Mercedes C Class patented ventilated tail lights
 

aw this on Fifth Gear and went straight to the web to find out more...

http://www.blogsmithmedia.com/www.au.../02/cclass.jpg

High pressure air from under the car is vented at the leading edge (side) of the tail light assemblies.

Apparently this accomplishes 2 things:

1 - relieves under car pressure, reducing lift and eliminating the need for a deck lid spoiler

2 - interacts with the flow at the transition at the rear of the car in a way that reduces turbulence, reducing drag.

The car has a decent (for modern production cars) cd of 0.27.

http://images7.worldcarfans.com/news...208.004.1M.jpg

More info:

http://www.autoblog.com/2007/02/09/m...ted-taillights

http://www.worldcarfans.com/rsslink....ed-tail-lights

Is it possibly just marketing hype?

Maybe.

But they do claim 0.27. So there is some proof in their pudding. Though how much the vents contribute isn't stated - and there's still piles of room for improvement, and not just this incremental stuff we're seeing.

The number of current production cars with a Cd of .27 is small.