Let'sgoflying! said:
why wouldn't they be legal here? too much pressure for the oil industry?
No, Dave, they are simply not that great as cars, the market doesn't really want them and, hence, the manufacturer has not spent the time and effort to certify them and establish as support network for them.
The fuel mileage is not appreciably greater than many other small cars (Jetta, Corolla, Civic, you name it), but they are dramatically less safe in collisions with full-sized automobiles. In addition, performance is inadequate for most US use.
They are exceptionally well-adapted to use in very dense urban areas, but most people whose travel is limited enough to such areas don't use cars anyway; they use the well-developed public transport which typically exists in dense urban areas.
The Smart has never been a success in Europe, either (oh, they've sold some, but never enough to make it a viable product in its own right).
Opportunism, nothing else. If I wanted to get a really economical car right now- fuel mileage a primary deciding point- I'd get a VW Jetta with the direct-injection turbo diesel (TDI). Great performance, roomy, comfortable and super real-world mileage.