Recently, a significant advancement in Connected and Automated Vehicles (CAVs) is witnessed. Consequently, the development of the Vehicle-to-Everything (V2X) was arisen to establish the communication between the different agents in the system seeking some cooperative driving behavior. However, there is still a gap and various issues in handling the fleet of cars on highways due to the dynamic environment. Therefore, this paper proposes a new agent emergence in the transportation system that provides comprehensive cooperative behaviors. This agent is the Vehicular Convoy as an extension for the known platoons. However, this work is not only interested in studying the agent, but it also proposes a holistic Robotics Operating System (ROS)-based Cooperative Architecture for Transportation System known as (CATS). Three main agents -Car, Road, and Convoy- are combined in a unified framework, cooperating through the V2I/V2C/C2I paradigms. The archi-tecture involves the different behaviors and necessary modules for each agent solely, in addition to developing the corre-sponding inter-communication protocols. The architecture is validated using Webots on different scenarios that demonstrate the capability of creating many convoys simultaneously, with different joining scenarios. The architecture performance shows promising results in achieving various cooperative behaviors successfully with practical computational complexity.