In summer, the nearly empty streets of metropolitan Phoenix resemble the old days on Main Street in small town America with light traffic and courteous drivers waiving to one another.   No, not really, but in the autumn, the change in traffic conditions is dramatic.  Anyone who commutes or drives in Maricopa County can see the difference that the cooler weather has on traffic. By this time, the kids are back to school, the snowbirds are back, the retirees return and the affluent return from vacations in San Diego. In my Phoenix personal injury practice, we see this pattern every year - October first brings more phone calls about car accidents. So, enjoy the nice weather, stay patient with the traffic and be careful out there.