Document ID: NHTSA-2023-0032-0001
Agency: nhtsa
Document Type: Proposed Rule
Title: Federal Motor Vehicle Safety Standards: Occupant Crash Protection, Seat Belt Reminder Systems
Posted Date: 2023-09-07T04:00Z

[Federal Register Volume 88, Number 172 (Thursday, September 7, 2023)]
[Proposed Rules]
[Pages 61674-61743]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-18413]

[[Page 61673]]

Vol. 88

Thursday,

No. 172

September 7, 2023

Part II

Department of Transportation

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National Highway Traffic Safety Administration

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49 CFR Part 571

Federal Motor Vehicle Safety Standards; Occupant Crash Protection, Seat 
Belt Reminder Systems; Proposed Rule

  Federal Register / Vol. 88 , No. 172 / Thursday, September 7, 2023 / 
Proposed Rules  

[[Page 61674]]

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. NHTSA-2023-0032]
RIN 2127-AL37

Federal Motor Vehicle Safety Standards; Occupant Crash 
Protection, Seat Belt Reminder Systems

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

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The Moving Ahead for Progress in the 21st Century Act of 2012 
(MAP-21) directs NHTSA to initiate a rulemaking proceeding to amend 
Federal Motor Vehicle Safety Standard (FMVSS) No. 208, ``Occupant crash 
protection,'' to require a seat belt use warning system for rear seats. 
Pursuant to this mandate and following on an earlier Advance Notice of 
Proposed Rulemaking, NHTSA is proposing to require a seat belt warning 
system for the rear seats of passenger cars, trucks, most buses, and 
multipurpose passenger vehicles with a gross vehicle weight rating of 
4,536 kilograms (10,000 pounds) or less. This document also proposes to 
enhance the existing front seat belt warning requirements, including 
requiring a seat belt warning for the front outboard passenger seat and 
increasing the duration of the warning.

DATES: You should submit your comments early enough to be received not 
later than November 6, 2023. In compliance with the Paperwork Reduction 
Act, NHTSA is also seeking comment on a revision to an existing 
information collection. For additional information, see the Paperwork 
Reduction Act section under the Regulatory Notices and Analyses section 
below. All comments relating to the information collection requirements 
should be submitted to NHTSA and to the Office of Management and Budget 
(OMB) at the address listed in the ADDRESSES section on or before 
November 6, 2023.

DATES: Proposed effective date: The first September 1 that is one year 
after the publication of the final rule for the front seat belt warning 
system requirements and the first September 1 that is two years after 
the publication of the final rule for the rear seat belt warning system 
requirements, with optional early compliance permitted. Multi-stage 
manufacturers and alterers would have an additional year to comply.

ADDRESSES: You may submit comments electronically to the docket 
identified in the heading of this document by visiting the Federal 
eRulemaking Portal at https://www.regulations.gov. Follow the online 
instructions for submitting comments.
    Alternatively, you can file comments using the following methods:
     Mail: Docket Management Facility: U.S. Department of 
Transportation, 1200 New Jersey Avenue SE, West Building Ground Floor, 
Room W12-140, Washington, DC 20590-0001.
     Hand Delivery or Courier: West Building Ground Floor, Room 
W12-140, 1200 New Jersey Avenue SE, between 9 a.m. and 5 p.m. ET, 
Monday through Friday, except Federal holidays. To be sure someone is 
there to help you, please call (202) 366-9826 before coming.
     Fax: (202) 493-2251.
    Regardless of how you submit your comments, you should mention the 
docket number identified in the heading of this document.
    Comments on the proposed information collection requirements should 
be submitted to: Office of Management and Budget at www.reginfo.gov/public/do/PRAMain. To find this particular information collection, 
select ``Currently under Review--Open for Public Comment'' or use the 
search function. It is requested that comments sent to the OMB also be 
sent to the NHTSA rulemaking docket identified in the heading of this 
document.
    Instructions: All submissions must include the agency name and 
docket number or Regulatory Information Number (RIN) for this 
rulemaking. 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. Please see the Privacy Act heading below.
    Docket: For access to the docket to read background documents or 
comments received, go to https://www.regulations.gov. You may also 
access the docket at 1200 New Jersey Avenue SE, West Building, Room 
W12-140, Washington, DC 20590, between 9 a.m. and 5 p.m., Monday 
through Friday, except Federal Holidays. Telephone: 202-366-9826.
    Confidential Business Information: If you claim that any of the 
information in your comment (including any additional documents or 
attachments) constitutes confidential business information within the 
meaning of 5 U.S.C. 552(b)(4) or is protected from disclosure pursuant 
to 18 U.S.C. 1905, please see the detailed instructions given under the 
Public Participation heading of the SUPPLEMENTARY INFORMATION section 
of this document.
    Privacy Act: Please see the Privacy Act heading under the 
Regulatory Analyses section of this document.

FOR FURTHER INFORMATION CONTACT: For non-legal issues, you may contact 
Ms. Carla Rush, Office of Crashworthiness Standards, Telephone: (202) 
366-4583; Email: [email protected]; Facsimile: (202) 493-2739. For 
legal issues, you may contact Mr. John Piazza, Office of Chief Counsel, 
Telephone: (202) 366-2992; Email: [email protected]; Facsimile: (202) 
366-3820. The address of these officials is: the National Highway 
Traffic Safety Administration, 1200 New Jersey Avenue SE, Washington, 
DC 20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary
II. Background
III. Regulatory and Legislative History
IV. ECE Requirements and Euro NCAP
V. NHTSA Research on Effectiveness and Acceptance of Seat Belt 
Warning Systems
VI. Safety Need
VII. ANPRM
VIII. NHTSA's Statutory Authority
IX. Overview of Proposed Requirements
X. Proposed Rear Seat Belt Warning
    A. Overview
    B. Applicability
    C. Requirements
    1. Visual Warning on Vehicle Start-Up
    a. Compliance Options for the Type of Information Conveyed
    b. Triggering Conditions
    c. Seat Occupancy Criteria and Interaction With Child Restraint 
Systems
    d. Minimum Duration
    2. Audio-Visual Change-of-Status Warning
    3. Telltale Location
    4. Telltale Characteristics
    5. Belt Use Criteria
    6. Electrical Connections
    7. Owner's Manual Instructions
    8. Interaction With Other Vehicle Warnings
    D. Alternative Warning Signals
    E. Resistance to Intentional and Inadvertent Defeat and 
Deactivation
    F. Consumer Acceptance
    G. Technological and Economic Feasibility
XI. Warning Requirements for Front Outboard Seats
    A. Seat Belt Warning for Front Outboard Passenger Seat
    B. Driver's Seat Belt Warning for Medium-Sized Buses

[[Page 61675]]

    C. Amendments to the Current Warning Signal Requirements
    1. Increasing the Duration of the Audio-Visual Warning on 
Vehicle Start-Up
    2. Requiring an Audio-Visual Change-of-Status Warning
    3. Audible Warning Characteristics
    4. Visual Warning Characteristics
    5. Other Warning Signal Features and Criteria
XII. Other issues
    A. Automatic Belts
    B. Test Procedures
    C. Considerations for Automated Driving Systems
XIII. Regulatory Alternatives
    A. ECE R16 and Euro NCAP
    B. Occupant Detection and Enhanced Warning Signals for the Rear 
Seat Belt Warning
    C. Non-Regulatory Alternatives
    D. Requiring a Warning System for the Front Center Seat
    E. Requiring a 90 Second Duration Seat Belt Warning System for 
the Front Outboard Seating Positions
XIV. Overview of Benefits and Costs
    A. Proposed Requirements
    1. Rear Seat Belt Warning System
    2. Front Seat Belt Warning System
    3. Overall Benefits and Costs of Proposal
    B. Regulatory Alternatives
    1. Occupant Detection in Rear Seats
    2. 90-Second Front Outboard Seat Belt Warning
    3. Seat Belt Warning for Front Center Seat
XV. Proposed Effective Date
XVI. Regulatory Analyses
XVII. Public Participation
Appendix A--Front Outboard Seat Belt Warnings--Additional Data
Proposed Regulatory Text

I. Executive Summary

    In 2020, there were 39,007 motor vehicle traffic fatalities in the 
United States.\1\ This was 2,652 more fatalities than in 2019 (when 
there were 36,355 fatalities).\2\ In 2021, motor vehicle traffic 
fatalities increased again to 42,939.\3\ The traffic fatality count in 
2021 is the highest since 2005 (43,510) and represents the second year-
to-year increase since 2019.\4\ The 10-percent fatality increase from 
2020 to 2021 is the highest year-to-year percentage increase since FARS 
started data collection in 1975.\5\ NHTSA has preliminarily estimated 
42,795 fatalities in 2022, representing a small decrease of about 0.3% 
from 2021.\6\ The Moving Ahead for Progress in the 21st Century Act 
(MAP-21) directed NHTSA to initiate a rulemaking to require a seat belt 
warning for the rear seats in motor vehicles. In addition, the 
Department of Transportation has released a comprehensive National 
Roadway Safety Strategy to address the rise in roadway fatalities and 
injuries. Part of that strategy is to make vehicles safer.
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    \1\ Stewart, T. (April 2023). Overview of Motor Vehicle Traffic 
Crashes in 2021 (Report NO. DOT HS 813 435. National Highway Traffic 
Safety Administration, pg. 5.
    \2\ Id. at pg. 2.
    \3\ Id. at pg. 5.
    \4\ Id.
    \5\ Id. The 2021 fatality estimates are not entirely final, and 
may change somewhat as NHTSA receives further updates or 
corrections.
    \6\ See https://www.transportation.gov/briefing-room/nhtsa-estimates-2022-show-roadway-fatalities-remain-flat-after-two-years-dramatic. Though NHTSA acknowledges fatalities essentially remained 
flat in 2022, NHTSA does not know if this trend will continue to 
remain flat or if there will be further increases in fatalities.
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    Consistent with MAP-21 and the National Roadway Safety Strategy, 
this NPRM proposes to require a seat belt use warning system \7\ for 
the rear seats of passenger cars, trucks, buses (except school buses, 
for various reasons detailed in the Applicability section of the 
preamble, including practicability and cost concerns), and multipurpose 
passenger vehicles (MPVs) with a GVWR of 4,536 kg (10,000 lb) or less. 
This NPRM also proposes several changes and enhancements to the 
existing front seat belt warning requirements, including increasing the 
duration of the audio-visual seat belt warning on vehicle start-up.
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    \7\ Seat belt use warning systems may also be referred to in 
this preamble as seat belt ``warning systems'' (or SBWS) or seat 
belt ``reminder'' systems (or SBRSs).
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Safety Need for the Proposed Rule

    Using a seat belt is one of the most effective actions a motor 
vehicle occupant can take to prevent death and injury in a crash. Seat 
belts prevent occupants from being ejected from the vehicle, provide 
``ride-down'' by gradually decelerating the occupant as the vehicle 
deforms and absorbs energy, and reduce the occurrence of occupant 
contact with harmful interior surfaces and other occupants. Seat belts 
are effective in most types of crashes, and greatly reduce the risk of 
fatal and non-fatal injuries compared to the risk faced by unrestrained 
occupants.
    While seat belt use is meaningfully higher than it was a decade 
ago, there is room for improvement. Usage rates for seat belts in rear 
seats have consistently been below those for the front seats, and while 
front seat belt use rates increased early in the previous decade, for 
the last several years they have plateaued. According to data from 
NHTSA's annual study of observed seat belt use, from 2012 to 2021, seat 
belt use was lower in the rear seat than in the front seat, ranging 
from a difference of about 9 percent in 2013 (78% vs. 87%) to about 14 
percent in 2017 (75% vs. 89%).\8\ During that time, front seat belt use 
rates ranged from about 86% in 2012 to 91% in 2019. In 2021, front seat 
belt use was about 90%, and rear seat belt use was about 78%. 
Accordingly, every year, thousands of unrestrained motor vehicle 
occupants are killed in crashes, and tens of thousands of unrestrained 
occupants are injured (additional details on the target population are 
provided in the summary of benefits and costs later in this executive 
summary).
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    \8\ Boyle, L.L. (2022, August). Occupant restraint use in 2021: 
Results from the NOPUS Controlled Intersection Study (Report No. DOT 
HS 813 344). National Highway Traffic Safety Administration.
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    Many of these unbelted occupants are likely amenable to using a 
seat belt. Seat belt nonusers can be categorized as either ``part-
time'' nonusers or so-called ``hard-core'' nonusers. Part-time nonusers 
generally express positive attitudes toward seat belts, but do not 
always buckle up, due to a range of reasons, such as short trips, 
forgetfulness, and being in a rush. Hard-core nonusers are those who 
generally do not acknowledge the benefits of seat belts and are opposed 
to their use. Consumer research suggests that most nonusers are part-
time nonusers, not hard-core nonusers. This is true even for front seat 
occupants, for which there is a relatively high rate of observed seat 
belt use. For instance, NHTSA's most recent survey of seat belt use 
found that approximately 83% of drivers who did not always use a seat 
belt reported using a seat belt most or some of the time, and only 17% 
were hard-core nonusers who used seat belts rarely or never.\9\ The 
same is true for rear seat passengers who do not always use a belt, of 
whom 70% used a belt most or some of the time, while only 30% used a 
belt rarely or never.
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    \9\ 2016 MVOSS, p.7 (calculated from Fig. 5).
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    Seat belt warning systems encourage seat belt use by reminding 
unbuckled occupants to fasten their belts and/or by informing the 
driver that a passenger is unbelted so that the driver can request the 
unbelted occupant to buckle up. The warnings provided by seat belt 
warning systems typically consist of visual and/or audible signals. 
Research by NHTSA and others shows that seat belt warning systems are 
effective at getting unbuckled occupants to fasten their seat belt.\10\
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    \10\ This research is identified and discussed in Section V and 
Section XIV.A, as well as the Preliminary Regulatory Impact Analysis 
docketed with this NPRM.
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    Federal Motor Vehicle Safety Standard (FMVSS) No. 208, ``Occupant 
crash protection,'' requires a short-duration audio-visual seat belt 
warning for the driver's seat belt on passenger cars, most trucks and 
MPVs with a GVWR of 4,536 kg (10,000 lb) or less,

[[Page 61676]]

and buses with a GVWR of 3,855 kg (8,500 lb) or less. According to the 
FMVSS No. 208 standard, the visual component of the warning generally 
must be at least sixty seconds long, and the audible component must be 
at least four seconds long.
    In general, voluntary adoption of warnings that go beyond this 
regulatory minimum, while considerable, has been mixed. Although the 
regulations do not require seat belt warnings for any seating position 
other than the driver's seat, almost all model year (MY) 2022 vehicles 
have a voluntarily-provided seat belt warning for the front outboard 
passenger seat. However, voluntary adoption for rear seats has been 
much slower, as only about 47% come equipped with a voluntarily-
provided rear seat belt warning system (SBWS). Most vehicles already 
provide a seat belt warning for both front outboard seats that is much 
longer than the minimal required warning for the driver's seat belt, 
with the vast majority of vehicles including an alert that is at least 
90 seconds. This suggests that the front seat belt warning minimum 
requirements in the FMVSS are outdated, as consumers seem clearly 
willing to accept audio-visual reminders that are far longer than the 
required four seconds.
    In short, rear seat belt use rates have persistently been below 
those for the front seats, and progress on front seat belt use rates 
have slowed. Moreover, unbuckled occupants, in the front and rear 
seats, continue to be overrepresented in fatal crashes (51%), given the 
lower exposure of unbelted occupants relative to belted occupants 
(because front seat belt use was about 90% and rear seat belt use was 
80%). Nevertheless, in spite of the effectiveness of seat belts and 
seat belt warnings, most new vehicles continue to lack a rear seat belt 
warning. Additionally, while most vehicles provide some level of 
enhanced reminders for the front seats, this level of enhanced 
protection has not occurred for all vehicles and is not standardized. 
This suggests a need for a beneficial safety technology that is not 
being met in the vehicle market. This NPRM is intended to meet this 
safety need and advance NHTSA's response to MAP-21.

Legal Authority and Prior Regulatory History

    This proposal is issued pursuant to NHTSA's authority under the 
National Traffic and Motor Vehicle Safety Act (49 U.S.C. 30101 et seq.) 
(Safety Act), which authorizes NHTSA to establish Federal Motor Vehicle 
Safety Standards. The statute requires safety standards to be 
objective, practicable, and meet the need for safety, among other 
things. NHTSA has tentatively concluded that the proposed requirements 
satisfy these statutory criteria.
    This NPRM also continues NHTSA's response to a rulemaking mandate 
in MAP-21. MAP-21 required DOT (NHTSA, by delegation) to initiate a 
rulemaking proceeding to require rear seat belt warnings and directed 
the agency to issue a final rule unless the rule would not meet the 
Safety Act requirements for an FMVSS. In accordance with MAP-21, in 
2013 NHTSA initiated a rulemaking proceeding when it submitted for 
public comment a proposal to undertake a study of the effectiveness of 
existing rear seat belt warning systems. In 2019, NHTSA continued with 
this rulemaking proceeding by publishing an Advance Notice of Proposed 
Rulemaking (ANPRM) seeking comment on a variety of issues related to 
potential rear seat belt warning requirements. NHTSA received 45 
comments from a variety of organizations and individuals. Most 
commenters, including safety advocates, vehicle manufacturers and 
suppliers, and individual members of the public, supported a rear seat 
belt warning requirement.
    This NPRM also responds to a rulemaking petition. Public Citizen 
and Advocates for Highway and Auto Safety have petitioned NHTSA to 
require a seat belt warning system for rear seats on passenger cars and 
MPVs with a GVWR of 4,536 kg (10,000 lb) or less. This proposal is 
NHTSA's further action on its grant of this petition.

Summary of the Proposed Amendments

    This NPRM proposes amending the existing seat belt warning 
provisions in FMVSS No. 208. This proposal has two main components. The 
first proposes requiring a rear seat belt reminder for the rear seats. 
The second proposes changes and enhancements to the seat belt warning 
requirements for the front outboard seats, most notably an audio-visual 
warning that persists until the seat belts at any occupied front 
outboard seat are fastened. These proposed requirements would apply to 
passenger cars and trucks, buses (except school buses), and 
multipurpose passenger vehicles with a GVWR of 4,536 kg (10,000 lb) or 
less.
1. Rear Seat Belt Reminder Requirements
    The first component of this NPRM is a set of proposed requirements 
for a seat belt warning for rear seats. The proposed requirements have 
four main elements.
     Visual warning on vehicle start-up to inform the driver of 
the status of the rear seat belts. We propose three different 
compliance options from which manufacturers could choose for the rear 
seat belt warning system. The first would require the system to 
indicate how many or which rear seat belts are in use (the ``positive-
only'' option). The second would require the system to indicate, for 
the occupied rear seats, how many or which rear seat belts are not in 
use (the ``negative-only'' option). The third would require the system 
to indicate, for the occupied rear seats, how many or which rear seat 
belts are in use and how many or which rear seat belts are not in use 
(the ``full-status'' option). Certain features would be required of all 
the options. Each system would have to provide a continuous or flashing 
visual warning, consisting of either icons or text, visible to the 
driver. The visual warning would have to last for at least 60 seconds, 
beginning when the vehicle's ignition switch is moved to the ``on'' or 
``start'' position. The negative-only and full-status compliance 
options would require that the rear seats be equipped with a belt latch 
sensor and an occupant detection system (which facilitates these more 
informative warnings), while the positive-only option would only 
require that the rear seats be equipped with a belt latch sensor.
     Audio-visual change-of-status warning. We propose an 
audio-visual warning whenever a fastened rear seat belt is unfastened 
while the ignition switch is in the ``on'' or ``start'' position and 
the vehicle's transmission selector is in a forward or reverse gear. 
The warning would have to last for at least 30 seconds. We do not 
propose any requirements for the volume or tone of the warning. The 
intent of this warning is to alert the driver or other occupants to a 
change in belt status during a trip. The warning would not be required 
if a door is open, which would be the case if a rear passenger 
unfastened their belt in order to exit the vehicle.
     Requirements related to electrical connections. Readily 
removable rear seats would be required to either automatically connect 
to the electrical connections when the seat is put in place, or, if a 
manual connection is required, the connectors must be readily-
accessible. Further, vehicles utilizing the negative-only compliance 
option would be required to provide a visual warning to the driver if a 
proper electrical connection has not been established for a readily 
removable rear seat.
     Owner's manual requirements. We propose that the vehicle 
owner's manual

[[Page 61677]]

(which includes information provided by the vehicle manufacturer to the 
consumer, whether in digital or printed form) describe the warning 
system's features, including the location and format of the visual 
warnings. We also propose that the owner's manual include instructions 
on how to make any manual electrical connections for readily removable 
seats.
2. Front Outboard Seat Belt Warning Requirements
    We propose several changes and enhancements to the seat belt 
warning requirements for the front outboard seats. There are three main 
changes we are proposing.
     Audio-visual warning on vehicle start-up for front 
outboard passenger seat. Currently, only the driver's seat is required 
to have a seat belt warning, although almost all vehicles now provide a 
seat belt warning for the front outboard passenger seat as well.\11\ We 
propose to require a seat belt warning for the front outboard passenger 
seat.
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    \11\ Based on data on total projected vehicle sales in the 
United States for model year 2022 from the agency's New Car 
Assessment Program Purchasing with Safety in Mind: What to Look For 
When Buying a Vehicle program.
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     Increasing the duration of the audio-visual warning on 
vehicle start-up. We propose enhancing the front seat warning 
requirements by requiring an audio-visual warning that remains active 
until the seat belt at any occupied front outboard seat is fastened. We 
are proposing this in light of a variety of factors, including the 
increase in roadway fatalities, the lack of improvement in front seat 
belt use rates, and the fact that the audio-visual warnings with which 
vehicle manufacturers are currently equipping vehicles significantly 
exceed the 4-second regulatory minimum (including a non-trivial share 
of currently sold vehicles with an indefinite-duration reminder). 
Vehicle manufacturers can adjust warning signal characteristics (such 
as frequency and volume) to make the warning both effective and 
acceptable to consumers.
     Audio-visual change-of-status warning. We also propose to 
require an audio-visual change-of-status warning whenever a front 
outboard seat belt is unbuckled during a trip (unless a front door is 
open, to account for an occupant unfastening the belt to exit the 
vehicle). The warning would be required to remain active until the seat 
belt is refastened.

Proposed Effective Date

    We propose an effective date of the first September 1 that is one 
year after the publication of the final rule for the front seat belt 
warning system requirements and the first September 1 that is two years 
after the publication of the final rule for the rear seat belt warning 
system requirements, with optional early compliance (See Section XV for 
details). Consistent with 49 CFR 571.8(b), multi-stage manufacturers 
and alterers would have an additional year to comply.

Regulatory Alternatives

    NHTSA considered a wide range of alternatives to the proposed 
requirements. The main alternatives NHTSA considered were the seat belt 
warning requirements in Economic Commission for Europe (ECE) Regulation 
R16 and Euro New Car Assessment Programme (NCAP). The proposed 
requirements are identical or similar to ECE R16 and Euro NCAP in many 
respects but differ from them in several ways. For instance, while the 
ECE rear seat belt warning regulations allow a warning for an 
unfastened seat belt at an unoccupied seat, this proposal would not 
allow this, because we tentatively believe that the resulting ``false'' 
warning would potentially annoy drivers and lead to behaviors that 
would decrease system effectiveness. Another way the proposal differs 
from ECE R16 is the duration of the front seat belt warning on vehicle 
start-up: R16 generally requires only a 30-60 second audio-visual 
warning; we propose a warning that lasts until the seat belt is 
buckled. The regulatory analysis quantifies the costs and benefits of 
three specific regulatory alternatives: requiring occupant detection 
for the rear seat belt warning system; requiring (for the front 
outboard seats) an audio-visual warning on vehicle start-up with a 
duration of 90 seconds; and requiring a seat belt warning for front 
center seats.

Benefits and Costs of the Proposed Requirements

    NHTSA estimates the target population and the benefits and costs of 
the proposed requirements in the stand-alone preliminary regulatory 
impact analysis (PRIA) that is being placed in the docket with this 
NPRM and is summarized in the NPRM.
    Based on NHTSA's data on fatalities and injuries from motor vehicle 
crashes, adjusted to account for the benefits of other mandatory safety 
technologies, there are, on average, 475 fatalities and 7,036 injuries 
to unrestrained rear seat occupants and 6,733 fatalities and 47,952 
injuries to unrestrained front outboard seat occupants each year. This 
is the overall target population--the annual deaths and injuries that 
the proposed requirements are aimed at reducing.
    NHTSA estimates the benefits it expects from the proposed seat belt 
warning requirements. The benefits are the fatalities and injuries that 
would be prevented by these proposed requirements. The benefits depend, 
principally, on the expected increase in seat belt use and the 
effectiveness of seat belts in preventing deaths and injuries.
    For the rear seat belt warning system analysis, NHTSA used a 
``low'' and a ``high'' estimate for the increase in rear belt use with 
the proposed warning system. For occupants 11 years and older, these 
were 3 and 5 percentage points, and for occupants from 6 to 10 years 
old, 0.3 and 0.4 percentage points.\12\ For simplicity, NHTSA refers to 
these scenarios as ``Low'' and ``High,'' or ``3%'' and ``5%.'' The 
estimated annual benefits are presented in table 1.\13\
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    \12\ Children in booster seats are part of the target population 
for this proposed rulemaking because they should be restrained with 
the seat belt and so would benefit from a seat belt reminder. The 
transition to a booster seat typically occurs from ages 4-7 years.
    \13\ The Abbreviated Injury Scale (AIS) is a classification 
system for assessing impact injury severity developed and published 
by the Association for the Advancement of Automotive Medicine and is 
used for coding single injuries, assessing multiple injuries, or for 
assessing cumulative effects of more than one injury. MAIS 
represents the maximum injury severity of an occupant at an AIS 
level, i.e., the highest single AIS for a person with one or more 
injuries. MAIS 1 & 2 injuries are considered minor injuries and MAIS 
3-5 are considered serious injuries.
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    Another way to measure benefits is by calculating equivalent lives 
saved (ELS). Equivalent lives saved are the number of prevented 
fatalities added to the number of prevented injuries, with the 
prevented injuries expressed in terms of fatalities (that is, with an 
injury expressed as a fraction of a fatality, so that the more serious 
the injury, the higher the fraction). The estimated equivalent lives 
saved assuming either a 3% or 7% discount rate are presented in table 
2.

[[Page 61678]]

 Table 1--Estimated Annual Benefits--Potential Lives Saved and Injuries
  Prevented for Positive-Only SBWS (Rear Seats), With Estimated 3% & 5%
                          Increase in Belt Use
------------------------------------------------------------------------
              Injury level                   3% (Low)        5% (High)
------------------------------------------------------------------------
MAIS 1..................................            23.2            34.3
MAIS 2..................................            40.2            60.3
MAIS 3..................................             5.6             8.4
MAIS 4..................................             5.5             8.2
MAIS 5..................................             0.2             0.3
                                         -------------------------------
    Total Injuries......................            74.7           111.5
------------------------------------------------------------------------
Fatal...................................            22.3            33.6
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  Table 2--Estimated Annual Benefits--Equivalent Lives Saved--Positive-
                         Only SBWS (Rear Seats)
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                                            3% Discount     7% Discount
            Belt use increase                  rate            rate
------------------------------------------------------------------------
3% increase (Low).......................            21.9            17.7
5% increase (High)......................            32.9            26.7
------------------------------------------------------------------------

    NHTSA also estimates the costs of the proposed requirements for 
rear seat belt warnings. NHTSA estimates that the minimum cost to 
comply with the rear seat belt warning requirements (the positive-only 
system) is $166.44 million (M). This is based on a per-vehicle cost of 
$19.59 for 53.1% of 16M affected new vehicles.
    Based on the forgoing, NHTSA performed benefit-cost and cost-
effectiveness analyses. A benefit-cost analysis calculates the net 
benefits, which is the difference between the benefits flowing from 
injury and fatality reductions and the cost of the rule. The net 
benefit estimates are presented in table 3. The cost-effectiveness 
analysis derives the cost per equivalent life saved, which is equal to 
the total cost of the rule divided by the total fatal equivalents that 
it prevents. These estimates are presented in table 4.

                             Table 3--Net Benefits--Proposed Positive-Only Rear SBWS
                                           [2020 Dollars, in millions]
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                                                                                   Net benefits    Net benefits
    Seat position & belt use        Benefits 3%     Benefits 7%        Cost         3% discount     7% discount
            increase                 discount        discount                          rate            rate
----------------------------------------------------------------------------------------------------------------
3% increase (Low)...............          $262.1          $212.7          $166.4           $95.6           $46.2
5% increase (High)..............           394.8           320.4           166.4           228.3           153.9
----------------------------------------------------------------------------------------------------------------

   Table 4--Cost-Effectiveness Analysis (Cost per Equivalent Life Saved)--Proposed Positive-Only System (Rear
                                                     Seats)
                                           [2020 Dollars, in millions]
----------------------------------------------------------------------------------------------------------------
    Seat position & belt use          ELS 3%          ELS 7%                        Cost/ELS 3%     Cost/ELS 7%
            increase                 discount        discount          Cost          discount        discount
----------------------------------------------------------------------------------------------------------------
3% increase (Low)...............            21.9            17.7          $166.4            $7.6            $9.4
5% increase (High)..............            32.9            26.7           166.4             5.0             6.2
----------------------------------------------------------------------------------------------------------------

    NHTSA is also proposing enhancing the driver seat belt warning 
requirements by requiring an audio-visual warning that remains active 
until the driver's seat belt is buckled and extending the driver's seat 
belt warning requirements, as modified by this NPRM, to the front 
outboard passenger seat. NHTSA estimated the annual benefits of a seat 
belt warning for the driver and outboard front passenger that remains 
active until the occupant's seat belt is buckled as shown in table 5 
and table 6.

Table 5--Estimated Annual Benefits--Lives Saved and Injuries Prevented--Indefinite Duration SBWS (Front Outboard
                                                     Seats)
----------------------------------------------------------------------------------------------------------------
                                                                                       Front
                          Injury level                                Driver         passenger         Total
----------------------------------------------------------------------------------------------------------------
MAIS 1..........................................................            20.7             3.7            24.4
MAIS 2..........................................................           120.0            20.5           140.5
MAIS 3..........................................................            21.6             3.9            25.5

[[Page 61679]]

 
MAIS 4..........................................................            17.4             3.1            20.5
MAIS 5..........................................................             0.5             0.1             0.6
                                                                 -----------------------------------------------
    Total Injuries..............................................           180.2            31.2           211.4
----------------------------------------------------------------------------------------------------------------
Fatal...........................................................            65.9            11.4            77.3
----------------------------------------------------------------------------------------------------------------

       Table 6--Estimated Annual Benefits--Equivalent Lives Saved--Indefinite SBWS (Front Outboard Seats)
----------------------------------------------------------------------------------------------------------------
                                                                                    3% Discount     7% Discount
                                                                   Undiscounted        rate            rate
----------------------------------------------------------------------------------------------------------------
Driver..........................................................            78.7            65.2            52.8
Front Passenger.................................................            13.6            11.3             9.2
                                                                 -----------------------------------------------
    Total.......................................................            92.3            76.5            62.0
----------------------------------------------------------------------------------------------------------------

    NHTSA estimates that the incremental cost of the enhanced seat belt 
warning would be no greater than the currently available seat belt 
warning. Although a seat belt warning is currently not required for the 
front outboard passenger seats, we estimate that 96 percent of new 
vehicles are equipped with them.\14\ NHTSA estimates that the cost for 
equipping a front outboard passenger seat with a seat belt warning 
system is about $2.13 per vehicle. To equip a seat belt warning system 
in the front outboard passenger seat positions on the remaining 4 
percent of new vehicle fleet (16 million) without such a warning is 
$1.36 million (= $2.13 x 0.04 x 16 million).
---------------------------------------------------------------------------

    \14\ Based on data on total projected vehicle sales in the 
United States for model year 2022 from the agency's New Car 
Assessment Program Purchasing with Safety in Mind: What to Look For 
When Buying a Vehicle program.
---------------------------------------------------------------------------

    The total monetized benefits, costs, and net benefits (total 
monetized benefits--total cost) of the enhanced seat belt warning 
system for the driver and front passenger is shown in table 7.

                           Table 7--Annual Monetized Benefits, Costs and Net Benefits--Indefinite SBWS (Front Outboard Seats)
                                                               [2020 Dollars, in millions]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Driver                            Front Passenger                 Driver and Front Passenger
                                       -----------------------------------------------------------------------------------------------------------------
                                        Undiscounted      3%          7%      Undiscounted      3%          7%      Undiscounted      3%          7%
--------------------------------------------------------------------------------------------------------------------------------------------------------
Passenger car Benefits................        $422.5      $353.0      $288.0         $79.9       $66.7       $54.4        $502.4      $419.7      $342.4
Light Truck & Van Benefits............         520.4       427.6       344.8          83.4        68.5        55.2         603.8       496.1         400
                                       -----------------------------------------------------------------------------------------------------------------
    Total Benefits....................         942.9       780.5       632.8         163.3       135.2       109.7       1,106.2       915.8       742.5
    Total Costs.......................             0           0           0          1.36        1.36        1.36          1.36        1.36        1.36
--------------------------------------------------------------------------------------------------------------------------------------------------------
Net Benefits..........................         942.9       780.5       632.8         161.9       133.9       108.3       1,104.8       914.4       741.1
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The net benefits of the proposed rule requiring seat belt warning 
for rear seating positions and the enhanced seat belt warning for the 
front outboard seats are shown in table 8.

Table 8--Net Benefits From the Proposal (SBWS for Rear Seating Positions
        and Indefinite SBWS for Front Outboard Seating Positions)
                       [2020 Dollars, in millions]
------------------------------------------------------------------------
                                            3% Discount     7% Discount
                                               rate            rate
------------------------------------------------------------------------
Front Outboard Seats....................          $914.4          $741.1
Rear Seats (3% increase in rear seat                95.6            46.2
 belt use)..............................
Rear Seats (5% increase in rear seat               228.3           153.9
 belt use)..............................
                                         -------------------------------
    Total Net Benefits (3% increase in           1,010.0           787.4
     rear belt use).....................
    Total Net Benefits (5% increase in           1,142.7           895.0
     rear belt use).....................
------------------------------------------------------------------------

[[Page 61680]]

II. Background

    In 2020, there were 39,007 motor vehicle traffic fatalities in the 
United States.\15\ This was 2,652 more fatalities than in 2019.\16\ In 
2021, motor vehicle traffic fatalities increased again to 42,939.\17\ 
The traffic fatality count in 2021 is the highest since 2005 (43,510) 
and represents the second year-to-year increase since 2019.\18\ The 10-
percent fatality increase from 2020 to 2021 is the highest year-to-year 
percentage increase since FARS started data collection in 1975.\19\ 
NHTSA has preliminary estimated 42,795 fatalities in 2022, representing 
a small decrease of about 0.3% from 2021.\20\ The Department of 
Transportation has released a comprehensive National Roadway Safety 
Strategy to address this rise in roadway fatalities and injuries.\21\ 
Part of that strategy is making vehicles safer.
---------------------------------------------------------------------------

    \15\ Stewart, T. (April 2023). Overview of Motor Vehicle Traffic 
Crashes in 2021(Report NO. DOT HS 813 435. National Highway Traffic 
Safety Administration, pg. 5.
    \16\ Id. at pg. 2.
    \17\ Id. at pg. 5.
    \18\ Id.
    \19\ Id. The 2021 and 2022 fatality estimates are not entirely 
final, and may change somewhat as NHTSA receives further updates or 
corrections.
    \20\ See https://www.transportation.gov/briefing-room/nhtsa-estimates-2022-show-roadway-fatalities-remain-flat-after-two-years-dramatic. Though NHTSA acknowledges fatalities essentially remained 
flat in 2022, NHTSA does not know if this trend will continue to 
remain flat or if there will be further increases in fatalities.
    \21\ https://www.transportation.gov/sites/dot.gov/files/2022-02/USDOT-National-Roadway-Safety-Strategy.pdf.
---------------------------------------------------------------------------

    This NPRM proposes to require a seat belt use warning system for 
the rear seats of passenger cars, trucks, buses (except school buses), 
and multipurpose passenger vehicles (MPVs) with a GVWR of 4,536 kg 
(10,000 lb) or less. This NPRM also proposes to enhance the existing 
front seat belt warning requirements, including requiring a seat belt 
warning for the front outboard passenger seat and increasing the 
duration of the warning. This section provides a brief introduction to 
seat belt technology, evidence on seat belt use by vehicle occupants, 
and strategies to increase belt use.
    Using a seat belt is one of the most effective actions a motor 
vehicle occupant can take to prevent death and injury in a crash.\22\ 
Seat belts protect occupants in various ways. They prevent occupants 
from being ejected from the vehicle, gradually decelerate the occupant 
as the vehicle deforms and absorbs energy, and reduce the occurrence of 
occupant contact with harmful interior surfaces and other 
occupants.\23\ Seat belts are effective in most types of crashes 
(although effectiveness varies for different types of crashes). 
Research has found that seat belts greatly reduce the risk of fatal and 
non-fatal injuries compared to the risk faced by unrestrained 
occupants. For rear seat occupants, seat belts reduce the risk of 
fatality by 55% (for passenger cars) and 74% (for light trucks and 
vans). For front seat occupants, drivers and right front passengers, 
seat belts reduce the risk of fatality by 44% (for passenger cars) and 
63% to 73% (for light trucks and vans). Seat belts reduce the risk of 
injuries by up to 63%.\24\ While the PRIA makes use of these 
effectiveness rates, we note that the effectiveness of seat belts is 
not impacted by the proposed rule. Instead, benefits from the proposed 
rule are the result of the increase in seat belt use resulting from the 
warning.
---------------------------------------------------------------------------

    \22\ See, e.g., 68 FR 46262 (Aug. 5, 2003). See also Buckling 
Up: Technologies to Increase Seat Belt Use. Special Report 278 at 
18, Committee for the Safety Belt Technology Study, Transportation 
Research Board of The National Academies (2003) [hereinafter 
``Transportation Research Board Study''].
    \23\ Charles J. Kahane, Lives Saved by Vehicle Safety 
Technologies and Associated Federal Motor Vehicle Safety Standards, 
1960 to 2012--Passenger Cars and LTVs--With Reviews of 26 FMVSS and 
the Effectiveness of Their Associated Safety Technologies in 
Reducing Fatalities, Injuries, and Crashes. 89 DOT HS 812 069 at 89, 
Department of Transportation, National Highway Traffic Safety Agency 
(2015) [hereinafter ``DOT Lives Saved Study''].
    \24\ See the Preliminary Regulatory Impact Analysis (PRIA) (in 
the docket for this rulemaking) for these effectiveness estimates.
---------------------------------------------------------------------------

    While seat belt use is meaningfully higher than it was a decade 
ago, there is room for improvement. Usage rates for rear belts have 
consistently been below those for the front seats, and while front seat 
belt use rates increased early in the previous decade, for the last 
several years they have plateaued. According to data from NHTSA's 
National Occupant Protection Use Survey (NOPUS), from 2012 to 2021, 
seat belt use was lower in the rear seat than in the front seat, 
ranging from a difference of 8.8 percent in 2013 (78.3% vs. 87.1%) to 
14.3 percent in 2017 (75.4% vs. 89.7%).\25\ During that time, front 
seat belt use rates ranged from 86.1% in 2012 to 90.7% in 2019. In 
2021, front seat belt use was 90.4% and rear seat belt use was 77.9 
percent.\26\ See Figure 1.
---------------------------------------------------------------------------

    \25\ Boyle, L.L. (2022, August). Occupant restraint use in 2021: 
Results from the NOPUS Controlled Intersection Study (Report No. DOT 
HS 813 344). National Highway Traffic Safety Administration. NOPUS 
is the only nationwide probability-based observational survey of 
seat belt use in the United States. The survey observes seat belt 
use as it actually occurs at randomly-selected roadway sites, and 
involves a large number of occupants (68,804 in 2021). NOPUS 
observations are made during daylight hours and are not necessarily 
representative of high-risk driving times when belt use may be 
lower.
    \26\ Id.
    [GRAPHIC] [TIFF OMITTED] TP07SE23.000
    

[[Page 61681]]

    Consumer survey research by NHTSA and others (such as the Insurance 
Institute for Highway Safety and academic researchers) suggests that 
many unbelted occupants are likely amenable to using a seat belt. Seat 
belt nonusers can be categorized as either ``part-time'' nonusers or 
so-called ``hard-core'' nonusers.\27\ Part-time nonusers generally 
express positive attitudes toward seat belts, but do not always buckle 
up, due to a range of reasons, such as short trips, forgetfulness, and 
being in a rush.\28\ Hard-core nonusers are those who ``generally do 
not acknowledge the benefits of seat belts and are opposed to their 
use.'' \29\ Research by NHTSA and others suggests that most nonusers 
are part-time nonusers, not hard-core nonusers. This is true even for 
front seat occupants, for which there is a relatively high rate of 
observed seat belt use. For instance, NHTSA's most recent survey of 
seat belt use found that approximately 83% of drivers who did not 
always use a seat belt reported using a seat belt most or some of the 
time, and only 17% were hard-core nonusers who used seat belts rarely 
or never.\30\ Similarly, for those who did not always use a seat belt 
when riding as a passenger in the front, 89% used seat belts most or 
some of the time while only 11% used a seat belt rarely or never.\31\ 
The same was true for rear seat passengers who did not always use a 
belt, of whom 70% used a belt most or some of the time, while only 30% 
used a belt rarely or never.\32\ Moreover, of the survey respondents 
who reported ``always'' using a seat belt while driving, only 66% 
``always'' used a seat belt when riding as a passenger in the rear 
seat.\33\
---------------------------------------------------------------------------

    \27\ See, e.g., Transportation Research Board Study at 3.
    \28\ See, e.g., Transportation Research Board Study at 32; 
Spado, D., Schaad, A., & Block, A. (2019, December). 2016 motor 
vehicle occupant safety survey; Volume 2: Seat belt report (Report 
No. DOT HS 812 727). National Highway Traffic Safety Administration, 
at p. 71 (Fig. 53); p. 76 (Fig. 54). This is a national telephone 
survey periodically conducted by NHTSA. Because, unlike NOPUS, it is 
not observational, the MVOSS is not the best indicator of national 
belt use. In addition, because of respondent bias, the large number 
of part-time users, and the tendency for survey respondents to over-
report belt use, MVOSS use rates have typically been about 10 
percentage points higher than those from NOPUS, which is an 
observational study, and therefore a more objective and accurate 
measure of belt use. MVOSS does, however, provide demographic detail 
that cannot be observed and insight into the reasons people do and 
do not use seat belts.
    \29\ Transportation Research Board Study at 40.
    \30\ 2016 MVOSS, p.7 (calculated from Fig. 5).
    \31\ Id. at p. 12 (calculated from Fig. 10).
    \32\ Id. at p. 13 (calculated from Fig. 11).
    \33\ Id. at p. 64 (Table 15). The MVOSS results are consistent 
with, though differ somewhat from, those in a similar survey 
conducted by the Agency for Healthcare Research and Quality. Chu, M. 
Characteristics of Persons Who Seldom or Never Wear Seat Belts, 
2002. Statistical Brief #62. December 2004. Agency for Healthcare 
Research and Quality, Rockville, MD. http://meps.ahrq.gov/mepsweb/data_files/publications/st62/stat62.pdf. The reader is referred to 
the discussion in Section XIV.A.2 and in the PRIA, section 4.3.
---------------------------------------------------------------------------

    NHTSA has, over time, tried a variety of such strategies, including 
sponsoring national media campaigns, supporting the enactment of state 
seat belt use laws and high-visibility enforcement, and facilitating or 
requiring vehicle-based strategies.\34\ Some of these strategies are 
non-regulatory; some are regulatory. One example of a non-regulatory 
strategy is NHTSA's annual Click It or Ticket mobilization, which 
includes a national advertising campaign backed up by high-visibility 
local enforcement of state seat belt laws. Adult rear-seat passengers 
are covered by seat belt laws in 32 states and the District of 
Columbia. Some of these states with mandatory rear seat belt laws 
include rear-seat specific messaging in their media campaigns. While 
such measures have helped make enormous progress, the persistent gaps 
in seat belt use suggest that additional approaches may be necessary.
---------------------------------------------------------------------------

    \34\ NHTSA runs a Congressionally mandated High Visibility 
Enforcement (HVE) annual campaign focused on increasing seat belt 
use. The Click It or Ticket (CIOT) nationwide campaign has been in 
effect for about 20 years. It runs every year from Mid-May through 
the Memorial Day weekend, into the first week in June.
---------------------------------------------------------------------------

    Seat belt warning systems are a vehicle-based strategy to increase 
belt use. Seat belt warning systems encourage seat belt use by 
reminding unbuckled occupants to fasten their belts and/or by informing 
the driver that a passenger is unbelted, so that the driver can request 
the unbelted occupant to buckle up.\35\ The warnings provided by seat 
belt warning systems typically consist of visual and/or audible 
signals. An optimized warning system balances effectiveness and 
annoyance, so that the warning is noticeable enough that the occupants 
will be motivated to fasten their belts, but not so intrusive that an 
occupant may attempt to circumvent or disable it or the public will not 
accept it.\36\ Research by NHTSA and others shows that seat belt 
warning systems are effective at getting unbuckled occupants to fasten 
their seat belt. (We take a closer look at this research in Section V 
and Section XIV.A, as well as the PRIA.)
---------------------------------------------------------------------------

    \35\ Akamatsu, M., Hashimoto, H., and Shimaoka, S., ``Assessment 
Method of Effectiveness of Passenger Seat Belt Reminder,'' SAE 
Technical Paper 2012-01-0050, 2012, doi:10.4271/2012-01-0050.
    \36\ See, e.g., Transportation Research Board Study at 8, 25; 
Mark Freedman et al., Effectiveness and Acceptance of Enhanced Seat 
Belt Reminder Systems: Characteristics of Optimal Reminder Systems 
Final Report. DOT HS 811 097 at 2 (Feb. 2009) (hereinafter ``DOT 
2009 Seat Belt Study'').
---------------------------------------------------------------------------

    Federal Motor Vehicle Safety Standard (FMVSS) No. 208, ``Occupant 
crash protection,'' requires a short-duration audio-visual seat belt 
warning for the driver's seat belt on passenger cars and most light- 
and medium-duty trucks, MPVs, and buses. (Later in this section we 
discuss the current requirements in more detail.) The visual component 
of the warning generally must be at least sixty seconds long, and the 
audible component must be at least four seconds long. The regulations 
do not require seat belt warnings for any seating position other than 
the driver's seat.
    Although not required by NHTSA's regulations, most currently 
produced vehicles have a seat belt warning for the front outboard 
passenger seat. Almost all (96.6%) MY 2022 vehicles offered for sale in 
the United States are equipped with a seat belt warning for the front 
outboard passenger seat. Further, almost all vehicles already provide 
an audio-visual seat belt warning for both front outboard seats that is 
longer than the minimum warning for the driver's seat belt currently 
required in FMVSS No. 208. However, the persistence of the front seat 
belt warning, while greater than the very minimal durations required by 
FMVSS No. 208, is not consistent across currently produced vehicles. 
Specifically, a little over half of MY 2022 vehicles provide a visual 
warning that lasts until the belts at any occupied front outboard seat 
are fastened, and while almost all (about 93%) have an audible warning 
lasting at least a minute and a half, less than half have an audible 
warning that lasts at least two minutes.\37\ This means that while many 
currently produced vehicles have significantly enhanced reminders, many 
do not. This, along with the plateauing front seat belt use numbers 
suggests that the current regulatory minima are too short, and that in 
the absence of a requirement, persistent audible reminders that could 
improve front seat belt use may not be widely provided in the market.
---------------------------------------------------------------------------

    \37\ See Section XI.C.1, Increasing the duration of the audio-
visual warning on vehicle start-up.
---------------------------------------------------------------------------

    On the other hand, while almost all model year MY 2022 vehicles 
have a seat belt warning for the front outboard passenger seat, under 
half come equipped with a rear seat belt warning system. Rear seat belt 
warnings were first introduced in the United States by Volvo around 
2009. Based on data on total projected vehicle sales in the United 
States for model year (MY) 2022

[[Page 61682]]

from the agency's New Car Assessment Program (NCAP) Purchasing with 
Safety in Mind: What to Look For When Buying a Vehicle program, about 
46.9 percent are equipped with a rear seat belt warning system.\38\ 
Based on this MY 2022 data, fifteen vehicle manufacturers offer 
vehicles for sale in the United States with rear seat belt warning 
systems. Thus, while rear seat belt warnings have become more widely 
deployed in recent years, the majority of the current fleet still is 
not equipped with them.
---------------------------------------------------------------------------

    \38\ Through the NCAP program, NHTSA sends annual requests for 
safety information about new vehicles to vehicle manufacturers. This 
includes specific questions on seat belt reminder systems. The focus 
of this request for information is for vehicle models that will be 
sold in the upcoming model year that have a GVWR of 4,536 kg (10,000 
lbs.) or less, and this data generally covers all such vehicles 
offered for sale in the U.S. for MY 2022. Throughout this document 
we will refer to this data as our ``NCAP data'' or ``Purchasing with 
Safety in Mind: What to Look For When Buying a Vehicle'' data or 
information.
---------------------------------------------------------------------------

    The benefits of increasing seat belt use could be sizable. The 
National Academy of Sciences has noted that ``even a small increase in 
belt use should have large benefits.'' \39\ The size of the unbelted 
fatality problem for front seats means that even a very modest 
improvement in seat belt use will have a meaningful benefit. Our 
analysis found that even a 1% increase in belt usage for the driver's 
seat resulted in a significant number of lives saved. With respect to 
the rear seats, ``while the overall proportion of person-trips taken as 
a rear-seat occupant in the U.S. is relatively low (12.9%), at-risk 
travel exposure by rear-seat passengers at a national level is 
substantial (approximately 39 billion annual person-trips).'' \40\ 
Moreover, children are proportionally much more likely to be rear seat 
passengers than adults,\41\ and the increased prevalence of ridesharing 
services has likely increased the prevalence of rear-seat passengers.
---------------------------------------------------------------------------

    \39\ Transportation Research Board Study at 19 (citing Donna 
Glassbrenner. 2002. Safety Belt and Helmet Use in 2002--Overall 
Results. DOT HS 809 500. Washington, DC: U.S. Department of 
Transportation, National Highway Traffic Safety Administration).
    \40\ Matthew J. Trowbridge & Richard Kent, Rear-Seat Motor 
Vehicle Travel in the U.S.: Using National Data to Define a 
Population at Risk. Am. J. Prev. Med. 37(4), 321-3 (2009).
    \41\ Trowbridge & Kent at 322.
---------------------------------------------------------------------------

    In short, front seat belt use rates appear to have plateaued, and 
rear seat belt use rates have persistently been below those for the 
front seats. Moreover, unbuckled occupants continue to be 
overrepresented in fatal crashes (51%), given the lower exposure of 
unbelted occupants relative to belted occupants (because front seat 
belt use was about 90% and rear seat belt use was 80%). Nevertheless, 
in spite of the effectiveness of seat belts and seat belt warnings, 
most new vehicles continue to lack a rear seat belt warning, and, while 
many provide significantly enhanced reminders for the front seats, many 
do not. This suggests a need for a beneficial safety technology that is 
not being met in the vehicle market. This NPRM is intended to meet that 
need.
    In Section VI and Section XIV below, and in the PRIA, we take a 
detailed look at the estimated target population, effectiveness of 
front and rear belt warnings, and benefits and costs of this proposal.

III. Regulatory and Legislative History

Current Driver's Seat Belt Warning Requirements

    FMVSS No. 208 is intended to reduce the likelihood of occupant 
deaths and the likelihood and severity of occupant injuries in crashes. 
The standard took effect in 1968 and from its inception required seat 
belts in passenger cars.\42\
---------------------------------------------------------------------------

    \42\ 32 FR 2408, 2415 (Feb. 3, 1967).
---------------------------------------------------------------------------

    The standard currently requires a seat belt warning for the 
driver's seat belt on passenger cars; \43\ trucks and MPVs with a GVWR 
of 4,536 kg (10,000 lb) or less (except for some compliance options 
which do not require the warning); \44\ and buses with a GVWR of 3,855 
kg (8,500 lb) or less and an unloaded weight less than or equal to 
2,495 kg (5,500 lb).\45\ The regulations do not require seat belt 
warnings for any seating position other than the driver's seat.\46\
---------------------------------------------------------------------------

    \43\ S4.1.5.1(a)(3); S7.3.
    \44\ S4.2.6; S7.3.
    \45\ S4.2.6 (with the exception of some compliance options).
    \46\ See, e.g., Interpretation Letter from NHTSA to R. Lucki, 
July 24, 1985 (``Thus, the intent was to require a warning system 
for only the driver's position.''). All NHTSA interpretation letters 
cited in this preamble are available at http://isearch.nhtsa.gov/search.htm.
---------------------------------------------------------------------------

    Manufacturers have two compliance options for the driver's 
warning.\47\ The first option requires that if the key is in the ``on'' 
or ``start'' position and the seat belt is not in use, the vehicle must 
provide a visual warning for at least 60 seconds, and an audible 
warning that lasts 4 to 8 seconds. Under the second option, when the 
key is turned to the ``on'' or ``start'' position, the vehicle must 
provide a visual warning for 4 to 8 seconds (regardless of whether the 
driver seat belt is fastened) and an audible warning lasting 4 to 8 
seconds if the driver seat belt is not in use.\48\
---------------------------------------------------------------------------

    \47\ 49 CFR 571.208, S7.3.
    \48\ The warning requirements for automatic belts in S4.5.3 
mirror, with some differences, the first compliance option. 
Automatic belts are rarely, if ever, installed in current production 
vehicles, and NHTSA's regulations limit the seating positions for 
which automatic belts may be used to rear seats.
---------------------------------------------------------------------------

Early NHTSA Experiences With Seat Belt Warnings

    Between 1967 and 1974, NHTSA promulgated a series of different 
occupant protection regulations that specified as compliance options 
various combinations of active and passive occupant crash protection, 
seat belt interlocks, and seat belt warnings.\49\ A seat belt warning 
was first required in 1971, when NHTSA sought to increase seat belt use 
by adopting occupant protection compliance options that included the 
use of a seat belt warning for the front outboard seating 
positions.\50\ This seat belt warning option required audible and 
visible warning signals that lasted for as long as the occupant was 
unbelted, the ignition was ``on,'' and the transmission was in forward 
or reverse. In 1972, NHTSA adopted occupant protection options for 
passenger cars that included (for cars that did not provide automatic 
protection) an interlock system that would prevent the engine from 
starting if any of the front seat belts were not fastened.\51\ Contrary 
to the agency's expectations, the initial vehicle introduction of these 
systems in the early 1970s was not well-received by the public. In 
particular, continuous buzzers and ignition interlocks annoyed many 
consumers to the point of their disabling or circumventing the systems.
---------------------------------------------------------------------------

    \49\ ``Active protection'' refers to features, such as manual 
seat belts, that require action by the occupant, while ``automatic 
protection'' or ``passive protection'' refers to safety features 
that do not require any action by the occupant other than sitting in 
a designated seating position. Seat belt interlocks prevent starting 
or operating a motor vehicle if an occupant is not using a seat 
belt. For a fuller discussion of the history of the active and 
passive protection requirements in FMVSS No. 208, see Stephen R. 
Kratzke, Regulatory History of Automatic Crash Protection in FMVSS 
208. SAE Technical Paper 950865, International Congress and 
Exposition, Society of Automotive Engineers, Detroit, Michigan, Feb. 
27-March 2 (1995).
    \50\ 36 FR 4600 (May 10, 1971).
    \51\ 37 FR 3911 (Feb. 24, 1972).
---------------------------------------------------------------------------

    As a result of the negative consumer reaction, Congress adopted a 
provision, as part of the Motor Vehicle and School Bus Safety 
Amendments of 1974, prohibiting NHTSA from prescribing a motor vehicle 
safety standard that required, or permitted as a compliance option, 
seat belt interlocks or audible seat belt warnings lasting longer than 
eight seconds.\52\ In response, NHTSA amended FMVSS No. 208 in 1974 to 
require that only the driver seating

[[Page 61683]]

position be equipped with a seat belt warning system providing a visual 
and audible warning, with the audible warning not lasting longer than 
eight seconds.\53\ The limited-duration driver's seat belt warning 
requirement has remained in the standard, with some changes, since 
1974. Since that time FMVSS No. 208 has not been amended to require 
seat belt warnings for any passenger seating positions.
---------------------------------------------------------------------------

    \52\ These amendments were codified at 49 U.S.C. 30124. As 
explained below, the provisions were amended in 2012 by the Moving 
Ahead for Progress in the 21st Century Act.
    \53\ 39 FR 42692 (Dec. 6, 1974).
---------------------------------------------------------------------------

Recent Regulatory History

    In 2001, the House Committee on Appropriations directed NHTSA to 
contract with the Transportation Research Board (TRB) of the National 
Academy of Sciences to conduct a study on the benefits and 
acceptability of minimally intrusive vehicle technologies to increase 
seat belt use.\54\ The Committee also requested that the study consider 
potential legislative and regulatory actions to facilitate installation 
of devices to encourage seat belt use. The TRB report (published in 
2004) found that new seat belt use technologies existed that could 
increase belt use without being overly intrusive.\55\ It recommended 
that rear seat belt warning systems be developed and that NHTSA 
undertake a broad, multi-year program of research on the effectiveness 
and acceptability of different seat belt warning systems to establish a 
basis for future regulation. It also recommended that Congress amend 
the Safety Act to eliminate the 8-second limit on the length of the 
audible warning.
---------------------------------------------------------------------------

    \54\ House Report 107-108, June 22, 2001.
    \55\ Transportation Research Board Study at 9.
---------------------------------------------------------------------------

    In 2002 and 2003, NHTSA sent letters to several vehicle 
manufacturers encouraging them to enhance seat belt warning systems 
beyond the FMVSS No. 208 minimum requirements.\56\ The agency 
facilitated the voluntary adoption of enhanced warnings through a 
series of legal interpretations that determined that the Safety Act did 
not prohibit manufacturers from implementing enhanced warning systems 
as long as the manufacturer provided some means of differentiating the 
voluntarily-provided signal from the required signal (for example, by a 
clearly distinguished lapse in time between the two signals).\57\ (An 
``enhanced'' system is one with visual and/or audible warning signals 
that exceed the durations specified in FMVSS No. 208, S7.3, and/or that 
applies to seating positions other than the driver's seat. A ``basic'' 
system is one that simply meets the minimum requirements in FMVSS No. 
208.) Many vehicle manufacturers subsequently implemented enhanced seat 
belt warnings for the driver and right front outboard seating 
positions. Based on information submitted to the agency in connection 
with NCAP, for MY 2022, 99.6 percent of participating vehicle models 
offered for sale in the United States had an enhanced warning (audible 
and/or visual) for the driver, right front passenger, or both.
---------------------------------------------------------------------------

    \56\ See Docket No. NHTSA-2002-13226.
    \57\ See Docket Nos. NHTSA-2001-9899, NHTSA-2002-13379, NHTSA-
2003-14742, NHTSA-2003-15006, and NHTSA-2003-15156.
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    In 2005, Congress passed legislation--the Safe, Accountable, 
Flexible, and Efficient Transportation Equity Act--a Legacy for Users 
(SAFETEA-LU) \58\--that required NHTSA to evaluate the effectiveness 
and acceptability of several different types of enhanced seat belt 
warnings offered by a number of manufacturers. In response, the agency 
conducted a comprehensive multi-phase research study (explained in 
Section V below).
---------------------------------------------------------------------------

    \58\ Public Law 109-59, 10306 (2005).
---------------------------------------------------------------------------

    On November 21, 2007, Public Citizen and Advocates for Highway and 
Auto Safety (Advocates, and, collectively, petitioners) petitioned 
NHTSA to amend FMVSS No. 208 to require a seat belt warning system for 
rear seats on passenger cars and MPVs with a GVWR of 4,536 kg (10,000 
lb) or less.\59\ The petitioners noted that primary enforcement laws 
typically do not cover rear seat occupants and that studies have 
indicated that warnings for rear seat belts would significantly 
increase rear passenger seat belt use. The petitioners stated that rear 
seat belt warnings are technologically feasible and would be less 
costly if they were required in all vehicles. The petitioners provided 
a range of estimates of how much a rear seat belt warning system could 
increase rear belt use. The petitioners stated that rear seat belt 
warnings would save hundreds of lives each year and that a large 
percentage of the lives saved would be children. As noted in the 
ANPRM,\60\ NHTSA granted the petition.
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    \59\ Docket No. NHTSA-2010-0061-0002.
    \60\ 84 FR 51076 (Sept. 27, 2019).
---------------------------------------------------------------------------

    On June 29, 2010, the agency published a Request for Comments 
document (RFC) on the petition.\61\ The RFC discussed the agency's 
research and findings regarding requiring rear seat belt warnings and 
solicited comments.
---------------------------------------------------------------------------

    \61\ 75 FR 37343 (June 29, 2010) (Docket No. NHTSA-2010-0061).
---------------------------------------------------------------------------

    The agency received 26 comments. Five commenters opposed requiring 
rear seat belt warnings: Ford Motor Company, General Motors, the 
Alliance of Automobile Manufacturers (Alliance), the Association of 
International Automobile Manufacturers,\62\ and a commenter from the 
general public. These commenters believed that a requirement for rear 
seat belt warnings was premature and that it should remain voluntary, 
and some supported using NCAP to encourage their penetration in the 
market. Among those that supported requiring rear seat belt warnings 
were IEE S.A., Consumers Union, the Insurance Institute for Highway 
Safety (IIHS), the Automotive Occupant Restraint Council (now known as 
the Automotive Safety Council), and the American Academy of Pediatrics.
---------------------------------------------------------------------------

    \62\ The Association of International Automobile Manufacturers 
subsequently became the Association of Global Automakers (Global). 
The Alliance and Global have merged to become the Alliance for 
Automotive Innovation.
---------------------------------------------------------------------------

    In 2012, Congress passed the Moving Ahead for Progress in the 21st 
Century Act (MAP-21).\63\ That legislation contains two provisions 
regarding seat belt warning systems. First, it repeals the 8-second 
durational limit for the driver's seat belt audible warning.\64\ 
Second, it requires the Secretary of DOT to initiate a rulemaking 
proceeding to amend FMVSS No. 208 to provide a safety belt use warning 
system for designated seating positions in the rear seat.\65\ It 
directs the Secretary to either issue a final rule, or, if the 
Secretary determines that such an amendment does not meet the 
requirements and considerations of 49 U.S.C. 30111,\66\ to submit a 
report to Congress describing the reasons for not prescribing such a 
standard.
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    \63\ Public Law 112-141 (2012).
    \64\ Id. at section 31202(a)(2) (repealing portion of 49 U.S.C. 
30124).
    \65\ Id. at section 31503. Authority has been delegated to 
NHTSA. 49 CFR 1.95.
    \66\ Section 30111 requires that a Motor Vehicle Safety Standard 
meet the need for safety, be stated in objective terms, and be 
practicable, among other requirements. See infra Section VIII.
---------------------------------------------------------------------------

    In accordance with MAP-21, in early 2013 NHTSA initiated a 
rulemaking proceeding when it submitted for public comment a proposal 
to undertake a study regarding the effectiveness of existing rear seat 
belt warning systems.\67\ (The results of this study are discussed in 
Section V below.) In 2017, the Center for Auto Safety and Kids and Cars 
filed a petition for a writ of mandamus in the United States Court of 
Appeals for the District of Columbia Circuit to compel DOT to initiate 
and complete a rulemaking to require a rear

[[Page 61684]]

seat belt warning.\68\ The Court subsequently denied the petition 
without prejudice to renewal in the event of significant additional 
agency delay.\69\ In 2019, NHTSA published an Advance Notice of 
Proposed Rulemaking seeking comment on a variety of issues related to 
potential rear seat belt warning requirements. The ANPRM is discussed 
in Section VII.
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    \67\ 78 FR 5865 (Jan. 28, 2013).
    \68\ In re Kids and Cars, Inc., No. 17-1229, Doc. 1702061 (D.C. 
Cir. filed Oct. 30, 2017).
    \69\ In re Kids and Cars, Inc., No. 17-1229 (D.C. Cir. June 5, 
2018).
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IV. ECE Requirements and Euro NCAP

ECE Requirements

    The European Union has issued an updated version of Regulation No. 
16 \70\ of the Economic Commission for Europe of the United Nations 
(UNECE) that requires seat belt reminder systems in all front and rear 
seats on new cars.\71\ The seat belt reminder system is required to 
have both a start-of-trip warning and a change-of-status warning for 
both the rear and front seats, though the exact requirements differ 
somewhat for rear and front seats.
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    \70\ ECE Regulation No. 16, Revision 10.
    \71\ The regulation was introduced in two phases: September 1, 
2019 for new vehicle types (i.e., applied to all vehicle models that 
get a new type approval) and September 1, 2021 for all newly 
produced and registered vehicles.
---------------------------------------------------------------------------

    Rear seat requirements. R16 specifies a two-level warning. The 
first-level warning is a visual warning and the second-level warning is 
an audio-visual warning. The first-level warning applies at the start 
of a trip and the second-level warning applies when a fastened belt 
becomes unfastened during a trip. The first-level warning must activate 
when the seat belt of any of the rear seats is not fastened and the 
ignition switch or master control switch is activated. The first-level 
warning must last at least 60 seconds or until the belt is fastened (or 
the seat is no longer occupied, if equipped with occupant detection). 
The second-level warning must activate when a belt becomes unfastened 
and certain specified speed or distance thresholds are met and must 
last for 30 seconds unless other specified criteria are met (e.g., the 
belt is re-fastened).
    Front seat requirements. The front seat belt warning requirements 
are similar to the rear seat warnings, with some differences. First, 
the first-level visual warning is only required to last 30 seconds, not 
60 seconds. Second, the second-level warning applies to unfastened 
belts at the start of the trip as well as to changes in belt status.
    The regulation also contains a variety of other requirements 
relating to the seat belt warning systems (e.g., telltales, exemptions 
for certain vehicles and seating positions). R16 also allows for short 
and long-term deactivation of both front and rear warnings.
    The ECE requirements are discussed in more detail where relevant in 
later sections of this preamble.

Euro NCAP

    Euro NCAP introduced bonus points for seat belt warnings in 2002. 
The Euro NCAP protocol for Safety Assist systems describes which 
features a seat belt reminder must have to qualify for extra 
points.\72\
---------------------------------------------------------------------------

    \72\ European New Car Assessment Programme Assessment Protocol--
Safety Assist, Version 9.1, November 2021.
---------------------------------------------------------------------------

    Rear seat warnings. For rear seats, a visual signal must start once 
the ignition switch is engaged. The visual signal must be at least 60 
seconds long. Occupant detection is not required for rear seats, but 
systems that feature rear seat occupant detection are eligible for 
higher scores. For systems without occupant detection, the visual 
signal must clearly indicate to the driver which seat belts are in use 
and not in use. For systems with occupant detection on all rear seating 
positions, the visual signal does not need to indicate the number of 
seat belts in use or not in use, but the signal must remain active if a 
seat belt remains unfastened on any of the occupied seats in the rear. 
No visual signal is required if all the rear occupants are belted. For 
systems with rear seat occupant detection, a 30-second audible signal 
needs to activate before the vehicle reaches a speed of 25 km/h or 
before it travels 500 meters when any occupied seat has an unbuckled 
belt.\73\ When any seat belt experiences a change of status at vehicle 
speeds above 25 km/h, an audio-visual signal is required, with the 
visual signal lasting 60 seconds and the audible warning lasting 30 
seconds, unless certain conditions are met.
---------------------------------------------------------------------------

    \73\ For front seat belts, the assessment protocol requires both 
a visual and an audible warning signal. The front occupant visual 
signal must remain active until the seat belt is fastened. The 
audible signal for the front occupants has two stages, an initial 
and final audible signal, which have different onset criteria. The 
initial audible signal must not exceed 30 seconds and the final 
audible signal must be at least 90 seconds. To prevent unnecessary 
signals, the system must also be capable of detecting whether the 
front passenger seat is occupied.
---------------------------------------------------------------------------

    Front seat warnings. The Euro NCAP protocol requires that, in order 
to receive points, at the start of a trip the system must provide a 
visual seat belt warning that lasts until the belt is fastened \74\ and 
an audible warning that activates when certain conditions are met and 
generally must last at least about 90 seconds (the exact duration 
depends on a variety of specified criteria, such as vehicle speed or 
distance travelled). It also specifies an audio-visual change-of-status 
warning that meets the requirements of the initial start of trip 
warning.
---------------------------------------------------------------------------

    \74\ Sction 3.4.2.1.
---------------------------------------------------------------------------

V. NHTSA Research on Effectiveness and Acceptance of Seat Belt Warning 
Systems

    NHTSA has taken a variety of actions to research the effectiveness 
and acceptance of seat belt warnings.
    In 2002 the agency chartered an integrated project team to 
recommend strategies for increasing seat belt use.\75\ The team's 
report, issued in 2003, observed that ``[d]espite the significant 
increases over the past twenty years, safety belt use in the United 
States falls short of that in some industrialized nations.'' \76\ The 
report also noted that there are a ``wide range of initiatives . . . 
that have the potential to raise and/or sustain safety belt use 
rates.'' The report went on to identify several such initiatives, which 
it classified as either behavioral or vehicle-based. The behavioral 
strategies included upgrading existing State seat belt laws, high-
visibility enforcement campaigns, a national communications plan, 
employer policies and regulation, and insurance industry collaboration. 
The vehicle-based strategies included encouraging vehicle manufacturers 
to voluntarily install enhanced seat belt warning systems, providing 
consumer information on vehicles equipped with enhanced warning systems 
as part of NCAP, and continued monitoring and assessment of the 
effectiveness and acceptability of enhanced seat belt warnings through 
research.
---------------------------------------------------------------------------

    \75\ See 68 FR 46262 (Aug. 5, 2003).
    \76\ U.S. Department of Transportation, National Highway Traffic 
Safety Administration. July 2003. Initiatives to Address Safety Belt 
Use, available at www.regulations.gov (docket NHTSA-2003-14621).
---------------------------------------------------------------------------

    In response to the 2005 SAFETEA-LU mandate, NHTSA undertook a 
multi-phase research study of seat belt warnings. NHTSA published 
several reports on these studies. Three are particularly relevant to 
this's NPRM. The first is a large-sample (approximately 40,000 
observations) national observational study on the effectiveness of 
front seat belt warnings.\77\ The study covered several states in 
different parts of the country. The vehicles in the study sample had a 
wide variety of seat belt warning

[[Page 61685]]

systems. These included warning systems that had only the minimum 
features required by FMVSS No. 208, as well as twenty different 
enhanced warning systems. Because of the detail of the data gathered 
(e.g., occupant demographic and vehicle-specific information), the 
analysis was able to control for confounding factors. The second study 
uses an experimental or focus-group-based approach to study consumer 
acceptance as well as effectiveness.\78\ The third report summarized 
and extended the analyses from the previous two reports.\79\ This 
series of research studies shows, among other things, that the presence 
of an enhanced front seat belt reminder system increased front outboard 
passenger seat belt use by about 3 to 4 percentage points more than in 
vehicles with only a driver seat belt warning system meeting the 
minimum requirements in S7.3.
---------------------------------------------------------------------------

    \77\ Mark Freedman et al. The Effectiveness of Enhanced Seat 
Belt Reminder Systems Draft Report: Observational Field Data 
Collection Methodology and Findings. 2007. DOT HS-810-844. 
Washington, DC: National Highway Traffic Safety Administration.
    \78\ N. Lerner et al. 2007. Acceptability and Potential 
Effectiveness of Enhanced Seat Belt Reminder System Features. DOT HS 
810 848. Washington, DC: National Highway Traffic Safety 
Administration [hereinafter DOT 2007 Acceptability Study].
    \79\ DOT 2009 Belt Warning Study, supra note 36.
---------------------------------------------------------------------------

    In 2015 the agency completed an additional report on a study of the 
effectiveness and consumer acceptance of rear seat belt warnings.\80\ 
This study utilized a telephone survey of the drivers of vehicles with 
and without rear seat belt warning systems. The study found that 
overall, drivers of vehicles with a rear seat belt warning system were 
satisfied with the system and noticed an increase in rear seat belt 
use. For example, among drivers of vehicles with a rear seat belt 
warning, approximately 80% were satisfied with the system and 65% 
reported that the rear seat belt warning made it easier to encourage 
rear seat passengers to buckle up. About one-quarter of drivers (24%) 
of vehicles equipped with a rear seat belt warning system noticed an 
increase in rear seat belt use. When asked about their experience with 
the change of seat belt buckle status alert, close to half of the 
drivers of vehicles with a rear seat belt warning system (49%) said 
that their system had indicated, within the past year, that a passenger 
had unfastened his/her seat belt. Overall, of those who reported 
experiencing a change of seat belt status alert (49%), over three-
quarters of these drivers (77%) said that the unbuckled passenger 
eventually did refasten her seat belt, either on her own or at the 
driver's request.
---------------------------------------------------------------------------

    \80\ Paul Schroeder & Melanie Wilbur. 2015. Survey of Principal 
Drivers of Vehicles with a Rear Seat Belt Reminder System. 
Washington, DC: National Highway Traffic Safety Administration.
---------------------------------------------------------------------------

    In 2021, NHTSA published an update of the 2009 Belt Warning 
Study.\81\ The purpose of the report was to examine the front seat belt 
warning system features associated with greater effectiveness in 
increasing seat belt use. Because of limitations with the collected 
data, the findings of the report were relatively limited. However, the 
report found (consistent with the earlier research) that ``systems with 
sound, icon, and text had generally higher seat belt use rates than 
systems without all of these features.''
---------------------------------------------------------------------------

    \81\ Polson, A., Lerner, N., Burkhardt, E., Piesse, A., Zador, 
P., & Janniello, E. (2021, October). Enhanced seat belt reminder 
systems: An observational study examining the relationship with seat 
belt use (Report No. DOT HS 812 808). National Highway Traffic 
Safety Administration, Pg. 40.
---------------------------------------------------------------------------

    The results of this research are discussed in more detail 
throughout the preamble. The relevant research reports have also been 
placed in the docket for this rulemaking.

VI. Safety Need

    As noted earlier, rear seat belt use has consistently been lower 
than front seat belt use. NHTSA estimated the target populations for 
rear and front outboard passenger seat belt warnings, as well as the 
effectiveness of the warnings. This section provides a summary of these 
estimates. For additional discussion of the methodology used to derive 
these estimates, see the discussion in the Preliminary Regulatory 
Impact Analysis as well as the studies placed in the docket.
    To estimate the target populations for the rear and front passenger 
seats--that is, the number of unrestrained occupants who could be 
expected to potentially benefit from the proposed seat belt warning 
requirements--NHTSA examined data from the Fatality Analysis Reporting 
System (FARS) \82\ and the National Automotive Sampling System (NASS) 
Crashworthiness Data System (CDS) \83\ from 2011 to 2015. Because seat 
belts are effective at preventing deaths and injuries in all types of 
motor vehicle crashes,\84\ the target populations include fatalities 
and injuries from different crash modes. We examined fatalities and 
injuries for occupants in passenger cars, trucks, buses, and MPVs with 
a GVWR of 4,536 kg (10,000 lb) or less (the vehicles [with some 
exceptions] to which the proposed requirements would apply). We 
adjusted these to account for future decreases in fatalities and 
injuries projected to occur in the absence of the proposed requirements 
due to the introduction of other mandatory safety technologies (e.g., 
electronic stability control, ejection mitigation side curtain air 
bags).
---------------------------------------------------------------------------

    \82\ See NHTSA, NCSA Reports and Publications, https://www.nhtsa.gov/FARS. FARS contains data on a census of fatal traffic 
crashes within the 50 States, the District of Columbia, and Puerto 
Rico. To be included in FARS, a crash must involve a motor vehicle 
traveling on a traffic way customarily open to the public, and must 
result in the death of an occupant of a vehicle or a non-occupant 
within 30 days of the crash.
    \83\ The CDS target population is defined as police-reported 
motor vehicle traffic crashes involving at least one passenger car, 
pickup, van, or SUV (also called CDS applicable vehicles) that was 
towed from the scene due to damage.
    \84\ DOT Lives Saved Study at 106 (front seats); Id. at 112 
(rear seats). Seat belts are less effective in severe near-side 
impacts or other catastrophic crashes. Id. at 112.
---------------------------------------------------------------------------

    Based on FARS and NASS-CDS data from 2011 to 2015, on average 1,002 
unrestrained rear occupants were killed in crashes and 7,821 were 
injured annually.\85\ After adjusting these to account for future 
decreases in fatalities and injuries projected to occur in the absence 
of the proposed requirements due to the introduction of other mandatory 
safety technologies, there were, on average, 475 fatalities and 7,036 
injuries to unrestrained rear seat occupants each year. This is the 
overall target population for the proposed rear seat belt warning 
requirements.
---------------------------------------------------------------------------

    \85\ See PRIA, Appendix D.
---------------------------------------------------------------------------

    Turning to the target population for the driver and front outboard 
passenger seat, from 2011 to 2015, annually an average of 7,503 
unrestrained drivers were killed in crashes and an average of 1,453 
unrestrained front outboard passenger seat occupants were killed in 
crashes and 63,436 unrestrained drivers and front outboard passenger 
occupants were injured.\86\ After adjusting these to account for future 
decreases in fatalities and injuries projected to occur in the absence 
of the proposed requirements due to the introduction of other mandatory 
safety technologies, there were, on average, 6,733 fatalities and 
47,952 injuries to unrestrained front outboard seat occupants each 
year. This is the overall target population for the proposed front 
outboard passenger seat belt warning requirements.
---------------------------------------------------------------------------

    \86\ See PRIA, Appendix D.
---------------------------------------------------------------------------

VII. ANPRM

    On September 27, 2019, in accordance with the grant of the petition 
from Public Citizen and Advocates for Highway and Auto Safety and 
continuing with the proceeding that MAP-21 required to be initiated, 
NHTSA published an ANPRM for requiring rear seat belt warning 
systems.\87\ The ANPRM sought

[[Page 61686]]

comment on a variety of issues related to a requirement for a rear seat 
belt warning system, including potential requirements for such systems, 
the vehicles to which they should apply, their effectiveness, the 
likely consumer acceptance, and the associated costs and benefits. It 
also sought comment on removing the 8-second maximum duration for the 
driver's seat belt warning specified in FMVSS No. 208 S7.3 to reflect 
MAP-21's repeal of the statutory limitation that was the basis for this 
provision.
---------------------------------------------------------------------------

    \87\ 84 FR 51076 (Sept. 27, 2019).
---------------------------------------------------------------------------

    The comment period closed on November 26, 2019. NHTSA received 45 
comments: five comments from vehicle manufacturers; two from school 
transportation associations; two from vehicle manufacturer 
associations; seven from safety advocacy groups; seven from automotive 
industry suppliers and trade associations; one comment each from a 
foreign country, insurance institute, consumer program, and bus 
manufacturer; and eighteen comments from individual members of the 
public.
    Most commenters, including safety advocates, vehicle manufacturers 
and suppliers, and individual members of the public, supported a rear 
seat belt warning requirement. Some commenters (including a bus 
manufacturer, a bus supplier, an association of school bus operators, 
and some individual commenters) recommended that the requirements not 
apply to heavy vehicles such as buses or school buses, citing concerns 
with installation, costs, the driver's role, and maintenance.
    Vehicle manufacturers and suppliers commented that the requirements 
should harmonize with ECE R16, while some other commenters 
(predominantly safety advocacy groups) supported departures from the 
ECE R16 requirements, arguing that harmonization should not come at the 
expense of safety. Thus, while most commenters supported requiring a 
visual warning on vehicle start-up and an audio-visual change-of-status 
warning for a belt that is unfastened when the vehicle is moving, some 
commenters favored requiring enhanced features such as an audio-visual 
warning on vehicle start-up and occupant detection.
    A few commenters (Advocates, Kids and Cars, Center for Auto Safety) 
pointed out the delays with this rulemaking and the urgency for a final 
rule. Most vehicle manufacturers supported removing the upper limit on 
the duration of the audible warning for the driver's seat belt.

VIII. NHTSA's Statutory Authority

    NHTSA is proposing this's NPRM pursuant to its authority under the 
National Traffic and Motor Vehicle Safety Act.
    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.\88\ ``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 an accident, and includes nonoperational safety of a motor 
vehicle.'' \89\ ``Motor vehicle safety standard'' means a minimum 
performance standard for motor vehicles or motor vehicle equipment.\90\ 
When prescribing such standards, the Secretary must consider all 
relevant, available motor vehicle safety information.\91\ 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.\92\ The responsibility for 
promulgation of Federal motor vehicle safety standards is delegated to 
NHTSA.\93\ In making the proposals in this's NPRM, the agency carefully 
considered all the aforementioned statutory requirements. They are 
discussed in more detail throughout the preamble and in the regulatory 
analyses. In addition, MAP-21 directed NHTSA to initiate a rulemaking 
to require a seat belt warning for the rear seats in motor vehicles 
(see Section III, Regulatory and Legislative History).
---------------------------------------------------------------------------

    \88\ 49 U.S.C. 30111(a).
    \89\ 49 U.S.C. 30102(a)(9).
    \90\ Section 30102(a)(10).
    \91\ Section 30111(b)(1).
    \92\ Section 30111(b)(3)-(4).
    \93\ See 49 CFR 1.95.
---------------------------------------------------------------------------

IX. Overview of Proposed Requirements

    As previously mentioned, this NPRM proposes amending the existing 
seat belt warning provisions in FMVSS No. 208. This proposal has two 
main components. The first proposes requiring a seat belt reminder for 
the rear seats. The second proposes changes and enhancements to the 
seat belt warning requirements for the front outboard seats. These 
proposed requirements would apply to passenger cars and trucks, buses 
(except school buses), and multipurpose passenger vehicles with a GVWR 
of 4,536 kg (10,000 lb) or less.

Rear Seat Belt Reminder Requirements

    The first component of this NPRM is a set of proposed requirements 
for a seat belt warning for rear seats. The proposed requirements have 
four main elements.
     Visual warning on vehicle start-up to inform the driver of 
the status of the rear seat belts. We propose three different 
compliance options for the rear seat belt warning system. The first 
would require the system to indicate how many or which rear seat belts 
are in use (the ``positive-only'' option). The second would require the 
system to indicate, for the occupied rear seats, how many or which rear 
seat belts are not in use (the ``negative-only'' option). The third 
would require the system to indicate, for the occupied rear seats, how 
many or which rear seat belts are in use and how many or which rear 
seat belts are not in use (the ``full-status'' option). Certain 
features would be required of all the options. Each system would have 
to provide a continuous or flashing visual warning, consisting of 
either icons or text, visible to the driver. The visual warning would 
have to last for at least 60 seconds, beginning when the vehicle's 
ignition switch is moved to the ``on'' or ``start'' position. The 
negative-only and full-status compliance options would require that the 
rear seats be equipped with a belt latch sensor and an occupant 
detection system (which facilitates these more-informative warnings), 
while the positive-only option would only require that the rear seats 
be equipped with a belt latch sensor.
     Audio-visual change-of-status warning. We propose an 
audio-visual warning whenever a fastened rear seat belt is unfastened 
while the ignition switch is in the ``on'' or ``start'' position and 
the vehicle's transmission selector is in a forward or reverse gear. 
The warning would have to last for at least 30 seconds. We do not 
propose any requirements for the volume or tone of the warning. The 
intent of this warning is to alert the driver or other occupants of a 
change in belt status during a trip. The warning would not be required 
if a door is opened, which would be the case if a rear passenger 
unfastened their belt in order to exit the vehicle.

[[Page 61687]]

     Requirements related to electrical connections. Readily 
removable rear seats would be required to either automatically connect 
the electrical connections when the seat is put in place, or, if a 
manual connection is required, the connectors must be readily-
accessible. Further, vehicles utilizing the negative-only compliance 
option would be required to provide a visual warning to the driver if a 
proper electrical connection has not been established for a readily 
removable rear seat.
     Owner's manual requirements. We propose that the vehicle 
owner's manual (which includes information provided by the vehicle 
manufacturer to the consumer, whether in digital or printed form) 
describe the warning system's features, including the location and 
format of the visual warnings. We also propose that the owner's manual 
(which includes information provided by the vehicle manufacturer to the 
consumer, whether in digital or printed form) include instructions on 
how to make any manual electrical connections for readily removable 
seats.

Front Outboard Seat Belt Warning Requirements

    We propose several changes and enhancements to the seat belt 
warning requirements for the front outboard seats:
     Audio-visual warning on vehicle start-up for front 
outboard passenger seat. Currently, only the driver's seat is required 
to have a seat belt warning, although almost all vehicles now provide a 
seat belt warning for the front outboard passenger seat as well. 
Accordingly, we propose to require a seat belt warning for the front 
outboard passenger seat. In addition, for an ADS-equipped vehicle that 
has no manually-operated driving controls, we are proposing that the 
front passenger warning apply to ``any'' front outboard passenger.
     Increasing the duration of the audio-visual warning on 
vehicle start-up. We propose enhancing the front seat belt warning 
duration by requiring an audio-visual warning that remains active until 
the seat belt at any occupied front outboard seat is fastened. We are 
proposing this in light of a variety of factors, including the increase 
in roadway fatalities, the lack of improvement of front seat belt use 
rates, and the fact that the audio-visual warnings with which vehicle 
manufacturers are currently equipping vehicles significantly exceed the 
4-second regulatory minimum (including a non-trivial share of currently 
sold vehicles with an indefinite-duration reminder). Vehicle 
manufacturers can adjust warning signal characteristics (such as 
frequency and volume) to make the warning both effective and acceptable 
to consumers. We are also proposing some additional requirements for 
the warning related to increasing the duration (for example, specifying 
at least a 20 percent duty cycle for the warning).
     Audio-visual change-of-status warning. We also propose to 
require an audio-visual change-of-status warning whenever a front 
outboard passenger seat belt is unbuckled during a trip (unless a front 
door is opened, to account for an occupant unfastening the belt to exit 
the vehicle). The warning would be required to remain active until the 
seat belt is refastened.
     Driver seat belt warning for medium-sized buses. FMVSS No. 
208 currently does not require a driver seat belt warning for medium-
sized buses (roughly, buses that weigh between 3,855 kg (8,500 lb) and 
4,536 kg (10,000 lb)). We are now proposing to require that these buses 
be equipped with a driver seat belt warning. NHTSA is unaware of any 
such buses that do not already have an FMVSS No. 208-compliant driver 
seat belt warning.

Effective Date

    We propose an effective date of the first September 1 that is one 
year after the publication of the final rule for the front seat belt 
warning system requirements and the first September 1 that is two years 
after the publication of the final rule for the rear seat belt warning 
system requirements, with optional early compliance. For example, if 
the final rule were published on October 1, 2022, the effective date 
would be September 1, 2024 for the front seat belt warning system 
requirements and September 1, 2025 for the rear seat belt warning 
system requirements. Consistent with 49 CFR 571.8(b), multi-stage 
manufacturers and alterers would have an additional year to comply.

X. Proposed Rear Seat Belt Warning 94
---------------------------------------------------------------------------

    \94\ Comments are from the ANPRM unless otherwise noted. As 
discussed in more detail in the regulatory alternatives section, 
many commenters (OEMs and trade groups) generally recommended 
harmonizing with R16 and/or other NCAP programs. In the following 
sub-sections, we include comments that specifically recommended 
harmonizing with R16 or Euro NCAP with respect to the particular 
issue being discussed.
---------------------------------------------------------------------------

A. Overview

    The proposed rear seat belt warning requirements have four main 
components: a visual warning on vehicle start-up to alert and inform 
the driver of the status of the rear seat belts; an audio-visual 
change-of-status warning when a rear seat belt is unbuckled during a 
trip; requirements for the electrical connections for readily removable 
seats; and owner's manual requirements. We also propose requirements 
for several characteristics of this warning, such as duration and 
triggering conditions. We also discuss related issues such as hardening 
the system against user circumvention, consumer acceptance, and 
technological and economic feasibility.
    The proposed changes would apply to all rear designated seating 
positions in passenger cars, trucks, buses (except school buses), and 
MPVs with a GVWR of 4,536 kg (10,000 lb) or less.

B. Applicability

    The ANPRM sought comment on the vehicles to which a rear seat belt 
warning requirement should apply. The current FMVSS No. 208 generally 
requires rear seat belts in passenger cars, trucks, MPVs, buses less 
than 10,000 lb, over-the-road buses between 10,000 lb and 26,000 lb, 
and buses greater than 26,000 lb (except school, perimeter-seating, and 
transit buses). We observed that high-occupancy vehicles might pose 
challenges for implementing a rear warning system due to the potential 
complexities of the visual signal, number of seats, and other issues. 
At the same time, such vehicles could be at least as likely--if not 
more likely--to have rear occupants. With respect to school buses, a 
rear seat belt warning requirement might place additional cost burdens 
on school systems, potentially leading to reductions in school bus 
service, with a concomitant increased risk to students.\95\ We also 
noted that school buses utilize compartmentalization to reduce the risk 
of crash injury, even to the unbelted.
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    \95\ See 76 FR 53102 (Aug. 25, 2011) (denial of a petition for 
rulemaking to mandate the installation of three-point seat belts for 
all seating positions on all school buses).
---------------------------------------------------------------------------

    The ECE R16 rear belt warning requirements apply to M1 and N1 
vehicle categories (passenger cars, multipurpose passenger vehicles, 
vans, pick-ups and light trucks), with exemptions for ambulances, 
hearses, and motor-caravans, as well as for all seats for vehicles used 
for transport of persons with disabilities, vehicles intended for use 
by the armed services, civil defense, fire services and forces 
responsible for maintaining public order.\96\
---------------------------------------------------------------------------

    \96\ Sec.  8.4.1.2.

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[[Page 61688]]

Comments
    Advocates commented that the requirements should apply, at a 
minimum, to all passenger vehicles, and should apply in all vehicles in 
which data indicates belt non-use is occurring. Freedman Seating 
Company (a manufacturer of seating for the transportation industry) 
favored a requirement for all vehicles (and, presumably, seating 
positions) requiring Type 2 seat belts.\97\ A number of commenters 
recommended that the requirements harmonize with R16. Two commenters 
stated that, consistent with ECE R16-07, vehicles such as ambulances, 
hearses, and police cars should be exempt from any requirements. Two 
commenters similarly stated that the rule should only apply to vehicles 
under 10,000 pounds GVWR (with some specific exclusions for certain 
vehicle types). A commenter argued that while there might be benefits 
to a requirement for commercial vehicles and buses, it could pose 
considerable challenges for those vehicles, so any requirements for 
larger vehicles should be considered in a separate rulemaking.
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    \97\ A Type 1 seat belt assembly is a lap belt for pelvic 
restraint, and a Type 2 seat belt assembly is a combination of 
pelvic and upper torso restraints (3-point belt). Type 2 belts are 
required for most rear seats in passenger cars. S4.1.5.5. Type 2 
belts are also required for most rear seats on buses required to 
have rear seat belts. Type 2 belts are also required on most rear 
seats in trucks and MPVs less than or equal to 10,000 lb. Type 2 
belts generally are not required on side-facing seats.
---------------------------------------------------------------------------

    We also received several comments specifically about applicability 
to buses. One comment stated that seat belt reminder systems should be 
included in vehicles 10,000 lb and under, including high-occupancy 
vehicles such as 15-passenger vans and school buses, given the 
likelihood of vulnerable (e.g., children) rear seat passengers and the 
difficulty for the driver to determine if occupants are belted. Other 
commenters opposed a requirement for some or all buses. A commenter 
opposed requirements for any buses based on what it characterized as 
the complexity, cost, potential for driver distraction, and lack of 
data supporting effectiveness.\98\ A commenter stated that rear seat 
belt warnings should not be required in motorcoaches; \99\ while 
technically feasible, such a requirement would be costly and not 
suitable. The commenter's concerns were similar to those that detailed 
for school buses (see below).
---------------------------------------------------------------------------

    \98\ Blue Bird's comment was unclear, because it also 
specifically commented that it was opposed to any changes which 
expand the requirements of FMVSS No. 208 for buses with a GVWR 
greater than 3,855 kg (8,500 lb), including the proposed requirement 
for rear passenger seat belt warning systems.
    \99\ We assume that this refers to traditional motorcoaches 
which are over 10,000 lb.
---------------------------------------------------------------------------

    Several commenters argued that school buses should be excluded from 
any requirements. They made a variety of arguments on this point.
    The commenters argued that a requirement for school buses would be 
prohibitively expensive. One commenter stated that it could dissuade 
pupil transporters from voluntarily equipping large buses with seat 
belts, as well as provoke objections to laws that require them. Several 
comments questioned the technical feasibility and the potential for 
malfunctions and false alarms. A commenter stated that because of the 
complexity of any system required for a vehicle with a large number of 
rear seating positions, improper detection is a real possibility. Two 
commenters similarly said that the sensors might not be sophisticated 
enough to deal with the variations found in the school bus operating 
environment, because children that ride in school buses are of varying 
ages and sizes, with NSTA noting the possibility of false alarms. A 
commenter stated that the school bus interior is a harsh environment 
and the necessary wiring and connections are subject to failure by 
exposure or tampering; this failure for hardwired systems could be 
eliminated through use of wireless technology, but transmitting devices 
are also subject to failure, and require power. However, some 
commenters noted that rear warnings for school buses may be technically 
feasible and are, to some extent, currently available.
    Two commenters also raised potential unintended consequences of 
school bus driver distraction. A commenter brought up that driver 
distraction is perhaps the greatest concern for the implementation of 
warning device technology in school buses. The primary function of the 
school bus driver is to safely transport the student passengers; the 
bus driver must be able to fully focus on driving, so each activation 
of a warning would require a bus driver to transfer focus to the 
display source to read the data, understand the data, then interpret 
the data to the exact student/location in the bus. At that point, the 
driver would need to direct the student to buckle up if that is the 
actual need. This situation could occur simultaneously with several 
students. In driving situations with high-density urban traffic or 
high-speed rural two-lane roads with much commercial vehicle traffic, 
the potential for a crash could significantly increase.
    A couple of commenters questioned the ability of school bus drivers 
to ensure that student occupants use the seat belts. A commenter 
questioned what a driver faced with a seat belt warning should do: 
Would the driver be required to walk the aisle like an airplane flight 
attendant inspecting the entire bus and requiring students to buckle 
up? Would the driver be required to refuse to move the bus until all 
belts are buckled? The commenter also questioned whether it is the 
responsibility of the driver or the passenger to obey any applicable 
state law (along with parental and school information and 
encouragement) and ensure the belt is fastened. Another commented 
similarly stated that the driver's ability to ensure seat belt use is 
limited; the student passengers' failure to comply often comes after 
repeated requests to do so from school bus drivers or aides. A few 
commenters also had concerns about potential legal liability for 
operators and drivers. A commenter stated that school districts would 
need to determine if the failure of a warning system to properly 
function would require that the seating position be rendered unusable, 
and another commenter said that it was unclear if the presence of a 
seat belt warning system would make the driver legally liable in a 
crash for injuries to unbelted students. The commenter further wondered 
whether the addition of such a system would force school systems to 
hire bus monitors to supervise belt use, adding a significant cost to 
state and local budgets. Along these lines, the commenter recommended a 
hold-harmless provision in the regulations to cover school bus 
operators for instances where a student passenger evades a seat belt 
restraint system and sustains injuries.
    Related to this, two commenters mentioned the possibility of 
circumvention in school buses. One commenter noted the ability of 
passengers to defeat the systems (either intentionally or 
unintentionally); sophisticated sensor design would be required to warn 
the driver of non-use in these cases. Another commenter said that an 
occupant could buckle the belt behind him/her, thus turning off the 
alarm without having complied with the purpose of the alarm.
    A commenter stated that a seat belt warning on school buses would 
lead to routing delays, due to additional time required at each stop to 
ensure that students were belted. The commenter also noted the 
potential effects of stopped buses (especially during rush hours). 
Another commenter said that system malfunctions would result in a 
school bus being removed from service and raised the possibility of a 
malfunction occurring mid-trip, which

[[Page 61689]]

would present the operator the issue of whether to continue operating 
the bus or not.
Agency Response
    This proposal applies to all rear designated seating positions in 
passenger cars and all rear designated seating positions certified to a 
compliance option requiring a seat belt in trucks, buses, and MPVs with 
a GVWR of 4,536 kg (10,000 lb) or less, except for school buses and law 
enforcement vehicles. We propose to apply the proposed requirements to 
these categories of vehicles because these vehicles are required to 
have seat belts at all rear designated seating positions and (except 
for some buses) a seat belt warning for the driver's seat.\100\ We note 
that some types of trucks and MPVs (motor homes, walk-in van-type 
trucks, vehicles designed to be sold exclusively to the U.S. Postal 
Service, or vehicles between 8,500-10,000 lbs carrying a chassis-mount 
camper) \101\ and over-the-road buses that are also prison buses \102\ 
are not required to have rear seat belts. The proposed applicability is 
largely consistent with ECE R16, except that we are not proposing to 
exempt special-purpose vehicle types such as ambulances because they 
are typically customized after first sale.\103\
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    \100\ Buses with GVWRs greater than 8,500 lb and less than or 
equal to 10,000 lb are currently not required to have a driver's 
seat belt warning. See FMVSS 208, S4.4.3.1. We propose to close this 
loophole. See Section XI.B.
    \101\ S4.2.7.1.
    \102\ S4.4.3.3; S4.4.5.1.
    \103\ See 49 U.S.C. 30112(b)(1) (a FMVSS does not apply to, 
among other things, ``the sale, offer for sale, or introduction or 
delivery for introduction in interstate commerce of a motor vehicle 
or motor vehicle equipment after the first purchase of the vehicle 
or equipment in good faith other than for resale'').
---------------------------------------------------------------------------

    We believe it is particularly important to include vehicles with a 
GVWR greater than 3,855 kg (8,500 lb), but less than or equal to 4,536 
kg (10,000 lb)--including buses other than school buses--because this 
includes high occupancy vehicles (e.g., large capacity passenger vans 
and large sport utility vehicles [SUVs]).\104\ We also believe an 
increasing number of large trucks and vans are used as personal 
vehicles and are not solely used for work-related purposes. In 
addition, multiple rear seats or rows make it more difficult for the 
driver to ascertain rear seat belt use, so a warning could prove 
especially useful in these vehicles. We also recognize that the intent 
of the MAP-21 mandate is to improve protection for rear occupants; 
given the proven benefits of seat belts, we tentatively believe the 
warning should be broadly applied. We acknowledge that vehicles with a 
larger number of rear seats may encounter visual signal complexities. 
Accordingly, our intent is to propose performance requirements that 
provide manufacturers with the flexibility to design a warning system 
that is appropriate for each vehicle type. We chose to limit the 
application of the passenger seating requirements to light-duty 
vehicles (less than or equal to 10,000 lb). Several commenters were all 
in agreement with excluding vehicles over 10,000 lb; it is consistent 
with the petition and with the applicability of the current seat belt 
warning system requirements.
---------------------------------------------------------------------------

    \104\ Fifteen-passenger vans are classified as buses under the 
FMVSS because they are designed for carrying more than ten persons. 
See 49 CFR 571.3 (``Bus means a motor vehicle with motive power, 
except a trailer, designed for carrying more than 10 persons.'') 
(italics in original).
---------------------------------------------------------------------------

    We have tentatively decided to exclude all school buses (including 
those weighing under 10,000 lb [small school buses]) because of 
practicability issues. First, the agency is concerned about the costs 
to school systems, which could lead to reductions in school bus 
service, resulting in greater risk to students. Second, we are 
concerned about the burdens such systems might place on the driver. For 
example, with a rear seat belt warning system without occupant 
detection (the minimum compliance option that we are proposing in this 
NPRM), the school bus driver would have to verify that all the 
passengers are using their seat belts based on the system's visual 
signal that identifies how many or which rear seat passengers are 
belted. We tentatively agree with the commenters who argued that is not 
practicable. This concern might be mitigated, in part, by a more robust 
system utilizing occupant detection, but we do not believe that would 
be practicable at this time.\105\ Third, school buses of all sizes 
offer passengers compartmentalization protection to reduce the risk of 
crash injury, even to the unbelted. Such protection is not offered in 
other vehicles. Finally, we note various other concerns raised by the 
commenters and summarized above, including the possibility of school 
buses being out of service due to malfunctioning reminder systems, and 
potential liability issues for school districts.
---------------------------------------------------------------------------

    \105\ More discussion of occupant detection systems is provided 
in Section XIV.B.
---------------------------------------------------------------------------

    Law enforcement vehicles would also be exempt from the proposed 
requirements because of concerns with practicability: the rear seats 
are mainly used to transport passengers that are under arrest and 
normally handcuffed, so if the policy of the police agency is that 
prisoners be transported with their seat belts fastened then the 
officer would be responsible for fastening the seat belt around the 
prisoner(s) and thus would already be aware of the belt status of the 
rear seat occupants. The term ``law enforcement vehicle'' is already 
defined in FMVSS No. 208 to mean ``any vehicle manufactured primarily 
for use by the United States or by a State or local government for 
police or other law enforcement purposes.''
    We seek comment on our proposed applicability requirements.

C. Requirements

    This NPRM proposes a visual warning on vehicle start-up and an 
audio-visual change-of-status warning if a belt is unbuckled during a 
trip. We also propose a variety of requirements with respect to the 
warning triggering conditions, duration, telltale, and electrical 
connections, among other things.
1. Visual Warning on Vehicle Start-Up
    This NPRM proposes a visual warning to alert and inform the driver, 
upon vehicle start-up, to the status of the rear seat belts. We also 
propose minimum performance requirements for several aspects of this 
warning.
a. Compliance Options for the Type of Information Conveyed
    The ANPRM sought comment on whether NHTSA should require a warning 
at the start of the trip, whether such a warning should be visual-only 
or audio-visual, and what type of information the visual warning should 
convey. NHTSA identified three potential types of warnings. One would 
require the system to indicate how many or which rear seat belts are in 
use (a ``positive-only'' system). The second would require the system 
to indicate, for the occupied rear seats, how many or which rear seat 
belts are not in use (``negative-only''). The third requires the system 
to indicate, for the occupied rear seats, how many or which rear seat 
belts are in use and how many or which rear seat belts are not in use 
(``full-status''). The second and third types of warnings identified 
would require that the system be capable of determining which rear 
seating positions are occupied (i.e., would require an occupant 
detection system). NHTSA also sought comment on whether some or all of 
the compliance options should require occupant detection.
    ECE R16 requires a visual warning at the start of a trip, but not 
an audible

[[Page 61690]]

signal.\106\ The visual warning must remain active until none of the 
belts that triggered the warning are unfastened, the seat(s) which 
triggered the warning are no longer occupied, or 60 seconds has 
elapsed.\107\ The visual warning must ``indicate at least all rear 
seating positions to allow the driver to identify, while facing forward 
as seated on the driver seat, any seating position in which the safety-
belt is unfastened.'' \108\ Occupant detection is not required, but in 
vehicles that do have occupant detection the warning does not need to 
indicate unfastened belts for unoccupied seating positions.\109\ This 
warning may be canceled by the driver.\110\
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    \106\ Section 8.4.4.1; Section 8.4.2.3.1.
    \107\ Section 8.4.2.3.1; Sec.  8.4.2.3.2.
    \108\ Section 8.4.4.2.
    \109\ Section 8.4.4.2.
    \110\ Section 8.4.4.3.
---------------------------------------------------------------------------

    Euro NCAP's rating protocol also requires a visual warning at the 
start of a trip. The requirements are similar to ECE R16. Euro NCAP's 
rating protocol does not require occupant detection but incentivizes 
systems that use occupant detection by awarding additional points for 
this feature. For systems without occupant detection, the visual signal 
must show belts in use and not in use.\111\ For systems with occupant 
detection, the visual signal does not need to indicate the number of 
seat belts in use or not in use, but the signal must remain active as 
long as the seat belts remain unfastened on any of the occupied seats 
in the rear; \112\ no visual signal is required if no rear occupants 
are detected.\113\ Systems with occupant detection must also provide a 
30-second audible signal at the start of the trip before specified 
speed or distance thresholds have been crossed.\114\ Alternatively, if 
occupant detection is provided the manufacturer may use the same 
warning strategy as specified for the front seats.\115\
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    \111\ Section 3.4.3.1.4.
    \112\ Section 3.4.3.1.3.
    \113\ Section 3.4.3.1.1.
    \114\ Section 3.4.3.2.3. The thresholds are (at the choice of 
the OEM) either a forward speed of 25 km/h or forward motion for 500 
m.
    \115\ Section 3.4.3.2.3. For front seat belts, the assessment 
protocol requires both a visual and an audible warning signal (see 
Section 3.4.2). The visual signal must remain active until the seat 
belt is fastened. The audible signal has two stages, an initial and 
final audible signal, which have different onset criteria. The 
initial audible signal must not exceed 30 seconds and the final 
audible signal must be at least 90 seconds. To prevent unnecessary 
signals, the system must also be capable of detecting whether the 
front passenger seats are occupied.
---------------------------------------------------------------------------

Comments
    Most commenters explicitly endorsed a warning on start-up, and none 
opposed it, although the comments differed on whether it should have an 
audible component. Two comments recommended harmonizing with the ECE 
R16 requirement for a visual-only warning on start-up. A commenter 
stated that NHTSA should provide flexibility in terms of the type of 
information that is required to be communicated by the reminder system, 
including positive-only, negative-only, and full-status systems, with 
consideration for both occupant-detection and non-occupant-detection 
centric approaches. Based on the definitions provided within the ANPRM, 
the baseline standard for R16 could be met through a non-occupant 
detection, positive-only system, but would not prohibit additional 
technology features to provide additional functionality. Another 
commenter agreed that positive-only, negative-only, and full-status 
systems each could have strengths and limitations; the priority should 
be that all of these variations effectively allow the driver to 
identify which seats are unfastened (in the case without occupant 
detection), or if any occupied seats are unfastened (with occupant 
detection). The commenter noted that R16 does not establish such 
definitions of systems, but rather specifies the base requirement that 
the driver should be able to identify which seats are unfastened. The 
comment stated that NHTSA should not set criteria too broadly, which 
could restrict manufacturers to implementing a full-vehicle display, 
even if occupant detection is applied, in which case a single seat belt 
telltale indicator is sufficient.
    Three commenters recommended a visual-only warning. A commenter 
stated that a visual warning, such as a telltale, should exist as an 
initial warning, and a combination of audible and visual warnings could 
exist as a ``second-level'' warning. Another commenter stated that 
visual displays are efficient at conveying information that is complex, 
that deals with locations in space, or that does not require immediate 
action. The comment stated that, while audio-visual warnings are more 
effective than visual-only warnings, visual displays are less intrusive 
and perceived as less annoying than audible warnings, so that a visual-
only warning would minimize the impact of false warnings that could 
negatively impact consumer acceptance. The commenter also stated that, 
while visual displays alone have not been found to be effective for 
motivating occupants to use a seat belt, the driver may use this 
information to encourage unbuckled rear occupants to use a seat belt.
    Several commenters favored requiring an audio-visual warning at the 
start of the trip. Four commenters supported the specification of the 
most effective warnings and noted that audio-visual warnings are more 
effective than visible warnings alone. Two commenters stated that a 
visual-only warning would be easily missed by a driver who is focused 
on driving safely.
    Three commenters recommended requiring a ``negative'' warning with 
occupant detection. A commenter said that such systems would reduce 
false signals and annoyance. Another commenter similarly supported a 
warning on startup and commented that while a positive-only warning 
icon at the start of a ride would be helpful, it would not be as 
valuable as a warning triggered by negative-only status as a way to 
change the behavior of those occupants who are lax or reluctant to 
buckle up.
Agency Response
    This rule proposes to require a visual warning (without an audible 
component) upon vehicle start-up. NHTSA decided to propose the three 
compliance options identified in the ANPRM for the type of information 
the warning must convey. Each proposed system has strengths and 
limitations. The positive-only system would be the least technically 
complex of the three proposed options. Since it would only need to 
detect whether a seat belt is in use, it would only require a seat belt 
latch sensor. With a positive-only system, the driver would need to 
determine how many rear seat occupants there are and then determine if 
that number equals the number of seat belts that are reported by the 
warning system as buckled. This compliance option would not necessitate 
occupant detection; we tentatively believe that there are still design 
and technological challenges associated with implementing occupant 
detection technology in rear seats (this is discussed in more detail in 
Section XIII, Regulatory Alternatives).
    The negative-only and full-status systems would provide the driver 
with more information, and thus might be more effective than the 
positive-only system for at least two reasons. First, they would 
directly inform the driver whether any rear seat occupants were 
unbuckled, without the driver having to compare the number or location 
of occupants and fastened belts. Second, as discussed in more detail 
below, warning systems equipped with occupant

[[Page 61691]]

detection are more amenable to audible warnings and enhanced warning 
features. However, we tentatively believe that systems such as these 
that provide a negative warning--that is, a warning for an unfastened 
belt--are only appropriate for systems utilizing occupant detection. 
This is because we tentatively believe that it is not appropriate to 
provide a warning for an unfastened seat belt at an unoccupied seat 
because such ``false positives'' could be a nuisance for the driver and 
might either desensitize the driver to the warning signal or lead them 
to circumvent or defeat the system--especially since the majority of 
trips do not have rear seat occupants. The proposal would therefore 
permit a warning for an unfastened belt only if the seating position 
were equipped with occupant detection. Accordingly, it would not, for 
example, permit a system without occupant detection that displayed the 
status of all the rear seat belts to be certified as a positive-only 
system coupled with a voluntary warning for unfastened seat belts.
    With respect to comments in favor of requiring audio-visual 
warnings, we agree that warnings with an audible component are 
generally more effective. However, requiring an audio-visual warning 
would necessitate requiring occupant detection because the resulting 
``false positives''--having an audible warning activate for an 
unfastened belt at an unoccupied seat--would annoy the driver and could 
decrease the effectiveness of the warning. Thus, this NPRM does not 
require an audible warning on startup. However, manufacturers would be 
free to provide an audible warning on startup if they so choose, 
especially if the vehicle is equipped with occupant detection in the 
rear. This approach harmonizes with R16 and Euro NCAP.
    We acknowledge that there are systems currently deployed in both 
the United States and Europe that would not comply with the proposed 
compliance options. In particular, manufacturers appear to be deploying 
systems without occupant detection that provide a warning for an 
unfastened belt. When the ANPRM was published, the rear seat belt 
warning systems in vehicles sold in the United States used what would 
be classified in this proposal as a positive-only warning system. Our 
current, preliminary review, however, indicates that manufacturers are 
now providing visual warnings that indicate unfastened seat belts, and 
not necessarily with occupant detection. For example, the visual 
warning displays on some MY2022 Honda and Porsche vehicles appear to 
indicate the status of all the rear seat belts, but the owner's manual 
does not indicate that the vehicle is equipped with occupant detection 
in the rear seats. This information is consistent with Honda's comment 
that the compliance options should allow the driver to identify which 
seats are unfastened (in the case without occupant detection).
    Similarly, it appears that, as suggested in the comments, European 
vehicle manufacturers are deploying systems that indicate seat belts 
that are fastened, seat belts that are not fastened, or the status of 
all rear seat belts, both with and--importantly--without occupant 
detection.\116\ For example, the MY 2021 Peugeot 3008 appears to have a 
system that indicates the status of all the rear seat belts but does 
not indicate in its owner's manual that it has occupant detection in 
the rear seats. Both ECE R16 and Euro NCAP appear to permit a broad 
range of systems, including those providing warnings for unfastened 
belts at unoccupied seats. R16 requires that the visual warning 
``indicate at least all rear seating positions to allow the driver to 
identify, while facing forward as seated on the driver seat, any 
seating position in which the safety-belt is unfastened.'' Euro NCAP 
similarly requires systems without occupant detection to provide a 
visual warning showing both the belts in use and not in use. 
Nevertheless, we tentatively believe that the proposed deviation from 
R16 and some current United States and European systems is warranted 
because we tentatively believe it is not appropriate to provide a 
warning for an unfastened belt at an unoccupied seat.
---------------------------------------------------------------------------

    \116\ Approximately 70% of Euro NCAP-tested vehicles had 
occupant detection in the rear seats.
---------------------------------------------------------------------------

    Although the three proposed compliance options are not identical to 
the R16 and Euro NCAP requirements, we believe that a system that 
complies with the proposed requirements could also comply with R16 and 
Euro NCAP. With respect to R16, each of the three proposed compliance 
options would ``allow the driver to identify, while facing forward as 
seated on the driver seat, any seating position in which the safety-
belt is unfastened.'' While the reference to an ``unfastened'' belt 
might be read to preclude a positive-only system--that is, it might be 
read to mean that the system must explicitly inform the driver of an 
unfastened belt, such as would be the case in the systems we are 
calling ``negative-only'' or ``full-status''--after reviewing the types 
of systems available in the European market we believe this is not the 
case. Similarly, the negative-only and full-status compliance options 
appear consistent with Euro NCAP because they would provide a warning 
for an unfastened seat belt at an occupied seat.\117\ However, the 
positive-only compliance option does not appear to be consistent with 
Euro NCAP because Euro NCAP requires that systems without occupant 
detection show the rear seat belts in use and not in use, and the 
positive-only compliance option would not permit a visual signal for an 
unfastened seat belt.\118\
---------------------------------------------------------------------------

    \117\ Section 3.4.3.1.3.
    \118\ See Euro NCAP section 3.4.3.1.4.
---------------------------------------------------------------------------

    NHTSA seeks comment on all of these issues. While we have 
tentatively concluded that the proposed compliance options would help 
mitigate false warnings and the possibly attendant consumer acceptance 
issues, we are considering altering the proposed compliance options to 
accommodate systems that are currently being deployed, or that 
manufacturers may wish to deploy in the future. For example, we are 
considering allowing visual warnings that indicate which seat belts are 
unfastened without occupant detection. We therefore seek comment on 
what visual warnings vehicle manufacturers are using in the United 
States and Europe and whether they employ occupant detection. We also 
seek comment on why vehicle manufacturers have decided to use visual 
warnings that indicate unfastened seat belts without the use of 
occupant detection and whether they have received complaints from 
consumers about false warnings, or requests to deactivate the system. 
Is there any consumer acceptance data to support or oppose allowing 
visual warnings that indicate unfastened seat belts without the use of 
occupant detection in the rear seats? We also seek comment on whether 
there are any other aspects of the proposed compliance options with 
which current or anticipated future systems would not comply. Is there 
a preferable set of options that is sufficiently objective to satisfy 
the Safety Act? NHTSA also seeks comment on how manufacturers interpret 
the R16 requirements, to the extent that the agency's characterization 
of them is contrary to industry understanding or practice. NHTSA also 
seeks comment on whether the proposed regulatory text is sufficiently 
objective and unambiguous.
b. Triggering Conditions
    In the ANPRM we indicated that requiring the warning at the 
beginning of each journey or trip the vehicle makes is intuitively 
appealing because it

[[Page 61692]]

would help assure that occupants are safely restrained prior to any 
potential vehicle crash. However, we sought comment on the possible 
advantages of delaying the warning to a time when the driver or 
occupants are less distracted and therefore might pay more attention to 
the warning.
    R16 requires that the visual warning activate when a belt is not 
fastened and the ignition or master control switch activated.\119\ Euro 
NCAP similarly requires that the warning start at the commencement of a 
journey when the ignition switch is engaged (whether or not the engine 
is running) and any of the rear belts are not fastened.\120\ However, 
Euro NCAP allows for short breaks in the journey (up to 30 seconds) to 
account for events such as engine stalling where the reminder is not 
required to start again.\121\ For both R16 and Euro NCAP, for vehicles 
that have occupant detection in the rear seats, the visual warning does 
not need to indicate unfastened seat belts for unoccupied seating 
positions.\122\
---------------------------------------------------------------------------

    \119\ Section 8.4.2.3.1.
    \120\ Section 3.4.1; Section 3.4.3.1.1.
    \121\ Section 3.4.1.
    \122\ Section 8.4.4.2 (R16; section 3.4.3.1.1 (Euro NCAP).
---------------------------------------------------------------------------

Comments
    Many ANPRM commenters either specifically recommended harmonizing 
with R16 or recommended triggers that harmonized with R16. Three 
commenters specifically recommended harmonizing with R16. Many other 
commenters recommended that the trigger be based on the ignition 
switch. One commenter explained that this would provide flexibility for 
novel approaches for classifying vehicle motion. A few commenters 
stated that it was necessary for the warning to activate before the 
vehicle was in motion; for example, it was noted that vehicle crashes 
can happen quickly (e.g., backing out of a parking spot), so vehicle 
occupants should be buckled up anytime the vehicle is in motion. A 
commenter also stated that delaying the warning until the vehicle is in 
drive mode could leave drivers unable to ensure all passenger belts are 
fastened. Delaying the warning might warrant additional study, but if 
the study suggests changing the warning timing, it should do so for all 
vehicle occupants. A commenter stated that any triggering condition 
other than initiation at the beginning of a trip when the ignition 
switch is moved to the ``on'' or ``start'' position would necessitate 
occupant detection.
    However, a few commenters suggested alternative approaches. One 
commenter recommended against requiring a warning before a driver 
shifts a vehicle into drive because a transmission-less electric 
vehicle can quickly shift to drive. Requiring the warning before the 
vehicle is shifted to drive would potentially amount to a seat belt 
drive interlock and potentially delay shifting into drive. The 
commenter believed this is unnecessary, could result in driver 
frustrations that diminish acceptance, and lead to hasty detection that 
increases the potential for error. Another commenter stated that the 
warning would be most effective if it were triggered when the seat is 
occupied, the belt is unfastened, and the vehicle's power is on. Yet 
another commenter stated that the triggering condition should be 
vehicle unlocking and for a period following relocking. Finally a 
commenter stated that the warning should be deactivated or disallowed 
if all occupants are properly buckled.
Agency Response
    NHTSA proposes that the warning begin when the vehicle's ignition 
switch is moved to the ``on'' or ``start'' position. This same 
condition appears in the existing driver seat belt warning requirements 
and is similar to ECE R16 and Euro NCAP. We are not proposing to follow 
R16 and refer to a ``master control switch'' because we do not believe 
it is necessary to introduce this new term into FMVSS No. 208 for the 
proposed amendments to the standard. Also similar to those protocols, 
if the system has occupant detection, no warning is required for 
unoccupied seats under the full-status and negative-only compliance 
options. As a commenter suggests, this would likely lead to more 
effective warnings because it mitigates false warnings and eases the 
burden on the driver to reconcile what the warning depicts with the 
actual status of the rear seat passengers. We believe basing the 
trigger on the ignition switch is preferable to delaying the warning 
until the vehicle is placed in gear because the proposed requirement 
would make it more likely that the occupants fasten their belts before 
the vehicle is in motion.\123\
---------------------------------------------------------------------------

    \123\ See DOT 2009 Seat Belt Study at 65.
---------------------------------------------------------------------------

    With respect to the commenter on transmission-less electric 
vehicles quickly shifting to drive, the warning is triggered by the 
ignition, not the transmission gear position and would not impede the 
driver from shifting to drive. NHTSA also disagrees with the commenter 
that the system would be triggered by the vehicle being unlocked. This 
could require a warning before any occupants had entered the vehicle, 
and thus would likely not serve its purpose of warning the driver and 
occupants given the limited duration of the warning. Such a requirement 
would also not harmonize with the existing driver belt warning system 
and the ECE R16 and Euro NCAP requirements.
    For the negative-only system, we propose to require a visual 
warning indicating which occupied seats have an unfastened seat belt 
for the required duration or until the belts at all occupied rear 
seating positions are in use. Therefore, like the R16 requirement, if 
all occupied seats have fastened seat belts no visual warning would be 
required.
c. Seat Occupancy Criteria and Interaction With Child Restraint Systems
    The negative-only and full-status compliance options would require 
the warning system to determine whether a seat position is occupied. 
Because the existing seat belt warning requirements in FMVSS No. 208, 
S7.3 apply only to the driver seat, they do not contemplate an occupant 
detection system (because driver seat occupancy could traditionally be 
assumed).
    There are three main detection scenarios an occupant detection 
system would be exposed to in the rear seats: adults, teenagers, and 
older children of various heights and weights; children seated in a 
child restraint system (CRS); and objects such as packages, pets, or 
unoccupied CRSs. This section will discuss how the occupant detection 
capability for negative-only and full-status systems should perform for 
these different scenarios and our proposed weight and height criteria 
for compliance testing of rear seat belt warning systems certified to 
either the negative-only or full-status compliance options.
    The ANPRM identified a need to objectively specify when a seat is 
occupied for the purposes of testing negative-only and full-status rear 
seat belt warning systems for compliance. The ANPRM requested comment 
on several options for seat occupancy criteria based on those specified 
in FMVSS No. 208 for compliance testing of low-risk deployment and 
suppression air bag systems in the presence of children or small-
stature adults. These fall into three main categories. First, FMVSS No. 
208 specifies 1-, 3-, and 6-year-old child anthropomorphic test devices 
(test dummies) (weighing, respectively, 22 lb [10 kg], 36 lb [16.3 kg], 
and 52 lb [23.6 kg]). Second, it

[[Page 61693]]

specifies a 5th percentile female test dummy (weighing 108 lb [50 kg]). 
Third, it specifies height and weight requirements for a child used as 
an alternative for the 6-year-old child test dummy for compliance 
testing of advanced air bag systems utilizing static suppression 
(weighing between 46.5 lb and 56.5 lb [21 kg and 25.6 kg] and between 
45 in and 49 in [114 cm and 124.5 cm] tall).\124\
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    \124\ FMVSS No. 208 S29.1(e).
---------------------------------------------------------------------------

    ECE R16 specifies three alternative methods for testing rear seats 
with occupant detection: placing a load of 40 kg (88 lb) on the seat; 
placing an object or human representing a 5th percentile adult female 
(the HIII-5F specified in 49 CFR part 572, as adjusted for the ECE 
test); or an alternative method specified by the vehicle 
manufacturer.\125\ Euro NCAP defines occupancy as the use by an 
occupant larger, taller, or heavier than a 5th percentile female.\126\
---------------------------------------------------------------------------

    \125\ Annex 18.
    \126\ Section 3.4.1.3.
---------------------------------------------------------------------------

    The ANPRM also sought comment on whether a rear seat belt warning 
would reliably detect a child restraint system attached by a child 
restraint anchorage system, or LATCH. The intent of this question was 
to determine whether a seat belt warning system might register a false 
alarm for a LATCH-installed CRS. Neither R16 nor Euro NCAP have 
requirements with respect to the system's interaction with LATCH-
installed CRSs.
Comments
    We received a number of comments related to seat occupancy criteria 
and the detection capabilities the system should have.
    With respect to seat occupancy criteria, several commenters 
supported harmonizing with ECE R16 and/or basing the criteria on a 5th 
female dummy (88 lb-105 lb). Several commenters suggested harmonizing 
with the ECE R16 criteria. A commenter stated that the occupant size 
that the system is required to detect should not be less than the 
occupant size that would use the seat belt as the only restraint. 
Another commenter stated that for children seated in booster seats or 
high-back boosters (with belt positioning guides), the CRS often 
directly utilizes the belt provided in the vehicle. In these cases, a 
rear belt reminder system may be useful for reminding the driver to 
ensure the child seated in that seating position is either restrained 
or providing an alert that the restraint status has changed during a 
trip (i.e., belt became unbuckled). A commenter recommended specifying 
the 5th percent female detection criteria for several reasons: starting 
with the 5th female would cover a large share of the target population; 
belt usage is high for children as long as they are in a CRS (so a 
warning system appears less needed); the 5th percent female includes a 
large share of the teenage population; it would harmonize with FMVSS 
No. 208 and international NCAP programs; and it would result in more 
robust systems with respect to false positives.
    On the other hand, various commenters recommended that the 
occupancy criteria be based on children that might reasonably be 
expected to use seat belts. Two commenters suggested that the occupancy 
criteria be based on the smallest weight of a child that can reasonably 
be expected to be restrained by a seat belt rather than a CRS. One of 
the commenters stated that a weight of 20 lb (9 kg) is consistent with 
all state laws for CRS use. Another commenter stated that the criteria 
should reflect a minimum weight equal to that of a Hybrid III 6-year 
old child (about 52 lb). However, as noted below, commenters believed 
that using weight alone was not enough. A commenter did not agree with 
criteria based on a 6-year-old, and instead suggested the HIII 3-year-
old dummy (36 pounds, or 16 kg) as the minimum weight threshold, 
stating that this dummy's weight roughly represents the 95th percentile 
2-year-old and the 5th percentile 5-year-old. The commenter stated a 6-
year-old was not appropriate as nearly 60% of 4- and 5-year-old 
children do not ride in a CRS with a harness, so many of the most 
vulnerable seat belt users (very young children using the belt alone or 
in conjunction with a booster) would fail to trigger the alarm if 
unbuckled. A commenter stated that the specifications should represent 
the occupant population at risk from non-use of rear seat belts, and 
stated that NHTSA's 2017 passenger vehicle fatality data indicates that 
restraint non-use exceeds the national average (47%) in the population 
of occupants starting at age 8-12; the unrestrained percentage for 
younger occupants is 36% for 4-7-year-olds and 22% for occupants less 
than 4 years old. A commenter suggested that the criteria should 
register children that would presumably be placed in a child restraint 
system (i.e., children as young as 4 years old). Another commenter 
recommended that NHTSA's testing reflect the full range of body types 
as well as child restraint systems that could be present in rear seats.
    We also received a variety of comments about the detection 
capabilities the system should have. Several commenters argued that the 
system should be required to detect CRSs. Three commenters supported 
requiring LATCH detection. Two of those commenters stated that the 
reminder system should be able to recognize when a car safety seat is 
installed with LATCH instead of the seat belt and should not activate 
under those conditions in order to avoid nuisance (false) warnings. A 
commenter said that when a CRS is installed using the lower anchors of 
the LATCH system, the seat belt is typically not in use, so a non-
discerning sensor would conclude that an unbuckled occupant is present 
(because a CRS is heavy enough to be classified as an occupant by an 
occupant detection system).\127\ A commenter recommended that the 
occupant detection system provide a warning if the CRS is improperly 
latched.
---------------------------------------------------------------------------

    \127\ Safe Ride News also appeared to suggest that in 
conjunction or in the alternative, the system should be able to be 
deactivated or allow the driver to dismiss (acknowledge) the 
warning. NHTSA's tentative conclusion to not adopt these approaches 
is explained in Section X.E, Resistance to intentional and 
inadvertent defeat and deactivation.
---------------------------------------------------------------------------

    On the other hand, several commenters believed that the system 
should not be required to detect a CRS. Three commenters stated that 
the system should not be required to detect a CRS, with two of the 
commenters noting variation in CRS designs and the fact that neither 
ECE R16 nor Euro NCAP require CRS detection capabilities. These three 
commenters opposed requiring LATCH detection because it would provide 
little benefit with significant added costs. One of the commenters 
added that LATCH systems are not typically latched/unlatched 
frequently, so it is far more uncommon to be in the unlatched state. 
Additionally, as only the latch could potentially be detected, and yet 
the remaining parts of the child restraint are unmonitored, it may give 
a false assurance to the user that the child is fully restrained. Two 
of the commenters said that if this were required, the system would 
need to distinguish different types of CRS available in the market, 
which would be difficult to implement. A commenter that opposed 
requiring occupant detection on buses, commented that buses with LATCH 
seats would require a detection system capable of differentiating 
whether an occupant is unbuckled or secured using the LATCH 
attachments; whether an occupant is unbuckled or secured using the 
securement harness provided with the seat; and between removed seats 
and those with incorrect electrical connections. Another commenter 
stated that CRSs pose a challenge to occupant

[[Page 61694]]

detection systems, which would need to account for all of the different 
uses of the rear seat; a false-positive warning on a child properly 
restrained using the LATCH system (who would not be buckled in with the 
seat belt) could discourage the consumer from using LATCH.
    Finally, some commenters advocated requiring more sophisticated 
detection capabilities in order to limit false positives. Two of these 
commenters suggested that the system should be able to discern the 
difference between an occupant and objects such as packages. Another 
commenter said that NHTSA should also limit false activations when 
seats are occupied by child seats or other items. A commenter stated 
that NHTSA should allow for a child seat mode that suppresses the 
warning.
Agency Response
    As an initial matter, it is important to understand the different 
types of CRSs, how seat belts are used with them, and the size/age of 
the children for which each type of CRS is typically appropriate.\128\
---------------------------------------------------------------------------

    \128\ All 50 states, the District of Columbia, and all United 
States territories have laws requiring children to be secured in the 
appropriate car seats or booster seats for their ages and sizes 
while riding in vehicles. Most states now require children to ride 
in appropriate car seats or booster seats until as old as age eight 
(Alaska covers children up to 15 years old as long as they fall 
within their specified height and weight criteria).
---------------------------------------------------------------------------

    There are essentially three types of CRSs: rear-facing CRSs, 
forward-facing CRSs, and booster seats.\129\ Rear-facing and forward-
facing CRSs are child seats that are installed using either LATCH \130\ 
or a seat belt to secure it in place.\131\ Booster seats raise and 
position a child so the vehicle's lap-and-shoulder belt fits properly.
---------------------------------------------------------------------------

    \129\ Within these types are CRS designs that can be used for 
multiple purposes, such as convertible CRSs that can be used as a 
rear-facing and forward-facing CRS and combination CRSs that can be 
used as a forward-facing CRS and booster seat.
    \130\ Many in the child passenger safety community refer to the 
child restraint anchorage system as the ``LATCH'' system, an 
abbreviation of the phrase ``Lower Anchors and Tethers for 
Children.'' The term was developed by a group of manufacturers and 
retailers for use in educating consumers on the availability and use 
of the anchorage system and for marketing purposes.
    \131\ Some boosters can also be secured to the seat with LATCH 
so that it stays in place when in use and not in use.
---------------------------------------------------------------------------

    NHTSA recommends that children remain in a rear-facing CRS until 
they reach the top height or weight limit allowed by the CRS 
manufacturer.\132\ NHTSA also recommends that children remain in a 
forward-facing car seat with a harness and tether until they reach the 
top height or weight limit allowed by the car seat's manufacturer. Most 
forward-facing CRS are rated for children up to 49 in (124 cm) and 65 
lb (29 kg).\133\ Once a child outgrows the forward-facing car seat with 
a harness, the child can travel in a booster seat and use a seat belt. 
NHTSA identifies an age range of 4-7 years old for when this transition 
to a booster typically occurs, depending on the height and weight of 
the child and the respective limits of their forward-facing car seat. 
Once a child outgrows the booster seat they can sit directly in the 
seat and use the seat belt alone; NHTSA identifies an age range of 
eight to thirteen and older for when this typically occurs.
---------------------------------------------------------------------------

    \132\ For the NHTSA recommendations discussed here, see https://www.nhtsa.gov/equipment/car-seats-and-booster-seats (last accessed 
Apr. 7, 2022).
    \133\ See https://www.healthychildren.org/English/safety-prevention/on-the-go/Pages/Car-Safety-Seats-Product-Listing.aspx.
---------------------------------------------------------------------------

    In the remainder of this section we discuss, first, the proposed 
weight and height criteria NHTSA proposes to use in compliance testing 
of rear seat belt warning systems certified to the negative-only or 
full-status compliance options and, second, what ability (if any) such 
systems should have to detect a CRS.
Weight and Height Criteria
    NHTSA believes the rear seat belt warning system should be able to 
detect an occupant that should be restrained with a seat belt alone and 
provide seat belt use information to the driver that is appropriate for 
that type of system. This target population is comprised of adults, 
teenagers, and children in booster seats. Children in booster seats are 
part of the target population because they should be restrained with 
the seat belt and so would benefit from a seat belt reminder. As 
mentioned above, the transition to a booster seat typically occurs from 
ages 4-7 years. Children in rear-facing and forward-facing CRSs are not 
part of the target population because these children are restrained by 
the CRS harness, not the seat belt. The intent of the reminder is not 
to warn of CRS misuse, but to warn of occupants not restrained by a 
belt alone.
    Accordingly, we are proposing that a rear designated seating 
position would be considered ``occupied'' when an occupant who weighs 
at least 46.5 lb (21 kg), and is at least 45 in (114 cm) tall, is 
seated there. These criteria are proxies for a six-year-old child, 
which roughly corresponds to a typical age at which a child would 
transition from a forward-facing CRS to a booster seat. We have taken 
these criteria from FMVSS No. 208, which uses them to specify the 
smallest child that may be used as an alternative to the 6-year-old 
dummy in static suppression tests under FMVSS No. 208. The proposed 
test does not specify the use of a booster seat because we are aware 
that children can be prematurely transitioned to a seat belt without 
the use of a booster,\134\ and we believe it is desirable to test the 
lower end of the possible weight range that encompasses children that 
could conceivably be restrained with a seat belt alone. As we explain 
below in Section XII.B, Test Procedures, the agency proposes using 
either a person or any anthropomorphic test device specified in part 
572 that meets these proposed weight and height criteria.\135\
---------------------------------------------------------------------------

    \134\ About 16.6 percent of children 4 to 7 years old were 
prematurely transitioned to seat belts in the ``2019 National Survey 
of the Use of Booster Seats'' (DOT HS 813 033).
    \135\ For anthropomorphic test devices, this would include the 
50th percentile male, 5th percentile female, and the 6-year-old and 
10-year-old child dummies.
---------------------------------------------------------------------------

    These criteria specify a smaller occupant than does R16. We 
tentatively believe that harmonizing with R16 and using a heavier dummy 
would not capture the child segment of the population that is in 
booster seats; that is, seat belt use may occur for occupants smaller 
than the criteria specified by R16. We also do not believe it is 
necessary to use a larger-size occupant because a system capable of 
recognizing a six-year-old should also be capable of recognizing larger 
occupants.
    At the same time, we tentatively believe that the proposed criteria 
are preferable to criteria reflecting a younger occupant (lower 
weight). The smallest dummy that would meet the proposed weight and 
height criteria is the 6-year-old dummy specified in part 572. The next 
smallest dummy represents a 3-year-old child (i.e., the Hybrid III 
three-year-old), but we believe it would not be appropriate to specify 
the use of the 3-year-old because a child represented by this ATD 
should be seated in a forward- or rear-facing CRS, not a booster seat.
Ability of the System To Detect a CRS
    NHTSA also does not propose to require any sort of CRS detection 
capabilities at this time.
    We tentatively believe that a forward- or rear-facing CRS installed 
with the seat belt would not cause problematic false warnings; rather 
it would just register the CRS as a buckled passenger.
    Similarly, we believe that a forward- or rear-facing CRS installed 
with LATCH would not pose issues necessitating any specific 
requirements related to the LATCH system, such as LATCH sensors. There 
are a few reasons for this. First, we do not believe

[[Page 61695]]

LATCH-installed CRSs would lead to false warnings or driver confusion 
about the belt status of any rear occupants, because NHTSA recommends 
buckling unused seat belts that are within reach of children to prevent 
seat belt entanglement and/or strangulation.\136\ This includes, for 
forward- or rear-facing CRSs installed with LATCH, buckling the unused 
belt behind the CRS. (Fastening the unused seat belt behind the CRS 
when installing a CRS with LATCH should not be mistaken for installing 
a CRS with both the seat belt and LATCH; a CRS installed with LATCH is 
not also installed with the seat belt unless it is approved by both the 
car seat and vehicle manufacturers.) If users follow NHTSA's 
recommendation and buckle the belt behind the CRS, the positive-only 
system would simply consider those belts to be fastened, and the 
negative- and full-status systems would not register a false warning. 
If the belt is not buckled as NHTSA recommends, with a positive-only 
system, the driver would simply see that there were no buckled belts, 
so there would be no false warnings. For the negative-only and full-
status systems (which utilize occupant detection), the system could 
register the child in the CRS as an occupant depending on the weight of 
the child and CRS. We are aware of at least one vehicle manufacturer 
that uses occupant detection for its rear seat belt warnings and it 
recommends fastening the unused seat belt if the CRS is installed with 
LATCH to avoid such a false warning. (In the owner's manual section of 
this preamble we seek comment on including such guidance in the owner's 
manual, which includes information provided by the vehicle manufacturer 
to the consumer, whether in digital or printed form.) Again, if the 
belt is not buckled as NHTSA recommends, the driver would need to take 
these facts into account when comparing the number of rear seat 
occupants against how many or which rear seat belts are reported to be 
in use by the warning system. Second, we are not proposing to require a 
warning for CRSs improperly attached to the LATCH because the focus of 
this rulemaking is on providing a seat belt warning, not on providing 
warnings for improperly installed LATCH child seats. Third, this 
approach is consistent with ECE R16 and Euro NCAP, neither of which 
have provisions for addressing LATCH-installed child restraints. 
Finally, requiring LATCH sensors would add extra complexity and cost.
---------------------------------------------------------------------------

    \136\ https://www.nhtsa.gov/road-safety/child-safety.
---------------------------------------------------------------------------

    We also do not believe a booster seat would present any special 
challenges to a seat belt warning system. If an (un)belted child is in 
a booster seat, the system would register the belt as not (un)fastened 
and (if equipped with occupant detection) that the seat was occupied. 
This would not necessitate the system to specifically detect the 
booster seat because the performance criteria are weight-based. In 
addition, we would not expect an occupant detection system to provide a 
false warning for an unoccupied booster seat because the proposed seat 
occupancy criteria (roughly equivalent to a 6-year-old) is heavier than 
an unoccupied booster seat.
    We are also not proposing to require more sophisticated features to 
test how well the system avoids false positives--e.g., the ability of 
the system to distinguish packages or pets from occupants or a child 
seat mode. A detection system that can differentiate between cargo and 
occupants would require additional sensor technology in comparison to a 
weight-based sensor and would be more costly. This issue can be 
mitigated by moving the cargo to the floor or trunk of the vehicle or 
by buckling the unused belt and would not be an issue for the positive-
only compliance option. Tesla's ``child seat mode'' allows the driver 
to acknowledge the warning triggered by a CRS installed with LATCH for 
that trip. With respect to Tesla's comment regarding a child seat mode, 
neither ECE R16 nor Euro NCAP contemplate this and we are not aware of 
other manufacturers that have employed this feature. Given that a child 
seat mode feature could be used to circumvent the warning (i.e., a belt 
use warning could be prevented or dismissed by use of the child seat 
mode), and the limited information NHTSA has on it, we have tentatively 
decided not to permit this feature.
    We seek comment on all these issues.
d. Minimum Duration
    The ANPRM also sought comment on the minimum duration of the 
warning. NHTSA's front seat belt warning research suggests that longer-
duration warnings are more effective, but also more annoying.\137\ The 
current driver's seat belt visual warning in FMVSS No. 208 is required 
to last at least 60 seconds under the second compliance option in FMVSS 
No. 208, S7.3(a)(2). Both R16 and Euro NCAP specify a 60-second visual 
warning (which may end sooner if the belt is fastened or the seat 
becomes unoccupied).
---------------------------------------------------------------------------

    \137\ DOT 2009 Belt Warning Study, supra n. 36.
---------------------------------------------------------------------------

Comments
    Many commenters recommended harmonizing with R16 and adopting 60 
seconds.\138\
---------------------------------------------------------------------------

    \138\ Global suggested not adopting the Euro NCAP duration 
requirement (90 seconds) because the warning must balance 
effectiveness and consumer acceptance, but NHTSA understands the 
Euro NCAP minimum duration to be 60 seconds.
---------------------------------------------------------------------------

    A few commenters advocated a longer warning. Two commenters 
recommended the warning should last until all occupants are buckled. 
One commenter said that systems with long single-cycle durations and 
those that cycle audible/visual reminders throughout the entirety of 
the drive are more effective than systems that cycle for a limited 
number of times.\139\
---------------------------------------------------------------------------

    \139\ NSC cited an IIHS study finding that an indefinite 
reminder and a 100 second constant reminder increased seat belt use 
by 30-34 percent over an intermittent reminder.
---------------------------------------------------------------------------

    Another commenter said that the visual warning duration should be 
based on evidence of effectiveness while maintaining a balance with 
annoyance.
Agency Response
    NHTSA is proposing that the warning last for at least 60 seconds. 
We believe that 60 seconds is sufficient to capture the driver's 
attention, and that a longer warning would have the potential to become 
distracting or a nuisance.\140\ This would be a shorter warning than we 
are proposing for the front outboard seats (see Section XI.C). There 
are a couple of reasons for our tentative decision that a shorter 
warning is warranted for the rear seats. First, we are not proposing to 
require occupant detection for the rear seat belt warning system; the 
positive-only compliance option would require that the driver be 
informed of which rear seat belts are fastened. This type of 
``warning'' functions more to provide information to the driver, rather 
than a true warning (because it will be providing information to the 
driver even if all rear occupants have fastened their seat belts), so 
we tentatively think that it is not necessary to require that this be 
particularly long-lasting. Second, and related, even for the compliance 
options that would entail occupant detection, the complexities of 
occupant detection in the rear seats and the possibilities for false 
positives provide another reason for not requiring an extremely long-
lasting warning. Manufacturers would be free to provide a longer 
warning if they wished. The proposed compliance

[[Page 61696]]

options requiring occupant detection would not require a warning for 
occupants with fastened belts.
---------------------------------------------------------------------------

    \140\ We are also proposing that these visual displays should 
not be overridden by other visual warnings for the required 
duration.
---------------------------------------------------------------------------

    This is consistent with ECE R16 and Euro NCAP and with systems 
currently deployed in the United States. Our preliminary analysis found 
that, of the 15 manufacturers that provide vehicle models with a rear 
seat belt warning system in the United States, 8 appear to provide 
systems with initial visual warnings that are active for at least 60 
seconds. An additional three manufacturers appear to provide visual 
warnings until the seat belt is fastened.
2. Audio-Visual Change-of-Status Warning
    The ANPRM sought comment on requiring a change-of-status warning 
for when a fastened seat belt is unfastened, including an audio-visual 
change-of-status warning. We also sought comment with respect to 
potential requirements for an audible warning, including the duration 
of the warning and whether NHTSA should specify additional warning 
characteristics (such as sound level).
    R16 specifies an audio-visual change-of-status warning for the rear 
seats. If a fastened rear belt becomes unfastened when the vehicle is 
in ``normal operation,'' \141\ R16 specifies an audio-visual warning 
(second level) when certain distance, time and/or speed threshold(s) 
(at the choice of the manufacturer) are exceeded.\142\ The additional 
thresholds are distance traveled (not to exceed 500 meters), vehicle 
speed (not to exceed 25 km/h, and/or travel time (not to exceed 60 
sec). This warning must last for at least 30 seconds unless the 
unfastened belt becomes fastened, the seat associated with the 
unfastened belt is no longer occupied, or the vehicle is no longer in 
normal operation.\143\ This warning may not be canceled by the driver.
---------------------------------------------------------------------------

    \141\ Defined as forward motion at a speed greater than 10 km/h. 
Sec.  2.47.
    \142\ Section 8.4.4.5.
    \143\ These summaries simplify the requirements somewhat. They 
will be discussed in greater detail later in the preamble where 
relevant.
---------------------------------------------------------------------------

    Euro NCAP also requires (in order to earn bonus points) an audio-
visual change-of-status warning at vehicle speeds of 25 km/h and 
above.\144\ If the change-of-status occurs below 25 km/h and no doors 
are opened, the signal may be delayed until the vehicle has been in 
forward motion for 500 meters or has reached a forward speed of 25 km/
h.\145\ A warning is not required if the system has occupant detection 
as long as all doors remain closed and the number of buckled positions 
remains the same, in order to minimize the number of false positives 
(e.g., children remaining in the vehicle but swapping seats in the rear 
while at a traffic light).\146\ The warning duration differs for the 
visual and audible warnings. With respect to the visual warning, if the 
system does not have occupant detection, the warning must last until 
the seat belt is fastened or 60 seconds have elapsed.\147\ If the 
system does have occupant detection, the signal must remain on until 
the belt is fastened. The audible warning must last until the belt is 
fastened,\148\ 30 seconds have elapsed,\149\ or the vehicle speed falls 
below 10 km/h.\150\
---------------------------------------------------------------------------

    \144\ Section 3.4.1.5.
    \145\ Section 3.4.1.5.
    \146\ Section 3.4.1.5.
    \147\ Section 3.4.3.1.1.
    \148\ Section 3.4.1.6.
    \149\ Section 3.4.3.2.
    \150\ Section 3.4.1.6. The audio signal must resume when the 
speed goes above 25 km/h and no doors have been opened and the seat 
belt(s) remain unbuckled. In addition, the audible signal may 
instead meet the requirements for the front seating positions, if 
the vehicle is equipped with occupant detection.
---------------------------------------------------------------------------

Comments
    Many commenters specifically supported requiring an audio-visual 
change-of-status warning. One commenter cited a survey of adult 
passengers who do not routinely use a seat belt in the rear in which 
62% of respondents said they would be more likely to use a seat belt if 
there was an audible warning compared with only 50% who said the same 
about a visual warning.
    With respect to the triggers for the warning, two commenters stated 
that a change-of-status warning should activate regardless of the 
speed.
    Several comments also discussed the duration of an audible alert. 
Several commenters recommended harmonizing with the 30 seconds required 
by R16. Other commenters argued for a longer audible warning, 
including: 60 seconds, 90 seconds, and until all occupants are buckled. 
One comment noted that audio-visual warnings that continue to cycle 
throughout the drive are more effective than limited-duration warnings. 
Another commenter recommended consistency with existing FMVSS No. 208 
audible warning systems for front occupants. Commenters stated that the 
duration should be based on evidence of effectiveness while maintaining 
a balance with annoyance. A commenter stated that, while information 
about the effect of an audio-visual rear seat belt warning on rear seat 
belt use is sparse, research on front seat belt warning systems 
suggests that an audio-visual warning lasting longer than 8 seconds 
would be expected to motivate an unbelted rear occupant to refasten the 
seat belt.
    With respect to other warning characteristics, three commenters 
recommended that the audible warning be heard throughout the vehicle. A 
commenter suggested following R16's requirement that the warning 
``consist of a continuous or an intermittent (pauses shall not exceed 1 
second) sound signal or of continuous vocal information.'' \151\ Two 
commenters said that specifying additional audible warning 
characteristics would be burdensome and unnecessary. A commenter said 
that there should be a balance of the sound level so that consumers 
would accept and react positively to the warning, and suggested it be 
the same as that for the driver. Another commenter recommended that the 
audible warning specification be based on evidence of effectiveness and 
suggested that maintaining consistency with other seat belt warning 
signals would be desirable. A commenter recommended consistency with 
existing FMVSS No. 208 audible warning systems for front occupants. And 
yet another commenter recommended a warning that is enhanced but does 
not rattle the driver.
---------------------------------------------------------------------------

    \151\ Section 8.4.2.2.1.
---------------------------------------------------------------------------

Agency Response
    The agency proposes to require an audio-visual warning when a rear 
seat belt is unbuckled during a trip. We propose that when the 
vehicle's ignition switch is in the ``on'' or ``start'' position, the 
vehicle's transmission selector is in a forward or reverse gear, and a 
rear seat belt in use changes to not being in use, the vehicle must 
activate a continuous or flashing visual warning consisting of icons 
\152\ or text visible to the driver, as well as a continuous or 
intermittent audible signal for a period of not less than 30 seconds, 
beginning when a seat belt in use changes to not being in use. The 
warnings could cut off sooner if the belt is refastened before the 
minimum time limit has been reached. Comments from vehicle 
manufacturers were largely in support of harmonizing with the ECE R16 
requirements, and the proposed requirements are comparable to the 
change-of-status warnings on vehicles currently equipped with rear seat 
belt warnings. For example, Volvo vehicles provide an audio-visual 
warning lasting until the belt is refastened.
---------------------------------------------------------------------------

    \152\ In the proposed regulatory text, we use the term 
``symbol'' instead of ``icon'' in order to be consistent with the 
current usage in FMVSS Nos. 101 and 208.
---------------------------------------------------------------------------

    We believe this warning will be an effective way to reduce the risk 
of injury

[[Page 61697]]

to rear seat occupants by alerting the driver when a passenger 
unbuckles during a trip. NHTSA's 2015 consumer survey found that a 
change-of-status warning is effective in getting passengers to refasten 
their seat belt.\153\ This may be an especially beneficial feature for 
drivers transporting children in the back seat. Such a warning may 
reduce the risk of injury to children by alerting the driver that a 
child has unbuckled his or her seat belt, providing the driver an 
opportunity to direct the child to re-buckle the belt. Fifty-five 
percent of the drivers surveyed by NHTSA who transport children in the 
rear seat and who said their children do not always use seat belts, 
have had the experience of their child unbuckling during a trip.\154\
---------------------------------------------------------------------------

    \153\ Paul Schroeder & Melanie Wilbur. 2015. Survey of Principal 
Drivers of Vehicles with a Rear Seat Belt Reminder System. 
Washington, DC: National Highway Traffic Safety Administration, 
[Found in the docket for this ANPRM.]
    \154\ Id. at 10. This percentage is based on a fairly small 
number (15) of drivers who reported that their children do not 
always use seat belts.
---------------------------------------------------------------------------

    The proposed requirements follow ECE R16 and Euro NCAP in that both 
of those protocols include an audio-visual rear belt change-of-status 
warning with specified trigger criteria.\155\ We tentatively agree with 
a commenter that a duration longer than 8 seconds is warranted because 
it will be more effective and believe that a 30-second minimum duration 
appropriately balances effectiveness and acceptance. We note that this 
is shorter than the duration we are proposing for the change-of-status 
warning for the front outboard seats (until the belt is re-fastened--
see Section XI.C.2) because we tentatively believe that a longer 
warning for the rear seats is more likely to lead to driver 
distraction, especially with children in the rear seats.
---------------------------------------------------------------------------

    \155\ Features of the change-of-status warning that are common 
with the start of trip warning--for example, the telltale 
characteristics--are discussed later in the preamble.
---------------------------------------------------------------------------

    The proposal differs from R16 and Euro NCAP in a few ways:
     Triggers. The warning would be required as long as the 
ignition is on and the transmission selector is in the drive or reverse 
position, with no additional thresholds or triggers, such as the 
vehicle having to reach a forward speed of 25 km/h. We tentatively 
believe this departure from R16 and Euro NCAP is justified. Seat belts 
provide a safety benefit even at lower speeds, and regardless of the 
direction of motion. We also believe a warning would be beneficial even 
if the vehicle is not moving. A driver may want to know if any rear 
seat occupants--especially children--have been unbuckled while the 
vehicle is temporarily stopped (e.g., at a traffic light) or slowed 
(e.g., in a parking lot), because the vehicle could soon be resuming 
travel. In addition, providing a warning when the vehicle is stationary 
would allow the driver to attend to the unbuckled passengers before 
having to focus attention on the driving task. We similarly believe 
that a warning would be useful before the vehicle has reached any 
distance or trip time threshold. We do not adopt the Euro NCAP 
allowance for not requiring a change-of-status warning when all doors 
remain closed and the number of buckled positions remains the same 
because this would require a delay in the activation of the change-of-
status warning; also, these types of events are likely limited and 
require very little time so exposure to the warning would be very 
limited. We do, however, adopt the Euro NCAP requirement that if a 
change-of-status occurs and a door is open, the system should consider 
that as the start of a new trip. This would allow for passengers to 
exit the vehicle when the driver does not shift into the park gear 
without activating the change-of-status warning for the full duration 
requirement.
     Duration. The proposed 30-second duration harmonizes with 
ECE R16 (though it is shorter than the 60-second duration for the 
visual signal specified in Euro NCAP, but consistent with the 30-second 
duration for the audible signal). We propose that the audible signal 
may be ``intermittent'' (i.e., not continuous), which mirrors the 
longstanding requirements for the driver's seat belt warning. ECE R16 
\156\ and Euro NCAP \157\ do not count periods in which the warning 
stops for longer than 3 seconds as part of the overall duration, and we 
have tentatively decided to propose a similar requirement for the rear 
audible change-of-status warning. (In contrast, we are specifying 
additional signal characteristics for the front seat belt change-of-
status warning because we are proposing to require a longer duration 
for that warning. This is discussed in Section XI.C.2)
---------------------------------------------------------------------------

    \156\ Section 8.4.2.4.1.
    \157\ Section 3.4.3.2.3.
---------------------------------------------------------------------------

     Audible warning characteristics. ECE R16 specifies that 
for intermittent audible warnings, the pauses shall not exceed 1 
second, and that gaps longer than 3 seconds would not count toward the 
required 30 second duration. Euro NCAP specifies that there must be no 
gaps greater than 10 seconds, and that gaps longer than 3 seconds would 
also not count toward their required duration. We have tentatively 
decided to propose a requirement that specifies that periods of time 
when the audible warning is not active for longer than 3 seconds would 
not count toward the required 30 second duration. Given the very 
limited duration of the rear seat change-of-status audible warning for 
the rear seats we believe this is a sufficient constraint for achieving 
an adequate warning. We have not further specified audible warning 
characteristics, such as volume or tone, in order to provide 
manufacturers design flexibility. The standard has required an audible 
driver's seat belt warning with no additional audible warning 
requirements since the early 1970s, so we believe manufacturers are 
familiar with designing and implementing optimal audible seat belt 
warnings. As mentioned above, we are specifying additional signal 
characteristics for the front seat belt change-of-status warning 
because we are proposing to require an indefinite duration for that 
warning, which requires more thought about the warning characteristics 
to mitigate the use of ineffective audible warnings (See Section 
XI.C.2).
    We seek comment on all aspects of the proposed change-of-status 
warning. Are there situations when the warning at a low speed would 
result in an unnecessary or unwanted warning, and how frequently would 
such situations occur? Are any of the deviations from R16 and/or Euro 
NCAP unwarranted, and what is the basis for such a conclusion? We 
acknowledge that the proposed requirements may still trigger the 
change-of-status warning for a short period of time until a door is 
opened when a passenger exits the vehicle and the vehicle is not in the 
park gear; however, we believe exposure to a very limited warning in 
these scenarios is necessary in order to capture other change-of-status 
events that occur when a vehicle is stopped but not in the park gear. 
We seek comment on how vehicle manufacturers are currently handling 
(e.g., what type of warning if any is provided) rear seat change-of-
status events that occur when the vehicle is stopped, but not in the 
park gear, or at low speeds (e.g., what type of warning, if any, is 
provided when passengers exit the vehicle without the vehicle being in 
the park gear)? As will be discussed later, we are proposing that the 
change-of-status warning for the front outboard seats be active until 
the seat belt that triggered the warning is refastened, so we seek 
comment on whether the proposed limited duration change-of-status 
warning for the rear seats should

[[Page 61698]]

also be required to last indefinitely until the rear seat belt is 
refastened.
3. Telltale Location
    A seat belt warning can function by alerting the driver that a rear 
seat belt is unbuckled, leaving it to the driver to request the rear 
passenger to buckle up. However, many other strategies are possible. 
For example, in addition to warning the driver, the front seat 
passenger could also be warned on the premise that, if the driver was 
occupied by other matters, the front seat passenger could direct the 
rear seat passengers to buckle up. Another strategy could be to warn 
the rear passenger(s) directly that their belt is unbuckled. Finally, 
in addition to warning the rear passenger(s), the driver and/or the 
front passenger could be warned. Some research suggests that having the 
warning visible to the unbelted occupant may increase 
effectiveness.\158\
---------------------------------------------------------------------------

    \158\ DOT 2007 Acceptability Study, supra n.78.
---------------------------------------------------------------------------

    ECE R16 requires that the visual warning be visible to the driver 
when they are facing forward,\159\ and Euro NCAP similarly requires 
that the visual signal be clearly visible to the driver without the 
need for the head to be moved from the normal driving position.\160\
---------------------------------------------------------------------------

    \159\ Section 8.4.2.1.1.
    \160\ Section 3.4.1.1.
---------------------------------------------------------------------------

Comments
    Most commenters recommended that the signal be visible to the 
driver, while one suggested the signal be visible to the rear seat 
passengers to avoid relying on the driver to enforce belt use, 
especially as rear-seat occupancy increases due to the increased use of 
for-hire vehicles (and, possibly at some time in the future, autonomous 
vehicles).
    Another commenter stated that it is impractical to provide a 
warning to rear passengers on buses due to wiring costs, customization, 
and FMVSS No. 222 requirements for head impact performance (for school 
buses).
Agency Response
    We agree with the majority of commenters and propose that the 
warning signal be visible to the driver. Although some research may 
suggest that having the warning visible to the unbelted occupant may 
increase effectiveness, we tentatively believe that the increased cost, 
complexity, and re-design such a requirement would entail would not be 
justified. However, manufacturers would have the flexibility to place 
the visual warning where it would be seen by some or all rear seat 
occupants. In Section XII.C we discuss the implications of the telltale 
location as it relates to automated vehicles.
4. Telltale Characteristics
    The ANPRM sought comment on whether we should propose requirements 
for telltale characteristics such as color and required text.
    For the current driver's seat belt warning, FMVSS No. 208 requires 
a continuous or flashing warning light displaying (at the choice of the 
manufacturer) either the telltale specified in FMVSS No. 101 (see 
Figure 2) or the words ``Fasten Seat Belts'' or ``Fasten Belts.'' \161\ 
The telltale must be visible to the driver \162\ in both daytime and 
nighttime.\163\ There are no color or illumination requirements for the 
telltale.\164\ The seat belt telltale may share a common space with 
other telltales except several specific telltales identified in FMVSS 
No. 101.\165\ Telltales in the same common space, however, may not be 
displayed simultaneously.\166\ The seat belt telltale must displace any 
other symbol or message in that common space while the underlying 
condition for the telltale's activation exists.\167\ Supplementary 
symbols or words may be used in conjunction with the required telltale 
or words.\168\
---------------------------------------------------------------------------

    \161\ FMVSS No. 208 S7.3(a) and FMVSS No. 101, table 2.
    \162\ FMVSS No. 208 S7.3; FMVSS No. 101 S5.1.2.
    \163\ FMVSS No. 101, S5.3.3(a).
    \164\ See Table 2.
    \165\ S5.5.2. These are: air bag malfunction, low tire pressure, 
electronic stability control malfunction, passenger air bag off, 
high beam, turn signal, and any brake system malfunction required by 
table 1 to be red.
    \166\ See FMVSS No. 101 S4 (``Common space'' is ``an area on 
which more than one telltale, indicator, identifier, or other 
message may be displayed, but not simultaneously'').
    \167\ FMVSS No. 101, S5.5.5.
    \168\ FMVSS No. 101, S5.2.3.
---------------------------------------------------------------------------

Figure 2--Seat Belt Telltale From FMVSS No. 101
[GRAPHIC] [TIFF OMITTED] TP07SE23.001

    The rear reminder requirements in ECE R16 mirror the FMVSS driver's 
warning requirements in several respects: the telltale may be flashing 
or steady; \169\ it must be recognizable in the daylight and at 
nighttime and distinguishable from other alerts; \170\ and there are no 
color requirements.\171\ However, R16 differs from the FMVSS 
requirements in that there is no required telltale symbol.\172\ R16 
also appears to require a visual warning that depicts all the rear 
seating positions.\173\
---------------------------------------------------------------------------

    \169\ Section 8.4.2.1.2.
    \170\ Section 8.4.2.1.1.
    \171\ Section 8.4.4.3.
    \172\ Section 8.4.4.3. A common telltale may be used for both 
the front and rear seat belt reminders. Section 8.4.4.4. The front 
reminder is required to utilize the symbol specified in Regulation 
121, which is the same symbol specified in FMVSS No. 101 and 
depicted in Figure 2.
    \173\ Section 8.4.4.2 (``The visual warning shall indicate at 
least al rear seating positions to allow the driver to identify, 
while facing forward as seated on the driver seat, any seating 
position in which the safety-belt is unfastened.'').
---------------------------------------------------------------------------

    Euro NCAP specifies that as soon as the audible part of the seat 
belt reminder signal starts, the visual signal needs to flash and be 
synchronized with the audible part.\174\
---------------------------------------------------------------------------

    \174\ Section 3.4.1.1.
---------------------------------------------------------------------------

Comments
    Several commenters favored standardized warnings. Two commenters 
stated that standardized telltales would help drivers recognize the 
icons when driving different/multiple vehicles (rentals, etc.).
    In contrast, other commenters urged NHTSA to provide manufacturers 
with

[[Page 61699]]

flexibility and not require a specific telltale. Two commenters 
specifically suggested harmonizing with ECE R16, in addition to the 
many commenters who generally urged harmonization with R16. A commenter 
requested flexibility to choose the indication method for each seating 
position, such as a telltale or a graphic or rendering of the vehicle 
seating positions in a more advanced display screen.\175\ Another 
commenter urged NHTSA to defer regulatory action on the establishment 
of a specific symbol and simply require that any telltale provided be 
communicated in the owner's manual because additional research is 
needed to determine which approaches may be most effective in 
communicating reminder status for a particular row or specific 
designated seating position, and emphasized its belief that NHTSA 
should not mandate specific indicators or display characteristics in 
order to provide OEMs with flexibility. Two commenters similarly 
suggested allowing the telltales for the rear seat belt reminder to 
differ (e.g., different colors, symbols) from those currently used for 
the front.
---------------------------------------------------------------------------

    \175\ Honda's comment seems ambiguous. It urges harmonization 
with R16, which does not require a specific telltale, but also 
states that the existing seat belt telltale in FMVSS No. 101 is a 
universally-recognized warning that can be used to provide a 
consistent link to additional seat belt information, and advocates 
using the FMVSS No. 101 telltale as a ``baseline warning'' to ensure 
that an active safety belt warning continues to be provided if an 
additional seat belt warning visual display needs to give priority 
to a more important safety warning.
---------------------------------------------------------------------------

    On the other hand, some commenters did not oppose requiring use of 
the current driver's seat belt telltale. A commenter said that a 
typical approach for rear seat belt warnings is to include a separate 
area on the instrument panel for separate telltale(s) for the rear 
seating position. These telltales could be specific to the actual 
seating position to inform the driver of the actual position that is 
buckled or unbuckled.
    A commenter said that the rear seat warning system should be 
coordinated with the driver warning, and that an ideal approach would 
be to provide a pictogram of the vehicle that has icons showing the 
seat belt status for each seating position. The commenter suggested 
this dashboard image could be combined with the door-ajar image, and it 
could even be enhanced to indicate whether a door's child safety lock 
feature is engaged. Similarly, a commenter stated that the warning 
should convey the location of each unbuckled occupant 
(negative[hyphen]only system for which occupant detection would be 
necessary).
Agency Response
    We are proposing that the visual warning be continuous or flashing 
and consist of icons or text and indicate how many or which rear seat 
belts are in use or not in use depending on the type of warning system. 
If icons are used to indicate how many or which rear belts are in use, 
we propose that icon(s) must be green; if icons are used to indicate to 
the driver how many or which belts are not in use, we propose that the 
icon(s) be red. If text is used to indicate to the driver how many or 
which rear seat belts are in use or not in use, we propose that the 
text contain the words ``rear belt(s) in use'' or ``rear belt(s) not in 
use.'' We also propose to amend table 2 in FMVSS No. 101, Controls and 
displays, to clarify that the ``Seat Belt Unfastened Telltale'' 
depicted there does not apply to the rear seat belt reminder. We also 
propose to amend able 1 in FMVSS No. 101 by adding in a row for the 
proposed rear seat belt warning. We agree with the merits of 
standardized warnings, but also seek to provide manufacturers 
flexibility to address their vehicle designs.
    The requirement that the visual warning be continuous or flashing 
mirrors the current driver's seat belt visual warning requirement and 
is also consistent with R16. However, we propose to depart from the 
current driver's warning and from R16 and standardize the color of the 
icons and text for the warnings to increase the likelihood that 
consumers would notice, recognize, and respond to the warnings. We 
believe that standardized colors and text will facilitate the 
interpretation of the signal. We are departing from the current 
driver's warning requirements and following R16 by not requiring 
specific icons because we believe the choice of icons would largely 
depend on whether the system displayed the number of seat belts in use 
or which seat belts are in use; this NPRM provides manufacturers 
flexibility in choosing which icons to use.
    Another difference between the proposal and R16 is that R16 
requires that the visual warning ``indicate at least all rear seating 
positions.'' We understand this to mean that the visual warning must 
depict all the rear seating positions. For instance, on some vehicles, 
Peugeot employs a visual warning that uses a schematic of the whole 
vehicle to indicate seat belt non-use or change-of-status for each 
seating position.\176\ Another manufacturer, Cupra, uses a visual 
warning, on some of its European vehicles, which depicts the status of 
all the seat belts in the rear seats without using a schematic of the 
whole vehicle.\177\
---------------------------------------------------------------------------

    \176\ https://public.servicebox.peugeot.com/APddb/modeles/3008/eGuide_ed02-16/pdfs/9999_9999_091_en-GB.pdf, pg. 144.
    \177\ https://www.cupraofficial.com/content/dam/public/cupra-website/owners/cupra-car-model-manuals/brochures/CUPRA_FORMENTOR_06_21_EN.pdf, pg. 17.
---------------------------------------------------------------------------

    In order to give manufacturers design flexibility, we do not 
propose to require that the warning depict all rear seating positions. 
Our proposed requirements would allow the visual warning to consist of 
text or icons indicating how many or which rear seats are fastened or 
unfastened. For example, the warning text might consist of ``Middle and 
Right rear seat belts fastened.'' Another visual warning option would 
be the seat belt icon with an adjacent numeral indicating the number of 
rear seat belts fastened. Accordingly, the proposal would allow, but 
not require, use of a pictogram as recommended by Safe Ride News. We 
are not requiring this because we believe it would be difficult to 
implement on vehicles such as passenger vans with many rear seats. (We 
also note that R16, which requires the visual warning to indicate all 
rear seats, does not apply to vehicles that transport more than eight 
passengers.) We acknowledge that vehicles with a larger number of rear 
seats, such as passenger vans/buses, may encounter visual signal 
complexities; however, we are not dictating specific types of signals 
in the proposed requirements in order to ensure manufacturers have 
adequate flexibility to address these types of issues. We think these 
vehicles, in particular, would benefit from the option to indicate how 
many rear seats are fastened.
    We seek comment on all of these issues, including the type of 
visual warnings that rear seat belt reminder systems employ currently 
or may employ in the future. We also seek comment on whether we should 
consider further aligning with R16 by requiring the visual warning to 
indicate all rear seating positions, which features of a visual warning 
would be appropriate for buses, and whether any further amendments to 
FMVSS No. 101 are necessary (e.g., the common space requirements in 
S5.5).
5. Belt Use Criteria
    The ANPRM sought comment on whether NHTSA should retain, for a rear 
seat belt warning, the criteria used for the current driver's seat belt 
warning to determine if the occupant is belted. The current driver's 
belt warning requirements specify that a belt is ``not in use'' when, 
at the option of the

[[Page 61700]]

manufacturer, either the seat belt latch mechanism is not fastened or 
the belt is not extended at least 10.16 centimeters (cm) (4 inches 
(in)) from its stowed position.\178\
---------------------------------------------------------------------------

    \178\ S7.3(c). These are the definitions for manual belts. For 
automatic belts, see infra Section XII.A.
---------------------------------------------------------------------------

    ECE R16 defines an ``unfastened'' belt to mean ``either the safety-
belt buckle of any occupant is not engaged or the length of the pulled 
out webbing is less than the length of the webbing which is needed to 
buckle an un-occupied seat in the rear most seating position.'' \179\ 
Euro NCAP does not specify a webbing spool-out criteria, and only 
refers to the status of the belt buckle.
---------------------------------------------------------------------------

    \179\ Section 2.46.
---------------------------------------------------------------------------

Comments
    Three commenters supported using the existing FMVSS No. 208 
criteria.
    A commenter suggested harmonizing with ECE R16, regardless of the 
type of system, in order to provide flexibility for vehicles that may 
have different characteristics with respect to rear row seating 
positions; for example, for rear seats that can be removed from a 
vehicle, providing an option whereby belt spooling can be used as an 
alternative to buckle latching may reduce challenges associated with 
any electrical connections that might be otherwise needed to provide 
functionality.
    Other commenters suggested using different belt use criteria 
considering the wide range of possible occupants, devices (e.g., car 
seats), and objects in rear seats, but did not offer possible 
solutions. One commenter stated that any seat belt use criteria should 
take into account whether a bypass system for CRS installation would be 
employed to prevent false warnings caused by using the lower anchors. 
Another commenter stated that the prolific use of LATCH seats and 
integrated child seats on buses will necessitate an alternate means of 
seat belt use detection.
Agency Response
    The current FMVSS No. 208 belt use criteria for the driver's seat 
belt warning requirements have been in place since 1974 and allow for 
the use of a belt latch or spool-out sensor. While these criteria would 
be effective for determining belt use for the initial seat belt 
warning, we believe the use of a spool-out sensor would not allow for 
an objective or reliable criterion for the proposed change-of-status 
warning. There may be instances where the webbing may not readily spool 
back in when the seat belt is unbuckled (e.g., due to the use of 
shoulder belt routing features or the use of a belt positioning booster 
seat), and thus would not reliably trigger the change-of-status 
warning. Therefore, we are proposing amending the belt use criteria in 
FMVSS No. 208, for the seat belt warning requirements, to rely on the 
use of a belt latch sensor, and not provide requirements that would 
accommodate the use of a spool-out sensor. We believe this is 
consistent with Euro NCAP. We invite comment on this tentative decision 
to not accommodate the use of spool-out sensors for the belt use 
criterion and request any data on the prevalence of the use of spool-
out sensors in the fleet.
    Concerns about false alarms triggered by LATCH use for the 
installation of child restraints are already addressed by the simple 
approach, in line with NHTSA's recommendations, that parents and 
caregivers fasten and lock the unused seat belts for the seat where the 
child restraint is being installed. This is an already existing agency 
recommendation to prevent seat belt entanglement and would prevent 
false warnings related to LATCH use.
6. Electrical Connections
    In the ANPRM, we explained that a rear seat belt warning system 
might require an electrical connection between the seat and the vehicle 
to relay the information gathered by a belt latch or webbing spool-out 
sensor to the rest of the warning system. A rear-belt warning system 
may therefore, as several commenters to the RFC noted,\180\ present 
potential wiring complexities, particularly in vehicles with removable, 
folding, rotating, or stowable seats. These types of seats might 
present an issue for a rear seat belt warning system because the 
electrical connection might not be automatically reestablished for 
these seats when the seat is reinstalled. There could be instances with 
manual connection seats where the driver either forgets to make the 
connection or makes an improper connection. Even for seats where the 
connections are automatically established when the seat is reinstalled, 
the automatic connectors might malfunction. If the electrical 
connection is not reestablished, the warning system could malfunction 
or provide inaccurate information. Removable seats are mainly found in 
the second row of minivans.\181\ Foldable, rotating or otherwise 
stowable seats (e.g., Stow-n-Go, Flip and Fold) are prominent in the 
third row of minivans or large SUVs. Foldable or stowable seats in the 
second row are not as prominent in minivans.
---------------------------------------------------------------------------

    \180\ See Docket No. NHTSA-2010-0061 (comments of IEE S.A., 
Alliance of Automobile Manufacturers, Association of Global 
Automakers, and Automotive Safety Council).
    \181\ We consider readily removable seats to be seats designed 
to be easily removed and replaced by means installed by the 
manufacturer for that purpose (see FMVSS No. 208 S4.1.4.2.2.), and 
do not require any special tools for their removal.
---------------------------------------------------------------------------

    Neither Euro NCAP nor ECE R16 have any requirements that address 
the potential for improper electrical connections for such seats. The 
ECE regulations provide that the rear seat belt warning requirements 
would not apply to folding rear seats or to seats fitted with an s-type 
belt (including a harness belt) until September 2022.\182\ Euro NCAP 
does not exclude folding seats and includes all seating positions 
including optional and removable seats, but does not require the 
monitoring of the buckle status for rear seat belt secondary buckles 
that require a tool to unlock.
---------------------------------------------------------------------------

    \182\ See Sections 8.4.1.3 and 15.4.2.
---------------------------------------------------------------------------

Comments
    Three commenter stated that removable, suspension and folding seats 
are complex and raise reliability and technological readiness concerns 
and should be exempted from the warning requirements until it would be 
practicable. Two of these commenters said that if a seat belt warning 
were required for such seats, significant lead time or a phase-in 
(e.g., until the vehicle platform was updated) would be necessary.
    Commenters stated that a rule should include some or all of these 
seat types. A commenter stated that, although these seats may present 
challenges for rear seat belt warning systems, NHTSA has provided no 
evidence that, in cases other than removable seats, the challenges 
would be insurmountable, or quantified the portion of the target 
population represented by occupants of these types of seats, which 
likely includes many children. Another commenter stated that removable 
seats would not need to be exempted from the requirements (as they 
currently are from ECE R16) if specific types of electrical connections 
or technology (e.g., wired buckle switch, wireless buckle switch, belt 
extension) were not required.
    Commenters said that electrical connections for removable, 
rotating, flipping and folding seats should not require any action on 
the part of the consumer because vehicles with these seats frequently 
transport children, and believed that NHTSA should also consider 
requiring wireless connections and a warning for an improper 
connection.
    Commenters were against any prescriptive design requirements 
related to the connection between the vehicle

[[Page 61701]]

and any removeable, folding, rotating, or stowable seats, and in favor 
of a robust set of compliance options to facilitate new technology 
(although one commenter also said that any additional time it would 
take NHTSA to develop such options would not be justified by the 
limited benefits and relatively small number of affected vehicles). A 
commenter said that NHTSA should instead include a reliability 
requirement (e.g., lifetime warranty).
    Two commenters expressed concerns with wiring complexities 
associated with buses. One of these commenters specifically noted 
track-mounted seats, which can be repositioned by the end user, which 
are also subject to improper connections and for which wireless 
communication technology is not currently available.
Agency Response
    We have tentatively decided not to exempt any of these seat types 
from the proposed requirements. We are not exempting suspension and/or 
folding seats; the electrical connections should not be disturbed 
because these seats are not readily removable, and they would 
potentially just require additional wiring to accommodate the folding 
or stowing process. We are also not exempting removable seats because 
we tentatively believe that concerns with improper electrical 
connections will be addressed by the proposed warning requirement 
discussed below. Applying the requirements to these seats also 
harmonizes with ECE R16 (which will soon fully phase in the rear belt 
requirements for these seats) and Euro NCAP. We do not consider a 
phase-in necessary for suspension and/or folding seats because we 
believe the solution for these seats is simple. For removable seats a 
phase-in is unnecessary because readily attachable electrical 
connections appear feasible. We do not believe buses would be subject 
to these requirements, given our definition of readily removable seats.
    We have tentatively decided not to propose any requirements with 
respect to the electrical connections for folding, rotating, or 
stowable seats. Because these seats are not readily removable, the 
electrical connections should not be disturbed and could be 
accommodated with additional wiring. We are, however, proposing two 
requirements related to the electrical connections for readily 
removable seats.
    First, we are proposing that readily removable seats must either 
automatically connect the electrical connections when the seat is put 
in place (i.e., not require the vehicle user to take any additional 
action to reconnect the electrical connections other than re-installing 
the seat) or, if a manual connection is required (i.e., the user must 
reconnect the electrical system), the connectors must be readily-
accessible.\183\ By readily-accessible connectors we mean connectors 
that are easy for an ordinary consumer to see and access. A system 
utilizing a wireless connection could be classified as either automatic 
or manual, depending on whether the user needs to take any additional 
actions to establish the wireless connection. We agree with the 
commenters who recommended no prescriptive requirements in order to 
ensure OEMs have flexibility in system design. We think the proposal 
balances flexibility and the need to ensure that a proper connection is 
made.
---------------------------------------------------------------------------

    \183\ As we note in Section X.C.7 below, we also propose that 
the owner's manual (which includes information provided by the 
vehicle manufacturer to the consumer, whether in digital or printed 
form) include instructions on how to make any manual electric 
connections for readily removable seats.
---------------------------------------------------------------------------

    Second, we are proposing that vehicles utilizing the negative-only 
compliance option provide a visual warning to the driver if a proper 
electrical connection has not been established for a readily removable 
seat. We are concerned that consumers could reinstall removable seats 
(with either automatic or manual connections) without making a proper 
electrical connection. There could be instances for manual connection 
seats where the driver either forgets to make the connection or makes 
an improper connection. Even for seats where the connections are 
automatically established when the seat is reinstalled, the automatic 
connectors might malfunction (e.g., debris, broken connector) and a 
proper connection may not be made. If the electrical connection is not 
reestablished, the warning system could malfunction or provide 
inaccurate information. We are only proposing to require the warning 
for negative-only systems because a faulty connection would result in 
the system not triggering any warning of an unbelted rear seat 
occupant. Moreover, the driver would otherwise have no reason to 
suspect that the system was malfunctioning, and so might mistake the 
lack of a warning as an indication that the rear seat occupant was 
belted.
    These potentially serious problems are not present in full-status 
or positive-only warning systems. First, it is our expectation that a 
faulty connection for a full-status system would affect both the 
occupant detection and belt status. However, if for some reason this is 
not the case and the occupant detection of a full-status system is 
working properly, but the seat belt buckle sensor is not connected 
properly, then no visual warning should activate without input from the 
buckle sensor and the driver should easily recognize the system is not 
working properly. If for this same scenario, the system interprets a 
lack of input from the seat belt sensor as an unbuckled seat belt when 
the driver verifies or requests the rear seat occupant to buckle their 
seat belt and the occupant is already buckled, then the driver would 
again be aware the system is not working properly. If the occupant 
detection sensors are not connected properly, the driver would be aware 
of the number of rear seat occupants being transported, and would thus 
be aware that the system is not operating correctly when there is not a 
warning for each occupant. Similarly, if there were not a good 
connection in a vehicle with a positive-only system, an unbelted rear 
seat occupant would not register as belted, which would be accurate; a 
belted passenger would also not register as belted, but since the 
passenger would be belted, there would be no adverse consequences from 
the system error if a crash were to occur.
    We believe that both of these requirements would mainly affect 
minivans, which make up a small percentage of the fleet.\184\ We 
believe it might be possible to utilize the rear seat belt visual 
warning signal, with slight modifications (e.g., a different color). 
The agency seeks comments on this proposal, particularly on the safety 
need for such warnings, costs, and feasibility of the proposed warning. 
We also seek comment on whether this telltale should be added to table 
2 of FMVSS No. 101, Controls and displays.
---------------------------------------------------------------------------

    \184\ We estimate that minivans make up 3.6% of vehicles 
produced based on MY 2015 WardsAuto production data. The number of 
minivans that would potentially be affected by this proposed 
requirement is less than 3.6%, because some minivans only have 
foldable/stowable rear seats, not removable seats.
---------------------------------------------------------------------------

    None of the regulations or statutes administered by NHTSA require 
manufacturers to provide a lifetime warranty. However, if a vehicle or 
item of equipment is determined (by the manufacturer or NHTSA) to have 
a safety-related defect or fails to meet an applicable FMVSS, the 
Safety Act requires the manufacturer to notify the owner of the defect 
or noncompliance and (if the vehicle or item is not more than 15 years 
old) remedy the vehicle or item without charge to the vehicle owner.
7. Owner's Manual Instructions
    The ANPRM sought comment on requiring the owner's manual to provide

[[Page 61702]]

information on the warning system's features, including the location, 
format, and meaning of the visual warnings. Because the owner's manual 
readership may be relatively low,\185\ we also sought comment on 
whether this information should be displayed in the vehicle instead of 
(or in addition to) the owner's manual.
---------------------------------------------------------------------------

    \185\ The National Child Restraint Use Special Study found that 
only 13 percent of drivers reported reading the vehicle owner's 
manual. Nathan K. Greenwell. 2015. DOT HS 812 142. Washington, DC: 
U.S. Department of Transportation, National Highway Traffic Safety 
Administration, p. 10.
---------------------------------------------------------------------------

Comments
    None of the commenters opposed such a requirement. Several 
commenters supported including such information in the owner's manual. 
Some commenters requested flexibility in describing the functionality 
of the system. One commenter suggested that the owner's manual could 
include information on the seating positions where a rear-seat reminder 
is provided, a description of the visual and audible warning(s), an 
indication of whether the system incorporates driver monitoring 
(including any limitations), instructions for deactivating or 
cancelling any warning(s), any limitations related to CRS, and 
information related to the connection of removable, folding, rotating, 
or stowable seats.
    A commenter believed that information should also be displayed in-
vehicle, especially for one-time vehicle users (renters, friends, 
family), and especially with respect to electrical connections for 
removable/stowable seats. Another commenter believed that more research 
on the best way to communicate this to owners is needed.
    A commenter stated that information on how a rear seat belt 
reminder affects CRS installation should be provided, including whether 
the system is able to detect a CRS (and avoid false warnings).
Agency Response
    We propose that the owner's manual (which includes information 
provided by the vehicle manufacturer to the consumer, whether in 
digital or printed form) describe the warning system's features, 
including the location, format, and meaning of the visual warnings. We 
also propose that the owner's manual include instructions on how to 
make any manual electrical connections for readily removable seats. 
This will provide manufacturers flexibility for how they describe the 
functionality of the system. These proposed additions to the owner's 
manual requirements in FMVSS No. 208 would require a revision to the 
approved collection of information OMB No. 2127-0541. Later in this 
proposed rule, we seek comment on this revision.
    With regard to including system functionality information in the 
vehicle itself, these types of vehicle features are not normally 
explained visually in the vehicle, other than information on air bags 
which pose safety risks. This level of detail is best described in the 
owner's manual.
    We are aware of at least one manufacturer that provides information 
in the owner's manual on how their rear belt warning system with 
occupant detection functions when a CRS is installed with LATCH and 
guidance on how to avoid activating the warning (for example, it 
informs the consumer that fastening the seat belt prior to installing a 
CRS with LATCH will avoid activating the warning system for that 
seat).\186\ We seek comment on whether we should require including such 
information in the owner's manual (which includes information provided 
by the vehicle manufacturer to the consumer, whether in digital or 
printed form).
---------------------------------------------------------------------------

    \186\ As noted earlier, NHTSA recommends buckling unused seat 
belts that are within reach of children to prevent seat belt 
entanglement and/or strangulation.
---------------------------------------------------------------------------

8. Interaction With Other Vehicle Warnings
    The ANPRM also solicited comment on whether a rear seat belt 
warning could conflict with other in-vehicle warnings, and how this 
might be addressed.
Comments
    A few commenters believed that the rear belt reminder could 
conflict with other warnings. One commenter believed that there are 
conflicts and that the rear seat belt warnings should be given priority 
over other warnings. Two commenters recommended that NHTSA provide 
flexibility for rear-seat reminder system alerts (or aspects of the 
alert) to be temporarily suppressed or paused where it is necessary to 
alert or redirect the driver's attention to higher-priority warnings--
for example, related to the operation of the vehicle or a potential 
safety risk within the external roadway environment, such as an alert 
provided by an advanced driver assistance system (ADAS), crash 
avoidance system or automated driving system (ADS) request to 
intervene. Another commenter recommended that the existing FMVSS No. 
101 Seat Belt Unfastened Telltale be utilized as a persistent 
``baseline'' warning when there is an active seat belt warning for any 
occupant, even in the event that the display of detailed seat belt 
information is prevented by a higher priority warning.
    Other commenters did not believe there would be conflicts with 
other warnings, and one manufacturer did not believe there would be a 
conflict if the audible warning is accompanied by a visual warning.
Agency Response
    NHTSA is proposing that the rear seat belt reminder telltale must 
not be overridden by other visual warnings for the required duration. 
This is consistent with the current requirements in FMVSS No. 101 for 
the driver's seat belt warning which specify, among other things, that 
the seat belt telltale must displace any other symbol or message in 
that common space while the underlying condition for the telltale's 
activation exists.\187\ We do not believe that the seat belt warning 
requirements will interfere with other warnings for safety systems 
since they have dedicated warning signals. This should give 
manufacturers the flexibility to determine the best way to implement 
their warnings. For instance, warnings for a potential safety risk can 
be more aggressive than those for the seat belts. With regard to 
available space, the visual signal might be displayed as a telltale 
light on the instrument panel or on the vehicle's information display 
screen. Manufacturers will also have to determine whether the driver 
and rear passenger seat belt visual warning will be treated the same.
---------------------------------------------------------------------------

    \187\ FMVSS No. 101, S5.5.5. See discussion supra, Section 
X.C.4, Telltale characteristics.
---------------------------------------------------------------------------

D. Alternative Warning Signals

    The ANPRM sought comment on requiring or specifying as a compliance 
option a rear seat belt warning that differs from the type of audio-
visual warning that is currently required for the driver's seat belt. 
Alternatives to a visual warning on vehicle start-up could include an 
audible signal, either electronic or mechanical, or a haptic warning 
(e.g., steering wheel or seat vibration). Similarly, an audible or 
visual warning of a change in the status of rear seat belts could be 
either electronic or mechanical and could include a haptic signal. We 
also sought comment on alternative solutions that would alert the 
driver when a rear seat passenger buckles and/or unbuckles (e.g., 
mirrors to see whether belts are buckled, or the sound of the latch 
plate clicking into the buckle).
Comments
    Many commenters recommended requiring the traditional audio-visual

[[Page 61703]]

warnings currently used for the front seats. One commenter stated that 
warning specifications should be based on effectiveness and that audio-
visual warnings would likely be highly effective given occupants' 
familiarity with them; it did not believe that a less-sophisticated 
warning, such as a specialized system of mirrors, would be sufficient 
to inform the driver about the status of the rear seat belts. Two 
commenters noted the potential for confusion/distraction if an 
alternative warning were used. A commenter stated that the ``click'' of 
the belt buckle, while certainly evidence of a buckled seat belt, can 
easily be missed by the driver and other occupants, as it could be 
masked not only by the drivers' own belt clicking, but also by ambient 
noise in the vehicle, and that, given the research supporting the 
effectiveness of an audio-visual signal, an alternative warning system 
would not be acceptable. Two commenters said that an alternate warning 
is not necessary because ECE R16's requirements are adequate.
    A commenter said that, in addition to requiring an audio-visual 
warning, the proposed rule should require a notification on the 
instrument cluster if a seat belt is unbuckled that must be 
acknowledged by the driver before any other use of the instrument panel 
is permitted.
    A commenter stated that rear seat belt warnings are not practicable 
for buses, but if they were used, an audible alarm similar to that 
required for emergency exits would be necessary to provide an effective 
notice to the driver. The commenter believed that the interior mirror 
on buses designed to permit the driver to view the passengers, while 
not as effective in determining proper seat belt use as an electronic 
monitoring system, has been effective in aiding the driver to observe 
passengers that were obviously not properly belted. The commenter did 
not support the use of haptic signals on buses. A public commenter 
suggested use of cameras.
Agency Response
    We agree with the commenters who believe that an alternative 
warning is not necessary and that an audio-visual warning would be 
appropriate.\188\ Cameras would be unnecessary and would add cost. The 
agency believes that mirrors alone would not be as effective as an 
audio-visual warning and may pose risks, as drivers would have to study 
the view to determine belt status, assuming they could clearly see the 
belts. In addition, as explained above, the proposed rule would not 
apply to school buses.
---------------------------------------------------------------------------

    \188\ With respect to Blue Bird's argument regarding the 
practicability of a rear warning for buses, see Section X.B, 
Applicability.
---------------------------------------------------------------------------

    We are specifying minimum performance requirements in order to 
balance the effectiveness and acceptability of these systems. 
Manufacturers can go beyond our requirements, such as by providing a 
warning on the instrument panel that must be acknowledged by the driver 
before any other use of the instrument panel is permitted.

E. Resistance to Intentional and Inadvertent Defeat and Deactivation

    The ANPRM sought comment on whether NHTSA should propose 
requirements to address circumvention. We pointed to agency research on 
the development of a seat belt misuse detection system that identified 
a number of ways in which a rear seat belt warning system might be 
intentionally defeated, as well as potential countermeasures.\189\ For 
example, a warning system could be defeated if:
---------------------------------------------------------------------------

    \189\ Mazzae, E.N., Baldwin, G.H.S., & Andrella, A.T. (2018, 
October). Performance assessment of prototype seat belt misuse 
detection system (Report No. DOT HS 812 593). Washington, DC: 
National Highway Traffic Safety Administration.
---------------------------------------------------------------------------

     The belt is buckled before the occupant sits in the seat. 
This could be addressed by requiring a sequential logic system. A 
sequential logic system would require that the belt be buckled after 
the seat has been occupied in order for the system to recognize the 
seat belt as being buckled.
     An occupant buckles the seat belt behind themselves. This 
could be addressed by utilizing both seat belt latch and spool-out 
sensors and deactivating the warning only if the webbing were spooled 
out more than a predetermined length. However, even these sensors could 
be defeated by pulling out additional webbing and clipping it off to 
prevent retraction.
     The seat belt and/or occupant detection sensors utilized 
by the rear warning system in vehicles with removable rear seats are 
intentionally disconnected.
    We also noted some ways in which the warning could be inadvertently 
circumvented (for example, when the driver uses a remote engine starter 
so that the initial warning activates before the driver is in the 
vehicle).
    We also sought comment on whether a feature allowing single-trip 
manual deactivation would diminish the likelihood of circumvention. The 
ECE regulations allow the rear seat belt warning system to incorporate 
a short-term and/or a long-term deactivation feature for the audible 
change-of-status warning.\190\ Under those regulations, a short-term 
deactivation may only be effectuated by specific controls that are not 
integrated in the safety-belt buckle, and only when the vehicle is 
stationary.\191\ When the ignition or master control switch is 
deactivated for more than 30 minutes and activated again, a short-term 
deactivated safety-belt reminder must reactivate. A long-term 
deactivation may only be effectuated by a sequence of operations that 
are detailed only in the manufacturer's technical manual or which 
require tools that are not provided with the vehicle. It must not be 
possible to provide either short- or long-term deactivation of the 
visual warning. Under Euro NCAP, the system may allow the driver to 
acknowledge the signal and switch it off for that unique event, except 
for change-of-status events; a new trigger of the warning should not be 
prevented.\192\ We therefore understand there to be two distinct but 
related concepts in the ECE regulations and Euro NCAP: acknowledgement 
and deactivation. The former allows the driver to turn off the signal 
once it is activated, while the latter prevents the signal from 
activating altogether. In addition, FMVSS No. 101 provides that 
telltales for several functions (such as high beams), but not including 
the driver's seat belt warning, must not be cancelable while the 
underlying condition for their activation exists.\193\
---------------------------------------------------------------------------

    \190\ Section 8.4.5.
    \191\ Section 8.4.5.1.
    \192\ Section 3.4.3.1.2.
    \193\ S5.5.6(b).
---------------------------------------------------------------------------

Comments
    Several commenters supported addressing intentional and/or 
inadvertent defeat. A commenter stated that, given the relatively small 
proportion of hard-core nonusers, the proportion of the potential 
target population seeking to intentionally defeat the systems is 
relatively small. Nonetheless, the commenter stated that, if mitigation 
strategies can be built into the systems, such an advance would likely 
help address at least some portion of ``hard-core nonusers'' as well as 
those exhibiting inadvertent misuse. Commenters believed that the cost 
of the potential countermeasures would be minimal, and they should be 
required to the extent feasible. A commenter stated that the rear 
warning system should include appropriate requirements for inadvertent 
defeat, but not intentional defeat. Another commenter supported 
investigating the possibility of eliminating the ``false comply''

[[Page 61704]]

condition of buckling behind the back or extracting and ``pinning'' the 
belt without buckling. One potential option is to replicate current 
systems used to identify seat belt use for front seated occupants, as 
occupant detection systems can also assist with identifying misuse. 
They also commented that sensor technology that identifies belt 
pullout, occupant location, and buckle switches can add redundancy and 
reduce the risk of intentional and inadvertent defeat.
    Other commenters disagreed with hardening the system against 
circumvention because it would be burdensome and unnecessary (minimal 
benefits). One commenter noted the relatively small proportion of 
drivers who circumvent the seat belt warning.
    With respect to deactivation, three commenters supported following 
R16, and IEE supported following R16 and/or Euro NCAP. Three other 
commenters opposed allowing deactivation because it would drastically 
weaken system effectiveness.
    We also received comments on the interaction with a remote engine 
starter and the warning. A commenter believed that adopting the 
requirements of R16 should help address this issue, as warnings must be 
provided when the ignition switch (or master control switch) is 
activated (i.e., capable of being driven). The commenter also believed 
that the current driver's warning requirements (where the warning is 
provided beginning when the vehicle ignition switch is moved to the 
``on'' or the ``start'' position) address this issue. Another commenter 
recommended that NHTSA specify the start of the drive as the moment 
when the ignition is activated in the mode where the vehicle is capable 
of being driven. A commenter stated that this potential issue can 
easily be avoided with occupant detection, because the warning cycle 
would only be triggered based on the actual presence of occupants.
Agency Response
    We have tentatively decided not to propose any system-hardening 
features. In drafting this proposal, the agency focused on extending 
the rear seat belt warning technologies currently in a relatively small 
proportion of vehicles to the rest of the fleet. These existing systems 
generally do not provide mechanisms to limit circumvention. We decided 
not to include requirements to address circumvention for a variety of 
reasons. Most importantly, doing so would increase cost and complexity. 
For example, since we are not proposing to require occupant detection 
technology, we are not proposing a sequential logic system. We also 
believe that because the proposed warnings are minimally intrusive--a 
relatively short-duration visual warning on start-up, and an additional 
short audio-visual warning for a seat belt that is subsequently 
unbuckled--attempts to defeat the system will be rare.
    We have also tentatively decided not to allow acknowledgement or 
deactivation of the required warning signals. While some commenters 
suggested adopting the R16 requirements, they did not offer further 
information on the need or use of these options, except for one 
commenter that noted it would diminish the safety value of the system. 
Therefore, we believe that proposing to allow an acknowledgment, short-
term deactivation, and or long-term deactivation option would have a 
net negative impact on the effectiveness of the proposed warning system 
(the driver would not get the full benefit of the warning). As 
discussed earlier in this proposed rule, we believe that the proposed 
warnings are minimally intrusive and have relatively short durations 
(visual-only at start-up and audio-visual for a change-of-status), and 
the positive-only compliance option would mitigate warnings for 
unoccupied seats. In addition, we believe that allowing the driver to 
turn off the change-of-status warning would not meet the need for 
safety. Since we cannot justify allowing such options from a safety 
perspective (allowing it would negatively impact the effectiveness of 
the systems) or consumer acceptance perspective (warning signals are 
unobtrusive and vehicle manufacturers could opt for the positive-only 
option), we have tentatively decided not to allow either a deactivation 
or acknowledgment option. For this reason, we also propose amending 
FMVSS No. 101 S5.5.6(b) by adding the seat belt telltale to the list of 
telltales that may not be cancellable while the underlying condition 
for the telltale exists. This would apply to both the front and rear 
seat belt warnings. This would mean that the seat belt warning telltale 
would not be allowed to be acknowledged (i.e., cancelled) until the 
minimum warning duration had been reached.
    We seek comment on vehicle manufacturers' desire to provide such 
options, and, if they currently offer such options, how they have 
implemented them. We also seek comment on whether allowing such options 
would affect manufacturers' choice of compliance option (e.g., if we 
allowed acknowledging or deactivating the warning signals, would they 
be more inclined to choose the negative-only or full-status compliance 
options?). We also seek comment on our proposed revision of FMVSS No. 
101.
    In vehicles with a remote engine starter, the driver would 
potentially not be present to witness the initial warning signals if 
they are designed to meet our minimum requirements. This could 
potentially be addressed by programming the system to require input 
from the door sensors or occupant sensors to verify that the driver is 
in the vehicle, or by requiring the signals to initiate when the 
transmission is moved out of the park mode. We have chosen not to 
propose a strategy for this scenario, but request comments on 
practicable solutions to this problem that could be implemented in the 
final rule and the potential cost impacts. New technologies or 
solutions may be available that may address these scenarios without 
limiting the design flexibility of manufacturers or significantly 
increasing the cost.

F. Consumer Acceptance

    In the ANPRM we explained that in order for the proposed rear seat 
belt warning to have a lasting impact on seat belt use, it must balance 
effectiveness and acceptability. For a seat belt warning system to 
induce an unbelted occupant to buckle up, the warning must be 
noticeable enough to attract the occupant's attention, or, for a 
warning directed at the driver, the driver's attention. However, if the 
warning is overly intrusive, consumers may not accept the 
technology.\194\ Therefore, the warning must be noticeable enough to 
prompt occupants to buckle their seat belts, but not so intrusive that 
the public does not accept the warning system, or that an occupant will 
circumvent or disable it. Consumer acceptance of any eventual seat belt 
warning requirements is an important consideration, given the potential 
safety benefits of rear seat belt warnings, the history of seat belt 
warning technologies, and the fact that consumers have not yet had 
widespread exposure to rear seat belt warnings. NHTSA is especially 
aware of this concern, given the agency's experience with public and 
Congressional backlash in the 1970s over the ignition interlock and 
continuous warning buzzer regulations.
---------------------------------------------------------------------------

    \194\ DOT 2009 Seat Belt Study at 2; Transportation Research 
Board Study at 8.
---------------------------------------------------------------------------

    We also noted research by NHTSA and others suggesting that 
consumers would accept the new technology. The 2004 Transportation 
Research Board Report observed that ``the data available to date 
provide strongly converging

[[Page 61705]]

evidence in support of both the potential effectiveness and consumer 
acceptance of many new seat belt use technologies[.]'' \195\ As part of 
the research for the report, NHTSA conducted focus-group interviews 
with part-time and hard-core nonusers. The report noted that ``many 
part-time users interviewed by NHTSA--the primary target group for the 
technology--were receptive to the new systems. Nearly two-thirds rated 
the reminders ``acceptable,'' and approximately 80 percent thought that 
they would be ``effective.'' \196\ The ANPRM also pointed to a 
telephone survey of drivers of vehicles with and without a rear seat 
belt warning system that NHTSA conducted in 2015.\197\ The rear warning 
systems in those vehicles had characteristics that were similar to the 
proposed requirements: a visual warning on start-up and an audio-visual 
change-of-status warning. The survey found, among other things, that 
81% of drivers of vehicles with a rear seat belt warning were ``very 
satisfied'' with the system; less than 2% were dissatisfied. Among 
drivers of vehicles without a rear seat belt warning, attitudes towards 
rear belt warnings were generally positive as well: a majority (55%) 
indicated that it was important to them that their next vehicle be 
equipped with a rear belt warning system.
---------------------------------------------------------------------------

    \195\ Transportation Research Board Study at 75-76.
    \196\ Id. at pg. 10.
    \197\ Paul Schroeder & Melanie Wilbur, Survey of Principal 
Drivers of Vehicles with a Rear Seat Belt Reminder System. 
Washington, DC: National Highway Traffic Safety Administration 
(2015). The vehicles with seat belt warning systems were Volvos and 
certain Cadillac and Chevrolet models.
---------------------------------------------------------------------------

Comments
    Several commenters believed that consumers would accept rear seat 
belt warnings. Commenters said that NHTSA's research shows that a large 
proportion of the consumer population will accept rear seat belt 
warnings and it noted that at the time of the interlock issue in the 
1970s, seat belt use rates were much lower than today, and a larger 
proportion of the population were hard-core nonusers. A commenter 
stated that its survey of 2,000 drivers showed that 70 percent favored 
a law requiring seat belt reminders that continuously chime until the 
seat belt is buckled, including rear seat passengers.\198\ Another 
commenter noted a 2012 IIHS survey showing that most motorists 
supported enhanced belt reminders that were ``more persistent and 
intense'' than what most automakers offered at the time.\199\ The 
commenter also noted the results of NHTSA's 2015 survey. Another 
commenter said that IIHS has found that the majority of drivers in the 
U.S. who transport passengers would accept a rear seat belt reminder 
system.\200\ This study found that parents believed an audible alert to 
be especially useful in alerting the driver to a child unbuckling in 
the back seat during a trip. A commenter suggested that consumers would 
accept R16-conforming systems.
---------------------------------------------------------------------------

    \198\ Citing www.norc.org/Research/Projects/Pages/underutilized-strategies-in-traffic-safety-results-of-a-nationally-representative-survey.aspx (last accessed Oct. 25, 2021).
    \199\ Citing Highway Loss Data Inst., Ins. Inst. for Highway 
Safety, Unbelted: Adults Admit They Often Skip Belts in Rear Seat, 
52 Status Rep. 1, 3 (Aug. 3, 2017), available at www.iihs.org/api/datastoredocument/status-report/pdf/52/5 (last accessed Oct. 25, 
2021).
    \200\ Citing David G. Kidd & Anne T. McCartt (2014) Drivers' 
Attitudes Toward Front or Rear Child Passenger Belt Use and Seat 
Belt Reminders at These Seating Positions, Traffic Injury 
Prevention, 15:3, 278-286, DOI: 10.1080/15389588.2013.810333.
---------------------------------------------------------------------------

    One commenter said that further studies are necessary because there 
is insufficient data on consumer acceptance.
Agency Response
    NHTSA has tentatively concluded that the proposed warning system 
would be acceptable to consumers in light of the specific 
characteristics of the proposed warning signals, real-world experience 
with seat belt reminder systems, and research and consumer surveys by 
NHTSA and others.
    We believe that the proposed requirements are specified so that the 
potential for consumer disapproval is minimized. Our intent was to 
specify minimum warning requirements that would result in an effective 
yet acceptable warning. With respect to the warning on start-up, we 
propose requiring only a visual warning, and not a more intrusive 
audible alert. The 60-second duration is comparable to the visual rear 
seat belt warnings provided by currently deployed systems. For example, 
the visual rear belt warning in some MY2022 vehicles lasts for at least 
60 seconds.\201\ The change-of-status warning would involve an audio-
visual alert lasting at least 30 seconds. While most vehicle models 
currently available in the U.S. with rear seat belt warning systems 
have a change-of-status warning that meets this 30-second minimum 
duration, we are aware of two available models that exceed this 
duration for the rear change-of-status warning. False positives would 
also be minimized because the positive-only compliance option only 
necessitates a buckle sensor, not occupant detection, which is more 
prone to false positives.
---------------------------------------------------------------------------

    \201\ We identified three manufacturers that produce vehicles 
with visual warnings that last for at least 60 seconds. One 
manufacturer provides vehicles where the visual warning stays active 
until the belt is fastened.
---------------------------------------------------------------------------

    Recent field experience also suggests that consumers would accept 
the proposed requirements. As noted earlier, an increasing number of 
vehicles sold in the United States have rear seat belt warning systems; 
based on 2022 Purchasing with Safety in Mind: What to Look For When 
Buying a Vehicle information, 46.9% of the total vehicle projected 
sales are equipped with rear SBWS.\202\ Moreover, in connection with 
the 2010 RFC, GM commented that it has not received any complaints 
about its rear seat belt warning system in either the United States or 
Europe,\203\ and Volvo indicated that it had found a high level of 
acceptance for its system.\204\ In addition to this, many OEMs have 
implemented enhanced seat belt warnings for the front outboard seats 
over the past two decades. Consumers' acceptance of these warnings also 
suggests that they would accept warnings for the rear seats.
---------------------------------------------------------------------------

    \202\ In the ANPRM it was 13% based on MY2019 vehicle data.
    \203\ See Docket No. NHTSA-2010-0061 (GM comment).
    \204\ See Docket No. NHTSA-2010-0061 (Volvo comment).
---------------------------------------------------------------------------

    Finally, in addition to the research noted in the ANPRM we note the 
studies cited by the commenters that support our tentative conclusion 
that consumers would accept the proposed warnings. In 2012, IIHS 
conducted a national telephone survey of drivers and passengers about 
seat belt use. Using this survey data, it proceeded to conduct several 
studies.
    One study, cited by the commenters, was on the attitudes towards 
seat belt use and in-vehicle technologies for encouraging seat belt 
use.\205\ All respondents were asked questions regarding their belt use 
habits and perceptions of different types of seat belt interlocks. 
Part-time belt users and nonusers were additionally questioned about 
different types of reminders and reminder strategies. The survey found 
that enhanced reminders are more acceptable than seat belt interlocks 
and are viewed as having the potential to be as effective as interlocks 
if sufficiently persistent. A larger proportion of part-time belt users 
and nonusers said they would be more likely to buckle up in response to 
auditory and haptic reminders than visual reminders. More

[[Page 61706]]

than two-thirds of part-time belt users and at least one-third of 
nonusers said they would be more likely to buckle up in response to 
seat belt reminders that become more intense or continue indefinitely; 
these reminders would be acceptable to about half of part-time belt 
users and around one-fifth of nonusers.
---------------------------------------------------------------------------

    \205\ Kidd, McCartt, & Oesch. Attitudes Towards Seat Belt Use 
and In-Vehicle Technologies for Encouraging Belt Use. Insurance 
Institute for Highway Safety. January 2013. The study over-sampled 
part-time belt users and nonusers.
---------------------------------------------------------------------------

    Another study cited by the commenters used the same survey that 
also collected information about drivers' attitudes towards passenger 
belt use and belt reminders for front passengers and children in back 
seats.\206\ This study used the 477 respondents (of the 1,218 total 
surveyed) that were drivers who transport a front-seat passenger at 
least once a week and 254 were drivers who transport an 8- to 15-year-
old child in the back seat. The respondents were asked about their 
attitudes toward seat belt use by their front passengers or rear child 
passengers and preferences for different passenger belt reminder 
features. The study found that nearly every driver who transports 
children in the back seat would encourage their belt use, regardless of 
the driver's belt use habits. Most drivers who transport front 
passengers wanted passenger seat belt reminders to encourage passengers 
to buckle up. As far as signal characteristics, the study found that 
front and rear passenger reminder signals that last indefinitely would 
be acceptable to most drivers who transport these passengers, and that 
an audible alert may be especially useful to alert drivers to children 
unbuckling in the rear seat during a trip.
---------------------------------------------------------------------------

    \206\ Kidd, D.G. and McCartt, A.T. 2013. Drivers' attitudes 
toward front or rear child passenger belt use and seat belt 
reminders at these seating positions. Insurance Institute for 
Highway Safety, January 2013.
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    We therefore tentatively conclude that consumers would accept the 
proposed warnings. NHTSA recognizes that there is some proportion of 
the public that may not desire a rear belt warning system.\207\ 
However, based on extensive research by NHTSA and others, we agree with 
commenters that consumers are more accepting of seat belt warnings now 
than in the 1970s.\208\ We are also mindful of Congress's repeal of the 
duration limitation on the audible warning for the driver's seat belt, 
as well as its directive to NHTSA to initiate a rulemaking for rear 
seat belt use systems. We believe this likewise suggests that the 
public would be amenable to appropriately specified warnings. NHTSA 
welcomes public comment on this issue.
---------------------------------------------------------------------------

    \207\ For example, in NHTSA 2015 phone survey, for drivers of 
vehicles without a rear belt warning, 23% found their vehicle's seat 
belt warning (i.e., for the front outboard passenger seats) 
annoying, and 16% would not need or want a seat belt warning system 
in their vehicle.
    \208\ See also, e.g., Highway Loss Data Inst., Ins. Inst. for 
Highway Safety, Unbelted: Adults Admit They Often Skip Belts in Rear 
Seat, 52 Status Rep. 1, 3 (Aug. 3, 2017) (indicating that most rear 
belt nonusers are not hard-core nonusers).
---------------------------------------------------------------------------

G. Technological and Economic Feasibility

    The ANPRM sought comment on the technological and economic 
feasibility of rear belt warning systems.
Comments
    Several commenters stated that rear warnings are technically 
feasible. Four commenters stated that rear warning requirements in 
foreign markets show that such systems are technically feasible and 
available. Two commenters also noted that rear reminders are already 
available in a number of makes and models in the United States, with a 
commenter noting that Volvo has been offering such a system in the 
United States since 2009.
    A commenter said that because technological complexity and cost 
will depend on the specifics of the particular system, NHTSA should 
provide OEMs flexibility by establishing baseline performance 
requirements with compliance options that would allow for more advanced 
system characteristics.
    Another commenter stated that buses present challenges for a rear 
seat belt warning system with respect to the number of passengers and 
harshness of the interior environment. The commenter also said that it 
would be difficult integrating a passenger seat system with rear seat 
belt warnings that are the same as the OEM driver and copilot warning 
system, so that the warnings may not match. The commenter said that 
there are seat belt warning systems being developed that utilize 
wireless technology and such a system would be less complex than a 
wired electrical connection system. The limitation of a wireless system 
is the battery life, and more system features such as individual 
passenger alerts would reduce battery life further. However, a battery-
operated wireless system would be much simpler for large vehicles with 
many passengers, as it would reduce the need for complex wiring 
systems. Another commenter believed that larger vehicles with many rear 
designated seating positions could present technical challenges, 
including the ability of a system to differentiate between objects that 
might be placed on seats and actual passengers of various weights and 
sizes.
Agency Response
    NHTSA has tentatively concluded that the proposed requirements are 
technologically and economically practicable.\209\ Based on 2022 
Purchasing with Safety in Mind: What to Look For When Buying a Vehicle 
information, 46.9% of the total U.S. vehicle projected sales are 
equipped with rear seat belt warning systems. For vehicles that do not 
already incorporate a rear seat belt warning system, the positive-only 
compliance option would require seat belt sensors, wiring, and display 
adjustments. All of this technology is readily available. The seat belt 
latch sensors that would be needed for all three systems are already 
used by many manufacturers to comply with the existing driver seat belt 
requirements. Occupant detection might present technological challenges 
but would not be necessary for a positive-only warning system. As we 
explain in more detail in Section XIV, Overview of Costs and Benefits, 
we estimate that the minimum cost to comply with the rear seat belt 
warning requirements (the positive-only system) would be $167.8 
million. This is based on a per-vehicle cost of $19.59 for 53.1% of 16M 
affected new vehicles. As explained later, our preliminary regulatory 
impact analysis indicates that the proposed requirements are cost-
beneficial across a range of discount rates and reasonable 
effectiveness estimates.
---------------------------------------------------------------------------

    \209\ See also Section XIV, Overview of Benefits and Costs.
---------------------------------------------------------------------------

    As we noted in the ANPRM, implementing a visual warning may require 
physical redesign of the instrument panel. Such redesign would have to 
take into account visibility, interaction with existing signals and 
displays, available space on the instrument panel, and effectiveness, 
as well as other factors. In some instances, a visual signal might be 
displayed as a telltale on the instrument panel or on the vehicle's 
information display screen. Manufacturers would also have to determine 
whether driver and rear passenger seat belt warning visual signals 
would be treated the same.
    We also recognize that vehicles with many rear designated seating 
positions may present some challenges, but we have tentatively 
concluded that they should be subject to the proposed requirements 
(with the exception of school buses) because those vehicles would be at 
least as likely, if not more likely, to have rear occupants. In 
addition, multiple rear seats may increase the difficulty of the driver 
in ascertaining rear seat belt use, so a warning could prove especially 
useful

[[Page 61707]]

in these vehicles. We also recognize the intent of the MAP-21 
requirements in improving protection for rear occupants, and given the 
proven benefits of seat belts, believe the warning should be broadly 
applied. Our main motivation for including small buses is to capture 
large capacity passenger vans; these vehicles might utilize the option 
of a warning that indicates the number of seat belts fastened. However, 
we do seek comment on whether it would be appropriate to exclude 
additional vehicle types.
    Overall, we believe that the proposed compliance options would 
provide manufacturers with the flexibility to innovate and develop new 
technologies, while also ensuring a minimum level of safety. We seek 
comments on the practicability of the proposed compliance options.

XI. Warning Requirements for Front Outboard Seats

    We propose several changes and enhancements to the seat belt 
warning requirements for the front outboard seats. There are three main 
changes we are proposing.
    First, we are proposing a requirement for an audio-visual warning 
on vehicle start-up for the front outboard passenger seat. Currently, 
the standard requires a short duration (4-60 seconds, depending on the 
compliance option) audio-visual seat belt warning on vehicle start-up 
for the driver's seat belt for most vehicles with a GVWR under 10,000 
lb (excluding medium-sized buses), but not for any other front seats. 
The vast majority of the vehicles being sold today (approximately 96.6% 
of the fleet, according to information submitted by vehicle 
manufacturers to NHTSA for NCAP in MY 2022) already provide a seat belt 
warning for the front outboard passenger seat. We propose to require a 
seat belt warning for this seat to ensure that all vehicles have this 
important safety feature.
    Second, we propose to close the current gap for a driver's seat 
belt warning in medium-sized buses. We are unaware of any such buses 
that do not already provide a driver's seat belt warning; requiring 
this would ensure that they continue to have a driver seat belt warning 
in the future.
    Third, we propose several changes to the current requirements for 
the audio-visual warning signal that currently apply to the driver's 
seat that would also apply to the front outboard passenger seat. The 
most notable of these is that we propose to require that the audio-
visual warning on vehicle start-up last until the belts at any occupied 
front outboard seats are fastened, and a change-of-status warning for 
any front outboard seat that would also last until the seat belt is 
refastened (unless a front door is open).
    These proposals are explained in more detail below.

A. Seat Belt Warning for Front Outboard Passenger Seat

    This document proposes to require an audio-visual seat belt warning 
for any front outboard passenger seat.\210\ FMVSS No. 208 currently 
requires an audio-visual seat belt warning for the driver's seat in 
passenger cars and trucks, buses, and MPVs with a GVWR of 4,536 kg 
(10,000 lb) or less, except for buses with a GVWR greater than 3,855 kg 
(8,500 lb) and less than or equal to 4,536 kg (10,000 lb). NHTSA's 
regulations currently do not require seat belt warnings for any seating 
position other than the driver's seat.\211\ Although the ANPRM did not 
discuss extending the seat belt warning requirements to any front 
passenger seats, two commenters recommended that NHTSA amend FMVSS No. 
208 to require a seat belt warning for all front seats, and another 
commenter recommended adopting the ECE R16 requirements for front 
outboard seating positions. ECE R16 requires an audio-visual seat belt 
warning for the front outboard passenger seat.\212\
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    \210\ In Section XIII.C we discuss the potential for more than 
one front outboard passenger seat in ADS-equipped vehicles.
    \211\ See, e.g., Interpretation Letter from NHTSA to R. Lucki, 
July 24, 1985 (``Thus, the intent was to require a warning system 
for only the driver's position.'').
    \212\ Section 8.4.1.1.
---------------------------------------------------------------------------

    We believe there is good reason to do so, as the reasons for 
ensuring the driver is buckled apply equally to front outboard 
passenger. About 10.4% of right-front passengers do not always fasten 
the belt \213\ and unbelted occupants are overrepresented in fatal 
crashes. The lack of a seat belt warning requirement for the front 
outboard passenger seat dates to the 1970s, when seat belt use rates 
were much lower and seat belt warnings were not as acceptable to 
consumers as they are today. Further, almost all (96.6%) vehicles 
offered for sale in the U.S. that participate in the NCAP information 
request are already equipped with a seat belt warning at this position, 
so requiring such a warning would ensure that all vehicles be equipped 
with a seat belt warning at this position.
---------------------------------------------------------------------------

    \213\ National Center for Statistics and Analysis. (2021, 
February). Seat belt use in 2020--Overall results (Traffic Safety 
Facts Research Note. Report No. DOT HS 813 072). National Highway 
Traffic Safety Administration.
---------------------------------------------------------------------------

    We are proposing an audio-visual warning on vehicle start-up 
because research by NHTSA and others suggests that seat belt warnings 
that use an audio-visual signal are more effective than visual warnings 
alone. In addition, the potential technological, consumer acceptance, 
and cost issues associated with requiring an audible warning for a rear 
seat belt warning do not apply to an audible warning for the front 
outboard passenger seat because, although the audible warning would 
entail use of occupant detection technology, most vehicles are already 
equipped with both an audible seat belt warning and occupant detection 
for the front outboard passenger seat. This proposal would not require 
that the audible warning be specific to either the driver or front 
outboard passenger seat; therefore, manufacturers could utilize the 
same audible warning for both seats as is done with some of the 
existing front belt warning systems.
    The proposed front outboard passenger seat requirements would apply 
to all the vehicles to which the proposed rear belt warning 
requirements would apply: all front outboard designated seating 
positions in passenger cars, and all front outboard designated seating 
positions certified to a compliance option requiring seat belts in 
trucks, MPVs, and buses with a GVWR of 4,536 kg (10,000 lb) or 
less.\214\ We have tentatively decided not to extend the seat belt 
warning requirements to front center seats because our preliminary 
regulatory impact analysis found that a system for the front center 
seat without occupant detection would provide limited benefit due to 
the low occupancy of the front center seat and the limited number of 
vehicles in the fleet with a front center seat. See Section XIII, 
Regulatory Alternatives, and the PRIA for a more detailed analysis.
---------------------------------------------------------------------------

    \214\ There are some compliance options for certain trucks and 
MPVs that permit passive protection in lieu of seat belts at the 
front outboard seating positions. See S4.2.3 (compliance options for 
trucks and MPVs weighing between 8,500-10,000 lb); S4.2.6 & S4.2.1.1 
(compliance options for walk-in van-type trucks and vehicles 
designed to be sold exclusively to the U.S. Postal Service 8,500 lb 
and less).
---------------------------------------------------------------------------

Occupant Detection
    Because we are proposing an audio-visual warning, we are also 
proposing to require that any front outboard passenger seat be equipped 
with an occupant detection system; an audio-visual warning is typically 
only appropriate for occupied seats because having an audible warning 
activate for an unoccupied seat could be a nuisance

[[Page 61708]]

for the occupants and might desensitize them to the warning or lead 
them to circumvent the system. Requiring occupant detection is 
consistent with Euro NCAP, which requires occupant detection for the 
front passenger seat belt warning. In the United States, occupant 
detection is already widely deployed in the front outboard passenger 
seat, either as part of an advanced air bag system, or as part of a 
voluntary seat belt warning system.\215\ Based on compliance and 
consumer information data submitted to NHTSA by vehicle manufacturers, 
NHTSA is not aware of any vehicles to which the proposed requirements 
would apply that are not already equipped with occupant detection for 
this seating position. This demonstrates that the technology is 
feasible and that an occupant detection requirement would not result in 
any additional costs.\216\ It would also ensure that vehicles produced 
in the future would be equipped with the technology.
---------------------------------------------------------------------------

    \215\ Occupant detection is utilized by the advanced air bags to 
properly classify the occupant in the seat (e.g., child, adult, 
small-statured adult) so that the advanced frontal air bag systems 
can determine if and with what level of power the front air bag will 
inflate. We also believe that occupant detection is voluntarily used 
in the front passenger seat to avoid having an audible seat belt 
warning activate for an unoccupied seat.
    \216\ Occupant detection systems are less challenging for the 
front outboard passenger seat than for the rear seats because the 
front outboard passenger seat is not typically subject to as many of 
the potential complications to occupant detection (such as large 
occupants spanning multiple seating positions). There may be 
infrequent situations where occupant detection sensors may 
incorrectly register the presence of an occupant when the seat is 
unoccupied (e.g., mistaking cargo for an occupant). However, if 
cargo placed on the seat causes a false occupant detection reading 
and inadvertent activation of the front passenger seat belt warning 
signal, the driver can readily discern it is a false reading and can 
easily either place the cargo on the floor or fasten the seat belt 
to disable the signal.
---------------------------------------------------------------------------

    We propose that the warning system consider this seating position 
``occupied'' when an occupant who weighs at least 46.7 kg (103 lb) and 
is at least 139.7 cm (55 in) tall is seated in the seat. These values 
are the weight and height criteria currently specified in FMVSS No. 208 
(S29.1(f)) for a person who is used as an alternative for the 5th 
percentile adult female test dummy for compliance testing of advanced 
air bag systems utilizing static suppression. These criteria are 
consistent with the agency's recommendation on not transporting 
children in the front seat, as well as Euro NCAP and the ECE R16 test 
procedures. As described below, in connection with the proposed test 
procedures (Section XII.B, Test Procedures), the agency would use 
either a person or test dummy meeting these criteria.

B. Driver's Seat Belt Warning for Medium-Sized Buses

    FMVSS No. 208 currently does not require buses with a GVWR greater 
than 3,855 kg (8,500 lb) and less than or equal to 4,536 kg (10,000 
lb), or with a GVWR less than or equal to 3,855 kg (8,500 lb) and an 
unloaded weight greater than 2,495 kg (5,500 lb), to be equipped with a 
driver seat belt warning. We are proposing to amend FMVSS No. 208 to 
close this loophole.
    We are unaware of any such buses that do not already have a driver 
seat belt warning that meets or surpasses the warning specified in 
FMVSS No. 208. Accordingly, we believe this requirement would have 
minimal, if any, costs or benefits. Requiring a driver seat belt 
warning for these buses would ensure that they continue to have a 
driver seat belt warning in the future. We invite comments on this 
proposal and these assumptions.

C. Amendments to the Current Warning Signal Requirements

    The current driver's seat belt warning requirements provide 
manufacturers with two compliance options.\217\ The first option 
requires that if the key is in the ``on'' or ``start'' position and the 
seat belt is not in use, the vehicle must provide a visual warning for 
at least 60 seconds, and an audible warning that lasts 4 to 8 seconds. 
Under the second option, when the key is turned to the ``on'' or 
``start'' position, the vehicle must provide a visual warning for 4 to 
8 seconds (regardless of whether the driver seat belt is fastened) and 
an audible warning lasting 4 to 8 seconds if the driver seat belt is 
not in use.
---------------------------------------------------------------------------

    \217\ S7.3.
---------------------------------------------------------------------------

    We propose to modify these requirements in three main ways. First, 
we propose a single compliance option that requires a start-of-trip 
audio-visual warning that lasts until the seat belt at any occupied 
front outboard seat is fastened. Second, we propose to require an 
audio-visual change-of-status warning if a buckled belt at either of 
these seating positions is unfastened in the middle of a trip. Third, 
we propose some additional requirements for the audible warning related 
to increasing the duration (for example, specifying a minimum 0.20 duty 
cycle for the audible warning); however, we generally do not propose 
requirements beyond what is currently in the standard related to other 
aspects of the warning. These proposals are explained in more detail 
below.
1. Increasing the Duration of the Audio-Visual Warning on Vehicle 
Start-Up
    The current eight-second limitation on the duration of the audible 
warning was based on a statutory restriction, enacted in 1974, that 
limited the length of the audible warning. MAP-21 repealed this 
limitation. In light of MAP-21's repeal of the 8-second limitation, the 
ANPRM sought comment on removing the corresponding limitation in FMVSS 
No. 208.
Comments
    Several commenters supported removing this restriction. One 
commenter said that removing it would provide manufacturers with 
greater regulatory certainty in deploying enhanced seat belt reminders, 
although, the commenter stated, there needs to be an upper bound on the 
duration of the required warning to ensure an objective and repeatable 
test for the purposes of vehicle certification. The commenter 
recommended maintaining the current 4- to 8-second warning thresholds 
defined in table 4 of the FMVSS No. 208 laboratory test 
procedures.\218\ Another commenter encouraged NHTSA to allow enhanced 
seat belt reminder systems as a compliance option, possibly in lieu of 
the currently required 4 to 8 second alarm. A commenter recommended 
increasing the minimum duration for the audible warning to at least 90 
seconds because the current audible signal duration upper limit is 
ineffective for increasing seat belt use (and cited studies to support 
this recommendation). Related to this, a commenter stated that a survey 
of 2,000 drivers it commissioned showed that 70 percent favored a law 
requiring seat belt reminders that continuously chime until the seat 
belt is buckled, including rear seat passengers,\219\ and a commenter 
noted a 2012 IIHS survey showing that most motorists supported enhanced 
belt reminders that were ``more persistent and intense'' than what most 
automakers offered at the time.\220\
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    \218\ The laboratory procedures are not part the regulatory 
text. Published separately by NHTSA's Office of Vehicle Safety 
Compliance, they are intended to provide laboratories contracted by 
NHTSA with additional guidelines for obtaining compliance test data.
    \219\ Citing www.norc.org/Research/Projects/Pages/underutilized-strategies-in-traffic-safety-results-of-a-nationally-representative-survey.aspx (last accessed Oct. 25, 2021).
    \220\ Citing Highway Loss Data Inst., Ins. Inst. for Highway 
Safety, Unbelted: Adults Admit They Often Skip Belts in Rear Seat, 
52 STATUS REP. 1, 3 (Aug. 3, 2017), available at www.iihs.org/api/datastoredocument/status-report/pdf/52/5 (last accessed Oct. 25, 
2021).
---------------------------------------------------------------------------

    On the other hand, a commenter recommended that NHTSA incorporate

[[Page 61709]]

the Euro NCAP enhanced seat belt reminder requirements in the U.S. NCAP 
program if the agency wants to encourage enhanced seat belt reminders 
that provide driver warnings beyond 8-seconds.
    A commenter recommended that the front and rear requirements be 
consistent with respect to the required duration of the audible 
warning.
Agency Response
    NHTSA has tentatively decided to increase the required duration for 
the audio-visual warning provided on vehicle start-up to occupants of 
the front outboard seats. The extremely short duration currently 
required for the driver's seat belt warning--which originated in the 
early 1970s--is outdated.\221\ It was premised on the since-repealed 
eight-second statutory limitation on the audible warning duration, 
then-existing low seat belt use rates, and consumer resistance to 
enhanced warnings, and the related lack of such warnings in most 
vehicles. These circumstances no longer hold. There are several 
respects in which the current requirements are therefore not relevant 
to today's market.
---------------------------------------------------------------------------

    \221\ What is now the second compliance option (S7.3(a)(2)) was 
added to the standard in 1974, and what is now the first compliance 
option (S7.3(a)(1)) was added to the standard in 1991. See 39 FR 
42692 (Dec. 6, 1974); 56 FR 3222 (Jan. 29, 1991). The second (and 
original) compliance option requires an ``advisory'' visual warning 
that is required to activate regardless of whether the seat belt is 
buckled; the purpose for this, as NHTSA explained in 1974, was so 
the ``reminder would remain effective even if the belt were disabled 
to silence the audible warning.'' 39 FR 42692. (A later rulemaking 
preamble also suggested that this would serve to remind other 
occupants to buckle their belts. 56 FR 3222.) The 4- to 8-second 
duration was selected ``because an irritating light can be easily 
ignored or disabled, a visual signal can effectively serve only a 
reminder function, and as such, it should be as simple as possible. 
The NHTSA concludes that a 4- to 8-second reminder is best 
calculated to accomplish the advisory function.'' 39 FR 42692. The 
first compliance option was added in response to a petition for 
rulemaking from General Motors to allow manufacturers to use a 
safety belt warning system meeting the requirements for automatic 
safety belt warning systems as an alternative to the warning system 
that was specified for manual belt systems.
---------------------------------------------------------------------------

    First, the existing requirements are significantly exceeded by the 
warnings provided in current vehicles. Although NHTSA did not 
previously have the authority to require a seat belt warning with an 
audible signal lasting more than 8 seconds, starting in at least the 
early 2000s, manufacturers voluntarily began providing enhanced audio-
visual warnings exceeding the FMVSS No. 208-minimum durations.\222\ In 
order to get a better sense of the warning durations in currently sold 
vehicles, NHTSA analyzed data on the seat belt warning durations for MY 
2022 vehicle models provided to the agency by vehicle manufacturers for 
NCAP; this data covers most vehicles offered for sale in the U.S. for 
MY 2022 with a GVWR of 4,536 kg (10,000 lbs.) or less.\223\ In total, 
we received seat belt duration information on over 500 different 
vehicle models.\224\ For each vehicle model, we looked at the warning 
durations for the visual and audible warnings for the driver and front 
outboard passengers seat belts, as well as the reported projected sales 
for that model as a proportion of the total projected sales for all of 
the vehicle models for which data was provided to NHTSA. We then 
tabulated this data to determine how warning durations were distributed 
across the new vehicle fleet. Specifically, we divided the range of 
warning durations provided--ranging from six seconds to indefinitely 
long--into intervals. For each interval, we summed up the projected 
vehicle sales of all the vehicle models providing a warning with a 
duration falling within that interval and divided that sum by the total 
projected sales of all vehicle models. In general, we found that 
roughly half of new light vehicles provide a visual warning that lasts 
until the belt is fastened and an audible warning that lasts at least 
two minutes (120 sec). In the discussion later, we discuss this data in 
more detail. We also looked at the warning durations provided in new 
vehicles tabulated by vehicle model instead of projected sales. The 
results are generally the same, although there are some differences 
compared to the vehicle sales analysis presented here. These data and 
results are presented in appendix A.
---------------------------------------------------------------------------

    \222\ See Section III, Regulatory and Legislative History. 
Similarly, an advisory warning for other seating positions is not 
necessary because if the proposal is adopted the front outboard 
passenger seat and the rear seats would have warnings specifically 
for those seats.
    \223\ See supra note 38.
    \224\ Specifically, we received information on driver visual 
warning duration for 599 models for; driver audible warning duration 
for 599 models; front outboard passenger visual warning duration for 
564 models; and front outboard passenger audible warning duration 
for 558 models. The number of models differs because some models for 
which a vehicle manufacturer submitted information did not include 
complete information on the front outboard seat belt warnings and 
some vehicles are not equipped with a front passenger seat belt 
warning system.
---------------------------------------------------------------------------

    With respect to the driver visual warning, the majority of new 
vehicles--over 60% as a percentage of total projected sales volume--
have a warning that lasts until the belt is fastened (Figure 3). The 
remainder of the fleet is about equally divided between a 5-minute (300 
second) visual warning and a visual warning lasting at least 1.5 
minutes, but less than 2 minutes (90-119 seconds).\225\ Less than 2% of 
the fleet has a warning lasting less than 1.5 minutes (90 sec). The 
results for the front outboard passenger visual warning are essentially 
the same as for the driver seat belt visual warning. See Figure 4.
---------------------------------------------------------------------------

    \225\ The 300-329 second interval consists of vehicles from just 
one manufacturer, all of which have a 300-second reminder. The 90-
119 second interval includes a variety of different-make vehicle 
models with different reminder durations.

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[[Page 61710]]

[GRAPHIC] [TIFF OMITTED] TP07SE23.002

    With respect to the driver audible warning, all of the vehicles for 
which NHTSA had data have an audible warning lasting longer than the 
regulatory minimum of 4 seconds. A small number of vehicles (about 1% 
as a share of total projected sales volume) have an audible warning 
that last six or eight seconds.\226\ See Figure 5. Thus, a very small 
proportion of the current vehicle fleet provide the very low-duration 
audible warning currently required by FMVSS No. 208.
---------------------------------------------------------------------------

    \226\ For the driver audible warning, the 0-29 second interval 
consists of a number of different vehicle makes, all of which 
provide either a six or eight-second warning.
---------------------------------------------------------------------------

    Instead, almost all new vehicles provide a driver audible warning 
that significantly exceeds the current minimum. Overall, about 99% of 
vehicles (by share of total projected sales volume) provide an audible 
warning that lasts at least 30 seconds, and about 92% of vehicles 
provide an audible warning that lasts at least 1.5 min (90+ sec). See 
Figure 6. About half of the fleet (47%) provide an audible warning that 
lasts two minutes or more (120+ s). Of the vehicles that provide an 
audible warning with a finite length, the sales-weighted mean is 2.9 
minutes (174 seconds) and the median is 1.7 minutes (100 seconds).
[GRAPHIC] [TIFF OMITTED] TP07SE23.003

[[Page 61711]]

    Turning to the specific durations provided for the driver audible 
seat belt warning, about half of new vehicles (45.5% as a share of 
total projected sales volume) provide a warning that lasts 90-to-119 s 
(1.5 s-1.98 s).\227\ See Figure 5. The longest-duration audible 
warnings, provided by two vehicle manufacturers, last until the belt 
has been buckled (accounting for about 8% of new vehicles sold). The 
longest limited-duration audible warnings, lasting 5 and 8 minutes (300 
and 480 seconds) are provided by two manufacturers (about 22% of new 
vehicles).\228\ The other duration that is used in a non-trivial share 
of new vehicles is from 4 min-4.5 min (240 s-269 s) (about 12% of new 
vehicles).\229\ The corresponding analysis for the front outboard 
passenger seat belt warning is very similar.\230\ See Figure 7 and 
Figure 8.
---------------------------------------------------------------------------

    \227\ 90, 96, 100, and 108 seconds are the most used durations 
in that range, but there are other durations too. 100 seconds is the 
most used.
    \228\ The only warning duration provided in the 300-329 sec 
interval is 300 sec.
    \229\ Specifically, these are all on vehicles from one 
manufacturer, which provide an audible warning lasting 261 s.
    \230\ The sale-weighted mean for the front passenger audible 
warning is 176.57 and the median is 96.
[GRAPHIC] [TIFF OMITTED] TP07SE23.004

    Second, we tentatively agree with IIHS that the current audible 
signal duration upper limit of eight seconds is ineffective for 
increasing seat belt use. From the vehicle survey data presented here, 
it is clearly not a factor affecting vehicle design. As discussed 
earlier in this preamble, front seat belt use rates have plateaued in 
recent years so that about 10% of front-row occupants do not always use 
a seat belt. Coupled with this, we note that approximately 83-89% of 
nonusers are part-time nonusers who would be open to using a belt.\231\ 
Although research may not yet have firmly established which exact 
system specifications are optimal,\232\ research by NHTSA and others 
suggests that audio-visual warnings are more effective than visual 
warnings alone and that longer duration warnings are more effective 
than shorter duration warnings.\233\ NHTSA's earlier research estimated 
that an enhanced reminder, on average, increased seat belt use three to 
four percentage points compared to the basic reminder currently 
required by FMVSS No. 208. IIHS in its comment cited recent research it 
had conducted that evaluated the effectiveness of three different 
driver's seat belt reminders. All of the reminders had a visual warning 
that persisted until the seat belt was fastened but had audible 
reminders of varying duration. The research found that, compared to a 
short intermittent audible reminder (specifically, three intermittent 
7-second audible reminders), an audible reminder with an indefinite 
duration increased seat belt use by 34%, and an audible reminder with a 
100-second duration increased seat belt use by 30%. However, we note 
that more than 90% of MY 2022 vehicles already have audible warnings of 
at least 90 seconds, but only about 8% have an indefinite reminder. For 
more information on these effectiveness estimates, see Section XIV, 
Costs and Benefits.
---------------------------------------------------------------------------

    \231\ It also might be the case that so-called ``hard-core'' 
nonusers, who comprise about 11-17% of nonusers, would use the belt 
if the reminder were sufficiently annoying, although, for the 
purposes of our effectiveness (and benefits) analysis, we 
conservatively assume that the increase in belt use would be due 
entirely to part-time nonusers.
    \232\ DOT 2009 Belt Warning Study, p. 1 (``Although improvements 
in seat belt use rates appear to result from ESBRs, there is not yet 
good evidence concerning what works best and why a given system may 
influence occupant behavior.'').
    \233\ See, e.g., DOT 2009 Belt warning Study, pp. 8, 46-49. See 
also David G. Kidd & Jeremiah Singer, The effects of persistent 
audible seat belt reminders and a speed-limiting interlock on the 
seat belt use of drivers who do not always use a seat belt. 
Insurance Institute for Highway Safety (2019) (``Persistent enhanced 
reminders with longer-lasting or more frequent auditory chimes have 
been found to be more effective for increasing seat belt use.'') 
(citing NHTSA research).
---------------------------------------------------------------------------

    Third, we tentatively believe that contemporary consumers would 
accept a longer warning. As we discussed earlier in this preamble, in 
the early 1970s, NHTSA faced consumer backlash when it required long-
lasting seat belt warnings. However, consumer behavior and attitudes 
have changed since then--seat belt use is more widespread, and 
opposition to using a seat belt is much less prevalent than it was in 
the 1970s. This is evidenced by MAP-21's repeal of the eight-second 
audible seat belt warning limitation, and by the fact that almost all 
light vehicles sold in the U.S. now feature relatively long duration 
visual and audible warnings for the front outboard seats. Research by 
NHTSA and others suggests that

[[Page 61712]]

consumers would potentially accept an appreciably longer duration 
warning. As we noted above in connection with the rear seat belt 
warning (Section X.F, Consumer Acceptance), NHTSA's research suggests 
that part-time belt users are receptive to seat belt warning 
technologies, including front seat belt warnings. Furthermore, more 
recent research by others suggests support for more persistent 
reminders. IIHS's research has found that, while public acceptance of 
intense reminders was a concern, seat belt reminders that become more 
intense or continue indefinitely would be acceptable to about half of 
part-time belt users and around one-fifth of nonusers.\234\ Another 
IIHS study found that, while its data was subject to some limitations, 
``most drivers who transport front passengers wanted . . . reminders 
that last indefinitely until the front passenger buckles up,'' 
``suggest[ing] that stronger front passenger reminders, such as those 
meeting Euro NCAP's design requirements, may be acceptable to most 
drivers who transport front passengers.'' \235\ We also note the 
studies cited by NSC and CAS suggesting strong support for more 
persistent--and even indefinitely long--reminders. At the same time, we 
do acknowledge that while enhanced warnings are potentially more 
effective, they are also more intrusive.\236\ They therefore present 
potential consumer acceptance challenges that may reduce their 
effectiveness.\237\ NHTSA's earlier research suggests that it may be 
challenging to design a warning system with effective yet acceptable 
characteristics,\238\ and that no clear consensus exists about which 
warning system features are most acceptable.\239\ It also noted that 
while it appears that a majority of the general public accepts seat 
belt reminders, the data on public acceptance is somewhat limited and 
anecdotal, and that resistance by a minority of the public could limit 
overall public acceptability.\240\ However, based on the best data 
available to us, we tentatively believe that consumers would accept an 
audio-visual front seat belt reminder with a significantly longer 
duration than the standard currently requires, including an indefinite 
duration.
---------------------------------------------------------------------------

    \234\ Kidd, McCartt, & Oesch. Attitudes Towards Seat Belt Use 
and In-Vehicle Technologies for Encouraging Belt Use. Insurance 
Institute for Highway Safety. January 2013, pp. 1-3. The study over-
sampled part-time belt users and nonusers. But see p. 3 (``Requiring 
all vehicles to have more intense enhanced reminders is a promising 
way to increase belt use among part-time belt users, but public 
acceptance still is a concern because the characteristics that make 
reminders more effective also are the characteristics that make them 
more annoying. It is not clear how intense a reminder needs to be to 
increase belt use among the remaining part-time belt users and non-
users and what trade-off in annoyance is acceptable.'') (citation 
omitted).
    \235\ Kidd, D.G. and McCartt, A.T. 2013. Drivers' attitudes 
toward front or rear child passenger belt use and seat belt 
reminders at these seating positions. Insurance Institute for 
Highway Safety, January 2013. But see id. at p. 13 (``Long-lasting, 
auditory front passenger reminders might not be acceptable to these 
drivers, so it is important to find ways to reduce the potential 
annoyance of front passenger reminders without compromising their 
effectiveness.'').
    \236\ DOT 2009 Belt Warning Study, supra n.36, p. 39 (drivers); 
p. 45 (passengers).
    \237\ See, e.g., DOT 2009 Seat Belt Study at 54, 58 (while 
research to date on front seat systems suggests that features such 
as a longer-lasting flashing visual warning might be more effective 
than a basic system, some warnings that may be more effective could 
also be more annoying to occupants).
    \238\ See DOT 2009 Seat Belt Study at 60.
    \239\ DOT 2009 Belt Warning Study, p. 8; Schroeder & Wilbur, 
supra, p. 33.
    \240\ N. Lerner et al. 2007. Acceptability and Potential 
Effectiveness of Enhanced Seat Belt Reminder System Features. DOT HS 
810 848. Washington, DC: National Highway Traffic Safety 
Administration, p. 41-42
---------------------------------------------------------------------------

    Fourth, the technology necessary to implement such an enhanced 
warning is already standard equipment on almost all light vehicles. An 
enhanced warning that activates for an unoccupied seat could be a 
nuisance that either desensitizes the occupants to the warning, or 
leads them to circumvent or defeat the warning. Enhanced warnings 
therefore generally need to work in conjunction with an occupant 
detection system. This makes light vehicle front outboard seats well-
suited for enhanced warnings, because almost all front outboard seats 
are already equipped with occupant classifications systems in order to 
comply with the advanced air bag requirements. Seat belt warnings for 
the front outboard seats are therefore capable of being activated only 
when an unbelted occupant is present, which greatly diminishes the risk 
of false warnings. Accordingly, increasing the reminder duration would 
entail minimal costs.
    Finally, a longer-duration is consistent with seat belt warning 
durations required or encouraged in other markets and ratings programs. 
ECE R16 requires that for the front seats there be a 30 second visual 
warning when the front seat belts are not fastened and the ignition is 
activated. It also requires an audio-visual warning that must activate 
for at least 30 seconds if the seat belt remains unfastened and 
specific onset criteria are met (e.g., distance traveled, speed, etc.). 
To prevent unnecessary signals, both ECE R16 and Euro NCAP require that 
the system be capable of detecting whether the front passenger seat is 
occupied. The Euro NCAP assessment protocol requires a visual signal 
that remains active until the seat belt is fastened, and a two-stage 
audible signal; the initial audible signal must not exceed 30 seconds 
and the final audible signal must be at least 90 seconds. Similar to 
Euro NCAP, under the IIHS seat belt reminder system ratings protocol, 
the primary audible reminder signal for the front outboard seats must 
be at least 90 seconds in total duration in order to obtain an 
``acceptable'' or ``good'' rating. Although ECE R16 does not require an 
indefinite reminder, such a reminder would comply with that standard, 
as they do not contain a maximum length.
    We are therefore proposing to increase the minimum duration of the 
audio-visual warning for the front outboard seat belts on vehicle 
start-up. In developing this proposal, we considered a range of 
alternative warning durations. At the upper end of the range is an 
indefinite reminder--a reminder that remains activated until the 
occupant fastens the seat belt. Short of this are reminders that have 
relatively long durations, but do not last indefinitely. Because there 
is a large range of durations that could be selected, in order to help 
structure the proposal (and aid comment) we considered the following 
``buckets'' of reminder durations, based on the front audible warning 
durations provided in MY 2022 light vehicles offered for sale in the 
U.S. as well as the durations specified in ECE R16, Euro NCAP, and the 
IIHS ratings protocol:
     Less than thirty seconds (less than required in Europe and 
provided in only about 1% of new vehicles offered for sale in the U.S. 
in MY 2022);
     30 seconds up to but not including 90 seconds (1.5 
minutes) (consistent with ECE R16, and provided in about 8% of MY 2022 
vehicles in the U.S.);
     90 seconds (1.5 minutes) up to but not including 2 minutes 
(consistent with Euro NCAP, and provided in about 46% of MY 2022 
vehicles in the U.S.);
     2 minutes (120 sec) up to (and including) 5 minutes (300 
seconds) (the approximate mid-range of the audible warning durations 
provided in MY 2022 vehicles in the U.S.);
     Greater than 5 minutes (300 sec) but not indefinite (which 
includes the longest limited-duration audible warning, 8 minutes (480 
sec) (provided in about 8% of new vehicles in the U.S.); and
     Indefinite duration (currently adopted by two vehicle 
manufacturers, accounting for about 8% of new vehicles in the U.S.).

[[Page 61713]]

    We have tentatively decided to propose requiring an audio-visual 
reminder that lasts until the belts are fastened at any occupied front 
outboard seating position, in light of the increase in roadway 
fatalities and the lack of improvement of front seat belt use rates. We 
also tentatively believe this is supported by the favorable ratio of 
part-time to hard-core seat belt nonusers, surveys indicating a 
significant level of acceptance for enhanced seat belt warnings, and 
the fact that a non-trivial share of currently sold vehicles have an 
indefinite-duration reminder. These vehicles incorporating the 
indefinite warning support the practicability of the proposal. 
Additionally, the small percentage of market penetration provides the 
greatest opportunity for potential benefit (see section XIII). We also 
believe that other warning signal characteristics--such as duty cycle, 
frequency, volume, or timbre--can be adjusted to balance effectiveness 
and consumer acceptance; manufacturers would have the flexibility to 
adjust these or other aspects of the warning, within certain limits, as 
discussed further below. We do not agree with Global that an upper 
bound on the warning duration is necessary for objectivity. The warning 
simply would be required to remain active as long as the belt were 
unfastened at an occupied seat; NHTSA's compliance test would 
necessarily have to stop at some point, but NHTSA could make the test 
time as long as it wanted and manufacturers would have to certify that 
the warning would be indefinite.
    NHTSA seeks comment on this proposal. If opposed to an indefinite 
warning, what data support limiting its duration? If NHTSA were to 
instead require an enhanced but limited-duration warning, how long 
should the warning be? We also seek comment from manufacturers (and 
others) about the basis for the warning durations provided in current 
vehicles, particularly the warnings that exceed the Euro NCAP duration 
(90 sec); for example, the basis for the 5-minute warning, or the 8-
minute warning, or the indefinite warning. We also seek comment on the 
effectiveness and consumer acceptance of the proposed and alternative 
durations. One reason a shorter duration could be more effective is 
that some seat belt nonusers might be more likely to habitually 
circumvent an indefinite-duration warning as opposed to a limited-
duration warning. However, such an assumption presupposes there is some 
limited duration for which a nonuser would be less likely to 
circumvent. What would such a duration be, and would it have a reduced 
effectiveness over a longer or indefinite limit such that the benefit 
from reduced circumvention was offset by a lower effectiveness? We also 
seek any additional data on effectiveness or acceptance, or any 
relevant studies that NHTSA has not identified in the preamble or the 
PRIA.
    We also seek comment on whether the required durations for the 
visual and audible components of the warning should be identical or 
different (for example, requiring an indefinitely long visual warning 
and an audible warning that is of a relatively long, but limited, 
duration)? Similarly, should the warning durations for the driver and 
passenger differ or be identical? We also recognize that duration is 
not the only warning signal characteristic that might increase 
effectiveness (and affect acceptance); we seek comment on whether NHTSA 
should set minimum performance requirements for other aspects of the 
warning (e.g., volume of audible warning and frequency of visual 
flashing warning and intermittent audible warning) in lieu of or in 
addition to an increase in the warning duration, and the empirical 
support for such a choice. We discuss proposed limits and seek comment 
on certain parameters related to the audible warning below.
2. Requiring an Audio-Visual Change-of-Status Warning
    NHTSA also proposes to require an audio-visual warning whenever the 
driver or front outboard passenger seat belt is unfastened during a 
trip. Although the driver may be aware that the front outboard 
passenger seat belt has been unfastened, we believe a change-of-status 
warning may encourage or remind front outboard passengers to refasten 
their seat belt. We propose an audio-visual warning consisting of a 
continuous or flashing visual warning of icons or text visible to the 
driver and any front outboard passenger and a continuous or 
intermittent audible signal lasting until the seat belt is refastened. 
The warning would be required to activate when the vehicle's ignition 
switch is in the ``on'' or ``start'' position, the vehicle's 
transmission selector is in a forward or reverse gear, and the driver 
and or front outboard passenger seat belt status changes from in use to 
not in use. However, similar to the Euro NCAP protocol requirements, if 
the change-of-status occurs and a front door on the same side of the 
vehicle as the belt triggering the warning is open, the system can 
consider that the start of a new trip. The proposed indefinite duration 
is longer than the minimum 30-second duration proposed for the rear 
seat belt change-of-status warning. We tentatively believe a longer 
duration for the front seat belt warning is justified because it does 
not pose the same potential for driver distraction as it does for the 
rear seat belt warning. Additionally, if the change-of-status is 
finite, this would essentially provide a method of circumventing the 
indefinite startup warning, i.e., an occupant could be buckled at 
startup, but then unbuckle during the trip and only receive a fixed 
duration warning.
    ECE R16 essentially requires the same change-of-status warning 
requirements for the front and rear seats (the duration is generally 
about 30 seconds unless the belt is fastened sooner), so the reader is 
referred to the discussion of the change-of-status warning in 
connection with the rear seat belt warning proposal (Section X.C.2). 
Euro NCAP specifies that the change-of-status warning must essentially 
meet the requirements of the initial warning, but those requirements 
are different for the front and rear seats. Again, for the front seats, 
Euro NCAP specifies that for the initial warning a visual signal shall 
remain active until the seat belt is fastened, and specifies a two-
stage audible signal; the initial audible signal must not exceed 30 
seconds and the final audible signal must be at least 90 seconds.
    We seek comment on the proposed change-of-status warning. What 
types of change-of-status warnings are vehicle manufacturers currently 
using for the front and rear seats (e.g., audio-visual, duration, 
etc.)? NHTSA is also considering, as it is for the start-of-trip 
warning, a limited-duration change-of-status warning. Would a limited-
duration change-of-status warning be preferable? And should it be 
identical to the start-of-trip warning, or is there a reason to require 
different warnings (with respect to any warning signal characteristic, 
but especially duration)? How are vehicle manufacturers currently 
handling change-of-status events that occur when the vehicle is stopped 
or at low vehicle speeds, without a door being opened? Similarly, how 
are change-of-status events handled when passengers exit the vehicle 
without the vehicle being in the park gear?
3. Audible Warning Characteristics
    If the proposed indefinite audible warning were adopted, 
manufacturers would almost certainly design audible warnings that were 
not continuous but instead cycled, in order to avoid the excessive 
annoyance of a fully continuous, long-lasting audible

[[Page 61714]]

warning and to fine-tune annoyance and effectiveness. In light of this, 
NHTSA believes that it is necessary to more fully specify the audible 
warning characteristics than was necessary for a brief audible warning 
to ensure that the warnings have at least a minimum level of 
persistence.
    We therefore propose to define a set of terms objectively 
describing the audible warning: warning cycle, chime frequency, and 
duty cycle:
     A warning cycle for an intermittent audible warning 
consists of period(s) when the warning is active at the chime frequency 
or continuously, and inactive period(s). A warning cycle begins with an 
active period and is 30 seconds in duration.
     Chime frequency means the repetition rate for an 
intermittent audible warning when the warning is active.
     Duty cycle means the total amount of time an intermittent 
audible warning is active during a warning cycle at the chime frequency 
or continuously, divided by the total warning cycle duration (30 
seconds).
    When an audible warning is emitting sound, it may do so 
continuously or intermittently. We believe if the chime frequency of 
the warning is too low, the warning may become less effective. In a 
2009 agency study that focused on analyzing characteristics of optimal 
reminder systems, we found that, among the reminder systems analyzed, 
the one with the highest belt use rate had the longest average single-
cycle duration and the highest maximum sound frequency.\241\ However, 
the agency wishes to provide ample design latitude with respect to the 
chime frequency. In a 2007 agency-funded study on enhanced seat belt 
reminder features, the ``slow chime'' warning evaluated had a 0.83 Hz 
frequency.\242\ We are proposing a minimum frequency of 0.5 Hz. The 
warning will be considered active when the audible warning is emitting 
a continuous sound or a sound at a 0.5 Hz frequency or higher. We seek 
comment on the proposed specification for minimum chime frequency.
---------------------------------------------------------------------------

    \241\ Mark Freedman et al., Effectiveness and Acceptance of 
Enhanced Seat Belt Reminder Systems: Characteristics of Optimal 
Reminder Systems Final Report. DOT HS 811 097.
    \242\ DOT HS 810 848; Lerner, N; Singer, L; Huey, R; Jenness, J; 
``Acceptability and Potential Effectiveness of Enhanced Seat Belt 
Reminders System Features,'' (2007)
---------------------------------------------------------------------------

    Another important characteristic for an indefinite warning is the 
duty cycle. The duty cycle is the ratio of the total time when the 
audible warning is active divided by the total warning cycle time. A 
1.0 or 100-percent duty cycle for a 30-second warning cycle means that 
the warning is active throughout the entire 30 seconds. In order for 
the duty cycle specification to be meaningful, the warning cycle time 
must be specified. We are proposing that the warning cycle be fixed at 
30 seconds. Therefore, because we are proposing that the audio-visual 
warning continue until an unfastened seat belt at an occupied seat is 
buckled, the audible warning will be composed of a continuous series of 
30-second warning cycles that continues until the belt is buckled.
    We have tentatively decided to require a minimum duty cycle of 0.20 
or 20 percent (i.e., 6 seconds for each 30-second warning cycle). We 
have tentatively selected this because we are aware of research data 
that suggests that a 20 percent duty cycle is effective but are not 
aware of data that a lower duty cycle would be sufficiently effective. 
In 2012, IIHS published a study examining the effects of duty cycle and 
duration on seat belt reminder effectiveness and annoyance.\243\ The 
study examined four duty cycle conditions: 100, 50, and 20 percent, and 
a basic reminder (as ratios 1.0, 0.5 and 0.2). The warning cycles were 
consecutive 30 intervals. In the 100 percent duty cycle condition, the 
flashing icon and 1 Hz frequency chime were present for the entire 30-
second reminder cycle. In the 50 percent duty cycle condition, the 
flashing icon and 1 Hz frequency chime were present for the first 15 
seconds of the reminder cycle, and a continuously illuminated icon was 
present for the final 15 seconds. In the 20 percent duty cycle 
condition, the flashing icon and 1 Hz frequency chime were present for 
the first 6 seconds of the reminder cycle followed by a continuously 
illuminated icon for the remaining 24 seconds. In the basic reminder 
system condition, the flashing icon and chime were present for the 
first 6 seconds of the first reminder cycle only, and then icon was 
continuously illuminated for the remainder of the warning. In terms of 
effectiveness, the 20 percent duty cycle reminder was rated no less 
effective than the 100 percent duty cycle reminder.
---------------------------------------------------------------------------

    \243\ Kidd, D.G. (2012). Response of part-time belt users to 
enhanced seat belt reminder systems of different duty cycles and 
duration. Transportation Research Part F, 15, 525-534.
---------------------------------------------------------------------------

    The chime frequency and duty cycle can also be adjusted to optimize 
the warning. As chime frequencies and/or duty cycle increase, 
effectiveness generally (though not necessarily) increases, and 
annoyance generally increases. Given the proposed indefinite warning 
duration for the front seats, vehicle manufacturers would almost 
certainly design warnings with duty cycles of less than 100 percent in 
order to address consumer acceptance issues. For instance, the 2012 
IIHS study found that a decrease in the duty cycle could reduce 
annoyance while not appreciably reducing effectiveness. The enhanced 
reminders, however, were not equally annoying. Forty percent of 
participants in the 1.0 duty cycle reminder condition and 40 percent of 
participants in the 0.5 duty cycle reminder condition agreed or 
strongly agreed that the reminder distracted them while they were 
driving. However, only 25 percent of participants in the 0.2 duty cycle 
reminder condition indicated the reminder distracted them. 
Manufacturers can also balance the duty cycle against the chime 
frequency.
    These proposed specifications differ somewhat from Euro NCAP and 
ECE R16. Rather than directly specifying a duty cycle, Euro NCAP 
specifies that for the front seats the audible signal must not have 
gaps greater than 10 seconds, and that gaps longer than 3 seconds would 
not count toward the warning's total duration. ECE R16 also does not 
count warning gaps longer than 3 seconds toward the required minimum 
warning duration requirement. We are not specifying a limit on the 
maximum duration of audible gaps for the purposes of determining the 
warning's total duration since we are not proposing a minimum warning 
duration requirement. The 10 second limit Euro NCAP specifies, in 
addition to its specification of a 3 second gap limit toward the 
calculation of the warning's total duration, would not be sufficient to 
ensure a 0.20 duty cycle warning (that is supported by the IIHS 
research). For instance, a system with a warning cycle that is 11 
seconds long and a 10 second gap would result in a duty cycle of 0.09 
which would likely not be as effective as a system meeting our proposed 
requirements.
    We seek comment on our proposed method of specifying the audible 
warning duty cycle and the limits proposed.
4. Visual Warning Characteristics
    We are retaining the existing requirements with respect to some 
aspects of the visual warning and modifying them in other respects.
    We are retaining the current requirements that the warning be 
continuous or intermittent (flashing) and must display either the 
identifying symbol or the words (``Fasten Belts'' or ``Fasten Seat 
belts'') specified in table 2 of FMVSS No. 101. We have tentatively 
decided not to specify minimum requirements for the duty cycle or flash

[[Page 61715]]

rates analogous to what we are proposing for the audible warning; we 
tentatively believe that manufacturers will design the visual warning 
features in conjunction with and in a way that complements the audible 
warning characteristics. We have decided to retain the requirement for 
the symbols or text specified in FMVSS No. 101 because these visual 
warning have been in place for decades and we believe that consumers 
are accustomed to them. Removing the requirement may have unintended 
negative effects if drivers and front passengers are not accustomed to 
new visual warnings or do not find the new visual warnings as 
effective. This means that if a manufacturer chose to use a pictogram 
format for the rear seat belt warning, it could include the front seat 
belts in this pictogram, but it would also have to provide the warnings 
specified in FMVSS No. 101, table 2. We believe manufactures are 
already doing this. We seek comment on all of these tentative 
decisions.
    We are also proposing requirements with respect to telltale 
visibility. We propose requiring that if there is a driver's designated 
seating position, the visual warning for the driver's seat belt must be 
visible from the driver's seat and the visual warning for the front 
outboard passenger seat belt must be visible from the driver's seat and 
the front outboard passenger seat. (For the case where there is not a 
driver's designated seating position (which is the case with an ADS-
equipped vehicle without any manual driving controls), see Section 
XII.C.). We are proposing to require that the visual warning be visible 
to both the driver and any front outboard passenger because NHTSA's 
study on front seat belt warning systems suggests that visual warnings 
for front outboard passenger seat belts are more effective when they 
are visible to the passenger as well as the driver.\244\ Euro NCAP 
similarly recommends that the visual warning be visible to the front 
passenger.\245\ We believe it would be practicable for manufacturers to 
comply with this requirement; for example, the warning could be located 
in the center console display (which might be a salient place to 
present visual displays, both because of its location and because it 
may allow larger size icons or text).\246\ Some manufacturers already 
provide a passenger seat belt warning in close proximity to the 
passenger air bag status indicator, which is visible to both the driver 
and front passenger.
---------------------------------------------------------------------------

    \244\ See DOT 2009 Seat Belt Study at 67-68.
    \245\ Section 3.7.5.5.
    \246\ DOT 2009 Seat Belt Study at 67-68.
---------------------------------------------------------------------------

    We have tentatively decided not to specify more detailed criteria 
for the location or visibility of the telltale as, for example, are 
provided in S19.2.2 for the passenger air bag telltale. A visual 
warning for the driver's seat belt has been required since the early 
1970s and we are not aware of any issues with the visibility of that 
telltale, so we tentatively believe this is unnecessary.
5. Other Warning Signal Features and Criteria
    We have tentatively decided not to specify requirements or criteria 
for other aspects of the front outboard seat belt warnings.
    Warning activation criteria. Global and Honda commented that NHTSA 
should consider updates to the driver seat belt reminder requirements 
to include additional trigger thresholds beyond the vehicle ignition 
switch being moved to the ``on'' or ``start'' position. The commenters 
believed advances in vehicle sensor technology enable warnings to be 
provided for a range of conditions, such as when the vehicle speed 
reaches a certain limit, or when the transmission is moved from the 
park position. One commenter suggested that the front and rear warning 
requirements be consistent in this respect.
    Euro NCAP and ECE R16 specify additional trigger requirements above 
and beyond the ignition being engaged and a seat belt not fastened for 
some aspects of the front seat belt warnings. Euro NCAP specifies 
trigger criteria related to factors such as speed, distance traveled, 
and time elapsed for the change-of-status warning, the audible warning 
at the start of a trip, and the final (loud and clear) warning. ECE R16 
specifies, for both the start of trip warning and the change-of-status 
warning, additional activation criteria for the second-level warning 
related to vehicle speed, distance traveled, and time elapsed.
    We have tentatively decided not to specify trigger criteria other 
than the criteria proposed above. The reasons for doing so mirror the 
reasons given in the analogous discussions in the rear seat belt 
warning discussion. See Section X.C.1.b (start-of-trip warning) and 
Section X.C.2 (change-of-status warning).
    Warning duration criteria. Euro NCAP and ECE R16 also specify 
additional duration criteria other than a minimum time and the seat 
belt becoming fastened. Euro NCAP specifies, for the audible warning 
duration (for both the start-of-trip and change-of-status warnings) 
criteria related to vehicle speed, door/belt status, running time, and 
distance traveled.\247\ ECE R16 specifies, for the second-level audio-
visual warning duration for the front seat belts an additional 
criterion related to vehicle speed.\248\ We have tentatively decided 
not to include more complex criteria. The reasons for this mirror the 
reasons given for the rear seat belt change-of-status warning duration 
in Section X.C.2.
---------------------------------------------------------------------------

    \247\ Section 3.4.1.6.
    \248\ Section 8.4.2.4.3 (warning can cease if vehicle is not 
moving forward at least 10 km/h).
---------------------------------------------------------------------------

    Warning circumvention, acknowledgment and deactivation. We have 
tentatively decided not to propose features to harden the system 
against circumvention (such as a sequential logic system which would 
evaluate whether the belt was fastened prior to an occupant sitting in 
the seat or sensors that can determine seat belts fastened behind an 
occupant's back) because such features would increase the cost and 
complexity of the systems. Neither ECE R16 nor Euro NCAP require such 
features.
    We have also tentatively decided not to allow features which would 
permit the driver to acknowledge the warning and cancel it prior to the 
required duration or to deactivate the warning for an entire trip or 
for a specified time period (thus preventing it from activating in the 
first place). ECE R16 allows both short-term and long-term deactivation 
of the audible warning (with a variety of restrictions, such as that it 
be more difficult to effectuate a short-term deactivation than to 
buckle the belt). Euro NCAP does not provide any specifications for 
deactivation or acknowledgement of the warnings for the front seats; it 
only allows acknowledgement of warnings for rear seats, except for 
change-of-status warnings. We seek comment on this. Should a final rule 
incorporate either or both of these features? Would this unacceptably 
impact the effectiveness of the warning and essentially negate its 
indefinite duration? Or could it facilitate acceptance and thus either 
not impact effectiveness or even have a positive impact on 
effectiveness, to the extent it might make it less likely that the 
occupant habitually completely circumvents the system? Or should 
cancelation or deactivation be allowed for the passenger seat belt 
audible warning but not the driver seat belt warning, in order to 
mitigate the potential for false positives (due to cargo on the seat 
that the occupant detection system classifies as a person, etc.)? We 
note that, since we are not proposing hardening requirements, the 
proposal would not preclude designs that do not

[[Page 61716]]

activate a passenger seat belt warning if the seat belt is fastened and 
no one is in the seat. Thus, such nuisance warnings due to cargo could 
be prevented by buckling the seat belt or simply placing the cargo 
somewhere else.
    Should the final rule allow for permanent or short-term 
deactivation of front seat audible warnings when the vehicle is 
traveling below a certain speed? This might allow for situations such 
as someone needing to drive to a mailbox on a road located on private 
property or perhaps driving in a parking lot. Below what speed could 
such a deactivation be implemented without potential loss of benefits? 
Would such an allowance cause confusion and be counterproductive to the 
goal of the proposal?

XII. Other Issues

A. Automatic Belts

    This proposal applies to automatic belts. Automatic belts are belts 
that secure without any action by the occupant. The agency is not aware 
of any currently produced vehicles that would be affected by the 
proposed requirements that have automatic belts. We propose that a 
seating position with an automatic belt would have to meet the same 
seat belt warning requirements that apply to manual belts. We are not 
including provisions in the proposed test procedures specific to 
automatic seat belt systems because we believe the seat belt use 
definitions provide sufficient guidance. We seek comments on this 
issue.

B. Test Procedures

    This NPRM includes procedures for how the agency would test the 
front outboard passenger and rear seat belt warning systems for 
compliance with the proposed requirements.
    We note that ECE R16 (in Annex 18) sets out some limited test 
procedures. With respect to the front passenger belt warning, it sets 
out procedures for testing the warning when the seat belt is unbuckled 
at the onset of a trip and procedures for testing the change-of-status 
warning. For the rear seat belt warning system, it has procedures for 
testing the change-of-status warning. In Europe and other countries 
around the world, compliance with safety standards is based on type 
approval. Type approval is the confirmation that production samples of 
a design will meet specified performance standards. For type approval, 
manufacturers submit product specifications to governmental 
authorities, which then require third party approval testing, 
certification, and a production conformity assessment by an independent 
body. Test procedures in FMVSS, on the other hand, are more extensive 
and detailed, because an FMVSS must be objective, so that manufacturers 
can self-certify that their vehicles are in compliance.
    The proposed test procedures in this NPRM specify that NHTSA could 
test any system under any combination of seat occupancy or seat belt 
use status. The test procedures also specify how the agency would test 
a seat belt warning system with a designated seating position that is 
occupied.
    In order to test a seat belt warning system with a front seating 
position that is occupied, the agency would use either any 
anthropomorphic test device specified in part 572 or a person meeting 
or exceeding the proposed weight and height criteria (at least 46.7 kg 
and 139.7 cm, respectively, corresponding to the 5th percentile adult 
female test dummy specified in part 572). The human beings or test 
dummies used would be seated, the seat belt use and ignition conditions 
would be applied, and the required signals must operate (that is, 
either activate or not activate) accordingly. For example, if the 
agency placed the appropriate test dummies in both front outboard 
seating positions and fastened both outboard seat belts so that the 
seat belts were in use, the front seat belt warning system would not be 
permitted to activate the audible or visual signals under the current 
first compliance option and could only activate the visual signal under 
the current second compliance option.\249\ The test could be conducted 
with the seat and adjustable belt anchorages in any position.
---------------------------------------------------------------------------

    \249\ The first option requires that if the key is in the ``on'' 
or ``start'' position and the seat belt is not in use, the vehicle 
must provide a visual warning for at least 60 seconds, and an 
audible warning that lasts 4 to 8 seconds. Under the second option, 
when the key is turned to the ``on'' or ``start'' position, the 
vehicle must provide a visual warning for 4 to 8 seconds (regardless 
of whether the driver seat belt is fastened) and an audible warning 
lasting 4 to 8 seconds if the driver seat belt is not in use.
---------------------------------------------------------------------------

    For rear warning systems that utilize occupant detection (either 
negative-only or full-status systems), the agency would use either a 
person or any anthropomorphic test device specified in part 572 that 
meets the proposed weight and height criteria (at least 21 kg and 114 
cm, respectively).\250\ The agency would perform the test with the seat 
in any position, the seat back in the manufacturer's nominal design 
riding position, and any adjustable anchorages in any position.
---------------------------------------------------------------------------

    \250\ For anthropomorphic test devices, this would include the 
50th percentile male, 5th percentile female, and the 6-year-old and 
10-year-old child dummies.
---------------------------------------------------------------------------

    We seek comment on all aspects of the test procedures. We also seek 
comment on whether the R16 Annex 18 test procedures affect how the 
requirements in R16 should be interpreted, and whether any deviations 
between the proposed test procedures and the Annex 18 test procedures 
are undesirable. We also seek comment on whether the proposed 
procedures are sufficiently detailed and objective.

C. Considerations for Automated Driving Systems

    The ANPRM did not address considerations related to automated 
driving systems (ADSs).
Comments
    A commenter recommended avoiding any additional references to the 
``driver'' in FMVSS No. 208 to avoid introducing further barriers to 
the deployment of automated driving systems.
Agency Response
    NHTSA is actively addressing how the FMVSS might be revised to take 
vehicles with different types of ADSs into account. On March 30, 2022, 
NHTSA published a final rule updating the occupant protection standards 
(200-series FMVSS) to account for ADS-equipped vehicles, particularly 
those without driving controls.\251\ The final rule amended the 200-
series FMVSS to account for future vehicles that do not have the 
traditional manual controls associated with a human driver because they 
are equipped with ADSs.
---------------------------------------------------------------------------

    \251\ 87 FR 18560 (Mar. 30, 2022).
---------------------------------------------------------------------------

    One aspect of this NPRM is a requirement specifically tailored to 
an ADS-equipped vehicle without a driver DSP. For the amendment to the 
driver's seat belt warning, we are proposing that the front passenger 
warning apply to ``any'' front outboard passenger. The addition of the 
term ``any'' makes it clear that, in some vehicles, there may be more 
than one front outboard passenger seating position. This would be the 
situation of an ADS-equipped vehicle that has no manually operated 
driving controls. The agency views this as a means for maintaining the 
same level of occupant protection in ADS-equipped vehicles that exists 
in conventional vehicles, i.e., both will be required to have seat belt 
warnings in both outboard seating positions. We note that in a dual 
mode vehicle,\252\ the

[[Page 61717]]

left front seat is still by definition a driver's seat, regardless of 
the operational status of the vehicle, so a provision to just have a 
warning for the driver and right outboard passenger would be sufficient 
to assure that all front seat occupants receive a warning.
---------------------------------------------------------------------------

    \252\ An [ADS-Equipped] Dual-Mode Vehicle is defined as ``[a] 
type of ADS-equipped vehicle designed for both driverless operation 
and operation by a conventional driver for complete trips.'' SAE 
J3016_201806 Taxonomy and Definitions for Terms Related to Driving 
Automation Systems for On-Road Motor Vehicles.
---------------------------------------------------------------------------

    We are also proposing that if there are multiple front outboard 
passenger seats in an ADS-equipped vehicle without manual driving 
controls, then both front outboard seat belt warnings and change-of-
status warnings must be visible to both front outboard passengers. The 
rationale for this is as follows. Although an ADS-equipped vehicle 
without manually operated controls by definition does not have a 
driver, it is reasonable to assume that one of the front outboard 
passengers may be performing the management role for the duration of a 
trip, such as might be the case of a parent in a vehicle with children 
under their care. In such a situation, the manager of the trip may be 
seated in either front outboard seat. Thus, to be most beneficial, the 
visual warning must be seen by an occupant choosing to sit in either 
front outboard seat. Additionally, if the agency restricted the warning 
visibility to just the right outboard passenger and not ``any'' 
outboard passenger, in an ADS-equipped vehicle with no driving controls 
and a lone vehicle occupant in the left front seat, that occupant would 
not receive a seat belt use warning.
    The 2022 ADS final rule also addressed situations where an ADS-
equipped vehicle without manual driving controls has one or no outboard 
seats in the front row (e.g., an ADS-equipped vehicle with only two 
seats in the front row, one or both of which would be classified as 
inboard passenger seating positions under 571.3) and requires seat belt 
warnings for certain inboard seats in such vehicles. We are proposing 
that these front inboard passenger seats have the same seat belt 
warnings as front outboard seats.
    The agency acknowledges that the proposal does not address the 
influence of ADS-equipped vehicles on the visibility of the rear seat 
belt warning. As proposed, the rear seat belt warning is only required 
to be visible from the driver's seat. As previously discussed, there 
may be no driver's DSP in an ADS-equipped vehicle. Thus, no vehicle 
occupant will be required to see the rear seat belt warning. NHTSA 
acknowledges the inadequacy of this situation and we believe there are 
many potential solutions. For example, it could be required that for a 
vehicle without manually operated driving controls, any front seat 
occupant receive the rear seat belt warning. Another approach would be 
to require that in such vehicles, all seating positions be apprised of 
the seat belt use in all other DSPs in the vehicle. The agency has 
determined that it is not prepared to propose a solution for the 
visibility of rear seat belt warnings for ADS-equipped vehicles and 
that it is beyond the scope of this proposed rule. As we stated in the 
March 30, 2022 final rule, the agency plans future agency work related 
to telltales and indicators for ADS-equipped vehicles.

XIII. Regulatory Alternatives

    NHTSA has considered alternatives to the proposal. In the preceding 
sections of this document, we have discussed various alternatives for 
different aspects of the proposed requirements. In this section we 
address five major alternatives that we considered: ECE R16 and Euro 
NCAP; occupant detection and enhanced warning signals for the rear seat 
belt warning; non-regulatory alternatives; requiring a warning for the 
front center seat; and requiring an audio-visual seat belt warning for 
the front outboard seating positions with a duration not less than 90 
seconds. For three of these alternatives (rear-seat occupant detection, 
front center seat, and 90-second front warning), we also quantified the 
costs and benefits (see Section XIV).

A. ECE R16 and Euro NCAP

    The ANPRM sought comment on the extent to which any requirements 
should be based upon or differ from other regulatory requirements (such 
as ECE requirements) or consumer information programs such as Euro 
NCAP.\253\ As discussed in more detail in the regulatory analyses 
section below, Executive Order 13609 provides that International 
regulatory cooperation can reduce, eliminate, or prevent unnecessary 
differences in regulatory requirements. Similarly, Sec.  24211 of the 
Infrastructure, Investment, and Jobs Act \254\ instructs DOT to 
harmonize the FMVSS with global regulations to the maximum extent 
practicable (for example, to the extent that harmonization would be 
consistent with the Safety Act).
---------------------------------------------------------------------------

    \253\ The discussion in this preamble focuses on Euro NCAP and 
R16. NCAP programs in other regions are largely similar to Euro NCAP 
or R16, so our analysis of these requirements will adequately cover 
the requirements of the NCAP programs in other regions.
    \254\ H.R. 3684 (117th Congress) (2021).
---------------------------------------------------------------------------

Comments \255\
---------------------------------------------------------------------------

    \255\ The ANPRM sought comment on this in the context of various 
aspects of the rear seat belt warning, and this is what the comments 
likely concerned, but the discussion in the agency response below 
also includes the front seats.
---------------------------------------------------------------------------

    Several commenters recommended harmonizing with R16.\256\ Two 
commenters stated that almost all automakers have already developed 
systems to conform to the R16 requirements, and that disharmonization 
would increase costs without any benefits. Two commenters said that 
harmonization would accelerate introduction of seat belt reminders. A 
commenter said that R16 represents a ``sweet spot'' between safety 
benefits, consumer acceptance, harmonization, and compliance costs. The 
commenter also said that the benefits from harmonization can be 
substantial, such as flexibility to innovate, cost minimization, and 
efficiency of global research, development, and production processes; a 
non-harmonized approach could also necessitate system redesign for the 
United States market.
---------------------------------------------------------------------------

    \256\ Some comments specifically identified version R16-07. As 
noted earlier, the ECE has subsequently revised that regulation. The 
current version is Revision 10. We assume commenters favoring 
harmonization intended that we harmonize with the most current 
version of R16.
---------------------------------------------------------------------------

    Some commenters recommended harmonizing with NCAP programs in other 
regions, such as Euro NCAP. For example, a commenter supported 
harmonization with Euro NCAP; another supported harmonization with Euro 
NCAP (or, if not that, then with R16), and a third commenter suggested 
using other NCAP programs as a model when empirical data is lacking. A 
commenter recommended harmonization with Euro NCAP and IIHS's 
assessment protocol.
    A few commenters, while acknowledging that harmonization is 
generally desirable, commented that the proposed rule should not 
harmonize at the expense of safety/effectiveness. Commenters said that 
the requirements should be evidence-based.
Agency Response
    In developing this proposal, our intent was to harmonize with ECE 
R16 and Euro NCAP as much as possible but deviate where we believed it 
was justified with respect to the Safety Act criteria (need for safety, 
objectivity, practicability). The tentative reasons for following or 
deviating in any of these respects are explained in detail in the 
relevant section of the preamble. In general, we believe that although 
the proposal deviates from R16 in some

[[Page 61718]]

ways, the two are not incompatible, so that it is possible to design a 
rear reminder system that complies with the proposed requirements and 
is compatible with R16.
    On December 2021, IIHS released its Seat Belt Reminder System Test 
and Rating protocol.\257\ It sets out general requirements for the seat 
belt reminder visual and audible signals for front outboard and rear 
seating positions. It does not put much emphasis on the visual warning 
for front-outboard seating positions other than specifying that a 
visual signal needs to be displayed in the instrument panel, overhead 
panel, or center console, indicating an unfastened belt. On the other 
hand, for the audible warning there are requirements for when it must 
begin if the seat belt is unfastened at ignition and for change-of-
status, and when it can cease (when the seat belt is unfastened, 
vehicle is no longer in motion, or seat is no longer occupied). It also 
has sound pressure level and frequency requirements for the audible 
warning.
---------------------------------------------------------------------------

    \257\ https://www.iihs.org/media/f15e5be9-ac62-4ea6-a88d-7511105bfff5/H3hGKQ/Ratings/Protocols/current/Seat%20Belt%20Reminder%20Test%20Protocol.pdf.
---------------------------------------------------------------------------

    For the rear seats, it specifies that the visual signal must 
activate within 10 seconds of the ignition being turned on, that the 
signal must indicate whether the seat belt at each rear seating 
position is fastened or unfastened, and that it must last at least 60 
seconds. It does not require a visual signal if the seat belts at all 
occupied rear seats are fastened or if no rear occupants are present. 
It allows the visual signal to be cancelled by the driver. For a seat 
belt change-of-status in the rear seats when the vehicle is in motion, 
it requires an audible and visual signal that lasts at least 30 
seconds. It further specifies that the audible and visual signal can 
stop when seat belts at the occupied rear seats are fastened, the 
vehicle is no longer in motion, or the seats are no longer occupied.
    For the front seats, under the IIHS ratings protocol, the primary 
audible reminder signal for the front outboard seats must be at least 
90 seconds in total duration in order to obtain an ``acceptable'' or 
``good'' rating.
    Unlike Euro NCAP the IIHS rating system provides ratings instead of 
points (poor, marginal, acceptable, good). For instance, if the front-
passenger seat has an audible signal that lasts less than 8 seconds it 
would be given a ``Poor'' rating. For a ``Good'' rating'' both the 
driver and front-passenger belt reminder must have an audible signal 
that lasts at least 90 seconds and meet the rest of the belt reminder 
system requirements (essentially meet the requirements for an 
``Acceptable'' rating) and meet the requirements set forth for the rear 
seat belt reminder system. Accordingly, a vehicle cannot receive a 
``Good'' rating without having a rear seat belt reminder system, and a 
rear seat belt reminder system is not required for all the other 
ratings. It does not specify occupancy criteria. We do not believe our 
requirements impede meeting the requirements of the IIHS protocol.

B. Occupant Detection and Enhanced Warning Signals for the Rear Seat 
Belt Warning

    Rear seat warning systems that employ occupant detection have 
potential advantages over systems without it. With occupant detection, 
a warning system can provide more informative warnings. The system can 
determine whether any seats are occupied by an unbelted occupant, as 
opposed to simply notifying the driver which belts, if any, are 
fastened. Such systems are also better able to provide enhanced 
warnings. Enhanced warnings refer (for the purposes of this document) 
to warnings that are relatively longer-lasting or have an audible 
component. Having an audible or longer-duration visual warning activate 
for an unoccupied seat could be a nuisance for the driver and might 
either desensitize the occupants to the warning signal or lead them to 
circumvent or defeat the system. Enhanced warnings therefore generally 
need to work in conjunction with an occupant detection system.
    In the ANPRM we observed, however, that occupant detection for the 
rear seats may present technical or cost challenges. Rear seats are 
used in ways that can complicate occupant detection. Rear seats may 
frequently be used to transport cargo such as groceries, pets, and 
other heavy objects that could be mistaken for an occupant. In 
addition, rear seats may be less well-defined than front seats, which 
could impede accurate detection. For example, it may be technically 
challenging for an occupant detection system to recognize a large 
occupant spanning multiple seating positions as a single occupant 
rather than two occupants. This could lead to false warnings, which can 
lead occupants to disregard or attempt to circumvent the system. 
Occupant detection would also be more expensive. While approximately 
46.9% of MY 2022 projected vehicle sales in the United Sates have rear 
seat belt warning systems, only about 7% are equipped with occupant 
detection.
    Occupant detection is optional but not required by both ECE R16 and 
Euro NCAP. Accordingly, neither Euro NCAP nor ECE R16 require an 
audible warning on vehicle start-up for the rear seats. Euro NCAP 
specifies that, if there is no occupant detection, only a 60-second 
visual signal is needed for the rear warning in order to earn bonus 
points, and R16 requires a 60-second visual signal. For systems with 
occupant detection in all rear seats, Euro NCAP specifies that the 
visual signal does not need to indicate the number of seat belts in use 
or not in use, but the signal must remain as long as the seat belts 
remain unfastened on any of the occupied rear seats. Neither R16 nor 
Euro NCAP require a visual signal if the system can determine there are 
no occupants in the rear.
    The ANPRM sought comment on whether NHTSA should propose rear seat 
belt warning system requirements that would necessitate occupant 
detection or enhanced warning signals.
Comments
    Many commenters recommended requiring occupant detection in the 
rear seats. Other commenters argued that occupant detection would 
reduce false signals, and some argued that occupant detection was 
feasible and already available in numerous vehicle models. A commenter 
stated that NHTSA had provided no literature review of available 
systems and their capabilities, and that NCAP programs throughout the 
world had concluded that these systems are feasible and important to 
advancing safety. Two commenter said that some of the technological 
challenges NHTSA identified in the ANPRM have already been addressed in 
systems developed for the right front passenger seat. A commenter also 
noted that various NCAP programs award points for occupant detection. 
Another commenter said that the residual technical challenges appear to 
be mostly associated with accommodating certain child restraint 
systems. The commenter believed that occupant detection with the option 
of temporary driver override for the duration of an individual trip is 
a reasonable approach that balances notification with recognition that 
seats may be occupied by objects other than unrestrained human 
occupants. Commenters also said that occupant detection systems are 
cost-efficient, with a number of systems costing less than $10.
    On the other hand, several commenters opposed requiring occupant 
detection. Commenters suggested harmonizing with ECE R16, which does 
not require occupant

[[Page 61719]]

detection. Some commenters brought up the technological and use 
challenges. For example, a commenter stated that it is difficult to 
distinguish actual rear occupants from other rear objects because 
consumers tend to use rear seats in a wider variety of conditions 
(e.g., child restraints, pets, groceries, and various types of cargo); 
its experience shows that occupant detection in rear seats leads to 
false alarms and reduced consumer acceptance. Several commenters raised 
concerns about cost. One commenter believed that the cost of such 
systems would not justify any additional benefits. Another commenter 
believed that there were insufficient data available to demonstrate 
that occupant detection would actually increase system effectiveness 
because without occupant detection the driver knows how many occupants 
are in the vehicle. On the other hand, a commenter said that costs are 
not prohibitive; the commenter also stated that rear seat occupant 
detection systems are available that can take into consideration the 
specific challenges of the rear seat compared to a front seat, 
including robust sensors to help avoid false positive warnings. At the 
same time, commenters requested that any requirements not prohibit 
innovation and provide manufacturers with flexibility. One commenter 
opposed requiring occupant detection on buses because such systems 
would be complicated (e.g., the number of seats and seating 
configurations, challenges with LATCH). It also stated that it is 
unaware of any occupant detection systems currently available for 
buses, so all rear passenger seats currently in use will require 
significant development efforts.
    As noted earlier,\258\ several commenters favored requiring an 
audio-visual warning at the start of the trip. A commenter also 
supported requiring the most effective warnings.
---------------------------------------------------------------------------

    \258\ See Section X.C.1.a, Visual Warning at Start of Trip with 
Three Compliance Options.
---------------------------------------------------------------------------

    On the other hand, commenters argued against requiring enhanced 
warnings. A commenter recommended requiring only a visual warning on 
start-up to avoid false alarms and consumer acceptance issues because 
occupant detection is currently not affordable. Another commenter also 
stated that consumer acceptance of enhanced warning systems in the 
United States is not well understood. Commenters recommended following 
R16 with respect to enhanced warnings, because it strikes an 
appropriate balance of benefits, acceptance, harmonization, and costs. 
Two commenters suggested that NHTSA instead consider updating NCAP to 
include enhanced warnings. A commenter said that the reminder system 
should use existing audio/visual warning patterns because the driving 
public likely would be able to understand those more easily.
Agency Response
    We have tentatively decided not to require occupant detection in 
the rear seats because we tentatively believe that occupant detection 
continues to present technical challenges. While it can reduce false 
warnings for unoccupied seats it can also result in false warnings, due 
to the limitations of the sensors and different use scenarios in the 
rear seats. We acknowledge that most of the components necessary to 
meet the proposed minimum performance requirements for a system with 
occupant detection are readily available, and that a small portion of 
the total U.S. vehicle projected sales, based on the MY2022 NCAP data, 
are equipped with rear SBWS with occupant detection. However, these 
potential issues surrounding the implementation of occupant detection 
could reduce the effectiveness and/or acceptance of these systems and 
thus we tentatively decided against requiring occupant detection.
    Occupant detection would be cost-beneficial only if rear seat belt 
use increased substantially more than we estimate that it would for a 
warning system without occupant detection. Our teardown analysis 
indicates that occupant detection components cost $39.75 per vehicle, 
which, added to the $19.59 per vehicle cost of the buckle sensor, 
results in a combined warning system cost of $59.33 per vehicle (2020 
$). We estimate that the total new fleet cost of a rear seat belt 
warning system with occupant detection would be about $758 million 
(2020 $). As explained in more detail in Section XIV, Overview of Costs 
and Benefits, and in the PRIA, in order for benefits and costs to be 
equal for this regulatory option, seat belt use for rear seat occupants 
11 years and older would need to increase by approximately 9.4 percent 
when discounted at 3 percent and 11.6 percent when discounted at seven 
percent. A 9 to 12 percent increase in seat belt use is about 2 to 3 
times greater than that estimated for the proposed SBWS requirement. 
While we would expect some possible increase in seat belt use from that 
specific functionality, it is doubtful that it would double or triple 
the increase in seat belt use estimated for SBWS without occupant 
detection. Therefore, we do not expect this regulatory alternative to 
be cost-effective or net beneficial.
    This tentative decision is based on current information on factors 
such as the needed increase in seat belt use for this regulatory 
alternative to have positive net benefits. This proposal does not 
preclude manufacturers from choosing to use occupant detection and 
includes compliance options that involve the use of occupant detection. 
This harmonizes with R16 and Euro NCAP. Vehicle manufacturers may in 
the future implement rear seat occupant detection technology for other 
functions (such as advanced occupant restraint functions or warnings 
for unattended children in the rear seating positions after the vehicle 
motor is turned off), which would relieve some of the cost burden and 
facilitate the integration of occupant detection technology for rear 
seat belt warning systems. Because we are not requiring occupant 
detection, we are therefore also not requiring enhanced warnings (such 
as an audible warning on vehicle start-up) for the rear seat belt 
reminder. The proposal, however, gives manufacturers the flexibility to 
innovate and optimize warning signal characteristics, including 
providing enhanced warnings. We seek comment on these issues.

C. Non-Regulatory Alternatives

    The ANPRM sought comment on whether NHTSA should consider non-
regulatory approaches. It identified two potential non-regulatory 
approaches: awarding NCAP bonus points and voluntary guidelines.
Comments
    Some commenters supported including rear seat belt reminders in 
NCAP in addition to, but not in lieu of, a regulatory requirement in 
order to accelerate adoption of advanced systems. Two commenters also 
believed that inclusion in NCAP could encourage adoption. One commenter 
was opposed to voluntary guidelines. The commenter said that inclusion 
of occupant detection in NCAP would be the most appropriate way to 
incentivize such systems and familiarize industry with their 
implementation.
Agency Response
    In light of the MAP-21 mandate and our tentative conclusion that 
the proposed requirements would meet the section 30111 criteria, we 
have decided to issue this proposal, and not pursue non-regulatory 
alternatives. However, we would like to note that on March 9, 2022, 
NHTSA published an RFC notice announcing its current and future plans

[[Page 61720]]

for updating NCAP.\259\ The RFC notice included a section on seat belt 
interlocks that requested comment on whether NCAP should consider 
credit for enhanced seat belt reminder systems and whether NCAP should 
include a seat belt interlock assessment and, if so, what it would 
consist of (e.g., interlock types, what seats would be covered, etc.). 
The notice requested data on both topics. Our preliminary review of the 
comments about whether NCAP should consider credit for enhanced seat 
belt reminders found that the majority of commenters were in support of 
such an initiative. A commenter stated that, rather than considering 
credit for enhanced seat belt reminders, NHTSA should regulate more 
persistent reminders as allowed under MAP-21.
---------------------------------------------------------------------------

    \259\ 87 FR 13452 (Mar. 9, 2022).
---------------------------------------------------------------------------

D. Requiring a Warning System for the Front Center Seat

    The agency also considered requiring a seat belt warning system for 
the front center seating position but is not proposing doing so for a 
few reasons.
    First, there is low occupancy for the front center seat. According 
to 2013 FARS and GES data, only 0.4 percent of the occupants of 
passenger cars and light trucks with a GVWR of 10,000 lb or less 
involved in fatal or injury-only crashes were seated in the front 
center seating position. This is due to the rarity of front center 
seats in the modern vehicle fleet, not because this position is safer. 
More specifically, 62 occupants of these vehicles seated in the front 
center seat were killed. Of those fatalities, 79 percent (49 occupants) 
were unrestrained. In addition, there were 8,000 occupants of these 
vehicles that were injured while seated in the front center seat. Of 
those front center seat occupants injured, approximately 8.2 percent 
(656 occupants) were unrestrained.\260\
---------------------------------------------------------------------------

    \260\ See Traffic Safety Facts 2013, NHTSA, DOT HS 812 139 
(2015), Tables 87-88. Only light truck occupant injuries are 
reported. The number of passenger car occupants injured was not 
reported because it was less than 500.
---------------------------------------------------------------------------

    Next, a system for the front center seat without occupant detection 
would likely not be effective. Without occupant detection, a belt 
reminder system for the front center seat would be limited to providing 
a positive-only visual signal (for the reasons discussed regarding the 
front and rear seats and occupant detection). We believe that such a 
signal would not be likely to result in meaningful safety benefits for 
the front center seat. Because it would be only a visible and not an 
audible warning, it would likely not provide the occupant in the front 
center seat much incentive to fasten the seat belt or provide the 
driver an additional incentive to request the front center passenger to 
fasten the seat belt.
    Finally, a system with occupant detection would not be cost-
effective or net-beneficial. When discounted at three and seven 
percent, the cost per ELS is approximately $88.9 million and $110.0 
million, respectively and the net benefits are negative for this 
regulatory alternative. Because the cost per ELS is higher than the 
comprehensive cost of a fatality and the net benefits are negative, 
this regulatory alternative is not cost-effective or net-beneficial.

E. Requiring a 90 Second Duration Seat Belt Warning System for the 
Front Outboard Seating Positions

    As explained earlier (see Section XI.C.1), NHTSA considered a range 
of alternative warning durations for the front outboard seat belt 
warning. NHTSA quantified the costs and benefits for one of these 
alternate durations (90 seconds). NHTSA selected the 90 second duration 
length as an alternative because this is the most common audible 
warning duration for the front outboard seats, based on our NCAP data. 
About 92.4 percent of the new vehicle fleet is already equipped with an 
audible seat belt warning with a duration of 90 seconds or greater. 
Therefore, a requirement for a minimum of 90 second duration audible 
warning would only affect 7.6 percent of the new vehicle fleet. The 
benefit and cost analysis was conducted in a similar manner as that for 
the indefinite duration seat belt warning described in Section XIV. Our 
analysis found that a requirement for a 90-second audible warning would 
save 7 equivalent lives with no change in the estimated cost. These 
benefits are significantly lower than those for the proposed warning 
that remains on until the seat belt is buckled.
    We seek comment on these issues.

XIV. Overview of Benefits and Costs

    In this section, we briefly present our estimates of the benefits 
and costs of the proposed rear and front seat belt warning 
requirements, as well as three of the major regulatory alternatives we 
considered. For a more detailed discussion, please refer to the 
Preliminary Regulatory Impact Analysis (PRIA) in the docket for this 
rulemaking. NHTSA seeks comment on its methodology, data sources, and 
estimates.

A. Proposed Requirements

    NHTSA quantified the benefits and costs of the proposed 
requirements. In this section we present a summary of these estimates 
for the rear seat belt warning system, front outboard seat belt warning 
system, and then the combined costs and benefits for both proposals.
1. Rear Seat Belt Warning System
    The ANPRM sought comment on the potential effectiveness, benefits, 
and costs of a rear seat belt warning.
Comments
    NHTSA received several comments on the potential target population. 
For example, a commenter said that approximately 900 second row 
unrestrained occupants are killed and another 19,000 are injured each 
year, and a portion of this target population would likely have 
injuries mitigated or eliminated through the use of rear seat belt 
warning systems. Another commenter brought up the increasing number of 
rear seat passengers,\261\ including the rise of rideshare 
vehicles.\262\ Two \263\ commenters \264\ also stated that studies have 
found rear seat passengers in rideshare or taxis (for hire vehicles) 
are less likely to buckle up than those in privately owned (not for 
hire) vehicles, and one of the commenters noted that children usually 
sit in the back row, and they may unfasten their seat belt out of 
boredom during a trip. A commenter also said that restraint non-use 
exceeds the national average (47%) in the population of occupants 
starting at age 8-12, and the unrestrained percentage for younger 
occupants is 36% for 4-7 year olds and 22% for occupants less than 4 
years old.
---------------------------------------------------------------------------

    \261\ Citing Li, R., Pickrell, T.M. (2019, February). Occupant 
restraint use in 2017: Results from the NOPUS controlled 
intersection study (Report No. DOT HS 812 594). Washington, DC: 
National Highway Traffic Safety Administration, at: https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/812594.pdf.
    \262\ Citing Aarian Marshall, A Third of Americans Use Ride-
Hail. Uber and Lyft Need More, Wired, Jan. 8, 2019, https://www.wired.com/story/uber-lyft-ride-hail-stats-pew-research/ (last 
accessed Nov. 26, 2019).
    \263\ Citing Jessica Jermakian & Rebecca Weast, Passenger use of 
and attitudes toward rear seat belts. J. Safety Research 66, p. 113-
119, Feb. 2018, https://doi.org/10.1016/j.jsr.2017.12.006 (last 
accessed Nov. 26, 2019); Kenneth Nemire, Seat belt use by adult rear 
seat passengers in private passenger, taxi, and rideshare vehicles, 
Proceedings of the Human Factors and Ergonomics Society Annual 
Meeting, Oct. 20, 2017, https://doi.org/10.1177/1541931213601896 
(last accessed Nov. 26, 2019).
    \264\ Citing Rear Seat Belt Use: Little Change in Four Years, 
Much More To Do, GHSA, (Nov., 2019), https://www.ghsa.org/resources/RearBeltReport19.
---------------------------------------------------------------------------

    Several commenters noted a relative lack of data regarding the 
effectiveness of rear seat belt warnings. A commenter stated that the 
first vehicles with an advanced rear seat belt reminder system

[[Page 61721]]

only entered the Japanese and EU markets in recent years, and there are 
not yet any field data available on effectiveness.
    However, a few commenters did provide rough effectiveness 
estimates. One commenter estimated that it was likely similar to front 
seat effectiveness (3-4%). Two other commenters pointed to a 2012 SAE 
paper that compared the effect of various visual and audible warnings 
on rear belt use based on a series of experiments.\265\ One of the 
commenters said that its research has found that seat belt warning 
systems with persistent audible tones lasting at least 90 seconds 
increase the seat belt use of drivers who do not routinely use a seat 
belt by 34%. The commenter also referenced a Volvo survey of Volvo 
owners in Sweden and Italy in 2005 showing that a rear belt warning 
system had an effectiveness of approximately 50%.
---------------------------------------------------------------------------

    \265\ M. Akamatsu, H. Hashimoto and S. Shimaoka, ``Assessment 
Method of Effectiveness of Passenger Seat Belt Warning,'' in SAE 
International 2012-01-0050, 2012. This study is discussed in the 
PRIA (Section 2.3).
---------------------------------------------------------------------------

    Several commenters commented generally that a rear belt reminder 
would be effective while not providing specific effectiveness 
estimates. A commenter agreed with NHTSA that the proportion of 
occupants who actively seek to avoid restraint use is small compared to 
the proportion of part-time nonusers who would likely be amenable to 
warnings. Another commenter similarly stated that many consumers do not 
prioritize rear belt use but rather consider it unnecessary (for short 
trips in particular), forget to buckle up, or perceive no deterrent 
threat from traffic enforcement, and enforcement of seat belt laws is 
more challenging for the back seat due to more difficult visibility. A 
commenter said that there is extensive evidence of the effectiveness of 
front seat belt reminders and there is no reason to believe that rear 
seat belt reminder effectiveness would significantly differ. Commenters 
noted the NHTSA research on seat belt warnings discussed in Section V, 
showing a generally positive increase in use rates. Commenters referred 
to an IIHS survey showing that, of 1,172 respondents who had ridden in 
the back seat during the preceding six months, 75% said they would be 
more likely to wear the rear seat belt if someone in the car reminded 
them, 62% would if there was an audible belt reminder, and 50% would if 
there was a visual belt reminder.\266\
---------------------------------------------------------------------------

    \266\ Citing Highway Loss Data Inst., Ins. Inst. for Highway 
Safety, Unbelted: Adults Admit They Often Skip Belts in Rear Seat, 
52 Status Rep. 1, 3 (Aug. 3, 2017), available at https://www.iihs.org/api/datastoredocument/status-report/pdf/52/5 (last 
accessed Nov. 26, 2019).
---------------------------------------------------------------------------

    With respect to costs, a commenter said that seat belt reminder 
systems require a relatively small investment, and low-cost 2-D or 
digital cameras (which are cheaper than seat sensors) could be used to 
detect a rear seat passenger. Two commenters said that the cost will 
decrease further if rear seat belt reminder systems are required in all 
vehicles. A commenter said that for passenger cars already equipped 
with rear seat buckle monitoring (13% in US for MY 2019; almost 100% of 
new vehicle models in the EU market, legally required in EU for new 
types from September 2019 onwards), the additional costs for the 
occupant detection technology to cover the second row seating positions 
are in the low two-digit range. The commenter also stated that among 
vehicles available in the EU with advanced rear seat SBR systems, a 
couple are vehicle models that belong to the high-volume, cost-
sensitive vehicle segments (small/compact cars), showing that the 
additional costs for the rear seat occupant detection are not 
prohibitive. The commenter said that the occupant detection sensors for 
a seat belt warning system are available at lower costs than occupant 
classification (e.g., for front air bags) sensors.
Agency Response
    Based on FARS and NASS-CDS data from 2011 to 2015, on average 1,002 
unrestrained rear seat occupants were killed in crashes and 7,820 were 
injured.\267\ After adjusting these to account for future decreases in 
fatalities and injuries projected to occur in the absence of the 
proposed requirements due to the introduction of other mandatory safety 
technologies (e.g., electronic stability control), there were, on 
average, 475 fatalities and 7,036 injuries to unrestrained rear seat 
occupants each year. This is the overall target population--the annual 
deaths and injuries that the proposed requirements are aimed at 
reducing.
---------------------------------------------------------------------------

    \267\ See PRIA, Appendix D.
---------------------------------------------------------------------------

    We estimated the benefits we expect to result from the proposed 
rear seat belt warning requirements. The benefits are the fatalities 
and injuries that we estimate would be prevented by the proposed 
requirements. The benefits depend, principally, on the effectiveness of 
seat belts in preventing deaths and injuries and the expected increase 
in seat belt use due to the proposed rear seat belt warning system 
requirements. Seat belt effectiveness for rear seat occupants is 55 
percent for passenger cars and 74 percent for light trucks and 
vans.\268\
---------------------------------------------------------------------------

    \268\ See PRIA, Table 29.
---------------------------------------------------------------------------

    NHTSA believes that the proposed minimum required warning signal 
characteristics would be effective at informing the driver of the use 
status of the rear seat belts and facilitating the driver to request 
that a rear passenger fasten an unfastened belt. A seat belt warning 
system can increase rear seat belt use in two ways: it can remind an 
occupant to fasten their belt, and it can inform the driver that a 
passenger is unbuckled, so that the driver can request the occupant to 
fasten their belt.\269\ Without a rear seat belt warning, the driver 
must turn around to ascertain whether a rear seat occupant is using a 
seat belt (or ask the occupant); in some vehicles, belt use may not be 
evident to the driver, even if he or she turned around, due to line-of-
sight limitations. As noted above, in NHTSA's 2015 survey, 65% of 
drivers of vehicles equipped with rear seat belt reminders reported 
that the rear seat belt reminder made it easier to encourage the rear 
seat passengers to buckle up.\270\ Also, as noted earlier, part-time 
users--the predominant nonuser group--are amenable to seat belt 
warnings. In addition, children, who might be particularly compliant to 
driver requests, are proportionally much more likely to be rear seat 
passengers than are adults.\271\
---------------------------------------------------------------------------

    \269\ Motoyuki Akamatsu et al., Assessment Method of 
Effectiveness of Passenger Seat Belt Reminder. 2012-01-0050, SAE 
International (2012).
    \270\ Survey of Principal Drivers of Vehicles with a Rear Seat 
Belt Reminder System at 47.
---------------------------------------------------------------------------

    We believe that any of the three compliance options would be 
effective at doing this. While some provide more information than 
others, and some would require the driver to fill in some informational 
gaps, even the most basic system (positive-only) would inform the 
driver about which belts are fastened; the driver would readily be able 
to determine whether there were any unbelted occupants. We also believe 
that the 60-second visual warning would be effective. NHTSA could have 
proposed a more intrusive warning signal, such as an audible warning 
and/or a longer-duration visual warning. However, because such warnings 
necessitate occupant detection and we have tentatively decided not to 
require occupant detection, we have also tentatively decided not to 
propose more aggressive warnings.
    NHTSA estimated the effectiveness of the proposed rear seat belt 
warnings. Available research regarding seat belt use indicates that 
seat belt warning

[[Page 61722]]

systems are effective at increasing seat belt use; however, estimates 
of the amount of increased belt usage that can be attributed to warning 
systems vary. In arriving at our estimates of increased seat belt 
usage, we examined research conducted by NHTSA and others, as well as 
information submitted in response to the request for comments. For rear 
seat passengers eleven years old and older, we used a ``low'' estimate 
of 3.4 percentage points, and a ``high'' estimate of 5.1 percentage 
points.\272\ For rear seat passengers from six to eleven years old, we 
used a low estimate of 0.27 percentage points and a high estimate of 
0.41 percentage points.\273\ (The estimated increases for younger 
passengers are much lower because they already have high rates of seat 
belt use). For simplicity, we refer to these scenarios as ``Low'' and 
``High,'' or ``3%'' and ``5%.''
---------------------------------------------------------------------------

    \272\ See PRIA, Table 33.
    \273\ See PRIA, Table 33.
---------------------------------------------------------------------------

    Based on these belt and warning system effectiveness estimates, we 
estimate that the proposed rear seat belt warning requirements would 
prevent 22 fatalities and 75 injuries annually under the ``Low'' 
scenario. Under the ``High'' scenario, we estimate that 34 fatalities 
and 112 injuries would be prevented annually.\274\ See table 9. Another 
way to measure benefits is by calculating equivalent lives saved. 
Equivalent lives saved are the number of prevented fatalities added to 
the number of prevented injuries, with the prevented injuries expressed 
in terms of fatalities (that is, with an injury expressed as a fraction 
of a fatality, so that the more serious the injury, the higher the 
fraction). The estimated equivalent lives saved are presented in table 
10.
---------------------------------------------------------------------------

    \274\ See PRIA, Table 47.

 Table 9--Estimated Annual Benefits--Lives Saved and Injuries Prevented
  for Positive-Only SBWS (Rear Seats), With Estimated 3 & 5 Percentage
                       Point Increase in Belt Use
------------------------------------------------------------------------
              Injury level                   3% (low)        5% (high)
------------------------------------------------------------------------
MAIS 1 \275\............................            23.2            34.3
MAIS 2..................................            40.2            60.3
MAIS 3..................................             5.6             8.4
MAIS 4..................................             5.5             8.2
MAIS 5..................................             0.2             0.3
                                         -------------------------------
    Total Injuries......................            74.7           111.5
------------------------------------------------------------------------
Fatal...................................            22.3            33.6
------------------------------------------------------------------------

 Table 10--Estimated Annual Benefits--Equivalent Lives Saved--Positive-
                      Only SBWS (Rear Seats) \276\
------------------------------------------------------------------------
                                            3% Discount     7% Discount
            Belt use increase                  rate            rate
------------------------------------------------------------------------
3% increase.............................            21.9            17.7
5% increase.............................            32.9            26.7
------------------------------------------------------------------------

    We also estimated the costs of the proposed requirements. To comply 
with the minimum proposed requirements (the positive-only compliance 
option), the system would need to have seat belt buckle sensors (to 
determine if the belt is fastened) and wiring and wire conduits to 
provide information on the belt buckle status from the rear seats to 
the computer processor controlling the warning system. Based on the 
results of NHTSA's teardown analysis, we estimate a cost of $6.28 per 
seat. Given an average of 3.12 rear seats per vehicle, this yields a 
final cost of $19.59 per vehicle. Based on this, the cost to the fleet 
to comply with the proposed minimum requirements (the positive-only 
system) is $167.8 million (M).
---------------------------------------------------------------------------

    \275\ The Abbreviated Injury Scale (AIS) is a classification 
system for assessing impact injury severity developed and published 
by the Association for the Advancement of Automotive Medicine and is 
used for coding single injuries, assessing multiple injuries, or for 
assessing cumulative effects of more than one injury. MAIS 
represents the maximum injury severity of an occupant at an AIS 
level, i.e., the highest single AIS for a person with one or more 
injuries. MAIS 1 & 2 injuries are considered minor injuries and MAIS 
3-5 are considered serious injuries.
    \276\ See PRIA, Table 72.
---------------------------------------------------------------------------

    Based on the forgoing, we performed benefit-cost and cost-
effectiveness analyses. A benefit-cost analysis calculates net 
benefits, which is the difference between the benefits flowing from 
injury and fatality reductions and the cost of the rule. Our net 
benefit estimates are presented in table 11. The cost-effectiveness 
analysis derives the cost per equivalent life saved, which is equal to 
the total cost of the rule divided by the total fatal equivalents that 
it prevents. These estimates are presented in table 12.
---------------------------------------------------------------------------

    \277\ See PRIA, Table 79.

      Table 11--Net Benefits--Positive-Only SBWS (Rear Seats) \277\
                       [2020 Dollars, in millions]
------------------------------------------------------------------------
                                            3% Discount     7% Discount
   Seat position and belt use increase         rate            rate
------------------------------------------------------------------------
3% increase.............................           $95.6           $46.2
5% increase.............................           228.3           153.9
------------------------------------------------------------------------

[[Page 61723]]

   Table 12--Cost-Effectiveness Analysis (Cost per Equivalent Life Saved)--Proposed Positive-Only System \278\
                                           [2020 Dollars, in millions]
----------------------------------------------------------------------------------------------------------------
               Seat position and belt use increase                      ELS            Cost          Cost/ELS
----------------------------------------------------------------------------------------------------------------
                                                3% Discount Rate
----------------------------------------------------------------------------------------------------------------
3% increase.....................................................            21.9          $166.4            $7.6
5% increase.....................................................            32.9           166.4             5.0
----------------------------------------------------------------------------------------------------------------
                                                7% Discount Rate
----------------------------------------------------------------------------------------------------------------
3% increase.....................................................            17.7          $166.4            $9.4
5% increase.....................................................            26.7           166.4             6.2
----------------------------------------------------------------------------------------------------------------

2. Front Seat Belt Warning System
    Based on FARS and NASS-GES data from 2011 to 2015, on average 7,503 
unrestrained drivers and 1,453 unrestrained front outboard passengers 
of passenger cars and light trucks were killed annually in traffic 
crashes. Additionally, 53,113 unrestrained drivers and 10,324 
unrestrained front outboard passengers were, on average, injured 
annually. After adjusting these to account for future decreases in 
fatalities and injuries projected to occur in the absence of the 
proposed requirements due to the introduction of other mandatory safety 
technologies (e.g., electronic stability control), there were, on 
average, 6,733 fatalities and 47,952 injuries to unrestrained front 
seat occupants each year. This is the overall target population--the 
annual deaths and injuries that the proposed requirements are aimed at 
reducing.
---------------------------------------------------------------------------

    \278\ See PRIA, Table 73.
---------------------------------------------------------------------------

    According to the NOPUS, 90.6% of the drivers used the seat belt in 
2021, which is slightly higher when compared to passengers in the 
right-front seating position with an observed belt use rate of 
89.4%.\279\ In order to estimate the percentage of drivers and front 
passengers who do not always use a seat belt, we used the results from 
a 2004 analysis using data from the Household Component of the 2002 
Medical Expenditure Panel Survey (MEPS-HC) \280\ that found that among 
persons 16-64 years of age, 87.7 percent reported always or nearly 
always using seat belts when driving or riding in a car. Another 6.9 
percent reported sometimes using seat belts, while 5.4 percent reported 
seldom or never using seat belts when driving or riding in a car. These 
results are summarized in table 13. This means, when an observation is 
made about the percentage of drivers who use the seat belts, the 
observed belt use rate is higher than 87.7% since the other groups 
would contribute to the observed belt use rate although they are not 
always using the seat belts. NHTSA recognizes that driving habits may 
or may not have changed since 2002 as seat belt use rates have 
increased and as new generations of drivers and passengers are on the 
road. NHTSA considered, but tentatively decided not to use, the results 
of more recent studies, such as the (2016) Motor Vehicle Occupant 
Safety Survey \281\ to estimate the percentage of drivers and front 
passengers who do not always use a seat belt. While the 2016 MVOSS is 
more recent, we decided to use the 2004 study because we tentatively 
concluded that the data provided by the 2004 study best suited the 
needs of our analysis. Given that most data on seat belt use is self-
reported, the 2004 study has a high sample size (approximately 25,000) 
\282\ and provides robust categorizations of seat belt use that fits 
the needs of our analysis. Furthermore, when comparing this data to the 
findings of the 2016 MVOSS, we did not find evidence that these trends 
have significantly changed over time.\283\ NHTSA seeks comment on 
instead using the results of more recent studies, such as the 2016 
MVOSS, or other data sources commenters are able to identify.
---------------------------------------------------------------------------

    \279\ National Center for Statistics and Analysis. (2021, 
December). Seat belt use in 2021--Overall results (Traffic Safety 
Facts Research Note. Report No. DOT HS 813 241). National Highway 
Traffic Safety Administration.
    \280\ May Chu, ``Statistical brief #62: Characteristics of 
Persons Who Seldom or Never Wear Seat Belts 2002.'' https://meps.ahrq.gov/data_files/publications/st62/stat62.pdf.
    \281\ Spado, D., Schaad, A., & Block, A. (2019, December). 2016 
motor vehicle occupant safety survey; Volume 2: Seat belt report 
(Report No. DOT HS 812 727). National Highway Traffic Safety 
Administration.
    \282\ Compared to the 2016 MVOSS, which had, depending on the 
question, sample sizes of approximately 5,000 to 10,000.
    \283\ For example, the 2016 MVOSS found that about 6% of drivers 
reported using their belt sometimes (most of the time or some of the 
time. See pg. 7 (Fig. 5) in the MVOSS.

                 Table 13--Seat Belt Use Characteristics
------------------------------------------------------------------------
               Belt user and related items                   Rate (%)
------------------------------------------------------------------------
A reported ``sometimes using seat belts''...............             6.9
A reported ``seldom or never using seat belts when                   5.4
 driving or riding in a car''...........................
Percentage of drivers who always use seat belts,                    87.7
 calculated.............................................
                                                         ---------------
    Total...............................................           100.0
------------------------------------------------------------------------

    As we did for the rear seats, NHTSA estimated the effectiveness and 
benefits associated with requiring a seat belt warning system that 
remains activated until the seat belts are buckled for the driver and 
front outboard passenger seats. In developing this estimate, NHTSA used 
the results of a study conducted by the Insurance Institute for Highway 
Safety (IIHS) by Kidd et al. (2019) \284\ In the Kidd et al. (2019) 
study, part-time belt users (who had a recent seat belt citation and 
reported not always using a seat belt) drove two vehicles for a certain 
period of time, a Chevrolet with three intermittent 7-second audible 
warnings followed by either a BMW with a 100-second audible warning 
(n=17) or a Subaru with an audible warning that continues until the 
seat belt is buckled (n=16). (All of the vehicles provided a visual 
warning that lasted until the seat belt was buckled.) Kidd et al. found 
that, relative to the intermittent reminder (i.e., 7-second audible 
reminder), the BMW warning with the 100-second audible reminder 
increased seat belt use by 30% and the Subaru warning with

[[Page 61724]]

the indefinite audible warning increased belt use by 34%.\285\
---------------------------------------------------------------------------

    \284\ ``The effects of persistent audible seat belt reminders 
and a speed-limiting interlock on the seat belt use of drivers who 
do not always use a seat belt,'' April 2019, David G. Kidd Insurance 
Institute for Highway Safety, Jeremiah Singer Westat, Inc.
    \285\ There were several limitations in this study, the main one 
being that the number of study participants was small, and, 
consequently, there was limited statistical power when comparing the 
change in rate of belt use between the different vehicle technology 
conditions. The study further discusses this and other limitations, 
such as how the demographics of the study sample differs from part-
time belt users nationwide.
---------------------------------------------------------------------------

    NHTSA estimates, based on the NOPUS, Chu, and IIHS studies, that a 
requirement for an indefinite duration audible seat belt warning would 
increase the overall observed seat belt use rate by 2.8 percentage 
points for the driver and 2.4 percentage points for the front outboard 
passenger from current observed seat belt use levels.
    NHTSA also reviewed manufacturer data for model year 2020 vehicles 
to determine market penetration of indefinite duration seat belt 
warning systems in the front outboard seats and that of a 90-second or 
greater duration warning and obtained the estimates in table 14.

  Table 14--Market Penetration of Different Duration Seat Belt Audible
                             Warning Systems
------------------------------------------------------------------------
                                                           Percentage of
                       SBWS system                             sales
------------------------------------------------------------------------
<90 second warning......................................             7.6
90 second and 90+ but not indefinite....................            85.2
Enhanced--Warning until seat belt is buckled............             7.2
------------------------------------------------------------------------

    For front seat occupants, seat belts reduce the risk of fatality by 
44% (for passenger cars) and 73% (for light trucks and vans).\286\ Seat 
belts reduce the risk of moderate to greater severity injuries by up to 
50%.\287\
---------------------------------------------------------------------------

    \286\ See PRIA, Table 30.
    \287\ See PRIA, Table 30.
---------------------------------------------------------------------------

    Based on the estimated seat belt warning system effectiveness in 
increasing seat belt use, the market penetration of different duration 
seat belt audible warning systems, and the effectiveness of seat belts 
in mitigating fatalities and injuries, NHTSA estimates that requiring 
an audio-visual seat belt warning that remains activated until the seat 
belt is buckled (indefinite duration) would prevent 65 driver 
fatalities, 11 front outboard passenger fatalities, and a total of 211 
injuries annually, as shown in table 15. This results in 92 equivalent 
lives saved (Table 16).

 Table 15--Estimated Annual Benefits--Lives Saved and Injuries Prevented--Indefinite SBWS (Front Outboard Seats)
----------------------------------------------------------------------------------------------------------------
                                                                                       Front
                          Injury level                                Driver         passenger         Total
----------------------------------------------------------------------------------------------------------------
MAIS 1..........................................................            20.7             3.7            24.4
MAIS 2..........................................................           120.0            20.5           140.5
MAIS 3..........................................................            21.6             3.9            25.5
MAIS 4..........................................................            17.4             3.1            20.5
MAIS 5..........................................................             0.5             0.1             0.6
                                                                 -----------------------------------------------
    Total Injuries..............................................           180.2            31.2           211.4
----------------------------------------------------------------------------------------------------------------
Fatal...........................................................            65.9            11.4            77.3
----------------------------------------------------------------------------------------------------------------

    The estimated annual benefits in terms of equivalent lives saved is 
shown in Table 17.

                  Table 16--Estimated Annual Benefits--Equivalent Lives Saved--Indefinite SBWS
                                             [Front Outboard Seats]
----------------------------------------------------------------------------------------------------------------
                                                                                    3% Discount     7% Discount
                                                                   Undiscounted        rate            rate
----------------------------------------------------------------------------------------------------------------
Driver..........................................................            78.7            65.2            52.8
Front Passenger.................................................            13.6            11.3             9.2
                                                                 -----------------------------------------------
    Total.......................................................            92.3            76.5            62.0
----------------------------------------------------------------------------------------------------------------

    We also estimated the costs of the proposed requirements. Since all 
driver seats are required to have at least the basic warning system, 
the incremental cost of enhanced seat belt warning for the driver seat 
is zero. We assume there would be some labor costs associated with 
software updates needed to extend the warning. However, as this is a 
simple programming change, this cost would be amortized over each 
vehicle's production and is therefore considered de minimis. Though 
there are no requirements for a seat belt warning system for the front 
outboard passenger seat, NHTSA estimates that 96 percent of vehicles 
have seat belt warning systems on the front outboard passenger seat. 
NHTSA estimated the cost of equipping a seat belt warning system in the 
front outboard passenger seat to be $2.13 per seat. Therefore, the cost 
of equipping the remaining 4 percent of the 16 million new vehicle 
fleet is $1.36 million (= 16 million x 4 percent x $2.13).
    Based on the foregoing, we performed benefit-cost and cost-
effectiveness analyses. The estimated net benefits are presented in 
table 17 and the cost-effectiveness estimates are presented in Table 
18.

[[Page 61725]]

                           Table 17--Annual Monetized Benefits, Costs and Net Benefits--Indefinite SBWS (Front Outboard Seats)
                                                               [2020 dollars, in millions]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               Driver                          Front passenger              Driver and Front Passenger
                                                --------------------------------------------------------------------------------------------------------
                                                 Undiscounted      3%         7%     Undiscounted      3%         7%
--------------------------------------------------------------------------------------------------------------------------------------------------------
Passenger Car Benefits.........................        $422.5     $353.0     $288.0         $79.9      $66.7      $54.4     $502.4     $419.7     $342.4
Light Truck & Van Benefits.....................         520.4      427.6      344.8          83.4       68.5       55.2      603.8      496.1        400
                                                --------------------------------------------------------------------------------------------------------
    Total Benefits.............................         942.9      780.5      632.8         163.3      135.2      109.7    1,106.2      915.8      742.5
    Total Costs................................             0          0          0          1.36       1.36       1.36       1.36       1.36       1.36
--------------------------------------------------------------------------------------------------------------------------------------------------------
Net Benefits...................................         942.9      780.5      632.8         161.9      133.9      108.3    1,104.8      914.4      741.1
--------------------------------------------------------------------------------------------------------------------------------------------------------

 Table 18--Cost-Effectiveness Analysis (Cost per Equivalent Life Saved)--Indefinite SBWS (Front Outboard Seats)
                                           [2020 dollars, in millions]
----------------------------------------------------------------------------------------------------------------
                          Discount rate                                 ELS            Cost          Cost/ELS
----------------------------------------------------------------------------------------------------------------
3%..............................................................            76.5           $1.36          $0.018
7%..............................................................            62.0            1.36           0.022
----------------------------------------------------------------------------------------------------------------

3. Overall Benefits and Costs of Proposal
    In Table 19, we combine the benefits and costs for the proposed 
rear and front seat belt warning requirements. We estimate positive net 
benefits under all discount rates and effectiveness estimates.

     Table 19--Net Benefits From the Proposal (SBWS for Rear Seating
   Positions and Indefinite SBWS for Front Outboard Seating Positions)
                       [2020 dollars, in millions]
------------------------------------------------------------------------
                                            3% Discount     7% Discount
                                               rate            rate
------------------------------------------------------------------------
Front Outboard Seats....................          $914.4          $741.1
Rear Seats (3% increase in rear seat                95.6            46.2
 belt use)..............................
Rear Seats (5% increase in rear seat               228.3           153.9
 belt use)..............................
Total Net Benefits (3% increase in rear          1,010.0           787.4
 belt use)..............................
Total Net Benefits (5% increase in rear          1,142.7           895.0
 belt use)..............................
------------------------------------------------------------------------

    In Table 20, we combine the equivalent lives saved and cost for the 
proposed rear and front seat belt warning requirements to determine the 
cost per equivalent life saved.

 Table 20--Cost per Equivalent Lives Saved From the Proposal (SBWS for Rear Seating Positions and Indefinite SBWS for Front Outboard Seating Positions)
                                                               [2020 dollars, in millions]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         3% Discount rate                                7% Discount rate
                                                         -----------------------------------------------------------------------------------------------
                    Category                         %                                       Cost per                                        Cost per
                                                            Equivalent         Cost         equivalent      Equivalent         Cost         equivalent
                                                            lives saved                     lives saved     lives saved                     lives saved
--------------------------------------------------------------------------------------------------------------------------------------------------------
Rear Seat Occupants.............................       3            21.9          $166.4           $7.61            17.7          $166.4           $9.38
                                                       5            32.9                            5.05            26.7                            6.23
Front Seat Occupants............................                    76.5             1.4           0.018            62.0             1.4           0.022
    Total.......................................       3            98.4           167.8            1.71            79.7           167.8            2.11
                                                       5           109.4                            1.53            88.7                            1.89
--------------------------------------------------------------------------------------------------------------------------------------------------------

B. Regulatory Alternatives

    In the preceding sections of this document, we discussed various 
alternatives for different aspects of the proposed requirements. In 
Section XIII, Regulatory Alternatives, we identified five major 
alternatives that we considered. We quantified the costs and benefits 
of three of these alternatives (rear-seat occupant detection, a 90-
second front outboard seat belt warning, and front center seat belt 
warning). Below, we briefly summarize our results. For a more detailed 
discussion, the reader is referred to the Preliminary Regulatory Impact 
Analysis in the docket for this rulemaking.
1. Occupant Detection in Rear Seats
    For the rear seat belt reminder, NHTSA is proposing to specify 
three

[[Page 61726]]

different compliance options. One of these (the positive-only system) 
would not necessitate occupant detection, while the other two (the 
negative-only and full-status) would necessitate occupant detection. 
NHTSA estimated the costs and benefits of requiring a system with 
occupant detection.
    NHTSA's teardown analysis indicates that occupant detection 
components cost $39.75 per vehicle, which, added to the $19.59 per 
vehicle cost of the buckle sensor, results in a combined warning system 
cost of $59.33 per vehicle (2020 $). NHTSA estimates that about 47 
percent of new vehicles have a SBWS for the rear seating positions and 
7 percent of new vehicles have occupant detection in rear seats. If 
NHTSA selected the regulatory alternative where occupant detection is 
required, this would result in a total cost of $757.7M. This cost 
estimate is based on the assumption that 53 percent of new vehicles 
would need to install a seat belt sensor in the rear seats and 93 
percent would need to also install occupant detection in the rear seats 
to comply with the regulatory requirement.
    Because there is uncertainty in how much more effective a SBWS with 
occupant detection would be in increasing seat belt use compared to the 
already estimated increase in seat belt use with the proposed SBWS 
without occupant detection, NHTSA did not conduct a cost-effectiveness 
and net benefits analysis. Instead, NHTSA estimated the minimum 
increase in seat belt use for this regulatory alternative that would 
result in overall benefits equal to the overall costs (zero net 
benefits). The agency estimated that seat belt use for rear seat 
occupants 11 years and older would need to increase by approximately 
9.4 percent when discounted at 3 percent and 11.6 percent when 
discounted at 7 percent for this regulatory alternative to result in 
zero net benefits. Therefore, increase in seat belt use from this 
regulatory alternative would need to be greater than 9.4 percent at 3 
percent discount rate and greater than 11.6 percent at 7 percent 
discount rate for positive net benefits. A 9 to 12 percent increase in 
seat belt use is about 2 to 3 times greater than that estimated for the 
proposed SBWS requirement. The SBWS considered under this regulatory 
alternative are capable of letting the driver know, for occupied rear 
seats, either which occupants are not using their seat belts or how 
many of the rear seat occupants are not using their seat belts. While 
we would expect some possible increase in seat belt use from that 
specific functionality, it is doubtful that it would double or triple 
the increase in seat belt use estimated for SBWS without occupant 
detection. Therefore, we do not expect this regulatory alternative to 
be cost-effective or net beneficial.
2. 90-Second Front Outboard Seat Belt Warning
    NHTSA also estimated the costs and benefits if it were to require a 
90-second audio-visual warning for the front outboard seats instead of 
the proposed requirement for a warning that lasts until the belt and 
any occupied seat is buckled. NHTSA estimated the benefits in a similar 
manner as that for the proposed seat belt warning for front seat 
occupants where the warning remains on until the seat belt is buckled. 
One difference is that, for the 90-second duration alternative, we 
assumed that the drivers and passengers who identify as never using a 
seat belt would likely not use the seat belt with a 90-second duration 
warning. Another difference is that this alternative only affects 7.6 
percent of the vehicle fleet with front seat occupant seat belt warning 
with duration less than 90 seconds.
    The benefits of this alternative are presented in Table 21.

  Table 21--Injuries Prevented, Lives Saved, and Equivalent Lives Saved in Front Outboard Seats by a 90-Second
                                                  Duration SBWS
----------------------------------------------------------------------------------------------------------------
                                                      Injuries and fatalities         Equivalent lives saved
                                                             prevented           -------------------------------
                  Injury level                   --------------------------------
                                                                       Front          Driver           Front
                                                      Driver         passenger                       passenger
----------------------------------------------------------------------------------------------------------------
MAIS 1..........................................            1.84            0.22            0.01            0.00
MAIS 2..........................................            9.85            1.18            0.46            0.05
MAIS 3..........................................            1.77            0.22            0.19            0.02
MAIS 4..........................................            1.43            0.18            0.38            0.05
MAIS 5..........................................            0.04            0.00            0.02            0.00
Fatal...........................................            5.29            0.65            5.29            0.65
    Total.......................................  ..............  ..............            6.34            0.77
----------------------------------------------------------------------------------------------------------------

    About 7 equivalent lives are saved by this alternative, which is 
significantly lower than the 86 equivalent lives saved by a warning 
that remains on until the seat belt is buckled. The cost of this 
alternative is the same as that for the proposed warning. The only cost 
is that for the 4 percent of vehicles without a seat belt warning 
system in the front outboard passenger seat (cost = $1.36 million). The 
annual monetized benefits, costs, and net benefits of this alternative 
are shown in Table 22.

                 Table 22--Annual Monetized Benefits, Costs and Net Benefits for a 90-Second Duration SBWS in Front Outboard Seats \288\
                                                               [2020 dollars, in millions]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Driver                          Front passenger               Driver and front passenger
                Vehicle type                 -----------------------------------------------------------------------------------------------------------
                                              Undiscounted      3%         7%     Undiscounted      3%         7%     Undiscounted      3%         7%
--------------------------------------------------------------------------------------------------------------------------------------------------------
PC..........................................         $35.3      $29.5      $25.4          $4.7       $3.9       $3.2         $40.0      $33.4      $27.2
LTV.........................................          40.7       33.4       26.9           4.6        3.8        3.1          45.2       37.2       30.0
                                             -----------------------------------------------------------------------------------------------------------
    Total Benefits..........................          75.9       62.9       51.0           9.3        7.7        6.2          85.2       70.6       57.2
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 61727]]

 
Costs.......................................             0          0          0          1.36       1.36       1.36          1.36       1.36       1.36
Net Benefits................................          75.9       62.9       51.0           7.9        6.3        4.9          83.8       69.2       55.9
--------------------------------------------------------------------------------------------------------------------------------------------------------

    While this regulatory alternative is cost effective, the benefits 
are significantly lower than that of the proposed warning.
---------------------------------------------------------------------------

    \288\ See PRIA, Table 92.
---------------------------------------------------------------------------

3. Seat Belt Warning for Front Center Seat
    The agency also considered requiring a seat belt warning system for 
the front center seating position. To estimate incremental benefits, 
NHTSA used the 2011-2015 FARS data, the adjustment factors to account 
for safety impacts of new required safety technologies, and the injury-
to-fatality ratios by injury severity to establish the target 
population addressed by this regulatory alterative (Table 23).

           Table 23--Annual Adjusted Fatalities and Non-Fatal Injuries to Front Center Seat Passengers
----------------------------------------------------------------------------------------------------------------
             Vehicle type                    Injury severity        Restrained     Unrestrained        Total
----------------------------------------------------------------------------------------------------------------
PC....................................  MAIS 1..................              11              15              26
                                        MAIS 2..................               5               7              11
                                        MAIS 3..................               1               2               3
                                        MAIS 4..................               1               1               2
                                        MAIS 5..................               0               0               0
                                                                 -----------------------------------------------
                                        Total Injuries (MAIS 1-               18              25              43
                                         5).
                                        Fatal...................               2               3               6
----------------------------------------------------------------------------------------------------------------
LTV...................................  MAIS 1..................              23             112             135
                                        MAIS 2..................               8              38              46
                                        MAIS 3..................               0               0               0
                                        MAIS 4..................               0               2               2
                                        MAIS 5..................               0               0               0
                                                                 -----------------------------------------------
                                        Total Injuries (MAIS 1-               31             152             183
                                         5).
                                        Fatal...................               5              23              28
----------------------------------------------------------------------------------------------------------------

    Due to a lack of data, NHTSA is unable to establish the seat belt 
use rate for front center passengers under the baseline. Also, due to 
this limitation, the agency cannot estimate the increase in seat belt 
use rates under this regulatory alternative. Since front center seat 
passengers are most similar to right front seat passengers, NHTSA used 
the effectiveness rates calculated for indefinite duration seat belt 
warning system for the front outboard passenger seat to estimate 
incremental benefits as shown in Table 24.

          Table 24--Incremental Benefits for Indefinite Duration SBWS in Front Center Seating Position
----------------------------------------------------------------------------------------------------------------
                                                                                Calculated
                                                                             effectiveness of
                                                                                indefinite
                    Injury severity                      Observed injuries  duration SBWS for     Incremental
                                                                              front outboard        benefits
                                                                             passenger seats
                                                                                   (%)
----------------------------------------------------------------------------------------------------------------
                                                 Passenger Cars
----------------------------------------------------------------------------------------------------------------
MAIS 1.................................................                 26               0.03             0.0078
MAIS 2.................................................                 11               0.41             0.0466
MAIS 3.................................................                  3               0.41             0.0129
MAIS 4.................................................                  2               0.41             0.0093
MAIS 5.................................................                  0               0.41             0.0002
Fatal..................................................                  6               0.43             0.0241
----------------------------------------------------------------------------------------------------------------
                                                      LTVs
----------------------------------------------------------------------------------------------------------------
MAIS 1.................................................                135               0.03             0.0405

[[Page 61728]]

 
MAIS 2.................................................                 46               0.41             0.1878
MAIS 3.................................................                  0               0.41             0.0012
MAIS 4.................................................                  2               0.41             0.0088
MAIS 5.................................................                  0               0.41             0.0006
Fatal..................................................                 28               0.43             0.1203
----------------------------------------------------------------------------------------------------------------

    The cost for front center passenger seats would include the cost 
for a buckle sensor and occupant detection. Therefore, the cost per 
vehicle for this regulatory alternative is $14.86 in 2020 dollars. This 
cost estimate reflects a cost of $2.13 to add a buckle sensor and the 
cost to add occupant detection for $12.73.
    In assessing the number of vehicles that would be impacted by this 
regulatory alternative, we consider that the front center seat is not a 
common feature in new light vehicles. Based on our engineering 
judgement, we expect that 800,000 vehicles or five percent of the new 
vehicle fleet include a center seating position. Table 25 presents the 
total cost to meet the requirements under this regulatory alternative 
for an indefinite duration SBWS for front center passenger seats.

    Table 25--Total Cost of Indefinite Duration SBWS for Front Center
                             Passenger Seats
------------------------------------------------------------------------
                                          Per vehicle
      Number of vehicles impacted             cost          Total cost
------------------------------------------------------------------------
800,000...............................          $14.86      $11,888,000
------------------------------------------------------------------------

    Table 26 presents the of the cost-effectiveness analysis and Table 
27 presents the benefit-cost analysis for this regulatory alternative. 
When discounted at three and seven percent, the cost per ELS is 
approximately $88.9 million and $110.0 million, respectively and the 
net benefits are negative for this regulatory alternative. Because the 
cost per ELS is higher than the comprehensive cost of a fatality and 
the net benefits are negative, this regulatory alternative is not cost-
effective.

                                       Table 26--Cost-Effectiveness Analysis for SBWS Front Center Seat Passengers
                                                                       [Millions]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Discounted at 3%                                   Discounted at 7%
                                                   -----------------------------------------------------------------------------------------------------
                     Category                                                             Cost per                                           Cost per
                                                       Equivalent          Cost          equivalent       Equivalent          Cost          equivalent
                                                      lives saved                       lives saved      lives saved                       lives saved
--------------------------------------------------------------------------------------------------------------------------------------------------------
Front Center Seat.................................          0.1337           $11.89           $88.91           0.1081           $11.89          $110.00
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                          Table 27--Benefit-Cost Analysis for SBWS Front Center Seat Passengers
                                                                       [Millions]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Discounted at 3%                                   Discounted at 7%
                                                   -----------------------------------------------------------------------------------------------------
                     Category                          Monetized                                          Monetized
                                                        benefits           Cost         Net benefits       benefits           Cost         Net benefits
--------------------------------------------------------------------------------------------------------------------------------------------------------
Front Center Seat.................................           $1.60           $11.89          -$10.29            $1.29           $11.89          -$10.59
--------------------------------------------------------------------------------------------------------------------------------------------------------

XV. Proposed Effective Date

    We received one comment responding to the ANPRM on the effective 
date. The commenter said that adequate lead-time and phase-ins should 
be provided. With respect to eliminating the eight-second limitation 
for the front seat requirements, the commenter stated that R16 and the 
corresponding FMVSS requirements are safety neutral, so compliance with 
either of these requirements should be permitted for a sufficient 
period of time to permit the orderly phase-out of current models with 
long product refresh cycle durations.
    In order to accelerate the fleet penetration of the proposed seat 
belt warning requirements and to achieve the associated benefits as 
quickly as reasonably possible, NHTSA proposes an effective date of the 
first September 1 that is one year after the publication of the final 
rule for the front seat belt warning system requirements and the first 
September 1 that is two years after the publication of the final rule 
for the

[[Page 61729]]

rear seat belt warning system requirements, with optional early 
compliance permitted. For example, if the final rule were published on 
October 1, 2022, the effective date would be September 1, 2024, for the 
front seat belt warning system requirements and September 1, 2025, for 
the rear seat belt warning system requirements. Consistent with 49 CFR 
571.8(b), multi-stage manufacturers and alterers would have an 
additional year to comply.
    To equip vehicles with one of the proposed rear seat belt warning 
systems, a manufacturer could utilize existing vehicle components such 
as door sensors, audible signals, and the center console display. 
Integrating a rear seat belt warning system in vehicles would require 
equipping the rear seats with certain components most vehicles do not 
already have, such as the appropriate seat belt use sensing technology 
(seat belt latch sensors, which are readily available). Manufacturers 
would also have to redesign the hardware and software as necessary to 
incorporate the required signals, incorporate new visual signals in the 
instrument panel (if the visual signal is located there) and validate 
the performance of these components and systems. These endeavors take 
time, which we estimate to be two years.
    On the other hand, almost all vehicles (96%) already have a front 
outboard passenger seat belt warning system. The majority of vehicle 
manufacturers would simply have to make software adjustments necessary 
to ensure it meets the proposed requirements. Occupant detection 
technology is readily available and the majority of the front outboard 
passenger seats already have a seat belt warning or occupant sensing 
technology needed to meet the proposed requirements. We acknowledge 
that a small portion of vehicles (4%) that do not have a front outboard 
passenger seat belt warning system will require hardware and software 
adjustments, but this is not a new technology and we believe 
manufacturers can focus their resources accordingly to meet the front 
seat belt warning system requirements earlier than the rear seat belt 
warning system requirements.
    Overall, the proposed seat belt warning requirements should not 
require much interior redesign, nor should they require the use of much 
new technology. When the FMVSS No. 208 driver seat belt warning was 
first required in 1971, less than a year of lead time was given for 
vehicles that chose a compliance option that required the warning.\289\ 
We believe that the proposed effective dates will provide manufacturers 
with sufficient time to integrate the proposed rear and front passenger 
seat belt warnings (if one is not already in place).
---------------------------------------------------------------------------

    \289\ 36 FR 4600 (Mar. 10, 1971).
---------------------------------------------------------------------------

    At the same time, we appreciate the challenges multi-stage 
manufacturers and alterers may face as a result of these new rear seat 
belt warning requirements in terms of obtaining and implementing the 
necessary hardware. We note, however, that most of the components 
necessary to meet the proposed minimum performance requirements for the 
proposed seat belt warnings are readily available from original 
equipment manufacturers and we do not foresee any major delays in 
obtaining them. In order to provide flexibility to these small 
businesses, and in accordance with 49 CFR 571.8(b), multi-stage 
manufacturers and alterers would have an extra year of lead time.
    We seek comment on these issues. If a commenter believes one year 
does not provide sufficient lead time for the front seat warning, NHTSA 
seeks comment on the types of vehicles for which additional lead time 
is requested and the basis for such a request. Alternatively, if a 
commenter believes the compliance period is too long in light of the 
safety considerations addressed in this NPRM, NHTSA seeks comment on an 
alternative compliance period.

XVI. Regulatory Analyses

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

    We have considered the potential impact of this proposed rule under 
Executive Order 12866, Executive Order 14094, Executive Order 13563, 
DOT Order 2100.6A and the Department of Transportation's regulatory 
policies and procedures.\290\ The Office of Management and Budget has 
determined that this proposed rule is a significant regulatory action 
and was reviewed under section 3(f)(1) of E.O. 12866, as amended by 
E.O. 14094. Pursuant to E.O. 12866 and the Department's policies, we 
have identified the problem this proposed rule addresses, assessed the 
benefits and costs, and considered alternatives. These analyses have 
been summarized in Section VI, Safety Need and Section XIV, Overview of 
Benefits and Costs and are discussed in more detail in the docketed 
preliminary regulatory impact analysis.
---------------------------------------------------------------------------

    \290\ 49 CFR part 5, subpart B; Department of Transportation 
Order 2100.6A, Rulemaking and Guidance Procedures, June 7, 2021.
---------------------------------------------------------------------------

Promoting International Regulatory Cooperation

    The policy statement in section 1 of Executive Order 13609 provides 
that the regulatory approaches taken by foreign governments may differ 
from those taken by the United States to address similar issues, and 
that in some cases the differences between them might not be necessary 
and might impair the ability of American businesses to export and 
compete internationally. It further recognizes that in meeting shared 
challenges involving health, safety, 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 can reduce, eliminate, or prevent unnecessary 
differences in regulatory requirements.
    In addition, section 24211 of the Infrastructure, Investment, and 
Jobs Act, Global Harmonization, provides that DOT ``shall cooperate, to 
the maximum extent practicable, with foreign governments, 
nongovernmental stakeholder groups, the motor vehicle industry, and 
consumer groups with respect to global harmonization of vehicle 
regulations as a means for improving motor vehicle safety.'' \291\
---------------------------------------------------------------------------

    \291\ H.R. 3684 (117th Congress) (2021).
---------------------------------------------------------------------------

    In developing this proposal, our intent was to harmonize with ECE 
R16 and Euro NCAP as much as possible, but deviate where we believed it 
was justified with respect to the Safety Act criteria (need for safety, 
objectivity, practicability). The tentative reasons for following or 
deviating in any of these respects are explained in detail in the 
relevant section of the preamble. In general, we believe that although 
the proposal deviates from R16 in some ways, the two are not 
incompatible, so that it is possible to design a rear reminder system 
that complies with the proposed requirements and is compatible with 
R16. Further, almost all international NCAP programs, including those 
in Europe, Japan, China, Korea, Latin America, Southeast Asia, and 
Australia and New Zealand award points to vehicles that are equipped 
with seat belt warning systems for passenger seating positions. Thus, 
the proposed requirements are consistent with these international 
programs and complement those international efforts to increase seat 
belt use by all vehicle occupants.

Regulatory Flexibility Act

    Pursuant to the Regulatory Flexibility Act (5 U.S.C. 601 et seq., 
as amended by

[[Page 61730]]

the Small Business Regulatory Enforcement Fairness Act (SBREFA) of 
1996), whenever an agency is required to publish an NPRM or final rule, 
it must prepare and make available for public comment a regulatory 
flexibility analysis (RFA) that describes the effect of the rule on 
small entities (i.e., small businesses, small organizations, and small 
governmental jurisdictions). The Small Business Administration's 
regulations at 13 CFR part 121 define a small business, in part, as a 
business entity ``which operates primarily within the United States.'' 
(13 CFR 121.105(a)). No regulatory flexibility analysis is required if 
the head of an agency certifies that the rule will not have a 
significant economic impact on a substantial number of small entities. 
SBREFA amended the Regulatory Flexibility Act to require Federal 
agencies to provide a statement of the factual basis for certifying 
that a rule will not have a significant economic impact on a 
substantial number of small entities.
    NHTSA has considered the effects of this proposed rule under the 
Regulatory Flexibility Act. According to 13 CFR 121.201, the Small 
Business Administration's size standards regulations used to define 
small business concerns, manufacturers of the vehicles covered by this 
final rule would fall under North American Industry Classification 
System (NAICS) No. 336211, Automobile Manufacturing, which has a size 
standard of 1,000 employees or fewer.
    NHTSA estimates that there are three small light vehicle 
manufacturers in the U.S. We estimate that there are several hundred 
second-stage or final-stage manufacturers and alterers that could be 
impacted by a final rule. The agency has analyzed the economic impact 
on these entities. For the reasons discussed below and in the PRIA, we 
tentatively conclude that if made final, this proposed rule would not 
have a significant economic impact on a substantial number of small 
entities.
    The proposed rule would directly affect motor vehicle 
manufacturers. However, we believe that the proposed rule would not 
have a significant economic impact on these entities. Small 
manufacturers are already certifying their vehicle's compliance, for 
the driver position, with FMVSS No. 208's seat belt warning system 
requirements. The means they use to certify to the current requirements 
would be similar to or the same as those they would use to certify to 
the proposed rear seat belt warning requirements.
    Further, the proposed compliance test is a relatively simple test, 
involving a test technician positioning a person or test dummy in a 
seat and checking if the requisite signals activate. Checking to see if 
visual and audible warnings activate for the driver seat belt warning 
system has been a part of FMVSS No. 208 compliance testing for many 
years, and manufacturers are knowledgeable about conducting such tests.
    Small manufacturers have options available to certify compliance, 
none of which will result in a significant economic impact on these 
entities. The manufacturers can and do obtain seating systems from seat 
suppliers and install the seats on the body following the instructions 
of the seat supplier. Seat and seat belt suppliers are large entities 
with resources available to assist small manufacturers in incorporating 
the seat belt warning systems, if manufacturers need technical 
assistance (which we do not think they will need, given the simplicity 
of the systems, particularly those rear systems that do not involve 
occupant detection). We do not believe that current manufacturing 
practices would have to change significantly as a result of a final 
rule.
    In addition, we also believe that the proposed rulemaking would not 
have a significant impact on small and limited-line vehicle 
manufacturers because the market for the vehicles produced by these 
entities is highly inelastic. Purchasers of these vehicles are 
attracted by the desire to have an unusual vehicle. Further, all light 
vehicles would have to comply with the proposed requirements. Since the 
price of complying with the proposed rule would likely be passed on to 
the final consumer, the price of competitor's models would increase by 
similar amounts. Further, we do not believe that raising the price of a 
vehicle to include the cost of a rear seat belt warning system would 
have much, if any, effect on vehicle sales.
    There are a significant number (several hundred) of second-stage or 
final-stage manufacturers and alterers that would be impacted by a 
final rule. These manufacturers buy incomplete vehicles to finish as 
complete vehicles or modify previously-certified vehicles. Many of 
these latter vehicles are van conversions; there are a variety of 
vehicles affected.
    To produce a vehicle, a final-stage manufacturer can either stay 
within the incomplete vehicle document (IVD) furnished by the 
incomplete vehicle manufacturer (which are typically large vehicle 
manufacturers, such as GM or Ford), or the final-stage manufacturer can 
work with incomplete vehicle manufacturers to enable the final-stage 
manufacturer to certify to the new requirements.\292\ The final-stage 
manufacturer can also certify to the standard using due care based on 
an assessment of the information available to the manufacturer.
---------------------------------------------------------------------------

    \292\ For a discussion of NHTSA's certification regulations for 
final stage manufacturers, see 71 FR 28168, May 15, 2006, Docket No. 
NHTSA-2006-24664, Response to petitions for reconsideration of a 
final rule implementing regulations pertaining to multi-stage 
vehicles and to altered vehicles. The Background section of that 
document provides concepts and terminology relating to the 
certification of multi-stage vehicles.
---------------------------------------------------------------------------

    While there are a substantial number of multi-stage manufacturers 
that could be impacted by the proposed rule, we believe that the impact 
on them would not be significant. We note that these manufacturers are 
already certifying their vehicles to FMVSS No. 208's seat belt warning 
system requirements that apply to the driver seating position. They are 
already familiar with the equipment and manufacturing processes 
involved to certify their vehicles to seat belt warning system 
requirements. Further, we anticipate that final-stage manufacturers 
will base their vehicles on incomplete vehicles that already have the 
SBRS installed rather than install the systems themselves.
    For final-stage manufacturers working with incomplete vehicles that 
do not have rear seats or SBRSs already installed, we tentatively 
believe that completing vehicles to meet the proposed requirements 
would be practicable. The manufacturers can obtain seats and seat belt 
systems (with seat belt warning system) from suppliers. NHTSA 
recognizes that the suppliers might be supplying larger vehicle 
manufacturers during the development and lead time period, and do not 
have the capabilities to handle all of the smaller manufacturers, 
including final-stage manufacturers. The rulemaking proposal accounts 
for this limitation by proposing to allow final-stage manufacturers an 
additional year to comply with the proposed requirements, to provide 
flexibility to these small entities and reduce the economic impact of 
the proposed rule on them. (See also 49 CFR 571.8(b).)
    For an alterer (a person who alters by addition, substitution or 
removal of components [other than readily attachable components] a 
certified vehicle before the first purchase of the vehicle other than 
for resale), the impacts of the proposed rule would not be significant. 
The proposed rule would allow alterers an additional year to comply 
with the proposed requirements. If an alterer is removing

[[Page 61731]]

rear seats, the person making the alteration would simply have to be 
careful not to affect the compliance of the seat belt warning system 
for the remaining seats. (See 49 CFR 571.8(b).)
    An alterer that is adding rear seats could obtain seating systems 
with seat belt warning systems from seat suppliers and install the 
seats on the body following the instructions of the seat supplier. 
Changes may have to be made to the instrument panel area to add the 
requisite visual signal, but the proposed rule provides flexibility to 
manufacturers in providing the visual signal.

Executive Order 13132 (Federalism)

    NHTSA has examined this proposed rule pursuant to Executive Order 
13132 (64 FR 43255; Aug. 10, 1999) and concluded that no additional 
consultation with States, local governments, or their representatives 
is mandated beyond the rulemaking process. The agency has concluded 
that the proposed rule does not have sufficient federalism implications 
to warrant consultation with State and local officials or the 
preparation of a federalism summary impact statement. The proposed rule 
does 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 have preemptive effect 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 address the same aspect of performance.
    The express preemption provision described above is subject to a 
savings clause under which ``[c]compliance with a motor vehicle safety 
standard prescribed under this chapter does not exempt a person from 
liability at common law.'' 49 U.S.C. 30103(e). Pursuant to this 
provision, State common law tort causes of action against motor vehicle 
manufacturers that might otherwise be preempted by the express 
preemption provision are generally preserved. However, the Supreme 
Court has recognized the possibility, in some instances, of implied 
preemption of 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 the 
existence of 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, 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 proposed 
rule and does not foresee any potential State requirements that might 
conflict with it. NHTSA does not intend that this proposed rule preempt 
state tort law that would effectively impose a higher standard on motor 
vehicle manufacturers than that established by this proposed rule. 
Establishment of a higher standard by means of State tort law would not 
conflict with the standards proposed in this NPRM. Without any 
conflict, there could not be any implied preemption of a State common 
law tort cause of action.

National Environmental Policy Act

    NHTSA has analyzed this NPRM for the purposes of the National 
Environmental Policy Act. The agency has determined that implementation 
of this action would not have a significant impact on the quality of 
the human environment.

Executive Order 12988 (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 issue of 
preemption is discussed above in connection with E.O. 13132. 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

    Under the procedures established by the Paperwork Reduction Act of 
1995 (PRA) (44 U.S.C. 3501, et. seq.), Federal agencies must obtain 
approval from the OMB for each collection of information they conduct, 
sponsor, or require through regulations. 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. In this NPRM, NHTSA is 
proposing new information collection requirements. The OMB has 
promulgated regulations describing the process through which an agency 
may request and receive clearance for its information collections. 
Under OMB's regulation (at 5 CFR 1320.8(d)), an agency must ask for 
public comment on the following: (a) whether the proposed collection of 
information is necessary for the proper performance of the functions of 
the agency, including whether the information will have practical 
utility; (b) the accuracy of the agency's estimate of the burden of the 
proposed collection of information, including the validity of the 
methodology and assumptions used; (c) how to enhance the quality, 
utility, and clarity of the information to be collected; and (d) how to 
minimize the burden of the collection of information on those who are 
to respond, including the use of appropriate automated,

[[Page 61732]]

electronic, mechanical, or other technological collection techniques or 
other forms of information technology, e.g. permitting electronic 
submission of responses. In compliance with these requirements, NHTSA 
asks for public comments on the Information Collection Request (ICR) 
described below for a revision to NHTSA's existing clearance titled 
``Consolidated Vehicle Owner's Manual Requirements for Motor Vehicles 
and Motor Vehicle Equipment'' (OMB Control No. 2127-0541, which is 
being forwarded to OMB for review and approval.
    Title: Consolidated Vehicle Owner's Manual Requirements for Motor 
Vehicles and Motor Vehicle Equipment.
    OMB Control Number: 2127-0541.
    Type of Request: Revision of a previously approved collection.
    Type of Review Requested: Regular.
    Requested Expiration Date of Approval: 3 years from the date of 
approval.
    Summary of the Collection of Information:
    The National Traffic and Motor Vehicle Safety Act authorizes the 
Secretary of Transportation (NHTSA by delegation), at 49 U.S.C. 30111, 
to issue Federal Motor Vehicle Safety Standards (FMVSS) that set 
performance standards for motor vehicles and items of motor vehicle 
equipment. Further, the Secretary (NHTSA by delegation) is authorized, 
at 49 U.S.C. 30117, to require manufacturers to provide information to 
first purchasers of motor vehicles or items of motor vehicle equipment 
related to performance and safety in printed materials that are 
attached to or accompany the motor vehicle or item of motor vehicle 
equipment. NHTSA has exercised this authority to require manufacturers 
to provide certain specified safety information to be readily available 
to consumers and purchasers of motor vehicles and items of motor 
vehicle equipment. This information is most often provided in vehicle 
owners' manuals and the requirements are found in 49 CFR parts 563, 
571, and 575. This information collection request only covers 
requirements or requests to provide information that is not provided 
verbatim in the regulation or standard. The information requirements or 
requests are included in: Part 563, ``Event data recorders;'' FMVSS No. 
108, ``Lamps, reflective devices, and associated equipment;'' FMVSS No. 
110, ``Tire selection and rims;'' FMVSS No. 138, ``Tire Pressure 
Monitoring Systems;'' FMVSS No. 202a, ``Head restraints;'' FMVSS No. 
205, ``Glazing materials;'' FMVSS No. 208, ``Occupant crash 
protection;'' FMVSS No. 210, ``Seat belt assembly anchorages;'' FMVSS 
No. 213, ``Child restraint systems;'' FMVSS No. 225; ``Child restraint 
anchorage systems:'' FMVSS No. 226, ``Ejection mitigation;'' FMVSS No. 
303, ``Fuel System Integrity of Compressed Natural Gas Vehicles;'' 
Sec.  575.103, ``Truck-camper loading;'' Sec.  575.104, ``Uniform tire 
quality grading standards;'' and Sec.  575.105, ``Vehicle rollover.'' 
NHTSA is seeking approval from OMB for a revision of this currently 
approved collection.\293\
---------------------------------------------------------------------------

    \293\ For a full description of the currently approved 
information collection, please see the 60-day notice NHTSA published 
on February 22, 2022 (87 FR 9787) and the 30-day notice NHTSA 
published on October 14, 2022 (87 FR 62489).
---------------------------------------------------------------------------

    In this NPRM, we propose requiring that the owner's manual describe 
the vehicle's seat belt warning system features, including the 
location, format, and meaning of the visual warnings. We also propose 
that the owner's manual include instructions on how to make any manual 
electrical connections for readily removable seats. The need for the 
proposed collection is discussed in Section X.C.7. If the proposed 
requirements are made final, we will ensure we obtain OMB approval for 
the proposed information collection prior to the effective date of the 
final rule.
    Description of the likely respondents: Vehicle manufacturers.
    Estimated Number of Respondents: 52.
    Estimated Total Annual Burden Hours: 10,172.
    This revision would increase the estimated annual burden hours for 
FMVSS No. 208 by 1,544 hours to 4,294 hours (1,544 hours + 2,750 hours) 
and the total estimated annual burden hours to 10,172. The change in 
burden reflects changes as a result of the rulemaking requiring the 
development of new information for the owner's manual amortized over 
the 3 years the information collection is approved for. NHTSA believes 
all manufacturers already have the engineering staff on hand needed to 
write the required instructions, if not already available, which they 
will accomplish in the regular performance of their duties. More 
details on the ICR and burden calculations are found in the 30-day 
notice NHTSA published on October 14, 2022 (87 FR 62489).
    Table 28 provides a summary of the estimated hour burden and 
associated labor costs.

                        Table 28--Estimated Annual Hour Burden and Associated Labor Costs
----------------------------------------------------------------------------------------------------------------
                                                                     Number of
                                                                     responses                       Estimated
                                                     Number of       annually        Estimated     total annual
         Part/section              Brief title      respondents    (i.e., number   total annual   labor costs at
                                                     annually         owner's      burden hours     $50.44/hour
                                                                     manuals)
----------------------------------------------------------------------------------------------------------------
563...........................  Event Data                    22       9,405,000             203         $10,239
                                 Recorders.
571.108.......................  Lighting--VHAD..              34       9,405,000             383          19,319
571.108.......................  Lighting--SABs..              22      15,048,000             613          30,920
571.110.......................  Tire Selection                 0               0               0               0
                                 and Rims.
571.138.......................  Tire Pressure                 22      18,810,000             438          22,093
                                 Monitoring.
571.202a......................  Head Restraints.              22      18,810,000             876          44,185
571.205.......................  Glazing.........              34          19,140             176           8,877
571.208.......................  Crash Protection              22      19,360,000           4,294         216,589
571.210.......................  Belt Anchors....              22      18,810,000             438          22,093
571.213.......................  Child Restraints              22         968,000              20           1,009
571.225.......................  Child Restraint               22      18,810,000             876          44,185
                                 Anchorages.
571.226.......................  Ejection                      22      18,810,000           1,205          60,755
                                 Mitigation.
571.303.......................  CNG Fuel Systems              15          22,000           18.00             908
575.103.......................  Truck-Camper                  18       2,542,100           35.00           1,765
                                 Loading.
575.104.......................  Tire Quality....              34      15,243,030          579.00          29,205

[[Page 61733]]

 
575.105.......................  Utility Vehicles              22       2,970,000           18.00             908
                                                                                 -------------------------------
    Totals....................  ................  ..............  ..............          10,172         513,050
----------------------------------------------------------------------------------------------------------------

    There are no proposed recordkeeping requirements associated with 
this collection of information.
    Estimated total annual costs of the proposed collection of 
information: $8,726,501.
    The FMVSS No. 208 seat belt reminder system owner's manual 
information requirements would require an estimated additional 4 pages 
to cover the general system information and the information on manual 
electrical connections for readily removable rear seats. The only cost 
associated with publishing this information would be the cost of 
printing the required text. NHTSA estimates there are 17,600,000 new 
vehicles each year that include the FMVSS No. 208 occupant crash 
protection information in the owner's manual. Therefore, the estimated 
annual cost to manufacturers would be increased by $755,040 (4 pages x 
300 words per page x $0.00013 per word x .25 cost factor x 1.1 
production factor x 17,600,000 manuals) bringing the total estimated 
annual cost to $8,726,501.
    The total annual cost to the respondents for the currently approved 
collection of information published in vehicles' owner's manuals is 
summarized in table 29 below. More details on the ICR and cost 
calculations are found in the 30-day notice NHTSA published on October 
14, 2022 (87 FR 62489).

                    Table 29--Estimated Annual Costs
------------------------------------------------------------------------
                                                             Estimated
          Part/section                 Brief title        total costs to
                                                            respondents
------------------------------------------------------------------------
563............................  Event Data Recorders...         $30,566
571.108........................  Lighting--VHAD.........          38,208
571.108........................  Lighting--SABs.........         244,530
571.110........................  Tire Selection and Rims               0
571.138........................  Tire Pressure                   244,530
                                  Monitoring Systems.
571.202a.......................  Head Restraints........         733,590
571.205........................  Glazing................             131
571.208........................  Occupant Crash                4,152,720
                                  Protection.
571.210........................  Seat Belt Assembly              244,530
                                  Anchors.
571.213........................  Child Restraints                 15,730
                                  Systems.
571.225........................  Child Restraints                943,800
                                  anchorage systems.
571.226........................  Ejection Mitigation....       1,833,975
571.303........................  Fuel System Integrity                36
                                  of Compressed Natural
                                  Gas Vehicles.
575.103........................  Truck-Camper Loading...          39,657
575.104........................  Uniform Tire Quality            193,205
                                  Grading Standards.
575.105........................  Vehicle Rollover.......          11,293
                                                         ---------------
    Total Costs................  .......................       8,726,501
------------------------------------------------------------------------

    Public Comments Invited: You are asked to comment on any aspects of 
this information collection, including (a) whether the proposed 
collection of information is necessary for the proper performance of 
the functions of the Department, including whether the information will 
have practical utility; (b) the accuracy of the Department's estimate 
of the burden of the proposed information collection; (c) ways to 
enhance the quality, utility and clarity of the information to be 
collected; and (d) ways to minimize the burden of the collection of 
information on respondents, including the use of automated collection 
techniques or other forms of information technology.
    Please submit any comments, identified by the docket number in the 
heading of this document, by the methods described in the ADDRESSES 
section of this document to NHTSA and OMB. Although comments may be 
submitted during the entire comment period, comments received within 30 
days of publication are most useful.

National Technology Transfer and Advancement Act

    Under the National Technology Transfer and Advancement Act of 1995 
(NTTAA) (Pub. L. 104-113), ``all Federal agencies and departments shall 
use technical standards that are developed or adopted by voluntary 
consensus standards bodies, using such technical standards as a means 
to carry out policy objectives or activities determined by the agencies 
and departments.'' Voluntary consensus standards are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, and business practices) that are developed or adopted by 
voluntary consensus standards bodies, such as SAE (formerly, the 
Society of Automotive Engineers). The NTTAA directs this agency to 
provide Congress, through OMB, explanations when the agency decides not 
to use available and applicable voluntary consensus standards.
    While the agency is not aware of any voluntary standards that exist 
regarding the seat belt warnings contemplated in

[[Page 61734]]

this proposed rule, the agency has examined relevant regulations in 
other countries, such as the European Union standard ECE R16. As 
discussed above, although we are not aware of any foreign regulations 
that require seat belt warnings for the front outboard passenger or 
rear seat belts or for the driver seat on small buses, we believe that 
requiring seat belt warnings for these seating positions and for the 
driver seats on small buses meets a safety need and is practicable.

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.

Unfunded Mandates Reform Act

    The Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4) (UMRA) 
requires agencies to prepare a written assessment of the costs, 
benefits, and other effects of proposed or final rules that include a 
Federal mandate likely to result in the expenditures by States, local 
or tribal governments, in the aggregate, or by the private sector, of 
$100 million or more (adjusted annually for inflation with base year of 
1995) in any one year. Adjusting this amount by the implicit gross 
domestic product price deflator for 2022 results in $177 million 
(111.416/75.324 = 1.48). The assessment may be included in conjunction 
with other assessments, as it is here.
    UMRA requires the agency to select the ``least costly, most cost-
effective or least burdensome alternative that achieves the objectives 
of the rule.'' As discussed above, the agency considered alternatives 
to the final rule and has concluded that the requirements are the most 
cost-effective alternatives that achieve the objectives of the rule.
    The proposed rule on SBRS is not likely to result in expenditures 
by State, local or tribal governments of more than $100 million 
annually. However, it is estimated to result in the expenditure by 
automobile manufacturers and/or their suppliers by approximately $168 
million annually. The estimated costs are discussed in Section XIV and 
the PRIA.
    We have tentatively concluded that the requirements we are 
proposing in this NPRM are the most cost-effective alternatives that 
achieve the objectives of the rule.

Plain Language

    Executive Order 12866 and E.O. 13563 require 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 include them 
in your comments on this proposal.

Regulation Identifier Number (RIN)

    The Department of Transportation assigns a regulation identifier 
number (RIN) to each regulatory action listed in the Unified Agenda of 
Federal Regulations. The Regulatory Information Service Center 
publishes the Unified Agenda in April and October of each year. You may 
use the RIN contained in the heading at the beginning of this document 
to find this action in the Unified Agenda.

Privacy Act

    In accordance with 5 U.S.C. 553(c), DOT solicits comments from the 
public to better inform its rulemaking process. DOT posts these 
comments, without edit, to www.regulations.gov, as described in the 
system of records notice, DOT/ALL-14 FDMS, accessible through 
www.dot.gov/privacy. In order to facilitate comment tracking and 
response, we encourage commenters to provide their name, or the name of 
their organization; however, submission of names is completely 
optional. Anyone is able to search the electronic form of all comments 
received into any of our dockets by the name of the individual 
submitting the comment (or signing the comment, if submitted on behalf 
of an association, business, labor union, etc.). You may review DOT's 
complete Privacy Act Statement in the Federal Register published on 
April 11, 2000 (Volume 65, Number 70; Pages 19477-78).

XVII. Public Participation

How do I prepare and submit comments?

    Your comments must be written and in English. To ensure that your 
comments are correctly filed in the Docket, please include the docket 
number indicated in this document in your comments.
    Your comments must not be more than 15 pages long. (49 CFR 553.21). 
We established this limit to encourage you to write your primary 
comments in a concise fashion. However, you may attach necessary 
additional documents to your comments. There is no limit on the length 
of the attachments.
    If you are submitting comments electronically as a PDF (Adobe) 
file, NHTSA asks that the documents be submitted using the Optical 
Character Recognition (OCR) process, thus allowing NHTSA to search and 
copy certain portions of your submissions.
    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.transportation.gov/regulations/dot-information-dissemination-quality-guidelines.

How can I be sure that my comments were received?

    If you wish the Docket 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, the Docket will 
return the postcard by mail.

How do I submit confidential business information?

    You should submit a redacted ``public version'' of your comment 
(including redacted versions of any additional documents or 
attachments) to the docket using any of the methods identified under 
ADDRESSES. This ``public version'' of your comment should contain only 
the portions for which no claim of confidential treatment is made and 
from which those portions for which confidential treatment is claimed 
has been redacted. See below for further instructions on how to do 
this.
    You also need to submit a request for confidential treatment 
directly to the Office of Chief Counsel. Requests for confidential 
treatment are governed by 49 CFR part 512. Your request must set

[[Page 61735]]

forth the information specified in part 512. This includes the 
materials for which confidentiality is being requested (as explained in 
more detail below); supporting information, pursuant to Sec.  512.8; 
and a certificate, pursuant to Sec.  512.4(b) and part 512, appendix A.
    You are required to submit to the Office of Chief Counsel one 
unredacted ``confidential version'' of the information for which you 
are seeking confidential treatment. Pursuant to Sec.  512.6, the words 
``ENTIRE PAGE CONFIDENTIAL BUSINESS INFORMATION'' or ``CONFIDENTIAL 
BUSINESS INFORMATION CONTAINED WITHIN BRACKETS'' (as applicable) must 
appear at the top of each page containing information claimed to be 
confidential. In the latter situation, where not all information on the 
page is claimed to be confidential, identify each item of information 
for which confidentiality is requested within brackets: ``[ ].''
    You are also required to submit to the Office of Chief Counsel one 
redacted ``public version'' of the information for which you are 
seeking confidential treatment. Pursuant to Sec.  512.5(a)(2), the 
redacted ``public version'' should include redactions of any 
information for which you are seeking confidential treatment (i.e., the 
only information that should be unredacted is information for which you 
are not seeking confidential treatment).
    NHTSA is currently treating electronic submission as an acceptable 
method for submitting confidential business information to the agency 
under part 512. Please do not send a hardcopy of a request for 
confidential treatment to NHTSA's headquarters. The request should be 
sent to Dan Rabinovitz in the Office of the Chief Counsel at 
[email protected]. You may either submit your request via email 
or request a secure file transfer link. If you are submitting the 
request via email, please also email a courtesy copy of the request to 
John Piazza at [email protected].

Will the agency consider late comments?

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

How can I read the comments submitted by other people?

    You may read the comments received by the docket 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. Accordingly, 
we recommend that you periodically check the Docket for new material. 
You can arrange with the docket to be notified when others file 
comments in the docket. See www.regulations.gov for more information.

Appendix A--Front Outboard Seat Belt Warnings--Additional Data

    In Section XI we looked at the durations of the visual and audible 
seat belt warnings for the driver and front outboard passenger seats 
provided on new (MY 2022) vehicles. There we tabulated warning 
durations by the proportion of total projected sales of the vehicle 
models within each durational range. In this appendix, we provide a 
brief discussion of, and data for, the warning durations provided in 
new vehicles tabulated by the number of vehicle models within each 
durational range. The results are largely the same but do show some 
differences. The differences could be attributed to lack of projected 
sales data for some vehicle models, but we provide other potential 
explanations below.
    For example, when tabulated by vehicle model instead of as a share 
of total projected sales, a larger proportion of vehicles have a very 
short duration audible seat belt warning. As we saw in the discussion 
in Section XI, only a very small proportion of new vehicles projected 
to be sold have a very short-duration audible warning lasting six or 
eight seconds (about 1% for the driver warning, and .3% for the 
passenger warning). However, the share of vehicles with such short 
warnings is substantially higher when tabulated as a proportion of 
vehicle models (about 17% for the driver warning and 14% for the 
passenger warning) (see Figure A.1). This could be because these 
vehicles are not expected to have a high sales volume.
    The same situation holds for longer duration audible warnings. A 
large proportion of the vehicles projected to be sold provide a warning 
that lasts at least 1.5 min (90 + sec) (92% for the driver warning, 76% 
for the passenger warning), while the share of vehicles with this 
warning duration is substantially lower when tabulated as a proportion 
of vehicle models (about 80% for both the driver and passenger 
warnings) (see Figure A.1). In this case these vehicle models are 
likely high sales volume vehicles. Similar differences are also 
apparent for the visual warning. See Figure A.2.
BILLING CODE 4910-59-P

[[Page 61736]]

[GRAPHIC] [TIFF OMITTED] TP07SE23.005

    We believe the analysis in terms of sales volume is more 
meaningful, because that reflects the number of vehicles that are 
actually equipped with--and occupants that are actually exposed to--
such warnings. For example, while only a small proportion of vehicles 
(about 1% by sales volume) have a very short-duration driver audible 
warning (six or eight seconds), these vehicles account for about 17% of 
vehicle models for which we had data. That is, very short warnings 
appear to be provided in a relatively high proportion of small-volume 
vehicle models. However, the sales volume data better reflects how 
common these short duration warnings are--relatively not that common in 
the sense that only a small proportion of new vehicles sold have these 
very short duration warnings.

List of Subjects in 49 CFR Part 571

    Imports, Motor vehicle safety, Motor vehicles.

Proposed Regulatory Text

    For the reasons discussed in the preamble, the National Highway 
Traffic Safety Administration proposes to amend 49 CFR part 571 as 
follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

Subpart B--Federal Motor Vehicle Safety Standards

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

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

0
2. Amend Sec.  571.101 by:
0
a. Revising paragraph S5.5.6; and
0
b. Revising table 1 and table 2.
    The revisions read as follows.

Sec.  571.101  Standard No. 101; Controls and displays.

* * * * *
    S5.5.6(a) Except as provided in S5.5.6(b) and (c), messages 
displayed in a common space may be cancelable automatically or by the 
driver.
    (b) Telltales for high beams, turn signal, low tire pressure, and 
passenger air bag off, and telltales for which the color red is 
required in table 1 to Sec.  571.101 must not be cancelable while the 
underlying condition for their activation exists.
    (c) Telltales for the seat belts must not be cancellable by the 
driver before the minimum durations are satisfied but may be 
cancellable automatically as specified in FMVSS No. 208.
* * * * *

[[Page 61737]]

Table 1 to Sec.  571.101 Controls, Telltales, and Indicators With 
Illumination or Color Requirements \1\
[GRAPHIC] [TIFF OMITTED] TP07SE23.006

[[Page 61738]]

[GRAPHIC] [TIFF OMITTED] TP07SE23.007

[[Page 61739]]

[GRAPHIC] [TIFF OMITTED] TP07SE23.008

[[Page 61740]]

[GRAPHIC] [TIFF OMITTED] TP07SE23.009

    Notes:
    \1\ An identifier is shown in this table if it is required for a 
control for which an illumination requirement exists or if it is 
used for a telltale for which a color requirement exists. If a line 
appears in column 2 and column 3, the control, telltale, or 
indicator is required to be identified, however the form of the 
identification is the manufacturer's option. Telltales are not 
considered to have an illumination requirement, because by 
definition the telltale must light when the condition for its 
activation exists.
    \2\ Additional requirements in FMVSS 108.
    \3\ Framed areas of the symbol may be solid; solid areas may be 
framed.
    \4\ Blue may be blue-green. Red may be red-orange.
    \5\ Symbols employing four lines instead of five may also be 
used.
    \6\ The pair of arrows is a single symbol. When the controls or 
telltales for left and right turn operate independently, however, 
the two arrows may be considered separate symbols and be spaced 
accordingly.
    \7\ Not required when arrows of turn signal telltales that 
otherwise operate independently flash simultaneously as hazard 
warning telltale.
    \8\ Separate identification is not required if function is 
combined with master lighting switch.
    \9\ Refer to FMVSS 105 or FMVSS 135, as appropriate, for 
additional specific requirements for brake telltale labeling and 
color. If a single telltale is used to indicate more than one brake 
system condition, the brake system malfunction identifier must be 
used.
    \10\ Requirement effective September 1, 2011.
    \11\ A manufacturer may use this telltale in flashing mode to 
indicate ESC operation.
    \12\ This symbol may also be used to indicate the malfunction of 
related systems/functions, including traction control, trailer 
stability assist, comer brake control, and other similar functions 
that use throttle and/or individual wheel torque control to operate 
and share common components with ESC.
    \13\ Combination of the engine oil pressure symbol and the 
engine coolant temperature symbol in a single telltale is permitted.
    \14\ Use when engine control is separate from the key locking 
system.
    \15\ If the speedometer is graduated in both miles per hour and 
in kilometers per hour, the scales must be identified ``MPH'' and 
``km/h'', respectively, in any combination of upper- and lowercase 
letters.
    \16\ The letters `P', `R', `N', and `D' are considered separate 
identifiers for the individual gear positions. Their locations 
within the vehicle, and with respect to each other, are governed by 
FMVSS 102. The letter `D' may be replaced by another alphanumeric 
character or symbol chosen by the manufacturer.
    \17\ Required only for FMVSS 138 compliant vehicles.

[[Page 61741]]

    \18\ Alternatively, either low tire pressure telltale may be 
used to indicate a TPMS malfunction. See FMVSS 138.
    \19\ Required only for vehicles manufactured on or after 
September 1, 2007.
    \20\ A symbol may be used at the manufacturer's option as 
provided in FMVSS No. 208 S7.5.
    \21\ These are the colors for the symbols if symbols are chosen. 
If a symbol is used to indicate to the driver how many or which rear 
seat belts are in use, the color of the illuminated symbol must be 
green. If symbols are used to indicate to the driver how many or 
which rear seat belts are not in use the color of the illuminated 
symbol must be red. See FMVSS 208 S7.5(c)(1).

Table 2 to Sec.  571.101 Identifiers for Controls, Telltales and 
Indicators With No Color or Illumination Requirements
[GRAPHIC] [TIFF OMITTED] TP07SE23.010

BILLING CODE 4910-59-C
    Notes:
    1. Use when engine control is separate from the key locking 
system.
    2. Any combination of upper- or lowercase letters may be used.
    3. Framed areas may be filled.
    4. If a line appears in Column 2 and Column 3, the Control, 
Telltale or Indicator is required to be identified, however the form 
of the identification is the manufacturer's option.
    5. Separate identification not required if function is combined 
with Master Lighting Switch.
0
3. Amend Sec.  571.208 by:
0
a. Adding paragraphs S4.1.5.7, S4.1.5.7.1, S4.1.5.8, S4.1.5.8.1, 
S4.2.8, S4.2.8.1, S4.2.9, S4.2.9.1, S4.4.3.4, S4.4.3.4.1, S4.4.3.5, 
S4.4.3.5.1, and S4.5.1.(f)(3);
0
b. Revising paragraph S4.5.3.3(b); and
0
c. Adding paragraph S7.5.
    The revisions and additions read as follows:

Sec.  571.208  Standard No. 208; Occupant crash protection.

* * * * *
    S4.1.5.7. Front seat belt warnings for passenger cars manufactured 
on or after [insert date the first September 1 that is one year after 
the date of publication of a final rule].
    S4.1.5.7.1 Any front outboard designated seating position and any 
inboard designated seating position for which a seat belt warning is 
specified in S4.1.5.6 shall comply with S7.5.
    S4.1.5.8. Rear seat belt warnings for passenger cars manufactured 
on or after [insert date the first September 1 that is two years after 
the date of publication of a final rule].
    S4.1.5.8.1. All rear designated seating positions, except in law 
enforcement vehicles, shall comply with S7.5.
* * * * *
    S4.2.8 Front seat belt warnings for trucks and multipurpose 
passenger

[[Page 61742]]

vehicles manufactured on or after [insert date the first September 1 
that is one year after the date of publication of a final rule] with a 
GVWR of 4,536 kg (10,00 lb) or less.
    S4.2.8.1. All front outboard designated seating positions certified 
to a compliance option requiring a seat belt shall comply with S7.5.
    S4.2.9 Rear seat belt warnings for trucks and multipurpose 
passenger vehicles manufactured on or after [insert date the first 
September 1 that is two years after the date of publication of a final 
rule] with a GVWR of 4,536 kg (10,00 lb) or less.
    S4.2.9.1. All rear designated seating positions certified to a 
compliance option requiring a seat belt, except law enforcement 
vehicles, shall comply with S7.5.
* * * * *
    S4.4.3.4 Front seat belt warnings for buses manufactured on or 
after [insert date the first September 1 that is one year after the 
date of publication of a final rule] with a GVWR of 4,536 kg (10,000 
lb) or less.
    S4.4.3.4.1 All front outboard designated seating positions shall 
comply with S7.5.
    S4.4.3.5 Rear seat belt warnings for buses manufactured on or after 
[insert date the first September 1 that is two years after the date of 
publication of a final rule] with a GVWR of 4,536 kg (10,000 lb) or 
less.
    S4.4.3.5.1 All rear designated seating positions certified to a 
compliance option requiring a seat belt, except for school buses and 
law enforcement vehicles, shall comply with S7.5.
* * * * *
    S4.5.1 Labeling and owner's manual information.
* * * * *
    (f) * * *
    (3) The owner's manual (which includes information provided by the 
vehicle manufacturer to the consumer, whether in digital or printed 
form) for any vehicle equipped with a seat belt warning system must 
include an accurate description of the system features and warning 
signals, including the location and format of the visual warnings, in 
an easily understandable format. The description shall include 
information on when the different features of the warning system will 
activate and how to interpret the visual warnings. For vehicles with 
any rear designated seating position that is a readily removable seat 
(a seat designed to be easily removed and replaced by means installed 
by the manufacturer for that purpose) equipped with manual electrical 
connections that are utilized by the rear seat belt warning system, the 
owner's manual (which includes information provided by the vehicle 
manufacturer to the consumer, whether in digital or printed form) must 
include a description of the purpose of the connection, instructions on 
how to achieve a proper connection in an easily understandable format, 
and a description of how not achieving a proper connection may affect 
the proper functioning of the system.
* * * * *
    S4.5.3.3 An automatic seat belt furnished pursuant to S4.5.3 shall:
* * * * *
    (b) Conform to the seat belt warning system requirements of S7.5.
* * * * *
    S7.5 Seat belt warning systems for front outboard seat belt 
assemblies in vehicles manufactured on or after [insert date the first 
September 1 that is one year after the date of publication of a final 
rule] provided in accordance with the requirements of S4.1.5.7, S4.2.8, 
S4.4.3.4, and S4.5.3.3, and rear seat belt assemblies in vehicle 
manufactured on or after [insert date the first September 1 that is two 
years after the date of publication of a final rule] provided in 
accordance with the requirements of S4.1.5.8, S4.2.9, S4.4.3.5, and 
S4.5.3.3.
    (a) Definitions for S7.5. (1) A manual seat belt is not in use when 
the seat belt latch mechanism is not fastened. A seat belt is in use 
when the seat belt latch mechanism is fastened. An automatic seat belt 
is not in use when the seat belt latch mechanism is not fastened or, if 
the automatic belt is non-detachable, the emergency release mechanism 
is in the released position. If the automatic seat belt is motorized, 
whether the seat belt is in use is determined when the seat belt 
webbing is in its locked protective mode at the anchorage point.
    (2) A front outboard passenger seating position is occupied when an 
occupant or dummy that weighs 46.7 kg (103 lb) or greater and is 139.7 
cm (55 inches) tall or taller is seated in the seat.
    (3) A rear seating position is occupied when an occupant or dummy 
that weighs 21 kg (46.5 lb) or greater and is 114 cm (45 inches) tall 
or taller is seated in the seat.
    (4) A warning cycle for an intermittent audible warning consists of 
period(s) when the warning is active at the chime frequency or 
continuously, and of inactive period(s). A warning cycle begins with an 
active period and is 30 seconds in duration.
    (5) Chime frequency means the repetition rate for an intermittent 
audible warning when the warning is active.
    (6) Duty cycle means the total amount of time an intermittent 
audible warning is active during a warning cycle at the chime frequency 
or continuously, divided by the total warning cycle duration (30 
seconds).
    (b) Front outboard seat belt warning system. For vehicles subject 
to this requirement, a driver's designated seating position and any 
front outboard passenger designating seating position must be equipped 
with an audio-visual seat belt warning meeting the requirements of 
S7.5(b)(1) through (5) when tested in accordance with S7.5(d).
    (1) Activation and duration--(i) Start of trip warning. An audio-
visual warning must activate when the ignition switch is placed in the 
``on'' or ``start'' position if the seat is occupied and the seat belt 
is not in use. The audio-visual warning must continue until the seat 
belt that triggered the warning is in use. The audio-visual warning is 
otherwise not permitted to activate except to comply with 
S7.5(b)(1)(ii).
    (ii) Change-of-status warning. An audio-visual warning must 
activate when the ignition switch is in the ``on'' or ``start'' 
position, the vehicle is in forward or reverse drive mode, and the 
status of the seat belt changes from in use to not in use, unless a 
front door on the same side of the vehicle as the seat belt triggering 
the warning is open, in which case a warning is not required and the 
system may consider this as a new trip with respect to that seat belt 
and reset the warning system. The audio-visual warning must continue 
until the seat belt that triggered the warning is in use.
    (2) Visual warning. (i) If there is a driver's designated seating 
position, the visual warning for the driver's seat belt must be visible 
from the driver's seat and the visual warning for the front outboard 
passenger seat belt must be visible from the driver's seat and the 
front outboard passenger seat.
    (ii) If there is not a driver's designated seating position, the 
visual warning for each outboard passenger designated seating position 
must be visible from each outboard passenger designated seating 
position.
    (iii) The visual warning may be continuous or intermittent and must 
display the identifying symbol or the words specified in table 2 of 
FMVSS 101.
    (iv) For telltales associated with multiple front outboard seats, 
the seat with which each telltale is associated must be clearly 
recognizable to a driver and to any front outboard passenger.

[[Page 61743]]

    (3) Audible warning. The audible warning may be continuous or 
intermittent. If intermittent, the audible warning when active must be 
continuous or have a chime frequency of at least 0.5 Hz and a duty 
cycle of at least 0.2. The same audible warning may be used for all 
seats.
    (4) Cancellation. The warning must not be able to be canceled or 
deactivated.
    (5) Override. The warning must not be overridden by other warnings.
    (c) Rear passenger seat belt warning system. For vehicles subject 
to this requirement, all rear designated seating positions must be 
equipped with a warning system that conforms to the requirements of 
S7.5(c)(1) through (6) when tested in accordance with S7.5(d).
    (1) Activation and duration--(i) Start of trip warning. A visual 
warning must activate when the ignition switch is placed in the ``on'' 
or ``start'' position and last for at least 60 seconds, except for 
systems certified to S7.5(c)(2)(i)(B) when there are no occupied rear 
seats with a seat belt that is not in use.
    (ii) Change-of-status warning. An audio-visual warning must 
activate when the ignition switch is in the ``on'' or ``start'' 
position, the vehicle is in forward or reverse drive mode, and the 
status of the seat belt changes from in use to not in use, unless any 
rear door is open, in which case a change-of-status warning is not 
required and the system may consider this situation as a new trip with 
respect to that seat belt and reset the warning system. The audio-
visual warning must last for at least 30 seconds or until the seat belt 
that triggered the warning is in use.
    (2) Visual warning. (i) The visual warning may be continuous or 
intermittent and must consist of symbols or text visible from the 
driver's seat indicating:
    (A) How many or which rear seat belts are in use;
    (B) For the occupied rear seats, how many or which rear seat belts 
are not in use;
    (C) For the occupied rear seats, how many or which rear seat belts 
are in use and how many or which rear seat belts are not in use; or
    (D) (For the change-of-status warning only) that a seating position 
experienced a seat belt change-of-status from in use to not in use.
    (ii) The warning must not indicate a seat belt is not in use for an 
unoccupied seat.
    (iii) If symbols are used to indicate to the driver how many or 
which rear seat belts are in use, the color of the illuminated symbols 
must be green. If symbols are used to indicate to the driver how many 
or which rear seat belts are not in use, the color of the illuminated 
symbols must be red.
    (iv) If text is used to indicate to the driver how many or which 
rear seat belts are in use or not in use, the text must contain the 
words ``rear belt(s) in use'' or ``rear belt(s) not in use.''
    (v) The visual warning must not be overridden by other visual 
warnings.
    (3) Audible warning. The audible warning may be continuous or 
intermittent. If intermittent, inactive periods longer than 3 seconds 
will not be counted toward the total duration of the audible warning. 
The same audible warning may be used for all rear seats, and the same 
audible warning may be used for the rear as for the front.
    (4) Cancellation. The warning must not be able to be canceled or 
deactivated.
    (5) Override. The warning must not be overridden by other warnings.
    (6) Seat electrical connection requirements. Any rear designated 
seating position consisting of a readily removable seat (a seat 
designed to be easily removed and replaced by means installed by the 
manufacturer for that purpose) that is equipped with electrical 
connections utilized by the rear seat belt warning system must either--
    (i) Automatically connect the electrical connections when the seat 
is put in place; or
    (ii) If a manual electrical connection is required, the connectors 
must be readily accessible.
    (7) Electrical connection warning signal. Vehicles that provide a 
visual warning according to S7.5(c)(2)(i)(B) and are equipped with any 
readily removable rear seat(s) (a seat designed to be easily removed 
and replaced by means installed by the manufacturer for that purpose) 
must, when the ignition switch is placed in the ``on'' or ``start'' 
position, provide an intermittent visual warning visible from the 
driver's seat if a seat has been installed and a proper electrical 
connection has not been made. The visual warning must remain active 
until all the rear seat electrical connections are properly made.
    (d) Test procedures--(1) In general. (i) If testing with any 
designated seating position occupied, use the seating procedures in 
S7.5(d)(2) for front designated seating positions and the seating 
procedures in S7.5(d)(3) for rear designated seating positions.
    (ii) Place the ignition switch in the ``on'' or ``start'' position 
and verify that the seat belt warnings function as specified in S7.5(b) 
and S7.5(c), for any combination of seat belt use or seat occupancy at 
any designated seating position(s).
    (2) Seating procedures for front designated seating positions--(i) 
Anthropomorphic test devices used for testing. The anthropomorphic test 
device (test dummy) is any of the anthropomorphic test devices 
specified in part 572 that meet the criteria specified in S7.5(a)(2).
    (ii) Seating procedure. (A) With the seat back in the 
manufacturer's nominal design riding position, any other seat 
adjustments in any position, and any adjustable seat belt anchorages in 
any position, seat the test dummy such that the midsagittal plane of 
the dummy is vertical and within  10 mm of the seat 
centerline, with the torso and pelvis in contact with the seat back.
    (B) At the option of the manufacturer (irrevocably selected prior 
to or at the time of certification of the vehicle), instead of using 
test dummies, a human being (dressed in a cotton T-shirt, full length 
cotton trousers, and sneakers) may be used whose weight and height 
(including this clothing) meet the criteria specified in S7.5(a)(2). 
The person should be seated in order to match, to the extent possible, 
the final physical position specified in S7.5(d)(2)(ii)(A).
    (3) Seating procedures for rear designated seating positions--(i) 
Anthropomorphic test devices used for testing. The anthropomorphic test 
device is any of the anthropomorphic test devices specified in part 572 
that meet the criteria specified in S7.5(a)(3).
    (ii) Seating procedure. (A) With the seat back in the 
manufacturer's nominal design riding position, any other seat 
adjustments in any position, and any adjustable anchorages in any 
position, seat the test dummy such that the midsagittal plane of the 
dummy is vertical and within  10 mm of the seat centerline, 
with the torso and pelvis in contact with the seat back; or
    (B) At the option of the manufacturer (irrevocably selected prior 
to or at the time of certification of the vehicle), instead of using 
test dummies, a human being (dressed in a cotton T-shirt, full length 
cotton trousers, and sneakers) may be used whose weight and height 
(including this clothing) meet the criteria specified in S7.5(a)(3). 
The person should be seated in order to match, to the extent possible, 
the final physical position specified in S7.5(d)(3)(ii)(A).
* * * * *

    Issued under authority delegated in 49 CFR 1.95, 501.4, and 
501.5.
Ann Carlson,
Acting Administrator.
[FR Doc. 2023-18413 Filed 9-6-23; 8:45 am]
BILLING CODE 4910-59-P