With significant advancements in information and communication technologies, connected and autonomous vehicles (CAVs) can provide improved transportation services. At present, a variety of technologies, such as vehicular networks, communication interfaces, and modern hardware devices enable CAVs to support reliable, safe, and quality transportation system options with improved performance and increased effectiveness. In this paper, we carefully explore a set of distinguished state-of-theart CAV systems with a focus on On-board Computational Unit (OBCU) hardware architectures, communication technologies, deployment challenges, and performance aspects. The exploration critically identifies important area transformations and anticipates future trends influencing CAV communications and processing requirements. To that end, we propose the design of a future generic OBCU architecture that can be customized with appealing features and used in CAVs.