In most of California it seems that the next set of lights turns green as soon as the previous set turns red. In Ontario, Canada I believe there is a 2 or 3 second delay. I don't think that I've noticed any difference in the behavior of people around yellow lights except for the fact that in California it seems people are more willing to run red lights, and the intersection is almost never clear when the next green light happens (unless, of course, traffic is sparse). In Ontario, Canada the intersection is almost always clear when the next green light happens.