1. Registration Number of Vehicles in International Traffic  The registration number of a vehicle shall consist either of figures or of figures and letters. The figures shall he in Arabic numerals as used in United Nations document and the letters in Latin characters.When other numerals or characters are used, they shall be repeated in the numerals or characters of the types mentioned above.

2. The number shall be legible in normal daylight at a distance of 20 m (65 feet).

3. When the registration number is displayed on a spacial plate, this plate shall be fixed in a vertical or nearly vertical position and in a plane perpendicular to the longitudinal axis of the vehicle itself. when the number if fixed to or painted on the vehicle itself , this shall be done on a vertical or nearly vertical  surface at the back of the vehicle.

4. The rear registration number shall be illuminated as prescribed in annex 6.


 Convention of Road Traffic signed at Geneva September, 19 1949 (English)