The planning of bus accessibility, due to the observing of social and economical matters and joining of urban land use and the transport system, has an essential position in the planning and designing process of the city. The importance of this matter has been highly recognized since the 1950's, especially after the criticism of the city designing model based on the Auto City, because it caused the horizontal expansion of the cities (sprawl), environmental pollution, separation of the work

more »

... and houses and increasing transport costs. The purpose of this research is to evaluate accessibility based on the bus system in the City of Mashhad, to determine the direct inaccessible regions for citizens to the bus system and also to determine the ideal radius accessibility and to design the best route for buses. To achieve this purpose the reformed Hansen and Pooler model was used (Hansen 1959 and Pooler 1995), which was based on population variables, occupation and by calculating the potential attraction and the distance between different municipal regions in Mashhad (12 regions) which was completed with the help of a Geographical Information System (GIS). The results of the usage of this model in Mashhad indicate that after personal transportation (27% of all trips), buses are the main use for public transportation with which 24% of all daily trips are made, 88% of the expansion and 86% of the citizens have direct accessibility to buses, meaning that 25,49 square kilometers and 342987 of citizens do not have direct accessibility to the bus system. Also the accessibility coefficient shows differences in different regions of the city. It shows an increase from the populated, low-income regions in the north-east towards the developing regions in the south-west and west of the city. Finally, creating new bus lines and changing the current ones, to cover the regions without direct accessibility to buses, is an effective step towards creating the sustainable development of the city.