The tires on your vehicle meet all
U.S. Federal Safety Requirements.
All tires are also graded for
treadwear, traction, and temperature
performance according to
Department of Transportation (DOT)
standards. The following explains
these gradings.
Uniform Tire Quality Grading
Quality grades can be found where
applicable on the tire sidewall
between tread shoulder and
maximum section width. For
example:Treadwear 200
Traction AA
Temperature A
All passenger car tires must conform
to Federal Safety Requirements in
addition to these grades. Treadwear
The treadwear grade is a
comparative rating based on the wear
rate of the tire when tested under
controlled conditions on a specified
government test course. For
example, a tire graded 150 would
wear one and one-half (1 1/2) times
as well on the government course as
a tire graded 100. The relative
performance of tires depends upon
the actual conditions of their use,
however, and may depart
significantly from the norm due to
variations in driving habits, service
practices and differences in road
characteristics and climate.
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.
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.
DOT Tire Quality Grading (U.S. Vehicles)
253
Technical Information
10/08/06 08:34:41 11 ELEMENT MMC North America Owner's Man 50 31SCV680 enu
The burning of gasoline in your
vehicle's engine produces several by-
products. Some of these are carbon
monoxide (CO), oxides of nitrogen
(NOx), and hydrocarbons (HC).
Gasoline evaporating from the tank
also produces hydrocarbons.
Controlling the production of NOx,
CO, and HC is important to the
environment. Under certain
conditions of sunlight and climate,
NOx and HC react to form
photochemical‘‘smog. ’’Carbon
monoxide does not contribute to
smog creation, but it is a poisonous
gas. The Clean Air Act
The United States Clean Air Act sets
standards for automobile emissions. It
also requires that automobile
manufacturers explain to owners how
their emissions controls work and
what to do to maintain them. This
section summarizes how the
emissions controls work.Crankcase Emissions Control
SystemYour vehicle has a positive crankcase
ventilation system. This keeps gasses
that build up in the engine's crankcase
from going into the atmosphere. The
positive crankcase ventilation valve
routes them from the crankcase back
to the intake manifold. They are then
drawn into the engine and burned.
Evaporative Emissions Control
System
As gasoline evaporates in the fuel
tank, an evaporative emissions
control canister filled with charcoal
adsorbs the vapor. It is stored in this
canister while the engine is off. After
the engine is started and warmed up,
the vapor is drawn into the engine
and burned during driving.
Onboard Refueling Vapor
Recovery
The onboard refueling vapor
recovery (ORVR) system captures
the fuel vapors during refueling. The
vapors are adsorbed in a canister
filled with activated carbon. While
driving, the fuel vapors are drawn
into the engine and burned off.
Emissions Controls25810/08/06 08:34:41 11 ELEMENT MMC North America Owner's Man 50 31SCV680 enu
