Document ID: NHTSA-2020-0067-0001
Agency: nhtsa
Document Type: Proposed Rule
Title: Standard Reference Test Tire
Posted Date: 2021-08-05T04:00Z

[Federal Register Volume 86, Number 148 (Thursday, August 5, 2021)]
[Proposed Rules]
[Pages 42762-42775]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-15361]

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 571 and 575

[Docket No. NHTSA-2020-0067]
RIN 2127-AL92

Standard Reference Test Tire

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

[[Page 42763]]

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes amendments to several Federal motor 
vehicle safety standards and consumer information regulations to update 
the standard reference test tire (SRTT) used therein. The SRTT is used 
in those standards and regulations as a baseline tire to rate tire 
treadwear, define snow tires based on traction performance, and 
evaluate pavement surface friction. This proposed rule is necessary 
because the only manufacturer of the currently referenced SRTT ceased 
production of the tire. Referencing a new SRTT ensures the availability 
of a test tire for testing purposes.

DATES: Submit comments on or before September 7, 2021.

ADDRESSES: You may submit comments electronically to the docket 
identified in the heading of this document by visiting the following 
website:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the online instructions for submitting 
comments.

Alternatively, you can file comments using the following methods:

     Mail: Docket Management Facility: U.S. Department of 
Transportation, 1200 New Jersey Avenue SE, West Building Ground Floor, 
Room W12-140, Washington, DC 20590-0001.
     Hand Delivery or Courier: West Building Ground Floor, Room 
W12-140, 1200 New Jersey Avenue SE, between 9 a.m. and 5 p.m. ET, 
Monday through Friday, except Federal holidays. To be sure someone is 
there to help you, please call (202) 366-9826 before coming.
     Fax: (202) 493-2251.
    Regardless of how you submit your comments, you should mention the 
docket number identified in the heading of this document.
    Instructions: For detailed instructions on submitting comments and 
additional information on the rulemaking process, see the Public 
Participation heading of the Supplementary Information section of this 
document. Note that all comments received will be posted without change 
to http://www.regulations.gov, including any personal information 
provided. Please see the Privacy Act heading below.
    Privacy Act: In accordance with 5 U.S.C. 553(c), DOT solicits 
comments from the public to better inform its rulemaking process. DOT 
posts these comments, without edit, to www.regulations.gov, as 
described in the system of records notice, DOT/ALL-14 FDMS, accessible 
through www.dot.gov/privacy. In order to facilitate comment tracking 
and response, we encourage commenters to provide their name, or the 
name of their organization; however, submission of names is completely 
optional. Whether or not commenters identify themselves, all timely 
comments will be fully considered. If you wish to provide comments 
containing proprietary or confidential information, please contact the 
agency for alternate submission instructions.
    Docket: For access to the docket to read background documents or 
comments received, go to http://www.regulations.gov. Follow the online 
instructions for accessing the dockets.

FOR FURTHER INFORMATION CONTACT: You may contact Hisham Mohamed, Office 
of Crash Avoidance Standards, by telephone at (202) 366-0307 or David 
Jasinski, Office of the Chief Counsel, by telephone at (202) 366-2992. 
The mailing address of both of these officials is: National Highway 
Traffic Safety Administration, 1200 New Jersey Avenue SE, Washington, 
DC 20590.

SUPPLEMENTARY INFORMATION: 

I. Background

    This rulemaking addresses the standard reference test tire (SRTT) 
manufactured according to specifications set forth in an ASTM 
International standard, E1136, ``Standard Specification for P195/75R14 
Radial Standard Reference Test Tire'' (14-inch SRTT). The 14-inch SRTT 
is a size P195/75R14 all-season steel-belted radial tire. The 
dimensions, weight, materials, and other physical properties of the 
tire are specified in E1136. The tire is not intended for general use, 
but as the name indicates, is used for testing.
    The 14-inch SRTT was first introduced in the 1980s. The 14-inch 
SRTT was manufactured by one company, Michelin North America, Inc 
(Michelin) and was sold under its Uniroyal brand. NHTSA uses the 14-
inch SRTT to evaluate tire treadwear performance \1\ by comparing a 
candidate tire's performance to the performance of the SRTT in a 
particular performance test. NHTSA also uses the 14-inch SRTT to 
evaluate test surface friction \2\ for safety standards relating to 
braking because the narrow specifications for the tire (size, component 
materials, etc.) ensure consistent, repeatable performance.
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    \1\ 49 CFR 575.104.
    \2\ 49 CFR 571.105, 571.121, 571.122, 571.126, 571.135, 571.136, 
571.139, 571.500.
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    NHTSA first incorporated the 14-inch SRTT into the Federal Motor 
Vehicle Safety Standards (FMVSSs) in a 1995 rule adopting FMVSS No. 
135, the light vehicle braking standard.\3\ Previously, NHTSA had used 
skid number to define the road test surface in the light vehicle 
braking test. Testing a surface to determine skid number involved using 
a locked wheel. However, modern anti-lock brake systems (ABS) are 
designed to achieve maximum friction prior to a wheel becoming locked 
and the tire skidding. An anti-lock brake system prevents wheel lockup 
by modulating a vehicle's brakes at a point just before the wheels 
would lock up. Consequently, in the 1995 final rule, NHTSA adopted ASTM 
method E1337, ``Standard Test Method for Determining Longitudinal Peak 
Braking Coefficient (PBC) of Paved Surfaces Using Standard Reference 
Test Tire,'' as the means for evaluating test surfaces.\4\ ASTM E1337 
measures the peak braking force prior to wheel lockup, which 
corresponds to the behavior of an anti-lock brake system. ASTM E1337 
specifies the use of the E1136 SRTT in order to ensure that variability 
in tire size, material, or construction does not affect the evaluation 
of test surfaces.
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    \3\ 60 FR 6411, 6415-17 (Feb. 2, 1995).
    \4\ Another reason for adopting the peak braking force related 
to the variability associated with determining skid number. That 
matter was discussed in more detail in NHTSA's earlier proposals to 
require heavy vehicles to be equipped with anti-lock brake systems. 
See 49 FR 20465 (May 14, 1984); 49 FR 28962 (July 17, 1984).
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    Over time, the evaluation of a test surface using the ASTM E1337 
test method and the E1136 SRTT was incorporated into the heavy vehicle 
braking standards (FMVSS Nos. 105 and 121), the light and heavy vehicle 
electronic stability control standards (FMVSS Nos. 126 and 136), the 
motorcycle braking standard (FMVSS No. 122), and the low-speed vehicle 
standard (FMVSS No. 500).\5\
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    \5\ ASTM E1337 is also incorporated by reference into 49 CFR 
575.106, which are the provisions related to a new tire consumer 
information program. However, the test procedures in 49 CFR 575.106 
are not currently used pending publication of a proposed and final 
rule establishing the remaining aspects of the consumer information 
program. See 75 FR 15893 (Mar. 30, 2010). Therefore, this proposal 
does not address 49 CFR 575.106. In a proposal implementing the 
remaining aspects of that tire consumer information program, NHTSA 
would address the issues discussed in this proposal.
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    The use of the 14-inch SRTT is also incorporated into the 
definition of a ``snow tire'' in FMVSS No. 139. Specifically, a ``snow 
tire'' is defined as a tire that attains a traction index greater than 
or equal to 110 compared to the 14-inch SRTT when using the ASTM F1805 
snow traction test. The ASTM F1805 snow traction test measures the 
driving traction of tires while traveling in a

[[Page 42764]]

straight line on snow- and ice-covered surfaces. Tires that meet the 
definition of ``snow tires'' are subject to less stringent performance 
test requirements compared to other tires subject to FMVSS No. 139.\6\
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    \6\ See 71 FR 877, 880 (Jan. 6, 2006).
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    The SRTT is also used as part of the Uniform Tire Quality Grading 
Standards (UTQGS), an information program to assist consumers in making 
informed decisions when purchasing tires. The UTQGS apply to passenger 
car tires and require motor vehicle and tire manufacturers and tire 
brand name owners to provide consumers with information about their 
tires' relative performance regarding treadwear, traction, and 
temperature resistance.
    The 14-inch SRTT is used as part of the determination of a tire's 
UTQG treadwear rating. As part of the UTQG test procedures, treadwear 
is measured by running the tires being tested (called candidate tires) 
in convoys over a 400-mile course of public roads near San Angelo, 
Texas. The performance of tires over this course can change daily due 
to variability in the road surface, temperature, humidity, and 
precipitation. To compensate for changes in condition of the test 
course, candidate tires are tested concurrently with course monitoring 
tires (CMTs).
    NHTSA has used the 14-inch SRTT as the exclusive CMT since 1991. 
CMTs must be not more than one year old at the time of commencement of 
the test and must be used within two months from being removed from 
storage in order to prevent variability resulting from aging of the 
CMT. The performance of the CMT is used to determine the base course 
wear rate (BCWR) by running four-vehicle convoys equipped with 16 CMTs 
for 6,400 miles over the test course four times per year. \7\ The wear 
rate of the CMT over the prior four quarterly CMT test runs are 
averaged to calculate the BCWR, which is published in Docket No. NHTSA-
2001-9395. The BCWR is used to determine a course severity adjustment 
factor, which is applied to the comparison between the candidate tires 
and CMTs to determine a tire's rating.
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    \7\ See 65 FR 33481 (May 24, 2000).
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II. Proposal To Replace 14-Inch SRTT With 16-Inch SRTT

    This proposal would amend NHTSA's safety standards and regulations 
to no longer reference the 14-inch SRTT. Because of technological 
advancements in the development of tires and the general trend of 
increasing rim diameter sizes since the 1980s, the size and materials 
of the 14-inch SRTT are no longer representative of modern tires sold 
in the U.S. Further, Michelin has ceased production of the 14-inch SRTT 
because it has become difficult for Michelin to obtain the materials 
necessary to manufacture the SRTT.\8\ Thus, NHTSA seeks to reference a 
different standard reference test tire in the agency's safety standards 
and regulations and to transition seamlessly to the new tire in the 
agency's compliance and consumer information test programs.
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    \8\ See ``Discontinued Tire Will Lead to ASTM Standard Changes'' 
(July 30, 2015), available at https://www.astm.org/cms/drupal-7.51/newsroom/discontinued-tire-will-lead-astm-standard-changes (last 
accessed April 13, 2021).
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    ASTM International has developed an updated specification for an 
SRTT designated F2493 (16-inch SRTT). The 16-inch SRTT is size P225/
60R16. The 16-inch SRTT is considered to be more representative of 
current tires because of its larger size and new material and design 
features that lead to traction that is more typical of modern passenger 
car tires.\9\ To the best of NHTSA's knowledge, the 16-inch SRTT is 
manufactured only by Michelin and sold under its Uniroyal brand.
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    \9\ See ``New ASTM Specification Presents Requirements for 
Standard Reference Test Tire'' (April 1, 2007), available at https://www.astm.org/cms/drupal-7.51/newsroom/new-astm-specification-presents-requirements-standard-reference-test-tire (last accessed 
April 13, 2021).
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    To reference an SRTT that is more representative of tires on the 
road today, and in consideration of Michelin's decision to cease 
production of the 14-inch SRTT, NHTSA has determined that replacing the 
14-inch SRTT in its regulations is warranted. The only suitable 
replacement for the 14-inch SRTT that has been suggested to NHTSA is 
the 16-inch SRTT. However, because the 16-inch SRTT is a larger size 
and uses more modern design and materials, it is likely that the 16-
inch SRTT will not perform identically to the 14-inch SRTT. Therefore, 
NHTSA has been cooperating with Transport Canada, Natural Resources 
Canada, representatives of ASTM International committees F09 on tires 
and E17 on vehicle-pavement systems, the U.S. Tire Manufacturers 
Association (including Michelin, currently the sole manufacturer of 
SRTTs), and the Rubber Association of Canada to conduct testing to 
determine the consequences of replacing the 14-inch SRTT with the 16-
inch SRTT. The results of the testing by these entities, in addition to 
NHTSA's own testing, have substantially contributed to this proposal to 
replace the 14-inch SRTT with the 16-inch SRTT.\10\
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    \10\ See Docket No. NHTSA-2020-0067.
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A. Proposed FMVSS Amendments

1. Surface Friction Measurement
    As discussed above, other than for defining a ``snow tire,'' NHTSA 
uses the SRTT in the FMVSSs to define the surface coefficient of 
friction for the test surface for braking and electronic stability 
control (ESC) standards. The friction of the test surface is measured 
by the peak braking force prior to wheel lockup, which is referred to 
as a peak friction coefficient (PFC) or peak braking coefficient (PBC). 
For the purpose of this preamble, NHTSA uses the term peak friction 
coefficient or PFC, but the terms are used interchangeably in the 
FMVSS.
    In the FMVSS, the peak friction coefficient of a surface is 
determined using the 1990 version of ASTM E1337 test method. The ASTM 
E1337 test method involves mounting the SRTT to a test trailer, 
bringing the trailer to a test speed of 40 mph (64 km/h), and applying 
the brake to produce the maximum braking force prior to wheel lockup.
    When NHTSA was informed that production of the 14-inch SRTT was to 
be discontinued, NHTSA evaluated the 16-inch SRTT to determine whether 
it would be a suitable replacement. NHTSA carefully considered the 
effect of the 16-inch SRTT on the determination of PFC. NHTSA was 
concerned that the use of the 16-inch SRTT without further changes to 
the FMVSSs would increase the stringency of the braking and ESC FMVSSs. 
The reason for this was that the different materials used in the 16-
inch SRTT and the increased size of the tire would result in the 16-
inch SRTT having better traction performance than the 14-inch SRTT. If 
the 16-inch SRTT has improved traction performance relative to the 14-
inch SRTT, then the same surface would have a higher PFC when tested 
with the 16-inch SRTT. Alternatively stated, obtaining an identical PFC 
value using the 16-inch SRTT would require a road surface with lower 
friction. Testing braking systems using stopping distance on road 
surfaces with lower friction would require improved braking performance 
to stop in the same distance, which is not an outcome intended by this 
rulemaking. Consequently, NHTSA sought a conversion factor to evaluate 
PFC of a test surface using the 16-inch SRTT without altering the 
severity of any braking or ESC FMVSSs.

[[Page 42765]]

    Initial testing confirmed the assumption that using the 16-inch 
SRTT resulted in a test surface having a higher PFC than when evaluated 
using the 14-inch SRTT. Transportation Research Center, Inc. (TRC) 
conducted initial testing in support of the ASTM committee evaluating 
this issue (the E17.21 committee).\11\ Testing was conducted on 15 
different surfaces of varying friction. The evaluation of a dry test 
surface (e.g., 0.9 PFC using the 14-inch SRTT) using the 16-inch SRTT 
resulted in a PFC over 15 percent higher than the PFC derived using the 
14-inch SRTT. However, testing on a low friction surface (0.5 PFC using 
the 14-inch SRTT) showed that the PFC derived using the 16-inch SRTT 
and the 14-inch SRTT was similar.
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    \11\ See docket No. NHTSA-2020-0067.
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    Because the difference in performance between the 16-inch SRTT and 
the 14-inch SRTT was not consistent for all levels of surface friction, 
something more than a simple multiplier is necessary to correlate 
performance between the two tires. ASTM International has developed 
such a formula. That formula is included in the 2019 update to ASTM 
E1337, which NHTSA is proposing to incorporate by reference into the 
FMVSSs, in place of the 1990 version of E1337 currently referenced. 
NHTSA has used the formula in the 2019 version of E1337 to derive PFC 
value for all of the FMVSSs. Those values are listed in the table 
below.
    Each value derived using the formula was rounded to the hundredths 
position, rounding up if necessary. This ensures that the updated FMVSS 
test surface PFC specification will be no more stringent as a result of 
this proposed amendment than it is now, consistent with NHTSA's intent 
in this rulemaking.

------------------------------------------------------------------------
                                       PFC value using   PFC value using
            FMVSS section               14-inch SRTT      16-inch SRTT
------------------------------------------------------------------------
FMVSS No. 105 S6.9.2(a) (high                      0.9              1.02
 friction testing)..................
FMVSS No. 105 S6.9.2(b) (low                       0.5              0.55
 friction testing)..................
FMVSS No. 121 S5.3.1.1, S5.7.1,                    0.9              1.02
 S6.1.7 (high friction testing) \12\
FMVSS No. 121 S5.3.6.1, S6.1.7 (low                0.5              0.55
 friction testing)..................
FMVSS No. 122 S6.1.1.1 (high                       0.9              1.02
 friction testing)..................
FMVSS No. 122 S6.1.1.2 (low friction            <=0.45            <=0.50
 testing)...........................
FMVSS No. 122 S6.9.7.1..............             >=0.8            >=0.90
FMVSS No. 126 S6.2.2................               0.9              1.02
FMVSS No. 135 S6.2.1, S7.4.3,                      0.9              1.02
 S7.5.2, S7.6.2, S7.7.3, S7.8.2,
 S7.9.2, S7.10.3, S7.11.3...........
FMVSS No. 136.......................               0.9              1.02
FMVSS No. 500 \13\..................               0.9              1.02
------------------------------------------------------------------------

    NHTSA commissioned confirmatory testing using the 16-inch SRTT to 
verify that the PFC values discussed above are equivalent to the PFC 
values in the FMVSSs derived using the 14-inch SRTT. NHTSA has 
contracted with TRC to conduct this testing on five different test 
surfaces (wet ceramic, wet jennite, wet asphalt, dry asphalt, and dry 
broomed concrete). These test surfaces range from high to low PFC 
values. For each test surface, 10 of each of the 14-inch SRTT and the 
16-inch SRTT were each tested 3 times with 10 stops per test, for a 
total of 300 tests for each size SRTT on each test surface. A final 
report summarizing the results has been placed in the docket identified 
at the beginning of this NPRM.
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    \12\ NHTSA is also proposing to revise Tables I, II, and IIA in 
FMVSS No. 121 to eliminate the redundant references to PFC values in 
those tables. In place of PFC values, NHTSA is proposing to include 
in Table I (Stopping Sequence) references to the sections in which 
the various procedures are set forth, which is a more helpful 
reference.
    \13\ Although FMVSS No. 500 specifies a PFC value for the test 
surface, the test surface is only used to verify the vehicle's 
maximum speed.
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2. Snow Tire Definition
    Presently, for a manufacturer to designate a tire as a ``snow 
tire,'' the tire must attain a traction index equal to or greater than 
110 compared to the 14-inch SRTT when tested using the snow traction 
test in the 2000 version of ASTM F1805. The ASTM F09 committee on tires 
commissioned a study to determine the feasibility of replacing the 14-
inch SRTT with the 16-inch SRTT in the determination of whether a tire 
meets the definition of ``snow tire.'' This study was funded by the 
United States Tire Manufacturers Association (USTMA).
    The study consisted of testing of traction during the winter test 
seasons of 2016, 2017, and 2018 to develop a method to correlate 
results of tests conducted using the 16-inch SRTT with those conducted 
using the 14-inch SRTT. ASTM International has published a technical 
report documenting this work.\14\ ASTM International determined that a 
correlation factor of 0.9876 was appropriate, meaning that a tire that 
attained a rating of 110 when tested using the 14-inch SRTT correlated 
to a rating of 111.4 or 111.5 when tested using the 16-inch SRTT, 
depending on the number of significant digits considered. Recent 
guidance issued by the USTMA, a trade association consisting of 
companies that manufacture tires in the United States, recommends a 
minimum traction index of 112 using the 16-inch SRTT.\15\ Accordingly, 
NHTSA is proposing to amend the definition of ``snow tire'' in FMVSS 
No. 139 to specify that a snow tire is a tire that attains a traction 
index of 112 when tested using the updated F1895 test method using the 
16-inch SRTT. This proposal is consistent with the guidance issued by 
USTMA, which NHTSA believes reflects a consensus within the tire 
industry on the appropriate traction index for use in determining what 
qualifies as a ``snow tire.'' NHTSA seeks comment on this proposal.
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    \14\ Available at https://www.astm.org/COMMIT/2019_04_10_E1136%20to%20F2493%20transition%20for%20ASTMF1805.pdf 
(last accessed April 13, 2021).
    \15\ See https://www.ustires.org/sites/default/files/USTMA_TISB_37_0.pdf (last accessed April 13, 2021).
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    Furthermore, after reviewing this information from the USTMA, NHTSA 
determined that additional clarification was necessary to the 
definition of a ``snow tire'' in FMVSS No. 139. The latest (2020) 
version of ASTM F1805 defines the standard test procedure for measuring 
traction on ``snow'' and ``ice'' surfaces. However, there are multiple 
surface types in both the ``snow'' and ``ice'' categories. They include 
soft pack (new) snow, medium pack snow, medium hard pack snow, hard 
pack snow, ice--wet, and ice--dry.\16\ The definition of ``snow tire'' 
in FMVSS No.

[[Page 42766]]

139 does not specify the surface type specified within ASTM F1805 for 
testing.
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    \16\ The surface types are defined in the text of ASTM F1805.
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    NHTSA interprets that the ``medium pack snow'' condition was 
intended for use by manufacturers for marketing tires as ``snow 
tires.'' NHTSA seeks comment on whether this assumption is correct. It 
is the surface type specified for severe snow tires in UNECE Regulation 
No. 117 for determining when use of the Alpine or Three-Peak Mountain 
Snowflake marking that indicates that a tire meets the requirements for 
use in severe snow conditions. Based upon the research on the SRTT, the 
2020 revision of ASTM F1805 contains a revised tractive coefficient 
range for ``medium pack snow'' using the 14-inch SRTT from 0.25-0.41 to 
0.25-0.38 and adds a tractive coefficient range for ``medium pack 
snow'' using the 16-inch SRTT of 0.23-0.38.
    Based on the research by ASTM International and USTMA's recent 
guidance, NHTSA is proposing to update the definition of a ``snow 
tire'': (1) To replace the reference to the 14-inch SRTT with the 16-
inch SRTT and to change the minimum traction index in order to meet the 
definition of a ``snow tire'' from 110 to 112 using this tire; (2) to 
specify that this traction index is obtained when tested on the 
``medium pack snow'' surface, and (3) to update the incorporation by 
reference of ASTM F1805 from the 2000 version to the 2020 version, 
which is the latest version. ASTM F1805-20 incorporates the research 
discussed above. NHTSA is not aware of other research on equivalent 
performance of the 14-inch SRTT and 16-inch SRTT on snow-covered 
surfaces other than the testing by ASTM International.

B. Proposed UTQGS Amendments

    In anticipation of Michelin's decision to cease production of the 
14-inch SRTT, NHTSA began including testing of the 16-inch SRTT as part 
of its BCWR determination. Since the second quarter of 2016, NHTSA has 
been duplicating BCWR testing using both the 14-inch SRTT and the 16-
inch SRTT. NHTSA has shared some data from this testing with its 
testing partners (named at the end of Section I of this preamble) in 
order to develop options that could be implemented once production of 
the 14-inch SRTT has ended. Four options have been considered:
    1. Use the research data to develop a correlation formula between 
the 14-inch SRTT and the 16-inch SRTT. While this would allow future 
testing and rating to be based on either SRTT, it was likely to be the 
most resource-intensive to develop and validate a formula.
    2. Establish an effective date for the 16-inch SRTT and begin 
publishing the quarterly BCWR after that date using four quarters of 
data using that tire. After two quarters of testing it was apparent 
that this was likely to result in a shift in the BCWR. However, large 
shifts in BCWR have occurred in the past, such as when repaving was 
done on portions of the route.
    3. Allow a transition period in which NHTSA would publish BCWR 
rates for both SRTTs, allowing manufacturers to choose when to shift 
within that period.
    4. Establish an effective date to begin quarterly testing with the 
16-inch SRTT, but continue to calculate the BCWR rate using the prior 
quarterly testing results used to calculate prior BCWR rates. The first 
quarter with official testing using the 16-inch SRTT CMT would result 
in a BCWR rate calculated from the average of those results and the 
results of the previous three quarters testing using the 14-inch SRTT 
CMT, the second quarter would average two quarters with the 16-inch 
SRTT CMT and 2 quarters with the 14-inch SRTT CMT, and so on.
    In 2017, Michelin informed NHTSA that the test results from the 
first two quarters of testing were within the normal variability seen 
for BCWR.\17\ Michelin believed that NHTSA could develop an entirely 
new formula for determining BCWR, but believed that such a formula may 
not be able to be developed prior to the end of production of 14-inch 
SRTT. Instead, Michelin recommended adding a new conversion factor to 
the existing formula derived from the ratio of the BCWR from the 14-
inch SRTT CMT to the BCWR of the 16-inch SRTT CMT measured over a 
specific number of quarters of testing. Michelin recommended that this 
factor be based on at least six quarters of testing, which was all the 
testing that was available at the time of Michelin's recommendation.
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    \17\ Michelin presentation; UTQG Wear Change from 14'' TO 16'' 
SRTT First Two Test Quarters. See docket No. NHTSA-2020-0067.
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    NHTSA now has 14 consecutive quarters of testing data. Table 1 
summarizes the quarterly BCWR values determined by NHTSA since the 
first quarter of 2017. As shown in Table 1, NHTSA has determined BCWR 
reference values for the 16-inch SRTT. Table 1 also shows BCWR rates 
for the 16-inch SRTT beginning in Q2 2017 after four quarters of BCWR 
values were obtained. Table 1 also shows a conversion factor based on 
the ratio of the BCWR using the 14-inch SRTT to the BCWR using the 16-
inch SRTT measured over all available quarters of testing.

                                                      Table 1--Quarterly BCWR Data Since April 2016
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                            Derived
                                                           14-inch SRTT BCWR  16-inch SRTT BCWR      Quarterly       Theoretical 16-   conversion factor
                                                                  data               data          published BCWR     inch SRTT BCWR     based on prior
                                                                                                        rate               rate           six quarters
--------------------------------------------------------------------------------------------------------------------------------------------------------
January-March 2017.......................................              8.090              5.349              9.059  .................  .................
April-June 2017..........................................              7.556              5.952              8.573  .................  .................
July-September 2017......................................              9.640              6.189              8.692  .................  .................
October-December 2017....................................              8.932              6.578              8.555              6.017  .................
January-March 2018.......................................              7.481              5.731              8.402              6.113  .................
April-June 2018..........................................              8.253              6.074              8.577              6.143              1.392
July-September 2018......................................              9.648              6.467              8.579              6.213              1.393
October-December 2018....................................              8.867              6.602              8.562              6.219              1.403
January-March 2019.......................................              6.555              5.999              8.331              6.286              1.328
April-June 2019..........................................              8.242              5.506              8.328              6.144              1.348
July-September 2019......................................              7.243              5.656              7.727              5.941              1.344
October-December 2019....................................              7.237              6.206              7.319              5.842              1.312
January-March 2020.......................................              7.695              5.259              7.604              5.657              1.301
April-June 2020..........................................              6.719              5.616              7.224              5.684              1.276

[[Page 42767]]

 
July-September 2020......................................              6.983              6.856              7.159              5.984              1.257
October-December 2020....................................              8.122              6.886              7.380              6.154              1.206
January-March 2021.......................................              7.228              4.687              7.263              6.011              1.239
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The conversion factor listed in the last column of Table 1 is 
determined by dividing the average of six quarters of BCWR testing with 
the 14-inch SRTT by the average of the same six quarters of BCWR with 
the 16-inch SRTT. The conversion factor is similar for all quarters 
currently available. NHTSA requests comments on how the new conversion 
factor should be selected from among the available quarters of data. 
For example, NHTSA could use the last six (or some other number) of 
quarters of data, or all data available to determine the conversion 
factor. NHTSA requests comments on which of these possible conversion 
factors NHTSA could use and why.
    For this NPRM, NHTSA is basing the adjustment on the average of all 
17 consecutive quarters of available data. The average BCWR wear rate 
using the 14-inch SRTT is 7.911. The average BCWR wear rate using the 
16-inch SRTT is 5.942. Dividing 7.911 by 5.977 results in a conversion 
factor of 1.324. Based upon this new conversion factor, the new formula 
for the treadwear grade, assuming the decision was to use the most 
recent quarter's conversion factor, would be: \18\
---------------------------------------------------------------------------

    \18\ The first equation definition P is set forth in 49 CFR 
57.104(e)(2)(ix)(F).
---------------------------------------------------------------------------

BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TP05AU21.038

BILLING CODE 4910-59-C
    NHTSA does not believe the calculation of projected mileage as used 
in this formula also requires adjustment, as the calculation takes into 
consideration the actual measurement of the CMT used during the test of 
the candidate tire being evaluated.
    NHTSA is also proposing to modify language in the treadwear test 
procedure in Sec.  575.104 to reference the total distance and schedule 
of events in terms of circuits completed rather than mileage. This 
proposed change is intended to allow testing to be more flexible in the 
vent of route changes or other unforeseen circumstances. With the added 
flexibility of these changes, NHTSA believes that it is preferable to 
use the actual mileage of the completed circuit in the calculation of 
the wear rate rather than the estimated 400 miles per circuit. NHTSA 
believes that this would ensure that the wear rate reflects the actual 
mileage covered if the completed 16 circuits is not exactly 6,400 
miles. NHTSA seeks comment on these proposed changes and any potential 
effects they may have on the testing process or data integrity.
    NHTSA also seeks comment on the specification in the note to Sec.  
575.104(e)(2)(ix)(C) that the CMT must

[[Page 42768]]

be no more than one year old at the commencement of testing and that it 
must be used within two months after removal from storage. NHTSA lacks 
facilities to store tires in a climate-controlled environment at its 
testing facility in San Angelo, Texas. Therefore, because of the time 
limitations on the use of the CMT in the BCWR testing, NHTSA only 
purchases CMTs on a quarterly basis depending on funding availability 
and conducts BCWR testing as soon as feasible after receiving a 
shipment of CMTs. Lack of funding sometimes requires NHTSA to delay CMT 
purchases, and sometimes when NHTSA purchases CMTs, supplies may be 
limited, meaning that NHTSA is required to wait weeks or months before 
receiving CMTs for testing. To increase NHTSA's flexibility in 
purchasing and testing CMTs, NHTSA is considering lengthening the 
amount of time tires may be removed from storage to four months, so 
that NHTSA can purchase CMTs in advance and store them in its San 
Angelo facility. NHTSA also requests comment on whether the word 
``storage'' is sufficiently well defined and, if not, how NHTSA could 
define ``storage'' more clearly to ensure tires are stored in such a 
way that would minimize testing variability without providing 
inflexible limitations on NHTSA's use of the SRTT. NHTSA requests 
comment on this proposed change.

C. Summary

    Based on the foregoing, NHTSA has tentatively concluded that the 
best course of action in response to Michelin's determination to cease 
production of the 14-inch SRTT is to replace the 14-inch SRTT with the 
16-inch SRTT for all uses in NHTSA's standards and regulations. Because 
the 16-inch SRTT is a different size and made of different materials, 
changes are necessary to the FMVSS and tire regulations to ensure that 
the use of the 16-inch SRTT to evaluate test surface friction does not 
alter the stringency of the standards or the treadwear ratings of tires 
in the UTQGS treadwear testing program. NHTSA tentatively believes that 
this proposal accomplishes those goals. NHTSA requests comment on that 
determination, the merits of these goals, and whether the proposed 
amendments would accomplish those goals. NHTSA also seeks comment on 
the use and storage requirements for the CMT tires used in the BCWR 
calculation.

III. Effective Date

    For the changes to the UTQGS, NHTSA expects to make these changes 
effective at the next BCWR determination at least 30 days after the 
date of publication of a final rule. NHTSA does not believe any further 
lead time is necessary for the following reasons. First, because NHTSA 
is using a conversion factor to keep the rating scale used with the 14-
inch SRTT and 16-inch SRTT identical, ratings of a particular line of 
tires should not be affected by this proposed rule. Second, tire lines 
rated prior to the effective date of the changes proposed in this rule 
would not be required to be rerated. Third, limited availability of the 
14-inch SRTT could make it difficult for NHTSA to continue to obtain 
14-inch SRTTs in its BCWR determinations. NHTSA is currently restricted 
by its regulations to using SRTTs that were manufactured within one 
year prior to the commencement of testing and two months after removal 
from storage in order to prevent variability in results due to tire 
aging. This provision prevents NHTSA from stockpiling 14-inch SRTTs.
    For FMVSS changes, NHTSA is proposing a lead time of six months. 
This will give NHTSA's compliance test facilities sufficient time to 
obtain and validate test surfaces using the 16-inch SRTT. Although 
NHTSA has determined an equivalent level of surface friction when 
evaluating PBC with the 16-inch SRTT in place of the 14-inch SRTT, 
NHTSA anticipates requiring test facilities conducting NHTSA's 
compliance tests to revalidate test surfaces using the 16-inch SRTT, to 
ensure that testing is being done in accordance with the procedures in 
the FMVSS. A six-month lead time is consistent with the requirements of 
49 U.S.C. 30111(d) that standards be effective between 180 days and 1 
year after they are prescribed. However, potential unavailability of 
the 14-inch SRTT may constitute good cause for NHTSA to impose a 
shorter lead time in a final rule resulting from this proposal.
    NHTSA does not believe that manufacturers require more than six 
months of lead time. Because NHTSA intends the proposed peak braking 
coefficient specifications in the FMVSS using the 16-inch SRTT to be an 
equivalent level of friction to existing peak braking coefficients 
using the 14-inch SRTT, NHTSA does not intend to affect the FMVSS 
compliance of any vehicle and does not believe this proposal would do 
so.
    NHTSA requests comments on the proposed lead time for changes to 
the UTQGS and FMVSSs.

IV. Public Participation

How do I prepare and submit comments?

    To ensure that your comments are correctly filed in the Docket, 
please include the docket number of this document in your comments.
    Your comments must not be more than 15 pages long (49 CFR 553.21). 
NHTSA established this limit to encourage you to write your primary 
comments in a concise fashion. However, you may attach necessary 
additional documents to your comments. There is no limit on the length 
of the attachments.
    Please submit your comments electronically to the docket following 
the steps outlined under ADDRESSES. You may also submit two copies of 
your comments, including the attachments, by mail to Docket Management 
at the beginning of this document, under ADDRESSES.

How can I be sure that my comments were received?

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

How do I submit confidential business information?

    If you wish to submit any information under a claim of 
confidentiality, you should submit the following to the NHTSA Office of 
Chief Counsel, 1200 New Jersey Avenue SE, Washington, DC 20590: (1) A 
complete copy of the submission; (2) a redacted copy of the submission 
with the confidential information removed; and (3) either a second 
complete copy or those portions of the submission containing the 
material for which confidential treatment is claimed and any additional 
information that you deem important to the Chief Counsel's 
consideration of your confidentiality claim. A request for confidential 
treatment that complies with 49 CFR part 512 must accompany the 
complete submission provided to the Chief Counsel. For further 
information, submitters who plan to request confidential treatment for 
any portion of their submissions are advised to review 49 CFR part 512, 
particularly those sections relating to document submission 
requirements. Failure to adhere to the requirements of part 512 may 
result in the release of confidential information to the public docket. 
In addition, you should submit two copies from which you have deleted 
the

[[Page 42769]]

claimed confidential business information, to Docket Management at the 
address given at the beginning of this document under ADDRESSES. To 
facilitate social distancing during COVID-19, NHTSA is temporarily 
accepting confidential business information electronically. Please see 
https://www.nhtsa.gov/coronavirus/submission-confidential-business-information for details.

Will the agency consider late comments?

    NHTSA will consider all comments received before the close of 
business on the comment closing date indicated at the beginning of this 
document under DATES. In accordance with DOT policies, to the extent 
possible, NHTSA will also consider comments received after the 
specified comment closing date. If NHTSA receives a comment too late to 
consider in developing the proposed rule, NHTSA will consider that 
comment as an informal suggestion for future rulemaking action.

How can I read the comments submitted by other people?

    You may read the comments received on the internet. To read the 
comments on the internet, go to http://www.regulations.gov and follow 
the on-line instructions provided.
    You may download the comments. The comments are imaged documents, 
in either TIFF or PDF format. Please note that even after the comment 
closing date, NHTSA will continue to file relevant information in the 
Docket as it becomes available. Further, some people may submit late 
comments. Accordingly, NHTSA recommends that you periodically search 
the Docket for new material.
    You may also see the comments at the address and times given near 
the beginning of this document under ADDRESSES.

V. Regulatory Analyses

A. Executive Order 12866, Executive Order 13563, and DOT Rulemaking 
Procedures

    NHTSA has considered the impact of this rulemaking action under 
Executive Order 12866, Executive Order 13563, and the Department of 
Transportation's administrative rulemaking procedures. This rulemaking 
is not considered significant and was not reviewed by the Office of 
Management and Budget under E.O. 12866, ``Regulatory Planning and 
Review.''
    This proposal updates the standard reference test tire used as a 
baseline tire for consumer information testing, in the determination of 
what is a snow tire, and to evaluate testing surface friction for 
evaluating braking and electronic stability control performance. This 
proposal will not have a direct effect on safety because the changes 
proposed in this rule are designed to maintain the present level of 
stringency of NHTSA's braking and electronic stability control FMVSSs. 
However, if the 14-inch SRTT is discontinued without a replacement, 
NHTSA would be unable to verify test surface friction coefficient prior 
to compliance testing for braking and electronic stability control 
system FMVSSs. Thus, this rulemaking indirectly affects safety by 
ensuring that NHTSA would be able to perform compliance tests of those 
FMVSSs. Also, if this proposal were not adopted, it is expected that 
the 14-inch SRTT would soon no longer be available for purchase, 
rendering it impossible for NHTSA to continue maintaining the BCWR for 
treadwear testing. This unavailability of an SRTT would lead to tire 
manufacturers being unable to rate their tires for treadwear under the 
UTQGS and mold those ratings onto the side of the tire as required by 
49 CFR part 575.
    This proposed rule is expected to result in additional costs to 
NHTSA because the 16-inch SRTT has a retail price that is $35 per tire 
more than the 14-inch SRTT ($335 vs. $300).\19\ NHTSA purchases 64 
SRTTs for its own use annually in determining BCWR. Therefore, based on 
the cost difference of $35 per tire, NHTSA expects that, if adopted, 
this proposal would result in $2,240 additional annual costs to the 
government. However, NHTSA has been using the 14-inch SRTT and 16-inch 
SRTT side-by-side since 2016 for its quarterly BCWR determination in 
anticipation of this rulemaking and NHTSA plans to continue to do so 
until this proposal is finalized. After this proposal is finalized, 
NHTSA does not expect to continue purchasing 14-inch SRTTs. Therefore, 
when compared to years since 2016, NHTSA would likely purchase fewer 
SRTTs in subsequent years after this proposal is finalized.
---------------------------------------------------------------------------

    \19\ Data on the price of the SRTT was obtained from 
instructions on how to purchase SRTTs from Michelin. See https://www.astm.org/COMMIT/2011%2011%2008%20E1136%20F2493%20SRTT%20Purchase%20Procedure.pdf. 
(last accessed April 13, 2021).
---------------------------------------------------------------------------

    As to potential costs to the public, based upon information 
provided to NHTSA by Michelin from 2017 and 2018, annual U.S. sales of 
14-inch SRTTs is fewer than 2,000 units. Assuming that U.S. sales of 
16-inch SRTTs is comparable to sales of 14-inch SRTTs, the annual cost 
of this proposal would be less than $70,000. However, NHTSA does not 
know how many sales are a consequence of the SRTT being used as part of 
NHTSA's compliance test procedures, versus those sold for other 
purposes (e.g., SRTTs sold to assess the performance of tires to some 
other country's regulations or to voluntary industry standards). Any 
SRTT sales that are not related to compliance with NHTSA's regulations 
would not be affected by this proposal and the existence of such sales 
would mean this rule would be less costly than the maximum estimate of 
$70,000 per year. Moreover, NHTSA does not have any direct knowledge of 
whether regulated entities have been conducting side-by-side testing 
using both the 14-inch SRTT and 16-inch SRTTs like NHTSA has and 
whether side-by-side testing has artificially increased sales in 2017 
and 2018.
    NHTSA requests comments on the benefits and costs of this NPRM.

B. Regulatory Flexibility Act

    Pursuant to the Regulatory Flexibility Act (5 U.S.C. 601 et seq., 
as amended by the Small Business Regulatory Enforcement Fairness Act 
(SBREFA) of 1996), whenever an agency is required to publish a notice 
of rulemaking for any proposed or final rule, it must prepare and make 
available for public comment a regulatory flexibility analysis that 
describes the effect of the rule on small entities (i.e., small 
businesses, small organizations, and small governmental jurisdictions). 
The Small Business Administration's regulations at 13 CFR part 121 
define a small business, in part, as a business entity ``which operates 
primarily within the United States.'' (13 CFR 121.105(a)). However, no 
regulatory flexibility analysis is required if the head of an agency 
certifies the rule would not have a significant economic impact on a 
substantial number of small entities. SBREFA amended the Regulatory 
Flexibility Act to require Federal agencies to provide a statement of 
the factual basis for certifying that a rule would not have a 
significant economic impact on a substantial number of small entities.
    NHTSA has considered the effects of this proposal under the 
Regulatory Flexibility Act. I certify that this proposal will not have 
a significant economic impact on a substantial number of small 
entities. This proposal would directly impact the government, as it 
affects only the test procedures NHTSA uses in its FMVSSs and 
regulations that reference tire performance. It affects manufacturers 
of tires and of motor vehicles only to the

[[Page 42770]]

extent those manufacturers choose to test their products in the manner 
NHTSA would test them. They are not required to use the test procedures 
NHTSA uses.
    Although we believe some entities producing tires or vehicles that 
would be tested by NHTSA using procedures that use the 16-inch SRTT are 
considered small businesses, we do not believe this proposal will have 
a significant economic impact on those manufacturers. First, the small 
manufacturers are not required to use the SRTT in certifying their 
products. Second, for manufacturers choosing to use the 16-inch SRTT to 
test their products, this proposal would result in a cost increase of 
only $35 per tire to entities currently purchasing the 14-inch SRTT to 
assess their products. We do not believe this cost increase is 
significant. Finally, for the changes to the UTQGS, because NHTSA is 
using a conversion factor to keep the rating scale used with the 14-
inch SRTT and 16-inch SRTT identical, ratings of a particular line of 
tires should not be affected by this proposed rule. For FMVSS changes, 
NHTSA has determined an equivalent level of surface friction when 
evaluating PBC with the 16-inch SRTT in place of the 14-inch SRTT, so 
the change to the standard reference test tire should not change the 
performance of current tires or vehicles.

C. Executive Order 13132 (Federalism)

    NHTSA has examined this proposal pursuant to Executive Order 13132 
(64 FR 43255, August 10, 1999) and concluded that no additional 
consultation with States, local governments or their representatives is 
mandated beyond the rulemaking process. The agency has concluded that 
the rulemaking would not have sufficient federalism implications to 
warrant consultation with State and local officials or the preparation 
of a federalism summary impact statement. The proposal would not have 
``substantial direct effects on the States, on the relationship between 
the national government and the States, or on the distribution of power 
and responsibilities among the various levels of government.''
    NHTSA rules can preempt in two ways. First, the National Traffic 
and Motor Vehicle Safety Act contains an express preemption provision: 
When a motor vehicle safety standard is in effect under this chapter, a 
State or a political subdivision of a State may prescribe or continue 
in effect a standard applicable to the same aspect of performance of a 
motor vehicle or motor vehicle equipment only if the standard is 
identical to the standard prescribed under this chapter. 49 U.S.C. 
30103(b)(1). It is this statutory command by Congress that preempts any 
non-identical State legislative and administrative law addressing the 
same aspect of performance.
    The express preemption provision described above is subject to a 
savings clause under which ``[c]ompliance with a motor vehicle safety 
standard prescribed under this chapter does not exempt a person from 
liability at common law.'' 49 U.S.C. 30103(e). Pursuant to this 
provision, State common law tort causes of action against motor vehicle 
manufacturers that might otherwise be preempted by the express 
preemption provision are generally preserved. However, the Supreme 
Court has recognized the possibility, in some instances, of implied 
preemption of such State common law tort causes of action by virtue of 
NHTSA's rules, even if not expressly preempted. This second way that 
NHTSA rules can preempt is dependent upon there being an actual 
conflict between an FMVSS and the higher standard that would 
effectively be imposed on motor vehicle manufacturers if someone 
obtained a State common law tort judgment against the manufacturer, 
notwithstanding the manufacturer's compliance with the NHTSA standard. 
Because most NHTSA standards established by an FMVSS are minimum 
standards, a State common law tort cause of action that seeks to impose 
a higher standard on motor vehicle manufacturers will generally not be 
preempted. However, if and when such a conflict does exist--for 
example, when the standard at issue is both a minimum and a maximum 
standard--the State common law tort cause of action is impliedly 
preempted. See Geier v. American Honda Motor Co., 529 U.S. 861 (2000).
    Pursuant to Executive Orders 13132 and 12988, NHTSA has considered 
whether this proposed rule could or should preempt State common law 
causes of action. The agency's ability to announce its conclusion 
regarding the preemptive effect of one of its rules reduces the 
likelihood that preemption will be an issue in any subsequent tort 
litigation.
    To this end, the agency has examined the nature (e.g., the language 
and structure of the regulatory text) and objectives of this proposed 
rule and finds that this proposal would affect only minimum safety 
standards (and only insofar as how NHTSA would conduct compliance 
testing under those standards). As such, NHTSA does not intend that 
this proposed rule preempt State tort law that would effectively impose 
a higher standard on motor vehicle manufacturers than that established 
by the affected FMVSSs. Establishment of a higher standard by means of 
State tort law would not conflict with the minimum standards affected 
by this proposal. Without any conflict, there could not be any implied 
preemption of a State common law tort cause of action. Aspects of this 
proposed rule would amend 49 CFR part 575, which is not a safety 
standard but an information program to assist consumers in making 
informed decisions when purchasing tires. The 14-inch SRTT is used as 
part of the determination of a tire's treadwear rating. This proposed 
change would not impose any requirements on anyone.

D. Executive Order 12988 (Civil Justice Reform)

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

E. Protection of Children From Environmental Health and Safety Risks

    Executive Order 13045, ``Protection of Children from Environmental 
Health and Safety Risks'' (62 FR 19855, April 23, 1997), applies to any 
rule that: (1) Is determined to be ``economically significant'' as 
defined under Executive Order 12866, and (2) concerns an environmental, 
health, or safety risk that the agency has reason to believe may have a 
disproportionate effect on children. If the regulatory action meets

[[Page 42771]]

both criteria, the agency must evaluate the environmental health or 
safety effects of the planned rule on children, and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the agency.
    This proposal is not economically significant under E.O. 12866. 
Further, it is part of a rulemaking that is not expected to have a 
disproportionate health or safety impact on children. Consequently, no 
further analysis is required under Executive Order 13045.

F. Paperwork Reduction Act

    Under the Paperwork Reduction Act of 1995 (PRA), a person is not 
required to respond to a collection of information by a Federal agency 
unless the collection displays a valid Office of Management and Budget 
(OMB) control number. There is not any information collection 
requirement associated with this proposal.

G. Incorporation by Reference

    Under regulations issued by the Office of the Federal Register (1 
CFR 51.5(a)), an agency, as part of a proposed rule that includes 
material incorporated by reference, must summarize material that is 
proposed to be incorporated by reference and must discuss the ways the 
material proposed to be incorporated by reference is reasonably 
available to interested parties or how the agency worked to make 
materials available to interested parties.
    This proposed rule would incorporate by reference ASTM F2493, 
``Standard Specification for P225/60R16 97S Radial Standard Reference 
Test Tire,'' to replace the existing incorporation by reference of ASTM 
E1136, which is a 14-inch standard reference test tire. As discussed 
earlier in this document, the ASTM F2493 is a standard reference test 
tire that is not used for general use, but, as its name suggests, is 
used for testing. The ASTM F2493 standard reference test tire is 
primarily used for evaluating surface friction (traction). The standard 
reference test tire specifications include, among other things, size, 
design, construction, and materials requirements.
    This proposed rule would also update an existing incorporation by 
reference of ASTM E1337, ``Standard Test Method for Determining 
Longitudinal Peak Braking Coefficient (PBC) of Paved Surfaces Using 
Standard Reference Test Tire.'' ASTM E1337 is a standard test method 
for evaluating peak braking coefficient of a test surface using a 
standard reference test tire using a trailer towed by a vehicle. NHTSA 
uses this method to evaluate test surfaces for conducting compliance 
test procedures for its braking and electronic stability control 
standards. The 2019 version of ASTM E1337 specifies that the test may 
be conducted using the 16-inch SRTT and includes correlation data for 
converting testing using the 14-inch SRTT to the 16-inch SRTT and vice 
versa.
    Finally, this proposed rule would update an existing incorporation 
by reference of ASTM F1805, ``Standard Test Method for Single Wheel 
Driving Traction in a Straight Line on Snow- and Ice-Covered 
Surfaces.'' ASTM F1805 is a test method for measuring the traction of 
tires on snow- or ice-covered surfaces using an instrumented four-wheel 
drive vehicle with a single test wheel capable of measure tire 
performance. NHTSA uses ASTM F1805 as part of its criteria for 
determining whether a tire may be considered a ``snow tire'' under its 
light vehicle tire standards. The 2020 version of F1805 specifies that 
the test may be conducted using the 16-inch SRTT and includes 
correlation data for converting testing using the 14-inch SRTT to the 
16-inch SRTT and vice versa.
    The ASTM standards proposed for incorporation by reference in this 
NPRM are available for review at NHTSA's headquarters in Washington, 
DC, and for purchase from ASTM International. The ASTM standards that 
are currently incorporated by reference (and which would be replaced 
under this proposal) are available for review at NHTSA or at ASTM 
International's online reading room.\20\ If this proposal is adopted as 
a final rule, NHTSA anticipates that ASTM International would update 
its reading room to include these standards.
---------------------------------------------------------------------------

    \20\ https://www.astm.org/READINGLIBRARY/.
---------------------------------------------------------------------------

H. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act (NTTAA) requires NHTSA to evaluate and use existing voluntary 
consensus standards in its regulatory activities unless doing so would 
be inconsistent with applicable law (e.g., the statutory provisions 
regarding NHTSA's vehicle safety authority) or otherwise impractical. 
Voluntary consensus standards are technical standards developed or 
adopted by voluntary consensus standards bodies. Technical standards 
are defined by the NTTAA as ``performance-based or design-specific 
technical specification and related management systems practices.'' 
They pertain to ``products and processes, such as size, strength, or 
technical performance of a product, process or material.''
    Examples of organizations generally regarded as voluntary consensus 
standards bodies include ASTM International, the Society of Automotive 
Engineers (SAE), and the American National Standards Institute (ANSI). 
If NHTSA does not use available and potentially applicable voluntary 
consensus standards, we are required by the Act to provide Congress, 
through OMB, an explanation of the reasons for not using such 
standards.
    As discussed above, both standard reference test tires are based on 
specifications published by ASTM International. Thus, this rulemaking 
accords with the requirements of the NTTAA.

I. Unfunded Mandates Reform Act

    Section 202 of the Unfunded Mandates Reform Act of 1995 (UMRA) 
requires Federal agencies to prepare a written assessment of the costs, 
benefits, and other effects of proposed or final rules that include a 
Federal mandate likely to result in the expenditure by State, local, or 
tribal governments, in the aggregate, or by the private sector, of more 
than $100 million annually (adjusted for inflation with base year of 
1995). Before promulgating a NHTSA rule for which a written statement 
is needed, section 205 of the UMRA generally requires the agency to 
identify and consider a reasonable number of regulatory alternatives 
and adopt the least costly, most cost-effective, or least burdensome 
alternative that achieves the objectives of the rule. The provisions of 
section 205 do not apply when they are inconsistent with applicable 
law. Moreover, section 205 allows the agency to adopt an alternative 
other than the least costly, most cost-effective, or least burdensome 
alternative if the agency publishes with the final rule an explanation 
of why that alternative was not adopted.
    This proposal would not result in any expenditure by State, local, 
or tribal governments or the private sector of more than $100 million, 
adjusted for inflation.

J. National Environmental Policy Act

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

K. Regulation Identifier Number (RIN)

    The Department of Transportation assigns a regulation identifier 
number

[[Page 42772]]

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

List of Subjects

49 CFR Part 571

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

49 CFR Part 575

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

    In consideration of the foregoing, NHTSA proposes to amend 49 CFR 
parts 571 and 575 as follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

0
1. The authority citation for part 571 of title 49 continues to read as 
follows:

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

0
2. Amend Sec.  571.5 by revising paragraphs (d)(33) through (35) to 
read as follows:

Sec.  571.5  Matter incorporated by reference.

* * * * *
    (d) * * *
    (33) ASTM E1337-19, ``Standard Test Method for Determining 
Longitudinal Peak Braking Coefficient (PBC) of Paved Surfaces Using 
Standard Reference Test Tire,'' approved December 1, 2019, into 
Sec. Sec.  571.105; 571.121; 571.122; 571.126; 571.135; 571.136; 
571.500.
    (34) ASTM F1805-20, ``Standard Test Method for Single Wheel Driving 
Traction in a Straight Line on Snow- and Ice-Covered Surfaces,'' 
approved May 1, 2020, into Sec.  571.139.
    (35) ASTM F2493-19, ``Standard Specification for P225/60R16 97S 
Radial Standard Reference Test Tire,'' approved Oct. 1, 2019, into 
Sec. Sec.  571.105; 571.121; 571.122; 571.126; 571.135; 571.136; 
571.139; 571.500.
* * * * *
0
3. Amend Sec.  571.105 by removing paragraphs S6.9.2(a) and S6.9.2(b) 
and adding paragraph S6.9.2 to read as follows:

Sec.  571.105  Standard No. 105; Hydraulic and electric brake systems.

* * * * *
    S6.9.2 (a) For vehicles with a GVWR greater than 10,000 pounds, 
road tests (excluding stability and control during braking tests) are 
conducted on a 12-foot-wide, level roadway, having a peak friction 
coefficient of 1.02 when measured using an ASTM F2493-19 (incorporated 
by reference, see Sec.  571.5), standard reference test tire, in 
accordance with ASTM E1337-19 (incorporated by reference, see Sec.  
571.5), at a speed of 40 mph, without water delivery. Burnish stops are 
conducted on any surface. The parking brake test surface is clean, dry, 
smooth, Portland cement concrete.
    (b) For vehicles with a GVWR greater than 10,000 pounds, stability 
and control during braking tests are conducted on a 500-foot-radius 
curved roadway with a wet level surface having a peak friction 
coefficient of 0.55 when measured on a straight or curved section of 
the curved roadway using an ASTM F2493-19 standard reference tire, in 
accordance with ASTM E1337-19 at a speed of 40 mph, with water 
delivery.
* * * * *
0
4. Amend Sec.  571.121 by revising paragraphs S5.3.1.1 introductory 
text, S5.3.6.1, S5.7.1, S6.1.7, Table I, Table II, and Table IIa to 
read as follows:

Sec.  571.121  Standard No. 121; Air brake systems.

* * * * *
    S5.3.1.1 Stop the vehicle from 60 mph on a surface with a peak 
friction coefficient of 1.02 with the vehicle loaded as follows:
* * * * *
    S5.3.6.1 Using a full-treadle brake application for the duration of 
the stop, stop the vehicle from 30 mph or 75 percent of the maximum 
drive-through speed, whichever is less, on a 500-foot radius curved 
roadway with a wet level surface having a peak friction coefficient of 
0.55 when measured on a straight or curved section of the curved 
roadway using an ASTM F2493-19 (incorporated by reference, see Sec.  
571.5) standard reference tire, in accordance with ASTM E1337-19 
(incorporated by reference, see Sec.  571.5), at a speed of 40 mph, 
with water delivery.
* * * * *
    S5.7.1 Emergency brake system performance. When stopped six times 
for each combination of weight and speed specified in S5.3.1.1, except 
for a loaded truck tractor with an unbraked control trailer, on a road 
surface having a PFC of 1.02, with a single failure in the service 
brake system of a part designed to contain compressed air or brake 
fluid (except failure of a common valve, manifold, brake fluid housing, 
or brake chamber housing), the vehicle shall stop at least once in not 
more than the distance specified in Column 5 of Table II, measured from 
the point at which movement of the service brake control begins, except 
that a truck-tractor tested at its unloaded vehicle weight plus up to 
1,500 pounds shall stop at least once in not more than the distance 
specified in Column 6 of Table II. The stop shall be made without any 
part of the vehicle leaving the roadway, and with unlimited wheel 
lockup permitted at any speed.
* * * * *
    S6.1.7 Unless otherwise specified, stopping tests are conducted on 
a 12-foot wide level, straight roadway having a peak friction 
coefficient of 1.02. For road tests in S5.3, the vehicle is aligned in 
the center of the roadway at the beginning of a stop. Peak friction 
coefficient is measured using an ASTM F2493-19 standard reference test 
tire (see ASTM F2493-19 (incorporated by reference, see Sec.  571.5)) 
in accordance with ASTM E1337-19 (incorporated by reference, see Sec.  
571.5), at a speed of 40 mph, without water delivery for the surface 
with PFC of 1.02, and with water delivery for the surface with PFC of 
0.55.
* * * * *

                       Table I--Stopping Sequence
------------------------------------------------------------------------
                                                            Single unit
                                          Truck tractors    trucks and
                                                               buses
------------------------------------------------------------------------
Burnish (S6.1.8)........................               1               1
Stability and Control at GVWR (S5.3.6)..               2             N/A
Stability and Control at LLVW (S5.3.6)..               3               5
Manual Adjustment of Brakes.............               4             N/A
60 mph Service Brake Stops at GVWR                     5               2
 (S5.3.1)...............................
60 mph Emergency Service Brake Stops at              N/A               3
 GVWR (S5.7.1)..........................

[[Page 42773]]

 
Parking Brake Test at GVWR (S5.6).......               6               4
Manual Adjustment of Brakes.............               7               6
60 mph Service Brake Stops at LLVW                     8               7
 (S5.3.1)...............................
60 mph Emergency Service Brake Stops at                9               8
 LLVW (S5.7.1)..........................
Parking Brake Test at LLVW (S5.6).......              10               9
Final Inspection........................              11              10
------------------------------------------------------------------------

                                                           Table II--Stopping Distance in Feet
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                  Service brake                                      Emergency brake
         Vehicle speed in miles per hour         -------------------------------------------------------------------------------------------------------
                                                      (1)          (2)          (3)          (4)          (5)          (6)          (7)          (8)
--------------------------------------------------------------------------------------------------------------------------------------------------------
30..............................................           70           78           65           78           84           61          170          186
35..............................................           96          106           89          106          114           84          225          250
40..............................................          125          138          114          138          149          108          288          325
45..............................................          158          175          144          175          189          136          358          409
50..............................................          195          216          176          216          233          166          435          504
55..............................................          236          261          212          261          281          199          520          608
60..............................................          280          310          250          310          335          235          613          720
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note:
(1) Loaded and Unloaded Buses.
(2) Loaded Single-Unit Trucks.
(3) Loaded Tractors with Two Axles; or with Three Axles and a GVWR of 70,000 lbs. or less; or with Four or More Axles and a GVWR of 85,000 lbs. or less.
  Tested with an Unbraked Control Trailer.
(4) Loaded Tractors with Three Axles and a GVWR greater than 70,000 lbs.; or with Four or More Axles and a GVWR greater than 85,000 lbs. Tested with an
  Unbraked Control Trailer.
(5) Unloaded Single-Unit Trucks.
(6) Unloaded Tractors (Bobtail).
(7) All Vehicles except Tractors, Loaded and Unloaded.
(8) Unloaded Tractors (Bobtail).

 Table IIa--Stopping Distance in Feet: Optional Requirements for: (1) Three-Axle Tractors With a Front Axle That
Has a GAWR of 14,600 Pounds or Less, and With Two Rear Drive Axles That Have a Combined GAWR of 45,000 Pounds or
     Less, Manufactured Before August 1, 2011; and (2) All Other Tractors Manufactured Before August 1, 2013
----------------------------------------------------------------------------------------------------------------
                                                       Service Brake                         Emergency Brake
  Vehicle speed in miles per hour  -----------------------------------------------------------------------------
                                        (1)          (2)          (3)          (4)          (5)          (6)
----------------------------------------------------------------------------------------------------------------
30................................           70           78           84           89          170          186
35................................           96          106          114          121          225          250
40................................          125          138          149          158          288          325
45................................          158          175          189          200          358          409
50................................          195          216          233          247          435          504
55................................          236          261          281          299          520          608
60................................          280          310          335          355          613          720
----------------------------------------------------------------------------------------------------------------
Note: (1) Loaded and unloaded buses; (2) Loaded single unit trucks; (3) Unloaded truck tractors and single unit
  trucks; (4) Loaded truck tractors tested with an unbraked control trailer; (5) All vehicles except truck
  tractors; (6) Unloaded truck tractors.

* * * * *
0
5. Amend Sec.  571.122 by revising paragraphs S6.1.1.1, S6.1.1.2, 
S6.1.1.3, and S6.9.7.1(a) to read as follows:

Sec.  571.122  Standard No. 122; Motorcycle brake systems.

* * * * *
    S6.1.1.1 High friction surface. A high friction surface is used for 
all dynamic brake tests excluding the ABS tests where a low-friction 
surface is specified. The high-friction surface test area is a clean, 
dry and level surface, with a gradient of <=1 percent. The high-
friction surface has a peak braking coefficient (PBC) of 1.02.
    S6.1.1.2 Low-friction surface. A low-friction surface is used for 
ABS tests where a low-friction surface is specified. The low-friction 
surface test area is a clean and level surface, which may be wet or 
dry, with a gradient of <=1 percent. The low-friction surface has a PBC 
of <=0.50.
    S6.1.1.3 Measurement of PBC. The PBC is measured using the ASTM 
F2493-19 standard reference test tire, in accordance with ASTM E1337-
19, at a speed of 64 km/h (both publications incorporated by reference; 
see Sec.  571.5).
* * * * *
    S6.9.7.1 * * *
    (a) Test surfaces. A low friction surface immediately followed by a 
high friction surface with a PBC >=0.90.
* * * * *
0
6. Amend Sec.  571.126 by revising paragraph S6.2.2 to read as follows:

Sec.  571.126  Standard No. 126; Electronic stability control systems 
for light vehicles.

* * * * *

[[Page 42774]]

    S6.2.2 The road test surface must produce a peak friction 
coefficient (PFC) of 1.02 when measured using an ASTM F2493-19 
(incorporated by reference, see Sec.  571.5) standard reference test 
tire, in accordance with ASTM E1337-19 (incorporated by reference, see 
Sec.  571.5) at a speed of 64.4 km/h (40 mph), without water delivery.
* * * * *
0
7. Amend Sec.  571.135 by revising paragraphs S6.2.1, S7.4.3(f), 
S7.5.2(f), S7.6.2(f), S7.7.3(f), S7.8.2(f), S7.9.2(f), S7.10.3(e), and 
S7.11.3(f) to read as follows:

Sec.  571.135  Standard No. 135; Light vehicle brake systems.

* * * * *
    S6.2.1 Unless otherwise specified, the road test surface produces a 
peak friction coefficient (PFC) of 1.02 when measured using an ASTM 
F2493-19 (incorporated by reference, see Sec.  571.5) standard 
reference test tire, in accordance with ASTM E1337-19 (incorporated by 
reference, see Sec.  571.5), at a speed of 64.4 km/h (40 mph), without 
water delivery.
* * * * *
    S7.4.3 * * *
    (f) Test surface: PFC of at least 1.02.
* * * * *
    S7.5.2 * * *
    (f) Test surface: PFC of 1.02.
* * * * *
    S7.6.2 * * *
    (f) Test surface: PFC of 1.02.
* * * * *
    S7.7.3 * * *
    (f) Test surface: PFC of 1.02.
* * * * *
    S7.8.2 * * *
    (f) Test surface: PFC of 1.02.
* * * * *
    S7.9.2 * * *
    (f) Test surface: PFC of 1.02.
* * * * *
    S7.10.3 * * *
    (e) Test surface: PFC of 1.02.
* * * * *
    S7.11.3 * * *
    (f) Test surface: PFC of 1.02.
* * * * *
0
8. Amend Sec.  571.136 by revising paragraph S6.2.2 to read as follows:

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

* * * * *
    S6.2.2 The road test surface produces a peak friction coefficient 
(PFC) of 1.02 when measured using an ASTM F2493-19 standard reference 
test tire, in accordance with ASTM E1337-19, at a speed of 64.4 km/h 
(40 mph), without water delivery (both documents incorporated by 
reference, see Sec.  571.5).
* * * * *
0
9. Amend Sec.  571.139 by revising the definition of ``Snow tire'' in 
S3 to read as follows:

Sec.  571.139  Standard No. 139; New pneumatic radial tires for light 
vehicles.

* * * * *
    S3 * * *
    Snow tire means a tire that attains a traction index equal to or 
greater than 112, compared to the ASTM F2493-19 (incorporated by 
reference, see Sec.  571.5) Standard Reference Test Tire when using the 
snow traction test on the medium pack snow surface as described in ASTM 
F1805-20 (incorporated by reference, see Sec.  571.5), and that is 
marked with an Alpine Symbol specified in S5.5(i) on at least one 
sidewall.
* * * * *
0
10. Amend Sec.  571.500 by revising paragraph S6.2.1 to read as 
follows:

Sec.  571.500  Standard No. 500; Low-speed vehicles.

* * * * *
    S6.2.1 Pavement friction. Unless otherwise specified, the road test 
surface produces a peak friction coefficient (PFC) of 1.02 when 
measured using a standard reference test tire that meets the 
specifications of ASTM F2493-19, in accordance with ASTM E1337-19, at a 
speed of 64.4 km/h (40.0 mph), without water delivery (both 
incorporated by reference; see Sec.  571.5).
* * * * *

PART 575--CONSUMER INFORMATION

0
11. The authority citation for part 575 of title 49 continues to read 
as follows:

    Authority: 49 U.S.C. 32302, 32304A, 30111, 30115, 30117, 30123, 
30166, 30181, 30182, 30183, and 32908, Pub. L. 104-414, 114 Stat. 
1800, Pub. L. 109-59, 119 Stat. 1144, Pub. L. 110-140, 121 Stat. 
1492, 15 U.S.C. 1232(g); delegation of authority at 49 CFR 1.95.

0
12. Amend Sec.  575.3 by revising paragraph (c) to read as follows:

Sec.  575.3  Matter incorporated by reference.

* * * * *
    (c) ASTM International (ASTM), 100 Barr Harbor Drive, P.O. Box 
C700, West Conshohocken, PA 19428-2959, 610-832-9500, https://www.astm.org/.
    (1) ASTM E 501-08 (``ASTM E 501''), ``Standard Specification for 
Standard Rib Tire for Pavement Skid-Resistance Tests'' (June 2008), IBR 
approved for Sec. Sec.  575.104 and 575.106.
    (2) ASTM F2493-19 (``ASTM F2493''), ``Standard Specification for 
P225/60R16 97S Radial Standard Reference Test Tire,'' (approved Oct. 1, 
2019), IBR approved for Sec.  575.104.
* * * * *
0
13. Amend Sec.  575.104 by revising paragraphs (e)(2)(viii) 
introductory text, (e)(2)(viii)(A) through (E), and (e)(2)(ix)(A)(2), 
the note to paragraph (e)(2)(ix)(C), and paragraph (e)(2)(ix)(F) to 
read as follows:

Sec.  575.104   Uniform tire quality grading standards.

* * * * *
    (e) * * *
    (2) * * *
    (viii) Drive the convoy on the test roadway for 16 circuits 
(approximately 6,400 miles).
    (A) After every circuit (approximately 400 miles), rotate each 
vehicle's tires by moving each front tire to the same side of the rear 
axle and each rear tire to the opposite side of the front axle. 
Visually inspect each tire for treadwear anomalies.
    (B) After every second circuit (approximately 800 miles), rotate 
the vehicles in the convoy by moving the last vehicle to the lead 
position. Do not rotate driver positions within the convoy. In four-car 
convoys, vehicle one shall become vehicle two, vehicle two shall become 
vehicle three, vehicle three shall become vehicle four, and vehicle 
four shall become vehicle one.
    (C) After every second circuit (approximately 800 miles), if 
necessary, adjust wheel alignment to the midpoint of the vehicle 
manufacturer's specification, unless adjustment to the midpoint is not 
recommended by the manufacturer; in that case, adjust the alignment to 
the manufacturer's recommended setting. In all cases, the setting is 
within the tolerance specified by the manufacturer of the alignment 
machine.
    (D) After every second circuit (approximately 800 miles), if 
determining the projected mileage by the 9-point method set forth in 
paragraph (e)(2)(ix)(A)(1) of this section, measure the average tread 
depth of each tire following the procedure set forth in paragraph 
(e)(2)(vi) of this section.
    (E) After every fourth circuit (approximately 1,600 miles), move 
the complete set of four tires to the following vehicle. Move the tires 
on the last vehicle to the lead vehicle. In moving the tires, rotate 
them as set forth in paragraph (e)(2)(viii)(A) of this section.
* * * * *
    (ix) * * *
    (A) * * *
    (2) Two-point arithmetical method. (i) For each course monitoring 
and

[[Page 42775]]

candidate tire in the convoy, using the average tread depth 
measurements obtained in accordance with paragraphs (e)(2)(vi) and 
(e)(2)(viii)(F) of this section and the corresponding mileages as data 
points, determine the slope (m) of the tire's wear in mils of tread 
depth per 1,000 miles by the following formula:
[GRAPHIC] [TIFF OMITTED] TP05AU21.039

Where:

Yo = average tread depth after break-in, mils.
Y1 = average tread depth after 16 circuits (approximately 6,400 
miles), mils.
Xo = 0 miles (after break-in).
X1 = Total mileage of travel after 16 circuits (approximately 6,400 
miles).

    (ii) This slope (m) will be negative in value. The tire's wear rate 
is defined as the slope (m) expressed in mils per 1,000 miles.
* * * * *
    (C) * * *

    Note to paragraph (e)(2)(ix)(C):  The base wear rate for the 
course monitoring tires (CMTs) will be obtained by the Government by 
running the tire specified in ASTM F2493 (incorporated by reference, 
see Sec.  575.3) course monitoring tires for 16 circuits over the 
San Angelo, Texas, UTQGS test route 4 times per year, then using the 
average wear rate from the last 4 quarterly CMT tests for the base 
course wear rate calculation. Each new base course wear rate will be 
published in Docket No. NHTSA-2001-9395. The course monitoring tires 
used in a test convoy must be no more than one-year-old at the 
commencement of the test and must be used within four months after 
removal from storage.

* * * * *
    (F) Compute the grade (P) of the of the NHTSA nominal treadwear 
value for each candidate tire by using the following formula:
[GRAPHIC] [TIFF OMITTED] TP05AU21.040

Where base course wear raten = new base course wear rate, 
i.e., average treadwear of the last 4 quarterly course monitoring tire 
tests conducted by NHTSA.

    Round off the percentage to the nearest lower 20-point increment.
* * * * *

    Issued in Washington, DC, under authority delegated in 49 CFR 
1.95 and 501.8.
Steven S. Cliff,
Acting Administrator.
[FR Doc. 2021-15361 Filed 8-4-21; 8:45 am]
BILLING CODE 4910-59-P