Analysis of Changing Accessibility Indicator in Metropolitan of Sydney (1991-2001)

One of the most important matters for enhancing environmental quality especially in urban environment is developing accessibility versus mobility. Because the result of this transition from mobility especially personal car mobility to community accessibility (public transportation) reduce length of trips, consumption of energy and finally less air and environment pollution. Therefore, appropriate accessibility is a necessary element for achieving sustainability in urban environment.With regard to this matter, we calculated accessibility indicator by zonal opportunity gravity model (employed person and spatial distance between zones) for 38 local government boundaries (zones) with complementary GIS tools. Moreover, changing of accessibility measured during 1991-2001. Also relation between accessibility index and six sub Social-economical-physical group factors (14 variables) was calculated by using multiple regressing and coefficient of correlation with SPSS software. Results show that accessibility value decreased by distance from city center to peripheral areas of Sydney. Also result yielded from map of accessibility changes show that two phenomena had taken place stimulatingly. One is high positive change of accessibility value both in central core mostly strap pattern (concentration) and sub-urban areas (decentralization), the other on is negative change of accessibility value in the middle rings of Sydney. Also results of calculating relation between accessibility index and social-economical and physical variables show that zones by low car usage to work, high public transportation facilities and so on have high accessibility value. In contrast, zones with low weekly income family, far from city center, high percentage of car usage to work, big household size and low public transportation facilities have low accessibility value.