UTQG basics · guide
Tire traction and temperature grades explained
Traction: AA, A, B, C
NHTSA: traction grades indicate “a tire’s ability to stop on wet pavement,” from AA (highest) to C (NHTSA). TIA describes it as stopping “in a straight line on wet pavement” (TIA). The test (49 CFR 575.104(f)) uses wetted asphalt and concrete skid pads and a locked-wheel test trailer, and the grade depends on the adjusted traction coefficient on both surfaces (U.S. Code of Federal Regulations (eCFR)):
| Grade | Asphalt coefficient | Concrete coefficient |
|---|---|---|
| AA | more than 0.54 | more than 0.38 |
| A | more than 0.47 | more than 0.35 |
| B | more than 0.38 | more than 0.26 |
| C | 0.38 or less | 0.26 or less |
To earn a grade the tire must meet both thresholds; C results from either at or below its limit. Source: 49 CFR 575.104(d)(2)(ii).
Not covered: the procedure is a wet, locked-wheel, straight-line stop, so the grade doesn’t test cornering, hydroplaning resistance, dry grip, or snow and ice. For winter performance see all-season vs. all-weather vs. winter.
Temperature: A, B, C
The temperature grade shows resistance to heat build-up (NHTSA). In the test the tire runs against a 67.23-inch steel wheel at 95 °F ambient, loaded to 88% of its maximum load rating, stepping up speed in 30-minute stages (575.104(g)):
| Grade | Rule | Roughly equal to* |
|---|---|---|
| A | Completes the 575 rpm stage with no tread, sidewall, ply or bead separation, chunking or cracking, and pressure held | 115 mph |
| B | Completes the 500 rpm stage but not the 575 rpm stage | 100 mph |
| C | Fails the 500 rpm stage | below that |
*Our arithmetic from the wheel diameter in the regulation (rpm × π × 67.23 in); the regulation specifies rpm, not mph.
In real use USTMA warns that “under inflated tires generate excessive heat build-up and stress, causing irregular wear and internal damage” (USTMA), so keeping correct pressure matters more than the letter. See making tires last longer.
How the grades are distributed
NHTSA gives the split for “current tires”; we also computed it across all 7,628 records in the NHTSA file (which includes older lines; not market share).
| Grade | NHTSA “current tires” | All records in file |
|---|---|---|
| Traction AA | 15% | 17.5% |
| Traction A | 77% | 73.5% |
| Traction B | 7% | 8.9% |
| Traction C | only 4 lines | 5 records |
| Temperature A | 62% | 68.9% |
| Temperature B | 34% | 28.5% |
| Temperature C | 4% | 2.6% |
Most tires land at A or AA for traction, so the letter separates tires less than the treadwear number does. Compare grades within a size on pages such as 225/65R17 and 235/55R19, or by treadwear band: 400–499, 500–599, 600–699, 700–799.
FAQ
What does traction AA mean on a tire?
AA is the highest UTQG traction grade: more than 0.54 on the asphalt skid pad and more than 0.38 on the concrete pad in the federal wet locked-wheel braking test (49 CFR 575.104).
Does the UTQG traction grade tell me how a tire handles in snow?
No. It is a wet-pavement straight-line braking grade on asphalt and concrete. It does not test snow, ice, cornering or dry grip.
What does temperature grade A mean?
Grade A means the tire completed the 575 rpm stage of the federal heat test (about 115 mph on the 67.23-inch test wheel, by our arithmetic) without separation, chunking, cracking or pressure loss.
Are most tires graded A or AA for traction?
Yes. NHTSA says 15% of current tires are AA and 77% are A. In the full NHTSA file we downloaded, 17.5% of records are AA and 73.5% are A.
Look up real ratings
- 225/65R17 tires ranked by treadwear35 graded lines
- 235/55R19 tires ranked by treadwear32 graded lines
Sources
- 49 CFR § 575.104 Uniform tire quality grading standards, U.S. Code of Federal Regulations (eCFR). Retrieved 2026-10-25.
- TireWise: Tire Safety Ratings and Awareness, NHTSA. Retrieved 2026-10-25.
- Reading a Tire Sidewall, Tire Industry Association. Retrieved 2026-10-25.
- Tire Care Essentials, U.S. Tire Manufacturers Association. Retrieved 2026-10-25.
NHTSA ratings are from the dataset we publish. Maker statements are the makers’ own claims. We make no price claims. Found an error? See About & corrections.
Keep reading
- What does a tire treadwear rating mean?UTQG basics
- All-season vs. all-weather vs. winter tiresTire types
- How to make your tires last longerMaintenance