In California the yellow light only means that a red light will soon appear. If you enter the intersection while the light is yellow, you are okay, even if the light turns red while you are in the intersection. This is our state law, but it's not the law everywhere. I stop for yellow if it is safe to do so - unless it's one of those intersections where I will have to sit for an extended period of time if I catch the red. Then I really, really try to get through the yellow, but only if I am 99% positive that I will make it into the intersection before the light turns red, and that I won't be blocking the intersection because of traffic being backed up in front of me.