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Department of Transportation releases greenhouse gas study

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The Department of Transportation has released a study suggesting a number of strategies to reduce greenhouse gas emissions from transportation. "Transportation's Role in Reducing U.S. Greenhouse Gas Emissions" identifies options such as using low-carbon fuels, increasing vehicle fuel economy, improving system efficiency and reducing travel that involves high levels of carbon emissions.

“Reducing the greenhouse gas emissions that contribute to global climate change is one of the great challenges of our time,” said U.S. Transportation Secretary Ray LaHood.  “Transportation is one of the major contributors to greenhouse gases, and the transportation sector must be a big part of the solution.  This report provides valuable information that will help us in our effort to protect the environment.”

According to the report, U.S. vehicles account for 29 percent of all U.S. greenhouse gas emissions and 5 percent of global emissions. Most of those emissions (59 percent) come from light-duty vehicles, followed by freight trucks at 19 percent and aircraft at 12 percent.  Between 1990 and 2007, the report notes, greenhouse gas emissions from U.S. transportation increased 27 percent, and accounted for almost one-half of the total national increase during that period.

The report analyzes the full range of strategies available to reduce transportation’s greenhouse gas emissions, but makes no specific recommendations.  Among the findings:

  • More fuel efficient gasoline vehicles could reduce per-vehicle emissions by 8 to 30 percent, hybrid vehicles 26-54 percent, and plug-in hybrids 46-75 percent.
  • More direct routing of airline flights using NextGen technology and more efficient takeoffs and landings could reduce aviation greenhouse emissions by up to 10 percent by 2025.
  • Reducing the number of vehicle-miles traveled through a combination of  improved public transportation, coordinated transportation and land use strategies, and greater opportunities for walking and biking could reduce transportation greenhouse emissions 5 to 17 percent by 2030.

The 605-page report also discusses policy options for implementing these strategies, such as efficiency standards, transportation planning and investment, market-based incentives, research and development and economy-wide carbon policies.

The department says work has already begun in these areas. 

“Earlier this month we established historic new fuel economy standards that will save nearly a billion tons of greenhouse gas emissions over the lives of the vehicles covered,” said Secretary LaHood.   “In aviation, DOT has put energy and environmental concerns at the heart of NextGen - the iniative to modernize the U.S. air traffic system.   The Department’s Sustainable Communities Partnership with EPA and HUD is providing low carbon transportation options.” 

The report, Transportation’s Role in Reducing U.S. Greenhouse Gas Emissions, was mandated by the Energy Independence and Security Act of 2007.