A Yellow Traffic Light Means Stop
Believe it or not, in British Columbia a yellow traffic light tells you that you must stop before you enter the intersection! Yes, I know that there is one caveat to that statement, and it is "unless the stop cannot be made in safety." The onus is on the driver that does not stop for the yellow light to show that it was unsafe if they are involved in court proceedings because of their decision.
Is anyone able to tell me what a stale green light is? That's right, it's a traffic signal that will soon be turning from green to yellow. An example of a stale green light would be one that you have not seen turn green so that you don't know how long it has been that way, one that has a solid red hand "don't walk" signal facing the same direction of travel or perhaps the cross street has many vehicles waiting for the red.
The proper response when approaching a stale green light is to shadow the brake pedal. This means lifting your foot off of the accelerator and hovering it over the the brake. If a stop is needed, you are already almost there as you are beginning to slow and ready to brake.
Couple this with advance warning lights of a signal change and awareness of surrounding traffic and road conditions and the only reason to not stop at a yellow light may be that the light changed when you were so close to the intersection that you had reached the point of no return.