TR Dizin İndeksli Yayınlar / TR Dizin Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7149

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  • Article
    The Relationship Between Transportation Demand and Supply: Granger-Causality Test Using Time-Series Data
    (Pamukkale Üniversitesi, 2022) Duvarcı, Yavuz; Duran, Hasan Engin
    Transport demand and supply are deemed to determine each other in a cyclic manner. The major idea has been that the demand is usually the preceding one. However, in urban cases, usually the land use variables in place of supply interfere this process. Cleansing the land use variables, the regional/national level variable pairs of demand and supply are employed to analyze the cause-effect mechanism. For objectivity, the Granger-causality test (GCT) is used to understand the relationship between transportation demand and supply. The Analyses were made at four dimensions; (a)whether the nexus is one-directional or bi-directional, (b)its significance level, (c)whether demand or supply is the preceding, (d)whether the effects are short-term or long-term. Using the Turkish statistics, the GCT results showed that, in the short/medium run, overwhelmingly the supply variables preceded (mostly in railway mode), mostly unidirectional (one-way causality) manner, however, in the long-run almost no relationship was found. In other transportation modes, no significant relationship is observed. Finally, bi-directional relations were usually observed in suburban rail. The investments then should be made according to known demand. Usually, the effects of supply (especially of railways and roadways) could rather fade away in the long-run. Still, no general statement can be made for the demand/supply causality especially in terms of which one is preceding and of the direction of causality. The chaotic nature of the process reigns over with the changing conditions.
  • Article
    Determining Scenario Based Highway Routes Using Geographic Information Systems; a Case Study of Simav-Kutahya Routes, Turkey
    (Pamukkale Üniversitesi, 2014) Erdem, Umut
    Transportation planning requires more efforts from city planners to use rational techniques to determine optimum road routes. To fulfill this requirement, this study aims at generating the cheapest and the shortest scenario based routes using Geographic Information Systems (GIS) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Digital Elevation Model (DEM) with Least Cost Path analysis between the Simav and the Kutahya cities, and comparing them with existing routes. For generating the shortest and the cheapest route, these cities are selected as sample since the study region is located in the transition area between central Anatolia and Aegean Region which has access to the sea and regional ports. The methodology used in this study is composed of three parts: first part consists of two steps; (i) generating the factors and (ii) determining scenarios focusing on different transportation themes that are used in the study process. In second part all factors are weighed regarding scenarios. In the third part of the study the outputs Path A (cheapest) and Path B (shortest) are generated by Least Cost Path analysis. The output routes were compared not only with each other, but also with the existing routes in terms of the generated factors.