Mr. Obama wants to push up the effective date of the 35 mile a gallon fuel economy standard former Pres. Bush approved in the 2007 energy bill, from 2020 to 2016.

Administration officials say a 30% reduction would eliminate 900 million tons of greenhouse gas emissions, and they say a 30% increase in fuel economy would reduce our oil imports by 1.8 billion barrels, between 2016 and 2020. That's the equivalent, they say, all the oil imported during a year, from Saudi Arabia, Venezuela, Libya and Syria. It's also the equivalent of taking 58 million cars off the road for an entire year.

Since there are 250 million cars on the road in the USA, "the equivalent of taking 58 million cars off the road for an entire year" over the 4 year period between 2016 and 2020 would reduce emissions by (58/250)/4)... for a total reduction of 6% of emissions from cars, between 2016 and 2020.

So it's fair to say that Obama is 6% better than Bush on the issue of automobile emissions.

But that's only between 2016 and 2020, and after 2020, the Bush plan to reduce automobile emissions and the Obama plan to reduce automobile emissions are exactly the same!