Availability and Adequacy of Facilities in 15 Minute Community Life Circle Located in Old and New Communities

Abstract

The 15 minute Community Life Circle (15 min-CLC) concept is an urban planning approach that aims to provide various daily services for citizens within a short distance. It has been widely adopted in China, especially in large cities. However, there is a lack of research on how to apply the 15 min-CLC concept in second-tier cities, which have high population densities and lower quality of life. This study chose Jinan City as a case study to explore the underdeveloped areas and facilities of 15 min-CLCs in rapidly developing and medium-size cities, called second-tier cities. First, it analyzed the distribution of facilities and residential POIs in old communities, new communities, and the whole city, to find out which types of facilities are missing at the community level. Second, it examined the relationship between facilities and population in each 15 min-CLC by using the Facility to Population Ratio (FPR), to evaluate the sufficiency of facilities to meet the daily needs of residents. Through the analysis of facility distribution and Facility to Population Ratio, our study found that old communities have all the required facility types within each 15 min-CLC, but they do not have enough number of facilities to support the population. At the same time, identified the underdeveloped regions and provided specific development directions for each 15 min-CLC. The FPR methodology developed in this study can be used to evaluate whether the existing facilities can meet the daily needs of residents in a certain region.

1. Introduction

The pursuit of a high-quality daily life has become increasingly important as economies development and continuous increasing of population [1]. To meet these demands, countries worldwide are exploring various strategies to create comfortable living environments for their citizens. Tobler’s law states that the interaction between two places decreases as the distance between them increases [2]. This distance can create barriers or costs in terms of time, money, and effort, which can affect the well-being of the people. Recently, one such strategy gaining popularity is the concept of the “15 min Community Life Circle” (15 min-CLC). This concept attempts to overcome the inconveniences brought by distance and emphasizes the provision of essential services within a walkable distance, particularly catering to the needs of the elderly [3]. The 15 min-CLC concept aims to improve residents’ quality of life by offering convenient access to essential services, which enhancing basic services and creating a healthy, safe, and appealing urban environment [4]. Moreover, the 15 min-CLC strategy is closely related to the smart city concept, as they both share the vision of achieving sustainable urban development and improving quality of life for residents. The 15 min-CLC strategy needs the technological support of smart cities to increase the convenience and diversity of services [5]. Smart cities also need to learn from the 15 min-CLC strategy to create more human-centered and inclusive urban spaces [6].

The implementation of the 15 min-CLC concept has gained acceptance in many Chinese cities and is gradually being incorporated into local urban planning efforts. Notably, the Shanghai master plan of 2016 recognized a 15 min CLC as a fundamental unit for community development, ensuring that essential daily services are within a 15 min walking distance for residents [7]. Furthermore, the Standard for the Planning and Design of Urban Residential Areas (GB50180-2018) that was issued by the Ministry of Housing and Urban–Rural Development of China in 2018, recommends that residential areas meet residents’ basic life demands within a reasonable walking distance. These guidelines advocate for the establishment of community life circles based on the residential area sizes, namely, 15 min, 10 min, and 5 min, with the 15 min-CLC being the most commonly adopted [8]. In addition, these existing guidelines mention the goals of developing the 15 min-CLC concept: the formation of convenient daily services; humanistic care for the elderly; education for all ages; diverse recreation, sufficient medical and health care; employment and management facilities; balanced public spaces; and a healthy environment [7,8].

Chinese cities are commonly classified into several tiers based on their economic development, population, and administrative importance [9]. The most advanced and prosperous cities are the first-tier cities, which are also major metropolitan with dense populations, modern facilities, and fast economic growth. Examples of first-tier cities are Beijing, Shanghai, Guangzhou, and Shenzhen. The second-tier cities are smaller than the first-tier cities, but they still play an important role in the economy and have a lot of influence in their regions. The third-tier cities are smaller and less developed than the first and second-tier cities. They usually specialize in local industries and provide essential services for agriculture, manufacturing, and other sectors in their areas. Some examples of third-tier cities are Lanzhou, Nanchang, and Fuzhou. There are also lower-tier cities, which are the smallest and are less economically developed [10].

Many previous studies have explored how the 15 min-CLC concept can enhance the quality of life of residents in first-tier cities. However, second-tier cities also face rapid economic development and urbanization, as many people move to urban areas for better job opportunities [11]. This migration increases the demand for housing, infrastructure, and public services [12]. Therefore, several local governments in second-tier cities have proposed in their urban master plans to adopt the 15 min-CLC concept to satisfy the daily needs of residents and improve their quality of life. Yet, there is a lack of research on how to implement the 15 min-CLC concept in second-tier cities [4,13,14,15]. Unlike the well-developed first-tier cities, second-tier cities that are still undergoing fast development have substantial economic strength and a large population, but they also encounter unique challenges such as uneven development across different regions of a city [16]. Therefore, the development practices and experiences of first-tier cities may not be directly transferable to these second-tier cities [17]. It is essential to apply the 15 min-CLC concept appropriately to developing cities, including second-tier and even lower-tier cities.

Jinan City is a unique example of a second-tier city that integrates the 15 min-CLC concept with its urban development. It has devised a practical development plan to apply this concept. This research analyzed Jinan City’s case and explored the prospects of the 15 min-CLC concept in other Chinese second-tier cities. The implementation plan of the 15 min-CLC concept in Jinan City can provide useful insights and lessons for other developing cities with similar goals.

The primary objective of this research is to identify underdeveloped areas and facilities by analyzing the distribution characteristics of facilities in both old and new communities within the 15 min-CLCs of Jinan City. The remainder of this research is structured as follows: Section 2 provides a review of previous studies and described the study area, data sources, and research methods. Section 3 shows the results and discusses their implications. Finally, Section 4 concludes this research.

2. Materials and Methods

2.1. Literature Review

The concept of 15 min-CLC has gained attention and application in various cities around the world recently [5]. For instance, Paris has proposed implementing a 15 min city concept in 2020. The C40 Cities Climate Change Leadership Group in 2021 discussed the 15 minute cities. The report emphasized the importance of easy access to goods and services, including markets, fresh food, and healthcare, for all communities [18,19,20]. China is planning to transform urban neighborhoods into 15 minute cities as well. Shanghai, as the first city in China to introduce the 15 min-CLC concept, has developed strategies that serve as a valuable experience for other Chinese cities. With the encouragement of the Chinese central government, more and more Chinese cities are considering integrating the concept of 15 min-CLC into their urban development plans such as Beijing, Guangzhou, Shenyang, Hefei, and Jinan.

In addition, the concept of a 15 minute city has also been extended to different scales in the process of practical implementation due to the unique context of different cities [21,22,23]. For example, Portland has created a convenient and safe 20 minute neighborhoods, where residents have access to various daily facilities such as transit, shopping, quality food, schools, parks, and social activities [24]. Similarly, Melbourne have advocated for a 20 minute block plan, which includes a return trip, requiring a 10 minute walk from home to their destination [25]. Some researchers have proposed that a 20 minute city, where individuals can reach their destination within 20 min by walking or using public transportation [26].

Previous studies have focused on advocating the fulfillment of residents’ basic daily needs within a 15 min walking distance and exploring successful implementation strategies of the 15 min-CLC concept from various perspectives.

Firstly, some researchers have combined various facilities and walking distances for analysis. For example, Logan (2022) analyzed the optimum distance of the 500 largest cities in the USA and 43 urban areas in New Zealand. They calculated the walking time of residents to different amenities through several methods based on the 15 min-CLC concept. They then identified the most important amenity types to assist planners in determining the scopes of communities in various cities, such as geographic boundaries [27]. Graells-Garrido (2021) analyzed the relationship between the distribution of service facilities and human mobility by quantifying the accessibility of facilities and found out the factors that affect the walking distance of residents within the neighborhood level in Barcelona’s 15 min-CLCs. They discovered that specific local services, such as educational and commercial facilities, impact human mobility at the community level in Barcelona [28]. Noworól (2022) discussed the urban layout of Krakow as a 15 min city, analyzing the geographical proximity of different facilities and the number of residents within different walking distances. They also explored factors affecting the population distribution within 15 min-CLCs [29]. These studies were aimed at the city-level analysis, providing insights for the overall 15 min-CLCs development in a city.

Secondly, some researchers have analyzed the distribution characteristics of various basic facilities that meet the needs of residents. For example, Song (2022) adopted the 15 min-CLC concept to analyze the spatial accessibility of healthcare services in Guangzhou’s 15 min-CLCs and evaluating whether the existing health services meet the daily needs of residents. The result shows that only 39.6% of residents can access to medical services within a 15 min of travel time. They redefined the service areas through optimal supply–demand (OSD) allocation to ensure equitable access [30]. Li (2019) analyzed the layout of service facilities in Baoding City based on POI data by calculating the up-to-standard rates, revealing insufficiencies in public cultural and elderly care facilities in Baoding City. Their research proposed optimization approaches based on shared and mixed functions, considering population structure, to address facilities that did not meet the standards [13]. Wu (2021) incorporated people’s needs into the 15 min-CLC evaluation model of Shanghai’s 15 min-CLC. They estimated the existing situation and conducted service area analysis through the kernel density estimation, identifying underdeveloped regions with mismatched basic service facilities and population distribution [31]. These studies focused on individual 15 min-CLC at the community-level and tried to improve each 15 min-CLC by considering individual differences.

The integration of city-level and community-level analysis is essential as it allows for a broader perspective on the development of 15 min-CLCs. City-level analysis helps to improve the overall planning and policies of a city, as different cities may have different priorities and histories of service facilities [27,28,29]. Community-level analysis focuses on the specific needs and gaps of each 15 min-CLC unit and suggests appropriate strategies for improving various facilities [30,31]. Therefore, our research applied both levels of analysis to the 15 min-CLC concept, to enhance the city-wide policies and the local development directions for each 15 min-CLC.

2.2. Methodology

Our research proposed a methodology that evaluated the current situation of facilities in second-tier cities from both city-level and community-level perspectives to identify the underdeveloped areas and facilities in the 15 min-CLCs. Our evaluation process consisted of two steps: first, assessing various facilities at the city-level to find out which ones were underdeveloped; second, analyzing the relationship between facilities and population to determine the underdeveloped areas.

The Chinese Ministry of Housing and Urban Rural Development has issued a “Standard for Urban Residential Area Planning and Design” that classifies the facilities in the community life circle into different groups. The Jinan Municipal Government has followed this standard and divided the facilities into six categories. Our research also adopted the same facility classification in this study. Secondly, the number of facilities within each category was determined for each 15 min-CLC using Points of Interest (POI) data. Thirdly, the proximity of each facility category to residential sites was evaluated to gain insights into the variations between the 15 min-CLCs in old and new communities. This analysis provided an understanding of the accessibility and proximity of different types of facilities to the residents. Fourthly, to assess the service capacity of each 15 min-CLC, the ratio of the number of facilities to the population was calculated for each facility category. This ratio can determine the adequacy of services provided within each 15 min-CLC and identify the underdeveloped regions. Finally, based on the findings from the evaluation process, underdeveloped regions and specific facility categories that require improvement can be identified.

A visual representation of the research flow was presented in Figure 1, providing a clear overview of the methodology and the sequential steps involved in the evaluation process.

2.2.1. Study Area

Jinan City is the capital of Shandong Province in China. Jinan City encompasses 10 districts and 2 counties, covering a total area of 10,244.45 square kilometers. According to the 7th national population census, the permanent population of Jinan was 9.2 million by November 2020, and the average annual population growth rate was 1.27% [32].

The implementation of the 15 min-CLC concept was proposed by the Jinan City government in 2016 as part of efforts to achieve balanced development across the entire city. In 2019, Jinan City Planning Bureau issued the “Jinan Planning Guidance of 15 min Community”, providing guidelines for the implementation of the 15 min-CLC concept [33]. In the “Jinan Planning Guidance of 15 min Community”, it is emphasized to develop the new and old communities separately during the implementation of the 15 min-CLC concept. This guidance identified 52 old communities and 68 new communities among the 120 selected communities that implemented the 15 min-CLC concept (Figure 2).

China’s urban community development began in 1990 and went through various stages. The “Opinions on Promoting Urban Community Construction Nationwide” issued in 2000 marked the maturity of China’s urban community system [34]. The communities built before and after 2000 are considered old and new, respectively. They have significant differences in terms of economic activities, environment, and basic infrastructure. The old communities usually have narrow roads and a historical layout. They also have a diverse and dense population, and are located in the city’s commercial and cultural centers. The new communities, on the other hand, have wide roads and a planned layout. They are designed to accommodate the rapid urban growth, and tend to attract more young and transient population [35,36,37]. This phenomenon of new and old communities is common in many Chinese cities [38].

Jinan City’s plan for implementing 15 min-CLCs focuses on seven districts, namely, Gaoxin District, Changqing District, Shizhong District, Huaiyin District, Tianqiao District, Lixia District, and Licheng District [34]. The guideline defines the 15 min-CLCs based on three key aspects. Firstly, the population of 15 min-CLCs is determined by calculating the population density, ranging from 50,000 to 80,000 people. Meanwhile, the residential land area should be between 1.5 and 8 km². Secondly, urban blocks are considered as the basic units of the 15 min-CLCs. Thirdly, the scope of the 15 min-CLCs is delineated based on the areas where various service facilities can be reached within 5 to 15 min. In addition, the guidelines recommend that 15 min-CLC should not be separated by natural features such as large rivers, mountains, or railways and roads.

2.2.2. Data Collection

The data collection process for this research involved gathering information on the various facilities within the 15 min-CLCs as defined in the “Jinan Planning Guidance of 15 min Community” [35]. These facilities were categorized into six distinct categories: (C1) daily service facilities, (C2) administrative service facilities, (C3) medical facilities, (C4) elderly care facilities, (C5) open space, and (C6) educational and cultural facilities, as detailed in

Table 1. Data and sources.

Data Types		Measurements	Sources
Facility Categories	Daily service (C1)	Counting the number of POIs of food markets, maintenance shops, express delivery stations, supermarkets, banks, ATMs, convenience stores, public toilets.	The website of Baidu Map. https://lbs.baidu.com/index.php?title=webapi/guide/webservice-placeapi (accessed on 28 September 2022)
	Administrative service (C2)	Counting the number of POIs of police stations, community service centers, subdistrict offices.
	Medical care (C3)	Counting the number of POIs of hospitals, clinics.
	Elderly care (C4)	Counting the number of POIs of elderly care facilities.
	Education and culture (C5)	Counting the number of POIs of cultural and educational facilities, fitness services.
	Open space (C6)	Counting the number of POIs of parks.
Population		China population census yearbook.	The website of 15. National Bureau of Statistics of China. http://www.stats.gov.cn/tjsj/ndsj/2021/indexeh.htm (accessed on 6 October 2022)

.

C1 (daily service facilities): Daily service facilities are providing sufficient and diversified convenience services nearby to meet the daily needs of shopping, eating, and maintenance in the life cycle. Facilities include vegetable markets, housekeeping service centers, maintenance points, express service shops, small supermarkets, convenience stores, hardware stores, public toilets, and renewable resource recycling stations. C2 (administrative service facilities): Administrative service facilities are strengthening community autonomy, fostering the growth of social organizations, and helping residents find jobs and start businesses. Facilities include street office management, community grassroots offices, social organization incubation, employment guidance, entrepreneurship guidance and skills training, and embedded office space. C3 (medical care facilities): The medical care facilities pay attention to people’s health in the whole life cycle and enrich community medical services. They include community health services, health care for all age groups, tracking of chronic diseases, psychological counseling, and hospice care. C4 (Elderly care facilities): The elderly care facilities are building a flexible, shared, and balanced elderly care system that pays attention to the physical and mental needs of the elderly. Facilities include centralized residential care for the elderly, day care services, elderly education services, and catering services. C5 (Open spaces): Open spaces are providing multi-level and multi-type public activity venues and building space for public activities. Community public open spaces and small public spaces (street gardens, cultural fitness squares, etc.) are examples of facilities. C6 (Educational and cultural facilities): Educational and cultural facilities are providing diversified care and education for juveniles, increase the allocation of public education facilities, and improve the quality of fitness and entertainment activities in the life circle. Facilities include preschool care, early childhood education training centers, adult interest training facilities, and fitness centers.

To determine the number of facilities in each category within the 15 min-CLCs, Point of Interest (POI) data were utilized. POI data contain geospatial coordinates and additional attributes such as names, categories, addresses, and contact information [13,39]. In this research, the POI data were collected from the Baidu Map (https://map.baidu.com (accessed on 28 September 2022)), which is the equivalent of Google Map in China and is widely used for navigation, location-based services and geographic information, providing valuable information about the facilities’ quantity and locations within the 15 min-CLCs (Table 1). Population data for Jinan City were obtained from the 2020 China Statistical Yearbook [32]. These data were utilized to analyze the population distribution within the 15 min-CLCs in Jinan City. Figure 3 illustrates the population distribution of 15 min-CLCs in Jinan City. The population distribution of Jinan is mainly concentrated in Areas 23, 67, 68, 104, 115, and 116 (Figure 3).

2.2.3. Analysis of Facilities Distribution in the Old and New Communities

The distance between the facility and the residence is a crucial factor in assessing convenience [27,40,41,42]. To understand the distribution of facilities within the 15 min-CLCs, it is important to analyze the facilities’ distribution in both the old and new communities separately. This analysis helps to identify the kinds of facilities that require attention and measures the improvement of these facilities.

Logan (2022) employed a method that calculated the walking time from the centroid of each neighborhood block to the nearest amenity [27]. However, for many second-tier cities in China, including Jinan City, neighborhood boundaries may not be clearly defined, rendering Logan’s method unsuitable for our study. Therefore, our research proposed the use of POI data for analysis, as it allows to measure the spatial relationship between each residence and various facilities. Our research estimated the distance from the residential POIs to the POIs of the nearest facilities, to understand the general distribution characteristics of six categories of facilities in Jinan City using the density distribution method.

2.2.4. Evaluation of Facilities Distribution in Each 15 min-CLC

Considering the differences between 15 min-CLCs as mentioned above, it is essential to evaluate the distribution of facilities within each 15 min-CLC to ensure they meet the daily needs of residents. Evaluating the distribution of different facilities in 15 min-CLCs can be helpful to identify areas that may lack adequate facilities. By counting the POIs of each 15 min-CLC and analyzing the distribution characteristics of different facility categories, this research can understand the areas where facilities are distributed unevenly. The number of facilities belonging to each category was used to depict the development situation of each 15 min-CLC.

While it is assumed that the existing facilities can meet the daily needs of residents in the current situation of the 15 min-CLCs, Wu (2021) pointed out the scarcity of previous studies discussing the balance between the demarcation of the 15 min-CLCs and the population demands within the Community Life Cycle (CLC) [31]. Therefore, our research developed a method for analyzing the relationship between facilities and population. We proposed a measurement called the Facility to Population Ratio (FPR), which calculates the number of facilities per thousand people within a 15 min-CLC. This method enables a direct assessment of the balance in facility allocation across different 15 min-CLCs. Additionally, it can provide valuable insights and development directions for 15 min-CLCs that require further attention and development.

Furthermore, this research attempted to calculate the FPR values of new and old communities separately in Jinan City. Since in the process of urban development, the development speeds of different communities vary, and urban expansion will also lead to the emergence of new and old communities [43]. Therefore, the development of existing service facilities in different communities exhibits significant disparities. A comprehensive understanding of the development of basic service facilities in diverse communities is crucial for effectively implementing the 15 min CLC concept.

3. Results and Discussion

3.1. The Distribution of Various Facilities in the Old and New Communities

In previous studies, it was mentioned that a 15 min walking distance was approximately 1000 m [13,30]. Figure 4 illustrates the distribution of each type of facility in Jinan City. In order to show the concentrated distribution of various types of facilities in Jinan City, 2000 m was selected as the maximum observation distance on the x-axis in Figure 4. The results of this research provide insights into the distribution of facilities in Jinan City, obtained by calculating the Euclidean distance between residential POIs and the POIs of six service facilities. The analysis reveals that residents can access educational and cultural services, daily services, and medical services within a 1000 m radius (15 min walking distance) from their residences. However, only 71% of the residences have administrative services within this range, and 90% of the residences have access to open spaces. Elderly care services are available within a 1000-m radius for only 46% of the residences. This disparity is due to previous urban planning practices that situated elderly care facilities in areas far from the urban center, rich in natural landscapes. However, current urban planning considerations prioritize convenience and meeting the daily needs of residents. Therefore, future planning efforts should focus on the further development of administrative services, elderly care services, and open spaces to enhance the implementation of the 15 min-CLC concept in Jinan City.

Furthermore, density distribution analysis was conducted separately for the 15 min-CLCs in new and old communities to understand the differences in facility distribution characteristics. Figure 5 and Figure 6 present the results of this analysis. The findings reveal significant variations in the distribution of elderly care facilities and administrative facilities between the new and old communities in Jinan City. In the 15 min-CLCs of old communities, most service facilities are within a 1000-m radius from residences. However, in the 15 min-CLCs of new communities, the concentration of administrative facilities and elderly care facilities within a 1000-m range is lower. In fact, the average distance between residences and elderly care services exceeds 2000 m. To address this disparity, future development planning should incorporate measures to improve underdeveloped facility types.

Several previous studies have proposed determining the extent of neighborhood boundaries to evaluate facility distribution [27,28,40,44,45,46]. As mentioned above, Jinan City is the only second-tier city that has a comprehensive plan to implement the 15 min-CLC concept, and it has clearly defined the boundaries of each community. This means that the previous research [27,28,40,44,45,46], which depends on the identification of community boundaries, may not be applicable to other second-tier cities that lack such planning. To facilitate a more comprehensive evaluation of facility distribution in urban areas, our research suggested a direct analysis of facility distribution throughout the entire city by calculating distances between different POIs. This methodology, presented in our study, can be applied to a wider range of cities, enabling efficient identification of underdeveloped facility types.

3.2. The Distribution of Facilities in the Each 15 min-CLC

It is necessary to understand the current development situation of facilities within each 15 min-CLC. The number of various facilities within each 15 min-CLC was counted. Figure 7a–f present the current situation of various facilities within 15 min-CLCs.

In Jinan City, the average number of daily service facilities in 15 min-CLCs was 172. The average number of administrative service facilities was 1.5. The average number of medical care facilities was 56. The average number of elderly care facilities was 0.4. The average number of educational and cultural facilities was approximately 80. The average number of open spaces is approximately 7.

Examining the distribution of facilities within the 15 min-CLCs, it was found that 60% of the 15 min-CLCs had administrative services below the average, with 48 out of 120 lacking administrative services entirely. Area 42 and Area 111 have the largest quantity of administrative services in Figure 7b. For educational and cultural services, 69% of 15 min-CLCs have fewer facilities than the average, including four 15 min-CLCs without educational and cultural facilities. Areas 48, 49, 50, 51, 54, 55, and 113 have the highest quantity and are concentrated in the urban center (Figure 7e). In terms of open spaces, 87% of the 15 min-CLCs have fewer open spaces than the average level, with 25 regions lacking any open space. Areas 66, 107, and 115 have the largest number of open spaces in Figure 7f. Approximately 70% of the 15 min-CLCs’ has less than the average elderly care services. In addition, 81 15 min-CLCs do not have elderly care services. Area 3, which is far from the urban center with rich natural scenery, has the highest level of elderly care facilities as in Figure 7d. Moreover, about 74% of the 15 min-CLCs have less than the average number of daily services. Figure 7a shows the distribution of daily services in Jinan City. The medical services were below average in 47% of 15 min-CLCs with five 15 min-CLCs without any medical facility as in Figure 7c. In addition, some well-developed 15 min-CLCs has a higher number of each type of facilities compare to the average, such as Area 45, Area 66, and Area 114. These results highlight the areas where facilities fall below or exceed the average, indicating the different need for further development. Meanwhile, these results provided a basis for the comparison of facilities and population, helping to discuss whether the daily needs of residents can be met.

3.3. The Selection of the Underdeveloped 15 min-CLCs

To ensure the facilities can meet the daily needs of residents while achieving equality of resource allocation among 15 min-CLCs, the number of facilities and the population in each area should be considered. In this research, a “Facility to Population Ratio” (FPR) was proposed to investigate this relationship and identify underdeveloped regions in Jinan City. The development situation and economic strength of different cities vary, making it difficult to evaluate different cities within a fixed value. This research focused on identifying relatively underdeveloped areas within a city. Therefore, the FPR values for each facility category in each 15 min-CLC were calculated, and compared to the citywide average. This method can help identify the areas that need to be developed in local contexts.

Table 2. Results of FPR values in the 15 min-CLCs.

Areas	Daily Service (C1)	Administrative Service (C2)	Medical Care (C3)	Elderly Care (C4)	Education and Culture (C5)	Open Space (C6)
5	1.411	0.000	0.000	0.000	0.000	0.000
13	0.434	0.000	0.193	0.000	0.000	0.000
36	6.591	0.361	2.167	0.000	0.000	0.000
20	5.724	0.000	2.289	0.000	0.000	0.000
77	0.028	0.000	0.028	0.000	0.057	0.000
94	1.170	0.130	0.260	0.000	0.130	0.000
37	6.690	0.000	0.000	0.000	0.291	0.000
76	10.954	0.000	1.730	0.000	0.577	0.000
91	0.331	0.000	0.166	0.000	0.580	0.000
6	0.437	0.000	0.087	0.000	0.700	0.000
96	8.117	0.000	0.406	0.000	0.812	0.000
65	0.513	0.000	0.342	0.000	0.855	0.000
16	0.723	0.000	0.000	0.000	0.964	0.000
79	1.249	0.059	0.416	0.000	1.011	0.000
63	6.903	0.128	3.579	0.000	1.023	0.000
35	6.901	0.000	2.588	0.000	1.078	0.000
11	2.851	0.000	0.143	0.000	1.497	0.000
97	40.302	0.923	13.844	0.615	1.538	0.000
28	10.721	0.133	3.737	0.000	2.491	0.000
86	11.044	0.221	3.534	0.000	4.638	0.000
19	9.854	0.000	3.890	0.000	4.797	0.000
120	12.069	0.000	2.364	0.124	6.595	0.000
89	55.309	0.000	4.707	0.000	7.061	0.000
62	11.389	1.752	0.000	0.000	56.944	0.000
54	35.062	0.859	10.141	0.000	62.906	0.000
58	1.999	0.000	0.629	0.000	0.835	0.019
46	1.155	0.023	0.531	0.023	0.624	0.023
50	3.381	0.000	1.630	0.048	6.665	0.024
49	6.850	0.000	2.691	0.027	7.421	0.027
17	1.830	0.031	0.729	0.016	0.078	0.047
110	1.847	0.016	0.714	0.000	3.119	0.047
72	5.910	0.000	2.010	0.000	1.235	0.048
85	1.769	0.000	0.893	0.000	0.331	0.050
43	4.692	0.000	1.460	0.043	2.693	0.057
56	7.999	0.043	2.645	0.000	3.806	0.065
93	1.866	0.035	0.708	0.000	0.622	0.069
88	2.235	0.210	0.699	0.000	0.279	0.070
104	3.537	0.041	1.029	0.020	1.121	0.071
7	0.441	0.000	0.331	0.000	0.000	0.074
100	8.270	0.098	2.535	0.000	3.643	0.074
105	4.117	0.025	0.864	0.000	4.473	0.076
70	5.889	0.058	2.184	0.039	1.033	0.078
68	2.465	0.045	0.965	0.018	0.741	0.080
15	2.597	0.269	1.120	0.000	0.716	0.090
53	6.367	0.092	2.718	0.015	3.741	0.092
41	3.653	0.015	1.345	0.000	2.934	0.092
116	2.613	0.041	1.086	0.010	0.318	0.092
22	3.379	0.059	1.284	0.000	0.375	0.099
4	5.213	0.000	1.497	0.028	0.028	0.111
111	7.146	0.337	4.415	0.037	4.939	0.112
10	0.988	0.038	0.380	0.000	0.076	0.114
61	10.711	0.077	4.816	0.000	1.657	0.116
83	5.094	0.000	1.932	0.000	3.630	0.117
38	6.106	0.000	1.869	0.000	6.106	0.125
52	12.906	0.254	6.103	0.064	11.444	0.127
3	7.028	0.039	2.002	0.079	0.157	0.137
103	3.713	0.034	2.097	0.034	5.088	0.138
48	5.323	0.000	1.987	0.000	5.530	0.138
109	7.564	0.000	1.909	0.024	5.325	0.141
33	14.154	0.000	3.841	0.071	12.945	0.142
57	29.787	0.036	6.471	0.000	5.929	0.145
101	13.718	0.109	3.711	0.036	7.678	0.146
71	20.999	0.074	3.684	0.000	5.673	0.147
90	2.956	0.000	1.921	0.000	0.443	0.148
78	7.766	0.102	3.451	0.051	2.690	0.152
32	16.286	0.000	5.922	0.000	4.339	0.153
106	6.349	0.104	3.122	0.052	3.513	0.156
67	6.894	0.011	1.893	0.011	1.101	0.161
108	4.536	0.042	0.936	0.021	1.789	0.166
113	8.052	0.050	2.001	0.000	5.506	0.182
60	12.838	0.183	4.768	0.000	6.052	0.183
118	2.753	0.138	0.872	0.000	1.239	0.184
75	10.883	0.093	5.116	0.000	3.721	0.186
18	3.205	0.000	2.828	0.000	1.885	0.189
95	0.756	0.000	0.284	0.000	0.095	0.189
81	4.890	0.064	1.207	0.000	1.080	0.191
69	7.881	0.194	1.486	0.000	4.716	0.194
44	6.814	0.081	2.379	0.000	4.234	0.202
80	11.546	0.041	3.374	0.000	0.935	0.203
23	2.131	0.029	1.012	0.010	2.092	0.206
45	7.276	0.044	2.263	0.015	3.342	0.207
24	9.638	0.072	4.028	0.000	9.422	0.216
39	6.189	0.028	0.700	0.028	1.008	0.224
114	7.787	0.064	3.532	0.032	2.986	0.241
59	13.791	0.127	4.049	0.000	1.771	0.253
26	20.221	0.317	5.008	0.000	7.987	0.254
21	1.357	0.000	0.452	0.000	0.090	0.271
25	4.312	0.125	1.437	0.000	3.687	0.312
82	13.649	0.000	2.383	0.000	2.492	0.325
84	6.489	0.127	2.418	0.000	4.454	0.382
117	6.022	0.000	2.603	0.000	4.644	0.408
40	11.824	0.102	3.422	0.000	1.634	0.485
73	33.398	0.000	9.763	0.000	7.707	0.514
98	40.355	0.273	10.907	0.000	11.725	0.545
74	2.456	0.000	0.000	0.000	7.367	0.614
64	1.950	0.000	1.300	0.000	3.900	0.650
34	0.000	0.000	0.667	0.000	2.669	0.667
27	34.591	0.591	16.064	0.099	7.194	0.690
29	45.504	0.000	18.377	0.000	51.630	0.875
31	12.015	0.000	1.886	0.000	3.070	0.877
51	32.367	0.193	7.633	0.000	27.053	0.966
42	5.188	0.371	3.104	0.093	4.772	1.019
2	38.965	0.354	14.169	0.000	17.357	1.063
115	3.888	0.022	1.955	0.022	0.270	1.146
99	28.760	0.000	5.177	0.000	3.451	1.150
30	60.460	0.000	20.645	0.000	16.811	1.180
55	20.327	0.150	8.266	0.000	12.775	1.202
9	0.638	0.000	0.080	0.000	0.319	1.382
107	5.466	0.019	0.856	0.019	3.910	1.556
87	13.700	0.266	5.586	0.000	4.921	1.596
47	22.659	0.000	7.324	0.000	5.607	1.602
66	8.386	0.026	1.585	0.013	2.390	1.611
102	7.905	0.000	5.043	0.000	18.808	1.908
112	73.548	0.000	19.107	0.523	54.703	2.094
Mean	10.524	0.097	3.232	0.021	5.587	0.307

shows the results, with gray shadowed numbers indicating FPR values lower than the citywide averages and red numbers indicating no facilities in that category within the area.

In Jinan City, only Area 27 was the most developed area, with all FPR values greater than the average values of Jinan City. Seven regions had only lower than average FPR values, which means that a certain facility in these regions is insufficient relative to the population. All six categories of facilities in most 15 min-CLCs are inadequate in Jinan City. A total of 79 regions have lower than average FPR values for daily services, 83 regions have lower than average FPR values for administrative services, 77 regions have lower than average FPR values for medical care, 90 regions have lower than average FPR values for elderly care services, 87 regions have lower than average FPR values for educational and cultural facilities, and 87 regions have lower than average FPR values for open spaces.

The results of this research quantified the phenomena that occur in the development process of second-tier cities. The existing economic foundation has attracted more and more people to settle in these cities, but the existing facilities are not sufficient to meet the growing daily needs. Unlike the situation in first-tier cities where inadequate facilities result from uneven resource distribution, second-tier cities experience a different scenario [47]. In these second-tier cities, the phenomenon of insufficient facilities for residents within densely populated areas arises due to rapid urban expansion surpassing the capacity for infrastructure development and service provision [11]. Meanwhile, other second-tier cities can calculate the FPR values to understand the areas that cannot meet the daily needs of residents and the number of facilities required as well.

Based on the FPR values of each 15 min-CLC, some measures can be taken to prioritize the development of regions with lower FPR values. According to the previous research, optimizing the 15 min-CLC concept can involve various approaches. Compact developments can be considered in locations with limited developable land, while shared facilities can be built in adjacent areas to reduce land occupation [13]. Function sharing among facilities can also enhance the overall development of 15 min-CLCs and accommodate the diverse daily life habits of different age groups [31]. In summary, the analysis of FPR values and facility distribution highlights the need for further development of facilities in underdeveloped 15 min-CLCs. By adopting specific strategies and considering the unique characteristics of each 15 min-CLC, second-tier cities, including Jinan City, can effectively implement its 15 min-CLC concept and provide residents with improved living environments.

4. Conclusions

The 15 min Community Life Circle (15 min-CLC) is a concept that proposes to create livable and attractive urban spaces for residents. It suggests that people should be able to access essential services, such as education, health care, leisure, and transportation, within a 15 min walk or bike ride from their homes. The 15 min-CLC concept also encourages the provision of basic services and the improvement of the urban environment to enhance residents’ well-being and satisfaction. This concept has been adopted by many countries around the world, including China, where it has been applied in some of the largest cities, such as Beijing and Shanghai. However, there is a lack of research on how the 15 min-CLC concept can be implemented in second-tier cities, which have a large population and a strong economy, but also face challenges such as inadequate urban infrastructure and uneven development between new and old communities. This study aimed to identify the underdeveloped areas and facilities, taking Jinan City as a case study of a second-tier city.

This research examined how six categories of service facilities that are important for daily living are distributed and developed within the 15 min-CLCs, based on the Jinan Planning Guidelines for 15 min Communities. Our research evaluated these facilities in both old and new communities to find out the underdeveloped facilities which need more planning in the future. The results showed that old communities have all kinds of service facilities within a 15 min walk (1000 m). However, in new communities, there is a lack of administrative services and elderly care facilities. We also counted the POIs for each facility category in each 15 min-CLC to obtain an overview of the facility development situation and observed variations among the 15 min-CLCs. It was found that only a few 15 min-CLCs had relatively complete facility development.

To provide a measure of the service capacity of each 15 min-CLC, we used the “Facility to Population Ratio” (FPR), which compared the number of facilities and the population. This method could help people to identify the underdeveloped areas. For instance, the results indicated that many 15 min-CLCs have lower FPR values, meaning that the daily needs of residents in these areas are not satisfied, even in old communities in the city center. This is a typical feature of second-tier cities, where economic growth attracts many people to migrate, and the existing facilities cannot cope with the rising daily demands. Additionally, the FPR values helped to evaluate the development of different facilities in each 15 min-CLC. For example, people could figure out which types of facilities were lacking or insufficient in each 15 min-CLC.

This research identified the underdeveloped areas and facilities by analyzing the facility distribution and assessing the relationship between the facilities and population, thereby contributing to the development of 15 min-CLC concept in second-tier cities. The findings provided some insights for urban planners and policymakers to improve the quality of life and find the development direction of each 15 min-CLC.

However, it is important to acknowledge the limitations of this research. The POIs used to measure the availability of facilities do not reflect the actual service capacity of each facility, which could affect the accuracy of the results. A possible improvement for future research is to use weighting factors to account for the service capacity of different facilities. In addition, the methodology proposed in this study can be applied to other urban and rural contexts, allowing for wider applications and comparisons.