Proposed Rule2023-13622
Heavy Vehicle Automatic Emergency Braking; AEB Test Devices
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
July 6, 2023
Issuing agencies
Transportation DepartmentNational Highway Traffic Safety AdministrationFederal Motor Carrier Safety Administration
Abstract
This NPRM proposes to adopt a new Federal Motor Vehicle Safety Standard (FMVSS) to require automatic emergency braking (AEB) systems on heavy vehicles, i.e., vehicles with a gross vehicle weight rating greater than 4,536 kilograms (10,000 pounds). This notice also proposes to amend FMVSS No. 136 to require nearly all heavy vehicles to have an electronic stability control system that meets the equipment requirements, general system operational capability requirements, and malfunction detection requirements of FMVSS No. 136. An AEB system uses multiple sensor technologies and sub-systems that work together to sense when the vehicle is in a crash imminent situation and automatically applies the vehicle brakes if the driver has not done so or automatically applies more braking force to supplement the driver's applied braking. This NPRM follows NHTSA's 2015 grant of a petition for rulemaking from the Truck Safety Coalition, the Center for Auto Safety, Advocates for Highway and Auto Safety and Road Safe America, requesting that NHTSA establish a safety standard to require AEB on certain heavy vehicles. This NPRM also responds to a mandate under the Bipartisan Infrastructure Law, as enacted as the Infrastructure Investment and Jobs Act, directing the Department to prescribe an FMVSS that requires heavy commercial vehicles with FMVSS-required electronic stability control systems to be equipped with an AEB system, and also promotes DOT's January 2022 National Roadway Safety Strategy to initiate a rulemaking to require AEB on heavy trucks. This NPRM also proposes Federal Motor Carrier Safety Regulations requiring the electronic stability control and AEB systems to be on during vehicle operation.
Full Text
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<body><pre>[Federal Register Volume 88, Number 128 (Thursday, July 6, 2023)]
[Proposed Rules]
[Pages 43174-43246]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-13622]
[[Page 43173]]
Vol. 88
Thursday,
No. 128
July 6, 2023
Part II
Department of Transportation
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National Highway Traffic Safety Administration
Federal Motor Carrier Safety Administration
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49 CFR Parts 393, 396, 571, et al.
Heavy Vehicle Automatic Emergency Braking; AEB Test Devices; Notice of
Proposed Rule
Federal Register / Vol. 88, No. 128 / Thursday, July 6, 2023 /
Proposed Rules
[[Page 43174]]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Parts 571 and 596
[Docket No. NHTSA-2023-0023]
RIN 2127-AM36
Federal Motor Carrier Safety Administration
49 CFR Parts 393 and 396
[Docket No. FMCSA-2022-0171]
RIN 2126-AC49
Heavy Vehicle Automatic Emergency Braking; AEB Test Devices
AGENCY: National Highway Traffic Safety Administration (NHTSA), Federal
Motor Carrier Safety Administration (FMCSA), Department of
Transportation (DOT).
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This NPRM proposes to adopt a new Federal Motor Vehicle Safety
Standard (FMVSS) to require automatic emergency braking (AEB) systems
on heavy vehicles, i.e., vehicles with a gross vehicle weight rating
greater than 4,536 kilograms (10,000 pounds). This notice also proposes
to amend FMVSS No. 136 to require nearly all heavy vehicles to have an
electronic stability control system that meets the equipment
requirements, general system operational capability requirements, and
malfunction detection requirements of FMVSS No. 136. An AEB system uses
multiple sensor technologies and sub-systems that work together to
sense when the vehicle is in a crash imminent situation and
automatically applies the vehicle brakes if the driver has not done so
or automatically applies more braking force to supplement the driver's
applied braking. This NPRM follows NHTSA's 2015 grant of a petition for
rulemaking from the Truck Safety Coalition, the Center for Auto Safety,
Advocates for Highway and Auto Safety and Road Safe America, requesting
that NHTSA establish a safety standard to require AEB on certain heavy
vehicles. This NPRM also responds to a mandate under the Bipartisan
Infrastructure Law, as enacted as the Infrastructure Investment and
Jobs Act, directing the Department to prescribe an FMVSS that requires
heavy commercial vehicles with FMVSS-required electronic stability
control systems to be equipped with an AEB system, and also promotes
DOT's January 2022 National Roadway Safety Strategy to initiate a
rulemaking to require AEB on heavy trucks. This NPRM also proposes
Federal Motor Carrier Safety Regulations requiring the electronic
stability control and AEB systems to be on during vehicle operation.
DATES: Comments must be received on or before September 5, 2023.
Proposed compliance dates: NHTSA proposes a two-tiered phase-in
schedule for meeting the proposed standard. For vehicles currently
subject to FMVSS No. 136, ``Electronic stability control systems for
heavy vehicles,'' any vehicle manufactured on or after the first
September 1 that is three years after the date of publication of the
final rule would be required to meet the proposed heavy vehicle AEB
standard. For vehicles with a gross vehicle weight rating greater than
4,536 kilograms (10,000 pounds) not currently subject to FMVSS No. 136,
any vehicle manufactured on or after the first September 1 that is four
years after the date of publication of the final rule would be required
to meet the proposed AEB requirements and the proposed amendments to
the ESC requirements. Small-volume manufacturers, final-stage
manufacturers, and alterers would be provided an additional year to
comply with this proposal beyond the dates identified above.
FMCSA proposes that vehicles currently subject to FMVSS No. 136
would be required to comply with FMCSA's proposed ESC regulation on the
final rule's effective date. Vehicles with a GVWR greater than 4,536
kilograms (10,000 pounds) not currently subject to FMVSS No. 136 would
be required to meet the proposed ESC regulation on or after the first
September 1 that is five years after the date of publication of the
final rule.
FMCSA proposes that, for vehicles currently subject to FMVSS No.
136, any vehicle manufactured on or after the first September 1 that is
three years after the date of publication of the final rule would be
required to meet FMCSA's proposed AEB regulation. FMCSA proposes that
vehicles with a gross vehicle weight rating greater than 4,536
kilograms (10,000 pounds) not currently subject to FMVSS No. 136 and
vehicles supplied to motor carriers by small-volume manufacturers,
final-stage manufacturers, and alterers would be required to meet the
proposed AEB regulation on or after the first September 1 that is five
years after the date of publication of the final rule.
This proposed implementation timeframe simplifies FMCSR training
and enforcement because the Agency expects a large number of final
stage manufacturers supplying vehicles to motor carriers in the
category of vehicles with a gross vehicle weight rating greater than
4,536 kilograms (10,000 pounds).
FMCSA's phase-in schedule would require the ESC and AEB systems to
be inspected and maintained in accordance with Sec. 396.3.
Early compliance is permitted but optional.
ADDRESSES: You may submit comments to the docket number identified in
the heading of this document by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the online instructions for submitting
comments.
<bullet> Mail: Docket Management Facility, M-30, U.S. Department of
Transportation, West Building, Ground Floor, Rm. W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.
<bullet> Hand Delivery or Courier: West Building, Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE, between 9 a.m. and 5 p.m.
Eastern Time, Monday through Friday, except Federal holidays. To be
sure someone is there to help you, please call 202-366-9332 before
coming.
<bullet> Fax: 202-493-2251.
Regardless of how you submit your comments, please provide the
docket number of this document.
Instructions: For detailed instructions on submitting comments and
additional information on the rulemaking process, see the Public
Participation heading of the Supplementary Information section of this
document. Note that all comments received will be posted without change
to <a href="https://www.regulations.gov">https://www.regulations.gov</a>, including any personal information
provided.
Privacy Act: In accordance with 5 U.S.C. 553(c), DOT solicits
comments from the public to better inform its decision-making process.
DOT posts these comments, without edit, including any personal
information the commenter provides, to <a href="https://www.regulations.gov">https://www.regulations.gov</a>, as
described in the system of records notice (DOT/ALL-14 FDMS), which can
be reviewed at <a href="https://www.transportation.gov/privacy">https://www.transportation.gov/privacy</a>. In order to
facilitate comment tracking and response, the agency encourages
commenters to provide their name, or the name of their organization;
however, submission of names is completely optional. Whether or not
commenters identify themselves, all timely comments will be fully
considered.
Docket: For access to the docket to read background documents or
[[Page 43175]]
comments received, go to <a href="https://www.regulations.gov">https://www.regulations.gov</a>, or the street
address listed above. To be sure someone is there to help you, please
call 202-366-9322 before coming. Follow the online instructions for
accessing the dockets.
FOR FURTHER INFORMATION CONTACT: NHTSA: For non-legal issues: Hisham
Mohamed, Office of Crash Avoidance Standards (telephone: 202-366-0307).
For legal issues: David Jasinski, Office of the Chief Counsel
(telephone: 202-366-2992, fax: 202-366-3820). The mailing address for
these officials is: National Highway Traffic Safety Administration,
1200 New Jersey Avenue SE, Washington, DC 20590. FMCSA: For FMCSA
issues: David Sutula, Office of Vehicle and Roadside Operations
Division (telephone: 202-366-9209). The mailing address for this
official is: Federal Motor Carrier Safety Administration, 1200 New
Jersey Avenue SE, Washington, DC 20590.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Executive Summary
II. Safety Problem
III. Efforts To Promote AEB Deployment in Heavy Vehicles
A. NHTSA's Foundational AEB Research
B. NHTSA's 2015 Grant of a Petition for Rulemaking
C. Congressional Interest
1. MAP-21
2. Bipartisan Infrastructure Law
D. IIHS Effectiveness Study
E. DOT's National Roadway Safety Strategy (January 2022)
F. National Transportation Safety Board Recommendations
G. FMCSA Initiatives
IV. NHTSA and FMCSA Research and Testing
A. NHTSA-Sponsored Research
1. 2012 Study on Effectiveness of FCW and AEB
2. 2016 Field Study
3. 2017 Target Population Study
4. 2018 Cost and Weight Analysis
B. VRTC Research Report Summaries and Test Track Data
1. Relevance of Research Efforts on AEB for Light Vehicles
2. Phase I Testing of Class 8 Truck-Tractors and Motorcoach
3. Phase II Testing of Class 8 Truck-Tractors
4. NHTSA's 2018 Heavy Vehicle AEB Testing
5. NHTSA's Research Test Track Procedures
6. 2021 VRTC Testing
C. NHTSA Field Study of a New Generation Heavy Vehicle AEB
System
D. FMCSA-Sponsored Research
V. Need for This Proposed Rule and Guiding Principles
A. Estimating AEB System Effectiveness
B. AEB Performance Over a Range of Speeds Is Necessary and
Practicable
C. Market Penetration Varies Significantly Among Classes of
Heavy Vehicles
D. This NPRM Would Compel Improvements in AEB
E. BIL Section 23010(b)(2)(B)
F. Vehicles Excluded From Braking Requirements
VI. Heavy Vehicles Not Currently Subject to ESC Requirements
A. AEB and ESC Are Less Available on These Vehicles
B. This NPRM Proposes To Require ESC
C. BIL Section 23010(d)
D. Multi-Stage Vehicle Manufacturers and Alterers
VII. Proposed Performance Requirements
A. Proposed Requirements When Approaching a Lead Vehicle
1. Automatic Emergency Brake Application Requirements
2. Forward Collision Warning Requirement
i. FCW Modalities
ii. FCW Auditory Signal Characteristics
iii. FCW Visual Signal Characteristics
iv. FCW Haptic Signal Discussion
3. Performance Test Requirements
4. Performance Test Scenarios
i. Stopped Lead Vehicle
ii. Slower-Moving Lead Vehicle
iii. Decelerating Lead Vehicle
5. Parameters for Vehicle Tests
i. Vehicle Speed Parameters
ii. Headway
iii. Lead Vehicle Deceleration Parameter
6. Manual Brake Application in the Subject Vehicle
B. Conditions for Vehicle Tests
1. Environmental Conditions
2. Road Service Conditions
3. Subject Vehicle Conditions
C. Proposed Requirements for False Activation
1. No Automatic Braking Requirement
2. Vehicle Test Scenarios
i. Steel Trench Plate
ii. Pass-Through
D. Conditions for False Activation Tests
E. Potential Alternatives to False Activation Tests
F. Proposed Requirements for Malfunction Indication
G. Deactivation Switch
H. System Documentation
I. ESC Performance Test
J. Severability
VIII. Vehicle Test Device
A. Description and Development
B. Specifications
C. Alternatives Considered
IX. Proposed Compliance Date Schedule
X. Retrofitting
XI. Summary of Estimated Effectiveness, Cost, Benefits, and
Comparison of Regulatory Alternatives
A. Crash Problem
B. AEB System Effectiveness
C. ESC System Effectiveness
D. Avoided Crashes and Related Benefits
E. Technology Costs
F. Monetized Benefits
G. Alternatives
XII. Regulatory Notices and Analyses
XIII. Public Participation
XIV. Appendices to the Preamble
A. Description of Technologies
B. International Regulatory Requirements and Other Standards
Abbreviations Frequently Used in This Document
The following table is provided for the convenience of readers for
illustration purposes only.
Table 1--Abbreviations
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Abbreviation Full term Notes
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ABS................. Antilock Braking Automatically controls the
System. degree of longitudinal wheel
slip during braking to prevent
wheel lock and minimize
skidding by sensing the rate
of angular rotation of each
wheel and modulating the
braking force at the wheels to
keep the wheels from slipping.
AEB................. Automatic Applies a vehicle's brakes
Emergency automatically to avoid or
Braking. mitigate an impending forward
crash.
CIB................. Crash Imminent Applies automatic braking when
Braking. forward-looking sensors
indicate a crash is imminent
and the driver has not applied
the brakes.
CMV................. Commercial Motor Has the meaning given the term
Vehicle. in 49 U.S.C. 31101.
CRSS................ Crash Report A sample of police-reported
Sampling System. crashes involving all types of
motor vehicles, pedestrians,
and cyclists, ranging from
property-damage-only crashes
to those that result in
fatalities.
DBS................. Dynamic Brake Supplements the driver's
Support. application of the brake pedal
with additional braking when
sensors determine the driver-
applied braking is
insufficient to avoid an
imminent crash.
ESC................. Electronic Able to determine intended
Stability steering direction (steering
Control. wheel angle sensor), compare
it to the actual vehicle
direction, and then modulate
braking forces at each wheel
to induce a counter yaw when
the vehicle starts to lose
lateral stability.
FARS................ Fatality Analysis A nationwide census providing
Reporting System. annual data regarding fatal
injuries suffered in motor
vehicle crashes.
[[Page 43176]]
FCW................. Forward Collision An auditory and visual warning
Warning. provided to the vehicle
operator by the AEB system
that is designed to induce an
immediate forward crash
avoidance response by the
vehicle operator.
FMCSR............... Federal Motor 49 CFR parts 350-399.
Carrier Safety
Regulations.
FMVSS............... Federal Motor ...............................
Vehicle Safety
Standards.
GES................. General Estimates Data from a nationally
System. representative sample of
police reported motor vehicle
crashes of all types, from
minor to fatal.
GVWR................ Gross Vehicle The value specified by the
Weight Rating. manufacturer as the maximum
design loaded weight of a
single vehicle.
BIL................. Bipartisan Public Law 117-58 (Nov. 15,
Infrastructure 2021).
Law.
MAIS................ Maximum A means of describing injury
Abbreviated severity based on an ordinal
Injury Scale. scale. An MAIS 1 injury is a
minor injury and an MAIS 5
injury is a critical injury.
MAP-21.............. The Moving Ahead A funding and authorization
for Progress in bill to govern United States
the 21st Century Federal surface transportation
Act. spending. It was enacted into
law on July 6, 2012.
NCAP................ New Car ...............................
Assessment
Program.
PDO................. Property-damage- A police-reported crash
only. involving a motor vehicle in
transport on a trafficway in
which no one involved in the
crash suffered any injuries.
PDOV................ Property-Damage- Damaged vehicles involved in
Only-Vehicles. property-damage-only crashes.
TTC................. Time to collision The theoretical time, given the
current speed of the vehicles,
after which a rear-end
collision with the lead
vehicle would occur if no
corrective action was taken.
VRTC................ Vehicle Research NHTSA's in-house laboratory.
and Test Center.
VTD................. Vehicle Test A test device used to test AEB
Device. system performance.
------------------------------------------------------------------------
I. Executive Summary
There were 38,824 people killed in motor vehicle crashes on U.S.
roadways in 2020 and early estimates put the number of fatalities at
42,915 for 2021.\1\ The Department established the National Roadway
Safety Strategy in January 2022 to address this rising number of
transportation deaths occurring on this country's streets, roads, and
highways.\2\ This NPRM takes a crucial step in implementing this
strategy by proposing to adopt a new Federal motor vehicle safety
standard (FMVSS) that would require heavy vehicles to have automatic
emergency braking (AEB) systems that mitigate the frequency and
severity of rear-end collisions with vehicles.
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\1\ <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/813283">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813283</a>, https://www.nhtsa.gov/press-releases/early-estimate-2021-
traffic-
fatalities#:~:text=Preliminary%20data%20reported%20by%20the,from%201.
34%20fatalities%20in%202020.
\2\ <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>. Last accessed August
23, 2022.
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The crash problem addressed by heavy vehicle AEB is substantial, as
are the safety benefits to be gained. This NPRM addresses lead vehicle
rear-end, rollover, and loss of control crashes, and their associated
fatalities, injuries, and property damage. The NPRM also proposes new
Federal Motor Carrier Safety Regulations requiring the electronic
stability control and AEB systems to be on during vehicle operation.
Considering the effectiveness of AEB and electronic stability control
technology (ESC) at avoiding these crashes, the proposed rule would
conservatively prevent an estimated 19,118 crashes, save 155 lives, and
reduce 8,814 non-fatal injuries annually once all vehicles covered in
this rule are equipped with AEB and ESC. In addition, it would
eliminate 24,828 property-damage-only crashes annually.
In this NPRM, the term ``heavy vehicles'' refers to vehicles with a
gross vehicle weight rating (GVWR) greater than 4,536 kilograms (10,000
pounds). For application of the FMVSS, it is often necessary to further
categorize these heavy vehicles, as the FMVSS must be appropriate for
the particular type of motor vehicle for which they are
prescribed.<SUP>3 4</SUP> Certain vehicles have common characteristics
relevant to the application of AEB, and categorizing those vehicles
accordingly allows for useful analyses, proposals, or other
considerations that are particularly appropriate for the vehicle group
and application of the safety standards.
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\3\ As required by 49 U.S.C 30111(b)(3), NHTSA shall consider
whether a proposed standard is reasonable, practicable, and
appropriate for the particular type of motor vehicle or motor
vehicle equipment for which it is prescribed.
\4\ This NPRM excludes heavy trailers because they typically do
not have braking components necessary for AEB.
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One useful way to categorize vehicles further is by GVWR. This NPRM
uses vehicle class numbers designed by NHTSA in 49 CFR 565, ``Vehicle
identification number requirements,'' and the Federal Highway
Administration that are based on GVWR.\5\ These class numbers, shown in
Table 2 below, are widely used by industry and States in categorizing
vehicles. In this NPRM, ``heavy vehicle'' and ``class 3 through 8''
both refer to all vehicles with a GVWR greater than 4,536 kg (10,000
lbs.). The term ``class 3 through 6'' refers to vehicles with a GVWR
greater than 4,536 kg (10,000 lbs.) and up to 11,793 kg (26,000 lbs.),
while the term ``class 7 to 8'' refers to vehicles with a GVWR greater
than 11,793 kg (26,000 lbs.).
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\5\ See <a href="https://ops.fhwa.dot.gov/publications/fhwahop10014/s5.htm#f21">https://ops.fhwa.dot.gov/publications/fhwahop10014/s5.htm#f21</a> (Last viewed on May 5, 2022).
[[Page 43177]]
Table 2--Vehicle Class by GVWR
------------------------------------------------------------------------
Vehicle class GVWR
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1............................ Not greater than 2,722 kg (6,000 lbs.).
2a........................... Greater than 2,722 kg (6,000 lbs.) and up
to 3,856 kg (8,500 lbs.).
2b........................... Greater than 3,856 kg (8,500 lbs.) and up
to 4,536 kg (10,000 lbs.).
3............................ Greater than 4,536 kg (10,000 lbs.) and
up to 6,350 kg (14,000 lbs.).
4............................ Greater than 6,350 kg (14,000 lbs.) and
up to 7,257 kg (16,000 lbs.).
5............................ Greater than 7,257 kg (16,000 lbs.) and
up to 8,845 kg (19,500 lbs.).
6............................ Greater than 8,845 kg (19,500 lbs.) and
up to 11,793 kg (26,000 lbs.).
7............................ Greater than 11,793 kg (26,000 lbs.) and
up to 14,969 kg (33,000 lbs.).
8............................ Greater than 14,969 kg (33,000 lbs.).
------------------------------------------------------------------------
NHTSA and FMCSA have jointly developed this NPRM. Both agencies
will have complementary standards that respond to mandates in Section
23010 of the Bipartisan Infrastructure Law (BIL), as enacted as the
Infrastructure Investment and Jobs Act. Section 23010(b) requires the
Secretary to prescribe an FMVSS that requires any commercial motor
vehicle subject to FMVSS No. 136, ``Electronic stability control
systems for heavy vehicles,'' to be equipped with an AEB system meeting
performance requirements established in the new FMVSS not later than
two years after enactment. Section 23010(c) requires the Secretary to
prescribe a Federal Motor Carrier Safety Regulation (FMCSR) that
requires, for commercial motor vehicles subject to FMVSS No. 136, that
an AEB system installed pursuant to the new Federal motor vehicle
safety standard must be used at any time during which the commercial
motor vehicle is in operation. This NPRM sets forth NHTSA's proposed
FMVSS and FMCSA's proposed FMCSR issued pursuant to these provisions of
the BIL. In order to provide the benefits of AEB to a greater number of
vehicles, this proposal would also require that many heavy vehicles not
currently subject to FMVSS No. 136, including vehicles in classes 3
through 6, be equipped with ESC and AEB systems under the authority
provided in the Motor Vehicle Safety Act. Pursuant to section 23010(d)
of the BIL, NHTSA seeks public comment on this proposal.
NHTSA's Statutory Authority
NHTSA is proposing this NPRM under the National Traffic and Motor
Vehicle Safety Act (``Motor Vehicle Safety Act'') and in response to
the Bipartisan Infrastructure Law. Under 49 U.S.C. Chapter 301, Motor
Vehicle Safety (49 U.S.C. 30101 et seq.), 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. ``Motor vehicle safety'' is defined
in the Motor Vehicle Safety Act as ``the performance of a motor vehicle
or motor vehicle equipment in a way that protects the public against
unreasonable risk of accidents occurring because of the design,
construction, or performance of a motor vehicle, and against
unreasonable risk of death or injury in a crash, and includes
nonoperational safety of a motor vehicle.'' ``Motor vehicle safety
standard'' means a minimum performance standard for motor vehicles or
motor vehicle equipment. When prescribing such standards, the Secretary
must consider all relevant, available motor vehicle safety information.
The Secretary must also consider whether a proposed standard is
reasonable, practicable, and appropriate for the types of motor
vehicles or motor vehicle equipment for which it is prescribed and the
extent to which the standard will further the statutory purpose of
reducing traffic accidents and associated deaths. The responsibility
for promulgation of Federal motor vehicle safety standards is delegated
to NHTSA.
In developing this NPRM, NHTSA carefully considered these statutory
requirements, and relevant Executive Orders, Departmental Orders, and
administrative laws and procedures. NHTSA is also issuing this NPRM in
response to the Bipartisan Infrastructure Law. Section 23010 of BIL \6\
requires the Secretary to prescribe a Federal motor vehicle safety
standard to require all commercial motor vehicles subject to a
particular brake system standard to be equipped with an AEB system
meeting established performance requirements. BIL directs the Secretary
to prescribe the standard not later than two years after the date of
enactment of the Act.
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\6\ Public Law 117-58, (Nov. 15, 2021).
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FMCSA's Statutory Authority
For purposes of this NPRM, FMCSA's authority is found in the Motor
Carrier Act of 1935 (1935 Act, 49 U.S.C. 31502) and the Motor Carrier
Safety Act of 1984 (1984 Act, 49 U.S.C. 31132 et seq.), both as
amended. The authorities assigned to the Secretary in these two acts
are delegated to the FMCSA Administrator in 49 CFR 1.87(i) and (f),
respectively. In addition, section 23010(c) of the BIL, Public Law 117-
58, 135 Stat. 429, 766-767, Nov. 15, 2021, requires FMCSA to adopt an
AEB regulation consistent with the companion NHTSA AEB regulation.
The 1935 Act authorizes the DOT to ``prescribe requirements for--
(1) qualifications and maximum hours of service of employees of and
safety of operation and equipment of a motor carrier; and (2)
qualifications and maximum hours of service of employees of, and
standards of equipment of, a motor private carrier, when needed to
promote safety of operations'' (49 U.S.C. 31502(b)). FMCSA's proposed
ESC and AEB regulations, which incorporate the ESC and AEB requirements
of the NHTSA rule, will require most motor carriers to maintain and use
the ESC and AEB systems required by the corresponding NHTSA regulations
to promote safety of operations.
The 1984 Act confers on DOT the authority to regulate drivers,
motor carriers, and vehicle equipment. ``At a minimum, the regulations
shall ensure that--(1) commercial motor vehicles are maintained,
equipped, loaded, and operated safely; (2) the responsibilities imposed
on operators of commercial motor vehicles do not impair their ability
to operate the vehicles safely; (3) the physical condition of operators
of commercial motor vehicles is adequate to enable them to operate the
vehicles safely; (4) the operation of commercial motor vehicles does
not have a deleterious effect on the physical condition of the
operators; and (5) an operator of a commercial motor vehicle is not
coerced by a motor carrier, shipper, receiver, or transportation
intermediary to operate a commercial motor vehicle in violation of a
regulation promulgated under this section, or chapter 51 or chapter 313
of this title'' (49 U.S.C. 31136(a)(1)-(5)).
[[Page 43178]]
FMCSA's proposed rule will help to ensure that commercial motor
vehicles (CMVs) equipped with the ESC and AEB systems mandated by NHTSA
are maintained and operated safely, as required by 49 U.S.C.
31136(a)(1). While the FMCSA proposal does not explicitly address the
remaining provisions of section 31136, it will enhance the ability of
drivers to operate safely, consistent with 49 U.S.C. 31136(a)(2)-(4).
Section 23010(c) of BIL requires FMCSA to prescribe a regulation
under 49 U.S.C. 31136 that requires that an automatic emergency braking
system installed in a commercial motor vehicle manufactured after the
effective date of the NHTSA standard that is in operation on or after
that date and is subject to 49 CFR 571.136 be used at any time during
which the commercial motor vehicle is in operation'' (135 Stat. 767).
Consistent with the BIL mandate, part of FMCSA's proposal would require
that motor carriers operating CMVs manufactured subject to FMVSS No.
136 maintain and use the required AEB devices as prescribed by NHTSA
whenever the CMV is operating.
AEB and ESC Systems
An AEB system employs multiple sensor technologies and sub-systems
that work together to sense when a vehicle is in a crash imminent
situation with a lead vehicle and, when necessary, automatically apply
the vehicle brakes if the driver has not done so, or apply the brakes
to supplement the driver's applied braking. Current systems use radar
and camera-based sensors or combinations thereof. AEB builds upon older
forward collision warning-only systems. An FCW-only system provides an
alert to a driver of an impending rear-end collision with a lead
vehicle to induce the driver to take action to avoid the crash but does
not automatically apply the brakes. This proposal would require both
FCW and AEB systems. For simplicity, when referring to AEB systems in
general, this proposal is referring to both FCW and AEB unless the
context suggests otherwise.
This proposal follows up on NHTSA's October 16, 2015 notice
granting a petition for rulemaking submitted by the Truck Safety
Coalition, the Center for Auto Safety, Advocates for Highway and Auto
Safety, and Road Safe America.\7\ The petitioners requested that NHTSA
establish a safety standard to require automatic forward collision
avoidance and mitigation systems on heavy vehicles. This rulemaking
also addresses recommendations made to NHTSA by the National
Transportation Safety Board.
---------------------------------------------------------------------------
\7\ 80 FR 62487.
---------------------------------------------------------------------------
The safety problem addressed by AEB is substantial. An annualized
average of 2017 to 2019 data from NHTSA's Fatality Analysis Reporting
System (FARS) and the Crash Report Sampling System (CRSS) shows that
heavy vehicles are involved in around 60,000 rear-end crashes in which
the heavy vehicle was the striking vehicle annually, which represents
11 percent of all crashes involving heavy vehicles.\8\ These rear-end
crashes resulted in 388 fatalities annually, which comprises 7.4
percent of all fatalities in heavy vehicle crashes. These crashes
resulted in approximately 30,000 injuries annually, or 14.4 percent of
all injuries in heavy vehicle crashes, and 84,000 damaged vehicles with
no injuries or fatalities.
---------------------------------------------------------------------------
\8\ These rear-end crashes are cases where the heavy vehicle was
the striking vehicle.
---------------------------------------------------------------------------
Considering vehicle size, approximately half of the rear-end
crashes, injuries, and fatalities resulting from rear-end crashes where
the heavy vehicle was the striking vehicle involved vehicles with a
gross vehicle weight rating above 4,536 kilograms (10,000 pounds) up to
11,793 kilograms (26,000 pounds). Similarly, half of all rear-end
crashes and the fatalities and injuries resulting from those crashes
where the heavy vehicle was the striking vehicle involved vehicles with
a gross vehicle weight rating of greater than 11.793 kilograms (26,000
pounds).
The speed of the striking vehicle is an important factor in the
severity of a crash. For example, in approximately 53 percent of
crashes, the striking vehicle was traveling at or under 30 mph (47 km/
h). Those crashes, though, were responsible for only approximately 1
percent of fatalities. In contrast, in approximately 17 percent of
crashes, the striking vehicle was traveling over 55 mph (89 km/h).
Those crashes resulted in 89 percent of the fatalities from rear-end
crashes involving heavy vehicles. While the majority of crashes occur
at low speeds, the overwhelming majority of fatalities result from
high-speed crashes. For AEB systems to address this safety problem,
they must function at both low and high speeds.
NHTSA has been studying AEB technologies since their conception
over 15 years ago. NHTSA and FMCSA have recognized the potential of
heavy vehicle AEB for many years and continued to research this
technology as it evolved from early generations to its current state.
As part of NHTSA's efforts to better understand these new collision
prevention technologies, NHTSA sponsored and conducted numerous
research projects, including ones focused on AEB and FCW for heavy
trucks. NHTSA conducted testing at its in-house testing facility, the
Vehicle Research and Test Center, to examine the effectiveness of AEB
in different crash scenarios and speeds. NHTSA and FMCSA have also
sponsored or conducted projects with a specific focus on the heavy
vehicle rear-end crash problem.
International standards for the regulation of AEB systems on heavy
vehicles exist and are under development. The European Union and Asian
countries have either already adopted or are considering AEB
regulations for heavy vehicles. More information can be found in
Appendix A of this document.
In 2016, NHTSA published its first report of track testing of heavy
vehicles equipped with AEB systems. NHTSA used its light vehicle test
procedures, similar to those used in NHTSA's New Car Assessment
Program,\9\ as a framework to adapt for use on heavy vehicles. These
scenarios included a stopped lead vehicle scenario, a slower moving
lead vehicle scenario, a decelerating lead vehicle scenario, and a
false positive scenario that consisted of driving over a steel trench
plate. NHTSA's initial testing of AEB systems focused on vehicles
equipped with ESC--primarily Class 8 truck tractors and motorcoaches.
Adjustments had to be made to the scenarios to account for the greater
stopping distances of heavy vehicles compared to light vehicles and to
the surrogate vehicle and towing device to ensure that the systems
performed as they would on the road. Testing of early heavy vehicle
systems indicated that vehicles did not automatically brake when
encountering a stopped lead vehicle. The false positive test also
resulted in FCW alerts, but no automatic braking.
---------------------------------------------------------------------------
\9\ NHTSA's New Car Assessment Program (NCAP) provides
comparative information on the safety performance of new vehicles to
assist consumers with vehicle purchasing decisions and to encourage
safety improvements.
---------------------------------------------------------------------------
Later testing was intended to evaluate the evolution of AEB
systems, to further refine the test procedures, and to test other
vehicle types such as single-unit trucks and class 3 through 6
vehicles. Newer FCW and AEB systems on heavy vehicles generally
performed better than older versions. Testing of these updated systems
exhibited less severe rear-end collisions through velocity reductions
before a collision or avoided contact with a lead vehicle entirely. The
refined test procedures addressed previous
[[Page 43179]]
issues with timing, range parameters, and the vehicle test device.
NHTSA's most recent testing of a 2021 Freightliner Cascadia, a
class 8 truck tractor, indicated that the AEB system was able to
prevent a collision with a lead vehicle at speeds between 40 km/h and
85 km/h. Collisions occurred with the lead vehicle at lower speeds,
although significant speed reductions were still achieved. This
suggests that collision avoidance at lower speed cannot necessarily be
extrapolated to performance outcomes at higher speed and may depend on
the specific ways AEB systems may be programmed. It also indicates that
AEB systems that prevent collisions at higher speeds are practicable.
NHTSA and FMCSA studies have also examined system availability
across all types of heavy vehicles. Across larger (class 7 and 8) air
braked truck tractors and motorcoaches, AEB systems are widely
available. A market analysis of class 3 through 6 heavy vehicles showed
that nearly all manufacturers had at least one vehicle model within
each class available with AEB. Two manufacturers had AEB advertised as
standard equipment on at least one model. All vehicles that were
offered with AEB systems were also equipped with ESC systems. A few
models that offered FCW-only systems (not capable of automatic brake
application) did so without also having ESC.
Based on these factors, and consistent with the Motor Vehicle
Safety Act and the BIL, NHTSA is proposing a new FMVSS that would
require nearly all heavy vehicles to be equipped with AEB systems.\10\
Furthermore, FMCSA is proposing that all commercial vehicles equipped
with ESC and AEB systems required by NHTSA's proposed rule be used any
time the commercial vehicle is in operation. NHTSA is further proposing
minimum performance criteria for AEB systems to meet the need for
safety. These performance criteria would ensure that AEB systems
function at a wide range of speeds that address the safety problem
associated with rear-end crashes, injuries, and fatalities.
---------------------------------------------------------------------------
\10\ The vehicles excluded from this proposal include trailers,
which by definition, are towed by other vehicles, and vehicles
already excluded from NHTSA's braking requirements. For details, see
section V.F.
---------------------------------------------------------------------------
Based on NHTSA's survey of publicly available data on ESC and AEB
system availability, all manufacturers that have equipped vehicles with
AEB systems (other than FCW-only systems) have done so only if the
vehicle is also equipped with an ESC system. Furthermore, NHTSA has
consulted with two AEB system manufacturers for heavy vehicles and both
indicated that they would equip vehicles with AEB only if they were
also equipped with ESC.\11\ An ESC system provides stability under
braking by using differential braking and engine torque reduction to
reduce lateral instability that could induce rollover or loss of
directional control. An ABS system also provides lateral stability
under braking. ABS systems are currently required on all vehicles
subject to this proposal under FMVSS Nos. 105 and 121. However, the
absence of any AEB systems available without ESC leads NHTSA to believe
that manufacturers have identified scenarios in which the operation of
an AEB system without ESC may have adverse safety effects that are not
adequately addressed by ABS systems alone.
---------------------------------------------------------------------------
\11\ On September 29, 2021, NHTSA met with Daimler Truck North
America (DTNA) and on October 22, 2021, NHTSA met with Bendix to
discuss the AEB systems of heavy vehicles.
---------------------------------------------------------------------------
Summary of the Proposal
NHTSA has tentatively concluded based upon this information that a
safety need exists for an ESC system to be installed on a vehicle
equipped with AEB. Consequently, this proposal also requires nearly all
heavy vehicles to be equipped with an ESC system.\12\ Even separate
from the benefits of AEB, the safety problem related to the vehicles
addressed by the FMVSS No. 136 amendments is also substantial. Class 3
through 6 heavy vehicles are involved in approximately 17,000 rollover
and loss of control crashes annually. These crashes resulted in 178
fatalities annually, approximately 4,000 non-fatal injuries, and 13,000
damaged vehicles. Currently, pursuant to FMVSS No. 136, only class 7
and 8 truck tractors and certain large buses are required to have ESC
systems. FMVSS No. 136 includes both vehicle equipment requirements and
performance requirements. This proposal would amend FMVSS No. 136 to
require nearly all heavy vehicles to have an ESC system that meets the
equipment requirements, the general system operational capability
requirements, and malfunction detection requirements of FMVSS No. 136.
It would not, as proposed, require vehicles not currently required to
have ESC systems to meet any test track performance requirements for
ESC systems, though the agency does request comment on whether to
include a performance test and, if so, what that test should be. In
designing any potential test, NHTSA wishes to remain conscious of the
potential testing burden on small businesses and the multi-stage
vehicle manufacturers.
---------------------------------------------------------------------------
\12\ The vehicles excluded from the proposed ESC requirements
are the same vehicles excluded from the proposed AEB requirements.
---------------------------------------------------------------------------
The proposed standard includes certain requirements for AEB
systems. First, vehicles would be required to provide the driver with a
forward collision warning at any forward speed greater than 10 km/h
(6.2 mph). NHTSA is proposing that the forward collision warning be
auditory and visual with limited specifications for each of the warning
modalities. NHTSA has tentatively concluded that no further
specification of the warning is necessary.
Second, vehicles would be required to have an AEB system that
applies the service brakes automatically at any forward speed greater
than 10 km/h (6.2 mph) when a collision with a lead vehicle is
imminent. This requirement serves to ensure that AEB systems operate at
all speeds above 10 km/h, even if they are above the speeds tested by
NHTSA. This requirement also assures at least some level of AEB system
performance in rear-end crashes other than those for which NHTSA has
test procedures.
Third, the AEB system would be required to prevent the vehicle from
colliding with a lead vehicle when tested according to the proposed
standard's test procedures. Vehicles with AEB systems meeting the
proposed standard would have to automatically activate the braking
system when they encounter a stopped lead vehicle, a slower moving lead
vehicle, or a decelerating lead vehicle.
The proposed requirements also include two tests to ensure that the
AEB system does not inappropriately activate when no collision is
actually imminent. These false positive tests provide some assurance
that an AEB system is capable of differentiating between an actual
imminent collision and a non-threat. While these tests are not
comprehensive, they establish a minimum performance for non-activation
of AEB systems. The two scenarios NHTSA proposes to test are driving
over a steel trench plate and driving between two parked vehicles.
The final proposed requirement for AEB systems is that they be
capable of detecting a system malfunction and notify the driver of any
malfunction that causes the AEB system not to operate. This proposed
requirement would include any malfunction solely attributable to sensor
obstruction, such as by accumulated snow or debris, dense fog, or
sunlight glare. The malfunction telltale must remain active as long as
the malfunction exists, and
[[Page 43180]]
the vehicle's starting system is on. The proposal does not include any
specifications for the form of this notification to the driver.
The NPRM also includes proposed test procedures. In this NPRM, the
heavy vehicle being evaluated with AEB is referred to as the ``subject
vehicle.'' Other vehicles involved in the test are referred to as
``vehicle test devices,'' (VTDs) and a specific type of VTD called the
``lead vehicle'' refers to a vehicle which is ahead in the same lane,
in the path of the moving subject vehicle. To ensure repeatable test
conduct that reflects how a subject vehicle might respond in the real
world, this proposal includes broad specifications for a vehicle test
device to be used as a lead vehicle or principal other vehicle during
testing. NHTSA is proposing that the vehicle test device is based on
the specifications in the International Organization for
Standardization (ISO) standard 19206-3:2021.\13\ The vehicle test
device is a tool that NHTSA would use in the agency's compliance tests
to measure the performance of automatic emergency braking systems
required by the FMVSS. For its research testing, NHTSA has been using a
full-size surrogate vehicle, the Global Vehicle Target (GVT). The GVT
falls within the specifications of ISO 19206-3:2021. These
specifications include specifications for the dimensions, color and
reflectivity, and the radar cross section of a vehicle test device that
ensure it appears like a real vehicle to vehicle sensors.
---------------------------------------------------------------------------
\13\ ISO 19206-3:2021, ``Road vehicles--Test devices for target
vehicles, vulnerable road users and other objects, for assessment of
active safety functions--Part 3: Requirements for passenger vehicle
3D targets.'' <a href="https://www.iso.org/standard/70133.html">https://www.iso.org/standard/70133.html</a>. May 2021.
---------------------------------------------------------------------------
NHTSA has included three test scenarios in this proposed rule for
AEB when approaching a lead vehicle--a stopped lead vehicle, a slower
moving lead vehicle, and a decelerating lead vehicle. The stopped lead
vehicle scenario consists of the subject vehicle--that is, the vehicle
being tested--traveling straight at a constant speed approaching a
stopped lead vehicle in the center of its path. To satisfy the proposed
performance requirement, the subject vehicle must provide an FCW and
stop prior to colliding with the lead vehicle. NHTSA proposes to
conduct this scenario both with no manual brake application and with
manual brake application. Testing with manual brake application is
similar to the DBS test procedure that is included in New Car
Assessment Program for light vehicles. While DBS is not generally
advertised as a feature of AEB systems on air braked vehicles, driver-
applied braking should not suppress automatic braking. Testing without
manual brake application would be conducted at any constant speed
between 10 km/h and 80 km/h. The 80 km/h upper bound of testing
reflects safety limitations that would result from any collision
resulting from a failure of an AEB system to activate in the testing
environment. However, with manual brake application, NHTSA proposes to
test vehicles up to 100 km/h. This is possible because the manual brake
application ensures at least some level of speed reduction even in a
test failure where automatic braking does not occur.
The second test scenario is a slower moving lead vehicle. In this
scenario, the subject vehicle is traveling straight at a constant
speed, approaching a lead vehicle traveling at a slower speed in the
subject vehicle's path. To satisfy the proposed performance test
requirement, the subject vehicle must provide an FCW and slow to a
speed equal to or below the lead vehicle's speed without colliding with
the lead vehicle. As with the stopped lead vehicle test, NHTSA proposes
to perform this test with both no manual brake application and manual
brake application. The subject vehicle speed without manual brake
application would be any constant speed between 40 km/h and 80 km/h,
and with manual brake application, testing would be conducted at any
constant speed between 70 km/h and 100 km/h. The lead vehicle would
travel at 20 km/h in all tests.
The third test scenario is a decelerating lead vehicle. In this
scenario, the subject vehicle and lead vehicle are travelling at the
same constant speed in the same path and the lead vehicle begins to
decelerate. To satisfy the proposed performance test requirement, the
subject vehicle must provide an FCW and stop without colliding with the
lead vehicle. As with the other AEB tests approaching a lead vehicle,
this test is performed both with and without manual brake application.
However, the test speeds are the same for both scenarios--either 50 km/
h or 80 km/h. The lead vehicle would decelerate with a magnitude
between 0.3g and 0.4g and the headway between the vehicles would be any
distance between 21 m and 40 m (for 50 km/h tests) or 28 m and 40 m
(for 80 km/h tests). The upper bound of the lead vehicle deceleration
and the lower bound of the headway were chosen to ensure that the
corresponding test scenarios would not require a brake performance
beyond what is necessary to satisfy the minimum stopping distance
requirements in the FMVSS applicable to brake performance.
This proposal would require that all of the NHTSA AEB requirements
be phased in within four years of publication of a final rule. Truck
tractors and certain large buses with a GVWR of greater than 11,793
kilograms (26,000 pounds) that are currently subject to FMVSS No. 136
would be required to meet all requirements within three years. Vehicles
not currently subject to FMVSS No. 136 would be required to have ESC
and AEB systems within four years of publication of a final rule.
Small-volume manufacturers, final-stage manufacturers, and alterers
would be allowed one additional year (five years total) of lead time.
Consistent with the BIL mandate, FMCSA proposes to require that
motor carriers operating CMVs manufactured subject to FMVSS No. 136,
maintain and use the required AEB and ESC systems as prescribed by
NHTSA for the effective life of the CMV. FMCSA's proposed rule is
intended to ensure that commercial motor vehicles equipped with the ESC
and AEB systems mandated by NHTSA are maintained and operated safely,
as required by 49 U.S.C. 31136(a)(1). While the FMCSA proposal does not
explicitly address the remaining provisions of section 31136, it will
enhance the ability of drivers to operate safely, consistent with 49
U.S.C. 31136(a)(2)-(4). FMCSA's proposal would require the ESC and AEB
systems to be inspected and maintained in accordance with 49 CFR part
396, Inspection, Repair, and Maintenance (Sec. 396.3).
The proposed requirements would ensure that the benefits resulting
from CMVs equipped with ESC and AEB systems are sustained through
proper maintenance and operation. The maintenance costs include annual
costs required to keep the ESC and AEB systems operative. FMCSA
believes the cost of maintaining the ESC and AEB systems over their
lifetimes is minimal compared to the cost of equipping trucks with ESC
and AEB systems and may be covered by regular annual maintenance.
NHTSA and FMCSA have jointly determined not to propose retrofitting
requirements AEB for existing heavy vehicles and ESC for vehicles not
currently subject to FMVSS No. 136. For technical reasons, AEB and ESC
retrofits are difficult to apply broadly, generically, or inexpensively
and thus this NPRM does not propose a retrofit requirement.
NHTSA and FMCSA seek comments and suggestions on any aspect of this
[[Page 43181]]
proposal and any alternative requirements to address this safety
problem. NHTSA and FMCSA also request comments on the proposed lead
time for meeting these requirements, and how the lead time can be
structured to maximize the benefits that can be realized most quickly
while ensuring that the standard is practicable. Finally, NHTSA and
FMCSA seek comment on whether and how this proposal may
disproportionately impact small businesses and how NHTSA and FMCSA
could revise this proposal to minimize any disproportionate impact.
Benefits and Costs
NHTSA and FMCSA have issued a Preliminary Regulatory Impact
Analysis (PRIA) that analyzes the potential impacts of this proposed
rule. The PRIA is available in the docket for this NPRM.\14\ This
proposed rule is expected to substantially decrease risks associated
with rear-end, rollover, and loss of control crashes. The effectiveness
of AEB and ESC at avoiding rear-end, rollover, and loss of control
crashes is summarized in Table 3 for AEB and Table 4 for ESC.
---------------------------------------------------------------------------
\14\ The PRIA may be obtained by downloading it or by contacting
Docket Management at the address or telephone number provided at the
beginning of this document.
Table 3--AEB Effectiveness (%) by Vehicle Class Range and Crash Scenario
----------------------------------------------------------------------------------------------------------------
Stopped lead Slower-moving lead Decelerating lead
Vehicle class range vehicle vehicle vehicle
----------------------------------------------------------------------------------------------------------------
7-8................................................. 38.5 49.2 49.2
3-6................................................. 43.0 47.8 47.8
----------------------------------------------------------------------------------------------------------------
Table 4--ESC Effectiveness (%) by Crash Scenario
------------------------------------------------------------------------
Vehicle class range Rollover Loss of control
------------------------------------------------------------------------
3-6........................... 48.0 14.0
------------------------------------------------------------------------
Considering the annual rear-end, rollover, and loss of control
crashes, as well as the effectiveness of AEB and ESC at avoiding these
crashes, the proposed rule would prevent an estimated 19,118 crashes,
save 155 lives, and reduce 8,814 non-fatal injuries, annually. In
addition, the proposed rule would eliminate an estimated 24,828
property-damage-only-vehicles (PDOVs), annually. Table 5 shows these
estimated benefits also by vehicle class and technology.
Table 5--Estimated Annual Benefits of the Proposed Rule
----------------------------------------------------------------------------------------------------------------
Non-fatal
Crashes Fatalities injuries PDOVs avoided
avoided avoided avoided
----------------------------------------------------------------------------------------------------------------
By Vehicle Class
----------------------------------------------------------------------------------------------------------------
Class 7-8....................................... 5,691 40 2,822 7,958
Class 3-6....................................... 13,427 115 5,992 16,870
---------------------------------------------------------------
Total....................................... 19,118 155 8,814 24,828
----------------------------------------------------------------------------------------------------------------
By Technology
----------------------------------------------------------------------------------------------------------------
AEB............................................. 16,224 106 8,058 22,713
ESC............................................. 2,894 49 756 2,115
---------------------------------------------------------------
Total....................................... 19,118 155 8,814 24,828
----------------------------------------------------------------------------------------------------------------
There are two potential unintended consequences that cannot be
quantified: the impact of false activations on safety and the potential
impact of sensor degradation over time on AEB performance. However, the
required malfunction indicator combined with FMCSA's proposed AEB and
ESC inspection and maintenance requirements would help vehicle
operators maintain AEB systems and substantially reduce degradation of
AEB sensor performance. We seek comments on these two issues and ask
for any data that can help us to quantify these impacts.
The benefits estimate includes assumptions that likely result in
the underestimation of the benefits of this proposal because it does
not quantify the benefits from crash mitigation. That is, the benefits
only reflect those resulting from crashes that are avoided as a result
of AEB and ESC. It is likely that AEB will also reduce the severity of
crashes that are not prevented. Some of these crashes mitigated may
include fatalities and significant injuries that will be prevented or
mitigated by AEB. Finally, this NPRM does not quantify any potential
benefits that AEB could provide during adverse environmental conditions
(night, wet, etc.). While AEB is likely to be effective in many of
these crashes, NHTSA is not aware of any data to quantify the
performance degradation of AEB in adverse conditions.
The benefits of this proposed rule, monetized and analyzed with the
total annual cost, are summarized in Table 6. The total annual cost,
considering the implementation of both AEB and ESC technologies
proposed in this rule, is
[[Page 43182]]
estimated to be $353 million. The proposed rule would generate a net
benefit of $2.58 to $1.81 billion, annually under 3 and 7 percent
discount rates. The proposed rule would be cost-effective given that
the highest estimated net cost per fatal equivalent would be $0.50
million. Maintenance costs are considered de minimis and therefore not
included in the cost estimate.
Table 6--Estimated Annual Cost, Monetized Benefits, Cost-Effectiveness, and Net Benefits of the Proposed Rule
[2021 Dollars in millions]
----------------------------------------------------------------------------------------------------------------
Monetized Net cost per
Discount rates Annual cost * benefits fatal equivalent Net benefits
----------------------------------------------------------------------------------------------------------------
3 Percent.................................... $353.3 $2,937.0 \15\ -$0.12 $2,583.7
7 Percent.................................... 353.3 2,158.0 0.50 1,807.1
----------------------------------------------------------------------------------------------------------------
* Paid at purchasing; no need to discount.
NHTSA has issued an NPRM that proposes to adopt an FMVSS for AEB
requirements for light vehicles, including pedestrian AEB. \16\ NHTSA
notes that it may decide to issue final rules adopting the AEB
requirements for light and heavy vehicles in a way that incorporates
the AEB requirements into a single Federal motor vehicle safety
standard for all vehicle classes.
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\15\ The negative net cost per fatal equivalent reflects the
fact that savings from reducing traffic congestion and damaged
property is greater the total compliance costs of the proposed rule.
\16\ 88 FR 38632 (June 13, 2023).
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The following is a brief explanation of terms and technologies used
to describe AEB systems. More detailed information can be found in
Appendix A to this preamble.
Radar-Based Sensors
Heavy vehicle AEB systems typically employ radar sensors. At its
simplest, radar is a time-of-flight sensor that measures the time
between when a radio wave is transmitted and its reflection is
recorded. This time-of-flight is then used to calculate how far away
the object is that caused the reflection. Information about the
reflecting object, such as the speed at which it is travelling, can
also be determined. Radar units are compact, relatively easy to mount,
and do not require a line of sight to function properly. Radar can
penetrate most rubbers and plastics, allowing for the units to be
installed behind grilles and bumper fascia, increasing mounting
options. Radar can detect objects in low-light situations and also
works well in environmental conditions like precipitation and fog.
Camera Sensors
Cameras are passive sensors in which optical data are recorded then
processed to allow for object detection and classification. Cameras are
an important part of many automotive AEB systems, and one or more
cameras are typically mounted behind the front windshield and often up
high near the rearview mirror. Cameras at this location provide a good
view of the road and are protected by the windshield from debris,
grease, dirt, and other contaminants that can cover the sensor. Systems
that utilize two or more cameras can see stereoscopically, allowing the
processing system to determine range information along with detection
and classification.
Electronically Modulated Braking Systems
Automatic actuation of the vehicle brakes requires more than just
systems to sense when a collision is imminent. In addition to the
sensing system, hardware is needed to physically apply the brakes
without relying on the driver to apply the brake pedal. AEB leverages
two foundational braking technologies, antilock braking systems (ABS)
and electronic stability control. AEB uses the hardware equipped for
ESC and electronically applies the brakes to avoid certain scenarios
where a crash with a vehicle is imminent.
ABS: Antilock braking systems automatically control the degree of
longitudinal wheel slip during braking to prevent wheel lock and
minimize skidding by sensing the rate of angular rotation of the wheels
and modulating the braking force at the wheels to keep the wheels from
locking. Preventing wheel lock, and therefore skidding, greatly
increases the controllability of the vehicle during a panic stop.
Modern ABS systems have wheel speed sensors, independent brake
modulation at each wheel, and can increase or decrease braking
pressures as needed. During modulation of a brake application, the ABS
system repeatedly relieves and regenerates pressure to quickly release
and reapply, or ``pulse,'' the brake.
ESC: ESC builds upon the antilock brakes system by adding two
sensors, a steering wheel angle sensor and an inertial measurement
unit. These sensors allow the ESC controller to determine intended
steering direction (steering wheel angle sensor), compare it to the
actual vehicle direction, and then modulate braking forces at each
wheel to induce a corrective yaw moment when the vehicle starts to lose
lateral stability. An ESC system can control the brakes even when the
vehicle operator is not pressing the brake pedal.
When an AEB system activates in response to an imminent collision,
much of the same or similar hardware from ESC systems is used to
automatically control and modulate the brakes. Like ESC, an AEB system
includes components that give the vehicle the capacity to automatically
apply the brakes even when the vehicle operator is not pressing the
brake pedal. To do this in hydraulic brake systems, hydraulic brake
pressure is generated by a pump similarly as with ABS. In a pneumatic
brake system, the air pressure is already available via the air
reservoir and air compressor, and the ESC system must direct this
pressure accordingly. Additionally, the safety benefits of ESC enable
an AEB system to operate at its potential. Especially under the high-
speed, heavy-deceleration emergency braking events that potentially
occur during AEB activation, ESC could improve vehicle stability and
reduce the propensity for loss of control or rollover crashes that may
result from a steering response to an impending rear-end collision.
Forward Collision Warning
A forward collision warning (FCW) system uses the camera and radar
sensors described above, and couples them with an alert mechanism. An
FCW system can monitor a vehicle's speed, the speed of the vehicle in
front of it, and the distance between the two vehicles. If the FCW
system determines that the distance from the driver's vehicle to the
vehicle in front of it is too short, and the closing velocity between
[[Page 43183]]
the two vehicles too high, the system warns the driver of an impending
rear-end collision. Warning systems in use today provide drivers with a
visual display, such as a light on the instrument panel, an auditory
signal (e.g., beeping tone or chime), and/or a haptic signal that
provides tactile feedback to the driver (e.g., rapid vibrations of the
seat pan or steering wheel or a momentary brake pulse) to alert the
driver of an impending crash so they may manually intervene. The alerts
provided by FCW systems, even those that include momentary brake
pulses, are not intended to provide significant and sustained vehicle
deceleration. Rather, the FCW system is intended to inform the driver
that they must take corrective action in certain rear-end crash-
imminent driving situations.
Automatic Emergency Braking
An automatic emergency braking system automatically applies the
brakes to help drivers avoid or mitigate the severity of rear-end
crashes. AEB has two primary functions, crash imminent braking (CIB)
and a brake support system that supplements a driver's applied braking,
which is referred to as dynamic brake support (DBS) in the light
vehicle context. CIB systems apply automatic braking when forward-
looking sensors indicate a crash is imminent and the driver has not
applied the brakes, while supplemental brake support systems use the
same forward-looking sensors, but also supplement the driver's
application of the brake pedal with enhanced braking when sensors
determine the driver-applied braking is insufficient to avoid the
imminent crash. This NPRM does not split the terminology of these CIB
and supplemental brake support functionalities, and instead considers
both functions as part of AEB. The proposed standard includes
performance tests that would entail installation of AEB that has both
CIB and supplemental brake support functionalities.
``AEB'' as Used in This NPRM
As used in this NPRM, when we refer to ``AEB,'' we mean a system
that has: (a) a forward collision warning (FCW) component to alert the
driver to an impending collision; (b) a crash imminent braking
component (CIB) that automatically applies the vehicle's brakes if the
driver does not respond to an imminent crash in the forward direction
regardless of whether there's an FCW alert; and, (c) a supplemental
brake support component that automatically supplements the driver's
brake application if the driver applies insufficient manual braking.
II. Safety Problem
Overview
There were 38,824 people killed in motor vehicle crashes on U.S.
roadways in 2020 and 42,939 in 2021.<SUP>17 18</SUP> The 2021 data are
the highest numbers of fatalities since 2005. While the upward trend in
fatalities may be related to increases in risky driving behaviors
during the COVID-19 pandemic,\19\ NHTSA data from 2010 to 2019 show an
increase of approximately 3,000 fatalities since 2010. There has also
been an upward trend since 2010 in the total number of motor vehicle
crashes, which corresponds to an increase in fatalities, injuries, and
property damage. NHTSA uses data from its FARS and the CRSS, to account
for and understand motor vehicle crashes.\20\
---------------------------------------------------------------------------
\17\ <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813266">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813266</a>;, https://www.nhtsa.gov/press-releases/early-
estimate-2021-traffic-
fatalities#:~:text=Preliminary%20data%20reported%20by%20the,from%201.
34%20fatalities%20in%202020.
\18\ <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813435">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813435</a>; <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813283">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813283</a>; https://www.nhtsa.gov/press-releases/early-
estimate-2021-traffic-
fatalities#:~:text=Preliminary%20data%20reported%20by%20the,from%201.
34%20fatalities%20in%202020.
\19\ These behaviors relate to increases in impaired driving,
the non-use of seat belts, and speeding.
\20\ The Crash Report Sampling System (CRSS) builds on a
previous, long-running National Automotive Sampling System General
Estimates System (NASS GES). CRSS is a sample of police-reported
crashes involving all types of motor vehicles, pedestrians, and
cyclists, ranging from property-damage-only crashes to those that
result in fatalities. CRSS is used to estimate the overall crash
picture, identify highway safety problem areas, measure trends,
drive consumer information initiatives, and form the basis for cost
and benefit analyses of highway safety initiatives and regulations.
FARS contains data on every fatal motor vehicle traffic crash within
the 50 States, the District of Columbia, and Puerto Rico. To be
included in FARS, a traffic crash must involve a motor vehicle
traveling on a public trafficway that results in the death of a
vehicle occupant or a nonoccupant within 30 days of the crash.
---------------------------------------------------------------------------
Rear-End 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 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.\21\
---------------------------------------------------------------------------
\21\ <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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Heavy Vehicle Rear-End Crashes
On average from 2017 to 2019, there were 6.65 million annual
police-reported crashes resulting in 36,888 fatalities. Of the police-
reported crashes, approximately 550,000 involved a heavy vehicle (a
vehicle with a GVWR greater than 4,536 kg (10,000 pounds)), resulting
in 5,255 fatalities.\22\ Thus, heavy vehicle crashes represented 8.3
percent of the total number of crashes and resulted in 14.2 percent of
all fatalities. Annually, the entire U.S. fleet traveled a total of
3,237,449 million miles, and 9.3 percent of total vehicle miles
traveled were in heavy vehicles.\23\
---------------------------------------------------------------------------
\22\ Data are from 2017-2019 FARS and CRSS crash databases, as
discussed in the accompanying PRIA.
\23\ See the Traffic Safety Report at <a href="https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141">https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141</a> (Last
viewed September 22, 2022).
---------------------------------------------------------------------------
A typical heavy vehicle rear-end crash is characterized by a heavy
vehicle travelling on a roadway and colliding with another vehicle
ahead of it travelling in the same direction, but which is stopped,
moving slower, or decelerating, usually within the same lane. While
these crashes occur nationwide on all types of roads and in all
environments, they overwhelmingly take place on straight roadways (99
percent) and in dry conditions (85 percent). Approximately 60,000 (11
percent of heavy vehicle crashes annually), were rear-end crashes in
which the heavy vehicle was the striking vehicle. These rear-end
crashes resulted in 388 fatalities annually (7.4 percent of all
fatalities in heavy vehicle crashes), approximately 30,000 injuries
(14.3 percent of injuries in all heavy vehicle crashes.), and
approximately 84,000 damaged vehicles (without injuries or
fatalities).\24\
---------------------------------------------------------------------------
\24\ All data in this paragraph are from 2017-2019 FARS and CRSS
crash databases, and are discussed in the accompanying PRIA.
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The PRIA accompanying this proposal includes a complete review and
analysis of the relevant crash data and provides full details about the
target population of this NPRM. A summary of the PRIA is contained in
section XI. of this proposal.
Rear-End Crashes by Heavy Vehicle Class
Installing AEB on vehicles is related to the installation of ESC on
vehicles. ESC is required by FMVSS No. 136 for truck tractors and
certain large buses with a GVWR greater than 11,793 kg
[[Page 43184]]
(26,000 lbs.). Although the group of heavy vehicles that is not subject
to FMVSS No. 136 and the group of heavy vehicles that is subject to
FMVSS No. 136 are not solely defined by GVWR range, those not subject
to FMVSS No. 136 can be generally characterized as class 3-6 vehicles,
while those that are subject to FMVSS No. 136 can be generally
characterized as class 7-8 vehicles. Accordingly, NHTSA has further
examined rear-end crash data for each of these vehicle class ranges.
The lower weight range of class 3 through 6 includes vehicles such
as delivery vans, utility trucks, and smaller buses. Sales data for
2018 and 2019 show that on average 454,692 class 3-6 vehicles per year
were sold in the U.S.\25\ Approximately 57 percent of these were class
3 vehicles. Based on crash data, NHTSA determined that class 3-6
vehicles are involved in an annual average of 29,493 rear-end crashes
where the heavy vehicle is the striking vehicle. As a result of these
crashes, there were 184 fatalities, 14,675 injuries, and 41,285 PDOVs
per year on average. A NHTSA study also shows that, according to FARS
data, fatalities related to crashes involving these vehicles are on the
rise.\26\ In 2015, trucks and buses in this category were involved in 2
percent of all fatal crashes in the U.S., but that increased to 4
percent in 2019.\27\
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\25\ This information is available in the S&P Global's
presentation titled ``MHCV Safety Technology Study,'' which has been
placed in the docket identified in the heading of this NPRM.
\26\ Mynatt, M., Zhang, F., Brophy, J., Subramanian, R., Morgan,
T. (2022, September). Medium Truck Special Study (Report No. DOT HS
813 371). Washington, DC: National Highway Traffic Safety
Administration.
\27\ In 2015, 655 of the 32,538 total fatalities involved a
class 3-6 truck. In 2019, it increased to 1,301 of the 33,244 total
fatalities.
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The higher weight range of class 7 and 8 includes vehicles such as
larger single-unit trucks, combination tractor-trailers, transit buses,
and motorcoaches (GVWR greater than 11,793 kg (26,000 lbs.)).\28\ Sales
data for 2018 and 2019 shows that on average 332,558 class 7-8 vehicles
per year were sold in the U.S. Approximately 77 percent of these were
class 8 vehicles. NHTSA estimates that class 7 and 8 vehicles are
involved in 30,416 rear-end crashes where the heavy vehicle is the
striking vehicle. As a result of these crashes, there were an annual
average of 204 fatalities, 15,117 injuries, and 42,466 PDOVs. As these
data indicate, the numbers of crashes, fatalities, injuries, and PDOVs
are very similar for both class 3-6 and class 7-8.
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\28\ These vehicles are subject to FMVSS No. 136 and so must
have ESC.
---------------------------------------------------------------------------
Rear-End Crashes by Vehicle Travel Speed and Roadway Speed Limit
Pre-crash vehicle travel speed is highly important in understanding
the heavy vehicle rear-end crash problem and is perhaps the most
influential factor in outcome of these crashes. In NHTSA's analysis of
the data, travel speed of the striking vehicle was markedly different
when comparing non-fatal and fatal rear-end truck crashes. As shown in
Figure 1, the percentage of heavy vehicle rear-end crashes with a
fatality is greatest at higher travel speeds.\29\ Approximately 89
percent of fatal heavy vehicle rear-end crashes occur at above 80 km/h
(50 mph). For non-fatal heavy vehicle rear-end crashes, the trend is
more or less reversed, with approximately 83 percent of these crashes
occurring at travel speeds below 80 km/h (50 mph). These data
illustrate the distribution of a crash problem across all travel
speeds.
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\29\ Note that the figure shows percentage of the total number
of fatal or non-fatal crashes. The total number of crashes is much
greater for non-fatal crashes.
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BILLING CODE 4910-59-P
[[Page 43185]]
[GRAPHIC] [TIFF OMITTED] TP06JY23.001
The speed limits in heavy vehicle rear-end crashes also show a
similar trend. NHTSA categorized the fatal and non-fatal crash data
according to posted speed limit at the crash location, as illustrated
in Figure 2.\31\ These data show that over 90 percent of heavy vehicle
rear-end crashes with a fatality occur on roadways with a posted speed
limit higher than 50 mph (80 km/h). This reinforces the association
between higher speeds and fatal crash outcome in these types of
crashes. In contrast, non-fatal rear-end crashes tend to occur most
commonly on roads with lower speed limit, with a peak frequency at
speed limits of 45 mph (72 km/h). These data help in understanding the
conditions under which heavy vehicle rear-end crashes of different
severities occur.
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\30\ Data are from 2017-2019 FARS and CRSS crash databases, as
discussed in the PRIA section on target population.
\31\ These data naturally are clustered around 5 mph intervals
normally assigned for posted speed limits on roadways.
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[[Page 43186]]
[GRAPHIC] [TIFF OMITTED] TP06JY23.002
BILLING CODE 4910-59-C
Safety Problem That Can Be Addressed by AEB
NHTSA identified the set of crashes that might be prevented by AEB
systems equipped on heavy vehicles. To determine these crashes for this
NPRM, NHTSA analyzed 2017 through 2019 crash data for heavy vehicles.
The 2017 through 2019 years were chosen because they provide the most
recent available data, and thus reflect newer model year vehicles,
safety technologies, and crash environments.\33\ The crash-related
statistics discussed in this section, often depicted as annual
averages, are derived from these data.
---------------------------------------------------------------------------
\32\ Data are from 2017-2019 FARS and CRSS crash databases, as
discussed in the PRIA section on target population.
\33\ Crash data from 2020, although available, were excluded due
to a significant reduction in weighted cases for CRSS. The 2020 data
was greatly influenced by COVID-19 and might not reflect the long-
term trend of crash outcomes, as described in the accompanying PRIA.
---------------------------------------------------------------------------
To develop a target crash population relevant to AEB, the agency
identified crashes that were classified as rear-end crashes as
instructed by the FARS/CRSS manual and in which the striking vehicle
was a heavy vehicle. NHTSA analyzed rear-end crashes in which the
vehicle ahead is categorized as being either stopped, travelling at a
lower speed, or decelerating, and also examined a few other categories
to account for rear-end crashes that did not fit into the three
categories. Additionally, NHTSA included some other cases which,
although not classified as rear-end, were multi-vehicle crashes that
still involved the front end of a heavy vehicle colliding with the
rear-end of another vehicle.
NHTSA believes that AEB will help reduce the severity of rear-end
crashes occurring in a wide variety of real-world situations. However,
the data analysis presented some rear-end crash cases where, due to a
significant sequence of events or other conditions preceding the crash,
the agency had less certainty of the extent to which AEB systems would
be able to reduce the crash severity. For example, if the data
indicated that the heavy vehicle had changed lanes just prior to
colliding with a vehicle ahead, there would potentially not have been
sufficient time and/or space for the AEB system to properly identify
and track that vehicle and brake in time to avoid the crash. As another
example, if the road surface conditions were icy and slippery, the AEB
system may have been less likely to prevent a crash due to the reduced
friction and increased stopping distances. In another example, if the
struck vehicle was a motorcycle, NHTSA is uncertain of the AEB system's
capacity to perform optimally since motorcycles may be more difficult
to detect.\34\
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\34\ NHTSA is currently conducting research tests to understand
AEB performance in light vehicle rear-end crashes with motorcycles.
Two types of AEB sensor types (e.g., camera and camera+radar) were
investigated. See <a href="http://www.regulations.gov">www.regulations.gov</a>, Docket No. NHTSA-2022-0091. A
study by the RDW, the vehicle authority in the Netherlands,
indicated that adaptive cruise control systems (which detect a
vehicle ahead, similar to AEB) had more difficulty detecting
motorcycles. <a href="https://www.femamotorcycling.eu/wp-content/uploads/Final%20Report_motorcycle_ADAS_RDW.pdf">https://www.femamotorcycling.eu/wp-content/uploads/Final%20Report_motorcycle_ADAS_RDW.pdf</a> (last accessed February 10,
2023).
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NHTSA believes that, even in these situations where AEB performance
may be partially degraded, having AEB will still be beneficial. It may
not, for example, prevent a crash but it may reduce its severity by
slowing the
[[Page 43187]]
striking vehicle down. However, the agency took a conservative approach
and excluded cases such as those above from the target crash
population, and included only those cases in which AEB systems would
have the opportunity to perform optimally. This approach gives greater
confidence that the crashes included in the target crash population
would be prevented by having AEB-equipped vehicles.\35\
---------------------------------------------------------------------------
\35\ The PRIA discusses the rear-end crashes that were excluded
from the target population.
---------------------------------------------------------------------------
The result is that out of the 550,000 annual police reported
crashes involving heavy vehicles, approximately 60,000 annually are
rear-end crashes in which the heavy vehicle was the striking vehicle.
Thus, if heavy vehicles were equipped with AEB, a portion of these
60,000 crashes could be prevented. These 60,000 crashes, between 2017
and 2019, resulted in an annual average of approximately 388
fatalities, 30,000 injuries, and 84,000 PDOVs.
By requiring ESC for most class 3 through 6 vehicles, the proposed
rule would affect approximately 17,000 rollover and loss of control
crashes. These crashes resulted in 178 fatalities, 4,000 injuries, and
13,000 PDOVs, a portion of which could be prevented if class 3 through
6 heavy vehicles were equipped with ESC. These numbers are set forth in
Table 7.
Table 7--Target Crash Population
----------------------------------------------------------------------------------------------------------------
Crashes Fatalities Injuries PDOVs
----------------------------------------------------------------------------------------------------------------
AEB............................................. 60,000 388 30,000 84,000
ESC............................................. 17,000 178 4,000 13,000
----------------------------------------------------------------------------------------------------------------
III. Efforts To Promote AEB Deployment in Heavy Vehicles
Unlike with light vehicles in the U.S., there is currently no
voluntary commitment by heavy vehicle manufacturers to begin installing
AEB on all new vehicles.\36\ Nor is there a program similar to NHTSA's
New Car Assessment Program (NCAP) for heavy vehicles. However, NHTSA
and FMCSA have researched heavy vehicle AEB. In addition, Congress,
other governmental agencies, and a variety of stakeholders recognize
that this technology has the potential to reduce the fatalities,
injuries, and property damage associated with heavy vehicle rear-end
crashes. The installation rate of AEB in the U.S. vehicle fleet has
gradually increased, and the latest generations of the technology are
higher performing than the original implementations.
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\36\ On March 17, 2016, NHTSA and the Insurance Institute for
Highway Safety (IIHS) announced a commitment by 20 automakers
representing more than 99 percent of the U.S. auto market to make
lower speed AEB a standard feature on virtually all new cars no
later than Sept 1, 2022. <a href="https://www.nhtsa.gov/press-releases/us-dot-and-iihs-announce-historic-commitment-20-automakers-make-automatic-emergency">https://www.nhtsa.gov/press-releases/us-dot-and-iihs-announce-historic-commitment-20-automakers-make-automatic-emergency</a>.
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A. NHTSA's Foundational AEB Research
NHTSA has been studying emergency braking technologies since
manufacturers first introduced these technologies over fifteen years
ago. NHTSA has recognized the safety potential of heavy vehicle AEB for
many years and continued to research this technology as it evolved from
early generations to its current state. As part of NHTSA's efforts to
better understand these new crash avoidance technologies, NHTSA
sponsored and conducted numerous research projects focused on AEB and
FCW for heavy trucks. NHTSA conducted testing at its in-house testing
facility, the Vehicle Research and Test Center, to examine the
performance of AEB in different combinations of crash scenarios and
speeds.
NHTSA's foundational knowledge of braking technology was built on a
long history of work on FMVSS No. 105, ``Hydraulic and electric brake
systems,'' No. 121, ``Air brake systems,'' and No. 136, ``Electronic
stability control systems for heavy vehicles.''
FMVSS No. 105 applies to multipurpose passenger vehicles, trucks,
and buses with a GVWR greater than 3,500 kg (7,716 lbs.) that are
equipped with hydraulic or electric brake systems. This standard sets
performance requirements for, among other things, maximum stopping
distance, anti-lock braking systems, stability and control under
braking (including a curved and wet road surface), and recovery from
brake fade.\37\
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\37\ Brake fade events are associated with speed control on
roads with steep or gradual but long downgrades. As brake
temperature increases in a drum, its diameter expands as the metal
heats up; this means the brake shoe displacement must also increase
to be effective. Eventually, the shoe reaches the displacement
limit, and then brake effectiveness drops off.
---------------------------------------------------------------------------
FMVSS No. 121 applies to trucks, buses, and trailers equipped with
air (pneumatic) brake systems, with a few exceptions for special
vehicle types. Although NHTSA sets no standards regarding the choice
between using hydraulic, electric, or air brakes, vehicles with a
larger size and load carrying capacity are more likely to have air
brakes. Thus, air brakes are typically installed on some class 6 and
most class 7-8 vehicles. Lower classes often use hydraulic brakes. A
few examples of the requirements in FMVSS No. 121 are maximum stopping
distance, having ABS, maintaining stability and control when braking to
a stop on a curved and wet roadway test surface, recovering from brake
fade, and having an emergency (backup) brake system.
FMVSS No. 136 establishes performance and equipment requirements
for electronic stability control systems on truck tractors and certain
large buses, for the purpose of reducing crashes caused by rollover or
by loss of directional control. This standard currently applies to
truck tractors and certain large buses with a GVWR greater than 11,793
kilograms (26,000 lbs.). FMVSS No. 136 requires vehicles to be equipped
with an ESC system, and to meet several minimum performance
requirements. For example, when driven on a specified J-shaped test
lane under a variety of specified conditions and parameters which
induce ESC activation, the wheels of the heavy vehicle must remain
within the lane.
B. NHTSA's 2015 Grant of a Petition for Rulemaking
In October 2015, NHTSA granted a petition for rulemaking from the
Truck Safety Coalition, the Center for Auto Safety, Advocates for
Highway and Auto Safety, and Road Safe America. This petition requested
``the commencement of a proceeding to establish a safety regulation to
require the use of [FCW and AEB] on all vehicles (trucks and buses)
with a gross vehicle weight rating (GVWR) of 10,000 pounds (lbs.) or
more.'' The petitioners maintained that AEB has important benefits and
is a technology that has been improving in performance, but that a
regulation is needed to optimize the benefits of the
[[Page 43188]]
technology and increase the frequency of installation in heavy
vehicles. The agency granted this petition on October 16, 2015, noting
that NHTSA's research and evaluation were ongoing, and initiated a
rulemaking proceeding with respect to vehicles with a GVWR greater than
4,536 kg (10,000 lbs.).\38\
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\38\ Grant of petition for rulemaking, 80 FR 62487 (October 16,
2015).
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C. Congressional Interest
1. MAP-21
In July 2012, the Moving Ahead for Progress in the 21st Century Act
was enacted. MAP-21 included Subtitle G, the ``Motorcoach Enhanced
Safety Act of 2012.'' \39\ Section 32705 of MAP-21 directed the
Secretary (NHTSA, by delegation) to research and test forward and
lateral crash warning systems for motorcoaches and decide whether a
corresponding safety standard would accord with section 30111 of the
Safety Act. Section 32703(b)(3) directed the Secretary to consider
requiring motorcoaches to be equipped with stability enhancing
technology, such as electronic stability control, to reduce the number
and frequency of rollover crashes, and prescribe a standard if it would
meet the requirements and considerations of sections 30111(a) and (b)
of the Safety Act.\40\ In response, NHTSA issued FMVSS No. 136,
requiring ESC for certain truck tractors and buses (including
motorcoaches) with a GVWR greater than 13,154 kg (26,000 lbs.).
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\39\ Public Law 112-141, Sec. 32705.
\40\ Section 32703(b) required a regulation not later than two
years after the date of enactment of the Act if DOT determined that
such standard met the requirements of the Safety Act.
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2. Bipartisan Infrastructure Law
In November 2021, the Bipartisan Infrastructure Law (BIL) was
signed into law. Section 23010 of BIL is dedicated to AEB. Section
23010(a) of BIL defines an AEB system as a system on a commercial motor
vehicle that, based on a predefined distance and closing rate with
respect to an obstacle in the path of the vehicle, alerts the driver of
an obstacle and, if necessary, applies the brakes automatically to
avoid or mitigate a collision with that obstacle.
Section 23010(b) requires the Secretary to prescribe an FMVSS to
require all commercial motor vehicles \41\ subject to FMVSS No. 136 (or
a successor regulation) to be equipped with an AEB system. The FMVSS is
also required to establish performance standards for AEB systems. BIL
directs the Secretary to prescribe the standard not later than two
years after the date of enactment of the Act.
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\41\ As defined in 49 U.S.C. 31101, ``commercial motor vehicle''
means a self-propelled or towed vehicle used on the highways in
commerce principally to transport passengers or cargo, if the
vehicle has a gross vehicle weight rating or gross vehicle weight of
at least 10,001 pounds, whichever is greater; is designed to
transport more than 10 passengers including the driver; or is used
in transporting material found by the Secretary of Transportation to
be hazardous and transported in a quantity requiring placarding
under regulations.
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Under Section 23010(b)(2), prior to prescribing the FMVSS, the
Secretary is required to conduct a review of AEB systems in use in
applicable commercial motor vehicles and address any identified
deficiencies in those systems in the rulemaking proceeding, if
practicable. In addition, the Secretary is required to consult with
representatives of commercial motor vehicle drivers to learn about
their experience with AEB (including malfunctions and/or unwarranted
activations).
This NPRM is issued to meet these provisions of the BIL. NHTSA
conducted a review of AEB systems in use in commercial motor vehicles
to identify limits in those systems. A memorandum summarizing this
review has been placed in the docket for this NPRM and has informed the
development of the proposal. NHTSA is also currently conducting
research to study drivers' experiences with collision mitigation
technologies, including AEB. Comments are requested on the feasibility
of mandating AEB for commercial motor vehicles with GVWR greater than
10,000 pounds which are not currently subject to FMVSS No. 136. This
NPRM requests comments from representatives of commercial motor vehicle
drivers, and drivers themselves, regarding the experience with the use
of AEB systems. This NPRM also includes a series of questions in
section VII.E on which NHTSA seeks comment to obtain information about
drivers' experiences with AEB (including malfunctions and/or
unwarranted activations).
Section 23010(c) of the BIL relates to the regulations of FMCSA,
which regulate the operation of commercial motor vehicles. BIL requires
an FMCSR ensuring that the AEB systems required by the FMVSS for new
commercial vehicles subject to FMVSS No. 136 be in use at any time
during which the vehicle is in operation. This NPRM proposes this
FMCSR.\42\
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\42\ FMCSA has also created an apprenticeship program for novice
drivers of commercial motor vehicles pursuant to the BIL. The
program requires novice drivers to operate vehicles that possess an
active braking collision mitigation system, such as AEB. 87 FR 2477,
January 14, 2022.
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Finally, section 23010(d) of BIL requires DOT to complete a study
on equipping a variety of commercial motor vehicles not currently
required to comply with FMVSS No. 136 with AEB. This study is to
include an assessment of the feasibility, benefits, and costs
associated with installing AEB on these vehicles. As discussed in
greater detail later, the analysis accompanying this NPRM fulfills this
requirement.
D. IIHS Effectiveness Study
In a 2020 report, the Insurance Institute for Highway Safety
studied the effectiveness of FCW and AEB technology on class 8 trucks
and concluded that safety will improve if more trucks have these
technologies installed.\43\ IIHS used data extracted from video camera
footage and crash rates of police-reportable crashes. While the study
sample did not contain a large number of severe crashes, FCW and AEB
were still associated with significant reductions in rear-end crashes
involving trucks. On average, between the time of collision and moment
of system intervention, the velocity of the striking vehicle was
reduced by greater than 50 percent. The study concluded that safety
would improve if more trucks had these technologies installed.\44\ The
IIHS study was limited to class 8 trucks and involved certain fleets
and drivers which may not necessarily be representative of the U.S.
fleet as a whole. Because of this limitation, NHTSA could not use the
findings to calculate the potential benefits of this proposal.
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\43\ Teoh, Eric R. (2020, September). Effectiveness of front
crash prevention systems in reducing large truck crash rates.
Arlington, VA: Insurance Institute for Highway Safety. Available at
https://www.iihs.org/topics/bibliography/ref/
2211#:~:text=Results%3A%20FCW%20was%20associated%20with,%25%20for%20r
ear%2Dend%20crashes. (last accessed August 30, 2022).
\44\ Id.
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E. DOT's National Roadway Safety Strategy (January 2022)
This NPRM takes a crucial step in implementing DOT's January 2022
National Roadway Safety Strategy to address the rising numbers of
transportation deaths occurring on this country's streets, roads, and
highways.\45\ At the core of this strategy is the Department-wide
adoption of the Safe System Approach, which focuses on five key
objectives: safer people, safer roads, safer vehicles, safer speeds,
and post-crash care. The Department will launch new programs,
coordinate and improve existing programs, and adopt a
[[Page 43189]]
foundational set of principles to guide this strategy.
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\45\ <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> (last accessed August
23, 2022).
---------------------------------------------------------------------------
The National Roadway Safety Strategy highlights new priority
actions that target our most significant and urgent problems and are,
therefore, expected to have the most substantial impact. One of the key
Departmental actions to enable safer vehicles is initiating a
rulemaking to require AEB on heavy trucks. This NPRM proposes a Federal
Motor Vehicle Safety Standard to require AEB on heavy trucks and other
heavy vehicles.
F. National Transportation Safety Board Recommendations
The National Transportation Safety Board (NTSB) included AEB for
commercial vehicles in its 2021-2023 Most Wanted List.\46\ Among other
things, NTSB stated that NHTSA should complete standards for AEB in
commercial vehicles and require this technology in all highway vehicles
and all new school buses.
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\46\ NTSB Most Wanted List, <a href="https://www.ntsb.gov/Advocacy/mwl/Pages/mwl-21-22/mwl-hs-04.aspx">https://www.ntsb.gov/Advocacy/mwl/Pages/mwl-21-22/mwl-hs-04.aspx</a> (last accessed August 23, 2022).
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In 2015, NTSB issued a special investigation report,\47\ which
summarized previous, as well as new, findings related to AEB in a
variety of vehicles. Regarding heavy vehicles, this report presented
the following recommendation to NHTSA:
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\47\ National Transportation Safety Board. 2015. The Use of
Forward Collision Avoidance Systems to Prevent and Mitigate Rear-End
Crashes. Special Investigation Report NTSB/SIR-15-01. Washington,
DC. Available at <a href="https://www.ntsb.gov/safety/safety-studies/Documents/SIR1501.pdf">https://www.ntsb.gov/safety/safety-studies/Documents/SIR1501.pdf</a> (last accessed August 22, 2022).
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<bullet> H-15-05: Complete, as soon as possible, the development
and application of performance standards and protocols for the
assessment of forward collision avoidance systems in commercial
vehicles.
In a 2018 special investigation report,\48\ the NTSB discussed two
severe accidents involving school buses. In the conclusion of the
report, the NTSB stated that AEB could have helped mitigate the
severity of one of the accidents, and that ESC could have helped
mitigate the other. Accordingly, the following safety recommendations
were made or restated to NHTSA:
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\48\ National Transportation Safety Board. 2018. Selective
Issues in School Bus Transportation Safety: Crashes in Baltimore,
Maryland, and Chattanooga, Tennessee. NTSB/SIR-18/02 PB2018-100932.
Washington, DC. Available at <a href="https://www.ntsb.gov/investigations/AccidentReports/Reports/SIR1802.pdf">https://www.ntsb.gov/investigations/AccidentReports/Reports/SIR1802.pdf</a> (last accessed August 22, 2022).
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<bullet> H-18-08: Require all new school buses to be equipped with
collision avoidance systems and automatic emergency braking
technologies.
<bullet> H-11-7: Develop stability control system performance
standards for all commercial motor vehicles and buses with a gross
vehicle weight rating greater than 10,000 pounds, regardless of whether
the vehicles are equipped with a hydraulic or a pneumatic brake system.
<bullet> H-11-8: Once the performance standards from Safety
Recommendation H-11-7 have been developed, require the installation of
stability control systems on all newly manufactured commercial vehicles
with a gross vehicle weight rating greater than 10,000 pounds.
G. FMCSA Initiatives
FMCSA has been engaged in activities to advance the voluntary
adoption of AEB for heavy vehicles, primarily through the Tech-Celerate
Now (TCN) program. This program focuses on accelerating the adoption of
Advanced Driver Assistance Systems (ADAS), such as AEB, by the trucking
industry to reduce fatalities and prevent injuries and crashes, in
addition to realizing substantial return-on-investment through reducing
costs associated with such crashes for the motor carrier. Initiated in
September 2019 and completed in February 2022, the first phase of this
program encompassed research into ADAS technology adoption barriers; a
national outreach, educational, and awareness campaign; and data
collection and analysis.
Outreach accomplishments included development of training materials
for fleets, drivers, and maintenance personnel related to AEB
technology and return-on-investment (ROI) guides; educational videos on
ADAS braking, steering, warning, and monitoring technologies; a web-
based TCN ADAS-specific ROI calculator; four articles on ADAS
technologies; and a program website to host the training materials.
As part of the national outreach campaign, the program was promoted
on social media including LinkedIn and Twitter, and FMCSA conducted
presentations and booth exhibitions at conferences, webinars, and
virtual meetings. Recent efforts have included discussion of a safety
effective analysis project that is using two years of naturalistic data
collected from AEB and other ADAS technologies at the American Trucking
Associations Technology and Maintenance Council's 2022 Annual meeting,
the 2022 Midwest Commercial Vehicle Safety Summit, and the 2022
Southeast Commercial Vehicle Safety Summit. The results of this project
are expected be published late in calendar year 2023.
Planning is underway for the second phase of the TCN program, which
includes an expanded national outreach and education campaign,
additional research into the barriers to ADAS adoption by motor
carriers, and evaluation of the outreach campaign.
IV. NHTSA and FMCSA Research and Testing
A. NHTSA-Sponsored Research
The following are brief summaries of some of the research NHTSA
sponsored relating to strategies to avoid heavy vehicle collisions with
lead vehicles. The agency funded several research efforts to assess
collision avoidance systems, including AEB.
1. 2012 Study on Effectiveness of FCW and AEB
On August 2012, the University of Michigan Transportation Research
Institute (UMTRI) conducted a simulation study under a cooperative
agreement between NHTSA and AEB supplier WABCO.\49\ The objective of
the study was to estimate the safety benefits FCW and AEB systems
implemented on heavy trucks, including single-unit and tractor-
semitrailers. The study characterized technology, estimated a target
crash population, created a simulated reference crash database, and
assessed the impact of the technologies in a simulated environment.
These results were then applied to the target crash population. The
study not only simulated benefits for equipping heavy trucks with then-
available technology, but also simulated benefits for next and future
systems that were expected to have enhanced capabilities.
---------------------------------------------------------------------------
\49\ Woodrooffe, J., et al., ``Performance Characterization and
Safety Effectiveness Estimates of Forward Collision Avoidance and
Mitigation Systems for Medium/Heavy Commercial Vehicles,'' Report
No. UMTRI-2011-36, UMTRI (August 2012). Docket No. NHTSA-2013-0067-
0001, available at <a href="https://www.regulations.gov/document/NHTSA-2013-0067-0001">https://www.regulations.gov/document/NHTSA-2013-0067-0001</a>.
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The study simulated estimates based on next and future systems that
would utilize radar as the main sensor, and provided haptic, auditory,
and visual warnings to the driver (just as the current in-production
system). The in-production system could decelerate the vehicle up to a
maximum of 0.35g without any driver intervention. However, it could not
react to fixed objects (i.e., objects that were stationary before they
were in the range of the radar). The primary improvements expected for
the next system included the ability to react and brake at about 0.3g
in response to fixed objects and increased braking control authority on
stopped and moving vehicles to engage
[[Page 43190]]
the foundation brakes to produce as much as 0.6g of longitudinal
deceleration. The study used the same increased control authority on
stopped and moving vehicles as the next generation system, but required
the system to more aggressively react to fixed objects with
longitudinal deceleration of up to 0.6g.
Based on these capabilities, the study estimated that equipping all
tractor-semitrailers with AEB and FCW would reduce fatalities relative
to the base population for current, next, and future generation systems
by 24, 44, and 57 percent, respectively. Additionally, the predicted
reduction in injuries compared to the base population for current,
next, and future generation systems was estimated at 25, 47, and 54
percent, respectively. The combined annual benefit for straight truck
and tractor semitrailers, including property damage reduction for
current, next, and future generation systems was estimated at $1.4,
$2.6, and $3.1 billion, respectively.
The study concluded with multiple observations. The enhancements
depicted by the next generation system in comparison to the current
generation system were substantially larger than when comparing the
next generation to the future generation. These improvements were due
mainly to the ability of the system to react to fixed vehicles and the
increased braking. Overall, this evaluation depicted that the collision
mitigation measures studied would achieve significant benefits.
2. 2016 Field Study
NHTSA sponsored a field study with the Virginia Tech Transportation
Institute (VTTI) to assess the performance of heavy-vehicle crash
avoidance systems using 150 Class 8 tractor-trailers.\50\ The vehicles
were each equipped with a collision avoidance system from one of two
companies that included AEB and FCW. The purpose of the study was to
evaluate system reliability, assess driver performance over time,
assess overall driving behavior, provide data on real-world conflicts,
and generate inputs to a safety benefits simulation model.
---------------------------------------------------------------------------
\50\ See ``Field Study of Heavy-Vehicle Crash Avoidance
Systems'' (June 2016), available at <a href="https://www.nhtsa.gov/sites/nhtsa.gov/files/812280_fieldstudyheavy-vehiclecas.pdf">https://www.nhtsa.gov/sites/nhtsa.gov/files/812280_fieldstudyheavy-vehiclecas.pdf</a> (last accessed
June 3, 2022).
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The vehicles were operated by drivers for one year with a total of
over 3 million miles travelled. Each vehicle was equipped with a data
acquisition system that collected roadway-facing video, driver-facing
video, activations, and vehicle network data. About 85,000 hours of
driving and 885,000 activations were collected across all activation
types. Of the sampled 6,000 activations, 264 were AEB activations and
1,965 were impact alerts.
According to the study, safety benefits of collision avoidance
systems could be estimated based on data describing driver use of
systems and their responses to the activations. Since the systems
depict warnings through an audio and visual display, a precise model of
the benefits would show how fast drivers react and if reactions vary
based on warning type. For 84 percent of the AEB activations, the
driver reacted prior to the alert, and 13 percent of the time, the
driver responded to the alert. Drivers did not respond to 3 percent of
the AEB activations. Over 50 percent of the false AEB activations
received driver responses. Average driving speeds and headway distances
at the initiation of AEB activations prior to safety-critical events
were similar to values recorded for other activations. While at the
initiation of many warranted AEB activations, drivers had already
implemented braking, every warranted AEB activation did not receive a
driver reaction.
The analysis included a driver frustration assessment for each AEB
activation. This was a subjective assessment based on whether drivers
appeared to show frustration during an activation. Advisory warnings
resulted in lower percentages of general frustration. The highest
instances of frustration were noted during false activations with
frustration noted 11 percent of the time.
In summary, the study found that crash avoidance systems can be
effective in collision avoidance. Driver performance and behavior
exhibited almost no changes over time, and there was limited
frustration with the AEB activations. There were some limitations in
the study including varied calibration options between the systems, no
control group, different geographical locations, and unequal driving
time amongst participants.
3. 2017 Target Population Study
In 2017, NHTSA completed a study on a target population for AEB in
vehicles with a GVWR over 4,536 kg (10,000 pounds).\51\ The objective
of the study was to determine which forward collisions would
theoretically benefit from AEB if all vehicles over 4,536 kg (10,000
pounds) GVWR were equipped with the system. First, NHTSA reviewed
literature for then-existing AEB systems manufactured by Bendix and
Meritor. Although the systems varied in some ways, they shared a tiered
functionality approach, including the sequential use of auditory and
visible warnings, automatic torque reduction, application of the engine
retarder, and finally automatic brake application as needed.\52\ The
research efforts concentrated on the FCW and CIB elements.
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\51\ See ``A Target Population for Automatic Emergency Braking
in Heavy Vehicles,'' available at <a href="https://crashstats.nhtsa.dot.gov/Api/Public/Publication/812390">https://crashstats.nhtsa.dot.gov/Api/Public/Publication/812390</a> (last accessed June 7, 2022).
\52\ See page 8 ``A Target Population for Automatic Emergency
Braking in Heavy Vehicles,'' available at <a href="https://crashstats.nhtsa.dot.gov/Api/Public/Publication/812390">https://crashstats.nhtsa.dot.gov/Api/Public/Publication/812390</a> (last
accessed June 7, 2022).
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Second, collisions were sampled from NHTSA and FMCSA's Large Truck
Crash Causation Study \53\ for an engineering review because this
database provides comprehensive information on heavy vehicle collisions
in the United States. The engineering review focused on 29 crashes from
the Large Truck Crash Causation Study that involved injuries and
fatalities to determine whether FCW and/or CIB would be effective in
preventing the crash. Effectivity was defined as both reviewing
engineers determining that there was a 50 percent chance or greater
that the crash would be prevented. The analysis determined that FCW and
CIB would both be effective in preventing 17 of the 29 crashes, much
more often than cases in which only either was effective or neither was
effective. Considering a summary of the weighted effectiveness, the
combination of FCW and CIB were effective in 50 percent of the cases.
While FCW alone was effective in 23 percent of cases, there was a
significant 21 percent of cases where neither FCW nor CIB was
effective.\54\
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\53\ See ``Large Truck Crash Causation Study,'' available at
<a href="https://www.fmcsa.dot.gov/safety/research-and-analysis/large-truck-crash-causation-study-analysis-brief">https://www.fmcsa.dot.gov/safety/research-and-analysis/large-truck-crash-causation-study-analysis-brief</a> (last accessed October 19,
2022).
\54\ Additionally, there was at least one case that consensus
was not reached regarding the effectiveness of CIB, and there was no
investigation of crashes of lower severity where only property
damage resulted.
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Third, the outcomes from the first two phases allowed for the
development of filters to identify the categories of collisions that
AEB would improve. These filters were then implemented to collisions in
NHTSA's crash databases to approximate how many collisions annually AEB
could have prevented. A combination of data from the FARS and the GES
was used for the calculations while ensuring that an overlap in fatal
crashes was removed to prevent duplicate tallies. Vehicle collision
information for the United States
[[Page 43191]]
involving injuries and fatalities for years 2010 to 2012 was utilized
from these databases.\55\ Both injury-related and fatal collisions
totaled 5,457,387, and this total was filtered to determine the target
population. The filtering exclusions were made cautiously in order to
yield a conservative benefit estimate. Crashes during which the subject
vehicle departed from its original travel lane and the lead vehicle
maintained the lane were not included. Similarly, collisions involving
the lead vehicle changing from the original lane and the subject
vehicle remaining in its lane were excluded. Additional exclusions
included collisions on icy and snowy roads, situations where the lead
vehicle turns from a perpendicular street in front of the subject
vehicle, cases involving acceleration maneuvers to avoid collision,
collisions where the lead vehicle was obscured by an object, collisions
into motorcycles, and cases where the subject vehicle was traveling on
a curved road toward an object such as a guardrail.
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\55\ LTCCS was not selected due to the age of the crash data,
for it is possible heavy vehicle collisions differ tremendously
since 2001. The UMTRI Trucks Involved in Fatal Accidents study
(<a href="https://deepblue.lib.umich.edu/bitstream/handle/2027.42/107389/48532_A56.pdf?isAllowed=y&sequence=1">https://deepblue.lib.umich.edu/bitstream/handle/2027.42/107389/48532_A56.pdf?isAllowed=y&sequence=1</a>, last accessed June 3, 2022)
was excluded because its detailed information regarding vehicle
style and driving time is only provided for collisions involving
fatalities, where data for collisions of less severity involving
only injuries would not be available.
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Fourth, the target population estimated in the third phase was
modified to reflect recent and probable future regulations. This
modification eliminated collisions that would be avoided based on the
implementation of other required technologies that had not yet
completely proliferated in heavy vehicles. Accounting for safety
equipment including ESC, ABS, and speed limiters allowed for the
overall target population to be modified to reflect the anticipated
number of future collisions. Crashes that were included in the final
future target population were those involving heavy vehicles in which
the rear-end crash resulted in injuries and fatalities. Further, the
crashes were refined to include only crashes where both vehicles
remained in the original lane after the crash was deemed imminent and
collisions where lane changes prior to crash imminency were allowed as
long as only one of the vehicles changed lanes. Additionally,
situations where the driver attempted to steer around the collision or
used insufficient braking were included.
After all adjustments were completed, the study estimated a target
population of 11,499 crashes annually involving 7,703 injured persons
and 173 fatalities. It also discussed possible sampling error as well
as three sources of uncertainty. However, the size of a target
population provided only an estimated upper bound to the benefits at
that time. The report added value in the detailed descriptions of
affected crashes and subpopulation breakouts that have traditionally
fed into benefits estimation.
4. 2018 Cost and Weight Analysis
In 2018, Ricardo Inc. completed a study sponsored by NHTSA that
focused on the cost and weight implications of requiring AEB on heavy
trucks. The study aimed to determine the product price, total system
cost, incremental consumer price, and weight of FCW and AEB systems on
heavy trucks to provide insight into the safety and efficiency benefits
of using the systems.\56\ The initial steps of the study were vehicle
research, vehicle segregation, and vehicle selection. Model year 2015-
2018 heavy vehicles manufactured by Ford, Cascadia, Volvo, Daimler, and
International LT were chosen for teardown examination and ranged in
mean annual sales from approximately 24,000 to 86,542. The associated
FCW and AEB systems installed on these vehicles were manufactured by
Delphi Technologies, Meritor, Bendix Commercial Vehicle Systems, and
Detroit Assurance (Daimler).
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\56\ Ricardo, Inc. (2018), ``Cost and Weight Analysis of Heavy
Vehicle Forward Collision Warning (FCW) and Automatic Emergency
Braking (AEB) Systems for Heavy Trucks'' Van Buren Township, MI.
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Service technician consultations, manuals, and OEM parts
descriptions were used to itemize components of the FCW and AEB
systems. Specific assessments of the related displays, sensors,
mounting hardware, and other elements of the FCW and AEB systems were
provided to prevent extraneous parts from being included in the cost
and weight evaluations. The cost and weight evaluations were executed
by a group of automotive system and integration experts, cost modeling
specialists, and procurement personnel. A bill of materials was
compiled using a ``teardown'' process to inventory the parts, define
manufacturing processes, and ascertain materials utilized. Specialized
cost software allowed for calculation of cost and weight.
In general, components that were not distinct to the FCW and AEB
systems were not included in the cost and weight evaluation. Therefore,
shared parts such as electronic control units and wiring harnesses were
not considered as additions if they were already incorporated into the
vehicle configuration without FCW/AEB. The manufacturing costs were
estimated, factoring in research and development, labor, material
costs, machinery, machine occupancy and tooling.
The five selected vehicles were the Ford F-Series Super Duty,
Freightliner M2-106, Freightliner Cascadia, International LT, and Volvo
VNL. While there was some overlap of similar components, the FCW and
AEB systems in the five selected vehicles had substantial variation
amongst the system mechanisms and functionality. Based on these
differences the vehicles were separated into four groups, and the
average manufacturing costs and weights were assessed for each
category. Overall, the average incremental cost to manufacturers for
these FCW/AEB systems ranged from $44.23 to $197.51; and associated
end-user prices ranged from $70.80 to $316.18. Additionally, the
average incremental weights ranged from approximately 0.46 to 3.10 kg.
B. VRTC Research Report Summaries and Test Track Data
1. Relevance of Research Efforts on AEB for Light Vehicles
AEB was first introduced on light vehicles. For this reason,
NHTSA's research and testing of AEB systems began with light vehicles
and was subsequently used to inform NHTSA's work on heavy vehicle AEB.
NHTSA conducted extensive research on AEB systems to support
development of the technology and eventual deployment in vehicles.
There were three main components to this work. Early research was
conducted on FCW systems that warn drivers of potential rear-end
crashes with other vehicles. This was followed by research into AEB
systems designed to prevent or mitigate rear-end collisions through
automatic braking.
NHTSA's earliest research on FCW systems began in the 1990s, at a
time when the systems were under development and evaluation had been
conducted primarily by suppliers and vehicle manufacturers. NHTSA
collaborated with industry stakeholders to identify the specific crash
types that an FCW system could be designed to address, the resulting
minimum functional requirements, and potential objective test
procedures for evaluation.\57\ In the late 1990s, NHTSA
[[Page 43192]]
worked with industry to conduct a field study, the Automotive Collision
Avoidance System Program. NHTSA later contracted with the Volpe
National Transportation Systems Center (Volpe) to conduct data analyses
of data recorded during that field study.\58\ From this work, NHTSA
learned about the detection and alert timing and information about
warning signal modality (auditory, visual, etc.) of FCW systems, and
predominant vehicle crash avoidance scenarios where FCW systems could
most effectively play a role in alerting a driver to brake and avoid a
crash. In 2009, NHTSA synthesized this research in the development and
conduct of controlled track test assessments on three vehicles equipped
with FCW.\59\
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\57\ This research was documented in a report, ``Development and
Validation of Functional Definitions and Evaluation Procedures for
Collision Warning/Avoidance Systems,'' Kiefer, R., et al., DOT HS
808 964, August 1999. Additional NHTSA FCW research is described in
Zador, P.L., et al., ``Final Report--Automotive Collision Avoidance
System (ACAS) Program,'' DOT HS 809 080, August 2000; and Ference,
J.J., et al., ``Objective Test Scenarios for Integrated Vehicle-
Based Safety Systems,'' Paper No. 07-0183, Proceedings of the 20th
International Conference for the Enhanced Safety of Vehicles, 2007.
\58\ Najm, W.G., Stearns, M.D., Howarth, H., Koopmann, J., and
Hitz, J., ``Evaluation of an Automotive Rear-End Collision Avoidance
System,'' DOT HS 810 569, April 2006 and Najm, W.G., Stearns, M.D.,
and Yanagisawa, M., ``Pre-Crash Scenario Typology for Crash
Avoidance Research,'' DOT HS 810 767, April 2007.
\59\ Forkenbrock, G., O'Harra, B., ``A Forward Collision Warning
(FCW) Program Evaluation, Paper No. 09-0561, Proceedings of the 21st
International Technical Conference for the Enhanced Safety of
Vehicles, 2009.
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NHTSA's research and test track performance evaluations of AEB
began around 2010. The agency began a thorough examination of the state
of forward-looking advanced braking technologies, analyzing their
performance and identifying areas of concern or uncertainty, to better
understand their safety potential. NHTSA issued a report \60\ and a
request for comments (RFC) seeking feedback on its CIB and DBS research
in July 2012.\61\ Specifically, NHTSA wanted to enhance its knowledge
further and help guide its continued efforts pertaining to AEB
effectiveness, test operation (including how to ensure repeatability
using a target or surrogate vehicle), refinement of performance
criteria, and exploration of the need for ``false positive'' tests to
minimize the unintended negative consequences of automatic braking in
non-critical driving situations where a crash was not imminent.
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\60\ The agency's initial research and analysis of CIB and DBS
systems were documented in a report, ``Forward-Looking Advanced
Braking Technologies: An analysis of current system performance,
effectiveness, and test protocols'' (June 2012). <a href="http://www.regulations.gov">http://www.regulations.gov</a>, NHTSA 2012-0057-0001.
\61\ 77 FR 39561.
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NHTSA considered feedback it received on the RFC and conducted
additional testing to support further development of the test
procedures. The agency's work was documented in two additional reports,
``Automatic Emergency Braking System Research Report'' (August 2014)
\62\ and ``NHTSA's 2014 Automatic Emergency Braking (AEB) Test Track
Evaluations'' (May 2015),\63\ and in accompanying draft CIB and DBS
test procedures.\64\
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\62\ <a href="https://www.regulations.gov">https://www.regulations.gov</a>, NHTSA 2012-0057-0037.
\63\ DOT HS 812 166.
\64\ <a href="https://www.regulations.gov">https://www.regulations.gov</a>, NHTSA 2012-0057-0038.
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In 2016, NHTSA published a report identifying the most recurrent
AEB-relevant pre-crash scenarios for heavy vehicles. NHTSA identified
the three most recurrent situations as a heavy vehicle moving toward a
stopped lead vehicle, a heavy vehicle moving toward a slower moving
lead vehicle, and a heavy vehicle moving toward a lead vehicle that is
decelerating.\65\ These were the same three crash scenarios that had
been identified as the most prevalent AEB-relevant crash scenarios for
light vehicles.
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\65\ Boday, C., et al., ``Class 8 Truck-Tractor and Motorcoach
Forward Collision Warning and Automatic Emergency Braking Test Track
Research--Phase I,'' Washington, DC: National Highway Traffic Safety
Administration (June 2016). Docket No. NHTSA[hyphen]2015-0024-0004.
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2. Phase I Testing of Class 8 Truck-Tractors and Motorcoach
In 2016, NHTSA published its first report on track-testing of AEB
for heavy vehicles. The previous studies describing the test procedures
for light vehicles provided a framework for the establishment of heavy
vehicle test procedures. Since test procedures were not yet developed
for heavy vehicles, the goal of the research was to first adapt
existing testing protocols for light vehicle AEB and then follow these
adapted test procedures to quantify the performance of FCW and AEB
systems on heavy vehicles. The research was conducted in two phases.
NHTSA's Phase I work began with using a combination of the specific
test situations established for NHTSA's NCAP for assessment of FCW and
AEB systems and a modified version of the light vehicle test procedures
to create heavy vehicle draft research test procedures. NCAP tests
involved use of a strikable surrogate vehicle; however, for early heavy
vehicle Phase I work, NHTSA used a surrogate lead vehicle comprised of
canvas-covered foam to exhibit geometric and reflective features of the
rear of a passenger car. The testing for Phase I was performed with
four heavy vehicles outfitted with FCW and AEB, including three Class 8
truck-tractors and one Class 8 motorcoach. Specifically, the four Class
8 vehicles were a 2006 Volvo VNL 64T630 6x4 tractor, a 2006
Freightliner Century Class 6x4 tractor, a 2012 Freightliner Cascadia
6x4 tractor, and a 2007 MCI 56-passenger motorcoach (bus). Each vehicle
was equipped with ABS, ESC, FCW, and AEB systems. The 2006 and 2012
Freightliners and the MCI motorcoach employed a Meritor WABCO system,
and the 2006 Volvo was equipped with a Bendix Wingman Advanced system.
In general, the FCW and AEB systems utilized a front bumper mounted
sensor to detect objects in front of the vehicle and a display to warn
the driver with audio and visual alerts.
For each vehicle, NHTSA planned to run ten tests that are
summarized in Table 8. These situations covered the three most common
AEB-relevant pre-crash scenarios, as well as two false positive tests
and two tests performed at different weighted conditions.
Table 8--Phase I Test Scenarios
----------------------------------------------------------------------------------------------------------------
Lead vehicle Subject vehicle Lightly loaded Loaded at GVWR
Scenario speed (km/h) speed (km/h) (number of trials) (number of trials)
----------------------------------------------------------------------------------------------------------------
Lead vehicle Stopped................. 0 40 10 ..................
Lead Vehicle Moving.................. 16 40 10 10
Lead Vehicle Moving.................. 32 72 10 10
Lead Vehicle Decelerating............ 40 40 10 10
Lead Vehicle Decelerating............ 48 48 .................. 10
Lead Vehicle Decelerating............ 56 56 5 5
Steel Trench Plate False Positive.... N/A 40 5 5
[[Page 43193]]
Steel Trench Plate False Positive.... N/A 72 5 5
----------------------------------------------------------------------------------------------------------------
The test scenarios were defined by the initial speeds of the
subject vehicle and lead vehicle, and the starting headway distance
between the vehicle was monitored. For all the tested scenarios, the
test driver was instructed to modulate the accelerator pedal to
maintain the desired test speed until FCW initiated, upon which the
accelerator pedal input was removed. Steering was applied to maintain
lateral position test tolerances to the lead vehicle. Manual brake
pedal applications were only applied in certain scenarios where AEB was
not designed to activate, or an impact occurred with the leading
surrogate vehicle. Additionally, the previously described test
situations were conducted under both a lightly loaded condition and a
fully loaded vehicle weight condition (i.e., loaded up to the vehicle's
GVWR). Based upon potential damage to the subject vehicle, the
feasibility of completing each test scenario with the specific load,
and the fact that there was no discernable difference between the
performance under the lightly loaded and GVWR loaded conditions in the
trials executed, some of the speed combinations were not investigated
under both loads. The false positive tests were conducted by driving
the selected vehicles toward and over a steel trench plate to determine
if these commonly used road construction covers would trigger false
alerts or unintentional automatic braking.
Stationary lead vehicle testing was limited to the 2006 Volvo, as
it was equipped with the only system that would trigger an FCW on
stationary vehicles. At the time these evaluations were performed, none
of the systems tested were designed to activate AEB on stationary
vehicles. During every slower moving lead vehicle test, FCW was
activated. Additionally, every vehicle's AEB activated and avoided
collision during each slower moving test performed with a subject
vehicle speed of 40 km/h, and a lead vehicle speed of 16 km/h.
The lead vehicle decelerating test was used to evaluate all four
heavy vehicles, but multiple test adjustments had to be applied. For
the lead vehicle decelerating test performed with both the subject and
lead vehicle speeds of 40 km/h, the lead vehicle was slowed to 8 km/h
instead of a stop to account for the failure of the subject vehicles to
activate AEB for stopped vehicles. Once the change was implemented,
both the FCW and the AEB systems were activated, and speeds were
reduced. Collisions between the subject and lead vehicle did occur, but
testing of this scenario mainly led to the observation that the test
procedure's headway would also have to be adjusted since heavy vehicles
have different braking capabilities than light vehicles.
The steel trench plate false positive test was performed using the
2006 Volvo, 2006 Freightliner, and 2007 MCI at 40 km/h and 72 km/h.\66\
For both velocities examined, the 2006 Freightliner and 2007 MCI
exhibited no false positives in all five trials. However, the 2006
Volvo triggered unnecessary auditory warnings in all five trials for
both velocities. None of the false positive testing trials resulted in
AEB system activation.
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\66\ The 2012 Freightliner was not evaluated with steel trench
plate scenario due to the short window that the vehicle was
available for testing.
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During this early testing, the surrogate lead vehicle was towed
onto the test track and fixed laterally in the test lane via a low-
profile plastic monorail track. Initially, the test system employed a
low-stretch rope to pull the surrogate lead vehicle by a tow vehicle.
This configuration performed well in the slower moving lead vehicle
situation because the lead vehicle moves at a constant velocity,
allowing the tow rope to stay in tension. In contrast, when testing the
lead vehicle decelerating scenario, the tension in the tow rope was not
maintained once the tow vehicle decelerated, and subsequently the tow
rope was prone to becoming stuck under the surrogate lead vehicle. This
issue resulted in a loss of surrogate lead vehicle lateral stability
and consequently decreased the test repeatability.
To address this shortcoming, the foam surrogate lead vehicle was
replaced with a vertical cylinder wrapped with a layer of radar
reflective material secured to the top of a movable platform with more
consistent and stable deceleration properties. However, because the
cylinder was not representative of a real vehicle, this was identified
as needing further development and modification of the test protocols.
A significant portion of this early AEB testing focused on
developing draft research test procedures that could be used to safely
and objectively assess AEB performance. The development history of test
protocols is important for two reasons. First, it explains how NHTSA
came to the conclusion to propose the performance parameters described
in the notice and its basis that the performance requirements are
objective and practicable. Second, it provides some context as to some
of the limitations of early performance evaluations of AEB for heavy
vehicles. In general, this initial phase of research demonstrated that
the scenarios were generally repeatable and practical, and the tests
showed additional development would potentially result in better
controlled deceleration and stability of the lead vehicle.
3. Phase II Testing of Class 8 Truck-Tractors
NHTSA's primary objectives of the Phase II efforts were to continue
to develop the FCW and AEB test procedures executed in Phase I such
that they could be effectively utilized on a closed-course track test
to assess performance of heavy vehicle FCW and AEB systems. For this
testing, NHTSA used four Class 8, truck-tractors, three of which were
from Phase I. The fourth vehicle from Phase I, the MCI motorcoach, was
replaced with a 2016 Freightliner. Specifically, these subject vehicles
were a 2016 Freightliner, a 2012 Freightliner, a 2006 Volvo, and a 2006
Freightliner. Like in Phase I, all vehicles were outfitted with ABS,
ESC, FCW, and AEB systems. Both the 2006 and 2012 Freightliners
employed the Meritor WABCO system, the 2016 Freightliner had the
Detroit Assurance Safety System, and the 2006 Volvo utilized the Bendix
Wingman Advance system. All AEB systems on the selected vehicles
utilized radar installed on the front bumper and each AEB system
provided auditory and visual alerts. For Phase II testing, NHTSA used
the test scenarios from Phase I; however, a second false positive test
scenario was added. Specifically, NHTSA investigated a pass-through
test from
[[Page 43194]]
Europe's AEB requirements \67\ involving a subject vehicle being driven
in a central lane between two parked vehicles.
---------------------------------------------------------------------------
\67\ United Nations, ``Uniform provisions concerning the
approval of motor vehicles with regard to the Advanced Emergency
Braking Systems (AEBS)'' 2013. Available at <a href="https://unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2013/R131e.pdf">https://unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2013/R131e.pdf</a> (last accessed
February 10, 2023).
---------------------------------------------------------------------------
While other standards \68\ were considered for this research study,
the use of United States collision data and different testing goals led
to establishment of specific test procedures. While vehicle test speeds
were similar, with some overlap, NHTSA's test procedures included
higher velocity tests to be executed at 55 km/h with more
specifications governing the test conditions and test completion.
NHTSA's Phase II test scenario matrix is summarized in Table 9.
---------------------------------------------------------------------------
\68\ The following were among the standards considered:
International Organization for Standardization (ISO) 22839:2013,
``Intelligent transport systems--Forward vehicle collision
mitigation systems--Operation, performance, and verification
requirements; ISO 15623:2013, ``Intelligent transport systems--
Forward vehicle collision warning systems--Performance requirements
and test procedures,'' and SAE International recommended practice
J3029, ``Forward collision warning and mitigation vehicle test
procedure--Truck and bus.''
---------------------------------------------------------------------------
Phase II also further enhanced the testing of Phase I by
implementing a new strikable surrogate vehicle (SSV) system as the lead
vehicle. The SSV system was created for NHTSA's light vehicle AEB
assessment and was engineered to enhance test repeatability and lateral
stability in higher velocity tests.
Table 9--Phase II Test Scenarios
----------------------------------------------------------------------------------------------------------------
Lead vehicle Subject vehicle Lightly loaded Loaded at GVWR
Scenario speed (km/h) speed (km/h) (number of trials) (number of trials)
----------------------------------------------------------------------------------------------------------------
Lead Vehicle Stopped................. 0 40 6 8
Lead Vehicle Moving.................. 0 40 8 8
Lead Vehicle Moving.................. 35 75 8 8
Lead Vehicle Decelerating............ 40 40 8 8
Lead Vehicle Decelerating............ 55 55 6 or 8 6 or 8
Steel Trench Plate False Positive.... N/A 40 8 8
Steel Trench Plate False Positive.... N/A 75 8 8
Stationary Vehicle False Positive.... N/A 50 8 8
----------------------------------------------------------------------------------------------------------------
The SSV served as the lead vehicle or the vehicle test device (VTD)
in the AEB tests. The rear of the SSV was designed to depict features
of a typical passenger car. The carbon fiber surrogate exemplified
these aspects, considering physical measurements, reflective
properties, and visual characteristics. Its structure was not only
developed to be detected as a real vehicle by the AEB systems, but it
was also intended to endure wind gusts and recurrent impacts up to
approximately 40 km/h. The required surrogate test velocities and
deceleration of the VTD were achieved by a tow vehicle equipped with a
brake controller in conjunction with a towed two-rail track used to
move the SSV during the test.
NHTSA implemented changes in the test procedures from Phase I to
Phase II. The Phase II test procedures contained more detail as input
from within NHTSA and data collected during both phases of heavy
vehicle research were used to develop and refine the procedures. For
example, the test procedures contained structure for test scenario
descriptions, minimum data channels to collect, and general testing
requirements (e.g., ambient temperature range, wind, speed, brake
burnish, etc.). Definitions were added for when the initial test
conditions started, and more detail was added to the definition of when
a test trial ended. The test conditions were established to be on dry,
straight roadways in the daylight, based on a previous analysis of
crash data and observed safety critical events in field operation
testing. FCW activation, AEB activation, collision detection, and
accelerator pedal release time were measured in the tests. Similar to
Phase I, the testing of each scenario occurred under two different load
conditions.
After reviewing the Phase I test outcomes, NHTSA determined that
the lead vehicle stopped scenario could only be assessed by the latest
model year test vehicle outfitted with a capable AEB system. In Phase
II, the subject vehicle traveled 40 km/h and approached a stationary
lead vehicle in the same lane. Valid trials required the driver to
remain centered in the traveling lane and continue driving at the
target velocity until AEB was triggered. Once AEB was triggered, the
test driver fully released the accelerator pedal, and the driver was
not allowed to use the brake pedal of the test vehicle unless the
vehicle collided with the lead vehicle or if the AEB system completely
stopped the vehicle. The results showed that FCW was activated,
followed by automatic braking by the AEB system in all 8 trials
performed under the GVWR condition.
The lead vehicle moving test situation was evaluated at multiple
velocity combinations for all four test vehicles. During this test, the
subject test vehicle traveled at 40 km/h or 75 km/h and approached a
slower-moving lead vehicle traveling at 15 km/h or 35 km/h,
respectively, in the same lane. Valid trials required the driver to
remain centered in the traveling lane and continue driving at the
target velocity until AEB was triggered. Once AEB was triggered, the
test driver fully released the accelerator pedal. Testing for this
scenario was conducted for both lightly loaded and GVWR conditions. All
of the vehicles tested consistently issued FCW alerts and activated the
AEB systems; however, impacts occurred.
The lead vehicle decelerating situation was executed with all the
test vehicles except the 2006 Volvo due to its Phase I performance. Two
initial velocity and initial headway combinations of the subject and
lead vehicles were tested (i.e., 40 km/h and 80 m; 55 km/h and 23 m).
After a short period of steady state driving using constant speeds and
a constant headway, the lead vehicle was braked at approximately 0.3g
while traveling in the same lane as the subject vehicle. The subject
vehicle driver kept the subject vehicle centered in the traveling lane
and continued driving until AEB was triggered. Under both the lightly
loaded and GVWR load conditions testing was completed.
The lead vehicle decelerating test scenario with initial test
speeds of 55 km/h and 23 m of headway presented the greatest challenges
when compared to other tests. In Phase II, the initial headway was
changed from 30.5 m to 23
[[Page 43195]]
m to keep the lead vehicle from transitioning to a stopped lead vehicle
test scenario near the end of a test trial, as it did in Phase I
testing with a headway of 30.5 m. Testing for this scenario was
conducted for both lightly loaded and GVWR conditions and all four
vehicles. All of the vehicles consistently issued FCW alerts and
activated the AEB systems; however, most tests resulted in impact.
Two false positive test types were also conducted. The steel trench
plate scenario was executed at 40 km/h and 75 km/h for all test
vehicles. Each vehicle was evaluated in the GVWR load condition, but
only the 2016 Freightliner was also assessed in the lightly loaded
condition. Most of the vehicles did not exhibit any FCW or AEB
activations in these tests. However, one vehicle's FCW/AEB system
perceived the steel trench plate as a stationary object on the path of
travel and the reaction to this false positive detection was not
consistent in terms of warning time, brake initiation time, and
deceleration level. The second test involved two stationary vehicles in
lanes on either side of the test vehicle's travel lane; and only the
2012 Freightliner and the 2016 Freightliner were evaluated under the
GVWR load condition. Neither vehicle exhibited any false FCW or AEB
activations in this test.
Overall, the Phase II test results demonstrated the ability of the
vehicles and AEB systems tested to avoid contact in the lead vehicle
stopped and lead vehicle moving test scenarios at the different
velocities and achieve no collisions. These capabilities extended to
the lead vehicle decelerating tests performed at 40 km/h and a headway
of 80 m. In contrast, there was a much lower likelihood of these
vehicles avoiding contact with the lead vehicle using an initial speed
of 55 km/h and a headway of 23 m.
4. NHTSA's 2018 Heavy Vehicle AEB Testing
NHTSA conducted test track research in 2017 and 2018 on heavy
vehicles equipped with FCW and AEB. This section describes the third
phase of NHTSA's heavy vehicle testing and the results from three
single-unit trucks. These trucks included a class 3 2016 Freightliner
3500 Sprinter, a class 6 2017 International 4300 SBA 4x2, and a class 7
2018 Freightliner M2-106. The main goal of this third phase was to
develop objective test procedures for evaluating the performance of
heavy vehicles equipped with FCW and AEB systems on a closed course
test track.
Table 10--Phase III Test Scenarios
----------------------------------------------------------------------------------------------------------------
Lead vehicle Subject vehicle Initial
Scenario speed (km/h) speed (km/h) headway (m)
----------------------------------------------------------------------------------------------------------------
Lead Vehicle Stopped............................................ 0 40 55
Lead Vehicle Moving............................................. 15 40 35
Lead Vehicle Moving............................................. 35 75 56
Lead Vehicle Decelerating....................................... 40 40 80
Lead Vehicle Decelerating....................................... 55 55 23
Steel Trench Plate False Positive............................... N/A 40 56
Steel Trench Plate False Positive............................... N/A 75 105
Stationary Vehicle Pass-Through False Positive.................. N/A 50 60
----------------------------------------------------------------------------------------------------------------
In this third phase of research, the newly developed heavy vehicle
AEB test procedures included test conditions where the driver applies
the subject vehicle brakes while approaching a lead vehicle, but with
an input insufficient to prevent a rear-end crash, to complement the
previously developed scenarios.
The 2017 International 4300 was outfitted with a Bendix system
which includes FCW and AEB. This system was enhanced since Phase II of
NHTSA's research where, in Phase III, it used camera and radar to
engage automatic emergency braking and demonstrated the ability to
respond to traveling and stationary vehicles. The FCW provided alerts
at velocities greater than 8 and 15 km/h for moving and stationary
objects, respectively. For the AEB system to be engaged, the vehicle
had to travel above 25 km/h.
The 2018 Freightliner M2-106 was outfitted with an OnGuardACTIVE
Collision Mitigation system which features FCW and AEB. This system
used radar to engage automatic emergency braking and displayed the
ability to respond to traveling and stationary vehicles. The FCW
provided alerts with visual and auditory cues and a braking warning was
issued when the AEB was activated. In order for the AEB system to be
engaged, the vehicle had to travel above 25 km/h.
The study concluded that the test procedures were reproducible and
appropriate for heavy vehicles outfitted with FCW and AEB systems.
After Phase II, the test procedures and scenarios were updated and
applied to heavy vehicles with different weight classifications. The
inclusion of heavy vehicles with updated AEB systems in Phase III
allowed for evaluation of more systems in the lead vehicle stopped
scenario; during the lead vehicle stopped evaluations with no driver
braking, at least one vehicle experienced no collisions for all trials
tested. This showed improvement in comparison to the prior phase, which
was only able to test lead vehicle stopped on one vehicle and resulted
in multiple collisions. The lead vehicle moving scenario test results
also displayed improvement where the percentage of collisions decreased
in comparison to Phase II. Overall, the outcomes showed that the FCW/
AEB systems have the capacity for being able to decrease rear-end
collisions by exhibiting velocity reductions before a collision or
avoiding contact with a lead vehicle entirely. While some FCW false
positives were observed, the overall results depicted that the systems
have the ability to avoid collision on the test track.
The results of this research show that the test procedures are
applicable to many heavy vehicles and indicate that performance
improvements in heavy vehicles equipped with these safety systems can
be objectively measured.\69\ Further, this was the first phase of the
series that was able to apply the test procedures to single-unit trucks
across multiple weight classifications; and new test scenarios were
added.
---------------------------------------------------------------------------
\69\ Salaani, M.K., Elsasser, D., Boday, C., ``NHTSA's 2018
Heavy Vehicle Automatic Emergency Braking Test Track Research
Results,'' SAE International. J Advances & Current Practices in
Mobility 2(3):1685-1704, 2020, doi:10.4271/2020-01-1001.
---------------------------------------------------------------------------
5. NHTSA's Research Test Track Procedures
NHTSA's most recently published heavy vehicle AEB research test
track
[[Page 43196]]
procedures were published in March 2019 and evaluate AEB performance in
crash-imminent scenarios both with and without manual brake pedal
applications.\70\ These procedures, with some modification, form the
basis for the proposed test procedure in this NPRM.
---------------------------------------------------------------------------
\70\ Elsasser, D., Salaani, M.K., & Boday, C., ``Test track
procedures for heavy-vehicle forward collision warning and automatic
emergency braking systems,'' Report No. DOT HS 812 675, Washington,
DC: National Highway Traffic Safety Administration (March 2019).
Available at <a href="https://rosap.ntl.bts.gov/view/dot/42186/dot_42186_DS1.pdf">https://rosap.ntl.bts.gov/view/dot/42186/dot_42186_DS1.pdf</a> (last accessed June 28, 2022).
---------------------------------------------------------------------------
The test procedures were based upon prior research and include the
lead vehicle stopped, lead vehicle moving, and lead vehicle
decelerating test scenarios, as well as the steel trench plate and
stationary vehicles false positive scenarios. The testing was divided
into three phases. First, the subject vehicle and the lead vehicle are
situated on the test track to the proper location and test velocity.
The second stage involves determining whether the vehicles have met the
proper starting test conditions to achieve valid and reproducible test
outcomes. The third and final stage serves to assess test validity and
system performance as well as response to any FCW or AEB triggers. In
the research test procedure, if an invalid test is detected, the test
is repeated until at least seven valid test attempts are completed.
Testing was executed during daylight, avoiding inclement weather and
irrelevant obstructions such as overhead signs, bridges, overpasses,
etc. For test procedures that include manual brake pedal applications,
the pedal was displaced at a rate of 254 mm/s to achieve a target
longitudinal acceleration of -3.0 m/s\2\, simulating a manual brake
pedal application of a panicked driver. Test procedures for brake pedal
input characterization and verification assessment are described for
checking uniformity and to ensure the set braking magnitude and
response can be achieved.
The lead vehicle stopped test scenario requires the test subject
vehicle to be driven toward the stationary lead vehicle at 40 km/h. The
subject vehicle is to maintain its velocity and relative lateral
position to the straight testing path as it advances toward the lead
vehicle. When the time to collision is equal to 5 seconds there is a
nominal separation distance of 56 m between the front of the subject
vehicle and the rear of the lead vehicle. Once braking is initiated,
the accelerator pedal input of the subject vehicle is discontinued
fully within 0.5 seconds after the start of braking. For lead vehicle
stopped tests performed with insufficient brake pedal applications, the
brake pedal is applied at a time to collision of 1.51 seconds. The
point at which the brake pedal rate exceeds 50 mm/s is used to define
the beginning event of brake pedal input. The conclusion of testing is
marked by a collision between the subject and lead vehicle or the
subject vehicle stopping prior to colliding with the lead vehicle. The
test procedures are repeated until seven valid test trials are obtained
for each lead vehicle stopped test with and without brake pedal
applications, to obtain a total of 14 valid tests.
The test procedure for the lead vehicle moving scenario is similar
for its two vehicle speed combinations. The subject vehicle travels to
reach the target speed of 40 or 75 km/h for a minimum of 1 second; and
the lead vehicle travels at 15 or 35 km/h, respectively. Prior to
approaching the lead vehicle there should be a separation distance of
at least 100 m. Additionally, by a time to collision equal to 5
seconds, the separation range is 35 m for 40 km/h and 56 m for 75 km/h.
Once the subject vehicle encounters the lead vehicle and braking is
automatically initiated, the subject vehicle accelerator pedal was
fully released within 0.5 seconds.
The lead vehicle decelerating test procedure starts with the
subject vehicle traveling toward the lead vehicle while maintaining an
80 m separation distance. Both the subject vehicle and the lead vehicle
are required to reach and maintain a velocity of 40 km/h for at least 1
second while keeping the headway distance. Once the subject vehicle
encounters the lead vehicle and braking is initiated, the subject
vehicle accelerator pedal was fully released within 0.5 seconds. This
test procedure is repeated with similar steps for a 55 km/h velocity
and a 23 m separation distance.
In order to evaluate false positives, the steel trench plate test
scenario was executed at 40 and 75 km/h, and the stationary vehicles
test was completed at 50 km/h. For the seven test trials performed at
40 and 75 km/h, a short edge of the rectangular steel trench plate was
centered on the roadway about the x-axis. The subject vehicle was
driven toward the steel trench plate such that an initial 110.0 m
headway existed, and a nominal velocity of 40 or 75 km/h was maintained
for at least 1.0 second. The test initial test condition began when the
separation distance between the subject vehicle and steel trench plate
was 56 m and 105 m for 40 and 75 km/h, respectively. Once the subject
vehicle encountered the steel trench plate at a headway of 16.83 or
40.88 m for 40 and 75 km/h, respectively, the brakes of the subject
vehicle were engaged. The test ends when either the subject vehicle
drives over the steep trench plate or the subject vehicle stops before
crossing over the steel trench plate.
The preliminary conditions of the stationary vehicles test involved
two vehicles parked with a lateral separation of 4.5 m. These two
vehicles were faced in the forward direction of the test track and were
aligned. The subject vehicle was driven along the test track with a
100.0 m headway from the stationary vehicles. The subject vehicle was
then driven to maintain a velocity of 50 km/h for at least 1.0 second.
The starting test condition is a headway of 60 m where the steering
wheel of the subject vehicle was controlled to center the vehicle along
the test track. Once the subject vehicle encountered the stationary
vehicles at a range of approximately 23.74 m the subject vehicle
accelerator pedal was fully released within 0.5 seconds of the
initiation of braking.
6. 2021 VRTC Testing
The test track data that follows represents vehicle performance
with the latest generation AEB systems and the procedures and
conditions proposed in this NPRM largely match the procedures and
conditions used for this testing.
2021 Freightliner Cascadia
The 2021 Freightliner Cascadia was tested under the lead vehicle
stopped, lead vehicle moving, and lead vehicle decelerating scenarios
at the NHTSA VRTC in 2021. The GVT was used as the lead vehicle in
these test scenarios. The lead vehicle stopped scenario was executed at
multiple initial subject vehicle velocities from 20 km/h up to 95 km/h.
While contact with the VTD occurred at 20, 25, 30, and 35 km/h, there
were measurable speed reductions. At test velocities between 40 and 85
km/h, no collisions were observed. Collisions also occurred at 90 and
95 km/h, but the FCW at both speeds was issued earlier than 2 seconds
before contact. Ten additional test trials were conducted at 40 km/h,
and only one trial resulted in contact. Four additional test trials
were executed at 50, 60, 70, 80, and 85 km/h; in all four trials, there
were no collisions at three speeds and one collision at two speeds
(i.e., 80 and 85 km/h, respectively) which ultimately resulted in a
speed reduction when compared to the other trials.
The lead vehicle moving scenario was performed at several
combinations of subject vehicle and lead vehicle initial speeds. The
first set of eight trials
[[Page 43197]]
involved the subject vehicle at a range of velocities of 30 km/h to 90
km/h and the initial speed of the lead vehicle was 20 km/h for each.
Contact occurred only at the 30 and 60 km/h test velocities. The
initial speeds for the subject vehicle and lead vehicle for the second
set of eight trials was 40 and 15 km/h, respectively. One of these
trials ended in a collision and this run exhibited a notably lower
speed reduction when compared to the other trials. The third and fourth
sets of trials included subject vehicle and lead vehicle initial
velocity combinations of 75 and 35 km/h and 80 and 12 km/h,
respectively, and contact was avoided in all trials. For the lead
vehicle decelerating scenario collision was avoided for all trials
during the 40 km/h test. Impact occurred during four out of five runs
in the 50 km/h test with an initial headway of 18 m. However, at the
longer headway lengths of 21, 23, 25, and 40 m there were no collisions
during the 50 km/h tests. Additionally, contact was avoided for the 80
km/h test with headway lengths of 23, 25, 28, 40, and 45 m.
Table 11--2021 Freightliner Cascadia Test Track Scenarios
------------------------------------------------------------------------
Lead vehicle Subject vehicle
Scenario speed (km/h) speed (km/h)
------------------------------------------------------------------------
Lead Vehicle Stopped................. 0 20-95
Lead Vehicle Moving.................. 20 30-90
Lead Vehicle Moving.................. 15 40
Lead Vehicle Moving.................. 35 75
Lead Vehicle Moving.................. 12 80
Lead Vehicle Moving.................. 32 80
Lead Vehicle Decelerating............ 40 40
Lead Vehicle Decelerating............ 50 50
Lead Vehicle Decelerating............ 55 55
Lead Vehicle Decelerating............ 80 80
------------------------------------------------------------------------
2021 Ram 5500
The class 5 2021 Ram 5500 was tested under the lead vehicle
stopped, lead vehicle moving, and lead vehicle decelerating scenarios
at the NHTSA VRTC in 2022. The tests performed for these scenarios
involved no manual brake application; and the GVT was used as the lead
vehicle. For the lead vehicle stopped scenario, the Ram truck avoided
collisions at 10, 20, 30, 40 km/h, while impact occurred during two of
the five trials in the 50 km/h test, although there was an
approximately 80 percent reduction in speed. In general, these results
seemed to align with limitations described in the vehicle owner's
manual that indicated that the system works up to 50 km/h. Testing up
to 80 km/h was not completed to avoid damage to the subject vehicle and
test equipment. During the lead vehicle moving scenario, the truck
avoided contact at 30, 40, 50, 60, 70, and 80 km/h. Impact did occur at
90 km/h, though there was a speed reduction of 63 percent. At 50 km/h,
the lead vehicle decelerating scenario resulted in consecutive impacts
with some speed reduction. Due to the repeated collisions, testing was
discontinued to prevent damage to the subject vehicle and the GVT.
NHTSA also tested The Ram 5500 under the three scenarios with
manual brake application. The lead vehicle stopped scenario resulted in
avoidance of contact for all trials at 30, 40, and 60 km/h. Collision
did occur at 50 km/h, though there was a speed reduction of
approximately 80 percent. The lead vehicle moving scenario resulted in
impact avoidance for all 40 to 90 km/h trials, but impact did occur
during the 100 km/h test. For the lead vehicle decelerating scenario,
impact occurred during the 50 km/h test with an initial headway of 40,
32, and 23 m. Collision also occurred for the 80 km/h test with a
headway of 40 m.
Table 12--2021 Ram 5500 Test Track Scenarios
------------------------------------------------------------------------
Lead vehicle Subject vehicle
Scenario speed (km/h) speed (km/h)
------------------------------------------------------------------------
Lead Vehicle Stopped................. 0 10-60
Lead Vehicle Moving.................. 20 30-100
Lead Vehicle Decelerating............ 50 50
Lead Vehicle Decelerating............ 80 80
------------------------------------------------------------------------
In general, no single vehicle avoided collisions at all speeds in
the tested scenarios. While one vehicle may have performed better at
lower speeds and the other better at higher speeds, the combination of
results from the individual vehicles showed positive results over a
range of speeds. Overall, the performance demonstrated that the AEB
technology has improved over time, as shown in Tables 13 and
14.<SUP>71 72 73 74</SUP>
---------------------------------------------------------------------------
\71\ Phase 1--Boday, C., et al., ``Class 8 Truck-Tractor and
Motorcoach Forward Collision Warning and Automatic Emergency Braking
Test Track Research--Phase I,'' Washington, DC: National Highway
Traffic Safety Administration (June 2016). Docket No.
NHTSA[hyphen]2015-0024-0004.
\72\ Phase II- U.S. DOT/NHTSA- Class 8 Truck- Tractor and
Motorcoach Forward Collision Warning and Automatic Emergency Braking
System Test Track Research- Draft Report. Docket No. NHTSA-2015-
0024-0006.
\73\ Phase III--Salaani, M.K., Elsasser, D., Boday, C.,
``NHTSA's 2018 Heavy Vehicle Automatic Emergency Braking Test Track
Research Results,'' SAE International. J Advances & Current
Practices in Mobility 2(3):1685-1704, 2020, doi:10.4271/2020-01-
1001.
\74\ This information is available in the report titled ``NHTSA
Heavy Vehicle AEB Test Track Performance Data Summary Report--
2022,'' placed in the docket identified in the heading of this NPRM.
[[Page 43198]]
Table 13--Technology Improvement Over Time
[Class 7-8]
----------------------------------------------------------------------------------------------------------------
1st period-- 2nd period--2nd
Class 7-8 heavy vehicle capability introduction generation (2015) Current (2022)
----------------------------------------------------------------------------------------------------------------
FCW and AEB activate for moving Yes...................... Yes..................... Yes.
vehicles.
AEB can avoid contact at test No....................... Yes..................... Yes.
speeds up to 80 km/h in lead
vehicle moving scenarios.
AEB can avoid contact at test No....................... N/A..................... Yes.
speeds greater than 80 km/h in
lead vehicle moving scenarios.
FCW alerts for stopped vehicles.... Yes...................... Yes..................... Yes.
AEB activates for stopped vehicles. No....................... Yes..................... Yes.
AEB can avoid contact at test No....................... No...................... Yes.
speeds up to 80 km/h in lead
vehicle stopped scenarios.
AEB can avoid contact at test No....................... No...................... Yes.
speeds greater than 80 km/h.
----------------------------------------------------------------------------------------------------------------
Table 14--Technology Improvement Over Time
[Class 3-6]
------------------------------------------------------------------------
Class 3-6 heavy vehicle AEB
capability Up to 2015 2016-2022
------------------------------------------------------------------------
FCW and AEB activate for Yes................. Yes.
moving vehicles.
AEB can avoid contact at test No.................. Yes.
speeds up to 80 km/h in lead
vehicle moving scenarios.
AEB can avoid contact at test No.................. Yes.
speeds greater than 80 km/h
in lead vehicle moving
scenarios.
FCW alerts for stopped Yes................. Yes.
vehicles.
AEB activates for stopped No.................. Yes.
vehicles.
AEB can avoid contact at test No.................. No.
speeds up to 80 km/h in lead
vehicle stopped scenarios.
AEB can avoid contact at test No.................. No.
speeds greater than 80 km/h.
------------------------------------------------------------------------
C. NHTSA Field Study of a New Generation Heavy Vehicle AEB System
NHTSA has an ongoing field study with VTTI that aims to collect
naturalistic driving data of at least 150 heavy vehicles over a one-
year timeframe. The goal is to collect data from each driver
participant for a three-month segment of the year. This research has
very similar parameters and objectives as those described above for the
``Field Study of Heavy-Vehicle Crash Avoidance Systems'' study.
However, several years have elapsed since the data were collected for
the prior study; and the trucks included in this ongoing research
project are equipped with newer generation AEB systems, including
stationary object braking and system integration into instrument
clusters.
The data acquisition systems installed on the heavy vehicles will
allow VTTI to sample various system activations including AEB,
stationary object alerts and FCWs. The focus of the study's real-world
data collection and analysis is to ascertain an understanding of
vehicle performance, driver behavior, and driver adaptation. VTTI is
evaluating Bendix Commercial Vehicle Systems and Detroit Assurance
(Daimler) systems and the five objectives include evaluation of system
reliability, assessment of driver performance over time, assessment of
overall driving behavior, collection of data on real-world conflicts,
and generation of inputs to a safety benefits simulation model.
Preliminary results from the driver survey responses indicate that
many drivers agree that collision mitigation technology makes drivers
safer. Approximately 50 percent of drivers surveyed at least slightly
agree that AEB is beneficial and helps drivers avoid a crash.\75\
---------------------------------------------------------------------------
\75\ This information is available in a report titled ``HV AEB
Driver Exit Survey Summary as of August 31, 2022,'' which has been
placed in the docket for this rulemaking.
---------------------------------------------------------------------------
V. Need for This Proposed Rule and Guiding Principles
A. Estimating AEB System Effectiveness
In developing this NPRM, NHTSA has examined the effectiveness of
AEB, proposing only those amendments that contribute to improved crash
safety, and have considered the principles for regulatory decision-
making set forth in Executive Order 12866 (as amended), Regulatory
Planning and Review.
The effectiveness of AEB indicates the efficacy of the system in
avoiding a rear-end crash. This NPRM proposes to require heavy vehicles
to have AEB systems that enable the vehicle to completely avoid an
imminent rear-end collision under a set of test scenarios. One method
of estimating effectiveness would be to perform a statistical analysis
of real-world crash data and observe the differences in statistics
between heavy vehicles equipped with AEB and those not equipped with
AEB. However, this approach is not feasible currently due to the low
penetration rate of AEB in the on-road vehicle fleet. Consequently,
NHTSA estimated effectiveness of AEB systems using performance data
from the agency's vehicle testing. The agency assessed effectiveness
against all crash severity levels collectively, rather than for
specific crash severity levels (i.e., minor injury versus fatal).
The performance data derived from four different test vehicles was
used to estimate AEB effectiveness,\76\ and the agency is continuing
its effort to test a larger variety of vehicles to further evaluate AEB
system performance. These vehicles were subject to the same test
scenarios (stopped lead vehicle, slower-moving lead vehicle,
decelerating lead vehicle) that are proposed in this NPRM, and
effectiveness estimates are based on each vehicle's capacity to avoid a
collision during a test scenario. For example, if a vehicle avoided
colliding with a stopped lead vehicle in four out of five test runs,
its effectiveness in that scenario would be 80 percent. The test
results for each vehicle were combined
---------------------------------------------------------------------------
\76\ This information is available in the report titled ``NHTSA
Heavy Vehicle AEB Test Track Performance Data Summary Report--
2022,'' placed in the docket identified in the heading of this NPRM.
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[[Page 43199]]
into an aggregate effectiveness value by vehicle class range and crash
scenario, as displayed in Table 15.
Table 15--AEB Estimated Effectiveness (Percent)
[By vehicle class range and crash scenario]
----------------------------------------------------------------------------------------------------------------
Stopped lead Slower-moving Decelerating
Vehicle class range vehicle lead vehicle lead vehicle
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7-8............................................................ 38.5 49.2 49.2
3-6............................................................ 43.0 47.8 47.8
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As shown in Table 15, after aggregating class 7 and class 8
together, the agency has estimated AEB would avoid 38.5 percent of
rear-end crashes for the stopped lead vehicle scenario, and 49.2
percent of slower-moving and decelerating lead vehicle crashes. For
class 3-6, AEB is estimated to be 43.0 percent effective against
stopped lead vehicle crashes and 47.8 percent against slower-moving and
decelerating lead vehicle crashes. These effectiveness values are the
values NHTSA used for assessing the benefits of this proposed rule.
B. AEB Performance Over a Range of Speeds Is Necessary and Practicable
The performance requirements proposed in this NPRM are designed
around the goal of realizing as much of the safety potential of AEB
systems, while remaining realistic and practicable both economically
and technically. AEB performance guidelines created outside of the
agency's rulemaking process appear not to have been created with these
same goals, and thus may not represent the optimal balance of safety
and practicability. Several AEB performance tests developed in the
private sector are limited to a maximum test speed of around 40 km/h
(25 mph), and do not test the capability of AEB system at highway
speeds.<SUP>77 78</SUP>
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\77\ IIHS Autonomous Emergency Braking Test Protocol (Version
I). Available at <a href="https://www.iihs.org/media/a582abfb-7691-4805-81aa-16bbdf622992/REo1sA/Ratings/Protocols/current/test_protocol_aeb.pdf">https://www.iihs.org/media/a582abfb-7691-4805-81aa-16bbdf622992/REo1sA/Ratings/Protocols/current/test_protocol_aeb.pdf</a>.
(last accessed August 5, 2022).
\78\ SAE International Forward Collision Warning and Mitigation
Vehicle Test Procedure--Truck and Bus J3029_201510. (For more
details, see <a href="https://www.sae.org/standards/content/j3029_201510">https://www.sae.org/standards/content/j3029_201510</a>)
(last accessed August 5, 2022).
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NHTSA considered two primary factors in selecting the proposed test
speed ranges. The first factor is the practical ability of AEB
technology to consistently operate and avoid contact with a lead
vehicle at the widest reasonable range of speeds. A larger range of
speeds would likely yield more safety benefits and would more
thoroughly test the capabilities of the AEB system. Furthermore, as
observed in vehicle testing for NHTSA research, AEB performance during
testing at higher speeds does not necessarily indicate what the same
system's performance will be at lower speeds. For example, NHTSA's
testing of the 2021 Freightliner Cascadia truck showed that the AEB
system was able to avoid a collision with the lead vehicle at test
speeds of 40 to 85 km/h, but not at speeds below 40 km/h. Thus, testing
over a range of speeds is necessary to more fully assess AEB
performance.\79\
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\79\ This information is available in the report titled ``NHTSA
Heavy Vehicle AEB Test Track Performance Data Summary Report--
2022,'' placed in the docket identified in the heading of this NPRM.
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The second factor is the practical limit of safely conducting
vehicle tests of AEB systems. Test data indicates that AEB performance
is less consistent, becoming less likely to avoid a collision when test
speeds approach or exceed the proposed upper limits, indicating that
testing at higher speeds than proposed would be beyond technological
feasibility.\80\
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\80\ More detail on test data is discussed in the NHTSA and
FMCSA Research and Testing section.
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NHTSA's testing must be safe and repeatable as permitted by track
conditions and testing equipment. For example, if the AEB system does
not intervene as required, or if test parameters inadvertently fall
outside of the specified limits, it should be possible to safely abort
the test. In the event the subject vehicle does collide with the lead
vehicle, it should not injure the testing personnel nor cause excessive
property damage. Additionally, test tracks may be constrained by
available space and there may be insufficient space to accelerate a
heavy vehicle up to a higher speed and still have sufficient space to
perform a test. Many types of heavy vehicles are not capable of
accelerating as quickly as lighter vehicles and reaching higher test
speeds may require longer stretches that exceed available testing
facilities. At approximately 100 km/h, the agency found that
constraints with available test track length, in conjunction with the
time required to accelerate the vehicle to the desired test speed, made
performing these higher speed tests with heavy vehicles logistically
challenging.\81\ The agency has tentatively concluded that at this time
the maximum practicable test speed is 100 km/h.
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\81\ During testing of a 2021 Freightliner Cascadia at speeds
approaching 100 km/h, NHTSA experienced difficulty establishing
valid test conditions due to test facility use restrictions.
Facility use restrictions limited where emergency braking tests by
heavy vehicles and automated lead vehicle robots could co-operate,
thereby reducing the effective useable track length to less than
1100 meters.
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The maximum speed of 100 km/h is included in the test speed range
when manual braking is present; the manual braking will reduce impact
speed if the FCW issues a warning and the AEB system does not activate
before reaching the lead vehicle. This would limit potential damage to
the test equipment and avoid injury to testing personnel. With no
manual braking, the maximum test speed is 80 km/h so that in the event
that the AEB system does not provide any braking at all, damage to the
subject vehicle and test equipment is reduced and potential injuries
avoided.
The stopped lead vehicle test scenario uses a no-manual-braking
test speed range of 10-80 km/h and a manual-braking test speed range of
70-100 km/h. Similarly, the slower-moving lead vehicle test scenario
uses subject vehicle speed ranges of 40-80 km/h for no manual-braking
and 70-100 km/h for manual braking, while the lead vehicle travels
ahead at a constant speed of 20 km/h. The lower end of the subject
vehicle test speed range is 40 km/h so that the subject vehicle is
traveling faster than the lead vehicle. The decelerating lead vehicle
tests are run at either 80 or 50 km/h. This latter test is performed at
two discreet speeds rather than at ranges of speeds because the main
factors that test AEB performance are the variation of headway, or the
distance between the subject vehicle
[[Page 43200]]
and lead vehicle, and how hard the lead vehicle brakes. Also, because
these tests contain a larger number of variables requiring more complex
test choreography, limiting the test to two discreet test speeds
reduces the number of potential test conditions and reduces potential
test burden. Together, these test speed ranges provide good coverage of
the travel speeds at which heavy vehicle rear-end crashes occur in the
real world, while reducing the potential risk and damage to test
equipment and vehicles and not exceeding the practical physical size
limits of test tracks.
Additionally, the agency is proposing that these requirements would
not apply at speeds below 10 km/h. NHTSA believes that there are real-
world cases where heavy vehicles are being maneuvered intentionally in
proximity of other objects at low-speed, and AEB intervention could be
in conflict with the vehicle operator's intention. For example, if an
operator intends to drive towards the rear of another vehicle in a
parking lot in order to park the vehicle near the other, automatic
braking during this parking maneuver would be unwanted. The agency
tentatively concluded that excluding speeds below 10 km/h from the AEB
requirement would allow these types of low-speed maneuvers. This
proposal does not require AEB systems to be disabled below 10 km/h.
However, publicly available literature from at least one manufacturer
shows that some or all of the AEB system functions are not available
below 15 mph (24 km/h), indicating that current manufacturers may have
similar considerations about low-speed AEB functionality.\82\ A lower
bound for FCW and AEB activation speed of 10 km/h is also consistent
with the lower bound testing proposed for light vehicle AEB and the
Euro NCAP rating program.\83\
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\82\ Bendix Wingman Fusion Brochure, or SD-61-4963 Service Data
manual for Bendix Wingman Fusion Driver Assistance System. Available
at <a href="https://www.bendix.com/media/documents/technical_documentsproduct_literature/bulletins/SD-61-4963_US_005.pdf">https://www.bendix.com/media/documents/technical_documentsproduct_literature/bulletins/SD-61-4963_US_005.pdf</a> (last accessed August 23, 2022).
\83\ Euro NCAP Test Protocol--AEB Car-to-Car systems v3.0.3
(April 2021). See <a href="https://cdn.euroncap.com/media/62794/euro-ncap-aeb-c2c-test-protocol-v303.pdf">https://cdn.euroncap.com/media/62794/euro-ncap-aeb-c2c-test-protocol-v303.pdf</a>.
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During each test run in any of the test scenarios, the vehicle test
speed will be held constant until the test procedure specifies a
change. NHTSA is proposing that vehicle speed would be maintained
within a tolerance range of 1.6 km/h of the specified test value. In
NHTSA's experience, both the subject vehicle and lead vehicle speeds
can be reliably controlled within the 1.6 km/h tolerance range, and
speed variation within that range yields consistent test results. A
tighter speed tolerance is unnecessary for repeatability and burdensome
as it may result in a higher test-rejection rate, without any greater
assurance of accuracy of the test track performance.
NHTSA's vehicle testing suggested that the selected speed ranges
for the various scenarios are within the capabilities of at least some
recent model year AEB-equipped production vehicles.\84\ While these
current AEB systems perform a bit differently depending on the vehicle,
given that this notice proposes a lead time for manufacturers to come
into compliance with the proposed performance requirement, the agency
expects that future model year performance in accordance with a final
rule schedule will be achievable.
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\84\ This information is available in the report titled ``NHTSA
Heavy Vehicle AEB Test Track Performance Data Summary Report--
2022,'' placed in the docket identified in the heading of this NPRM.
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C. Market Penetration Varies Significantly Among Classes of Heavy
Vehicles
Though the presence of AEB in heavy vehicles has increased over the
years, many new heavy vehicles sold in the U.S. are not equipped with
AEB. Market data obtained by NHTSA indicates that although AEB is
likely equipped on the majority of class 8 vehicles and is available on
nearly all class 3 and class 4 vehicles, few of class 5 and 6 vehicles
come equipped with any type of AEB system. In addition, though the
capabilities of these AEB systems have also improved over time, there
has been no set of standardized performance metrics in the U.S. that
manufacturers could use as a benchmark to meet. This NPRM proposes
standard performance metrics that would meet a motor vehicle safety
need.
Among the variety of heavy vehicle types, class 7 and 8 truck
tractors have been the earliest to voluntarily adopt AEB systems. These
vehicles are (with some exceptions) already subject to the electronic
stability control requirement in FMVSS No. 136 and contain fewer
variations in vehicle type, configuration, and operational pattern. It
was estimated that as of 2013 only 8 to 10 percent of class 8 trucks in
the U.S. were equipped with this technology.\85\ In 2017 a FMCSA report
extrapolated available information to estimate that 12.8 percent of the
entire on-road fleet of class 8 trucks in the United States were
equipped with an AEB system,\86\ while the industry estimated that up
to 15 percent of class 8 trucks were equipped with AEB.\87\ More
recently, a survey of public information on AEB availability for heavy
vehicles reveals that this technology is becoming more prevalent on new
trucks. In 2016, Peterbilt announced the option of AEB in its class 8
model 579 truck tractor, and then made the technology standard in
2019.<SUP>88 89</SUP> As of 2017, Volvo Trucks made AEB standard
equipment on all of its class 8 truck tractor models, as a part of its
Volvo Active Driver Assist safety package.\90\ While several fleets or
manufacturers have made AEB standard, it remains an option for some
class 8 vehicles, such as the Peterbilt single-unit truck models 337
and 348.\91\ Data from a recent study indicates that the large majority
of class 8 vehicles sold from 2018 until mid-2022 had AEB as a standard
feature, and that the top ten selling class 8 vehicles all include
standard AEB.\92\
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\85\ National Transportation Safety Board. 2015. ``Special
Investigation Report: The Use of Forward Collision Avoidance Systems
to Prevent and Mitigate Rear-End Crashes.'' Report No. NTSB/SIR-15/
01 PB2015-104098. Washington, DC.
\86\ Grove, K., et al., ``Research and Testing to Accelerate
Voluntary Adoption of Automatic Emergency Braking (AEB) on
Commercial Vehicles,'' VTTI (May 2020). Available at <a href="https://rosap.ntl.bts.gov/view/dot/49335">https://rosap.ntl.bts.gov/view/dot/49335</a> (last accessed June 9, 2022).
\87\ Cannon, J., ``Automatic emergency braking is the next
generation of driver assist technologies,'' Commercial Carrier
Journal, December 14, 2017. <a href="https://www.ccjdigital.com/business/article/14936178/future-of-automatic-emergency-braking-driver-assist-tech">https://www.ccjdigital.com/business/article/14936178/future-of-automatic-emergency-braking-driver-assist-tech</a>.
\88\ <a href="https://www.peterbilt.com/about/news-events/news-releases/peterbilt-introduces-bendix-wingman-fusion-advanced-safety-system">https://www.peterbilt.com/about/news-events/news-releases/peterbilt-introduces-bendix-wingman-fusion-advanced-safety-system</a>
(last accessed August 23, 2022).
\89\ <a href="https://www.peterbilt.com/about/news-events/peterbilt-trucks-introduce-bendix-wingman-fusion-standard">https://www.peterbilt.com/about/news-events/peterbilt-trucks-introduce-bendix-wingman-fusion-standard</a> (last accessed
August 23, 2022).
\90\ https://www.volvotrucks.us/news-and-stories/press-releases/
2017/july/volvo-active-driver-assist-now-standard/
#:~:text=Volvo%20Active%20Driver%20Assist%20is%20now%20standard%20equ
ipment,is%20fully%20integrated%20with%20Volvo%E2%80%99s%20Driver%20In
formation%20Display (last accessed August 23, 2022).
\91\ <a href="https://www.peterbilt.com/about/news-events/peterbilt-announces-bendix-wingman-fusion-medium-duty">https://www.peterbilt.com/about/news-events/peterbilt-announces-bendix-wingman-fusion-medium-duty</a> (last accessed August
23, 2022).
\92\ This information is available in the S&P Global's
presentation titled ``MHCV Safety Technology Study,'' which has been
placed in the docket identified in the heading of this NPRM.
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[…truncated; see source link]Indexed from Federal Register on July 6, 2023.
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