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

Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Proposed RulesNotice of proposed rulemaking(NPRM).ACTION:This document proposesamendments to several Federal motorvehicle safety standards and consumerinformation regulations to update thestandard reference test tire (SRTT) usedtherein. The SRTT is used in thosestandards and regulations as a baselinetire to rate tire treadwear, define snowtires based on traction performance, andevaluate pavement surface friction. Thisproposed rule is necessary because theonly manufacturer of the currentlyreferenced SRTT ceased production ofthe tire. Referencing a new SRTTensures the availability of a test tire fortesting purposes.DATES: Submit comments on or beforeSeptember 7, 2021.ADDRESSES: You may submit commentselectronically to the docket identified inthe heading of this document by visitingthe following website: Federal eRulemaking Portal: Go tohttp://www.regulations.gov. Follow theonline instructions for submittingcomments.Alternatively, you can file commentsusing the following methods: Mail: Docket Management Facility:U.S. Department of Transportation, 1200New Jersey Avenue SE, West BuildingGround Floor, Room W12–140,Washington, DC 20590–0001. Hand Delivery or Courier: WestBuilding Ground Floor, Room W12–140,1200 New Jersey Avenue SE, between 9a.m. and 5 p.m. ET, Monday throughFriday, except Federal holidays. To besure someone is there to help you,please call (202) 366–9826 beforecoming. Fax: (202) 493–2251.Regardless of how you submit yourcomments, you should mention thedocket number identified in the headingof this document.Instructions: For detailed instructionson submitting comments and additionalinformation on the rulemaking process,see the Public Participation heading ofthe Supplementary Information sectionof this document. Note that allcomments received will be postedwithout change to http://www.regulations.gov, including anypersonal information provided. Pleasesee the Privacy Act heading below.Privacy Act: In accordance with 5U.S.C. 553(c), DOT solicits commentsfrom the public to better inform itsrulemaking process. DOT posts thesecomments, without edit, towww.regulations.gov, as described inthe system of records notice, DOT/ALL–14 FDMS, accessible throughkhammond on DSKJM1Z7X2PROD with PROPOSALSSUMMARY:VerDate Sep 11 201416:19 Aug 04, 2021Jkt 253001www.dot.gov/privacy. In order tofacilitate comment tracking andresponse, we encourage commenters toprovide their name, or the name of theirorganization; however, submission ofnames is completely optional. Whetheror not commenters identify themselves,all timely comments will be fullyconsidered. If you wish to providecomments containing proprietary orconfidential information, please contactthe agency for alternate submissioninstructions.Docket: For access to the docket toread background documents orcomments received, go to http://www.regulations.gov. Follow the onlineinstructions for accessing the dockets.FOR FURTHER INFORMATION CONTACT: Youmay contact Hisham Mohamed, Officeof Crash Avoidance Standards, bytelephone at (202) 366–0307 or DavidJasinski, Office of the Chief Counsel, bytelephone at (202) 366–2992. Themailing address of both of these officialsis: National Highway Traffic SafetyAdministration, 1200 New JerseyAvenue SE, Washington, DC 20590.SUPPLEMENTARY INFORMATION:I. BackgroundThis rulemaking addresses thestandard reference test tire (SRTT)manufactured according tospecifications set forth in an ASTMInternational standard, E1136,‘‘Standard Specification for P195/75R14Radial Standard Reference Test Tire’’(14-inch SRTT). The 14-inch SRTT is asize P195/75R14 all-season steel-beltedradial tire. The dimensions, weight,materials, and other physical propertiesof the tire are specified in E1136. Thetire is not intended for general use, butas the name indicates, is used fortesting.The 14-inch SRTT was firstintroduced in the 1980s. The 14-inchSRTT was manufactured by onecompany, Michelin North America, Inc(Michelin) and was sold under itsUniroyal brand. NHTSA uses the 14inch SRTT to evaluate tire treadwearperformance 1 by comparing a candidatetire’s performance to the performance ofthe SRTT in a particular performancetest. NHTSA also uses the 14-inch SRTTto evaluate test surface friction 2 forsafety standards relating to brakingbecause the narrow specifications forthe tire (size, component materials, etc.)ensure consistent, repeatableperformance.NHTSA first incorporated the 14-inchSRTT into the Federal Motor Vehicle1 49CFR 575.104.CFR 571.105, 571.121, 571.122, 571.126,571.135, 571.136, 571.139, 571.500.2 49PO 00000Frm 00016Fmt 4702Sfmt 470242763Safety Standards (FMVSSs) in a 1995rule adopting FMVSS No. 135, the lightvehicle braking standard.3 Previously,NHTSA had used skid number to definethe road test surface in the light vehiclebraking test. Testing a surface todetermine skid number involved usinga locked wheel. However, modern antilock brake systems (ABS) are designedto achieve maximum friction prior to awheel becoming locked and the tireskidding. An anti-lock brake systemprevents wheel lockup by modulating avehicle’s brakes at a point just before thewheels would lock up. Consequently, inthe 1995 final rule, NHTSA adoptedASTM method E1337, ‘‘Standard TestMethod for Determining LongitudinalPeak Braking Coefficient (PBC) of PavedSurfaces Using Standard Reference TestTire,’’ as the means for evaluating testsurfaces.4 ASTM E1337 measures thepeak braking force prior to wheellockup, which corresponds to thebehavior of an anti-lock brake system.ASTM E1337 specifies the use of theE1136 SRTT in order to ensure thatvariability in tire size, material, orconstruction does not affect theevaluation of test surfaces.Over time, the evaluation of a testsurface using the ASTM E1337 testmethod and the E1136 SRTT wasincorporated into the heavy vehiclebraking standards (FMVSS Nos. 105 and121), the light and heavy vehicleelectronic stability control standards(FMVSS Nos. 126 and 136), themotorcycle braking standard (FMVSSNo. 122), and the low-speed vehiclestandard (FMVSS No. 500).5The use of the 14-inch SRTT is alsoincorporated into the definition of a‘‘snow tire’’ in FMVSS No. 139.Specifically, a ‘‘snow tire’’ is defined asa tire that attains a traction index greaterthan or equal to 110 compared to the 14inch SRTT when using the ASTM F1805snow traction test. The ASTM F1805snow traction test measures the drivingtraction of tires while traveling in a3 60FR 6411, 6415–17 (Feb. 2, 1995).reason for adopting the peak brakingforce related to the variability associated withdetermining skid number. That matter wasdiscussed in more detail in NHTSA’s earlierproposals to require heavy vehicles to be equippedwith anti-lock brake systems. See 49 FR 20465 (May14, 1984); 49 FR 28962 (July 17, 1984).5 ASTM E1337 is also incorporated by referenceinto 49 CFR 575.106, which are the provisionsrelated to a new tire consumer informationprogram. However, the test procedures in 49 CFR575.106 are not currently used pending publicationof a proposed and final rule establishing theremaining aspects of the consumer informationprogram. See 75 FR 15893 (Mar. 30, 2010).Therefore, this proposal does not address 49 CFR575.106. In a proposal implementing the remainingaspects of that tire consumer information program,NHTSA would address the issues discussed in thisproposal.4 AnotherE:\FR\FM\05AUP1.SGM05AUP1

42764Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Proposed Ruleskhammond on DSKJM1Z7X2PROD with PROPOSALSstraight line on snow- and ice-coveredsurfaces. Tires that meet the definitionof ‘‘snow tires’’ are subject to lessstringent performance test requirementscompared to other tires subject toFMVSS No. 139.6The SRTT is also used as part of theUniform Tire Quality Grading Standards(UTQGS), an information program toassist consumers in making informeddecisions when purchasing tires. TheUTQGS apply to passenger car tires andrequire motor vehicle and tiremanufacturers and tire brand nameowners to provide consumers withinformation about their tires’ relativeperformance regarding treadwear,traction, and temperature resistance.The 14-inch SRTT is used as part ofthe determination of a tire’s UTQGtreadwear rating. As part of the UTQGtest procedures, treadwear is measuredby running the tires being tested (calledcandidate tires) in convoys over a 400mile course of public roads near SanAngelo, Texas. The performance of tiresover this course can change daily due tovariability in the road surface,temperature, humidity, andprecipitation. To compensate forchanges in condition of the test course,candidate tires are tested concurrentlywith course monitoring tires (CMTs).NHTSA has used the 14-inch SRTT asthe exclusive CMT since 1991. CMTsmust be not more than one year old atthe time of commencement of the testand must be used within two monthsfrom being removed from storage inorder to prevent variability resultingfrom aging of the CMT. Theperformance of the CMT is used todetermine the base course wear rate(BCWR) by running four-vehicleconvoys equipped with 16 CMTs for6,400 miles over the test course fourtimes per year. 7 The wear rate of theCMT over the prior four quarterly CMTtest runs are averaged to calculate theBCWR, which is published in DocketNo. NHTSA–2001–9395. The BCWR isused to determine a course severityadjustment factor, which is applied tothe comparison between the candidatetires and CMTs to determine a tire’srating.II. Proposal To Replace 14-Inch SRTTWith 16-Inch SRTTThis proposal would amend NHTSA’ssafety standards and regulations to nolonger reference the 14-inch SRTT.Because of technological advancementsin the development of tires and thegeneral trend of increasing rim diametersizes since the 1980s, the size and6 See7 See71 FR 877, 880 (Jan. 6, 2006).65 FR 33481 (May 24, 2000).VerDate Sep 11 201416:19 Aug 04, 2021Jkt 253001materials of the 14-inch SRTT are nolonger representative of modern tiressold in the U.S. Further, Michelin hasceased production of the 14-inch SRTTbecause it has become difficult forMichelin to obtain the materialsnecessary to manufacture the SRTT.8Thus, NHTSA seeks to reference adifferent standard reference test tire inthe agency’s safety standards andregulations and to transition seamlesslyto the new tire in the agency’scompliance and consumer informationtest programs.ASTM International has developed anupdated specification for an SRTTdesignated F2493 (16-inch SRTT). The16-inch SRTT is size P225/60R16. The16-inch SRTT is considered to be morerepresentative of current tires because ofits larger size and new material anddesign features that lead to traction thatis more typical of modern passenger cartires.9 To the best of NHTSA’sknowledge, the 16-inch SRTT ismanufactured only by Michelin andsold under its Uniroyal brand.To reference an SRTT that is morerepresentative of tires on the road today,and in consideration of Michelin’sdecision to cease production of the 14inch SRTT, NHTSA has determined thatreplacing the 14-inch SRTT in itsregulations is warranted. The onlysuitable replacement for the 14-inchSRTT that has been suggested toNHTSA is the 16-inch SRTT. However,because the 16-inch SRTT is a largersize and uses more modern design andmaterials, it is likely that the 16-inchSRTT will not perform identically to the14-inch SRTT. Therefore, NHTSA hasbeen cooperating with TransportCanada, Natural Resources Canada,representatives of ASTM Internationalcommittees F09 on tires and E17 onvehicle-pavement systems, the U.S. TireManufacturers Association (includingMichelin, currently the solemanufacturer of SRTTs), and the RubberAssociation of Canada to conducttesting to determine the consequences ofreplacing the 14-inch SRTT with the 16inch SRTT. The results of the testing bythese entities, in addition to NHTSA’sown testing, have substantiallycontributed to this proposal to replace8 See ‘‘Discontinued Tire Will Lead to ASTMStandard Changes’’ (July 30, 2015), available st accessed April 13, 2021).9 See ‘‘New ASTM Specification PresentsRequirements for Standard Reference Test Tire’’(April 1, 2007), available at ference-test-tire (last accessed April 13, 2021).PO 00000Frm 00017Fmt 4702Sfmt 4702the 14-inch SRTT with the 16-inchSRTT.10A. Proposed FMVSS Amendments1. Surface Friction MeasurementAs discussed above, other than fordefining a ‘‘snow tire,’’ NHTSA uses theSRTT in the FMVSSs to define thesurface coefficient of friction for the testsurface for braking and electronicstability control (ESC) standards. Thefriction of the test surface is measuredby the peak braking force prior to wheellockup, which is referred to as a peakfriction coefficient (PFC) or peakbraking coefficient (PBC). For thepurpose of this preamble, NHTSA usesthe term peak friction coefficient orPFC, but the terms are usedinterchangeably in the FMVSS.In the FMVSS, the peak frictioncoefficient of a surface is determinedusing the 1990 version of ASTM E1337test method. The ASTM E1337 testmethod involves mounting the SRTT toa test trailer, bringing the trailer to a testspeed of 40 mph (64 km/h), andapplying the brake to produce themaximum braking force prior to wheellockup.When NHTSA was informed thatproduction of the 14-inch SRTT was tobe discontinued, NHTSA evaluated the16-inch SRTT to determine whether itwould be a suitable replacement.NHTSA carefully considered the effectof the 16-inch SRTT on thedetermination of PFC. NHTSA wasconcerned that the use of the 16-inchSRTT without further changes to theFMVSSs would increase the stringencyof the braking and ESC FMVSSs. Thereason for this was that the differentmaterials used in the 16-inch SRTT andthe increased size of the tire wouldresult in the 16-inch SRTT having bettertraction performance than the 14-inchSRTT. If the 16-inch SRTT hasimproved traction performance relativeto the 14-inch SRTT, then the samesurface would have a higher PFC whentested with the 16-inch SRTT.Alternatively stated, obtaining anidentical PFC value using the 16-inchSRTT would require a road surface withlower friction. Testing braking systemsusing stopping distance on road surfaceswith lower friction would requireimproved braking performance to stopin the same distance, which is not anoutcome intended by this rulemaking.Consequently, NHTSA sought aconversion factor to evaluate PFC of atest surface using the 16-inch SRTTwithout altering the severity of anybraking or ESC FMVSSs.10 SeeE:\FR\FM\05AUP1.SGMDocket No. NHTSA–2020–0067.05AUP1

Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Proposed RulesInitial testing confirmed theassumption that using the 16-inch SRTTresulted in a test surface having a higherPFC than when evaluated using the 14inch SRTT. Transportation ResearchCenter, Inc. (TRC) conducted initialtesting in support of the ASTMcommittee evaluating this issue (theE17.21 committee).11 Testing wasconducted on 15 different surfaces ofvarying friction. The evaluation of a drytest surface (e.g., 0.9 PFC using the 14inch SRTT) using the 16-inch SRTTresulted in a PFC over 15 percent higherthan the PFC derived using the 14-inchSRTT. However, testing on a lowfriction surface (0.5 PFC using the 14inch SRTT) showed that the PFCderived using the 16-inch SRTT and the14-inch SRTT was similar.Because the difference in performancebetween the 16-inch SRTT and the 14inch SRTT was not consistent for alllevels of surface friction, somethingmore than a simple multiplier isnecessary to correlate performancebetween the two tires. ASTMInternational has developed such aformula. That formula is included in the2019 update to ASTM E1337, whichNHTSA is proposing to incorporate byreference into the FMVSSs, in place ofthe 1990 version of E1337 currentlyreferenced. NHTSA has used theformula in the 2019 version of E1337 toderive PFC value for all of the FMVSSs.Those values are listed in the tablebelow.Each value derived using the formulawas rounded to the hundredthsposition, rounding up if necessary. Thisensures that the updated FMVSS testsurface PFC specification will be nomore stringent as a result of thisproposed amendment than it is now,consistent with NHTSA’s intent in thisrulemaking.FMVSS ond on DSKJM1Z7X2PROD with PROPOSALSPFC value using14-inch SRTTPFC value using16-inch SRTT0.90.50.90.50.9 0.45 0.80.90.90.90.91.020.551.020.551.02 0.50 0.901.021.021.021.02105 S6.9.2(a) (high friction testing) .105 S6.9.2(b) (low friction testing) .121 S5.3.1.1, S5.7.1, S6.1.7 (high friction testing) 12 .121 S5.3.6.1, S6.1.7 (low friction testing) .122 S6.1.1.1 (high friction testing) .122 S6.1.1.2 (low friction testing) .122 S6.9.7.1 .126 S6.2.2 .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 .136 .500 13 .NHTSA commissioned confirmatorytesting using the 16-inch SRTT to verifythat the PFC values discussed above areequivalent to the PFC values in theFMVSSs derived using the 14-inchSRTT. NHTSA has contracted with TRCto conduct this testing on five differenttest surfaces (wet ceramic, wet jennite,wet asphalt, dry asphalt, and drybroomed concrete). These test surfacesrange from high to low PFC values. Foreach test surface, 10 of each of the 14inch SRTT and the 16-inch SRTT wereeach tested 3 times with 10 stops pertest, for a total of 300 tests for each sizeSRTT on each test surface. A final reportsummarizing the results has been placedin the docket identified at the beginningof this NPRM.2. Snow Tire DefinitionPresently, for a manufacturer todesignate a tire as a ‘‘snow tire,’’ the tiremust attain a traction index equal to orgreater than 110 compared to the 14inch SRTT when tested using the snowtraction test in the 2000 version ofASTM F1805. The ASTM F09committee on tires commissioned astudy to determine the feasibility of11 Seedocket No. NHTSA–2020–0067.is also proposing to revise Tables I, II,and IIA in FMVSS No. 121 to eliminate theredundant references to PFC values in those tables.In place of PFC values, NHTSA is proposing toinclude in Table I (Stopping Sequence) references12 NHTSAVerDate Sep 11 201416:19 Aug 04, 2021Jkt 25300142765replacing the 14-inch SRTT with the 16inch SRTT in the determination ofwhether a tire meets the definition of‘‘snow tire.’’ This study was funded bythe United States Tire ManufacturersAssociation (USTMA).The study consisted of testing oftraction during the winter test seasonsof 2016, 2017, and 2018 to develop amethod to correlate results of testsconducted using the 16-inch SRTT withthose conducted using the 14-inchSRTT. ASTM International haspublished a technical reportdocumenting this work.14 ASTMInternational determined that acorrelation factor of 0.9876 wasappropriate, meaning that a tire thatattained a rating of 110 when testedusing the 14-inch SRTT correlated to arating of 111.4 or 111.5 when testedusing the 16-inch SRTT, depending onthe number of significant digitsconsidered. Recent guidance issued bythe USTMA, a trade associationconsisting of companies thatmanufacture tires in the United States,recommends a minimum traction indexof 112 using the 16-inch SRTT.15Accordingly, NHTSA is proposing toamend the definition of ‘‘snow tire’’ inFMVSS No. 139 to specify that a snowtire is a tire that attains a traction indexof 112 when tested using the updatedF1895 test method using the 16-inchSRTT. This proposal is consistent withthe guidance issued by USTMA, whichNHTSA believes reflects a consensuswithin the tire industry on theappropriate traction index for use indetermining what qualifies as a ‘‘snowtire.’’ NHTSA seeks comment on thisproposal.Furthermore, after reviewing thisinformation from the USTMA, NHTSAdetermined that additional clarificationwas necessary to the definition of a‘‘snow tire’’ in FMVSS No. 139. Thelatest (2020) version of ASTM F1805defines the standard test procedure formeasuring traction on ‘‘snow’’ and ‘‘ice’’surfaces. However, there are multiplesurface types in both the ‘‘snow’’ and‘‘ice’’ categories. They include soft pack(new) snow, medium pack snow,medium hard pack snow, hard packsnow, ice—wet, and ice—dry.16 Thedefinition of ‘‘snow tire’’ in FMVSS No.to the sections in which the various procedures areset forth, which is a more helpful reference.13 Although FMVSS No. 500 specifies a PFC valuefor the test surface, the test surface is only used toverify the vehicle’s maximum speed.14 Available at https://www.astm.org/COMMIT/2019 04 10 pdf(last accessed April 13, 2021).15 See https://www.ustires.org/sites/default/files/USTMA TISB 37 0.pdf (last accessed April 13,2021).16 The surface types are defined in the text ofASTM F1805.PO 00000Frm 00018Fmt 4702Sfmt 4702E:\FR\FM\05AUP1.SGM05AUP1

42766Federal Register / Vol. 86, No. 148 / Thursday, August 5, 2021 / Proposed Rules139 does not specify the surface typespecified within ASTM F1805 fortesting.NHTSA interprets that the ‘‘mediumpack snow’’ condition was intended foruse by manufacturers for marketing tiresas ‘‘snow tires.’’ NHTSA seeks commenton whether this assumption is correct.It is the surface type specified for severesnow tires in UNECE Regulation No.117 for determining when use of theAlpine or Three-Peak MountainSnowflake marking that indicates that atire meets the requirements for use insevere snow conditions. Based upon theresearch on the SRTT, the 2020 revisionof ASTM F1805 contains a revisedtractive coefficient range for ‘‘mediumpack snow’’ using the 14-inch SRTTfrom 0.25–0.41 to 0.25–0.38 and adds atractive coefficient range for ‘‘mediumpack snow’’ using the 16-inch SRTT of0.23–0.38.Based on the research by ASTMInternational and USTMA’s recentguidance, NHTSA is proposing toupdate the

Aug 05, 2021 · 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). 4 Another reason for adopting the peak braking force related to the variability associated with determining skid number. Th