The majority of communication systems are built on the principle of tw
o distinct parties communicating with each other. Dynamic traffic info
rmation and navigation systems, on the other hand, also embody the pri
nciple of area-based communication. Moreover, they demand the use of a
distributed communications network consisting of both fixed and mobil
e entities. This paper describes the general structure of the SOCRATES
Communication System, and shows how this structure is being applied i
n a 'live' GSM network for the purposes of field-testing the SOCRATES
concepts.