What I wish they would do is add a countdown timer to the yellow, so you know if you can make it or not; make the number black on yellow, or make the yellow blink (rate->faster) as it gets closer to switching to red. Anything. Then again, these are the same tards who install red-light cameras then decrease the yellow time to boost revenue.
Right now I tend to use the countdown timer crosswalk signals (if they are available) to know how long I have before the light starts to change; but this can be distracting (I glance at it when I am further away from the intersection, and count down with it - I don't look at it constantly while I am driving toward the intersection). Plus, sometimes things are arranged where it is "stop" for pedestrians but still "green" for cars going in the same direction (likely for left turners or something), so this method isn't foolproof.
Maybe you could modify your Arduino code to do simulate this idea (do they sell bi-color LED 7-seg displays?)... 