Peter Hall, a renowned British urban planning scholar, believes that the modern service industry, characterized by face-to-face exchanges and specialization, is undergoing a complex process of “centralized decentralization.” High-end producer services are on a broad urban regional scale. Diffusion, but at the same time reaccumulate on special nodes in the area. Therefore, the important hub areas of the regional public transport network, namely the areas where people flow, information and services are highly concentrated, are also the regions with the greatest potential for service industry development. The result of the development of many large cities in Europe for decades has been the formation of a three-level “regional CBD” based on the agglomeration of public transport hubs.
Level 1 CBD: The traditional CBD formed by agglomeration of high-end service industries (such as banking, insurance, government, and headquarters, etc.) is mainly located in the hub area of the city center, among which Osaka is the most prominent.
Level 2 CBD: New types of service industries (such as corporate headquarters, media, advertising, public relations, and design, etc.) are clustered into new CBDs within 5-8 kilometers of the core area.
Third-level CBD: Specialized CBDs that are formed by a specific specialized function (such as education, entertainment, sports, exhibitions, conferences, etc.) that are gathered within 35-65 km from the core area.