 All tires manufactured for sale in the United States since March 31, 1979 are federally mandated to have the UTQG ratings on their sidewall as part of the DOT approval process, in which non-DOT approved tires are not legal for street use in the United States.It is not to be confused with the tire code, a supplemental and global standard measuring tire dimensions, load-bearing ability and maximum speed, maintained by tire industry trade organizations and the International Organization for Standardization.The National Highway Traffic Safety Administration (NHTSA) established the Uniform Tire Quality Grading Standards (UTQGS) in 49 CFR 575.104.