Boy, do we ever have the problem in Phoenix. You can definitely see the effect during our monsoon season when huge thunderering storms hit the heat island and simply whisp away instead of drenching the main part of the valley.

One interesting phenomena is this new rubberized asphalt layer (created with recycled car tires) they've been adding to the freeways for the primary purpose of noise reduction. It's amazing when you hit those patches how quiet your car becomes. The neighborhoods around the freeways certainly love the silencing effect as well.

Turns out there's this additional benefit nobody ever dreamed of. You'd think, from looking at the new layer, that it would retain more heat since it tends to be much more black than the standard asphalt surface. However, when they did aerial monitoring with infrared sensors of the valley, these cool lines showed up wherever the rubberized coatings were applied. Turns out this compound does not trap heat or releases it quickly.

I'd be willing to bet we could make the most impact though by simply requiring any building roofs to be constructed out of light colored or reflective materials.

Art