Originally Posted by Rodney

First, you might meet someone jumping the gun in the other direction. Second, the lights might be mistimed so that the yellow is still shining in your direction while the lights switch to green for the intersecting street. This happend to my wife; she crossed on a yellow and a car t-boned her from the crossstreet. She knew she was on yellow, the other guy swore his light was green. The insurance company divvied up the blame more or less equally. Later, she went back to the intersection to check things and, sure enough, the yellow and green lights for the intersecting streets overlapped by one second.

She never did go back and sue the city, but she should have.