[2] Intergovernmental Panel on Climate Change, Climate Change 2007: The Physical Science Basis, Summary for Policy Makers, 5 February 2007.

[3] P.J. Webster, et al., “Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment,” Science, 309(5742):1844-1846, 16 September 2005.

[4] Intergovernmental Panel on Climate Change, Climate Change 2007: Impacts, Adaptation and Vulnerability, Summary for Policymakers, 13 April 2007.

[5] California Environmental Protection Agency, Air Resources Board, Staff Report: Initial Statement of Reasons for Propose Rulemaking, Public Hearing to Consider  Adoption of Regulations to Control Greenhouse Gas Emissions from Motor Vehicles, 6 August 2004.

[6] Annual savings for each state except California were extracted from California Air Resources Board, Regulations to Control Greenhouse Gas Emissions From Motor Vehicles, Final Statement of Reasons, 4 August 2005. Cumulative savings for California were calculated using the average ratio of cumulative savings to 2020 savings in other states that will implement the program beginning in model year 2009.

[7] Estimated emission reductions come from three different analyses. For Northeastern states, we relied on an analysis conducted by the Northeast States for Coordinated Air Use Management (NESCAUM), as presented in Northeast State GHG Emission Reduction Potential from Adoption of the California Motor Vehicle GHG Standards, Summary of NESCAUM Analysis, October 2005. The California Air Resources Board included its estimate for California in Regulations to Control Greenhouse Gas Emissions From Motor Vehicles, Final Statement of Reasons, 4 August 2005. For Maryland, Oregon, Pennsylvania, and Washington, we calculated the emission reductions using the methodology described in Elizabeth Ridlington and Brad Heavner, Environment Maryland Research and Policy Center, Cars and Global Warming: Policy Options to Reduce Maryland’s Global Warming Pollution from Cars and Light Trucks, September 2006.

[8] U.S. Department of Energy, Energy Information Administration, International Energy Annual 2004, 19 July 2006.

[9] Based on 596 gallons of fuel per vehicle per year from U.S. Department of Transportation, Federal Highway Administration, Highway Statistics 2005, downloaded from www.fhwa.dot.gov/policy/ohim/hs05/pdf/nt6.pdf, 10 May 2007 and carbon dioxide emissions of 19.654 pounds per gallon of gasoline from U.S. Department of Energy, Energy Information Administration, Voluntary Reporting of Greenhouse Gases Program, Fuel and Energy Source Codes and Emission Coefficients, downloaded from www.eia.doe.gov/oiaf/1605/coefficients.html, 10 January 2006.

[10] Current transportation-related gasoline consumption in BTU from Energy Information Administration, State Energy Data System, 9 August 2006, was multiplied by a carbon coefficient as specified in Energy Information Administration, Documentation for Emissions of Greenhouse Gases in the United States 2003, May 2005.

[11] U.S. Energy Information Administrations, International Energy Annual 2004, 19 July 2006.

[12] Lower percentage reductions for some states are likely the result of methodological differences in the studies used to estimate the reductions, not reduced effectiveness of the program in those states. Estimated emission reductions come from two different methodologies. For Arizona, New Mexico and North Carolina, we relied on analyses conducted by the Center for Climate Strategies. Arizona data was from Center for Climate Strategies, Completed and Pending Policy Option Descriptions, prepared for 22 June 2006 meeting of Arizona Climate Change Advisory Group, and Center for Climate Strategies, Final Arizona Greenhouse Gas Inventory and Reference Case Projections, 1990-2020, approved by Arizona Climate Change Advisory Group March 2006. New Mexico data was from Center for Climate Strategies, New Mexico Climate Change Advisory Group, Final Report, December 2006. North Carolina data was from Center for Climate Strategies, Transportation and Land Use Technical Work Group, Summary List of Mitigation Options, prepared for 10 April 2007 meeting of Climate Action Plan Advisory Group Transportation and Land Use Technical Work Group, and Center for Climate Strategies, Revised Draft North Carolina Greenhouse Gas Inventory and Reference Case Projections 1990-2020, March 2006. For Colorado, Illinois and New Hampshire, we calculated the emission reductions using the methodology described in Elizabeth Ridlington and Brad Heavner, Environment Maryland Research and Policy Center, Cars and Global Warming: Policy Options to Reduce Maryland’s Global warming Pollution from Cars and Light Trucks, September 2006.

[13] Based on 2005 crude oil and oil product import figures from U.S. Department of Energy, Energy Information Administration, U.S. Total Crude Oil and Product Imports, by Country of Origin, downloaded from tonto.eia.doe.gov/dnav/pet/pet_move_impcus_a2_nus_ep00_im0_mbbl_a.htm, 11 May 2007.

[14] Calculated assuming 19.654 pounds of carbon dioxide per gallon of gasoline, per U.S. Department of Energy, Energy Information Administration, Voluntary Reporting of Greenhouse Gases Program, Fuel and Energy Source Codes and Emission Coefficients, downloaded from www.eia.doe.gov/oiaf/1605/coefficients.html, 10 January 2006. Total gasoline consumption from U.S. Department of Energy, Energy Information Administration, Prime Supplier Sales Volume for 2005, 10 May 2007. Based on an assumption of 596 gallons of fuel per vehicle.

[15] Annual highway gasoline consumption of 8.3 billion gallons in Florida in 2005, 15.6 billion gallons in California and 11.3 billion gallons in Texas from U.S. Department of Transportation, Federal Highway Administration, Highway Statistics 2005, downloaded from www.fhwa.dot.gov/policy/ohim/hs05/index.htm, 10 May 2007.

[16] Current price of gasoline from U.S. Department of Energy, Energy Information Administration, Gasoline and Diesel Fuel Update, 14 May 2007.