The growing demand for conveniently located housing in walkable, accessible, compact neighborhoods with a mix of uses has been well-documented, but according to research released today, meeting that demand could significantly reduce the growth in the number of miles Americans drive, shrinking the nation’s carbon footprint while giving people more housing choices.
In Growing Cooler: The Evidence on Urban Development and Climate Change, a comprehensive review of dozens of studies, published by the Urban Land Institute, the researchers conclude that urban development is both a key contributor to climate change and an essential factor in combating it.
They warn that if sprawling development continues to fuel growth in driving, the projected 59 percent increase in the total miles driven between 2005 and 2030 will overwhelm expected gains from vehicle efficiency and low-carbon fuels. Even with projected efficiency improvements, vehicle emissions of carbon dioxide would be 41 percent above today’s levels, rather than well below 1990 levels as required for climate stabilization by 2050, according to Growing Cooler.
“Curbing emissions from cars depends on a three-legged stool: improved vehicle efficiency, cleaner fuels, and a reduction in driving,” said lead author Reid Ewing, Research Professor at the National Center for Smart Growth, University of Maryland. “The research shows that one of the best ways to reduce vehicle travel is to build places where people can accomplish more with less driving.”
Depending on several factors, from mix of land uses to pedestrian-friendly design, compact development reduces driving from 20 to 40 percent, and more in some instances, according to the authors. Typically, Americans living in compact urban neighborhoods where cars are not the only transportation option drive a third fewer miles than those in automobile-oriented suburbs, the researchers found.
At the same time, the book documents market research showing a majority of future housing demand lies in smaller homes and lots, townhouses, and condominiums in neighborhoods where jobs and activities are close at hand. The researchers note that demographic changes, shrinking households, rising gas prices, lengthening commutes and cultural shifts all play a role in that demand.
The report cites real estate projections showing that two-thirds of development expected to be on the ground in 2050 is not yet built, meaning that the potential for change is profound. The authors calculate that shifting 60 percent of new growth to compact patterns would save 85 million metric tons of CO2 annually by 2030. The savings over that period equate to a 28 percent increase in federal vehicle efficiency standards by 2020 (to 32 mpg), comparable to proposals now being debated in Congress.
“Clearly, the development industry has a key role in the search for solutions to offset the impact of climate change,” said ULI Senior Resident Fellow William H. Hudnut, III, former mayor of Indianapolis. “Whether close-in or in suburbs, well-planned communities give residents the option to walk, bike or take transit to nearby shopping, retail and entertainment. Being able to spend less time behind the wheel will benefit our health, our pocketbooks and the environment.”
Implementing the policies recommended in the report would reverse a decades-long trend. Since 1980, the number of miles Americans drive has grown three times faster than population, and almost twice as fast as vehicle registrations. Spread-out development is the key factor in that rate of growth, the research team found.
The findings show that people who move into compact, “green neighborhoods” are making as big a contribution to fighting global warming as those who buy the most efficient hybrid vehicles, but remain in car-dependent areas.
While demand for such smart-growth development is growing, government regulations, government spending, and transportation policies still favor sprawling, automobile-dependent development. The book recommends changes in all three areas to make green neighborhoods more available and more affordable. It also calls for including smart-growth strategies as a fundamental tenet in upcoming climate change legislation.
The study represents a collaboration among leading urban planning researchers, including Ewing, Keith Bartholomew at the University of Utah, Jerry Walters of Fehr and Peers Associates, Steve Winkelman of the Center for Clean Air Policy and the Urban Land Institute. Smart Growth America coordinated the multi-disciplinary team that developed the recommended policy actions and is leading a broad coalition to develop those strategies further.