In 1993, Portland, Oregon became the first U.S. city to adopt a plan to address global warming, intended to reduce emissions to 10% below 1990 levels by 2010. New transit investments and continued improvements to bicycling and walking infrastructure have thus far resulted in per capita CO2 emissions reductions of 12.5 percent. Ultimately, Portland’s complete streets and associated land use policies yield carbon savings worth between $28 and $70 million annually.
Incomplete streets will hamper climate change strategies
The transportation sector is the fastest growing carbon dioxide source in the United States with emission rates rising 2% per year. Projections show that more efficient fuels and ‘clean’ vehicles won’t be enough to offset the projected 59 percent increase in driving between now and 2030. Even with expected improvements in vehicle and fuel economy, carbon emissions from transportation would be 41 percent above today’s levels by 2030 if driving is not curbed .
The IPCC recommends modal shifts from driving to walking, bicycling, and transit as a key mitigation strategy. Yet the transportation infrastructure in the United States is not diverse enough to accommodate an increase in pedestrians, bicyclists, and transit users. Many trips are made by automobile because of incomplete streets that make it dangerous or unpleasant to walk, bicycle, or take transit. In fact, a national survey found that bike lanes were available for less than five percent of bicycle trips, and more than one-quarter of pedestrian trips were taking place on roads with neither sidewalks nor shoulders . Other surveys have found that a lack of sidewalks and safe places to bike are a primary reason people give when asked why they don’t walk or bicycle more. For example, a recent survey of Florida residents found only 25 percent felt it was safe to walk along or to cross the closest U.S. or State road.
Streets need to be completed to include places for people to walk, bicycle, and safely reach transit stops.
The climate-cooling potential of Complete Streets
Walking and bicycling are zero-emission transportation modes, and transit is a lower-emissions mode – using transit can help a solo commuter who switches from driving to transit to reduce carbon dioxide emissions by 20 pounds per day, or more than 4,800 pounds in a year .
Complete Streets are essential in order to make it possible for Americans to drive less and use our streets to get around more easily on foot, bike, and public transit. The potential to shift trips to lower-carbon modes is undeniable: The 2001 National Household Transportation Survey finds that 50% of all trips in metropolitan areas are three miles or less and 28% of all metropolitan trips are one mile or less – distances easily traversed by foot or bicycle. Yet 65 percent of trips under one mile are now made by automobile , in part because of incomplete streets that make it dangerous or unpleasant to walk, bicycle, or take transit. Complete streets would help convert many of these short automobile trips to multi-modal travel. Other studies have calculated that 5-10% of urban automobile trips can reasonably be shifted to non-motorized transport .
Places that are giving people options are seeing a reduction in their emissions. Boulder, Colorado is working to create a complete street network, with over 350 miles of dedicated bike facilities, paved shoulders and a comprehensive transit network. Between 1990 and 2003, fewer people in the city drove alone, more people bicycled, and transit trips grew by a staggering 500 percent. The reduction in car trips has cut annual CO2 emissions by half a million pounds .
Complete streets policies aren’t just a worthy end in the themselves. They’re also an important means to help reduce heat-trapping pollution and should be an element of every jurisdiction’s climate change toolbox.
[all fact sheet citations are available in the downloadable files]
Additional Resources:
Moving Cooler: An Analysis of Transportation Strategies for Reducing Greenhouse Gas Emissions
Urban Land Institute, 2009
Driving and the Built Environment: The Effects of Compact Development on Motorized Travel, Energy Use, and CO2 Emissions
Transportation Research Board, 2009
Public health benefits of strategies to reduce greenhouse-gas emissions: urban land transport
James Woodcock, Phil Edwards, Cathryn Tonne et al., 2009
Active Transportation for America
Rails-to-Trails Conservancy, 2008
The Broader Connection between Public Transportation, Energy Conservation and Greenhouse Gas Reduction (.pdf)
ICF International, 2008
Endangerment and Cause or Contribute Findings for Greenhouse Gases under the Clean Air Act
U.S. Environmental Protection Agency
Growing Cooler: The Evidence on Urban Development and Climate Change
Urban Land Institute and Smart Growth America, 2007
Portland’s Green Dividend
Joe Cortright, CEOs for Cities, 2007
Modal Shift in the Boulder Valley 1990-2006 (.pdf)
National Research Center Inc. for the City of Boulder, Colorado, 2007
Intergovernmental Panel on Climate Change 2007: Summary for Policymakers (.pdf)
Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change
Public Attitude Survey of Bicycle and Pedestrian Planning (.pdf)
Wilbur Smith Associates, 2007
Public Transportation’s Contribution to U.S. Greenhouse Gas Reduction (.pdf)
Todd Davis and Monica Hale, SAIC, 2007
City of Portland Local Action Plan on Global Warming: 2005 Progress Report (.pdf)
City of Portland, Office of Sustainable Development, 2005
Exercise-based Transportation Reduces Oil Dependence, Carbon Emissions and Obesity
Environmental Conservation, 2005
Statewide Survey on Bicycle and Pedestrian Facilities (.pdf)
Center for Urban Transportation Research at the University of South Florida for the Florida Department of Transportation, 2005
