A. Estimates of GHG Reduction Potentials
Well planned compact growth consumes 45 percent less land and costs
25 percent less for roads, 20 percent less for utilities, and 5 percent less for
schools, than does sprawling growth.
One study found a direct relationship between the
number of dwellings per acre and the level of GHGs released. At a fairly common suburban density of four
homes per acre, CO
emissions per household were estimated to be 25 percent higher than in an urban
neighborhood with 20 homes per acre.
Figure 12 shows the hypothesized impact of residential density on
travel related CO
Locational efficiency research by Holtzclaw and coauthors, based on detailed spatial data for the
San Francisco Bay Area, Los Angeles, and Chicago, found energy efficiency to be highly correlated with
per acre residential density,
with public transit service
Affects Travel Related
density within walking
distance of the house, with
household income, and
with household size.
concluded that differences in
density and access to public
transit are significant predic
tors of per household vehicle
miles of travel. Burer and
emissions per household (lbs/year)
coauthors show that higher
residential and employment
densities, mixed land use,
Source: Computed using the San Francisco League of Conservation Voters calculator,
and job housing balance are
associated with shorter trips
and lower automobile ownership and use.
The most recent set of U.S. based locational efficiency
studies project considerable potential for GHG reductions, with savings on the order of 10 percent of the
2001 level of GHGs produced in the United States suggested as possible within as few as 10 years.
Towards a Climate Friendly