Speed measurement is essential for the development of Intelligent Traffic Systems (ITS), and the adoption and enforcement of appropriate speed limits are among the most effective strategies to improve road safety. This review offers an exhaustive exploration of vehicle speed measurement methods and technologies within traffic applications. While inductive loop detectors and radar are mature technologies in traffic speed measurement, cameras are typically used to facilitate license plate recognition. This paper delves into the principles and technologies behind traditional speed measurement systems such as inductive loop detectors, wireless radar, LiDAR, and the Global Positioning System, alongside computer vision-based speed measurement. It examines the evolution of computer vision, reviews common datasets, and explores the feasibility of using cameras for direct speed measurement. Furthermore, this paper evaluates the precision, cost, and practicality of these technologies and discusses future research directions, providing crucial references and guidance for advancing Intelligent Traffic Systems.