With the continuous acceleration of urbanization, children have become an important part of urban construction. To create an environment suitable for children's healthy growth, local governments across the country have been actively carrying out the construction of child-friendly cities. This article will start from the background, goals and current situation of child-friendly city construction, analyze typical cases in this field, and look forward to the future development direction

Abstract: Meeting the diverse travel needs of children and parents and building safe, comfortable and interesting street Spaces for children is not only a concrete manifestation of humanistic care for the children group, but also a basic requirement for urban stock renewal, quality improvement and efficiency enhancement. Starting from the aspects of safety, comfort and fun, a child-friendly investigation and assessment of the road space along both banks of the South Changhe River in Zizhuyuan Sub-district, Beijing was conducted by using various methods such as research interviews and GIS analysis. Based on this, the design of a child-friendly street space renovation plan is carried out, including optimizing the street cross-section, comprehensively utilizing opportunistic land, installing child-friendly street facilities, and conducting an integrated design both inside and outside the road red line, etc. Finally, a design framework for child-friendly street Spaces is further proposed, providing technical methods for the renovation of street Spaces in different cities.
Key words: Urban transportation Child-friendly city Traffic safety Street design Beijing

Introduction
In 1996, UNICEF and the United Nations Human Settlements Programme jointly launched the "Child-Friendly Cities" initiative, and the construction of child-friendly urban environments has gradually become a key focus in planning and construction [1]. Studies have shown that non-motorized transportation activities such as walking and cycling outdoors are important sources of physical activity for children [2]. Daily school walks are often one of the best forms of exercise for children [3]. Activities in urban environments are also of great significance to the social and intellectual development of children [4].
Children's activity range is very wide, covering every street and alley in the city. The urban street space has become an important space for children's activities. The venues for children's high-frequency and long-duration activities are not the green Spaces in residential areas or parks, but the sidewalks on both sides of the roads and the open Spaces on the streets [5]. However, the congested, noisy and interwoven street Spaces of people and vehicles often pose numerous safety hazards, and children's activities in urban environments are increasingly restricted. In recent years, the proportion of Chinese children walking or cycling to school has shown a downward trend. Take Beijing as an example. The proportion of school-age children traveling to school by motorized vehicles has increased [6]. The pick-up and drop-off personnel and vehicles have exacerbated the congestion around schools, posing hidden dangers to children's non-motorized transportation and creating a vicious cycle.

Given the significance of children's activities and the importance of streets to children's activities, it is necessary to re-examine the current street space from a child-friendly perspective and put forward new requirements for street renewal and transformation. On the one hand, traffic safety issues have become a significant factor hindering children's non-motorized transportation [7], and the safety of street space is of vital importance to children's activities; On the other hand, comfortable street Spaces provide a good environment for children's community activities [8]. Incorporating elements that attract children into street Spaces to enhance their interest is more conducive to strengthening children's sense of identity and belonging to the street Spaces [9]. Therefore, child-friendly streets should aim for safe, comfortable and interesting streets.
There have been relatively mature exploration experiences in the renovation of child-friendly streets abroad. As early as 1979, Denmark launched a pilot program for pedestrian and cycling traffic safety, setting up a road network system independent of motor vehicles for bicycles and pedestrians [10] At the end of the 20th century, countries such as Australia and Canada also began to advocate promoting children's non-motorized travel through education, encouragement and compulsory measures, and carried out projects such as street renewal design and the creation of shared pedestrian streets [11]. There are relatively few practical explorations on the renovation of child-friendly streets in domestic cities. Most existing academic studies offer suggestions from the perspectives of social governance and public policy [12-13], while others focus on spatial assessment. A typical case is the child-friendliness assessment of public Spaces in Shuangjing Sub-district, Chaoyang District, Beijing [14]. There are relatively few cases of street space renovation in existing studies, and none of them have well proposed specific strategies for renovation design. It is necessary to explore a child-friendly street space design framework.
This article focuses on the design framework of child-friendly street Spaces, paying attention to the characteristics of children's activities. It conducts research and analysis and evaluation of street Spaces from three dimensions: safety, comfort, and fun. Based on this, it further explores the design, with the aim of creating a happier time for children and parents to go to and from school and a richer street life. At the same time, it provides a framework reference for the design and renovation of more child-friendly streets.

1. Research scope and design scope

This article selects the Changwa area in Zizhuyuan Sub-district, Haidian District, Beijing as the research scope. This area is located in the central urban area of Beijing, stretching from Changchun Bridge Road in the north to Zizhuyuan Road in the south, from Landianchang South Road in the west to West Third Ring North Road in the east, with a total area of 1.9 square kilometers. The Nan Changhe River runs through the study area (see Figure 1). The residential density within the research area is relatively high, educational resources are concentrated, and there are several primary and secondary schools distributed. Children have a large demand for travel, and there is a significant demand for child-friendly street Spaces.
Using ArcGIS software, a buffer zone with a radius of 1.5 km was delineated with Haidian Experimental Primary School as the center. A comprehensive analysis of the traffic service level within the study range was conducted. The calculated road network density was 2.8 km·km-2, which was relatively low. The traffic volume was mainly concentrated on two north-south branch roads (Changwa Middle Road and Chedaogou East Road). In addition, most of the bus stops within the study scope are located on the outer urban expressways and main roads. Schools such as Haidian Experimental Primary School, Beijing Institute of Technology Affiliated High School (hereinafter referred to as "BIT Affiliated High School"), and Beijing Institute of Technology Affiliated Primary School (hereinafter referred to as "BIT Affiliated Primary School") have not been fully covered by the 300-meter service range of the bus stops. There are no bus routes passing through Chedaogou East Road, Banbi Street and Changwa West Street, and the overall service level of public transportation is relatively low (see Figure 2).
Based on this, the design scope of this paper is determined to be the area along the design range of Changwa Middle Road (from Changwa Street to Banbi Street section) and Chedaogou East Road (the entire section), with a total length of approximately 830 meters for vehicle travel roads (see Figure 1). This area is home to three primary and secondary schools, and children have a high demand for travel. However, due to poor public transportation accessibility and low regional road network density, a large number of cycling, walking and motor vehicle trips are concentrated within the limited road space. There is an urgent need to reallocate street space resources to facilitate the realization of child-friendly streets and public Spaces.

2. Child-friendliness survey and assessment
2.1 Characteristics of Children's Activities
2.1.1 Spatiotemporal Characteristics
The spatio-temporal characteristics of children's activities are largely influenced by the location of primary and secondary schools and their time periods for going to and from school. As the morning school start time is concentrated around 7:00, there is no phenomenon of parents parking for a long time to wait. Moreover, children have a tight schedule on their way to school and rarely stop by the roadside to play. Therefore, this article will focus the observation of children's activities on the after-school period.
The basic information of the three primary and secondary schools is as follows: 1) Haidian Experimental Primary School, located on the north bank of the river, has approximately 1,700 students and ends school at 16:00 every afternoon. 2) The High School Department of the High School Affiliated to Beijing Institute of Technology is located on the south bank of the river. The first and second years of high school finish at 17:00, and the third year at 21:30. 3) Beijing Institute of Technology Affiliated Primary School has approximately 1,300 students. Regular classes end at 15:20, while after-school care classes end at 16:20. On-site research found that during the dismissal time (16:00-17:00 on weekdays), parents who have been waiting for a long time and a large number of students pouring out of the school often prevent motor vehicles from passing on both sides of the school gate, causing local traffic paralysis on Changwa Middle Road and Chedaogou East Road. It can be seen from this that the children's activities within the study scope are mainly distributed in the afternoon after school in terms of time and in the sections in front of the school gates of three primary and secondary schools in terms of space, presenting a highly concentrated feature in both time and space.
2.1.2 Behavioral Characteristics
From 15:00 to 17:00 on Thursday, December 17, 2020, starting from the entrances of the Affiliated primary School of Beijing Institute of Technology and Haidian Experimental Primary School, the activity trajectories of children under 15 years old who traveled alone or in groups (including those accompanied by parents) after school were tracked until the boundaries of the study range. Their activity points and stopover points were recorded, and ultimately 212 activity trajectories were obtained.
The activity trajectories were input into ArcGIS to conduct a density analysis of children's activity paths within the study scope (see Figure 3a). The results show that the area with the most concentrated activity paths is located on the section between the school gate and the intersection closest to the school gate. The destinations of the paths on both sides of the river are all concentrated at the bus stops on the urban expressways and main roads. During the research, it was also observed that the walking speed of children on the section between the Affiliated High School of the Institute of Technology and the Affiliated Primary School of the Beijing Institute of Technology was significantly lower than that on other sections. There are two possible reasons:
A large number of students from the junior high school department of the High School Affiliated to Beijing Institute of Technology (located outside the research area, on the east side of the North Third Ring Road west) arrive at the senior high school department for extracurricular activities after school every afternoon. Most of these children walk with their friends and tend to chat during the walk
Even during the day, there are often playful and fussy movements, which leads to a slower walking speed. 2) Children often stop at a small shop on this section of the road. The shop is located in a shabby bungalow and doesn't even have a formal sign, yet it still attracts a large number of passing junior high school students. The duration of their stay varies from 1 to 5 minutes.
The stopover points were entered into ArcGIS for kernel density analysis (see Figure 3b). By comparing with the real street photos, it can be seen that students' stopover activities are mainly concentrated in three places: 1) The area in front of the school gate. The chaotic gathering of a large number of parents and the narrow street space cause traffic paralysis. After leaving school, children often need 1 to 2 minutes to completely leave the section in front of the school gate. 2) At intersections with heavy traffic, parents and children wait here due to the need to cross the street. 3) Sites with undulating features, such as the sections with the densest stops on the north bank, are equipped with stepped seats and retaining slopes that rise above the ground. The undulations and height differences stimulate children's interest in activities, making them more inclined to walk on them. 4) Shopping places that are attractive to children, such as the small stores mentioned above.

2.2 The Demand for street space in children's activities
1) Streets should be as wide and comfortable as possible, providing separate activity Spaces from motor vehicles and non-motor vehicles. Children's activities show obvious randomness and uncertainty. Children like to travel in groups and even chase and play on the streets.
2) Interesting landscape elements (such as tree pits, flowers and grass, etc.) and non-landscape elements (such as height differences, curbs, markings, etc.). Children have a strong desire to play and are highly sensitive to spatial resources. Any available spatial resources (such as plants, playground equipment, height differences, etc.) can attract children to leave the set route or even stay. [15]
.
3) Children of different age groups have varying demands for street space. Primary and junior high school students exhibit distinct activity characteristics. The former prefer playing games, running and staying, while the latter are more inclined towards socializing and chasing and playing around. It is necessary to set up different play Spaces for children of different age groups.
4) Parents and children have different demands for street space. Children pay more attention to the fun of the streets, while parents are more concerned about the safety and comfort of the streets. Safe street Spaces provide a guarantee for parent-child outings, while comfortable street Spaces offer more facilities for parents to rest and wait, making it more likely for parents to allow children to play in the street Spaces. Therefore, the renovation of child-friendly streets also needs to take into account the usage needs of parents.
2.3 Evaluation of Child-friendly Street Spaces Based on the spatio-temporal characteristics, behavioral features of children's activities and their demands for street Spaces, this paper further analyzes the current street Spaces within the research scope from the supply perspective and conducts a child-friendly assessment from the perspectives of safety, comfort and fun.
From the perspective of safety, the poor accessibility of public transportation leads residents to rely more on private cars for travel. The low density of the road network causes a large number of vehicles to mix in the limited street space, posing a significant safety hazard to children (see Figure 4a). The main factors affecting street safety include: 1) Narrow sidewalks, with the width of a single sidewalk on some streets being less than 1.5 meters; 2) Random parking on the street occupies street space. There is a lack of public parking lots within the plot that are open to the outside. The phenomenon of disorderly parking is particularly serious during the after-school hours. 3) Due to the fact that the building setback line cannot meet the requirements of the viewing distance triangle, there are many blind spots at the intersection. 4) There is a lack of pedestrian crossing facilities, such as zebra crossings and clear intersection stop markings. The above-mentioned potential dangers are mainly concentrated on Chedaogou East Road and Changwa Middle Road.
From the perspective of comfort, the areas around Nanchanghe Park and the renovated section of Haidian Experimental Primary School are relatively comfortable. The former has an open greenway along the river, while the latter, in combination with the community micro-update project, has standardized motor vehicle parking Spaces and arranged waiting areas for parents (see Figure 4b). The northern section of Changwa Middle Road and the southern section of Chedaogou East Road are less comfortable. The main reasons are the leakage of kitchen waste from street-facing merchants, the accumulation of construction waste, an excessive number of shared bikes, the occupation of pedestrian space along the street, and the inconvenience of using some street furniture. At the same time, there are no rest and waiting facilities set up at the school gate of the Affiliated primary school of BIT, which brings inconvenience to parents picking up and dropping off their children.
From the perspective of fun, the distribution of children's entertainment facilities and activity Spaces within the plot is uneven. They are mainly concentrated in the renovated sections of Haidian Experimental Primary School and Nanchanghe Park, and have not been designed specifically based on the differences in the activity characteristics of children of different age groups. There are basically no street fun Spaces on other sections of the road. There are few space resources for children to explore and play. There is a lack of venues with undulating features and attractive shopping and leisure places. There are almost no play facilities and ground pavements specially designed for children. The probability of children staying is relatively low (see Figure 4c).
In conclusion, problems such as random parking on both sides of the road, garbage piling up, and the occupation of pedestrian space have become the main factors affecting the safety, comfort and interest of the street. The overall street environment urgently needs to be improved. Due to the varying demands of different age groups for open street Spaces, it is difficult to achieve absolute safety, comfort and interest in the optimization and renovation plan. This article, from a child-friendly perspective, focuses on the activity needs of children and proposes design strategies for relatively optimized street environments.

3. Child-friendly street design methods
This article takes the design of child-friendly streets as the overall starting point, designs the renewal and transformation plan for street space, and proposes corresponding solutions to problems such as too narrow road cross-sections, mixed traffic of motor vehicles and non-motor vehicles, parking occupying road space, lack of parents' waiting areas and children's activity facilities within the design scope. Seek two opportunity sites for functional replacement to enhance the safety, comfort and interest of the street environment, and better meet the travel and activity needs of children.
3.1 Street Function Optimization and Cross-sectional Design
Firstly, functional optimization was carried out for the existing roads. Four road functions were redefined from a child-friendly perspective, and the road cross-sections were designed respectively (see Figure 5).

1) Two-way carriageway.
The sections of Changwa Middle Road and Chedaogou East Road with relatively concentrated traffic flow and serving as the connection between internal and external traffic will be designated as two-way carriageways, with a focus on enhancing the safety of the street space. The separation of motor vehicles from non-motor vehicles is achieved by setting up isolation posts and distinguishing the colors of the pavement. Concentrate the on-street parking demand on two opportunity sites and return more street space to children. There are relatively wide sidewalks on both sides of the road for children to commute to school.
2) One-way carriageway.
The demand for motor vehicle traffic on Chedaogou East Road is relatively low, the width of the road red line is narrow, and there is currently no return parking lot at the end. This design focuses on the opportunity land on the south side, transforming the east road of the vehicle channel into a one-way counterclockwise carriageway. It emphasizes enhancing the safety of the street space, achieving the separation of motor vehicles and non-motor vehicles, and ensuring the safety of children's travel.
3) Passable walkways.
The branch road in front of Haidian Experimental Primary School (currently impassable) will be transformed into a passable pedestrian walkway, with a focus on enhancing the comfort of the street space. The road mainly consists of continuous and accessible pedestrian paths. Tree pits are set up in the middle of the road, and non-motorized vehicle lanes are respectively set up on both sides of the road. The road surface elevation is unified. Build a pedestrian bridge across the river to connect with the pedestrian path on the south bank, to meet the pedestrian traffic needs across the South River and facilitate children's access to the South River Park on the south side for play.
4) Active walkway.
The current section on the north side of Chedaogou East Road (the section in front of the school gate of the Affiliated High School of Beijing Institute of Technology) has a relatively low demand for motor vehicle traffic and a high demand for children's walking. The design aims to transform this section into an active pedestrian path, with a focus on enhancing the interest of the street space. A parent-child walkway is set up in the middle of the road. The children's activity area and the non-motorized vehicle lane are respectively located on both sides of the walkway to prevent non-motorized vehicles from posing safety hazards to children playing alone.
3.2 Comprehensive Utilization of Opportunistic Land
There are two potential sites on both the north and south banks of the Nan Changhe River, with areas of 0.61×104 square meters and 0.52×104 square meters respectively. The current status of these sites is an abandoned factory and an idle vacant land. The design involves their renovation and functional implantation (see Figure 6). According to the research
Children have a preference for staying in stores and recreational venues and have certain demands for street playgrounds. Based on this, commercial service functions will be implanted in two opportunity sites, including "small dining tables" (commercial facilities that address children's lunch and rest needs)
The functional modules such as households, retail stores, children's cultural and educational centers, and art training are mainly small-scale buildings.
The activity characteristics of children of different age groups show differences: From 0 to 6 years old, children are active under adult supervision, like to imitate and experience, and have relatively scattered attention. Between the ages of 6 and 12, children move around independently within the adult's line of sight and gradually become competitive
"Strive for awareness;" Children aged 12 to 18 can engage in independent activities and focus on cultural and recreational activities [16].
This article takes into account the age characteristics of children within the site in the design of the internal space of the opportunity site. The activity areas are distinguished by the color of the paved ground, and different types of game facilities are designed to meet the activity needs of children aged 0 to 18. Children aged 0 to 6 can use ordinary play facilities (such as sandpits, fountains, ponds, etc.) and play facilities formed by height differences (such as slides, fortresses). Children aged 6 to 12 can use the participatory venue design facilities (graffiti painting walls). Children aged 12 to 18 can use the game facilities formed by interactive landscape installations. In addition, a leisure area should be set up beside the game venue for parents to wait and rest.
The plan improves the parking problem by transferring on-street parking to the site of the opportunity. There is currently one on-street marked parking area within the design scope. All other areas are illegal on-street parking. The current parking demand is approximately 150. At the same time, considering the problems such as some parents picking up and dropping off their children having no place to park and the tight parking resources in some communities around the design area, 250 motor vehicle parking Spaces are planned. The total area of the two underground parking lots at the opportunity sites is approximately 10,000 square meters, which can effectively meet the parking demands on Changwa Middle Road and Chedaogou East Road within the design scope.
3.3 Child-friendly street facilities
In addition to adjusting the street cross-section and revitalizing the opportunity land, the design also sets up several child-friendly street facilities within the road red line, providing a better street environment for children's travel and activities at the micro scale (see Figure 7). In terms of enhancing safety, anti-slip pavement is installed on the pedestrian paths of all four types of roads to reduce the probability of children falling due to jumping, playing, chasing and fighting. Child-friendly crossing facilities should be designed at the intersections of pedestrian streets and ordinary roads (respectively located on the north side of the school gate of Haidian Experimental Primary School and the south side of the school gate of Beijing Institute of Technology Affiliated High School), including three-dimensional zebra crossings, red stop lines for motor vehicles, and prominent signs, etc.
In terms of improving comfort, round tables, sun umbrellas and other movable street furniture were placed in the two opportunity sites to provide a rest and waiting space for parents waiting for their children to finish school. The sexual walkway and the active walkway are connected across the river by a pedestrian bridge, forming a continuous and smooth parent-child walkway, which improves the travel environment for parents and children.
In terms of enhancing the fun, street game paving and game facilities are introduced in the children's activity area within the active walkway. Parents can pass through the walkway or wait in the waiting pavilion within the activity area, while children can jump and play between the colorful paving and the game markings. In the actual renovation process, public participation methods can also be adopted, allowing children to describe their ideal street fun Spaces in the form of paintings, and the arrangement of street fun facilities can be fully based on children's needs.
3.4 Integrated design both inside and outside the road red line
Make full use of the concave Spaces along the street outside the road red line to extend the street space. Based on the principle of sharing, win-win and co-construction between children and residents, carry out integrated design both inside and outside the road red line (see Figure 8). 1) Sharing: The concave Spaces along the street are available for children to use during their pick-up and drop-off periods, and for community residents to use at other times. 2) Win-win situation: Children gain a safer and more interesting travel environment and activity venues, while residents enjoy environmental improvement and commercial benefits. 3) Co-construction: Introduce public participation measures in practice, collect design opinions from both children and residents, and jointly participate in the design and construction.
The specific strategies include three aspects: 1) Functional replacement, which involves concentrating the functions that are concentrated on the roadside and pose obstacles and disturbances to children's activities to be replaced in concave Spaces and opportunistic land, such as transferring on-street parking to opportunistic land; 2) Asset utilization: In combination with the renovation of old residential areas, optimize the functions of community public buildings and provide more functions for children's use, such as playground equipment and sports facilities for children. 3) Integrated design, breaking the restrictions of the road red line boundary, laying out recreational facilities and parents' waiting facilities, and conducting an integrated design of the site and the street. During the actual renovation process, it can also encourage public buildings along the street to open up the ground floor setback space, or implant children's service functions in the surrounding idle buildings.

4. Child-friendly street design framework
Based on the research and design experience of this paper, a child-friendly street design framework has been initially formed, covering feature judgment, demand analysis, resource sorting, and renovation design.
1) Judgment of traffic characteristics and analysis of children's travel needs.
Judge the basic characteristics such as road network density, public transportation service level, parking infrastructure, and street space quality within the research scope, analyze traffic demand, identify traffic conflicts, and combine interviews and on-site investigations to obtain the spatio-temporal and behavioral characteristics of children's travel within the research scope, and determine the demand for street space in children's activities. Thus, the key design contents are determined in combination with the current traffic pain points.

2) Evaluation of child-friendly street Spaces.
From the perspectives of safety, comfort and fun, the current street space is evaluated to identify sections that urgently need improvement in all aspects, and the specific reasons are analyzed in combination with on-site research.
3) Sorting out and exploring existing resources.
Under the background of highly scarce urban land, it is necessary to fully explore the inefficient land within and outside the design scope, recycle and reuse fragmented and scattered Spaces, and negotiate with relevant property rights units. Through measures such as functional replacement and floor area ratio rewards, encourage the opening of the ground floor space of public buildings along the street, or transfer part of the public space along the street for the transformation of child-friendly street Spaces.
4) Road function division and cross-sectional design.
According to the traffic demands of each section and the actual renovation conditions, roads of different functional types are classified and cross-sectional optimization designs are carried out. The traffic priority of roads should be clearly defined as pedestrians, non-motorized vehicles, and motor vehicles in sequence. When conditions permit, physical isolation between sidewalks, non-motorized vehicle lanes and motor vehicle lanes can be achieved by means of height differences or guardrails. When conditions do not permit, distinctions should be made as much as possible in the pavement. In places where children are frequently active (such as the road section in front of the school gate), measures of reducing or eliminating vehicles should be adopted to ensure the safety of children and parents' travel. For schools that operate school buses, designated drop-off areas for school buses should be set up on both sides of the school gate, and vehicles should be restricted or prohibited from entering these drop-off areas during the rush hours of school pick-up and drop-off.
5) Install child-friendly street facilities.
In terms of enhancing safety, anti-slip paving should be adopted in play areas and regions where children are likely to run around. Optimize the street sign system to remind road users of the existence of children's travel paths with eye-catching and clear patterns. In terms of improving comfort, efforts should be made to increase the green visibility of streets, provide convenient and comfortable street furniture, enhance the interaction between facilities and children at a low ground level, and at the same time offer facilities for parents to wait and rest.
In terms of enhancing the fun, game paving and marking can be set up in the children's activity area, and the game area can be set up in combination with the artificial height difference of the site.

5. Conclusion
From the perspective of child-friendly street space design, this article conducts a research and analysis on the child-friendliness of the Nan Changhe area on both sides of Zizhuyuan Sub-district in Beijing based on three aspects: safety, comfort and fun. It innovatively explores the design of child-friendly streets, summarizes the experience and proposes a design framework for child-friendly streets. And particular attention was paid to the characteristics and needs of children's activities. The proposed renovation plan and design framework comprehensively take into account multiple factors such as transportation supply, travel demand, and community co-governance. In the actual renovation process, it is important to pay attention to grasping the travel needs of children, fully explore the opportunity land, and combine the optimization of road functions and the layout of street furniture to create safe, comfortable and interesting streets that are friendly to children.

I. Background
In recent years, the global urban population has grown rapidly and the urbanization process has been accelerating continuously. According to statistics, more than half of the world's population already lives in urban areas. In cities, children, as a special type of body, often encounter various problems. Problems such as urban traffic congestion, air pollution and insufficient space for children's activities are becoming increasingly prominent, seriously affecting children's healthy growth. Building child-friendly cities has become a major issue that governments of all countries and city governments urgently need to solve.

Ii. Objectives
The main goal of building a child-friendly city is to create a safe, healthy and happy growth environment for children. Specifically, it includes the following aspects:
1. Protection of children's rights: Ensure that children's basic rights are guaranteed, including the right to education, the right to survival, the right to development, etc.
2. Safe living environment: Provide a safe living environment and play areas to ensure the personal safety of children;
3. Healthy Lifestyle: Promote children's healthy growth, advocate a healthy lifestyle, and enhance children's physical and mental health;
4. Participation in social activities: Encourage children to participate in social activities and provide corresponding support and protection.

Iii. Current Situation
At present, the construction of child-friendly cities is gradually being carried out worldwide and has achieved certain results. Here, we have selected several typical cases from countries and regions to better understand the current situation and development direction of this field.

Oslo, Norway
Oslo, Norway, is the world's first child-friendly city to be certified by UNICEF. The city has fully taken into account the needs and rights of children in its urban planning and design, establishing a large number of outdoor playgrounds and green Spaces to provide children with sufficient space for outdoor activities. Oslo has also carried out a series of publicity and education activities on children's safety and health, enhancing society's awareness of children's growth.

2. Tokyo, Japan
As one of the largest cities in Asia, Tokyo has also achieved certain results in the construction of a child-friendly city. Tokyo has effectively enhanced the safety of children's travel by planning its urban transportation system and building dedicated traffic safety facilities for children. Tokyo has also established a large number of children's activity centers and libraries, providing children with a rich variety of social activity opportunities.

3. Shenzhen, China
As one of the economically developed cities in China, Shenzhen has also devoted a great deal of effort to the construction of a child-friendly city. Shenzhen has improved the shortage of children's activity space by planning and constructing a large number of children's parks and youth activity centers. Shenzhen also advocates the concept of "children first", incorporating children's rights and interests into one of the important considerations in urban planning.

Iv. Outlook
In the future, with the continuous advancement of urbanization, the construction of child-friendly cities will encounter more opportunities and challenges. In future work, we should pay more attention to the protection of children's rights and interests and establish and improve a child protection mechanism. Increase investment in the construction of children's activity venues, improve the efficiency of urban space utilization, and provide more activity Spaces for children. Strengthen the publicity and education on children's healthy growth, and guide children to grow up healthily and happily.

Conclusion
As a special skirt body, the healthy growth of children is related to the future of the country and the hope of the nation. Building a child-friendly city is an important social undertaking that requires the joint efforts of the entire society. It is hoped that governments of all countries and city governments can pay more attention to the work in this field and create a better growth environment for children. In the future construction of child-friendly cities, apart from increasing investment in safeguarding children's rights and interests and building children's activity venues, it is also necessary to pay attention to children's needs in urban transportation, education and social participation. A child-friendly urban transportation system should be established. The safety and convenience of children's travel in cities are important aspects of building child-friendly cities. Urban planners need to take into account children's commuting needs and give priority to their travel safety in urban transportation planning. In traffic planning, special pedestrian crossings and traffic lights for children can be added, and safe and convenient school buses or special transportation vehicles for children can be planned and constructed to ensure the safety and convenience of children's travel.

In terms of education, cities should establish a complete education system, provide high-quality educational resources and environments, and enable children to receive comprehensive education. Cities should also offer children a wide range of extracurricular activities and community education programs, encourage them to participate in the cultivation of various interests and comprehensive qualities, and promote their all-round personal development.

Cities also need to advocate and establish opportunities and platforms for children to participate in social activities. Integrate children into the community, urban planning and decision-making processes, enabling them to actively participate in social activities, understand and perceive society, and express their voices. Cultivate children's sense of social responsibility and citizenship from an early age, as well as their sense of participation and innovative spirit. Such measures can not only enhance children's social participation, but also benefit their personal growth and future development.

In the future development, in addition to strengthening various specific tasks, it is also necessary to enhance the formulation and implementation of relevant policies and regulations. Government departments should introduce more specific and forceful regulations and policies, clarify the division of responsibilities, and ensure the smooth progress of the construction of child-friendly cities. It is also necessary to establish relevant indicators and assessment systems to conduct regular evaluations and supervision of the construction of child-friendly cities, and promptly identify and solve problems.

In addition to the government's promotion, all sectors of society should also actively participate in the construction of child-friendly cities. All links, including schools, communities, families and enterprises, should actively cooperate to jointly create a favorable environment for children's healthy growth. At the community level, institutions such as children's activity centers and youth clubs can be established to provide beneficial educational and activity programs. At the enterprise level, relevant public welfare activities can be actively carried out to support the construction of child-friendly cities.

The construction of child-friendly cities is a systematic project that requires the joint participation of the government, all sectors of society, families and children themselves to form a synergy and jointly promote the construction of child-friendly cities. Only through the joint efforts of the whole society can we create a healthier, happier and more suitable urban environment for children's growth.

In the future development, we still need to constantly summarize and share successful experiences from all over the world, and continuously innovate and explore new paths for building child-friendly cities. Only by constantly adapting to and meeting the needs of children from different cities and cultures can we truly achieve the grand goal of building child-friendly cities. It is hoped that in the future, cities will increasingly attach importance to the healthy growth of children, create a better growth environment for them, and inject more vitality and impetus into the sustainable development of cities.