Monitoring Road Network in the Era of Big Data and Connected Vehicles Nour-Eddin El Faouzi French Institute of Science and Technology for Transport, Development and Networks Advances in Information and Communication Technologies (ICT) allow the transportation community to foresee relevant improvements for the incoming years in terms of a more efficient, environmental friendly and safe traffic management and operations. In that context, new ITS paradigms such as Cooperative Systems (C-ITS) enable an efficient traffic state estimation and traffic control. C-ITS refers to three levels of cooperation between vehicles and infrastructure: (i) equipped vehicles with Advanced Driver Assistance Systems (ADAS) adjusting their motion to surrounding traffic conditions; (ii) information exchange with the infrastructure; (iii) vehicle-to-vehicle communication. Therefore, C-ITS makes it possible to go a step further in providing real time information, enhanced real time monitoring and tailored control strategies to specific drivers. As a response to an expected increasing penetration rate of these systems, traffic managers and researchers have to come up with new methodologies that override the classical methods of traffic modelling and traffic control. This presentation will focus on the potentialities of C-ITS for real time Monitoring road network, traffic management with the methodological issues following the expansion of such systems. The research efforts reported here introduce, data assimilation and cooperative traffic modelling framework which constitute a building block for Cooperative Traffic Management (CTM).