The use of cooperative ITS communication systems, supporting driving through the dynamic exchange of Vehicle-to- Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) messages, is a potential candidate to improve the economical and societal welfare. The application of such systems for novel cooperative traffic management strategies can introduce a lot of beneficial effects not only for road safety, but also for the economy related to transportation systems and the environmental impact. Despite this apparent set of promising features, City Road Authorities, which hold a key-role in determining the final adoption of such systems, still look at cooperative systems without sharing a clear opinion. This is mainly due to the current lack of definitive and solid evidences of the effectiveness of such systems when applied in the real world. In order to fill this gap and let Road Authorities estimate the usefulness of such technologies in achieving the objectives dictated by cities’ traffic management policies, the EU consortium iTETRIS is developing a simulation platform for large scale testing of traffic management solutions making use of cooperative ITS systems. Thanks to its own distinguishing features, iTETRIS aims at becoming a good supporting tool for Road Authorities to implement preliminary tests on the effectiveness of ITS solutions prior to investing money for the physical deployment of the communication infrastructures allowing their functioning.