Toyota Prius 2011, Owner'S Manual, Page: 607 / 651

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6-1. Specifications
PRIUS_U (OM47685U) DVD
Uniform Tire Quality Grading
This information has been prepared in accordance with regulations
issued by the National Highway Traffic Safety Administration of the
U.S. Department of Transportation.
It provides the purchasers and/or prospective purchasers of Toyota
vehicles with information on uniform tire quality grading.
Your Toyota dealer will help answer any questions you may have as
you read this information.
n
DOT quality grades
All passenger vehicle tires must conform to Federal Safety
Requirements in addition to these grades. 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
n Treadwear
The treadwear grade is a comparative rating based on the wear
rate of the tire when tested under controlled conditions on a speci-
fied government test course.
For example, a tire graded 150 would wear one and a 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.