Consumer Information Regulations: Uniform Tire Quality Grading Standards

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

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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) BCWRm = BCWRn x [(wear rate of fresh CMT)/

(wear rate of aged CMT)]m-n

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)](10)

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

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Wear rate @

Manufacture date Test start date 6,400 miles

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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

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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.

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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]

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Phase I Phase II

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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

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Projected From Linear Regression at 6,400 Miles

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47,100..... 45,532 42,693 55,900 72,800 46,650 42,825 32,500 32,500

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Projected From Linear Regression at 12,800 Miles

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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%)

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Projected From Linear Regression at 19,200 Miles

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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%)

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Projected From Linear Regression at 25,600 Miles

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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%)

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Projected From Linear Regression at 32,000 Miles

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52,880..... 55,902 64,995

(112%)..... (100%) (89.2%)

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Projected From Linear Regression at 38,400 Miles

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54,690..... 58,219 68,513

(116%)..... (104%) (94.1%)

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Projected From Linear Regression at 44,800 Miles

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56,598..... 60,018 69,766

(120%)..... (107%) (95.8%)

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Projected From Linear Regression at 51,200 Miles

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58,190..... 61,190 70,562

(123%)..... (109%) (96.9%)

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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.

1 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.

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\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.

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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 BCWRn/30,000 x 1.34

Where BCWRn = New BCWR, i.e. average treadwear of last 4

quarterly CMT tests done by NHTSA

or

P = projected mileage x BCWRn/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 raten/402

Where base wear raten = 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