Washington, D.C. – Increasing population and employment density in metropolitan areas could reduce vehicle travel, fuel use and CO2 emissions, according to a new report by the U.S. National Research Council (NRC). The study found that CO2 emissions could be reduced from less than one per cent up to 11 per cent by 2050, compared to a base case for household vehicle use.
Assuming compact development is focused on new and replacement housing, since converting existing housing to higher densities could be prohibitively difficult, significant increases in density would result in modest short-term reductions in personal travel, energy use and CO2 emissions, with reductions growing over time.
Currently, 80 per cent of Americans live in metropolitan areas, but population and employment are increasingly decentralized. This trend of suburbanization, made possible largely due to automobiles and extensive highway systems, reflects the preferences of many Americans for living in detached, single-family homes. Compact, mixed-used development, with individuals living in denser environments with jobs and shopping close by, could reduce the number of vehicle miles travelled by shortening trips, and by making walking, biking and public transit more viable alternatives, according to the report.
The most reliable research studies estimate that doubling residential density in a metropolitan area might lower household driving between five and 12 per cent. If higher density were paired with more concentrated employment and commercial locations, and combined with improvements to public transit and other strategies, household driving could be lowered by as much as 25 per cent.