A Calculation Method and Its Application of Bus Isochrones

Bus isochrones indicate the maximum scale of bus system can extend during one time interval. A calculation method of isochrones is proposed in this paper and it can be applied to the analysis of public transport accessibility. The travel process by bus is analyzed and divided into five parts: walking to the bus stop from departure, waiting for buses, boarding buses, transfer and walking to the destination. Specific calculation methods of time cost are proposed for each part, respectively. Then, the isochrones are by the grid method and the inverse distance weighting method. The bus GPS data of Guangzhou, China is used to draw the isochrones maps and to demonstrate the Tee mall. Furthermore, the space-time accessibility is measured in the covering area of a unit time isochrones and the accessibility differences of different directions are then analyzed through profiles.