Tanaka Koichi
Associate Professor, Institute of Socio-Arts and Sciences
University of Tokushima, Japan
Introduction
Approximately 20 percent of the total emission of C02 in Japan is produced by the transportation sector. The reduction of traffic volume is important for the reduction of C02 emissions, even though hybrid cars are gradually becoming more widely used. Traffic jams are still serious problems in small cities and cause considerable C02 emissions. Since public transportation is better-developed in metropolitan areas, most people there depend on it. However, in smaller areas, where public transportation is not as large-scale, the majority of people have their own car. Although many TDM projects have been addressed in small cities in Japan, they still have little effect on reducing C02 emissions.
The spatial mismatch between a city planning area and an actual urban area can be pointed to as one of the essential reasons for the low rates of passengers in the public transit of smaller cities. Urban areas usually consist of multiple municipalities, and many people commute a long way from suburban areas to city centers. Therefore, the planning of public transportation should consider the whole of an urban area. However, urban areas are divided into numerous city planning areas in many parts of Japan. This is a barrier for planning and building an adequate public transportation system that can reduce environmental loads.
This article focuses on the problems stemming from the spatial mismatch between a city planning area and an actual urban area in order to clarify the effect of this mismatch on environmental loads in small Japanese cities. Moreover, the appropriate combination of both public transport and land-use regulation in city planning as a way of reducing environmental loads is investigated.
Study area
The Tokushima urban area on Shikoku Island in Japan is examined in this study (Figure 1 a). Tokushima City, with a population of 267,000, is the capital of Tokushima Prefecture. Approximately 621,000 people live in the surrounding area and account for three-quarters of the population in the prefecture. The urban area is about 1,384 square kilometers, which covers about one-third of the entire prefecture.
From the perspective of city planning, this urban area is divided into three areas: Tokushima Tobu city planning area, Aizumi city planning area, and non city planning area (Figure 1 b). Most of the central urban area is included in Tokushima Tobu city planning area, while Aizumi city planning area includes only the town of Aizumi. An urbanisation promotion area and an urbanisation control area are defined in order to control urban sprawl in the Tokushima Tobu city planning area.
Figure 1. study area
Neither an urbanisation promotion area nor an urbanisation control area, however, have been defined in the Aizumi city planning area since the beginning of the application of city planning laws in 1968. Therefore, considerably loose regulation has been applied for land use in the area.
Population growth caused the urban area to expand due to the flow of migrants from farming and mountainous areas; this growth has been occurring since the high economic growth period of the 1950s. The population of satellite towns to the north of Tokushima City has increased rapidly since the 1960s (Figure 2). These towns are accessible to the central part of Tokushima City and are well-suited for residence because most area is flatland. From 1970 to 2000, the population increased threefold in Aizumi. Much of the farmland was converted to residences due to the loose regulation of land use. As a result, various types of land use, such as residences, farmland, industries, and commerce, are diversely distributed in whole area of Aizumi. Aizumi and Kitajima are focused on in this paper so that the effects of the environmental loads and the differences in urban policy can be compared in the following analysis.
Figure 2. Change of population, 1950 -2005
Methodology
This study consists of two analyses. First, the changes in land use from 1976 to 2006 are quantitatively clarified in the two towns. Specifically, the area of land that is converted from farmland to urban land is measured by using GIS. Spatial digital data of land use by 100 metre grid squares is used in the analysis. Second, the relationship between the distance to public transportation and the conversion of land use is investigated. The point data of bus stops and stations is made to clip the 500 meter buffered area. Land conversion in the buffered area is compared with the same type of areas in the other towns.
Transportation usage
About 37.4 percent of workers commute to Tokushima City in Kitajima and in Aizumi it is about 30.8 percent (Figure 3). The number of commuters from to Tokushima increased from 3,544 to 4,914. In 2005, approximately 9,000 people commute altogether from the two towns into Tokushima. However, three-quarters of commuters use cars and do not depend public transit (Table 1). Therefore, there is heavy traffic in the morning and in the evening in the Tokushima urban area. Furthermore, the broad Yoshinogawa River cuts through the northern part of Tokushima City and gets in the way of commuting traffic. Since only four bridges span the river, many cars accumulate on them while traveling to the central part of Tokushima. Those bridges are bottlenecks for traffic and have often heavy traffic jams. A train bound for Tokushima Station operates every twenty minutes during the morning, and a bus operates every thirty minutes in Aizumi. Few workers use them; although many students do. For a long time the Tokushima urban area has always had traffic jams. Despite attempts at TDM (Transport Demand Management), such as the system of park and ride, traffic problems have yet to be solved. City master-plans do not mention IDM, but instead the construction of new roads in order to reduce traffic jams. Moreover, concrete measures against traffic jams between Aizumi and Tokushima are not shown because of the inadequate division of city planning area.
Figure 3. The change of commuting to Tokushima, 1990-2005Source: National Census
Table 1. Transport mode used for commuting
Land use change Figure 4 shows of the change in the use of farmland from 1976 to 2006 within the study area. While little farmland are found around the central urban area of Tokushima city, far more farmland remained in the satellite towns since 1976. Farmland was converted to urban land use exponentially during this period. Although farmland occupied most of the area in Aizumi in 1976, approximately half of all farmland was converted to residences by 2006. Due to its lower land prices, many workers in Tokushima city bought a single-family house in those towns and immigrated there with their families.
Figure 4. Land use conversion, 1976 -2006
Estate development was started earlier in Kitajima than in Aizumi because of its easier access to central Tokushima. Approximately 200 hectares of farmland was urbanised in three decades. As the remaining farmland dwindled in Kitajima, estate development was advanced in Aizumi. More than 300 ha of farmland were exponentially converted to urban land use. As a result, these developments complicated urban sprawl in Aizumi. As shown in Figure 4, while the division of urban area and farmland is relatively clear in Kitajima, both urban areas and farmlands are mixed far more diversely in Aizumi.
Relationship between public transport and land use
As mentioned above, most of the workers who live in Kitajima and Aizumi use cars to commute. Investigated here is the relationship between accessibility to public transportation and population distribution. Figure 5 shows the population that lives within 500 meters, in road distance, from a bus stop or a train station. Approximately two-thirds of these people live in Kitajima. On the other hand, about half of people live an area over 500 meters from bus stop or a train station in Aizumi. This means that for most people who live there, it is not easy to take public transportation. The reason for this is that estate development was widely dispersed around the area of the town. Many people began to live in areas not accessible to public transportation because they own cars and did not depend on busses or trains. Figure 6 shows the percentage of farmland that was converted to urban land use in the area within 500 meters of bus stop or train stations station from 1976 to 2006. Approximately half of the farmland was converted in Kitajima, while in Aizumi only one-third of farmland was converted. It is clear, then, that much of the farmland was converted to residences in the area over 500 metres from bus stops or train stations in Aizumi.
Figure 5. Population by the distance from a bus stop or a station
The reason why numerous estates were developed in Aizumi is because of loose regulation of the Aizumi city planning area. New estates were developed around existing urban areas in Kitajima. This expansion of the urban area was controlled by the division of urbanization. Newer estates are accessible to bus stops too, because bus stops are located along the main road in the existing urban area. However, many estates were developed in areas further away from the existing urban area in Aizumi, again due to lose regulation. Since the price of land is expensive in the urbanised promotion area of Kitajima, people who want to buy a house prefer buying in Aizumi. As a result, residents have increased in the areas where busses and trains are less accessible.
The reason for this is that estate development was widely dispersed around the area of the town. Many people began to live in areas not accessible to public transportation because they own cars and did not depend on busses or trains. Figure 6 shows the percentage of farmland that was converted to urban land use in the area within 500 meters of bus stop or train stations station from 1976 to 2006. Approximately half of the farmland was converted in Kitajima, while in Aizumi only one-third of farmland was converted. It is clear, then, that much of the farmland was converted to residences in the area over 500 metres from bus stops or train stations in Aizumi.
Figure 6. Converted area of farmland to urban land use in the area within 500 metersfrom a bus stop or a station, 1976-2006
The reason why numerous estates were developed in Aizumi is because of loose regulation of the Aizumi city planning area. New estates were developed around existing urban areas in Kitajima. This expansion of the urban area was controlled by the division of urbanization. Newer estates are accessible to bus stops too, because bus stops are located along the main road in the existing urban area. However, many estates were developed in areas further away from the existing urban area in Aizumi, again due to loose regulation. Since the price of land is expensive in the urbanized promotion area of Kitajima, people who want to buy a house prefer buying in Aizumi. As a result, residents have increased in the areas where busses and trains are less accessible.
Loose regulation of land use causes not only urban sprawl but also an increase in residents that cannot access public transportation. It is difficult to increase the users of public transportation, even when lDM and MM (Mobility Management) are applied. Therefore, enviromnental loads are increased because of two aspects: the urbanization of farmland and the increasing of dependence on cars. Consequently, the loose regulation of land use in Aizumi thwarts any attempts to reduce environmental loads that are addressed by the urban area as a whole. Although proper regulation of land use is applied in much of the urban area, the tremendous influx of population caused chaotic estate developments in Aizumi. If the urban area was not divided into two city planning areas, chaotic estate development would be better controlled, since most of the people live in the urbanization promotion area. Different land regulations in urban areas prevent balanced development, and can reduce environmental loads. City planning area must be used to conform to the actual urban area.
Conclusion
In this paper, the problem of spatial mismatch between city planning areas and an urban areas is pointed out in order to prove that the differences in the regulation of land use prevents the reduction of environmental loads in small cities in Japan. Since there are many urban areas in Japan that include multiple city planning areas, it is immediately necessary to correct these mismatches. What’s more, population distribution needs better long-term regulation to have a positive effect on environmental loads. Specifically, the conversion of farmland into urban residences needs to be regulated on the basis of the distance to a bus stop or a train station. Improved regulation will contribute to an increase of population in urbanization promotion areas, and greater numbers of workers who commute by public transport.
From a social standpoint, since the Japanese population ages at a faster rate than the rest of the world, population distribution should be aggregated in areas with decent public transit. Numerous elderly people who live in areas far away from retail stores must drive cars if they live in smaller cities. Some of them cause traffic accidents, however, and occasionally lose their lives. Fatal car accidents caused by elderly people are increasing and are becoming more and more a social problem. Regulation of land use needs to be linked to public transportation in order to realise a reduction of environmental loads and the safety of the aging society.
Notes
1) Municipalities where ten percent of workers commute to Tokushima City are defined as an urban area of Tokushima in this study. Tokushima consists of five cities, eight towns, one village, and a part of another city.
2) As a rule, most of city planning areas are divided into urban promotion areas and urban control areas by a city planning law in Japan. The former is defined as an area where urbanisation will be promoted throughout the decade, while the latter is defined as an area where urbanisation should be controlled. Others in city planning area are referred to as non-designated area.
3) Although it is commonly called a ‘100 meter grid square data,’ the grid is not exactly, but rather approximately, 100 square metres. The grid is 4.5 seconds long in longitude and 3.0 seconds wide in latitude.
