Having red lights transition to yellow before switching to green is such an obvious optimization, I don't know why every country hasn't adopted it as the standard.
Discussion
It is true, why don't they do that. While some parts of Japan have pedestrian-vehicle separated traffic signals, I think that could also be a good countermeasure.
The actual optimization is roundabouts.
Seems like it could cause confusion in certain situations if yellow precedes both the stop and the go
In some countries orange (quite similar to yellow) means you can pass but you don't have priority, that can lead to confusion IMO