The National Highway Traffic Safety Administration (NHTSA) has issued a notice of proposed rulemaking (NPRM) on two amendments to the tire identification number (TIN), which must appear on virtually all new and retreaded motor vehicle tires sold in the United States.

First, because NHTSA is running out of two-symbol codes to identify new tire plants, NHTSA is proposing to expand the first portion of the TIN, known as the manufacturer identifier, from two symbols to three for manufacturers of new tires. This amendment would substantially increase the number of unique combinations of characters that can be used to identify individual manufacturers of new tires.

Second, NHTSA is proposing to standardize the length of the tire identification number to eliminate confusion that could arise from the variable length of tire identification numbers. This NPRM would standardize the length of the TIN at 13 symbols for new tires and seven symbols for retreaded tires,
making it easier to identify a TIN from which a symbol is missing.

Comments must be submitted by August 25.