Why is urban sprawl bad?

Suggestions that high density living is more environmentally sustainable don’t concur with the evidence. No less than the Australian Conservation Foundation showed (in its Consumption Atlas) that residents of inner city, high density housing created a larger carbon footprint through energy use than suburban alternatives. They also showed that inner city residents were generally no more likely to use public transport than suburban alternatives. The reason? They’re wealthier, with less need to turn off the lights and conserve power.

This was reinforced in studies by Professor Bob Birrell of Monash University, who showed that high density dwellings were typically more energy intensive. Stands to reason if you think about it: lighting and air conditioning of common areas, lack of cross flow ventilation, use of electric clothes driers rather than a (solar) clothes line in the backyard. The list goes on.

Additional studies by Professor Kevin O’Connor, Professorial Fellow of the Architecture, Building and Planning School and the University of Melbourne suggested that suburban locations with treed footpaths and vegetated backyards actually provide more “green” space and leaf cover than high or medium density housing can. Pot plants on the verandah don’t quite cut it.

The suggestion that more high density will mean more open space is counter intuitive. We are not opening more public parks in inner city or middle ring neighbourhoods. More density will invariably mean more people wanting to use the existing open space. That in itself may not be a bad thing but in high density cities (and I grew up in one in Hong Kong) available open space is more crowded. Kicking a football or playing cricket in the community park might become a thing of the past the moment some jogger gets clocked on the noggin from a good drive to deep cover.

The suggestion that high density housing will mean that people won’t need cars is also not supported by the available evidence. An interesting paper by Paul Rees of RMIT suggests that the nexus between urban density and types of transport “show little or no relationship to transport modes share, which seems more closely related to different transport policies. These findings are very different from those on which current urban policies are based, and suggest the need for a radical rethinking of those policies.” You can read the paper here (PDF 126KB). It’s called evidence, don’t worry, it might be unfamiliar but it won’t hurt you.

A similar conclusion was reached by David McClockey, Professor Birrell and Rose Yip in a paper entitled “Making public transport work in Melbourne” published in People and Place which you can read online here. In it, they concluded that the proportion of residents living in TOD style (Transit Oriented Development) housing only rose as TOD locations were closer to the city, where (ironically) people are wealthier. And even then, public transport rates of use were not that much higher than in alternative locations.

A final nail in this ideological coffin is the obvious: between and eight and nine out of every ten jobs are in the suburbs. Nurses, teachers, tradies, shop workers, industrial workers, suburban professionals - all located in suburban commercial centres which are not serviced by public transport. You could find yourself living in an inner city TOD and still be reliant on your car because your place of work is not in the CBD, or for other reasons of convenience (e.g. the children aren’t in a CBD school). Even a heroic public transport assumption of 30 per cent public transport use in high density areas (triple current rates) would mean that 70 per cent of high density housing residents will still use their cars. And that will inevitably mean more cars on existing road space, not less.

So the truth is being crushed by the anti density zealots on one side and pro-density zealots on the other, while the evidence itself is infrequently consulted, if at all.

There are very good reasons why planned new suburban communities, if done well, can achieve the environmental, social, community and economic benefits claimed for high density housing. There are also very good reasons why higher density, if done well, can become an asset for the community and build a better city. Witness the quality of urban form outcomes in Brisbane’s New Farm and Teneriffe areas, achieved under the watch of Trevor Reddacliff and his Urban Renewal Task Force.

But in doing so, it’s worth recalling that Trevor fought vehemently against proposals for 20 and 30 storey towers throughout the area. And thank goodness he did - the picture today of the New Farm-Teneriffe area would be ghastly had he not. Trevor also didn’t fall for slogans or policy dogma. He was a pragmatist who valued good urban design and relied on evidence.

I wonder what Trevor would make of this debate were he still alive today?