WASHINGTON - MAY 21: U.S. President Barack Obama (3rd-L) speaks at the Rose Garden of the White House as EPA Administrator Lisa Jackson (R), Director of the White House Office of Energy and Climate Change Policy Carol Browner (L), and Transportation Secretary Ray LaHood (2nd-L) listen on May 21, 2010 in Washington, DC. Obama signed a presidential memorandum to push for producing more fuel efficient trucks and next-generation cars, including advanced electric vehicles. (Photo by Alex Wong/Getty Images)
