[Federal Register Volume 63, Number 108 (Friday, June 5, 1998)]
[Proposed Rules]
[Pages 30695-30700]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-14109]



[[Page 30695]]

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 575

[Docket No. 98-3866]
RIN 2127-AG96


Consumer Information Regulations: Uniform Tire Quality Grading 
Standards

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

ACTION: Notice of proposed rulemaking.

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SUMMARY: This notice of proposed rulemaking (NPRM) proposes to amend 
the treadwear testing procedures under the Uniform Tire Quality Grading 
Standards (UTQGS). To ensure the consistency of the treadwear grades 
from one year to the next, the agency must monitor the changing 
roughness of the test course, periodically calculate a base course wear 
rate (BCWR), and adjust measured tire wear rates accordingly. To 
monitor the test course, the agency uses special tires designated as 
course monitoring tires (CMTs).
    The agency is proposing to change the computation of the BCWR used 
in calculating the treadwear grade of passenger car tires. Under the 
proposed amendments, there would be a direct comparison of the wear 
rates of course monitoring tires (CMT) used as the control standard and 
candidate tires, i.e, the tires being tested for the purposes of 
grading. This direct comparison would result in more consistent 
treadwear ratings by compensating for any changes or variations in CMT 
characteristics. NHTSA proposes to measure the wear rate of CMTs 4 
times per year and using the average wear rate from the last 4 
quarterly CMT tests as a basis for the BCWR. NHTSA further proposes to 
require, subject to the exception in the following sentence, that CMTs 
used to determine wear rate be no more than 6 months old at the 
commencement of the test and that the difference in the production 
dates of those tires be not greater than 3 months. If tires more than 6 
months old are used in the wear rate test, their average wear rate must 
be reduced by 10 percent.

DATES: Comment closing date: Comments on this notice must be received 
on or before August 4, 1998.
    Proposed effective date: If adopted, the amendments proposed in 
this notice would become effective 60 days after the date of 
publication of the final rule in the Federal Register.

ADDRESSES: Comments should refer to the docket and notice numbers noted 
above for this rule and be submitted to: Docket Management, Room PL-
401, 400 Seventh Street SW, Washington, DC 20590. Docket room hours are 
from 10:00 a.m. to 5:00 p.m., Monday through Friday.

FOR FURTHER INFORMATION CONTACT: For technical issues: Mr. Orron Kee, 
Chief, Consumer Programs Division, Office of Planning and Consumer 
Programs, National Highway Traffic Safety Administration, 400 Seventh 
Street SW, Room 5320F, Washington, DC 20590; telephone (202) 366-0846; 
FAX (202) 493-2739.
    For legal issues: Mr. Walter K. Myers, Office of the Chief Counsel, 
National Highway Traffic Safety Administration, 400 Seventh Street SW, 
Room 5219, Washington, DC 20590; telephone (202) 366-2992; FAX (202) 
366-3820.

SUPPLEMENTARY INFORMATION:

a. Background

    Current Provisions. Section 30123(e) of Title 49, United States 
Code requires the Secretary of Transportation to prescribe a uniform 
system for grading motor vehicle tires to assist consumers in making 
informed choices when purchasing tires. Pursuant to that congressional 
mandate, NHTSA promulgated the Uniform Tire Quality Grading Standards 
(UTQGS) in 49 CFR 575.104.
    The UTQGS require tire manufacturers and tire brand name owners to 
test and grade their tires with respect to their relative treadwear, 
traction, and temperature resistance performance. Treadwear grades are 
shown by numbers, such as 100, 160, and 200, while the traction grade 
is indicated by AA, A, B, and C, with AA representing the highest 
performance characteristics and C the lowest. The temperature 
resistance grade is indicated by the letters A, B, and C, with A 
representing the best performance and C indicating the minimum level of 
performance necessary to comply with Federal motor vehicle safety 
standards.
    Treadwear grades are developed first by running the tires being 
graded, called ``candidate tires,'' over a selected 400-mile segment of 
public highway near San Angelo, Texas. After an 800-mile ``break-in'' 
run, the candidate tires are driven over the test course for a total of 
6,400 miles in test convoys composed of 4 passenger cars and/or light 
truck vehicles. Each driver remains in the same position within the 
convoy. The vehicles are rotated among the 4 positions in the convoy 
regularly as are the positions of the tires on the test vehicles so 
that the tires get equal time with each driver, each vehicle, and each 
wheel position.
    Special tires known as ``course monitoring tires'' (CMT) are used 
as the control in grading candidate tires. CMTs are specially designed 
and built to American Society for Testing and Materials (ASTM) standard 
E1136 to have particularly narrow limits of variability. Until the 
amendments to the UTQGS published in a final rule on September 9, 1996 
(61 FR 4737), whenever NHTSA procured a new batch, or lot, of CMTs, the 
agency established a new BCWR for that lot. The BCWR, measured in mils 
per thousand miles, was established by running tires from the new lot 
of CMTs over the 6,400-mile test course, in the same manner as 
candidate tires, with tires from the previous batch of CMTs. A course 
severity adjustment factor (CSAF) for the CMTs was determined by 
dividing the BCWR for the old CMTs by the average wear rate of the old 
CMTs in the test. The wear rate of the new CMTs was then multiplied by 
the CSAF to determine the adjusted wear rate (AWR) of the new CMTs. 
That value then became the BCWR for the new CMTs.
    Once the BCWR for the new CMTs was established, these CMTs were 
used to grade candidate tires. Upon completion of the 6,400-mile test, 
the BCWR was divided by the average wear rate of the CMTs to determine 
the CSAF for the candidate tires. That factor was then applied to the 
wear rates of the candidate tires to obtain the AWR of the candidate 
tires. That AWR was then extrapolated to the point of wearout 
(considered to be \1/16\th inch of remaining tread depth). The 
resultant value was then converted to the treadwear rating of the tire.
    The BCWR was originally intended to provide a common baseline by 
which to grade candidate tires by relating all new CMTs to the original 
lot of CMTs. However, NHTSA noted that the BCWRs of successive new lots 
of CMTs steadily declined over the years. The trend has been that every 
time that a fresh CMT of the next lot was tested in the same convoy 
with an example of the old CMT from storage, the fresh CMT consistently 
experienced a lower wear rate than the old CMT running in the same 
convoy. The first lot of CMTs procured by the agency in 1975 were 
commercially-available Goodyear Custom Steelguards which yielded a BCWR 
of 4.44. The lot procured by the agency in 1995 produced a BCWR of 
1.34. Table I shows the consistent decline in each new lot of CMTs.

[[Page 30696]]



                                          Table I.--CMT Wear Rate and Base Course Wear Rate Adjustment Factors                                          
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                                                                                                       Measured                  Adj. wear              
                     Year                                    Manufacturer                  Series     wear rate       CSAF          rate         BCWR   
--------------------------------------------------------------------------------------------------------------------------------------------------------
1975..........................................  Goodyear..............................        (\1\)         4.44          1.0          4.44         4.44
1979..........................................  Goodyear..............................        (\1\)         4.08          1.09         4.44  ...........
1979..........................................  Goodyear..............................        (\2\)         3.82          1.09         4.16         4.16
1980..........................................  Goodyear..............................        (\2\)         5.29          0.79         4.16  ...........
1980..........................................  Goodyear..............................        (\3\)         4.76          0.79         3.74         3.74
1984..........................................  Goodyear..............................        (\3\)         4.22          0.89         3.74  ...........
1984..........................................  Uniroyal..............................         4000         3.27          0.89         2.90         2.90
1987..........................................  Uniroyal..............................         4000         5.96          0.49         2.90  ...........
1987..........................................  Uniroyal..............................        71000         4.56          0.49         2.22         2.22
1989..........................................  Uniroyal..............................        71000         5.01          0.44         2.22  ...........
1989..........................................  Uniroyal..............................        91000         4.84          0.44         2.14         2.14
1991..........................................  Uniroyal..............................        91000         6.24          0.34         2.14  ...........
1991..........................................  ASTM E1136............................       010000         4.94          0.34         1.70         1.70
1991..........................................  ASTM E1136............................       010000         6.96          0.24         1.70  ...........
1992..........................................  ASTM E1136............................       110000         6.65          0.24         1.62         1.62
1992..........................................  ASTM E1136............................       110000         5.83          0.28         1.62  ...........
1992..........................................  ASTM E1136............................       210000         5.60          0.28         1.56         1.56
1993..........................................  ASTM E1136............................       210000         7.21          0.22         1.56  ...........
1993..........................................  ASTM E1136............................       310000         68.0          0.22         1.47         1.47
1995..........................................  ASTM E1136............................       310000         6.47          0.23         1.47  ...........
1995..........................................  ASTM E1136............................       410000         5.91          0.23         1.34         1.34
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\1\ Batch 1.                                                                                                                                            
\2\ Batch 2.                                                                                                                                            
\3\ Batch 3.                                                                                                                                            

    In replacing CMTs from the original lot of CMTs procured in 1975, 
it should be noted that the greatest difference in the AWR between 
nominally identical CMTs of different ages was about 30 percent 
occurring in 1987 when the old CMTs had been stored for about 3 years. 
On the other hand, the least difference in the AWR between nominally 
identical CMTs of different ages was about 4 percent occurring in the 
second 1992 replacement when the old CMT had been stored less than a 
year. Table I also shows that the treadwear rate disadvantage of the 
aged CMTs at replacement varied considerably from a linear relationship 
with age. Presumably, therefore, the rate may be exacerbated by actual 
batch differences of the commercial tires used as CMTs prior to 1991.
    The significance of the decrease in the BCWR rate was that as the 
BCWR decreased, the treadwear grades of candidate tires increased. 
Consequently, the newer treadwear grades have increased to the point 
that they have become a misleading indicator of actual tread life when 
compared to tires tested with higher BCWRs.
    To correct this problem, the agency froze the BCWR at 1.34 mils in 
the final rule of September 9, 1996. The agency believed that freezing 
the BCWR at that figure would significantly reduce, if not eliminate, 
any variation in the grading between lots. Further, the agency believed 
that the use of ASTM E1136 tires that are produced with strict quality 
control would also contribute to reduction of any lot-to-lot 
variations. NHTSA stated, however, that it had requested the assistance 
of the ASTM F9 committee in devising a better treadwear test and that 
it would request data in a future rulemaking on the effects of tire 
aging on treadwear performance and storage procedures to reduce aging.

b. Discussion

    The previous computations of the BCWR as described above were based 
on the unstated assumption that the tires in a lot of CMTs were not 
affected by aging. Thus, it was assumed that the last-remaining old 
CMTs in storage were identical in inherent treadwear performance to the 
first tires of the same lot whose treadwear rates were measured when 
they were fresh. NHTSA now has reason to believe that may not in fact 
be true.
    Treadwear tests of convoys containing tires from the same lines of 
radial, bias and bias-belted tires differing in age by one year are 
discussed in NHTSA research. See Brenner, et al., Establishment and 
Calibration of a Tread Wear Test Course, Tire Science and Technology, 
Vol. 3, No. 3, August 1975, at page 174. The purpose of the tests, 
which included tires partially worn at the beginning of the tests, was 
to confirm that the treadwear characteristics of tires with different 
pre-test histories remained sufficiently linear to permit accurate 
tread life projections after 6,400 miles of testing by comparing their 
tread life after 8,000 miles of testing. The tests concluded that of 
the nominally identical tires, those that had been stored approximately 
one year in unspecified circumstances, presumably at the test course at 
San Angelo, had an 8 to 13 percent shorter tread life than their 
fresher counterparts.
    The strength of an aging effect sufficient to account for all of 
the decline in the BCWR since 1975 may be estimated using the following 
equation in which it is assumed that all differences between CMTs are 
the result of aging:

(1) New BCWR = old BCWR  x  [(measured wear rate of new CMTs)/(measured 
wear rate of old CMTs in convoy)].

This produces a gross estimation that does not take into account the 
different storage lengths of the aged CMTs.
    Equation (2) designates BCWRs of different generations of CMTs with 
subscripts m and n, with subscript of 1 referring to the original 1975 
CMT and a subscript of 11 referring to the latest generation:

(2) BCWR<INF>m</INF> = BCWR<INF>n</INF>  x  [(wear rate of fresh CMT)/
(wear rate of aged CMT)]<SUP>m-n</SUP>

    Let m=11 and n=1 to account for all the observed change in BCWR. 
Therefore:
    1.34 = 4.44  x [(wear rate of fresh CMT)/(wear rate of aged 
CMT)]<SUP>(10)</SUP>

Solving for the wear rate ratio yields:

    [(wear rate of fresh CMT)/(wear rate of aged CMT)] = 0.887 or

[[Page 30697]]

    [wear rate of aged CMT)/(wear rate of fresh CMT)] = 1.127

Thus, an average of 12.7 percent degradation of tread life during an 
average storage period of approximately 2 years would account for 
nearly all the change in BCWR during the existence of the UTQGS 
program. This would be consistent with the earlier agency observations 
of 8 to 13 percent degradation during about 1 year of storage. It 
should be noted, however, that year-to-year variations in BCWR could 
have been affected by actual batch differences and/or real changes in 
treadwear characteristics when the brand and line of tires used as CMTs 
were changed.
    To confirm NHTSA's previous test data, the agency contracted with 
Texas Test Fleet, Inc. to conduct a 52,000 mile test in eight 6,400 
mile cycles between November 7, 1996 and February 28, 1997 under 
guidelines set forth by the agency's Office of Vehicle Safety 
Compliance (see Texas Test Fleet, Critical Evaluation of UTQG Treadwear 
Testing & Methodology, DOT HS 808-701, March 10, 1997). The test was 
conducted on the UTQGS test course near San Angelo, Texas. The 
objective of the test was to determine the real wear rate of CMTs by 
running a tightly-controlled UTQGS specification test to wearout or 
near wearout. The break-in phase sought to include all the rapid 
changing, fast wearing, early wear of the tire and prepare it for a 
constant wear period in which a straight-line wear rate could be 
established from which the mileage could be projected, the effects of 
aging could be measured, and the treadwear grade established. In making 
the treadwear projection, the agency assumed that CMT wear rates during 
the test period may not be truly linear because modern radial tires 
have such a long tread life that the 6,400 mile UTQGS treadwear test 
may involve only 10 percent or less of the tire's tread life.
    A set of 4 ASTM E1136 CMTs manufactured during the 26th week of 
1996 (26-6) was used to run the entire 52,000 miles of the test and 
were designated the control standard for the other tires that started 
at the beginning of the test. Two sets of tires on 2 cars started the 
test and ran half way (26,000 miles). Different tires were installed on 
those 2 cars at the halfway point for the second half of the test, and 
a fifth car was started at the same time with 26-6 controls for the 
remainder of the test. The 26-6 and the 45-5 (45th week, 1995) tires 
were not stored in the San Angelo warehouse as were the 30-5 (30th 
week, 1995) and 09-4 (9th week, 1994) tires, but in a cave in Missouri 
that has a constant temperature. The 26-6 tires used in the second half 
of the test wore more rapidly (7.060 MPTM) than the 26-6 tires used in 
the first half of the test, which wore at 6.364 mils. 09-4 CMTs also 
exhibited a relatively high wear rate of 7.773. The wear rates at 6,400 
miles for the tires used in the test are shown in Table II.

                                Table II                                
------------------------------------------------------------------------
                                                          Wear rate  @  
         Manufacture date            Test start date      6,400 miles   
------------------------------------------------------------------------
26th Week of 1996 (26-6) (Cave)...           11/11/96              6.364
45th Week of 1995 (45-5) (Cave)...           11/11/96              6.547
30th Week of 1995 (30-5) (San                                           
 Angelo)..........................           11/11/96              6.968
09th Week of 1994 (09-4) (San                                           
 Angelo)..........................            1/25/97              7.733
26th Week of 1996 (26-6) (Cave)...            1/25/97              7.060
------------------------------------------------------------------------

The effect on aging on 45-5 (cave), 30-5 (San Angelo), and 09-4 (San 
Angelo) CMT tires compared to the 26-6 (cave) control standard are 
shown in Table III.

                                                                        Table III                                                                       
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                                                               Ave. WR/confidence         Cumul. W.R./        Ave. WR/confidence     Ave. WR/confidence 
               Tires                   Ave. WR/confidence     interval 6,400-12,800   confidence interval      interval 12,800-       interval 19,200-  
                                     interval 0-6,400 miles           miles             to 12,800 miles          19,200 miles           25,600 miles    
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45-5 Cave..........................  3% Higher/0.871.......  6% Higher/0.999.......  5% Higher/0.996......  1.2% Higher/0.714....  1.5% Higher/0.531.   
30-5 SA............................  10% Higher/0.997......  10% Higher/0.999......  10% Higher/0.999.....  5% Higher/0.993......  3.8% Higher/0.927.   
09-4 SA............................  9% Higher/0.998.......  8.5% Higher/0.999.....  8.8% Higher/0.999....  4% Higher/0.93.......  10% Higher/0.999.    
--------------------------------------------------------------------------------------------------------------------------------------------------------

The agency found from this series of tests that compared with the 26-6 
CMTs (19 weeks old), the 45-5 cave-stored tires (34 weeks older than 
the 26-6) displayed about 3 percent higher wear rate at 6,400 miles 
with marginal statistical significance because of scatter of the 26-6 
group. However, those 45-5 tires displayed over 6 percent higher wear 
in the 6,400-12,800 mile interval with high statistical significance 
and 5 percent higher cumulative wear to 12,800 with high statistical 
significance, but the effect diminished for intervals after 12,800 
miles. The 30-5 San Angelo-stored tires (about 1 year older) displayed 
about 10 percent higher wear at 0-6,400 and 6,400-12,800 mile intervals 
with high statistical significance, but the effect reduced to about 5 
percent at the 12,800-19,200 mile interval. Finally, the 09-4 San 
Angelo-stored tires, over 2 years older than 26-6, displayed about 10 
percent higher wear to 25,600 miles with no sign of diminishing.
    The agency concluded from the tests that tires typical of the 
remaining CMTs at batch changeover exhibited about 10 percent greater 
wear rates than reasonably fresh ASTM tires. Thus, the 11 batch 
changeovers with this systemic error could explain most of the BCWR 
variations to date, although some real changes in test pavement and 
control tire properties have undoubtedly occurred. The test also 
revealed that every comparison between a newer tire and an older tire 
favored the newer tire, usually with high statistical significance. 
Further, cave storage appears to have a big advantage over open storage 
considering the 0-6,400 mile interval.
    Previous tire manufacturer suggestions to change the treadwear test 
were based at least in part on the belief that, for modern tires, the 
San Angelo test course is too mild, making the tread wear during the 
6,400 mile test insufficient to make reliable projections to wearout. 
The Texas Test Fleet test established, however, that tread life 
projections for the commercial tires

[[Page 30698]]

based on the usual UTQGS procedure at 6,400 test miles fell within 
about 10 percent of projections made at mileages of up to 25,600 test 
miles and even 52,100 test miles for two of the tested tire lines. 
Therefore, increasing the UTQGS procedure from 6,400 to 26,400 miles 
would not appreciably change any projections. To demonstrate this 
conclusively, the agency would need additional extended testing with a 
variety of commercial tires to make a statistically valid decision on 
whether the 6,400 mile test is adequate. The results of the Texas Test 
Fleet tests, however, would not justify more testing since the 
projections for the four commercial tire lines at higher mileages are 
within 10 percent of the 6,400 mile projections and vary somewhat 
randomly around those projections. The tread life projections at 
different mileages are shown in Table IV.

                                        Table IV.--Tread Life Projections                                       
                                          [% of 6,400 Mile Projections]                                         
----------------------------------------------------------------------------------------------------------------
                            Phase I                                                  Phase II                   
----------------------------------------------------------------------------------------------------------------
  26-6 CMT       45-5                                              26-6 CMT                                     
   (Cave)       (Cave)     30-5  (SA)    Brand A      Brand B       (Cave)    09-4  (SA)    Brand C     Brand D 
----------------------------------------------------------------------------------------------------------------
                                 Projected From Linear Regression at 6,400 Miles                                
----------------------------------------------------------------------------------------------------------------
47,100.....     45,532       42,693       55,900       72,800       46,650      42,825      32,500      32,500  
----------------------------------------------------------------------------------------------------------------
                                 Projected From Linear Regression at 12,800 Miles                               
----------------------------------------------------------------------------------------------------------------
47,026.....     44,420       42,009       51,824       72,127       46,239      42,207      32,510      32,653  
(99.8%)....    (97.5%)      (98.3%)      (92.7%)      (99.0%)      (99.0%)     (98.5%)      (100%)      (100%)  
----------------------------------------------------------------------------------------------------------------
                                Projected From Linear Regression at 19,200 Miles                                
----------------------------------------------------------------------------------------------------------------
47,982.....     46,071       43,847       52,701       68,818       47,833      44,481      33,851      33,747  
(101%).....     (101%)       (102%)      (94.2%)      (94.5%)       (102%)      (103%)      (104%)      (102%)  
----------------------------------------------------------------------------------------------------------------
                                Projected From Linear Regression at 25,600 Miles                                
----------------------------------------------------------------------------------------------------------------
50,300.....     48,419       46,012       54,000       67,200       49,964      46,439      35,169      34,907  
(106%).....     (106%)       (107%)      (96.6%)      (92.3%)       (107%)      (108%)      (108%)      (107%)  
----------------------------------------------------------------------------------------------------------------
                                Projected From Linear Regression at 32,000 Miles                                
----------------------------------------------------------------------------------------------------------------
52,880.....                               55,902       64,995                                                   
(112%).....                               (100%)      (89.2%)                                                   
----------------------------------------------------------------------------------------------------------------
                                Projected From Linear Regression at 38,400 Miles                                
----------------------------------------------------------------------------------------------------------------
54,690.....                               58,219       68,513                                                   
(116%).....                               (104%)      (94.1%)                                                   
----------------------------------------------------------------------------------------------------------------
                                Projected From Linear Regression at 44,800 Miles                                
----------------------------------------------------------------------------------------------------------------
56,598.....                               60,018       69,766                                                   
(120%).....                               (107%)      (95.8%)                                                   
----------------------------------------------------------------------------------------------------------------
                                Projected From Linear Regression at 51,200 Miles                                
----------------------------------------------------------------------------------------------------------------
58,190.....                               61,190       70,562                                                   
(123%).....                               (109%)      (96.9%)                                                   
----------------------------------------------------------------------------------------------------------------

Agency Proposal

    As previously stated, in the final rule of September 9, 1996, NHTSA 
froze the BCWR at 1.34 mils for ASTM E1136 tires used as CMTs. The need 
to consider batch-to-batch variations in CMT properties is greatly 
reduced, if not eliminated, by use of the ASTM E1136 tires which are 
specifically constructed to avoid variations between batches. 
<SUP>1</SUP> The agency believes that any errors introduced by ASTM 
tires would remain randomly distributed and smaller than that for 
commercial tires because of the rigidly-controlled manufacturing 
process. Thus, the use of fresh ASTM tires constructed under a 
controlled procedure effectively eliminates systematic differences 
between lots. They are subject only to random differences which, if 
any, should average to zero over repeated tests.
---------------------------------------------------------------------------

    \1\ The designation E1136 refers to the standard specification 
of materials and construction practices codified by ASTM as suitable 
for control tires for scientific experimentation.
---------------------------------------------------------------------------

    NHTSA believes that the use of a BCWR determined by using fresh 
ASTM tires with aged ASTM tires is inappropriate. Rather, the BCWR 
should reflect the yearly mean wear rate imposed on fresh CMTs by the 
test course pavement and driving conditions. The conclusion that aging 
increases the wear rate of tires implies that comparing the wear rate 
of fresh candidate tires to the wear rate of aged control tires 
inflates the treadwear rating because, as discussed above, CMTs one 
year old have experienced significant degradation in treadwear 
properties. Thus, the use of CMTs no more than 6 months old in test 
convoys should limit systematic effects. The agency believes that fresh 
ASTM tires should be run seasonally, that is, 6,400 miles 4 times per 
year, then define the

[[Page 30699]]

BCWR as the average treadwear rate of the last 4 tests of the E1136 
tires. Thus, the aging effect would be eliminated by using only fresh 
CMTs.
    Finally, NHTSA wants to develop a valid CMT replacement procedure 
in case ASTM tires become subject to changes in ASTM design 
specifications or become unavailable. Such a procedure would also 
enable the agency to test the assumption of batch uniformity of ASTM-
specification tires.
    NHTSA proposes, therefore, that treadwear ratings should be 
determined by using ASTM E1136 CMTs produced not more than 6 months 
prior to the beginning of the test. Further, there should be no more 
than 3 months difference in production dates between those CMTs. If 
CMTs older than 6 months are used, their average wear rate must be 
reduced by 10 percent, based on test experience. This latter option 
permits older tires to be used for the convenience of the tester, but 
not as a means of achieving higher treadwear ratings for candidate 
tires. Finally, the agency further proposes to test fresh CMTs 4 times 
per year over the standard 6,400 mile test course and define the BCWR 
as the average treadwear rate of the last 4 tests of the E1136 tire. 
The BCWR will be updated quarterly.
    To implement the proposals discussed above, the formula for 
determining the UTQGS grade would be changed and the grade (P) of the 
NHTSA nominal treadwear value for each candidate tire computed using 
the following formula:

P = projected mileage  x  100  x  BCWR<INF>n</INF>/30,000  x  1.34
Where BCWR<INF>n</INF> = New BCWR, i.e. average treadwear of last 4 
quarterly CMT tests done by NHTSA

        or
P = projected mileage  x  BCWR<INF>n</INF>/402

This simplified equation eliminates the ``30,000'' figure that is no 
longer accurate as a treadwear mileage estimate after the years of BCWR 
drift. This new grade calculation also preserves the current grade 
numbers to avoid any discontinuity.
    In view of NHTSA's proposals discussed above, it would appear 
unnecessary to restrict manufacturers to NHTSA's storage facility for 
the procurement of CMTs. It would be faster, easier, more efficient, 
and possibly more economical for testers to procure ASTM tires directly 
from the manufacturer. It would benefit NHTSA also by permitting the 
agency to discontinue the practice of warehousing and distributing 
CMTs. To ensure that testers are using CMTs that are less than 6 months 
old, NHTSA personnel at the San Angelo test site will review the 
production dates of CMTs used by testers to verify that test fleets are 
using fresh tires.

Rulemaking Analyses and Notices

a. Executive Order 12866 and DOT Regulatory Policies and Procedures

    This document was not reviewed under Executive Order 12866, 
Regulatory Planning and Review.
    NHTSA has analyzed the impact of this rulemaking action and has 
determined that it is not ``significant'' under the DOT's regulatory 
policies and procedures. This proposed action would change the equation 
for determining the base course wear rate for course monitoring tires 
used in the testing of tires for compliance with the Uniform Tire 
Quality Grading Standards. This proposed action, if finalized, would 
not impose any additional costs on tire manufacturers, distributors, or 
dealers. Rather, it would permit tire manufacturers greater flexibility 
in their testing programs and could result in slightly lower costs by 
permitting them to procure course monitoring tires directly from the 
manufacturer rather than from NHTSA. Further, it could save NHTSA the 
time, trouble, and expense of warehousing such tires and selling them 
to manufacturers for use by the latter in their testing programs. 
Nevertheless, the agency believes that any net cost savings would be 
minimal, therefore not warranting preparation of a full regulatory 
evaluation.

b. Regulatory Flexibility Act

    NHTSA has considered the effects of this rulemaking action under 
the Regulatory Flexibility Act, 5 U.S.C. Sec. 601, et seq. I hereby 
certify that this notice of proposed rulemaking would not have a 
significant impact on a substantial number of small entities.
    The following is the agency's statement providing the factual basis 
for the certification (5 U.S.C. Sec. 605(b)). The amendments proposed 
herein would primarily affect manufacturers of passenger car tires. The 
Small Business Administration (SBA) regulation at 13 CFR part 121 
defines a small business in part as a business entity ``which operates 
primarily within the United States'' (13 CFR 121.105(a)).
    SBA's size standards are organized according to Standard Industrial 
Classification (SIC) codes. SIC code No. 3711, Motor Vehicles and 
Passenger Car Bodies, has a small business size standard of 1,000 or 
fewer employees. SIC code No. 3714, Motor Vehicle Parts and 
Accessories, has a small business size standard of 750 or fewer 
employees.
    The amendments proposed in this rulemaking action merely change the 
testing procedure for and calculation of the treadwear grade under the 
Uniform Tire Quality Grading Standards. The purpose of this new 
procedure is to arrest the treadwear grade inflation that has been 
experienced over the past several years. The amendments, if adopted, 
would possibly require NHTSA to conduct additional testing to determine 
the base course wear rate from which treadwear grades are calculated by 
tire manufacturers. The amendments, however, would not impose any 
additional requirements or burdens on tire manufacturers, the great 
majority of which would not qualify as small businesses under SBA 
guidelines. Thus, the proposed new procedures, if adopted, would not 
result in any increase in costs for tire manufacturers, small 
businesses, or consumers. Accordingly, there will be no significant 
impact on small businesses, small organizations, or small governmental 
units by the amendments proposed herein. Thus, the agency has not 
prepared a preliminary regulatory flexibility analysis.

c. Executive Order No. 12612, Federalism

    NHTSA has analyzed this rulemaking action in accordance with the 
principles and criteria of E.O. 12612 and has determined that this rule 
does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.

d. National Environmental Policy Act

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

e. Paperwork Reduction Act

    In accordance with the Paperwork Reduction Act of 1980, Pub.L. 96-
511, NHTSA states that there are no information collection requirements 
associated with this rulemaking action.

f. Civil Justice Reform.

    The amendments proposed herein would not have any retroactive 
effect. Under 49 U.S.C. 30103(b), whenever a Federal motor vehicle 
safety standard is in effect, a state or political subdivision thereof 
may prescribe or continue in effect a standard applicable to the same 
aspect of performance of a motor vehicle only if the standard is 
identical to the Federal standard. However, the United States 
government, a state or political

[[Page 30700]]

subdivision of a state may prescribe a standard for a motor vehicle or 
motor vehicle equipment obtained for its own use that imposes a higher 
performance requirement than that required by the Federal standard. 
Section 30161 of Title 49, U.S. Code sets forth a procedure for 
judicial review of final rules establishing, amending or revoking 
Federal motor vehicle safety standards. A petition for reconsideration 
or other administrative proceedings is not required before parties may 
file suit in court.

Comments

    Interested persons are invited to submit comments on the amendments 
proposed herein. It is requested but not required that any such 
comments be submitted in duplicate (original and 1 copy).
    Comments must not exceed 15 pages in length (49 CFR 553.21). This 
limitation is intended to encourage commenters to detail their primary 
arguments in concise fashion. Necessary attachments, however, may be 
appended to those comments without regard to the 15-page limit.
    If a commenter wishes to submit certain information under a claim 
of confidentiality, 3 copies of the complete submission, including the 
purportedly confidential business information, should be submitted to 
the Chief Counsel, NHTSA, at the street address noted above, and 1 copy 
from which the purportedly confidential information has been deleted 
should be submitted to Docket Management. A request for confidentiality 
should be accompanied by a cover letter setting forth the information 
called for in 49 CFR Part 512, Confidential Business Information.
    All comments received on or before the close of business on the 
comment closing date indicated above for the proposal will be 
considered, and will be available to the public for examination in the 
docket at the above address both before and after the closing date. To 
the extent possible, comments received after the closing date will be 
considered. Comments received too late for consideration in regard to 
the final rule will be considered as suggestions for further rulemaking 
action. Comments on today's proposal will be available for public 
inspection in the docket. NHTSA will continue to file relevant 
information in the docket after the comment closing date, and it is 
recommended that interested persons continue to monitor the docket for 
new material.
    Those persons desiring to be notified upon receipt of their 
comments in the rule docket should enclose a self-addressed stamped 
postcard in the envelope with their comments. Upon receiving the 
comments, the docket supervisor will return the postcard by mail.

List of Subjects in 49 CFR Part 575

    Consumer information, Labeling, Motor vehicle safety, Motor 
vehicles, Rubber and rubber products, Tires.

    In consideration of the foregoing, 49 CFR part 575 would be amended 
as follows:

PART 575--CONSUMER INFORMATION REGULATIONS

    1. The authority citation for part 575 would continue to read as 
follows:

    Authority: 49 U.S.C. Secs. 322, 30111, 30115, 30117, and 30166; 
delegation of authority at 49 CFR 1.50.

    2. Section 575.104 would be amended by revising paragraph 
(e)(2)(ix)(C) and by revising paragraph (e)(2)(ix)(F) to read as 
follows:


Sec. 575.104  Uniform tire quality grading standards.

* * * * *
    (e) * * *
    (2) * * *
    (ix) * * *
    (C) Determine the course severity adjustment factor by assigning a 
base course wear rate to the course monitoring tires (see note to this 
paragraph) and dividing the rate by the average wear rate for the four 
course monitoring tires.
    Note to paragraph (e)(2)(ix): The base wear rate for the course 
monitoring tires will be obtained by the government by running fresh 
ASTM E1136 course monitoring tires for 6,400 miles over the San Angelo, 
Texas, UTQGS test route 4 times per year, then using the average wear 
rate from the last 4 quarterly tests for the base course wear rate 
calculation. Each new base course wear rate will be filed in the DOT 
Docket Management section. This value will be furnished to the tester 
by the government at the time of the test. The course monitoring tires 
used in a test convoy must be no more than 6 months old at the 
commencement of the test and no more than 3 months different from each 
other in production dates at the commencement of the test. If course 
monitoring tires more than 6 months old are used in the test, their 
calculated average wear rate must be reduced by 10 percent.
* * * * *
    (F) Compute the grade (P) of the NHTSA nominal treadwear value for 
each candidate tire by using the following formula:

P = Projected mileage  x  base wear rate<INF>n</INF>/402
Where base wear rate<INF>n</INF> = new base 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 on May 21, 1998.
L. Robert Shelton,
Associate Administrator for Safety Performance Standards.
[FR Doc. 98-14109 Filed 6-4-98; 8:45 am]
BILLING CODE 4910-59-P