American emit 4.3 million fewer tonnes driving

CNN reports that Americans are drove billion fewer miles in May than they did in May '07.

With high gas prices and a slowing economy, Americans are now taking fewer trips by car and are starting to rely again on muscle power to get around.

If we assume that the average fuel efficiency for all vehicles is 23.1 miles per gallon, that translates to 4.3 million fewer (metric) tonnes of greenhouse gas emissions.

That's the equivalent of 2200 tonnes of coal not burned.