Alternative method suggestion for determining areal distributions of urban functions in planning phase: Monte Carlo simulation

The real estate sector is a major shareholder in the Turkish economy, and also the most dynamic sector as well as being the locomotive. Therefore, it will be parallel to the decisions to be taken in the planning stage by taking the right steps at the right time to avoid the mistakes in the sector. However, many problems can be experienced as a result of the planning process and its operations. These are the strategies that can be pursued at the stage of project development, and inability to produce plans which based on consistent and real dynamics. As results of both problems; destroyes in historical textures, traffic, increases on human and structure density, ecological problems, air pollution, unplanned and disproportionate growth are observed and this situation decreases the quality of urban life. Plans far from detailed analysis, which do not take into account market dynamics, and investors' expectations of high profits in a short period of time are a big area of conflict that needs to be considered. The motivation of this study is to propose a method to solve the conflict. The aim of the study is testing the usability of the Monte Carlo simulation method, which can be accommodated in many parameters, in order to determine the spatial size of the urban use functions by entering into the planning phase. Three main commercial functions (hotel, office and shopping mall) have been studied for the Istanbul market. These functions have played a decisive role in urban development in recent years. 15-years projections have been simulated for three functions to determine the stock requirement. In addition, the shortcomings of the planning that was far from market dynamics were emphasized by comparing the simulation results with the existing market. There is legislation in the real estate sector that determines the conditions of structuring. All applications related to the sector are made according to the zoning plans which are products of these legislations. On the other hand, the project developers develop a structure in accordance with these legislation and related plans in the direction of their knowledge and skills. The quick and uncontrollable growth of the city towards the North was the main concern due to the lack of compliance with plans by local authorities and developers. Because it was decided to grow linearly on large scale plans. It was also aimed to create a solution based on more systematic and numerical analyzes in the near future due to the efforts to create more centres in the city and the failures experienced in these experiments. The Monte Carlo Simulation is a method of analysis that determines the parameters boundaries and simulates to work up to. The examined data was evaluated with this method, which was not preferred in the real estate sector before. Variability ranges of those that are thought to be determinants have been analyzed and identified and included in the system. Thus, the simulation is run and 1,000 estimated values are generated for three commercial functions. From this point of view, it can be said that there is more option in the decision phase and that the risk is reduced and more efficient analysis is made. Standard deviation, mean, minimum and maximum values of the results obtained for all three functions are examined. In particular, the standard deviation varies according to the change interval of the parameters. In order to decrease the standard deviations, it is necessary to work with more accurate data. However, there is a gap in this field in Turkey. According to the simulation, there must be 112.000 beds capacity at the end of the 15-years projection in Istanbul. Unfortunately, the existing hotel market has 146.000 beds which is 31% higher than the simulation result. There will be no reduction in this market as the government has to protect investors' acquired rights. Due to the lack of stability of the data, the standard deviation of the simulation is 7,000 beds for hotel market. It observed that the occupancy rates, which is lower than the market's capacity, will be steady for a while for the office market. However, it has been determined that Istanbul needs more than 1 million square meters of office space for 15-years projection. Along with the growth policies in the process, analysis for this market should be kept up to date and not be put in error. It has been determined that the commercial activities in the country are heavily influenced by uncertainty in the economy. For this reason, the standard deviation is about 1 million square meters. After 15 years, it can be observed that the existing office stock is sufficient in İstanbul. It has been observed that when the 15-year projection is applied for the shopping mall market, the market needs and the current density are in harmony with each other. There are approximately 4.6 million square meters of gross leasable area available in Istanbul, and the forecast for the simulation is close to this amount. However, the estimated figure for 15-years projection is 5.4 million square meters and it is necessary to be cautious in this process and to meet the market needs in a controlled manner. For the shopping mall market, the harmony between the data is high and the standard deviation is only 150 thousand square meters. This value is equal to the gross leasable area of one large-scale shopping mall in Istanbul. The inefficient planning in the tourism sector is clearly shown compatible with the motivation and aim of the study. It is necessary to be careful in the plan of each measure for the following process. Although, this must be avoided to leave this issue to the investor's initiative. There is an instant stock surplus in the office market like hotels. However, it is possible to say that the occupancy rates will only below for a while according to the promise of the future for the sector. If it is acted carefully, it can be said that it is possible to catch a market that is economically efficient and satisfies the actors of the market. This study has introduced the response of the market into the planning phase and introduced many non-parametric data in zoning plans into the system and brought a different perspective to the planning with Monte Carlo Simulation. On the other hand, it provided the results that should be taken into consideration during the development process by the project developer, which clearly shows the market response of the market. Thus, a new analysis method proposal has emerged in order to build compatible projects with market needs. With this study, city planners, government agencies and other professionals in the sector can look at the real estate market from a different perspective by expanding their analysis in the planning stage or in the sectoral analysis. Although, they can achieve more efficient results by combining more non-parametric data into the system. Likewise, it is possible to think of a method that opens up the planning of the areal distribution of the units in the project according to the market needs in order to develop the projects which have a high occupancy rate in the development phase.