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 Europe do not need to display the white oval international vehicle registration code while within another member state. However, according to the small print of the French legislation, the specified size of the lettering is slightly larger than that used on UK plates. Several non-EU European states have implemented formats similar to the EU format, replacing the circle of stars with their own symbols. Vehicles with such number plates do not need to display the white oval international vehicle registration code while within countries signatory to the Vienna Convention on Road Traffic. Several countries have made efforts to avoid duplicating registration