They do quite well in a crash test, better than some small cars, and better than most large SelfishUrbanVvehicles.
the car does have a rigid body compared to other compacts but it also means larger transfer of force to the occupants. there are no crumple zones in the smart car frame. its product brochure only mentions that the rigid frame of the car "should trigger crumple zones" of the other vechile during a collision. and that is supposed to be a selling point? i wouldnt want to be in a smart car during a collision.
like other have already said... the smart car is more expensive than the corolla and other compact cars. with the same mileage but without the rear seat and trunk space it is not a good value. that is the reason why it has been in a test market in seattle for almost 7 years now and it still has not picked up enough support from consumers. only in california and in particular hollywood has the smart car become the item to buy because it is more a status symbol than a serious attempt at conservation.