License plate working group R. Williams Request for Comments: 1 January 5 2003 Category: Standards track (draft) A Standard for License Plate Filenames (draft) Copyright Notice Copyright (C) Royce D. Williams (2003). All Rights Reserved. Abstract This document proposes a standard predictable format for naming of computer image and data files relating to license plates. The name will be primarly based on the unique properties of each plate. 1.0 Introduction ------------------------------------------------------------------------ 1.0.1 Guiding Principles ------------------------------------------------------------------------ Whenever possible, this standard will be most useful when it is based on what is visible on the plate rather than on any specialized knowledge of the purpose of the plate. However, since most plate collectors are aware of what major category a particular plate falls into, and since it is that categorization that needs to be facilitated by the standard, those categories are represented in the standard. 1.0.2. Requirements notation ------------------------------------------------------------------------ This document occasionally uses terms that appear in capital letters. When the terms "MUST", "SHOULD", "RECOMMENDED", "MUST NOT", "SHOULD NOT", and "MAY" appear capitalized, they are being used to indicate particular requirements of this specification. A discussion of the meanings of these terms appears in [RFC2119]. 2.0 Field Definitions ------------------------------------------------------------------------ Filenames shall be of one of the following forms: country-state-year-type[-subtype]_number.extension country-state-year-type[-subtype]_number_tagyear.extension country-state-year-type[-subtype]_number_custom.extension country-state-year-type[-subtype]_number_tagyear-custom.extension with fields defined and regulated as follows. All alphabetic characters in the filename MUST be lower-case. 2.0.1 Country of Origin ------------------------------------------------------------------------ The "country" field MUST be the two-character ISO country code. The country code MAY be omitted when it is unlikely that the filenames will come from multiple countries, but SHOULD be used whenever feasible to make file sharing easier. us-ak-1984-psg_bdt606.jpg 2.0.2 State or Province of Origin ------------------------------------------------------------------------ The "state" field MUST be the standard country-specific state or province code. When a license plate is based on some kind of national or international governance (such as military plates, consulate plates or other government plates), the country code is repeated in the "state" field so that proper sorting can occur. Native reservations that are customarily identified with a particular state/province should be categorized as if they were within that state. This standard does not address the issue of territories or entities that span national or international boundaries. 2.0.3 Issue and Registration Years ------------------------------------------------------------------------ The year MUST be a 4-digit year representing either the permanent issue year appearing on the plate or the latest registration year of the plate. If more than one permanent year appears on the plate because of a range of dates intending to represent years of authorized registration, the earliest year MUST be used. If more than one year appears because of a span of time displayed for commemorative purposed, the latest year MUST be used. When the plate has a permanent year, metal plate tabs and stickers MAY be ignored. If no year appears permanently on the plate, a sticker or visible registration year MAY be used. Plates that have neither a permanent nor a registration year SHOULD use a year or decade designator for sorting purpose based on the known year of issue for that type of plate. If the first year of issue of that type of plate is known, it SHOULD be used. [crufty example of AK plate decade prefixing] 196x - all '60s-era blue-on-white plates without permanent dates 197x - all '70s-era red-on-white plates without permanent dates 198x - all '80s-era blue-on-yellow plates without permanent dates 199x - all '90s-era gold rush plates without permanent dates (through DZZ) 200x - all '00s-era gold rush plates without permanent dates (starting with EAA) 2.0.4 Vehicle Type ------------------------------------------------------------------------ The vehicle type field MUST be either a primary vehicle type or a plate subtype. Primary vehicle types are: ctk - commercial truck ctr - commercial trailer gvc - government (county) gvm - government (municipal/township) gvo - government (other) gvs - government (state/province) hir - For hire (taxicabs) hst - Historic vehicle or collectible vehicle off - off-road, all-terrain or occasional-use mcy - motorcycle psg - passenger trk - non-commercial truck trl - trailer (non-commercial) otr - other unk - unknown Plate subtypes are: cns - consulate dlr - dealer edu - educational affiliation env - environmental support/protection ham - ham radio callsign han - handicapped sam - sample van - vanity vet - veteran If the "oth" (other) primary vehicle type is used, it MUST be followed either by a three-character subtype as listed below, or else the "Custom" field should be used to differentiate the plate. If a sample or vanity plate cannot be associated with a primary type, the "unk" (unknown) primary type SHOULD be used. If the primary type is not known, the "unknown" primary type SHOULD be used. In the absence of a primary type field, software or scripts MUST interpret this as the "unknown" type. 2.0.4.1 Specialized and Sample Plates and Plate Styles In states where multiple plate types are available that can only be distinguished from other plates by their appearance and not by their number, the custom field (2.0.6) SHOULD be used to make differentiation possible. 2.0.5 Number ------------------------------------------------------------------------ "number" MUST be the actual content of the plate. The number of the plate and the portion of the filename before and/or after the number but before the file extension MUST be bounded by underscores ("_"). In automated processing of the filename, the actual license number MUST be the only information between underscores (or between the left underscore and the right period). The following conventions are noted: * Spaces SHOULD be ignored * Dashes MAY be represented as shown or MAY be ignored * Modifications made to the plate by hand (apostrophes, etc) MUST be ignored * Special characters appearing on the actual plate MUST be represented with "^" * Grouping of major and minor incrementals MAY be represented with "=", as in "ak-1973_AAA=123.gif". * When logical grouping can occur based on a division between two portions of a number that does not conform to a standard sort order (such as "6981BR" appearing chronologically before "1234DR"), the portion that corresponds with the major incremental can be placed before the minor incremental, as in "ak-198x_br=6981.jpg". 2.0.6. Custom Area ------------------------------------------------------------------------ The "custom" area is unregulated by this document other than in its location and length. It SHOULD NOT exceed eight characters. It can be used to differentiate between otherwise similar plate names or for local purposes. 3.0 Examples ------------------------------------------------------------------------ A 1970 Alaska license plate with the year "70" permanently on the plate with 1972 and 1973 stickers and the contents "C8975" MUST have the filename: us-ak-1970_c8975_1973.jpg 4.0 References ------------------------------------------------------------------------ [RFC2116]