CONVENTION ON ROAD TRAFFIC
The Contracting Parties, desiring to facilitate international road traffic and to increase road safety through the adoption of uniform traffic rules, have agreed upon the following provisions:
Chapter III
CONDITIONS FOR THE ADMISSION OF MOTOR VEHICLES AND TRAILERS TO INTERNATIONAL TRAFFIC
ARTICLE 37
Distinguishing sign of the State of registration
1. Every motor vehicle in international traffic shall display at the rear, in addition to its registration number, a distinguishing sign of the State in which it is registered.
2. Every trailer coupled to a motor vehicle and required under Article 36 of this Convention to display a registration number at the rear shall also display at the rear the distinguishing sign of the State where the registration number was assigned. The provisions of this paragraph shall be applicable even if the trailer is registered in a State other than the State of registration of the motor vehicle to which it is coupled; if the trailer is not registered, it shall display at the rear the distinguishing sign of the State of registration of the drawing vehicle except when it is travelling in that State.
3. The composition of the distinguishing sign referred to in this Article, and the manner of displaying it, shall conform to the requirements of Annex 3 to this Convention.