International vehicle registration code system is used for vehicles belonging to the diplomats of foreign countries with license plate from the host country. That system is host country-specific and varies largely from country to country. For example TR on a diplomatic car in the USA indicates Italian, not Turkish. Such markings in Norway are indicated with numbers only, again different from international standards (e.g. 90 means Slovakian. International vehicle registration code The country in which a motor vehicle's vehicle registration plate was issued may be indicated by an international licence plate country code, formerly known as an International Registration Letter or International Circulation Mark.
Vehicle registration plates of Luxembourg series used 4000-4999 before DA followed with 5000 to 5999. The prescribed sequence of issue follows a pattern of ascending and descending alphabetical order of the two letters, as can be seen in the following list. When the first block of 1000 AZ numbers has been issued, we will presumably see the issue of BA5000. Note that certain letters (I and O) and combinations are excluded. The list should be read from top to bottom, left to right: Vehicle registration plates of Luxembourg Vehicle registration plates in Luxembourg bear a maximum of six characters. The standard series in use today