iTETRIS: Adaptation of ITS Technologies for Large Scale Integrated Simulation The European Union (EU) Framework Program 7 (FP7) funded project, iTETRIS (An Integrated Wireless and Traffic Platform for Real-Time Road Traffic Management Solutions) targets to extend state of art in simulation of wireless vehicular cooperative systems for evaluation of road traffic management services and applications. In particular, iTETRIS addresses four important and distinct challenges: (a) road traffic and wireless integrated open-source simulation platform, (b) large scale trials, (c) realistic Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communication simulation and (d) dynamic, distributed and self-autonomous Intelligent Transport Systems (ITS) applications based on cooperative systems. iTETRIS will provide a standard compliant, open-source integrated communication and traffic platform suited for large scale scenario simulation. This Paper addresses extension of traffic simulator being used in iTETRIS, scalability studies of networking simulator, which have been achieved as project results. Further the paper presents the adaptation of the Intelligent Communications for Transport Systems (ICTS) reference architecture functionalities being developed by the European Telecommunication Standard Institute (ETSI) at its Technical Committee (TC) on ITS.