This paper introduces a modular ontology supporting a car advanced driver assistance system (ADAS). Such a system is aimed at making road transport more efficient and effective, safer and more environmentally friendly.

ADAS usually implements applications such as intelligent speed adaptation, including static (new roads, speed limits changed by authorities), temporary (road works, schools) and dynamic (traffic responsive, road and/or weather conditions) speed limits and cooperative early information that is shared in (almost) real time among vehicles and infrastructures in critical conditions. There are already several ADAS implementations, made by different manufacturers or carried out in the context of research projects. The aim of this paper is to show the role of ontologies in enabling semantic interoperability in order to allow cooperation between the road infrastructure and assisting the driver to perform certain traffic related actions also increasing the infrastructure efficiency.

We define five domain ontologies for the purpose of supporting ADAS: Vehicle Security, Road and Traffic Security, Meteorological, Users' Profiles and Travel. The last one reports concepts concerning a given travel (departure, destination, vehicle, road) and imports concepts from the other ones. We emphasize the role of ontologies in enabling semantic interoperabilty in such an intensive knowledge-processing contexts.