Study on warning, priority, prohibition and mandatory signs. Volume 1: final report. Volume 2: appendices. Volume 3: synoptic tables. Carried out on behalf of the Commission of the European Communities CEC, Directorate General for Transport DG VII.

In accordance with the vienna conventions and the european agreements, member states remain free to decide the form of their respective national codes and may add certain rules of their own. However, in view of the ever increasing international road traffic within the european community, it is desirable that, wherever possible, road signs should be harmonised between member states. This study identifies how the ec member state have interpreted and adapted the vienna conventions and european agreements, enabling the ec to possibly draft proposals to standardise regulations concerning road traffic signs which would minimise the misunderstanding of signs by residents of the member state concerned.