International vehicle registration code

The display of a national distinctive mark on a white oval plate, 30 cm × 18 cm (12 in × 7 in) with black letters was first introduced by the 1909 International Convention with respect to the Circulation of Motor Vehicles signed in Paris.

According to the Vienna Convention on Road Traffic, the distinguishing sign of the country of registration must be displayed on the rear of the vehicle.

The requirement to display a separate distinguishing sign is not necessary within the European Economic Area, for vehicles with license plates in the common EU format, which satisfy the requirements of the Vienna Convention, and so are also valid in non-EU countries signatory to that convention.

[citation needed] SHS was for the Kingdom of the Serbs, Croats and Slovenes (Kraljevina Srba, Hrvata i Slovenaca).

There are unofficial codes in common use, such as "AS" for Asturias, "CAT" for Catalonia, "SCO" for Scotland, "CYM" for Wales (Welsh Cymru), "ENG" for England, "BZH" for Brittany (Breizh), "GRD" for Groland (a fictional/satirical 'presipality'), "FRL" for Friesland, "NB" for North Brabant, "VL" for Flanders (Vlaanderen), "V" for Vojvodina/Vajdaság, "TS" for Transylvania, "P" for Palestine, "PR" for Puerto Rico, "CSB" for Kashubia (Cassubia) and "SIC" for Székely Land (from Latin Terra Siculorum).

In addition, in some areas, vehicle-style stickers have been used to denote and promote other entities, such as towns, islands, businesses, and even associations.