TECH CENTER - TIRE TRACTION
A tire's traction grade indicates how well a tire can stop on a wet paved surface without skidding off to a side. There are four possible traction grades: AA, A, B, and C. A rating of AA is the highest possible traction grade, while C is the lowest.
Traction grades are determined by driving a vehicle on wet pavement "skid pads" provided by the U.S. government. At 40mph the wheels are locked, thus placing the entire stopping burden on the tire.
A tire's traction rating only applies to stopping in the test described above. It does not indicate a tire's stability during cornering or at high speeds.
The Uniform Tire Quality Grading System, or UTQGS, requires tire manufacturers to disclose treadwear, traction, and temperature information for tires they produce. This is designed to help customers decide which tires are most suitable to their needs.