I went and checked out the SmartCar site - it says the SmartCar gets worse mileage (under equal 2008 standards) than what is promised by the Civic Hybrid. (40 / 45 for the Civic, 33 / 41 for the SmartCar)
I can't imagine sacrificing the space and safety and actually using more gas! I know the Civic costs 8-10 thousand more, but would you ever use the SmartCar as your ONLY car? Would you take it on the road to Atlanta? Not more than once, I imagine. I bet the Canadians who brought theirs down trailered it behind their RV.
They are popular in Europe because of a lack of parking/garage space. That's not our biggest problem, our biggest problem is fuel use.
I'd rather see more plug-in hybrids or pure electric vehicles than SmartCars (unless they make them electric......)