**4. Role of planning support tools for urban planning**

As mentioned in sections 2 and 3, in order to induce residents to the areas with a low risk of natural disasters and to conduct measures for disaster mitigation in the areas where it is difficult to induce residents, it is necessary to proceed with planning through discussions involving not only the local government but also residents and the relevant parties.

One of the support methods for that purpose is the development and utilization of planning support systems (PSSs). This section introduces examples of PSS and indicates its role.

#### **4.1 Induction of residents considering improvement of mutual assistance ability**

#### *4.1.1 Background and objective*

When a large-scale earthquake occurs, many residents need rescue and evacuation support at the same time. In this situation, only assistance activities by organizations of the national government and local government (public help) are not able to support all persons who need someone's help. This generates an increase in human damage. In order to reduce such human damage, mutual assistance activities among residents are important. Therefore, enhancing the mutual assistance capacity of the district is important. For this reason, it is important to secure people who can carry out mutual assistance activities, such as leading young households to the areas with low capability of mutual assistance.

Based on that mentioned above, in this section, through the practice in the model area, the examination method of improving the capacity of mutual cooperation introduces the concept of improving the capacity of mutual assistance and the role of planning support technology.

In addition, the importance of a compact urban structure will be mentioned from the perspective of improving the ability of mutual assistance activities.

#### *4.1.2 Outline of the PSS and the concept of the mutual assistance*

The PSS for promoting the ability of mutual assistance was developed by the authors. The details of the PSS are described in the reference [7]. This section shows the outline of the PSS.

The mutual assistance activities described in this paper mainly consisted of these two activities: (1) evacuation support behavior to nearby residents who were unable to evacuate alone due to declining physical functions due to aging or disabilities. (2) When a resident discovered a victim such as a buried person by rubble in need of help within the evacuation route during the evacuation, they take part in the rescue activities within a reasonable range while ensuring safety.

In order to extract the areas where the ability of mutual assistance activities is low, the authors' laboratory has developed a PSS to evaluate the ability of mutual assistance using GIS that enables quantitative evaluation by building units (**Figure 4**). In this

*Trends in Urban Planning and Measures of Disaster Risks in Japan – Roles... DOI: http://dx.doi.org/10.5772/intechopen.109461*

evaluation method, based on the number of local residents, gender, and age, physical strength, implementation rate, and activity rate (1) are multiplied according to **Table 1**). Then the expected value of mutual assistance activities under the situation of a large-scale earthquake disaster is calculated. After that, the expected value is weighted by distance based on the assumption that residents take some time to discover or recognize those persons who cannot evacuate without some assistance, in accordance with the distance.

It is indicating that if one person is caught in the rubble generated by the collapse of the building with less than one ability of mutual assistance capacity, the person does not receive sufficient mutual assistance from the surroundings.


**Table 1.**

*The expected value in accordance with age and gender.*

#### *4.1.3 Evaluation of the ability of mutual assistance in model district*

The model district is located in the Ushikubo district of Toyokawa City, Aichi prefecture in Japan. The Ushikubo district was selected according to the result of the evaluation and extraction of the districts with a high risk of the earthquake disaster in Toyokawa city, which was carried out in cooperation with Toyokawa city and the authors' laboratory in 2014 [8].

Based on the results of the survey, from 2015, the district started specific community-based activities for disaster mitigation with a view to improving densely built-up areas. The model area is one of the residents' associations included in the Ushikubo district. It has a high awareness of disaster prevention activities and has been proactively continuing disaster prevention efforts for more than 10 years.

The location of the model area is within walking distance from the railway station (JR Ushikubo Station). It is included in the residential promotion area announced in Toyokawa City's location optimization plan (**Figure 5**).

Regarding the data collection, first, a questionnaire was done for all households in the district in order to obtain the necessary information for evaluating mutual assistance. Distribution and collection of the questionnaire were carried out through the cooperation of the neighborhood association.

For those households that did not join the neighborhood association, questionnaires were distributed directly to their mailboxes and collected by mail. The recovery rates were 97% (128/132) and 14% (7/50), respectively. The items of the questionnaire were the number of household members, gender, age group, and the number of people who required special care.

The evaluation results of the ability of mutual assistance and the number of people who need assistance are shown in **Table 2**. The followings are the details of each items in **Table 2**. The maps of the evaluation are shown in **Figure 6**.

**Figure 5.** *Location of the target area.*

*Trends in Urban Planning and Measures of Disaster Risks in Japan – Roles... DOI: http://dx.doi.org/10.5772/intechopen.109461*


**Table 2.**

*Evaluation results of the ability of mutual assistance.*

**Figure 6.** *Map of evaluation results of the ability of mutual assistance.*


In the questionnaire, a person under 10 years old was regarded as a person who needs assistance. However, if it is an infant, it can be carried by one adult. If it is older than an infant who can walk, it is thought that one adult can hold hands and guide him/her to evacuate.

Therefore, the number of people under 10 years old was grasped in the questionnaire.


#### *4.1.4 Possibility of improving mutual assistance through residential induction*

From the perspective of improving the ability of mutual assistance, if residential induction of young households, such as those of the child-rearing generation, is encouraged in the areas where the ability of mutual assistance is low, it is thought that the ability of the area will increase.

As a method of residential induction, for example, in Toyokawa City, the model area is located, new residents who move into the urban function induction area from other cities or from the designated disaster-predicted areas in Toyokawa city have been given Machinaka subsidy.

The subsidy is such as equivalent to the property tax of housing and land for up to 3 years (with an area limit) and a child-rearing incentive (100,000 yen per person for junior high school students and younger, one-time only).

By applying such a subsidy system to the areas where improvement of mutual assistance is necessary within residential promotion areas where improvement of mutual assistance, it is conceivable to strategically induce young households.

Of course, it seems not easy to guide the selection of residential areas into the residential promotion areas. Furthermore, induction into the narrowed areas is more difficult.

However, the areas like the model district of this study, which are close to railway stations, have high population density even within the city and are close to facilities for child-rearing such as elementary schools, have a high potential for inducing residents. Therefore, it seems to be worth considering induction the residence.

As already mentioned in Section 3, in June 2020, the preparation of "disaster prevention guidelines" was added to the Location Normalization Plan.

The areas with high disaster risk should be excluded from residential promotion areas in order to suppress new location in principle. In the areas with high risk in the residential promotion area, the plan to mitigate the disaster risk should be incorporated in the Location Normalization Plan and conducted to achieve the contents in the plan.

Considering the policy, although it is not a designated disaster risk area, a district like a model district with a high density of old wooden buildings in a densely built-up area and a high disaster risk against earthquakes might be examined to exclude from the residential promotion area.

On the other hand, the countermeasures for disaster mitigation as the disaster prevention guideline, the model area has enough activities for disaster mitigation such as grasping the people who cannot evacuate alone, examining evacuation support for those who need support, and activities for improving the ability of mutual assistance.

The areas with active activities for disaster mitigation such as the model area might be examined to include in the residential promotion area as an incentive. The promotion of activities for disaster mitigation might be expected if the discussion of this incentive system is deepening.

#### **4.2 Improvement in densely built-up areas of the residential promotion area**

#### *4.2.1 Background and Objective*

In Japan, there still remain many densely built-up areas, and the promotion of safety in these areas is a pressing issue for urban planning. However, improvement in these areas has been very slow. Exploring draft plans through collaborations between local governments and local residents is essential in order to promote improvements aimed at the improvement of safety, living environment, and townscape.

Therefore, citizen participatory workshops are used nationwide to reach a consensus among stakeholders. However, it is difficult to reach a consensus. This is a key factor to promote improvements in these areas [9].

This study aimed to try to develop a PSS for discussion of workshops to examine draft plans and to verify the usability of using PSS to reach a consensus.

Authors focus on the following two issues as inhibiting consensus building: (1) The lack of a method that can quantitatively and objectively evaluate the earthquake disaster vulnerability of the subject area in order for participating residents to easily understand the effects of improvement plans; (2) The lack of a method for participants to share their understanding of spatial townscape images in combination with disaster mitigation performance evaluation (DMPE) during the discussion exploring the draft plans. The authors explain the outline of a PSS for exploring improvement draft plans of unified DMPE1) in real time with a function providing spatial townscape images by coupling Web-GIS and Virtual Reality in order to solve the above issues.

#### *4.2.2 Outline of the developed PSS*

#### A.Constitution

The PSS we propose in this paper primarily consists of a Web-GIS system incorporating the DMPE method (Web-GIS support system) and a system for exploring spatial townscape images using a VR viewer (VR support system) (**Figure 7**). The details of the PSS are described in the reference [10]. This section shows the outline of the tool.

#### B. Function of the Web-GIS support system

The Web-GIS system we developed has two functions. The first function computes DMPE and compares the results. By using this function, users can evaluate current disaster risk conditions or improvements in safety after the contents of draft plans have been implemented in the form of visual information. The other function is the support for the exploration of draft improvement plans. This system can be used in various types of communitybased activities such as those geared toward increasing disaster mitigation awareness and exploring draft plans for disaster risk improvements. We

*Trends in Urban Planning and Measures of Disaster Risks in Japan – Roles... DOI: http://dx.doi.org/10.5772/intechopen.109461*

**Figure 7.** *System configuration of the PSS.*

assume that this system is operated by local governments and helps community-based activities geared toward disaster mitigation.

In order to tightly couple the system that uses a VR viewer to explore spatial images to the Web-GIS support system, we added a function that outputs the information contained in draft plans to the system (Function c). Using this function, users create "the text data to transfer the information in the draft plan" and save it on the client PC. After that, users read it and display spatial images reflecting the contents of the draft plan using the VR support system. In the draft plans, the proposed improvements can include road improvement such as the widening of narrow roads and the establishment of new roads in densely built-up areas; building improvements such as the reconstruction of those with high fire hazard risk and risk of collapse; establishment of new parks to create evacuation sites, fire prevention zones, green space, community space, etc. Thus, users can visualize the effect of building reconstruction and removal, the establishment and widening of roads, and the removal and establishment of parks as specified in the VR data applied to the current condition by using the support tool. When reconstructing a building, ideally the support tool needs to have a function that allows users to freely change the elements of the building such as figure, size, texture of wall and roof, etc. To achieve this, the support tool needs vast amounts of VR data. However, if the method adopted directly allows users to select the texture of a building from an overwhelming amount of data, users may feel that the tool is too difficult to use. Thus, a method that allows users to select the data from some options carefully selected in advance is more useful than the way mentioned above. Moreover, our aim is to contribute to community-based planning by facilitating collaboration between local governments and local residents using a method that

**Figure 8.** *Using image of the support tool.*

enables gradual improvements over time until consensus among participants is achieved. We cannot assume that the improvement method will achieve consensus all at once. Therefore, the range of design for reconstruction needs options that blend in with the around present townscape so as to keep the district townscape harmonized after improvement. Consequently, we added a function for a library of rebuilding plans with a tool that users can use to select building data from the library when exploring a draft plan (Function d). This library consists of several rebuilding explored by expert in advance and register them in the database of the server.

We assume that these rebuilding data are changed and updated based on opinions participants said in the WS exploring draft plans.
