Study on Dual Strategies for a Local City in the Aging Society-Planned Retreat from Suburban Areas and Restructuring of Central Built-Up Areas

这项研究以爱知县丰田市为个案，指出在人口迅速减少和老龄化的情况下，日本地方城市需要“有计划地撤离郊区”和“重建中心建成区”的双重策略，并指出了实施的实际方法论。对未来形势的考察：生活质量、基础设施维护成本和环境负荷是分析可持续城市形态的基本因素，并指出了双重战略的必要性。通过发电计算法对密集城区降低基础设施维护成本的效果进行了评价。政治目标的评价指标：提出了一种多维的评价方法，用于评价生活质量、基础设施维护成本和环境负荷。将其应用于城市形态的检验，结果表明，集群型城市形态在提升城市生活质量方面是合适的。建成区物理设计：开发了用于研究建成区设计的三维虚拟城市形态自动生成系统。几种设计方案的比较表明了向下分区策略的重要性。考虑家庭内部汽车使用的最优化，研究了邻里汽车共享的最大潜在市场。实证分析结果表明，平日可减少约35%的家庭机队，周末可减少约55%。管理方案：通过对先进案例的研究，确定了私人非营利组织在密集区开发中的作用。研究了TDR(发展权转让)对农田开发的遏制及其对城市绿化的影响。

This study, of which Toyota City in Aichi Prefecture is selected as a case, shows that the dual strategies, namely "planned retreat from suburban areas" and "restructuring of central built-up areas" are required for Japanese local cities under the rapid population decline and aging, and indicates the practical methodologies for implementation.1. Examination of future situation: Quality of Life (QoL), infrastructure maintenance cost, and environmental load are the fundamental factors for analyzing sustainable urban form, and that the necessity for dual strategy is indicated. The reduction effect of infrastructure maintenance cost by compact urban area is evaluated through Generation Accounting method.2. Evaluation indices for political goals : A multi-dimensional methodology for evaluating QoL, infrastructure maintenance cost, and environmental load is developed. This is applied to the examination of urban form, and the result shows that cluster-typed urban form is appropriate in terms of QoL improvement.3. Physical design of built-up areas : The automatic generation system for 3-dimensional virtual urban form to examine the design of a built-up area is developed. Comparison of several design scenarios shows the importance of down zoning policy. Maximal potential market for neighborhood car sharing is investigated considering optimization of car use within household. Results of empirical analysis suggest that household fleet can be reduced by about 35% on weekdays and about 55% on weekends.4. Management scheme: The roles of private nonprofit organization in the development of a densely built-up area are identified by the research about the advanced case examples. The containment of development in farmland by TDR (Transfer of Development Rights) and its impacts for urban greening are examined.