly
specifies the conditions in which the systems are expected to perform
to meet the equipment requirement are those conditions specified for
testing the performance requirements. Notwithstanding this specificity,
NHTSA encourages manufacturers to continue working
[[Page 39716]]
toward delivering AEB systems that are robust and that function in as
many real-world environments as possible.
The Utah Public Lands Alliance commented that the proposed rule did
not take into account the complexities of off-road environments, such
as obstacles, mud, rocks, and varying slopes, which may render the AEB
less effective or even cause false alarms, disrupting the driving
experience. NHTSA notes that the final rule does not include off-road
environments as a required aspect of AEB performance because the
agency's authority under the Safety Act focuses on the on-road
environment.
E. AEB System Requirements (Applies to Lead Vehicle and Pedestrian)
1. Forward Collision Warning Requirements
Because the window of time that FCW affords a driver in a crash-
imminent situation is small, the proposed warning characteristics were
intended to facilitate quick direction of the driver's attention to the
roadway in front of them and to compel the driver to apply the brakes
assertively. The FCW criteria proposed were based on many years of
warning research and vehicle crash avoidance research conducted by
NHTSA and others as described in the NPRM. The criteria seek to achieve
an effective warning strategy that is consistent across vehicle models
and proven by research to promote the highest likelihood of drivers
quickly understanding the situation and responding efficiently to avoid
a crash.
Comments
Commenters generally supported a requirement for an FCW to be
presented for lead vehicle and pedestrian scenarios. However, a
majority of commenters preferred more flexibility of FCW implementation
than is afforded by the requirements, as summarized below.
Multiple commenters were opposed to the degree of specificity
included in the proposed FCW requirements. These commenters thought
that the state of varied implementation of FCW that exists currently
was sufficient. For example, Volkswagen opined that the regulation
``should specify the warning modes (visual, auditory, optionally
haptic), but leave the implementation up to the manufacturer if the
warning is easily perceivable and visually distinguishable from other
warnings.'' Volkswagen thought that variation in FCW strategy across
manufacturers would not be a problem since manufacturers ``explain
their warning strategy in their owner's manuals.'' Similarly, the
Alliance contended that U.S. customers may be ``already familiar with
the ISO symbol and flashing alert'' and that it ``would be beneficial
to safety'' for NHTSA to allow flexibility for manufacturers to select
the visual warnings deemed to be most effective in the context of the
overall vehicle HMI.
IIHS cited its own research as a basis for contending that the
proposed FCW ``design requirements are unnecessarily overly
prescriptive'' given that ``existing industry practices for FCW are not
only effective for preventing crashes but are also acceptable and
understandable to drivers.'' IIHS highlighted its crash data analyses
for FCW-equipped vehicles stating, ``Our analyses of police-reported
crashes and insurance loss data indicate that most FCW systems are
effective for preventing rear-end crashes despite disparate designs.
Cicchino (2017) examined rear-end crash involvement rates for vehicles
with FCW from five automakers relative to vehicles without the system.
The presence of FCW was associated with statistically significant
reductions in rear-end crash involvement rates for three of the five
automakers.''
Some commenters suggested that the FCW requirements should more
closely follow other related standards. Ford recommended establishing
FCW requirements similar to existing AEB regulations from Europe (UNECE
R152 \56\), Australia (ADR98 \57\), and Korea (KMVSS \58\) instead of
restricting the individual components of the warning. Hyundai opposed
``overly specifying details for FCW and oppose[d] the use of SAE J2400
standards (particularly 10-degree vision cone provision).'' Porsche's
comments sought additional flexibility and alignment with UNECE
Regulation No. 152.
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\56\ UN 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 [2020/1597] (OJ L 360
30.10.2020, p. 66, ELI: <a href="http://data.europa.eu/eli/reg/2020/1597/oj">http://data.europa.eu/eli/reg/2020/1597/oj</a>).
\57\ Australian Design Rule, Vehicle Standard (Australian Design
Rule 98/01--Advanced Emergency Braking for Passenger Vehicles and
Light Goods Vehicles) 2021.
\58\ Korean Motor Vehicle Safety Standard (KMVSS) Article 15-3,
``Advanced Emergency Braking Systems (AEBS).''
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Lastly, multiple commenters voiced support for standardization of
FCW characteristics. The GHSA indicated support for FCW
standardization, stating that ``increased consistency will bolster the
safety impact of these features as drivers become more accustomed to
what to expect and how to react when these systems are engaged.'' AAA
also expressed support for standardization, stating that ``consumers
would find it beneficial to standardize visual alert characteristics. .
. such as the location of the warning.'' AAA cited its previous testing
experience that found ``characteristics among vehicles significantly
vary with some warnings hardly noticeable relative to visual warnings
presented in other vehicles.'' As a result, AAA urged NHTSA to
``consider standardization requirements for visual alerts to promote
consistency and understanding for all drivers, particularly hearing-
impaired drivers who may not perceive an auditory signal.''
Agency Response
NHTSA notes the general support from commenters for requiring some
kind of FCW to be presented prior to AEB activation. The point of FCW
is to elicit a timely and productive crash avoidance response from the
driver, thereby mitigating or, if possible, avoiding the need for AEB
to intervene in a crash-imminent situation. The proposed FCW
characteristics outlined in the NPRM are based on more than 35 NHTSA
research efforts related to crash avoidance warnings or forward
collision warnings conducted over the past nearly 30 years. Other
research, existing standards (ISO Standards 15623 and 22839), and SAE
documents (J3029 and J2400) also were considered as input for the
proposed requirements. While multiple commenters sought flexibility for
automakers to use an FCW of their own preference in lieu of one
conforming to the proposed specification, no safety data were provided
concerning consumers' degree of understanding of the wide variety of
existing FCW implementations--just generalized statements about
consumer familiarity. NHTSA does not view these arguments as sufficient
to overcome the value of standardization as a means of ensuring
consumer familiarity.
Data from NHTSA's 2023 AEB testing showed that each of six test
vehicle models from different manufacturers used a different FCW visual
signal or symbol. Only one model used the ISO FCW symbol. FCW visual
symbols that differ by manufacturer and, in some cases across models
from the same manufacturer, are likely to lead to confusion among
consumers. The observed substantial variety in existing FCW
implementations highlights the need for improved consistency of FCW
visual symbols to increase efficient comprehension of crash-imminent
warnings by vehicle operators and aid them in understanding the reason
for
[[Page 39717]]
their vehicle's (or, indeed, an unfamiliar rental vehicle's) active
crash avoidance intervention. Allowing for individual design choices--
even those with positive safety records--does not address this
important safety consideration.
Such confusion has also been documented by past research. Research
by industry published in a 2004 SAE paper focused on comprehension
testing of active safety symbols and assessed the ISO FCW symbol and
the SAE J2400 FCW symbol to assess their ability to communicate the
idea, ``Warning: You may be about to crash into a car in front of
you.'' Results of that research showed the ISO FCW symbol to have 45
percent ``high comprehension'' and the SAE J2400 symbol to have 23
percent high comprehension. However, while high comprehension was noted
for the lead vehicle crash scenario, NHTSA is not aware of any data
supporting effectiveness of the ISO FCW symbol for communicating the
idea of an impending forward pedestrian crash.'' \59\
---------------------------------------------------------------------------
\59\ Campbell, John & Hoffmeister, David & Kiefer, Raymond &
Selke, Daniel & Green, Paul & Richman, Joel. (2004). Comprehension
Testing of Active Safety Symbols. 10.4271/2004-01-0450.
---------------------------------------------------------------------------
NHTSA acknowledges the research by IIHS showing crash reduction
benefits from some existing FCW designs. IIHS research results found
that some automakers' FCW designs were associated with higher crash
reductions than others. However, this research did not evaluate FCW
characteristics by automaker or by model for vehicle models it studied
and whether such characteristics may have contributed to FCW
effectiveness differences, so care should be taken when drawing
conclusions. Regardless, while the IIHS studies have shown some
existing FCW in light vehicles are effective for preventing rear-end
crashes, research does not support an argument against taking other
measures to increase FCW effectiveness, as this action seeks to do. It
is likely that increasing the consistency of FCW characteristics and
standardization of the primary warning signals across vehicles and
models will lead to benefits beyond those documented to date due to
increased driver understanding of the meaning of FCW signals.
The agency disagrees with Volkswagen's comment that explanations in
the owner's manual adequately inform consumers about manufacturer-
specific FCW signals. A British study found that only 29% of motorists
surveyed had read their car handbook in full.\60\ That same study
examined owner's manual word counts and estimated that the time
required to read some of the longest would take up to 12 hours. An
April 2022 Forbes article states that ``the average new-vehicle's
owners' manuals, which, concurrent with the complexity of contemporary
cars, have become imposingly thick and mind-numbing tomes of what
should be essential information... remain unread in their respective
models' gloveboxes.'' \61\ With these concerns in mind, NHTSA does not
believe that owner's manual information is an acceptable substitute for
standardization of this important safety functionality across all
vehicles.
---------------------------------------------------------------------------
\60\ ``Car Handbooks Are Longer Than Many Famous Novels--Have
You Read Yours?'' <a href="https://www.bristolstreet.co.uk/news/car-handbooks-are-longer-than-many-famous-novels--have-you-read-yours/">https://www.bristolstreet.co.uk/news/car-handbooks-are-longer-than-many-famous-novels--have-you-read-yours/</a>.
\61\ ``Here's Why Nobody Reads Their Car's Owner's Manual''
<a href="https://www.forbes.com/sites/jimgorzelany/2022/04/07/heres-why-nobody-reads-their-cars-owners-manual/?sh=2a76d5d4462d">https://www.forbes.com/sites/jimgorzelany/2022/04/07/heres-why-nobody-reads-their-cars-owners-manual/?sh=2a76d5d4462d</a>.
---------------------------------------------------------------------------
After careful review of these comments, NHTSA has decided to adopt
a majority of the proposed FCW requirements unchanged as described in
the following sections.
a. FCW Signal Modality
NHTSA proposed that FCW modalities and related characteristics of
auditory and visual components be the same for lead vehicle AEB and
PAEB performance, and that the FCW be presented to the vehicle operator
via at least two sensory modalities--auditory and visual. The FCW
auditory signal was proposed to be the primary means used to direct the
vehicle operator's attention to the forward roadway. NHTSA did not
propose to require a haptic FCW signal component but invited comment on
whether requiring FCW to contain a haptic component presented via any
location may increase FCW effectiveness or whether an FCW haptic signal
presented in only one standardized location should be allowed.
Comments
Of those commenting on FCW signal modality, all supported a
multimodal FCW signal strategy. Multiple commenters including NTSB,
Consumer Reports, Ford, GHSA, Honda, MEMA, and Porsche expressed
support for the combination of auditory and visual warning modalities
that was proposed by NHTSA. For example, NTSB expressed support for
visual and auditory warning, and noted several NTSB investigations in
which visual warnings were found to be ineffective in capturing
drivers' attention. GHSA expressed support for requiring standardized
auditory and visual warnings when a collision is imminent, believing
that increased consistency would bolster the safety impact of these
features. Ford supported an auditory and visual alert based on their
experience implementing an FCW system. Honda stated that a multimodal
auditory and visual warning provided sufficient redundancy. Consumer
Reports also highlighted the importance of providing a visual warning
for those who are hearing impaired, who are listening to music, or are
otherwise distracted.
The remaining supporters of the multimodal approach preferred the
flexibility to use any combination of possible modalities (auditory,
visual and haptic). These included the Alliance, ASC, Bosch, GM, HATCI,
and Rivian. For example, the Alliance agreed with the agency's
conclusion that the auditory signal should be the primary means of
communicating with the driver, but expressed support for allowing
warnings to be provided using any combination of two of the three alert
modalities, with a third allowable, but not required. ASC recommended
that the warnings be aligned with UNECE Regulation No. 152. ASC and ZF
also cited research showing FCW with auditory and haptic components
prompt a quicker driver reaction time than FCW with auditory and visual
components.
Ford and MEMA agreed that OEMs should be permitted to supplement
the primary auditory and visual FCW signal modalities with a haptic
warning component. Bosch encouraged NHTSA to include haptic as one of
the warning modes, citing the potential for advantages in loud
environments or with hearing impaired individuals. Volkswagen agreed
with NHTSA's proposal to not require an FCW haptic component, but
clarified that if haptic was required, then only two out of the three
warning types should be required. HATCI requested that NHTSA permit
haptic signals to be used as the primary or secondary warning, stating
that haptic warnings draw the driver's attention to the hazard without
requiring them to identify a warning symbol with their eyes.
Consumer Reports suggested that a haptic signal may cause driver
confusion because haptic steering signals are also used by many lane
departure warning systems, which activate more frequently. Along the
same line, Porsche noted its desire ``to avoid causing driver confusion
related to other safety systems where haptic signals may be more
appropriate (e.g.,
[[Page 39718]]
steering wheel vibration used for lane keeping).''
Agency Response
After consideration of the comments, NHTSA is moving forward with
the originally proposed requirements for a primary FCW auditory signal
and a secondary visual signal, while neither requiring nor prohibiting
a supplementary FCW haptic signal. While a few commenters expressed the
desire to require a haptic FCW signal, no supporting data were
provided. Therefore, NHTSA declines to make a haptic warning signal a
requirement. However, NHTSA cautions those interested in implementing
supplementary FCW haptic signals to take steps to ensure that the
haptic signal used will not be confused with those currently used in
association with systems not designed to elicit a forward crash
avoidance response, for example, lane-keeping driver assistance
features.
b. FCW Auditory Signal Requirements
NHTSA proposed that the FCW auditory signal would be the primary
warning modality and asserted criteria to ensure that the FCW would be
successful in quickly capturing the driver's attention, directing the
driver's attention to the forward roadway, and compelling the driver to
quickly apply the brakes. NHTSA proposed that the FCW auditory signal's
fundamental frequency be at least 800 Hz and that it include a duty
cycle, or percentage of time the sound is present, of 0.25-0.95, and a
tempo in the range of 6-12 pulses per second. This final rule also
includes FCW requirements that were discussed in the NPRM.
Specifically, the FCW auditory signal is required to have a minimum
intensity of 15-30 dB above the masked threshold.
Comments
GHSA, Honda, and Rivian supported the proposed standardized FCW
auditory signal requirements. Honda stated that the proposed tone,
tempo, and frequency would contribute to making this a distinct and
recognizable warning, especially if standardized across the fleet.
Rivian agreed that a common FCW auditory signal is necessary so that
drivers can easily recognize warning conditions across different
vehicle makers and models.
Multiple commenters, including the Alliance, Ford, Nissan, Porsche,
Toyota, and Volkswagen indicated a preference for more flexibility in
the allowed FCW auditory signal characteristics. More specifically, the
Alliance and Nissan stated that not defining the required sound level
and characteristics is consistent with UNECE Regulation No. 152. Ford
recommended that the manufacturer be provided with flexibility to
design FCW auditory warning signals. Ford stated that the parameters
for an audible alert are often tuned for different vehicle applications
or customizable by drivers. Both Porsche and Volkswagen contended that
consumers may be used to existing FCW auditory signals used in current
vehicles. Volkswagen further stated that allowing flexibility in FCW
auditory signal characteristics enables manufacturers to update or
adjust the warnings as technologies evolve.
Regarding FCW auditory signal distinguishability, IIHS recommended
that NHTSA consider IIHS's method for assessing auditory seat belt
reminders to ensure auditory FCWs are easily discerned by drivers
beyond ambient levels of sound inside the vehicle.
On the issue of FCW auditory signal deactivation, Hyundai MOBIS
encouraged NHTSA to consider permitting the audible warning to be
suppressed as long as the FCW visual warning remains illuminated.
Agency Response
The FCW auditory signal minimum intensity requirement was
inadvertently left out of the proposed regulatory text, although it was
discussed in the preamble of the NPRM. Multiple commenters addressed
the topic of FCW auditory signal intensity in their comments. While
multiple commenters disagreed with NHTSA's proposed FCW auditory signal
criteria, NHTSA's data from 2023 AEB testing also showed that some
existing systems already meet some of the FCW proposed requirements.
One vehicle, a 2024 Mazda CX-90, met all proposed FCW auditory
requirements. Two vehicles met all proposed auditory requirements
except the minimum intensity requirement of 15-30 dB above the masked
threshold. Two other vehicles met 3 of the 5 FCW auditory signal
requirements while the last vehicle met only 2 of the 5 requirements.
All six vehicles' FCW auditory signals met the proposed duty cycle
requirement and four of the six met the fundamental frequency
requirement. Some variety in AEB test vehicles' FCW auditory signals
was also seen. FCW auditory signal intensities above the masked
threshold spanned a range of 28.8 dBA and five of the six tested
vehicles did not meet the proposed intensity requirement. FCW auditory
signals fundamental frequencies ranged from 600 to 2000 Hz.
NHTSA believes that auditory signal intensities are especially
important for FCW because of the urgency of the crash-imminent
situation, the goal of compelling a driver to apply the brakes, and the
speed with which action is necessary. Additionally, the minimum sound
intensity is supported by research that provides a strong foundation
for this requirement. Commenters who did not support the proposed FCW
auditory signal requirements provided no data to document the
effectiveness of existing FCW auditory signals, nor the purported
benefits of permitting vehicle manufacturers to choose their own unique
FCW designs. While providing flexibility for design choices that have
been proven to increase safety is valuable, providing flexibility that
allows for differences related to branding or that just serves to make
a model unique does not add safety value.
Regarding Ford's comment expressing interest in the ability to
decrease FCW auditory signal intensity when the driver's alertness
level is confirmed to be high, NHTSA notes that the proposed
requirements provide leeway for manufacturers to implement a less
invasive advisory or preliminary alert that would precede the required
FCW. It also would not prevent multiple intensities that all meet the
minimum requirement in this final rule.
NHTSA disagrees with the suggestion by Hyundai MOBIS to permit the
auditory warning to be suppressed as long as the FCW visual warning
remains illuminated. As the FCW auditory signal is considered the
primary means of warning a potentially inattentive driver, allowing the
auditory FCW signal to be suppressed would undercut its important
safety function.
After considering the comments, NHTSA has decided to finalize the
proposed FCW auditory signal intensity discussed in the preamble of the
NPRM in this final rule.
c. FCW Auditory Signal Presentation With Simultaneous Muting of Other
In-Vehicle Audio
In the preamble to the NPRM, NHTSA explained its intent to require
muting or substantial reduction in volume of other in-vehicle audio
(i.e., entertainment and other non-critical audio information) during
the presentation of the FCW. This requirement would serve to ensure
that the FCW auditory signal is conspicuous to the vehicle operator and
detectable at the critical moment at which a crash avoidance response
by the driver is needed. However, this intended requirement was
inadvertently left out of the proposed regulatory text.
Comments
ASC, MEMA, and ZF supported the muting or reducing other in-vehicle
[[Page 39719]]
audio during an audio FCW alert because the FCW alert is the highest
priority in the vehicle and should override all other sounds. ASC and
MEMA suggested that FCW alert volume should rise with speed to overcome
external sounds like wind noise or road noise.
Honda, Porsche and Volkswagen opposed muting of other in-vehicle
audio during FCW presentation. Honda stated that, because environmental
sound levels can vary drastically, it is unnecessary to require audio
muting. Honda cited the lack of a sound level requirement for the FMVSS
No. 208 seatbelt warning as rationale for not needing such a
requirement for FCW. Porsche and Volkswagen suggested that it is the
driver's responsibility to ensure that in-vehicle audio does not
interfere with the driving task. Volkswagen cited the requirement of a
both a visual and audio warning as justification for not requiring
muting of in-vehicle audio. Volkswagen also questioned how to
accommodate other mandatory audio signals if these occur simultaneous
with the collision warning.
Agency Response
Regarding Honda's comparison to the FMVSS No. 208 auditory warning
signal requirement for fastening seatbelts, NHTSA does not believe the
two requirements are comparable. The immediate consequences associated
with an impending forward crash are not comparable to those associated
with vehicle occupants fastening seat belts at the start of a drive.
In response to concerns expressed by Volkswagen and Porsche about
addressing multiple simultaneous auditory signals, NHTSA will clarify
that the audio required to be muted would be any audio for other than
crash avoidance or safety purposes, such as music or other
entertainment related audio.
Regarding the assertions by both Porsche and Volkswagen that
drivers are responsible for ensuring that in-vehicle audio system use
does not interfere with the driver's full attention to the driving
task, the situations in which FCW is expected to emit sound are urgent
enough that the most attentive driver would need to be able to hear the
auditory signal. NHTSA does not believe that attention or inattention
is the crux of the issue, though inattention could complicate a
driver's response. It is important to ensure that the FCW auditory
signal is audible even when sound levels from in-vehicle sources are
high.
Although the requirement to mute other in-vehicle audio during the
presentation of the FCW was inadvertently left out of the proposed
regulatory text, NHTSA is including such a requirement in this final
rule. Similar to the issue of auditory intensity, multiple commenters
addressed the topic of muting. The requirement will be finalized to
require that in-vehicle audio not related to a safety purpose or safety
system (i.e., entertainment and other audio content not related to or
essential for safe performance of the driving task) must be muted, or
reduced in volume to within 5 dB of the masked threshold, during
presentation of the FCW auditory signal. This specification will serve
to ensure that the amplitude of the FCW auditory signal is at least 10
dB above the masked threshold (MT) to preserve the saliency of the
auditory warning.\62\
---------------------------------------------------------------------------
\62\ 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].''
---------------------------------------------------------------------------
d. FCW Visual Symbol Requirements
NHTSA proposed that FCW visual signals must use the SAE J2400
(2003-08) symbol.\63\ The SAE J2400 symbol relates the idea of an
impending frontal crash without depicting a particular forward object
and, as such, is readily applicable to both lead vehicle and pedestrian
scenarios. 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 and because
NHTSA-sponsored research \64\ has shown that instrument-panel-based
crash warnings can draw drivers' eyes downward away from the roadway at
a critical time when crash avoidance action may be needed \65\ the
symbol would be required to be steady burning.
---------------------------------------------------------------------------
\63\ SAE J2400 2003-08 (Information report). Human Factors in
Forward Collision Warning Systems: Operating Characteristics and
User Interface Requirements.
\64\ DOT HS 812 191 September 2015, Evaluation of Heavy-Vehicle
Crash Warning Interfaces. <a href="https://www.nhtsa.gov/sites/nhtsa.gov/files/812191_evalheavyvehiclecrashwarninterface.pdf">https://www.nhtsa.gov/sites/nhtsa.gov/files/812191_evalheavyvehiclecrashwarninterface.pdf</a>.
\65\ ``Evaluation of Forward Collision Warning System Visual
Alert Candidates and SAE J2400,'' SAE Paper No. 2009-01-0547,
<a href="https://trid.trb.org/view/1430473">https://trid.trb.org/view/1430473</a>.
---------------------------------------------------------------------------
Comments
Multiple commenters voiced support for standardization of FCW
characteristics. For example, the Governors Highway Safety Association
(GHSA) indicated support for FCW standardization, stating that
increased consistency will bolster the safety impact of these features.
AAA cited its previous testing experience that some warnings were
hardly noticeable relative to visual warnings presented in other
vehicles.
Multiple commenters were opposed to specificity included in the
proposed FCW requirements. These commenters thought that the state of
varied implementation of FCW that exists currently was sufficient. For
example, Volkswagen described the proposed warning strategy for AEB as
too prescriptive. Volkswagen thought the regulation should specify the
warning modes, but leave the implementation up to the manufacturer if
the warning is easily perceivable and visually distinguishable from
other warnings. Volkswagen thought that variation in FCW strategy
across manufacturers would not be a problem because manufacturers
explain their warning strategy in their owner's manuals. NADA, Nissan,
Mitsubishi, and Porsche also suggested manufacturers have more
flexibility to choose the form of visual warning.
The Alliance opined that NHTSA should allow flexibility for
manufacturers to select the visual warnings deemed to be most effective
in the context of the overall vehicle human-machine interface, which
could include ISO or SAE symbols, word-based warnings, or other
flashing or steady burning illumination as appropriate. The Alliance
stated that NHTSA has not presented data to indicate that any one
visual alert type or symbol is any more or less effective than another.
Consumer Reports supported standardization but recommended that a word
be used rather than a symbol.
Some commenters suggested that the FCW requirements should more
closely follow other related standards. Ford recommended establishing
FCW requirements similar to existing AEB regulations from Europe,\66\
Australia,\67\
[[Page 39720]]
and Korea \68\ instead of restricting the individual components of the
warning. Hyundai opposed the use of SAE J2400 standards, including the
symbol. Hyundai believed it was more appropriate to adopt ISO 15623.
Porsche's comments seek additional flexibility and alignment with UNECE
Regulation No. 152.
---------------------------------------------------------------------------
\66\ UN 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 [2020/1597] (OJ L 360
30.10.2020, p. 66, ELI: <a href="http://data.europa.eu/eli/reg/2020/1597/oj">http://data.europa.eu/eli/reg/2020/1597/oj</a>).
\67\ Australian Design Rule, Vehicle Standard (Australian Design
Rule 98/01--Advanced Emergency Braking for Passenger Vehicles and
Light Goods Vehicles) 2021.
\68\ Korean Motor Vehicle Safety Standard (KMVSS) Article 15-3,
``Advanced Emergency Braking Systems (AEBS).''
---------------------------------------------------------------------------
Hyundai MOBIS, Toyota, the Alliance, Ford, and Honda, disagreed
with the steady burning requirement for the FCW visual signal,
expressing support for allowing it to flash. Honda recommended aligning
with the specifications of ISO 15008.
Honda supported both visual symbol and word-based FCW options.
Honda recommended that NHTSA allow flexibility to continue using
already well understood text-based warnings like ``BRAKE!,'' which
Honda currently employs, reasoning that a well-designed warning would
instruct drivers what to do to avoid a hazard. Rivian also supported
allowing the use of the word, ``BRAKE,'' in lieu of an FCW visual
symbol.
Agency Response
After careful review of these comments, NHTSA has decided to adopt
the proposed standardized FCW visual warning requirements unchanged.
While multiple commenters sought flexibility for automakers to use an
FCW visual signal of their own choice rather than a standardized
signal, no safety data were provided concerning consumers' degree of
understanding of the wide variety of existing FCW implementations nor
any safety advantages or benefits of not standardizing the visual
symbol. The proposed FCW characteristics outlined in the NPRM are based
on more than 35 NHTSA research efforts related to crash avoidance
warnings or forward collision warnings conducted over the past nearly
30 years. Other research, existing standards (ISO Standards 15623 and
22839), and SAE documents (J3029 and J2400) also were considered as
input for the proposed requirements. NHTSA does not view the provided
arguments as sufficient to overcome the value of standardization as a
means of ensuring consumer familiarity and ensuring the applicability
of the chosen symbol to both lead vehicle and pedestrian scenarios.
Data from NHTSA's 2023 AEB testing showed that each of six test
vehicle models from different manufacturers used a different FCW visual
signal or symbol. Only one model used the ISO FCW symbol. FCW visual
symbols that differ by manufacturer and, in some cases across models
from the same manufacturer, are likely to lead to confusion among
consumers. The observed substantial variety in existing FCW
implementations highlights the need for improved consistency of FCW
visual symbols to increase efficient comprehension of crash-imminent
warnings by vehicle operators and aid them in understanding the reason
for their vehicle's (or an unfamiliar rental vehicle's) active crash
avoidance intervention. Allowing for individual design choices does not
address this important safety consideration.
Such confusion relating to automotive symbol comprehension has also
been documented by NHTSA research. Past research conducted by NHTSA to
assess comprehension of vehicle symbols including the ISO tire
pressure, ISO tire failure, and ISO engine symbols showed that while 95
percent of subjects correctly identified the engine symbol, recognition
percentages for the ISO tire pressure and tire failure icons were the
lowest of the 16 icons tested, 37.5 percent and 25 percent,
respectively.'' \69\ Research by industry published in a 2004 SAE paper
focused on comprehension testing of active safety symbols and assessed
the ISO FCW symbol and the SAE J2400 FCW symbol to assess their ability
to communicate the idea, ``Warning: You may be about to crash into a
car in front of you.'' Results of that research showed the ISO FCW
symbol to have 45 percent ``high comprehension'' and the SAE J2400
symbol to have 23 percent high comprehension. However, while high
comprehension was noted for the lead vehicle crash scenario, NHTSA is
not aware of any data supporting effectiveness of the ISO FCW symbol
for communicating the idea of an impending forward pedestrian crash.''
\70\
---------------------------------------------------------------------------
\69\ Mazzae, E.N. and Ranney, T.A. (2001). ``Development of an
Automotive Icon for Indication of Significant Tire Underinflation.''
Article in Proceedings of the Human Factors and Ergonomics Society
Annual Meeting [middot] October 2001. DOI: 10.1177/
154193120104502317.
\70\ Campbell, John & Hoffmeister, David & Kiefer, Raymond &
Selke, Daniel & Green, Paul & Richman, Joel. (2004). Comprehension
Testing of Active Safety Symbols. 10.4271/2004-01-0450.
---------------------------------------------------------------------------
Consumer Reports ``Guide to ADAS'' states that ``CR's most recent
survey data shows that industry-wide, only 48% of owners of vehicles
equipped with FCW say they understand how it works.'' \71\ NHTSA
believes that improved consistency of FCW visual symbols is important
to increase efficient comprehension of crash-imminent warnings.
---------------------------------------------------------------------------
\71\ Consumer Reports' Guide to ADAS Usability: Consumer
insights on understanding, use, and satisfaction of ADAS December
2022. <a href="https://data.consumerreports.org/wp-content/uploads/2021/09/consumer-reports-active-driving-assistance-systems-ux-guide-revised-december-09-2022.pdf">https://data.consumerreports.org/wp-content/uploads/2021/09/consumer-reports-active-driving-assistance-systems-ux-guide-revised-december-09-2022.pdf</a>.
---------------------------------------------------------------------------
NHTSA acknowledges the research by IIHS showing crash reduction
benefits from some existing FCW designs. IIHS research results found
that some automakers' FCW designs were associated with higher crash
reductions than others. However, this research did not evaluate FCW
characteristics by automaker or by model for vehicle models it studied
and whether such characteristics may have contributed to FCW
effectiveness differences, so care should be taken when drawing
conclusions. Regardless, the IIHS studies have shown some existing FCW
in light vehicles FCW systems are effective for preventing rear-end
crashes, research does not support an argument against taking other
measures to increase FCW effectiveness. It is likely that increasing
the consistency of FCW characteristics and standardization of the
primary warning signals across vehicles and models will lead to
benefits beyond those documented to date due to increased driver
understanding of the meaning of FCW signals.
The agency disagrees with Volkswagen's comment that explanations in
the owner's manual adequately inform consumers about manufacturer-
specific FCW signals. As noted previously, a British study found that
only 29% of motorists surveyed had read their car handbook in full.\72\
That same study examined owner's manual word counts and estimated that
the time required to read some of the longest would take up to 12
hours. An April 2022 Forbes article states that ``the average new-
vehicle's owners' manuals, which, concurrent with the complexity of
contemporary cars, have become imposingly thick and mind-numbing tomes
of what should be essential information . . . remain unread in their
respective models' gloveboxes.'' \73\ With these concerns in mind,
NHTSA does not believe that owner's manual information is an acceptable
substitute for standardization of this important safety functionality
across all vehicles.
---------------------------------------------------------------------------
\72\ ``Car Handbooks Are Longer Than Many Famous Novels--Have
You Read Yours?'' <a href="https://www.bristolstreet.co.uk/news/car-handbooks-are-longer-than-many-famous-novels--have-you-read-yours/">https://www.bristolstreet.co.uk/news/car-handbooks-are-longer-than-many-famous-novels--have-you-read-yours/</a>.
\73\ ``Here's Why Nobody Reads Their Car's Owner's Manual''
<a href="https://www.forbes.com/sites/jimgorzelany/2022/04/07/heres-why-nobody-reads-their-cars-owners-manual/?sh=2a76d5d4462d">https://www.forbes.com/sites/jimgorzelany/2022/04/07/heres-why-nobody-reads-their-cars-owners-manual/?sh=2a76d5d4462d</a>.
---------------------------------------------------------------------------
[[Page 39721]]
Finally, as for the use of words instead of a symbol, as noted in
the NPRM, word-based FCW visual warnings are used by some U.S. vehicle
models including, ``BRAKE!,'' ``BRAKE,'' and ``STOP!''. SAE J2400 also
includes a word-based visual warning recommendation consisting of the
word, ``WARNING.'' With regard to this existing use of word-based FCW
visual warnings in some models, research by Consumer Reports noted in
its online ``Guide to forward collision warning'' found that for some
models, visual warning word use was found to be confusing to some
drivers surveyed. Specifically, survey 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.'' \74\ While NHTSA
does find merit in the rationale for using an effective word-based
visual warning for FCW purposes, we have decided in favor of the value
of consistency across U.S. vehicles to promote consumer recognition of
a dedicated FCW symbol. This symbol-based strategy for the FCW visual
signal follows is consistent with the strategies of ISO 15623 and SAE
J2400 (2003-08).
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\74\ ``Guide to forward collision warning: How FCW helps drivers
avoid accidents.'' Consumer Reports. <a href="https://www.consumerreports.org/carsafety/forward-collision-warning-guide/">https://www.consumerreports.org/carsafety/forward-collision-warning-guide/</a>.
Accessed April 2022.
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NHTSA notes, however, that this requirement does not preclude the
use of a word-based warning that supplements the required FCW symbol
presentation. In that event, NHTSA agrees with Honda and Consumer
Reports that the word, ``BRAKE!'', including the exclamation point, is
likely the best choice for effective communication to the driver the
need for them to apply the brakes. NHTSA believes, as has been
suggested by Consumer Reports, that there is a tendency for drivers to
interpret some words used as warnings as describing an action being
performed by the vehicle, rather than a command to the driver. To avoid
such confusion by the driver, NHTSA recommends that manufacturers
wishing to complement the FCW symbol with a word-based warning use,
``BRAKE!'' to aid in drivers interpreting the word as an instruction.
Finally, with respect to the steady-burning requirement, NHTSA does
not agree with commenters recommending that the FCW visual warning be
allowed to flash. As the FCW visual signal is intended to be secondary
to the FCW auditory signal, allowing the symbol to flash in an attempt
to draw the drivers' attention could actually draw the drivers' gaze
downward to the instrument panel rather than to the forward roadway at
a critical time for the driver to initiate a crash avoidance response.
After evaluation of the comments, the agency has determined to
retain the proposal requirement for the visual symbol from SAE J2400
(2003-08), ``Human Factors in Forward Collision Warning Systems:
Operating Characteristics and User Interface Requirements''
(Information report), to communicate the idea of an impending frontal
crash without depicting a particular forward object. With no comments
opposed to requiring the FCW visual signal to be presented using the
color red, NHTSA is also finalizing that requirement as proposed and
clarifying that it will apply to the required FCW symbol and any
manufacturer-chosen words to accompany the required symbol.
e. FCW Visual Signal Location Requirements
The agency proposed that the FCW visual signal be presented within
a 10-degree cone of the driver's forward line of sight.\75\ This
requirement is based on SAE J2400, ``Human Factors in Forward Collision
Warning Systems: Operating Characteristics and User Interface
Requirements,'' paragraph 4.1.14. 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.''
Multiple research studies provide support for a visual warning location
close to the driver's forward line of sight. NHTSA-sponsored research
also supports this requirement, showing that instrument-panel-based
crash warnings can draw drivers' eyes downward away from the roadway at
a critical time when crash avoidance action may be needed.\76\
Industry-sponsored research published in 2009 also indicates that an
FCW visual signal presented in the instrument panel can slow driver
response.\77\ The 10-degree requirement would also increase the
likelihood of FCW visual signal detection by hearing-impaired drivers.
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\75\ Line of sight based on the forward-looking eye midpoint
(Mf) as described in FMVSS No. 111, ``Rear visibility,'' S14.1.5.
\76\ DOT HS 812 191 September 2015, Evaluation of Heavy-Vehicle
Crash Warning Interfaces. <a href="https://www.nhtsa.gov/sites/nhtsa.gov/files/812191_evalheavyvehiclecrashwarninterface.pdf">https://www.nhtsa.gov/sites/nhtsa.gov/files/812191_evalheavyvehiclecrashwarninterface.pdf</a>.
\77\ ``Evaluation of Forward Collision Warning System Visual
Alert Candidates and SAE J2400,'' SAE Paper No. 2009-01-0547,
<a href="https://trid.trb.org/view/1430473">https://trid.trb.org/view/1430473</a>.
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Comments
Consumer Reports and AAA supported the proposed requirement that
the FCW visual signal be presented in a location within a 10-degree
cone of the driver's forward line of sight. In contrast, multiple
commenters opposed the 10-degree cone requirement, some believing that
the requirement could only be met using a head-up display. A majority
of commenters who addressed this point requested that NHTSA consider
expanding the 10-degree cone of the driver's line of sight requirement
for FCW visual signal location.
FCA, Hyundai, Nissan, NADA, Rivian, and Volkswagen opposed the 10-
degree cone requirement. The Alliance disagrees that the SAE J2400
information report provides adequate justification for the 10-degree
requirement.
FCA thought the proposed requirement was impracticable. Rivian
recommended that the FCW visual signal be presented on the top location
of the driver instrument panel, in the instrument panel, or in a head-
up display unless NHTSA can demonstrate that the data indicates that
one location is clearly superior for driver perception. Toyota
requested that the cone size be expanded to allow for suitable
placement of the visual alert in areas such as the meter cluster or
multi-information display, which would still be clearly visible in
front of the driver.
Porsche recommended that NHTSA consider replacing the 10-degree
with an allowance of up to 30 degrees, arguing that this would
facilitate the use of long-established visual warning locations which
it viewed as sufficient to provide the necessary cues. Multiple
commenters, including Mitsubishi, the Alliance, and Honda, recommended
use of a 60-degree cone requirement. Mitsubishi explained that the 60-
degree value is based on a book chapter titled, Visual Fields, by R.H.
Spector, et al., which states the vertical viewing angle of humans to
be 60 degrees.
Agency Response
While many current vehicle models present an FCW visual signal
within the instrument panel, drawing a driver's eyes downward away from
the roadway in front of them 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. NHTSA's research
indicates that a visual FCW signal presented in the instrument panel
can draw drivers' eye gaze downward away from the forward roadway and
slow driver response to a forward crash-
[[Page 39722]]
imminent event.\78\ Further, Industry-sponsored research published in
2009 also indicates that an FCW visual signal presented in the
instrument panel can slow driver response.\79\
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\78\ DOT HS 812 191 September 2015, Evaluation of Heavy-Vehicle
Crash Warning Interfaces. <a href="https://www.nhtsa.gov/sites/nhtsa.gov/files/812191_evalheavyvehiclecrashwarninterface.pdf">https://www.nhtsa.gov/sites/nhtsa.gov/files/812191_evalheavyvehiclecrashwarninterface.pdf</a>.
\79\ ``Evaluation of Forward Collision Warning System Visual
Alert Candidates and SAE J2400,'' SAE Paper No. 2009-01-0547,
<a href="https://trid.trb.org/view/1430473">https://trid.trb.org/view/1430473</a>.
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Mitsubishi highlighted content from ``Visual Fields,'' by R.H.
Spector, et.al that states the vertical viewing angle of humans to be
60 degrees.\80\ Specter's chapter specifically states that ``a normal
visual field is an island of vision measuring 90 degrees temporally to
central fixation, 50 degrees superiorly and nasally, and 60 degrees
inferiorly.'' Mitsubishi contended that if the FCW visual warning is
displayed within this range, the driver will be able to recognize it.
However, the referenced Spector visual field information relates to
average humans' ability see objects presented before them and not
specifically to drivers' ability to detect and quickly respond to an
FCW visual signal within the potentially cluttered visual scene of a
driver's-view perspective. Research sponsored by NHTSA and industry,
respectively, has shown that instrument panel based visual crash
warnings can draw drivers' eyes downward away from the roadway at a
critical time when crash avoidance action may be needed and that an FCW
visual signal presented in the instrument panel can slow driver
response.<SUP>81 82</SUP> Comparison to other warnings is not apt
because other most other warnings do not require as immediate of a
response as FCW.
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\80\ Spector RH. Visual Fields. In: Walker HK, Hall WD, Hurst
JW, editors. Clinical Methods: The History, Physical, and Laboratory
Examinations. 3rd ed. Boston: Butterworths; 1990. Chapter 116. PMID:
21250064.
\81\ DOT HS 812 191 September 2015, Evaluation of Heavy-Vehicle
Crash Warning Interfaces. <a href="https://www.nhtsa.gov/sites/nhtsa.gov/files/812191_evalheavyvehiclecrashwarninterface.pdf">https://www.nhtsa.gov/sites/nhtsa.gov/files/812191_evalheavyvehiclecrashwarninterface.pdf</a>.
\82\ ``Evaluation of Forward Collision Warning System Visual
Alert Candidates and SAE J2400,'' SAE Paper No. 2009-01-0547,
<a href="https://trid.trb.org/view/1430473">https://trid.trb.org/view/1430473</a>.
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As the text of SAE J2400 states, locating the FCW visual signal
within a 10-degree cone could be accomplished in a top-of-dashboard
location, NHTSA did not intend to require presentation of the FCW
visual signal only via head-up display. To evaluate the potential
difficulties associated with attempting to meet this FCW visual symbol
location requirement, NHTSA gathered additional information regarding
what visual angle about the driver's forward line of sight could be
used to locate the FCW visual signal near the driver's forward line of
sight, such as within the upper center portion of the instrument panel,
without requiring substantial redesign of vehicles' instrument panels
or dashboards, or require a head-up display.
NHTSA gathered information regarding the driver's visual angle when
looking at the instrument panel for a set of 10 light vehicles. Eight
of the vehicles were model year 2022, one was from the 2021 model year,
and one was from model year 2023. Vehicle makes examined spanned a wide
range of manufacturers including Chevrolet, Ford, Honda, Hyundai, Jeep,
Nissan, RAM Subaru, Toyota, and Volkswagen. The vehicles examined also
spanned a range of vehicle sizes including two large pickup trucks.
NHTSA used a coordinate measuring machine to record within a single
coordinate system the locations of the upper and lower extents of the
active display area of each vehicle's instrument panel, as well as the
left and right extents of the instrument panel. These points were used
to locate the geometric center of the instrument panel. The eye
midpoint location for a properly seated 50th percentile male driver was
also located using an H-point machine and recorded. The 50th percentile
male driver size was used to represent the midpoint of the range of
possible driver eye midpoint locations across all driver sizes. This
full set of coordinate data was used to calculate visual angles between
the eye midpoint and each of the center and upper and lower extents of
the vehicles' instrument panels at their horizontal center. The plot
below depicts visual angle calculation results for the instrument panel
central upper edge, center point, and central lower edge for a 50th
male driver's point of view.
[[Page 39723]]
[GRAPHIC] [TIFF OMITTED] TR09MY24.022
Visual angle values for the instrument panel center point for these
vehicles were found to range from 15.7 to 18.5 degrees. Nine of the ten
vehicles were found to have instrument panel center locations that
reside within 18 degrees downward of the driver's forward horizontal
line of sight. Based on these data, NHTSA believes that revising the
FCW visual symbol location 10-degree requirement to an 18-degree
vertical angle would permit the large majority of current vehicle
designs to display a telltale-sized or larger FCW visual symbol in the
upper half of the instrument panel without any structural redesign or
necessity of using a head-up display. Therefore, NHTSA has decided to
expand the vertical angle to 18 degrees while retaining the 10-degree
horizontal angle. The 10-degree value is being retained for the
horizontal angle to preserve the FCW symbol's presentation at the
center of the driver's forward field of view to maximize its
perceptibility.
2. AEB Requirement
a. AEB Deactivation
NHTSA discussed the issue of AEB deactivation in various
circumstances, and the various ways it might become deactivated (i.e.,
manually or automatically). NHTSA used both ``disablement'' and
``deactivation'' in the proposal, intending that those terms mean the
same thing. The NPRM proposed prohibiting manual AEB system
deactivation at any speed above the proposed 10 km/h minimum speed
threshold for AEB system operation. NHTSA sought comment on this and
whether the agency should permit manual deactivation similar to that
permitted for ESC systems in FMVSS No. 126. NHTSA also sought comment
on the appropriate performance requirements if the standard permitted
installation of a manually operated deactivation switch.
Regarding automatic deactivation, NHTSA stated that it anticipated
driving situations in which AEB activation may not increase safety and
in some rare cases may increase risk. For instance, an AEB system where
sensors have been compromised because of misalignment, frayed wiring,
or other partial failure, could provide the perception system with
incomplete information that is misinterpreted and causes a dangerous
vehicle maneuver. In instances where a light vehicle is towing a
trailer with no independent brakes, or with brakes that do not include
stability control functions, emergency braking may cause jack-knifing,
or other dangerous outcomes. In the proposal, NHTSA stated that it was
considering restricting the automatic deactivation of the AEB system
generally and sought comment on 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 situations, NHTSA requested comment on
allowing the AEB system to be placed in a nonfunctioning mode whenever
the vehicle is in 4-wheel drive low or the ESC is turned off, and
whenever equipment is attached to the vehicle that might interfere with
the AEB system's sensors or perception system, such as a snowplow.
NHTSA requested 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.
Comments
Several commenters discussed AEB deactivation. The City of
Philadelphia, the Richmond Ambulance Authority, DRIVE SMART Virginia,
the National Association of City Transportation Officials (NACTO),
Advocates for Highway and Auto Safety (Advocates), the Nashville
Department of Transportation and Multimodal Infrastructure, and the
City of Houston supported the proposed requirement to prevent AEB
deactivation. In general, they stated that allowing system deactivation
would diminish safety benefits.
In contrast, many commenters stated that AEB deactivation should be
allowed. For example, ASC, ZF, MEMA, NADA, Mitsubishi, Porsche, Aptiv
and Volkswagen suggested that the agency should follow the specific
deactivation criteria under UNECE Regulation No. 152. That regulation
requires at least
[[Page 39724]]
two deliberate actions to deactivate the AEB system, and the system
must default back to ``on'' after each ignition cycle.\83\ Toyota,
Porsche, and Hyundai stated that manual deactivation for AEB systems
should be similar to what is allowed for ESC systems in FMVSS No. 126.
Rivian stated that manual deactivation should be allowed via either a
software or hardware switch.
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\83\ UN 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 [2020/1597] (OJ L 360
30.10.2020, p. 66, ELI: <a href="http://data.europa.eu/eli/reg/2020/1597/oj">http://data.europa.eu/eli/reg/2020/1597/oj</a>).
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Advocates opposed allowing deactivation of AEB systems, but they
provided some suggestions for NHTSA if deactivation were allowed in
narrowly tailored instances for specific applications with strong
justification and supporting data. Advocates stated that any conditions
allowed for automatic deactivation must not enable a means to
intentionally deactivate the AEB system and suggest that any
deactivation should trigger the malfunction telltale and be recorded as
part of a data recording requirement. If NHTSA were to allow manual AEB
deactivation, Advocates thought the process should require multiple
steps while the vehicle is not moving and require drivers to engage in
a deliberate and significant effort (i.e. a driver should not be able
to disable AEB by pressing a single button). Advocates aligned with
other commenters in suggesting that if any AEB deactivation occur, the
system should default back to ``on'' at any new ignition cycle.
The Alliance, Honda, NADA, Porsche, and Volkswagen suggested that
the agency should allow manual deactivation to mitigate consumer
dissatisfaction. Honda and NADA also stated that not allowing
deactivation may lead to substantially higher false positive rates,
while AAA stated that allowing for automatic or manual deactivation
could increase consumer acceptance and minimize the perception that the
systems are overbearing. NADA also stated that AEB false positives are
a significant source of consumer complaints about AEB systems and that
only 59 percent of respondents to a Consumer Reports survey indicated
that they were satisfied with their AEB systems. The Alliance stated
that in many cases, the circumstances warranting AEB deactivation are
already described in vehicle owner's manuals or other information
sources, and that it supports the continuation of describing such
circumstances to the user.
ASC stated that for ADAS-equipped vehicles where the primary
operating responsibility belongs to the driver, AEB is an assist
function and the driver should be able to deactivate the AEB system if
required. ASC also stated that under extreme operating or environmental
conditions, the AEB system may be outside its operating design domain
and should automatically deactivate (temporarily) and that in some
situations such as testing, or service, the AEB system should be able
to be deactivated.
SEMA, Ford, The Alliance, Rivian, Volkswagen, and HATCI suggested
that there are likely several circumstances where deactivation of the
system may be needed to ensure a safe vehicle operation, including
track use, off-road use, and car washes. Some specific examples
suggested by commenters include the use of chains on tires for
traction, towing, four-wheel drive, low traction driving scenarios, and
off-roading. SEMA and Mitsubishi stated that on a vehicle towing a
trailer without an independent brake system, AEB activation may cause
jack-knifing or other dangerous conditions. MEMA stated that drivers of
many existing vehicles can currently disable their AEB system in cases
where the AEB system is predictably, but incorrectly, triggered by
objects or structures.
NTEA stated that there is a need to be able to deactivate AEB when
certain vocational equipment is attached in frontal areas where it
intrudes into the field-of-view of an AEB system. NTEA stated that
final stage manufacturers and alterers are not currently (nor
foreseeably in the future) able to move/reinstall/recalibrate these
systems to accommodate vocational upfits that can be in direct conflict
with how these systems need to function. NTEA uses snowplows as an
example of a vehicle equipment for which sensor relocation cannot
accommodate AEB. NTEA stated, as an example of how provisions for
deactivation could be included in the requirement, that one vehicle
manufacturer has previously created a method to detect the presence of
a plow blade in their electrical architecture, so that when the blade
is attached, AEB is deactivated. AEB functionality resumes when the
blade hardware is removed. NTEA provided examples of other front-
mounted equipment such as winches, sirens and push bumpers on emergency
vehicles that could cause unintended consequences with the system
reaction of AEB. Further, NTEA identified operational aspects of
emergency and first responder vehicles that merit more consideration
for AEB deactivation.
The Alliance and Porsche stated that NHTSA should provide
manufacturers with the ability to define automatic deactivation
criteria. While Volkswagen stated that NHTSA should provide a list of
situations where automatic deactivation is allowed it stated that this
list should not be mandatory and joined the Alliance and Porsche in
stating that OEM's should establish the situations where the AEB system
is permitted to automatically deactivate, or otherwise restrict braking
authority granted to the AEB system. HATCI did not specifically comment
on the list of situations, but stated that allowing manual deactivation
would provide affordances for unforeseen scenarios that industry and
NHTSA have not yet contemplated which would help futureproof against
situations that may not exist today. The Alliance stated that this
approach introduces additional complexity in terms of demonstrating
compliance with the standard. Porsche stated that providing a not
``overly intrusive'' deactivation warning message would be appropriate
and that the range of situations in which the systems would be
automatically deactivated be infrequent and of limited duration.
Finally, the Alliance also addressed whether the deactivation of
ESC may cause deactivation of AEB. While not encouraged, a driver
seeking to disable AEB may be left with no option but to turn both AEB
and ESC systems off under NHTSA's proposal, reducing potential safety
benefits from having the ESC system remain active.
Agency Response
In this final rule, NHTSA does not allow for vehicles to be
equipped with a manual control whose sole functionality is the
deactivation of the AEB system. NHTSA agrees with the commenters who
noted concerns about diminishing the safety benefits of this rule.
Harmonization alone is an insufficient justification for allowing a
control to deactivate the AEB system. Commenters have not explained why
there is a safety need of a dedicated deactivation control or why a
dedicated deactivation control would not diminish the safety benefits
of AEB. The agency also disagrees with ASC's assertion that AEB is an
``assist function,'' and even if true, that such a description would
serve as a justification for allowing a manual deactivation control.
NHTSA does not agree that any theoretical consumer dissatisfaction
is one of the circumstances that justify allowing manual deactivation.
AEB systems have been available on vehicles for many years. It is not
reasonable to assume that there will be consumer acceptance issues due
to the requirements of this final rule.
[[Page 39725]]
NHTSA is not persuaded by comments that suggest that not permitting
deactivation would lead to substantially higher false positive rates.
NHTSA recognizes that AEB false positives are a source of consumer
complaints, but NHTSA does not believe AEB deactivation is the solution
to the engineering challenges manufacturers with lower performing
systems might face in meeting this rule's requirements.
That said, NHTSA recognizes that there are certain circumstances
where deactivation may be appropriate, and the commenters raise several
situations where NHTSA believes automatic deactivation would be the
best approach. Examples of such a scenario include when a trailer is
being towed, or when a snowplow is attached to a pickup truck. AEB
activation while towing a trailer may be unsafe if the trailer does not
have brakes. A snowplow may interfere with the sensing capabilities of
the AEB system. In such cases, NHTSA expects that the manufacturer
would automatically disable AEB functionality when interference with
the sensing capabilities occurs. Using the example of towing, NHTSA
expects that the manufacturer would design AEB to scan for towing
connections and automatically disable AEB if it registers any.
NHTSA agrees that it is important for the AEB system to default
back to ``on'' after each ignition cycle, except in one circumstance--
in a low-range four-wheel drive configuration selected by the driver on
the previous ignition cycle that is designed for low-speed, off-road
driving. In that situation, NHTSA believes that reverting to the
manufacturer's original default AEB setting would not be necessary.
There is a similar exception for the ESC Off control.
NHTSA also agrees with the Advocates that any deactivation should
trigger the malfunction telltale because consistent illumination is
important to remind drivers that safety equipment (i.e., AEB) is not
functioning as the driver expects. Should the OEM design its systems in
a way where the AEB system would automatically deactivate when the
system detects that it cannot function properly (i.e., change
performance in a way that takes the AEB system out of compliance with
the requirements of the standard), then the driver must be alerted of
this performance issue through a telltale. This applies to partial or
full disablement of the system.
NHTSA does not agree with the Alliance that restricting the
installation of an ``AEB off'' control leaves a driver seeking to
disable AEB with no option but to turn both AEB and ESC systems off.
First, it is up to the manufacturer to decide if AEB is automatically
turned off when ESC is turned off. Second, while it is not restricted
by the FMVSS, it is the manufacturer's choice to install an
[…truncated; see source link]Indexed from Federal Register on May 9, 2024.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.