[Federal Register Volume 60, Number 100 (Wednesday, May 24, 1995)]
[Proposed Rules]
[Pages 27472-27488]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-12513]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 575
[Docket No. 94-30, Notice 2]
RIN 2127-AF17
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 proposes to amend the Uniform Tire Quality Grading
Standards to:
1. Revise treadwear testing procedures to maintain the base course
wear rate of course monitoring tires at its current value. That
revision should eliminate treadwear grade inflation, reduce testing
expenses, and reduce the adverse environmental consequences of
operating testing convoys;
2. Create a new traction grading category of ``AA'' in addition to
the current traction grades of A, B, and C to differentiate those tires
with the highest traction characteristics from lower performing tires;
3. Replace the temperature resistance grade with a rolling
resistance/fuel economy grade. This change would provide a measure of a
key fuel economy characteristic of tires, and responds to the
President's Climate Change Action Plan.
DATES: Comments on this notice must be received on or before July 10,
1995.
ADDRESSES: Comments should refer to the docket and notice number shown
above and be submitted to Docket Section, National Highway Traffic
Safety Administration, 400 Seventh Street, SW, Room 5111, Washington,
DC 20590. Docket room hours are from 9:30 a.m. to 4 p.m., Monday
through Friday.
FOR FURTHER INFORMATION CONTACT: Mr. Orron Kee, Office of Market
Incentives, Office of the Associate Administrator for Rulemaking,
National Highway Traffic Safety Administration, 400 Seventh Street,
SW., Room 5320, Washington, DC 20590, telephone (202) 366-0846.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Background
II. April 25, 1994 Request for Comments
A. Treadwear
1. Treadwear Test and Calculation Procedures
a. Candidate Tires
b. Course Monitoring Tires
2. Treadwear Grade Inflation
3. Possible Solutions to Treadwear Grade Inflation
B. Traction
1. Traction Test and Calculation Procedures
2. Ability of Traction Grading System to Differentiate Highest
Traction Tires
3. Possible Solutions to Traction Grading Problems
C. Temperature and Rolling Resistance/Fuel Economy
1. Temperature Resistance
2. Rolling Resistance/Fuel Economy
3. Issues Regarding Temperature/Rolling Resistance/Fuel Economy
III. Summary of Public Comments, Agency Decisions, Benefits and
Costs
A. Treadwear
1. Summary of Comments
2. Agency Decision
3. Costs and Benefits
B. Traction
1. Public Comments
2. Agency Decision
3. Costs and Benefits
C. Temperature/Rolling Resistance/Fuel Economy
1. Public Comments
2. Agency Decision
a. Temperature Resistance
b. Rolling Resistance/Fuel Economy
3. Costs and Benefits
D. Leadtime
IV. Rulemaking Analyses and Notices
A. Executive Order 12866 and DOT Regulatory Policies and
Procedures
B. Regulatory Flexibility Act
C. National Environmental Policy Act
D. Federalism
E. Civil Justice Reform
V. Comments
I. Background
49 U.S.C. 30123(e) requires the Secretary of Transportation to
prescribe a uniform system for grading motor vehicle tires to assist
consumers in [[Page 27473]] making informed choices when purchasing
tires. NHTSA implemented this congressional mandate by issuing the
Uniform Tire Quality Grading Standards (UTQGS) (49 CFR Sec. 575.104).
The UTQGS are applicable to most passenger car tires.
The UTQGS require manufacturers to grade their tires for treadwear,
traction, and temperature resistance. Those characteristics were
adopted by NHTSA after an extended process of study, testing, and
public comment. NHTSA believed that those three characteristics
provided the best balance of tire properties that would be the most
meaningful to consumers. Because those three characteristics interact
with each other, however, manufacturers must use care in trying to
improve any particular characteristic since improving one
characteristic could detract from one or both of the other
characteristics. For example, treadwear life could be extended by
adjusting the tire compounds to produce a harder tread. That
adjustment, however, could detract from traction performance. Tread
life could also be extended by adding more rubber compound to the
tread. That addition, however, could increase rolling resistance,
causing greater internal heating. The increased heating could, in turn,
result in temperature buildup and possibly result in tire failure.
II. April 25, 1994 Request for Comments
On April 25, 1994, NHTSA published a Request for Comments in the
Federal Register (59 FR 19686) requesting public comment on possible
improvements to the UTQGS. Specifically, the agency requested comments
on ways to cure a problem of treadwear grade inflation, whether to add
an additional rating category to provide a means of differentiating
tires with the highest traction characteristics, and whether to
commence the grading of tires for rolling resistance. In view of the
complexity of the subject matter of this notice, the agency is
repeating much of the background explanatory discussion in the Request
for Comments.
A. Treadwear
In the Request for Comments, the agency described the testing of
candidate tires, the role played by course monitoring tires in
adjusting the measured wear of candidate tires and the possible sources
of treadwear rating inflation.
1. Treadwear Test and Calculation Procedures
a. Candidate tires. The treadwear grade is considered the most
meaningful of the three grades to the public, but treadwear is also the
most difficult of the three characteristics to grade.
The procedures which NHTSA follows for testing tires for compliance
with the UTQGS are specified in 49 CFR 575.104(e), Treadwear grading
conditions and procedures. NHTSA tests treadwear by running the tires
being tested, called candidate tires, on test vehicles multiple times
over a 400-mile test course on public roads in the vicinity of San
Angelo, Texas. The test vehicles travel in convoys of two or four
passenger cars, light trucks, or multipurpose passenger vehicles, each
with a GVWR of 10,000 pounds or less. To equalize operating conditions,
the drivers are changed at regular intervals, the tires are rotated to
different positions on the vehicles, and the vehicles are rotated to
different positions within the convoy.
Candidate tires are subjected to a 6,400 mile test. At the end of
the test, the total measured wear is multiplied by a factor that
reflects the severity of the environmental conditions during the test
(the purpose and derivation of that factor is explained below in the
discussion of course monitoring tires). The result of the
multiplication is the adjusted wear rate (AWR) of the candidate tires.
The AWR is extrapolated to wearout, which is considered to be the point
at which \1/16\th of an inch of tread remains. The extrapolated figure
becomes the treadwear grade. A grade of 100 indicates that the tire can
be expected to achieve 30,000 miles to wear out, as measured on the San
Angelo course. A treadwear grade of 150 should achieve 50 percent more
mileage than the one graded 100, if tested on the same course and under
the same conditions. NHTSA emphasizes, however, that the treadwear
grades are not meant to be indicative of the actual mileage every
consumer can expect from a given tire. The grades are intended to be
indicators of relative performance rather than absolute performance.
Thus, a tire graded at 150 should achieve 50 percent more mileage than
one graded at 100. The actual tire mileage achieved by a motorist
depends on many variables, such as geographic location, road
conditions, individual driving habits, climate, weather, tire
maintenance, and so forth.
b. Course Monitoring Tires. Environmental factors like changes in
road and climatic conditions can cause course wear rates for the same
tire to vary on a daily basis. In order to compensate for the effect of
such variables on the amount of wear during a particular treadwear
convoy test, candidate tires are tested along with control tires called
course monitoring tires (CMT). Four CMT's are placed on one test
vehicle and four candidate tires with identical size designations are
placed on each other test vehicle in the convoy. CMTs are built to the
specifications of American Society for Testing and Materials (ASTM)
standard E1136, which specifies tight controls over the production,
handling, and storage of those standardized control tires.
Since CMT lots are not precisely identical, even though
manufactured to ASTM standards, a base course wear rate (BCWR) is
established for each new batch or lot of CMTs procured by the agency.
The BCWR is the calculated wear rate of that lot of CMTs under
``average'' conditions and is applied to the CMTs to adjust for the
variability in the wear rates between CMT lots. The BCWR for the new
lot is determined by running tires selected from that lot over the test
course in a convoy along with CMTs from the previous lot. The previous
CMTs are run in an attempt to determine whether and to what extent
there have been changes in the condition of the course. The measure of
those changes is called a course severity adjustment factor (CSAF). The
CSAF is determined by dividing the BCWR for the CMTs by the average
wear rate of the 4 CMTs in the test convoy. It is assumed that any
difference between the BCWR and the wear rate reflects changes in the
course. The measured wear rate of the new CMTs is then multiplied by
the CSAF to obtain the adjusted wear rate (AWR) of the new CMTs, which
then becomes the BCWR for new CMTs. This procedure is intended to make
the BCWR of new CMTs comparable to that of the previous CMTs by
removing changes in the course as a source of difference between the
BCWR of the previous CMTs and that of the new CMTs.
Upon completion of the 6,400-mile test of the candidate tires, the
BCWR of the new CMT lot is divided by the average measured wear rate of
the new CMTs in the test convoy to determine the CSAF for that convoy.
That CSAF is then applied to the wear rates of the candidate tires. The
AWR of the candidate tires is extrapolated to the point of wear out,
which then becomes the treadwear rating of the candidate
tires. [[Page 27474]]
2. Treadwear Grade Inflation
NHTSA has noted significant increases in treadwear ratings since
the UTQGS became fully effective in 1980. Early in the UTQGS program,
the treadwear ratings remained at roughly the same level. As the years
progressed, however, treadwear ratings have drifted steadily upward in
both manufacturers' and NHTSA's testing results. In part, this increase
reflects the fact that current tires are of higher quality, perform
better and last longer than tires produced even a few years ago. Such
improvements result from industry developments such as improvements in
rubber compounds, cord materials, tire designs, and tread
configurations.
The agency believes, however, that some of the increase in
treadwear grades cannot be explained by improvements in tires. A
significant amount of the unexplained increase is traceable to a
decline in the BCWRs of each successive lot of CMTs. Under the formula
for calculating treadwear, the BCWRs for CMTs and treadwear vary
inversely, Thus, as the BCWRs decrease, treadwear increases.
3. Decline in Base Course Wear Rate
Since the first lot of CMTs was procured in 1975, there has been a
steady and consistent decline in the BCWRs of each successive lot of
CMTs. Although measured wear rates for CMTs have varied, BCWRs have
steadily declined from 4.44 mils per thousand miles for the original
lot of CMTs to 1.47 mils per thousand miles for the last lot purchased
in 1993, as shown in Table 1, below:
Table 1.--CMT Wear Rates and Base Course Wear Rate Adjustment Factors
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Wear rate
(mils per
Year tested Manufacturer Series 1,000 BCWR
miles)
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1975........................ Goodyear................... Batch 1.................... 4.44 4.44
1979........................ Goodyear................... Batch 1.................... 4.08
1979........................ Goodyear................... Batch 2.................... 3.82 4.16
1980........................ Goodyear................... Batch 2.................... 5.29
1980........................ Goodyear................... Batch 3.................... 4.76 3.74
1984........................ Goodyear................... Batch 3.................... 4.22
1984........................ Uniroyal................... 40000...................... 3.27 2.89
1987........................ Uniroyal................... 40000...................... 5.96
1987........................ Uniroyal................... 71000...................... 4.56 2.21
1989........................ Uniroyal................... 71000...................... 5.01
1989........................ Uniroyal................... 91000...................... 4.84 2.14
1991........................ Uniroyal................... 91000...................... 6.24
1991........................ ASTM E1136................. 010000..................... 4.94 1.70
1991........................ ASTM E1136................. 010000..................... 6.96
1992........................ ASTM E1136................. 110000..................... 6.65 1.62
1992........................ ASTM E1136................. 110000..................... 5.83
1992........................ ASTM E1136................. 210000..................... 5.60 1.56
1993........................ ASTM E1136................. 210000..................... 7.21
1993........................ ASTM E1136................. 310000..................... 6.80 1.47
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4. Causes of the Decline in BCWRs and Possible Agency Responses
The decline in the BCWRs suggests either that the test course
itself is becoming progressively rougher or that other factors, as yet
unidentified, are responsible, or both. The agency does not believe
that the course has changed to any significant extent. The test course
is well maintained by the State of Texas and presumably has changed
little in severity over the years.
Accordingly, the agency has considered a number of other factors
which could explain the decline, such as effects of aging and storage
on tire performance, errors in the BCWR calculation, or some
combination of those and perhaps other factors. The agency believes
that the decline of the BCWRs may be caused in large part by the aging
of the CMTs themselves while in storage. In addition, since the
decrease in BCWRs has been so consistent with each new lot of CMTs, the
agency believes that the problem may also be caused at least in part by
an as-yet unidentified flaw in the formula for calculating the BCWR.
As tires age, their chemical compounds steadily emit minute amounts
of gases. The rate of emission may be affected by environmental
conditions. Further, environmental conditions, such as extremes of
temperature can directly affect the tires. The combined effect of the
environmental conditions and the emission of gases can cause changes in
the rubber compounds over time. Such changes adversely affect the
resiliency of the rubber, increasing wear rates and giving a false
indication that the test course could be becoming more severe.
To minimize the aging factor, the agency has in recent years
procured CMTs in small lots so as to reduce the interval between
determining the BCWR for a given lot and subsequently using tires from
that lot in determining the BCWR for the next lot. The agency has also
begun to store the CMTs in polyethylene bags in a warehouse in which
the temperature, although not controlled to the extent specified in
ASTM E1136, normally ranges between 60 deg. and 90 deg.. The agency
hopes that by storing the CMTs in the bags they will not be exposed to
the atmosphere, thereby diminishing the gas emissions described above
and lessening the outgas effect on the tires.
With respect to the formula for calculating BCWR, the agency
requested comment on whether the practice of recalculating the BCWR of
each new lot of CMTs should be abandoned and the wear rates of
candidate tires compared directly with those of the CMTs, that is,
without adjusting the wear rate of the new CMTs to reflect differences
(theoretically due to aging) between the wear rates of the new CMTs and
the CMTs from the previous lot. The intent of the BCWR is to provide a
common baseline by which to grade candidate tires. However, NHTSA's
practice of relating all new CMTs to the original CMTs in the manner
specified in the UTQGS has somehow distorted the treadwear grading
procedure to bring about the inflated results now being experienced.
[[Page 27475]]
In asking whether the agency should switch to direct comparison,
the agency sought available data on whether such direct comparison of
the wear rates of CMTs and candidate tires would avoid the effects of
flaws in the current treadwear procedures. The switch to direct
comparison could result in lower, and perhaps more realistic, treadwear
ratings. On the other hand, it could change the original intent of the
CMT, which was to provide a common baseline for comparison of wear
rates, regardless of when a candidate tire was tested. In addition, it
could present a problem for the tires already graded and still in
production by having to re-test and re-grade them.
The agency posed four other questions in the notice, i.e., whether
the current ratings are misleading, whether a new system should be
developed for treadwear grading, whether the test should be changed,
and whether the BCWR computation procedure should be changed.
B. Traction
1. Traction Test and Calculation Procedures
Traction grades are established by sliding tires over test pads
also located near San Angelo, Texas. One pad consists of a wet asphalt
surface; the other, a wet concrete surface. A test trailer is equipped
with two control tires manufactured in accordance with ASTM standard
E501. The control tires are inflated to 24 pounds per square inch
(psi), statically balanced, allowed to cool to ambient temperature with
inflation pressure maintained at 24 psi, then installed on the test
trailer. Each tire is loaded to 1,085 pounds. The trailer is first
towed over the wet asphalt surface at a speed of 40 miles per hour
(mph). As one of the wheels with a control tire passes across the
asphalt, it is locked. The traction coefficient of the locked wheel is
recorded for a period of 0.5 to 1.5 seconds after lockup. The same
procedure is then followed for the same wheel/control tire as the
trailer is towed across the wet concrete surface. These tests are
conducted 10 times on each surface for that wheel/control tire. The
same tests are then conducted for the other wheel/control tire. The 20
measurements taken on each surface are averaged to find the control
tire traction coefficient for that surface. After the testing of the
control tires, those coefficients are used in calculating the traction
coefficients of the candidate tires.
In testing the candidate tires, two tires of the same type,
construction, manufacturer, line, and size designation are prepared and
tested utilizing the same procedures described above for the control
tires. The loads on the candidate tires, however, are maintained at 85
percent of the test loads specified in Sec. 575.104(h). The adjusted
traction coefficients of the candidate tires are determined in
accordance with Sec. 575.104(f)(2)(ix) and (x).
The grades of the candidate tires are designated as ``A'', ``B'',
or ``C.'' A tire that achieves both a high level of traction
performance on asphalt (above 0.47) and a high level on
concrete (above 0.35) is graded ``A.'' A tire achieving medium
traction performance (0.38 on wet asphalt and 0.26 on
wet concrete) is graded ``B.'' A tire achieving traction performance
lower than 0.38 on asphalt and 0.26 on concrete is
graded ``C.''
2. Ability of Traction Grading System to Differentiate Highest Traction
Tires
NHTSA's analysis of traction test data since 1989 indicates that
tire traction performance has improved to the extent that the current
grading system does not adequately differentiate between tires with
different levels of performance, particularly the highest performing
tires.
Another issue being examined by NHTSA is the implication of the
increasing number of vehicles with antilock braking systems (ABS) for
the way in which traction is measured. For non-ABS vehicles, sliding
traction is the primary traction force in panic braking since the
vehicles' wheels are locked during such braking. However, for ABS
vehicles, peak tire traction is the primary traction force since the
ABS keeps the tire rolling during panic braking.
3. Possible Solutions to Traction Grading Problems
The agency solicited comments on whether the traction ratings
should be revised to differentiate the highest performing tires. One
alternative for addressing this problem would be to adjust each grade
category so that it would represent a higher band or range of
performance than it currently does. For example, the A grade could be
adjusted so that it includes tires with traction coefficients above
0.54 on asphalt and above 0.41 on concrete, while a B
rating could include tires with traction coefficients above
0.48 and 0.35 respectively, and a C rating could
include tires with performance below that. Another alternative would be
to make no adjustment in the level of performance represented by the
existing grades, but create a new grade category of ``AA'' for the
highest performing tires, i.e., those tires achieving traction
coefficients above 0.54 and 0.41 respectively.
NHTSA also sought comments on whether to replace or supplement
traction grading based on sliding traction with traction grading based
on peak tire traction and asked about the cost of measuring peak
traction.
C. Temperature and Rolling Resistance/Fuel Economy
1. Temperature Resistance
The current provisions of the UTQGS require grading tires in a
third category, temperature resistance. The temperature resistance
grade indicates the extent to which heat is generated and/or dissipated
by a tire by measuring the ability of the tire to operate at high
speeds without tire failure. Heat is generated by the energy absorbed
by the tire from the friction caused by the flexing and slipping of the
rubber as it rolls along the road. That energy is wasted and appears in
the tire as heat. The more energy that is wasted, the greater the heat
buildup. If the tire is unable to dissipate that heat effectively or if
the tire is unable to resist the heat buildup, its ability to run at
high speeds without failure is reduced. Therefore, its temperature
resistance grade is lower.
Heat buildup is generally caused by some combination of tire
overloading, high speed operation, and/or improper inflation pressure,
all of which contribute to greater flexing and increased heat buildup.
Sustained high temperature can cause structural degeneration of the
tire compounds resulting in reduced tire life or outright tire failure.
NHTSA tests tires for temperature resistance utilizing the same
laboratory test wheel as the high speed performance test of Federal
motor vehicle safety standard (Standard) No. 109, New pneumatic tires.
That test is conducted at speeds up to 85 mph, while the UTQGS
temperature resistance test is run at speeds of up to 115 mph. A tire
is graded ``A'' if it completes the test at a sustained speed of 115
mph without visual evidence of tread, sidewall, ply, cord, innerliner,
or bead separation, chunking, broken cords, cracking or open splices,
and the inflation pressure is not less than the specified test
pressure. A tire is graded ``B'' if it completes the test at speeds
between 100 and 115 mph without the damage mentioned above, and is
graded ``C'' if it has successfully completed the test at speeds
between 85 and 100 mph.
2. Rolling Resistance/Fuel Economy
NHTSA considers temperature resistance to be a valid safety concern
[[Page 27476]] and is unaware of any problems with the accuracy of the
ratings. However, despite the agency's efforts over the years to
educate the public by means of consumer information bulletins, press
releases, and labels affixed to tires explaining the meaning and
significance of the UTQGS ratings, NHTSA has found that most of the
tire-buying public is not aware of and/or does not understand the
significance of the temperature resistance rating.
Conversely, increasing interest has been shown in adding a rating
for rolling resistance on the basis that such a rating could be readily
understood by the public. The possibility of adding such a rating was
discussed at the White House Conference on Global Climate Change on
June 10 and 11, 1993 (hereinafter referred to as the Conference). At a
meeting of the Auto and Light Truck Workshop of the Transportation
Working Group of the Conference, Michelin presented a paper asserting
that the average rolling resistance for original equipment all-season
radial tires was 22.6 percent less than that for typical replacement
tires. Further, it was suggested that a 4 percent improvement in fuel
economy could be realized if replacement tires had the same rolling
resistance as original equipment tires.
As a result of the Conference, the Administration issued a report
on October 19, 1993, entitled The Climate Change Action Plan (Plan),
setting forth a series of initiatives to reduce greenhouse gas
emissions. The Plan calls for reduction of U.S. greenhouse gas
emissions to 1990 levels by the year 2000. One of the initiatives to
accomplish that goal calls for DOT, through NHTSA, to issue new rules
and test procedures requiring manufacturers to test and label tires
relative to their rolling resistance.
NHTSA expressed its belief in the Request for Comments that there
is a close relationship between temperature resistance and rolling
resistance. One of the causes of heat generation in tires, the action
of the tread on the road surface, also causes rolling resistance. In
fact, it is the friction resulting from rolling resistance that is the
immediate cause of heat generation in the tire. Properties of the road
and of tire materials, such as roughness, softness, as well as amount
of flexing, determine the amount of friction and therefore the amount
of heat generated.
Rolling resistance is measured in a procedure similar to that used
for measuring temperature resistance, namely by running a tire under
load on a test wheel. The energy consumed in driving the tire is
measured and the energy recovered from the tire is measured by the test
equipment. The difference is the heat energy lost which is the measure
of the rolling resistance.
Safety benefits should not be lost by substituting rolling
resistance for temperature resistance since the two are related and
determined by similar tests. Standard No. 109 would continue to ensure
that all tires are capable of safe operation at speeds of up to 85 mph,
which establishes a minimum safety threshold. Further, given that the
public is not very responsive to temperature resistance ratings, the
elimination of those ratings should not cause the tire manufacturers to
lower the temperature resistance performance of their tires.
3. Issues Regarding Temperature/Rolling Resistance/Fuel Economy
The agency invited comments on a wide variety of issues relating to
temperature resistance. Among them were whether the rolling resistance
can be improved without detracting from the other rated tire
performance characteristics, whether the temperature resistance rating
should be supplemented by or replaced by a rolling resistance rating,
whether such a substitution would have any safety consequences, and how
rolling resistance values should be translated into improvements in
``real world'' fuel economy.
III. Summary of Public Comments, Agency Decisions and Benefits and
Costs
To preserve the continuity of discussion about each type of UTQGS
rating, the agency presents below, as one unit, the summary of public
comments, the agency decision in response to those comments, and the
costs and benefits of the decision first with respect to the treadwear
rating procedures, then traction, and then temperature/rolling
resistance.
A. Treadwear
1. Summary of Comments
Bridgestone/Firestone, Inc. (BF), The Goodyear Tire and Rubber
Company (Goodyear), General Tire (GT), Michelin, MTS Systems
Corporation (MTS), Dunlop Tire Corporation (Dunlop), Cooper Tire and
Rubber Company (Cooper), and the European Tyre and Rim Technical
Organisation (ETRTO) responded to the agency's treadwear issues. BF,
GT, and Dunlop did not consider the UTQGS treadwear grade misleading to
consumers, so long as the grade is used only to compare tires and not
project expected mileage to wearout. Goodyear, ETRTO, and Michelin, on
the other hand, believed that the treadwear rating is misleading to the
public because the treadwear test produces inconsistent results. They
argued that the inconsistencies arose from such factors as the steady
decline in the BCWR, the relatively short duration of the treadwear
test, and the low wear rates of the tires, which cause the treadwear
test to overestimate tire life. Michelin further commented that
although tire technology has improved considerably in the past few
years, treadwear grades have increased faster than technological
improvements. Michelin commented that the test course is not
sufficiently demanding.
BF, Goodyear, Cooper, and Dunlop commented that the treadwear grade
should be deleted altogether, arguing that it is not needed and is not
cost effective. Goodyear stated that manufacturers' tire warranties are
better and more meaningful to consumers, and BF asserted that NHTSA's
own figures indicate that 70 percent of the tire-buying public pay no
attention to the treadwear grade. Cooper and Dunlop asserted that the
treadwear grade is environmentally unfriendly, Dunlop contending that
every test convoy adds 22 tons of greenhouse gases to the environment
and costs $27,524.64.
Goodyear, Dunlop, Michelin, BF, and MTS commented that if the
treadwear grade remains a part of the UTQGS, a new system should be
developed for rating it. They contended that the present rating system
is too expensive, unreliable, and has too many variables. Goodyear,
Dunlop, and MTS urged development of a standard, repeatable laboratory
test, and BF, Cooper and Dunlop recommended that NHTSA participate with
the ASTM F9 Committee to develop a new indoor, environmentally friendly
test procedure. This refers to a committee of the ASTM, designated the
``F9 Committee,'' which was formed to develop a laboratory test to
assess treadwear potential.
Goodyear, Michelin, BF, and MTS all agreed that the test procedure
should be changed, contending that the vehicle to vehicle rotation of
the candidate tires creates new variables in addition to the existing
ones. Finally, Goodyear, Cooper, Dunlop, BF, and GT recommended that
the BCWR be fixed at its present figure of 1.47 to achieve more
consistent results and save testing costs.
2. Agency Decision
The agency is not persuaded by the commenters' assertions that the
treadwear ratings of tires under the UTQGS are inconsistent and mislead
the public. The agency does not agree that the treadwear test results
are [[Page 27477]] inconsistent. The treadwear grade provides a basis
on which to compare the relative treadwear of tires tested under
controlled conditions. The agency believes that a road test has the
inherent advantage of measuring treadwear rates under actual road
conditions. Further, the computations used in calculating the BCWR,
CSAF, and the AWR are specifically intended to make the treadwear test
results as consistent as possible.
NHTSA does not agree with commenters that suggested that the
practice of vehicle to vehicle rotation of candidate tires creates new
variables and should be changed. On the contrary. NHTSA has found, and
so stated in a previous notice (55 FR 47765) that rotation of the tires
throughout the test convoy significantly reduced the variability of
treadwear grades resulting from test car and driver factors.
NHTSA believes that the treadwear ratings provide consumers with
reliable information on which to distinguish between the relative
performance of the different tire types and brands. They are not
intended to project the actual expected mileage of a tire. Tire
purchasers are specifically advised of this on the label required by 49
CFR 575.104(d)(1)(B)(2), which states that the treadwear rating is a
``comparative rating'' and explains what the rating represents. The
voluntary treadwear warranties provided by manufacturers do, by
contrast, indicate the amount of mileage that can be expected from a
given tire. NHTSA considers the UTQGS treadwear ratings and the
manufacturers' warranties to be complementary and, in many instances,
confirm each other. NHTSA's surveys show that 74 percent of the public
had heard of the treadwear ratings and 29 percent consider such ratings
in making their tire purchases. While 29 percent may seem a
comparatively small percentage of the tire buying public, it is large
enough to be influential. Tire manufacturers continue to make
improvements in treadwear. Further, treadwear related information is
given prominent treatment in tire advertising.
Cooper and Dunlop commented that the treadwear rating should be
deleted because the testing is expensive and ``environmentally
unfriendly.'' Since treadwear is the central feature of the
statutorily-mandated UTQGS, NHTSA is not proposing to delete treadwear.
NHTSA is well aware of the expense of treadwear testing. NHTSA's
contract cost of operating a 4-car test convoy for the 7,200 mile test
(6,400 miles for the test and 800 miles for the pre-test break-in) is
$17,751. Dunlop did not disclose the basis for the $27,524.64 figure it
quoted. Regardless of the per convoy cost, the agency notes that the
per tire cost is minimal, considering that the test cost is averaged
over all the tires produced of the same type. As to greenhouse gas
emissions, NHTSA estimates that the emissions into the atmosphere per
4-car convoy is between 14.08 and 15.8 tons. Again, Dunlop did not
explain how it arrived at the 22-ton figure.
As discussed in section IIA1, Treadwear test and calculation
procedures, above, the agency believes that the primary reason for past
treadwear grade inflation has been the effects of aging on the CMTs
while in storage. The agency believes, however, that wrapping the CMTs
in polyethylene bags and storing them in a warehouse where the
temperature only varies between 60 deg. and 90 deg. is minimizing the
aging effects on the different lots of CMTs.
The agency is persuaded by the suggestions of Goodyear, Cooper,
Dunlop, BF and GT that the BCWR be fixed at its present figure, 1.47
mils per thousand. Maintaining the BCWR at the current figure would
allow existing treadwear ratings to remain essentially unchanged and
prevent future grade creep. Further, the fiscal expense and
environmental effects of running test convoys would be eliminated.
Accordingly, NHTSA proposes to fix the BCWR of all future lots of CMTs
at the current rate of 1.47 mils per thousand, or the value in use on
the date of issuance of any final rule resulting from this proposed
rulemaking action. If the agency issues such a final rule, it would
consider taking the further step of subsequently substituting the BCWR
in use on the effective date of the final rule for the BCWR in use on
the issuance date of the final rule. The agency believes that fixing
the BCWR, in addition to the more strictly controlled storage
procedures, would eliminate or significantly reduce treadwear grade
inflation and reduce costs both to NHTSA and the industry by not having
to test each new lot of CMTs.
3. Costs and Benefits
The agency believes that assigning a fixed value to the BCWR would
reduce to insignificance, if not eliminate entirely, the inflation of
treadwear ratings. The change in storage procedures is internal to
NHTSA and will not result in any costs to tire manufacturers or
consumers. Fixing the BCWR at its present rate also would have no cost
effect on manufacturers or consumers because it involves no additional
testing, retesting or relabeling of tires. The treadwear amendments
would, however, benefit both manufacturers and the public by
simplifying the required treadwear grading of tires and by making the
treadwear grades more realistic and consistent.
B. Traction
1. Public Comments
Goodyear, Dunlop, ETRTO, GT, MTS, and BF recommended maintaining
the current traction rating method. GT and Dunlop stated that changing
the rating system could cause confusion both to consumers and to the
industry, and MTS stated that the current system produces reliable,
repeatable results.
Cooper, on the other hand, recommended changing the rating system,
arguing, without explanation, that the current system is oversimplified
and potentially misleading. Cooper argued further that the traction
numbers generated since NHTSA changed the test pads at San Angelo in
1989 are significantly lower than before the pads were changed and that
therefore there is no need for an additional traction grade level.
Specifically, Cooper cited traction tests conducted on the new skid
pads in 1992 and 1993 on 54 tires of 28 different brands from 12
different manufacturers. Cooper stated that those tests showed an
arithmetic mean of only 0.48.04 for traction coefficients
on the wet asphalt surface and 0.34.02 on the wet concrete
surface. Cooper stated that these figures showed a significantly
different statistical distribution than that cited by NHTSA in support
of the suggestion to upgrade the traction grading system. In addition,
Cooper noted that none of the 54 tires tested would qualify for NHTSA's
suggested ``AA'' traction grade. Finally, Cooper suggested that the
agency work with the ASTM F9 Committee to develop a better test method.
Only Michelin supported the suggestion that the traction grade be
upgraded. Cooper and Dunlop opposed upgrading the traction rating,
arguing that it would confuse the public and increase costs to the
industry with no consequent benefit to consumers. Dunlop stated that
changes to the traction grading scheme would mean most existing tires
and those in production would need to be regraded. Although Goodyear
and ETRTO were not enthusiastic about upgrading the traction category,
they stated that if the traction grade were changed, they favored
creation of the ``AA'' category. MTS agreed that if the traction grade
were changed, ``AA'' would be the simplest and most meaningful change.
[[Page 27478]]
With respect to whether peak traction should be measured and added
to the traction grade, Goodyear, Michelin and MTS expressed support for
the suggestion, saying that peak traction correlates with stopping
distance and the measurements are reliable. Dunlop, Cooper, and BF
opposed the suggestion, however, contending that the majority of motor
vehicles currently on the road are not equipped with ABS. They also
contended that peak traction data are more variable than sliding
traction data and thus not so reliable.
The commenters agreed, however, that the cost of measuring peak
traction would be minimal since both peak and sliding traction values
could be measured under current test procedures, although data
retrieval systems would need to be modified.
2. Agency Decision
NHTSA does not agree with the conclusions that Cooper draws from
its figures regarding the traction coefficients of the new skid pads at
San Angelo. The agency notes that Cooper's figures are based on a
relatively small sample.
NHTSA statistically analyzed larger samples. Its analysis of
traction tests of 254 candidate tires tested on the new skid pads
showed that the distribution of the traction coefficients of the tested
tires had a mean, or average, value of 0.516 on the wet asphalt surface
and 0.364 on the wet concrete surface. The standard deviation about the
mean values of this tire group was 0.029 on the wet asphalt and 0.017
on the concrete surface.
NHTSA's statistical analysis of 196 candidate tires tested on the
old skid pads showed the mean value of the traction coefficients of
those tires to be to be 0.533 on the wet asphalt surface and 0.375 on
the wet concrete surface. The standard deviation about the arithmetic
mean among this group was 0.036 on the old asphalt surface and 0.027 on
the old concrete surface. The agency believes that the difference
between the traction coefficients of the 196 tires tested on the old
skid pads and the 254 tires tested on the new skid pads may be due to
differences in the old and the new pads or differences in the tire
populations of 1989-1991 and 1992-1994. In any case, all future
traction testing will occur on the new pads since the old pads no
longer exist.
Based on the average traction coefficient and standard deviation
values from the new pads, the agency proposes adding a fourth category,
designated as ``AA,'' to the traction grade only for tires with
traction coefficients that exceed 0.54 (representing the mean, 0.516,
and adding the standard deviation of 0.029) when tested on wet asphalt
and 0.38 (0.364, the mean, +0.017, the standard deviation) when tested
on wet concrete. Of the 254 tires tested as described above, only 8
would currently qualify for the new ``AA'' grade. The agency believes,
however, that an optional new traction rating would provide an
incentive for manufacturers to improve the traction performance of
other tire lines.
NHTSA disagrees with GT and Dunlop that providing a means for
differentiating the highest traction tires would cause confusion among
consumers. To the contrary, NHTSA believes that adding the ``AA''
rating would benefit consumers by providing them additional guidance
for choosing the proper tires to suit their individual needs.
Since upgrading traction performance to take advantage of the
``AA'' rating is optional, tire manufacturers would not necessarily
incur any additional costs. Those manufacturers that chose to use the
AA rating would be free to pass on whatever additional costs they would
incur to their customers (see discussion of costs below).
NHTSA agrees with Goodyear, Michelin and MTS that there is a
correlation between peak and sliding traction and that both values can
be considered equivalent for grading purposes. However, the agency is
persuaded by the comments of Dunlop, Cooper and BF that the majority of
vehicles currently on the road are not equipped with ABS. Thus, they
depend on sliding traction rather than peak traction for maximum
stopping action. Accordingly, NHTSA does not propose to include peak
traction in the traction ratings at this time.
3. Costs and Benefits
The proposed amendments to the traction grade under the UTQGS would
create an additional level of traction rating the use of which would be
optional to manufacturers. Therefore, the proposed ``AA'' traction
rating would apply only to those manufacturers who elect to produce
tires that meet the proposed ``AA'' criteria and label those tires
accordingly. As discussed in IIIB above, only 8 of the 254 tires skid-
tested by NHTSA would qualify for the proposed ``AA'' rating. The
manufacturers' costs of reworking tire molds to accommodate the new
traction rating would be minimal and would be necessary only for this
small group and only if the manufacturers of those tires opted to give
those tires the new, higher grade. The paper labels required by 49 CFR
575.104(d)(1)(i)(B)(2), however, would need to be changed to reflect
the 4-grade rating system.
C. Temperature/Rolling Resistance/Fuel Economy
1. Public Comments
All comments on the Request for Comments addressed the temperature/
rolling resistance/fuel economy issue. Nine trade and consumer
associations responded, including engineering companies and test
laboratories, 5 of which supported a rolling resistance grade and 4 of
which were opposed. Seven tire manufacturers responded, 6 of which
opposed a rolling resistance grade either as a substitute for the
temperature resistance grade or as a fourth rating category under the
UTQGS. Fourteen private citizens commented, 9 of whom supported a
rolling resistance grade, while 5 were opposed.
The members of the public and the private associations and
companies that opposed a rolling resistance grade cited various
objections to it. For example, Mr. Christopher Smith of Pennsylvania
asserted that NHTSA should not be concerned with rolling resistance
because it robs consumers of their choices. Mr. Fred Crum of California
stated that road surface ratings are more important than rolling
resistance ratings if fuel savings are to be achieved. Mr. Robert
Burns, President of the Private Brand Tire Group (PBTG) asserted that
the government should not force consumers to bear the cost of testing
and remolding a new UTQGS symbol which will be passed on to them by
manufacturers. Advocates for Highway Safety (AHS) expressed concern
that addition of a rolling resistance rating could cause consumers, for
reasons of economy, to purchase tires that have a lower overall
traction performance.
Cooper, Dunlop, Goodyear, BF and GT argued that rolling resistance
and temperature resistance are separate properties. They asserted that
rolling resistance measures the energy consumed by the tire, which
relates to the efficiency of the tire in converting motive power to
distance traveled, while temperature resistance relates to the ability
of the tire structure and materials to withstand the temperatures
generated by the flexing of the rubber and its reinforcing materials.
The PBTG opposed the deletion of the temperature resistance grade,
asserting that the temperature resistance characteristics of tires are
relevant to such hot climates as the American desert southwest where
tire dealers choose their tire lines on [[Page 27479]] this basis.
Cooper and Dunlop stated that such desert countries as Saudi Arabia
require tires imported into their countries to be rated at least ``B''
for temperature resistance. Goodyear, on the other hand, supported the
deletion of the temperature resistance rating because, as NHTSA
discussed in the Request for Comments of April 25, 1994, the majority
of consumers pay no attention to this rating when purchasing tires.
Michelin also supported the deletion of the temperature resistance
grade, stating that the voluntary speed ratings placed on some tires by
manufacturers in accordance with SAE Recommended Practice J1561,
Laboratory Speed Test Procedure for Passenger Car Tires, adequately
represent the temperature resistance capability of the tire.
Michelin commented that vehicle manufacturers, in order to meet
fuel economy requirements, have long required their tire suppliers to
provide low rolling resistance original equipment (OE) tires, while
still imposing strict standards on treadwear, traction, and speed
durability. Michelin stated that since 1980 tire rolling resistance has
in some cases been reduced by as much as 50 percent while still
maintaining other performance characteristics. BF asserted that the
rolling resistance of OE tires is constantly being improved to meet
CAFE standards and that that technology is included in after-market
tires through standardization. Therefore, BF argued that there is no
need to establish a rolling resistance grade for the UTQGS.
NTDRA, PBTG, Goodyear, and GT argued that a rolling resistance
grade would be costly and yield little or no consumer benefit because
of lack of consumer interest. NTDRA contended that a rolling resistance
grade would constitute an unnecessary cost burden on manufacturers.
Goodyear, claiming a the lack of success of its Invicta GFE model low
rolling resistance tire, stated that there is little public interest in
low rolling resistance/fuel efficient tires because of their increased
cost. STL asserted that there are too many variables in measuring
rolling resistance to be of any consumer benefit. Goodyear, Michelin,
Dunlop and Cooper stated that even tires of the same size designation,
construction and load-carrying capacity can have different rolling
resistance characteristics. PBTG, Goodyear, GT, BF, and Dunlop argued
that rolling resistance cannot be improved without adversely affecting
treadwear and traction. Michelin disagreed with this assertion, saying
that tire manufacturers have used tire technology to reduce rolling
resistance in OE tires without adversely affecting treadwear or
traction.
Manufacturers generally agreed that there would be a difference in
production and consumer costs between grading for temperature
resistance and rolling resistance, but did not specify what such
difference might be. Goodyear stated that it costs less to test for
rolling resistance than for temperature resistance, but more tests
would probably be required. Goodyear estimated that rolling resistance
tests cost $175 per test while temperature resistance tests cost $250
per test. BF stated that it would be ``extremely expensive'' to
consumers to implement all the changes suggested by NHTSA in the
Request for Comments. GT estimated that to achieve reduced rolling
resistance without loss of the other tire properties would increase
tire costs to consumers by 15 percent, due to the increased cost of
redesigning and testing of tire lines. Goodyear asserted that a tire
designed to minimize rolling resistance may have a shorter tread life,
thereby creating the need for more tires with associated increased
energy consumption. The American Retreaders Association expressed
concern that such low rolling resistance tires may not be retreadable.
PBTG, Goodyear, BF, GT, Dunlop, NTDRA and Cooper asserted that the
best course of action would be for NHTSA to mount a publicity campaign
to educate the public with respect to proper tire maintenance and
encourage people to maintain proper inflation pressure, proper balance
and alignment, and obey speed limits. The commenters asserted that
those measures would have a more significant effect on reduction of
greenhouse gasses than grading tires for their rolling resistance
characteristics. Nevertheless, Dunlop, BF, Goodyear, GT, and Cooper
suggested that if NHTSA decides to proceed with the rolling resistance
grade, the agency should make the requirement effective for newly-
introduced tire lines only.
The lone manufacturer supporting the establishment of a rolling
resistance grade was Michelin. That company supported the deletion of
the temperature resistance grade, stating that it does not serve the
purpose for which it was intended and does not provide useful consumer
information. Michelin asserted, on the other hand, that establishment
of a rolling resistance grade for all tires would encourage
manufacturers to improve the rolling resistance characteristics of
replacement tires and bring them up to the capabilities of OE tires.
Michelin estimated that the additional consumer cost would be less than
$1 per tire, but in any case no more than $2.50 per tire. Michelin
believes that those costs would be more than offset by the value of the
fuel conservation and reduction of global warming gases that rolling
resistance labeling would make possible.
2. Agency Decision
a. Temperature resistance. The temperature resistance grade under
the UTQGS represents a tire's ability to dissipate and withstand heat
buildup that can cause the tire to degenerate and result in a reduction
of tire life or even tire failure. Currently, 20.4 percent of new
replacement tire lines are rated A, 51.8 percent are rated B, and 26.4
percent are rated C.
The temperature resistance grade is not widely understood by
consumers and therefore most do not find it useful when purchasing
tires. NHTSA's data indicate that of consumers purchasing tires for
their own use, 38 percent have heard of the temperature resistance
grade, while only 12 percent consider it in making tire selections. The
comparable figures for the other types of ratings are 74 percent and 29
percent for the treadwear ratings and 65 and 27 percent for the
traction ratings.
As stated above, in order to create wider knowledge and better
understanding of the UTQGS ratings among consumers, including the
temperature resistance rating, NHTSA has issued consumer information
bulletins, press releases, and has required labels to be affixed to
each individual tire. These efforts seemed to arouse little public
interest and had no lasting effect. NHTSA has considered expanding its
publicity efforts into nationwide publicity campaigns, but such
publicity campaigns are very expensive. Further, based on the lack of
response to previous publicity on the subject, NHTSA has no reason to
believe that a widespread, expensive publicity campaign would produce
any more significant results than past efforts. NHTSA believes that the
safety purposes of the temperature resistance grade can be essentially
met by other existing measures. The high speed performance test
specified in section S5.5 of Standard No. 109, New pneumatic tires,
assures the minimum temperature resistance performance for all
passenger car tires. That section requires that tires be tested at 75
miles per hour (mph) for 30 minutes, at 80 mph for 30 minutes, and
again at 85 mph for 30 minutes. At the end of the test, the tire must
have not less than the initial inflation pressure and must not
[[Page 27480]] show the indications of damage specified in paragraph
S4.2.2.5(a) of Standard No. 109. Successful completion of this test
equates to a temperature resistance grade of ``C'' under the UTQGS.
That meets at least the minimum requirements under the UTQGS.
To accommodate those with special needs, such as law enforcement
vehicles that require tires capable of sustained high speeds or those
operating in areas of high ambient temperatures, tire speed ratings are
available. These ratings are voluntary industry ratings in accordance
with the procedures set forth in SAE-J1561. Such ratings are indicated
by symbols molded onto or into tire sidewalls which range from the
``S'' category, meaning capability of sustained speeds up to 112 mph,
to the ``Y'' category, meaning capability of sustained speeds up to 186
mph. Tires above the ``S'' category would be equivalent to a UTQGS
temperature resistance rating of ``A.''
With respect to Michelin's comment, noted above, that the
manufacturers' voluntary speed ratings adequately represent the
temperature resistance capability of a tire, NHTSA has no data about
the number of consumers who know of and consider the industry speed
ratings. The agency believes, however, that consumers who need, for
reasons such as occupation or climate, tires with higher speed ratings
are motivated to obtain information about the industry speed ratings
and consider them in selecting replacement tires.
For those reasons, NHTSA proposes to delete the temperature
resistance rating from the UTQGS, substituting therefor a rolling
resistance/fuel economy rating, as discussed below. NHTSA believes that
since the UTQGS are intended to be meaningful and helpful to the tire-
buying public in selecting tires that suit their individual needs, the
agency should continue its efforts to make the UTQGS as meaningful and
helpful as possible to consumers by rating those tire characteristics
which the public understands and in which the public is interested.
b. Rolling resistance/fuel economy. Based on the public comments in
response to the agency's April 25, 1994 Request for Comments, the
agency believes that there is a direct correlation between rolling
resistance and fuel economy. Michelin commented that a 5 percent
reduction in rolling resistance results in a 1 percent fuel savings at
highway speeds, regardless of the vehicle's fuel consumption. The
agency would welcome comments on the validity of this relationship.
NHTSA also solicits comments on how the relationship would be
affected by various real-world driving conditions, such as temperature,
precipitation, vehicle speed, and road conditions, and vehicle
conditions such as wheel alignment, tire balance, and inflation
pressures. Even if that relationship would not be affected by those
conditions, NHTSA assumes that any such fuel savings would be reduced
in direct proportion to the number of tires on the vehicle that do not
have low rolling resistance. For example, under this assumption, a
vehicle equipped with 2 low rolling resistance tires and 2 tires with
rolling resistance typical of current replacement tires would achieve
only half the savings of the same vehicle equipped with 4 low rolling
resistance tires. The agency requests comment on that assumption.
The agency does not agree with the assertions of some commenters
that rolling resistance cannot be improved without detracting from the
other tire characteristics. NHTSA agrees with commenters on the Request
for Comments that although rolling resistance and temperature
resistance are separate properties, there is a correlation between
rolling resistance and heat generation. Rolling resistance contributes
to heat buildup which can ultimately result in tire failure. Thus, a
tire with lower rolling resistance will normally run cooler, and
therefore safer, than a tire with higher rolling resistance. In
addition, a tire with lower rolling resistance creates less friction,
thus contributing to tire efficiency which in turn results in less fuel
consumption.
Michelin and other commenters pointed out that the rolling
resistance of OEM tires has been significantly reduced in recent years
to assist vehicle manufacturers in meeting corporate auto fuel economy
(CAFE) standards, without loss of traction or treadwear. Since the
achievement of rolling resistance reductions without adverse safety
consequences is a significant issue, NHTSA solicits more specific data
on the differences in rolling resistance and traction characteristics
between OEM and replacement tires at the manufacturers' recommended
pressures and at typical inflation pressures.
While the cheapest way of reducing rolling resistance would also
reduce traction, there are other ways, such as alternative tread
compounds, that are reasonable in cost and that may not affect
traction. Further, the UTQGS traction ratings would inform purchasers
when making a particular tire choice that would involve a reduction in
traction. Therefore, there should logically be no inherent detraction
from treadwear or traction capabilities by the production and purchase
of low rolling resistance replacement tires. Nevertheless, the agency
solicits comments on the extent to which, if at all, there is or could
be a trade-off between safety characteristics such as traction and low
rolling resistance. If such trade-offs do exist-- (1) to what extent
would this occur in real-world driving and vehicle conditions and
typical inflation pressures? (2) how do tire manufacturers trade off
those characteristics between OEM and replacement tires? (3) to what
extent to the trade-offs vary for the different ways of reducing
rolling resistance?
NHTSA has no data regarding Goodyear's assertion that low rolling
resistance tires may have a shorter tread life, thus requiring more
tires with associated increased energy consumption and the adverse
environmental consequences of more scrap tires for disposal. NHTSA has
not received any reports or indication that low rolling resistance OEM
tires tend to have lower treadwear grades. To the contrary, as
discussed above, treadwear grades have steadily increased over the past
several years. Nevertheless, information is requested on any
differences in treadwear ratings between OEM and replacement tires.
Several comments suggested that there was no public interest in
lower rolling resistance. This suggestion appears to be based largely
on speculation. One commenter did rely on the lack of success of its
reduced rolling resistance tire. The agency does not believe that much
reliance can be placed on that experience. When that tire was being
sold, there was no comparative information available to the public
regarding the rolling resistance of other tires.
NHTSA believes that while significant improvements have been made
in the rolling resistance of OEM tires in the last 15 years, changes in
replacement tire rolling resistance have lagged behind somewhat. The
agency has no data, and Michelin provided no specifics, regarding that
company's assertion that the rolling resistance of OEM tires has been
reduced by 50 percent since 1980. Similarly, NHTSA has no data
indicating that, as BF contended, the low rolling resistance technology
of OEM tires is being applied to replacement tires. Although that might
eventually happen, NHTSA believes that there is an equally strong
possibility that it will not. The agency would welcome data on the
amount of [[Page 27481]] reduction in rolling resistance in OEM tires
since 1980 and to what extent, if any, such technology has been applied
to currently available replacement tires.
Tire manufacturers have been producing low rolling resistance OEM
tires for vehicle manufacturers since 1980 and equivalent low rolling
resistance tires are available on the replacement market to some
extent. However, comparative information on the fuel economy benefits
of such tires is not available to consumers. The agency seeks to
expedite the availability of low rolling resistance tires by
encouraging tire manufacturers to produce low rolling resistance
replacement tires and emphasize the economic and environmental
advantages of such tires in their promotional advertising. NHTSA will
also publicize the advantages of low rolling resistance tires and
encourage the public to purchase them.
NHTSA disagrees with commenters that suggested that a public
education program encouraging proper tire maintenance would result in
as much fuel conservation as requiring a rolling resistance grade. The
agency is aware that a great deal of fuel is unnecessarily consumed by
improper tire maintenance, particularly improper inflation pressure.
However, the agency believes that even if the motoring public did
properly maintain all tires, there would continue to be potential fuel
savings available by reducing the rolling resistance of replacement
tires.
ARA did not explain why it thought low rolling resistance tires
would not be retreadable. In response to the ARA comment, however,
Michelin stated that low rolling resistance tires have routinely been
retreaded without any problems. NHTSA has not received any information
or complaints on this issue, which could indicate that there is no
significant problem with retreading low rolling resistance tires. The
agency also notes that it is not aware that many car tires are
currently retreaded. NHTSA would welcome comments on this issue,
however, particularly if there are problems with retreadability,
including the types and sizes of tires involved.
Some commenters stated that the rolling resistance of larger tires
is less than that of smaller tires under the same loading conditions.
For instance, Cooper commented that tire size makes a difference in
rolling resistance measurements because tire loading is not precisely
proportional to tire size. Michelin reported rolling resistance values
of 8.3 kilograms per ton to 9.8 kilograms per ton for tires in a given
tire line having the same rim diameter and aspect ratio, but of
different width.
NHTSA does not believe that the variation in the rolling resistance
of different sized tires would be so great as that reported by Michelin
under the procedures of SAE J-1269. The agency believes that, as
measured under test loading conditions, rolling resistance should
remain approximately the same for all tire sizes in a tire line. If
certain tire lines do show substantial differences in rolling
resistance among sizes, testing of each size may be necessary to
determine fuel economy grades. Depending on the number of tires and
lines involved, manufacturers might choose to grade each size
individually or assign the lower value to all tires within the same
line. At the extreme, there may be two or three rolling resistance
values for a tire line, just as there is presently for temperature
resistance or treadwear.
For the reasons discussed above, the agency proposes to delete the
temperature resistance grade from the UTQGS and substitute a fuel
economy grade. The agency considers fuel economy more understandable
and more meaningful to the tire-buying public than the temperature
resistance rating. As pointed out above, the latter is not widely
understood or utilized by the public in their tire purchases. Finally,
addition of the fuel economy grade furthers the initiatives in the
Climate Change Action Plan issued by the Administration in a national
effort to reduce greenhouse gas emissions.
The agency is proposing to base the new fuel economy rating on a
rolling resistance coefficient instead of rolling resistance itself
since this will partially normalize rolling resistance variations by
tire size within a tire line. The rolling resistance coefficient
(Cr) is calculated by dividing the rolling resistance by the load
on the tire when tested in accordance with SAE J-1269. Michelin stated
that this coefficient ranges from 0.0073 to 0.0156, while Goodyear
assessed the range as being between 0.0067 and 0.0152, and STL fixed it
at 0.005 to 0.015.
Using 0.010 as the midpoint of the range, one method of rating fuel
economy based on the rolling resistance coefficient would be by rating
tires with a coefficient of less than 0.010 as ``A'' for fuel economy.
Tires with a coefficient of 0.010 to 0.015 could be graded ``B'', while
tires with a rolling resistance coefficient greater than 0.015 could be
rated ``C''. This approach would be consistent with the views of those
commenters who stated that if a rolling resistance/fuel economy rating
were established, the A, B, and C ratings would be simpler, and
therefore preferable.
Michelin, on the other hand, prefers a more differentiated,
quantitative expression of the amount of potential fuel savings than
would be provided by a general indication as in the case of the letter
ratings. The agency believes that some consumers might also prefer this
method. For example, a rolling resistance coefficient of 0.0080 would
be graded as a 9 percent increase in fuel savings (100(0.0150-0.0080)/
(0.0150)(5)) compared to a rolling resistance coefficient of 0.0150
(the number (5) in the preceding calculation represents a 5 percent
change in rolling resistance, corresponding to a 1 percent change in
fuel economy). A rolling resistance coefficient of 0.0150 or greater
would be graded as 0 percent, indicating no fuel savings.
The agency seeks to make the rolling resistance/fuel economy rating
as meaningful as possible to consumers. Accordingly, the agency
solicits comments on the feasibility and preferability of the two
methods of expressing the rating as discussed above, namely the A, B,
and C method or the method quantifying the amount of potential fuel
savings of the tire.
Note: All amendments related to the former method are identified
in the regulatory text as ``alternative 1'' and all those related to
the latter method are identified as ``alternative 2.''
3. Costs and Benefits.
The requirement to test and label all tires for rolling resistance
could add to the testing costs associated with the production of tires.
NHTSA believes that some of the costs of grading tires for rolling
resistance would be offset by the deletion of testing for temperature
resistance. Some commenters stated that although the rolling resistance
test is less costly than the temperature resistance test, tire
manufacturers may need to conduct more rolling resistance tests on
different tire sizes to determine accurate fuel economy grades.
GT estimated the cost of rolling resistance testing at $250 per
test, while Goodyear estimated $175 and BF estimated $100. Considering
those comments, NHTSA believes that, as stated in the Request for
Comments of April 25, 1994, the cost of a rolling resistance test
should not exceed $250. The commenters variously estimated the cost of
rolling resistance testing machines at between $400,000 and $1.2
million. Cooper stated that if rolling resistance tests were required,
it would require a capital investment of $1.2 million to purchase 4
test machines. Considering the data submitted by commenters, NHTSA
estimates that a single tire station rolling resistance test
[[Page 27482]] machine can be purchased for $500,000. NHTSA also notes,
however, that tire manufacturers have the option of contracting with
independent testing laboratories for their testing requirements,
thereby avoiding a large capital outlay.
NHTSA estimates that the costs of labeling for fuel economy would
be minimal, probably no more than pennies per tire. That conclusion is
based on Cooper's statement that its total UTQGS labeling costs are
$0.10 per tire, and Michelin's statement that its total UTQGS labeling
could cost up to $0.15 per tire. On this issue, NHTSA agrees with
Michelin that if given sufficient lead time to change tire molds during
a regular replacement cycle, the proposed labeling changes would have
negligible cost impact.
NHTSA estimates that the consumer cost of improving rolling
resistance would be no more than $5 per tire, or $20 per set of 4.
However, those figures are based on the projected cost of reducing the
average rolling resistance of OEM tires by 10 percent, not on the cost
of reducing average aftermarket tires' rolling resistance values to the
level of average OEM tires. NHTSA solicits additional and more specific
comments on the cost per tire of decreasing the rolling resistance of
typical replacement tires to that of typical OEM tires, including the
magnitude of that reduction in rolling resistance (Michelin asserted
that the average rolling resistance of OEM tires is 22.6 percent lower
than that of average replacement tires) and a description of the
specific materials and design changes on which the cost estimate(s) is
based. Further, are any alternative materials or designs that would
significantly lower costs? To what extent are the answers to this
question affected by typical tire and vehicle maintenance habits by
consumers, such as inflation pressure, wheel alignment and tire
balance?
NHTSA estimates that, assuming the realization of fuel economy
gains of 4 percent, the use of 4 low rolling resistance replacement
tires on a typical passenger car could result in fuel savings of 67
gallons over an assumed 40,000 mile tread life. The present value of
such fuel savings, excluding Federal and state taxes, would be
approximately $58. The average cost-benefit ratio of fuel savings per
tire purchase would therefore be 2.9 to 1 ($58/$20) for passenger cars.
Given these assumptions, the improved rolling resistance of the tires
could in most cases pay for itself in slightly more than 1 year.
However, NHTSA notes that the imposition of rolling resistance
grading would not include any obligation for tire manufacturers to
reduce the rolling resistance of their tires. In fact, if the
manufacturers believe that there is no consumer interest in low rolling
resistance tires, they need not make any changes in their tires other
than adding the grade marking on the sidewall.
D. Lead Time
The agency is proposing to make these amendments effective one year
after issuance of the final rule. The agency believes that this would
be sufficient for the following reasons. None of the amendments would
require tire manufacturers to redesign their tires. Further, neither
the treadwear nor the traction amendments would require the retesting
of any tires. The rolling resistance/fuel economy amendments would
require the testing of all existing tires. However, the agency believes
that that testing could be readily completed in time to begin labeling
tires with rolling resistance information at the end of a year.
Several tire manufacturers urged that the rolling resistance
requirement be made effective for newly introduced tire lines only. The
agency lacks authority to establish effective dates in the requested
fashion. It could phase-in the requirement by percentage of production,
as it has various vehicle standards, or by type of tire. However, NHTSA
believes that a year should be sufficient lead time and that a phase-in
would not be necessary. Nevertheless, the agency requests comment on
these lead time issues.
IV. Rulemaking Analyses and Notices
A. E.O. 12866 and DOT Regulatory Policies and Procedures
This notice has not been reviewed under E.O. 12866, Regulatory
Planning and Review. The agency has considered the impact of this
rulemaking action and has concluded that it is not ``significant''
under the DOT's Regulatory Policies and Procedures. The amendments
proposed in this notice are intended to make the UTQGS more meaningful
and helpful to consumers in selecting tires to meet their needs. The
amendments to the provisions regarding the treadwear and traction
ratings are intended to reduce the treadwear rating inflation
experienced in the past, and to add a traction grade category that
differentiates the highest traction tires from lower traction tires.
Neither of those testing and labeling amendments inherently involves
any additional costs either to manufacturers or to consumers. The
testing costs for a fuel economy grade would be offset by the savings
realized by not having to conduct temperature resistance testing. The
rolling resistance test is cheaper than the temperature resistance
test, but more tire sizes may need to be tested. Additional discussion
of these issues is contained in the agency's Preliminary Regulatory
Evaluation, a copy of which has been placed in the public docket with
this rulemaking action.
B. Regulatory Flexibility Act
NHTSA has considered the impacts of this rulemaking action under
the Regulatory Flexibility Act. I hereby certify that the proposed
amendments would not have a significant economic impact on a
substantial number of small entities. Accordingly, the agency has not
prepared a preliminary regulatory flexibility analysis.
The agency believes that no passenger car tire manufacturers
qualify as small businesses. Small businesses, small organizations, and
small governmental units would be affected by this rulemaking only to
the extent that initially they may voluntarily pay as much as $5 more
per tire for low rolling resistance tires in order to obtain the fuel
savings associated with such tires.
C. National Environmental Policy Act
NHTSA has analyzed this rulemaking for purposes of the National
Environmental Policy Act and has determined that implementation of this
action would have no significant impact on the quality of the human
environment.
Rolling resistance labeling could indirectly result in some modest
environmental benefit, to the extent that such labeling encourages
consumers to buy more fuel efficient aftermarket tires. However, the
agency currently is unable to estimate the extent of any increase in
sales of such tires. For illustrative purposes, the agency estimated
the impacts that would result from 5, 10, and 15 percentage point
increases in the sales of tires with low rolling resistance (NHTSA
believes that the current market share for low rolling resistance tires
in the aftermarket is about 15 percent). Such sales increases could
reduce fleet fuel consumption by 155, 309, and 464 million gallons,
respectively, over the assumed 40,000 mile tread lives of tires. This
range of reductions is equivalent to oil savings of 10 to 30 thousand
barrels per day. Further, such reductions in fuel consumption would
result in vehicle carbon dioxide emission reductions of approximately
1.4, 2.7, and 4.1 million [[Page 27483]] metric tons over the tread
lives of the tires.
D. Federalism
NHTSA has analyzed this proposal in accordance with the principles
and criteria contained in E.O. 12612 and has determined that the
proposals in this notice do not have sufficient federalism implications
to warrant preparation of a Federalism Assessment. No state laws would
be affected.
E. Civil Justice Reform
The proposed amendments in this notice 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 state's
standard is identical to the Federal standard. However, the United
States government, a state or political 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. 49 U.S.C. 30161 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.
V. Comments
A. Comment Closing Date
NHTSA has determined that it is in the public interest to provide a
comment period of less than 60 days in this instance because of the
importance of the President's Climate Change Action Plan to fuel
conservation and the reduction of greenhouse gas emissions into the
environment. In addition, the Joint Conference Report on the Department
of Transportation's Fiscal Year 1995 Appropriations directed the agency
to issue a rolling resistance tire labeling rule by June 1, 1995.
B. General
Interested persons are invited to submit comments on the amendments
proposed in this rulemaking action. It is requested but not required
that any comments be submitted in 10 copies each.
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 shown above, and 7
copies from which the purportedly confidential information has been
expunged should be submitted to the Docket Section. A request for
confidentiality should be accompanied by a cover letter setting forth
the information specified in 49 CFR part 512, the agency's confidential
business information regulation.
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 too late for consideration in
regard to the final rule will be considered as suggestions for further
rulemaking action. Comments on the proposal will be available for
public inspection in the docket. NHTSA will continue file relevant
information in the docket after the 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 rules 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 protection, Motor vehicle safety, Reporting and
recordkeeping, 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 continues to read as
follows:
Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166;
delegation of authority at 49 CFR 1.50.
2. Section 575.104 would be amended by revising paragraphs (a);
(d)(1)(i)(B); (d)(1)(ii); (d)(1)(iii); (d)(2)(i), and (d)(2)(ii)
introductory text; adding paragraph (d)(2)(ii)(D); revising paragraphs
(d)(2)(iii); (e)(2)(ix)(C); and (g); Table 1; and Figure 1; and in
Figure 2, by revising Part I and in Part II, by removing the paragraph
for ``Temperature'' and adding a paragraph for ``Fuel Economy''; and by
removing Table 2A and sections (i) through (l).
Sec. 575.104 Uniform tire quality grading standards.
(a) Scope. This section requires motor vehicle and tire
manufacturers and tire brand name owners to provide information
indicating the relative performance of passenger car tires in the areas
of treadwear, traction, and fuel economy.
* * * * *
(d) Requirements--(1) Information. * * *
Alternative 1 to paragraph (d)(1)(i)(B)
(i)(B) Each tire manufactured on and after the effective date of
these amendments, other than a tire sold as original equipment on a new
vehicle, shall have affixed to its tread surface so as not to be easily
removable a label or labels containing its grades and other information
in the form illustrated in Figure 2, Parts I and II. The treadwear
grade attributed to the tire shall be either imprinted or indelibly
stamped on the label containing the material in Part I of Figure 2,
directly to the right of or below the word ``TREADWEAR''. The traction
grade attributed to the tire shall be indelibly circled in an array of
the potential grade letters AA, A, B, or C, directly to the right of or
below the words ``TRACTION'' in Part I of Figure 2. The fuel economy
grade attributed to the tire shall be indelibly circled in an array of
the potential grade letters A, B, or C directly to the right of or
below the words ``FUEL ECONOMY'' in Part I of Figure 2. The words
``TREADWEAR'', ``TRACTION'', and ``FUEL ECONOMY,'' in that order, may
be laid out vertically or horizontally. The text of Part II of Figure 2
may be printed in capital letters. The text of Part I and the text of
Part II of Figure 2 need not appear on the same label, but the edges of
the two texts must be positioned on the tire tread so as to be
separated by a distance of no more than one inch. If the text of Part I
and the text of Part II of Figure 2 are placed on separate labels, the
notation ``See EXPLANATION OF DOT QUALITY GRADES'' shall be added to
the bottom of the Part I text, and the words ``EXPLANATION OF DOT
QUALITY GRADES'' shall appear at the top of the Part II text. The text
of Figure 2 shall be oriented on the tire tread surface with lines of
type running perpendicular to the tread circumference. If a label
bearing a tire size designation is attached to the tire tread surface
and the tire size designation is oriented with lines of type running
perpendicular to the tread [[Page 27484]] circumference, the text of
Figure 2 shall read in the same direction as the tire size designation.
ALTERNATIVE 2 TO PARAGRAPH (d)(1)(i)(B)
(i)(B) Each tire manufactured on and after the effective date of
these amendments, other than a tire sold as original equipment on a new
vehicle, shall have affixed to its tread surface so as not to be easily
removable, a label or labels containing its grades and other
information in the form illustrated in Figure 2, Parts I and II. The
treadwear grade attributed to the tire shall be either imprinted or
indelibly stamped on the label containing the material in Part I of
Figure 2, directly to the right of or below the word ``TREADWEAR.'' The
traction grade attributed to the tire shall be indelibly circled in an
array of the potential grade letters AA, A, B, or C, directly to the
right of or below the word ``TRACTION.'' The fuel economy grade
attributed to the tire shall be either imprinted or indelibly stamped
on the label containing the material in Part I of Figure 2, directly to
the right of or below the words ``FUEL ECONOMY.'' The words
``TREADWEAR,'' ``TREADWEAR,'' and ``FUEL ECONOMY,'' in that order, may
be laid out vertically or horizontally. The text of Part II of Figure 2
may be printed in capital letters. The text of Part II of Figure 2 may
be printed in capital letters. The text of Part I and the text of Part
II of Figure 2 need not appear on the same label, but the edges of the
two texts must be positioned on the tire tread so as to be separated by
a distance of no more than one inch. If the text of Part I and the text
of Part II of Figure 2 are placed on separate labels, the notation
``See EXPLANATION OF DOT QUALITY GRADES'' shall be added to the bottom
of the Part I text, and the words ``EXPLANATION OF DOT QUALITY GRADES''
shall appear at the top of the Part II text. The text of Figure 2 shall
be oriented on the tire tread surface with lines of type running
perpendicular to the tread circumference. If a label bearing a tire
size designation is attached to the tire tread surface and the tire
size designation is oriented with lines of type running perpendicular
to the tread circumference, the text of Figure 2 shall read in the same
direction as the tire size designation.
ALTERNATIVE 1 TO PARAGRAPH (d)(1)(ii)
(ii) In the case of information required in accordance with
Sec. 575.6(c) to be furnished to prospective purchasers of motor
vehicles and tires, each vehicle manufacturer and each tire
manufacturer or brand name owner shall, as part of that information,
list all possible grades for traction and fuel economy, and restate
verbatim the explanations for each performance area specified in Figure
2. The information need not be in the same format as in Figure 2. In
the case of a tire manufacturer or brand name owner, the information
must indicate clearly and unambiguously the grade in each performance
area for each tire of that manufacturer or brand name owner offered for
sale at the particular location.
ALTERNATIVE 2 TO PARAGRAPH (d)(1)(ii)
(ii) In the case of information required in accordance with
Sec. 575.6(c) to be furnished to prospective purchasers of motor
vehicles and tires, each vehicle manufacturer and each tire
manufacturer or brand name owner shall, as part of that information,
list all possible traction grades and restate verbatim the explanations
for each performance area specified in Figure 2. The information need
not be in the same format as in Figure 2. In the case of a tire
manufacturer or brand name owner, the information must indicate clearly
and unambiguously the grade in each performance area for each tire of
that manufacturer or brand name owner offered for sale at the
particular location.
ALTERNATIVE 1 TO PARAGRAPH (d)(1)(iii)
(iii) In the case of information required in accordance with
Sec. 575.6(a) to be furnished to the first purchaser of a new motor
vehicle, other than a motor vehicle equipped with tires manufactured
prior to the effective date of these amendments, each manufacturer of
motor vehicles shall, as part of the information, list all possible
grades for traction and fuel economy, and restate verbatim the
explanation for each performance area specified in Figure 2. The
information need not be in the format of Figure 2, but it must contain
a statement referring the reader to the tire sidewall for the specific
tire grades for the tires with which the vehicle is equipped.
ALTERNATIVE 1 TO PARAGRAPH (d)(1)(iii)
(iii) In the case of information required in accordance with
Sec. 575.6(a) to be furnished to the first purchaser of a new motor
vehicle, other than a motor vehicle equipped with tires manufactured
prior to the effective date of these amendments, each manufacturer of
motor vehicles shall, as part of the information, list all possible
grades for traction and fuel economy, and restate verbatim the
explanation for each performance area specified in Figure 2. The
information need not be in the format of Figure 2, but it must contain
a statement referring the reader to the tire sidewall for the specific
tire grades for the tires with which the vehicle is equipped.
(2) Performance--(i) Treadwear. Each tire shall be graded for
treadwear performance with the word ``TREADWEAR'' followed by a number
of two or three digits representing the tire's grade for treadwear,
expressed as a percentage of the NHTSA nominal treadwear value, when
tested in accordance with the conditions and procedures specified in
paragraph (e) of this section. Treadwear grades shall be in multiples
of 20 (for example, 80, 120, and 160).
(ii) Traction. Each tire shall be graded for traction performance
with the word ``TRACTION,'' followed by the symbols C, B, A, or AA,
when the tire is tested in accordance with the conditions and
procedures specified in paragraph (f) of this section.
* * * * *
(D) The tire may be graded AA only when its adjusted traction
coefficient is both:
(1) More than 0.54 when tested in accordance with paragraph (f)(2)
of this section on the asphalt surface specified in paragraph (f)(1)(i)
of this section; and
(2) More than 0.38 when tested in accordance with paragraph (f)(2)
of this section on the concrete surface specified in paragraph
(f)(1)(i) of this section.
ALTERNATIVE 1 TO PARAGRAPH (d)(2)(iii)
(iii) Fuel economy. Each tire shall be graded for fuel economy
performance with the words ``FUEL ECONOMY'' followed by the letter A,
B, or C, based on its performance when the tire is tested in accordance
with the procedures specified in paragraph (g) of this section.
(A) The tire may be graded A only if its rolling resistance
coefficient is less than 0.010.
(B) The tire may be graded B only if its rolling resistance
coefficient is equal to or greater than 0.010 but less than 0.015.
(C) The tire may be graded C if its rolling resistance coefficient
equal to or greater than 0.015.
ALTERNATIVE 2 TO PARAGRAPH (d)(2)(iii)
(iii) Fuel economy. Each tire shall be graded for fuel economy
performance [[Page 27485]] with the words ``FUEL ECONOMY'' followed by
the tire's rated percentage of increase in fuel savings, such as
``5%'', based on the tire's performance when tested in accordance with
the procedures specified in paragraph (g) of this section.
* * * * *
(e) Treadwear grading conditions and procedures. * * *
(2) Treadwear grading procedure. * * *
(ix) * * *
(C) Determine the course severity adjustment factor by assigning a
base wear rate of 1.47 to the course monitoring tires and dividing that
rate by the average wear rate for the four course monitoring tires.
* * * * *
ALTERNATIVE 1 TO PARAGRAPH (g)
(g) Fuel economy grading. The fuel economy grade is calculated as
follows:
(1) The tire's rolling resistance coefficient is determined in
accordance with the procedures of SAE Recommended Practice J-1269,
Rolling Resistance Measurement Procedure for Passenger Car, Light
Truck, and Highway Truck and Bus Tires, revised March, 1987 (SAE J-
1269).
(2) The rolling resistance coefficient (Cr) is the ratio of
rolling resistance force (Fr) to the normal load on the tire:
(Fn) or Cr=Fr Fn.
Example No 1. Fn=1,100 pounds of force (lbf); Fr=8 lbf;
then Cr=8 1,00=0.00727.
A rolling resistance coefficient of 0.00727 would result in a
grade of ``A'' for fuel economy.
Example No. 2. Fn=1,100 lbf, and Fr=18 lbf, then
Cr=18 1,100=0.01636.
A rolling resistance coefficient of 0.01636 would result in a
grade of ``C'' for fuel economy.
ALTERNATIVE 2 TO PARAGRAPH (g)
(g) Fuel economy grading. The fuel economy grade is calculated as
follows:
(1) The tire's rolling resistance coefficient is determined in
accordance with the procedures of SAE Recommended Practice J-1269,
Rolling Resistance Measurement Procedure for Passenger Car, Light
Truck, and Highway Truck and Bus Tires, revised March, 1987 (SAE J-
1269).
(2) The rolling resistance coefficient (Cr) is the ratio of rolling
resistance force (Fr) to the normal load on the tire: (Fn) or
Cr=FrFn.
Example No 1. Fn=1,100 pounds of force (lbf); Fr=8 lbf; then
Cr=8=1,100=0.00727.
Example No. 2. Fn=1,100 lbf, and Fr=18 lbf, then
Cr=181,100=0.01636.
(3) Determine the tire's fuel economy grade by subtracting its
rolling resistance coefficient from 0.0150, then multiply by 1,333. The
resulting number, rounded to the nearest whole number, is the fuel
economy grade, expressed as a percentage.
(i)(A) Using the numbers in Example No. 1 in paragraph (g)(2) of
this section, given the rolling resistance coefficient (Cr) of 0.00727,
the fuel economy grade (Fg) would be calculated as follows:
Fg=(0.0150-0.00727) x 1,333=(0.00773) x 1,333=10.30 percent, rounded
to 10 percent.
(B) This would represent an increase of 10 percent in fuel economy,
expressed as a fuel economy grade of ``10%''.
(ii) Using the numbers in Example No. 2 in paragraph (g)(2) of
this section: If Fn=1,100 lbf, and Fr=18 lbf, then
Cr=181,100=0.01636
Fg=(0.0150-0.01636) x 1,333=(-0.00136) x 1,333 =-1.82 or 0 percent
A negative value represents a 0 percent increase in fuel economy,
and would be expressed as a fuel economy grade of ``0%''.
Table 1.--Test Inflation Pressures
(11)Max
imum
permis
sible
inflat
ion
pressu
re for
the
treadw
ear
test
----------------------------------------------------------------------------------------------------------------
(7)Tire
s
other
than
CT
tires
(3)CT
Tires
----------------------------------------------------------------------------------------------------------------
(2)Psi
(4)kPa
(3)kPa
----------------------------------------------------------------------------------------------------------------
32... 36 40 60 240 280 300 340 350 290 330 350 390
24... 28 32 52 180 220 180 220 230 230 270 230 270
* * * * *
ALTERNATIVE 1 TO FIGURE 1
BILLING CODE 4910-59-P
[[Page 27486]]
[GRAPHIC][TIFF OMITTED]TP24MY95.000
[[Page 27487]]
ALTERNATIVE 2 TO FIGURE 1:
[GRAPHIC][TIFF OMITTED]TP24MY95.001
BILLING CODE 4910-59-P
[[Page 27488]] ALTERNATIVE 1 TO FIGURE 2--[PART I]
Figure 2--[Part I]--DOT Quality Grades
TREADWEAR
TRACTION AA A B C
FUEL ECONOMY A B C
ALTERNATIVE 2 TO FIGURE 2--[PART I]
TREADWEAR
TRACTION AA A B C
FUEL ECONOMY
ALTERNATIVE 1 TO FIGURE 2--[PART II]
[Part II] * * *
* * * * *
FUEL ECONOMY
The fuel economy grade gives a relative value of the tire's
potential to affect a motor vehicle's fuel economy. For example, a
vehicle with four tires rated ``A'' for fuel economy would have
lower rolling resistance and therefore greater fuel efficiency than
a vehicle with four tires rated ``B'' or ``C''. Saving fuel reduces
carbon dioxide emissions which contribute to global warming. It
should be noted, however, that actual fuel savings depend on driving
habits, proper vehicle and tire maintenance, proper tire inflation
pressure, road conditions, and climate. The fuel economy grade is
based on testing the tire for rolling resistance under controlled
conditions using specified test procedures. Only tires of the size
appropriate for your car should be compared.
[ALTERNATIVE 2 TO FIGURE 2--[PART II]
[Part II * * *]
* * * * *
FUEL ECONOMY
The fuel economy grade gives a relative value of the tire's
potential to affect a motor vehicle's fuel economy. For example, a
vehicle with four tires rated ``2%'' for fuel economy would achieve
2% higher fuel economy than a vehicle with four tires rated ``0%.''
A vehicle with two tires rated ``2%'' and two tires rated ``0%''
would achieve 1% higher fuel economy than a vehicle with four tires
rated ``0%.'' Saving fuel reduces carbon dioxide emissions which
contribute to global warming. It should be noted, however, that
actual fuel savings depend on driving habits, proper vehicle and
tire maintenance, proper tire inflation pressure, road conditions,
and climate. The fuel economy grade is based on testing the tire for
rolling resistance under controlled conditions using specified test
procedures. Only tires of the size appropriate for your car should
be compared.
* * * * *
Issued on May 17, 1995.
Barry Felrice,
Associate Administrator for Safety Performance Standards.
[FR Doc. 95-12513 Filed 5-18-95; 1:52 pm]
BILLING CODE 4910-59-P
