The disadvantages of the low-density car-based suburbs that now surround Australian cities are widely debated. These include facilities located to the disadvantage of non-car users, wasteful use of land, cost of infrastructure, time and energy expended on driving, low incidence of social contact and lack of exercise. Many Australians now choose to live in or near to the centres of cities and there is encouragement from planning policies and property market pressures for comparatively higher density living. Nevertheless, older Australian suburbs also have compensating advantages for both the residents and the wider community. Many are comparatively near to city centres and were built around a reasonable level of public transport access, especially by train. The presence of soft landscaping around the house provides a positive environmental advantage for the community as a whole. The presence of trees provides shade: modifying the microclimate and giving aesthetic pleasure. There is a generally high degree of biodiversity. The planted areas also aid the process of storm drainage by retaining water and reducing run-off. Indeed, open space is synonymous with the traditional image of suburbia.