The impacts of the residential location on transport energy use: a case study from Ankara

Efficient use of energy is one of the key elements of sustainability. Energy consumption through transport has been increasing, not because transport has become less energy efficient but rather because the overall travel demand has been increasing so rapidly. An increasing number of trips by motorised modes as well as increasing travel distance are two main indicators of this trend. In order to lower the energy used by transport, consideration must be given not only to the policies directly related to transport, but also to those related to urban development. It may be possible to reduce the amount of energy use in an urban environment through these policies. Thus, one of the objectives of planning activity is the realisation of cities which promote short distance trips with more energy efficient transport modes. The main concern of this research is to examine the possibilities of having more energy efficient travel demand patterns and to find out under what circumstances, the spatial structure of an urban area allows for a reduction in the energy used by transport. Urban residential developments that tend to move out of the city are especially good example of development that might result in more energy intensive travel demand patterns. In terms of its relation both to the inner city and in itself, the overall travel demand characteristics of a city can easily be changed by residential choice. New housing developments, especially the out-of-city ones, may lead residents either to travel for longer distances, or to use cars widely, or both. But, it could stimulate them to travel for shorter distances or to use motorised modes less, or both. The spatial structure of a new development and its connection and relation to other facilities (such as work places, schools, shopping areas, recreational places and so forth), shape travel demand patterns. This research has attempted to define the travel demand patterns of the inner and out-of city residents of Ankara and to discuss the factors affecting them. Beside this comparative analysis, there was an attempt to discover what the out-of city residents would do if they were living in the inner city districts. The possibilities of having more energy efficient travel demand patterns in the selected districts of Ankara were examined. It is evident from the survey results that transport energy use changes due to the location of a residence relative to the CBD. Living in an out-of city area means travelling for longer distances and a wider use of motorised modes. Living near to the central facilities encourages walking trips. Trips by motorised modes also have a considerable share, but the travel distance is not as long as in the out-of city case. Additionally, dependence on cars has been accelerating through the increasing distance of residence from the central inner city facilities. Following the assumption that the previous residence of out-of city residents was the inner city, the comparison of previous and actual travel demand patterns indicates that they used to have less energy intensive travel demand patterns. The main reason behind the urban decentralisation policy was to reduce the air pollution level in Ankara. Research findings, however, confirms that increasing travel demand together with transport energy consumption are negative outcomes of this policy. These developments are contributing the environmental problems through wider use of motorised modes and long distance trips and air pollution created by huge volume of traffic coming into the inner city. Thus, it is out of question whether the planning objectives have been reached or not through the urban decentralisation measures or what should be the additional measures or policies to contribute sustainable urban development process