Analysis of Mega Transportation Projects in Istanbul and Identification of Priority Response Areas and Planning Parameters

ABSTRACT Cities are spaces that are constantly changing / transforming and are directly or indirectly affected by everyintervention, through iterative cycles. Especially in Turkey, urban regeneration practices are taken into consideration only for issues such as production of residential areas and earthquake resistance, whereas transportation policies in urban regeneration regions are not determined ahead ofthe implementation. This has negative effects on urban transportation and sustainability. The displacement of segments of the society through urban transformation interventions causes transportation habits to change in turn, along with changes in the space. In this sense, transportation demand and transportation habits constitutethe main factors affecting the type and amount of spatial interaction in cities. Especially with the implementation of new transportation projects, the type and amount of spatial interaction is changing and existing plans may become unresponsive to the new needs. Increased accessibility affects land use demand, and changes in building conditions in the region affect population, transportation and land prices. These changes alterthe distribution, type and volume of travels in urban areas, and changing commutehabits may cause agglomeration of certain types of transportation, renderingexisting transportation networks inadequate. These problems can be seen in many areas such as public transportation, parking, pedestrian and bicycle flows, private vehicle traffic and accessibility. In this context, in order to evaluate the effect of high-scale transportation investments on urban transformation, socio-economic structure, transportation habits and land prices, Istanbul, with its high-scale transportation investments, has been identified as the area of study. Istanbul’s population and land use structure were thoroughly affected by Marmaray, the Third Bosphorus Bridge, the Eurasia Tunnel and the Third IstanbulAirport investments, which were implemented without being pre-determined by high-scale decisions. Significant changes have been observed in transportation and land prices as a result. Due to the changes created by the mega transportation projects that were implemented, the land use plans that were prepared based on the historical data and the current situation data should be questioned anew. In this study, the effects of four mega projects on land use were investigated. In order to eliminate the problems caused by the increase in transportation demand and land prices, the districts to be prioritized for intervention were identified. New planning approaches / parameters have been developed to mitigate the negative impacts of mega-projects on the districts selected for priority intervention, taking into account the central planning approaches in effect in the selecteddistricts, and a new methodological proposal that explores the principles and approaches that need to be reconsidered in the context of land use and transportation planning balance is presented.