You guys are right about the "heat islands". In the summer I run at o dark thirty to get it in before the sun comes up. We have some spots of open desert and you can actually feel the temperature difference from when your running next to houses to open desert.
The last few years they have been repaving all the highways with rubberized asphalt to help with the heat island effect. It uses old tires and it also cuts down on the road noise. But when they showed an infrared image over the highways that had been repaved vs. the sections that had not it was a dramatic difference.
