The problem is that people tend to interpret a green light to mean "you can go" rather than "this specific light isn't telling you to stop". Hence all those sig

The problem is that people tend to interpret a green light to mean "you can go" rather than "this specific light isn't telling you to stop". Hence all those signs that say something to the effect "turning cars yield to oncoming traffic on green" as a reminder. And the effect is likely worse for a green arrow, which implies having the right of way.