1、Primer on Transportation and Climate Change April 2008Climate Change, VMT, and the Economy: The AASHTO Perspective I n its July 2007 publication, A New Vision for the 21st Century, AASHTO noted that “global climate change has become a political, environmental, and economic fact of life.” That report
2、 identified bold but achievable goals for reducing Greenhouse gas (GHG) emissions from road transportation: Support the Presidents goal to reduce oil consumption 20 percent in 10 years. Double the fuel efficiency of passenger cars and light trucks. Double transit ridership by 2030, and significantly
3、 expand the market share of passengers and freight moved by rail. Reduce the growth in vehicle miles traveled (VMT)from three trillion in 2006 to five trillion, rather than the projected seven trillion, by 2055. Increase the percentage of those who car pool, walk, bike, or work at home. Achieving th
4、ese goals will require major efforts to develop next-generation technologies in vehicles and fuels. Current government forecasts assume only incremental advances in vehicles and fuels between now and 2020, with few additional gains beyond that year. Much greater improvements will be needed in order
5、to achieve major reductions in GHG emissions. In addition to improving vehicles and fuels, it also will be important to reduce the growth in VMT as com- pared to recent trends. Between 1982 and 2007, VMT grew at approximate 2.5 percent annuallyclosely tracking growth in the economy and personal inco
6、me, and exceeding the growth in population. Going for- ward, some growth in VMT will be needed to accommodate a growing population and a growing economy, including truck freight shipments. Therefore, rather than seeking to cut VMT in real terms, AASHTO has proposed a goal of reducing the rate of gro
7、wth in VMT to approximately the rate of population growthabout 1 percent per year. It was interesting to note how the United Kingdom addressed this issue in its October 2007 report To- ward a Sustainable Transport System. The report found that for transport, supporting economic growth and tackling c
8、arbon emissions, “does not have to be an either/or choice.” Likewise, AASHTO believes U.S. policies must be balanced in ways which help reduce transportations impact on global climate change, but which also sustain VMT growth at the level needed to support a healthy National economy. John Horsley Ex
9、ecutive Director 2008 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law. 2008 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of appli
10、cable law.iii Introduction 1 Executive Summary 3 Part I: The Causes and Impacts of Climate Change 7 The Evidence of Climate Change .7 The Impacts of Climate Change on the Transportation System 8 The Causes of Climate Change 10 Increasing GHG Emissions .10 Reducing Carbon Absorption .12 Part II: Clim
11、ate Change and Public Policy 15 The Goals of Climate Change Policy 15 Stabilizing Global Average Temperatures .16 Stabilizing GHG Concentrations in the Atmosphere .16 Reducing GHG Emissions .16 Increasing Carbon Absorption .17 Adaptation .18 Potential Strategies for Reducing GHG Emissions in the Uni
12、ted States 19 Establishing a “Carbon Price” 19 Other Strategies to Promote GHG Emission Reductions .20 Part III: Trends in GHG Emissions from Road Travel .23 Data Sources 23 Current Government Forecasts 25 Trends in Fuel Economy .25 Trends in Use of Alternative Fuels .25 Trends in VMT 27 Trends in G
13、HG Emissions .28 Alternative Forecasts: The Potential for Faster Reductions 28 Four Alternate Scenarios .29 Results .29 Contents 2008 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.Part IV. How Do We Get Th
14、ere from Here? 33 Technological Innovations in Vehicles and Fuels.33 Gas/Electric Hybrids 33 Plug-In Hybrids .33 Biofuels 34 Hydrogen Fuel-Cell Vehicles 35 Reducing the Growth in VMT.36 Expanding Transit Service 36 Other Alternatives to Single-Occupant Auto Travel 37 Changes in Land-Use Patterns .37
15、 Operational Strategies .39 Congestion Relief .39 Driver Behavior 40 The Policy Toolbox 40 R summarizes the impacts of climate change, including impacts on the transportation system; and explains how greenhouse gas emissions con- tribute to climate change. Part II provides an introduction to climate
16、 change pol- icy issues. This section briefly outlines the main goals of climate change policies, and provides an overview of the major strategies that are being considered and/or adopted to achieve those goals. This section includes a discussion of “cap and trade” proposals, a carbon tax, energy ef
17、fi- ciency standards, and other economy-wide proposals that could be adopted to address climate change. Part III discusses trends in GHG emissions from road transportation. This section reviews historical trends and current government projections for fuel economy, vehi- cle miles traveled (VMT), and
18、 greenhouse gas emissions from road transportation. It also presents four alternate scenarios showing that faster improvements in fuel econ- omy and somewhat slower growth in VMT could result in steep reductions in greenhouse gas emissions by 2050. Part IV reviews potential measures to reduce GHG em
19、issions from road transportation. This section dis- cusses potential improvements in vehicles and fuels; potential ways to reduce the growth of VMT; and potential operational strategies for reducing GHG emissions. This section then provides an overview of policy tools that could help promote these c
20、hanges, including measures such as increasing fuel economy standards; requiring greater use of renewable fuels; expanding funding for research and development; and establishing a “carbon price” through a cap-and- trade system or other measures. Part V identifies issues for further research. This sec
21、tion lists a series of issues that warrant additional research by AASHTO or others. For example, one important issue is the underlying growth trend in VMT . There is some evidence that growth in VMT is slowing due to economic and demographic factors. Additional research is needed to ensure that poli
22、cymakers have a solid basis for setting policies on transportation and climate change. The Reference Materials section, which follows Part V, includes a list of major studies and other published reports on climate change and transportation. A litera- ture review summarizing these reports has been po
23、sted on the AASHTO web site along with this primer at bookstore.transportation.org. This primer is based on the most recent research in the field. Its purpose is to outline the current thinking of gov- ernmental agencies, researchers, and advocacy groups on the issue of climate change and transporta
24、tion. The con- clusions stated in those reports do not necessarily reflect the views of AASHTO or its members. AASHTO will be sponsoring additional research and will be providing the results of that research in subsequent reports. Introduction Cover photo courtesy of FIGG, engineer of record for the
25、 Natchez Trace Parkway Arches. 2008 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law. 2008 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a viol
26、ation of applicable law.3 A uthoritative sources tell us the global cli- mate is becoming warmer. Global warming is caused in large part by human activities. If allowed to continue unchecked, it will cause severe and lasting impacts. What is the role of transporta- tion in mitigating global climate
27、change and adjust- ing for its impacts? Anticipated Impacts Affecting Transportation Research studies have identied the serious impacts climate change poses for transportation. Increases in very hot days will increase the frequency of wildres, compromise pavement integrity, and deform rail lines; in
28、creased ooding of coastal areas will inundate roads, bridges, and rail lines; increases in Arctic temperatures will cause subsidence of permafrost, disrupting roads, rail lines, and airports. Heavier rainfall in many parts of the country will require redesign and replacement of drainage structures;
29、and more frequent and more severe hurricanes will disrupt service in aected areas and require devoting more resources to evacuations. Recent Reports Say Climate Change Poses a Big Problem for Transportation Recent authoritative reports have conrmed the chal- lenges that global climate change will po
30、se for the trans- portation sector. These studies include the 2007 Report of the Intergovernmental Panel on Climate Change and TRBs Report 290: Potential Impacts of Climate Change on U.S. Transportation, 2008. Emission of Greenhouse Gases Is Causing Temperatures to Rise e strategy to stop the contin
31、uing rise in tempera- tures is to slow down the rate of greenhouse gas (GHG) emissions and ultimately stabilize GHG concentra- tions in the atmosphere. e goals of climate change policy are to stabilize glob- al average temperatures and prepare for the impacts of climate change. U.S. Goals for Greenh
32、ouse Gas Emission Reduction To date, the U.S. government has not adopted a specic GHG reduction goal. e U.S. Climate Ac- tion Partnership (U.S. CAP)a broad coalition of industry and environmental groupshas set a goal to reduce U.S. GHG emissions below 2005 levels by 6080 percent by 2050. Many states
33、 have ad- opted even more aggressive goals. Cap-and-Trade or Carbon Tax Many economists have agreed that the most cost-ef- fective way to reduce GHG emissions is to establish a carbon price. Carbon pricing would give business- es and individuals an incentive to use less carbon. A carbon price could
34、be set by establishing a cap- and-trade program or a carbon tax. Under a cap- and-trade program, allowances for emissions would be allocated by the government, possibly through an auction. e price of emitting carbon and other greenhouse gases would be increased to the point a Executive Summary 2008
35、by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law. given industry would reduce them directly or by purchasing allowances from others. Imposing a carbon tax would have a similar effect. Cap-and-trade appears to
36、 be the solution which stands the best chance of near- term enactment in Congress. Climate Change and Transportation It is estimated that approximately 33 percent of GHG emissions in the United States come from transporta- tion. Seventy-two percent of the transportation sectors emissions are generat
37、ed by road use. Factors Affecting Road-Related GHG Emissions There are several factors that affect the GHG emis- sions from road transportation. These include: 1) fuel economy, 2) the type of fuel used, and 3) the number of vehicle miles traveled. A fourth is traffic operations, including traffic-fl
38、ow management by transportation agencies and individual driving behavior. Fuel Economy In 2007, Congress enacted fuel economy standards that will require that the average of all new vehicles in the light-duty automotive fleet, which includes cars, light trucks, and sports utility vehicles, achieve a
39、 standard of 35 miles per gallon by 2020. The average today for both new and existing vehicles is approximately 20 mpg, so this will bring about a major change in the vehicles pro- duced and sold by the auto industry. Alternative Fuels and Hybrid Vehicles It is hoped that alternative fuels, such as
40、ethanol and biodiesel, will help reduce GHG emissions because they emit less CO 2for each unit of energy produced. There is also interest in the contribution that hybrids, plug-in electric, and hydrogen-fueled vehicles can make in the future. Alternative fuels represent less than two percent of the
41、fuel supply in 2006, and DOE projects that they will rise to only eight percent by 2030. GasElectric Hybrids. A good example of the po- tential of hybrid vehicles is the Prius, which is rated at 46 mpg in average fuel efficiency, as compared to a standard T oyota vehicle, the Corolla, which is rated
42、 at 27 mpg city and 35 mpg highway. Plug-In Electric Hybrids. Plug-in electric hy- brid vehicles are being developed. Many of them are expected to achieve fuel efficiency rates of 100 mpg. According to DOE, their commer- cial deployment is not expected to occur until around 2015. Biofuels. Federal a
43、nd state laws have promoted increased use of ethanol and other biofuels as an energy supply for transportation vehicles. For ex- ample, in 2007 Congress enacted energy legislation mandating the production of 36 billion gallons of biofuels by 2020. While most current biofuels come from corn, there is
44、 great interest in the de- velopment of cellulosic ethanol, which is expected to represent a more clear-cut reduction in GHG emissions. Zero-Emission Vehicles, Like Hydrogen. Also under development are hydrogen fuel-cell pow- ered vehicles which produce zero GHG emissions from the vehicle itself. (E
45、nergy is required to pro- duce the hydrogen fuel supply for the vehicles; if fossil fuels are used to produce the hydrogen, then there will be some GHG emissions associ- ated with the use of hydrogen-powered vehicles.) Hydrogen-powered vehicles are unlikely to be- come widespread by 2030, but they c
46、ould become more widely used between 2030 and 2050. Strategies to Reduce Growth in VMT. There is great interest in policies to reduce the growth of highway demand by shifting trips to other modes of travel. AASHTO, for example, supports a policy to double transit ridership by 2030. There is hope tha
47、t making more trips by biking, walking, and telecom- muting could help reduce GHG emissions as well. Potential of Transit and Land Use. Many hope that increased transit usage can result in a net re- duction in GHG emissions. What is not clear is to what extent. Research done for the Pew Center for G
48、lobal Climate Change found that, “reducing emissions via increased use of transit would require momentous efforts as transit accounts for only one percent of passenger-miles traveled in the United States today.” A recent report, published by several smart growth advocacy groups concluded that the combination of aggressive land-use strategies and 2008 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.
