The National Highway Traffic Safety Administration (NHTSA) established the Uniform Tire Quality Grading Statdards (UTQGS) in 49 CFR 575.104. The UTQG rating is made up of 3 components:
Treadwear
The treadwear guide is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test track.
A tire graded 200 would wear twice as long on the government test course under specified test conditions as one graded 100. It is wrong to link treadwear grades with your projected tire
mileage. The relative performance of tires depends upon the actual conditions of their use and may vary due to driving habits, service practices, differences in road characteristics and
climate.
Traction
Traction grades, from highest to lowest, are AA, A, B, and C. They represent the tire's ability to stop on wet pavement as measured
under controlled conditions on specified government test surfaces of asphalt and concrete.
Temperature
The temperature grades, from highest to lowest, are A, B and C. These represent the tire's resistance to the generation of heat.