The traffic system is transforming into a highly complex system of systems with increasing connectivity and automation. Engineering such a system of systems requires close interaction between related stakeholders including authorities, car manufacturers, and the service and technology providers, both from the organizational and technical perspective. This paper describes a cloud-based traffic control system that provides a platform to support cross-sector interoperable information sharing, and data intelligence for future connected and autonomous vehicle integration. The system is engineered from a system of systems perspective with multi-stakeholder engagement and is designed to be cloud-native for stakeholder and service scalability. The paper discusses the motivation of the system, followed by a detailed description on the system architecture and the constituent systems. Supported services are presented with their working process, information flow, as well as their public demonstrations.