Some of the best inventions are simple and elegant, and when I first heard about this I thought, why has this not been done before?
Of course it makes perfect sense. Black things, like black asphalt, absorb heat. Any of you who have been to a hot city will know the feeling of the heat baking off the street in a disgusting humid wave. So, why not combat this by painting the roads white?
They mention in the video that they are testing this in LA, and that they are using an extra special kind of paint which is quite expensive but particularly suitable to reduce the temperature in the city. Despite its cost I do think that, if it works, this cost is mitigated by the reduction of costs associated with care for people suffering heat stroke, the reduction of cost of air conditioning, and of course the reduction of CO2 emissions associated with the extra power normally used for those air conditioners.
I am very curious to see the results of this experiment. In the meantime, good on LA for trying it out.