Clogged highways and frustratingly waiting while your gas needle plummets to empty usually doesn't conjure up thoughts of green, but it seems like these very roads could become the source of a lot more energy. Several recent student designs have proposed that major roadways be retrofitted with various forms of wind energy collection devices, ranging from overhead turbines that collect energy from quickly-moving cars below to barrier panels (pictured after the jump) that harness the wind from closely passing vehicles moving in opposite directions. Ideally, the wind energy could then be sent back out to the grid to power nearby communities, light-rail transportation systems, or even intelligent billboards. Of course, most of these ideas are still in the research phase, and even if proven feasible, we can't imagine the up-front costs (or inconveniences of installing these things) to be minor, but we're sure that government subsidies should be able to to lend a helping hand.

Read - Barrier panel prototype, via Inhabitat
Read - Overhead turbine design, via Inhabitat