Aerodynamic Trucks
 

I spotted a teardrop shaped truck yesterday. Boy was i surprised!
M and S Cuts Carbon With Teardrop Trailers*

NASA, MAN, Dolphins, Teardrops, Labatt's beer and Marks & Spencer ladies underwear...where else would you find them altogether but Biglorryblog? - Biglorryblog

10% fuel savings apparently. Not a small amount considering how much they use overall.
http://ecomodder.com/forum/member-vt...-treadrop3.jpg

Lately, I've seen a few 18-wheelers with a long V-shaped air dam under the trailer to direct air flow to the outside of the trailer tires. I've also seen a number of 18-wheelers with side skirts.
Anything to improve efficiency helps.