FRANKFURT -- Rear fender skirts certainly make a car appear sleek and extremely aerodynamic. So it is just a matter of time before they become standard equipment on all cars, right? Automakers ...

And why not? The original Honda Insight, sleek and teardropped like a little glass slipper, had the lowest coefficient of drag on any production car in 1999, at 0.25. The half-hidden rear wheels, ...

Let's face it: Most fuel-saving adaptations for existing cars either turn drivers into total road-hogging jerks, or are simply flat-out gimmicks. Hypermiling sounds great, but just try explaining it ...