In the early days of automobiles, the specific car's identifying number was called the chassis number or frame number. A tin plaque was stamped with the vehicle's specific number and displayed under the hood, usually on the top right of the firewall.
VIN numbers were first used in 1954 in the United States. The U.S. government asked auto makers to come up with a new standardized numbering system to identify vehicles. Up until then, manufacturers used engine numbers to register and title cars, trucks, and motorcycles. This became a problem if the motor was replaced, which was fairly common at the time.
From 1954 to 1981, there was no accepted universal standard for these numbers, so different auto and motorcycle manufacturers used different formats. Then, in 1981, the National Highway Traffic Safety Administration (NHTSA) standardized the format. It required that all on-road vehicles contain a 17-character VIN, which does not include the letters O, I, and Q to avoid confusion with numerals 0, 1, and 9.
VIN numbers on vehicles today are based on standards set by the International Organization for Standardization (ISO) in 1979. Compatible ISO standards have been adopted by the United States and the European Union.
