A vehicle identification number, commonly abbreviated to VIN, is a unique code including a serial number, used by the automotive industry to identify individual motor vehicles, towed vehicles, motorcycles, scooters and mopeds as defined in ISO 3833. VINs were first used in 1954. From 1954 to 1981, there was no accepted standard for these numbers, so different manufacturers used different formats. In 1981, the National Highway Traffic Safety Administration of the United States standardized the format. It required all over-the-road-vehicles sold to contain a 17-character VIN, which does not include the letters I (i), O (o), or Q (q) (to avoid confusion with numerals 1 and 0). There are vehicle history services in several countries that can help potential car owners use VINs to find lemons and branded vehicles. See the used car article for a list of countries where this service is available.