42762 Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Proposed Rules 

§ 165.519 Safety Zones; Hampton Roads 

Bridge-Tunnel Expansion Project, Hampton/ 

Norfolk, VA. 

(a) Definitions. As used in this 

section, designated representative 

means a Coast Guard Patrol 

Commander, including a Coast Guard 

coxswain, petty officer, or other officer 

operating a Coast Guard vessel and a 

Federal, State, and local officer 

designated by or assisting the Captain of 

the Port Virginia in the enforcement of 

the safety zone. The term also includes 

an employee or contractor of Hampton 

Roads Connector Partners (HRCP) for 

the sole purposes of designating and 

establishing safe transit corridors, to 

permit passage into or through these 

safety zones, or to notify vessels and 

individuals that they have entered a 

safety zone and are required to leave. 

(b) Locations and zone-specific 

requirements. 

(1) Zone 1, Hampton Flats Mooring 

Area. 

(i) Location: All waters of the 

Hampton Flats, from surface to bottom, 

encompassed by a line connecting the 

following points beginning at 

36°59′40.41′′ N, 76°22′10.66′′ W, thence 

to 37°00′01.84′′ N, 76°21′01.69′′ W, 

thence to 36°59′52.62′′ N, 76°20′57.23′′ 

W, thence to 36°59′31.19′′ N, 

76°22′06.20′′ W, and back to the 

beginning point. 

(ii) Requirements: No vessel or person 

may enter or remain in the safety zone 

without permission of the COTP, HRCP, 

or designated representative. Mariners 

must observe lighted marker buoys 

along the perimeter and at each of the 

corners marking the safety zone. 

(2) Zone 2, Phoebus Safe Harbor Area. 

(i) Location: All waters west of the 

Phoebus Channel, from surface to 

bottom, encompassed by a line 

connecting the following points 

beginning at 37°00′34.26′′ N, 

76°19′10.58′′ W, thence to 37°00′23.97′′ 

N, 76°19′06.16′′ W, thence to 

37°00′22.52′′ N, 76°19′11.41′′ W, thence 

to 37°00′32.81′′ N, 76°19′15.81′′ W, and 

back to the beginning point. 

(ii) Requirements: No vessel or person 

may enter or remain in the safety zone 

during announced enforcement periods 

without permission of the COTP, HRCP, 

or designated representative. Such 

enforcement periods will be announced 

by Sector Virginia Broadcast Notice to 

Mariners and broadcasts on VHF–FM 

radio. During enforcement periods, 

mariners shall observe lighted marker 

buoys along the perimeter and at each 

of the corners marking the safety zone. 

(3) Zone 3, Willoughby Bay Mooring 

Area. 

(i) Location: All waters of Willoughby 

Bay, from surface to bottom, in the area 

encompassed by a line connecting the 

following points beginning at 

36°57′48.68′′ N, 76°17′08.20′′ W, thence 

to 36°57′44.84′′ N, 76°16′44.48′′ W, 

thence to 36°57′35.31′′ N, 76°16′42.80′′ 

W, thence to 36°57′28.78′′ N, 

76°16′51.75′′ W, thence to 36°57′33.17′′ 

N, 76°17′19.43′′ W, and back to the 

beginning point. 

(ii) Requirements: No vessel or person 

may enter or remain in the safety zone 

without permission of the COTP, HRCP, 

or designated representative. Mariners 

must observe lighted marker buoys 

along the perimeter and at each of the 

corners marking the safety zone. 

(4) Zone 4, North Highway Bridge 

Trestle and North Island. 

(i) Location: All waters, from surface 

to bottom, located within 300 feet of the 

east or west side of the Hampton Roads 

Bridge-Tunnel’s north highway bridge 

trestle, including North Island, to the 

shore of the City of Hampton. No vessel 

or person may enter or remain in the 

safety zone without permission of the 

COTP, HRCP, or designated 

representative. 

(ii) Requirements: All mariners 

attempting to enter or depart the 

Hampton Creek Approach Channel or 

the Phoebus Channel in the vicinity of 

the North Island must proceed with 

extreme caution and maintain a safe 

distance from construction equipment. 

(5) Zone 5, South Highway Bridge 

Trestle and South Island. 

(i) Location: All waters, from surface 

to bottom, located within 300 feet from 

the east or west side of the Hampton 

Roads Bridge-Tunnel’s south highway 

bridge trestle, including South Island, to 

the shore of the City of Norfolk. 

(ii) Requirements: No vessel or person 

may enter or remain in the safety zone 

without permission of the COTP, HRCP, 

or designated representative. HRCP may 

establish and post visual identification 

of safe transit corridors that vessels may 

use to freely proceed through the safety 

zone. All mariners attempting to enter 

or depart the Willoughby Bay Approach 

Channel in the vicinity of the South 

Island shall proceed with extreme 

caution and maintain a safe distance 

from construction equipment. 

(6) Zone 6, Willoughby Bay Bridge. 

(i) Location: All waters, from surface 

to bottom, located along the Willoughby 

Bay Bridge highway trestle and 

extending 50 feet to the north side of the 

bridge and 300 feet to the south side of 

the bridge along the length of the 

highway trestle, from shore to shore 

within the City of Norfolk. 

(ii) Requirements: No vessel or person 

may enter or remain in the safety zone 

without permission of the COTP, HRCP, 

or designated representative, except that 

vessels are allowed to transit through 

marked safe transit corridors that HRCP 

shall establish for the purpose of 

providing navigation access for 

residents located north of the 

Willoughby Bay Bridge through the 

safety zone. All mariners attempting to 

enter or depart residences or 

commercial facilities north of the 

Willoughby Bay Bridge through the safe 

transit corridors or other areas of the 

safety zone when granted permission 

shall proceed with caution and maintain 

a safe distance from construction 

equipment. 

(c) General requirements. (1) Under 

the general safety zone regulations in 

subpart C of this part, no vessel or 

person may enter or remain in any 

safety zone described in paragraph (b) of 

this section unless authorized by the 

COTP, HRCP, or designated 

representative. If a vessel or person is 

notified by the COTP, HRCP, or 

designated representative that they have 

entered one of these safety zones 

without permission, they are required to 

immediately leave in a safe manner 

following the directions given. 

(2) Mariners requesting to transit any 

of these safety zones must first contact 

the HRCP designated representative, the 

on-site foreman, via VHF–FM channels 

13 and 16. If permission is granted, 

mariners must proceed at their own risk 

and strictly observe any and all 

instructions provided by the COTP, 

HRCP, or designated representative to 

the mariner regarding the conditions of 

entry to and exit from any location 

within the fixed safety zones. 

(d) Enforcement. The Sector Virginia 

COTP may enforce this regulation and 

may be assisted by any Federal, state, 

county, or municipal law enforcement 

agency. 

Dated: July 15, 2021. 

Samson C. Stevens, 

Captain, U.S. Coast Guard, Captain of the 

Port Virginia. 

[FR Doc. 2021–16198 Filed 8–4–21; 8:45 am] 

BILLING CODE 9110–04–P 

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). 


khammond on DSKJM1Z7X2PROD with PROPOSALS
Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Proposed Rules 42763 

1 49 CFR 575.104. 

2 49 CFR 571.105, 571.121, 571.122, 571.126, 

571.135, 571.136, 571.139, 571.500. 

3 60 FR 6411, 6415–17 (Feb. 2, 1995). 

4Another 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). 

5ASTM 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. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

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. 

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 antilock 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. 

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

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 


khammond on DSKJM1Z7X2PROD with PROPOSALS
42764 Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Proposed Rules 

6See 71 FR 877, 880 (Jan. 6, 2006). 

7See 65 FR 33481 (May 24, 2000). 

8See ‘‘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). 

9See ‘‘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-astmspecification-presents-requirements-standardreference-test-tire (last accessed April 13, 2021). 10See Docket No. NHTSA–2020–0067. 

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

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. 

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. 

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. 

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

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. 


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Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Proposed Rules 42765 

11See docket No. NHTSA–2020–0067. 

12NHTSA 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. 

13Although FMVSS No. 500 specifies a PFC value 

for the test surface, the test surface is only used to 

verify the vehicle’s maximum speed. 

14Available at https://www.astm.org/COMMIT/ 

2019_04_10_E1136%20to%20

F2493%20transition%20for%20ASTMF1805.pdf 

(last accessed April 13, 2021). 

15See https://www.ustires.org/sites/default/files/ 

USTMA_TISB_37_0.pdf (last accessed April 13, 

2021). 

16The surface types are defined in the text of 

ASTM F1805. 

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. 

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. 

FMVSS section PFC value using 

14-inch SRTT 

PFC value using 

16-inch SRTT 

FMVSS No. 105 S6.9.2(a) (high friction testing) ............................................................................................. 0.9 1.02 

FMVSS No. 105 S6.9.2(b) (low friction testing) .............................................................................................. 0.5 0.55 

FMVSS No. 121 S5.3.1.1, S5.7.1, S6.1.7 (high friction testing) 12 ................................................................. 0.9 1.02 

FMVSS No. 121 S5.3.6.1, S6.1.7 (low friction testing) ................................................................................... 0.5 0.55 

FMVSS No. 122 S6.1.1.1 (high friction testing) .............................................................................................. 0.9 1.02 

FMVSS No. 122 S6.1.1.2 (low friction testing) ............................................................................................... ≤0.45 ≤0.50 

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, S7.5.2, S7.6.2, S7.7.3, S7.8.2, S7.9.2, S7.10.3, S7.11.3 .......................... 0.9 1.02 

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. 

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. 

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. 


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42766 Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Proposed Rules 

17Michelin presentation; UTQG Wear Change 

from 14′′ TO 16′′ SRTT First Two Test Quarters. See 

docket No. NHTSA–2020–0067. 

139 does not specify the surface type 

specified within ASTM F1805 for 

testing. 

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 snowcovered 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. 

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 

14-inch SRTT 

BCWR data 

16-inch SRTT 

BCWR data 

Quarterly 

published 

BCWR rate 

Theoretical 

16-inch 

SRTT BCWR rate 

Derived 

conversion 

factor based on 

prior 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 


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18The first equation definition P is set forth in 49 

CFR 57.104(e)(2)(ix)(F). 

TABLE 1—QUARTERLY BCWR DATA SINCE APRIL 2016—Continued 

14-inch SRTT 

BCWR data 

16-inch SRTT 

BCWR data 

Quarterly 

published 

BCWR rate 

Theoretical 

16-inch 

SRTT BCWR rate 

Derived 

conversion 

factor based on 

prior six 

quarters 

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

BILLING CODE 4910–59–P 

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 § 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 

§ 575.104(e)(2)(ix)(C) that the CMT must 


khammond on DSKJM1Z7X2PROD with PROPOSALSEP05AU21.038</GPH>

Projected mileage x base course wear rate14 P=------------------- 402 

Projected mileage x base course wear rate16 (base course wear rate14) P=---------------x 

402 base course wear rate16 

base course wear rate14 Conversion Factor = ----------= 1.324 base course wear rate16 

Projected mileage x base course wear rate 

P = ---------------x 1.324 

402 

Projected mileage x base course wear rate P=------------------- 304 
42768 Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Proposed Rules 

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 climatecontrolled 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 


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Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Proposed Rules 42769 

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%20

Procedure.pdf. (last accessed April 13, 2021). 

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-businessinformation 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 online 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. 

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 


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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 nonidentical 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 


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

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 Snowand Ice-Covered Surfaces.’’ ASTM 

F1805 is a test method for measuring the 

traction of tires on snow- or ice-covered 

surfaces using an instrumented fourwheel 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. 

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 


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(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 

■ 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. 

■ 2. Amend § 571.5 by revising 

paragraphs (d)(33) through (35) to read 

as follows: 

§ 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 

§§ 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 Snowand Ice-Covered Surfaces,’’ approved 

May 1, 2020, into § 571.139. 

(35) ASTM F2493–19, ‘‘Standard 

Specification for P225/60R16 97S Radial 

Standard Reference Test Tire,’’ 

approved Oct. 1, 2019, into §§ 571.105; 

571.121; 571.122; 571.126; 571.135; 

571.136; 571.139; 571.500. 

* * * * * 

■ 3. Amend § 571.105 by removing 

paragraphs S6.9.2(a) and S6.9.2(b) and 

adding paragraph S6.9.2 to read as 

follows: 

§ 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 § 571.5), 

standard reference test tire, in 

accordance with ASTM E1337–19 

(incorporated by reference, see § 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. 

* * * * * 

■ 4. Amend § 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: 

§ 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 § 571.5) standard 

reference tire, in accordance with ASTM 

E1337–19 (incorporated by reference, 

see § 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 trucktractor 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 § 571.5)) in accordance 

with ASTM E1337–19 (incorporated by 

reference, see § 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

Truck tractors 

Single unit 

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 (S5.3.1) .................................................................................................... 5 2 

60 mph Emergency Service Brake Stops at GVWR (S5.7.1) ................................................................................. N/A 3 


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TABLE I—STOPPING SEQUENCE—Continued 

Truck tractors 

Single unit 

trucks and 

buses 

Parking Brake Test at GVWR (S5.6) ...................................................................................................................... 6 4 

Manual Adjustment of Brakes ................................................................................................................................. 7 6 

60 mph Service Brake Stops at LLVW (S5.3.1) ..................................................................................................... 8 7 

60 mph Emergency Service Brake Stops at LLVW (S5.7.1) .................................................................................. 9 8 

Parking Brake Test at LLVW (S5.6) ........................................................................................................................ 10 9 

Final Inspection ........................................................................................................................................................ 11 10 

TABLE II—STOPPING DISTANCE IN FEET

Vehicle speed in miles per 

hour 

Service brake Emergency brake 

(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 

Vehicle speed in miles per hour 

Service Brake Emergency Brake 

(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. 

* * * * * 

■ 5. Amend § 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: 

§ 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 highfriction surface has a peak braking 

coefficient (PBC) of 1.02. 

S6.1.1.2 Low-friction surface. A lowfriction 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 § 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. 

* * * * * 

■ 6. Amend § 571.126 by revising 

paragraph S6.2.2 to read as follows: 

§ 571.126 Standard No. 126; Electronic 

stability control systems for light vehicles. 

* * * * * 


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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 § 571.5) standard reference test tire, 

in accordance with ASTM E1337–19 

(incorporated by reference, see § 571.5) 

at a speed of 64.4 km/h (40 mph), 

without water delivery. 

* * * * * 

■ 7. Amend § 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: 

§ 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 § 571.5) 

standard reference test tire, in 

accordance with ASTM E1337–19 

(incorporated by reference, see § 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. 

* * * * * 

■ 8. Amend § 571.136 by revising 

paragraph S6.2.2 to read as follows: 

§ 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 § 571.5). 

* * * * * 

■ 9. Amend § 571.139 by revising the 

definition of ‘‘Snow tire’’ in S3 to read 

as follows: 

§ 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 § 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 § 571.5), and that is 

marked with an Alpine Symbol 

specified in S5.5(i) on at least one 

sidewall. 

* * * * * 

■ 10. Amend § 571.500 by revising 

paragraph S6.2.1 to read as follows: 

§ 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 § 571.5). 

* * * * * 

PART 575—CONSUMER 

INFORMATION 

■ 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. 

■ 12. Amend § 575.3 by revising 

paragraph (c) to read as follows: 

§ 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 

§§ 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 § 575.104. 

* * * * * 

■ 13. Amend § 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: 

§ 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 


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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: 

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 § 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: 

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 


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(Yl -Yo) 

m = 1000 (Xl _ Xo) 

Projected mileage x base course wear raten 

p = 304