Each location in the model, with the exception of public transport, has an x -y coordinate assigned to it on a 10 Â 10 square grid. Inhabitants of the city move from one location to the next according to their individual schedules. Commuting between grids is done by either private (i.e. cars) or public transport. However, between locations on the same grid coordinates, it is assumed that movement does not require any forms of transport. Public transport is considered as a location.