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Proposed Rule2023-18413

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

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Published

September 7, 2023

Issuing agencies

Transportation DepartmentNational Highway Traffic Safety Administration

Abstract

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.

Full Text

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[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 [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[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 <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the online
instructions for submitting comments.
Alternatively, you can file comments using the following methods:
<bullet> 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.
<bullet> Hand Delivery or Courier: West Building Ground Floor, Room
W12-140, 1200 New Jersey Avenue SE, between 9 a.m. and 5 p.m. ET,
Monday through Friday, except Federal holidays. To be sure someone is
there to help you, please call (202) 366-9826 before coming.
<bullet> 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 <a href="http://www.reginfo.gov/public/do/PRAMain">www.reginfo.gov/public/do/PRAMain</a>. 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 <a href="https://www.regulations.gov">https://www.regulations.gov</a>, 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 <a href="https://www.regulations.gov">https://www.regulations.gov</a>. 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: <a href="/cdn-cgi/l/email-protection#137072617f723d6166607b53777c673d747c65">[email&#160;protected]</a>; Facsimile: (202) 493-2739. For
legal issues, you may contact Mr. John Piazza, Office of Chief Counsel,
Telephone: (202) 366-2992; Email: <a href="/cdn-cgi/l/email-protection#743e1b1c1a5a241d150e0e1534101b005a131b02">[email&#160;protected]</a>; 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 <a href="https://www.transportation.gov/briefing-room/nhtsa-estimates-2022-show-roadway-fatalities-remain-flat-after-two-years-dramatic">https://www.transportation.gov/briefing-room/nhtsa-estimates-2022-show-roadway-fatalities-remain-flat-after-two-years-dramatic</a>. 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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[[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.
<bullet> 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.
<bullet> 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.
<bullet> 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.
<bullet> 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.
<bullet> 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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<bullet> 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.
<bullet> 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

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

Table 2--Estimated Annual Benefits--Equivalent Lives Saved--Positive-
Only SBWS (Rear Seats)
------------------------------------------------------------------------
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]
----------------------------------------------------------------------------------------------------------------
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 <a href="https://www.transportation.gov/briefing-room/nhtsa-estimates-2022-show-roadway-fatalities-remain-flat-after-two-years-dramatic">https://www.transportation.gov/briefing-room/nhtsa-estimates-2022-show-roadway-fatalities-remain-flat-after-two-years-dramatic</a>. 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\ <a href="https://www.transportation.gov/sites/dot.gov/files/2022-02/USDOT-National-Roadway-Safety-Strategy.pdf">https://www.transportation.gov/sites/dot.gov/files/2022-02/USDOT-National-Roadway-Safety-Strategy.pdf</a>.
---------------------------------------------------------------------------

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. <a href="http://meps.ahrq.gov/mepsweb/data_files/publications/st62/stat62.pdf">http://meps.ahrq.gov/mepsweb/data_files/publications/st62/stat62.pdf</a>. 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 <a href="http://isearch.nhtsa.gov/search.htm">http://isearch.nhtsa.gov/search.htm</a>.
---------------------------------------------------------------------------

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

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

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

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

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

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 <a href="http://www.regulations.gov">www.regulations.gov</a> (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, <a href="https://www.nhtsa.gov/FARS">https://www.nhtsa.gov/FARS</a>. 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.
<bullet> 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.
<bullet> 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]]

<bullet> 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.
<bullet> 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:
<bullet> 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.
<bullet> 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).
<bullet> 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.
<bullet> 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.
---------------------------------------------------------------------------

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

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

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

\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\
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\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 <a href="https://www.nhtsa.gov/equipment/car-seats-and-booster-seats">https://www.nhtsa.gov/equipment/car-seats-and-booster-seats</a> (last accessed
Apr. 7, 2022).
\133\ See <a href="https://www.healthychildren.org/English/safety-prevention/on-the-go/Pages/Car-Safety-Seats-Product-Listing.aspx">https://www.healthychildren.org/English/safety-prevention/on-the-go/Pages/Car-Safety-Seats-Product-Listing.aspx</a>.
---------------------------------------------------------------------------

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\ <a href="https://www.nhtsa.gov/road-safety/child-safety">https://www.nhtsa.gov/road-safety/child-safety</a>.
---------------------------------------------------------------------------

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\
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\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.
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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.
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\151\ Section 8.4.2.2.1.
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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.
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\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.
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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\
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\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.
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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.
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\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.
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The proposal differs from R16 and Euro NCAP in a few ways:
<bullet> 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.
<bullet> 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)
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\156\ Section 8.4.2.4.1.
\157\ Section 3.4.3.2.3.
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<bullet> 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\
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\158\ DOT 2007 Acceptability Study, supra n.78.
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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\
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\159\ Section 8.4.2.1.1.
\160\ Section 3.4.1.1.
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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\
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\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.
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Figure 2--Seat Belt Telltale From FMVSS No. 101
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The rear reminder requirements in ECE R16 m

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