This conference paper provides a comprehensive review of the latest research trends in Intelligent Transportation Systems (ITS) and Roadside Unit (RSU) design. ITS and RSUs play a pivotal role in modern transportation infrastructure, facilitating safer, more efficient, and sustainable mobility. This paper highlights key developments, emerging technologies, and research directions within these domains. We delve into topics such as vehicle-to-infrastructure (V2I) communication, edge computing for RSUs, AI-driven traffic management, and the integration of 5G and IoT into ITS. By examining recent advancements, this paper aims to contribute to the ongoing discourse on the future of transportation systems.