A model for spatial integration of metro station entrances with the city: The case of Istanbul metro stations

The increase in automobile dependence led to insufficient road infrastructure and traffic problems in the city. As private vehicle ownership increases, railed systems have caused idle spaces in the city. For many years the solution to the traffic problem has been to make more roads instead of improving these railed systems. There was no solution to the traffic problem in the city and problems such as noise and pollution emerged. In addition to being a solution to these problems, rail systems with aesthetic and ecological advantages have come on the agenda. Today, many countries are faced with problems such as rapid population growth, environmental pollution, and intense urbanization. Because of this, in many cities, railway systems with high passenger capacity, ecological, low operating cost without causing traffic congestion have begun to be preferred. Although all these positive aspects of rail systems have caused some problems. Metro stations and their vicinity which are frequently used throughout the day, metro lines intersect with the city are areas that do not respond to the expectations of the users and which do not make a positive contribution to the urban life and this problem is seen in many developing countries. Because of these reasons, in many countries around the world, metro stations are at the intersection of the aims of increasing land use and providing a holistic transport system. Under the title Transit / Transportation Oriented Development, the development of subway stations and their surroundings has come on the agenda. Transport-oriented development and metro stations have come to the fore with the development of the subway lines, the start of commercial service, the attraction point for the region, the concerns about the continuity of automobile-dependent urbanization. The problem that the station and its surroundings do not have a spatial relation with the city is also observed in Istanbul. Areas where the metro stations spread throughout the city (0.00 elevation) can not provide a spatial integration with the city. According to Bertolini & Spit (1998), the way for metro stations to establish spatial integration with the city goes from discovering that the stations are a node that provides access to both trains and other transportation networks, as well as a place consisting of buildings and open spaces. The metro stations, which have two points, namely the node and the place, have the potential to become a place of transportation even though they come to the point of being a transportation point. On the grounds of the metro stations, the entrance spaces that are the intersection with the city carry a potential to be a public space. In the beginning, only the areas that meet the need for transportation are now becoming urban spaces. The thesis study identified the subway station entrances as problem areas and the four main parts (introduction, literature study, field survey, conclusion) that shape this problem. The study begins with an introduction that explains the purpose, scope, literature contribution, research questions and methodology of the research study. In the second part of the thesis has been mentioned urban transportation, rail systems and the conceptual analysis of the relationship of metro lines with the city. Selected 18 subway stations introduced then the reasons for choosing these areas were explained and analyzed, the findings of the field survey were evaluated. Then, the results of the factor analysis and clustering analysis were evaluated, the node and place values were calculated with the data set belonging to the stations and they were scaled at 0-1. In the conclusion of the study, as a result of the evaluation of the findings, the variables that are effective in the integration of the metro stations with the city are revealed. Other researchers have been given clues about similar studies in the future. The purpose of the study is to question how subway stations and their surroundings can achieve successful spatial integration with the city, to create a model of how to improve the spatial characteristics of the urban areas formed at the station entrances. It is also aimed to question the applicability of the node-point model presented by Bertolini (1999) in Istanbul subway stations. Site selection in the field study for the successful establishment of spatial integration of the metro stations and the nearby city and the improvement of the spatial characteristics of the urban areas formed at the entrance of the stations was made considering the type of physical space the station met with the city. For the study, 18 metro stations with different entrance areas were selected in Istanbul. In the selected 18 areas, a six-step method was applied. At the first stage, typological analysis and a typological classification consisting of four groups of stations was carried out at metro stations in Istanbul. In the second stage, eighteen selected sites were observed. It has been observed how users use the entrance spaces of the stations, what activities they do, and how often they do them. Observations were conducted on Mondays and Wednesdays, two typical days selected from the beginning and the middle of the week. The observation ranges were determined as 09.00-09.30 in the morning, 12.00-12.30 in the noon and 18.00-18.30 in the evening. The video recording was done by using the camera as the observation recording tool. In the third step, all the variables revealed by different researchers in the literature are put together and the variables to be used in metro station areas in Istanbul have been determined. In the fourth stage, variables of each station were entered into the SPSS 24.0 program and then factor analysis was used to determine whether variables were more meaningful to each other and which variables were more effective. At the fifth stage, the data sets belonging to the stations are put into clustering analysis and it is investigated whether the stations form meaningful groups with each other. At the sixth stage, the variables belonging to each station are scaled in the range of 0-1 with the 'Minimum-Maximum Normalization' method and the locations of the metro stations are determined in the node-point diagram. When the data obtained from the field survey and analysis are evaluated, it is seen that the metro stations in Istanbul are connected with the city through four places which are square, green space, parking area and highway edges. In clustering analysis, it has been observed that the stations that emerged from the square and the green area formed a cluster, while the parking lot and the autostatic stations formed another cluster. The same result was obtained when the variables of the stations were rescaled by the maximum-minimum normalization method. Thus, it was concluded that the node and place values of the metro stations are related to the type of the space they are leaving in the ground. Also as a result of the factor analysis, 'level difference and the population' variables were removed from the analysis because of their low common variance. In other words, these two variables have no relation to the node and place values of the metro stations. Variables with the highest variance are 'tram / direction number, tram / frequency, proximity to motorway, number of workplaces, activity variety, activity frequency, visibility. In other words, the node and place values of the metro stations are most affected by these variables. In addition, seven new variables were added to the model (axis number, number of ferry directions, ferry frequency, activity diversity, activity frequency, visibility, level diference) the applicability of the model is provided in Istanbul.