In an analysis of the costs of sprawl in Canada, Walker and Rees used a metric called the

 ecological footprint  that converts, for comparative purposes, all energy, materials, and other resources

associated with different built environments into equivalent land area requirements. The authors found lot

size to be a very important factor in the analysis because lot size determines house frontage, which in

turn dictates the length requirements for infrastructure such as local streets and electricity, communica 

tions, and water and sewage lines.

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Walker and Rees's study also provides a breakdown of the resource requirements of these differ 

ent dwelling types. It indicates that only 53 percent of the ecological footprint of a detached house is

related directly to the type of housing, while 44 percent is related to its associated travel requirements,

with an additional 3 percent associated with the need for municipal infrastructure. This finding corre 

sponds quite well with a recent Finnish study on the effects of urban form on GHG emissions a continu 

ation of that country's urban sprawl is compared with a 30 year scenario based on locating new housing

much closer to employment and regional activity centers.

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The study suggests that 48 percent of the

reduction in GHG emissions from this more compact spatial development would come from efficiencies

brought about by district heating of residential and service buildings, another 48 percent would come

from reduced passenger travel within each commuting region, and an additional 4 percent savings would

be due to a reduced need for supporting municipal infrastructures. 

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B. Possible Policy Instruments

Policy actions that have been proposed to curtail the worst effects of

sprawl encompass a variety of  smart growth  initiatives.

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These initiatives

include land use zoning ordinances to encourage higher density, mixed use (residential, commercial,

recreational, light industrial) land developments; promotion of urban designs based on gridded street

plans and other compact and readily accessible local street systems; the provision of more pedestrian and

cyclist friendly pathways;

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and the use of green areas such as small urban parks and tree lined streets

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to act as carbon sinks and to help break up the well documented  heat island  effect that often accom 

panies asphalt, concrete, and other heat absorbing surfaces.

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Efforts to impact the future form of entire

metropolitan areas include the application of urban growth boundaries, as well as the use of financial

incentives to build housing subdivisions or employment centers at infill sites within the urban boundary.

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Both of these approaches limit the common practice of  leap frog  development that leads to the

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Towards a Climate Friendly  

Built Environment

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