Recent years have seen the development and the emergence of new Cooperative Intelligent Transportation Systems (C-ITS) where data sent via Information and Communication Technologies (ICT) has a potential to enhance traffic conditions instead of extending physical infrastructure, thereby introducing new business models and reduction of environmental impact. These technologies along with the introduction of new features in the Advanced Driver Assistance Systems (ADAS) bring new challenges in terms of evaluation and performance of Connected & Automated Vehicles (CAVs). Key aspects such as policy design, field operational test design, acceptance of the (C-ITS) services and scalability of these services contribute a better assessment for reliability at the implementation tests. This talk provides an overview of general framework to perform the evaluation of new C-ITS by integrating these aspects into a 3 stage framework. An initial proposition of this simulation framework has been introduced via multi-agent systems that integrate interactions of physical, communications, and trust layers when deploying C-ITS services. It concludes by introducing fundamental challenges in terms of new approaches to maintain privacy of users who contribute data for enhancing these services and incentives to achieve better harmonisation in between new technologies, C-ITS and their deployment in real scenarios.