This Technical Specification presents a system of standardized codes for existing signs and pictograms used to deliver traffic and traveller information (TTI). The coding system can be used to form messages to be handled by respective media systems, graphic messages on on-board units, and media system information on TTI dissemination systems (VMS, PC, PAT, etc.) (including graphic data). These types of information are required by travellers for their pre-trip planning as well as their in-trip plan modification based on information obtained through media systems.

As shown in Figure 1, a system handling graphic messages generally comprises TTI system operators, media systems and communication networks interconnecting these systems.