Toplu taşıma odaklı gelişme yaklaşımının Marmaray hattı örneği kapsamında değerlendirilmesi
Evaluation of the transit oriented development approach in the scope of Marmaray line sample
Yazar: KÜBRA PİLATİN
Danışman: DOÇ. DR. PELİN ALPKÖKİN
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / İnşaat Mühendisliği Ana Bilim Dalı / Ulaştırma Mühendisliği Bilim Dalı
Derece: Yüksek Lisans, 2019
Konu: Ulaşım = Transportation

Özet:
2050 yılına varıldığında dünyada kentli nüfusun yaklaşık 2 katına çıkacağı, bu nedenle kentleşmenin 21. yy'ın en önemli dönüştürücü gücü olacağı vurgulanmaktadır. Nüfusun kentlerde yoğunlaşması kentte mekânsal ve sosyo-ekonomik baskı oluşturmaktadır. Bu baskı kentin sürdürülebilir yaşam standartlarını da olumsuz etkilemekte ve eğer müdahale edilmez ise kentlerimizin hayatı kısalmaktadır. Bu gerçeklik karşısında dünyada birçok anlaşma imzalanmakta ve deklarasyonlar yayınlanmaktadır. Genel amaç, kentlerde oluşan bu baskıyı kontrol altına alarak sürdürülebilir bir kentsel gelişme modeli oluşturmak üstünedir.

Kentsel toplu ulaşım sistemlerinin kentin nüfus artışıyla paralel olarak planlanmaması, kentte kontrolsüz mekânsal büyümeyi etkileyen başlıca faktördür. Bir diğer deyişle kentsel yayılma olarak adlandırılan bu durum, özel motorlu araçların kullanımını artırır. Birçok olumsuz çevresel etki oluşturan yüksek oranda özel araç kullanımı, kentsel arazi kullanım dokusu üzerinde de olumsuz etkiler yaratır. Özellikle kentsel donatı ve çalışma alanları kentsel mekanda dağınık olarak yerleşir ve insanların bu gibi fonksiyon alanlarına erişim oranları düşer. Kentsel mekanlarda sürdürülebilirliğin ana politika olduğu günümüz kentlerinde bu olumsuz etkilerin azaltılması elzemdir. Bu bağlamda hem arazi kullanımı hem de ulaşım sistemleri kapsamında sürdürülebilir çözümler üretilmesi gerekir. Sürdürülebilir kentsel gelişme ve sürdürülebilir ulaşım olgularının ikisini de kapsayan ve entegrasyonunu sağlayan ''Toplu Taşıma Odaklı Gelişme Modeli'' söz konusu ulaşım kaynaklı kentsel bozulmaların çözülmesi için bu tez kapsamında model olarak seçilmiştir. Bu model, yüksek kapasiteli bir kentsel toplu ulaşım sisteminin istasyonu veya durağı çevresindeki 500 ila 1.000 metre yarıçaplı alanda planlanır. Kompakt ve karma kullanım içeren tasarım çözümleriyle erişilebilirliğin artırılmasını hedefler. Yapılaşma öngörüleri ile kentsel ve donatı alanları çalışılan istasyon ya da durak bölgesinde yürüme mesafesi olarak tanımlanan alanda çözümlenip, konut ve rekreasyon alanları bu alanın dışında bırakılarak sağlıklı yaşam alanları oluşturmak hedeflenmektedir.  

İstanbul'da güneyde doğu-batı aksında lineer büyüme gösteren kent makroformu, 1950'lerden sonra 1. ve 2. Boğaz köprülerinin yapılmasından sonra, kuzey yönünde büyüme eğiliminde olmuştur. Kent makroformunun gelişiminin kuzeye yönelmesinde, ulaşım kararları sonucunda kentin kuzey kesimlerine inşa edilen köprülerin çektiği trafik ve nüfus etkili olmuştur. Diğer taraftan kentin güneyinde yüksek kapasiteli bir raylı sistem olan Marmaray hattı bulunmaktadır. 2013 yılında hizmeti durdurulan banliyö hattının yenilenme süreci beklenenden uzun sürmüştür. Bu uzun süren yenileme çalışmaları, hat üzerinde yer alan kentsel yapılaşmış çevre üzerinde ve yolcu davranışları üzerinde değişimlere sebep olmuştur. Hattın hizmete açılmasıyla yüksek kapasiteli bir raylı sistem hizmeti kentin güney sahili boyunca çalışmaya başlamıştır. Kentteki diğer raylı sistemlerle tam entegrasyonunun sağlanması halinde, hem güzergâh koridoru hem de entegre olduğu noktalarda kuzey yönünde işletilen diğer raylı sistem hatları boyunca özel araçlarla yapılan yolculukları önemli ölçüde azaltacağı öngörülmektedir. 

Yolculuk davranışlarını etkileyen arazi kullanım kararları ile toplu taşıma odaklı gelişme modeli (TOD) kapsamında uygulamalar yapılması halinde, banliyö hatlarının kapanmasıyla dağılma ve bozulma gösteren hat üzerindeki kentsel yapılaşma kontrol altına alınabilecektir. Hat yolcular için tekrar cazip hale getirilecek ve hattın kapasitesinin etkin kullanımı sağlanacaktır. Ek olarak oluşan çevresel olumsuz etkiler de bu uygulama sayesinde en aza indirilecektir.

Bu çalışma kapsamında Marmaray hattının Anadolu Yakası'ndaki istasyonları incelenmiştir. Hattın ve yolculuk sayılarının büyük bir bölümünü barındırdığı için Anadolu Yakası'ndaki istasyonlar seçilmiştir. 23 istasyon için, belirlenen arazi kullanım bileşenlerinin hesaplanmasıyla TOD endeksi hesaplanmıştır. Böylece istasyonlar TOD modeli için uygun olup olmamaları şeklinde nitelendirilerek, özellikle en yüksek 3 ve en düşük 3 endeks değerine sahip istasyon kapsamında geliştirilmesi gereken arazi kullanım bileşenleri belirlenmiştir.

Abstract:
It is emphasized that by 2050, the urban population in the world will be doubled and therefore urbanization will be the most important transformative power of the 21st century. Concentration of the population in cities creates spatial and socio-economic pressure in the city. This pressure adversely affects the sustainable living standards of the city and if not intervened, the life of our cities becomes shorter. Against this reality, many agreements are signed and declarations are published in the world. The overall objective is to create a sustainable urban development model by controlling this pressure in cities.

Sustainable city contributes to achieving the goal of using clean energy, economically balanced development and social equality of the future. In particular, the design of urban development models based on sustainable transport that prioritizes the types of transport provided by public transport and non-motorized vehicles and the design of land use according to mixed use criteria should be taken as a basis. Cities should be planned in which people can easily travel by foot, bike, bus or train and have access to different urban functions. In addition, urban transport systems should be inclusive of all social groups living in the city.

The fact that urban public transport systems are not planned in parallel with the population growth of the city is the main factor affecting uncontrolled spatial growth in the city. In other words, this term called urban sprawl increases the use of special motor vehicles. The use of highly private vehicles, which have many adverse environmental impacts, also has a negative impact on urban land use patterns. Especially urban equipment and working areas are scattered in the urban space and people's access to such function areas decreases. In today's cities where sustainability is the main policy in urban spaces, it is essential to reduce these negative effects. In this context, sustainable solutions should be produced within the scope of both land use and transportation systems.

The fact that urban public transport systems are uncontrolled spatial growth in the city. In other words, this term is called urban sprawl. The use of highly private vehicles, which has many adverse environmental impacts, also has a negative impact on urban land use patterns. Particularly urban equipment and working areas are scattered in the urban space. In today's cities where the sustainability is the main policy in urban spaces, it is essential to reduce these negative effects. In this context, sustainable solutions should be produced within the scope of both land use and transportation systems.

In the fourth section, Marmaray line, which serves in the metropolitan area of Istanbul, has been evaluated in terms of TOD applicability. The planned and implemented line on the European and Anatolian sides of Istanbul is currently continuing uninterruptedly on the southern coast of Istanbul. The renewal works of the line, which was closed for use in 2013 for renewal purposes, took longer than expected. There has been deterioration in the urban fabric on the line due to long-lasting renovation works. In addition, another bridge was built to the northern part of the Bosphorus during the period of closure. For this reason, it is foreseen that the city will continue to grow in the north, which is the current development direction. On the one hand, the high capacity rail system located in the south of the city, the backbone of the city in the form of macro-public transportation on the one side of the city on the one hand tend to expand in the north direction, the capacity of Marmaray will not be used effectively. No road map has been identified within the scope of the planning studies for Istanbul regarding this problem.

With the closure of the line, negative situations affecting urban space and urban life emerged. Unplanned, uncontrolled urban sprawl, especially after 1950, was directed towards the regions of Istanbul within the natural threshold. As a result of the urban development process driven by road investments, the use of private vehicles became widespread and parallel environmental problems increased. As a result of uncontrolled urban sprawl, the land use pattern has been scattered in the urban space. As road-based urban transport journeys fail to meet the increasing demand, traffic congestion is experienced and journey times increase. As a result of transportation and urban development policies, the rail systems that should form the backbone of urban transportation are not used effectively. Due to the integration problem of public transportation systems, there are problems in pedestrian transportation in urban function areas. For the Marmaray line, which has a high capacity rail system along the southern coast in the Istanbul metropolitan area, an urban development model with a focus on public transportation is proposed to address the above, mentioned problems. 

When the Marmaray project is considered holistically, it is an integrated rail public transportation system in the metropolitan area of Istanbul on the European and Anatolian sides without interruption. The project starts in Halkalı on the European side and ends in the Gebze district of Kocaeli. Of the 43 stations on the route, 3 are underground and 40 are above ground stations. The total length of the line is 76 km. In addition, 12.2 km of the line is the gorge passage tunnel. The line, which runs from Halkalı to Kazlıçeşme, enters the underground at the Yenikapı station for the passage of the Bosphorus and re-emerges at the Ayrılık Çeşmesi station. In order to provide pedestrian-friendly areas where density, mixed use, land use functions, integration to public transportation lines and pedestrian access are provided, and to ensure sustainability in urban areas, parameters were calculated in 1,000 square meters of circular areas in all European and Anatolian sides of the Marmaray line. 

 It is recommended to implement the TOD to ensure that the Marmaray line is a preferred line especially for urban trips and to increase the attractiveness of the line. With the TOD application, the method was established based on the criteria of land use texture of the urban development approach focused on public transportation especially at the stations on the Anatolian Side of the Line. The land use elements identified and the parameters evaluated under these elements are defined in the section. All data obtained in this study were used as input for TOD index. The diversity of data allows for more accurate analysis.

Assessing the benefits of TOD is a complex process that requires a systematic and comprehensive assessment methodology. Nowadays, fuzzy comprehensive evaluation method is widely used in four types of evaluation, called data envelopment analysis, gray relational analysis and analytic hierarchy process. In this study, analytical hierarchy process was chosen to form the evaluation model. Since the data used is limited and the parameters are calculated as a percentage, this method is the most optimal choice. The first step for the calculation of the analytic hierarchy process is to determine the weights for the parameters.

Calculation of weight coefficients is determined as a result of focus group meetings. However, no focus group meetings were held within the scope of this study. The weights were determined by averaging the weights of similar parameters used for the sample projects examined in the literature review. In the next stage, standardization of the values of the parameter calculations will be performed. Since different formulas were used to calculate the parameters, the results were standardized using the maximum-minimum method. This means that the minimum and maximum values convert the actual data values linearly. The transformed data has a value between 0 and 1. Finally, TOD index is calculated by using the preliminary calculations.

In the fifth chapter, the methods, approaches and calculations used in the spatial analysis studies for TOD planning proposed will be presented. Four main topics were identified for evaluation. Intensified built environment, land use diversity, accessibility and pedestrian-oriented urban design are the main topics identified. 12 parameters were calculated under these headings. The density of employment, population and trade area was calculated under the title of Density. Under the title of accessibility and design, the shuffle rate, pedestrian access area, pedestrian road density, green area density, parking lot density and IETT line density parameters were calculated. Within the scope of the title of access to public transportation which is the distinguishing title for this thesis, the density of stops for different transportation systems in the station areas was calculated. Then, the calculated values were evaluated with different analytic hierarchy process and a different TOD index was calculated for each station. With this approach, suitable stations for TOD implementation were identified from the stations classified in the specified intervals.

Within the scope of this study, the stations of the Marmaray line on the Anatolian side were examined. Stations on the Anatolian side were selected because they accommodated a large part of the line and the number of trips. The TOD index was calculated for 23 stations by calculating the land use components identified. Thus, whether the stations are suitable for TOD model or not, land use components that have to be developed within the scope of the stations with the highest 3 and lowest 3 index values have been determined.