Abstract

Introduction: During the COVID-19 pandemic, restrictions on human mobility caused health problems. Therefore, it is valuable to evaluate the human mobility restrictions during the pandemic from the population health viewpoint. This study aimed to clarify the correlation between changes in human mobility types and medical costs of lifestyle-related diseases during the pandemic.

Methods: The study design was set as a cross-sectional study regarding the human mobility types and the medical cost of lifestyle-related diseases. The population was Japanese people. Boosted tree analysis analyzed the nonlinear relationship between human mobility types and medical costs of lifestyle-related diseases in Japan. The boosted tree analysis can obtain high accurate models.

Results: The results of this analysis indicated that medical costs were differently affected by walking, driving, and public transit, depending on the type of prefecture. Increasing walking by over 70% reduced the medical costs of lifestyle-related diseases, even during the COVID-19 pandemic. In metropolitan prefectures, the total effect on medical cost was higher for walking and public transit. In addition, medical costs decreased by gradually increasing public transit use by over 110%. On the other hand, in other prefectures, the total effect of public transit was lower than driving, and medical costs increased from 80% to 160%. These results were significant because they indicated the target value for each human mobility type in metropolitan areas and other prefectures.

Conclusions: In conclusion, this analysis indicated that increasing walking and public transit use correlated with a decreasing in the medical costs of lifestyle-related diseases even during the COVID-19 pandemic. The results were significant because they indicate the target value for each human mobility type according to the metropolitan and the other prefectures. Based on the target values, our findings implicate that governments can take measures other than restricting walking and public transit during the pandemic.

In Japan, where the population is declining and aging significantly, walkability has attracted attention as a way to improve residents’ lifestyles. Therefore, it is essential to identify the residential clusters where walkability improvement would contribute to the maintenance of the population in order to select urban areas for the implementation of walkable designs. This study aimed to identify the residential clusters in which walkability affects the future population from the perspective of real estate prices. The reason for focusing on real estate prices is that they are expected to be a confounding factor connecting walkability and the future population. The method we used was to analyze the structural equation modeling of the impact of walkability index, real estate prices, and future population change ratio. This analysis was based on the neighborhood association scale. This study clarified that effective residential clusters are the business center cluster and the sprawl cluster. In the business center cluster and the sprawl cluster, the price of apartments for sale is the real estate value, through which the walkability index positively impacts the future population change ratio. This means that it is expected to contribute to the maintenance of the future population through a combination of walkable designs and housing policies that encourage people to change their residence types to apartments for sale when rebuilding old building stock using the location optimization plan policy.

This study aimed to clarify the effect of walkability on urban sustainability, according to the types of residential clusters in the Osaka Metropolitan fringe area. For this purpose, this study analyzed the statistical causal relationship between the Walkability Index and the Ecological Footprint to Biocapacity (EF/BC) ratio of each residential cluster. The EF/BC ratio is the ratio of the ecological footprint of the biocapacity of the residential clusters. As a result, the effect of walkability on urban sustainability was clarified depending upon the types of residential clusters in the Osaka Metropolitan fringe area. Specifically, it was found that the Walkability Index negatively affects the EF/BC ratio in the sprawl cluster. This suggests that, in the sprawl cluster, active efforts to improve the Walkability Index can contribute to the realization of SDGs (Sustainable Development Goals of the 2030 Agenda). However, Walkability Index has a strong positive effect on the EF/BC ratio in the old new-town cluster, etc. For the residential clusters, the results of this study suggested that there is a necessity to improve urban sustainability through approaches other than improving Walkability.

Urban shrinkage is a problem that is faced by some metropolitan areas globally in urban cities faced with depopulation. Therefore, these cities require “smart shrinking”, which consists of design methods intended to satisfy residents’living needs, even though the population is declining. The purpose of this paper is to develop a walkability indicator for visualizing smart shrinking. The methods include statistical analysis by GIS analysis and questionnaire in the Northern Osaka Metropolitan Area where there are many small-sprawl areas. The following four results were identified. First, the population decline in sprawl areas indicates the regional characteristics of each city. Second, this paper develops a walkability indicator composed of household density, convenience of facilities, road connectivity, and traffic safety. Third, Wi(i), which is walkability in each residential area, in sprawl areas, and in public housing areas, is important for future population change. Finally, the validity and effectiveness of the indicator is clarified by questionnaires regarding regional evaluation. In conclusion, the walkability indicator is able to visualize smart shrinking in sprawl areas.