Associate Professor Michael Buxton, RMIT University
Buxton M 2006, ‘Urban form and urban efficiency’ paper prepared for the 2006 Australian State
of the Environment Committee, Department of the Environment and Heritage, Canberra,
Many Australian State governments recently have developed land use policies which attempt to
alter urban form to gain greater urban efficiency. All these strategic plans share the same
commitment to more compact cities through higher density, mixed use, transit oriented
development in activity centres, improved public transport and limits on outer urban growth. All
share similar implementation problems, in particular, a reluctance to require compliance with
clear compact city policies.
Urban efficiency is usually defined in terms of travel patterns, infrastructure and energy use, and
social and environmental costs including water use, congestion costs and the costs of sprawl.
Societies which consume less land for urban purposes use roads less, infrastructure more
efficiently and can transfer more investment to productive sources. Better urban design reduces
social costs by increasing social cohesion. Cities function less efficiently as they expand and
reduce their average population density.
Changing components of urban form, such as density, can improve the efficient functioning of
cities and their environmental performance, although the interaction among variables is complex
and caution is needed in drawing detailed causal conclusions. McGlynn et al. (1991) showed that
three compact city models reduced growth in energy consumption and saved between $2.1 billion
to $4.2 billion in non transport infrastructure compared with a policy of urban expansion on city
fringes. As dwelling density increases, transport energy use (Owens 1986, Royal Commission
1994), transport emissions (ECOTEC Research and Consulting Ltd et al. 1993), and travel
distance (Rickaby 1987, Giuliano and Narayan 2003) falls. Mixed use centres contain
environmental, travel and cost efficiencies particularly through their impacts on trip frequency
and mode choice (Banister 1992, Loder and Bayly et al. 1995, Ewing and Cervero 2001).