Jeremy Cato writes another article about aerodynamics. Misinformation ensues.

[brucepick]

My understanding is, the back end of a car potentially has more effect on the overall c/d than the front (unless you go drastic in front, with a long slope like basjoos). We don't have a really good view of the back but I can see the final cross sectional area is still pretty big. That's what determines the overall size of the wake, correct?

As for the rest - if they really want to drop the c/d, the car needs a full belly pan. But they don't get 'cool' or bling points for that so might not do it. Would be a shame to not treat the underside though; it should be cheap to build and no 'styling' penalty for using an optimum design.

[PaleMelanesian]

The new Prius does in fact have smooth belly panels. GM should definitely take notice.

[tasdrouille]

Originally Posted by Southcross

lawls... I bet the mirror design shaves 3pts off the cD

Actually, some people furiously argued that the mirrors were not causing drag at all. So they must have been shaving points to compensate for their area...

Not that I believe it's the case though...

[MetroMPG]

Originally Posted by brucepick

I can see the final cross sectional area is still pretty big. That's what determines the overall size of the wake, correct?

Correct, assuming attached flow to the cut-off. It's not significantly different than the Prius rear end.

As for the rest - if they really want to drop the c/d, the car needs a full belly pan.

If they have in fact managed to beat the Prius 0.25 figure, you can be sure they have paid attention to smoothing the underside. The bottom of the Volt's battery pack itself will be flat, and it occupies a significant amount of the underside real estate.