Should President Obama ride in an environmentally "green" limousine?

I find questions like yours to be very silly. They are attempts to portray presidential actions as hypocrisy when being President is obvious a very special case. The presidential limousine is a very special vehicle that has armor plating, bullet-proof glass, countermeasures against rocket propelled grenades, its own oxygen supply, firefighting systems, communications equipment, etc. These things are in place to ensure the security of the President of the United States. With systems like those installed, the car will never be "green" and to think that it should be is ridiculous. As your link states there are something like 600,000 federal vehicles, and making the vast majority of those "green" would be a big accomplishment, but if certain vehicles cannot be modified because of their particular use that's perfectly understandable...at least by most people.