The gradual evolution of autonomous driving technology will lead to the long-term coexistence of traditional vehicles and vehicles with varying levels of intelligence, which, accordingly, brings challenges in terms of traffic safety and efficiency. To address these issues, it is necessary to better understand the interaction between vehicles. This research aims to use mixed reality technology to create a transportation digital twin system, in order to study the interaction between vehicles in different traffic scenarios and explore the key factors that affect road safety and efficiency in mixed traffic scenarios. Mixed reality technology will be used to develop a digital twin system, which allows researchers to simulate different types of vehicles and traffic scenarios. By using mixed reality technology, researchers can observe traffic scenarios in real-time and interact with them. This approach will provide a more immersive and interactive research experience, enabling a better understanding of the interaction between vehicles.