The Facts
Cars and light trucks generate over 1 billion tons of greenhouse gases in the U.S. alone, or 18% of total U.S. greenhouse gas emissions (EPA).

New 2020 CAFE Standard Too Weak
In 2008, the combined fuel efficiency for passenger cars and light trucks in the US is approximately 24 MPG, while it is already 44 MPG in Europe and 47 in Japan, almost double that of the US!

Why should we wait until 2020 to get a lower average MPG in the U.S. than Japan and Europe already have today?

Source: http://www.pewclimate.org/global-warming-in-depth/all_reports/fuel_economy