Since 1981, the top selling car in the US has not been a car, but a truck. The Ford F150 has consistently been the top selling vehicle. In May, in a remarkable change, the Honda Civic has jumped to the top of the list.

Is this a sea change? Or a temporary bump? Clearly fuel prices are high, and that leads to changes in behavior, but will it extend to support for other greener choices?

If someone can produce ethanol for $1 a gallon, as has been claimed, will small efficient cars remain popular, or will we instantly see a return to big trucks and SUV's?