The "DOT" symbol on commercial tires certifies the tire manufacturer's compliance with the U.S. Department of Transportation (DOT) National Highway Traffic Safety Administration (NHTSA) tire safety standards. The DOT serial number is located on the inside sidewall near the rim. The letters “DOT” are followed by eight to thirteen letters and/or numbers that identify where the tire was manufactured, tire size, and the manufacturer’s code, along with the week and year the tire was manufactured.
The "DOT" symbol on commercial tires certifies the tire manufacturer's compliance with the U.S. Department of Transportation (DOT) National Highway Traffic Safety Administration (NHTSA) tire safety standards.
Tires that are retreaded must display the retread manufacturer's D.O.T. code on the sidewall. This is often placed in the area reserved for branding, or near the tire's original D.O.T. code. Each time a tire is retreaded, it must be branded with a new code.