Standard Radiation: A New Perspective Leading the Coordinated Development of Urban Agglomerations

Abstract

With the increased communication among cities, coordinated development between regions has become a common trend. An urban agglomeration is a special spatial structure unit, which becomes an important driving force for the coordinated development of the region through the radiation effect generated by the central city. The existing studies on regional integration have focused more on the economic, financial, and technological innovation radiation effects. However, as an essential tool for economic development, technological progress, and social governance, the standard plays an irreplaceable role in promoting regional integration and enhancing the coordinated development of urban agglomerations due to its ability to consensus and cooperation sharing. Therefore, based on the theories of growth pole, radiation effect, and city field, this paper first puts forward the concept of the standard radiation effect and argues that the standardization level of the central city can lead and drive the development of the urban agglomerations through the method of theoretical elaboration. Secondly, we explain the mechanism of the standard radiation effect in promoting the coordinated development of urban agglomerations under the interaction of multi-dimensional proximity. Finally, taking the Beijing-Tianjin-Hebei urban agglomeration, the Yangtze River Delta urban agglomeration, and the Guangdong-Hong Kong-Macao Greater Bay Area in China as typical cases, this research explores and summarizes three different models of the standard radiation effect, which are dominated by institutional proximity, economical proximity, and geographical proximity, respectively. The results of the study show that the standard radiation has a regional leading role. Furthermore, the effect of the central city in different urban agglomerations is dominated by different proximity, and there are different models and paths. Thus, in the process of regional industrial collaboration, it is necessary to focus on the standard cooperation among cities, and according to the characteristics of different urban agglomerations, make the most effective use of advantageous proximity to promote the development of regional integration. The conclusion can enrich the relevant studies on the agglomeration and radiation effects, give theoretical explanations on how the standard radiation effect of the central city leads to regional development, and provide new thinking perspectives and practical references on the way to achieve coordinated development of urban agglomerations.

1. Introduction

An urban agglomeration is a spatial form that emerges after the advanced stage of urbanization; they consist of a regional association of spatially connected, relatively dense groups of cities and towns with complex internal linkages and systemic structures [1]. As a new type of geographical space, urban agglomerations have gradually become core regions that support national economic and social development. The coordinated development of urban agglomeration is, therefore, an important aspect of healthy and sustainable regional development [2].

It has been shown that urban agglomerations are formed when a central city interacts with a number of cities of different sizes and levels; these interactions rely on specific natural conditions, transportation and information networks, and the industrial division and collaboration to drive the synergistic development of the urban system [3]. According to the theory of regional spatial structures, at the initial stage of the independent development of cities, the economic linkage between cities is not close, the city function is incomplete and weak, and the regional space is characterized by a primitive equilibrium state. Afterwards, the central city, which has superior geographical, political, and cultural conditions, experiences rapid development, and its agglomeration function is enhanced, attracting an increased population, capital, and industries; at the same time, the degree of spatial unevenness increases, manifesting as a core–edge structure [4]. Eventually, when the central city reaches a certain scale state, it shifts from attracting to the center to spreading around and radiating outward to the periphery, to achieve an overall balanced development [5,6]. This can be seen in the formation and development of urban agglomerations, both agglomeration and diffusion mechanisms play a very important role. The central city and the peripheral cities form a strongly interconnected whole through the flow and transfer of various elements.

The standard is the common implementation of generally accepted guidelines after discussion and consultation between particular stakeholders [7], and this is characterized by plurality, flexibility, efficiency, and replicability. Due to its important role in technological diffusion, the unified market, and government collaboration, the standard becomes an important tool for regional management and can effectively promote the coordinated development of urban agglomerations. In terms of technology, the standard can accelerate the application of advanced technologies and innovations in different spaces [8], and achieve industrial linkages between regions. In terms of markets, the standard can convey rules and information, break market barriers and local protections, and establish unified market rules [9]. In terms of governance, the standard satisfies diversified needs after contests involving multiple parties, and alleviates the contradiction between overall development and geographical divisions [10]. Therefore, it can be assumed that the standard is an issue that deserves more attention in relation to the development of urban agglomerations. However, until now, many scholars have discussed only the promotion of standards in terms of enterprises and levels of technological development, and their role in regional development in terms of regulation, unification, and coordination has not been systematically discussed. Based on the existing research, this paper offers a theoretical explanation of how standards, as a kind of soft connectivity, are a new mechanism for promoting regional synergistic development, which can accelerate the process of the coordinated development of urban agglomerations. Moreover, three typical examples of urban agglomerations in China are selected to prove that the mutual recognition and interoperability of the standard is a means of realizing regional integration, which can promote the free flow of regional elements and resources at a larger scale and on a deeper level.

This paper is organized as follows. In Section 2, we review the existing literature on urban agglomerations, standards, and standard diffusion. By sorting through the existing studies, we conclude that there is already some theoretical support for the link between standards, as a means of regional connectivity, and the coordinated development of urban agglomerations. Thus, in Section 3, we focus on the central city and make the innovative proposition that the central city can exert the standard radiation and diffusion effects; furthermore, we explain and illustrate this new concept, and launch a pioneering study. Section 4 specifically analyzes the practical actions of the three major urban agglomerations in China, using case studies and comparative analysis methods to summarize different models of the coordinated development of urban agglomerations led by the central city. This is a guiding principle for accelerating the healthy, stable, and sustainable development of urban agglomerations from different approaches in the future. In Section 5, we conclude with a discussion of the findings and potential contributions of the paper, and give a description of the limitations of and the future research directions opened up by this study.

2. Literature Review

2.1. Urban Agglomerations and Their Coordinated Development

With rapid advances in globalization and information, the decentralization of production and the centralization of management has led to a dramatic reorganization of the roles, spatial scales, and relationships of countries, regions, and cities. The competition between countries has gradually evolved into the competition between central cities and the urban agglomerations on which they depend [11]. The earliest source of the concept of urban agglomerations was the group of towns proposed by Ebenezer Howard; then, in 1957, Gottmann explicitly proposed the concept and theory of the Megalopolis, which paved the way for the study of urban agglomerations in the modern sense. With the integration of regional development and urban growth theories, two mainstream schools of thought have emerged: the European Polycentric Network City (POLY-NET) and the North American Mega-region. Since 1970, the New Public Management movement, represented by government reinvention, has been widespread in developed countries, decentralizing regulatory authority to regions in order to create new competitive advantages. At the same time, the challenges of cross-administrative and fragmented public affairs and governance render the traditional management by administrative boundaries unsustainable; moreover, the single-city development model is no longer sufficient to meet the existing state of development, and a change in the governance model is urgently required. In this context, urban agglomerations aim to realize the coordinated development of the region through effective cooperation [12]. Through the joint participation of multiple subjects, urban agglomerations can become consortia that break down administrative divisions, integrating resources and synergizing functions with the reorganization of spatial structures, and then forming a networked power pattern that crosses regional boundaries and transcends the authority of a single government [13].

Now, the coordinated regional development of urban agglomerations has become a hot topic in academic research. Such studies are divided into three main categories, one of which concerns the exploration of the current situation, problems, and the path for realizing the coordinated development of urban agglomerations [14]. The second category of research focuses on the evolutionary process of the coordinated development of specific urban agglomerations, analyzing the changings state of characteristics such as population, transportation, network spatial patterns, and regional scope [15]. The final category proposes discriminative criteria and measurement methods for the coordinated development of urban agglomerations [16], expanding from a single dimension of industrial coordination to multiple dimensions of industry, society, transportation, economy, and culture, to empirically analyze the level of coordinated development of urban agglomerations.

Thus, it can be seen that the coordinated development of urban agglomerations works to break down the geographical boundaries within given spatial parameters and induce elements to be able to flow freely among cities; by sharing resources and complementing advantages, this mode of development realizes the overall effect of development within urban agglomerations [17]. The coordinated development of urban agglomerations works to realize the free flow of elements across regions, as well as interaction and mutual assistance between cities, and to improve the level of integration. This not only depends on the resources and capacity of a single city itself, but is also closely related to the development of neighboring cities, which means that the spatial agglomeration and diffusion effect is increasingly important for regional development. The central city has the most powerful absorption and spreading ability, as it not only gathers rich talents and financial resources, and forms new knowledge, information, technology, and other resources through utilizing, transforming, and creating the original resources, but also drives the development of the neighboring cities through the advantages of technology, capital, and systems in the process of cooperation and interaction with these other cities.

2.2. Standard and Standard Diffusion Effect

As a collection of a series of technical specifications intended to reduce information asymmetry and improve the compatibility and synergy of participants, the standard solves the problem of interoperability and interchange, takes into account the interests of all parties, and can form a large-scale collaboration in promoting trade integration, encouraging the transformation of scientific and technological innovation, improving quality, optimizing social governance, and regulating market order [18,19]; all of these factors help to realize a larger scope and higher level of co-creation, co-integration, and sharing.

The standards, which are specified in the form of articles and texts, become an important condition for competition between enterprises and even between countries. Standards are the rules that regulate the behavior of organizations and can be applied within a certain spatial scope. As an important way to popularize technical standards, standards diffusion is essentially a process of product marketization based on technical standards, and its technological innovation results are adopted by members or organizations in the diffusion system over time, forming a network effect and then occupying the market [20]. The process of standardization is a concentration of technological capability because most of the technological knowledge is stored in patents and standards [21], and technological transformation behaviors, such as technology diffusion, technology transfer, and technology licensing, essentially constitute the dissemination and market circulation of standards and patents. Technology standards are competitively diffused in the market based on the path of alliance cooperation, technology trading, product learning, and talent flow [22]; the competitive mechanism is the network effect, and the focus is the installation base [23], which—with the help of ‘Bass Mode’—can describe the diffusion of the product or technology throughout the cycle [24]. This mode of diffusion places more emphasis on the adoption and implementation of standards, which are effectively disseminated and applied. For example, the ISO 9000 series of quality management system standards were developed by the British Standardization Institute (BSI), certified by the International Organization for Standardization (ISO), and then implemented globally, enabling transnational diffusion. ISO14001 relied on regulatory and coercive forces in the early stages of diffusion, while, in the later stages, it was driven by the power of norms.

Standard diffusion refers to the widespread application of standards among multiple subjects, emphasizing a kind of innovation diffusion relying on technology spillover. However, based on a regional study, this paper argues that the standard is an approach to regional governance, and its leading, regulating, and coordinating role is crucial to the coordinated development of urban agglomerations. The level of standardization development marks the competitiveness and influence of a city. Standard cooperation among cities of different levels and sizes can lead them to influence each other’s standardization levels by learning and imitating initiatives and behaviors, which provides a new method and platform for achieving mutual recognition and connectivity within the region. Thus, the concept of standard diffusion, which describes the dissemination and interaction of such standards among cities, is relatively one-sided, and it should, therefore, be extended and defined from a spatial perspective, emphasizing its spillover and driving effect in the region. Hence, this paper makes a pioneering attempt to create a new term, ‘standard radiation effect’, to explore its impact on the coordinated development of urban agglomerations from the perspective of regional spatial structure, in order to obtain a comprehensive understanding of the standard radiation effect.

3. A New Perspective: The Standard Radiation Effect and Its Formation Mechanisms in Leading the Coordinated Development of the Urban Agglomerations

3.1. Theoretical Basis of the Standard Radiation Effect

3.1.1. Growth Pole

The growth pole was first proposed by the French economist Francois Perroux, and was then continuously added to and developed by Boudeville, Lassay, and Myrdal. The core idea is that development and growth do not occur in all places at the same time or evenly in every area at the same pace, but first appear with different intensities in some growth points or growth poles, and then spread outward through different channels and have an impact on the whole economy. Gradually, the scope of the application of the growth pole shifted from abstract economic space to a geographical spatial relationship, considering economic space as the application of economic variables in or above geographical space, thus giving rise to the idea of a regional growth pole strategy. In the process of studying regional imbalances, growth poles, namely, the city centers of economic activities, manifest obvious economic agglomeration phenomena, and their radiation effect promotes the overall development of the region [25].

Initially, the formation of a growth pole requires agglomeration, which attracts capital, resources, technology, information, and talents from the surrounding areas, continuously accumulating favorable elements and creating an environment for achieving rapid and advanced development. When growth poles achieve high levels of development, the aggregation of elements may exceed their carrying capacity, resulting in rising land and labor prices, passive cost increases, and further declines in the profitability of their marginal products [26,27]. At this point, the radiation effect of the growth pole surpasses the original agglomeration effect [28], leading to the outward transfer of traditional industries and labor, whereby the surrounding cities take over the capital, talent, information, and other resource elements, thus gaining greater development potential. The current development model of the central city has transitioned from foregrounding the agglomeration effect to the radiation effect, which has become the consensus among the academic community.

3.1.2. Radiation Effect

Radiation is a concept originally derived from physics, whereby physical quantities in space move through the ‘field’ to carry out interactions of energy, information, and mutual conversion; as the energy emitted in different forms spreads outward, this is called the radiation effect. In the same way, when applied to the fields of geography and economics, the radiation effect refers to the flow and transfer of talents, capital, information, technology, and market elements from regions with higher development levels to regions with relatively low levels of development, in order to further improve the efficiency of economic resource allocation and drive the gradient development of lagging regions, affecting their economic development status, production and lifestyle, economic systems, and ideological concepts. Due to the economic, cultural, scientific, technological, and institutional advantages possessed by the central city, this process can enhance its comprehensive development capacity and form the radiation effect of urban agglomerations. The spatial proximity of a central city and its neighboring small and medium-sized cities can share benefits, and thus, contribute to the development of the whole region [29].

Of course, the radiation effect of the central city on the neighboring cities is different at different stages of development [30]. The main aspects of the central city radiation effect include the point radiation effect, the line radiation effect, the plane radiation effect, and the network radiation effect, which can also be divided into the national central city radiation effect and the regional central city radiation effect.

3.1.3. City Field

The ideas, laws, and methods of physics have been applied to the study of economic problems for many years. Scholars, including Sornette, Stanley, Matti, and Mimkes, have analogized economic systems with physical systems and built models of economic systems to explain and analyze economic phenomena. Economic physics became an emerging discipline. In classical physical dynamics, a field is a form of matter that has a specific spatial extent. For instance, the electric field is a physical field that exists around stationary electric charges and is capable of transferring the interactions between the electric charges. Likewise, urban agglomerations are complex systems composed of many economic agents, which interact, interconnect, and continuously change [31]. If a city is likened to a static electric charge, the mutual interaction between cities is similar to the interaction between one charge and another in the electric field, which creates a city field similar to the electric field. These energies can propagate and change in the city field, forming urban waves that influence urban development. In other words, each city is stationary, and has its own resource elements that are able to flow, exchange, and transfer in the process of an interaction. Thus, urban agglomeration can be regarded as taking place within the city field, which is similar to the electric field. Those resources and elements that the city possesses, and which can promote standardized development, can be considered as the amount of electric charge [32]. The central city acts as a source of electric charges and transmits energy outward; in other words, it has an effect on other cities. The interaction in an urban agglomeration is, in fact, the standard radiation effect, which can be expressed in terms of electric field intensity. The specific similarities are shown in

Table 1. Similarities between City Field and Electric Field.

Electric Field	City Field
Electric Charge	City
Amount of Electric Charge (q)	Resources and Elements that the City Possesses to Increase the Level of Standardization (Q)
Electric Field Intensity (E)	The Intensity of the Standard Radiation Effect of the Central City (RE)
Distance (r)	Spatial and Geographical Distance of the City (R)

.

3.1.4. Proximity

A great deal of research has been conducted on spatial proximity. Proximity refers to the common ‘category’ or ’group’ characteristic among different subjects, and this common characteristic is usually beneficial in terms of enhancing communication and cooperation between subjects. The concept of proximity originated from Marshall’s concept of the cluster economy. The cluster economy essentially describes the clustering of business institutions in geographical space, reflecting the geographical proximity within the cluster. Geographical proximity assumes that the radiation spillover effect decays with increasing geographical distance [33,34]. Since the 1990s, many scholars have researched proximity, which has led to the enrichment of the concept of proximity and gradually moved beyond the concept of geographic proximity. The French school of proximity dynamics breaks away from traditional economics by arguing that geographic space does not exist independently and that there are other dimensions of proximity [35]. By expanding the singular concept of geographical proximity to a multi-dimensional understanding of proximity, scholars have examined the relationships between cooperative subjects from a broader perspective, and have begun to focus on non-spatial proximity. Accordingly, they have constructed a proximity analysis system from multiple perspectives, on the basis that, in addition to geographical proximity, economic proximity, institutional proximity, cognitive proximity, organizational proximity, and social proximity can all enhance this mutual relationship [36].

At the same time, there are complex interactions between the various aspects of multi-dimensional proximity. They do not exist in isolation, but can either exert their influence independently or form different combinations and generate interactive effects, to enhance the efficiency of the spillover and radiation effects [37].

3.2. The Standard Radiation Effect of the Central City

The radiation effect is based on the central city’s economic strength, industrial structure, openness level, infrastructure, and technology level. It influences and drives the development of surrounding cities through economic radiation, political radiation, cultural radiation, etc. [38,39]. Economic radiation can be understood as an economic circle or economic belt formed by the central city being in close contact with the surrounding areas under the actions of the market mechanisms, thus promoting the balanced development of the whole regional economy [40]. Financial radiation shows that the financial center gathers a large amount of energy and then radiates towards the surrounding area through financial means and financing [41]. The process of innovation radiation implies the overflow of scientific and technological achievements in geographical space. Because this center has rich innovation resources and strong technological advantages, it makes an important contribution to improving the efficiency of regional cooperation and innovation [42].

By examining the concepts of different types of radiation effects, it can be seen that all of them emphasize that energy is emitted from the field source as the starting point, and then travels to all of the surrounding places. The principle of the standard radiation effect is actually very similar to this; when the central city is in a mature standardization construction state, this will naturally generate a certain gap between it and the surrounding lagging areas. Then, the central city can independently promote the overall improvement of standardization level through some specific channels, such as transportation, the economy, and personnel, leading to full regional consistency. Therefore, this paper defines the standard radiation effect on a regional scale, due to the existence of potential differences in the level of standardization in geographic space. The central city is a supplier to intermediate channels, spreading, diffusing, spilling over, and transferring those elements that facilitate the development of standardization, strictly following the law of distance decay, which is accompanied by the absorption and continued innovation of demanders until equilibrium is reached.

The performance characteristics of the standard radiation effect of the central city are as follows. First, the level and scale of the central city within the urban agglomeration influence the standard radiation intensity. The higher the level of the central city, the correspondingly larger the scale, the better the development system, the stronger the ability to carry out the radiation effect outward, and the wider the geographical scope of the radiation and drive to the surrounding area. Second, in the city cluster, due to the differences in the quantity and quality of the development resource elements owned by the central city and other cities, there will be a certain gap in the level of standardization, resulting in the phenomenon of the standard radiation effect. Therefore, the more obvious the gap between the standardization capacity of different cities in the city cluster, the more frequent the connections and communication, the better the effect of standard radiation effect, and the easier it is to achieve the coordinated development of the region.

3.3. The Mechanism of the Standard Radiation Effect of the Central City Leading the Coordinated Development of Urban Agglomeration

The standard radiation effect is a new perspective on the coordinated development of urban agglomerations. The central city continuously gathers people, products, capital, information, and other elements, and becomes a growth pole with a scale effect. Its extremely high level of standardization is representative and advanced, and neighboring cities are more willing to conduct standardization and cooperate with it. Different cities are connected and communicate with each other, thus, forming a city field. Similarly to the radiation effect in physics, in the process of standard cooperation between the central city and the neighboring cities, those elements (human flow, capital flow, information flow, technology flow) that can foster the development of the standardization level from the radiation source (the central city) spread to the outsides (the peripheral areas) through the radiation channel. Thus, this enhancement and driving effect shows the existence of a standard radiation effect in the central city.

In the beginning, different elements of technology, knowledge, talent, and capital flow in a disorderly and random way in different regions, and the central cities attract those resources due to their strong infrastructure and development environment. The gathering of these elements in the central city promotes the exchange of information and the collision of ideas, thus, stimulating innovative activities and enhancing the standardization capacity of the central city in an all-round and multi-channel way, prompting it to become a regional growth pole. With the development of the region, the absorption effect of the central city gradually becomes smaller than the spillover effect and then starts to exert the radiation effect, spreading out to more points. The surrounding cities will learn to imitate the central city to perfect how such flows occur. In this way, the standardization level of the surrounding cities is enhanced, and the overall development of the urban agglomeration is driven by one point; the specific process of element flow is shown in Figure 1.

The standard radiation effect, as a spatial behavior, can lead to the coordinated development of urban agglomerations through multi-dimensional proximity; the specific mechanism of the leading role of the standard radiation effect of the central city is shown in Figure 2. That is, the standardization level of the central city can produce a strong radiation and driving effect on the surrounding areas under the influence of the correlation and interaction of different distance dimensions, such as geography, technology, and systems, which promotes and guarantees the complementary advantages and joint development of the urban agglomeration.

3.3.1. Geographical Proximity

With the development of transportation and modern communication technologies, accessibility within an urban agglomeration promotes spatiotemporal compression. Geographic proximity creates opportunities for face-to-face contact and in-depth communication [43], which significantly influence the efficiency of tacit knowledge dissemination and uptake, thus, increasing the activity of standardized talent innovation cooperation within the urban agglomeration. It is easier to share the actual benefits of relevant technologies among innovation subjects such as enterprises, universities, and research institutions, forming a new state of benign interaction and mutual learning on a small scale [44]. Standards represent a specific form of knowledge sharing and creation [45]. Thus, through knowledge spillover, the standard can interact and communicate between different subjects either directly or indirectly, spreading unconsciously across geographical limitations and spatial associations.

3.3.2. Technological Proximity

Technological proximity and similarity, and the complementarity of technological structures between cities [46] can accelerate the process of the acquisition, integration, and coordination of knowledge and technology [47]. Homogeneous enterprises in the horizontal direction with the market competition, or upstream and downstream in the enterprise chain, are more likely to develop into industrial clusters because of interest. This can prevent the duplication of investments and wasting of resources [48], and accelerate the diffusion of technology, thus promoting regional linkages with industrial interconnections [49].

3.3.3. Economical Proximity

Economic distance usually refers to the economic gap between regions. Cities with economic proximity also have greater levels of similarity in terms of strength and characteristics [50,51], leading to more frequent cooperation and exchange between subjects. Similarly, their needs for standardized talents and resources are relatively similar, which creates a realistic feasibility for the flows of talents and resources, allowing for a more efficient use of technology and the adoption of similar measures.

3.3.4. Institutional Proximity

The reduction in institutional distance represents a more similar regulatory, normative, and cognitive institutional environment [52]. This institutional proximity can reduce the uncertainty of cooperation caused by institutional frameworks and administrative divisions in the social environment, providing a fundamental mechanism of trust [53].

Under the joint influence of these proximities, those elements that enhance the development of standardization levels can flow continuously through the government, enterprises, universities, research institutions, intermediaries, and other multi-participants. In the urban agglomeration, the central city can rely on the demonstration and imitation effect and the interactive exchange mechanism as a channel and platform to promote the dissemination of advanced technical achievements and successful management experience across the region; meanwhile, other cities apply and innovate after learning, which raises the standardization level. This radiation effect can promote the development of a region’s technology, talents, knowledge, information, markets, and capital; thereby, solving the problem of unbalanced development levels within a region and helping the urban agglomeration to achieve more efficient, more equitable, and more sustainable development.

4. Comparative Case Study of Three Major Urban Agglomerations in China

The conditions and processes of the formation and development of urban agglomerations vary significantly. Due to the composition of different numbers, characteristic types, and sizes of cities, the standard radiation effect of a central city in different urban agglomerations also shows its own unique features; likewise, the mode whereby coordinated development is promoted also differs for different regions.

In China, promoting regional integration is an important national strategy. The three major urban agglomerations of Beijing–Tianjin–Hebei, the Yangtze River Delta, and the Guangdong–Hong Kong–Macao Greater Bay Area are the earliest national urban agglomerations identified in China; now, they are also relatively mature urban agglomerations. They play an important leading and exemplary part in the country’s economic and social development. This paper takes these three urban agglomerations as the research objects, elaborates the specific practices of regional standardization construction in the central city of different urban agglomerations, and aims to summarize the patterns and paths of the coordinated development of urban agglomerations led by the radiation effect of standards.

4.1. The Beijing–Tianjin–Hebei Urban Agglomeration: A Coordinated Development Model Dominated by Institutional Proximity

The concept of the Beijing–Tianjin–Hebei urban agglomeration is developed from the capital economic circle, including the two metropolises of Beijing and Tianjin, as well as 11 prefecture-level cities in Hebei Province. The mechanism of the Beijing–Tianjin–Hebei urban agglomeration uses Beijing as a single growth pole to continuously promote institutional proximity in the city field as a way to drive the rise of Tianjin and Hebei. A detailed model is shown in Figure 3.

As the political, economic, and cultural center of China, Beijing has the optimal level of policies, industries, resources, and talents, and its overall competitiveness is much higher than that of other regions, making it a true growth pole. In 2011, the ‘Capital Standardization Strategy Outline’ pointed out the need to further strengthen standardization cooperation to promote the construction of the Beijing–Tianjin–Hebei urban agglomeration. Subsequently, the Capital Standardization Committee was established with its office in Beijing. More than half of these committees are from relevant departments and units in Beijing. Beijing has given CNY 15 million to 144 projects in 2022 in terms of standardization funding, requiring full use of the funds to promote standardization work. In 2014, the ‘Beijing–Tianjin–Hebei Quality Development Cooperation Framework Agreement’ proposed that the three regions strengthen communication and collaboration on standardization. In 2015, the Beijing–Tianjin–Hebei Regional Joint Development of Local Standards Conference Outline’ represented the further implementation of the regional coordination system of jointly formulated and separately published local standards. Later, the three regions also signed the ‘Beijing–Tianjin–Hebei Development of 100 Local Standards for Safety Production Cooperation Framework Agreement’, the ‘Beijing–Tianjin–Hebei Regional Engineering Construction Standards Cooperation Framework Agreement’, and the ‘Beijing–Tianjin–Hebei Regional Social Credit Standards Cooperation Framework Agreement’ to continuously improve the standard collaboration mechanism. By the first half of 2022, a total of 74 Beijing–Tianjin–Hebei urban agglomeration local standards had been jointly released, covering transportation, the ecological environment, government services, health, and human resources services.

Thus, the standard radiation effect of the Beijing–Tianjin–Hebei urban agglomeration takes Beijing, the central city, as the growth pole, promoting a unified policy system in the city field and regulating the behavior of different subjects. Through the signing of these cooperation agreements, exchanges and interactions between the cities have become more efficient, convenient, and flexible, effectively supporting the integration of related markets and infrastructures in the region by reducing ‘institutional distance’ and improving the level of integration of the urban agglomeration. The standard radiation effect of the central city of the Beijing–Tianjin–Hebei urban agglomeration is led by institutional proximity. Since national or regional institutions have an implicit influence on urban subjects [54], cooperative relationships among cities are more likely to emerge under the same institutional background [55]. Through the unified publication of policies, institutional proximity enables different subjects within an urban agglomeration to generate a common perspective based on mutual trust, which reduces conflicts in the process of standards cooperation and lowers the cost of the division and coordination, thus defining common goals and outputs of standards cooperation, contributing to the formation of a virtuous circle, and leading to the enhancement of regional capacity.

4.2. The Yangtze River Delta Urban Agglomeration: A Coordinated Development Model Dominated by Economical Proximity

As the core of the Yangtze River Delta, Shanghai attributes great importance to standardization work and vigorously implements standardization strategies; as such, its standardization influence continues to increase, and it plays the role of a growth pole within the radiation effect. In the city field of the Yangtze River Delta, the standard radiation effect gradually expands the scope of influence, based on economic integration, driving the urban agglomeration to achieve coordinated development. A detailed model is shown in Figure 4.

As early as 2000, the Shanghai, Zhejiang and Jiangsu provinces actively promoted the standards cooperation of the Yangtze River Delta region, based on the mutual recognition of standards, promoting the implementation of standards and other aspects of cooperation, solidifying the foundation of standardization development, and creating a new context for joint standardization work. After the Anhui Province was integrated into the Yangtze River Delta, the urban agglomeration held regular standardization meetings to clarify the focus of its regional standardization work and to jointly determine the framework of the integrated standard system in the Yangtze River Delta region. In recent years, 26 cities in the Yangtze River Delta have pushed forward regional standardization work in the areas of innovation, opening up, infrastructure, the ecological environment, and public services; they also released a series of regional standards using the unique ‘310’ number mark, and jointly established the international standardization Yangtze River Delta collaboration platform to achieve interconnection and interoperability.

Therefore, the standard radiation effect of the Yangtze River Delta urban agglomeration takes Shanghai as the growth pole to drive the development of nearby cities, initially forming a small spatial ‘core area–edge area’ spatial pattern. Then, it focuses on the urban agglomeration as a whole to extend the radiation range outward. Its multi-dimensional proximity primarily takes the form of economical proximity. Differences in economic development levels are often seen as important factors that influence cooperative relationships within a region, and the level of economic development of different cities largely determines their industrial structures and levels of technological development [56]. The closer the level of economic development of the surrounding cities to that of the central city, the more conducive the conditions are to the standard radiation effect, affecting the development of a larger range of regions. As the cities are characterized by industrial integration and comparable levels of economic development, the regional economic disparity has been decreasing; thus, the standardized system of the central city plays an exemplary and driving role and substantially promotes the coordinated development of the Yangtze River Delta urban agglomeration.

4.3. The Guangdong–Hong Kong–Macao and the Greater Bay Area: A Coordinated Development Model Dominated by Geographical Proximity

Since 2011, Guangdong Province, Hong Kong, and Macao have explored pathways for the standardized development of these three places. The Guangdong–Hong Kong–Macao Bay Area is different from the Beijing–Tianjin–Hebei and Yangtze River Delta urban agglomerations, as it has the characteristics of ‘one country, two systems’, and different economic policies and legal systems. For example, Hong Kong and Macao are not like Guangdong Province: there is no standardization authority in these government departments, but it is, instead, scattered across different departments. These regions also lack the function of standard development and publication, so they need to directly adopt international standards or advanced foreign standards. This means that regional standardization cooperation in the Guangdong–Hong Kong–Macao Greater Bay Area relies more heavily on a market-oriented approach for building cooperation models and creating a comprehensive transportation network in order to closely organize related communication and interaction activities.

On the map, the four central cities in the Guangdong–Hong Kong–Macao Greater Bay Area are located very close to each other. In this city field, a rapid transportation network with high-speed railroads, intercity railroads, and high-grade highways has been built, and the travel time between major cities is limited to within one hour. The advantage in terms of transportation makes the standard radiation effect more likely to occur. Shenzhen was the first city in the country to release the implementation of a standardization strategy outline, through the development of special activities, the creation of a standardization pilot, and the effective promotion of implementation, giving full play to the role of standard leadership; it, therefore, became the ‘Shenzhen Sample’. Guangzhou also actively carries out various forms of thematic activities and popularized standardization knowledge, spreading the concept of standardization; a number of various types of standardization pilots at all levels are ranked first in Guangdong Province. Hong Kong and Macao encourage relevant social groups, enterprises, universities, standardization experts, and professionals to participate in the promotion of standards through ‘connectivity, coherence, integration’. As Guangzhou, Shenzhen, Hong Kong, and Macao are, geographically, very close to each other, they jointly established the Guangdong–Hong Kong–Macao Greater Bay Area Science and Technology Innovation Association Standards Service Platform, the Guangdong–Hong Kong–Macao Greater Bay Area Standards Innovation Alliance, the Guangdong–Hong Kong–Macao Greater Bay Area Standards Promotion Association, and other organizations. Moreover, certain key areas were selected to develop a number of association standards in order to accelerate the interoperability and interconnection of standards in the Guangdong, Hong Kong, and Macao Greater Bay Area.

In summary, the Guangdong–Hong Kong–Macao Greater Bay Area has multiple growth poles and relies on a complete transportation network to achieve geographical proximity, which makes it easier to bring together the surrounding industry associations and chambers of commerce, and promote standard cooperation in the region. The model of the standard radiation effect of the Guangdong-Hong Kong-Macao Greater Bay Area is shown in Figure 5. Geographical proximity reflects the distance between regions, which is not measured solely by spatial distance but also takes into account the time and cost of dissemination and transportation [57]. This leads to cities being more willing to look for other city subjects in adjacent areas for cooperation and interaction; that is, the closer the geographical location between cities, the more obvious the standard radiation effect, the more convenient the channels for the flow of products and elements, and the higher the probability of integrated regional development. By giving full play to the comparative advantages of each region, the Guangdong–Hong Kong–Macao Greater Bay Area has handled the relationship between the government, enterprises, and the market more efficiently, and enhanced the overall development of the urban agglomeration.

5. Conclusions and Summary

5.1. Conclusion and Discussion

Standards as an important instrument of regional management have been overlooked by academics, and few studies have yet specifically explored the role they play in regional development. The standard radiation effect, as a new way of conceptualizing spatiotemporal spillover in regional development, relies on the central city playing a leading role in the process of the coordinated development of urban agglomerations. First of all, this paper examines the standard radiation effect from the perspective of its leading role in the coordinated development of urban agglomerations, and reveals how the standard radiation effect coordinates the development of cities and promotes regional integration. Next, we theoretically elaborate on the process of the standard radiation effect of the central city in leading the coordinated development of urban agglomerations. Finally, the specific situation of three typical major urban agglomerations in China is analyzed. The findings of the study are as follows:

(1)

As an important spatial carrier of social and economic activities in a certain region, the central city generates a radiation effect due to its highly developed standardization level. The standard cooperation and interactive activities between the central city and the neighboring less-developed cities can form a city field. In this field, the central city plays the role of a growth pole and promotes the free flow of resources and elements under the joint influence of the interaction of geographical, technological, institutional, and other multi-dimensional distances, thus leading to the overall development of the urban agglomeration.

(2)

The case of typical urban agglomerations in China illustrates that the leading role of the standard radiation effect from the central city in different urban agglomerations is dominated by different dimensions of proximity, and there are different patterns and pathways. The different types of multi-dimensional proximity play different roles in terms of size, with the result that the leading role of the standard radiation effect has different characteristics in different urban agglomerations. It can be specifically divided into the coordinated development model dominated by institutional proximity, economic proximity and geographical proximity.

5.2. Implications and Limitations

As a result, we make the following recommendations. First, the relevant departments and organizations responsible for the standardization planning of cities should recognize the important position of the central cities, and pay attention to the leading role of the standard radiation effect of the central city on the coordinated development of the urban agglomeration, so that they can make accurate and effective policies in the field of standardization in the future. On the one hand, it is necessary to determine the target positioning of the central city and improve the regional spatial layout. On the other hand, this approach encourages the diversification of standard cooperation within the urban agglomeration, as well as flexible cooperation methods and contents. Second, it is necessary to focus on multi-dimensional proximity in the development and construction of cities. It is not only important to actively improve the transportation capacity of cities, promote the rational layout of transportation networks such as airlines, railroads, highways, and waterways, and implement major infrastructure projects; it is also important to strengthen economic and technological ties between cities and push for regional industrial collaboration, and to jointly solve crucial technical problems, improve the level of integration concerning division and collaboration, enhance scientific and technological innovation, and ultimately achieve coordinated urban development. Therefore, attention should be paid to the leading role of the standard radiation effect of the central city, and efforts should be made to promote standard cooperation among cities to fit the need for coordination and coherence within the urban agglomeration and ultimately achieve the sustainability of regional development.

Our research can provide a set of insights and help define a further research agenda. Despite the importance of this study, it has limitations and may require further research. The paper offers a tentative theoretical discussion, case studies, and comparative analysis of the new perspective of the standard radiation effect, but does not empirically explore the role of how the standard radiation effect of the central city leads and drives the coordinated development of urban agglomeration. Our subsequent research will take China as an example and select several urban agglomerations for analysis. We will use the electric field model of physics as the basis to derive formulas for measuring the intensity of the standard radiation effect of the central city and determining the radiation range of different urban agglomerations. At present, we have collected specific data from 157 cities in China and completed the evaluation of the standardization level of each city; additionally, we have measured the multi-dimensional proximity distance between cities to observe the evolution law of the standard radiation effect of the central city of the urban agglomeration. This paper mainly comprises a theoretical description, which seeks to introduce a new perspective, while future research can offer more details and help to generate further insights.