This SAE Recommended Practice is intended to provide uniform nomenclature and definitions for the primary levels of vehicle identification@ with particular application to passenger cars. While this initial terminology applies only to passenger cars@ work is in progress to develop supplementary nomenclature and definitions pertaining to truck and/or commercial vehicle terms and terms presently used interchangeably in passenger cars@ trucks@ or commercial vehicle applications. These supplementary terms will be covered in subsequent revisions to this recommended practice.