The UTQG (Uniform Tire Quality Grading) index is a standardized grading system used to provide information on tire performance in three key areas: wear resistance, traction and temperature. It was created by the United States Department of Transportation (DOT) to help consumers make informed decisions when purchasing tires.

1. Wear resistance (Treadwear):
The UTQG rating for wear resistance is a number that indicates the expected life of the tire compared to a standard reference tire. This number is generally in the range of 60 to 800, with 100 being the benchmark. For example, a tire with an index of 200 should have a wear life approximately twice that of the reference tire. It is important to note that this rating is based on testing conducted under specific laboratory conditions and does not always reflect actual on-road experience.

2. Traction:
The traction rating evaluates the tire's ability to stop on wet roads. It is measured in three levels: AA, A, B and C. A tire rated AA provides the best traction performance in wet conditions, while C indicates lower traction. Levels AA and A are the most common and are found in tires with good grip on wet surfaces.

3. Temperature (Temperature):
The temperature rating indicates the tire's ability to dissipate heat generated while driving. It is measured at three levels: A, B and C. An A-rated tire has a better ability to resist heat and dissipate it properly, which is especially important during driving at high speeds or under heavy load conditions.

It is essential to understand that the UTQG index does not evaluate other important aspects of tire performance, such as grip in dry conditions, ride comfort or performance in winter conditions. Therefore, it is recommended to consider other sources of information and specific driving needs before making a tire purchasing decision. Additionally, UTQG ratings can vary by manufacturer, so it's essential to compare like-for-like products to get an accurate assessment.