Honda Acura TSX Sport Wagon 2011 Owner's Manual page 265

Traction
The traction grades, from highest to lowest, are AA, A, B, and C.
Those grades represent the tire's ability to stop on wet pavement as
measured under controlled conditions on specified government test
surfaces of asphalt and concrete. A tire marked C may have poor traction
performance.
Temperature
The temperature grades are A (the highest), B, and C, representing the
tire's resistance to the generation of heat and its ability to dissipate heat
when tested under controlled conditions on a specified indoor laboratory
test wheel. Sustained high temperature can cause the material of the tire
to degenerate and reduce tire life, and excessive temperature can lead to
sudden tire failure. The grade C corresponds to a level of performance
which all passenger car tires must meet under the Federal Motor Vehicle
Safety Standard No. 109. Grades B and A represent higher levels of
performance on the laboratory test wheel than the minimum required by
law.
Checking and Maintaining Tires
Traction
Warning: The traction grade assigned to
this tire is based on straight-ahead braking
traction tests, and does not include
acceleration, cornering, hydroplaning, or
peak traction characteristics.
Temperature
Warning: The temperature grade for
this tire is established for a tire that is
properly inflated and not overloaded.
Excessive speed, underinflation, or
excessive loading, either separately or in
combination, can cause heat buildup and
possible tire failure.
DOT Tire Quality Grading
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