[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 [www.gpo.gov]
[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:
     Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the online instructions for submitting 
comments.
     Mail: Docket Management Facility, M-30, U.S. Department of 
Transportation, West Building, Ground Floor, Rm. W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery or Courier: West Building, Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE, between 9 a.m. and 5 p.m. 
Eastern Time, Monday through Friday, except Federal holidays. To be 
sure someone is there to help you, please call 202-366-9332 before 
coming.
     Fax: 202-493-2251.
    Regardless of how you submit your comments, please provide the 
docket number of this document.
    Instructions: For detailed instructions on submitting comments and 
additional information on the rulemaking process, see the Public 
Participation heading of the Supplementary Information section of this 
document. Note that all comments received will be posted without change 
to https://www.regulations.gov, including any personal information 
provided.
    Privacy Act: In accordance with 5 U.S.C. 553(c), DOT solicits 
comments from the public to better inform its decision-making process. 
DOT posts these comments, without edit, including any personal 
information the commenter provides, to https://www.regulations.gov, as 
described in the system of records notice (DOT/ALL-14 FDMS), which can 
be reviewed at https://www.transportation.gov/privacy. In order to 
facilitate comment tracking and response, the agency encourages 
commenters to provide their name, or the name of their organization; 
however, submission of names is completely optional. Whether or not 
commenters identify themselves, all timely comments will be fully 
considered.
    Docket: For access to the docket to read background documents or

[[Page 43175]]

comments received, go to https://www.regulations.gov, or the street 
address listed above. To be sure someone is there to help you, please 
call 202-366-9322 before coming. Follow the online instructions for 
accessing the dockets.

FOR FURTHER INFORMATION CONTACT: 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
------------------------------------------------------------------------
    Abbreviation          Full term                   Notes
------------------------------------------------------------------------
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\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813266, https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813283, https://www.nhtsa.gov/press-releases/early-estimate-2021-
traffic-
fatalities#:~:text=Preliminary%20data%20reported%20by%20the,from%201.
34%20fatalities%20in%202020.
    \2\ https://www.transportation.gov/sites/dot.gov/files/2022-01/USDOT_National_Roadway_Safety_Strategy_0.pdf. 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.3 4 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 https://ops.fhwa.dot.gov/publications/fhwahop10014/s5.htm#f21 (Last viewed on May 5, 2022).

[[Page 43177]]



                     Table 2--Vehicle Class by GVWR
------------------------------------------------------------------------
        Vehicle class                             GVWR
------------------------------------------------------------------------
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.
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    \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.'' https://www.iso.org/standard/70133.html. 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.
---------------------------------------------------------------------------

    \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).
---------------------------------------------------------------------------

    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 2021.17 18 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\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813266;, https://www.nhtsa.gov/press-releases/early-
estimate-2021-traffic-
fatalities#:~:text=Preliminary%20data%20reported%20by%20the,from%201.
34%20fatalities%20in%202020.
    \18\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813435; https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813283; 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\ https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813251 Category II Configuration D. Rear-End.
---------------------------------------------------------------------------

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 https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/813141 (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.
---------------------------------------------------------------------------

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

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

    \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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    \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\
---------------------------------------------------------------------------

    \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 www.regulations.gov, 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. https://www.femamotorcycling.eu/wp-content/uploads/Final%20Report_motorcycle_ADAS_RDW.pdf (last accessed February 10, 
2023).
---------------------------------------------------------------------------

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

    \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. https://www.nhtsa.gov/press-releases/us-dot-and-iihs-announce-historic-commitment-20-automakers-make-automatic-emergency.
---------------------------------------------------------------------------

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\
---------------------------------------------------------------------------

    \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\
---------------------------------------------------------------------------

    \38\ Grant of petition for rulemaking, 80 FR 62487 (October 16, 
2015).
---------------------------------------------------------------------------

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.).
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

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

    \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.
---------------------------------------------------------------------------

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

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

    \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.
---------------------------------------------------------------------------

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

    \45\ https://www.transportation.gov/sites/dot.gov/files/2022-01/USDOT_National_Roadway_Safety_Strategy_0.pdf (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.
---------------------------------------------------------------------------

    \46\ NTSB Most Wanted List, https://www.ntsb.gov/Advocacy/mwl/Pages/mwl-21-22/mwl-hs-04.aspx (last accessed August 23, 2022).
---------------------------------------------------------------------------

    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:
---------------------------------------------------------------------------

    \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 https://www.ntsb.gov/safety/safety-studies/Documents/SIR1501.pdf (last accessed August 22, 2022).
---------------------------------------------------------------------------

     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:
---------------------------------------------------------------------------

    \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 https://www.ntsb.gov/investigations/AccidentReports/Reports/SIR1802.pdf (last accessed August 22, 2022).
---------------------------------------------------------------------------

     H-18-08: Require all new school buses to be equipped with 
collision avoidance systems and automatic emergency braking 
technologies.
     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.
     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 https://www.regulations.gov/document/NHTSA-2013-0067-0001.
---------------------------------------------------------------------------

    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 https://www.nhtsa.gov/sites/nhtsa.gov/files/812280_fieldstudyheavy-vehiclecas.pdf (last accessed 
June 3, 2022).
---------------------------------------------------------------------------

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

    \51\ See ``A Target Population for Automatic Emergency Braking 
in Heavy Vehicles,'' available at https://crashstats.nhtsa.dot.gov/Api/Public/Publication/812390 (last accessed June 7, 2022).
    \52\ See page 8 ``A Target Population for Automatic Emergency 
Braking in Heavy Vehicles,'' available at https://crashstats.nhtsa.dot.gov/Api/Public/Publication/812390 (last 
accessed June 7, 2022).
---------------------------------------------------------------------------

    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\
---------------------------------------------------------------------------

    \53\ See ``Large Truck Crash Causation Study,'' available at 
https://www.fmcsa.dot.gov/safety/research-and-analysis/large-truck-crash-causation-study-analysis-brief (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.
---------------------------------------------------------------------------

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

    \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 
(https://deepblue.lib.umich.edu/bitstream/handle/2027.42/107389/48532_A56.pdf?isAllowed=y&sequence=1, 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.
---------------------------------------------------------------------------

    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).
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    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\
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

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

    \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). http://www.regulations.gov, NHTSA 2012-0057-0001.
    \61\ 77 FR 39561.
---------------------------------------------------------------------------

    NHTSA considered feedback it received on the RFC and conducted 
additional testing to support further development of the test 
procedures. The agency'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\
---------------------------------------------------------------------------

    \62\ https://www.regulations.gov, NHTSA 2012-0057-0037.
    \63\ DOT HS 812 166.
    \64\ https://www.regulations.gov, NHTSA 2012-0057-0038.
---------------------------------------------------------------------------

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

    \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.
---------------------------------------------------------------------------

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

    \66\ The 2012 Freightliner was not evaluated with steel trench 
plate scenario due to the short window that the vehicle was 
available for testing.
---------------------------------------------------------------------------

    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 https://unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2013/R131e.pdf (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 https://rosap.ntl.bts.gov/view/dot/42186/dot_42186_DS1.pdf (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 
14.71 72 73 74
---------------------------------------------------------------------------

    \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.

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

[[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
----------------------------------------------------------------------------------------------------------------
7-8............................................................            38.5             49.2            49.2
3-6............................................................            43.0             47.8            47.8
----------------------------------------------------------------------------------------------------------------

    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.77 78
---------------------------------------------------------------------------

    \77\ IIHS Autonomous Emergency Braking Test Protocol (Version 
I). Available at https://www.iihs.org/media/a582abfb-7691-4805-81aa-16bbdf622992/REo1sA/Ratings/Protocols/current/test_protocol_aeb.pdf. 
(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 https://www.sae.org/standards/content/j3029_201510) 
(last accessed August 5, 2022).
---------------------------------------------------------------------------

    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\
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    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\
---------------------------------------------------------------------------

    \80\ More detail on test data is discussed in the NHTSA and 
FMCSA Research and Testing section.
---------------------------------------------------------------------------

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

    \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.
---------------------------------------------------------------------------

    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\
---------------------------------------------------------------------------

    \82\ Bendix Wingman Fusion Brochure, or SD-61-4963 Service Data 
manual for Bendix Wingman Fusion Driver Assistance System. Available 
at https://www.bendix.com/media/documents/technical_documentsproduct_literature/bulletins/SD-61-4963_US_005.pdf (last accessed August 23, 2022).
    \83\ Euro NCAP Test Protocol--AEB Car-to-Car systems v3.0.3 
(April 2021). See https://cdn.euroncap.com/media/62794/euro-ncap-aeb-c2c-test-protocol-v303.pdf.
---------------------------------------------------------------------------

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

    \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.
---------------------------------------------------------------------------

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 
2019.88 89 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 https://rosap.ntl.bts.gov/view/dot/49335 (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. https://www.ccjdigital.com/business/article/14936178/future-of-automatic-emergency-braking-driver-assist-tech.
    \88\ https://www.peterbilt.com/about/news-events/news-releases/peterbilt-introduces-bendix-wingman-fusion-advanced-safety-system 
(last accessed August 23, 2022).
    \89\ https://www.peterbilt.com/about/news-events/peterbilt-trucks-introduce-bendix-wingman-fusion-standard (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\ https://www.peterbilt.com/about/news-events/peterbilt-announces-bendix-wingman-fusion-medium-duty (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.
---------------------------------------------------------------------------

    AEB systems are also available on nearly all class 3 and 4 trucks 
that are relatively similar in size to light trucks, are manufactured 
by companies that also manufacture light vehicles, and likely have 
similar component and component suppliers as light vehicles. Although 
these vehicles are not required to have ESC systems, many of them are 
also available with ESC, likely because these vehicles are similar in 
size and use to light trucks. However, while NHTSA has information on 
ESC and AEB system availability, NHTSA has no

[[Page 43201]]

information on what percentage of class 3 and 4 vehicle purchases are 
equipped with ESC and AEB. For classes 5 and 6, there is substantially 
lower ESC and AEB system availability. However, NHTSA believes that 
this slower pace of voluntary adoption does not imply that these 
vehicles are not capable of being deployed with an AEB system. The 
system components are largely the same and have little to do with a 
vehicle's size. There are also vehicles within these classes that are 
available with ESC, and the availability of ESC has increased since 
NHTSA issued FMVSS No. 136. This market information indicates that AEB 
is practicable for all vehicles included in this proposal.

D. This NPRM Would Compel Improvements in AEB

    This rulemaking is also needed to drive improvements in AEB 
systems. The performance requirements proposed in this NPRM are 
designed around the goal of realizing as much of the safety potential 
of AEB systems as possible, while remaining realistic and practicable. 
Some contemporary AEB systems are currently designed to detect and 
mitigate collision with a vehicle ahead when travelling at a wide range 
of speeds, including interstate speeds.\93\ While the systems are also 
functional at lower speeds, the higher speed capabilities indicate that 
AEB will be capable of reducing the frequency of interstate rear-end 
crashes rather than just slower speed events.
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    \93\ See https://www.bendix.com/media/documents/technical_documentsproduct_literature/bulletins/SD-61-4963_US_005.pdf (last accessed March 1, 2023).
---------------------------------------------------------------------------

    NHTSA has tentatively concluded that the improvements to AEB 
systems by manufacturers in the absence of regulation have 
insufficiently addressed the safety problem associated with rear-end 
crashes. No individual vehicle's AEB system tested by NHTSA is 
currently capable of avoiding a collision over the range of test speeds 
that aligns with the majority of the safety problem. However, the range 
of speeds included in this proposal is practicable as at least some 
vehicles were able to achieve the desired results at each tested speed. 
While manufacturers may continue to improve AEB systems, only a 
regulation would ensure that all heavy vehicles are equipped with an 
AEB system that can avoid a collision at a range of speeds that targets 
the majority of the safety problem. Establishing performance criteria 
that meet the safety need of preventing fatalities and serious injuries 
will also ensure that the systems will be designed to address the 
serious safety problem associated with these crashes. This NPRM 
proposes that all heavy vehicles be subject to the same performance 
requirements such that the entire heavy vehicle fleet benefits from 
improvements in AEB technology.

E. BIL Section 23010(b)(2)(B)

    NHTSA is issuing this NPRM in accordance with a statutory mandate 
in BIL. Section 23010 of BIL requires the Secretary to prescribe a 
Federal motor vehicle safety standard to require all commercial 
vehicles subject to FMVSS No. 136 to be equipped with an AEB system. 
The FMVSS is 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.
    Section 23010(b)(2)(B) of BIL states that prior to prescribing the 
FMVSS for heavy vehicle AEB, the Secretary shall consult with 
representatives of commercial motor vehicle drivers regarding the 
experiences of drivers with AEB. Prior to this NPRM, NHTSA and FMCSA 
have engaged drivers and the industry more generally in various ways. 
NHTSA has published research previously that involved surveying the 
driving experiences of 18 drivers driving heavy trucks equipped with a 
prototype FCW system over a 10-month period in May 2011.\94\ NHTSA has 
also been sponsoring studies seeking input of commercial motor vehicle 
drivers. The current ongoing field study with VTTI aims to collect and 
analyze performance and operational data on newer generation AEB crash 
avoidance technologies on new, class 8 tractors by heavy vehicle 
original equipment manufacturers and their suppliers. One year of 
naturalistic driving data will be collected by monitoring the 
production systems used in real-world conditions as deployed by 
multiple fleets across the United States. In addition to the 
performance and operational data retrieved from on-board data 
acquisition systems for evaluation, the study will also involve 
conducting subjective surveys with drivers and fleet managers regarding 
performance, satisfaction, and overall acceptance of the crash 
avoidance technologies.
---------------------------------------------------------------------------

    \94\ ``Integrated Vehicle-Based Safety Systems Heavy-Truck Field 
Operational Test Independent Evaluation,'' DOT HS 811 464.
---------------------------------------------------------------------------

    FMSCA is also engaged consultation with representatives of drivers 
through the Tech-Celerate Now program.\95\ This program intends to 
accelerate the adoption of advanced crash avoidance technologies by the 
trucking industry. The first phase initiatives include national 
outreach and education. The outreach element allowed for the successful 
creation of training materials for fleets, drivers, and maintenance 
personnel related to AEB technology. Additionally, the program features 
other avenues to reach drivers including educational videos on braking, 
presentations, booth exhibitions, and webinars. As of January 2023, 
FMCSA has compiled the findings from drivers and/or representatives of 
drivers in a final report that is currently undergoing internal review. 
However, planning for the second phase has been initiated and includes 
expanding the national outreach and education campaign.
---------------------------------------------------------------------------

    \95\ Tech-Celerate Now. FMCSA. Available at https://www.fmcsa.dot.gov/Tech-CelerateNow (last accessed August 8, 2022).
---------------------------------------------------------------------------

    Building upon this and other research, NHTSA and FMCSA seek comment 
from representatives of commercial motor vehicle drivers, and from 
drivers themselves, about their experiences with AEB systems, including 
whether the AEB system prevented a crash, whether the FCW warnings were 
helpful, and whether any malfunctions or unwarranted activations 
occurred. Although members of the public should comment on all aspects 
of the NPRM they find relevant, NHTSA also request comments on the 
following specific issues:
     This proposal includes considerations that automatic 
braking is needed for safety and crash prevention. NHTSA seeks comment 
from driver experiences with AEB-equipped heavy vehicles on whether AEB 
improves heavy vehicle rear-end crash safety.
     This proposal includes warning requirements to the driver 
as part of the AEB system that braking is needed in a rear-end crash-
imminent situation. NHTSA seeks comments from driver experiences on 
whether AEB is helpful in getting a driver's attention back to the task 
of driving.
     This proposal includes requirements that automatic braking 
will occur in the event of an imminent collision on a straight testing 
path. NHTSA seeks comment on driver experiences with the performance of 
AEB when it is applied on curved roads.
     This proposal includes requirements that automatic braking 
will be tested under certain weather and roadway pavement conditions. 
NHTSA seeks comment on driver experiences when AEB is applied at the 
last moment in all weather conditions.
     This proposal includes considerations that automatic 
braking is needed because of multiple elements, including driver 
misjudgments and distractions. NHTSA seeks comment on driver 
experiences on whether the

[[Page 43202]]

application of AEB causes drivers to pay less attention to the road; or 
whether the application of AEB distracts or annoys drivers.

F. Vehicles Excluded From Braking Requirements

    The result of this proposal would require AEB and ESC on nearly all 
heavy vehicles. The only vehicles that would be excluded from AEB and 
ESC requirements would be vehicles that are already excluded from 
NHTSA's braking requirements for vehicles equipped with pneumatic 
brakes in FMVSS No. 121. This braking standard includes requirements 
for minimum stopping distance. For those vehicles, there is no 
assurance that their foundational brake systems would have the 
capability to meet the proposed AEB performance requirements, even if 
equipped with sensors capable of detecting another vehicle. These 
vehicles are also presently excluded from FMVSS No. 136 and would 
continue to be excluded under this proposal. The vehicles excluded from 
the proposed AEB and ESC requirements are:
     Any vehicle equipped with an air brake system and equipped 
with an axle that has a gross axle weight rating of 13,154 kilograms 
(29,000 pounds) or more;
     Any truck or bus that is equipped with an air brake system 
and that has a speed attainable in 3.2 km (2 miles) of not more than 53 
km/h (33 mph);
     Any truck equipped with an air brake system that has a 
speed attainable in 3.2 km (2 miles) of not more than 72 km/h (45 mph), 
an unloaded vehicle weight that is not less than 95 percent of its 
gross vehicle weight rating, and no capacity to carry occupants other 
than the driver and operating crew.
    FMCSA believes that an exemption from its ESC and AEB regulations 
is appropriate for vehicles involved in driveaway-towaway operations, 
for example, vehicles that are being transported to dealer locations or 
that are manufactured exclusively for use outside of the United States. 
Although these vehicles are operated on public roads in the United 
States when they are being transported from the point of manufacture to 
a domestic or foreign destination, these vehicles have not yet entered 
commercial service. The economic burden associated with requiring these 
vehicles to be equipped with AEB or ESC for the one-way trip out of the 
United States would certainly exceed the potential benefits.
    The driveaway-towaway exemption would also be applicable to 
vehicles being delivered to the Armed Forces of the United States. 
Vehicles operated by the military are exempt from the FMCSRs under 
Sec.  390.3(f)(2).\96\
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    \96\ FMCSA notes that the driveaway-towaway exemption provided 
in Sec.  393.56 and Sec.  393.57 is consistent with exceptions 
provided by NHTSA. Section 571.7(c) provides an exception for 
vehicles and items of equipment manufactured for, and sold directly 
to, the Armed Forces of the United States in conformity with 
contractual specifications. Section 571.7(d), through a cross-
reference to the United States Code, indicates the FMVSSs do not 
apply to motor vehicles or motor vehicle equipment intended only for 
export, labeled for export on the vehicle or equipment and on the 
outside of any container of the vehicle or equipment, and exported 
(49 U.S.C. 30112(b)(2)).
---------------------------------------------------------------------------

    FMCSA seeks comment on other types of operations for which an 
exemption from the AEB or ESC requirements may be appropriate. For 
example, what types of exemptions may be needed for CMVs with auxiliary 
equipment installed that would interfere with the operation of the AEB 
system?

VI. Heavy Vehicles Not Currently Subject to ESC Requirements

A. AEB and ESC Are Less Available on These Vehicles

    NHTSA is proposing to include nearly all vehicles with a GVWR 
greater than 4,536 kg (10,000 lbs.). This includes vehicles that are 
currently exempted from FMVSS No. 136 such as trucks other than truck 
tractors, school buses, perimeter-seating buses, transit buses, 
passenger cars, and multipurpose passenger vehicles because about half 
of the fatalities and serious injuries brought about by heavy vehicles 
are caused by class 3 through 6 vehicles.
    The FMVSSs do not currently require ESC on class 3 through 6 
vehicles or on class 7 and 8 single unit trucks, school buses, and 
certain bus types such as transit buses. ESC has not been commercially 
available for as long on class 3 through 6 vehicles as it has been for 
class 7 and 8 vehicles. However, examples can be found of manufacturers 
who offer ESC as an option on their class 3 through 6 vehicles. 
Kenworth has made AEB optional for the T880 vocational truck as well as 
for their T270 and T370 conventional class 6 trucks. Ford made ESC 
standard on its F-650 model in the 2018 model year and has made AEB 
optional on model year 2022 F-650 and F-750 class 6 trucks. A number of 
school bus manufacturers have made ESC standard on certain models, 
including ones that fall into classes 3 through 6. For example, Thomas 
Built offers ESC as standard equipment on its type C school buses, 
which can be configured to be in class 6. In some cases, ESC technology 
originating in hydraulic-brake passenger cars has moved up into the 
lower classes of heavy vehicles. For example, the 2019 Mercedes 
Sprinter, a cargo van which can be configured as a class 3 heavy 
vehicle, has ESC as standard equipment. Other class 3 and 4 vehicles 
that resemble light vehicles, such as pickup trucks, are available with 
ESC.
    The availability of ESC as an option across multiple brands and 
models within class 3 through 6 leads NHTSA tentatively to conclude 
that providing ESC is technically and economically feasible. NHTSA 
believes it is reasonable and practicable to require that ESC to be 
installed on class 3 through 6 vehicles.

B. This NPRM Proposes To Require ESC

    NHTSA has tentatively determined that ESC is necessary for safety 
to include as a foundation for an AEB requirement. Historically, the 
two technologies have been thought of as supplement or complementary 
rather joined technologies. That is, while ESC and AEB share hardware 
fundamental to both technologies, such as brake actuators, ESC is 
generally not described or advertised as a component of AEB.
    That said, despite this theoretical separation, in a survey NHTSA 
has conducted on the availability of ESC and AEB systems, NHTSA was 
unable to identify any heavy vehicle that could currently be purchased 
with an AEB system, other than an FCW-only system (i.e., not capable of 
automatic brake application), that did not also have an ESC system.\97\ 
In a 2017 white paper Bendix indicated that collision mitigation 
technology is built on a foundation of full stability. Bendix stated 
that as we look to more automated, autonomous functionality in the 
future, all of this is likely to be built on an ESC foundation as 
well.\98\ In a 2018 news release, Bendix stated that ESC provides the 
necessary platform for more advanced driver assistance systems (ADAS), 
including collision mitigation technologies.\99\ Manufacturers such as 
Ford have ESC as a must-have system for installing driver assist 
technology on the stripped commercial chassis, including AEB.\100\

[[Page 43203]]

Also, Ford has ESC and AEB as standard equipment on other chassis 
models such as the E-series models, F-650, and F-750 truck series. Ram 
Trucks also offers ESC and AEB for Chassis Cab models like RAM 3500 
trucks.101 102 Based upon these factors and its own 
understanding of the capabilities of AEB and ESC systems, NHTSA has 
tentatively concluded that there may be safety risks associated with 
the installation of an AEB system without an ESC system. For example, a 
driver who responds to an imminent collision by steering to avoid a 
collision while an AEB system is simultaneously applying braking may 
induce a lateral instability event that is not addressed by ABS, but 
that may be prevented with an ESC system. Thus, this NPRM proposes to 
require both AEB and ESC for the class 3 through 8 vehicles not 
currently subject to FMVSS No. 136.
---------------------------------------------------------------------------

    \97\ This information is available in NHTSA's VRTC class 3 to 6 
market scan for ESC-FCW-AEB spreadsheet, which has been placed in 
the docket identified in the heading of this NPRM.
    \98\ Full Stability and the Road Map to The Future- Are we still 
on the Right Road? https://www.bendix.com/media/documents/products_1/absstability/BW8055_US_000.pdf (last accessed March 3, 
2023).
    \99\ October 16, 2018. Bendix News Release, ``WORKING TOGETHER, 
BENDIX AND NORTH AMERICA'S SCHOOL BUS MANUFACTURERS ENHANCE STUDENT 
TRANSPORTATION SAFETY''.
    \100\ 2022 Ford Commercial Vehicles, F-59 Commercial Stripped 
Chassis. ESC is required for the stripped chassis Driver Assist 
Technology Package.
    \101\ ESC equipped standard on E-Series models, and F-650/F-750 
trucks, available at this link https://www.ford.com/cmslibs/content/dam/vdm_ford/live/en_us/ford/nameplate/f-650-750/2022/brochures/BRO_SUF_130E80EB-C9B2-936F-6F54-72CA6F5472CA.pdf (last viewed March 
3, 2023).
    \102\ https://www.ramtrucks.com/gab.html, ESC equipped standard 
on the RAM Chassis cab models and RAM 3500 trucks, available at this 
link (last accessed March 3, 2023).
---------------------------------------------------------------------------

    NHTSA requests comment on this tentative conclusion that ESC is 
necessary to ensure safe AEB operation or whether ESC systems are 
necessary prerequisites for AEB systems for any other reason. NHTSA 
further requests comments on specific safety scenarios where ESC 
systems would be necessary for safe operation of an AEB system.
    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 require nearly all heavy 
vehicles to have an ESC system that meets the equipment requirements, 
general system operational capability requirements, and malfunction 
detection requirements of FMVSS No. 136. The general ESC system 
operational capability requirements are the nine capabilities that are 
specified in the definition of ESC system in S4 of FMVSS No. 136, which 
include a means to augment directional stability and enhance rollover 
stability by having control over the brake systems individually at each 
wheel position and the means to control engine torque. However, NHTSA 
is not proposing test track performance requirements at this time 
because NHTSA is conscious of the potential testing burden on small 
businesses and the multi-stage vehicle manufacturers involved in class 
3 through 6 vehicle production.
    NHTSA's proposed approach would provide vehicle manufacturers the 
ability to ascertain the ESC system design most appropriate for their 
vehicles. The approach recognizes that ESC system design is dependent 
on vehicle dynamics characteristics, such as the total vehicle weight 
and location of that weight (center of gravity), which would differ 
depending on the final vehicle configuration. Vehicles not subject to 
FMVSS No. 136 include a large variety of vehicle configurations, which 
can result in numerous variations of ESC system design. The approach 
provides maximum flexibility to vehicle manufacturers to evaluate the 
characteristics of their vehicles and design an ESC system.
    In Europe, ESC was predicted to prevent about 3,000 fatalities (14 
percent), and about 50,000 injuries (6 percent) per year.\103\ In 
Europe, ESC has been mandatory for new types of vehicles since 2011, 
and for all new vehicles is mandatory since 2014.\104\ More information 
about international regulations can be found in Appendix B.
---------------------------------------------------------------------------

    \103\ Iombiller, S.F., Prado, W.B., Silva M.A. (September 15, 
2019). Comparative Analysis between American and European 
Requirements for Electronic Stability Control (ESC) Focusing on 
Commercial Vehicles. SAE International.
    \104\ July 31, 2009, Official Journal of the European Union, 
Regulation (EC) No. 661/2009, Articles 12 & 13, and Annex V.
---------------------------------------------------------------------------

C. BIL Section 23010(d)

    Section 23010 of BIL requires the Secretary to prescribe a Federal 
motor vehicle safety standard to require any commercial vehicle subject 
to FMVSS No. 136, that is manufactured after the effective date of an 
AEB standard, to be equipped with an AEB system that meets established 
performance standards. In addition, Section 23010(d) of BIL requires 
NHTSA to study equipping AEB on a variety of commercial motor vehicles 
not subject to FMVSS No. 136, including an assessment of the 
feasibility, benefits, and costs associated with installing AEB systems 
on a variety of newly manufactured commercial motor vehicles with a 
GVWR greater than 10,000 pounds. Section (d)(3) states that the 
Secretary shall issue a notice in the Federal Register containing the 
findings of the study and provide an opportunity for public comment. 
After completion of this study, the Secretary must determine whether a 
motor vehicle safety standard would meet the requirements and 
considerations described in paragraphs (a) and (b) of section 30111 of 
the Safety Act, and if the Secretary finds that an FMVSS would meet 
such requirements, initiate a rulemaking to prescribe such an FMVSS.
    This NPRM and the accompanying PRIA fulfils the mandate of section 
23010(d)(1) concerning a study on equipping commercial vehicles not 
subject to FMVSS No. 136 with AEB. Pursuant to the mandate section 
23010(d)(3) of BIL, NHTSA seeks comment on the tentative conclusions in 
this NPRM and the PRIA regarding the feasibility, benefits, and costs 
associated with installing AEB on all heavy vehicles, particularly 
class 3-6 vehicles and class 7 and 8 single-unit trucks. Further, as 
part of this rulemaking, the agency has considered whether proceeding 
with an AEB mandate for these vehicles meet the necessary provisions of 
the Safety Act, and will continue to do so in any final rule. Finally, 
although the agency notes that paragraph (d) concerns when the agency 
would be mandated to initiate a rulemaking to require AEB for these 
vehicles, that section does not affect the agency's discretionary 
ability to issue an FMVSS when it believes doing so is compelled by the 
Safety Act.

D. Multi-Stage Vehicle Manufacturers and Alterers

    Heavy vehicles include many specialty or vocational vehicles such 
as work trucks, delivery box trucks, motorhomes, and school buses, and 
the complexities within this large variety of special purpose vehicles 
make installation of ESC and AEB more challenging. These specialized 
vehicles may be produced in lower volumes with customized features to 
suit the specific needs of individual customers and in multiple stages 
by several manufacturers. Concepts and terminology relating to the 
certification of vehicles built in two or more stages (multi-stage 
vehicles) and alters are described below.
    In the typical situation, a vehicle built in two or more stages is 
one in which an incomplete vehicle, such as a chassis-cab or cut-away 
chassis built by one manufacturer, is completed by another manufacturer 
who adds work-performing or cargo-carrying components to the vehicle. 
For example, the incomplete vehicle may have a cab, but nothing built 
on the frame behind the cab. As completed, it may be a dry freight van 
(box truck), dump truck, tow truck, or plumber's truck. Like all 
vehicles that are manufactured for sale in the United States, a multi-
stage vehicle must be certified as complying with all applicable 
Federal motor

[[Page 43204]]

vehicle safety standards (FMVSS) before the vehicle is introduced into 
interstate commerce.
    Manufacturers involved in the production of multi-stage vehicles 
can include, in addition to the incomplete vehicle manufacturer, one or 
more intermediate manufacturers, who perform manufacturing operations 
on the incomplete vehicle after it has left the incomplete vehicle 
manufacturer's hands, and a final-stage manufacturer who completes the 
vehicle so that it is capable of performing its intended function.
    In some circumstances, a manufacturer at an earlier stage in the 
chain of production for a multi-stage vehicle can certify that the 
vehicle will comply with one or more FMVSS when completed, provided 
specified conditions are met. This allows what is commonly referred to 
as ``pass-through certification.'' As long as a subsequent manufacturer 
meets the conditions of the prior certification, that subsequent 
manufacturer may rely on this certification and pass it through when 
certifying the completed vehicle.
    NHTSA requests comments on how this proposal may impact multi-stage 
manufacturers and alterers. The agency seeks comment on the specific 
challenges that would be faced by the manufacturers in certifying to 
the proposed AEB or ESC or in altering a vehicle certified to the 
proposed requirements, and on whether and how NHTSA could revise this 
proposal to minimize any disproportionate impact.
    We believe that small-volume vehicle manufacturers are not likely 
to certify compliance with the proposed AEB and ESC requirements 
through their own testing but will use a combination of component 
testing by brake system suppliers and engineering judgment. Already 
much of the braking development work, including for ABS and ESC, for 
these small-volume vehicle manufacturers is done by brake suppliers. 
That is, small-volume manufacturers already must certify their vehicles 
to FMVSS Nos. 136, 105, and 121. NHTSA believes that small-volume 
manufacturers would certify to the proposed ESC and AEB requirements 
using the means they use now to certify to those braking requirements, 
which involves collaborating with their brake system suppliers, first 
and second stage manufacturers, etc. This NPRM would also provide one 
year after the last applicable date for manufacturer certification of 
compliance, in accordance with 49 CFR 571.8(b).
    NHTSA's regulations governing vehicles manufactured in two or more 
stages at 49 CFR part 568 require incomplete vehicle manufacturers to 
provide with each incomplete vehicle an incomplete vehicle document 
(IVD). This document details, with varying degrees of specificity, the 
types of future manufacturing contemplated by the incomplete vehicle 
manufacturer and must provide, for each applicable safety standard, one 
of the following three statements that a subsequent manufacturer can 
rely on when certifying compliance of the vehicle, as finally 
manufactured, to some or all of all applicable FMVSS.
    First, the IVD may state, with respect to a particular safety 
standard, that the vehicle, when completed, will conform to the 
standard if no alterations are made in identified components of the 
incomplete vehicle. This representation, which is referred to as a 
``Type 1 statement,'' is most often made with respect to chassis-cabs, 
since a significant portion of the occupant compartment in incomplete 
vehicles of that type is already complete.
    Second, the IVD may provide a statement of specific conditions of 
final manufacture under which the completed vehicle will conform to a 
particular standard or set of standards. This statement, which is 
referred to as a ``Type 2 statement,'' is applicable in those instances 
in which the incomplete vehicle manufacturer has provided all or a 
portion of the equipment needed to comply with the standard, but 
subsequent manufacturing might be expected to change the vehicle such 
that it may not comply with the standard once finally manufactured. For 
example, the incomplete vehicle could be equipped with a brake system 
that would, in many instances, enable the vehicle to comply with the 
applicable brake standard once the vehicle was complete, but that would 
not enable it to comply if the completed vehicle's weight or center of 
gravity height were altered from those specified in the IVD.
    Third, the IVD may identify those standards for which no 
representation of conformity is made because conformity with the 
standard is not substantially affected by the design of the incomplete 
vehicle. This is referred to as a ``Type 3 statement.'' A statement of 
this kind could be made, for example, by a manufacturer of a stripped 
chassis who may be unable to make any representations about conformity 
to any crashworthiness standards if the incomplete vehicle does not 
contain an occupant compartment. When it issued the original set of 
regulations regarding certification of vehicles built in two or more 
stages, the agency indicated that it believed final-stage manufacturers 
would be able to rely on the representations made in the IVDs when 
certifying the completed vehicle's compliance with all applicable 
FMVSS.
    Although the final-stage manufacturer normally certifies the 
completed vehicle's compliance with all applicable FMVSS, this 
responsibility can be assumed by any other manufacturer in the 
production chain. To take on this responsibility, the other 
manufacturer must ensure that it is identified as the vehicle 
manufacturer on the certification label that is permanently affixed to 
the vehicle. The identified manufacturer also has legal responsibility 
to provide NHTSA and vehicle owners with notification of any defect 
related to motor vehicle safety or noncompliance with an FMVSS that is 
found to exist in the vehicle, and to remedy any such defect or 
noncompliance without charge to the vehicle's owner.
    An altered vehicle is one that is completed and certified in 
accordance with the agency's regulations and then altered, other than 
by the addition, substitution, or removal of readily attachable 
components, such as mirrors or tire and rim assemblies, or by minor 
finishing operations such as painting, before the first retail sale of 
the vehicle, in such a manner as may affect the vehicle's compliance 
with one or more FMVSS or the validity of the vehicle's stated weight 
ratings or vehicle type classification. The person who performs such 
operations on a completed vehicle is referred to as a vehicle 
``alterer.'' An alterer must certify that the vehicle remains in 
compliance with all applicable FMVSS affected by the alteration.
    NHTSA seeks comment on the impacts of this NPRM on multi-stage 
manufacturers and alterers and requests comments on the following 
questions.
     Are certain multi-stage or altered vehicles manufactured 
or altered in a manner that makes it impracticable to comply with this 
proposed rule? If so, please explain which vehicles and why it is 
impracticable.
     If an incomplete vehicle were equipped with sensors for 
AEB that could become obstructed by equipment added in later 
manufacturing steps, how should NHTSA apply an AEB requirement to that 
vehicle?
     Are there any changes needed to 49 CFR part 567 or part 
568 to facilitate certification to the proposed requirements? If so, 
what would those changes be? Would a final-stage manufacturer be able 
to certify a vehicle based on the information provided by an 
intermediate or incomplete vehicle manufacturer, or is additional 
information needed in IVDs? If

[[Page 43205]]

additional information is needed, please describe the needed 
information.
     Are there any requirements in this proposal that ought not 
to apply to multi-stage vehicles or altered vehicles? Are there 
proposed requirements that should be lowered in stringency to better 
enable pass-through certification? Please provide details on those 
requirements and provide associated rationale.
     Would intermediate manufacturers, final-stage 
manufacturers, and alterers have sufficient information to identify 
when an impermissible change has been made? Please explain why or why 
not.
     Assuming there would be cases where it may not be 
practical to comply with the proposed requirements, are the existing 
exemption processes detailed in 49 CFR 555, ``Temporary exemption from 
motor vehicle safety and bumper standards,'' sufficient to accommodate 
unique vehicles, or should NHTSA explicitly consider applicability 
exclusions for certain multi-stage vehicles? If applicability 
exclusions are needed, please explain what they include and why the 
exclusion is needed. For example, should there be exclusions for 
vehicles with permanently installed work-performing equipment installed 
on the front of or extending past the front of the vehicle (e.g., auger 
trucks, bucket trucks, cable reel trucks, certain car carriers, etc.) 
or vehicles with a GVWR equal to or greater than 120,000 pounds (i.e., 
heavy haulers)?

VII. Proposed Performance Requirements

    This NPRM proposes that all heavy vehicles, class 3-8, are subject 
to the same performance requirements such that the entire heavy vehicle 
fleet benefits from improvements in AEB technology. The proposed set of 
requirements would compel AEB technology to operate at its highest 
safety potential, while at the same time being objective and 
practicable. In order to establish these requirements, the agency 
considered the key aspects of the technology and how they would best be 
applied to address the safety problem. For example, requiring AEB 
systems to perform only at lower speeds may address a significant 
portion of the rear-end crash problem, but it would not address the 
rear-end crash fatalities that mostly occur at higher speeds. Thus, 
NHTSA is proposing that AEB systems must be capable of activating 
across a wide spectrum of speeds. Similarly, the agency is aware that 
some current AEB systems may occasionally cause unwarranted braking 
events, or ``false activations,'' which could lead to unwanted 
consequences; we are thus proposing two test scenarios which vehicles 
must pass without false activation of the AEB system.
    While creating the proposed performance requirements, NHTSA 
considered the capabilities and limitations of current AEB 
technologies. Using information from vehicle testing, this proposal 
includes test scenarios and parameters that the agency found to be 
within the potential of current production vehicles. This means that at 
least one vehicle model demonstrated the ability to avoid impacting a 
lead vehicle, represented by a vehicle test device, or that it so 
nearly avoided the impact that we expect that the additional 
development time allowed by this proposal would enable the required 
improvement in performance.
    While certain requirements can be assessed without vehicle tests, a 
large portion of this proposal has performance requirements that are 
evaluated through vehicle tests. These tests, discussed in this 
section, simulate real-world scenarios and are run according to 
specified conditions and test parameters. NHTSA believes that these 
test scenarios will realistically evaluate how AEB systems perform 
while the vehicle is travelling at normal driving speeds.
    Several of the vehicle test scenarios test involve multiple moving 
vehicles. In these test scenarios, the heavy vehicle being evaluated 
with AEB is referred to as the ``subject vehicle.'' Other vehicles 
involved in the test are represented by a vehicle test device. When a 
vehicle test device is used ahead of the subject vehicle in the same 
lane, in the path of the moving subject vehicle, it is referred to as a 
``lead vehicle.'' When moving, a lead vehicle moves in the same 
direction as the subject vehicle. The speeds and relative motions of 
the subject vehicle and lead vehicle are choreographed in a variety of 
ways to represent the most common scenarios which lead to heavy vehicle 
rear-end crashes, and the test procedures measure whether the AEB 
system is able to avoid impacting the lead vehicle.
    The other vehicle tests are two false activation scenarios. A false 
activation refers to an unwarranted brake activation by the AEB system 
when there is no object present in the path of the vehicle with which 
the vehicle would collide. These two test scenarios use objects, 
including VTDs and a steel trench plate, arranged in realistic ways in 
or near the travel path but without obstructing the path. In these 
scenarios, the subject vehicle and AEB system are required to move past 
these objects without making a substantial automatic application of the 
service brakes.
    This proposal also includes system requirements that are not 
accompanied by vehicle tests. Vehicles with AEB systems must mitigate 
collision at speeds beyond the those covered by the track testing, 
ensuring robustness of the system's range of performance. The AEB 
system must include a forward collision warning (FCW) system that 
alerts the vehicle operator of an impending collision with a lead 
vehicle. Also, the system must indicate an AEB malfunction to the 
vehicle operator.

A. Proposed Requirements When Approaching a Lead Vehicle

1. Automatic Emergency Brake Application Requirements
    The agency is proposing that vehicles be required to have a forward 
collision warning system and an automatic emergency braking system that 
are able to function continuously to apply the service brakes 
automatically when a collision with a vehicle or object is imminent. 
The system must operate when the vehicle is traveling at any forward 
speed greater than 10 km/h (6.2 mph). This is a general system 
equipment requirement with no associated performance test. No specific 
speed reduction or crash avoidance would be required. However, this 
requirement is included to ensure that AEB systems are able to function 
at all times, including at speeds above those NHTSA is proposing as 
part of the performance test requirements.
    This requirement complements the performance requirements in 
several ways. While the track testing described below provides a 
representation of real-world crash events, no amount of track testing 
can fully duplicate the real world. This requirement ensures that the 
AEB's perception system identifies and automatically detects a vehicle, 
warns the driver, and applies braking when a collision is imminent. 
This requirement also ensures that AEB systems continue to function in 
environments that are not as controlled as the test track environment. 
For example, unlike during track testing, other vehicles, road users, 
and buildings may be present within the view of the sensors. Finally, 
track test equipment limitations and safety considerations limit the 
ability to test at high speeds. However, crashes still occur at higher 
travel speeds. Although generally the number of rear-end crashes 
decreases at higher travel speeds, these high-speed crashes are the 
ones that more often result in fatalities, as shown in Figure 3. The 
automatic braking requirement

[[Page 43206]]

ensures that AEB systems continue to provide safety benefits at speeds 
above those for which a track-testing requirement is currently not 
practicable, either because of performance capabilities or track test 
limitations. Where a performance standard is not practical or does not 
sufficiently meet the need for safety, NHTSA may specify an equipment 
requirement as part of an FMVSS.\105\
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    \105\ See 72 FR 17235, 17299 (Apr. 6, 2007) (discussing the 
understeer requirement in FMVSS No. 126); Chrysler Corp. v. DOT, 515 
F.2d 1053 (6th Cir. 1975) (holding that NHTSA's specification of 
dimensional requirements for rectangular headlamps constitutes an 
objective performance standard under the Safety Act).
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BILLING CODE 4910-59-C
    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 at low-speed and intentionally in proximity of other 
objects, 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. Publicly available literature from at least 
one AEB 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.\106\ NHTSA tentatively concludes that a minimum 
operational speed of 10 km/h would allow these types of low-speed 
maneuvers. This proposal would not require AEB systems to be disabled 
below 10 km/h.
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    \106\ SD-61-4963 Bendix Wingman Fusion Driver Assistance System 
Brochure, available at https://www.bendix.com/media/documents/technical_documentsproduct_literature/bulletins/SD-61-4963_US_005.pdf (last accessed June 21, 2023).
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    Enforcement of such a performance requirement can be based on 
evidence obtained by engineering investigation that might include a 
post-crash investigation and/or system design investigation. For 
instance, if a crash occurs in which the vehicle under examination has 
collided with a lead vehicle, NHTSA could investigate the details 
surrounding the crash to determine if a warning was provided and the 
automatic emergency braking system applied the service brakes 
automatically. In appropriate cases in the context of an enforcement 
proceeding, NHTSA could also use its information-gathering authority to 
obtain information from a manufacturer on the basis for its 
certification that its FCW and AEB systems meet this proposed 
requirement.
2. Forward Collision Warning Requirement
    NHTSA is proposing that AEB-equipped vehicles must have forward 
collision warning functionality that provides a warning to the vehicle 
operator if a forward collision with a lead vehicle is imminent. The 
proposal defines FCW as an auditory and visual warning provided to the 
vehicle operator that is designed to elicit an immediate crash 
avoidance response by the vehicle operator. The system must operate 
when the vehicle is traveling at any forward speed greater than 10 km/h 
(6.2 mph).
    While some vehicles are equipped with alerts that precede the FCW 
and research has examined their use, NHTSA's proposal is not specifying 
an advisory or preliminary alert that would

[[Page 43207]]

precede the FCW. Lerner, Kotwal, Lyons, and Gardner-Bonneau (1996b) 
differentiated between an imminent alert, which ``requires an immediate 
corrective action'' and a cautionary alert, which ``alerts the operator 
to a situation which requires immediate attention and may require a 
corrective action.'' \107\ A 2004 NHTSA report titled ``Safety Vehicles 
using adaptive Interface Technology (Task 9): A Literature Review of 
Safety Warning Countermeasures,'' examined the question of whether to 
include a cautionary alert level in an FCW system. Although the two FCW 
algorithms in the Automotive Collision Avoidance System Field 
Operational Test algorithms included a cautionary phase, the Collision 
Avoidance Metrics Partnership (1999) program recommended that only 
single (imminent) stage warnings be used.
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    \107\ Lerner, Kotwal, Lyons, and Gardner-Bonneau (1996). 
Preliminary Human Factors Guidelines for Crash Avoidance Warning 
Devices. DOT HS 808 342. National Highway Traffic Safety 
Administration.
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    Unlike the FCW required as part of the track testing, NHTSA is not 
specifically requiring that FCW presentation occur prior to the onset 
of braking in instances that are not tested on the track. This is to 
provide manufacturers with the flexibility to design systems that are 
most appropriate for the complexities of various crash situations, some 
of which may provide very little time for a driver to take action to 
avoid a crash. A requirement that FCW occur prior to automatic braking 
could suppress the automatic braking function in some actual driving 
scenarios, such as a lead vehicle cutting immediately in front of an 
AEB-equipped vehicle, where immediate automatic braking should not wait 
for a driver warning.
i. FCW Modalities
    Since approximately 1994, NHTSA has completed research and 
published related reports for more than 35 research efforts related to 
crash avoidance warnings or forward collision warnings. These research 
efforts, along with other published research and existing ISO standards 
(15623 and 22839) and SAE International (SAE) documents (J3029 and 
J2400) provide a basis for the proposed requirements.\108\
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    \108\ ISO 15623--Forward vehicle collision warning systems--
Performance requirements and test procedures; ISO 22839--Forward 
vehicle collision mitigation systems--Operation, performance, and 
verification requirements (applies to light and heavy vehicles); SAE 
J3029: Forward Collision Warning and Mitigation Vehicle Test 
Procedure and Minimum Performance Requirements--Truck and Bus (2015-
10; WIP currently); SAE J2400 2003-08 (Information report). Human 
Factors in Forward Collision Warning Systems: Operating 
Characteristics and User Interface Requirements.
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    NHTSA NCAP and Euro NCAP information relating to FCW was also 
considered. Since model year 2011, the agency has included FCW as a 
recommended technology in NCAP and identifies to consumers which light 
vehicles have FCW systems that meet NCAP's performance tests. NHTSA's 
March 2022 request for comments notice on proposed changes to NCAP 
sought comment on which FCW modalities or modality combinations should 
be necessary to receive NHTSA's NCAP recommendation.\109\ Commenters 
generally supported the use of a multimodal FCW strategy. The Alliance 
for Automotive Innovation and Intel both advocated allowing credit for 
any effective FCW signal type. Multiple commenters supported allowing 
NCAP credit for FCW having either auditory or haptic signals. BMW and 
Stellantis supported use of FCW auditory or haptic signals in addition 
to a visual signal. NTSB and Advocates for Highway and Auto Safety 
recommended that NHTSA conduct research examining the human-machine 
interface and examine the effectiveness of haptic warning signals 
presented in different locations (e.g., seat belt, seat pan, brake 
pulse). Dynamic Research, Inc. advocated allowing NCAP credit for 
implementation of a FCW haptic brake pulse, while ZF supported use of a 
haptic signal presented via the seat belt. Bosch warned that use of a 
haptic signal presented via the steering wheel for lane keeping or 
blind spot warning and FCW should be avoided as it may confuse the 
driver. The Alliance for Automotive Innovation raised the potential 
benefits of standardizing the warning characteristics to improve 
effectiveness as individuals move from vehicle to vehicle.
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    \109\ 87 FR 13452 (Mar. 9, 2022).
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    All current U.S. vehicle models with FCW systems appear to provide 
auditory and visual FCW signals, while only a few manufacturers also 
provide a haptic signal (e.g., seat pan vibration or a brake pulse). 
Visual FCW signals in current models consist of either a symbol or word 
(e.g., ``BRAKE!''), presented on the instrument panel or head-up 
display, and most are red.
    For this NPRM, NHTSA proposes that the FCW be presented to the 
vehicle operator via at least two sensory modalities, auditory and 
visual. Use of a multimodal warning ensures that most drivers will 
perceive the warning as soon as its presented, allowing the most time 
for the driver to take evasive action to avoid a crash. As a vehicle 
operator who is not looking toward the location of a visual warning at 
the time it is presented may not see it, NHTSA's proposal views the 
auditory warning signal as the primary modality and the visual signal 
as a secondary, confirmatory indication that explains to the driver 
what the warning was intended to communicate (i.e., a forward crash-
imminent situation). However, because hearing-impaired drivers may not 
perceive an FCW auditory signal, a visual signal is important for 
presenting the FCW to hearing-impaired individuals.
    A multimodal FCW strategy is consistent with recommendations of 
multiple U.S. and international organizations including ISO, SAE 
International, and Euro NCAP. ISO recommends a multimodal approach in 
both ISO 15623, ``Forward vehicle collision warning systems--
Performance requirements and test procedures'' and ISO 22839, ``Forward 
vehicle collision mitigation systems--Operation, performance, and 
verification requirements'' (which applies to light and heavy 
vehicles). SAE addresses the topic of a multimodal FCW strategy in both 
information report J2400 2003-08, ``Human Factors in Forward Collision 
Warning Systems: Operating Characteristics and User Interface 
Requirements,'' and J3029, ``Forward Collision Warning and Mitigation 
Vehicle Test Procedure and Minimum Performance Requirements--Truck and 
Bus (2015-10; Work in Progress currently).'' Most of these 
recommendations specify an FCW consisting of auditory and visual 
signals, while ISO 15623 specifies that an FCW include a visual 
warning, as well as an auditory or haptic signal.
ii. FCW Auditory Signal Characteristics
    The proposed FCW auditory signal would be the primary means used to 
direct the vehicle operator's attention to the forward roadway and 
should be designed to be conspicuous to quickly capture the driver's 
attention, convey a high level of urgency, and be discriminable from 
other auditory signals presented within the vehicle.\110\ Some 
specifications from NHTSA's ``Human Factors Design Guidance For 
Driver--Vehicle Interfaces'' are proposed as forward collision warning 
specifications to meet these criteria.\111\

[[Page 43208]]

As the FCW auditory signal would be the primary warning mode, this 
signal would not be permitted to be disabled.
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    \110\ DOT HS 810 697, Crash Warning System Interfaces: Human 
Factors Insights and Lessons Learned--Final Report.
    \111\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
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    To be conspicuous and quickly capture the driver's attention, the 
FCW auditory signal must ensure that the driver will readily detect the 
warning under typical driving conditions (e.g., ambient noise). The 
auditory signal must be clearly perceptible and quickly focus the 
driver's attention on the forward roadway. To ensure that the FCW 
auditory signal is conspicuous to the vehicle operator, any in-vehicle 
system or device that produces sound that may conflict with the FCW 
presentation would be required to be muted, or substantially reduced in 
volume, during the presentation of the FCW.\112\ In order for the 
warning to be detectable, a minimum intensity of 15-30 dB above the 
masked threshold (MT) should be used.113 114 115 116 Because 
sound levels inside a vehicle can vary based on any number of different 
factors, such as vehicle speed and pavement condition, NHTSA is not 
proposing a specific sound level at this time, but requests comments on 
suitable and reasonable approaches for ensuring that the FCW auditory 
signal can be detected by drivers under typical driving conditions.
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    \112\ DOT HS 810 697, Crash Warning System Interfaces: Human 
Factors Insights and Lessons Learned--Final Report.
    \113\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration. ``The amplitude of auditory signals is in the range 
of 10-30 dB above the masked threshold (MT), with a recommended 
minimum level of 15 dB above the MT (e.g., [1, 2, 3]). 
Alternatively, the signal is at least 15 dB above the ambient noise 
[3].''
    \114\ Campbell, J.L., Richman, J.B., Carney, C., and Lee, J.D. 
(2002). In-vehicle display icons and other information elements. 
Task F: Final in-vehicle symbol guidelines (FHWA-RD-03-065). 
Washington, DC: Federal Highway Administration.
    \115\ International Organization for Standardization. (2005). 
Road vehicles--Ergonomic aspects of in-vehicle presentation for 
transport information and control systems--Warning systems (ISO/TR 
16532). Geneva, Switzerland: International Organization of 
Standards.
    \116\ MIL-STD-1472F. (1998). Human engineering. Washington, DC: 
Department of Defense.
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    For communicating urgency and ensuring comprehension of auditory 
messages, fundamental frequency, the lowest frequency in a periodic 
signal, is a key design parameter.\117\ Research has shown that 
auditory warning signals with a high fundamental frequency of at least 
800 Hz more effectively communicate urgency.118 119 Greater 
perceived urgency of a warning is associated with faster reaction 
times, which would mean a quicker crash avoidance response by the 
driver.120 121 122 Therefore, NHTSA proposes that the FCW 
auditory signal's fundamental frequency must be at least 800 Hz.\123\ 
Additional proposed FCW auditory signal requirements that support 
communication of the urgency of the situation include a duty 
cycle,\124\ or percentage of time sound is present, of 0.25-0.95, and 
faster auditory signals with a tempo in the range of 6-12 pulses per 
second to be perceived as urgent and elicit rapid driver response.\125\
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    \117\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
    \118\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
    \119\ Guilluame, A., Drake, C., Rivenez, M., Pellieux, L., & 
Chastres, V. (2002). Perception of urgency and alarm design. 
Proceedings of the 8th International Conference on Auditory Display.
    \120\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
    \121\ Campbell, J.L., Richman, J.B., Carney, C., & Lee, J.D. 
(2004). In-vehicle display icons and other information elements, 
Volume I: Guidelines (Report No. FHWA-RD-03-065). Washington, DC: 
Federal Highway Administration. Available at www.fhwa.dot.gov/publications/research/safety/03065/index.cfm.
    \122\ Suied, C., Susini, P., & McAdams, S. (2008). Evaluating 
warning sound urgency with reaction times. Journal of Experimental 
Psychology: Applied, 14(3), 201-212.
    \123\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
    \124\ Duty cycle, or percentage of time sound is present, is 
equal to the total pulse duration divided by the sum of the total 
pulse duration and the sum of the inter-pulse intervals.
    \125\ Gonzalez, C., Lewis, B.A., Roberts, D.M., Pratt, S.M., & 
Baldwin, C.L. (2012). Perceived urgency and annoyance of auditory 
alerts in a driving context. Proceedings of the Human Factors and 
Ergonomics Society Annual Meeting, 56(1), 1684-1687.
---------------------------------------------------------------------------

    The FCW auditory signal needs to be easily discriminable from other 
auditory signals in the vehicle. Therefore, vehicles equipped with more 
than one crash warning type should use FCW auditory signals that are 
distinguishable from other warnings.\126\ This proposed requirement is 
consistent with ISO 15623 5.5.2.6.\127\ Standardization of FCW auditory 
signals would likely be beneficial in ensuring driver comprehension of 
the warning condition across vehicle makes and models. NHTSA invites 
comments on the feasibility of specifying a common FCW auditory signal. 
While this proposal contains no specific requirements ensuring that the 
FCW auditory signal is distinguishable from other auditory warnings in 
the vehicles, NHTSA believes that industry is likely to consider this 
in their vehicle designs as part of their due diligence and safety 
assurance.
---------------------------------------------------------------------------

    \126\ DOT HS 810 697, Crash Warning System Interfaces: Human 
Factors Insights and Lessons Learned--Final Report.
    \127\ ISO 15623--Forward vehicle collision warning systems--
Performance requirements and test procedures.
---------------------------------------------------------------------------

iii. FCW Visual Signal Characteristics
    Current FCWs in the U.S. vehicle fleet use a mix of symbols and 
words as a visual forward collision warning. Use of a common FCW symbol 
across makes and models would help to improve consumer understanding of 
the meaning of FCWs and encourage more appropriate driver responses in 
forward crash-imminent situations.
    ISO 7000, ``Graphical symbols for use on equipment--Registered 
symbols'' \128\ and the SAE J2400 (2003-08) \129\ information report, 
``Human Factors in Forward Collision Warning Systems: Operating 
Characteristics and User Interface Requirements,'' contain recommended 
FCW symbols shown in Figure 4. These symbols are similar as they both 
communicate a forward impact, while the ISO symbol portrays the forward 
impact as being specifically with another vehicle.
---------------------------------------------------------------------------

    \128\ ISO 7000--Graphical symbols for use on equipment--
Registered symbols.
    \129\ SAE J2400 (info. report, not RP or standard), 2003-08. 
Human Factors in Forward Collision Warning Systems: Operating 
Characteristics and User Interface Requirements.

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[[Page 43209]]

[GRAPHIC] [TIFF OMITTED] TP06JY23.004

    Because the symbol in SAE J2400 relates the idea of a frontal crash 
without depicting a particular forward object, this symbol could 
visually represent and apply to scenarios when approaching a lead 
vehicle but also scenarios approaching pedestrians or other objects 
which may be relevant to AEB systems. To prevent different vehicle 
types from having different FCW alerts, NHTSA proposes the same FCW 
characteristics and reasoning in both the light vehicle NPRM and this 
NPRM. Therefore, NHTSA has taken account of considerations for 
pedestrian scenarios, because the light vehicle proposed rule contains 
a requirement that FCW and AEB systems function in the case of an 
imminent collision with a pedestrian. NHTSA finds the SAE J2400 symbol 
to be most applicable to the FCW requirements in this proposal. NHTSA 
proposes that FCW visual signals using a symbol must use the SAE J2400 
(2003-08) symbol.
    Some other vehicle models employ a word-based visual warning, such 
as ``STOP!'' or ``BRAKE!'' SAE J2400 also includes a word-based visual 
warning recommendation consisting of the word, ``WARNING.'' A well-
designed warning should instruct people about what to do or what not to 
do to avoid a hazard. The potential benefit of a word-based warning for 
FCW is that it can communicate to the driver an instruction about what 
to do to avoid or mitigate the crash, thereby expediting the driver's 
initiation of an appropriate crash avoidance response. However, 
Consumer Reports noted in its online ``Guide to forward collision 
warning'' that for some models, visual warning word use was found to be 
confusing to some drivers surveyed.\130\ Respondents reported a common 
complaint that ``their vehicle would issue a visual ``BRAKE'' alert on 
the dash, but it wouldn't bring the car to a stop . . .'' This 
confusion as to whether the word is meant to communicate what the 
driver should do or what the vehicle is doing may stem from drivers 
assuming that any information presented within the instrument panel 
area is communicating something relating to the vehicle's condition or 
state, as symbols presented in that location generally do. Presenting a 
word-based warning in a higher location away from the instrument panel, 
as recommended by SAE J2400, may be interpreted more accurately by 
drivers as well as increase the likelihood of FCW visual warning 
perception by drivers.\131\ NHTSA requests comments on this issue and 
any available objective research data that relates to the effectiveness 
of word-based FCW visual signals in instrument panel versus head-up 
display locations. NHTSA also requests comments regarding whether 
permitting word-based warnings that are customizable in terms of 
language settings is necessary to ensure warning comprehension by all 
drivers.
---------------------------------------------------------------------------

    \130\ ``Guide to forward collision warning: How FCW helps 
drivers avoid accidents.'' Consumer Reports. https://www.consumerreports.org/car-safety/forward-collision-warning-guide/ 
(last accessed April 2022).
    \131\ SAE J2400 2003-08 (Information report). Human Factors in 
Forward Collision Warning Systems: Operating Characteristics and 
User Interface Requirements.
---------------------------------------------------------------------------

    One plausible benefit of a word-based visual warning is that some 
word choices that instruct the driver to initiate a particular action, 
such as ``STOP!,'' would be fully applicable to lead vehicles and other 
obstacles or pedestrians, whereas a symbol containing an image of a 
lead vehicle would not be directly applicable to other crash-imminent 
scenarios. Although this NPRM does not propose requiring pedestrian 
AEB, NHTSA believes the warning should not be directed specifically at 
lead vehicle AEB. As the response desired from the driver, to apply the 
brakes, the content of the visual warning need not be specific to the 
type of forward obstacle, but needs simply to communicate the idea of 
an impending forward crash. NHTSA requests comments and any available 
research data regarding the use and effectiveness of obstacle-specific 
symbols and word-based visual warnings and the relative effectiveness 
of word-based visual warnings compared to symbols.
    While many current vehicle models present a visual FCW signal 
within the instrument panel, drawing a driver's eyes downward away from 
the roadway to the instrument panel during a forward crash-imminent 
situation is likely to have a negative impact on the effectiveness of 
the driver's response to the FCW. Research indicates that a visual FCW 
signal presented in the instrument panel can slow driver response.\132\ 
The research findings support the SAE J2400 recommendation advising 
against the use of instrument panel based visual FCWs.\133\ SAE J2400 
(2003-08) states:
---------------------------------------------------------------------------

    \132\ ``Evaluation of Forward Collision Warning System Visual 
Alert Candidates and SAE J2400,'' SAE Paper No. 2009-01-0547, 
https://trid.trb.org/view/1430473.
    \133\ SAE J2400 2003-08 (Information report). Human Factors in 
Forward Collision Warning Systems: Operating Characteristics and 
User Interface Requirements.

    Visual warnings shall be located within a 10-degree cone of the 
driver's line of sight. Qualitatively, this generally implies a top-
of-dashboard or head-up display location. A conventional dashboard 
location shall not be used for the visual warning. The rationale for 
this is based on the possibility that an instrument panel-based 
---------------------------------------------------------------------------
visual warning may distract the driver from the hazard ahead.

    This FCW visual signal location guidance is also consistent with 
ISO 15623, which states that the FCW visual signal shall be presented 
in the ``main glance direction.'' Current vehicles equipped with head-
up displays have the ability to present a FCW visual signal within the 
driver's forward field of view. Furthermore, some GM vehicles not 
equipped with head-up displays currently have the ability to present a 
FCW visual signal reflected onto the

[[Page 43210]]

windshield in the driver's forward line-of-sight. Despite the FCW 
visual signal being considered secondary to the auditory signal, NHTSA 
agrees that the effectiveness of a FCW visual signal would be maximized 
for both hearing and hearing-impaired drivers if the signal is 
presented at a location within the driver's forward field of view above 
the instrument panel. To ensure maximum conspicuity of the FCW visual 
signal (be it word-based or a symbol), NHTSA proposes that it be 
presented within a 10-degree cone of the driver's line of sight. The 
line of sight would be based on the forward-looking eye midpoint 
(Mf) as described in FMVSS No. 111, ``Rear visibility,'' 
S14.1.5.
    The FCW visual signal would be required to be red as is generally 
used to communicate a dangerous condition and as recommended by ISO 
15623 and SAE J2400 (2003-08). Because the FCW visual signal is 
intended to be confirmatory for the majority of drivers, the symbol 
would be required to be steady burning.
iv. FCW Haptic Signal Discussion
    NHTSA considered also specifying a complementary haptic FCW signal 
as part of the proposed FCW specifications. Currently, only a portion 
of U.S. vehicles equipped with forward collision warning include a 
haptic warning component. For example, General Motors vehicles equipped 
with the haptic warning feature can present either a haptic seat pulse 
(vibration) or auditory warning based on a driver-selectable setting. 
Some other vehicle manufacturers, such as Stellantis and Audi, use a 
brake pulse, or brief deceleration of the vehicle, as part of the FCW. 
Some Hyundai/Kia models incorporate a haptic steering wheel vibration 
into the FCW. As haptic steering wheel signals are used by many lane 
keeping features of current vehicles to encourage drivers to steer the 
vehicle back toward the center of the lane, providing a haptic FCW 
signal via the steering wheel may result in driver confusion and be 
less effective in eliciting a timely and beneficial driver response.
    ISO 15623 allows a haptic signal as an alternative to an auditory 
signal.\134\ It permits a haptic brake pulse warning with a duration of 
less than 1 second when the driver is not already applying the brakes. 
ISO 15623 also allows actuation of a seat belt pretensioner as a haptic 
FCW signal.
---------------------------------------------------------------------------

    \134\ ISO 15623--Forward vehicle collision warning systems--
Performance requirements and test procedures.
---------------------------------------------------------------------------

    Some research has shown that haptic FCW signals can improve crash 
avoidance response. NHTSA research on ``Driver-Vehicle Interfaces for 
Advanced Crash Warning Systems'' found that a haptic signal delivered 
via the seat belt pretensioner would be beneficial in eliciting an 
effective crash avoidance response from the vehicle operator. The 
research showed for FCWs issued at 2.1-s time to collision (TTC) that 
seat belt pretensioner-based FCW signals elicited the most effective 
crash avoidance performance.\135\ Haptic FCW signals led to faster 
driver response times than did auditory tonal signals. FCW modality had 
a significant effect on participant reaction times and on the speed 
reductions resulting from participants' avoidance maneuvers (regardless 
of whether a collision ultimately occurred). Brake pulsing or seat belt 
tensioning were found to be effective for returning distracted drivers' 
attention to the forward roadway and eliciting desirable vehicle 
control responses; seat vibration similar to a virtual rumble strip 
(vibrating the front of the seat) was not found to rapidly and reliably 
return driver attention to the forward roadway within the research. 
Similarly, research by Aust (2014) found that ``combining sound with 
seat belt jerks or a brake pulse leads to significantly faster response 
times than combining the sound with a visual warning'' and stated, 
``these results suggest that future FCWs should include a haptic 
modality to improve driver performance.'' \136\ Aust (2014) also found 
use of a haptic seat belt FCW signal to be slightly more effective (100 
ms faster driver response) than a haptic brake pulse in one of two 
scenarios (response times were equal in a second scenario). Despite 
these promising research results associated with use of a seat belt 
based FCW haptic component, NHTSA was unable to identify any current 
U.S. vehicle models equipped with a haptic seat belt FCW component.
---------------------------------------------------------------------------

    \135\ Lerner, N., Singer, J., Huey, R., Brown, T., Marshall, D., 
Chrysler, S., . . . & Chiang, D.P. (2015, November). Driver-vehicle 
interfaces for advanced crash warning systems: Research on 
evaluation methods and warning signals. (Report No. DOT HS 812 208). 
Washington, DC: National Highway Traffic Safety Administration.
    \136\ Aust, M. (2014) Effects of Haptic Versus Visual Modalities 
When Combined With Sound in Forward Collision Warnings. Driving 
Simulation Conference 2014, Paper number 36. Paris, France, 
September 4-5, 2014.
---------------------------------------------------------------------------

    Other studies found FCW haptic brake pulses effective at getting a 
driver's attention and that drivers are more likely to detect a brake 
pulse if it produces a sensation of ``jerk'' or ``self-motion.'' 
137 138 Kolke reported reaction times shortened by one-third 
(approximately 0.3 s, non-significant) when a brake pulse was added to 
an audio-visual warning.\139\ One usability drawback is that drivers 
tend to report that vehicle brake pulses are too disruptive, which can 
lead to unfavorable annoyance.\140\
---------------------------------------------------------------------------

    \137\ Lee, J.D., McGehee, D.V., Brown, T.L., & Nakamoto, J. 
(2012). Driver sensitivity to brake pulse duration and magnitude. 
Ergonomics, 50(6), 828-836.
    \138\ Brown, S.B., Lee, S.E., Perez, M.A., Doerzaph, Z.R., 
Neale, V.L., & Dingus, T.A. (2005). Effects of haptic brake pulse 
warnings on driver behavior during an intersection approach. 
Proceedings of the Human Factors and Ergonomics Society 49th Annual 
Meeting, 1892-1896.
    \139\ Kolke, Gauss, and Silvestro (2012). Accident reduction 
through emergency braking systems in passenger cars. Presentation at 
the 8th ADAC/BASt-Symposium ``Driving Safely in Europe.'' October 5, 
2012, Workshop B.
    \140\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
---------------------------------------------------------------------------

    Presentation of a FCW haptic signal via the driver's seat pan has 
also been investigated. NHTSA's ``Human factors design guidance for 
driver-vehicle interfaces'' contains best practice information for 
implementation of haptic displays, including ``Generating a Detectable 
Signal in a Vibrotactile Seat.'' \141\ In a large-scale field test of 
FCW and LDW systems on model year 2013 Chevrolet and Cadillac vehicles, 
the University of Michigan Transportation Research Institute and GM 
found that GM's Safety Alert Seat, which provides haptic seat vibration 
pulses, increases driver acceptance of both FCW and LDW systems 
compared to auditory signals.\142\
---------------------------------------------------------------------------

    \141\ Campbell, J.L., Brown. J.L., Graving, J.S., Richard, C.M., 
Lichty, M.G., Sanquist, T., . . . & Morgan, J.L. (2016, December). 
Human factors design guidance for driver-vehicle interfaces (Report 
No. DOT HS 812 360). Washington, DC: National Highway Traffic Safety 
Administration.
    \142\ Flannagan, C., LeBlanc, D., Bogard, S., Nobukawa, K., 
Narayanaswamy, P., Leslie, A., Kiefer, R., Marchione, M., Beck, C., 
and Lobes, K. (2016, February), Large-scale field test of forward 
collision alert and lane departure warning systems (Report No. DOT 
HS 812 247), Washington, DC: National Highway Traffic Safety 
Administration.
---------------------------------------------------------------------------

    NHTSA's March 2022 request for comments notice on the NCAP sought 
comment on which FCW modalities or modality combinations should receive 
credit and asked specific questions regarding haptic signals and 
whether certain types should be excluded from consideration (e.g., 
because they may be such a nuisance to drivers that they are more 
likely to disable the FCW or AEB system). A preliminary review of 
comments on that notice found multiple comments highlighting a need for 
more

[[Page 43211]]

research relating to FCW signals. The National Transportation Safety 
Board highlighted a need for additional information regarding haptic 
signals presented in different locations stating ``[w]ithout examining 
the efficacy of different means of providing haptic alerts and defining 
appropriate, research-supported implementations, a prudent approach 
would give credit only for audible unimodal alerts or for bi-modal 
alerts that include audible alerts.'' Rivian stated ``[t]he agency 
should award credit to systems that provide both audible and haptic 
alerts and provide the option to turn either of them OFF based on 
driver preference. These audible or haptic alerts should be in sync 
with providing a visual alert of an impending collision. The agency 
should recommend the decibel level and the haptic feedback location and 
type as a baseline and based on research on reducing nuisance to the 
driver.''
    Given the lack of consensus within available research as to the 
best location for a FCW haptic signal (seat belt, seat pan, steering 
wheel, or brake pulse), and NHTSA's ongoing review of comments 
submitted in response to the March 2022 request for comments, NHTSA is 
not at this time proposing to require a haptic FCW component, but 
invites comment on whether requiring FCW to contain a haptic component 
presented via any location may increase FCW effectiveness or whether a 
FCW haptic signal presented in only one specific, standardized location 
should be allowed.
    While the FCW auditory signal is envisioned as being the primary 
means of warning the driver, providing a haptic FCW signal that would 
complement or supplant the auditory warning signal would likely improve 
FCW perception for hearing-impaired drivers. Some drivers also may 
prefer an alternative modality to auditory warnings (e.g., due to 
annoyance caused by the auditory warning). However, the degree of 
additional benefit that may be accrued by requiring a haptic FCW signal 
in addition to a well-designed auditory and visual FCW that meets the 
specifications proposed is not known.
    A haptic FCW signal, to be effective, would necessarily require the 
driver to be in physical contact with the vehicle component through 
which the haptic signal is presented in order to perceive the warning. 
For example, if the driver is not wearing a seat belt, a haptic FCW 
signal presented via the seat belt would not be effectively received. A 
seat pan based haptic FCW signal would be unlikely to have such a non-
contact issue. NHTSA is interested in research data documenting the 
comparison of a compliant auditory-visual FCW to that same FCW with an 
added haptic component. NHTSA also welcomes any objective data 
documenting the relative effectiveness of different haptic signal 
presentation locations for FCW use.
3. Performance Test Requirements
    This NPRM would require that, when approaching a lead vehicle 
during testing, the subject vehicle must provide a forward collision 
warning and subsequently apply the brakes to avoid a collision. This 
performance requirement is conducted under a defined set of conditions, 
parameters (e.g., relative vehicle speeds and distances), and test 
procedures.
    For all vehicle tests where the subject vehicle approaches a lead 
vehicle, NHTSA is proposing that the minimum performance requirement is 
complete avoidance of the lead vehicle. NHTSA chose the performance 
criterion of collision avoidance because it maximizes the safety 
benefits of the rule as compared to a metric that might permit a 
reduced speed collision. NHTSA has tentatively concluded that a no-
contact criterion for the performance test requirements is practicable 
to achieve, consistent with the need for safety, and may be necessary 
to ensure test repeatability.
    NHTSA also seeks comment on the potential consequences if vehicle 
contact were allowed during testing. First, NHTSA seeks comment on how 
allowing contact during testing would affect the safety benefits of AEB 
systems. Second, NHTSA seeks comment on whether allowing contact during 
testing would create additional testing burdens. Specifically, NHTSA is 
concerned that any performance test requirement that allows for vehicle 
contact not resulting in immediate test failure could result in the 
non-repeatability of testing without expensive or time-consuming 
interruptions to testing, and seeks comment on this concern. For 
instance, if a test vehicle were to strike the lead vehicle test 
device, even at a low speed, sensors on the vehicle could become 
misaligned or the vehicle test device may be damaged, including in ways 
that are not immediately observable. For example, damage to the test 
device might affect the radar cross section that requires a long 
verification procedure to discover.
4. Performance Test Scenarios
    NHTSA is proposing three track test scenarios to evaluate AEB 
performance. The test scenarios have the subject vehicle travelling 
toward a lead vehicle which is ahead in the same lane. However, the 
lead vehicle may be either stopped, moving at a constant but slower 
speed, or decelerating to a stop.
    These three tests were chosen because they represent the three most 
common pre-crash scenarios involving a lead vehicle. A NHTSA research 
study of heavy vehicles comprising the striking vehicle in rear-end 
crashes in the United States determined that four pre-crash scenarios 
exist in data of both fatal and non-fatal crashes.\143\ These four 
scenarios include the three listed above, and also a ``cut-in'' case in 
which a lead vehicle changed lanes or merged into the path of the heavy 
vehicle just prior to the crash. The cut-in scenario was excluded from 
the test scenarios for this proposal because the research study shows 
that it was much less likely to occur than the other three 
scenarios.\144\
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    \143\ Woodrooffe, J., et al. ``Performance Characterization and 
Safety Effectiveness Estimates of Forward Collision Avoidance and 
Mitigation Systems for Medium/Heavy Commercial Vehicles,'' Pg. 12. 
Report No. UMTRI-2011-36, UMTRI (August 2012). Available at https://www.regulations.gov/document/NHTSA-2013-0067-0001 (last accessed 
June 9, 2022).
    \144\ The cut-in scenario represents less than 5% of the pre-
crash scenarios.
---------------------------------------------------------------------------

i. Stopped Lead Vehicle
    This test recreates a roadway scenario where the subject vehicle 
encounters a lead vehicle which is stopped ahead in the same lane. 
Figure 5 shows the basic setup for the stopped lead vehicle scenario. 
The subject vehicle is driven toward the stationary lead vehicle at a 
constant speed, and the accelerator is only released if a forward 
collision warning is issued. The test ends when the subject vehicle 
either automatically stops without impact, or proceeds to strike the 
lead vehicle.
    NHTSA proposes testing under two conditions for the subject 
vehicle: testing without any manual brake application (to test the CIB 
component) and testing with manual brake application (to ensure that 
the driver's application of the brake pedal does not inhibit the 
functionality of the AEB system). Testing with no brake application 
simulates a driver who does not intervene in response to an FCW alert 
prior to a crash. Testing with brake application simulates a driver who 
applies the brakes, but the manual brake application is insufficient to 
prevent a collision.
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[[Page 43212]]

[GRAPHIC] [TIFF OMITTED] TP06JY23.005

ii. Slower-Moving Lead Vehicle
    This test recreates a roadway scenario where the subject vehicle 
encounters a lead vehicle that is moving at a constant but slower speed 
ahead in the same lane. Figure 6 shows the basic setup for the slower-
moving lead vehicle scenario. The subject vehicle is driven toward the 
lead vehicle at a constant speed, and its accelerator is then released 
after the AEB system in the subject vehicle issues a forward collision 
warning. The test ends when the subject vehicle either slows down to a 
speed less than or equal to the lead vehicle's speed without impact or 
strikes the lead vehicle. As with the stopped lead vehicle test, NHTSA 
proposes testing under two conditions for the subject vehicle: without 
any manual brake application and with manual brake application.
[GRAPHIC] [TIFF OMITTED] TP06JY23.006

iii. Decelerating Lead Vehicle
    This test recreates a roadway scenario where the subject vehicles 
encounter a lead vehicle that is slowing down ahead in the same lane. 
At the start of the test, both the subject vehicle and lead vehicle 
travel at the same constant speed, while maintaining a predetermined 
relative distance, or headway. The lead vehicle then begins to 
decelerate, reducing the headway. Once the AEB system in the subject 
vehicle issues a forward collision warning, the subject vehicle's 
accelerator is released. The test ends when the subject vehicle either 
automatically stops without impact or strikes the lead vehicle. As with 
the prior two tests, NHTSA proposes testing under two conditions for 
the subject vehicle: without any manual brake application and with 
manual brake application. Figure 7 shows the basic setup for the 
decelerating lead vehicle scenario.
[GRAPHIC] [TIFF OMITTED] TP06JY23.007

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[[Page 43213]]

5. Parameters for Vehicle Tests
    The test procedures for each scenario reference a set of 
parameters. These parameters are presented in Table 16, where each row 
represents a potential combination of parameters to be used for a test 
run. The parameters define the speeds, decelerations, headways, and 
manual brake applications used for the choreography of the vehicle test 
scenarios. Specifically, these include:

 Subject Vehicle Speed (VSV)--speed at which the 
subject vehicle travels toward the lead vehicle
 Lead Vehicle Travel Speed (VLV)--speed at which the 
lead vehicle travels in the same direction as the subject vehicle
 Headway--the distance between the subject vehicle and the lead 
vehicle
 Lead Vehicle Deceleration--the rate at which the lead vehicle 
reduces its speed
 Manual Brake Application--specifies whether or not the service 
brakes of the subject vehicle will be applied ``manually,'' or via a 
brake controller

                                                Table 16--Test Parameters When Approaching a Lead Vehicle
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                  Speed (km/h)
          Test scenarios           ------------------------------------------        Headway (m)        Lead vehicle decel. (g)        Manual brake
                                               VSV                  VLV                                                                application
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stopped Lead Vehicle..............  Any 10-80...............               0  ........................  .......................  no.
                                    Any 70-100..............               0  ........................  .......................  yes.
Slower-Moving Lead Vehicle........  Any 40-80...............              20  ........................  .......................  no.
                                    Any 70-100..............              20  ........................  .......................  yes.
Decelerating Lead Vehicle.........  50......................              50  Any 21-40...............  Any 0.3-0.4............  no.
                                    50......................              50  Any 21-40...............  Any 0.3-0.4............  yes.
                                    80......................              80  Any 28-40...............  Any 0.3-0.4............  no.
                                    80......................              80  Any 28-40...............  Any 0.3-0.4............  yes.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Some of these parameters are proposed as ranges.\145\ The use of 
ranges allows NHTSA to ensure AEB system performance remains consistent 
under a variety of conditions and that no substantial degradation in 
performance occurs at any point within the range. NHTSA tentatively 
concludes that requiring a minimum performance only at discreet, 
predetermined values within these proposed ranges may not ensure that 
AEB system performance is sufficiently robust to meet the need for 
safety.
---------------------------------------------------------------------------

    \145\ In instances where an FMVSS includes a range of values for 
testing and/or performance requirements, the use of the word ``any'' 
is consistent with 49 CFR 571.4.
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i. Vehicle Speed Parameters
    The proposed test speed ranges were selected considering two 
primary factors. 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 could yield more safety benefits. Also, a larger range of speeds 
will more thoroughly test the capabilities of the AEB system. NHTSA, 
through its understanding of vehicle braking systems described in 
established standards such as FMVSS Nos. 105 and 121, knows that 
testing stopping distance at 60 mph is indicative of the service brake 
performance over a range of speeds, and in those cases testing at a 
single speed is acceptable. However, as observed in vehicle testing for 
NHTSA research, AEB performance during testing at interstate speeds 
does not necessarily indicate what the same system's performance will 
be at lower speeds. Thus, NHTSA tentatively concludes that testing over 
a range of speeds is necessary to fully assess AEB performance.
    The second factor is the practical limit of safely conducting 
vehicle tests of AEB systems. 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, the test should be designed 
so that it does so in a manner that will 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 high 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 high test speeds may require long distances that exceed 
what is available at many vehicle 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 high speed tests with 
heavy vehicles logistically challenging.\146\ The agency has 
tentatively concluded that at this time the maximum practicable test 
speed is 100 km/h.
---------------------------------------------------------------------------

    \146\ During testing of a 2021 Freightliner Cascadia at speeds 
approaching 100 km/h, NHTSA experienced difficulty establishing 
valid test conditions due to insufficient track length.
---------------------------------------------------------------------------

    The maximum speed of 100 km/h is included in the test speed range 
when manual braking is present; the manual braking will guarantee a 
speed reduction even if the AEB system does not activate before 
reaching the lead vehicle, which would limit potential damage to the 
test equipment and reduce other potential risks. When no manual braking 
is allowed, the maximum test speed would be 80 km/h so that, in the 
event the AEB system does not provide any braking at all, risk to 
personnel and damage to test equipment are reduced. Over 82 percent of 
rear-end crashes where the heavy vehicle is the striking vehicle occur 
at speeds below 80 km/h.\147\ However, the majority of fatal crashes 
occur at speeds above 80 km/h, and approximately 40 percent of these 
occur at travel speeds between 80 and 100 km/h. The stopped lead 
vehicle test scenario uses a no-manual-braking test speed range of 10 
to 80 km/h and a manual-braking test speed range of 70 to 100 km/h. 
Together, these test speed ranges overlap with 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

[[Page 43214]]

exceeding the practical physical size limits of test tracks.
---------------------------------------------------------------------------

    \147\ This is based on analysis of 2017-2019 crash data.
---------------------------------------------------------------------------

    Similarly, the slower-moving lead vehicle test scenario uses speed 
ranges of 40 to 80 km/h and 70 to 100 km/h for the subject vehicle, 
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 50 or 80 km/h. This 
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 and 
lead vehicle, and how hard the lead vehicle brakes. Additionally, 
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.
    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 chosen test value. This is 
important for test consistency. Vehicle speed determines the time to 
collision, which is a critical variable in AEB tests. 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 burdensome and unnecessary for repeatability 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. For example, the 
2021 Freightliner Cascadia avoided collision in the stopped lead 
vehicle test at all speeds between 40 and 85 km/h, most speeds between 
30 and 90 km/h (except 30 and 60 km/h) in the slower-moving lead 
vehicle test, and in all decelerating lead vehicle tests that were run 
at the proposed parameters. This vehicle's AEB system did not prevent a 
collision at lower speeds between 20 and 35 km/h for the stopped lead 
vehicle test. However, the 2021 Dodge Ram 550 avoided collision in all 
stopped lead vehicle tests from 10 to 40 km/h. In many test cases where 
current AEB systems did not prevent a collision, the AEB significantly 
reduced the speed before the collision. 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 
compliance with these requirements would be achievable.
ii. Headway
    The decelerating lead vehicle test scenario includes a parameter 
defining how far ahead the lead vehicle is from the subject vehicle at 
the beginning of the test, which is referred to as headway. Headway and 
lead vehicle deceleration are the main factors for the dynamics of the 
decelerating lead vehicle test since both the lead and subject vehicles 
start the test at the same constant speed. At the start of the test, 
when the vehicles are both travelling at 50 km/h, the proposed headway 
specification is any distance between 21 m and 40 m.\148\ When the 
vehicles are both travelling at 80 km/h, the proposed headway 
specification is any distance between 28 m and 40 m. Headways are 
proposed as a range in order to assure AEB functionality over a wider 
range of driving scenarios. A basic kinematic simulation of heavy 
vehicle AEB braking under the proposed test parameters, assuming 
factors such as AEB response time and foundation brake reaction time/
deceleration similar to what was observed in testing, indicated that 
headways shorter than 21 and 28 m would not be realistic to achieve and 
would inevitably result in a collision.
---------------------------------------------------------------------------

    \148\ The bounds of the headway range are consistent with the 
headways in the April 2021 European New Car Assessment Programme 
(Euro NCAP), Test Protocol--AEB Car-to-Car systems, Version 3.0.3 
for the same scenario.
---------------------------------------------------------------------------

    The upper limit of 40 m was chosen because testing at longer 
headways does not provide additional insight into AEB performance with 
regard to decelerating lead vehicles. At headways greater than 40 m, 
the lead vehicle decelerating may come to a full stop prior to the 
subject vehicle actuating the brakes. This essentially becomes a 
stopped lead vehicle test. Allowing for a range of headways during 
testing also makes the choreography of the test possible by providing a 
tolerance for the headway. At the start of the test, the speed of both 
the subject vehicle and lead vehicle are the same and are maintained 
within the tolerance specified (plus or minus 1.6 km/h). As each 
vehicle's speed fluctuates a bit differently within these bounds, in 
turn the headway between the vehicles accordingly fluctuates as well. 
As long as the headway fluctuation is within the proposed range, the 
test can still be considered valid, and no headway tolerance needs to 
be established.
iii. Lead Vehicle Deceleration Parameter
    The decelerating lead vehicle test scenario includes a deceleration 
parameter that dictates how quickly the lead vehicle will slow down in 
front of the subject vehicle. The agency has tentatively concluded that 
this parameter range of 0.3g to 0.4g represents real-world, manual 
application of the service brake. Previous NHTSA research had 
identified 3.0 m/s\2\ (.306g) as ``reasonably comfortable for passenger 
car occupants'' and that on average, drivers brake in such a manner 
that the vehicle decelerates at an average of 0.48g when presented with 
a unexpected obstacle.\149\ The upper limit of the lead vehicle braking 
is proposed at 0.4g to avoid a test condition in which the lead vehicle 
would provide greater brake inputs than those necessary to meet the 
minimum stopping distance requirements. NHTSA took into consideration 
the stopping distance requirements for heavy vehicles under FMVSS Nos. 
105 and 121 and the resulting average decelerations that those vehicles 
would be required to achieve. For example, an air-braked tractor 
trailer under FMVSS No. 121 would need to brake at 0.41g to meet the 
stopping distance of 310 ft from 60 mph.\150\ Given the headway 
parameters and vehicle speeds in this proposal, the agency believes a 
lead vehicle deceleration above 0.4g would create a requirement that 
could effectively reduce the minimum stopping distance requirements for 
vehicles generally.
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    \149\ Gregory M. Fitch, Myra Blanco, Justin F. Morgan, Jeanne C. 
Rice, Amy Wharton, Walter W. Wierwille, and Richard J. Hanowski 
(April 2010). Human Performance Evaluation of Light Vehicle Brake 
Assist Systems: Final Report (Report No. DOT HS 811 251) Washington, 
DC: National Highway Traffic Safety Administration, pgs. 13 and 101.
    \150\ This assumes an average deceleration that is achieved 
after an initial brake actuation time of 0.45 seconds, as this is 
the maximum actuation time allowed by FMVSS No. 121.
---------------------------------------------------------------------------

6. Manual Brake Application in the Subject Vehicle
    Each of the three lead vehicle test scenarios includes tests that 
are conducted with manual brake application in the subject vehicle. The 
process for testing with manual brake application is identical to what 
is considered a test for dynamic brake support or DBS in NHTSA's NCAP 
for light vehicles. While the term DBS is

[[Page 43215]]

not usually associated with heavy vehicles, NHTSA is including this 
requirement in this proposal to ensure that the driver's application of 
the brake pedal does not inhibit the functionality of the AEB system if 
the driver's brake application is insufficient to avoid a crash. The 
manual brake application procedure specifies that the subject vehicle's 
service brakes are applied by using a robotic brake controller to 
ensure accurate and consistent test conduct.
    A NHTSA study that examined light vehicle drivers' behavior in 
response to potential frontal crash situations found that they 
typically exhibit multi-stage braking behavior.\151\ This means that 
the drivers initially applied and held the brake moderately, and then 
continued to a full application if perceived to be necessary. A 
subsequent NHTSA study concluded that a significant portion of heavy 
vehicle operators display the same multi-stage braking behavior.\152\ 
The agency believes that in real world cases where the operator may 
apply insufficient brake force to avoid a rear-end collision, an AEB 
system should apply the necessary supplemental braking necessary to 
avoid a collision. Furthermore, by using manual brake application in 
the test scenarios, NHTSA is able to test AEB performance at higher 
test speeds.
---------------------------------------------------------------------------

    \151\ Mazzae, E., Barickman, F., Scott Baldwin, G., and 
Forkenbrock G., ``Driver Crash Avoidance Behavior with ABS in an 
Intersection Incursion Scenario on Dry Versus Wet Pavement,'' SAE 
Technical Paper 1999-01-1288, 1999, doi:10.4271/1999-01-1288.
    \152\ Every, J., Salaani, M., Barickman, F., Elsasser, D., et 
al., ``Braking Behavior of Truck Drivers in Crash Imminent 
Scenarios,'' SAE International Journal of Commercial Vehicles, 
7(2):2014, doi:10.4271/2014-01-2380.
---------------------------------------------------------------------------

    In real world cases, the brake pedal can be applied by a heavy 
vehicle operator in an infinite number of ways (varying force, reaction 
time, duration, etc.). Since the manual brake application represents an 
operator's response to an unexpected obstacle and the forward collision 
warning, the agency is proposing a brake pedal application that results 
in a mean deceleration of 0.3g. A heavy vehicle field study by NHTSA 
indicated that when presented with an FCW triggered by a valid object 
and requiring a crash avoidance maneuver, the operators braked on 
average at a maximum of 0.3g.\153\ Manually applying the brake at 0.3g 
also is a low enough value to improve the capability of observing an 
AEB automatic braking intervention that is occurring simultaneously on 
top of that. The minimum stopping distance requirements for heavy 
vehicles in existing FMVSSs require braking at around 0.4g. Thus 
hypothetically, if a heavy vehicle's service brakes were manually 
applied at a higher deceleration of 0.4g for example, and the brakes 
were only capable of a maximum of 0.4g of deceleration, AEB 
intervention would be incapable of producing additional deceleration 
and would not be observable.
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    \153\ Grove, K., Atwood, J., Hill, P., Fitch, G., Blanco, M., 
Guo, F., . . . & Richards, T. (2016, June). Field study of heavy-
vehicle crash avoidance systems. (Final report. Report No. DOT HS 
812 280). Washington, DC: National Highway Traffic Safety 
Administration.
---------------------------------------------------------------------------

    There are two methods to perform the manual brake application--
using either displacement feedback or hybrid feedback. Both methods are 
intended to be carried out by a robotic brake pedal controller in 
closed loop operation, and the method that is most suitable to the 
subject vehicle is chosen. Regardless of the method, it is necessary 
initially to determine a pedal position which, in the absence of any 
automatic braking from the AEB system, results in an average vehicle 
deceleration of 0.3g. The displacement feedback method then simply 
requires moving the brake pedal to the 0.3g position quickly, at a rate 
of 254 mm/s,\154\ and then maintaining that position. However, 
automatic braking in certain vehicles requires the pedal position to 
move further toward the floor, and can cause conflict with the 
displacement feedback method's control of pedal position, in turn 
adversely affecting test results.\155\ The hybrid feedback pedal 
control method provides a solution to this conflict. The hybrid method 
initially requires the same pedal position control, but then almost 
immediately begins to control the force on the pedal (and not the 
position) to maintain the 0.3g deceleration. If the AEB system 
thereafter requires further movement of the pedal, the brake controller 
is able to ``follow'' the pedal while still applying the appropriate 
force.\156\ NHTSA is proposing that the brake will be applied 1.0 
second after the vehicle has provided a FCW; this is based on the 
average time it takes a driver to react when presented with an 
obstacle.\157\ Although these average decelerations and reaction times 
are based on behavior of light vehicle drivers, we feel that it is 
sufficient basis to simulate a scenario in which a heavy vehicle 
operator brakes partially and insufficiently to fully avoid a rear-end 
collision.
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    \154\ Previous NHTSA research related to AEB examined pedal 
application rates by drivers in emergency and non-emergency 
situations, and determined that pedal application rate is important 
in AEB testing with manual braking, and that the appropriate 
application rate is 254 mm/s. NHTSA, August 2014. Automatic 
Emergency Braking System (AEB) Research Report, An Update of the 
June 2012 Research Report Titled, ``Forward-Looking Advanced Braking 
Technologies Research Report.'' Docket NHTSA-2012-0057-0037.
    \155\ NHTSA, August 2014. Automatic Emergency Braking System 
(AEB) Research Report, An Update of the June 2012 Research Report 
Titled, ``Forward-Looking Advanced Braking Technologies Research 
Report.'' Docket No. NHTSA-2012-0057-0037.
    \156\ Id.
    \157\ Previous NHTSA research has shown that on average, it 
takes drivers 1.04 s to begin pressing the brake when presented with 
an unexpected obstacle and 0.8 s when presented with an anticipated 
obstacle. Gregory M. Fitch, Myra Blanco, Justin F. Morgan, Jeanne C. 
Rice, Amy Wharton, Walter W. Wierwille, and Richard J. Hanowski 
(2010, April) ``Human Performance Evaluation of Light Vehicle Brake 
Assist Systems: Final Report'' (Report No. DOT HS 811 251), 
Washington, DC: National Highway Traffic Safety Administration, p. 
101.
---------------------------------------------------------------------------

B. Conditions for Vehicle Tests

    The test conditions are used to control the environmental, road 
surface, subject vehicle, and equipment conditions to ensure 
consistency both to define potential variabilities in conditions under 
which an AEB system would be expected to operate while also providing 
consistent conditions to reduce test variability due to extraneous 
factors. NHTSA recognizes that there are an unlimited number of non-
ideal environmental conditions present in the real world, and it would 
be unreasonable to attempt to reproduce most of them within practical 
constraints in the testing environment. Thus, in many cases, the 
proposed test conditions were chosen to represent near-ideal conditions 
with the goal of reducing variability in the test results. For example, 
if testing were conducted at below-freezing temperatures with snowfall, 
it would be difficult to interpret whether poor test results were due 
to the AEB system or reduced road surface friction.
    Many of the proposed conditions were selected based on research 
data and engineering practices, and reasonable deduction. In some 
cases, as appropriate, the agency considered that conditions should be 
the same or similar to what is specified in other heavy vehicle brake-
related FMVSS. This usage of pre-established conditions may help reduce 
testing burden, since fewer testing conditions would need to be 
adjusted between different FMVSS brake-related compliance tests. It 
also ensures that the minimum stopping distance requirements in the 
braking standards would be achievable during an AEB test.
    Each test procedure for the three scenarios specifies a point at 
which thereafter the test conditions described in this section apply 
and will be maintained. For the stopped lead vehicle and slower-moving 
lead vehicle

[[Page 43216]]

test scenarios, this point is at a 5 second time to collision. For the 
decelerating lead vehicle test scenario, this point is 1 second prior 
to the onset of lead vehicle deceleration.
1. Environmental Conditions
    The ambient temperature range specified in this proposal is 2 to 40 
degrees Celsius; this is the same range as specified in FMVSS No. 136, 
which avoided testing at 0 degrees Celsius because it could impact tire 
performance and in turn the variability of test results.
    The maximum wind speed is 5 m/s, which is the same as what is 
specified in FMVSS No. 136. This value was chosen to reduce the 
potential lateral displacement of certain heavy vehicles.
    NHTSA considered that certain environmental conditions should be 
near-ideal to prevent sensor performance degradation and maintain 
repeatability of vehicle testing. First, ambient illumination would be 
at or above 2,000 lux. This represents daytime illumination that is at 
a minimum equivalent to an overcast day.\158\ A NHTSA study has shown 
that darkness can cause degradation of sensor performance.\159\ NHTSA 
analysis shows that 87 percent of heavy vehicle rear-end crashes occur 
during daylight conditions.\160\ Therefore, NHTSA tentatively concludes 
that daylight testing is necessary to ensure that AEB systems address 
the rear-end crash safety problem.
---------------------------------------------------------------------------

    \158\ During an overcast day (no sun), when the solar altitude 
is around 6 degrees, the light intensity on a horizontal surface is 
around 2,000 lux. Illuminating Engineering Society of North America. 
1979. ``Recommended Practice of Daylighting.''
    \159\ NHTSA, August 2014. ``Automatic Emergency Braking System 
(AEB) Research Report--An Update of the June 2012 Research Report 
Titled, `Forward-Looking Advanced Braking Technologies Research 
Report.' '' Docket NHTSA-2012-0057-0037.
    \160\ Data are from 2017-2019 FARS and CRSS crash databases, as 
discussed in the PRIA section on initial AEB target population.
---------------------------------------------------------------------------

    Second, during testing, the sun would not be below 15 degrees of 
elevation and within 25 degrees laterally from the center plane of the 
subject vehicle. This specification reduces the likelihood of glare or 
washout for camera-based sensors that could lead to degradation of 
sensor and AEB system performance.\161\
---------------------------------------------------------------------------

    \161\ NHTSA, August 2014. ``Automatic Emergency Braking System 
(AEB) Research Report--An Update of the June 2012 Research Report 
Titled, `Forward-Looking Advanced Braking Technologies Research 
Report.' '' Docket NHTSA-2012-0057-0037.
---------------------------------------------------------------------------

    Visibility also would not be affected by fog, smoke, ash or other 
particulate, as recommended in previous agency research findings.\162\ 
This improves test repeatability and also aligns with many real-world, 
rear-end crash conditions. A review of NHTSA's crash data indicates 
that 81 percent of those occur when the weather conditions are clear or 
cloudy and with no precipitation.\163\
---------------------------------------------------------------------------

    \162\ NHTSA, August 2014. ``Automatic Emergency Braking System 
(AEB) Research Report--An Update of the June 2012 Research Report 
Titled, `Forward-Looking Advanced Braking Technologies Research 
Report.' '' Docket NHTSA-2012-0057-0037.
    \163\ This is also supported by another study (Grove, Atwood, 
Fitch and Blanco, M, 2016, ``Field Study of Heavy-Vehicle Crash 
Avoidance Systems'') which concluded that over 88 percent of heavy 
vehicle crashes occurred when the conditions were, clear, partly 
cloudy, or overcast.
---------------------------------------------------------------------------

2. Road Surface Conditions
    The road surface upon which vehicle tests will be conducted must 
also be in a defined condition to help achieve repeatable testing. The 
proposed conditions specify that the road surface is free of debris, 
irregularities, or undulations, such as loose pavement, large cracks, 
or dips. These could affect the vehicle's ability to brake properly or 
maintain its heading, and ultimately reduce the repeatability of a 
test. The test surface is also required to be level, with a slope 
between 0 and 1 degrees, because the slope of a road surface can affect 
the performance of an AEB-equipped vehicle.\164\ A surface that slopes 
up and down could obstruct a sensor's view of an object ahead. It could 
also influence the dynamics and layout involved in the proposed AEB 
test scenarios, as travelling up or down a slope makes braking to a 
stop more or less difficult. In order to have predictable tire 
adherence under braking, the surface must also be dry and have a 
controlled coefficient of friction. NHTSA is proposing that the test 
track surface have a peak friction coefficient of 1.02 when measured in 
accordance with ASTM International (ASTM) E1337 \165\ using an ASTM 
F2493 standard reference test tire and without water delivery.\166\ 
Surface friction is a critical factor in brake system performance 
testing, including AEB, since it correlates with tire grip and the 
achievable stopping distance. The presence of moisture will 
significantly change the measured performance of a braking system. A 
dry surface is more consistent and provides for greater test 
repeatability. Also, the proposed peak friction coefficient is the same 
value that NHTSA uses for brake performance testing.
---------------------------------------------------------------------------

    \164\ Kim, H. et al., ``Autonomous Emergency Braking Considering 
Road Slope and Friction Coefficient,'' International Journal of 
Automotive Technology, 19, 1013-1022 (2018).
    \165\ ASTM International, ASTM E1337, ``Standard Test Method for 
Determining Longitudinal Peak Braking Coefficient (PBC) of Paved 
Surfaces Using Standard Reference Test Tire.''
    \166\ See 87 FR 34800 (June 8, 2022), Final Rule, Federal Motor 
Vehicle Safety Standards, Consumer Information; Standard Reference 
Test Tire.
---------------------------------------------------------------------------

    This proposal specifies up to two straight lines be marked on the 
test surface to simulate lane markings. In order to provide flexibility 
for different road configurations at a variety of test track 
facilities, lane markings may or may not be present during testing. If 
present, the lines would be of any color or configuration (e.g., solid, 
dashed, double-line, etc.). If two lines are used, they would be 
parallel to each other and between 2.7 to 4.5 m apart, which is 
representative of typical lane widths.
    Lastly, the environment would not contain obstructions that could 
interfere with detection of a lead vehicle or other test equipment 
ahead and have an unintentional effect on the field of view of the AEB 
system, in turn compromising test repeatability. Thus, the subject 
vehicle during testing would not travel beneath overhead structures 
such as signs, bridges, or gantries, and each compliance test would be 
conducted without any vehicles, obstructions, or stationary objects 
within one lane width of either side of the subject vehicle path unless 
called for in the test procedure.
3. Subject Vehicle Conditions
    Many of the subject vehicle conditions exist to ensure that a 
vehicle chosen for testing is in a working condition that represents 
the vehicle as it is sold into the market, and capable of performing as 
intended by the manufacturer. Thus, the vehicle conditions specify that 
no AEB malfunction telltale is active, vehicle components ahead of AEB 
sensors are clean and do not obstruct the sensors, the original tires 
are installed and properly inflated, and non-consumable fluids (e.g., 
brake fluid, engine coolant, etc.) are full.
    Other conditions exist to ensure that vehicle performance is 
comparable to that found in the real world. Prior to testing, the 
vehicle's service brakes are burnished according to the burnishing 
procedures already used in FMVSS No. 121 or 105 testing, as appropriate 
for the vehicle prior to the beginning of testing. Burnishing helps to 
gradually seat and condition new brake components, particularly the 
brake pads and rotors/drums, which come into contact and provide 
friction under braking. Burnishing helps achieve optimal and repeatable 
brake performance. If burnishing was done previously, for example due 
to the running of compliance tests for other FMVSS, it would not be 
repeated.
    The agency also proposes that the brake temperatures be between 66 
and

[[Page 43217]]

204 degrees Celsius prior to the beginning of a test, which is the same 
as specified in FMVSS No. 136. In the agency's experience, this initial 
temperature range allows the brakes to perform well without being under 
or over heated during testing, and the upper end of 204 degree Celsius 
does not require unreasonably long cool-down time between test runs.
    The agency has also considered that vehicles may have adjustable 
characteristics or configurable systems that a vehicle operator may 
choose to adjust, and some of these are factors that could affect the 
outcome of an AEB test. Since each vehicle operator could potentially 
choose different settings for these systems, the testing would ensure 
that AEB systems are capable of meeting the test requirements 
regardless of which choices were made. Accordingly, this proposal 
specifies that these adjustable factors will be nearly in any 
configurable level during testing. Consumable fluids (e.g., fuel, 
diesel exhaust fluid, etc.) and propulsion battery charge will be 
between 5-100 percent of their capacity. Cruise control systems would 
be tested in any available setting, including adaptive cruise control 
modes. In the event that adaptive cruise control is engaged and remains 
engaged during the event, the FCW would not be required. This is 
because an adaptive cruise control system is intended to slow the 
vehicle to avoid a collision prior to a collision being imminent and 
without notification to the driver.\167\
---------------------------------------------------------------------------

    \167\ Adaptive cruise control is a driver assistance technology 
that automatically adjusts vehicle speed to maintain a certain 
distance from a vehicle ahead.
---------------------------------------------------------------------------

    Forward collision warnings would be tested in any configurable 
setting. If the vehicle is equipped with an engine-braking system, 
tests would be conducted with the system either engaged or disengaged. 
The controls for the headlamps and regenerative braking would be tested 
in any available position.
    Regarding the weight of the subject vehicle during testing, this 
proposal specifies that the vehicle is loaded to its gross vehicle 
weight rating. Truck tractors will be loaded to its GVWR by connecting 
a control trailer. The specifications for this control trailer, which 
is an unbraked, single-axle flatbed, are equivalent to those found in 
FMVSS No. 136. The agency believes it is important to test the 
performance of AEB systems when the vehicle is at its heaviest 
allowable condition, because heavy vehicles often travel in a fully 
loaded condition and it generally presents the most challenging 
scenario for braking (i.e., stopping a heavier vehicle is more 
difficult). This loading condition is identical to the loaded condition 
specified for FMVSS stopping distance assessment. This may improve 
testing efficiency for NHTSA by having fewer loading conditions 
specified among FMVSS.
    Finally, because a vehicle will be tested at its GVWR, this 
proposal specifies that, if a vehicle is equipped with a liftable axle, 
it will be placed in the down position during testing.

C. Proposed Requirements for False Activation

1. No Automatic Braking Requirement
    NHTSA proposes a requirement that the subject vehicle, when 
presented with two false activation test scenarios, must not 
automatically apply braking that results in a peak deceleration of more 
than 0.25g when manual braking is not applied, nor a peak deceleration 
of more than 0.45g when manual braking is applied. False activation 
refers to cases where the AEB systems automatically activates the 
service brakes although there is no object present in the path of the 
vehicle with which it would collide. The associated vehicle tests are 
run both with and without manual braking. During test runs without 
manual braking, the AEB system must not initiate braking that results 
in a peak deceleration of more than 0.25g. A 0.25g deceleration is 
below the 0.3g threshold described earlier as a comfortable 
deceleration which has a low probability of creating safety concerns 
such as rear-end crashes (if the subject vehicle would brake too 
hard).\168\ Also, 0.25g is an easily measurable deceleration when 
testing.
---------------------------------------------------------------------------

    \168\ Gregory M. Fitch, Myra Blanco, Justin F. Morgan, Jeanne C. 
Rice, Amy Wharton, Walter W. Wierwille, and Richard J. Hanowski 
(2010, April) Human Performance Evaluation of Light Vehicle Brake 
Assist Systems: Final Report (Report No. DOT HS 811 251) Washington, 
DC: National Highway Traffic Safety Administration, p. 13.
---------------------------------------------------------------------------

    During test runs when manual braking is being applied, the AEB 
system must not initiate braking that results in a peak deceleration of 
more than 0.45g. When testing using manual braking, the goal is to have 
a manual braking deceleration of 0.3g, and so the AEB system must not 
cause more than approximately 0.15g of additional deceleration. This 
0.15g amount is less than the 0.25g of peak deceleration permitted in 
tests without manual braking--however, allowing the same 0.25g above 
manual braking would mean that up to a total peak deceleration of 0.55g 
would be permitted. Because 0.55g could exceed the maximum deceleration 
capacity of certain heavy vehicles, it would, in turn, render the test 
impossible to fail for those vehicles. Therefore, the lower threshold 
of additional deceleration is proposed for false activation tests with 
manual braking.
2. Vehicle Test Scenarios
    Under this proposal, the false activation requirement would be 
evaluated by executing two vehicle test scenarios--a steel trench plate 
test and a pass-through test. The steel trench plate test was chosen 
because in previous agency testing that included eight different false 
activation test scenarios, the steel trench plate scenario was the only 
one that produced false activation of the AEB system.\169\ The pass-
through test is similar to the United Nations Economic Commission for 
Europe (UNECE) Regulation 131 pass-through test.\170\
---------------------------------------------------------------------------

    \169\ Snyder, A., Martin, J., & Forkenbrock, G. (2013, July). 
``Evaluation of CIB system susceptibility to non-threatening driving 
scenarios on the test track.'' (Report No. DOT HS 811 795). 
Washington, DC: National Highway Traffic Safety Administration.
    \170\ UNECE Regulation 131, ``Uniform provisions concerning the 
approval of motor vehicles with regard to the Advanced Emergency 
Braking Systems (AEBS),'' see 6.8 False reaction test, U.N. 
Regulation No. 131 (Feb. 27, 2020), available at https://unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2015/R131r1e.pdf.
---------------------------------------------------------------------------

    The proposed false activation tests establish only a baseline for 
system functionality. For practical reasons they are not comprehensive, 
nor sufficient to eliminate susceptibility to false activations in the 
myriad of circumstances in the real world. However, the proposed tests 
are a practicable means to establish a minimum threshold of 
performance. The agency expects that vehicle manufacturers will design 
AEB systems to thoroughly address the potential for false 
activations.\171\ Manufacturers have a strong market incentive to 
mitigate false positives and have been successful even in the absence 
of specific requirements.
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    \171\ From NHTSA's NCAP Request for Comments notice regarding 
AEB: ``Specifically, the Alliance stated that vehicle manufacturers 
will optimize their systems to minimize false positive activations 
for consumer acceptance purposes, and thus such tests will not be 
necessary. Similarly, Honda stated that vehicle manufacturers must 
already account for false positives when considering marketability 
and HMI.'' 87 FR 13452 at 13460.
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i. Steel Trench Plate
    This test recreates a roadway scenario where the subject vehicles 
encounter a steel trench plate which is placed on the road surface 
ahead in the same lane. The subject vehicle is driven at 80 km/h toward 
the steel trench plate at a constant speed.

[[Page 43218]]

    The tests would be conducted either with or without manual brake 
application. Manual braking is included in these scenarios to ensure 
that even when a vehicle's service brake is actuated, false activation 
would not occur. For tests without manual braking, the accelerator is 
only released if a forward collision warning is issued. For test with 
manual braking, the accelerator is released at either the forward 
collision warning or 1 second prior to the manual braking, whichever 
occurs first. Manual braking begins when the subject vehicle is 1.1 
seconds away from the steel trench plate. The test ends when the 
subject vehicle either comes to a stop prior to crossing over the 
leading edge of the steel trench plate, or it proceeds to drive over 
the steel trench plate. Figure 8 shows the basic setup for the steel 
trench plate scenario.
[GRAPHIC] [TIFF OMITTED] TP06JY23.008

    Unlike the test scenarios in which the subject vehicle approaches a 
lead vehicle, the agency proposes that the false activation tests be 
run at a single speed rather than over a range of speeds. False 
activations occurring at interstate speeds would create the most severe 
unintended consequences of AEB braking. Therefore, the proposal 
includes only a test at a single speed of 80 km/h.
ii. Pass-Through
    This test recreates a roadway scenario where the subject vehicle 
must travel between two parked cars that are adjacent to the left and 
right sides of the subject vehicle's travel lane. The parked cars are 
represented by two vehicle test devices. The lateral distance between 
the parked cars is 4.5 m, which is sufficient to give the subject 
vehicle enough space to pass between them and yet be close enough to be 
in the field of view of AEB sensors. The subject vehicle is driven 
along the center of the travel lane and toward the gap between the 
parked cars at a speed of 80 km/h. For tests without manual braking, 
the accelerator is only released if a forward collision warning is 
issued. For tests with manual braking, the accelerator is released at 
either the forward collision warning or 1 second prior to the manual 
braking, whichever occurs first; manual braking begins when the front 
plane of the subject vehicle is 1.1 seconds away from the rear plane of 
the two parked cars).
[GRAPHIC] [TIFF OMITTED] TP06JY23.009

D. Conditions for False Activation Tests

    The false activation requirement is conducted under a set test 
conditions identical to those used for AEB tests. However, there are 
equipment conditions which apply specifically to these false activation 
tests.
    The equipment conditions that apply to the two false positive 
scenarios in this proposal relate to the steel trench plate and the 
vehicles used for the pass-through test. The steel trench plate is a 
piece of equipment that represents a steel plate typically used to 
cover excavation holes or irregularities in the road surface during 
construction work, and which is meant to be driven over by

[[Page 43219]]

vehicles. The steel trench plate specified in this proposal is made of 
ASTM A36 steel, a common structural steel alloy, and has the dimensions 
2.4 m x 3.7 m x 25 mm. Any metallic fasteners used to secure the steel 
trench plate are flush with the top surface of the plate, to avoid 
effectively increasing the profile height and radar cross-section of 
the plate. The two vehicles used for the pass-through test are vehicle 
test devices identical to those that would be used in the lead vehicle 
testing.

E. Potential Alternatives to False Activation Tests

    As alternatives to these two false activation tests, NHTSA is 
considering requiring a robust documentation process, or specifying a 
data storage requirement. NHTSA is considering requiring this 
documentation and data in addition to or in place of the proposed false 
activation tests. First, NHTSA seeks comment on the anticipated impacts 
on safety and the certification burden if the agency were to finalize a 
rule that did not contain one or both of the proposed false positive 
tests.
    The agency is considering requiring that manufacturers maintain 
documentation demonstrating that process standards were followed 
specific to the consideration of false application of automatic 
braking. Other industries where safety-critical software-controlled 
equipment failures may be life threatening (e.g., aviation,\172\ 
medical devices \173\) are regulated in some respects via process 
controls ensuring that software development engineering best practices 
are followed. This approach recognizes that system tests are limited in 
their ability to evaluate complex, and constantly changing software 
driven control systems.
---------------------------------------------------------------------------

    \172\ 14 CFR 33.201(a) The engine must be designed using a 
design quality process acceptable to the Federal Aviation 
Administration, that ensures the design features of the engine 
minimize the occurrence of failures, malfunctions, defects, and 
maintenance errors that could result in an in-flight shutdown, loss 
of thrust control, or other power loss.
    \173\ 21 CFR 920.30(a)(1) Each manufacturer of any class III or 
class II device, and the class I devices listed in paragraph (a)(2) 
of this section, shall establish and maintain procedures to control 
the design of the device in order to ensure that specified design 
requirements are met.
---------------------------------------------------------------------------

    Software development lifecycle practices that include risk 
management, configuration management, and quality systems are used in 
various safety-critical industries. ISO 26262 Road vehicles--Functional 
safety and related standards are examples of methods for overseeing 
software development practices. The agency is considering that a 
process standards approach could be a viable and practical way of 
regulating the risk of false positives, as false activation of braking 
is a complex engineering problem with multiple factors and conditions 
that must be considered in the real world. The agency seeks public 
comment on all aspects of requiring that manufacturers document that 
they have followed process standards in the consideration of the real-
world false activation performance of the AEB system.
    Finally, the agency considered requiring targeted data recording 
and storage of significant AEB activations. These data could then be 
used by manufacturers to improve system performance, or by the agency 
to review if a particular alleged false activation is part of a safety 
defect investigation. The agency is considering requiring that an AEB 
event that results in a speed reduction of greater than 20 km/h should 
activate the recording and storage of the following key information: 
date, time, engine hours (the time as measured in hours and minutes 
during which an engine is operated), AEB activation speed, AEB exit 
speed (vehicle speed at which the automatic braking is completely 
released), AEB exit reason (e.g. driver override with throttle, or 
brake, or system decision), location, and camera image data. This 
information could be used by investigators to analyze the source of the 
activation and determine if an activation was falsely applied. Such 
data would need to be accessible by the agency and potentially the 
vehicle operator for a full and transparent analysis. The agency seeks 
comment on all aspects of this data collection approach as an 
alternative to false positive testing, including whether this list of 
potential elements is incomplete, overinclusive, or impractical.

F. Proposed Requirements for Malfunction Indication

    NHTSA is proposing that AEB systems must continuously detect system 
malfunctions. If an AEB system detects a malfunction that prevents it 
from performing its required safety function, the vehicle would be 
required to provide the vehicle operator with a warning. The warning 
would be required to remain active as long as the malfunction exists 
while the vehicle's starting system is on. NHTSA would consider a 
malfunction to include any condition in which the AEB system fails to 
meet the proposed performance requirements. NHTSA is proposing that the 
driver must be warned in all instances of component or system failures, 
sensor obstructions, environmental limitations (like heavy 
precipitation), or other situations that would prevent a vehicle from 
meeting the proposed AEB performance requirements. While NHTSA is not 
proposing the specifics of the telltale, NHTSA anticipates that the 
characteristics of the alert will be documented in the vehicle owner's 
manual and provide sufficient information to the vehicle operator to 
identify it as an AEB malfunction.
    NHTSA considered proposing requirements pertaining to specific 
failures and including an accompanying test procedure. For instance, 
the agency could develop or use available tests that specify 
disconnecting sensor wires, removing fuses, or covering sensors to 
simulate field malfunctions. Such requirements are not included in the 
proposed regulatory text, but NHTSA is interested in comments on this 
issue.
    NHTSA also considered proposing minimum requirements for the 
malfunction telltale, to standardize ways of communicating to the 
vehicle operator. NHTSA understands that some malfunctions of the AEB 
system require repair (loose wires, broken sensors, etc.) while other 
malfunctions are temporary and will correct themselves over time (ice 
buildup on a camera). The agency considered requiring that the 
malfunction telltale convey the actions that a driver should take when 
a malfunction is detected. Such requirements are not included in the 
proposed regulatory text, but NHTSA is interested in comments on this 
issue. NHTSA seeks comment, including cost and benefit data, on the 
potential advantages of specifying test procedures that would describe 
how the agency would test a malfunction telltale and on the level of 
detail that this regulation should require of a malfunction telltale. 
Additionally, the agency considered requiring more details for the 
telltale itself, such as a standardized appearance (color, size, shape, 
illuminance). The agency seeks comment on the need and potential safety 
benefits of requiring a standardized appearance of the malfunction 
telltale and what standardized characteristics would achieve the best 
safety outcomes.

G. Deactivation Switch

    The proposed regulatory text does not permit vehicle manufacturers 
to install a manual deactivation switch that would enable the vehicle 
operator to switch off the AEB. The text is silent regarding the 
permissibility of a switch but, under the framework of the FMVSS

[[Page 43220]]

and NHTSA's interpretations of the standards, a deactivation switch 
would be prohibited if it would allow an AEB system to be deactivated 
in any circumstance in which the standard requires an AEB system to 
function. This is consistent with other FMVSS, such as FMVSS No. 108, 
``Lamps, reflective devices, and associated equipment,'' which is 
silent about a switch deactivating the stop lamps but where NHTSA has 
interpreted the standard as prohibiting such a switch.\174\ Standards 
in which a deactivation switch is permitted expressly permit the switch 
in the regulatory text, for example, FMVSS No. 126, ``Electronic 
stability control systems for light vehicles,'' where the standard 
specifically permits and regulates the performance of a deactivation 
switch,\175\ and FMVSS No. 208, ``Occupant crash protection,'' where 
the standard permitted an on-off switch for the air bag for the front 
passenger seat on particular vehicles.\176\
---------------------------------------------------------------------------

    \174\ https://isearch.nhtsa.gov/files/23833.ztv.html (last 
accessed August 31, 2022).
    \175\ FMVSS No. 126, ``ESC systems for light vehicles,'' S5.4: 
The manufacturer may include an ``ESC Off'' control whose only 
purpose is to place the ESC system in a mode or modes in which it 
will no longer satisfy the performance requirements of S5.2.1, 
S5.2.2, and S5.2.3.
    \176\ FMVSS No. 208, ``Occupant crash protection.'' FMVSS No. 
208 was written such that it permited such switches only on vehicles 
configured with no back seat or a back seat too small to accommodate 
a rear-facing child restraint system. This was an interim step to 
allow advanced air bag technology to mature and be fully 
implemented.
---------------------------------------------------------------------------

    NHTSA and FMCSA realize a switch or other method that could 
deactivate a vehicle's AEB system could be useful in some 
circumstances. There might be some heavy vehicle design or aftermarket 
equipment installations where the configuration of the vehicle could 
potentially interfere with the AEB sensing system. For example, a 
snowplow might be attached in a manner that obstructs an AEB sensor. 
Some vehicles may have uses where an AEB system may be incompatible 
with its operating environment, for example, logging operations or 
other on/off road environments.
    Special conditions could be addressed by drafting the standard to 
allow manual deactivation under limited circumstances when the system 
is compromised. However, an FMVSS in which deactivation of the system 
is easily accomplished would likely reduce the safety benefit of the 
proposed rule. NHTSA seeks comments on the merits of and need for 
manual deactivations of AEB systems. If the standard were to permit a 
deactivation mechanism of some sort, how could NHTSA allow for 
deactivations while ensuring the mechanism would not be abused or 
misused by users? Alternatively, NHTSA is interested in comments on the 
approach of the standard's restricting the automatic deactivation of 
the AEB system generally but providing for special conditions in which 
the vehicle is permitted to automatically deactivate or otherwise 
restrict braking authority given to the AEB system.
    NHTSA seeks comment on the merits of various performance 
requirements related to manual deactivation switches for AEB systems. 
The agency seeks comment on the appropriate performance requirements if 
the agency were to permit the installation of a manually operated 
deactivation switch. Such requirements might include limitations such 
that the default position of the switch be ``AEB ON'' with each cycle 
of the starting system or that the deactivation functionality be 
limited to specific speeds.

H. System Documentation

    NHTSA seeks comment on alternate regulatory approaches that might 
be appropriate for regulating complex systems that depend heavily on 
software performance. FMVSS have historically included requirements 
that can be inspected or tested by the agency to verify compliance. In 
some cases, such as in FMVSS No. 126, the agency has required 
manufacturers to maintain technical documentation available for agency 
review upon request to ensure that electronic stability control systems 
were designed to mitigate vehicle understeer (49 CFR 571.126 S5.6). The 
agency established this requirement in the absence of suitable test 
procedures for evaluating understeer.
    In the case of AEB, there are similar limits to testing systems in 
controlled environments. AEB systems operating on roadways will be 
subject to many scenes and stimuli that are not present on a test 
track--e.g., precipitation, lighting, roadway curvature and elevation 
changes, signage, other road users, animals, debris, etc.--and these 
scenes and stimuli could potentially influence real world effectiveness 
of AEB systems. The agency seeks comment on documentation requirements 
that may be effective in encouraging real world effectiveness (e.g., 
maximizing true positive rate and minimizing false positive rate) and 
in ensuring that AEB systems are developed and maintained in a manner 
that minimizes performance risks.
    The agency is considering requirements for manufacturers to 
document a risk-based design approach identifying and mitigating 
reasonably foreseeable risks alongside configuration management records 
of all software/hardware updates performed by the manufacturer. 
Manufacturers would also need to disclose certain servicing and system 
limitation requirements and make AEB-related data stored in vehicles 
available. Examples of requirements under consideration include:
     Manufacturers must establish and maintain procedures that 
provide a risk-based approach in designing, implementing, and (if 
applicable) updating each system required under this standard. 
Manufacturers must maintain documentation over the system lifetime 
detailing the outcome of the risk-based approach taken to ensure the 
safety of such systems.
     Where servicing is required to maintain system 
performance, each manufacturer must establish and maintain instructions 
and procedures for performing and verifying that the servicing meets 
the specified requirements.
     Certain information must be disclosed to consumers at the 
time of first sale in a single document such as an owner's manual:
    [cir] If servicing requirements include periodic maintenance, the 
maintenance schedule must be identified.
    [cir] Manufacturers must include a statement describing the 
limitations of AEB and explaining that AEB is an emergency system that 
does not replace the need for normal actuation of the service brakes.
     Each manufacturer must maintain documentation that 
captures the full system configuration, including all hardware, 
software, and firmware, for each vehicle at the time of first sale and 
at the time of any update to the system configuration by the 
manufacturer.
     Each AEB system or a system that communicates with the AEB 
system must store information logging at least the last three AEB 
activation events or all AEB activation events occurring within the 
past three drive cycles.
     The vehicle must store the status of the AEB system 
(active, inactive, disabled, warning, engaged, disengaged, 
malfunctioning, etc.).
    NHTSA believes that manufacturers that have installed AEB systems 
in their fleet may already be meeting many of the documentation 
requirements above. The agency seeks comment on the suitability of 
these requirements and on any changes that manufacturers would have to 
introduce in their internal processes and consumer-facing documentation 
(e.g., owner's manuals). NHTSA is interested in learning

[[Page 43221]]

whether manufacturers find discrepancies between real-world performance 
and data collected on test tracks with surrogate vehicles.

I. ESC Performance Test

    This proposal would require nearly all heavy vehicles to have an 
ESC system that meets the equipment requirements, general system 
operational capability requirements, and malfunction detection 
requirements of FMVSS No. 136. However, this proposal would not require 
vehicles not currently required to have ESC systems to meet any test 
track performance requirements for ESC systems because NHTSA is 
conscious of the potential testing burden on small businesses and the 
multi-stage vehicle manufacturers involved in class 3 through 6 vehicle 
production. NHTSA requests comments on whether the agency should 
establish performance requirements for ESC for all vehicles covered by 
this proposal. If ESC performance requirements would be appropriate, 
NHTSA seeks comment on which regulatory tests and requirements would be 
appropriate for the class 3-8 vehicles which this notice proposes to 
make applicable to FMVSS No. 136. NHTSA also seeks comment on whether 
manufacturers of these vehicles should have the option to certify to 
FMVSS No. 126 or FMVSS No. 136, whether a new ESC test procedure should 
be developed for some or all of these vehicles, or whether NHTSA should 
give the manufacturer the option to choose the ESC standard to which to 
certify.
    NHTSA conducted some limited ESC testing for class 3-6 vehicles, as 
part of research efforts during the development of FMVSS No. 136, which 
was established in 2015, and as part of its recent AEB testing.\177\ 
The ESC testing performed has however been sufficient to indicate that 
the test procedures currently established in FMVSS Nos. 126 and 136 
would require modification in order to better suit class 3 through 6 
vehicles. For example, the vehicle test speeds specified in FMVSS No. 
136, which are designed to induce ESC activation in class 7 and 8 
trucks and buses at speeds under 48 km/h (30 mph), did not induce ESC 
activation in the vehicles that were tested. This testing indicates 
that the maximum test speeds and speed reduction requirements would 
likely need to be modified.
---------------------------------------------------------------------------

    \177\ This information is available in ``ESC Track Test Data for 
Class 3-6 Vehicles,'' which has been placed in the docket identified 
in the heading of this NPRM.
---------------------------------------------------------------------------

J. Severability

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

VIII. Vehicle Test Device

    NHTSA has proposed the same vehicle test device described below for 
use in the proposed requirements for AEB for light vehicles. An 
identical discussion of the vehicle test device appears in the NPRM 
proposing the FMVSS for light vehicles.

A. Description and Development

    To ensure repeatable and reproducible testing that reflects how a 
subject vehicle would be expected to respond to an actual vehicle in 
the real world, this proposal includes broad specifications for a 
vehicle test device to be used as a lead vehicle or pass through 
vehicle during testing. NHTSA is proposing that the vehicle test device 
be based on certain specifications defined in ISO 19206-3:2021, ``Road 
vehicles--Test devices for target vehicles, vulnerable road users and 
other objects, for assessment of active safety functions--Part 3: 
Requirements for passenger vehicle 3D targets.'' \178\ The vehicle test 
device is a tool that NHTSA proposes to use to facilitate the agency's 
compliance tests to measure the performance of AEB systems required by 
the proposed FMVSS. This NPRM describes the vehicle test device that 
NHTSA would use.
---------------------------------------------------------------------------

    \178\ https://www.iso.org/standard/70133.html. May 2021.
---------------------------------------------------------------------------

    The surrogate vehicle NHTSA currently uses in its research testing 
is the Global Vehicle Target (GVT). The GVT is a full-sized, harmonized 
surrogate vehicle developed to test crash avoidance systems while 
addressing the limitations of earlier generation surrogate vehicles. To 
obtain input from the public and from industry stakeholders, NHTSA 
participated in a series of five public workshops and three radar 
tuning meetings between August 2015 and December 2016. These workshops 
and meetings provided representatives from the automotive industry with 
an opportunity to inspect, measure, and assess the realism of prototype 
surrogates during the various stages of development. Workshop and 
meeting participants were permitted to take measurements and collect 
data with their own test equipment, which they could then use to 
provide specific recommendations about how the surrogate vehicle's 
appearance, to any sensor, could be improved to increase realism.
    After feedback from automotive vehicle manufacturers and suppliers 
was incorporated into an earlier design of the GVT, a series of high-
resolution radar scans were performed by the Michigan Tech Research 
Institute (MTRI) under NHTSA contract. These measurements provided an 
independent assessment of how the radar characteristics of the GVT 
compared to those from four real passenger cars.\179\ This study found 
that the GVT has generally less radar scatter than the real vehicles to 
which it was compared. However, MTRI found that ``even though the [GVT] 
may more often reflect a greater amount of energy than the [real] 
vehicles, it is not exceeding the maximum energy of the returns from 
the vehicles. Thus, a sensor intended for the purpose of detecting 
vehicles should perform well with the [GVT].'' \180\
---------------------------------------------------------------------------

    \179\ The comparison passenger cars used were a 2008 Hyundai 
Accent, a 2004 Toyota Camry, a 2016 Ford Fiesta hatchback, and a 
2013 Subaru Impreza.
    \180\ Buller, W., Hart, B., Aden, S., and Wilson, B. (2017, May) 
``Comparison of RADAR Returns from Vehicles and Guided Soft Target 
(GST),'' Michigan Technological University, Michigan Tech Research 
Institute. Docket NHTSA-2015-0002-0007.
---------------------------------------------------------------------------

    NHTSA also performed tests to determine the practicality of using 
the GVT for test-track performance evaluations by examining how 
difficult it was to reassemble the GVT after it was struck in a test. 
Using a randomized matrix designed to minimize the effect of learning, 
these tests were performed with teams of three or five members familiar 
with the GVT reassembly process. NHTSA found that reassembly of the GVT 
on the robotic platform takes approximately 10 minutes to complete; 
however, additional time is often required to re-initialize the robotic 
platform GPS afterwards.\181\
---------------------------------------------------------------------------

    \181\ Snyder, Andrew C. et al., ``A Test Track Comparison of the 
Global Vehicle Target (GVT) and NHTSA's Strikeable Surrogate Vehicle 
(SSV),'' July 2019. https://rosap.ntl.bts.gov/view/dot/41936.
---------------------------------------------------------------------------

    Finally, NHTSA conducted its own crash imminent braking tests to 
compare the speed reduction achieved by three passenger cars as they 
approached the GVT, compared to the Strikable Surrogate Vehicle (SSV), 
the surrogate vehicle NHTSA currently uses for its NCAP AEB tests. 
These tests found that any differences that might exist between the GVT 
and the SSV were small enough to not appreciably influence the outcome 
of vehicle testing.\182\
---------------------------------------------------------------------------

    \182\ Id.
---------------------------------------------------------------------------

    When used during AEB testing, the GVT is secured to the top of a 
low-

[[Page 43222]]

profile robotic platform. The robotic platform is essentially flat and 
is movable and programmable. The vehicle test device's movement can be 
accurately and repeatably defined and choreographed with the subject 
vehicle and testing lane through the use of data from the robotic 
platform's on-board inertial measurement unit, GPS, and closed-loop 
control facilitated by communication with the subject vehicle's 
instrumentation. The shallow design of the robotic platform allows the 
test vehicle to drive over it. The GVT is secured to the top of the 
robotic platform using hook-and-loop fastener attachment points, which 
allow the pieces of the GVT to easily and safely break away without 
significant harm to the vehicle being tested if struck.
    The internal frame of the GVT is constructed primarily of vinyl-
covered foam segments held together with hook-and-loop fasteners. The 
GVT's exterior is comprised of multiple vinyl ``skin'' sections 
designed to provide the dimensional, optical, and radar characteristics 
of a real vehicle that can be recognized as such by camera and radar 
sensors.\183\ If the subject vehicle impacts the GVT at low speed, the 
GVT is typically pushed off and away from the robotic platform without 
breaking apart. At higher impact speeds, the GVT breaks apart as the 
subject vehicle essentially drives through it.
---------------------------------------------------------------------------

    \183\ ``A Test Track Comparison of the Global Vehicle Target 
(GVT) and NHTSA's Strikeable Surrogate Vehicle,'' DOT HS 812-698.
---------------------------------------------------------------------------

B. Specifications

    The most recent, widely-accepted iteration of vehicle test device 
specifications is contained in ISO 19206-3:2021.\184\ Using data 
collected by measuring the fixed-angle/variable-range radar cross 
section for several real vehicles, ISO developed generic 
``acceptability corridors,'' which are essentially boundaries that the 
vehicle test device's radar cross section must fit within to be deemed 
representative of a real vehicle.\185\ All vehicles that ISO tested 
have radar cross section measurements that fit within the boundaries 
set forth in the ISO standard.
---------------------------------------------------------------------------

    \184\ 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.
    \185\ The vehicles tested to develop the ISO standard are: 2016 
BMW M235i, 2006 Acura RL, 2019 Tesla Model 3, 2017 Nissan Versa, 
2018 Toyota Corolla, 2019 Ford Fiesta.
---------------------------------------------------------------------------

    This proposal would incorporate by reference ISO 19206-3:2021 into 
NHTSA's regulations and specify that the vehicle test device meets 
several specifications in ISO 19206-3:2021, in addition to other 
specifications identified by NHTSA. Because the GVT was considered 
during the development of ISO 19206-3:2021, the GVT would meet the 
standard's specifications. However, should the design of the GVT change 
or a new vehicle test device be developed, reference to the more 
general specifications of ISO 19206-3:2021 should ensure that NHTSA is 
able to test with such other vehicle test devices and should also 
ensure that such vehicle test devices have properties needed by an AEB 
system to identify it as a motor vehicle.
    The vehicle test device's physical dimensions are proposed to be 
consistent with those of the subcompact and compact car vehicle class. 
The specific range of dimensions in this proposal for individual 
surfaces of the vehicle test device are incorporated from ISO 19206-
3:2021, Annex A, Table A.4. These include specifications for the test 
device's width and the placement of the license plate, lights, and 
reflectors relative to the rear end of the vehicle test device.
    The vehicle test device is proposed to have features printed on its 
surface to represent features that are identifiable on the rear of a 
typical passenger vehicle, such as tail lamps, reflex reflectors, 
windows, and the rear license plate. The proposed color ranges for the 
various surface features, including tires, windows, and reflex 
reflectors are incorporated from ISO 19206-3:2021, Annex B, Tables B.2 
and B.3. Table B.2 specifies the colors of the tires, windows, and 
reflectors, which reflect the colors observed the in the real world. 
The color of the exterior of the vehicle is specified to be a range 
representing the color white, which provides a high color contrast to 
the other identifiable features. White is also a common color for motor 
vehicles.\186\ The proposed reflectivity ranges for the various 
features on the vehicle test device are incorporated from ISO 19206-
3:2021, Annex B, Table B.1. Table B.3 specifies the recommended 
minimum, mean, and maximum color range for the white body, specifically 
the outer cover.
---------------------------------------------------------------------------

    \186\ Globally, white was the most popular color for light 
vehicles in 2021. https://gmauthority.com/blog/2022/02/white-was-
the-most-popular-car-color-again-in-2021/
#:~:text=According%20to%20PPG%2C%2035%20percent,by%20silver%20at%2011
%20percent.
---------------------------------------------------------------------------

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

C. Alternatives Considered

    One alternative test device that NHTSA considered for use in this 
proposal was the agency's self-developed Strikable Surrogate Vehicle 
(SSV) device, which NHTSA currently uses in its NCAP testing of AEB 
performance. NHTSA adopted the use of

[[Page 43223]]

the SSV as part of its 2015 NCAP upgrade, under which the agency began 
testing AEB performance.\187\ The SSV resembles the rear section of a 
2011 Ford Fiesta hatchback. The SSV is constructed primarily from a 
rigid carbon fiber mesh, which allows it to maintain a consistent shape 
over time (unless damaged during testing). To maximize visual realism, 
the SSV shell is wrapped with a vinyl material that simulates paint on 
the body panels and rear bumper, and a tinted glass rear window. The 
SSV is also equipped with a simulated United States specification rear 
license plate. The taillights, rear bumper reflectors, and third brake 
light installed on the SSV are actual original equipment from a 
production vehicle. NHTSA testing shows that AEB systems will recognize 
the SSV and will respond in a way that is comparable to how they would 
respond to an actual vehicle.\188\
---------------------------------------------------------------------------

    \187\ 80 FR 68604.
    \188\ 80 FR 68607.
---------------------------------------------------------------------------

    While the SSV and GVT are both recognized as real vehicles by AEB 
systems from the rear approach aspect, the SSV has several 
disadvantages. The foremost disadvantage of the SSV is how easily it 
can be irreparably damaged when struck by a subject vehicle during 
testing, particularly at high relative velocities. While NHTSA has 
tried to address this issue by attaching a foam bumper to the rear of 
the SSV to reduce the peak forces resulting from an impact by the 
subject vehicle, the SSV can still easily be damaged to a point where 
it can no longer be used if the relative impact speed is sufficiently 
high (greater than 40 km/h (25 mph)); this speed is much lower than the 
maximum relative impact speed of 80 km/h (50 mph) potentially 
encountered during the AEB tests performed at the maximum relative 
speeds proposed in this notice). Also, unlike the GVT, which has its 
movement controlled by precise programming and closed loop control, the 
SSV moves along a monorail secured to the test surface, which may be 
visible to a camera-based AEB system.
    In addition to the vehicle test device specifications, NHTSA seeks 
comment on specifying a set of real vehicles to be used as vehicle test 
devices in AEB testing. UN ECE Regulation No. 152 specifies that the 
lead vehicle be either a regular high-volume passenger sedan or a 
``soft target'' meeting the specifications of ISO 19206-1:2018.\189\ UN 
ECE regulation does not require the use of real vehicles as targets, 
but rather offers them as an alternative to manufacturers to homologate 
their systems, at their choice. Although NHTSA has tentatively 
concluded that the specification in UN ECE Regulation No. 152 of any 
high-volume passenger sedan is not sufficiently specific for an FMVSS, 
NHTSA seeks comment on whether it should create a list of vehicles from 
which NHTSA could choose a lead vehicle for testing. Unlike the UN ECE 
regulation, which provides flexibility to manufacturers, inclusion of a 
list of vehicles would provide flexibility to the agency in the 
assessment of the performance of AEB systems. Such a list would be in 
addition to the vehicle test device proposed in this document, to 
provide assurance of vehicle performance with a wider array of lead 
vehicles. For example, the list could include the highest selling 
vehicle models in 2020.
---------------------------------------------------------------------------

    \189\ U.N. Regulation No. 152, E/ECE/TRANS/505/Rev.3/Add.151/
Amend.1 (Nov. 4, 2020), available at https://unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2020/R152am1e.pdf.
---------------------------------------------------------------------------

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

IX. Proposed Compliance Date Schedule

    NHTSA proposes a two-tiered phase-in schedule for meeting the new 
standard. For heavy 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 must meet the 
proposed heavy vehicle AEB standard. To illustrate, if the final rule 
were published on October 1, 2023, the compliance date would be 
September 1, 2027. For heavy vehicles not currently subject to FMVSS 
No. 136, with some exclusions, those manufactured on or after the first 
September 1 that is four years after the date of publication of the 
final rule must meet the amendments to FMVSS No. 136 that would require 
ESC systems and the proposed AEB requirements. In the provided example 
of a final rule published on October 1, 2023, that date would be 
September 1, 2028. Small-volume manufacturers, final-stage 
manufacturers, and alterers would be provided an additional year, added 
to the dates above, to meet the requirements of this proposal.
    Consistent with 49 U.S.C. 30111(d), NHTSA has tentatively concluded 
that good cause exists for this proposal to take effect more than one 
year after publication of a final rule because it would not be feasible 
for all heavy vehicles to be equipped with AEB systems that meet the 
proposed performance requirements within one year. Furthermore, NHTSA 
seeks comments on whether this proposed phase-in schedule appropriately 
addresses challenges to the implementation of AEB for specific 
categories of heavy vehicles. The agency is particularly interested in 
information about single-unit trucks with permanently installed work-
performing equipment installed on the front of or extending past the 
front of the vehicle (e.g., auger trucks, bucket trucks, cable reel 
trucks, certain car carriers, etc.), where AEB sensors may be located. 
NHTSA seeks comments to discern the best way to implement the 
applicability of AEB on class 3-6 single-unit trucks, considering all 
scenarios such as vehicle configuration, vehicle service applicability, 
and cargo type, which, among other factors, can affect vehicle dynamics 
and drivability. The manufacture of single-unit trucks is more complex 
than that of truck tractors due to wider variations in vehicle weight, 
wheelbase, number of axles, center of gravity height, and cargo type. 
These factors, and others, bear on the calibration and performance of 
ESC. For example, ESC system design depends on vehicle dynamics 
characteristics, such as the total vehicle weight and location of that 
weight (center of gravity), which will differ depending on the final 
vehicle configuration. Because ESC has been a prerequisite for 
voluntary adoption of AEB, single-unit trucks not having had ESC 
requirements suggests that AEB implementation has been slower and that 
there is a need for effective date flexibility.
    NHTSA is also aware that many, if not most, manufacturers of 
single-unit trucks are final-stage manufacturers, which are typically 
small businesses. To

[[Page 43224]]

provide more flexibility to small businesses to meet the proposed rule, 
this NPRM proposes to permit small-volume manufacturers, final-stage 
manufacturers, and alterers an additional year to meet the requirements 
of the final rule. The additional time would provide flexibility to the 
manufacturers to install ESC and collaborate with AEB suppliers to meet 
the proposed requirements.
    FMCSA proposes that vehicles currently subject to FMVSS No. 136 
(i.e., those manufactured on or after August 1, 2019, the initial 
compliance date for 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 the proposed heavy vehicle AEB standard. 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 heavy vehicle AEB standard 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 will require the ESC and AEB systems to be inspected and 
maintained in accordance with Sec.  396.3.

X. Retrofitting

    The Secretary has the statutory authority to promulgate safety 
standards for commercial motor vehicles and equipment subsequent to 
initial manufacture. The Secretary has delegated authority to NHTSA, in 
coordination with FMCSA, to promulgate safety standards for commercial 
motor vehicles and equipment subsequent to initial manufacture when the 
standards are based upon and similar to an FMVSS.\190\
---------------------------------------------------------------------------

    \190\ Sec. 101(f) of Motor Carrier Safety Improvement Act of 
1999 (Pub. L. 106-159; Dec. 9, 1999). 49 CFR 1.95(c).
---------------------------------------------------------------------------

    NHTSA considered, but decided against, proposing to require 
retrofitting of in-service vehicles with GVWR greater than 4,536 kg 
(10,000 lbs.) with AEB systems. NHTSA believes that retrofitting in-
service vehicles with AEB systems could be very complex and costly 
because of the integration between an AEB system and the vehicles' 
chassis, engine, and braking systems. There may be changes that would 
have to be made to an originally manufactured vehicle's systems that 
interface with an AEB system, such as plumbing for new air brake valves 
and lines and a new electronic control unit for a revised antilock 
braking system and a new electronic stability control system. NHTSA 
might also have to develop and establish additional requirements to 
ensure that AEB control components on in-service (used) vehicles are at 
an acceptable level of performance for a compliance test of AEB. This 
would be likely given the uniqueness of each vehicle's maintenance 
condition, particularly for items such as tires and brake components, 
which are foundational for AEB performance (and which are subject to 
high demands of wear-and-tear).
    Nonetheless, although this NPRM does not propose requiring heavy 
vehicles to be equipped with AEB subsequent to initial manufacture, 
NHTSA requests comment on the following issues related to retrofitting 
to learn more about the technical and economic feasibility of a 
retrofit requirement going forward.
     The complexity, cost, and burdens of a requirement to 
retrofit in-service vehicles with AEB.
     The changes that would be needed to an originally 
manufactured vehicle's systems that interface with an AEB system, such 
as plumbing for new air brake valves and lines and a new electronic 
control unit for a revised ABS and a new ESC system.
     Approaches NHTSA could take to identify portions of the 
on-road fleet to which a retrofit requirement could apply. For a 
retrofitting requirement, should the requirement distinguish among in-
service vehicles based on the vehicles' date of manufacture? Is it 
reasonable to assume that older in-service vehicles would have greater 
challenges to meet a retrofit requirement? What should, for example, 
the original manufacture date be of vehicles that should be subject to 
a retrofit requirement?
     Should there be provisions to ensure that the various 
components related to AEB performance (e.g., brakes and tires) are at 
an acceptable level of performance for a compliance test, given the 
uniqueness of the maintenance condition for vehicles in service, 
especially for items particularly subject to wear-and-tear (e.g., brake 
components and tires)?
     Relatedly, would it be warranted to vary the performance 
requirements for retrofitted vehicles, so that the requirements would 
be less stringent for used vehicles? If yes, what would be appropriate 
level of stringency? If not, how can the requirements be adjusted for 
in-service vehicles?
     NHTSA requests comment on other options the agency could 
take to identify portions of the on-road fleet to which a retrofit 
requirement should apply. Are there other voluntary improvements that 
heavy vehicle operators would consider in attaining the benefits 
provided by AEB for their in-service vehicles?

XI. Summary of Estimated Effectiveness, Cost, Benefits, and Comparison 
of Regulatory Alternatives

A. Crash Problem

    NHTSA's assessment of available safety data indicates that between 
2017 and 2019, an average of approximately 60,000 crashes occurred 
annually in which a heavy vehicle rear-ended another vehicle. These 
crashes resulted in an annual average of 388 fatalities, approximately 
30,000 non-fatal injuries, and 84,000 property-damage-only vehicles. 
Additionally, class 3-6 heavy vehicles were involved in approximately 
17,000 rollover and loss of control crashes annually. These crashes 
resulted in 178 fatalities, approximately 4,000 non-fatal injuries, and 
13,000 property-damage-only vehicles annually. In total, these rear-
end, rollover, and loss of control crashes add up to 77,000 annually, 
which represent 1.2 percent of all police-reported crashes and over 14 
percent of all crashes involving heavy vehicles. In total, these 
crashes resulted in 566 fatalities and 34,000 non-fatal injuries. These 
crashes also damaged 97,000 vehicles in property-damage-only crashes.

B. AEB System Effectiveness

    NHTSA evaluated the effectiveness of AEB indicates based on the 
efficacy of the system in avoiding a rear-end crash. This relates to 
the proposed requirement that a vehicle avoid an imminent rear-

[[Page 43225]]

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 the 
effectiveness of AEB systems using performance data from the agency's 
vehicle testing. Effectiveness was assessed against all crash severity 
levels collectively, rather than for specific crash severity levels 
(i.e., minor injury versus fatal).
    The AEB effectiveness estimates were derived from performance data 
from four vehicles tested by NHTSA, 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, and 
decelerating lead vehicle) that are proposed in this notice, 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 into an aggregate effectiveness 
value by vehicle class range and crash scenario, as displayed in Table 
17.

                    Table 17--AEB Effectiveness (%) by Vehicle Class Range and Crash Scenario
----------------------------------------------------------------------------------------------------------------
                                                            Stopped lead      Slower-moving    Decelerating lead
                  Vehicle class range                         vehicle          lead vehicle         vehicle
----------------------------------------------------------------------------------------------------------------
7-8....................................................               38.5               49.2               49.2
3-6....................................................               43.0               47.8               47.8
----------------------------------------------------------------------------------------------------------------

    As shown in Table 17, after aggregating class 7 and class 8 
together, 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 target crashes. For class 3-6, AEB is 43.0 
percent effective against stopped lead vehicle crashes and 47.8 percent 
against slower-moving and decelerating lead vehicle target crashes. 
These effectiveness values are the values used for assessing the 
benefits of this proposed rule. Further detail on the derivation of AEB 
effectiveness can be found in the PRIA accompanying this proposal.

C. ESC System Effectiveness

    ESC effectiveness rates were adopted from those estimated in the 
final regulatory impact analysis for the final rule implementing heavy 
vehicle ESC requirements in FMVSS No. 136.\191\ In that final rule, a 
range of ESC crash avoidance effectiveness was established for the 
first-event rollover crashes but only a single-point estimate was 
established for loss of control crashes. ESC was estimated to be 40 to 
56 percent effective at preventing rollover crashes and 14 percent 
effective at preventing loss-of-control crashes. For simplicity, and to 
correspond with the single-point estimate for loss of control crashes, 
the PRIA used the mid-point between the lower and upper bounds of the 
estimated range as the effectiveness for rollovers.
---------------------------------------------------------------------------

    \191\ Final Regulatory Impact Analysis, FMVSS No. 136 Electronic 
Stability Control on Heavy Vehicles, June 2014, Docket No. NHTSA-
2015-0056.
---------------------------------------------------------------------------

    The propensity for vehicles to experience rollover and loss-of-
control crashes is influenced by their body type and center of gravity, 
and the implementation of ESC varies. ESC was estimated to be less 
effective on class 7 and 8 vehicles than it was on light vehicles, 
especially for rollover crashes.\192\ Vehicle characteristics for class 
3 through 6 vehicles range between that of light trucks and vans and 
class 7 and 8 vehicles, it would be plausible to assume that ESC 
effectiveness would be between the effectiveness estimated in the FMVSS 
No. 126 and FMVSS No. 136 final rules. Nevertheless, this NPRM uses the 
effectiveness estimates from the FMVSS No. 136 final rule.
---------------------------------------------------------------------------

    \192\ Dang, J. (July 2007) Statistical Analyzing of the 
Effectiveness of Electronic Stability Control (ESC) Systems--Final 
Report, DOT HS 810 794, Washington, DC, https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/810794.

            Table 18--ESC Effectiveness (%) by Crash Scenario
------------------------------------------------------------------------
                                                                Loss of
               Vehicle class range                 Rollover     control
------------------------------------------------------------------------
3-6.............................................       48.0        14.0
------------------------------------------------------------------------

D. Avoided Crashes and Related Benefits

    Considering the annual heavy vehicle 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, 155 fatalities, and 8,814 non-fatal injuries annually. 
In addition, the proposed rule would eliminate an estimated 24,828 
PDOVs annually. The benefit estimates include assumptions that likely 
result in the underestimation of the benefits of this proposal because 
it only reflects the benefits from crash avoidance. That is, the 
benefits only reflect those resulting from crashes that are avoided as 
a result of the AEB and ESC performance proposed. It is likely that AEB 
will also reduce the severity of crashes that are not prevented. Some 
of these crashes may include fatalities and significant injuries that 
will be prevented or mitigated by AEB.
    Table 19 tabulates these benefits in two ways, one by vehicle class 
and one by technology. These benefits are measured for the portion of 
the vehicle fleet that has not voluntarily adopted AEB prior to the 
NPRM. These benefits also assume reduced performance under dark or 
hazardous weather conditions. The estimated annual benefits would be 
the undiscounted lifetime benefits once the proposal is fully 
implemented (four years after publication of a final rule). The 
undiscounted lifetime benefits for each new model year of vehicles 
would equal the annual benefits of the on-road fleet when that fleet 
has been fully equipped with this technology. The actual annual 
benefits will increase each year as the on-road vehicle fleet is 
replaced with vehicles that would be subject to the proposed 
requirements.

[[Page 43226]]



                      Table 19--Undiscounted Estimated Annual Benefits of the Proposed Rule
----------------------------------------------------------------------------------------------------------------
                                                                                     Non-fatal
                                                      Crashes       Fatalities       injuries          PDOVs
----------------------------------------------------------------------------------------------------------------
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
----------------------------------------------------------------------------------------------------------------

E. Technology Costs

    The AEB system is estimated to cost $396 per vehicle. The unit cost 
includes all the components, labor cost for training customers, tuning 
the system to ensure the performance of AEB, and the AEB malfunction 
telltale. The component unit costs were based on the agency's 2018 
weight and teardown study, which accounted for scale efficiencies in 
production and labor.\193\ The cost for an ESC system would range from 
$320 to $687, which was calculated by adjusting the assumed unit cost 
for ESC in the FMVSS No. 136 final rule for inflation.\194\ Therefore, 
for vehicles that need both AEB and ESC, the total unit cost would 
range from $716 to $1,083 per affected vehicle.\195\ The total number 
of affected vehicles including trucks and buses are estimated to be 
569,792 units annually: 164,405 units for class 7-8 and 405,387 units 
for class 3-6 vehicles. The total cost corresponding to the estimated 
annual benefits is estimated to be $353 million ($288 million for class 
7-8 and $65 million for class 3-6). The affected vehicle units were 
based on the 10 year average of units sold between 2011 and 2020.\196\
---------------------------------------------------------------------------

    \193\ ``Cost and Weight Analysis of Heavy Vehicle Forward 
Collision Warning (FCW) and Automatic Emergency Braking (AEB) 
Systems for Heavy Trucks,'' September 27, 2018, Contract number: 
DTNH2216D00037, Task Order: DTNH2217F00147.
    \194\ Final Regulatory Impact Analysis, FMVSS No. 136 Electronic 
Stability Control on Heavy Vehicles, June 2014, Docket No. NHTSA-
2015-0056.
    \195\ AEB and ESC unit cost estimates are the additional 
component costs for the vehicles without the systems. Specifically, 
AEB cost is the additional hardware to those vehicles that already 
had ESC.
    \196\ Due to data constraints, the average is only available for 
trucks and school buses. The annual sales volume for motorcoaches 
and transit buses was based on the agency's estimate for earlier 
final rules and other sources. Please consult Appendix B of the PRIA 
for details.
---------------------------------------------------------------------------

F. Monetized Benefits

    Table 20 summarizes the primary benefit cost estimates, which 
include the annual total cost, total monetized savings, cost per 
equivalent life saved, and net benefits of the proposed rule under 
three and seven percent discount rates. Monetized savings are measured 
by comprehensive costs, which include the tangible costs of reducing 
fatalities and injuries such as savings from medical care, emergency 
services, insurance administration, workplace costs, legal costs, 
congestion and property damage, lost productivity as well as 
nontangible cost of quality life lost. The nontangible cost components 
were based on the value of statistical life of $11.8 million.\197\
---------------------------------------------------------------------------

    \197\ Departmental Guidance on Valuation of a Statistical Life 
in Economic Analysis, Effective Date: Friday, March 4, 2022, https://www.transportation.gov/office-policy/transportation-policy/revised-departmental-guidance-on-valuation-of-a-statistical-life-in-economic-analysis.
---------------------------------------------------------------------------

    The proposed rule would generate a net benefit of $1.81 billion to 
$2.58 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, a value less than 
$12.2 million (the comprehensive cost of a fatality). The negative net 
cost per fatal equivalent for the 3 percent discount rate indicates 
that the savings from reducing traffic congestion and property damage 
is greater than the total cost of the proposed rule. Net benefits are 
likely to be even higher given that the estimates only include benefits 
from crashes prevented by AEB, but do not include benefits from crashes 
for which AEB mitigates the severity of, but does not prevent.

 Table 20--Estimated Annual Cost, Monetized Benefits, Cost-Effectiveness, and Net Benefits of the Proposed Rule
                                           [2021 dollars in millions]
----------------------------------------------------------------------------------------------------------------
                                                                               Net cost per
           Discount rates               Annual cost *    Monetized savings   fatal equivalent     Net benefits
----------------------------------------------------------------------------------------------------------------
3 Percent...........................             $353.3           $2,937.0           **-$0.12           $2,583.7
7 Percent...........................              353.3            2,160.4               0.50            1,807.1
----------------------------------------------------------------------------------------------------------------
* Annual cost is not discounted because it is paid at vehicle purchase.
** At a three percent discount rate, savings from reduced traffic congestions and property damages outweigh the
  cost, resulting in negative net cost per equivalent life. The negative value indicates cost-effectiveness.

G. Alternatives

    NHTSA has identified and assessed alternatives to the preferred 
alternative set forth in the proposed regulatory text. The agency 
considered two primary alternatives to the proposed rule.
    The first alternative would not require AEB or ESC on vehicles not 
currently subject to FMVSS No. 136. Eliminating the requirement would 
reduce the burden on heavy vehicle manufacturers associated with 
installing AEB and ESC on vehicles with different body types, but would 
result in significantly fewer

[[Page 43227]]

safety benefits and lives saved. A summary of the costs, benefits, and 
cost-effectiveness associated with Alternative 1 is in Table 21.

                                 Table 21--Discounted Benefits of Alternative 1
                                               [Millions of 2021$]
----------------------------------------------------------------------------------------------------------------
                                                                               Net cost per
                                        Annual cost *    Monetized savings   fatal equivalent     Net benefits
----------------------------------------------------------------------------------------------------------------
3 Percent Discount..................             $65.10            $874.59           **-$1.00            $809.50
7 Percent Discount..................              65.10             662.23              -0.66             597.10
----------------------------------------------------------------------------------------------------------------
* Annual cost is not discounted because it is paid at vehicle purchase.
** At a three percent discount rate, savings from reduced traffic congestions and property damages outweigh the
  cost, resulting in negative net cost per equivalent life. The negative value indicates cost-effectiveness.

    The second alternative would require all class 3-6 heavy vehicles 
to have AEB and ESC within four years, as with the primary agency 
proposal. However, this alternative would include a one-year phase-in 
period beginning three years after publication of the final rule in 
which 50 percent of class 3-6 vehicles would be required to install AEB 
and ESC. This alternative was considered because it has the potential 
to save more lives sooner. This alternative would have the same annual 
cost, savings, net cost per fatal equivalent, and net benefits as the 
primary proposal. However, this alternative would result in added 
benefits from vehicles manufactured in the phase-in period. The 
estimated total additional benefits associated with alternative 2 above 
the primary estimate are summarized in Table 22.

   Table 22--Discounted Additional Benefits of Alternative 2 Above the
                            Primary Proposal
                           [Millions of 2021$]
------------------------------------------------------------------------
                Percent discount                       3           7
------------------------------------------------------------------------
Net Additional Benefit..........................     $830.5      $566.4
------------------------------------------------------------------------

    Detailed benefit-cost calculations of these alternatives are 
discussed in the PRIA. The agency seeks comment on the feasibility of 
the second alternative.
    Because of the significant safety benefits that accrue by including 
Class 3-6 vehicles, and to allow time for the Class 3-6 vehicle 
manufactures to optimize implementations of both ESC and AEB into their 
vehicles, the agency decided not to select either alternative.

XII. Regulatory Notices and Analyses

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

    NHTSA and FMCSA have considered the impact of this rulemaking 
action under Executive Order 12866, as amended by Executive Order 
14094, Executive Order 13563, and the Department of Transportation's 
regulatory procedures. This rulemaking is considered significant under 
section 3(f)(1) of Executive Order 12866, as amended, and was reviewed 
by the Office of Management and Budget under that Executive Order. 
NHTSA and FMCSA have prepared a preliminary regulatory impact analysis 
(PRIA) that assesses the cost and benefits of this proposed rule. The 
benefits, costs and other impacts of this NPRM are discussed in the 
prior section.

Regulatory Flexibility Act

    Pursuant to the Regulatory Flexibility Act of 1980, Public Law 96-
354, 94 Stat. 1164 (5 U.S.C. 601 et seq., as amended), whenever an 
agency is required to publish an NPRM or a final rule, it must prepare 
and make available for public comment a regulatory flexibility analysis 
that describes the effect of the rule on small entities (i.e., small 
businesses, small not-for-profit organizations, and small governmental 
jurisdictions). I certify that this NPRM would not have a significant 
economic impact on a substantial number of small entities.
    NHTSA's proposal would directly affect manufacturers of class 3- 
through 8 trucks, buses, and multipurpose passenger vehicles. Of the 
more than 20 companies who are sole manufacturers or first-stage 
manufacturers of class 3 through 8 vehicles in the United States, NHTSA 
found two companies (Proterra and Workhorse Group, Inc.) that qualify 
as a small entities.\198\ Table 23. Below show the list of heavy duty 
truck manufacturers.
---------------------------------------------------------------------------

    \198\ NHTSA researched MD and HD vehicle manufacturing companies 
and found their estimated number of employees and annual revenue (as 
of Dec 2022) from the following sources: zoominfo.com, 
macrotrends.net, zippia.com, statista.com, and linkedin.com.

                                    Table 23--Heavy Duty Truck Manufacturers
----------------------------------------------------------------------------------------------------------------
                                                                            Annual revenue
              Type                      Company           # Employees         (millions)            Notes
----------------------------------------------------------------------------------------------------------------
Trucks..........................  Autocar company....                487               $126  Parent Company: GVW
                                                                                              Group.
                                  Brightdrop.........                252                138  Parent Company: GM.
                                  Ford...............            186,000            158,060  ...................
                                  GM.................            167,000            156,700  ...................
                                  International......              2,760                721  Parent Company:
                                                                                              Navistar.
                                  Freightliner.......             15,000                450  Parent Company:
                                                                                              Daimler.
                                  Hendrickson                      6,000              1,600  ...................
                                   International.
                                  Mack...............              2,000                671  Parent Company:
                                                                                              Volvo.
                                  Navistar...........             14,500              3,900  ...................
                                  Oshkosh Corp.......             15,000              8,300  ...................
                                  PACCAR.............             31,100             28,800  Subsidiaries:
                                                                                              Kenworth,
                                                                                              Peterbilt.
                                  Ram................            200,000            180,000  Parent Company:
                                                                                              Stellantis.

[[Page 43228]]

 
                                  Shyft Group........              4,200              1,000  ...................
                                  Western Star.......              3,221                680  Parent Company:
                                                                                              Daimler.
                                  Workhorse..........                331                  5  Small Business.
Buses...........................  Bluebird...........              1,702                726  ...................
                                  Forest River.......             11,000              3,300  Parent Company:
                                                                                              Berkshire
                                                                                              Hathaway.
                                  Gillig.............                900                267  Parent Company:
                                                                                              Henry Crown & Co.
                                  IC Bus.............                219                 44  Parent Company:
                                                                                              Navistar.
                                  Nikola.............              1,500                 51  ...................
                                  Proterra...........                938                247  Small Business.
                                  REV group..........              6,800              2,300  Subsidiary: El
                                                                                              Dorado.
                                  Thomas Built Buses.              1,276                288  Parent Company:
                                                                                              Daimler.
----------------------------------------------------------------------------------------------------------------

    Workhorse Group, Inc. currently has about 330 employees. Its 
vehicles are already equipped with ESC and AEB and are unlikely to be 
affected by this proposal. Proterra is a manufacturer of large electric 
transit buses and falls into the small business threshold with about 
9,400 employees. Although its vehicles are not currently equipped with 
AEB, its vehicles sell for approximately $750,000. With such a high 
sale price, NHTSA considers the effect of this rule on the price of the 
vehicle to be de minimis. Accordingly, NHTSA has concluded that this 
proposal would not have a significant economic impact upon these small 
entities. However, NHTSA seeks comment on this conclusion.
    Final stage manufacturers are also affected by this proposal, and 
final stage manufacturers would be considered small entities. According 
to the U.S. Census, there are 570 small businesses in body 
manufacturing for light, medium, and heavy-duty classes.\199\ This 
proposal likely would affect a substantial number of final stage 
manufacturers that are small businesses. It is NHTSA's understanding 
that these small entities rarely make modifications to a vehicle's 
braking system and instead rely upon the pass-through certification 
provided by the first-stage manufacturer, which is not typically a 
small business.. More information about multi-stage vehicle 
manufacturing can be found in section VI.E of this proposal. 
Additionally, this proposal would further accommodate final-stage 
manufacturers by providing them an additional year before compliance is 
required. Therefore, NHTSA does not believe at this time that the 
impacts of this proposal on small entities would be significant.
---------------------------------------------------------------------------

    \199\ 2020 SUSB Annual Data Tables by Establishment Industry, 
``U.S. and states, NAICS, detailed employment sizes.'' https://www.census.gov/data/tables/2020/econ/susb/2020-susb-annual.html.
---------------------------------------------------------------------------

    This rule may also affect purchasers of class 3 through 8 vehicles. 
It is assumed that the incremental costs of this proposal would be 
passed on to these purchasers. Class 7 through 8 vehicles are primarily 
purchased by motor carriers, an industry composed of approximately 
757,652 interstate, intrastate, and hazardous materials motor carriers, 
in which over ninety percent of its companies (687,139) are considered 
small.\200\ Class 3-6 vehicles consisting of work pickup trucks, small 
buses, and moving/cargo vans are purchased and utilized in industries 
where small businesses are not uncommon as well. It is not known 
precisely how frequently small businesses purchase new vehicles 
(instead of used vehicles) affected by the proposed rule, however, 
small entities usually have the option to finance or lease these 
vehicles to mitigate financial burden by spreading out cost over time. 
Table 24 below shows a list of industries, where small businesses may 
be affected by the proposed rule.
---------------------------------------------------------------------------

    \200\ Assume a motor carrier of 10 or less power units is 
considered a small entity, which is very conservative given an SBA 
size standard of $30 million in annual revenue. 2022 Pocket Guide to 
Large Truck and Bus Statistics (December 2022), Federal Motor 
Carrier Safety Administration, p.13.

                         Table 24--SBA Size Standards of Indirectly Affected Industries
----------------------------------------------------------------------------------------------------------------
                                                                                               Size standards in
                  NAICS Code                             NAICS Industry description               millions of
                                                                                                    dollars
----------------------------------------------------------------------------------------------------------------
484110.......................................  General Freight Trucking, Local...............                 30
484122.......................................  General Freight Trucking, Long-Distance,                       30
                                                Truckload.
484122.......................................  General Freight Trucking, Long-Distance, Less                  38
                                                Than Truckload.
484210.......................................  Used Household and Office Goods Moving........                 30
484220.......................................  Specialized Freight (except Used Goods)                        30
                                                Trucking, Local.
484230.......................................  Specialized Freight (except Used Goods)                        30
                                                Trucking, Long-Distance.
485113.......................................  Bus and Other Motor Vehicle Transit Systems...               28.5
485210.......................................  Interurban and Rural Bus Transportation.......                 28
485410.......................................  School & Employee Bus Transportation..........               26.5
485510.......................................  Charter Bus Industry..........................                 17
485991.......................................  Special Needs Transportation..................               16.5
488410.......................................  Motor Vehicle Towing..........................                  8
----------------------------------------------------------------------------------------------------------------


[[Page 43229]]

    FMCSA's proposed requirement would ensure that the benefits 
resulting from CMVs equipped with AEBs are sustained through proper 
maintenance and operation. The cost of maintaining AEB systems is 
minimal and may be covered by regular annual maintenance. Therefore, 
FMCSA does not expect this requirement to have a significant economic 
impact on a substantial number of small entities.
    Additional information concerning the potential impacts of this 
proposal on small businesses is presented in the PRIA accompanying this 
proposal. The agencies seek comment on the effects this NPRM would have 
on small businesses.

National Environmental Policy Act

    The National Environmental Policy Act of 1969 (NEPA) \201\ requires 
Federal agencies to analyze the environmental impacts of proposed major 
Federal actions significantly affecting the quality of the human 
environment, as well as the impacts of alternatives to the proposed 
action.\202\ The Council on Environmental Quality (CEQ)'s NEPA 
implementing regulations direct federal agencies to determine the 
appropriate level of NEPA review for a proposed action; an agency can 
determine that a proposed action normally does not have significant 
effects and is categorically excluded,\203\ or can prepare an 
environmental assessment for a proposed action ``that is not likely to 
have significant effects or when the significance of the effects is 
unknown.'' \204\ When a Federal agency prepares an environmental 
assessment, CEQ's NEPA implementing regulations require it to (1) 
``[b]riefly provide sufficient evidence and analysis for determining 
whether to prepare an environmental impact statement or a finding of no 
significant impact;'' and (2) ``[b]riefly discuss the purpose and need 
for the proposed action, alternatives . . . , and the environmental 
impacts of the proposed action and alternatives, and include a listing 
of agencies and persons consulted.'' \205\
---------------------------------------------------------------------------

    \201\ 42 U.S.C. 4321-4347.
    \202\ 42 U.S.C. 4332(2)(C).
    \203\ 40 CFR 1501.4.
    \204\ 40 CFR 1501.5(a).
    \205\ 40 CFR 1501.5(c).
---------------------------------------------------------------------------

    As discussed further below, FMCSA has determined that its proposed 
action is categorically excluded from further analysis and 
documentation in accordance with FMCSA Order 5610.1.\206\ NHTSA 
determined that there is no similarly applicable categorical exclusion 
for its proposed action and has therefore determined that it is 
appropriate to prepare a Draft Environmental Assessment (EA). The 
preamble provides additional information about the distinction between 
NHTSA and FMCSA's proposed requirements based on each agency's 
statutory authority.
---------------------------------------------------------------------------

    \206\ 69 FR 9680 (Mar. 1, 2004).
---------------------------------------------------------------------------

    This section serves as NHTSA's Draft EA. In this Draft EA, NHTSA 
outlines the purpose and need for the proposed rulemaking, a reasonable 
range of alternative actions the agency could adopt through rulemaking, 
and the projected environmental impacts of these alternatives.
Purpose and Need
    This NPRM preamble and the accompanying PRIA set forth the purpose 
of and need for this action. The preamble and PRIA outline the safety 
need for this proposal, in particular to address safety problems 
associated with heavy vehicles, i.e., vehicles with a GVWR greater than 
4,536 kilograms (10,000 pounds). These heavy vehicles, also referred to 
as Class 3-8 vehicles,\207\ include single unit straight trucks, 
combination trucks, truck tractors, motorcoaches, transit buses, school 
buses, and certain pickup trucks. An annualized average of 2017 to 2019 
data from NHTSA's FARS and CRSS shows heavy vehicles were 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.\208\ 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. 
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 GVWR 
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 GVWR of greater than 11.793 
kilograms (26,000 pounds).
---------------------------------------------------------------------------

    \207\ Class is a vehicle classification system used by the 
Federal Highway Administration of Department of Transportation to 
categorize vehicles into 8 Classes based on vehicle size, weight, 
and number of wheels. The following lists the GVWR for Class 3-8 
heavy vehicles. A complete vehicle class categorization table is 
included in 49 CFR part 565.
    Class GVWR
    Class 3: 4,536-6,350 kg (10,001-14,000 pounds)
    Class 4: 6,351-7,257 kg (14,001-16,000 pounds)
    Class 5: 7,258-8,845 kg (16,001-19,500 pounds)
    Class 6: 8,846-11,793 kg (19,501-26,000 pounds)
    Class 7: 11,794-14,969 kg (26,001-33,000 pounds)
    Class 8: 14,969 kg (33,001 pounds) and above
    \208\ These rear-end crashes are cases where the heavy vehicle 
was the striking vehicle.
---------------------------------------------------------------------------

    To address this safety need, NHTSA proposes to adopt a new FMVSS to 
require AEB systems on certain heavy vehicles.\209\ Current AEB systems 
use radar and camera-based sensors or combinations thereof and build 
upon older FCW-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. 
NHTSA also proposes to amend FMVSS No. 136 to require nearly all heavy 
vehicles to have an ESC system that meets the equipment requirements, 
general system operational capability requirements, and malfunction 
detection requirements of FMVSS No. 136. In addition to requiring 
certain heavy vehicles be equipped with AEB/ESC, the proposed rule 
requires the heavy vehicles to be able to avoid a collision in various 
rear-end crash scenarios at different speeds.
---------------------------------------------------------------------------

    \209\ Some heavy vehicles are excluded from the proposed rule. 
These include those vehicles that are excluded from FMVSS No. 121 
and FMVSS No. 136.
---------------------------------------------------------------------------

    As explained earlier in this preamble, the AEB system improves 
safety by using various sensor technologies and sub-systems that work 
together to detect when the vehicle is in a crash imminent situation, 
to automatically apply the vehicle brakes if the driver has not done 
so, or to apply more braking force to supplement the driver's braking, 
thereby detecting and reacting to an imminent crash. This proposed rule 
is anticipated to address the safety need by mitigating the amount of 
fatalities, non-fatal injuries, and property damage that would result 
from crashes that could potentially be prevented or mitigated because 
of AEB and ESC. This proposed rule is expected to substantially 
decrease risks associated with rear-end, rollover, and loss of control 
crashes.
    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

[[Page 43230]]

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, 
enacted as the Infrastructure Investment and Jobs Act, directing the 
Department to prescribe an FMVSS that requires heavy commercial 
vehicles with FMVSS-required ESC 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 ESC and AEB systems to be on during vehicle operation.
Alternatives
    NHTSA has considered three regulatory alternatives for the proposed 
action and a ``no action alternative.'' Under the no action 
alternative, NHTSA would not issue a final rule requiring that vehicles 
be equipped (installation standards) with systems that meet minimum 
specified performance standards, and manufacturers would continue to 
add these systems voluntarily. However, since the BIL directs NHTSA to 
promulgate a rule that would require heavy vehicles subject to FMVSS 
No. 136 to be equipped with an AEB system, the no action alternative is 
not a permissible option. The proposed standard (the preferred 
alternative) requires specific AEB/ESC installation and performance 
standards for certain Class 3-8 heavy vehicles with a two-tiered phase-
in schedule based on whether the heavy vehicle is currently subject to 
FMVSS No. 136. Alternative 1, which is considered less stringent than 
the preferred alternative, would set AEB/ESC installation and 
performance standards only for vehicles currently subject to FMVSS No. 
136. Alternative 2, which is considered more stringent than the 
preferred alternative, would require a more aggressive phase-in 
schedule for the AEB/ESC installation requirements for Class 3-6 heavy 
vehicles.
    Although these regulatory alternatives differ in phase-in schedule 
and heavy vehicle Class applicability, the functional AEB/ESC 
installation and performance requirements would be the same. Please see 
the preamble and PRIA Chapter 11, Regulatory Alternatives, for more 
information about the preferred alternative and other regulatory 
alternatives, and the proposed standards' requirements.
Environmental Impacts of the Proposed Action and Alternatives
    Based on the purpose and need for the proposed action and the 
regulatory alternatives described above, the primary environmental 
impacts that could potentially result from this rulemaking are 
associated with greenhouse gas (GHG) emissions and air quality, 
socioeconomics, public health and safety, solid waste/property damage/
congestion, and hazardous materials.\210\ Consistent with CEQ 
regulations and guidance, this EA discusses impacts in proportion to 
their potential significance. The effects of the proposed rulemaking 
that were analyzed further are summarized below.
---------------------------------------------------------------------------

    \210\ NHTSA anticipates that the proposed action and 
alternatives would have negligible or no impact on the following 
resources and impact categories, and therefore has not analyzed them 
further: topography, geology, soils, water resources (including 
wetlands and floodplains), biological resources, resources protected 
under the Endangered Species Act, historical and archeological 
resources, farmland resources, environmental justice, and Section 
4(f) properties.
---------------------------------------------------------------------------

Greenhouse Gas Emissions and Air Quality
    NHTSA has previously recognized that additional weight required by 
FMVSS could potentially negatively impact the amount of fuel consumed 
by a vehicle, and accordingly result in GHG emissions or air quality 
impacts from criteria pollutant emissions.\211\ Atmospheric GHGs affect 
Earth's surface temperature by absorbing solar radiation that would 
otherwise be reflected back into space. Carbon dioxide (CO2) 
is the most significant GHG resulting from human activity. Motor 
vehicles emit CO2 as well as other GHGs, including methane 
and nitrous oxides, in addition to criteria pollutant emissions that 
negatively affect public health and welfare.
---------------------------------------------------------------------------

    \211\ Criteria pollutants is a term used to describe the six 
common air pollutants for which the Clean Air Act (CAA) requires the 
Environmental Protection Agency (EPA) to set National Ambient Air 
Quality Standards (NAAQS). EPA calls these pollutants criteria air 
pollutants because it regulates them by developing human health-
based or environmentally based criteria (i.e., science-based 
guidelines) for setting permissible levels.
---------------------------------------------------------------------------

    Additional weight added to a vehicle, like added hardware from 
safety systems, can potentially cause an increase in vehicle fuel 
consumption and emissions. NHTSA analyzed in PRIA Chapter 9.1, 
Technology Unit Costs and Added Weights, the cost associated with 
meeting the performance requirements in the proposed rule, including 
the potential weight added to the vehicle. An AEB system for heavy 
vehicles requires the following hardware: sensors (radar mounted at 
front bumper and, in some cases, camera located at top, inside portion 
of windshield), control units (electronic control unit), display (in 
some cases integrated with existing dash cluster, in other cases, a 
separate display), associated wiring harnesses, mounting hardware 
specific to FCW/AEB system, and other materials and scrap (for 
electronic parts, this category includes labels, soldering materials, 
flux, and fasteners).\212\ Although AEB and ESC have some shared system 
components, NHTSA also estimated that a limited amount of additional 
hardware would be required for ESC systems depending on the vehicle 
class, including accelerometers, yaw rate sensors, and steer angle 
sensors.\213\ Based on a study conducted for NHTSA on the cost and 
weight of heavy vehicle FCW and AEB systems,\214\ NHTSA concluded that 
the added weight for the installation of AEB is estimated to be up to 
3.10 kg (~ 7 lbs) and AEB and ESC combined is up to 6.70 kg (~ 15 lbs). 
These weights are considered negligible compared to the 4,536 kg 
(10,000 lbs) or greater curb weight of Class 3-8 vehicles. NHTSA 
tentatively concluded in the PRIA that the proposed rule is not 
expected to impact the fuel consumption of Class 3-8 vehicles, and 
therefore none of the regulatory alternatives would be presumed to 
result in GHG or criteria pollutant impacts.
---------------------------------------------------------------------------

    \212\ PRIA, at 141.
    \213\ Final Regulatory Impact Analysis, FMVSS No. 136, 
Electronic Stability Control Systems on Heavy Vehicles; Docket No. 
NHTSA-2015-0056-0002, at VI-5.
    \214\ Department of Transportation National Highway Traffic 
Safety Administration Office of Acquisition Management (NPO-320) 
West Building 51-117 1200 New Jersey Avenue SE Washington, DC 20590 
Contract Number: DTNH2216D00037 Task Order: DTNH2217F00147 Cost and 
Weight Analysis of Heavy Vehicle Forward Collision Warning (FCW) and 
Automatic Emergency Braking (AEB) Systems for Heavy Trucks Ricardo 
Inc. Detroit Technical Center Van Buren Twp., MI 48111 USA September 
27, 2018.
---------------------------------------------------------------------------

    NHTSA also analyzed this action for purposes of the Clean Air Act 
(CAA)'s General Conformity Rule.\215\ The

[[Page 43231]]

General Conformity Rule does not require a conformity determination for 
Federal actions that are ``rulemaking and policy development and 
issuance,'' such as this action.\216\ Therefore, NHTSA has determined 
it is not required to perform a conformity analysis for this action.
---------------------------------------------------------------------------

    \215\ Section 176(c) of the CAA, codified at 42 U.S.C. 7506(c); 
To implement CAA Section 176(c), EPA issued the General Conformity 
Rule (40 CFR part 51, subpart W and part 93, subpart B). Pursuant to 
the CAA, the U.S. Environmental Protection Agency (EPA) has 
established a set of National Ambient Air Quality Standards (NAAQS) 
for the following criteria pollutants: carbon monoxide (CO), 
nitrogen dioxide (NO2), ozone, particulate matter (PM) 
less than 10 micrometers in diameter (PM10), PM less than 
2.5 micrometers in diameter (PM2.5), sulfur dioxide 
(SO2), and lead (Pb). EPA requires a ``conformity 
determination'' when a Federal action would result in total direct 
and indirect emissions of a criteria pollutant or precursor 
originating in nonattainment or maintenance areas equaling or 
exceeding the emissions thresholds specified in 40 CFR 93.153(b)(1) 
and (2).
    \216\ 40 CFR 93.153(c)(2)(iii).
---------------------------------------------------------------------------

Socioeconomics
    The socioeconomic impacts of the proposed rule would be primarily 
felt by heavy vehicle and equipment manufacturers, heavy vehicle 
drivers, and other road users that would otherwise be killed or injured 
as a result of heavy vehicle crashes. NHTSA conducted a detailed 
assessment of the economic costs and benefits of establishing the new 
rule in its PRIA. The main economic benefits come primarily from the 
reduction in fatalities and non-fatal injuries (safety benefits). 
Reductions in the severity of heavy vehicle crashes would be 
anticipated to have corresponding reductions in costs for medical care, 
emergency services, insurance administrative costs, workplace costs, 
and legal costs due to the fatalities and injuries avoided. Other 
socioeconomic factors discussed in the PRIA that would affect these 
parties include quantified property damage savings, and additional 
quantified and unquantified impacts like less disruptions to commodity 
flow and improved traffic conditions. Most of these socioeconomic 
benefits are related to public health and safety and are discussed in 
more detail below.

                                                     Table 25--Comparison of Regulatory Alternatives
                                                                     [2021 dollars]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               Net cost per equivalent live saved               Net benefits
              Regulatory option                Relative to the proposed rule ---------------------------------------------------------------------------
                                                                                      3%                 7%                 3%                 7%
--------------------------------------------------------------------------------------------------------------------------------------------------------
Proposed Rule...............................  ..............................          -$118,922           $496,746     $2,583,652,432     $1,807,064,498
--------------------------------------------------------------------------------------------------------------------------------------------------------
Alternative 1: AEB Requirements only for      Less Stringent................         -1,003,884           -662,217        809,485,467        597,125,719
 Class 7-8.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Alternative 2: More Aggressive Phase in       More Stringent................           -118,922            496,746      2,583,652,432      1,807,064,498
 Schedule for Class 3-6.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The total annual cost, considering the implementation of both AEB 
and ESC technologies proposed in this rule, is 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. Please see PRIA for additional information about the annual 
cost, monetized benefits, cost-effectiveness, and net benefits of this 
proposal.
Public Health and Safety
    The affected environment for public health and safety includes 
roads, highways and other driving locations used by heavy vehicle 
drivers, drivers and passengers in light vehicles and other motor 
vehicles, and pedestrians or other individuals who could be injured or 
killed in crashes involving the vehicles regulated by the proposed 
action. In the PRIA, the agency determined the impacts on public health 
and safety by estimating the reduction in fatalities and injuries 
resulting from the decreased crash severity due to the use of AEB 
systems under the regulatory alternatives. Under the proposed standard 
(the preferred alternative), it is expected that the addition of a 
requirement for specific AEB/ESC installation and performance standards 
for certain Class 3-8 heavy vehicles with a two-tiered phase-in 
schedule, would result each year in 151 to 206 equivalent lives saved. 
Under Alternative 1, it is expected that the addition of a less 
stringent requirement that would set AEB/ESC installation and 
performance standards only for Class 7-8 heavy vehicles, with the same 
phase-in schedule as the preferred alternative, would result each year 
in 45 to 60 equivalent lives saved. Under Alternative 2, it is expected 
that the addition of a more stringent requirement that would require a 
more aggressive phase-in schedule for the AEB/ESC installation 
requirements for Class 3-6 heavy vehicles, would result in 94 to 128 
equivalent lives saved in 2024 and 151 to 206 equivalent lives saved in 
2025 onwards. The PRIA discusses this information in further detail.
Solid Waste/Property Damage/Congestion
    Vehicle crashes can generate solid wastes and release hazardous 
materials into the environment. The chassis and engines, as well as 
associated fluids and components of automobiles and the contents of the 
vehicles, can all be deemed waste and/or hazardous materials. Solid 
waste can also include damage to the roadway infrastructure, including 
road surface, barriers, bridges, and signage. Hazardous materials are 
substances that may pose a threat to public safety or the environment 
because of their physical, chemical, or radioactive properties when 
they are released into the environment, in this case as a result of a 
crash. Vehicle crashes also generate socioeconomic and environmental 
effects from congestion as engines idle while drivers are caught in 
traffic jams and slowdowns, in particular from wasted fuel and the 
resulting increased greenhouse gas emissions.\217\
---------------------------------------------------------------------------

    \217\ Blincoe, L.J., Miller, T.R., Zaloshnja, E., & Lawrence, 
B.A. (2015, May). The economic and societal impact of motor vehicle 
crashes, 2010. (Revised) (Report No. DOT HS 812 013). Washington, 
DC: National Highway Traffic Safety Administration.
---------------------------------------------------------------------------

    The proposal is projected to reduce the amount and severity of 
heavy vehicle crashes, and therefore is expected to reduce the quantity 
of solid waste, hazardous materials, and other property damage 
generated by vehicle crashes in the United States, in addition to 
reducing the traffic congestion that occurs as a consequence of a 
crash. Less solid waste translates into cost and environmental savings 
from reductions in the following areas: (1) transport of waste 
material, (2) energy required for recycling efforts, and (3) landfill 
or

[[Page 43232]]

incinerator fees. Less waste will result in beneficial environmental 
effects through less GHG emissions used in the transport of it to a 
landfill, less energy used to recycle the waste, less emissions through 
the incineration of waste, and less point source pollution at the scene 
of the crash that would result in increased emissions levels or 
increased toxins leaking from the crashed vehicles into the surrounding 
environment. Similarly, as mentioned above, less congestion translates 
into economic and environmental benefits from fuel savings and reduced 
GHG emissions, in addition to benefits from the time that drivers are 
not caught in additional traffic congestion.
    As discussed in the PRIA, NHTSA's monetized benefits are calculated 
by multiplying the number of non-fatal injuries and fatalities 
mitigated by their corresponding ``comprehensive costs.'' The 
comprehensive costs include economic costs that are external to the 
value of a statistical life (VSL) costs, such as emergency management 
services or legal costs, and congestion costs. NHTSA calculated the 
monetized benefits attributable to reduced traffic congestion and 
property damage in the PRIA accompanying this proposed rule for the 
proposed action and the regulatory alternatives. As shown in Table 26, 
the monetized benefits from reduced traffic congestion and property 
damage increase as the regulatory alternatives increase the heavy 
vehicle classes covered by the proposal and the proposal's phase-in 
year. Please see PRIA for additional information about the 
comprehensive cost values used in this proposal.

                                Table 26--Congestion and Property Damage Savings
----------------------------------------------------------------------------------------------------------------
              Alternative 1                       Preferred alternative                   Alternative 2
----------------------------------------------------------------------------------------------------------------
     3% Discount          7% Discount        3% Discount        7% Discount       3% Discount      7% Discount
----------------------------------------------------------------------------------------------------------------
$125,337,423.........        $94,904,159       $377,815,690       $278,309,156  2024:            2024:
                                                                                 $243,518,740.    $180,753,307.
                                                                                2025 Onwards:    2025 Onwards:
                                                                                 $377,815,690.    $278,309,156.
----------------------------------------------------------------------------------------------------------------

    While NHTSA did not quantify impacts aside from the monetized 
benefits from congestion and property damage savings, like the specific 
quantity of solid waste avoided from reduced crashes, NHTSA believes 
the benefits would increase relative to the crashes avoided and would 
be relative across the different alternatives. This is based in part on 
NHTSA and FMCSA's previously conducted Draft EA on heavy vehicle speed 
limiting devices.\218\ While that Draft EA analyzed the effects of 
reduced crash severity, there would be similar, if not increasing 
benefits to avoided crashes as a result of the addition of AEB to heavy 
vehicles.\219\ The PRIA discusses information related to quantified 
costs and benefits of crashes, and in particular property damage due to 
crashes, for each regulatory alternative in further detail.
---------------------------------------------------------------------------

    \218\ Speed Limiting Devices Draft Environmental Assessment, DOT 
HS 812 324 (August 2016).
    \219\ Id. at 33 (``Using this procedure, the results in this 
section are expected to be more conservative than if presented in 
terms of crash avoidance.''
---------------------------------------------------------------------------

Cumulative Impacts
    In addition to direct and indirect effects, CEQ regulations require 
agencies to consider cumulative impacts of major Federal actions. CEQ 
regulations define cumulative impacts as the impact ``on the 
environment that result from the incremental [impact] of the action 
when added to . . . other past, present, and reasonably foreseeable 
future actions regardless of what agency (Federal or non-Federal) or 
person undertakes such other actions.'' \220\ NHTSA notes that the 
public health and safety, solid waste/property damage/congestion, air 
quality and GHG emissions, socioeconomic, and hazardous material 
benefits identified in this EA were based on calculations described in 
the PRIA, in addition to other NHTSA actions and studies on motor 
vehicle safety. That methodology required the agency to adjust 
historical figures to reflect vehicle safety rulemakings that have 
recently become effective. As a result, many of the calculations in 
this EA already reflect the incremental impact of this action when 
added to other past actions.
---------------------------------------------------------------------------

    \220\ 40 CFR 1508.1(g)(3).
---------------------------------------------------------------------------

    NHTSA's and other parties' past actions that improve the safety of 
heavy vehicles, as well as future actions taken by the agency or other 
parties that improve the safety of heavy vehicles, could further reduce 
the severity or number of crashes involving these vehicles. Any such 
cumulative improvement in the safety of heavy vehicles would have an 
additional effect in reducing injuries and fatalities and could reduce 
the quantity of solid and hazardous materials generated by crashes. 
Additional federal actions like NHTSA's fuel efficiency standards for 
heavy vehicles, and EPA's GHG and criteria pollutant emissions 
standards for heavy vehicles, could also result in additional decreased 
fuel use and emissions reductions in the future.
Agencies and Persons Consulted
    This preamble describes the various materials, persons, and 
agencies consulted in the development of the proposal.
Finding of No Significant Impact
    Although this rule is anticipated to result in increased FMVSS 
requirements for heavy vehicle manufacturers, NHTSA's analysis 
indicates that it would likely result in environmental and other 
socioeconomic benefits. The addition of regulatory requirements to 
standardize heavy vehicle AEB is anticipated to result in no additional 
fuel consumption (and accordingly, no additional GHG or criteria 
pollutant emissions impacts), increasing socioeconomic and public 
safety benefits depending on the regulatory alternative phase-in year 
and vehicle class applicability requirements from the no-action 
alternative, and an increase in benefits from the reduction in solid 
waste, property damage, and congestion (including associated traffic-
level impacts like a reduction in energy consumption and tailpipe 
pollutant emissions from congestion) from fewer crashes.
    Based on the information in this Draft EA and assuming no 
additional information or changed circumstances, NHTSA expects to issue 
a Finding of No Significant Impact (FONSI).\221\ NHTSA has tentatively 
concluded that none of the impacts anticipated to result from the 
proposed action and alternatives under consideration will have a 
significant effect on the human environment. Such a finding will be 
made only after careful review of all public comments received. A Final 
EA and a FONSI, if appropriate, will be issued as part of the final 
rule.
---------------------------------------------------------------------------

    \221\ 40 CFR 1501.6(a).

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

[[Page 43233]]

FMCSA
    FMCSA analyzed this rule pursuant to the National Environmental 
Policy Act and determined this action is categorically excluded from 
further analysis and documentation in an environmental assessment or 
environmental impact statement under FMCSA Order 5610.1 (69 FR 9680, 
Mar. 1, 2004), Appendix 2, paragraph 6(aa). The Categorical Exclusion 
in paragraph 6(aa) covers regulations requiring motor carriers, their 
officers, drivers, agents, representatives, and employees directly in 
control of CMVs to inspect, repair, and provide maintenance for every 
CMV used on a public road. In addition, this rule does not have any 
effect on the quality of environment.

Executive Order 13132 (Federalism)

    NHTSA has examined this NPRM pursuant to Executive Order 13132 (64 
FR 43255, August 10, 1999) and concludes that no additional 
consultation with States, local governments or their representatives is 
mandated beyond the rulemaking process. The agency has concluded that 
the rulemaking would not have sufficient federalism implications to 
warrant consultation with State and local officials or the preparation 
of a federalism summary impact statement. The NPRM would not have 
``substantial direct effects on the States, on the relationship between 
the national government and the States, or on the distribution of power 
and responsibilities among the various levels of government.''
    NHTSA rules can preempt in two ways. First, the National Traffic 
and Motor Vehicle Safety Act contains an express preemption provision: 
When a motor vehicle safety standard is in effect under this chapter, a 
State or a political subdivision of a State may prescribe or continue 
in effect a standard applicable to the same aspect of performance of a 
motor vehicle or motor vehicle equipment only if the standard is 
identical to the standard prescribed under this chapter. 49 U.S.C. 
30103(b)(1). It is this statutory command by Congress that preempts any 
non-identical State legislative and administrative law addressing the 
same aspect of performance.
    The express preemption provision described above is subject to a 
savings clause under which ``[c]ompliance with a motor vehicle safety 
standard prescribed under this chapter does not exempt a person from 
liability at common law.'' 49 U.S.C. 30103(e). Pursuant to this 
provision, State common law tort causes of action against motor vehicle 
manufacturers that might otherwise be preempted by the express 
preemption provision are generally preserved.
    However, the Supreme Court has recognized the possibility, in some 
instances, of implied preemption of such State common law tort causes 
of action by virtue of NHTSA's rules, even if not expressly preempted. 
This second way that NHTSA rules can preempt is dependent upon there 
being an actual conflict between an FMVSS and the higher standard that 
would effectively be imposed on motor vehicle manufacturers if someone 
obtained a State common law tort judgment against the manufacturer, 
notwithstanding the manufacturer's compliance with the NHTSA standard. 
Because most NHTSA standards established by an FMVSS are minimum 
standards, a State common law tort cause of action that seeks to impose 
a higher standard on motor vehicle manufacturers will generally not be 
preempted. However, if and when such a conflict does exist--for 
example, when the standard at issue is both a minimum and a maximum 
standard--the State common law tort cause of action is impliedly 
preempted. See Geier v. American Honda Motor Co., 529 U.S. 861 (2000).
    Pursuant to Executive Order 13132 and 12988, NHTSA has considered 
whether this proposed rule could or should preempt State common law 
causes of action. The agency's ability to announce its conclusion 
regarding the preemptive effect of one of its rules reduces the 
likelihood that preemption will be an issue in any subsequent tort 
litigation. To this end, the agency has examined the nature (e.g., the 
language and structure of the regulatory text) and objectives of this 
final rule and finds that this rule, like many NHTSA rules, would 
prescribe only a minimum safety standard. As such, NHTSA does not 
intend this NPRM to preempt State tort law that would effectively 
impose a higher standard on motor vehicle manufacturers than that 
established by a final rule. Establishment of a higher standard by 
means of State tort law will not conflict with the minimum standard 
adopted here. Without any conflict, there could not be any implied 
preemption of a State common law tort cause of action.
    FMCSA has determined that this proposed rule would not have 
substantial direct costs on or for States concerning the adoption and 
enforcement of compatible motor carrier safety rules for intrastate 
motor carriers, nor would it limit the policymaking discretion of 
States. Nothing in this document would preempt any State motor carrier 
safety law or regulation. Therefore, this proposed rule would not have 
sufficient federalism implications to warrant the preparation of a 
Federalism Impact Statement related to the delivery of FMCSA's 
programs.

Civil Justice Reform

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

Paperwork Reduction Act (PRA)

    Under the PRA of 1995, a person is not required to respond to a 
collection of information by a Federal agency unless the collection 
displays a valid OMB control number. There are no ``collections of 
information'' (as defined at 5 CFR 1320.3(c)) in this proposed rule.

National Technology Transfer and Advancement Act

    Under the National Technology Transfer and Advancement Act of 1995 
(NTTAA) (Public Law 104-113), all Federal agencies and departments 
shall use technical standards that are developed or adopted by 
voluntary consensus standards bodies, using such technical standards as 
a means to carry out policy objectives or activities determined by the 
agencies and departments. Voluntary consensus standards are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, and business practices) that are developed or adopted by 
voluntary consensus standards bodies, such as the International 
Organization for Standardization (ISO) and SAE International. The NTTAA

[[Page 43234]]

directs Federal agencies to provide Congress, through OMB, explanations 
when a Federal agency decides not to use available and applicable 
voluntary consensus standards.
    NHTSA is proposing to incorporate by reference ISO and ASTM 
standards into this proposed rule. NHTSA considered several ISO 
standards and has proposed to use ISO 19206-3:2021 to specify the 
vehicle test device. NHTSA is incorporating by reference ASTM E1337-19, 
which is already incorporated by reference into many FMVSSs, to measure 
the peak braking coefficient of the testing surface.
    NHTSA considered SAE J3029, Forward Collision Warning and 
Mitigation Vehicle Test Procedure--Truck and Bus, which defines the 
conditions for testing AEB and FCW systems. This document outlines a 
basic test procedure to be performed under specified operating and 
environmental conditions. It does not define tests for all possible 
operating and environmental conditions. The procedures in this SAE 
recommended practice are substantially similar to this proposal. 
Minimum performance requirements are not addressed in SAE J3029.
    In Appendix B of this preamble, NHTSA describes several 
international test procedures and regulations the agency considered for 
use in this NPRM. This proposed rule also has substantial technical 
overlap with the UNECE No. 131 described in the appendix. First, this 
proposed rule and UNECE No. 131 specify a warning and automatic 
emergency braking in lead vehicle crash situations. Several lead 
vehicle scenarios are nearly identical, including the stopped lead 
vehicle and lead vehicle moving scenarios. Finally, NHTSA has based its 
test target for the lead vehicle test device on the ``soft target 
option'' condition contained in UNECE No. 152. As discussed in the 
appendix, this proposed rule differs from the UNECE standards in the 
areas of maximum test speed and the basic performance criteria. This 
proposed rule uses higher test speeds to better match the safety 
problem in the United States. This proposed rule includes a requirement 
that the test vehicle avoid contact. This approach would increase the 
repeatability of the test and maximize the realized safety benefits of 
the rule.

Incorporation by Reference

    Under regulations issued by the Office of the Federal Register (1 
CFR 51.5(a)), an agency, as part of a proposed rule that includes 
material incorporated by reference, must summarize material that is 
proposed to be incorporated by reference and discuss the ways the 
material is reasonably available to interested parties or how the 
agency worked to make materials available to interested parties.
    In this NPRM, NHTSA proposes to incorporate by reference three 
documents into the Code of Federal Regulations, one of which is already 
incorporated by reference. The document already incorporated by 
reference into 49 CFR part 571 is ASTM E1337, ``Standard Test Method 
for Determining Longitudinal Peak Braking Coefficient (PBC) of Paved 
Surfaces Using Standard Reference Test Tire.'' ASTM E1337 is a standard 
test method for evaluating peak braking coefficient of a test surface 
using a standard reference test tire using a trailer towed by a 
vehicle. NHTSA uses this method in all of its braking and electronic 
stability control standards to evaluate the test surfaces for 
conducting compliance test procedures.
    NHTSA is also proposing to incorporate by reference into part 571 
SAE J2400, ``Human Factors in Forward Collision Warning System: 
Operating Characteristics and User Interface Requirements.'' SAE J2400 
is an information report that is intended as a starting point of 
reference for designers of forward collision warning systems. NHTSA 
would incorporate this document by reference solely to specify the 
location specification and symbol for a visual forward collision 
warning.
    NHTSA is proposing to incorporate by reference ISO 19206-3:2021(E), 
``Test devices for target vehicles, vulnerable road users and other 
objects, for assessment of active safety functions --Part 3: 
Requirements for passenger vehicle 3D targets.'' This document provides 
specification of three-dimensional test devices that resemble real 
vehicles. It is designed to ensure the safety of the test operators and 
to prevent damage to subject vehicles in the event of a collision 
during testing. NHTSA is referencing many, but not all, of the 
specifications of ISO 19206-3:2021(E), as discussed in section VIII.B 
of this NPRM.
    All standards proposed to be incorporated by reference in this NPRM 
are available for review at NHTSA's headquarters in Washington, DC, and 
for purchase from the organizations promulgating the standards. The 
ASTM standard presently incorporated by reference into other NHTSA 
regulations is also available for review at ASTM's online reading 
room.\222\
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    \222\ https://www.astm/org/READINGLIBRARY/.
---------------------------------------------------------------------------

Unfunded Mandates Reform Act

    The Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4) requires 
agencies to prepare a written assessment of the costs, benefits, and 
other effects of proposed or final rules that include a Federal mandate 
likely to result in the expenditures by States, local or tribal 
governments, in the aggregate, or by the private sector, $100 million 
or more (adjusted annually for inflation with base year of 1995) in any 
one year. Adjusting this amount by the Consumer Price Index for All-
Urban Consumers (CPI-U) for the year 2021 and 1995 results in an 
estimated current value of $178 million (= 2021 index value of 270.970/
1995 index value of 152.400). This proposed rule is not likely to 
result in expenditures by State, local, or tribal governments of more 
than $178 million in any one year. However, it is estimated to result 
in the expenditures by motor vehicle manufacturers of more than $178 
million. The prior section of this NPRM contains a summary of the costs 
and benefits of this proposed rule, and the PRIA discusses the costs 
and benefits of this proposed rule in detail.

Executive Order 13609 (Promoting International Regulatory Cooperation)

    The policy statement in section 1 of E.O. 13609 states, in part, 
that the regulatory approaches taken by foreign governments may differ 
from those taken by U.S. regulatory agencies to address similar issues 
and that, in some cases, the differences between the regulatory 
approaches of U.S. agencies and those of their foreign counterparts 
might not be necessary and might impair the ability of American 
businesses to export and compete internationally. The E.O. states that, 
in meeting shared challenges involving health, safety, labor, security, 
environmental, and other issues, international regulatory cooperation 
can identify approaches that are at least as protective as those that 
are or would be adopted in the absence of such cooperation and that 
international regulatory cooperation can also reduce, eliminate, or 
prevent unnecessary differences in regulatory requirements. NHTSA 
requests public comment on the ``regulatory approaches taken by foreign 
governments'' concerning the subject matter of this rulemaking.

Regulation Identifier Number

    The Department of Transportation assigns a regulation identifier 
number (RIN) to each regulatory action listed in the Unified Agenda of 
Federal Regulations. The Regulatory Information Service Center 
publishes the Unified

[[Page 43235]]

Agenda in April and October of each year. You may use the RINs 
contained in the heading at the beginning of this document to find this 
action in the Unified Agenda.

Plain Language

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

XV. Public Participation

How long do I have to submit comments?

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

How do I prepare and submit comments?

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

How can I be sure that my comments were received?

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

How do I submit confidential business information?

NHTSA
    If you wish to submit any information under a claim of 
confidentiality, you should submit three copies of your complete 
submission, including the information you claim to be confidential 
business information (CBI), to the Chief Counsel, NHTSA, at the address 
given above under FOR FURTHER INFORMATION CONTACT. In addition, you 
should submit two copies, from which you have deleted the claimed 
confidential business information, to Docket Management at the address 
given above under ADDRESSES. When you send a comment containing 
information claimed to be confidential business information, you should 
include a cover letter setting forth the information specified in our 
confidential business information regulation. (49 CFR part 512). To 
facilitate social distancing during COVID-19, NHTSA is temporarily 
accepting confidential business information electronically. Please see 
https://www.nhtsa.gov/coronavirus/submission-confidential-business-information for details.
FMCSA
    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (5 U.S.C. 552), CBI is exempt from public disclosure. 
If your comments responsive to the NPRM contain commercial or financial 
information that is customarily treated as private, that you actually 
treat as private, and that is relevant or responsive to the NPRM, it is 
important that you clearly designate the submitted comments as CBI. 
Please mark each page of your submission that constitutes CBI as 
``PROPIN'' to indicate it contains proprietary information. FMCSA will 
treat such marked submissions as confidential under the Freedom of 
Information Act, and they will not be placed in the public docket of 
the NPRM. Submissions containing CBI should be sent to Mr. Brian 
Dahlin, Chief, Regulatory Evaluation Division, Office of Policy, FMCSA, 
1200 New Jersey Avenue SE, Washington, DC 20590-0001. Any comments 
FMCSA receives not specifically designated as CBI will be placed in the 
public docket for this rulemaking.

Will the agency consider late comments?

    NHTSA will consider all comments that Docket Management receives 
before the close of business on the comment closing date indicated 
above under DATES. To the extent possible, we will also consider 
comments that Docket Management receives after that date. If Docket 
Management receives a comment too late for us to consider in developing 
the final rule, we will consider that comment as an informal suggestion 
for future rulemaking action. FMCSA will consider all comments and 
material received during the comment period and through the closing 
date up to 11:59:59 p.m. ET.

How can I read the comments submitted by other people?

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

[[Page 43236]]

Accordingly, we recommend that you periodically check the Docket for 
new material.

XIV. Appendices to the Preamble

Appendix A: Description of Technologies

    For the convenience of readers, this section describes various 
technologies of an AEB system. An AEB system employs multiple sensor 
technologies and sub-systems that work together to sense a crash 
imminent scenario and, where applicable, automatically apply the 
vehicle brakes to avoid or mitigate a crash. Current systems utilize 
radar- and camera-based sensors. AEB has been implemented in 
vehicles having electronic stability control technology, which 
itself leverages antilock braking system technologies. It also 
builds upon older forward collision warning-only systems.

Radar-Based Sensors

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

Camera Sensors

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

Electronically Modulated Braking Systems

    Automatic actuation of the vehicle brakes requires more than 
just systems to sense when a collision is imminent. Regardless of 
how good a sensing system is, hardware is needed to physically apply 
the brakes without relying on the driver to modulate the brake 
pedal. The automatic braking system leverages two foundational 
braking technologies, antilock braking systems and electronic safety 
control.
    Antilock brakes are a foundational technology that automatically 
controls the degree of wheel slip during braking to prevent wheel 
lock and minimize skidding, by sensing the rate of angular rotation 
of the wheels and modulating the braking force at the wheels to keep 
the wheels from slipping. Modern ABS systems have wheel speed 
sensors and independent brake modulation at each wheel and can 
increase and decrease braking pressures as needed.
    ESC builds upon the antilock brakes and increases their 
capability with the addition of at least two sensors, a steering 
wheel angle sensor and an inertial measurement unit. These sensors 
allow the ESC controller to determine intended steering direction 
(from the steering wheel angle sensor), compare it to the actual 
vehicle direction, and then apply appropriate braking forces at each 
wheel to induce a counter yaw when the vehicle starts to lose 
lateral stability. AEB uses the hardware needed for ESC and 
automatically applies the brakes to avoid certain scenarios where a 
crash with a vehicle is imminent.

Forward Collision Warning

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

Automatic Emergency Braking

    Unlike systems that only alert, AEB systems (systems that 
automatically apply the brakes), are designed to actively help 
drivers avoid or mitigate the severity of rear-end crashes. AEB has 
been previously broken into two primary functions, crash imminent 
braking and dynamic brake support. CIB systems provide automatic 
braking when forward-looking sensors indicate that a crash is 
imminent and the driver has not applied

[[Page 43237]]

the brakes, whereas DBS systems use the same forward-looking 
sensors, but provides supplemental braking after the driver applies 
the brakes when sensors determine that driver-applied braking is 
insufficient to avoid an imminent rear-end crash. This NPRM does not 
split the terminology of these functionalities and instead discusses 
them together as ``AEB.'' In some crash situations, AEB functions 
independently of the driver's use of the brake pedal (CIB), while in 
other situations, the vehicle uses the driver's pedal input to 
better evaluate the situation and avoid the crash (in the light 
vehicle context, this is called DBS). This proposal considers each 
function necessary to address the safety need and presents a 
performance-based regulatory approach that can permit the detailed 
application of each function to be based on the specific vehicle 
application and the manufacturer's approach to meeting the standard.
    In response to an FCW alert or a driver noticing an imminent 
crash scenario, a driver may initiate braking to avoid a rear-end 
crash. In situations where the driver's braking is insufficient to 
prevent a collision, the AEB system can automatically supplement the 
driver's braking action to prevent or mitigate the crash. Similar to 
FCW systems, AEB systems employ forward-looking sensors such as 
radar and vision-based sensors to detect vehicles in the path 
directly ahead and monitor a vehicle's operating conditions such as 
speed or brake application. However, AEB systems can also actively 
supplement braking to assist the driver whereas FCW systems serve 
only to warn the driver of a potential crash threat.
    If a driver does not take any action to brake when a rear-end 
crash is imminent, AEB systems utilize the same types of forward-
looking sensors to apply the vehicle's brakes automatically to slow 
or stop the vehicle. The amount of braking applied varies by 
manufacturer, and several systems are designed to achieve maximum 
vehicle deceleration just prior to impact. This NPRM would not 
directly require a particular deceleration capability but specifies 
situations in which crash avoidance must be achieved. Avoidance may 
be produced by a combination of warnings, vehicle deceleration, and 
AEB application timing.

Appendix B: International Regulatory Requirements and Other Standards

European Union (EU)

    UNECE 131: Uniform provisions concerning the approval of motor 
vehicles regarding the Advanced Emergency Braking Systems (AEBS).
    Europe mandated AEBS for nearly all heavy vehicles starting in 
November 2013. The mandate requires warning and automatic braking on 
Lead Vehicle Moving (LVM) and Stopped lead vehicle (LVS), but it 
does not require Dynamic Braking Support (DBS). It also requires 
Forward Collision Warning (FCW) in 2 of 3 modes (audio, visual, 
haptic). This mandate was implemented into two phases. Phase 1, 
which is for new types (i.e., an all-new vehicle configuration) was 
mandated in November 2013, and new vehicles in November 2015. Phase 
2 which covers more stringent implementations, was put in place for 
the new types in November 2016 and all new heavy vehicles in 
November 2018. The requirements apply to buses and trucks over 3,500 
kg (7,716 lbs.). EU regulations include an electronic stability 
control (ESC) requirement for all heavy-duty vehicle segments.
    The United Nations Economic Commission for Europe (UNECE) is the 
main entity that regulates vehicle safety in the European Union. 
UNECE has developed regulations for the implementation of AEBS 
(using a type approval process) in motor vehicles, as described 
below (UNECE Regulation 131). Regarding AEBS test procedures, the 
lead-vehicle-moving scenario in UNECE regulations has a subject 
vehicle speed of 80 km/h (50 mph). For the lead-vehicle-stopped 
scenario, the subject vehicle speed is also 80 km/h (50 mph).
    In addition, it also has false positive test requirements for 
vehicle speeds of 50 km/h (31 mph). However, these false positive 
test requirements are different from the ones in NHTSA's proposal, 
because NHTSA uses a steel trench plate and pass-through vehicles, 
as opposed to UNECE, which only uses pass-through vehicles.
    There are similarities between the performance requirements of 
the UNECE regulation and proposed FMVSS No. 128 as the speeds of the 
subject vehicle in the scenarios of stopped lead vehicle as well as 
slow moving lead vehicle are the same. However, the UNECE regulation 
does not have performance requirements for decelerating lead vehicle 
scenarios, which NHTSA does have. Because NHTSA has tentatively 
determined it is important to have a decelerating lead vehicle test 
scenario, NHTSA decided not to completely base its requirements on 
the UNECE regulation parameters.
    We note that UNECE 131 is considering the implementation of 
Automatic Emergency Braking-Pedestrian (PAEB) into its existing 
regulation. NHTSA is not proposing PAEB for heavy vehicles in this 
NPRM. NHTSA believes there are unknowns at this time about the 
performance of PAEB on heavy vehicles in the U.S., as well as cost 
and other technical and practicability considerations to support a 
proposed implementation of PAEB for heavy vehicles. Rather than 
delay this NPRM to obtain this information, we have decided to 
proceed with the rulemaking as set forth in this NPRM.

Japan

    In January 2017, the Japanese government, under the Ministry of 
Land, Infrastructure, Transport and Tourism (MLIT) presented a 
proposal for UN Regulation on AEBS for M1/N1 vehicles.\223\ As part 
of the harmonization efforts under consideration by the UNECE 
working group (WP.29), MLIT proposed a new United Nations regulation 
on AEBS in September 2008, initially including M2, N2, M3 and N3 
vehicles, and having as a future target M1 and N1 vehicles. NHTSA's 
consideration of UNECE Regulation 131 is discussed above.
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    \223\ https://unece.org/DAM/trans/doc/2017/wp29grrf/GRRF-83-17e.pdf.
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South Korea

    The Republic of Korea (ROK), under the Ministry of Land, 
Infrastructure and Transport (MOLIT), in January 2019 required all 
passenger vehicles to have AEBS and lane departure warning systems. 
Those requirements were applied to trucks and other vehicles in July 
2021. Article 90-3 (Advanced Emergency Braking System (AEBS)) from 
the Korean standard applies to buses and trucks/special purpose 
vehicle with a gross vehicle weight more than 3.5 tons (over 3,500 
kg) (7,716 lbs.).\224\ The majority of the performance requirements 
from the Korean standard is derived from UNECE Regulation 131. 
NHTSA's consideration of ECE Regulation 131 is discussed above.
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    \224\ Regulations for Performance sand Safety Standards of Motor 
Vehicle and Vehicle Parts: Article 90-3 and Table 7-8.
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SAE International (SAE)

    SAE J3029: Forward Collision Warning and Mitigation Vehicle Test 
Procedure--Truck and Bus.
    This SAE Recommended Practice (RP) establishes uniform powered 
vehicle level test procedures for Forward Collision Avoidance and 
Mitigation (FCAM) systems (also identified as AEB systems) used in 
highway commercial vehicles and coaches greater than 4,535 kg 
(10,000 lbs.) GVWR. This document outlines a basic test procedure to 
be performed under specified operating and environmental conditions. 
It does not define tests for all possible operating and 
environmental conditions. Minimum performance requirements are not 
addressed in this document.
    When comparing the SAE test procedure with proposed FMVSS No. 
128, the SAE procedure specifies lower test conditions than NHTSA's 
proposal. The SAE subject vehicle speed for the stopped lead vehicle 
scenario is 40.2 km/h (25 mph), compared to 80 km/h (50 mph) in this 
NPRM. For the case of false activation test parameters, SAE uses 
50.7 km/h (32 mph), compared to 80 km/h (50 mph) used in the NHTSA 
proposed performance requirements. NHTSA is not proposing to use the 
performance requirements from the SAE tests because the agency 
believes they are not stringent enough to provide the level of 
safety benefit the agency seeks for this NPRM.

International Organization for Standardization (ISO)

    ISO 19377: Heavy commercial vehicles and buses--Emergency 
braking on a defined path--Test method for trajectory measurement.
    This standard describes test methods for determining the 
deviation of the path travelled by a vehicle during a braking 
maneuver induced by an emergency braking system from a pre-defined 
desired path. The standard evaluates the vehicle path during and 
following the system intervention. The corrective steering actions 
for keeping the vehicle on the desired path can be applied either by 
the driver or by a steering machine or by a driver assistance 
system.
    This document applies to heavy vehicles equipped with an 
advanced emergency

[[Page 43238]]

braking system, including commercial vehicles, commercial vehicle 
combinations, buses and articulated buses as defined in ISO 3833 
\225\ (trucks and trailers with maximum weight above 3,5 tonnes 
(3,500 kg or 7,716 lbs.) and buses and articulated buses with 
maximum weight above 5 tonnes (5,000 kg or 11,023 lbs.), according 
to ECE and European Commission on vehicle classification, categories 
M3, N2, N3, O3 and O4).
---------------------------------------------------------------------------

    \225\ ISO 3833, ``Road vehicles--Types--Terms and Definitions,'' 
ISO 3833 defines terms relating to some types of road vehicles 
designated according to certain design and technical 
characteristics. ISO 3833--European Standards (en-standard.eu).
---------------------------------------------------------------------------

    NHTSA considered the ISO test procedure but decided it is 
limited because the ISO standard tests braking on a defined path on 
a straight line as well as braking in a constant radius curve, which 
NHTSA does not. Therefore, NHTSA is not proposing performance 
requirements based on the ISO standard.

Proposed Regulatory Text

List of Subjects

49 CFR Part 393

    Highways and roads, Motor carriers, Motor vehicle equipment, Motor 
vehicle safety.

49 CFR Part 396

    Highway safety, Motor carriers, Motor vehicle safety, Reporting and 
recordkeeping requirements.

49 CFR Part 571

    Imports, Incorporation by reference, Motor vehicle safety, 
Reporting and recordkeeping requirements, Tires.

49 CFR Part 596

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

    In consideration of the foregoing, FMCSA proposes to amend 49 CFR 
parts 393 and 396, and NHTSA proposes to amend part 571 and add part 
596 as follows:

PART 393--PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION

0
1. The authority citation for 49 CFR part 393 is amended to read as 
follows:

    Authority:  49 U.S.C. 31136, 31151, and 31502; sec. 1041(b) of 
Pub. L. 102-240, 105 Stat. 1914, 1993 (1991); sec. 5301 and 5524 of 
Pub. L. 114-94, 129 Stat. 1312, 1543, 1560; sec. 23010, Pub. L. 117-
58, 135 Stat. 429, 766-767, and 49 CFR 1.87.

0
2. Amend Sec.  393.5 by adding, in alphabetical order, the definition 
for ``Automatic emergency braking (AEB) system'' and ``Electronic 
stability control system or ESC system'' to read as follows:


Sec.  393.5   Definitions.

* * * * *
    Automatic emergency braking (AEB) system is a system that detects 
an imminent collision with vehicles, objects, and road users in or near 
the path of a vehicle and automatically controls the vehicle's service 
brakes to avoid or mitigate the collision.
    Electronic stability control system or ESC system means a system 
that has all of the following attributes:
    (1) It augments vehicle directional stability by having the means 
to apply and adjust the vehicle brake torques individually at each 
wheel position on at least one front and at least one rear axle of the 
vehicle to induce correcting yaw moment to limit vehicle oversteer and 
to limit vehicle understeer;
    (2) It enhances rollover stability by having the means to apply and 
adjust the vehicle brake torques individually at each wheel position on 
at least one front and at least one rear axle of the vehicle to reduce 
lateral acceleration of a vehicle;
    (3) It is computer-controlled with the computer using a closed-loop 
algorithm to induce correcting yaw moment and enhance rollover 
stability;
    (4) It has a means to determine the vehicle's lateral acceleration;
    (5) It has a means to determine the vehicle's yaw rate and to 
estimate its side slip or side slip derivative with respect to time;
    (6) It has a means to estimate vehicle mass or, if applicable, 
combination vehicle mass;
    (7) It has a means to monitor driver steering inputs;
    (8) It has a means to modify engine torque, as necessary, to assist 
the driver in maintaining control of the vehicle and/or combination 
vehicle; and
    (9) When installed on a truck tractor, it has the means to provide 
brake pressure to automatically apply and modulate the brake torques of 
a towed trailer.
* * * * *
0
3. Add Sec.  393.56 to read as follows:


Sec.  393.56   Electronic Stability Control Systems.

    (a) Truck tractors manufactured between August 1, 2019 and [the 
first September 1 that is 5 years after the date of publication of a 
final rule]. Each truck tractor (except as provided by 49 CFR 571.136, 
paragraph S3.1 or truck tractors engaged in driveaway-towaway 
operations) with a gross vehicle weight rating of greater than 11,793 
kilograms (26,000 pounds) manufactured on or after August 1, 2019, but 
before [the first September 1 that is 5 years after the date of 
publication of a final rule], must be equipped with an electronic 
stability control (ESC) system that meets the requirements of Federal 
Motor Vehicle Safety Standard No. 136 (49 CFR 571.136).
    (b) Buses manufactured between August 1, 2019 and [the first 
September 1 that is 5 years after the date of publication of a final 
rule]. Each bus (except as provided by 49 CFR 571.136, paragraph S3.1 
or buses engaged in driveaway-towaway operations) with a gross vehicle 
weight rating of greater than 11,793 kilograms (26,000 pounds) 
manufactured on or after August 1, 2019, but before [the first 
September 1 that is 5 years after the date of publication of a final 
rule], must be equipped with an ESC system that meets the requirements 
of FMVSS No. 136.
    (c) Commercial motor vehicles manufactured on and after [the first 
September 1 that is 5 years after the date of publication of a final 
rule]. Trucks and buses, with a GVWR greater than 4,536 kilograms 
(10,000 pounds) and truck tractors manufactured on or after [the first 
September 1 that is 5 years after the date of publication of a final 
rule] (except trucks, buses, and truck tractors engaged in driveaway-
towaway operations), must be equipped with an electronic stability 
control (ESC) system that meets the requirements of Federal Motor 
Vehicle Safety Standard No. 136 (49 CFR 571.136).
    (d) ESC Malfunction Detection. Each truck, truck tractor and bus 
must be equipped with an indicator lamp, mounted in front of and in 
clear view of the driver, which is activated whenever there is a 
malfunction that affects the generation or transmission of control or 
response signals in the vehicle's electronic stability control system.
0
4. Add Sec.  393.57 to read as follows:


Sec.  393.57  Automatic Emergency Braking Systems.

    (a) Truck tractors manufactured on or after [the first September 1 
that is 3 years after the date of publication of a final rule]. Each 
truck tractor (except as provided by 49 CFR 571.136, paragraph S3.1 or 
truck tractors engaged in driveaway-towaway operations) with a gross 
vehicle weight rating of greater than 11,793 kilograms (26,000 pounds) 
manufactured on or after the first September 1 that is 3 years after 
the date of publication of a final rule], must be equipped with an 
automatic emergency brake (AEB) system that meets the requirements of 
Federal Motor Vehicle Safety Standard No. 128 (49 CFR 571.128).

[[Page 43239]]

    (b) Buses manufactured on or after [the first September 1 that is 3 
years after the date of publication of a final rule]. Each bus (except 
as provided by 49 CFR 571.136, paragraph S3.1 or buses engaged in 
driveaway-towaway operations) with a gross vehicle weight rating of 
greater than 11,793 kilograms (26,000 pounds) manufactured on or after 
the first September 1 that is 3 years after the date of publication of 
a final rule], must be equipped with an AEB system that meets the 
requirements of FMVSS No. 128.
    (c) Commercial motor vehicles manufactured on and after [the first 
September 1 that is 5 years after the date of publication of a final 
rule]. Trucks and buses, with a GVWR greater than 4,536 kilograms 
(10,000 pounds) and truck tractors manufactured on or after [the first 
September 1 that is 5 years after the date of publication of a final 
rule] (except trucks, buses, and truck tractors engaged in driveaway-
towaway), must be equipped with an AEB system that meets the 
requirements of Federal Motor Vehicle Safety Standard No. 128 (49 CFR 
571.128).
    (d) AEB Malfunction Detection. Each commercial motor vehicle 
subject to FMVSS No. 128 must be equipped with a telltale that meets 
the requirements of S5.3 of FMVSS No. 128 (49 CFR 571.128), mounted in 
front of and in clear view of the driver, which is activated whenever 
there is a malfunction that affects the generation or transmission of 
control or response signals in the vehicle's AEB system.

PART 396--INSPECTION, REPAIR, AND MAINTENANCE

0
5. The authority citation for 49 CFR part 396 is amended to read as 
follows:

    Authority:  49 U.S.C. 504, 31133, 31136, 31151, 31502; sec. 
32934, Pub. L. 112-141, 126 Stat. 405, 830; sec. 5524, Pub. L. 114-
94, 129 Stat. 1312, 1560; sec. 23010, Pub. L. 117-58, 135 Stat. 429, 
766-767 and 49 CFR 1.87.

0
6. Amend Appendix A to Part 396 by adding paragraphs 1.n. and o to read 
as follows:

Appendix A to Part 396--Minimum Periodic Inspection Standards

* * * * *
    1. Brake System

    n. Electronic Stability Control (ESC) System.
    (1) Missing ESC malfunction detection components.
    (2) The ESC malfunction telltale must be identified by the 
symbol shown for ``Electronic Stability Control System Malfunction'' 
or the specified words or abbreviations listed in Table 1 of 
Standard No. 101 (Sec.  571.101).
    (3) The ESC malfunction telltale must be activated as a check-
of-lamp function either when the ignition locking system is turned 
to the ``On'' (``Run'') position when the engine is not running, or 
when the ignition locking system is in a position between the ``On'' 
(``Run'') and ``Start'' that is designated by the manufacturer as a 
check-light position.
    (4) Other missing or inoperative ESC system components.
    o. Automatic Emergency Braking (AEB).
    (1) Missing AEB malfunction telltale components (e.g., bulb/LED, 
wiring, etc.).
    (2) AEB malfunction telltale that does not illuminate while 
power is continuously applied during initial powerup.
    (3) AEB malfunction telltale that stays illuminated while power 
is continuously applied during normal vehicle operation.
    (4) Other missing or inoperative AEB components.
* * * * *

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

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

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

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


Sec.  571.5   Matter incorporated by reference

* * * * *
    (d) * * *
    (34) ASTM E1337-19, ``Standard Test Method for Determining 
Longitudinal Peak Braking Coefficient (PBC) of Paved Surfaces Using 
Standard Reference Test Tire,'' approved December 1, 2019, into 
Sec. Sec.  571.105; 571.121; 571.122; 571.126; 571.128; 571.135; 
571.136; 571.500.
* * * * *
    (l) * * *
    (49) SAE J2400, ``Human Factors in Forward Collision Warning 
System: Operating Characteristics and User Interface Requirements,'' 
August 2003 into Sec.  571.128.
* * * * *
0
9. Add Sec.  571.128 to read as follows:


Sec.  571.128   Standard No. 128; Automatic emergency braking systems 
for heavy vehicles.

    S1. Scope. This standard establishes performance requirements for 
automatic emergency braking (AEB) systems for heavy vehicles.
    S2. Purpose. The purpose of this standard is to reduce the number 
of deaths and injuries that result from crashes in which drivers do not 
apply the brakes or fail to apply sufficient braking power to avoid or 
mitigate a crash.
    S3. Application. This standard applies to multipurpose passenger 
vehicles, trucks, and buses with a gross vehicle weight rating greater 
than 4,536 kilograms (10,000 pounds) that are subject to Sec. Sec.  
571.105 or 571.121 of this part.
    S4. Definitions.
    Adaptive cruise control system is an automatic speed control system 
that allows the equipped vehicle to follow a lead vehicle at a pre-
selected gap by controlling the engine, power train, and service 
brakes.
    Ambient illumination is the illumination as measured at the test 
surface, not including any illumination provided by the subject 
vehicle.
    Automatic emergency braking (AEB) system is a system that detects 
an imminent collision with vehicles, objects, and road users in or near 
the path of a vehicle and automatically controls the vehicle's service 
brakes to avoid or mitigate the collision.
    Brake pedal application onset is when the brake controller begins 
to displace the brake pedal.
    Forward collision warning is an auditory and visual warning 
provided to the vehicle operator by the AEB system that is designed to 
induce an immediate forward crash avoidance response by the vehicle 
operator.
    Forward collision warning onset is the first moment in time when a 
forward collision warning is provided.
    Headway is the distance between the lead vehicle's rearmost plane 
normal to its centerline and the subject vehicle's frontmost plane 
normal to its centerline.
    Lead vehicle is a vehicle test device facing the same direction and 
preceding a subject vehicle within the same travel lane.
    Lead vehicle braking onset is the point at which the lead vehicle 
achieves a deceleration of 0.05g due to brake application.
    Over-the-road bus means a bus characterized by an elevated 
passenger deck located over a baggage compartment, except a school bus.
    Perimeter-seating bus means a bus with 7 or fewer designated 
seating positions rearward of the driver's seating position that are 
forward-facing or can convert to forward-facing without the use of 
tools and is not an over-the-road bus.
    Small-volume manufacturer means an original vehicle manufacturer 
that produces or assembles fewer than 5,000 vehicles annually for sales 
in the United States.

[[Page 43240]]

    Steel trench plate is a rectangular steel plate often used in road 
construction to temporarily cover sections of pavement unsafe to drive 
over directly.
    Subject vehicle is the vehicle under examination for compliance 
with this standard.
    Transit bus means a bus that is equipped with a stop-request system 
sold for public transportation provided by, or on behalf of, a State or 
local government and that is not an over-the-road bus.
    Travel path is the path projected onto the road surface of a point 
located at the intersection of the subject vehicle's frontmost vertical 
plane and longitudinal vertical center plane, as the subject vehicle 
travels forward.
    Vehicle test device is a device meeting the specifications set 
forth in subpart C of 49 CFR part 596.
    S5. Requirements.
    (a) Truck tractors and buses with a GVWR greater than 11,793 
kilograms (26,000 pounds), other than school buses, perimeter-seating 
buses, and transit buses and which are manufactured on or after [the 
first September 1 that is three years after the date of publication of 
a final rule] must meet the requirements of this standard.
    (b) Vehicles with a GVWR greater than 4,536 kilograms (10,000 
pounds) which are manufactured on or after [the first September 1 that 
is four years after the date of publication of a final rule] must meet 
the requirements of this standard.
    (c) The requirements of paragraphs (a) and (b) of this section S5 
do not apply to small-volume manufacturers, final-stage manufacturers 
and alterers until one year after the dates specified in those 
paragraphs.
    S5.1. Requirements when approaching a lead vehicle.
    S5.1.1. Forward Collision Warning. A vehicle is required to have a 
forward collision warning system, as defined in S4 of this section, 
that provides an auditory and visual signal to the driver of an 
impending collision with a lead vehicle when traveling at any forward 
speed greater than 10 km/h (6.2 mph). The auditory signal must have a 
high fundamental frequency of at least 800 Hz, a duty cycle of 0.25--
0.95, and tempo in the range of 6-12 pulses per second. The visual 
signal must be located according to SAE J2400 (incorporated by 
reference, see Sec.  571.5), paragraph 4.1.14, and must include the 
symbol in the bottom right of paragraph 4.1.16. Line of sight is based 
on the forward-looking eye midpoint (Mf) as described in 
S14.1.5 of Sec.  571.111. The symbol must be red in color and steady-
burning.
    S5.1.2. Automatic Emergency Braking. A vehicle is required to have 
an automatic emergency braking system, as defined in S4 of this 
section, that applies the service brakes automatically when a collision 
with a lead vehicle is imminent. The system must operate when the 
vehicle is traveling at any forward speed greater than 10 km/h (6.2 
mph).
    S5.1.3. Performance Test Requirements. The vehicle must provide a 
forward collision warning and subsequently apply the service brakes 
automatically when a collision with a lead vehicle is imminent such 
that the subject vehicle does not collide with the lead vehicle when 
tested using the procedures in S7. The forward collision warning is not 
required if adaptive cruise control is engaged.
    S5.2. False Activation. The vehicle must not automatically apply 
braking that results in peak deceleration of 0.25g or greater when 
manual braking is not applied, nor a peak deceleration of 0.45g or 
greater when manual braking is applied, when tested using the 
procedures in S8.
    S5.3. Malfunction Detection. The system must continuously detect 
system malfunctions, including malfunctions caused solely by sensor 
obstructions. If the system detects a malfunction that prevents the 
system from meeting the requirements specified in S5.1 or S5.2, the 
system must provide the vehicle operator with a telltale that the 
malfunction exists.
    S6. Test Conditions.
    S6.1. Environmental conditions.
    S6.1.1. Temperature. The ambient temperature is any temperature 
between 2 [deg]C and 40 [deg]C.
    S6.1.2. Wind. The maximum wind speed is no greater than 5 m/s (11 
mph) during tests approaching a lead vehicle.
    S6.1.3. Ambient Lighting.
    (a) The ambient illumination on the test surface is any level at or 
above 2,000 lux.
    (b) Testing is not performed while driving toward or away from the 
sun such that the horizontal angle between the sun and a vertical plane 
containing the centerline of the subject vehicle is less than 25 
degrees and the solar elevation angle is less than 15 degrees.
    S6.1.4. Precipitation. Testing is not conducted during periods of 
precipitation or when visibility is affected by fog, smoke, ash, or 
other particulate.
    S6.2. Road conditions.
    S6.2.1. Test Track Surface and Construction. The tests are 
conducted on a dry, uniform, solid-paved surface. Surfaces with debris, 
irregularities, or undulations, such as loose pavement, large cracks, 
or dips are not used.
    S6.2.2. Surface Friction. The road test surface produces a peak 
friction coefficient (PFC) of 1.02 when measured using an ASTM 
International (ASTM) F2493 standard reference test tire, in accordance 
with ASTM E1337-19 (incorporated by reference, see Sec.  571.5), at a 
speed of 64 km/h (40 mph), without water delivery.
    S6.2.3. Slope. The test surface has any consistent slope between 0 
percent and 1 percent.
    S6.2.4. Markings. The road surface within 2.3 m of the intended 
travel path is marked with zero, one, or two lines of any configuration 
or color. If one line is used, it is straight. If two lines are used, 
they are straight, parallel to each other, and at any distance from 2.7 
m to 4.5 m apart.
    S6.2.5. Obstructions. Testing is conducted such that the vehicle 
does not travel beneath any overhead structures, including but not 
limited to overhead signs, bridges, or gantries. No vehicles, 
obstructions, or stationary objects are within 7.4 m of either side of 
the intended travel path except as specified.
    S6.3. Subject vehicle conditions.
    S6.3.1. Malfunction notification. Testing is not conducted while 
the AEB malfunction telltale specified in S5.3 is illuminated.
    S6.3.2. Sensor obstruction. All sensors used by the system and any 
part of the vehicle immediately ahead of the sensors, such as plastic 
trim, the windshield, etc., are free of debris or obstructions.
    S6.3.3. Tires. The vehicle is equipped with the original tires 
present at the time of initial sale. The tires are inflated to the 
vehicle manufacturer's recommended cold tire inflation pressure(s) 
specified on the vehicle's placard or the tire inflation pressure 
label.
    S6.3.4. Brake burnish.
    (a) Vehicles subject to Sec.  571.105 are burnished in accordance 
with S7.4 of that section.
    (b) Vehicles subject to Sec.  571.121 are burnished in accordance 
with S6.1.8 of that section.
    S6.3.5. Brake temperature. The average temperature of the service 
brakes on the hottest axle of the vehicle during testing, measured 
according to S6.1.16 of Sec.  571.121, is between 66[deg]C and 
204[deg]C prior to braking.
    S6.3.6. Fluids. All non-consumable fluids for the vehicle are at 
100 percent capacity. All consumable fluids are at any level from 5 to 
100 percent capacity.

[[Page 43241]]

    S6.3.7. Propulsion battery charge. The propulsion batteries are 
charged at any level from 5 to 100 percent capacity.
    S6.3.8. Cruise control. Cruise control, including adaptive cruise 
control, is configured under any available setting.
    S6.3.9. Adjustable forward collision warning. Forward collision 
warning is configured in any operator-configurable setting.
    S6.3.10. Engine braking. A vehicle equipped with an engine braking 
system that is engaged and disengaged by the operator is tested with 
the system in any selectable configuration.
    S6.3.11. Regenerative braking. Regenerative braking is configured 
under any available setting.
    S6.3.12. Liftable Axles. A vehicle with one or more liftable axles 
is tested with the liftable axles down.
    S6.3.13. Headlamps. Testing is conducted with the headlamp control 
in any selectable position.
    S6.3.14. Subject vehicle loading.
    (a) Except as provided in S6.3.14(b), the vehicle is loaded to its 
GVWR so that the load on each axle, measured at the tire-ground 
interface, is most nearly proportional to the axles' respective GAWRs, 
without exceeding the GAWR of any axle.
    (b) Truck tractors.
    (1) A truck tractor is loaded to its GVWR with the operator and 
test instrumentation, and by coupling it to a control trailer as 
provided in S6.3.14(b)(2) of this section and placing ballast (weight) 
on the control trailer which loads the tractor's non-steer axles. The 
control trailer is loaded with ballast without exceeding the GAWR of 
the trailer axle. The location of the center of gravity of the ballast 
on the control trailer is directly above the kingpin. The height of the 
center of gravity of the ballast on the control trailer is less than 
610 mm (24 inches) above the top of the tractor's fifth-wheel hitch 
(the area where the truck tractor attaches to the trailer). If the 
tractor's fifth-wheel hitch position is adjustable, the fifth-wheel 
hitch is adjusted to proportionally distribute the load on each of the 
tractor's axle(s), according to each axle's GAWR, without exceeding the 
GAWR of any axle(s). If the fifth-wheel hitch position cannot be 
adjusted to prevent the load from exceeding the GAWR of the tractor's 
axle(s), the ballast is reduced until the axle load is equal to or less 
than the GAWR of the tractor's rear axle(s), maintaining load 
proportioning as close as possible to specified proportioning.
    (2) The control trailer is an unbraked, flatbed semi-trailer that 
has a single axle with a GAWR of 8,165 kilograms (18,000 pounds). The 
control trailer has a length of at least 6,400 mm (252 inches), but no 
more than 7,010 mm (276 inches), when measured from the transverse 
centerline of the axle to the centerline of the kingpin (the point 
where the trailer attaches to the truck tractor). At the manufacturer's 
option, truck tractors with four or more axles may use a control 
trailer with a length of more than 7,010 mm (276 inches), but no more 
than 13,208 mm (520 inches) when measured from the transverse 
centerline of the axle to the centerline of the kingpin.
    S6.3.15. AEB system initialization. The vehicle is driven at a 
speed of 10 km/h or higher for at least one minute prior to testing, 
and subsequently the starting system is not cycled off prior to 
testing.
    S6.4. Equipment and test Devices.
    S6.4.1. The vehicle test device is specified in 49 CFR part 596 
subpart C. Local fluttering of the lead vehicle's external surfaces 
does not exceed 10 mm perpendicularly from the reference surface, and 
distortion of the lead vehicle's overall shape does not exceed 25 mm in 
any direction.
    S6.4.2. The steel trench plate used for the false activation test 
has the dimensions 2.4 m x 3.7 m x 25 mm and is made of ASTM A36 steel. 
Any metallic fasteners used to secure the steel trench plate are flush 
with the top surface of the steel trench plate.
    S7. Testing when approaching a lead vehicle.
    S7.1. Setup.
    (a) The testing area is set up in accordance with Figure 1 to this 
section.
    (b) Testing is conducted during daylight.
    (c) For reference, Table 1 to S7.1 specifies the subject vehicle 
speed (VSV), lead vehicle speed (VLV), headway, 
and lead vehicle deceleration for each test that may be conducted.
    (d) The intended travel path of the vehicle is a straight line 
toward the lead vehicle from the location corresponding to a headway of 
L0.
    (e) If the road surface is marked with a single or double lane 
line, the intended travel path is parallel to and 1.8 m from the inside 
of the closest line. If the road surface is marked with two lane lines 
bordering the lane, the intended travel path is centered between the 
two lines.
    (f) For each test run conducted, the subject vehicle speed 
(VSV), lead vehicle speed (VLV), headway, and 
lead vehicle deceleration will be selected from the ranges specified.

                                            Table 1 to S7.1--Test Parameters When Approaching a Lead Vehicle
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    Speed (km/h)
           Test scenarios            -----------------------------------------       Headway (m)         Lead vehicle decel (g)        Manual brake
                                                VSV                  VLV                                                               application
--------------------------------------------------------------------------------------------------------------------------------------------------------
Stopped Lead Vehicle................  Any 10-80..............               0  .......................  .......................  no.
                                      Any 70-100.............               0  .......................  .......................  yes.
Slower-Moving Lead Vehicle..........  Any 40-80..............              20  .......................  .......................  no.
                                      Any 70-100.............              20  .......................  .......................  yes.
Decelerating Lead Vehicle...........  50.....................              50  Any 21-40..............  Any 0.3-0.4............  no.
                                      50.....................              50  Any 21-40..............  Any 0.3-0.4............  yes.
                                      80.....................              80  Any 28-40..............  Any 0.3-0.4............  no.
                                      80.....................              80  Any 28-40..............  Any 0.3-0.4............  yes.
--------------------------------------------------------------------------------------------------------------------------------------------------------

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

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

    S7.3. Stopped lead vehicle.
    S7.3.1. Test parameters.
    (a) For testing with no subject vehicle manual brake application, 
the subject vehicle test speed is any speed between 10 km/h and 80 km/
h, and the lead vehicle speed is 0 km/h.
    (b) For testing with manual brake application of the subject 
vehicle, the

[[Page 43242]]

subject vehicle test speed is any speed between 70 km/h and 100 km/h, 
and the lead vehicle speed is 0 km/h.
    S7.3.2. Test conduct prior to forward collision warning onset.
    (a) The lead vehicle is placed stationary with its longitudinal 
centerline coincident to the intended travel path.
    (b) Before the headway corresponds to L0, the subject 
vehicle is driven at any speed, in any direction, on any road surface, 
for any amount of time.
    (c) The subject vehicle approaches the rear of the lead vehicle.
    (d) Beginning when the headway corresponds to L0, the 
subject vehicle speed is maintained within 1.6 km/h of the test speed 
with minimal and smooth accelerator pedal inputs.
    (e) Beginning when the headway corresponds to L0, the 
subject vehicle heading is maintained with minimal steering input such 
that the travel path does not deviate more than 0.3 m laterally from 
the intended travel path and the subject vehicle's yaw rate does not 
exceed 1.0 deg/s.
    S7.3.3. Test conduct after forward collision warning onset.
    (a) The accelerator pedal is released at any rate such that it is 
fully released within 500 ms. This action is omitted for vehicles 
tested with cruise control active.
    (b) For testing conducted with manual brake application, the 
service brakes are applied as specified in S9. The onset of brake pedal 
application occurs 1.0  0.1 second after forward collision 
warning onset.
    (c) For testing conducted without manual brake application, no 
manual brake application is made until the test completion criteria of 
S7.3.4 are satisfied.
    S7.3.4. Test completion criteria. The test run is complete when the 
subject vehicle comes to a complete stop without making contact with 
the lead vehicle or when the subject vehicle makes contact with the 
lead vehicle.
    S7.4. Slower-moving lead vehicle.
    S7.4.1. Test parameters.
    (a) For testing with no subject vehicle manual brake application, 
the subject vehicle test speed is any speed between 40 km/h and 80 km/
h, and the lead vehicle speed is 20 km/h.
    (b) For testing with manual brake application of the subject 
vehicle, the subject vehicle test speed is any speed between 70 km/h 
and 100 km/h, and the lead vehicle speed is 20 km/h.
    S7.4.2. Test conduct prior to forward collision warning onset.
    (a) The lead vehicle is propelled forward in a manner such that the 
longitudinal center plane of the lead vehicle does not deviate 
laterally more than 0.3m from the intended travel path.
    (b) The subject vehicle approaches the lead vehicle.
    (c) Beginning when the headway corresponds to L0, the 
subject vehicle and lead vehicle speed is maintained within 1.6 km/h of 
the test speed with minimal and smooth accelerator pedal inputs.
    (d) Beginning when the headway corresponds to L0, the 
subject vehicle and lead vehicle headings are maintained with minimal 
steering input such that the subject vehicle's travel path does not 
deviate more than 0.3 m laterally from the centerline of the lead 
vehicle, and the yaw rate of the subject vehicle does not exceed 1.0 deg/s prior to forward collision warning onset.
    S7.4.3. Test conduct after forward collision warning onset.
    (a) The subject vehicle's accelerator pedal is released at any rate 
such that it is fully released within 500 ms. This action is omitted 
for vehicles tested with cruise control active.
    (b) For testing conducted with manual braking application, the 
service brakes are applied as specified in S9. The onset of brake pedal 
application is 1.0  0.1 second after the forward collision 
warning onset.
    (c) For testing conducted without manual braking application, no 
manual brake application is made until the test completion criteria of 
S7.4.4 are satisfied.
    S7.4.4. Test completion criteria. The test run is complete when the 
subject vehicle speed is less than or equal to the lead vehicle speed 
without making contact with the lead vehicle or when the subject 
vehicle makes contact with the lead vehicle.
    S7.5. Decelerating lead vehicle.
    S7.5.1. Test parameters.
    (a) The subject vehicle test speed is 50 km/h or 80 km/h, and the 
lead vehicle speed is identical to the subject vehicle test speed.
    (b) [Reserved]
    S7.5.2. Test conduct prior to lead vehicle braking onset.
    (a) Before the 1 second prior to lead vehicle braking onset, the 
subject vehicle is driven at any speed, in any direction, on any road 
surface, for any amount of time.
    (b) Between 1 second prior to lead vehicle braking onset and lead 
vehicle braking onset:
    (1) The lead vehicle is propelled forward in a manner such that the 
longitudinal center plane of the vehicle does not deviate laterally 
more than 0.3 m from the intended travel path.
    (2) The subject vehicle follows the lead vehicle at a headway of 
any distance between 21 m and 40 m if the subject vehicle test speed is 
50 km/h, or any distance between 28 m and 40 m if the subject vehicle 
test speed is 80 km/h.
    (3) The subject vehicle's speed is maintained within 1.6 km/h of 
the test speed with minimal and smooth accelerator pedal inputs prior 
to forward collision warning onset.
    (4) The lead vehicle's speed is maintained within 1.6 km/h.
    (5) The subject vehicle and lead vehicle headings are maintained 
with minimal steering input such that their travel paths do not deviate 
more than 0.3 m laterally from the centerline of the lead vehicle, and 
the yaw rate of the subject vehicle does not exceed 1.0 
deg/s until forward collision warning onset.
    S7.5.3. Test conduct following lead vehicle braking onset.
    (a) The lead vehicle is decelerated to a stop with a targeted 
average deceleration of any value between 0.3g and 0.4g. The targeted 
deceleration magnitude is achieved within 1.5 seconds of lead vehicle 
braking onset and is maintained until 250 ms prior to coming to a stop.
    (b) After forward collision warning onset, the subject vehicle's 
accelerator pedal is released at any rate such that it is fully 
released within 500 ms. This action is omitted for vehicles with cruise 
control active.
    (c) For testing conducted with manual braking application, the 
service brakes are applied as specified in S9. The brake pedal 
application onset occurs 1.0  0.1 second after the forward 
collision warning onset.
    (d) For testing conducted without manual braking application, no 
manual brake application is made until the test completion criteria of 
S7.5.4 are satisfied.
    S7.5.4. Test completion criteria. The test run is complete when the 
subject vehicle comes to a complete stop without making contact with 
the lead vehicle or when the subject vehicle makes contact with the 
lead vehicle.
    S8. False AEB activation.
    S8.1. Headway calculation. For each test run to be conducted under 
S8.2 and S8.3, the headway (L0, L2.1, L1.1), in meters, between the 
front plane of the subject vehicle and either the steel trench plate's 
leading edge or the rearmost plane normal to the centerline of the 
vehicle test devices providing 5.0 seconds, 2.1 seconds, and 1.1 
seconds time to collision (TTC) is calculated. L0, L2.1, and L1.1 are 
determined with the following equation where VSV is the speed of the 
subject vehicle in m/s:

Lx = TTCx x (VSV)

[[Page 43243]]

TTC0 = 5.0
TTC2.1 = 2.1
TTC1.1 = 1.1


    S8.2. Steel trench plate.
    S8.2.1. Test parameters and setup.
    (a) The testing area is set up in accordance with Figure 2 to this 
section.
    (b) The steel trench plate is secured flat on the test surface so 
that its longest side is parallel to the subject vehicle's intended 
travel path and horizontally centered on the subject vehicle's intended 
travel path.
    (c) The subject vehicle test speed is 80 km/h.
    S8.2.2. Test conduct.
    (a) The subject vehicle approaches the steel trench plate.
    (b) Beginning when the headway corresponds to L0, the 
subject vehicle speed is maintained within 1.6 km/h of the test speed 
with minimal and smooth accelerator pedal inputs.
    (c) Beginning when the headway corresponds to L0, the 
subject vehicle heading is maintained with minimal steering input such 
that the travel path does not deviate more than 0.3 m laterally from 
the intended travel path, and the yaw rate of the subject vehicle does 
not exceed 1.0 deg/s.
    (d) If forward collision warning occurs, the subject vehicle's 
accelerator pedal is released at any rate such that it is fully 
released within 500 ms. This action is omitted for vehicles with cruise 
control active.
    (e) For tests where no manual brake application occurs, manual 
braking is not applied until the test completion criteria of S8.2.3 are 
satisfied.
    (f) For tests where manual brake application occurs, the subject 
vehicle's accelerator pedal, if not already released, is released when 
the headway corresponds to L2.1 at any rate such that it is 
fully released within 500 ms.
    (g) For tests where manual brake application occurs, the service 
brakes are applied as specified in S9. The brake application pedal 
onset occurs at headway L1.1.
    S8.2.3. Test completion criteria. The test run is complete when the 
subject vehicle comes to a stop prior to crossing over the leading edge 
of the steel trench plate or when the subject vehicle crosses over the 
leading edge of the steel trench plate.
    S8.3. Pass-through.
    S8.3.1. Test parameters and setup.
    (a) The testing area is set up in accordance with Figure 3 to this 
section.
    (b) Two vehicle test devices are secured in a stationary position 
parallel to one another with a lateral distance of 4.5 m 0.1 m between the vehicles' closest front wheels. The centerline 
between the two vehicles is parallel to the intended travel path.
    (c) The subject vehicle test speed is 80 km/h.
    (d) Testing may be conducted with manual subject vehicle pedal 
application.
    S8.3.2. Test conduct.
    (a) The subject vehicle approaches the gap between the two vehicle 
test devices.
    (b) Beginning when the headway corresponds to L0, the 
subject vehicle speed is maintained within 1.6 km/h with minimal and 
smooth accelerator pedal inputs.
    (c) Beginning when the headway corresponds to L0, the 
subject vehicle heading is maintained with minimal steering input such 
that the travel path does not deviate more than 0.3 m laterally from 
the intended travel path, and the yaw rate of the subject vehicle does 
not exceed 1.0 deg/s.
    (d) If forward collision warning occurs, the subject vehicle's 
accelerator pedal is released at any rate such that it is fully 
released within 500 ms.
    (e) For tests where no manual brake application occurs, manual 
braking is not applied until the test completion criteria of S8.3.3 are 
satisfied.
    (f) For tests where manual brake application occurs, the subject 
vehicle's accelerator pedal, if not already released, is released when 
the headway corresponds to L2.1 at any rate such that it is 
fully released within 500 ms.
    (g) For tests where manual brake application occurs, the service 
brakes are applied as specified in S9. The brake application onset 
occurs when the headway corresponds to L1.1.
    S8.3.3. Test completion criteria. The test run is complete when the 
subject vehicle comes to a stop prior to its rearmost point passing the 
vertical plane connecting the forwardmost point of the vehicle test 
devices or when the rearmost point of the subject vehicle passes the 
vertical plane connecting the forwardmost point of the vehicle test 
devices.
    S9. Subject Vehicle Brake Application Procedure.
    S9.1. The procedure begins with the subject vehicle brake pedal in 
its natural resting position with no preload or position offset.
    S9.2. At the option of the manufacturer, either displacement 
feedback or hybrid feedback control is used.
    S9.3. Displacement feedback procedure. For displacement feedback, 
the commanded brake pedal position is the brake pedal position that 
results in a mean deceleration of 0.3g in the absence of AEB system 
activation.
    (a) The mean deceleration is the deceleration over the time from 
the pedal achieving the commanded position to 250 ms before the vehicle 
comes to a stop.
    (b) The pedal displacement controller depresses the pedal at a rate 
of 254 mm/s 25.4 mm/s to the commanded brake pedal 
position.
    (c) The pedal displacement controller may overshoot the commanded 
position by any amount up to 20 percent. If such an overshoot occurs, 
it is corrected within 100 ms.
    (d) The achieved brake pedal position is any position within 10 
percent of the commanded position from 100 ms after pedal displacement 
occurs and any overshoot is corrected.
    S9.4. Hybrid brake pedal feedback procedure. For hybrid brake pedal 
feedback, the commanded brake pedal application is the brake pedal 
position and a subsequent commanded brake pedal force that results in a 
mean deceleration of 0.3g in the absence of AEB system activation.
    (a) The mean deceleration is the deceleration over the time from 
the pedal achieving the commanded position to 250 ms before the vehicle 
comes to a stop.
    (b) The hybrid controller displaces the pedal at a rate of 254 mm/s 
25.4 mm/s to the commanded pedal position.
    (c) The hybrid controller may overshoot the commanded position by 
any amount up to 20 percent. If such an overshoot occurs, it is 
corrected within 100 ms.
    (d) The hybrid controller begins to control the force applied to 
the pedal and stops controlling pedal displacement 100 ms after pedal 
displacement occurs and any overshoot is corrected.
    (e) The hybrid controller applies a pedal force of at least 11.1 N.
    (f) The applied pedal force is maintained within 10 percent of the 
commanded brake pedal force from 350 ms after commended pedal 
displacement occurs and any overshoot is corrected until test 
completion.

[[Page 43244]]

Figure 1 to Sec.  571.128--Setup for Tests Approaching a Lead Vehicle

BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TP06JY23.010

Figure 2 to Sec.  571.128--Setup for Steel Trench Plate False 
Activation Tests
[GRAPHIC] [TIFF OMITTED] TP06JY23.011

Figure 3 to Sec.  571.128--Setup for Pass-Through False Activation 
Tests

[[Page 43245]]

[GRAPHIC] [TIFF OMITTED] TP06JY23.012

BILLING CODE 4910-59-C
0
9. Amend Sec.  571.136 by revising paragraphs S3, S3.1, S3.2, and 
paragraphs (1) and (2) of the definition of ``Electronic stability 
control system or ESC system'' in S4, and adding S8.3 to read as 
follows:


Sec.  571.136   Standard No. 136; Electronic stability control systems 
for heavy vehicles.

* * * * *
    S3 Application.
    S3.1 This standard applies to passenger cars, multipurpose 
passenger vehicles, trucks, and buses, with a GVWR greater than 4,536 
kilograms (10,000 pounds) except:
    (a) Any vehicle equipped with an axle that has a gross axle weight 
rating of 13,154 kilograms (29,000 pounds) or more;
    (b) Any truck or bus that has a speed attainable in 3.2 kilometers 
(2 miles) of not more than 53 km/h (33 mph); and
    (c) Any truck that has a speed attainable in 3.2 kilometers (2 
miles) of not more than 72 km/h (45 mph), an unloaded vehicle weight 
that is not less than 95 percent of its gross vehicle weight rating, 
and no capacity to carry occupants other than the driver and operating 
crew.
    S3.2 The following vehicles are subject only to the requirements in 
S5.1, S5.2, and S5.4 of this standard:
    (a) Vehicles with a gross vehicle weight rating of 11,793 kilograms 
(26,000 pounds) or less;
    (b) Trucks other than truck tractors;
    (c) School buses;
    (d) Perimeter-seating buses;
    (e) Transit buses;
    (f) Passenger cars; and
    (g) Multipurpose passenger vehicles.
* * * * *
    S4 Definitions
* * * * *
    Electronic stability control system or ESC system means a system 
that has all of the following attributes:
    (1) It augments vehicle directional stability by having the means 
to apply and adjust the vehicle brake torques individually at each 
wheel position on at least one front and at least one rear axle of the 
vehicle to induce correcting yaw moment to limit vehicle oversteer and 
to limit vehicle understeer;
    (2) It enhances rollover stability by having the means to apply and 
adjust the vehicle brake torques individually at each wheel position on 
at least one front and at least one rear axle of the vehicle to reduce 
lateral acceleration of a vehicle;
* * * * *
    S8.3 Vehicles with a gross vehicle weight rating of 11,793 
kilograms (26,000 pounds) or less, trucks other than truck tractors, 
school buses, perimeter-seating buses, transit buses, passenger cars, 
and multipurpose passenger vehicles are not required to comply this 
standard before [the first September 1 that is four years after the 
date of publication of a final rule].
* * * * *
0
11. Add part 596 to read as follows.

PART 596--AUTOMATIC EMERGENCY BRAKING TEST DEVICES

Subpart A--General

Sec.
596.1 Scope.
596.2 Purpose.
596.3 Application
596.4 Definitions.
596.5 Matter incorporated by reference.
Subpart B--[Reserved]
Subpart C--Vehicle Test Device
596.9 General Description
596.10 Specifications for the Vehicle Test Device

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

Subpart A--General


Sec.  596.1  Scope.

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


Sec.  596.2  Purpose.

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


Sec.  596.3  Application.

    This part does not in itself impose duties or liabilities on any 
person. It is a description of tools that are used in compliance tests 
to measure the performance of automatic emergency braking systems 
required by the safety standards that refer to these tools. This part 
is designed to be referenced by, and become part of, the test 
procedures specified in motor vehicle safety standards.


Sec.  596.4  Definitions.

    All terms defined in section 30102 of the National Traffic and 
Motor Vehicle Safety Act (49 U.S.C. chapter 301, et seq.) are used in 
their statutory meaning.
    Vehicle Test Device means a test device that simulates a passenger 
vehicle for the purpose of testing automatic emergency brake system 
performance.
    Vehicle Test Device Carrier means a movable platform on which a 
Lead Vehicle Test Device may be attached during compliance testing.

[[Page 43246]]

Sec.  596.5  Matter incorporated by reference.

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

Subpart B--[Reserved]

Subpart C--Vehicle Test Device


Sec.  596.9  General Description.

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


Sec.  596.10   Specifications for the Vehicle Test Device.

    (a) Word Usage--Recommendations. The words ``recommended,'' 
``should,'' ``can be,'' or ``should be'' appearing in sections of ISO 
19206-3:2021(E) (incorporated by reference, see Sec.  596.5), 
referenced in this section, are read as setting forth specifications 
that are used.
    (b) Word Usage--Options. The words ``may be,'' or ``either,'' used 
in connection with a set of items appearing in sections of ISO 19206-
3:2021(E) (incorporated by reference, see Sec.  596.5), referenced in 
this section, are read as setting forth the totality of items, any one 
of which may be selected by NHTSA for testing.
    (c) Dimensional specifications. (1) The rear silhouette and the 
rear window are symmetrical about a shared vertical centerline.
    (2) Representations of the taillamps, rear reflex reflectors, and 
tires are symmetrical about the surrogate's centerline.
    (3) The license plate representation has a width of 300  15 mm and a height of 150  15 mm and mounted with a 
license plate holder angle within the range described in 49 CFR 571.108 
S6.6.3.1.
    (4) The Vehicle Test Device representations are located within the 
minimum and maximum measurement values specified in columns 3 and 4 of 
Tables A.4 of ISO 19206-3:2021(E) Annex A (incorporated by reference, 
see Sec.  596.5). The tire representations are located within the 
minimum and maximum measurement values specified in columns 3 and 4 of 
Tables A.3 of ISO 19206-3:2021(E) Annex A (incorporated by reference, 
see Sec.  596.5). The terms ``rear light'' means ``taillamp,'' 
``retroreflector'' means ``reflex reflector,'' and ``high centre 
taillight'' means ``high-mounted stop lamp.''
    (d) Visual and near infrared specification. (1) The Vehicle Test 
Device rear representation colors are within the ranges specified in 
Tables B.2 and B.3 of ISO 19206-3:2021(E) Annex B (incorporated by 
reference, see Sec.  596.5).
    (2) The rear representation infrared properties of the Vehicle Test 
Device are within the ranges specified in Table B.1 of ISO 19206-
3:2021(E) Annex B (incorporated by reference, see Sec.  596.5) for 
wavelengths of 850 to 950 nm when measured according to the calibration 
and measurement setup specified in paragraph B.3 of ISO 19206-3:2021(E) 
Annex B (incorporated by reference, see Sec.  596.5).
    (3) The Vehicle Test Device rear reflex reflectors, and at least 50 
cm\2\ of the taillamp representations are grade DOT-C2 reflective 
sheeting as specified in 49 CFR 571.108 S8.2.
    (e) Radar reflectivity specifications. (1) The radar cross section 
of the Vehicle Test Device is measured with it attached to the carrier 
(robotic platform). The radar reflectivity of the carrier platform is 
less than 0 dBm\2\ for a viewing angle of 180 degrees and over a range 
of 5 to 100 m when measured according to the radar measurement 
procedure specified in C.3 of ISO 19206-3:2021(E) Annex C (incorporated 
by reference, see Sec.  596.5) for fixed-angle scans.
    (2) The rear bumper area as shown in Table C.1 of ISO 19206-
3:2021(E) Annex C (incorporated by reference, see Sec.  596.5) 
contributes to the target radar cross section.
    (3) The radar cross section is assessed using radar sensor that 
operates at 76 to 81 GHz and has a range of at least 5 to 100 m, a 
range gate length smaller than 0.6m, a horizontal field of view of 10 
degrees or more (-3dB amplitude limit), and an elevation field of view 
of 5 degrees or more (-3dB amplitude).
    (4) At least 92 percent of the filtered data points of the 
surrogate radar cross section for the fixed vehicle angle, variable 
range measurements are within the RCS boundaries defined in Sections 
C.2.2.4 of ISO 19206-3:2021(E) Annex C (incorporated by reference, see 
Sec.  596.5) for a viewing angle of 180 degrees when measured according 
to the radar measurement procedure specified in C.3 of ISO 19206-
3:2021(E) Annex C (incorporated by reference, see Sec.  596.5) for 
fixed-angle scans.
    (5) Between 86 to 95 percent of the Vehicle Test Device spatial 
radar cross section reflective power is with the primary reflection 
region defined in Section C.2.2.5 of ISO 19206-3:2021(E) Annex C 
(incorporated by reference, see Sec.  596.5) when measured according to 
the radar measurement procedure specified in C.3 of ISO 19206-3:2021(E) 
Annex C (incorporated by reference, see Sec.  596.5) using the angle-
penetration method.

    Issued under the authority delegated in 49 CFR 1.87.
Robin Hutcheson,
Administrator.
    Issued under authority delegated in 49 CFR part 1.95 and 49 CFR 
501.8.
Raymond R. Posten,
Associate Administrator for Rulemaking.
[FR Doc. 2023-13622 Filed 7-5-23; 8:45 am]
BILLING CODE 4910-59-P