Regeneration informal settlements using the transit oriented development model (TOD) (case study: Hamedan city)

Introduction
Today, the world is more urban than ever. According to published reports, more than half of the world's population now lives in cities, and according to the United Nations, this number will increase to more than two-thirds by 2050. Urban growth has been accompanied by many problems that have endangered the quality of life of people living in cities. The issue of informal settlements is considered as one of the problems of "developing countries" that have created many problems in physical, cultural and economic dimensions of cities. So solving the problems of this sector is always one of the most important concerns. Therefore at national and local levels, the regeneration of informal settlements has always been one of the most important challenges for urban planners.
So far, several programs and measures have been taken to manage and organize such contexts. They are mainly focused on solving physical problems and have not resulted in significant results other than providing some urban infrastructure. According to statistics, about one third of Iranian urban population lives in these areas. In order to improve the quality of life and maintain human dignity in these tissues, private sector capital could be used through preparing executive plans with low investment risk. In this section, the development model is based on transportation (TOD) as one of the most evolved models of urban development with the optimal use of land around public transportation stations. This can be the basis for economic and social development in these settlements alongside physical reconstruction. In this study, feasibility and prioritization of using this model in the reconstruction of informal settlements located along the second BRT line of Hamadan city has been investigated using the ANP model. The results of network analysis model showed that transportation, urban planning and economic criteria were ranked first to third. Also, according to the indicators (TOD), two stations located within informal settlements, which have a higher density and mixture of users, have gained more points. Also, due to the transit role of the arterial axes of Hamedan, since it connects center and south of Iran to the three western provinces of the country and the traffic of vehicles from this axis, the stations that are closer to the city entrances can functionally take advantage of the TOD pattern.
Materials and research methods
The present study is methodologically descriptive-analytical and based on documentary studies. It is a library and field observation and practical in terms of purpose. Thus, with documentary and library studies, the literature and theoretical foundations of the research have been explained. With field observations, the necessary data and information have been collected in the study area.
In the present study, line three of high-speed bus system (BRT) city of Hamedan and the sphere of influence of these stations in an area with a radius of 800 meters of the station) constitute the research territory(Figure 2). In this regard, in the first part, the stations that are located in informal settlements are identified. Then according to the components of transport-oriented development, the location and prioritization of the optimal station is done to implement the transport development approach. The axis aims to recreate and reconstruct informal settlements using ANP network analysis as well as interpreting its results in the GIS spatial information system. First, according to the characteristics of the study area and reviewing the relevant literature, criteria and sub-criteria for spatial and physical regeneration of marginal textures and informal settlements were selected based on the development approach based on TOD transport. Then, questionnaires were designed to perform pairwise comparisons and were provided to 20 professors and urban planning experts to perform the necessary assessments. After collecting the questionnaires, the geometric mean of the answers was calculated and fed into Super Decisions software for analysis.
Discussion and Conclusion
In this study, after reclassifying the layers, the weight obtained for each sub-criterion in the network analysis process in its respective spatial layer was multiplied using the Overlay Index method and the Raster Calculator tool. Finally, all layers of information were combined and a spatial and physical reconstruction map was created based on the development approach based on TOD transportation in Hamadan. Figure (6) shows the final output of the TOD transport-based development overlap map based on the network analysis model along the BRT line two of Hamedan. It shows that according to the transport-based development indicators, each of the stations has the ability to compress. These stations have a higher user mix and have more points. Also considering the transit performance of the arterial axes of Hamedan in connecting the center and south of the country to the three western provinces of the country and vehicle traffic from this axis, stations that are closer to the city entrances are more functional. They have a higher capability than other stations to benefit from the TOD model. On the other hand, according to the sub-criteria of transportation, including the use of public transportation and the ability to create a ride park, as well as economic criteria such as added value due to TOD implementation, the willingness of the private sector to invest increases. Similarly, sub-criteria of urban planning such as high density, affordable housing, development constraints, etc. indicate that stations located in informal settlements have better conditions than other stations to use development-based models based on transportation.
Results
The aim of this study is to spatially and physically regenerate marginal tissues and informal settlements based on the development approach based on TOD transport in the city of Hamadan. The information and data of four indicators of economic, transportation and traffic, urban planning and cultural, social and demographics were selected, based on the study context. Then using the Dimatel questionnaire the relationship and influence of each of the elements of the decision with each other is determined. In the next step, using the Thomas L. Hourly Quantitative Questionnaire, all decision elements were compared in pairs according to the control criteria. Afterwards, by merging the opinions of experts using the Copeland technique and using the network analysis process (ANP) method and Super decisions software, the weight and importance of each decision element was determined. Finally, using the Calculator Raster tool, in the ArcMap software environment, the digitized layers of each criterion, were combined according to the specified weight of each, in order to create a development map based on TOD transportation in the city of Hamadan. The results obtained from the network analysis model showed that the proximity to the station was ranked first among the sub-criteria of transportation and traffic, mixed use and high density were ranked second and third among the urban planning indicators, respectively. Also, among the studied economic factors, the sub-criteria of income status of individuals received the highest score compared to other indicators. The sub-criteria of cultural and social status and literacy status of the cultural, social and demographic criteria had the least weight and importance among the elements of development based on TOD transport.
Findings of this study show that due to the transit role of arterial axes in Hamedan, compaction and user mixing indices have more points. Also due to the connection between the center and south of Iran to the three western provinces through Hamedan and vehicle traffic, the axis of stations that are closer to the city entrances have a higher functionality than other stations to use the TOD model. According to the results of this study, suggestions for development based on TOD transportation in the city of Hamadan are presented:
1) Considering the necessity of adapting the land use and transportation system in determining the development pattern of the city, comprehensive and detailed plans of Hamedan city should be prepared at the same time and in accordance with the transportation planning plans.
2) Considering that most of the informal settlements in Hamedan are located along the three BRT lines of Hamedan, using the transportation-based development model can be a powerful tool to regenerate these settlements.
3) Considering the growing use of cars in cities, it is possible to help increase the efficiency of the transportation network by managing land use by using integrated public transportation systems.
4) Considering that one of the most important issues and problems of informal settlements is the problem of unemployment, by using the development model based on transportation, it is possible to help create job opportunities for the residents of these areas.
5) Instead of creating infrastructure to facilitate the movement of cars and encourage citizens to use private cars, public and non-motorized transportation can be developed, such as bicycle lanes.