Traffic design systematically optimizes the functionality and performance of existing and future transportation systems and facilities. Positioned after traffic planning and preceding traffic management and services, traffic design is crucial for achieving the optimal utilization of transportation systems and facilities. It holds equal significance to urban design and industrial design. With the implementation of the nationwide “Smooth Traffic” plan by the Ministry of Public Security and the Ministry of Housing and Urban-Rural Development (formerly the Ministry of Construction), in the year 2000, traffic design theories and methodologies have been formally introduced and continuously developed and promoted in China. Its role and value have become increasingly prominent with the growing need for refined road traffic construction, as well as urban restoration and updates. The resulting benefits of optimizing and enhancing transportation systems have gained global recognition. This paper systematically outlines the development history, representative achievements, and the latest progress in traffic design technology. Addressing four main technical challenges, including the intensification of supply-demand conflicts, the enhancement of transportation development quality, the miniaturization and intelligence of new models of vehicles, and the uncertainties of traveler behaviors in a connected information environment, this paper identifies the future directions of traffic design technologies. With the goal of realizing the strategy of building a strong transportation nation where “people enjoy their journeys, and goods flow smoothly”, this paper puts forward development strategies from five aspects, including construction processes, administrative mechanisms, fee standards, standards and regulations, and professional qualifications.