Yellow light turns are predictable in that you know that they'll happen, just not when. So if you have a heavy load or other adverse conditions you should slow down to a speed where you could stop at the correct distance. Software should do an even better job of predicting the weight to speed to stopping distance ratios.

You don't know how long the yellow light will last before turning red. That time is variable from light to light and essentially unpredictable to drivers.

What is a safe speed to drive when you take into account that the yellow light may last from less than a second to 20 seconds?