"People do have a right to be stupid
....
I'm all for government staying out of our lives as much as possible but if a few laws being passed requiring builders to only install light colored roofs ended this obvious man-caused phenomena, I could easily sign on. The stupid people will find many other freedoms to practice their craft."

Instead passing laws, if govt did things to encourage more awareness about how having light colored or white roofs and that this would save them money [and make their local area and larger area have less Heat island effect] then it seem likely that more people will consider this when making these kind of decisions [instead of simply not caring very much or be more concerned with what would be a "nice color" or "normal color".
Also govt is largely the decision maker in regards to roads, so if some effort is made shopping or promoting the idea that they want to pay perhaps a bit more or will choose a contractor that uses material which causes less heat island effect, then that should bring about desired changes. This also applies of course to govt buildings.

If people were as 1/2 as aware of Heat island effect as "global warming", then we would half way to to solving the problem without any really significant cost. I actually believe that *because* of "global warming" hype less attention is paid to this much more significant issue- I say this because it seems to me that there was a growing awareness of this issue at around the time more media coverage was being devoted to "global warming".

I also think more attention should devoted to bringing about darker skies in urban areas, and I think it should done in a similar manner- meaning promote public awareness and do things that govt is directly responsible for [e.g street lamps].