What about in the cooler months? Then you might be actually wanting to take advantage of the higher roof temperatures from solar radiation. I use a system in my house (in Auckland, New Zealand) where warm air is extracted from the warm roof space, to help warm (and ventilate) the house (in the cooler months). It works well but the roof does get excessively hot (60+degrees C or 140+ degrees fahrenheit) in summer and I'm sure that contributes to the house temperature getting too hot in summer. It's a pity you can't have a white roof in summer and a dark one for winter. :-)

Global warming would have been believable if the Greenies had stuck to these sort of simple, inexpensive solutions that make clear and obvious sense.
But nobody gets rich just painting rooftops. So instead we were told to send billions to African dictators and subsidize wind and other alternative energy boondoggles that enriched Al and half the UN...to keep half the earth's surface from flooding and preventing the deaths of billions by this time.
Now that the Chicago Carbon Credits Exchange is closed and the windmills are shutting down, the enviros are left to ponder other 'sustainable' schemes to fund their retirements with.

How about white roads... those take up a lot of space and most are black

As usual Todd has nothing to add but fear, hate and conspiracy theories that ignore science. If it's a hot day do you wear a dark shirt that makes you hotter, or a white one that keeps you cool? The white glaciers are disappearing and the world will get hotter, we're adults and we feel it is our duty to do what we can to slow this. If he knew how much money could be made in paint he would probably think this science is a conspiracy too.

re; Theo Viljoen
And with catalytic cracking a waste of perfectly good oil.

What a waste of energy. Why not use a solar capture system and utilise the power to help reduce the cost of running the buildings.
Why would you want to throw away all that energy by directing it staight back into space???

Please take note, residents of Perth, Western Australia. When visiting in Nov 2011, I was told that it's trendy to have dark grey tiles on your roof. I saw lots of evidence of this. Presumably the air conditioning industry is faring well. Frank Bremner, Somerton Park SA.

@Tommygun: I don't think the white roof in summer and a dark one for winter would be of much use since the dark roof would lose heat faster than a light one (via radiation) in cold weather. Polar bears have white fur for camouflage, but if it meant that they lost body heat faster then they would not have survived. With white tiles on your roof the heat generated within the house will be trapped in your ceiling space for you to harvest.

You are on the right track. now plant on all flatroofs and you really lower temperatur, reduce rain run off significantly, help reduce co2 and on and on
use nature to bring your good idea to life!

People have been doing that for years on Airstream trailers. Factory does it now. SkipJ