How to reduce GHG emissions in transportation sector; Is it possible?

The U.S. Department of Transportation published a report of strategies to reduce the United States' greenhouse gas emissions in transportation sector.
The report comprises two volumes of about 600 pages. The first volume is a synthesis report and the second volume is a technical report.

They summarized the strategies in six categories:

1. Introduce low-carbon fuels (ethanol, biodiesel, natural gas, liquefied petroleum gas, synthetic fuels, hydrogen, and electricity)
2. Increase vehicle fuel economy (increased fuel economy in light-duty vehicles; retrofits; fuel economy improvements in rail, marine, and aviation sectors)
3. Improve transportation system efficiency (lowering speed limits on national highways; traffic management and bottleneck relief; direct routing and more efficient takeoff and landing in aviation)
4. Reduce carbon-intensive travel activity (a fee per vehicle-mile of travel (VMT); an increase in the motor fuel tax; significant expansion of urban transit services; land use changes; pedestrian and bicycle improvements)
5. Align transportation planning and investments to achieve GHG reduction objectives
6. Price carbon (a cap and trade system or carbon tax)

To make the strategies come true, the U.S. DOT suggests five policy options.

1. Efficiency standards (fuel economy standards, low carbon fuel standards, and GHG emissions standards)
2. Transportation planning and investment (Federal technical assistance in integrating transportation and land use planning, and ensuring integration of climate change considerations into transportation planning and funding programs in order to prioritize GHG reducing strategies)
3. Market-based incentives (tax credits, feebates, subsidies, and vehicle miles traveled fees)
4. Research and development (research on advanced vehicle and fuel technology and research to develop data, tools, and decisionsupport to inform transportation planning and investment processes)
5. Economy-wide price signal (a cap and trade system or a carbon tax to establish a carbon price)

The report says,
"Confronting climate change is a top priority for the Obama Administration."
It is true. However, GHG emissions reduction is just 'a' priority, neither 'the most import' nor 'the most urgent' priority. The hegemony fight in politics, dis-information among voters, hardly-changing economic theories, fluctuating weather (not climate) events, survival wars between nations or companies in ever-growth-pursuing economy, ... These things make solutions unforeseeable in the real world.

Source: Center for Climate Change and Environmental Forecasting. (2010). Transportation’s Role in Reducing U.S. Greenhouse Gas Emissions (Volumes 1 and 2). Washington, DC: U.S Department of Transportation (DOT). [Full-text at http://bit.ly/c0w0F7]