We've seen prototypes of Jersey barriers that use the breeze from passing cars to create electricity, and now a student at Arizona State University has a plan to "retrofit" the steel tubes that hold highway signs to do the same thing.

The student estimates that if he replaces signs on the highways outside of Phoenix, where the wind averages 10 mph and cars drive at 70 mph, each turbine would produce enough energy annually to power a 700-square-foot apartment. That may not sound like a whole lot, but if either the Jersey-barrier or road-sign system could be made to work without forcing cars to burn excess gas, it would be an easy way to harvest a little extra energy.

We're hoping that the student plans to keep some of the old-fashioned highway signs around: From the look of this Photoshopped image, the signposts probably couldn't hold both a sign and a turbine at once. — S.E. Kramer

Archinect, via Treehugger