A greener shade of cool

The Duffy charter school in Phoenix is a test ground for a light-colored covering over its asphalt parking lot, which is 30 degrees to 40 degrees cooler than black asphalt. Interest in reflective surfaces, including white "cool roofs," is growing as a relatively easy and inexpensive way to reduce the urban heat island effect and mitigate global warming.

See related article: 'Green asphalt' layers cool surface on school lot.