<p>This article discusses the research progress of flow control technology in reducing road vehicle drag in the context of energy scarcity and climate crisis. Flow control can effectively reduce the aerodynamic resistance encountered by vehicles during operation, providing new solutions for improving vehicle power and fuel efficiency. This review provides an overview of the literature on how flow control changes the aerodynamic characteristics of road vehicles (such as squareback, fastback, and notchback). Firstly, this article compares the drag reduction effects of different flow control devices installed at different vehicle positions. Among them, active flow control and synthetic jet control of ordinary blowing/suction flow can usually reduce the resistance of road vehicles by about 10%, while micro-jet and plasma jets can only show significant drag reduction characteristics under high-speed conditions. Passive flow control devices such as deflectors, tail fins, and vortex generators can achieve a maximum drag reduction rate of nearly 30%, or increase lift at the cost of increasing some drag. Combination flow control can achieve higher drag reduction effects than a single control method. Secondly, this article provides an overview of the integration of closed-loop control and flow control, and delves into how advances in computing power and machine reinforcement learning will greatly enhance the future achievements of road vehicle drag reduction research. Finally, the development prospects and future directions of different types of flow control technologies were discussed.</p>